Aggregation of direct dyes investigated by molecular modeling
Molecular modeling simulating aqueous conditions is used to elucidate the formation of aggregates of sulfonated chromophores, including Congo Red and Trypan Blue. The relative energies involved in the aggregation process are calculated and geometric features of the molecules and their aggregates are discussed. Parallel stacking facing one another occurs with slight shifts along the long axes of the chromophores to accommodate the sterically demanding sulfonate groups. The Connolly surfaces and volumes of the individual molecules as well as their aggregates are determined.
As part of a larger investigation using direct dyes as molecular sensors to characterize different cellulose substrates, we noted that the tendency of these dyes to form aggregates requires elucidation. Results from our dyeing experiments [3] appeared to indicate that, even when dilute solutions of the dyes were employed to obtain Langmuirian adsorption, aggregates of different sizes rather than single molecules might have been adsorbed onto the surfaces, depending on the dye. Thus we used molecular modeling to obtain a better understanding of aggregate formation under these conditions.
Molecular modeling has been successfully applied to a diversity of problems to characterize properties that are extremely difficult to assess by experiment [5, 6, 9, 11]. With respect to dyes, molecular modeling has been employed, for instance, to characterize the geometry of direct and disperse dyes [7, 10, 17]. Aggregation was modeled by Skowronek et aL [12, 13], who extensively used various modeling techniques and force fields to elucidate the geometry and self-assembly of direct dyes. The supramolecular organization of Congo Red was studied because of its unusual complexation characteristics associated with liquid crystal formation. Since liquid crystal formation requires high concentrations of electrolyte and dye, the dyes were modeled in their neutral form. A critical consideration is the fact that modeling calculations are typically based on a gas phase model at a dielectric constant of 1 [11]. However, this class of dyes is usually applied from aqueous solution. Of concern, then, is the question of how well such modeling calculations relate to the solution state. Modeling software addresses the problem in various ways. The molecular mechanics software (Amber 4.1) used by Skowronek et al. [13] permits placement of a water shell around the supramolecular system while maintaining a dielectric constant of 1.
Urukawa et al. [16] used Allinger’s MM2 force field to study aggregation of acid dye molecules, including Azorubin, in order to estimate intermolecular distances between the two molecules forming a dimer. These researchers reported a shifted, parallel-stacked geometry for the Azorubin dimer with an intermolecular distance of about 6A. In general acid dyes are smaller than direct dyes, but are similar to the latter in that they are also azo dyes and have negatively charged sulfonate groups. Azorubin consists of a naphthalene ring connected at its 4-position by an azo-linkage to the 7-position of a second naphthalene group.
For this study, we use molecular mechanics calculations to generate geometries and energies involved in aggregation processes of six direct dye molecules. The dyes are presented in Table I together with the codes used in the text. Five of the molecules under investigation for this study-C.I. Direct Red 28, C.I. Direct Red 2, C.I. Direct Blue 1, C.I. Direct Blue 14, and C.I. Direct Blue 53-are related in that they have the same backbone (Figure la, b). However, dyeing experiments have shown that they can differ significantly in dyeing behavior [3]. It appears that the type, number, and position of functional groups help determine their aggregation properties, which in turn, may affect their dyeing behavior.
Thus our goal in this work is to use molecular modeling as a tool to explore what kind of aggregate formation is possible, the geometries involved, and whether there is a limit beyond which aggregate growth is no longer energetically favorable. In addition, we determine the Connolly surfaces and volumes of the individual dye molecules and their aggregates to obtain an estimate of their size.
A Connolly surface is the van der Waals surface of a molecule that is accessible to a solvent molecule, in this case water. Such a surface is generated by rolling a probe sphere over the van der Waals surface of the molecule of interest. The surface consists of three components: contact, saddle, and concave surfaces. The contact surface comprises those atoms that are accessible to the probe sphere. The saddle-shaped and concave surfaces are denoted as reentrant surfaces and represent the boundary at the volume from which a probe sphere is excluded if it is not to experience van der Waals overlap with the atoms .
Cerius 2 by Molecular Simulations Inc. with the Universal Force Field was employed, as well as CAChe by Oxford Molecular Group. For all experiments performed with Cerius 2, a dielectric constant of 78 was used corresponding to water. The temperature default was absolute zero. Geometry optimizations of one to ten molecules per aggregate were performed for the six dyes under investigation. All dye molecules were treated in their anionic form to model the system as closely as possible to our experimental practices, i.e. aqueous solutions at low concentrations of dye and electrolyte. Under such conditions, the anionic chromophore and its counterion are separated by a large distance [81, such that in this exploratory investigation, the Na+ counterions were omitted. Geometry optimizations of all individual dye molecules were performed prior to assembling them into various starting positions for the aggregation experiments. Geometric optimization procedures on larger aggregates (those containing three to ten chromophores) were performed by manually assembling individually optimized molecules and/or dimers. Intermolecular distances for the manual placement of individual molecules forming dimers, two dimers forming aggregates containing an even number of molecules, as well as individual molecules and dimers to build aggregates with odd numbers of molecules per aggregate, were manually varied from approximately 2.5 to 20Angstrom. Only the most energetically favorable configurations of the dimers were stacked for aggregate assembly. Stacking occurred with the ring systems of the chromophores lined up face-to– face.
The Connolly surface areas and volumes were calculated for all single molecules and all aggregates. Dot displays of the van der Waals surfaces were generated to illustrate the solvent accessible surfaces of the molecules and aggregates. To calculate the Connolly surface areas of the molecules and aggregates, the probe sphere radius was set to 1.4Angstrom, corresponding to the van der Waals radius of water. Conformational analyses were performed with CAChe using the MM2 force field.
Skin salvation: slough off scaly winter skin and perk up drab coloring with luscious—and cruelty-free—natural cosmetics
Don’t blush. With three solid months of winter behind us, no one will blame you for having the skin of a cranky crocodile. “When the temperature drops and the relative humidity decreases, the upper layers of your skin lose a large amount of water,” explains dermatologist Jerome Z. Litt, MD, in his book, Your Skin From A to Z. And because the moisture in deeper layers can’t work its way up to the surface, the result is “scales” and flakes on skin’s top layer.
Skin isn’t safe indoors either. “The lower humidity is aggravated by artificial heat, which, in addition to warming the air, dries it,” writes Litt. That dry, heated air sucks moisture out of everything–including skin.
At the end of winter, as humidity rises and we stop turning up the heat, skin will slowly return to normal. But why wait? This is the ideal time to jettison your usual products and try something new. To get you started, we went searching for body care companies offering organic, pure products–an approach that’s sensible no matter what your skin type. “Most people have some kind of sensitivity,” says Los Angeles–based dermatologist Debra B. Luftman, MD. “The more preservatives and perfumes a product contains, the greater the possibility that it will irritate skin.”
