cssi/SciSciGPT-SciSciNet huggingface dataset:
Validation on the Europa Clipper Mission in the Formulation Phase

The Europa Clipper mission will perform a detailed investigation of Europa's environment and habitability by placing a spacecraft into a looping orbit around Jupiter and performing repeated close Europa flybys. The Europa Clipper Project Verification and Validation (V&V) team is responsible for verifying that the Project System is compliant with the science and engineering requirements levied on it and validating that it is capable of meeting the mission objectives. Europa Clipper has developed a V&V framework to ensure that mission capabilities are realized at a reasonable confidence level prior to launch. The V&V team will coordinate the validation activities defined by this framework throughout the project lifecycle as the spacecraft evolves from design to implementation and operations. Validation of space missions is typically grouped into three categories: 1) requirements validation, 2) model validation, and 3) system validation. System validation, along with verification activities, are often the primary focus of V&V programs and these efforts peak in the implementation phase. However, the increasing reliance of exploration missions on models and simulations, and the complexity of the Europa Clipper mission, have dictated attention to requirements and model validation in the formulation phase. This paper discusses the development of the Europa Clipper V&V framework with emphasis on the validation of models and simulations, and of requirements. Approaches include the adaptation of institutional guidelines, such as those in the NASA-STD-7009 document, to create a Project Model V&V Plan and the use of tools such as DOORS NG to plan model validation and derive requirement quality metrics.
From Grading to Assessment for Learning: A Qualitative Study of Student Perceptions Surrounding Elimination of Core Clerkship Grades and Enhanced Formative Feedback

Problem: Medical students perceive honors grading during core clerkships as unfair and inequitable, and negatively impacting their learning and wellbeing. Eliminating honors grading, a powerful extrinsic motivator, and emphasizing formative feedback may address these problems and promote intrinsic motivation and learning. However, it is unknown how transitioning from honors to pass/fail grading with enhanced formative feedback in the core clerkship year may affect student learning experiences, wellbeing, and perceptions of the learning environment. Intervention: Core clerkship grading was transitioned from honors/pass/fail to pass/fail at one US medical school. In addition, the requirement for students to obtain formative supervisor feedback was formalized to twice per week. Context: This qualitative study utilized semi-structured interviews to explore the perceptions among core clerkship students of learning and assessment. Interview questions addressed motivation, wellbeing, learning behaviors, team dynamics, feedback, and student and supervisor attitudes regarding assessment changes. The authors analyzed data inductively using thematic analysis informed by sensitizing concepts related to theories of motivation (goal orientation theory and self-determination theory). Impact: Eighteen students participated, including five with experience in both honors-eligible and pass/fail clerkships. The authors identified three major themes in students' descriptions of the change in approach to assessment: student engagement in clerkships, wellbeing, and recognition of learning context. Student engagement subthemes included intrinsic motivation for patient care rather than performing; sense of agency over learning, including ability to set learning priorities, seek and receive feedback, take learning risks, and disagree with supervisors, and collaborative relationships with peers and team members. Positive wellbeing was characterized by low stress, sense of authenticity with team members, prioritized physical health, and attention to personal life. Learning context subthemes included recognition of variability of clerkship contexts with pass/fail grading mitigating fairness and equity concerns, support of the grading change from residents and some attendings, and implications surrounding future stress and residency selection. Lessons Learned: Students perceive a transition from honors grading to pass/fail with increased feedback as supporting their engagement in learning, intrinsic motivation, and wellbeing. Drivers of wellbeing appear to include students' feelings of control, achieved through the ability to seek learning opportunities, teaching, and constructive feedback without the perceived need to focus on impressing others. Ongoing evaluation of the consequences of this shift in assessment is needed.
Report of the 1st International Electronic Conference on Toxins (IECT2021), 16-31 January 2021.

The 1st International Electronic Conference on Toxins (IECT2021) was successfully held online by https://sciforum [...]
Probing the Edges between Stability and Degradation of a Series of ZnSe-Based Layered Hybrid Semiconductors

The discovery of layered materials with potentially unique electrical and chemical properties has become a major focus of materials research in the past decade. II-VI layered hybrids (LHs) are a family of ligand-protected layered materials capable of isolation in few-layer form and possess emissive and electronic properties of potential relevance to semiconductor device technologies. We showed previously that, akin to black phosphorus (BP) and transition metal dichalcogenides (TMDCs), II-VI LHs are sensitive to ambient atmospheric conditions. However, the causes for degradation of these ligand-protected materials remain unclear. Using ZnSe-based LHs, we show herein that the stability of these materials is related to the length and chemistry of the organic ligands coordinated to the LH surfaces. Furthermore, exposure to isotopically enriched H218O and 18O2 reveals that H2O and O2 are both reactants contributing to ZnSe-LH degradation. An H2O-initiated degradation pathway is proposed and is supported by density functional theory (DFT) calculations. Our findings contribute to the discovery of protection strategies for layered materials and elucidate a degradation pathway that may also be applicable to other layered materials.
Life Cycle of Neurospora crassa Viewed by Scanning Electron Microscopy

