julilili42/papers huggingface dataset:
M�ller glial cells in anuran retina
2000-01-01

Whereas in the brain, the activity of the neurons is supported by several types of glial cells such as astrocytes, oligodendrocytes, and ependymal cells, the retina (evolving from the brain during ontogenesis) contains only one type of macroglial cell, the Müller (radial glial) cells, in most vertebrates including the anurans. These cells span the entire thickness of the tissue, and thereby contact and ensheath virtually every type of neuronal cell body and process. This intimate topographical relationship is reflected by a multitude of functional interactions between retinal neurons and Müller glial cells. Müller cells are the principal stores of retinal glycogen, and are thought to fuel retinal neurons with substrate (lactate/pyruvate) for their oxidative metabolism. Furthermore, Müller cells are involved in the control and homeostasis of many constituents of the extracellular space, such as potassium and perhaps other ions, signaling molecules, and of the extracellular pH. They also seem to play important roles in recycling mechanisms of photopigment molecules and neurotransmitter molecules such as glutamate and GABA. By containing the main retinal stores of glutathione, Müller cells may protect retinal neurons against free radicals. Moreover, Müller cells express receptors for many neuroactive substances, and may also release such substances to their neighbouring neurons. Thus, Müller cells exert many functions crucial for signal processing in the normal retina. Moreover, Müller cells change their properties in cases of retinal disease and injury, and may either support the survival of neuronal cells or accelerate the progress of neuronal degeneration.
Determination of the enantiomerization barrier of oxazepam by dynamic micellar electrokinetic chromatography--comparison of experiment and simulation with ChromWin 99.
2000-01-01

The pH-dependent and temperature-controlled enantiomerization of oxazepam has been studied by dynamic micellar electrokinetic chromatography in an aqueous buffer system with sodium cholate as the chiral surfactant. Experimental interconversion profiles featuring plateau formation were simulated by the new program ChromWin 99. Peak form analysis yielded rate constants and kinetic activation parameters of the enantiomerization of oxazepam between 5 degrees C and 25 degrees C.
Factors Influencing Capping and Cracking of Mefenamic Acid Tablets
2000-01-01

The tendency of capping and longitudinal cracks of mefenamic acid tablets was evaluated in relation to the amount of the binder, the influence of the granulation technique, and the relative humidity of the granules. Tablets made from fluidized bed granules using methylcellulose in the granulating liquid showed significantly lower capping and longitudinal cracks than tablets from conventional granules prepared by wet granulation using methylcellulose as a dry binder.
Oxidative stress increases potassium efflux from pancreatic islets by depletion of intracellular calcium stores
2000-01-01

Oxidative stress to B-cells is thought to be of relevance in declining B-cell function and in the process of B-cell destruction. In other tissues including heart, brain and liver, oxidative stress has been shown to elevate the intracellular free calcium concentration and to provoke potassium efflux. We studied the effect of oxidative stress on Ca2+ and K+ (Rb+) outflow from pancreatic islets using the thiol oxidants DIP and BuOOH. Both compounds reversibly increased 86Rb+ efflux in the presence of 3 and 16.7 mmol/l glucose. Stimulation of 86Rb+ efflux was also evident in the absence of calcium. DIP evoked release of 45Ca2+ from the pancreatic islets both in the presence or absence of extracellular calcium. Employing inhibitors of the calcium-activated potassium channel (KCa) and the high conductance K+-channel (BKCa), the effect of DIP on 86Rb+ efflux was slightly diminished. Tolbutamide had no effect on 86Rb+ efflux in the presence of DIP. On the other hand thapsigargin, a blocker of the Ca+-ATPase of the endoplasmic reticulum, completely suppressed the DIP-mediated 86Rb+ outflow. The data suggest that thiol oxidant-induced potassium efflux from pancreatic islets is mainly mediated through liberation of intracellular calcium and subsequent stimulation of calcium-activated potassium efflux.
Acquired generalized lipoatrophy (AGL): Highly selective MR lipid imaging and localized1H-MRS
2000-01-01

