cssi/SciSciGPT-SciSciNet huggingface dataset:
Poststress redistribution of thallium-201 in patients with coronary artery disease, with and without prior myocardial infarction

Abstract To elucidate patterns of thallium-201 redistribution with and without myocardial infarction, to determine the value of thallium-201 redistribution scintigrams in identifying additional ischemic myocardium in the presence of prior myocardial infarction and to delineate the relation of collateral vessels to redistribution, thallium-201 myocardial perfusion scintigraphy was performed immediately after exercise and 4 to 6 hours after exercise in 46 patients with coronary artery disease and 12 normal control subjects. Scintigrams were interpreted in the conventional visual manner as well as with use of computer-processed myocardial perfusion ratios. Normal control subjects demonstrated uniform thallium-201 distribution with regional perfusion ratios approximating unity in both the early and delayed scintigrams. Of 27 patients with prior myocardial infarction, 5 (19 percent) had complete redistribution on delayed imaging, 17 (62 percent) had partial redistribution and 5 (19 percent) had no redistribution. Of 25 regions corresponding to electrocardiographlc evidence of infarction, 8 (32 percent) had total, 8 (32 percent) had partial and 9 (36 percent) had no redistribution. Collateral vessels were absent or of poor quality in seven of eight infarct areas with no redistribution; three of four infarct regions with normal early thallium uptake were supplied by collateral vessels of good quality. Of 12 regions supplied with good collateral vessels, 9 had complete redistribution, 2 partial and 1 no redistribution. In contrast, only 2 of 21 hypoperfused zones without redistribution (10 percent) were supplied by good collateral vessels. Of 19 patients without prior myocardial infarction, 10 (53 percent) had complete redistribution, 6 (31 percent) had partial redistribution and 3 (16 percent) had no redistribution. Of the 34 abnormal areas in the immediate postexercise image, 22 (65 percent) showed total redistribution, 3 (9 percent) showed partial redistribution and 9 (26 percent) showed no redistribution. Thus, considerable overlap in redistribution scintigrams occurs in patients with coronary artery disesase with and without prior infarction; a high incidence rate of transient stress-induced hypoperfusion occurs in both infarcted and noninfarcted myocardium. Further, good quality collateral vessels afford redistribution, even to some areas of prior infarction. These data indicate that because delayed postexercise redistribution imaging may not discriminate between myocardial scar and ischemia resting scintigrams may be needed in a substantial number of patients.
Assessment of super-resolution for face recognition from very-low resolution images in sensor networks

ABSTRACT Super-Resolution (SR) involves the registration of multiple images/frames and reconstruction of a single higher resolution image. The goal of this research is to use multip le, very-low resolution images, such as those produced from a video sequence in a wireless sensor network system, as input to the super-resolution process in a face recognition system. The algorithm used for face reco gnition is the Fisherfaces method with a n earest neighbor classifier used for the recognition decision. Super-resolution consists of two stages, a registration stage and a reconstruction stage. Testing images were segmented using a simple skin color detection approach. After cropping they were combined into groups of four to be used for the super-resolution algorithm using faces from three people. Each group of four images was used as an input to the Keren registration algorithm where the rotational and translation information was saved that was then entered into the robust super-resolution reconstruction algorithm to create a single high quality image, which was processed by the face recognition algorithm. An av erage of the same groups of four was tested as well as a centroid shifted average. Comparison was based on n earest neighbor classifier and on classification rates. The results were not in favor of the super-resolution method but instead, the centroid shifted average was the best in this study. Keywords: Face Recognition, Super-Resolution, Fish erfaces, Nearest Neighbor Classifier
New method for development of carbon clad silica phases for liquid chromatography: Part I. Preparation of carbon phases.

Abstract Owing to its combination of unique selectivity and mechanical strength, commercial carbon clad zirconia (C/ZrO 2 ) has been widely used for many applications, including fast two-dimensional liquid chromatography (2DLC). However, the low surface area available (only 20–30 m 2 /g for commercial porous ZrO 2 ) limits its retentivity. We have recently addressed this limitation by developing a carbon phase coated on the high surface area of HPLC grade alumina (C/Al 2 O 3 ). This material provides higher retentivity and comparable selectivity, but its use is still limited by how few HPLC quality types of alumina particles (e.g., particle size, surface area, and pore size) are available. In this work, we have developed useful carbon phases on silica particles, which are available in various particle sizes, pore sizes and forms of HPLC grade. To make the carbon phase on silica, we first treat the silica surface with a monolayer or less of metal cations that bind to deprotonated silanols to provide catalytic sites for carbon deposition. After Al (III) treatment, a carbon phase is formed on the silica surface by chemical vapor deposition at 700 °C using hexane as the carbon source. The amount of Al (III) on the surface was varied to assess its effect on carbon deposition, and the carbon loading was varied at different Al (III) levels to assess its effect on the chromatographic properties of the various carbon adsorbents. We observed that use of a concentration of Al (III) corresponding to a full monolayer leads to the most uniform carbon coating. A carbon coating sufficient to cover all the Al (III) sites, required about 4–5 monolayers in this work, provided the best chromatographic performance. The resulting carbon phases behave as reversed phases with reasonable efficiency (50,000–79,000 plates/m) for non-aromatic test species.
Twelve-electron organochromium species: synthesis and characterization of high-spin square-planar chromium(II) alkyls and aryls

