cssi/SciSciGPT-SciSciNet huggingface dataset:
VARIABLE THRESHOLD HETEROSTRUCTURE FET STUDIED BY MONTE CARLO SIMULATION

We investigate the influence on the performance of self-aligned n-type GaAs/AIGaAs Heterostructure Field Effect Transistors (HFETs) of using a threshold voltage that is allowed to vary with lateral position. We use a self-consistent ensemble Monte Carlo technique for this study of Variable Threshold HFETs (VTHFETs). For a gate length of 0.5 μm, we show that we are able to manipulate the velocity profile in the channel so as to increase the mean electron velocity in the source end of the channel by up to 50%. This figure also gives directly the improvement of the drain current and the transconductance. Despite this transconductance rise, the intrinsic cutoff frequency fT remains constant or even falls slightly. However, fT of a loaded device may still substantially increase.
Left ventricular hypertrophy is a possible biomarker for early mortality after type B aortic dissection.

Abstract Objective Data regarding the cardiac abnormalities associated with Stanford type B aortic dissection (TBAD) and whether these abnormalities are related to outcomes are limited. We describe the prevalence of cardiac abnormalities in patients with TBAD as detected by echocardiography. Methods This retrospective review included patients with TBAD presenting between 1990 and 2016. Echocardiograms performed within 6 weeks of acute TBAD were reviewed. Cardiac function, valve abnormalities, and stigmata of hypertensive heart disease including left ventricular hypertrophy (LVH) were ascertained. Characteristics of patients who did and did not receive echocardiograms were compared. Outcomes of patients with and without evidence of LVH on echocardiography were also compared. Results Of 239 patients with TBAD, 90 had echocardiograms performed within 6 weeks of acute TBAD (74% male; mean age, 57.8 ± 13.2 years). Echocardiograms were obtained at a median of 2 days (range, 0-41 days) from acute TBAD. Patients who had echocardiograms were more likely to present with malperfusion (28% vs 14%; P Conclusions LVH and other findings of hypertensive heart disease are common in patients with TBAD. LVH predicted all-cause mortality after TBAD in this small group of patients. Further exploration of the relationship between the chronic effects of hypertension and using LVH as an objective biomarker to risk stratify patients with TBAD and long-term outcomes after TBAD is warranted.
Temozolomide in Combination With NF-κB Inhibitor Significantly Disrupts the Glioblastoma Multiforme Spheroid Formation

Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor, accounting for 50% of all cases. GBM patients have a five-year survival rate of merely 5.6% and a median overall survival of 14.6 months with the “Stupp” regimen, 20.9 months with tumor treatment fields (TTF, OptuneR) in patients who participated in clinical trials, and 11 months for all GBM patients prior to TTF use. Objective: Our group recently developed a brain cancer chip which generates tumor spheroids, and provides large-scale assessments on the response of tumor cells to various concentrations and combinations of drugs. This platform could optimize the use of tumor samples derived from GBM patients to provide valuable insight on the tumor growth and responses to drug therapies. To minimize any sample loss in vitro , we improved our brain cancer chip system by adding an additional laminar flow distribution layer, which reduces sample loss during cell seeding and prevents spheroids from escaping from the microwells. Methods: In this study, we cultured 3D spheroids from GBM cell lines and patient-derived GBM cells in vitro , and investigated the effect of the combination of Temozolomide and nuclear factor-κB inhibitor on tumor growth. Results: Our study revealed that these drugs have synergistic effects in inhibiting spheroid formation when used in combination. Conclusions: These results suggest that the brain cancer chip enables large-scale, inexpensive and sample-effective drug screening to 3D cancer tumors in vitro , and could be applied to related tissue engineering drug screening studies.
Whose Citizenship? Social Conflict over Property in the United States