Frequency-selective chemical shift magnetic resonance (MR) imaging was applied on the calf musculature and the abdomen of a patient with acquired generalized lipoatrophy (AGL; Lawrence syndrome), a very rare syndrome affecting selectively several types of adipose tissue accompanied by alterations in glucose and energy metabolism. In addition, (1)H-MRS was used for assessment of intra- (IMCL) and extramyocellular lipid stores (EMCL) in the skeletal musculature of the calf. Results from the AGL patient were compared with an age-matched group of five healthy volunteers. Fat-selective imaging of the calf revealed a total lack of subcutaneous adipose tissue. No EMCL signal was found in the spectra from the soleus muscle of the AGL patient. IMCL signals were present in the spectra but were clearly lower than in the controls (14% of normal value in the soleus muscle). In abdominal images, subcutaneous fat signal was not detectable, as in the calf, but nearly normal conditions were shown for visceral adipose tissue between abdominal organs. Fat-selective images showed the liver with high signal intensity, indicating hepatic steatosis combined with hepatosplenomegaly. Modern chemical shift-selective MR imaging and localized spectroscopy allow a noninvasive and quantitative assessment of tissue composition in patients with disorders of carbohydrate and lipid metabolism.
Solar UV-Protective Properties of Textiles
2000-01-01

Skin cancer is increasing worldwide, and exposure to ultraviolet (UV) radiation is thought to be the most important risk factor [1, 2]. Outdoor professionals and people practising outdoor sports are considerably exposed to solar UV radiation [3]. We have reported high personal UV exposure in cycling professionals up to about 17 MED/day [4]. Obviously, adequate protection is mandatory. Here, a sports dress can offer high-quality protection against UV radiation. In Europe a standard of solar UV-protective properties of textiles is being discussed (European Committee for Standardisation CEN/TC248 WG14).We evaluated the UV protection of 4 different cycling jerseys in a total of 7 colours ['maillot jaune', 'maillot vert', 'maillot à pois' of the Tour de France 1998 (Nike) and the cycling jersey of the Team Deutsche Telekom 1998 (Adidas)]. (1) The jerseys were horizontally exposed to sunlight. (2) The jerseys were worn as a cycling dress. In these experiments, UV doses were measured with cosinus-correcting spore film dosimeters (Viospor, Biosense, Bornheim, Germany). The sun protection factor measured is the fraction of erythemally weighted incident radiation on the textile and transmitted radiation under the textile. (3) In addition, we tested UV transmission with a spectrophotometer according to the Australian and (proposed) European standard [5].The results are summarized in table 1.The textiles had comparable sun protection factors when tested with the standard procedure or under stationary sun exposure with spore film dosimeters.Yet, the cycling jerseys revealed a much higher sun protection when tested under 'real' conditions. This could be explained by the fact that the laboratory standard test procedure used UV light orthogonally incident to the fabric. But the structure of the fabric will offer higher protection to oblique or diffuse solar UV exposure.In conclusion, the proposed European standard may underestimate sun protection by textiles. Professional cyclists exposed to an extreme UV radiation are absolutely not tanned on sites covered by the cycling dress. Even jerseys with low sun protection factors (e.g. Team Deutsche Telekom jersey) clinically offer perfect protection.Nevertheless, it is best in the 'maillot jaune'!We would like to thank Dr. Quintern and Dr. Holtschmidt for their support in spore film dosimetry and Dr. Hoffmann for his help with the spectrophotometer of the Department of Dermatology, Ruhr University, Bochum, Germany.
Synthesis of Ladder-Type Oligomers Incorporating Phthalocyanine Units
2000-01-01

The condensation of substituted diiminoisoindolines with alkyl-substituted 1,3,3-trichloroisoindolines results in the formation of the highly soluble metal-free phthalocyanines 9, 15. By the same methodology, metal-containing phthalocyanines such as 16, 18 are accessible from suitable metal salts. The precursors 24 and26 were obtained from the phthalocyanine 9 and tetracyclone. The generation of the phthalocyanines 23 and 25 possessing isobenzofuran moieties as diene subunits was accomplished; in the presence of excess 28, the tetracyclone-bisadducts 22 and 24 were transformed into the model compounds 29 and 30, while an excess of 20 or 9 leads to the appropriate trimer-oligomers 31 and 32.
The color constancy of the red-green color blind
2000-01-01