Alkylation of the chromium phosphine complex [CrCl 2 (dippe)] 2 (dippe=1,2-bis(diisopropylphosphino)ethane) with Grignard or dialkylmagnesium reagents gives the unusual 12-electron chromium(II) alkyls cis-CrR 2 (dippe) (R=CH 2 CMe 3 , CH 2 SiMe 3 , C 6 H 2 Me 3 ). The unidentate phosphine complex trans-Cr(C 6 H 2 Me 3 ) 2 (PMe 3 ) 2 may be prepared similarly by treatment of CrCl 2 (THF) with dimesitylmagnesium in the presence of PMe 3 . All of these four-coordinate alkyls possess magnetic moments characteristic of high-spin species, and exhibit broadened 1 H NMR resonances consistent with the paramagnetism. X-ray crystal structures of Cr(CH 2 CMe 3 ) 2 (dippe) and Cr(CH 2 SiMe 3 ) 2 (dippe) reveal tetrahedrally distorted square-planar structures
Exchange rate systems and linkages in the pacific basin

This paper analyzes the exchange rate systems of 10 Pacific Basin economies and linkages of their currencies with the major currencies. The recent advances in time series analysis, including unit root tests and cointegration tests, are utilized for this purpose. The results suggest that while many Pacific Basin developing economies are inclined to have a peg or crawling peg system and peg their currencies primarily to the U.S. dollar, the influence of the Japanese yen in this region is also strong, especially on the exchange rates of the Asian newly industrializing economies. For Australia and New Zealand, their exchange rates move in tandem.
Responses of nonstructural carbohydrates to shoot removal and soil moisture treatments in Salix nigra

Aboveground disturbances are common in dynamic riparian environments, and Salix nigra is well adapted with a vigorous resprouting response. Soil moisture stresses are also common, and S. nigra is flood tolerant and drought sensitive. The objective of this study was to quantify nonstructural carbohydrate (NSC) reserves in S. nigra following shoot removal and soil moisture treatments. NSC reserves provide energy for regeneration of shoot tissue until new functional leaves are developed. Three soil moisture treatments: well-watered (W), periodic flooding (F) and drought (D); and three shoot removal treatments: no shoots removed (R0), partial shoot removal (R1), and complete shoot removal (R2) were applied. Plants were harvested when new shoot development was observed (day 13). Statistical significance in the 3 × 3-factorial design was determined in two-factor ANOVA at P < 0.05. Both roots and cuttings were important reservoirs for NSC during resprouting response, with decreases in root (31%) and cutting (14%) biomass in R2 compared to R0. Rapid recovery of photosynthetic surface area (from 15 to 37% of R0) was found in R1. A clear pattern of starch mobilization was found in roots in R0, R1 and R2, with lowest root starch concentration in W, F higher than W, and D higher than F. Shoot starch concentration was lower in F and D compared to W in R0, however, in R1 shoot starch was reduced in W compared to F and D, possibly indicating reduced rates of translocation during soil moisture stress. Evidence of osmotic adjustment was found in roots and shoots with higher total ethanol-soluble carbohydrates (TESC) during soil moisture stress in F and D treatments. Total plant NSC pool was greater in F and D treatments compared to W, and progressively reduced from R0 to R1 to R2. Results indicated negative effects of drought, and to a lesser extent periodic flooding on resprouting response in S. nigra, with implications for reduced survival when exposed to combined stresses of aboveground disturbance and soil moisture.
Benchmarking performance measures in traditional and just‐in‐time companies

Purpose – The purpose of this paper is to show if there are differences between traditional and just‐in‐time ( JIT) companies in choosing benchmarking performance measures at various levels of organization.Design/methodology/approach – A questionnaire‐based mailed survey was used to examine five questions on the differences between traditional and JIT companies. The target population for the study was manufacturing firms in midwestern USA. The sample covers organizations in a variety of industries ranging from fabricated metal, communication, electronics, automotive, toots, chemicals, rubber, and paper products. In addition to general organization and managerial profile items, the survey contained series of questions regarding organizational goals and objectives, competitive priorities, manufacturing performance objectives, and manufacturing action plans. Out of 91 completed surveys received, 84 surveys were usable resulting in a response rate of 17 percent. Out of 84 usable surveys, 33 respondents declar...
Multi-Spectral Scale And Rotation Invariant Associative Memory Method For Pattern Recognition

The method of using log-polar mapping with spectral band separation to form feature vectors for an associative memory is investigated. Log-polar mapping is used to provide the scale and rotation invariant properties. This reduces the teaching time and total capacity requirement for the associative memory because all orientations and sizes of the target object need not be learned. The images are also broken down into spatial frequency bands. The use of this technique is motivated by evidence that similar processes occur in the human visual system. Suspected benefits include enhanced recognition in the presence of noise and improved network robustness. Simulation results are presented for the case of character recognition.
Polar-optical-mode scattering for an ideal quantum-well heterostructure

