cssi/SciSciGPT-SciSciNet huggingface dataset:
Effect of laser dye deterioration on performance

A previous analysis that described loss of gain in a dye solution as a result of photochemical decomposition by pump photons is refined and is extended to the situation where impurities absorb at the pump wavelength. A limitation in the first paper is that it described only a single absorption depth in the medium at a constant pump fluxI p. The present examination includes the fall-off ofI p and integrates the total signal output with depth for a single-pass amplifier operated in the fully saturated gain condition. The equations are simpler, but as before loss of output, expressed in terms of a quantum yield of laser decayQ L, is minimized for a photochemically bleachable dye, and for one with high gain. Pumping in the vicinity of the absorption maximum is also advantageous.
Anin vacuo modal expansion method to determine the transient response of fluid-loaded planar vibrators

Abstract A general approach is presented to evaluate the vibratory response of fluid-loaded planar vibrators to broadband time dependent excitations for either radiation or scattering problems. The velocity of the vibrator is expressed as a sum of the products of thein vacuo modes and the time dependent modal velocities. In contrast to thein vacuo case, the modal velocities are coupled due to fluid loading. A set of coupled convolution integral equations for the time dependent modal velocities is developed and rearranged to facilitate their numerical solution. Analytical expressions are obtained for the impulse responses of thepc fluid-loaded admittances. These impulse responses which are the modal velocities when thepc or high-frequency approximation is made for the effect of fluid loading, are then used to compute the modal velocities when the effect of coupling is included. Since the known terms in the coupled convolution integral equations are very easily obtained, a large number of modes can be included in the analysis. Numerical results are presented to illustrate the effect of coupling on the velocity responses of simply supported plates to convecting line excitations and clamped circular plates to impacts.
A comparative study of the somato-axonal flow of protein in the feline hypoglossal and vagus nerves

After 3H-lysine was applied to the Xth and XIIth cranial nuclei, radioactive protein synthesized in the nerve cell bodies of the hypoglossal and vagus nerves moved down the axons of these fibers at maximal rates of 6.3±1.2 and 16±3 mm per day, respectively. The distribution of radiolabeled protein at various periods indicated that other proteinaceous components moved at slower velocities.
A Nocturnal Atmospheric Drainage Flow Simulation Investigating the Application of One-Dimensional Modeling and Current Turbulence Schemes

Abstract We developed a one-dimensional boundary layer model to simulate nocturnal atmospheric drainage flow on a simple forest-covered slope using canopy, soil and radiation parameterizations from previous studies along with turbulence simulation (from Mellor-Yamada) level three. A simulation of the drainage at Unit 19 of the ASCOT Geysers Project, 24 September 1980, is presented, from which we find that whatever horizontal flow-structure assumptions are made significantly affect the results through implied vertical advections. We recommend use of vertical-motion patterns obtained in relatively coarse two-dimensional simulations as a possible solution. Turbulence as simulated develops significant anisotrophy. Careful simulation of turbulence structure will require some reexamination of present turbulence modeling techniques. Nevertheless, using level three and assuming horizontal homogeneity, we were able to simulate well the mean profiles of wind and temperature at Unit 19 for one time when the ambient ...
Methylcobamide:Coenzyme M Methyltransferase Isozymes from Methanosarcina barkeri PHYSICOCHEMICAL CHARACTERIZATION, CLONING, SEQUENCE ANALYSIS, AND HETEROLOGOUS GENE EXPRESSION

A comparative study was made on the physicochemical characteristics of two isozymes of methylcobamide:- coenzyme M methyltransferase (MT2). Both isozymes catalyzed S-methylation of 2-thioethanesulfonate (coenzyme M) and exhibited similar apparent Km values for coenzyme M of 35 microM (MT2-A) and 20 microM (MT2-M). Weak binding to methylcobalamin was indicated by the apparent Km of 14 mM for both isozymes. Cob(I)alamin was established as the major product of the reaction, demonstrating heterolytic cleavage of the methylcobamide carbon-cobalt bond. The isozymes were shown to be zinc-containing metalloproteins. Metal ion chelators strongly inhibited both isozymes. A variety of coenzyme M analogs were tested for activity and/or inhibition. One alternative substrate 3-mercaptopropionate was discovered, with apparent Km 9 mM (MT2-A) and 10 mM (MT2-M). The results suggested an active site geometry in which coenzyme M is bound both by S-coordination to zinc, and electrostatic interaction of the sulfonate with a cationic group on the enzyme. Methanosarcina barkeri genes cmtA and cmtM encoding both isozymes were cloned and sequenced. Both genes encoded proteins with 339 amino acids and predicted molecular masses of 36-37 kDa. Active forms of both isozymes were expressed in Escherichia coli. A conserved segment with the potential for metal binding was found. The possibility of zinc involvement in catalysis of coenzyme M methylation is considered.
Wireless distributed computing in cognitive radio networks