The people who make the following products list the ingredients on either the package or their websites. All of these companies are also committed to making the planet a better place–whether by supporting fair trade or by urging consumers to recycle used shampoo bottles–and their products are cruelty-free. Which means that even your inner reptile will feel well cared for.
Fluorescence lifetime spectroscopy in multiply scattering media with dyes exhibiting multiexponential decay kinetics
ABSTRACT To investigate fluorescence lifetime spectroscopy in tissue-like scattering, measurements of phase modulation as a function of modulation frequency were made using two fluorescent dyes exhibiting single exponential decay kinetics in a 2% intralipid solution. To experimentally simulate fluorescence multiexponential decay kinetics, we varied the concentration ratios of the two dyes, 3,3-diethylthiatricarbocyanine iodide and indocynanine green (ICG), which exhibit distinctly different lifetimes of 1.33 and 0.57 ns, respectively. The experimental results were then compared with values predicted using the optical diffusion equation incorporating 1) biexponential decay, 2) average of the biexponential decay, as well as 3) stretched exponential decay kinetic models to describe kinetics owing to independent and quenched relaxation of the two dyes. Our results show that while all kinetic models could describe phase-modulation data in nonscattering solution, when incorporated into the diffusion equation, the kinetic parameters failed to likewise predict phase-modulation data in scattering solutions. We attribute the results to the insensitivity of phase-modulation measurements in nonscattering solutions and the inaccuracy of the derived kinetic parameters. Our results suggest the high sensitivity of phase-modulation measurements in scattering solutions may provide greater opportunities for fluorescence lifetime spectroscopy.
Fluorescence lifetime spectroscopy is especially advantageous for quantitative biomedical spectroscopy of analytes since the measurement of fluorescence decay kinetics (rather than the fluorescence intensity) eliminates the necessity for the knowledge of the analyte-sensing fluorophore concentration. Frequency domain techniques provide measurement of fluorescence lifetime (tau) using simple relationships of the phase-delay (theta) and amplitude-attenuation (M) of the reemitted fluorescence as a function of the modulation frequency relative to intensity modulated excitation light. However, the development of fluorescence lifetime spectroscopy for near infrared (NIR) biomedical tissue diagnostics for sensing using systematically administered dyes (Hawrysz and Sevick-Muraca, 2000; Weissleder et al., 1999) or implantable devices (Qing et al., 1997; Russell et al., 1999) requires 1) deconvolving the influence of multiple scatter upon the measured emission phase-delay and amplitude-attenuation measured in the NIR wavelength region and 2) accounting for nonsingle exponential decay kinetics.
Most fluorophores capable of analyte sensing exhibit multiexponential kinetics. For example, Ca^sup 2+^ (Lakowicz and Szmacinski, 1992) and pH (Lakowicz and Szmacinski, 1993) sensing with fluorescence lifetime spectroscopy in dilute, nonscattering solutions requires determination of multiexponential decay kinetics for accurate analyte sensing. Accurate fluorescence lifetime spectroscopy in the presence of tissue-like scattering requires a model that accounts not only for photon propagation but also for multiexponential decay kinetics as well. Indeed, the fluorescence resulting from ultraviolet excitation of the normal and athlerosclerotic arterial wall also shows multiexponential decay kinetics of its excitable constitutes (Andersson-Engels et al., 1991). Because ultraviolet light does not multiply scatter in tissues, deconvolution of the influence of scatter is not necessary. In contrast, failure to properly account for multiply scattered NIR excitation and emission light in tissue or within a scattering solution can result in erroneous identification of intrinsic decay kinetics. Upon conducting phase-modulation measurements on a solution of intralipid containing the NIR excitable fluorophore, indocyanine green (ICG), Lakowicz and Abugo (1999) did not incorporate the propagation of light, yet attribute multiexponential decay kinetics to this dye, which typically exhibits single exponential decay kinetics.
Approaches to appropriately model the multiple scattering of NIR excitation and fluorescence photons and to use diffusion models for quantitative spectroscopy have been previously demonstrated (Hutchinson et al., 1996; Cerussi et al., 1997; Mayer et al., 1999) for dyes exhibiting single exponential decay kinetics. Because most dyes exhibit multiexponential decay kinetics or exist within two or more different states, lifetime spectroscopy within tissues or other scattering media must consider kinetics beyond simple, first order decay. Indeed, the presence of scattering increases the sensitivity of frequency-domain measurements and accurate kinetic models need to be considered. However, to date, there has been no attempt to perform lifetime spectroscopy of dyes exhibiting multiexponential decays in tissue-like scattering media. Herein, we present a model-based, experimental study of fluorescence involving two dyes with distinctly different lifetimes combined together at various concentration ratios in a multiply scattering medium. By varying the concentration ratios of short- and long-lived dyes, we tested the models and identify a feasible approach for quantitative characterization of multiexponential decay kinetics in tissues as well as in implantable sensors.
Dermorubin and 5-chlorodermorubin natural anthraquinone carboxylic acids as dyes for wool
Wool is dyed for the first time with a mixture of two pure natural anthraquinone carboxylic acids, dermorubin and 5-chlorodermorubin (2:1), by means of the acid dyeing technique. The anthraquinone carboxylic acids are isolated from the fungus Dermocybe sanguinea and separated by multiplicative liquid-liquid partition using a stepwise pH gradient. The color of the dyed wool is investigated in terms of the CIELAB L*, a*, and b* parameters, and color-fastnesses to light, washing, and rubbing are tested according to iso standards. The mixture of dermorubin and 5-chlorodermorubin dyes wool orange-red with good color-fastness properties. Our procedure is equivalent to the industrial winch– technique. The results indicate that wool has a high uptake for the anthraquinone carboxylic acids. Apparently, the ionic bonds between the carboxylate ions of the dye and the protonated amino groups of the wool enhance the color-fastness properties of the dyed fabric. Dermorubin and 5-chlorodermorubin have significant potential as textile dyes, affording useful alternatives to synthetic dyes.
Naturally occurring anthraquinone pigments offer significant opportunities for dyeing textiles [6, 7]. Total synthesis of substituted anthraquinones is relatively cumbersome, frequently requiring toxic reagents, such as chromic acid or mercuric salts, and producing considerable amounts of toxic waste chemicals [1, 8, 11]. Further, in a large-scale production, purification of dyestuffs after synthesis is often difficult and expensive, and therefore optimizing the process with respect to yield and purity is necessary [11]. To avoid the disadvantages or deleterious effects of heavy synthetic processes, one should realize that nature is often the best synthesizer. In biosynthetic processes, enzymes act as catalysts, and no toxic side products or wastes are produced. Nature is rich in several types of pigments, such as anthraquinones, flavonoids, and carotenoids, and one has only to discover a suitable technique for isolating the pigments from the natural source of concern. The pure natural compounds can then be used as pigments straightforwardly or as raw materials modified further by chemical means to change their properties in the desired direction.