It is pointed out that approximations, such as have been proposed, in the normal-direction form factor which enters into the basic lattice scattering rates for two-dimensional heterolayer transport are not necessitated by the singularities of this form factor in the ideal "quantum-well" case. The $H(Q)$ function which actually governs the polar-optical-mode scattering rates in this case is not singular. It is given as an analytical function of the two-dimensional transfer wave vector and is displayed in a numerical plot.
The Split Nucleus of Comet Wilson (C/1986 P1 = 1987 VII)

Abstract We present CCD observations of Comet Wilson (C/1986 P1 = 1987 VII) from 26 nights during the time period 1986 October to 1991 February, which brackets perihelion, During the observing run of 1988 February, the comet was observed to have split into two fragments. Our broadband CCD photometry, along with photometry from the International Cometary Quarterly , shows a steady decline in brightness of Comet Wilson post-perihelion, with an outburst between heliocentric distances r = 2.8 and 3.3 AU during 1987 October and November. By r ≈ 7 AU, the fragment had faded with respect to the parent and was no longer centrally condensed. A brightness limit of m R ≈ 25, when the comet was at r = 12.65 AU, constrains the primary nucleus to have a maximum radius between 5 and 7 km, assuming an albedo of 0.04. The accuracy of direct orbital solutions for the parent body and fragment to determine the time of splitting was limited by the presence of significant nongravitational forces and the limited fragment orbital coverage. We used the relative position of the fragment with respect to the parent to calculate a time of splitting which was consistent with the time of the observed outburst. We discuss the possible causes of the splitting. The coma of Comet Wilson was observed to have a surface-brightness profile which fell off as p -1 (characteristic of a canonical steady-state coma under the influence of radiation pressure) for all of the data with the exception of the data taken during 1987 November when the gradient was p -1.3 . This steeper slope was probably caused by the injection of new material into the coma during the outburst. During 1986 October, there was a break in the surface-brightness profile slope which may be interpreted as the distance at which grains are swept into the tail. The profiles suggested grain velocities of a few x 10 2 to 10 m sec -1 for grains between 1 and a few hundred micrometers. Finson-Probstein dust modeling showed that ejection of grains began preperihelion at r gt; 6 AU, peaking near perihelion with a very rapid decline thereafter, with an outburst occurring roughly 170 days post-perihelion. We found no evidence for the existence of discrete features in the coma. Both the primary and fragment nuclei grew redder with time, with the fragment being redder than the parent, consistent with the picture of smaller grains leaving the field of view of the aperture more quickly than larger grains.
Subquarter-micrometre elevated source-and-drain MOSFET structure using polysilicon spacers

A novel subquarter-micrometre MOSFET with a selfaligned source and drain structure is proposed with elevated sources and drains formed by using polysilicon spacers. The spacers can reduce the effective channel length by 50% compared to the mask length, and reduce the junction capacitance by over 30% through a reduction in junction area, as shown by PISCES simulations. A graded oxide spacer is used to decrease the parasitic gate-to-drain capacitance.
Investigation of ethylene-vinyl alcohol copolymers for surface modification of contact lenses

Ethylene-vinyl alcohol copolymers from 0 to 57 mol % of vinyl alcohol were investigated for potential contact lens surface modification. Films of the ethylene-vinyl alcohol copolymers made by solution casting, showed that the copolymers with a high percentage of vinyl alcohol groups possessed excellent surface properties such as good wettability, low protein (albumin) and lipid adsorption, and no conformational change of the adsorbed protein
Challenges and solutions for trench lithography beyond 65nm node

Due to complex interconnect wiring scheme and constraints from process rules, systematic defects such as pattern necking and bridging are a major concern for metal layers. These systematic defects or "weak spots" can be major yield detractors in IC manufacturing if not properly addressed. These defects can occur even in cases where model-based OPC has been implemented, as well as a variety of process rules for margin insurance. Determining how to improve the marginalities or "weak spots" becomes a key factor for enhancing product yields. This paper will address several root causes for pattern induced defects and present solutions to a variety of weak spots including "T-shape," "H-shape," "Thin-Line," and "Bowling Pin" defects during 65nm product development at TI. Through case studies, we demonstrate how to successfully provide DFM (Design for Manufacturing) by using Resolution Enhancement Techniques (RET) tools to avoid and minimize the weak spots. Furthermore, process techniques to improve printability for some of the weak spots as applied to 65nm reticle sets will be discussed. An integrated scheme aiming at optimization of design rules and process rules is proposed.
DIY Activists Communities of Practice, Cultural Dialogism, and Radical Knowledge Sharing

This study explored innovative alternative processes of living, learning, and knowledge sharing of a loosely knit community of anarchist, anticapitalist “Do-It-Yourself” (DIY) activists. Generated ...
Complications of carotid endarterectomy and their prevention.