Scanning electron microscopy was used to examine the major stages of the life cycle of two wild-type strains of Neurospora crassa Shear and Dodge (St. Lawrence 3.1a and 74A): mycelia, protoperithecium formation, perithecia, ascospores, ascospore germination and outgrowth, macro and microconidia, and germination and outgrowth of macroconidia. Structures seen at the limit of resolution of bright-field and phase-contrast microscopes, e.g., the ribbed surface of ascospores, are well resolved. New details of conidial development and surface structure are revealed. There appears to be only one distinguishable morphological difference between the two strains. The pattern of germination and outgrowth which seems relatively constant for strain 74A or strain 3.1a, appears to be different for each. Conidia from strain 3.1a almost always germinate from a site between interconidial attachment points; whereas the germ tubes of strain 74A usually emerge from or very near the interconidial attachment site. These germination patterns usually do not segregate 2:2 in asci dissected in order. This observation suggests that conidial germination pattern is not under the control of a single gene.
The trend toward online banking services by brick-and-mortar institutions: the last five years

Five hundred financial institutions in the United States were randomly sampled each year for five consecutive years in order to examine Internet participation, both evident at the time of the survey and planned by the selected financial institutions. Each year the selected institutions were surveyed regarding the existing involvement of their institution with online banking and that institution's Internet plans for the following two-year period. This study examines changes over time in the responses of the surveyed institutions. The results show that, over the study period, the percent of respondents that had or planned an Internet present within two years of the survey increased from 52% in 1996 to over 90% in 2000, and that the number of online services offered to customers is increasing.
Loss of efficiency in regression analysis due to irrelevant variables: A generalization☆

Abstract This note extends the specification error analysis of irrelevant variables in a regression model. It is shown that the loss of efficiency in estimating relevant regression coefficient is directly related to the magnitudes of the canonical correlations between the sets of relevant and irrelevant variables.
The antidepressant-like effect of the melatonin receptor ligand luzindole in mice during forced swimming requires expression of MT2 but not MT1 melatonin receptors.

We previously reported an antidepressant-like effect in C3H/HeN mice during the forced swimming test (FST) following treatment with the MT 1 /MT 2 melatonin receptor ligand, luzindole. This study investigated the role melatonin receptors (MT 1 and/or MT 2 ) may play in the effect of luzindole in the FST using C3H/HeN mice with a genetic deletion of either MT 1 (MTIKO) or MT 2 (MT 2 KO) melatonin receptors. In the light phase (ZT 9-11), luzindole (30 mg/kg, i.p.) significantly decreased immobility during swimming in both wild type (WT) (135.6 ± 25.3 s, n = 7) and MTIKO (132.6 ± 13.3 s, n = 8) as compared with vehicle-treated mice (WT: 207.1 ± 6.0 s, n = 7; MT 1 KO: 209.5 ± 6.2 s, n = 8) (P < 0.001). In the dark phase (ZT 20-22), luzindole also decreased time of immobility in both WT (89.5 ± 13.9 s, n = 8) and MT 1 KO (66.5 ± 6.4 s, n = 8) mice as compared with the vehicle treated (WT: 193.8 ± 3.5, n = 6; MT 1 KO: 176.6 ± 6.2 s, n = 8) (P < 0.001). Genetic disruption of the MT 1 gene did not alter the diurnal rhythm of serum melatonin in MTIKO mice (ZT 9-11: 1.3 ± 0.6 pg/mL, n = 7; ZT 20-22: 10.3 ± 1.1 pg/mL, n = 8) as compared with WT (ZT 9-11: 1.4 ± 0.7 pg/mL; ZT 20-22: 10.6 pg/mL). Swimming did not alter the serum melatonin diurnal rhythm in WT and MTIKO mice. Decreases in immobility of WT and MTIKO mice by luzindole treatment were not affected by gender or age (3 months versus 8 months). In contrast, luzindole did not decrease immobility during the FST in MT 2 KO mice. We conclude that the antidepressant-like effect of luzindole may be mediated through blockade of MT 2 rather than MT 1 melatonin receptors.
Algorithms for path radiance and attenuation to provide color-corrections for underwater imagery, characterize optical properties and determine bottom albedo

There is growing interest in the development and utilization of optical instrumentation to measure water properties of coastal waters for ground-truthing satellite data. Current methods for determining above-water remote-sensing reflectance assume vertical homogeneity in the water column. In cases where in-water vertical structure and bottom reflectance confound standard algorithms, new methods must be developed to incorporate inhomogeneities. This paper addresses the available avenues for characterizing optical properties, color-correcting underwater imagery and determining bottom albedo values. The method begins by deriving backscatter from remote-sensing reflectance data collected near the red end of the visible spectrum near the surface where bottom reflectance is negligible and path radiance is maximal. Measured upwelling radiance is divided by measured downwelling irradiance yielding underwater remote sensing reflectance values. The backscattering coefficient is then modeled for each wavelength and the path radiance calculated and removed using measured attenuation coefficients. The above values are used to reduce the algorithm to an equation for bottom albedo by removing the bias associated with path radiance and the filter effects associated with the water path to and from the bottom. The calculated bottom reflectance is needed to interpret and correct above-water remote-sensing reflectance and satellite imagery. The results are illustrated using comparisons of color-corrected and non-color-corrected in-situ imagery of specific corals and their immediate surroundings. Imagery of a coral scene at various altitudes is also presented to illustrate spectral changes due to changes in thickness of the water column between the camera and the bottom.
TU-G-303-01: Radiomics: Quantitative Imaging in the Service of Improved Treatment Decision Making