We were interested in the fungus Dermocybe sanguinea because we knew that it is rich in several stable anthraquinone colorants. In our previous articles, we described the dyeing of synthetic and natural textile fibers with the pure natural anthraquinone aglycones, emodin and dermocybin, using different dyeing techniques [6, 7]. Polyester and polyamide fabrics were dyed with emodin and dermocybin through high-temperature (HT) disperse dyeing, and the results were excellent. With the HT dyeing technique, uptake of emodin and dermocybin was nearly 100%. The color-fastness properties for polyester were eminently good, and for polyamide they were good. With the HT-method, no additional auxiliaries were used [6]. In the mordant dyeing experiments, wool and polyamide fabrics were dyed using KAl(SO^sub 4^)^sub 2^, K^sub 2^Cr^sub 2^O^sub 7^, CuSO^sub 4^, CoSO^sub 4^, as a mordant. These experiments showed that the pure natural hydroxyanthraquinones produced uniform dyeings with good color yields. Emodin and dermocybin yielded strong yellow, red, purple, and violet colors with a 1% owf dye solution. The color-fastness results of the mordant-dyed materials varied from good to moderate [7], but when the environmental aspects were taken into account, the disadvantages of mordant dyeing became obvious, even though minimum amounts of metal salts were used in dyebaths. The residual mordants ending up wastewater and their toxicological and carcinogenic risks were our major concern. Thus, we continued our search for more environmentally friendly dyeing techniques where no further auxiliaries would be needed.
In this paper, we describe the application of a mixture of dermorubin and 5-chlorodermorubin (2:1) as acid dyes for wool. In our previous experiments, anthraquinones were purified from the anthraquinone mixtures, fractions 1 and 2, using multiple liquid-liquid partition (mLLP) [2, 3]. Dermorubin and 5-chlorodermorubin were obtained as the main compounds from the separation of the anthraquinone carboxylic acids in fraction 2. They emerged from the tube train as a sharp main peak. As explained in our previous papers [2, 5], separating dermorubin and 5-chlorodermorubin from each other was extremely difficult because of their high aggregation tendency. However, our aim was to test the dyeing properties of anthraquinone carboxcylic acids, and because both dermorubin and 5-chlorodermorubin are carboxylic acids, their separation was not necessary. This enabled us to test the dyeing properties of a 2:1 mixture of dermorubin and 5-chlorodermorubin.
Emodin and skyrin come from fungi, which were cultivated on an appropriate culture medium [4]. Roth et al [4] used Penicilliopsis clavariaeformis Solms in their experiments, but they also mentioned some Dermocybe and Cortinarius species as potential fungi. Possibly in the future, someone will produce anthraquinone pigments suitable for dyeing textiles by cultivating fungi and extracting the pigments, which can then be modified further by chemical means. Toxic side-products from the industrial-scale syntheses could diminish when natural compounds are exploited as raw materials.
Bone mineral density-fracture risk
A commentary in the British Medical Journal that cites a meta-analysis by Deborah Marshall and colleagues highlights some of the problems with using bone mineral density measurements as the sole determinant for antiresorptive therapy. In the meta-analysis (British Medical Journal, 18 May 1996), the researchers analyzed eleven separate studies, published between 1985 and the end of 1994, which looked at bone mineral density measurements and their ability to predict fractures. The researchers also reviewed case control studies of hip fractures published between 1990 and 1994. After comparing the data, the researchers concluded: “Although bone mineral density measurements can predict fracture risk, they cannot identify individuals who will have a fracture, and a screening programme for osteoporosis cannot be recommended.”
In his BMJ Commentary, Professor Terence J. Wilkin (Plymouth Postgraduate Medical School, UK) questions the rising use of dual energy X-ray absorptiometry machines in the UK when bone density measurements “cannot identify individuals who will have a fracture.” He points out that recommendations for preventive treatment are based on the WHO’s definition of osteopenia that arbitrarily defines it as more than 1 standard deviation below the mean for premenopausal white women. Wilkin asserts that bone turnover, not bone density, should be the focus of antiresorptive treatment (hormone replacement and biphosphonate drugs). He says that the positive effect that these treatments have on preventing fracture cannot be attributed to the small gain in bone density that occurs. Since antiresorptive treatments work equally well in the elderly and the middle-aged, he suggests waiting until fractures are more likely to occur, ages 65-70, instead of starting treatment at menopause. He says that “frequency of impact, which rises exponentially with age, is the main risk factor for fracture.”
In response to Wilkin’s commentary, C. W. McGrother agrees that focusing on elderly people who show a specific risk is a good idea since antiresorptive treatments are expensive and have side effects. McGrother suggests using a fracture risk score based on factors such as bone mineral density, body sway, and muscle strength. Using these factors, T Nguyen and colleagues were able to identify “96% and 93% (sensitivities 88% and 81%) of men and women, respectively, who subsequently developed atraumatic fractures”.
DEVONSHIRE MINERAL COLLECTION of Chatsworth House: AN 18TH CENTURY SURVIVOR AND ITS RESTORATION
Assembled nearly 200 years ago, the mineral collection of one of English Society’s most remarkable woman has recently been reassembled and painstakingly restored to its original order. The collection, including additions made by her son, contains an impressive variety of classic 18th and 19th-century specimens, many of which carry fascinating stories now being revealed through historical research.
n 1992 the Russell Society celebrated its 20th anniversary. Since its creation from the mineralogical night classes of Bob King and Roger Harker, the society, named after that doyen of British mineral collectors Sir Arthur Russell (1878-1964), had risen to become the premier British society for the mineralogical amateur. The original Leicester-based society had spawned several semi-autonomous regional branches, each of which in turn would host the Annual General Meeting and Dinner weekend. On the 20th such occasion it was felt proper that the weekend be sponsored by the original Central Branch, and plans were made to keep the delegates happy. It is traditional for the host branch to arrange field trips to fruitful collecting sites but, these being few and far between in central England, and the majority of local members being well acquainted with those within easy distance, a novelty was sought that would stimulate wider interest. The weekend’s theme being “Collecting Minerals,” a visit to a local collection was in order, and visiting the mineral collection of the Duke of Devonshire at Chatsworth House was suggested by Franz Werner. No committee member had seen it, nor knew of its scope, but rumor had it that the collection was both extensive and historic. Past Dukes of Devonshire were well known as mine owners and supporters of the local mining and lapidary industries, and the present Duke was known to have purchased minerals at Sotheby’s auctions in the 1970’s.