Mortality and morbidity associated with carotid endarterectomy may be minimized by proper selection of patients and proper operative and postoperative management. Complications include cardiac and airway problems related to anesthesia, infection, hematoma, nerve pareses, parotitis, arterial disruption, false aneurysms, and carotid-cavernous fistula. The most serious complication is the occurrence of neurologic deficits as a result of cerebral emboli or ischemia. Emboli are due to excessive manipulation of the artery, while ischemia results from hypotension, intracerebral thrombosis, or inadequate cerebral protection. Adequacy of collateral blood flow during carotid clamping is determined by temporary occlusion under local anesthesia, measurement of internal carotid artery stump pressure, or EEG monitoring. The most reliable method of cerebral protection is a temporary inlying shunt. Selective shunting is used if the patient is intolerant of temporary clamping, if stump pressure is below 55 mm Hg, or if EEG changes occur. For maximum safety, the author suggests routine shunting and general anesthesia. Operative mortality for patients experiencing transient ischemic attacks should be less than 1% and operation-related neurologic deficits no more than 2%. Meticulous attention to technical details is obligatory. Hypotension should be avoided during and after operation to avert thrombosis, and excessive hypertension postoperatively must be treated promptly to avoid cerebral hemorrhage and edema. Operation is contraindicated on patients with acute profound and progressing strokes.
Dynamic phenomena in the visible layers of sunspots

The empirical properties of the various dynamic phenomena are reviewed and interrelated with emphasis on recent observational results. The topics covered are: 1. Introduction 2. Aperiodic Phenomena 2.1. Externally Driven Phenomena 2.1.1. Umbral Flares 2.1.2. Inverse Evershed Flow 2.2. Internally Driven Phenomena 2.2.1 Penumbra 2.2.1.1. Penumbral Grains 2.2.1.2. Evershed Flow 2.2.2. Umbra 2.2.2.1. Umbral Dots 2.2.2.2. Inhomogeneity of the Umbral Magnetic Field 2.2.2.3. Umbral Turbulence 3. Oscillations and Waves 3.1. Chromosphere 3.1.1. Umbra: Oscillations and Flashes 3.1.2. Penumbra: Running Waves and Dark Puffs 3.2. Photosphere 4. Overview
δ13C values of soil organic matter in semiarid grassland with mesquite (Prosopis) encroachment in southeastern Arizona

Over the past century, C3 woody plants and trees have increased in abundance in many semiarid ecosystems, displacing native C4 grasses. Livestock grazing, climatic fluctuations, and fire suppression are several reasons proposed for this shift. Soil carbon isotopic signatures are an ideal technique to evaluate carbon turnover rates in such ecosystems. On the gunnery ranges of Fort Huachuca in southeastern Arizona, study sites were established on homogeneous granitic alluvium to investigate the effects of fire frequency on δ13C values in surface soil organic matter (SOM). These ranges have had no livestock grazing for 50 years and a well-documented history of fires. Prosopis velutina Woot. (mesquite) trees have altered SOM δ13C pools by the concentration of plant nutrients and the addition of isotopically light litter. These soil carbon changes do not extend beyond canopy margins. Elevated total organic carbon (TOC), plant nutrient (N and P) concentrations, and depleted SOM δ13C values are associated with C3 Prosopis on an unburned plot, which enables recognition of former Prosopis-occupied sites on plots with recent fire histories. Elevated nutrient concentrations associated with former Prosopis are retained in SOM for many decades. Surface SOM δ13C values indicate the estimated minimum turnover time of C4-derived carbon beneath large mature Prosopis is about 100–300 years. In contrast, complete turnover of original C3 carbon to C4 carbon under grasslands is estimated to take a minimum of 150–500 years. Our study confirms that C4 grass cover has declined over the past 100 years, although isolated C3 trees or shrubs were not uncommon on the historic C4-dominated grasslands. We find evidence in surface soil layers for a modern C3 plant expansion reflected in the substantial shift of SOM δ13C values from C4 grasses to C3 shrublands.
Isolation and characterization of mitochondrial alanine aminotransferase from porcine tissue.

Abstract Mitochondrial alanine aminotransferase l -alanine:2-oxoglutarate amino-transferase, EC 2.6.1.2) has been isolated in homogeneous form from both porcine liver and kidney cortex, but in low yield. Polyacrylamide gel electrophoresis of the purified enzyme in the presence of sodium dodecyl sulfate or 8 M urea gave a single band. An isoelectric point of 8.5 ± 0.5 and a molecular weight of 75–80 000 were obtained. The enzyme is specific for l -alanine and is inhibited by d -alanine, aminooxyacetate and cyclosterine. The K m for pyruvate and glutamate is 0.4 mM and 32 mM, respectively. These values are similar to those determined for the cytoplasmic enzyme; however, at high concentrations, both compounds strongly inhibit the mitochondrial enzyme, an inhibition not observed with cytosolic alanine aminotransferase. These characteristics and the fact that the mitochondrial alanine aminotransferase was inactivated by procedures effective in the preparation of the cytosolic enzymes, clearly differentiate the two proteins and further support different roles for the two alanine aminotransferases in vivo.
Effect of hypercholesterolemia on the hemoglobin-oxygen dissociation curve of the rabbit.