Individual cognitive radio nodes in an ad-hoc cognitive radio network (CRN) have to perform complex data processing operations for several purposes, such as situational awareness and cognitive engine (CE) decision making. In an implementation point of view, each cognitive radio (CR) may not have the computational and power resources to perform these tasks by itself. In this paper, wireless distributed computing (WDC) is presented as a technology that enables multiple resource-constrained nodes to collaborate in computing complex tasks in a distributed manner. This approach has several benefits over the traditional approach of local computing, such as reduced energy and power consumption, reduced burden on the resources of individual nodes, and improved robustness. However, the benefits are negated by the communication overhead involved in WDC. This paper demonstrates the application of WDC to CRNs with the help of an example CE processing task. In addition, the paper analyzes the impact of the wireless environment on WDC scalability in homogeneous and heterogeneous environments. The paper also proposes a workload allocation scheme that utilizes a combination of stochastic optimization and decision-tree search approaches. The results show limitations in the scalability of WDC networks, mainly due to the communication overhead involved in sharing raw data pertaining to delegated computational tasks.
A CONVERSATION ON THE FUTURE OF BLACK POLITICS

This conversation, hosted by the Harvard Book Store and moderated by Rev. Eugene Rivers, took place in conjunction with the Boston Review 's (2012) forum on the power and potential of black movements. Featuring a lead article by Michael C. Dawson, the Future of Black Politics forum included responses from William Julius Wilson, Andra Gillespie, Tommie Shelby, Rev. Patrick H. O'Connor, Jennifer L. Hochschild, Lani Guinier and Gerald Torres, Dorian T. Warren, and Robin D. G. Kelley, with a reply by Michael C. Dawson. Here, the conversation continues.
Mechanisms of Pharmaceutical Aerosol Deposition in the Respiratory Tract

Aerosol delivery is noninvasive and is effective in much lower doses than required for oral administration. Currently, there are several types of therapeutic aerosol delivery systems, including the pressurized metered-dose inhaler, the dry powder inhaler, the medical nebulizer, the solution mist inhaler, and the nasal sprays. Both oral and nasal inhalation routes are used for the delivery of therapeutic aerosols. Following inhalation therapy, only a fraction of the dose reaches the expected target area. Knowledge of the amount of drug actually deposited is essential in designing the delivery system or devices to optimize the delivery efficiency to the targeted region of the respiratory tract. Aerosol deposition mechanisms in the human respiratory tract have been well studied. Prediction of pharmaceutical aerosol deposition using established lung deposition models has limited success primarily because they underestimated oropharyngeal deposition. Recent studies of oropharyngeal deposition of several drug delivery systems identify other factors associated with the delivery system that dominates the transport and deposition of the oropharyngeal region. Computational fluid dynamic simulation of the aerosol transport and deposition in the respiratory tract has provided important insight into these processes. Investigation of nasal spray deposition mechanisms is also discussed.
Dynamical symmetry breaking on a lattice

We propose to study dynamical symmetry breaking on a spatial lattice. Experiences with solid-state physics suggest that one should deal with an effective interaction between quarks and antiquarks rather than starting with the fundamental local Lagrangian. As an example, we study the ${(\overline{\ensuremath{\psi}}\ensuremath{\psi})}^{2}={(\ensuremath{\Sigma}{\ensuremath{\alpha}=1}^{N}{\overline{\ensuremath{\psi}}}_{\ensuremath{\alpha}}{\ensuremath{\psi}}_{\ensuremath{\alpha}})}^{2}$ interaction of massless fermions in two dimensions on a lattice in the approximation of a large number of degrees of freedom, $N$. We show explicitly that the model reduces to one-dimensional superconductivity by following the original methods of Bardeen, Cooper, and Schrieffer. The lattice coupling constant ${{g}_{0}}^{2}$ is found to go as $a$ for large lattice spacing $a$ and as $\ensuremath{-}\frac{1}{\mathrm{ln}a}$ for small $a$, and to have a finite cut for imaginary values of $a$. The same result may be obtained by a path-integral approach. For $N=1$ the model reduces to an antiferromagnetic chain.
Chronic pain: a multiple-setting comparison of patient characteristics.

Chronic pain patients attending four different pain management programs (N=160)were compared on multiple variables encompassing demographics, the nature of the pain problem, and treatment history. Programs were selected because they differed on several dimensions (e.g., geographic location, general hospitals vs those serving veterans of Armed Services, university affiliated vs nonaffiliated) believed potentially to interact with treatment outcome. Results indicated differences between hospital programs serving veterans and general hospital programs (serving nonveterans) in terms of patients' age, percentage married, disability compensation, duration of pain symptoms, and treatment history. In addition, findings indicated that covariance among pain variables was dissimilar across the four types of pain programs, making it difficult to generalize from one type of setting to another regarding issues such as choice of optimal treatment.
On the History of the Pony Express and Extending Its Operation into the Telegraph Era

