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PubMed1987

Differences in central and peripheral neural actions between soman and diisopropyl fluorophosphate, organophosphorus inhibitors of acetylcholinesterase.

Toxic doses of acetylcholinesterase (AChE) inhibitors produce prominent motor symptoms (fasciculations, fibrillations, and body tremors) and muscle fiber necrosis. The severity and quality of motor symptoms and fiber necrosis depend upon the specific AChE inhibitor. To examine the importance of nerve and muscle activity in producing muscle necrosis, we recorded electromyographic activity from normal and acutely denervated rat gastrocnemius muscle following administration of the organophosphorus AChE inhibitors soman and diisopropyl fluorophosphate (DFP). The motor symptoms induced on the denervated side represented activity originating at the nerve terminal while those of the contralateral nondenervated muscle represented the sum of peripheral plus central descending activity. The results indicate that soman and DFP produce different responses. At nonlethal toxic doses, the majority of motor symptoms induced by soman is due to impulses descending from the central nervous system, and a proportion of these symptoms are epileptiform activity. This activity is not generated at spinal levels. In contrast, DFP produces motor symptoms mainly by peripheral action that is dependent on a functioning nerve terminal. At lethal doses, both agents have central and peripheral effects. Different patterns of electrical activity are associated with each of the motor symptoms. We found that muscle fiber necrosis correlates best with peripherally generated high-frequency repetitive discharges.

Acetylcholinesterase↗
PubMed2006

High-power laser with Nd:YAG single-crystal fiber grown by the micro-pulling-down technique.

We present optical characterization and laser results achieved with single-crystal fibers directly grown by the micro-pulling-down technique. We investigate the spectroscopic and optical quality of the fiber, and we present the first laser results. We achieved a cw laser power of 10 W at 1064 nm for an incident pump power of 60 W at 808 nm and 360 kW peak power for 12 ns pulses at 1 kHz in the Q-switched regime. It is, to the best of our knowledge, the highest laser power ever achieved with directly grown single-crystal fibers.

Journal Article↗
PubMed1991

Acquired perforating dermatosis. Transepidermal elimination of DNA material and possible role of leukocytes in pathogenesis.

A patient had acquired perforating dermatosis and suffered from renal disease, diabetes mellitus, and lupus vulgaris. Histologic and immunohistochemical studies revealed that the bulk of the coarse granular basophilic material being extruded by transepidermal elimination was of nuclear origin obviously derived from polymorphonuclear leukocytes that were particularly abundant in an early, nonperforated lesion. At the lower boundary of the material being eliminated transepidermally, leukocytes were seen to accumulate, to undergo pyknosis and karyorrhexis, and to transform into nuclear debris. As a minor component, the material contained collagen fibers with altered staining qualities and, in an early lesion, elastic fibers. We speculate that accumulation, disintegration, and enzyme release from polymorphonuclear leukocytes may represent an important, hitherto disregarded driving force in transepidermal elimination. Lysosomal enzymes may later be responsible for the alteration of staining properties in collagen fibers, the degradation of elastic fibers, and for opening up the transepidermal route by impairing intercellular keratinocyte cohesion.

Aged↗
PubMed1995

[Biochemical and morphological studies on soft tissues in hip osteoarthrosis].

To investigate the pathogenesis of osteoarthrosis, we have performed biochemical and morphological studies, other than roentgenological examination, on the soft tissues. Biochemical analyses of collagen were performed on muscles (gluteus medius) in normal and in pathological cases. In the terminal stage of osteoarthrosis, we observed more immature collagen fibers in muscles, than in normal cases. In the preosteoarthrosis stage, immature collagen formation was inconsistent with various degrees of immaturity observed. Morphologically, irregularity in the muscle fibers and interfascicular-fibrosis was observed in the gluteus medius only at the terminal stage but not at the preosteoarthrosis stage. In some cases, we observed a predominance and/or grouping of type 1 fibers. Among the 20 cases with preosteoarthrosis, 3 cases (15%) showed marked biochemical changes in both quantity and quality of collagen fibers in the gluteus medius, as compared with cases at the terminal stage. These findings may be valuable in studying the onset and development of the pathophysiology of osteoarthrosis.