Abstract We have investigated the effect of hypercholesterolemia on the oxygen—hemoglobin dissociation curve and oxygen—hemoglobin kinetics of rabbits. Hypercholesterolemia was induced with a high-fat diet. The p 50 value of the oxygen dissociation curve was determined before and after the diet and showed no change. Uptake and release rates of oxygen by erythrocytes were also measured before and after a high-cholesterol diet. There was no significant change in the rates following the induction of hypercholesterolemia. Our findings, contrary to those of others, do not show any effect of hypercholesterolemia on hemoglobin—oxygen kinetics in rabbits.
LiveLab: measuring wireless networks and smartphone users in the field

We present LiveLab, a methodology to measure real-world smartphone usage and wireless networks with a reprogrammable indevice logger designed for long-term user studies. We discuss the challenges of privacy protection and power impact in LiveLab and offer our solutions. We present an iPhone 3GS based deployment of LiveLab with 25 users intended for one year. Early results from the data collection so far highlight the unique strengths and potential of LiveLab. We have two objectives in this position paper. First, we demonstrate the feasibility and capability of LiveLab. By sharing our experience, we seek to advocate LiveLab as a network and user measurement methodology. Second, we present our preliminary findings, and seek feedback from the community regarding what data to collect.
The relation of parental attitudes to academic and social achievement in epileptic children.

SUMMARY Parental attitudes were correlated with several variables relative to academic and social achievement in 54 epileptic children. Those attitudes found to be significantly correlated with social development involved strictness in child-rearing practices. Academic achievement was significantly correlated with parental acceptance of activity. Socialization was the aspect of development which correlated to the greatest extent with parental attitudes. Frequency of seizures was negatively correlated with social development but was not correlated with academic achievement. Type of seizure was not significantly correlated with either academic achievement or social development. RESUME L'attitude des parents etait en relation avec plusieurs facteurs concernant le succes scolaire et social. La facon d'elever les enfants avec rigueur, etait en relation significative avec le developpement social. Le succes scolaire etait en relation significative avec l'acceptation des parents, d'une libre activite de l'enfant. La socialisation etait l'aspect du developpement qui etait le plus lie avec l'attitude des parents. La frequence des crises etait en relation negative avec le developpement social, mais n'etait pas en relation avec le succes scolaire. Le type des crises n'etait pas en correlation significative ni avec le succes scolaire, ni avec le developpement social.
Pathways to life success: A conceptual model of financial well-being for young adults

The purpose of this study is to describe and test a conceptual model of the potential antecedents and consequences of financial well-being in young adulthood. Data (N = 781) were collected via an online survey conducted at a large state university in the southwestern United States. Our results suggest that self-actualizing personal values, financial education at home, and formal financial education at school may play important anticipatory socialization roles in the ways that young adults acquire knowledge about financial matters and form attitudes and behavioral intentions based on that knowledge. These financial domains, along with parental normative expectations and young adults' perceived behavioral control, were related to their financial well-being, which was in turn related to academic success and overall life satisfaction, as well as psychological and physical health. Theoretical and applied implications are provided.
Crossing the Midline as a Function of Distance from Midline

This study examined the effect of differential block placement on the frequency of midline crossing during the Space Visualization test (SV) of the Southern California Sensory Integration Tests. The SV test was administered at distances of 0.75, 3.00, and 6.00 inches to a group of 71 normal right-handed boys (ages 5 and 7 years) to obtain the Space Visualization Contralateral Use score (SVCU) and the Space Visualization Contralateral Use Percentage score (SVCU percent). Space Visualization (SV) adjusted scores were also obtained to examine the effect of differential block placement on visual perception scores. The analyses for the SVCU and SVCU percent scores showed that age and distance were significant. Analysis of variance of the SV adjusted standard score indicated that trial, but not distance or age, was significant. There was a significant age-by-trial interaction. The need for a standard protocol for block placement during the administration of the SV test was shown. Future research needs were identified.
Neural network target tracker

Real-time visual tracking is a difficult problem requiring high speed processing. We have previously reported a fast tracking algorithm (the Line Correlator Tracker (LCT) )12 capable of estimating displacement for a sequence of images using a conventional rectangular sensor. When used with a logarithmic-spiral sensor3, changes of scale can also be estimated. Although the algorithm can be implemented using sequential or parallel digital processing, a Hopfield-Tank (HT) network implementation is potentially simpler and faster.
Stimulation of Tyrosine Phosphorylation of a Brain Protein by Hibernation

Mammalian hibernation is a state of natural tolerance to severely decreased brain blood flow. As protein tyrosine phosphorylation is believed to be involved in the development of resistance to potentially cell-damaging insults, we used immunoblotting for the phosphotyrosine moiety to analyze extracts from various tissues of hibernating and nonhibernating ground squirrels. A single, hibernation-specific phosphoprotein was detected in the brain, but not in any other tissue tested. This protein, designated pp98 to reflect its apparent molecular weight, is distributed throughout the brain, and is associated with the cellular membrane fraction. The presence of the protein is tightly linked to the hibernation state; it is not present in contemporaneously assayed animals that are exposed to the same cold temperature as the hibernators, is present for the duration of a hibernation bout (tested from 1 to 14 days), and disappears within 1 hour of arousal from hibernation. The close association of pp98 with the hibernation state, its presence in cellular membranes, and the known properties of membrane phosphotyrosine proteins suggest that it may transduce a signal for adaptation to the limited availability of oxygen and glucose and low cellular temperature that characterizes hibernation in the ground squirrel.
Introductions and extinction of fish in the African great lakes