Land ownership and the rights in property are central to the American character, having originated as part of the colonial dialogue that led to the American revolution. Yet there has also been substantial social conflict over who has claims to property, and in whose interest. This article presents an interpretive history of citizenship claims to land and property from the colonial period to the present. It argues that a theme in this history is an ever expanding realm of citizenship claims against the individual owner, most markedly since the beginning of the twentieth century. The emergence of the modern environmental movement and a counter so-called private property rights movement in the 1970s forward has accentuated this social conflict. The future likely holds increased conflict in an era of social and political polarisation. The outcome is uncertain, and will depend on democratic dialogue among those with strongly opposing perspectives.
Analysis of Wikipedia pageviews to identify popular chemicals

A new approach to assess popularity relies on analysis of the number of times a web article is viewed. Here, a strategy is described to identify chemicals of widespread interest. The strategy makes use of Wikipedia, a rapidly growing publicly editable web encyclopedia that has become an influential knowledge base. While the total number of chemicals mentioned in Wikipedia is unknown, use of the Wikipedia Chemical Structure Explorer (WCSE) developed by Novartis enables identification of those that are described in an Infobox or Chembox along with a Simplified Molecular-Input Line-Entry system (SMILES) code. Using a Python script, all so-listed chemicals (16,243) in Wikipedia were identified and then sorted on the basis of their pageview rankings. Of the 16,243 chemicals, 846 (5.2%) belonged to controlled substances (United States Drug Enforcement Administration), WHO essential medicines, or the top 300 US drugs. These 846 chemicals received 220 million pageviews, which is 41.4% of the pageviews for all members of the Wikipedia chemical list. The number of chemicals described in the entire corpus of Wikipedia remains a tiny fraction of the <107 known chemicals. Much remains to be done to make the venerable literature and data of chemistry readily accessible. Regardless, identification of popular chemicals in this manner can be used to create selected databases, to tailor educational curricula, or to create targeted informational materials (such as safety brochures); such considerations of public demand are likely to engender corresponding widespread interest.
Electrochemical Reduction of [Ni(Mebpy)3]2+. Elucidation of the Redox Mechanism by Cyclic Voltammetry and Steady-State Voltammetry in Low Ionic Strength Solutions.

Bipyridine complexes of Ni are used as catalysts in a variety of reductive transformations. Here, the electroreduction of [Ni(Mebpy)3]2+ (Mebpy = 4,4’-dimethyl-2,2’-bipyridine) in dimethylformamide is reported, with the aim of determining the redox mechanism and oxidation states of products formed under well-controlled electrochemical conditions. Results from cyclic voltammetry, steady-state voltammetry (SSV) and chronoamperometry demonstrate that [Ni(Mebpy)3]2+ undergoes two sequential 1e reductions at closely separated potentials (E0’1 = -1.06 ± 0.01 V and E0’2 = -1.15 ± 0.01 V vs Ag/AgCl (3.4 M KCl)). Homogeneous comproportionation to generate [Ni(Mebpy)3]+ is demonstrated in SSV experiments in low ionic strength solutions. The comproportionation rate constant is determined to be > 106 M-1s-1, consistent with rapid outer-sphere electron transfer. Consequentially, on voltammetric time scales, the 2e reduction of [Ni(Mebpy)3]2+ results in formation of [Ni(Mebpy)3]1+ as the predominant species released into bulk solution. We also demonstrate that [Ni(Mebpy)3]0 slowly loses a Mebpy ligand (~10 s-1).
Capturing creative requirements via requirements reuse: A machine learning-based approach

Abstract The software industry has become increasingly competitive as we see multiple software serving the same domain and striving for customers. To that end, modern software needs to provide creative features to improve sustainability. To advance software creativity, research has proposed several techniques, including multi-day workshops involving experienced requirements analysts, and semi-automated tools to support creative thinking in a limited scope. Such approaches are either useful only for software with already rich issue tracking systems, or require substantial engagement from analysts with creative minds. In a recent work, we have demonstrated a novel framework that is beneficial for both novel and existing software and allows end-to-end automation promoting creativity. The framework reuses requirements from similar software freely available online, utilizes advanced natural language processing and machine learning techniques, and leverages the concept of requirement boilerplate to generate candidate creative requirements. An application of our framework on software domains: Antivirus, Web Browser, and File Sharing followed by a human subject evaluation have shown promising results. In this invited extension, we present further analysis for our research questions and report an additional evaluation by human subjects. The results exhibit the framework’s ability in generating creative features even for a relatively matured application domain, such as Web Browser, and provoking creative thinking among developers irrespective of their experience levels.
Law School Exams during a Pandemic – One Law School’s Experience