The Pony Express was a horseback mail delivery endeavor that lasted from April 1860 until October 1861. The route extended from Saint Joseph, Missouri, to Sacramento, California, and then on to San Francisco, California, by boat. With letters sealed in a mail pouch, riders covered the 1,966-mi route in no more than 10 days. The fast pace was sustained by exchanging horses every 10 mi and riders every 75 to 100 mi. The Pony Express ceased operations amid huge financial losses and the completion of the transcontinental telegraph. This study reviews its history and asks whether a healthy, solvent Pony Express could have survived competition from the telegraph until completion of the transcontinental railroad in 1869. A trinomial logit model compares the probabilities of choosing between standard mail, Pony Express, and telegraph. Market shares of 96.5% for standard mail, 2% for telegraph, and 1.4% for Pony Express are estimated on the basis of their 1861 prices and other historical information. Lowering the ...
Social reward-conditioned place preference: A model revealing an interaction between cocaine and social context rewards in rats

A recent thrust in drug abuse research is the influence of social interactions on drug effects. Therefore, the present study examined conditioned place preference (CPP) as a model for assessing interactions between drug and social rewards in adolescent rats. Parameters for establishing social reward-CPP were examined, including the number of conditioning sessions/day (1 or 2), the total number of sessions (2, 8, or 16), and the duration of sessions (10 or 30 min). Subsequently, the effects of cocaine or dextromethorphan on social reward-CPP and play behavior were examined. The results demonstrate that social reward-CPP (i.e., preference shift for an environment paired previously with a rat) was similar using either 1 or 2 conditioning sessions/day and either 10 or 30 min sessions; however, social reward-CPP increased as the number of social pairings increased. Additionally, a low dose of cocaine (2 mg/kg, IP) and a low number of social pairings (2 pairings) failed to produce CPP when examined alone, but together produced a robust CPP, demonstrating an interaction between these rewards. The non-rewarding drug, dextromethorphan (30 mg/kg, IP), failed to enhance social reward-CPP, suggesting that drug-enhanced social reward-CPP is specific to rewarding drugs. Surprisingly, there was no relationship between play behaviors and preference shift in drug-naive animals. Furthermore, cocaine inhibited play behavior despite enhancing social reward-CPP, suggesting that aspects of social interaction other than play behavior likely contribute to social reward. The findings have important implications for understanding the influence of social context on cocaine reward during adolescence.
Is there a unique form of chromatin at the Saccharomyces cerevisiae centromeres

Chromosome transmission in S. cerevisiae requires the activities of many structural and regulatory proteins required for the replication, repair, recombination and segregation of chromosomal DNA, and co-ordination of the chromosome cycle with progression through cell cycle. An important structural domain on each chromosome is the kinetochore (centromere DNA and associated proteins), which provides the site of attachment of chromosomes to the spindle microtubules. Stoler et al. have recently reported the cloning of an essential gene CSE4, mutations in which cause chromosome nondisjunction of a marked chromosome bearing a centromere DNA mutation. The cse4-1 mutation causes cells to arrest in the G2/M phase of the cell cycle with a 2N DNA content in a RAD9 checkpoint-independent manner. The carboxyl terminus of Cse4p and the human centromere-localized protein CENP-A have a high degree of homology to the C-terminal domain of histone H3. Since both CENP-A and Cse4p also have biochemical properties similar to histones H3 and H4, it is tempting to speculate that these histone H3-like proteins are components of specialized nucleosomes, a class of which may be unique to the centromeres.
HLA and H2 class II transgenic mouse models to study susceptibility and protection in autoimmune thyroid disease.

Using single H2 and HLA class II transgenic mice, in the absence of endogenous H2 class II molecules, we have studied the permissiveness of class II molecules for experimental autoimmune thyroiditis (EAT). Resistant strains expressing susceptible class II molecules, H2Ak or HLA-DR3, developed EAT, clearly demonstrating the importance of class II gene inheritance. Polymorphism for HLA-DRB1 was observed, as DR3, but not DR2 or DR4, molecules were permissive for EAT induction with either mouse (m) or human (h) thyroglobulin (Tg). HLA-DQ polymorphism was also detectable, as hTg-induced EAT developed in DQ8+, but not DQ6+, mice. Class II gene interactions leading to reduced EAT severity were observed in H2 transgenic mice, when H2E transgene was expressed in H2A+ mice or H2A molecules were introduced into our novel H2A-E+ transgenic model. Similarly, in DR3+ mice, only the DQ8 transgene reduced EAT severity, depending on both background genes (C57BL/10 or NOD) and Tg species. Based on computer-predicted, class...
Pitch angle measurements from satellites using particle telescopes with multiple view directions

Abstract An analysis technique for obtaining spherical harmonic coefficients from multiple particle telescopes mounted with different viewing directions on a spinning spacecraft is presented. The coefficients and their standard deviations are obtained by the method of least squares. The relation of these coefficients to physically meaningful parameters is discussed. Applications of these techniques to data from instruments on two spacecraft are illustrated.
Controversies in the management of early-stage germ cell tumors

The optimal management of clinical stage I testicular germ cell tumors remains controversial despite a cure rate of 99%. Alternatives for stage I nonseminomas include close surveillance, retroperitoneal lymph node dissection, and chemotherapy. For pure seminomas, the options are surveillance, chemotherapy, and radiation. Understanding the pros and cons of each approach may help in choosing a management plan.
Spatial uniformity in diffusively-coupled systems using weighted L 2 norm contractions