‘Radiomics’ refers to studies that extract a large amount of quantitative information from medical imaging studies as a basis for characterizing a specific aspect of patient health. Radiomics models can be built to address a wide range of outcome predictions, clinical decisions, basic cancer biology, etc. For example, radiomics models can be built to predict the aggressiveness of an imaged cancer, cancer gene expression characteristics (radiogenomics), radiation therapy treatment response, etc. Technically, radiomics brings together quantitative imaging, computer vision/image processing, and machine learning. In this symposium, speakers will discuss approaches to radiomics investigations, including: longitudinal radiomics, radiomics combined with other biomarkers (‘pan-omics’), radiomics for various imaging modalities (CT, MRI, and PET), and the use of registered multi-modality imaging datasets as a basis for radiomics. There are many challenges to the eventual use of radiomics-derived methods in clinical practice, including: standardization and robustness of selected metrics, accruing the data required, building and validating the resulting models, registering longitudinal data that often involve significant patient changes, reliable automated cancer segmentation tools, etc. Despite the hurdles, results achieved so far indicate the tremendous potential of this general approach to quantifying and using data from medical images. Specific applications of radiomics to be presented in this symposium will include: the longitudinal analysis of patients with low-grade gliomas; automatic detection and assessment of patients with metastatic bone lesions; image-based monitoring of patients with growing lymph nodes; predicting radiotherapy outcomes using multi-modality radiomics; and studies relating radiomics with genomics in lung cancer and glioblastoma. Learning Objectives: 1. Understanding the basic image features that are often used in radiomic models. 2. Understanding requirements for reliable radiomic models, including robustness of metrics, adequate predictive accuracy, and generalizability. 3. Understanding the methodology behind radiomic-genomic (’radiogenomics’) correlations. Research supported by NIH (US), CIHR (Canada), and NSERC (Canada)
The Biology of Musical Performance and Performance-Related Injury by Alan H. D. Watson

The Biology of Musical Performance and Performance-Related Injury could be reviewed simply by saying that arguably it is the best book in its field yet to be published and therefore it is highly re...
Emergence of MCF-7 cells overexpressing a transfected epidermal growth factor receptor (EGFR) under estrogen-depleted conditions: Evidence for a role of EGFR in breast cancer growth and progression

Overexpression of epidermal growth factor receptor (EGFR) is correlated with loss of estrogen receptor and poor prognosis in breast cancer. To investigate this phenomenon, we transfected a cytomegalovirus expression vector directing the expression of EGFR into estrogen receptor-positive MCF-7 breast cancer cells and into a clone of MCF-7 cells previously transfected with transforming growth factor alpha. Cells arising from single clones or pooled polyclonal populations maintained in charcoal-stripped calf serum, a medium devoid of estrogen, overexpressed EGFR. Switching these cells to a medium containing fetal calf serum or charcoal-stripped calf serum plus 17 beta-estradiol resulted in the emergence of a population expressing low EGFR levels. Loss of expression was not a consequence of nonspecific repression of the cytomegalovirus promoter, because expression of the fibroblast growth factor (FGF)-4 complementary DNA in a similar vector was not lost in fetal calf serum. While loss of EGFR overexpression in fetal calf serum was seen at both the protein and mRNA levels, Southern blotting shows that this was not due to loss of the transfected gene. Subclones of a cell population with low EGFR expression were capable of increasing expression upon estrogen withdrawal, demonstrating that the changes in EGFR expression were reversible and suggesting a growth advantage conferred by EGFR overexpression under these restrictive growth conditions. Overexpression of EGFR did not result in loss of ER expression. These results suggest a role for overexpression of EGFR in the growth of estrogen receptor-positive breast cancer cells in the absence of estrogen.
Resection versus transplantation for hepatocellular carcinoma

Hepatocellular carcinoma is responsible for more than 1 million deaths per year worldwide and thus remains a challenging medical problem. It causes few or no symptoms and the tumour frequently reaches an enormous size by the time of diagnosis in countries where screening is seldom used. It is generally resistant to commercially available anti-neoplastic agents and radiation therapy. The principal treatment continues to be resection, either partial or complete, with liver transplantation. However, less than one-third of patients are surgical candidates for either resection or transplantation at the time of clinical presentation. This review will address the results observed following resection or transplantation for hepatocellular carcinoma.
Failure to achieve oxygen supplementation with hydrogen peroxide.

Hydrogen peroxide, administered rectally or intraperitoneally, has been reported to improve systemic oxygenation. Therefore, the effectiveness of intraperitoneal administration of hydrogen peroxide, 0.3%, was investigated in hypoxic rabbits as a possible method of supplementation of oxygenation in respiratory distress syndrome or in the postoperative cardiac patient. Although hydrogen peroxide initially caused a slight increase in arterial oxygen saturation, this increase was brief and was followed by a marked fall in arterial oxygen saturation. Hypotension occurred in all rabbits. It is suggested that the intraperitoneal administration of hydrogen peroxide for the purpose of extrapulmonary oxygenation is largely ineffective and hazardous, and it probably should not be attempted in the human subject.
Evidence for calcium channels in brine shrimp: diltiazem protects shrimp against cadmium.