The great lakes of Africa contain one of the most remarkable known examples of rapid evolution and speciation of a vertebrate group. The three major lakes - Lake Victoria, Lake Malawi and Lake Tanganyika - each contain a unique radiation of fish belonging to the family Cichlidae. This has produced species 'flocks' that are unique to each lake in species numbers and diversity. At present most of the cichlid species in Lake Victoria are facing extinction as a result of the introduction of an exotic fish species. There are many other examples of introductions or invasions of non-native fish that have had severe effects on the native fish populations and regional economics. These examples should provide a clear warning against the proposed introductions of exotic fish into Lake Malawi.
"Orthotopic" ossiculum terminale persistens and atlantoaxial instability in a child less than 12 years of age: a case report and review of the literature

We report ossiculum terminale persistens associated with atlantoaxial instability in a child less than 12 years of age. Static and dynamic X-rays, thin-cut computed tomography with sagittal and coronal reconstructions, and magnetic resonance imaging of the cervical spine showed atlantoaxial instability and an "orthotopic" ossiculum terminale persistens. This pathologic state was differentiated from the primary ossification center at the tip of the odontoid, which normally is not expected to fuse with the body of the odontoid until the age of 12 years. The patient was taken to the operating room for a posterior instrumented fusion of C1 and C2. The patient has done well in short- and long-term follow-up. There have been only a few case reports and small case series regarding atlantoaxial instability, requiring surgical intervention, from ossiculum terminale persistens. Most have presented later in life or in association with Down syndrome. Furthermore, most cases have been of the "dystopic" variant. The terms - "orthotopic" and "dystopic" anatomic variants - have usually been reserved to describe os odontoideum. However, we introduce these terms in describing ossiculum terminale persistens and show a rare case of "orthotopic" ossiculum terminale persistens associated with atlantoaxial instability in a pediatric patient less than the age of 12.
Effects of UVA (320-400 nm) on the barrier characteristics of the skin.

The stratum corneum serves as the major barrier to the entrance of most molecules into the skin. In the studies presented here, the effects of UVA radiation (320-400 nm) on the barrier capacity of human stratum corneum were examined. Penetration of a homologous series of primary alcohols through unirradiated (control) and UVA-irradiated (test) human epidermis was determined in vitro Permeability constants, kp, were calculated. Mean ratios of permeability constants for UVA-irradiated and unirradiated epidermis (mean kp test)/(mean kp control) ranged from 2.3 to 3 0 for methanol and from 2.2 to 2.5 for ethanol. These mean ratios were determined using different pieces of epidermis from the same piece of skin for test and control samples. When kp control and kp test were determined on the same piece of epidermis on successive days, the ratios (kp test/kp control) were similar to the mean ratios determined on different pieces of epidermis. For other primary alcohols, propanol, butanol, hexanol, and heptanol, UVA radiation did not alter their permeability constants significantly Partition coefficients, Km, were determined for ethanol and heptanol using UVA-irradiated and unirradiated stratum corneum. For ethanol, irradiation resulted in a 1.5 to 2.6 times increase in Km. For heptanol, irradiation caused no change in Km. These results demonstrate that the barrier capacity of stratum corneum for small, polar, primary alcohols is diminished (permeability increases) and for higher molecular weight less polar alcohols, is re affected by small doses of UVA radiation. This increased permeability of small polar alcohols through human skin may be due to enhanced partitioning into UVA-irradiated stratum corneum, which was not apparent for a higher molecular weight less polar alcohol.
Violence and HIV-related risk among young men who have sex with men.

Abstract Limited research has been conducted on threats or violence by family members and sexual partners against young men who have sex with men (MSM). Young MSM, aged 15–22 years, who attended public venues in New York City were enrolled in an anonymous, cross-sectional HIV seroprevalence and risk-behavior study. About two-thirds (68%) of the young MSM reported ever experiencing threats or violence from either family or partners and 25% reported threats or violence by both family and partners. In multivariate analysis, threats or violence by partners was significantly associated with older age, a history of forced sex and a history of running away from home. Recent unprotected anal sex and club drug use were significantly associated with a history of threats or violence by both family and partners. HIV prevention interventions need to include multiple factors that may have an impact on risk, including substance use and abuse, anti-violence and other mental-health issues.
Diffusion tensor imaging of normal brain development

Diffusion tensor imaging (DTI) is an MRI technique that can measure the macroscopic structural organization in brain tissues. DTI has been shown to provide information complementary to relaxation-based MRI about the changes in the brain’s microstructure. In the pediatric population, DTI enables quantitative observation of the maturation process of white matter structures. Its ability to delineate various brain structures during developmental stages makes it an effective tool with which to characterize both the normal and abnormal anatomy of the developing brain. This review will highlight the advantages, as well as the common technical pitfalls of pediatric DTI. In addition, image quantification strategies for various DTI-derived parameters and the normal brain developmental changes associated with these parameters are discussed.
A study of two-phase flow characteristics using reactor noise techniques