The color constancy of 5 normal and 10 red-green color deficient (4 protanopes, 3 deuteranopes, 3 deuteranomalous trichromats) observers was investigated by an achromatic matching task, in which they were required to adjust the color of a central patch within a scene until it appeared as a neutral gray. The patch was presented in the middle of a CRT Mondrian display, which was initially set to CIE Illuminant C or D65 and then shifted along either the red-green cardinal axis, blue-yellow cardinal axis, or Planckian locus. Despite their significantly higher red-green discrimination thresholds, color deficient observers display color constancy similar to that of normal observers along all three axes. However, their variability is greater for settings along the red-green cardinal axis. © 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S209–S213, 2001
Endothelin-Receptor Antagonists in Uremic Cardiomyopathy
2000-01-01

Increased endothelin-1 (ET-1) levels were found in patients with chronic renal failure. These correlate with the severity of renal failure. Patients with elevated ET-1 concentrations show an increased cardiovascular mortality. The prevalence of severe left ventricular hypertrophy (LVH) is a very important factor for survival and morbidity in uremic patients The aim of this study was to assess the protective effect of ET-receptor antagonists in chronic uremia. Sprague Dawley rats were subtotally nephrectomized (SNX) and treated either with the endothelin-A- (ET(A)) receptor antagonist LU302146 or with the unselective ET(A)/ET(B)-receptor antagonist LU302872 (30 mg/kgbw/day both). After subtotal nephrectomy protein excretion SNX (130.0 +/- 22.5 mg/24 h) was increased in comparison to the ET(A)-group (446 +/- 103 mg/24 h) and the ET(AB)-group (23.2 +/- 37 mg/24 h) vs sham: 115 +/- 19 mg/24 h). Heart weight was decreased by the ET(A)/ET(B)-receptor antagonist LU302146. Left ventricular contractility was impaired in SNX by about 40%. Treatment with the ET-receptor antagonists prevented the impairment in left ventricular function. Our study results provide a possible therapeutic approach using ET receptor antagonists to reduce cardiac hypertrophy and renal proteinuria. Further human studies are needed to show whether this protection of the heart and kidney might influence the survival and life-expectancy of patients suffering from chronic renal failure.
Learning and Self-Regulation of Slow Cortical Potentials in Older Adults
2000-01-01

Two groups of subjects, aged 20-28 and 50-64, respectively, matched for health status and verbal abilities, learned to control their slow cortical potentials (SCP) in a feedback paradigm by producing, on command, SCP shifts in either positive or negative direction. Both groups were able to differentiate significantly between the positivity task and the negativity task, with the differentiation score being only slightly (and not significantly) lower in older than in younger subjects. In all conditions, however, significantly more negative brain responses were obtained in older than in younger subjects. This effect was larger in the positivity task versus negativity task, and larger in trials without continuous SCP feedback versus trials with feedback. Additionally four learning tasks were carried out with all subjects. The older group demonstrated substantial performance deficits in two tasks with explicit learning (verbal and visual). In contrast, implicit learning (perceptual learning and skill acquisition) was not impaired with age. The results are at odds with the idea of general age-related learning deficit and concur with the hypothesis that only explicit, but not implicit, learning processes are compromised in older subjects. The pattern of consistently more negative SCP shifts produced by elderly subjects may indicate their impaired cortical inhibition. Another interpretation, which does not exclude the inhibitory deficit hypothesis but seems to better agree with other psychophysiological data, may be that older subjects have disturbance in the system controlling arousal and effort.
Regulatory cell interactions between retinal ganglion cells and radial glia during axonal and dendritic outgrowth
2000-01-01