In 2020, toward the end of the Winter semester, the COVID-19 pandemic disrupted life across the globe. Institutions, including law schools, felt the widespread effects of this public health crisis. Law schools were forced to move entire curriculums online in record time and consider how they were going to administer final exams. There is no precedent or manual for how to do this successfully. The pressure of the high stakes law school final exam that the law student’s entire grade and ranking rest upon is stressful, to say the least. Law students are on edge during final exams during normal times, but as the United States became overwhelmed by the COVID-19 pandemic, universities sent students, faculty, and staff home to finish the semester online and were left with a myriad of issues to address. One issue that arose was how to deliver final exams in a completely online format while maintaining the integrity of the law school exam. This article discusses the pivot to flexibility that one law school had to make, under emergency conditions, and with limited resources. Part I describes the law school final exam pre-COVID 19, Part II describes the pre-planning process, Part III discusses the building process, Part IV discusses the administrating process, and Part V explores some of the lessons learned from the experience with exams and suggests how to move forward in an uncertain world.
Multistep Frequency Response Optimized Integrators and Their Application to Accelerating a Power System Transient Simulation Scheme.

This paper proposes several explicit and implicit multistep frequency response optimized integrators considering first or second order derivative. A prediction-based method aiming at accelerating a novel power system transient simulation scheme without impacting its accuracy is further put forward utilizing the proposed numerical integrators and some others available in the literature. Case studies verify the effectiveness of the proposed prediction method. Although they are utilized to accelerate the simulation scheme in this paper, the proposed numerical integrators are in fact general-purpose and can be applied to other areas.
6.4 A 1-to-3GHz Co-Channel Blocker Resistant, Spatially and Spectrally Passive MIMO Receiver in 65nm CMOS with +6dBm In-Band/In-Notch B 1dB

MIMO techniques exploit multipath signals from all directions. Unfortunately, this means that all the antennas can be jammed by a single co-channel blocker from any direction. Linear filtering techniques, that have an inverse, can be used to provide RF beamforming when combined with a baseband inverse without losing any of the multipath information. An example of such a filter includes the FFT/IFFT combination, shown in Fig. 6.4.1. Prior techniques have attempted to solve the MIMO co-channel blocker problem by providing nulls in individual directions [1]. These techniques provide finite jammer rejection in only one spatial direction. These have been extended to handle multiple spatial blockers [2]–[4]. However, all these techniques use active circuits for spatial filtering, which limits the ability to handle co-channel interference.
Intimate Partner Violence Experienced by Adults With Diagnosed HIV in the U.S.

Introduction Intimate partner violence is associated with adverse health consequences among people with diagnosed HIV, which could have implications for disease progression and transmission. However, nationally representative estimates of intimate partner violence among people with diagnosed HIV are lacking. Investigators used nationally representative data to estimate the prevalence of physical violence by an intimate partner among adults with diagnosed HIV and examine the differences by selected characteristics. Methods This analysis included interview and medical record data from the 2015−2017 cycles of the Medical Monitoring Project, analyzed in 2019. Weighted percentages and 95% CIs were used to report the prevalence of intimate partner violence among people with diagnosed HIV (N=11,768). Bivariate and multivariate differences in intimate partner violence by sociodemographic, behavioral, and clinical characteristics were examined using Rao–Scott chi-square tests (p Results Among people with diagnosed HIV, 26.3% reported having ever experienced intimate partner violence, and 4.4% reported having experienced intimate partner violence in the past 12 months. The prevalence of intimate partner violence differed by gender and gender/sexual identity. People who experienced intimate partner violence in the past 12 months were more likely to engage in behaviors associated with elevated HIV transmission risk and have unmet needs for supportive services. People who recently experienced intimate partner violence were less likely to be engaged in routine HIV care but were more likely to seek emergency care services and have poor HIV clinical outcomes. Conclusions This study's findings support the need for screening people with diagnosed HIV for intimate partner violence and offering linkage to supportive services. Screening for intimate partner violence among people with diagnosed HIV, coupled with supportive services and counseling, may lead to improved safety and HIV clinical outcomes and decreased need for emergency and inpatient medical services.
Using Reticulocyte Hemoglobin Equivalent as a Marker for Iron Deficiency and Responsiveness to Iron Therapy.