We present conditions that guarantee spatial uniformity in diffusively-coupled systems. Diffusive coupling is a ubiquitous form of local interaction, arising in diverse areas including multiagent coordination and pattern formation in biochemical networks. The conditions we derive make use of the Jacobian matrix and Neumann eigenvalues of elliptic operators, and generalize and unify existing theory about asymptotic convergence of trajectories of reaction-diffusion partial differential equations as well as compartmental ordinary differential equations. We present numerical tests making use of linear matrix inequalities that may be used to certify these conditions. We discuss an example pertaining to electromechanical oscillators. The paper's main contributions are unified verifiable relaxed conditions that guarantee synchrony.
Differential Regulation of Rat Luteinizing Hormone α- and β-Subunits During the Stimulatory and Down-Regulatory Phases of Gonadotropin-Releasing Hormone Action*

Chronic treatment with agonist analogs of GnRH or long term continuous administration of GnRH results in down-regulation of pituitary LH secretion. We investigated the changes in the LH subunits during the stimulatory and down-regulatory phases of GnRH action in rat pituitary cell monolayer culture. The rat pituitary cells in culture, pretreated with medium alone or GnRH agonist for 48 h, were incubated with graded doses of GnRH for 4 h, and LH, LHα, and LHβ concentrations in the media and cell pellets were measured by specific and sensitive RIAs. Cells pretreated with medium alone responded to GnRH with a dose-dependent increase in LH, LHα, and LHβ immunoreactivity in the medium. However, rat LH, LHα, and LHβ concentrations in the cell pellets showed a dose-dependent decrease with GnRH treatment. Pretreatment with GnRH agonist led to a marked decrease in the LH response of cells to graded doses of GnRH. During this down-regulatory phase, the concentrations of LHβ in the medium remained undetectable even ...
Satellite Proximity Detection Using Multi-Function Space-Based Sensors

As countries enter into space programs, both low earth orbit (LEO) and geosynchronous earth orbit (GEO) satellites are increasingly subjected to an ever-increasing risk of collision with resident space objects. Sensors are becoming necessary to observe and measure the proximity of a satellite to determine the risks posed from kinetically approaching manmade and natural hazards. Volume, mass, and power on satellites is limited and risk management approaches tend to remove such sensors from satellite systems.With newer system engineering approaches, however, the traditional sensors used for navigation and measurement can be modified to sense the environment for hazards and obtain more information from what was previously a single function device.
Emergency and Critical Care Management of Acute Ischaemic Stroke

Ischaemic stroke is a devastating condition that is the leading cause of disability in the USA. Over the last 2 decades, the focus of management has shifted from secondary stroke prevention to acute treatment. Coordinated care starts in the field with the emergency medical service providers and continues in the ambulance and the emergency department through to the intensive care unit. After diagnosis and stabilization, a major goal is reperfusion therapy with intravenous fibrinolytics. Neuroimaging research is focused on improving patient selection, expanding treatment windows, and increasing the safety of therapeutic intervention. The role of adjunctive intra-arterial and mechanical thrombectomy remains undefined, and methods to improve reperfusion using sonolysis and new-generation fibrinolytics are currently investigational. Treatment in the intensive care unit targets prevention of secondary brain injury through optimization of blood pressure, cerebral perfusion, glucose, and temperature management, ventilation, and oxygenation. The most feared complications include malignant cerebral edema and symptomatic hemorrhagic transformation. Decompressive craniectomy is life saving, but questions regarding patient selection and timing remain. Hyperosmolar agents are currently used to mitigate cerebral edema, but newer agents to prevent the formation of cerebral edema at the molecular level are being studied. We outline a practical approach to current emergency and intensive care management based on consensus guidelines and the best available evidence.
A new species of Rhagovelia in the armata group from Belize (Heteroptera: Veliidae)

Rhagovelia chac n. sp. is described from the mountains of interior Belize. This species is morphologically similar to Rhagovelia planipes Gould, which occurs in the adjacent basal section of the Yucatan Peninsula. Figures of the male and female dorsal habitus and male genitalic structures are provided, accompanied by a distribution map and a photo of the type locality.
Metal removal by wetland mesocosms subjected to different hydroperiods

Abstract Scirpus californicus (giant bulrush) wetland mesocosms were subjected to four hydroperiods (pulsed-discharge regimes). The most frequently pulsed treatment (twice per day) was the most efficient at removing metals from synthetic wastewater. This was attributed to the formation of iron oxyhydroxides, which complex with the metals. The continuously flooded treatment had slightly lower removal rates. After a year of metal additions, mean removal efficiencies were 75–78% for cadmium, chromium, and zinc, 84% for lead, and 55% for mickel. Most of the metals were retained in the soil. The fine roots accumulated roughly 35% of the added cadmium, 6% of the copper, and 13% of the zinc. The shoots, rhizomes, and coarse roots each accumulated about 1% or less of the added metals. Indications are that wetland treatment, especially with hydroperiod manipulation, can reduce metal concentrations in wastewater and, therefore, in downstream ecosystems.
The Role of Conflict Resolution Styles in Mediating the Relationship Between Enduring Vulnerabilities and Marital Quality