Overtures were made to Chatsworth House and a positive, though guarded, response was quick to return. The author and society members Philip Jackson and Roy Starkey were sent to reconnoiter the collection and discuss the logistics of a mass visit. Phil arrived first; when we joined him he was holding a large prism of Russian aquamarine which he had just removed from a cardboard box of specimens, and he was looking, frankly, rather shell-shocked. We began opening a few more boxes. We were all astonished by what we found: first, another superb old-time Russian aquamarine crystal about 15 cm long, then a series of old Cornish specimens. A suite of superb Derbyshire galenas was to follow, along with many other local and foreign classics among a mass of rocks and ore samples. But our excitement was tempered with regret, as this was far from an organized collection. Specimens were stored in a basement cupboard in piles of cardboard boxes, others were jumbled in two late-18th-century glass-fronted cabinets on the floor above, and hundreds more filled a row of wall cases running the length of a nearby corridor (the “Cavendish Passage”). Decay and dilapidation were everywhere apparent. Dust and dirt and the ravages of pyrite disease had taken their toll; the bottoms of boxes were found-too late-to be home to loose number labels which could no longer be even tentatively assigned to the specimens from which they had fallen. Some pieces had labels held to them with perished rubber bands, notable mostly for their inaccuracy: one water-rolled galena pebble (probably from a Derbyshire cave deposit) was labeled “matlockite.” Specimens crumbled between our fingers, and brittle labels fell away as specimens were lifted from their yellowed newspaper wrapping.
Here was a fascinating and historic collection on the verge of extinction. Among Chatsworth’s wonderful heritage overall, a few rocks (no matter how exciting to us) had long been considered to be of little importance. One can hardly regard their lowly treatment as a failure of intent; it’s a matter of priorities. And yet despite the collection’s condition there was a feeling that it was somehow nearly all here, that little had actually been lost. Within the great house of Chatsworth little is ever actually thrown away-items may fade from view or pass from the memory of owners and staff, but somewhere they await eventual rediscovery. In a centuries-old house containing 175 rooms, 21 kitchens, 17 staircases and an infinity of nooks and crannies (see Duchess of Devonshire, 1982; 2002), there is plenty of space for a few rocks to hide.
The original catalogs of the collection, long unseen, had been rediscovered some years previously in an old box in the Estate Office and were produced for our inspection. The author’s name sprang from the title pages of these two volumes and an accompanying manuscript book inscribed Catalogue of the External Characters of Fossils. By White Watson F.L.S. Bakewell, Derbyshire. 1798. Watson was a pioneer of local geology, and a gifted lapidary; he was one of the most interesting figures in late 18th century Derbyshire geology. We were quickly able to match numbered specimens to entries in these 200-year-old handwritten volumes. Our excitement was palpable, and the receptive interest of Chatsworth staff in our enthusiasm was reassuring.
The Silver Vault at Chatsworth is home to two of the most remarkable pieces in the collection. From the outset, one of these two fine native silvers was obviously a fine silver wire from Kongsberg. It is over 25 cm long and curls like a plume of metallic smoke, still lustrous, from a mass of crystallized white calcite. The other is a thin sail-like triangular sheet of tarnished metal 19 cm high clasped at the base by a block of gray rock. This latter specimen, in common with a small group of other pieces we had put together during our initial arrangement, bore a label characteristic of those used by Henry Heuland: large paper squares with an off-center number in a bold hand. At the time we could go no further with this suspicion, but serendipity was to take us in hand. It had been our habit to use a photocopy of the original Watson catalogs on our working trips to Chatsworth House, but one day I neglected to bring them with me. Luckily, as it was a weekday trip, we were able to borrow the originals for the day, and while paging through one of them I discovered slipped in the back of one of them a previously un-noticed envelope entitled “old mineral labels.” Within were the brittle remains of a list written in French in Heuland’s characteristic hand. The list had been cut into strips, and parts had been lost, but enough remained to show it was a numbered description of ten specimens including two Kongsberg silvers, a Greenland tourmaline, a Saxony fluorite, a slab of rose quartz, and a German pyrargyrite. All of these pieces were instantly recognizable as those in the suspected Heuland suite! And all, with the exception of the silver wire, bore the same Heuland numbers as those on the list. The description of a silver wire on one fragment of paper left no doubt that here was the missing label for the second Silver Vault specimen: “Rameaux d’Argent natif d’un volume extraordinaire, supporté par une chaux carbonatée lamellaire; de la mine llsoë à Kongsberg en Norvège”-”A branch of native silver of an extraordinary size, supported by lamellar carbonate of lime . . .” Then deeply involved in writing a biography of Heuland (Cooper 2001), I was so excited by this discovery that I had to sit down to recover. This magnificent suite was dated by Heuland the 6th April 1820, and must have been a most costly purchase (though no prices are noted), but by whom? Presumably the 6th Duke, though we are yet to find confirmation of this. One day perhaps we will discover further evidence to explain both its existence at Chatsworth and the reason the labels were written in French!
As a result of the sale of his collection, some of Crichton’s specimens ended up in the collection of Isaac Walker (1794-1853) (Embrey, 1976; Embrey and Symes, 1987), which was later acquired by dealer James Gregory and sold piecemeal. F. N. A. Fleischmann purchased many of them and presented them to the BM(NH) along with a copy (perhaps Walker’s own) of the Crichton sale catalog. Other buyers included one Diana Maria Dondeswell (as noted in the part of the catalog of her collection in an annotated copy of Mawe’s A New descriptive catalogue of minerals … (1818) in the collection of Nick Carruth) and Sir George Tuthill (1722-1835), a graduate of the Freiberg Mining Academy. Tuthill’s large collection was bought by Francis Chantrey after Tuthill’s death. When Chantrey died a few years later, Heuland bought it from his widow and attempted to sell it entire to Prince Albert, but Queen Victoria intervened and prevented the purchase (Allingham, 1924). Heuland then sold it at auction, netting some 4 times the asking price for the whole collection. As a result, much of the collection then left the country. Many specimens ended up in Gerard Troost’s collection in America (Goldstein, 1984). Others appear to have been offered for sale in New York in 1846 “during the session of the American Naturalists the first week in September.” The specimens had been “purchased by a gentleman in London, long distinguished for his devotion to Mineralogy, by whom they were sent to a friend in this country” (Nick Carruth Collection). A further 250 specimens from the Crichton sale were acquired by the Leeds Literary and Philosophical Society, according to the Society’s Annual Report for 1826-27. One “Tourmaline on quartz with cleavelandite” from Catherineberg, Siberia was singled out for special mention. Some or all of these specimens may survive in Leeds Museum (Hancock et al., 1987), though only the tourmaline has been identified with certainty.