Abstract Objective To assess the accuracy of a simplified approach for the diagnosis of iron deficiency anemia (IDA) based on the complete blood cell count (CBC) and reticulocyte analysis. Patients and Methods Five hundred fifty-six consecutive, nonselected patients referred for diagnosis and/or treatment of anemia were included in this diagnostic study to compare the performance of reticulocyte hemoglobin equivalent (RET-He) versus traditional biochemical markers for diagnosis and treatment of IDA. Complete blood count, serum ferritin, iron, and transferrin saturation were performed as clinically indicated. Reticulocyte hemoglobin equivalent was measured with a Sysmex XN-450 analyzer on the residual CBC sample. The study period was from September 20, 2017, through and including November 15, 2018. Results Patients (N=556) were studied at baseline, of whom 150 were subsequently treated with intravenous iron. Receiver operating characteristic analysis yielded an RET-He cut-off of 30.7 pg to identify IDA (area under curve, 0.733; 95% CI, 0.692 to 0.775), with 68.2% sensitivity and 69.7% specificity. Patients (n=240) were seen at follow-up, with 57 treated and 183 not treated with intravenous iron. Responsiveness was defined as a hemoglobin increase of ≥1.0 g: a combination of RET-He Conclusion Data from CBC and RET-He can identify patients with IDA, determine need for and responsiveness to intravenous iron, and reduce time for therapeutic decisions. Limitations of this study are uncontrolled design, its single-site and retrospective nature, and that it requires prospective validation.
'Bacurau': ficção 'weird' e estética aceleracionista de expurgo colonial | 'Bacurau': weird fiction and accelerationist aesthetics of colonial purge

Resumo Neste artigo, sao analisados filme e roteiro de Bacurau (2019), dirigido por Kleber Mendonca Filho e Juliano Dornelles. Compreende-se a obra sob a perspectiva da ficcao weird pela conjuncao entre os elementos de futuridade da narrativa e os conflitos sociais do interior do Brasil, circunscritos a uma realidade historica. Misturando generos cinematograficos em um filme que vai do cangaco ao gore , Bacurau nos coloca frente a uma distopia sobre a proliferacao de tecnologias de vigilância e controle e, sobretudo, sobre a proliferacao de sistemas politicos de morte. Palavras-chave: Bacurau. Ficcao weird . Aceleracionismo. Desterritorialidade. Necropolitica. Estudos decoloniais. Abstract In this article I analyze the film and the script of Bacurau (2019), directed by Kleber Mendonca Filho and Juliano Dornelles. The work is understood from the perspective of weird fiction for the conjunction between the elements of futurity of the narrative and the social conflicts of Brazil’s countryside, anchored in a historical reality. Mixing cinematographic genres in a film that goes from Cangaco Cinema to Gore, Bacurau confronts us with a dystopia about the proliferation of surveillance and control technologies and, specially, about the proliferation of political systems of death. Keywords: Bacurau. Weird Fiction. Accelerationism. Deterritorialization. Necropolitics. Decolonial Studies.
Opioid Education and Prescribing Practices.