This investigation examines the role of negative affectivity and conflict styles on newlywed couples' marital satisfaction. The vulnerability-stress-adaptation (VSA) model of marital development was used to explain relationships between enduring vulnerabilities, adaptive processes, and marital quality. Dyadic analyses and tests of mediation were performed on data from 194 couples in the first 5 years of their marriage. Results indicate that wives' negative affectivity is significantly associated with their own lower marital satisfaction and husbands' lower marital satisfaction. However, husbands' negative affectivity is only associated with their own lower marital satisfaction. For all spouses, negative affectivity was associated with a tendency to engage in more dysfunctional conflict styles. Tests of mediation indicate that positive problem solving, and to a lesser extent, conflict engagement, and withdrawal were able to partially explain the relationship between negative affectivity and marital quality...
Reduced CD4 and HLA-DR Expression in Neonatal Monocytes☆

Three-color flow cytometry was used to assess the immunophenotypic characteristics of normal cord blood monocytes after labeling with a variety of antibodies against myeloid/monocyte-specific markers. Monocytes both in cord blood and in peripheral blood from normal adults were defined in a backgating procedure as cells with the light-scattering characteristics of monocytes that also expressed CD14. The percentage of monocytes, defined in this fashion, that also displayed CD4 receptors was significantly lower in cord blood (mean ± SD = 29.3 ± 13.9%) than in peripheral blood from normal adult controls (mean ± SD = 68.9 ± 13%) (P< 0.005). Similarly, HLA-DR expression was found on only 86 ± 6.6% of monocytes in cord blood but on 99 ± 1% of monocytes in adults (P< 0.005). The percentage of monocytes displaying CD16 receptors in cord blood did not show any significant difference in comparison with adult monocytes. When coexpression of CD14, CD16, and CD4 was assessed, cord blood showed a predominant population of monocytes bearing the phenotype CD14+/CD16−/CD4−. Similarly, approximately 10% of CD14+ monocytes in cord blood expressed neither CD4 nor HLA-DR. Cytochemically, monocytes from cord blood revealed intense granular staining for PAS and marginal or absent staining for nonspecific esterase (NSE). These results raise the possibility that reduced expression of CD4 and HLA-DR receptors on cord blood monocytes may contribute to their impaired immune response. Additionally, the high percentage of CD14+/CD16−/CD4− cells in cord blood suggests that these cells may represent a phenotypically immature population of monocytes. Likewise, the unusual cytochemical staining patterns suggest that these cells are biochemically immature as well.
Natural Product Chemistry: From Plants to Human

Conventionally, natural product chemistry deals with the isolation, characterization, and synthesis of compounds from plants. It a broad sense, natural product chemistry may include all fields of biochemistry. Two projects are presented to illustrate the expanded definition of natural product chemistry. One deals with phosphatidylinositol (PI) and the key enzyme involved in its metabolism, PI-specific phospholipase C. The other project is on the structure-function relationship of human tumor suppressor p16.
Comparative sensitivity to gamma radiation of conidia, mycelia, and sglerotia of Botrytis cinerea

The multicellularity and indeterminate growth of fungus propagules, other than spores, preclude studies utilizing familiar bacteriological techniques in which surviving fractions of cell populations are determined. To compare the sensitivity to gamma radiation of conidia, mycelia, and sclerotia of Botrytis cinerea , an end-point technique was utilized in which the dose preventing postirradiation out-growth from 50 per cent of samples of various sizes was determined. Similar samples were utilized to determine dry-weights and contents of protein and DNA, each of which was used as a measure of sample size. Regardless of index of sample size utilized, young mycelia and sclerotia were more resistant and mature mycelia more sensitive than conidia.
Genetic differences in the time course for the development and persistence of the anticonvulsant effects of carbamazepine against cocaine seizures

Initial studies of the effect of chronic carbamazepine (CBZ) against cocaine-induced seizures indicated that there were genetic differences in both the time course for the development of the anticonvulsant effects of CBZ against cocaine-induced seizures and the persistence of these effects. The present studies were initiated to investigate the time course for the development and persistence of the anticonvulsant effects of chronic CBZ against cocaine seizures in BALB/cByJ, C57Bl/6J and SJL/J mice. The anticonvulsant actions of CBZ were dependent on the duration of CBZ administration, requiring 4-7 days to achieve maximal efficacy. However, once the anticonvulsant effects of CBZ were manifest, the effect persisted for up to 5 days after stopping CBZ treatment depending on the genotype. The levels of CBZ and its active epoxide metabolite were determined in plasma and brain at various time points during and after chronic CBZ treatment. The levels of CBZ and CBZ-10,11-epoxide were substantially reduced over the course of treatment in all three strains, such that the levels of the two compounds in plasma and brain could not account for the decreased susceptibility to cocaine seizures observed following chronic CBZ. These results suggest that the effects of CBZ on cocaine seizures are mediated by relatively long-term changes in one or more biological systems associated with cocaine's convulsant effects.
Discrimination reversal learning in the crayfish.