The Duke attended the Crichton sale, choosing the lots himself on the 4th and 7th of May (6th Duke’s diary for 1827, Chatsworth Archives). His choice may have been influenced by a fondness for things Russian, though it was not confined to Russian specimens. A manuscript list of the purchased lots survives at Chatsworth (see below). To identify them, the entries in the sale catalog were carefully cut out and pasted onto the specimens. Two weeks after the sale, on the 19th of May, Hart records a visit to Heuland, though no mention is made of further purchases.
By the mid-19th century the Devonshire mineral collections seem to have been long neglected. As early as 1844 the Duke comments in his Handbook: “All these minerals [i.e. his mother’s and his own] are in a disgraceful state of neglect and want of classification. Those collected by my Mother ought to be replaced in their former order, as they were in the days of White Watson of Bakewell, who in vain endeavored to hammer mineralogy into our youthful heads.” The present Dowager Duchess relates: “The cases of Georgiana’s minerals were [in the Mineral Room] when I first knew the house, and had to be passed when calling on Mr Thompson [the curator] in his lair. It was on one of these visits that Mr Thompson showed my sister Nancy the ‘diseased’ stones which had destroyed the paper they rested on and were beginning to eat into the wooden shelf. She was so struck by the idea of ill stones that she described them in one of her books.”
His passion for collecting was quick to surface, as was the almost genetic tendency for extending and refurbishing his remarkable portfolio of real estate: Chatsworth and the semi-derelict Lismore attracted much of this attention. Immediately after his succession he spent £50,000 on coins and medals, but soon tired of them, finding them insufficiently rewarding as collectibles. In 1844 he sold them at a huge loss for £7,056 to finance maintenance on his properties. He did, however, remain true to his love of books, though claiming that a lack of learning made him unworthy of his own collection. This too was a family trait: his father had been a great bibliophile and reader, Georgiana delighted in books, and her brother the 2nd Earl Spencer has been described as “the greatest collector of incunabula and early printed books who has ever lived” (Lees-Milne, 1991). Hart bought expansively at many of the greatest book sales of the 19th century. When he brought his books together at Chatsworth he found the existing library too small to accommodate them and had the 1st Duke’s Long Gallery gutted to take bookshelves, incidentally weakening the structure of the house through the injudicious modifications. This architectural disaster aside, the present library is a fine space and makes a lasting impression on today’s visitor, being opulent and grand, yet still attractively domestic. The Chatsworth Library now contains over 50,000 volumes.
In London in 1816 Hart met the Grand Duke Nicholas of Russia, destined to become the Tsar of All the Russias. The two young men struck up an immediate, deep and lasting friendship. The Duke invited Nicholas to Chatsworth and the invitation was immediately accepted. For a few days they toured, shot, and talked together into the night, enjoying a care-free relationship that was often to be recalled but never to be repeated as the constraints of state and status tightened around them both with the passing of the years. Nicholas returned to London, and the Duke followed his new friend in early 1817. They did the social round and dined together frequently. When Nicholas left England to return home to his bride-to-be, he invited Hart along. The two traveled separately, but met up often en route. Hart stayed for several weeks in St. Petersburg and was much struck by the beauty of the city. He dined with the Emperor Alexander I and was feted by the Russian nobility. After the royal wedding he traveled back to England via Italy and France and thence to Chatsworth. In 1818 he was setting to at Chatsworth with great determination. The architect Jeffry Wyatt (later Sir Jeffry Wyatville), fresh from his successes at Longleat, was called in, and together they planned a formidable extension to the house to accommodate Hart’s collections and his intentions for grand entertainments. Wyatt also compensated for the architectural failings of the library.
News from the Keweenaw: part 2: recent mineral finds in Michigan’s Copper Country: seventh in a series of articles on the mines and minerals of Michigan’s Copper Country
As the first article stated, the future looked bright for additional specimen recovery, and it has been. Four big finds were made in the Keweenaw, along with numerous smaller ones. The four most exciting were the discovery of (1) arborescent copper crystal groups cached at the Central mine town site, (2) copper crystals recovered from Lake Superior at the Gull Rock fissure vein, (3) hundreds of copper crystals from the Indiana mine, and (4) more than two hundred specimens of analcime/calcite crystal groups from the Rhode Island mine. This article describes these and other finds made from 1998 through the 2002 collecting season. The localities are arranged geographically, starting with Keweenaw Point and continuing in a southwestern direction to the White Pine mine at the southern end of the district.
he waters off Keweenaw Point have drawn much attention since the publication of the first “News from the Keweenaw” article that described the occurrence of yellow datolite at the bottom of Lake Superior. Many mineral-collectors-turned-scuba-divers, or vice versa, have worked the icy waters with mixed success. On a boat trip to the area in August 2000, I observed telltale air bubbles rising to the surface from the air tanks of at least five divers who were scouring the bottom of the lake for datolite nodules and agates–it resembled a frogmen scene in a World War II movie.
Bob Barron, an accomplished scuba diver and mineral collector, has had good success in locating and recovering datolite from the lake bottom. To date, he has discovered two areas between Keweenaw Point and Manitou Island where datolite occurs in fissure veins. The first is in 30 feet of water about 1,000 feet offshore from Keweenaw Point. Here, a narrow datolite vein in vesicular basalt, which has a strike of N. 45[degrees] W., split into several smaller veins and formed a zone about 18 inches wide and 10 feet long. Datolite nodules to 8 cm in diameter were recovered from this zone; they have a whitish-brown chalky rind, making them easy to spot in the water. Most of the nodules are fracture free and range in color from translucent mustard-yellow to olive-yellow. The other predominate color is a reddish-brown to orange-red. About seventy datolites of varying sizes have been found at this spot.
Closer to shore, and in only 10 feet of water, datolite nodules were discovered in August 2001 in a fissure vein that trends S. 75[degrees] E. and consists of quartz, calcite, and laumontite. The productive zone along the vein was 20-180 yards out into the lake. The color of most of the datolite from this vein is a dark red to maroon-brown, quite different from that in the zone previously described. Most of the datolites show a certain amount of fracturing, but this only enhances their overall beauty. The action of the lake water over thousands of years has formed a white altered zone around their rims and adjacent to both sides of the fractures. About thirty superb datolite nodules have been recovered from the vein so far.
Point prospect, located about 6 miles southeast of Copper Harbor, has produced some of the largest copper crystals found in the Copper Country (Rosemeyer and Carlson 2000). In summer and fall 2001 the locality was reworked by local collectors, and a number of coarsely crystalline copper specimens weighing up to 40 pounds were recovered from the south end of the trench on the fissure vein. A few of the copper pieces had vugs to 1 cm in diameter that contained beautiful reticulated groups of elongated microcrystals of dark red cuprite. Rumor has it that another vein in the general vicinity was discovered in summer 2001 and may have produced crystals similar to those found in the Point prospect vein.