Much information is available on the accumulation and effects of toxic substances in aquatic organisms (Malins & Ostrander 1991). Fewer studies, however, have examined toxic mechanisms in marine biosystems. Present experiments provide information on the mechanism by which cadmium penetrates into tissues of the small marine organism known as the brine shrimp. Brine shrimp are of major importance in the aquaculture industry and they have been proposed as a uniform world-wide test system for toxicity of chemical substances (Vanhaeke et al. 1981) and for studies in developmental toxicology (Sleet & Brendel 1985).
Predicting population dynamics and evolutionary trajectories based on performance evaluations in alife simulations

Evolutionary investigations are often very expensive in terms of the required computational resources and many general questions regarding the utility of a feature F of an agent (e.g., in competitive environments) or the likelihood of F evolving (or not evolving) are therefore typically difficult, if not practically impossible to answer. We propose and demonstrate in extensive simulations a methodology that allows us to answer such questions in setups where good predictors of performance in a task T are available. These predictors evaluate the performance of an agent kind A in a task T*, which can then transformed by including costs and additional factors to make predictions about the performance of A in T.
Interactions among Cells of the Developing Neural Retina in vitro1

Two models are presented for mechanisms leading to the formation of layers during the development of the chick neural retina. The first proposes that the different cells possessintrinsic characteristics that allow them to self sort into specific patterns. The second suggests that the cells migrate, or are moved, along a substrate which guides them into specific locations. Supporting evidence is presented for both hypotheses, suggesting that the overall process is highly complex, using elements of each mechanism.
The perils of polycentric governance of infectious disease in South Africa

In much of the developing world, a model of polycentric governance has become increasingly prevalent for the control of health and infectious disease - one in which a panoply of governance actors work concurrently on the same development projects, within the same localities. And yet, the question of whether polycentrism helps or hinders disease control/mitigation, or service provision more generally, has not been sufficiently studied. This article details findings from an exploratory case study of the polycentric governance of infectious disease in the Eastern Cape Province, South Africa. Combining analyses of an original survey of local councilors, structured interviews with relevant actors in four municipalities, and a national survey of South African citizens, the study finds a high degree of polycentric governance, and highlights associated accountability gaps and a series of constraints on effective service delivery. It concludes by identifying promising directions for future research.
Inverting waveforms for velocities in the presence of caustics

Transmission caustics cause velocity estimation techniques based on straightforward analysis of image volume moveout to fail. For example, the differential semblance objective function is smooth and quasi-convex when the incident wavefield is free of caustics, but loses these properties when caustics are present. The reason for this phenomenon is closely related to that identified by Geoltrain and Brac for the inadequacy of Kirchhoff migration based on first arrival times for complex velocity structure. controlled illumination of the subsurface, introduced by Rietvold and Berkhout to improve imaging, given an adequate macromodel, also suggests a new approach to image volume moveout analysis for macromodel estimation. In particular, the differential semblance objective function again becomes, through controlled illumination, a smooth quasi-convex function of the macromodel, hence suitable for optimization using variants of Newton's method. The transmission inversion problem provides a simple framework within which to illustrate the controlled illumination reformulation of differential semblance and its effectiveness.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
PREPARATION OF URANIA AND URANIA--ZIRCONIA MICROSPHERES BY A SOL-GEL PROCESS.

The sol-gel process was originally developed and applied at the Oak Ridge National Laboratory for preparation of high-density thoria-urania fragments and microspheres for nuclear reactor fuels. The application of the process for preparation of microspheres to sols of urania, urania-zirconia, and urania-carbon is reported in this paper. Relatively high-strength, spherical particles of UO2, UO2-ZrO2, and UC2 were prepared with diameters of 50-500 microns and densities of 80-100% of the theoretical densities. Le procede dit sol-gel a ete originairement mis au point et utilise au Laboratoire national d'Oak Ridge pour la preparation de fragments et de microspheres de thorine et d'urane pour les combustibles des reacteurs nucleaires. On rapporte dans le present travail l'application du dit procede servant a la preparation de microspheres a des sols d'urane-zircone et d'urane-carbone. On a prepare des particules spheriques d'UO2, UO2-ZrO2 et UC2 qui possedaient une resistance relativement elevee, des diametres de 50-500 microns et des densites atteignant 80 a 100% des valeurs theoriques.
Multistate impact-parameter calculation of atom-atom excitation cross sections - Excitation of atomic hydrogen by neon, argon, and krypton

Hydrogen and inert gas atoms collisional excitation cross sections calculated by multistate impact parameter approximation
Contrasting Effects of Conjugated Estrogens and Tamoxifen on Dilator Responses of Atherosclerotic Epicardial Coronary Arteries in Nonhuman Primates