Summary Nine crayfish failed to show progressive improvement in learning over nine reversals in a two-choice spatial discrimination problem involving a non-correction procedure of training. The results are discussed in their relationship to the habit reversal data on other species.
Role of aminotransferases in glutamate metabolism of human erythrocytes.

Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from α-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional 1H–13C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis.
Macromolecular adduction by trichloroacetonitrile in the Fischer 344 rat following oral gavage

Abstract Male Fisher 344 rats were administered 1- or 2-[ 14 C]trichloroacetonitrile (TCAN) by oral gavage. DNA was isolated from the liver, kidneys and stomach and several protein fractions (globin, albumin and globulins) were isolated from blood. TCAN binds to both the DNa and the blood proteins in a dose-related manner. More radiolabel was associated with the DNA when the carbon at C 2 position was labeled, than at C 1 position. However, the position of the radiolabel did not influence the levels of radioactivity associated with the blood proteins. The stomach exhibited the highest level of DNa binding, followed in order by the liver and kidney. TCAN binding level was higher in DNA isolated from rats killed at 24 h than at 4 h after administration. In contrast, the three blood proteins showed similar binding levels, regardless of the exposure time. Radio-activity associated with DNA was not incorporated into the nitrogen bases (i.e. via de novo synthesis) and a covalent binding index (μmol chemical bound/mol nucleotide phosphate per mmol/kg body wt. of chemical administered) of 30–120 was observed for various tissues. Most of the radioactivity (60–80%) associated with globin could be released and separated from the protein by the treatment with concentrated ammonium hydroxide and precipitation of protein by organic solvent. Three peaks were observed in the HPLC elution profiles of the radioactivity released from the globin. Trichloroacetic acid co-eluted with one of these released products (peak II), however, the chemical identity of the material under the major peak (peak III) and peak I are still uncharacterized.
Fast GPU algorithms for endmember extraction from hyperspectral images

The N-FINDER algorithm is widely used for endmember extraction from hyperspectral images. One of the disadvantages of N-FINDER is that its sequential implementations have long run times due to their relatively large computational complexity. A fast parallel version of N-FINDER is developed in this paper. This version combined with the use of Hyperspectral Image Reduction for Endmember Extraction technique (HIREE) provides an algorithm that is 8 times faster than the original N-FINDER sequential algorithm.
Preparing Secondary Special Education Teachers to Be Collaborative Decision Makers and Reflective Practitioners: A Promising Practicum Model.

This study describes a practicum model for preparing secondary special education teachers consonant with the initiative to merge general and special education. The goal is to prepare teachers who are collaborative decision makers and reflective practitioners. In a 4-week intensive summer practicum, special education graduate students and middle school mathematics teachers designed and implemented two units of instruction in mathematics for at-risk and mildly handicapped youngsters. The experience was structured to engage graduate students in thinking seriously about the process of teaching and to examine the effects of their pedagogical decisions on learners. Data analyses revealed factors essential to the success of such practicum endeavors and captured changes in graduate students' reflective orientations.
Analysis of glutamate uptake and monosodium glutamate toxicity in neural retina monolayer cultures

Abstract Three different types of monolayer cultures from 8-day chick embryo neural retina can be generated by differential manipulation of culture media and substrata. They are: (i) a purified monolayer of neurons; (ii) a purified monolayer of nonneuronal, flat cells; and (iii) complex cultures containing both neurons and nonneurons. Autoradiographic studies showed that Na + -dependent, high affinity glutamate uptake occurs in about 30% of the neurons present in purified neuronal cultures, and in practically 100% of the flat cells in the purified nonneuronal monolayers or the complex cultures. These different culture preparations were used to investigate the well-known toxicity of monosodium glutamate (MSG) for retinal cells. Two different routes of administration were compared, namely: (i) in vivo preexposure of the embryos to MSG for 24 h, followed by dissociation and culture of the retina in MSG-free medium; and (ii) incorporation of MSG into the culture medium. MSG effects on flat cells were similar irrespective of the route used: flat cells showed a very dramatic reduction in number and a more spindle-like shape in MSG-treated cultures as compared with control cultures. The route of administration, however, had significant influence on the response of retinal neurons to MSG. After 3 days in vitro there were 50% fewer neurons in purified neuronal cultures when the cells were obtained from embryos pretreated in vivo with MSG than in controls, but there were no differences between controls and cultures exposed to MSG in vitro. However, MSG-containing medium preexposed for 30 min to a monolayer of nonneuronal flat cells became toxic for retinal neurons: purified retinal neurons exposed in vitro to this flat cell/MSG ‘conditioned medium’ showed a neuronal loss equivalent to that caused by an in vivo pretreatment with MSG. This observation is consistent with the hypothesis that MSG toxic effects on retinal neurons may be mediated by the nonneuronal cells. Autoradiographic studies showed that the total number of glutamate-labeled retinal neurons was similar in control cultures, in cultures from embryos pretreated in vivo with MSG and in cultures exposed in vitro to flat cell/MSG conditioned medium. This suggests that neurons with the capacity to take up glutamate via a high-affinity mechanism are not sensitive to the toxic effects of MSG.
Immunochemical detection of 5α-reductase in human serum