Yes, there are thunder eggs in the Copper Country. The first mention of them was in 1955, when Cornwall, in his description of the bedrock geology of the Fort Wilkins quadrangle, noted the presence of lithophysae and spherulites in intrusive rhyolites in the Fish Cove area. He further stated that the lithophysae are lined with orthoclase and quartz, and the cavities are partially filled with calcite, quartz, and chlorite.
A more recent discovery of these thunder eggs was made by Ken and Jim Flood in June 1998 while exploring the south side of the Keweenaw Peninsula by boat. The thunder eggs were found at the east end of Fish Cove in shallow water along the shoreline where the intrusive rhyolite crops out. Collecting the thunder eggs–about one hundred in all–was done by scuba diving off the rhyolite outcrop. They range in size from 4 to 14 cm in diameter. Most all are water worn, distorted, and flattened, but a few are nearly round, and their surfaces show distinctive raised ribs that form polygons. Their interiors are filled with crystallized clear, smoky, and amethystine quartz and calcite. Only a small number of the thunder eggs show concentric agate banding.
In Memoriam - Jean Petermann Kemp Zimmerman, mineralogical museum curator, mineral collector Carl Krotki and gemologist Richard T. Liddicoat - Obituary
Jean Petermann Kemp Zimmer, the fourth curator of Michigan Technological University’s A. E. Seaman Mineral Museum, passed away on 29 December 2001. She was eighty-four years old. Much of the success and growth that the museum enjoys today is based on the strong foundation that Jean laid.
Jean was born on 24 December 1917 to Philip E. and Myrna (Moss) Petermann. Her family figures prominently in the history of Michigan’s Lake Superior copper district. Her grand-father, Col. John P. Petermann, served in the Spanish-American War and became a successful merchant, opening stores in Allouez, Gay, Kearsarge, Mohawk, and Phoenix. Her great uncle, Albert E. Petermann, was an attorney with, and later president of, the district’s largest mining company, the Calumet and Hecla. He served on the Michigan College of Mining and Technology’s (MCMT) Board of Control from 1927 to 1944.
Jean enrolled in MCMT in 1935 as one of a handful of female students in an approximately eight-hundred-man student body. She studied mineralogy and geology under Prof. Wyllys A. Seaman (son of museum founder A. E. Seaman) and Prof. Kiril Spiroff. She graduated with honors in 1939, with a bachelor of science degree in geology, and was awarded the Geology Key, the top departmental academic award. In 1940, she received her master’s degree in geology from the University of Michigan. She taught mineralogy in the MCMT Department of Geology from 1940 to 1943 but, more importantly for her career, assisted Spiroff in curating the A. E. Seaman Mineral Museum collection. Jean then left the area, returning in 1967 to serve as Spiroff’s assistant and succeeding him as curator in 1975.
Jean’s curatorial style favored collection protection, preservation, and management. Although not a collection builder in the style of a Paul Desautels, she was the right person at the right time for the A. E. Seaman Mineral Museum. Almost single-handedly, she protected the museum collection during a vulnerable period in its history, ensuring that there would be a collection and museum to serve a future audience.
In 1972 Jean was confronted with the impending demolition of the museum’s existing home in the 1930s-vintage Hotchkiss Hall and the packing, storing, and reinstalling of a more than forty-thousand-specimen mineral collection in a more contemporary facility. Whenever an institutional mineral collection is taken off display and put into storage, it is most susceptible to intrusion and even elimination–”out of sight, out of mind.” Jean understood this and zealously kept the collection and its relevance in front of Michigan Tech administrators and planners.
She quickly organized and supervised a select team of student aides to pack the collection. Included were Marc L. Wilson, now head of the Section of Minerals of the Carnegie Museum of Natural History, and Dr. Theodore J. Bornhorst, Michigan Tech’s current chairman of the Department of Geological and Mining Engineering and Sciences. It is my understanding that few–if any–specimens were damaged during the packing process. The collection was stored in a basement room of the Michigan Tech Library from 1973 to 1976, and during that period Jean hand-catalogued well over twenty-five-thousand specimens, writing entries into bound ledgers with a triple-zero Rapidograph drafting pen.
As a break from cataloguing, Jean carved out time to design much of the planned museum facility, slated for the fifth floor of the “new” Electrical Energy Resources Center. She picked the interior colors, designed new exhibit cases that optimized specimen viewing and display, planned the display case arrangement and the exhibits that the cases would contain, and personally installed at least 50 percent of those displays. She made the first serious attempt in the museum’s history to create aesthetically pleasing displays, lightening the specimen density and grouping specimens to highlight color and texture.
Her natural preservation and collection management abilities didn’t impede Jean from acquiring specimens for the museum’s collection. Like most curators, she was thrilled to purchase fine specimens whenever funds were available, and she tried to keep up with what was current on the specimen market. I recall with nostalgia her excitement at acquiring in the 1970s one of the “new” Tsumeb dioptases from Prosper Williams at the Greater Detroit Gem and Mineral Show.
Jean thoroughly enjoyed attending the Detroit and Tucson Shows and basked in the camaraderie afforded by the mineralogical community. Some of her fondest career memories included participating in the first Mineral Museums Advisory Council meetings. She relished the company of mineral museum curators and was quite proud to be one. She took special delight in the panel discussions that included such luminaries as Paul Desautels, Clifford Frondel, Peter Embrey, and Joseph Mandarino.
Jean took a personal interest in the museum’s donors. She was a close friend of Hazel E. Robbe, who donated the George B. Robbe collection in the 1960s, and Joyce Burchenal, who purchased an assortment of fine specimens for the museum’s collection in the late 1970s and early 1980s. She cultivated museum visitors such as Prof. E. W. Heinrich and Donald C. Gabriel, and it was her courtesy and kindness that laid the groundwork for their major gifts to the museum.
Carl Krotki was born in Salt Lake City in 1914. Carl’s uncle, Max Krotki, owner of the Krotki Iron Mines, sparked the young Carl’s interest in minerals with pyrite crystals. Following the death of my grandfather in 1923, the family moved to New York City, where Carl attended James Monroe High School and met the great love of his life, my mother, Shirley, to whom he was married for sixty-one years until her death in September 2000. After earning a degree in accounting from the City College of New York and becoming a CPA, Carl served in the Navy during World War II. After the war, he earned a doctorate in jurisprudence from the Brooklyn Law School. In the late 1960s my father’s major client induced him to sell his accounting practice and become controller for Permag Corporation, a major manufacturer of permanent magnets that grew to have nine branches around the country. The strategic placement of Permag facilities made it possible for my father to be within striking distance of almost any mineral meeting in the country.