Abstract Recent work at the University of Washington has demonstrated the potential for studying two-phase flow characteristics using neutron noise techniques. This method offers the advantage of measuring global characteristics of two phase phenomenon without disturbing the flow or requiring large numbers of sensors. Not only can the presence of the injected air into the flow loops be seen in the neutron spectrum but also the neutron spectrum reflects the type of flow by producing a characteristic signature.
The photocatalytic oxidation of sulfur-containing organic compounds using cadmium sulfide and the effect on CdS photocorrosion

Abstract The photocatalytic oxidation of sulfur-containing compounds using cadmium sulfide was examined. The reaction rate is approximately zero-order with respect to organic concentration and is greatest under basic conditions. Both of these results are consistent with a rate dependence on the concentration of adsorbed substrate on the photocatalyst surface. Supporting electrolyte type and concentration have little effect on the reaction rate. The presence of sulfur-containing organics reduces the photo-corrosion of CdS.
Expression and Characterization of Human Pancreatic Preprocarboxypeptidase A1 and Preprocarboxypeptidase A2

Abstract We are investigating the potential utility of human carboxypeptidases A in antibody-directed enzyme prodrug therapy (ADEPT). Hybridization screening of a human pancreatic cDNA library with cDNA probes that encoded either rat carboxypeptidase A1 (rCPA1) or carboxypeptidase A2 (rCPA2) was used to clone the human prepro-CPA homologs. After expression of the respective pro-hCPA cDNA inSaccharomyces cerevisiae,the enzymes were purified to homogeneity by a combination of hydrophobic and ion-exchange chromatography. Purified hCPA1 and hCPA2 migrate as a single protein band withMr34,000 when subjected to gel electrophoresis in the presence of sodium dodecyl sulfate under reducing conditions. Kinetic studies of the purified enzymes with hippuryl- L -phenylalanine resulted inkcat/Kmvalues of 57,000 and 19,000 M −1s−1for hCPA1 and hCPA2, respectively. Using the ester substrate, hippuryl- D , L -phenyllactate, we found unique esterase/peptidase specific activity ratios among hCPA1, hCPA2, rCPA1, and bovine CPA (bCPA) ranging from 13 to 325. Two potential ADEPT substrates, methotrexate–α-phenylalanine (MTX-Phe) and methotrexate–α-(1-naphthyl)alanine (MTX-naphthylAla) were also analyzed. Thekcat/Kmvalues for MTX-Phe were 440,000 and 90,000 M −1s−1for hCPA1 and hCPA2, respectively, and for MTX-naphthylAla these values were 1400 and 1,400,000 M −1s−1for hCPA1 and hCPA2, respectively. The kinetic data show that hCPA2 has a larger substrate binding site than the hCPA1 enzyme. Differences between hCPA1 and hCPA2 were also observed in thermal stability experiments at 60°C where the half-life for thermal denaturation of hCPA2 is eightfold longer than that for hCPA1. These experiments indicate that hCPA1 and hCPA2 are potential candidates for use in a human-based ADEPT approach.
Saturable metabolism and its relationship to toxicity

Metabolism plays a central role in regulating the toxicity of a variety of chemicals. Relatively innocuous substances can be converted to highly toxic metabolites. Conversely, toxic substances can be biotransformed to less harmful metabolites or be excreted, thus limiting their duration of biological action. Virtually all metabolism and many excretory processes utilize specific binding proteins, i.e., enzymes and carrier proteins. These metabolic and carrier-mediated excretory clearance pathways are capacity-limited, becoming saturated at sufficiently high substrate concentrations. Saturable metabolic clearance processes lead to dose-dependent pharmacokinetics for many chemicals. When dose-dependent pharmacokinetics prevail, internally significant parameters, such as area under the curve for concentration of toxicant at active sites and the amount of metabolite formed during inhalation exposure, are not linearly related to externally significant parameters such as administered dose or inspired concentration. Dose-response curves should relate observed effects to some internally significant parameter. Toxic response should often be indexed to area under the curve relationships or total amount metabolized, instead of dose or inspired concentration. The former parameters are complexly related to the latter. The nature of the relationship depends on the kinetic constants for metabolic and excretory clearance. Pharmacokinetic analyses of dose-dependent clearance mechanisms provide an understanding of how one transforms externally significant parameters to internally significant parameters under various exposure conditions. Consideration of metabolic clearance at the organ level illuminates the importance of physiological factors, showing unequivocally that blood flow may be rate-limiting for metabolism under many exposure conditions. Recognition of the potential for this behavior is essential to the proper design and evaluation of certain toxicological experimentation. Development of comprehensive pharmacokinetic descriptions of the influence of saturable clearance on delivery of active chemical to target sites augurs well for improving both intraspecies and interspecies extrapolation of toxicity data. This is a critical area of contemporary toxicology. Dose selection for chronic studies could also be improved by knowledge of the dose-dependence of pharmacokinetic parameters in proposed test species. The field of toxicology reviewed here represents an interface between pharmacokinetic research and studies on basic mechanisms of toxic action. It entails utilization of quantitative concepts to better understand the physiological and biochemical controls which regulate the expression of the toxicity of various chemicals. Much work remains to be accomplished in this exciting area of toxicological research. Some of the predictions of the pharmacokinetic analyses are still tentative and require more definitive experimentation...
Class size and college students' evaluations of teachers and courses: A closer look