Adolescent↗
PubMed1987

Nutritional evaluation of roasted, flaked and popped A. caudatus.

A study was carried out with a selection of A. caudatus CAC-064, which was processed in three different forms: popped, flaked and roasted. The popped sample was prepared by subjecting the grains to a temperature between 175 and 195 degrees C for 15-25 seconds. The flaked sample was obtained by adjusting moisture content to 26% and using heated (200 degrees C) rotating drums for a contact time of 1-3 seconds, and roasting was achieved by heating the grain at 150 degrees C for a lapse of 60-90 seconds. All samples, including a raw sample, were analyzed for proximate chemical composition, minerals, available lysine and tryptophan content, as well as damaged starch, calories, soluble and insoluble fiber, and protein quality. Differences in chemical composition due to the processing applied were small and insignificant, except for lower available lysine values, and insoluble fiber with higher values in the roasted sample than in the flaked and popped samples. Likewise, the roasted sample had higher levels of damaged starch. Protein quality was highest in the popped sample (NPR 3.19), followed by the flaked (NPR 2.78), the roasted (NPR 2.24) and the raw (NPR 1.73) samples. These values were related to available lysine. Protein digestibility was lowest in the roasted material followed by the flaked and the popped products. It is concluded that establishment of optimum processing conditions is necessary in order to achieve maximum utilization of amaranth grain.

Amaranthus↗
PubMed1988

Response properties of fibers in the hamster superior laryngeal nerve.

The purpose of the present investigation was to record electrophysiological responses from single fibers in the hamster superior laryngeal nerve (SLN) that were responsive to chemical stimulation of the larynx. Twenty chemical solutions, commonly used in studies of mammalian gustatory physiology, were applied to taste buds on and around the epiglottis. These stimuli were dissolved in physiological saline. Responses were the number of impulses elicited over a 15-s period following stimulus onset, above or below the background activity elicited by a previous rinse with saline. Unlike fibers in the hamster chorda tympani or glossopharyngeal nerves, SLN units were not easily classifiable into response types. Excitatory stimuli were primarily acids and bitter-tasting stimuli, with the order of their effectiveness being urea much greater than tartaric acid greater than HCl greater than KCl greater than citric acid greater than caffeine greater than quinine hydrochloride greater than acetic acid. The sweet-tasting stimuli and most salts other than KCl were primarily inhibitory, with the order of inhibitory effectiveness being CaCl2 greater than sucrose greater than fructose greater than LiCl greater than NaNO3 greater than Li2SO4 greater than NaCl. A hierarchical cluster analysis of fibers yielded no distinct clusters, yet differing sensitivities across the fibers were suggested. SLN fibers are highly responsive to sour and bitter stimuli, although they are not sensitive to fine differences in taste quality, as are fibers in other gustatory nerves.

Action Potentials↗
PubMed2006

Basal metabolic rate and organ size in Brandt's voles (Lasiopodomys brandtii): Effects of photoperiod, temperature and diet quality.

This study examined the effects of photoperiod (long day [16 Light:8 Dark] and short day [8 Light:16 Dark]), temperature (cold [5 degrees C] and warm [23 degrees C]), and diet quality (high-fiber diet [36% neutral-detergent fiber (NDF)] and low-fiber diet [23% NDF]) on basal metabolic rate (BMR), digestible energy intake, and organ size in the Brandt's vole (Lasiopodomys brandtii). Cold increased BMR and showed a significant interaction with diet quality. Cold and short photoperiod increased intake of food and digestible energy. The high-fiber diet increased food intake, but decreased digestibility, and had no effects on digestible energy intake. Voles housed in the cold had heavier liver, kidneys and gastrointestinal segments but a lighter carcass. Segments of the gastrointestinal tract tended to be heavier when voles were fed the high-fiber diet. Voles housed in short photoperiod had lighter heart and kidneys but heavier gut segments. With the effects of body mass on BMR and organs was removed, BMR was significantly related to the dry mass of heart, liver, kidneys and cecum. Digestible energy intake was significantly related to the dry mass of kidneys and stomach. These significant relationships were also detected after removing the effects of body mass, temperature, photoperiod and diet quality. There was also a significant correlation between BMR and digestible energy intake. Our results suggest that variations in BMR reflected the evolution of metabolic machinery that induces higher energy intakes. The data also support the assimilation capacity model of endothermy.