Background Estrogens have been shown to improve dilator responses of atherosclerotic coronary arteries. Tamoxifen is a mixed estrogen agonist/antagonist with as yet unexplored effects on vascular function. Therefore, the goal of this study was to compare the effects of conjugated equine estrogens (CEEs) with those of tamoxifen on epicardial coronary artery dilator responses in atherosclerotic, ovariectomized monkeys. Methods and Results Fifty ovariectomized cynomolgus monkeys were fed an atherogenic diet for 34 months. During this time, monkeys were assigned to one of three treatment groups: (1) control, no hormone replacement (n=15); (2) CEEs mixed in the diet at a dose of 0.043 mg · kg−1 · d−1 (n=14); or (3) tamoxifen mixed in the diet at a dose of 1.3 mg · kg−1 · d−1 (n=21). Quantitative angiography was used to measure coronary artery dilator responses to intracoronary infusions of acetylcholine (10−8, 10−7, and 10−6 mol/L) and nitroglycerin (15 μg/min). Coronary arteries of the tamoxifen-treated group...
Deaths of Psychiatric Patients During Heat Waves

Deaths of patients in state psychiatric hospitals in the New York City area during heat waves and control periods from 1950 to 1984 were compared with those in the overall New York City population during the same periods. Psychiatric patients had twice the risk of dying during a heat wave than the general population. The risk for patients was higher in the 1950s, before the introduction of antipsychotic medications, than in the 1980s, but was highest in the 1970s, when higher dosages of antipsychotic medication were commonly used. During 1980 to 1984 the risk was the same for both populations, suggesting that both psychiatric illness and antipsychotic medications increase patients' risk of dying during heat waves but that risk can be eliminated with preventive measures.
The Costs Of Mental Health Parity: Still An Impediment?

Parity in mental health benefits rectifies unfairness in health insurance coverage and reduces financial risk for those with mental illness. However, increased coverage for mental illness has been seen as creating inefficiencies and increasing total spending, based largely on results from the RAND Health Insurance Experiment conducted in the 1970s. Newer evidence suggests that cost control techniques associated with managed care give health plans alternatives to discriminatory coverage for containing costs. We review both eras of research on mental health insurance and conclude that comprehensive parity implemented in the context of managed care would have little impact on total spending.
Practicing Politics with Foucault and Kant: Toward a Critical Life

This paper problematizes the claim that Michel Foucault's work is normatively lacking and therefore possesses only limited political relevance. While Foucault does not articulate a traditional normative framework for political activity, I argue that his work nonetheless reflects certain normative commitments to, for example, practicing freedom and improving the state of the world. I elucidate these commitments by sketching out Foucault's notion of critique as a mode of existence characterized by practices of the self, arguing that such practices possess political significance within the context of what Foucault refers to as a way of life, and analyzing points of intersection and departure between Kant's and Foucault's respective responses to the question `What is Enlightenment?' in order to clarify the connection Foucault makes between self-practices and freedom. Through this analysis I also show that Foucault reconceptualizes normative concepts such as obligation, freedom, autonomy and publicity in non-n...
Effect of steam sterilization of soil on trace metal toxicity in bush beans

Abstract Bush beans (Phaseolus vulgaris L. cv. Improved Tender green) were grown in steam sterilized soils and in caitrol soils with and without added Ni, Cd, and Cu. The objective was to determine if steam sterilization had interaction with the availability of trace metals to plants. The increased availability of Mn and possibly Cu to plants following sterilization depressed uptake of at least Ni and resulted in yield improvement. Steam sterilization increased Mo uptake by plants.
Use of ≥ 1 antihypertensive drug at bedtime reduced CV events more than use of all drugs in the morning in CKD

Source Citation Hermida RC, Ayala DE, Mojon A, Fernandez JR. Bedtime dosing of antihypertensive medications reduces cardiovascular risk in CKD. J Am Soc Nephrol. 2011;22:2313-21. 22025630
Who's in STEM? An Exploration of Race, Ethnicity, and Citizenship Reporting in a Federal Education Dataset

As the United States becomes more racially and ethnically diverse and draws more students from across the globe, more representative data are needed to understand at-risk and underrepresented populations in higher education, particularly in the science, technology, engineering, and mathematics (STEM) fields. The authors argue that the current reporting standards for the Integrated Postsecondary Education Data System (IPEDS) result in the misrepresentation of racial and ethnic populations in STEM by forcing non-U.S. students into a “master status” category regardless of their racial or ethnic group membership. This study uses data from IPEDS and the American Community Survey to estimate the possible misrepresentation of reported bachelor degree completions by racial and ethnic group and citizenship status in the biological and biomedical sciences and engineering. We found that nearly all of the racial and ethnic groups in IPEDS may be significantly misreported because of the reporting standards for U.S. ci...
Serotonin depletion induced by reserpine is attenuated by prophylactic administration of lithium