Background: Lack of training among health care providers (HCPs) to safely prescribe opioids is a contributing factor to the opioid crisis. Training and other resources have been developed to educate providers about safe and appropriate opioid prescribing practices. Method: The national survey was conducted with 2000 HCPs representing primary care physicians (PCPs), including family practice, general practice, and internal medicine; specialists (SPs); physician assistants (PAs); and nurse practitioners (NPs), a mix of primary care and specialists. This survey examined exposure to opioid educational information and opioid prescribing. Results: PCPs reported prescribing opioids for chronic pain to significantly more patients compared with other HCP groups. PCPs (89.8%) and NPs (85.5%) reported significantly greater exposure to opioid educational information compared with both SPs (71.9%) and PAs (78.8%). Overall, HCPs had limited knowledge about abuse-deterrent formulations, but PCPs had greater knowledge than other groups. HCPs had an increased likelihood of prescribing opioids to fewer patients in the last 3 months relative to the prior 12 months if they worked in a state or county clinic vs a solo or group practice type (adjusted odds ratio [AOR] = 1.97; 95% confidence interval [CI], 1.12–3.49) and were exposed to more opioid educational information during the last 12 months (AOR = 1.19; 95% CI, 1.06–1.32). Discussion: HCPs9 exposure to opioid educational information was associated with less opioid prescribing for chronic pain. Findings indicated a difference in exposure and knowledge gaps across provider groups. More information is needed on the content of opioid educational information provided to HCPs.
Sign, Sign, Everywhere a Sign: What Does “Reference” Mean to Academic Library Users?

Abstract In the library profession there is abundant use of jargon and acronyms to describe library activities. The terminology used is important to both market and describe library services. Often library professionals make assumptions that their users understand what library terminology means. Reference is a term widely understood by librarians and library workers, but is that understanding conveyed to the library user especially in academic institutions? The Regis University Library Reference Services Department faculty were curious to discover whether their students and faculty knew what the word “reference” meant especially since this word was on the sign above their service desk and used in the name of their department. A survey was developed by the Reference Services Department to answer that question and others. Results from the survey were used to propose a new name for the desk, department and librarians.
The Relationship between Interest in Teaching as a Career Choice and Perceptions of School/Classroom Environment of 7th and 8th Grade Students.

This study was conducted to ascertain whether future teachers, particularly students of color, can be identified at the 7th and 8th grade levels, and to determine whether their interest or noninterest in teaching is related to how they feel and think about school. Participants were 7th and 8th grade students (N-646) from eight California schools. To measure students' potential interest in teaching, a survey instrument was developed; to determine perceptions of school/classroom environment, the sample was asked to complete a true-false and forced .choice instrument, the "Quality of School Life." Findings indicated that it was possible to identify 7th and 8th grade students who were interested in teaching. Additional findings showed: that male students and students with negative perceptions of the school/classroom environment were less inclined to express inteLest in teaching; that students who felt part of the school were more apt to consider teaching as a career choice; that Asian students had a more positive perception of the school/classroom environment than African-American and Hispanic groups; and that European-Americans were no more likely to consider teaching as a career choice than any other cultural group."Information on demographic characteristics of respondents and results of statistical analyses are provided in tabular form. (Contains 15 references.)
Licensure as a Dilemma for Social Work Education: Findings of a National Study.

Abstract This paper reports on the first national survey to study the perceptions of MSW social work faculty of the relationship between licensing examinations and social work education. A non-random sample of 242 faculty from 39 systematically selected accredited schools from all states with licensure responded. The questionnaire focused on the impact of the national licensure examination on teaching, curriculum, and students. Among the major findings was that students are perceived as regarding the licensure exam as important to the profession and significant to their future. Faculty, however, only take the examination into consideration in the advisement process. Generally, they are unfamiliar with the examination's content, and they disregard it in curriculum development and in teaching.
Electric-field-induced index-matched harmonic generation in fibers

We would like to point out the possibility of the core of long fibers by proper fabrication of the fiber. One possible geometry, previously used for a fiber-optic sensor,1 is shown in Fig. 1. This geometry minimizes the problems of surface currents so that field strengths > 107 V/m can be generated.2 One could use such fibers to make a number of electric field controlled devices. We will discuss second harmonic generation.
Collecting a Motion-Capture Corpus of American Sign Language for Data-Driven Generation Research