Neuronal differentiation and the formation of cell polarity are crucial events during the development of the nervous system. Cell polarity is a prerequisite for directed information flux within neuronal networks. In this article, we focus on neuro-glial cell interactions that influence the establishment of neural cell polarity and the directed outgrowth of axons versus dendrites. The cellular model discussed in detail is the retinal ganglion cell (RGC) of the chick retina, which is investigated by a comprehensive set of in vitro assays. The experiments demonstrate that retinal microenvironment determines axon vs. dendrite formation of RGCs. The instructive differences in different retinal microenvironments are substantially influenced by radial glia. Different glial domains support or inhibit axon vs. dendrite outgrowth. The data support the notion that neuro-glial interactions are crucial for directed neurite outgrowth.
Urodynamic and rectomanometric findings in patients with spinal cord injury
2000-01-01

Patients with spinal cord lesion suffer from complex disorders of bladder and anorectal function. We assessed the value of urodynamics and anorectal manometry as prognostic and diagnostic tools in these patients and evaluated the usefulness of these techniques for the differentiation between complete and incomplete spinal cord lesions. Thirty patients with suprasacral spinal cord injury (six women, 24 men; mean age, 31 years) underwent anorectal manometry and urodynamics within the first 40 days after injury. The findings were compared to the results of a clinical neurologic evaluation. Fifteen patients were classified as complete lesions on their clinical signs, three of these lesions were incomplete according to urodynamic testing and five were incomplete according to visceral sensory testing by anorectal manometry. Despite significant differences in maximum bladder capacity (589 versus 465 mL), maximum detrusor pressure (18 versus 31 cm H2O) was not significantly different between patients with complete and patients with incomplete spinal cord injury. Anorectal manometry did not reveal any significant differences in resting pressure, abdominal pressure, and maximal rectum volume between these groups. Urodynamics and anorectal manometry may be superior to neurologic assessment of completeness of spinal cord lesions. Urodynamics and anorectal manometry were not helpful in the prediction of onset or severity of detrusor hyperreflexia. Thus, we do not regard anorectal manometry as a standard diagnostic tool in spinal cord injury patients.
Motor reorganization after spinal cord injury: evidence of adaptive changes in remote muscles
2000-01-01

Purpose: Given that SCI leads to substantial changes in biomechanical properties of the body and to widespread postlesional reorganization of the motor system as determined by functional imaging studies, we sought to identify neurophysiological correlations and time course of reorganization affecting muscles more distant to a SCI. Methods: Two arm muscles distant to a SCI (T2-L3), M.biceps brachii (BIC), M.abductor pollicis brevis (APB), were studied in 13 SCI-patients and 15 controls. Motor thresholds at rest (MT), facilitatory effects on MEP-amplitudes (FE) with voluntary activation, MEP-amplitudes with maximal stimulation (MA) and recruitment curves (RC) were measured and correlated with level, age and severity of the lesion. Follow-up studies (t2) were performed in five patients with clinical recovery. Results: Patients exhibited smaller MA from activated BIC, a tendency towards smaller FE and smaller RC-slopes at t1. With clinical recovery, activated BIC-FE, MA and RC-slopes tended to normalize. Conclusions: Our data support the hypothesis that postlesional reorganization of the motor system also involves remote muscles. Considering pattern and time course of reorganization, we speculate that they appear as sequelae of the trauma, possibly representing an adaptation of the motor system to an altered biomechanical status after SCI.
Precambrian “fossil” Vermiforma is a tectograph
2000-01-01