In the late 1950s, my brother Saul brought home rocks from a nearby highway dig and asked my father to identify them. That led to trips to the American Museum of Natural History, to the purchase of some field guides, to a lifelong hobby. In 1958 Carl joined the New York Mineralogical Club and was elected its treasurer, an office he held for more than fifteen years. He was also the president of the New York Gem and Lapidary Society.
Eventually, my father’s interest in minerals took a new turn: He became interested in antique books on minerals and gems, especially those with colored plates, in this field his mentor was his, beloved friend Neal Yedlin. My father was an eager pupil–he read about books, spent hours in the New York Public Library and in Neal’s library, and studied auction catalogs from all over Europe and the Americas, taking meticulous notes. It became commonplace for him to come home dirty, not with the mud of a quarry but with the dust of an old book barn. In bookstores around New York he was known as Mr. Mineral. By the mid-1970s my father’s library was acclaimed one of the four or five most complete assemblages in the country. Interested in sharing historical mineralogical data, he developed several slide shows on mineralogical literature and gave talks at federation shows and at local club meetings along the eastern seaboard from Boston to Washington. A great storyteller with a ready smile and a wonderful sense of humor, Dad was a real audience pleaser. The Carl Krotki Library of Gemology and Minerology, consisting of more than fifteen hundred volumes, was auctioned at the Swann Galleries in New York on 8 December 1994. It was the largest private mineral library ever to come up for sale, attracting bidders from around the world.
My father passed away on 17 July 2002 in his apartment in New York City. I am struck now remembering the good times the mineral collectors had whenever they got together. United by a common love, they explored and continuously found new aspects of the mineral world to keep them fascinated. Their passion transcended religion, politics, and the economy. The world of mineralogy enriched my father’s life in many ways but most especially in giving him the two most important friendships of his life: those of Neal Yedlin and Edge Goldstein, men he loved more than brothers, and, in closing this remembrance of my father, I remember them too.
Achieving improvement through nursing home quality measurement
CMS covers almost 40 million people with Medicare. Over the years, CMS’s role has evolved from that primarily of claims administrator to one of insurer and information resource for the beneficiaries covered under the Medicare and Medicaid Programs. A key challenge in that evolution is effective communication of the quality of Medicare services provided under the program in terms that beneficiaries can understand.
In this article, we describe CMS’s initiative to use nursing home performance measurement as a tool to share information on the quality of care provided in nursing homes for beneficiaries and their families. The article emphasizes the evolution of performance measurement in nursing homes and recent efforts by CMS to develop new measures. We also describe a major CMS pilot project to test the feasibility and effectiveness of the new communications program for beneficiary choice and quality improvement. We conclude with a discussion of the key challenges facing the pilot and national NHQI.
CMS has launched several new initiatives to improve its communications with Medicare beneficiaries. The “Helping You Help Yourself” media campaign is a multi-million dollar effort to help Medicare beneficiaries and their families utilize Medicare’s information resources more effectively; to get help with questions, recognize their options, and better understand Medicare coverage policies. This campaign makes use of bilingual television, radio, and newspaper advertisements as well as use of the Internet to reach the diverse population of Medicare beneficiaries.
CMS also publishes an annual handbook, Medicare & You, which is mailed to every beneficiary household each fall, and to new enrollees each month. It is available in Spanish, Braille, audiocassette.he handbook provides basic information on Medicare enrollment, covered services, cost sharing, fights and protections, and health care choices for receiving Medicare benefits.
CMS also runs a 24-hour call center that can be reached at 1-800-MEDICARE. Approximately 15,000 individuals call in each week with questions about their Medicare coverage, requests for personalized material, and for guidance about choosing a health care provider.
Nursing Home Compare includes resident characteristics, State survey deficiency data, and facility characteristics such as bed size and ownership. This information is helpful in drawing a picture of the types of individuals residing in the home. Information on the resident characteristics is drawn from two main data sources: five of these resident characteristics (dependency in eating, bedfast, contractures, unplanned weight gain or loss, and inappropriate behavior) are derived from information collected by each State’s survey and certification team during their annual surveys of all Medicare and Medicaid certified facilities. Another set of three resident characteristics (incontinence, physical restraints, and pressure [bed] sores) is derived from the Minimum Data Set (MDS), an assessment instrument developed for the purpose of patient assessment and care planning. The MDS-based data have been published on the Web site since 2000.
Beginning in fall 2002, CMS plans to enhance the Nursing Home Compare Web site by publishing a much broader array of quality measures characterizing the performance of nursing home facilities across the Nation. To prepare for the national release, CMS is sponsoring a pilot demonstration in six States to assess the value of these measures as a tool to assist consumers in their decision process as well as an instrument for enhancing quality improvement. This pilot, which began in April 2002, will test new communication mechanisms for reaching Medicare beneficiaries that will not only inform the national release later this year, but potentially provide the template for public reporting initiatives in home health and hospital care as well. The following section provides a background on the development of quality measures for consumer information and quality improvement, with specific reference to the nursing home industry.
In 1987, Congress passed the Omnibus Budget Reconciliation Act which required that the U.S. Department of Health and Human Services (DHHS) develop and implement a comprehensive patient assessment tool which would collect uniform patient information on all nursing home residents and could be used to assist in patient care planning. The resulting instrument was the MDS, a clinical data set that includes over 400 items measuring a variety of functional, behavioral, social and clinical aspects of nursing home residents (Morris et al., 1990). Nationwide collection of the MDS began in the 1990s. All Medicare and Medicaid certified nursing facilities are required to fill out a MDS at least every 3 months for every resident living in the nursing home and more frequently for recent admissions. These assessments are transmitted to CMS through the State and, since June 1998, have served as the basis for the prospective payment system for all Medicare related charges and some State’s Medicaid reimbursements to certified nursing homes.
The nursing home QIs are also used by a number of nursing facilities to identify their own care problems and conduct internal quality improvement programs to correct any weak processes or poor outcomes before they become serious and widespread. In fact, several State governments, industry groups, and research organizations have developed various software and reporting protocols that use facility QI scores to educate and guide a facility in how to focus its energies in terms of improving patient care outcomes. The Medicare quality improvement organizations (formerly known as the peer review organizations) in several States have utilized a variety of MDS-based QIs, not just limited to those developed by the CHSRA team, to engage the industry in quality improvement projects on such topics as pressure ulcer treatment. This type of provider accountability–having providers proactively use quality measures to identify quality concerns and improve care practices–is a major goal of CMS’s performance measurement program.