Animals↗
PubMed1983

Effects of dietary fiber on mucosal growth and cell proliferation in the small intestine of the rat: a comparison of oat bran, pectin, and guar with total fiber deprivation.

The effects of dietary fiber on small intestinal mucosal mass, morphology, and cytokinetics were studied by feeding three qualitatively different forms of fiber to 40 rats for 4 wk. A fiber-free diet was fed to the control group and a similar diet with either a 20% oat bran, 10% pectin, or 10% guar supplement to the other three groups. All groups of rats exhibited similar caloric intakes and weight gains. Only the guar diet produced a significant increase in mucosal mass, as demonstrated by 19.1% increase in mucosal weight (p less than 0.05), a 16.7% increase in RNA (p less than 0.05) and an increase in DNA from 38.3 +/- 1.8 (SEM) to 44.6 +/- 2.3 micrograms/cm intestine/100 g body weight (p less than 0.05) when compared to the controls. The pectin-diet produced a decrease in villus height from 102.1 +/- 2.4 to 94.3 +/- 2.4 cells but an increase in crypt column length from 25.3 +/- 0.6 to 27.4 +/- 0.4 cells when compared to the controls (p less than 0.05). The shift in labeling index distribution curves for pectin and guar to the right and for oat bran to the left indicated an increase and decrease respectively in labeling index. The higher rate of epithelial cell migration in the pectin- and guar-fed groups shortened their estimated villus cell transit times to 36.4 +/- 0.7 and 37.0 +/- 1.4 h, respectively, when compared with 42.6 +/- 1.2 h in the oat bran and 41.1 +/- 1.0 h in the control (p less than 0.05). These results show that the modulation of small intestinal mucosal structure and growth by dietary fiber appears to be mediated through alterations in cell proliferation and that these changes depend not only on the quantity but also the quality of the fiber present in the diet.

Animals↗
PubMed2005

A novel approach to prepare extended DNA fibers in plants.

BACKGROUND: The extended DNA fiber preparation procedure is still imperfect in plants due to the existence of a hard cell wall; thus, high quality of extended DNA fibers for fluorescence in situ hybridization (FISH) analysis is often difficult to be obtained rapidly and efficiently. In this study we have developed a fast and widely effective method to prepare DNA fibers from various plant species and the fibers are suitable for fiber FISH mapping. METHODS: Fresh young leaves were chopped with a sharp sterile scalpel in a Petri dish that contained ice-cold nucleus isolation buffer followed by filtration through 33-mum nylon mesh. Nuclei were obtained by centrifuging the filtrates at high speed (16,000g) for 40 s. Nucleus lysis buffer (0.5% sodium dodecylsulfate, 5 mM ethylenediaminetetraacetic acid, 100 mM Tris, pH7.0) was added to nuclei on slides, and DNA fibers were dragged and extended with a clean coverslip. RESULTS: The key of this method is that liquid nitrogen grinding of leaves is replaced by chopping with a blade in ice-cold nucleus isolation buffer. With the liquid nitrogen method, over- or under-grinding of leaves occurs more frequently, and DNA fibers with the desired quality are not obtained easily. In contrast, it is easier to release nuclei from cells in nucleus isolation buffer by chopping, which results in fewer nuclei being destroyed. Highly extended, intact, and long DNA fibers can be generated to a great probability with this method. In addition, this method is very simple and rapid, requiring only 20 min for the entire process, and is also safe because poisonous mercaptoethanol is replaced by dithiothreitol. The results of fiber-FISH with maize genomic DNA and 45S rDNA as probes showed that DNA fiber size as long as 1.96 Mb could be measured. The successful and reliable preparation of maize, wild rice, and barley DNA fibers suitable for FISH mapping proves that this technique is a widely effective approach for obtaining extended DNA fibers in plants. CONCLUSIONS: A simple, rapid, safe, and widely effective method for getting extended DNA fibers has been developed in plants. (c) 2005 Wiley-Liss, Inc.