Abstract This study represents a continuing effort to find a new biomarker for the diagnosis and management of prostatic cancer. Polyclonal antibodies were prepared to a peptide (CAKP) representing amino acids 28 to 43 of the 5α-reductase type 2 isozyme. Using immunoaffinity-purified antibodies, the sera of 62 patients were examined by Western blot following polyacrylamide gel electrophoresis. A positive band was detected in the sera of several patients at 42 kDa compatible with the purified native glycosylated 5α-reductase type 2. These bands were nullified on coincubation of the antibody with the CAKP peptide. Analysis by high-performance liquid chromatography and amino acid sequencing by N-terminal Edman degradation of the immunoaffinity-purified antigen to the antipeptide antibodies of a patient with adenocarcinoma of the prostate suggests that the 5α-reductase type 2 isozyme may be linked to an immunoglobulin. An identical immunoaffinity-purified antigen to the CAKP peptide was isolated from a section of prostatic tissue from a different patient showing benign prostatic hypertrophy with severe dysplasia. It is suggested that an immunological response to the 5α-reductase type 2 isozyme was elicited in both instances.
Structural Damage Identification Using Assigned Partial Eigenstructure

A method of identifying damaged structural elements from measured modal data using an incomplete measurement set is presented. The method uses a mathematical optimization strategy to minimize deviations between measured and analytical modal frequencies and partial mode shapes. Damage is identified by determining the stiffness change to a finite element model required to match the measured data of the damaged structure. Damaged elements are obtained directly from the results of the cost-function minimization because the allowed structural changes are consistent with the original finite element formulation. The cost-function minimization is based on an assigned partial eigenstructure algorithm in which the physical properties of the structural elements are treated as control variables, which are chosen to achieve the measured partial eigenstructure. An iterative solution is used to solve the nonlinear optimization problem. Experimental results are reported for a cantilevered eight-bay truss assembly consisting of 104 elements.
Properties of hexagonal ScN versus wurtzite GaN and InN

Local-density approximation calculations are performed to compare properties of hexagonal ScN with those of wurtzite GaN and InN. A nearly five-times coordinated hexagonal structure is found to be (meta)stable in ScN, unlike the wurtzite structure. Structural, dielectric, and optical properties of this stable hexagonal phase are predicted to be rather different from those of wurtzite GaN and InN. This implies that disordered hexagonal ${\mathrm{Sc}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}\mathrm{N}$ and ${\mathrm{Sc}}_{1\ensuremath{-}x}{\mathrm{In}}_{x}\mathrm{N}$ alloys are very attractive both fundamentally and technologically.
Origins of hydrocarbons in Bering Sea sediments—I. Aliphatic hydrocarbons and fluorescence

Abstract Sixty-three samples from thirteen gravity cores were analyzed by GC/FID, qualitative GC/MS and fluorescence spectroscopy to determine the concentration, distribution and sources of hydrocarbons in Bering Sea sediments. Aliphatic hydrocarbons and fluorescence associated with aromatic compounds were detected in sediments at all locations. The sediments contain variable amounts of marine biological debris, terrigenous plant biowaxes, recycled continental material, petroleum and combustion derived hydrocarbons. Hydrocarbon concentrations were low and similar to previous reports from the Alaskan outer continental shelf (average UCM and total n -alkanes varied from 10.7 to 73.3 and 2.6 to 4.6 μg/g, respectively). Olefins, of a presumed biological origin, were widely distributed throughout Bering Sea sediments. The presence of a complete suite of normal alkanes, isoprenoids, an unresolved complex mixture, alkylated PAHs, and mature biological markers suggest that locations in the western and southern Bering Sea are contaminated with petroleum. This petroleum may be derived from natural seepage, recycled mature continental material, autochthonous exposed immature/mature sediments, and/or deposition of water column tarballs. The petroleum at one southern Bering Sea location is typical of a condensate and is significantly different from that observed at western Bering Sea locations. Vertical distributions and the presence of significant amounts of volatile hydrocarbons suggest that petroleum seepage is a likely source of contamination at these locations.
CD95 ligand expression on corneal epithelium and endothelium influences the fates of orthotopic and heterotopic corneal allografts in mice.