As described earlier, CMS posts a select number of these QIs on its Medicare.gov Internet tool called “Nursing Home Compare.” This site is available to all consumers, providers, and industry groups and allows individuals to look at the performance of all Medicare-certified nursing homes on specific QIs such as the prevalence of incontinence, pressure sores, and the use of physical restraints. The Web site language describes each of these measures, explains their importance and recommends that people use this information in combination with onsite visits to help make more informed decisions about their care. The Web site also allows consumers to compare individual facilities to one another as well as to the State and national averages for each of these performance measures. The nursing home specific QIs can be downloaded directly from the Web site. Nursing Home Compare is the most frequently visited quality Web site at CMS, accounting for close to 500,000 visits monthly.
Several States have begun reporting the MDS-based nursing home QIs on their own Web sites and publication vehicles. Wright et al. (2002) found that 20 States, as well as 9 non-government sites, currently provide access to information on quality of care in nursing homes. These sites vary from providing information about the facility and the characteristics of its residents to information on deficiencies identified during State survey and certification inspections. Two of these States (Maryland and Florida) already use the CHSRA QIs on a facility specific basis to inform the public on nursing home quality of care (Wright et al., 2002). Other States, such as California, Rhode Island, and Ohio are in the process of developing reporting systems that use MDS-based QIs.
The proliferation of nursing home QIs has demonstrated that broad interest exists among States and consumers in the publication of these data. However, the limitations in the measures have called for improvements in the QIs to enhance their utility as performance measures for comparing and rating performance at the provider-specific level.
Neutron Radiography Measurements of Moisture Distribution in Multilayer Clothing Systems
Neutron radiography is used to study moisture transport in textiles for the first time. A selection of clothing systems composed of layers with differing water transport properties is studied to demonstrate the feasibility of using the technique. The results are compared to the weights of the individual layers obtained during separate sets of measurements in the same horizontal configuration, as well as in a vertical configuration on a heated cylinder. The results of the three measurement approaches agree with respect to layerwise moisture distribution in the different textile combinations, and the radiography data provide a lateral visualization of the distributions. A decisive role in fluid water transport is revealed for the innermost two textile layers.
For physically active workers and athletes, the transport of liquid perspiration in clothing systems is quite important. Only by evaporation of liquids can the body efficiently cool itself at high physical loads, which has served as a primary motivation for the increasing interest in the transport of liquids through clothing systems. Indeed, keeping the skin dry after physical activity by rapid transport of liquid perspiration away from the skin was often an important goal for clothing designers, due to the role of humidity next to the skin in determining comfort levels [11]. To quantify the factors influencing this property in clothing systems, a number of methods have been developed to measure water vapor transport
Increasing attention has been given to the question of how liquid perspiration is transported through textile systems, and where it evaporates, thereby exerting its cooling power. Methods used to measure water sorption of single textile layers have been reviewed, e.g., in reference 12. Several studies have examined the relative rates of liquid and vapor moisture transport through textile systems [10, 1,2, 4, 24]. Wicking of liquid moisture between fabric layers was also studied by several groups [23, 3, 1]. All concluded that such interlayer wicking depends on having a minimum amount of water in the “donor” layer, the amount being dependent on several parameters. The most recent work concluded that the pore sizes in the layers and their corresponding volumes are important determining factors [3], Besides the amount of water contained in the donor layer, the pressure applied on the fabric layers is an important external factor to be considered [19].
Since the treatment of heat and water vapor transport through multilayer clothing systems in reference 7, computational models have been developed to describe such processes at unprecendented levels. Advances in realistic handling of the presence of liquid moisture in a complex textile assembly have been reviewed, e.g., in publications of the most recent examples [6, 8, 17, 18]. Thus, there are increasing computational incentives to obtain detailed experimental data on moisture transport dynamics in complex textile assemblies.
Experimental determinations of the location of moisture in a multilayer clothing system are still largely limited to gravimetric methods, e.g., weighing the individual layers of a multilayer system during the study. A problem with this approach observed in our laboratory is that the results often suffer from sizeable moisture losses in the weighing process, because the ambient atmosphere interacts with the exposed interlayer volumes and layer surfaces of the clothing system. The method also clearly limits the dynamics that are accessible to study, especially the space- and time-dependence of moisture distribution within a textile layer. One approach to this problem is magnetic resonance imaging [16], which, quantitatively and without altering the sample, can rapidly monitor the internal moisture distribution of textile assemblies. This method has great potential, but has been applied to only a limited number of systems [13]. Neutron radiography [21, 20] has a similar potential for studying such systems. Since neutrons are scattered strongly by hydrogen, water is particularly easily detected.
We present the first study comparing neutron radiography and gravimetric measurements for multilayer textile systems. Our study clearly demonstrates the ability of neutron radiography to provide a visualization of moisture distribution in a system without invasive probing of the individual layers. We also reveal the important role of the innermost two layers of the textile combinations studied here in the transport of liquid moisture from the skin.
A perspiring, heated cylinder was also used to characterize the textile systems. This cylinder is made of aluminum, with a diameter of 10 cm and length of 30 cm, mounted standing on one end in a climate chamber held at 20°C and 30% RII, in wind maintained at 1 meter/second. It has several water outlets, controlled by the same principle as described above. To continuously monitor perspiration-induced weight changes in the system, the apparatus was placed on a precision, computer-interfaced balance, measurements from which could be compared to the amount of perspiration water supplied to the system to yield the mass of moisture trapped in the clothing system at a given time. Four-layer systems, in this case consisting of samples of the same materials sized to match the cylinder, were wrapped around the apparatus, than the surface temperature of the cylinder was stabilized at 35°C by the control electronics. After stabilization for 1 hour, the heating power was held constant at a value roughly comparable to typical human values under strong exertion (350 W for the entire body), and the perspiration rate at 1 l/person-hour, or 7.5 g for 13 minutes. The individual layers were also weighed before and after measurement to determine the moisture distribution.
The radiography measurements were made at an ambient temperature of 23° C and relative humidity of 30%, the conditions in the neutron radiography facility. The characteristics of this facility are described elsewhere [14, 15], as are the basic principles of applying neutron radiography to textiles [21]. The samples were mounted on the same apparatus as for the horizontal gravimetric measurements. The collimated neutron beam was directed at the samples across the width of the layers, i.e., from the reader’s point of view of Figure 1. The transmitted neutrons were detected with a cco-camera imaging system [22] as an array of 1024 × 1024 pixels with a dynamic range of 16 bits. The measurements were obtained as a continual series of images collected during a perspiration sequence corresponding to that of the gravimetric measurements, i.e., for 13 minutes, after acclimatization in the neutron facility and several minutes after being placed on the sample holder. An image of the dry sample just before the onset of perspiration served as reference. see the discussion below for further details.