Abstract Prophylactic administration of lithium significantly attenuated the serotonin depleting effects reserpine. In rat brain, lithium did not change the capacity of the storage protein, serotonin binding protein to bind the amine either in vivo or in vitro nor did it change its sensitivity to reserpine. However, the chronic administration of lithium significantly decreased reserpine levels in plasma and brain tissue of treated rats compared with rats which were treated only with reserpine. It is concluded that the antagonism between reserpine and lithium does not involve the serotonin binding protein but may be due to the lithium-induced reduction of reserpine levels.
IUdR polymers for combined continuous low‐dose rate and high‐dose rate sensitization of experimental human malignant gliomas

SUMMARY Local polymeric delivery enhances IUdR radiosensitization of human malignant gliomas (MG). The combined low-dose rate (LDR) (0.03 Gy/h) and fractionated high-dose rate (HDR) treatments result in cures of experimental MGs. To enhance efficacy, we combined polymeric IUdR delivery, LDR, and HDR for treatments of both subcutaneous and intracranial MGs. In vitro: Cells (U251 MG) were trypsinized and replated in triplicate 1 day prior to LDR irradiation in media either without (control) or with 10 µM IUdR. After 72 hr, LDR irradiation cells were acutely irradiated (1.1 Gy/min) with increasing (0, 1.25, 2.5, 5.0, or 10 Gy) single doses. Implantable IUdR polymers [(poly(bis(p-carboxyphenoxy)-propane) (PCPP): sebaic acid (PCPP:SA), 20:80] (50% loading; 10 mg) were synthesized. In vivo: For flank vs. intracranial tumors, mice ha d6◊1 0 6 subcutaneous vs .2◊1 0 5 intracranial cells. For intracranial or subcutaneous MGs, mice had intratumoral blank (empty) vs. IUdR polymer treatments. One day after implantation, mice had immediate external LDR (3 cGy/h ◊ 3 days total body irradiation) or HDR (2 Gy BID ◊ 4 days to tumor site) or concurrent treatments. For the in vitro IUdR treatments, LDR resulted in a striking increase in cell-killing when combined with HDR. For the in vivo LDR treatments of flank tumors, the growth delay was greater for the IUdR vs. blank polymer treatments. For the combined LDR and HDR, the IUdR treatments resulted in a dramatic decrease in tumor volumes. On day 60 the log V/V0 were ˛1.7 ± 0.22 for combined LDR + HDR + IUdR polymer (P < 0.05 vs. combined LDR + HDR + blank polymer). Survival for the intracranial controls was 22.9 ± 1.2 days. For the blank polymer + LDR vs. blank polymer + LDR + HDR treatments, survival was 25.3 ± 1.7 (P = NS) vs. 48.1 ± 3.5 days (P < 0.05). For IUdR polymer + LDR treatment survival was 27.3 ± 2.3 days (P = NS). The most striking improvement in survival followed the IUdR polymer + LDR + HDR treatment: 66.0 + 6.4 days (P < 0.05 vs. blank polymer + LDR + HDR). The polymeric IUdR delivery plus combined continuous LDR and HDR treatments results in growth delay and improved survival in animals bearing the MG xenografts. This treatment may hold promise for the treatment of human MGs. © 2001 Wiley-Liss, Inc.
Dehalogenation of polymers prepared by atom transfer radical polymerization

Polymers prepared by atom transfer radical polymerization (ATRP) have well-defined end groups, predetermined by the initiator used. A typical initiator is an alkyl halide from which the halogen is transferred to one chain end. To remove the halogen end group, dehalogenation with trialkyltin hydride has been used. Procedures for the removal of the polymer halogen end groups are described, one of them being a one-pot reaction where the dehalogenation of the polymer chain ends occurs immediately after polymerization.
Smooth cocycles for an irrational rotation

Explicit examples of smooth cocycles not cohomologous to constants are constructed. Necessary and sufficient conditions on the irrational numberθ are given for the existence of such cocycles. It is shown that, depending onθ, the set ofCr cocycles whose skew-product is ergodic is either residual or empty.
Laterality in avian vigilance: do sparrows have a favourite eye?

Visual scanning for predators is one of a bird's most basic means of avoiding predation while feeding, and the detection of an approaching predator may present a difficult visual task. If birds have a dominant hemisphere for processing visual information, then given the nearly complete optic nerve crossover in the avian brain, the eye contralateral to that dominant hemisphere should be favoured in antipredatory vigilance. In short, vigilant birds should have a favourite eye. We conducted an experiment that examined laterality in eye use during the antipredatory scanning of wintering emberizid sparrows: dark-eyed juncos, Junco hyemalis, and American tree sparrows, Spizella arborea. Free-living birds were allowed to feed parallel to a visual obstruction, thereby forcing them to choose which eye to orient away from the visual obstruction and towards possible approaching predators. Juncos oriented themselves such that their right eye was oriented outward more than would be expected by chance. Tree sparrows had a marginally nonsignificant tendency to favour the left eye. The mechanics of the scanning process itself in these birds favoured one eye over the other. Both species turned their heads towards the visual obstruction when their preferred eye was facing away from the obstruction more often than would be expected by chance (right eye in juncos, left eye in tree sparrows); such behaviour allowed for a preferred-eye view of the area directly opposite protective cover. These results suggest that laterality exists in avian vigilance, and that laterality may differ even in closely related species.
Dynamic System Analysis for Electrical Power Systems