Chromatin↗
PubMed2006

Retinal nerve fiber layer analysis in the diagnosis of glaucoma.

PURPOSE OF REVIEW: The detection of optic disc and retinal nerve fiber layer damage and change is the cornerstone of glaucoma management. Assessment of the retinal nerve fiber layer for localized and diffuse damage has been traditionally based on clinical examination, with documentation of change primarily qualitative. With the latest improvements in optical imaging instruments, objective and quantitative measurements of the retinal nerve fiber layer are now possible. This review summarizes the results from recent cross-sectional studies evaluating the discriminating ability of automated retinal nerve fiber layer measurements to detect glaucoma, and from longitudinal studies assessing the ability to predict and monitor glaucomatous changes. RECENT FINDINGS: Numerous cross-sectional studies have documented good diagnostic accuracy of a scanning laser polarimeter (GDx VCC), the optical coherence tomograph (Stratus), and the Heidelberg Retina Tomograph retinal nerve fiber layer measurements for differentiating between healthy and glaucoma eyes. There are only limited data available on the ability of these retinal nerve fiber layer measurements to document change over time. SUMMARY: It is essential that the clinician understand the specific strengths and weaknesses of each technique so that only good quality retinal nerve fiber layer information will be used in conjunction with careful clinical examination and visual function testing for glaucoma management decisions. Longitudinal studies are needed to evaluate the ability of these instruments to document retinal nerve fiber layer change over time.

Diagnostic Imaging↗
PubMed2002

[Effect of seedling stage shading on cotton yield and its quality formation].

The effect of shading during symbiotic stage of inter-cropped cotton and wheat on cotton yield and its quality formation was examined by simulated shading at the seedling stage of cotton. The results showed that the effect of shading on the cotton boll formation depended upon the position of fruiting branch and fruiting bud. For the bolls at low(1-3 fruiting branches) and middle(4-6 fruiting branches) parts and the inside bolls(1-2 fruiting buds) on upper(7-9 fruiting branches) fruiting branch, shading favored boll formation, but for the outside bolls (> or = 3 fruiting buds), especially at the top fruiting branch position, shading was unfavorable to boll formation. The effect of shading on the weight of individual boll also depended upon the position of fruiting branch and fruiting bud, but shading did not affect the mean boll weight per plant. For seed cotton yield per plant, the inside boll yield of shaded low and middle fruiting branches was higher than the control, but that of the upper and top fruiting branches was just contrary, the yield of outside bolls of all branches was lower than the control. For the distribution of the inside and outside bolls, shaded cotton was 1:0.36, versus 1:0.58 for the control. For the yield distribution, shaded cotton was 1:0.42, versus 1:0.72 for the control. The effect of shading on the cotton fiber and seed quality was mainly restricted on the bolls of top fruiting branches and the outside bolls of upper fruiting branches. The results also showed that different cotton varieties were different in their shade-tolerance, according to comprehensive analysis of the yield and quality formation, and the shade-tolerance of variety Zh9418 was stronger than that of Zh19 and CAZ.

Cotton Fiber↗
PubMed2003

Experimental investigation of cutoff phenomena in nonlinear photonic crystal fibers.

Modal cutoff is investigated experimentally in a series of high-quality nonlinear photonic crystal fibers. We demonstrate a suitable measurement technique with which to determine the cutoff wavelength and verify the technique by inspecting the near field of the modes that may be excited below and above the cutoff. We observe a double-peak structure in the cutoff spectra, which is attributed to splitting of the higher-order modes. The cutoff is measured for seven different fiber geometries with different pitches and relative hole sizes, and very good agreement with recent theoretical work is found.