American Sign Language (ASL) generation software can improve the accessibility of information and services for deaf individuals with low English literacy. The understand-ability of current ASL systems is limited; they have been constructed without the benefit of annotated ASL corpora that encode detailed human movement. We discuss how linguistic challenges in ASL generation can be addressed in a data-driven manner, and we describe our current work on collecting a motion-capture corpus. To evaluate the quality of our motion-capture configuration, calibration, and recording protocol, we conducted an evaluation study with native ASL signers.
ELECTRON MICROSCOPY OF A CONTRACTILE-VACUOLE MUTANT OF CHLAMYDOMONAS MOEWUSII (CHLOROPHYTA) DEFECTIVE IN THE LATE STAGES OF DIASTOLE1

Electron microscopy of a “vacuole-less” mutant of Chlamydomonas moewusii Gerloff revealed the presence of small anterior vacuoles. These vacuoles behaved like contractile vacuoles in wild-type cells, but they were apparently unable to complete diastole and discharge their contents. When wild-type and mutant cells were incubated in hypertonic medium, small coated vacuoles persisted in the region where contractile vacuoles form. When these cells were transferred to hypotonic medium, the vacuoles appeared to fill and fuse to form larger vacuoles Shortly after the appearance of full expanded contractile vacuoles, collapsed vacuoles were observed in wild-type cells suggesting the completion of diastole and the onset of systole. In mutant cells, the initial steps of filling and fusion to form larger vacuoles apparent interactions of vacuoles with the plasma membrane were not observed. New contractile vacuoles accumulated around the nucleus. When fusion of the contractile vacuole with the plasma membrane was blocked by EGTA, a similar accumulation of large vacuoles occurred. Our observations suggest that the contractile-vacuole mutant of C. Moewusii produces vacuoles which can accumulate excess water as part of the mechanism of osmoregulation but which cannot complete diastole.
Isoprenoid Hydrocarbons in Recent Sediments: Presence of Pristane and Probable Absence of Phytane

Pristane (2,6,10,14-tetramethylpentadecane) has been isolated from two recent marine sediments. Unlike their ancient counterparts, these sediments contain no detectable phytane. These two facts suggest a biochemical origin for at least a fraction of the sedimentary pristane and a later, geochemical formation of phytane. Commercial reagent-grade solvents (pentane, isooctane, methanol) contain appreciable quantities of fossil pristane and probably phytane.
Non-volatile memory properties of metal/SrTiO3/SiO2/Si structures

Abstract Non-volatile MIOS-type semiconductor memory elements were fabricated on silicon using electron-beam-evaporated SrTiO 3 as the second insulator. The charge storage properties were characterized for Au/SrTiO 3 /SiO 2 /Si structures. Our results show that a short-time post-deposition oxygen annealing is essential to anneal out the radiation damage resulting from electron beam deposition. The devices on n-type silicon substrates show fast switching for a positive applied pulse and a much lower switching speed (longer than 20 ms) for a negative pulse, which is believed to be caused by the minority carrier restriction. The devices show a logarithmic decay of the flat-band voltage as a function of time, with a rate of 0.4 V decade -1 for stored electrons and 0.5 V decade -1 for stored holes. The devices can survive 10 4 write-erase cycles of endurance testing. An inversion of the surface silicon layer is found for devices on p-type substrates subjected to high temperature oxygen annealing.
Co-Learning With Home Care Aides and Their Clients: Collaboratively Increasing Individual and Organizational Capacities

Changes in health care provide unprecedented opportunities for collaboration across research, education, and practice for the common goal of enhancing the well-being of older adults and their caregivers. This article describes how a pilot project, Promoting Seniors’ Health with Home Care Aides, has synergistic education, research, and practice effects that enhance individual and organizational capacities. This pilot is an innovative partnership with home care aides to deliver a safe physical activity program appropriate for frail seniors in a real-life public home care program. The intervention and research occur in older adults’ homes and thus provide rare opportunities for the research team and partners to learn from each other about dynamics of home care in older adults’ life contexts. Co-learning is essential for continuous quality improvement in education, research and practice. The authors propose to establish “teaching home care” to ensure ongoing co-learning in gerontology and geriatrics.
IMAGING THE IMAGELESS: SYMBOL AND PERCEPTION IN EARLY CHINESE THOUGHT