This paper analyzes the rotating rectifier type aircraft generator system so that a digital computer study of system transient response may be made. A detailed analysis of the generator is made using Park's equations. This analysis results in a mathematical model which is quite easily handled by a digital computer. A single time constant transfer function is used for the exciter-rectifier which has proved sufficiently accurate. The generator analysis could be extended to the exciter and rectifier equations derived in Reference 3 used to obtain better accuracy if sufficient exciter-rectifier data is available. The regulator transfer function is a ratio of polynomials with limits and constants furnished by the designer. The purpose of this paper is to present the detailed generator analysis and briefly discuss the methods of representing other system elements and the computer program used for problem solution.
Intravenous gestational nicotine exposure results in increased motivation for sucrose reward in adult rat offspring

Background Prenatal tobacco smoke exposure is associated with alterations in motivated behavior in offspring, such as increased consumption of highly palatable foods and abused drugs. Animal models show that gestational nicotine (GN) exposure mediates changes in responding for sucrose and drug reward.
The Presidential Term

Is there a relation between security returns and the year of a U.S. president9s term? The answer is yes. There is a prominent pattern in stock returns that relates to the presidential term. Equities have generally prospered in the second half of a president9s term, especially during the third year. Further analysis reveals that monetary policy actions correspond with the identified return pattern—Fed policy has generally been significantly more accommodative during the third year of a president9s term. The evidence overall strongly suggests that investors should carefully monitor the actions of policymakers and the political calendar before they make investment decisions.
Barrier Function at HMR

Summary The silenced HMR domain is restricted from spreading by barrier elements, and the right barrier is a unique t-RNA THR gene. We show that sequences immediately flanking the silenced domain were enriched in acetylated, but not methylated, histones, whereas the barrier element was associated with a nucleosome-free region. Surprisingly, the SAGA acetyltransferase resided across the entire region. We further demonstrate that a mutation in the barrier eliminated the nucleosome-free gap but only subtly altered the distribution of SAGA. Interestingly, neither reformation of the nucleosome nor mutations in chromatin-modifying enzymes alone led to an unrestricted spread of silenced chromatin. Double mutations in the t-RNA barrier and these complexes, on the other hand, led to a significant spread of Sir proteins. These results suggest two overlapping mechanisms function to restrict the spread of silencing: one of which involves a DNA binding element, whereas the other mechanism involves specific chromatin-modifying activities.
Agreement without understanding? The case of third person singular /s/

This study examined the comprehension of third person singular /s/ as a number agreement marker in children speaking Mainstream American English (MAE). Sixty-two MAE-speaking children aged 3-6 years were presented with a comprehension task where they had to focus on the verb as a clue to number agreement. Overall, results showed that only the 5- and 6-year olds were sensitive to third person singular /s/ as an index of subject number in comprehension, despite their earlier command in production. The implications for development of agreement are discussed.
Sticky Dollars: Inertia in the Evolution of Federal Allocations for HIV Care through the Ryan White HIV/AIDS Program

While substantial research examines the dynamics prompting policy adoption, few studies have assessed whether enacted policies are modified to meet distributional equity concerns. Past research suggests that important forces limit such adaptation, termed here “policy inertia.” We examine whether block grant allocations to states from the Ryan White HIV/AIDS Program have evolved in response to major technological and political changes. We assess the impact of initial allocations on later funding patterns, compared to five counterfactual distributional equity standards. Initial allocations strongly predict future allocations; in comparison, the standards are weak predictors, suggesting the importance of policy inertia. Our methodology of employing multiple measures of equity as a counterfactual to policy inertia can be used to evaluate the adaptability of federalist programs in other domains.
Impact of food on the pharmacokinetics and electrocardiographic effects of sustained release verapamil in normal subjects.

Abstract To evaluate the impact of food on the pharmacokinetics and electrocardiographic effects of sustained release (SR) verapamil tablets, 9 healthy men each received 3 single doses of verapamil in a randomized, crossover manner: 10 mg of intravenous verapamil, 240 mg SR verapamil on an empty stomach, and 240 mg SR verapamil with a standardized meal. PR intervals and racemic verapamil serum concentrations were measured serially over 30 hours after administration. The time to peak concentration was longer (7.5 ± 3.0 vs 4.4 ± 2.3 hours), resulting in a lower peak verapamil serum concentration (118 ± 43 vs 175 ± 50 ng/ml) when SR verapamil was administered with food (p
Ouabain‐ and Ca2+‐sensitive ATPase activity of chimeric Na‐ and Ca‐pump molecules

Chimeric ion-pumps, consisting of the N-terminal 23 of the α1-subunit of the ouabain-sensitive chicken Na+, K+-ATPase and the C-terminal 13 of the sarcoplasmic reticulum Ca2+-ATPase, were expressed in ouabain-insensitive mouse L cells. These chimeric molecules exhibited ouabain-sensitive ATPase activity very similar to that of the wild-type chicken Na+ K+-ATPase. This ATPase activity could be stimulated by adding Ca2+ to the assay system. These results suggest that the sites for ouabain-inhibition are restricted to the N-terminal 23 of the Na-pump, and the C-terminal 13 of the Ca-pump interacts with Ca3+.
High-power mid- and far- wavelength infrared lasers for free space communication