Purpose To determine the extent to which CD95 ligand (CD95L) expressed on corneal epithelium and endothelium influences survival of cornea grafts placed orthotopically and heterotopically in the anterior chamber (AC), an immune-privileged site. Methods Corneas from eyes of C57BL/6 (B6) and B6.gld (CD95L deficient) mice were (1) rendered into small full-thickness fragments, with or without an epithelial layer, and placed behind recipient corneas in the ACs of BALB/c eyes, while BALB/c corneas were similarly implanted in eyes of B6 and B6.lpr (CD95 deficient) mice; or (2) corneas were grafted orthotopically in BALB/c eyes as intact corneas or as composite corneas in which epithelium from one donor source was layered in vitro onto epithelium-deprived stroma+endothelium from another donor source before grafting. The fate of the grafts was assessed clinically and histologically, and the capacity of the grafts to sensitize recipient mice to donor alloantigens (delayed hypersensitivity, DH) was evaluated. Results Allogeneic, full-thickness B6.gld corneal fragment grafts placed in the AC of BALB/c mice were rejected and sensitized their recipients, whereas epithelium-deprived B6.gld cornea fragments survived indefinitely and failed to sensitize their recipients. BALB/c corneal fragment grafts placed in the AC of C57BL/6 or B6.lpr eyes were rejected. Orthotopic cornea grafts composed of B6.gld epithelium layered onto wild-type B6 stroma and endothelium were rejected at a tempo and incidence similar to full-thickness B6 grafts, whereas orthotopic composite cornea grafts containing B6 epithelium layered onto B6.gld stroma+endothelium were vigorously rejected. Conclusions CD95L expression on epithelium of full-thickness cornea fragment grafts placed in the anterior chamber of BALB/c eyes protects these heterotopic grafts from rejection but has only a trivial role to play in determining the fate of orthotopic corneal grafts. In the latter type of corneal grafts, CD95L expression on the endothelium plays an essential role in preventing graft rejection.
Functional effects of single nucleotide polymorphisms in the coding region of human N-acetyltransferase 1

Genetic variants of human N-acetyltransferase 1 (NAT1) are associated with cancer and birth defects. N- and O-acetyltransferase catalytic activities, Michaelis-Menten kinetic constants (K(m) and V(max)) and steady-state expression levels of NAT1-specific mRNA and protein were determined for the reference NAT1*4 and variant human NAT1 haplotypes possessing single nucleotide polymorphisms (SNPs) in the open reading frame. Although none of the SNPs caused a significant effect on steady-state levels of NAT1-specific mRNA, C97T(R33stop), C190T(R64W), C559T (R187stop) and A752T(D251V) each reduced NAT1 protein level and/or N- and O-acetyltransferase catalytic activities to levels below detection. G560A(R187Q) substantially reduced NAT1 protein level and catalytic activities and increased substrate K(m). The G445A(V149I), G459A(synonymous) and T640G(S214A) haplotype present in NAT1*11 significantly (P<0.05) increased NAT1 protein level and catalytic activity. Neither T21G(synonymous), T402C(synonymous), A613G(M205V), T777C(synonymous), G781A(E261K) nor A787G(I263V) significantly affected K(m), catalytic activity, mRNA or protein level. These results suggest heterogeneity among slow NAT1 acetylator phenotypes.
Fluctuation effects in mixed-valence systems at zero temperature

Abstract Experiments on mixed-valence compounds such as SmS are customarily interpreted by means of a model where the occupation of a given (4f) shell fluctuates in time with a characteristic period t, even at zero temperature. Such a classical viewpoint is logically not admissible for the stationary ground state of the system. We show, by means of simple and exactly soluble models, how Mossbauer and X-ray emission experiments can be interpreted without recourse to such a picture. The role of the final states in these experiments is essential.
Spinal analgesia: where is the evidence?

Dear Editor, We read with interest the systematic review by Myers and colleagues [1]. The authors conducted a thorough review of the literature on intraspinal techniques for pain management in cancer patients. They did a good job summarizing the existing studies and consensus. However, we would like to express our concerns regarding the authors' conclusions. Specifically, they stated in the abstract that “the evidence supported the use of intraspinal techniques for cancer pain management... Intraspinal techniques monitored by an interprofessional health care team should be included as part of a comprehensive cancer pain management program”. It is unclear how the authors arrived at these conclusions. The authors identified three randomized controlled trials comparing intraspinal with systemic analgesia [2–4]. The first study by Vanino et al. found no statistically significant difference in pain [2]; the second study by Smith et al. revealed a borderline statistical significance of questionable clinical value [3], while the third council study revealed no difference in pain control between epidural and subcutaneous administration of morphine [4]. The methodologic quality of the three included studies needs to be highlighted. Two studies reported no sample size calculations, and both appeared to be under-powered [2, 4]. Two were open-label studies [2, 3] which could significantly affect how pain and side effects were assessed. Finally, all were supported by pharmaceutical companies. It is known that industry support is an important source of bias in clinical trials [5, 6]. The authors also wrote in their discussion that “the main advantages of intraspinal analgesia for cancer pain are the delivery of adequate pain control and fewer side effects than with the conventional analgesia routes. Disadvantages of intraspinal analgesia include the technically demanding insertion procedure and close patient follow-up required by skilled healthcare personnel”. The authors may also want to emphasize the procedural risk and complications related the catheter and/or pump, such as infections, bleeding, and cerebrospinal fluid leak. The limited reporting of this important information could be potentially misleading. Based on these findings, perhaps the most appropriate conclusion is that the role of intraspinal opioids for the management of cancer pain has not been established and that adequately powered, well-designed, independently funded clinical trials are required before this complex, risky, and expensive intervention becomes part of routine care.