Journal Article↗
PubMed2003

Fabrication optimisation of carbon fiber electrode with Taguchi method.

In this study, we describe an optimised procedure for fabricating carbon fiber electrodes using Taguchi quality engineering method (TQEM). The preliminary results show a S/N ratio improvement from 22 to 30 db (decibel). The optimised parameter was tested by using a glass micropipette (0.3 mm outer/2.5 mm inner length of carbon fiber) dipped into PBS solution under 2.9 V triangle-wave electrochemical processing for 15 s, followed by coating treatment of micropipette on 2.6 V DC for 45 s in 5% Nafion solution. It is thus shown that Taguchi process optimisation can improve cost, manufacture time and quality of carbon fiber electrodes.

Action Potentials↗
PubMed2004

Evaluation of visible and near-infrared spectroscopy as a tool for assessing fiber fineness during mechanical preparation of dew-retted flax.

Flax fiber must be mechanically prepared to improve fineness and homogeneity of the sliver before chemical processing and wet-spinning. The changes in fiber characteristics are monitored by an airflow method, which is labor intensive and requires 90 minutes to process one sample. This investigation was carried out to develop robust visible and near-infrared calibrations that can be used as a rapid tool for quality assessment of input fibers and changes in fineness at the doubling (blending), first, second, third, and fourth drawing frames, and at the roving stage. The partial least squares (PLS) and principal component regression (PCR) methods were employed to generate models from different segments of the spectra (400-1100, 1100-1700, 1100-2498, 1700-2498, and 400-2498 nm) and a calibration set consisting of 462 samples obtained from the six processing stages. The calibrations were successfully validated with an independent set of 97 samples, and standard errors of prediction of 2.32 and 2.62 dtex were achieved with the best PLS (400-2498 nm) and PCR (1100-2498 nm) models, respectively. An optimized PLS model of the visible-near-infrared (vis-NIR) spectra explained 97% of the variation (R(2) = 0.97) in the sample set with a standard error of calibration (SEC) of 2.45 dtex and a standard error of cross-validation (SECV) of 2.51 dtex R(2) = 0.96). The mean error of the reference airflow method was 1.56 dtex, which is more accurate than the NIR calibration. The improvement in fiber fineness of the validation set obtained from the six production lines was predicted with an error range of -6.47 to +7.19 dtex for input fibers, -1.44 to +5.77 dtex for blended fibers at the doubling, and -4.72 to +3.59 dtex at the drawing frame stages. This level of precision is adequate for wet-spinners to monitor fiber fineness of input fibers and during the preparation of fibers. The advantage of visNIR spectroscopy is the potential capability of the technique to assess fineness and other important quality characteristics of a fiber sample simultaneously in less than 30 minutes; the disadvantages are the expensive instrumentation and the expertise required for operating the instrument compared to the reference method. These factors need to be considered by the industry before installing an off-line NIR system for predicting quality parameters of input materials and changes in fiber characteristics during mechanical processing.

Flax↗
PubMed1999

Direct measurements of methane emissions from grazing and feedlot cattle.

Methane (CH4) emissions from animals represent a significant contribution to anthropogenically produced radiatively active trace gases. Global and national CH4 budgets currently use predictive models based on emission data from laboratory experiments to estimate the magnitude of the animal source. This paper presents a method for measuring CH4 from animals under undisturbed field conditions and examines the performance of common models used to simulate field conditions. A micrometeorological mass difference technique was developed to measure CH4 production by cattle in pasture and feedlot conditions. Measurements were made continuously under field conditions, semiautomatically for several days, and the technique was virtually nonintrusive. The method permits a relatively large number of cattle to be sampled. Limitations include light winds (less than approximately 2 m/s), rapid wind direction changes, and high-precision CH4 gas concentration measurement. Methane production showed a marked periodicity, with greater emissions during periods of rumination as opposed to grazing. When the cattle were grazed on pasture, they produced .23 kg CH4 x animal(-1) x d(-1), which corresponded to the conversion of 7.7 to 8.4% of gross energy into CH4. When the same cattle were fed a highly digestible, high-grain diet, they produced .07 kg CH4 x animal(-1) x d(-1), corresponding to a conversion of only 1.9 to 2.2% of the feed energy to CH4. These measurements clearly document higher CH4 production (about four times) for cattle receiving low-quality, high-fiber diets than for cattle fed high-grain diets. The mass difference method provides a useful tool for "undisturbed" measurements on the influence of feedstuffs and nutritional management practices on CH4 production from animals and for developing improved management practice for enhanced environmental quality.