A systematic analysis of extant studies reveals, on average, a very weak inverse association between the size of class enrollment in a college course and students' overall evaluation of the course and its teacher, as well as between class size and evaluations of specific instructional dimensions pertaining to the instructor's skill in presenting material and communicating information. Larger inverse associations are typically found between class size and evaluations of specific instructional dimensions pertaining to the instructor's interactions and interrelationships with students. This pattern of findings is consistent with the accumulating evidence that the instructional dimensions of the first set have greater importance for students in forming their global opinions of teachers and courses than do those of the second set. The further finding in some studies of a negative curvilinear (roughly U-shaped) relationship between class size and evaluations is noted and discussed. Implications for the validity of teacher evaluations are considered and the related question of whether class size “biases” these evaluations is explored.
Apparent Coexistent Valvular and Subvalvular Left Ventricular Outflow Tract Obstruction

A patient is presented in whom coexisting bicuspid valvular aortic stenosis and asymmetrical septal hypertrophy were suggested by echocardiography. A focal area of hypertrophy noted at operation was excised. Subsequent histological examination did not reveal evidence to support the echographic and surgical observations. The necessity for careful intraoperative assessment of the degree and nature of subvalvular muscular hypertrophy is stressed. The absence of classic echographic findings in these patients is noted.
Abnormal protein translocation as the elusive cause of cystic fibrosis: an hypothesis

Despite the recent rapid advances in isolation of the abnormal gene responsible for cystic fibrosis, there remains the need to explain the mechanism by which a single gene mutation causes the widespread clinical effects seen in this disease. Careful review of the otherwise unexplained abnormalities of cystic fibrosis from the perspective of cell biology reveals the following common features: (1) all these abnormalities involve proteins which are either (A) inserted into cell membranes in the RER and arrested after partial translocation or (B) inserted into RER membranes and fully translocated to be compartmentalized away from the cytosol in secretory vacuoles, lysosomes or peroxisomes; (2) all the involved proteins have minor abnormalities in their physicochemical properties or activity functions; (3) none of the involved proteins are missing or totally deficient in function; (4) final compartmentalization of the involved proteins is unaffected. These observations have directed our attention to the process by which most proteins are inserted into and translocated across lipid bilayer membranes, namely the signal peptide mechanism. This mechanism, not previously examined in cystic fibrosis, is reviewed in detail. Of the major proteins controlling signal peptide translocation, deficiencies in the function of signal peptidase activity appear most capable of causing the effects seen in cystic fibrosis.
Gauge/gravity duality and jets in strongly coupled plasma

Abstract We discuss jets in strongly coupled N = 4 supersymmetric Yang-Mills plasma and their dual gravitational description.
A test for correlations among fitness-linked behavioural traits in the spider Agelenopsis aperta (Araneae, Agelenidae)

Abstract Abstract. The spider Agelenopsis aperta, exhibits a suite of behavioural traits that are functionally dissimilar but which all potentially could be influenced by inherent levels of 'fear' and 'aggression': agonistic behaviour, territory size, foraging behaviour, and anti-predatory behaviour. Previous findings suggest that in A. aperta, agonistic behaviour and territory size are phenotypically correlated at both the individual and population levels, as are foraging and anti-predator behaviour patterns. In this study first anti-predatory and then agonistic trials were completed on two sets of spiders (wild and laboratory-reared F1 generation) from each of two populations (desert grassland and riparian) to test for an inter-connection between these two sets of traits. Spider scores in the anti-predatory fear test were an accurate predictor of the outcome of contests between individuals that were matched for weight but that had different fear scores. This entire set of traits may have the same underlying genetic basis as pleiotropic effects of the same genes. However, quantitative genetic studies are required to test this hypothesis.
Cyclic Adenosine and Guanosine Monophosphates and Glucagon: Effect on Liver Membrane Potentials

Cyclic adenosine monophosphate, cyclic guanosine monophosphate, glucagon, and isoproterenol each hyperpolarized perfused rat liver cells. The hyperpolarization followed a time course similar to the stimulated increase in potassium efflux and was preceded by the increase in calcium efflux. The hyperpolarization induced by cyclic adenosine monophosphate was blocked by tetracaine. The similarity of the action of the cyclic nucleotides to that of glucagon supports the hypothesis that cyclic adenosine monophosphate is the secondary messenger mediating the action of glucagon.
Voter turnout and candidate choice: A merged theory

An alternative approach to the explanation of voting behavior is offered, suggesting that the starting point of electoral decision making is individuals' recall of their behavior in the last similar situation. Whether or not this recall is accurate is irrelevant in our model, since the voters' reasoning proceeds from their belief about their earlier behavior, whether or not it is correct. Using this approach we are able to treat voting from a unified perspective, rather than adopting the current stance of treating the turnout decision as separate from and preceding the candidate choice decision.