Laser-based free-space communications have been developed to serve specific roles in "last mile" high-speed data networks due to their high security, low cost, portability, and high bandwidth. Conventional free-space systems based on near infrared optical devices suffer from reliability problems due to atmospheric scattering losses and scintillation effects, such as those encountered with storms, dust, and fog. Mid-infrared wavelengths are less affected by atmospheric effects and can significantly enhance link uptime and range. This paper will discuss some of the recent advances in high-power, high temperature, high reliability mid-infrared Quantum Cascade Lasers and their potential application in highly reliable free space communication links.
G1 phase-dependent bcl-2 expression correlates with chemoresistance of human cancer cells1

Abstract Recent experiments suggest an interconnection between cell proliferation and programmed cell death (apoptosis) although the detailed molecular mechanisms remain unclear. We hypothesized that (i) some apoptosis regulators are periodically expressed during the cell cycle progression, and (ii) if so, cellular response to chemotherapeutic agents should be cell cycle-dependent. To test the first hypothesis, we synchronized multiple human tumor and transformed cell lines and measured protein levels of the cell death inhibitor Bcl-2 and inducer Bax in different phases of the cell cycle. In all the five tested cell lines, levels of Bcl-2 protein were very high in the G 1 phase, dramatically decreased in S, G 2 and M phase, and increased again in the G 1 phase of the next cycle. In contrast, levels of Bax protein remained relatively unchanged in most of the cell lines although S phase-associated Bax expression was detected in human breast carcinoma MCF-7 cells. Similar to its protein levels, Bcl-2 mRNA expression was also G 1 phase-specific, whereas the level of the Bcl-2 cleavage activity remained constitutive, indicating that cell cycle-dependent regulation of Bcl-2 is on its mRNA level. To test the second hypothesis, aliquots of the synchronized human tumor or transformed cells were treated with the anticancer drug etoposide or cisplatin, followed by measurement of apoptotic cell death. We demonstrated that the cells containing a high G 1 population and a high Bcl-2 protein level were much more resistant to chemotherapy-induced apoptosis than the cells containing a high S phase population and a low Bcl-2 protein level. Furthermore, constitutive overexpression of Bcl-2 protein in human Jurkat T cells partially inhibited the G 1 to S transition and completely blocked the S phase-associated chemosensitivity. Therefore, chemosensitivity and apoptotic commitment of human tumor cells are regulated by their cell cycle-dependent Bcl-p2 expression.
The positive diagnosis of neurotic depression as an etiological category.

Abstract In recent years, it became increasingly apparent that the cases to which the term “neurotic depression” was being applied were a mixed bag, some of which later turned out to be endogenous. This article shows that many of the nonendogenous depressions are neurotic depressions because they are secondary to learned maladaptive anxiety responses that are the core of neuroses. The experimental and clinical grounds for this view of neurosis are presented. Physiological studies have shown that neurotic depressions have high anxiety correlates in contrast to the low correlates of endogenous depressions. Clinically, there is evidence that the depressions associated with neurotic anxiety resolve lastingly when the anxiety is overcome by relearning methods that are selected on the assessment of the individual case, and without measures being taken against the depression as such. The recognition of a catagory of depressions due to neurotic anxiety should significantly enhance outcome research.
The EF-G-like GTPase Snu114p Regulates Spliceosome Dynamics Mediated by Brr2p, a DExD/H-box ATPase

Binding of a pre-mRNA substrate triggers spliceosome activation, whereas the release of the mRNA product triggers spliceosome disassembly. The mechanisms that underlie the regulation of these rearrangements remain unclear. We find evidence that the GTPase Snu114p mediates the regulation of spliceosome activation and disassembly. Specifically, both unwinding of U4/U6, required for spliceosome activation, and disassembly of the postsplicing U2/U6.U5.intron complex are repressed by Snu114p bound to GDP and derepressed by Snu114p bound to GTP or nonhydrolyzable GTP analogs. Further, similar to U4/U6 unwinding, spliceosome disassembly requires the DExD/H box ATPase Brr2p. Together, our data define a common mechanism for regulating and executing spliceosome activation and disassembly. Although sequence similarity with EF-G suggests Snu114p functions as a molecular motor, our findings indicate that Snu114p functions as a classic regulatory G protein. We propose that Snu114p serves as a signal-dependent switch that transduces signals to Brr2p to control spliceosome dynamics.
Achievable throughput in power-constrained cognitive wireless networks

Considering both spectrum underlay and opportunistic spectrum access scenarios in cognitive wireless networks, we seek to solve the following problem in this paper: Given that the secondary nodes have imposed upper limits on their transmission power levels to coexist with the primary network, what is the achievable throughput by the power-constrained secondary nodes? We first obtain statistics for some spatial properties in the secondary network, e.g., relative distances and angles between nodes. Assuming that the secondary transmitters choose the maximum permissible power level to coexist with a primary link and using the obtained spatial statistics, we find a lower bound for the throughput of secondary nodes by considering different forwarding models in the secondary network. We show that the approach is applicable for finding the achievable throughput in general power-constrained random wireless networks.