Animal Feed↗
PubMed1993

Developing a fiber-optic probe to combine subcutaneous fat depth and meat quality measurements.

This feasibility study demonstrates that the boundary between porcine subcutaneous fat and longissimus muscle can be detected with a probe using optical fibers to illuminate and detect anatomical boundaries. A relatively large optical window (approximately 3 mm2) seemed to give the best resolution of fat to muscle boundaries, whereas a smaller window gave a better resolution of marbling. Scattered, obliquely sectioned optical fibers gave reflectance spectra of fat and muscle that were relatively flat and parallel (fat > muscle). Thus, white light may be used with optical fibers to detect fat to muscle boundaries, although the greatest monochromatic separation was at 820 nm. In comparing measurements made as the probe penetrated the meat with those made as the probe was withdrawn, structures appeared to be deeper on the way in than on the way out, because of compression of the meat. Multichannel operation allowed tissue transmittance to be measured as well as reflectance and channels to be averaged to improve performance. These observations will be useful in developing new apparatus to measure fat depth and meat quality in one operation using optical fibers.

Adipose Tissue↗
PubMed2001

Enzyme-retting of flax and characterization of processed fibers.

Enzyme-retting formulations consisting of Viscozyme L, a pectinase-rich commercial enzyme product, and ethylenediaminetetraacetic acid (EDTA) were tested on Ariane fiber flax and North Dakota seed flax straw residue. Flax stems that were crimped to disrupt the outer layers were soaked with various proportions of Viscozyme-EDTA solutions, retted, and then cleaned and cottonized with commercial processing equipment. Fiber properties were determined and crude test yarns were made of raw and Shirley cleaned flax fibers and cotton in various blend levels. Cleaned fibers were obtained from both seed and fiber flax types, but with variations due to treatment. Retting formulations produced fibers having different properties, with enzyme levels of 0.3% (v/v as supplied) giving finer but weaker fibers than 0.05% regardless of EDTA level. Experimental yarns of blended flax and cotton fibers varied in mass coefficient of variation, single end strength, and nep imperfections due to sample and formulation. With cost and fiber and yarn quality as criteria, results established a range in the amounts of components comprising retting formulations as a basis for further studies to optimize enzyme-retting formulations for flax. Under conditions examined herein, Viscozyme L at 0.3% (v/v) plus 25 mM EDTA produced the best test yarns and, therefore, established a base for future studies to develop commercial-grade, short staple flax fibers for use in textiles.

Edetic Acid↗
PubMed2002

The adaptive potential of skeletal muscle fibers.

Mammalian skeletal muscle fibers display a great adaptive potential. This potential results from the ability of muscle fibers to adjust their molecular, functional, and metabolic properties in response to altered functional demands, such as changes in neuromuscular activity or mechanical loading. Adaptive changes in the expression of myofibrillar and other protein isoforms result in fiber type transitions. These transitions occur in a sequential order and encompass a spectrum of pure and hybrid fibers. Depending on the quality, intensity, and duration of the alterations in functional demand, muscle fibers may undergo functional transitions in the direction of slow or fast, as well as metabolic transitions in the direction of aerobic-oxidative or glycolytic. The maximum range of possible transitions in either direction depends on the fiber phenotype and is determined by its initial location in the fiber spectrum.

Adaptation, Physiological↗