Research Article| March 01, 2000 Precambrian "fossil" Vermiforma is a tectograph Adolf Seilacher; Adolf Seilacher 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06511, USA Search for other works by this author on: GSW Google Scholar Martin Meschede; Martin Meschede 2Institut für Geologie und Paläontologie, Universität Tübingen, 72076 Tübingen, Germany Search for other works by this author on: GSW Google Scholar Edward W. Bolton; Edward W. Bolton 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06511, USA Search for other works by this author on: GSW Google Scholar Hans Luginsland Hans Luginsland 2Institut für Geologie und Paläontologie, Universität Tübingen, 72076 Tübingen, Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Adolf Seilacher 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06511, USA Martin Meschede 2Institut für Geologie und Paläontologie, Universität Tübingen, 72076 Tübingen, Germany Edward W. Bolton 1Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06511, USA Hans Luginsland 2Institut für Geologie und Paläontologie, Universität Tübingen, 72076 Tübingen, Germany Publisher: Geological Society of America Received: 12 Jul 1999 Revision Received: 10 Dec 1999 Accepted: 20 Dec 1999 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2000) 28 (3): 235–238. https://doi.org/10.1130/0091-7613(2000)28<235:PFVIAT>2.0.CO;2 Article history Received: 12 Jul 1999 Revision Received: 10 Dec 1999 Accepted: 20 Dec 1999 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Search Site Citation Adolf Seilacher, Martin Meschede, Edward W. Bolton, Hans Luginsland; Precambrian "fossil" Vermiforma is a tectograph. Geology 2000;; 28 (3): 235–238. doi: https://doi.org/10.1130/0091-7613(2000)28<235:PFVIAT>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Vermiforma antiquaCloud 1976, once celebrated as the earliest animal fossil of the United States, is actually a tectonic artifact. The main argument is that the congruence and equal orientation of multiple patterns on the same bedding plane are incompatible with swaying worm bodies or worm burrows. As shown by analog and numerical simulations, these structures can be explained as tracks of particles that broke out from the base of an overlying turbidite and became rolled between beds during bed-to-bed shearing. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Learning syntactic structures with XML
2000-01-01

We present the result of a symbolic machine learning system for the CoNLL-2000 shared task. This system, ALLiS, is based on theory refinement. In this paper we want to show that XML format not only offers a good framework to annotate texts, but also provides a good formalism and tools in order to learn (syntactic) structures.
Catalytic Oxidation of a Trialkyl-Substituted Phenol and Aniline with Biomimetic Schiff Base Complexes
2000-01-01

The catalytic oxidation of 2,4.6-tri-tert-butylphenol and 2,4,6-tri-tert-butylaniline with molecular oxygen and tert-butylhydroperoxide was investigated using biomimetic Mn-, Fe- and Co-complexes as catalysts. The catalytic activity and product distribution were determined and compared with those observed in the reactions of the well-known Co(salen) complex
Systems technology in the operating theatre: A prerequisite for the use of advanced devices in surgery
2000-01-01

The development of endoscopic techniques has significantly changed surgery. The increasing complexity of devices being used has increased the demand for improved ergonomics and functionality. Since the early 1990s the development of system solutions for the operating room (OR) has been a topic of major interest for surgeons and industry. The first integrated surgical workplace system was introduced by Dornier (Orest) in 1994. Several other solutions are now commercially available. Their common feature is the ability to control the different functions of the individual devices (e.g. high-frequency waves, camera, or insufflation) via remote control systems directly from the operating table. Other developments in OR systems include ergonomic aids for the surgeon, such as a chair dedicated to the functional needs of endoscopic surgery. The chair is powered by electric motors controlled by a foot-pedal joystick and its position can be altered to achieve the desired position in the OR. Also significant in endoscopic surgery was the introduction of robotic technology, namely devices that assist solo-surgery and manipulators for microsurgical instrumentation.
Evaluation and Validation of a Fully Instrumented Hüttlin HKC 05-TJ Laboratory-Scale Fluidized Bed Granulator
2000-01-01

The instrumentation and validation of a laboratory-scale fluidized bed apparatus is described. For continuous control of the process, the apparatus is instrumented with sensors for temperature, relative humidity (RH), and air velocity. Conditions of inlet air, fluidizing air, product, and exhaust air were determined. The temperature sensors were calibrated at temperatures of 0.0 degree C and 99.9 degrees C. The calibration of the humidity sensors covered the range from 12% RH to 98% RH using saturated electrolyte solutions. The calibration of the anemometer took place in a wind tunnel at defined air velocities. The calibrations led to satisfying results concerning sensitivity and precision. To evaluate the reproducibility of the process, 15 granules were prepared under identical conditions. The influence of the type of pump used for delivering the granulating liquid was investigated. Particle size distribution, bulk density, and tapped density were determined. Granules were tableted on a rotary press at four different compression force levels, followed by determination of tablet properties such as weight, crushing strength, and disintegration time. The apparatus was found to produce granules with good reproducibility concerning the granule and tablet properties.