The “revivification of philosophy through contact with the fundamental symbols of consciousness” which the Hermeneutician Paul Ricoeur so eloquently called for in his Symbolism of Evil has, I believe, particular relevance for the study of traditional Chinese thought.1 Beginning in the Warring States period, a number of Chinese thinkers began to appreciate evocative symbols as a more apt medium to reflect reality than descriptive language. Concluding, like the modern theologian Paul Tillich, that “symbolic language alone is able to express the ultimate,” they began to devise a conscious theory of symbolism which reached full articulation by the early Han era. By borrowing upon some modern critical ideas, I hope to show that this theory of symbolism discloses aspects of early Chinese thinking about perception and reality that are not always fully delineated or appreciated in contemporary studies of Chinese thought.
Heterogeneous Sources of Target Patterns in Reaction−Diffusion Systems

We show that the rate of spontaneous formation of centers of target patterns in the Belousov−Zhabotinsky reaction−diffusion system depends strongly on the concentration of the initial reagents. Computer simulations show that the dependence can be explained by the hypothesis that small heterogeneous impurities are the sources of the target patterns.
Photoreduction of manganese oxides in seawater and its geochemical and biological implications

Manganese is an essential micronutrient for all organisms. Its requirement by plants is particularly high because of its role in the oxidation of water in photosynthesis1–5. According to thermodynamic considerations, manganese should exist in oxic waters as MnO2 (ref. 6) which is insoluble and, therefore, not directly available for plant nutrition. In contrast to thermody-namic predictions, however, most of the manganese in near surface seawater exists as soluble reduced Mn(II) (ref. 7). Although slow oxidation kinetics are at least partially responsible for the presence of Mn(II) in oxic waters8,9, reduced manganese, nevertheless, should be converted to particulate manganese oxides (at rates that depend on several kinetic factors10,11) and be lost from the water column by sinking12. We report here experiments that demonstrate photoreduction of manganese oxides by dissolved organic substances (humic substances) in seawater. Such reactions appear to be important in maintaining manganese in a dissolved reduced form in photic waters, thereby enhancing its supply to phytoplankton.
Correlation between CYP1A1 transcript, protein level, enzyme activity and DNA adduct formation in normal human mammary epithelial cell strains exposed to benzo[a]pyrene.

The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (BP) is thought to bind covalently to DNA, through metabolism by cytochrome P450 1A1 (CYP1A1) and CYP1B1, and other enzymes, to form r7, t8, t9-trihydroxy-c-10-(N 2-deoxyguanosyl)-7,8,9,10-tetrahydro-benzo[a]-pyrene (BPdG). Evaluation of RNA expression data, to understand the contribution of different metabolic enzymes to BPdG formation, is typically presented as fold-change observed upon BP exposure, leaving the actual number of RNA transcripts unknown. Here, we have quantified RNA copies/ng cDNA (RNA cpn) for CYP1A1 and CYP1B1, as well as NAD(P)H:quinone oxidoreductase 1 (NQO1), which may reduce formation of BPdG adducts, using primary normal human mammary epithelial cell (NHMEC) strains, and the MCF-7 breast cancer cell line. In unexposed NHMECs, basal RNA cpn values were 58–836 for CYP1A1, 336–5587 for CYP1B1 and 5943–40112 for NQO1. In cells exposed to 4.0 µM BP for 12h, RNA cpn values were 251–13234 for CYP1A1, 4133–57078 for CYP1B1 and 4456–55887 for NQO1. There were 3.5 (mean, range 0.2–15.8) BPdG adducts/108 nucleotides in the NHMECs (n = 16), and 790 in the MCF-7s. In the NHMECs, BP-induced CYP1A1 RNA cpn was highly associated with BPdG (P = 0.002), but CYP1B1 and NQO1 were not. Western blots of four NHMEC strains, chosen for different levels of BPdG adducts, showed a linear correlation between BPdG and CYP1A1, but not CYP1B1 or NQO1. Ethoxyresorufin-O-deethylase (EROD) activity, which measures CYP1A1 and CYP1B1 together, correlated with BPdG, but NQO1 activity did not. Despite more numerous levels of CYP1B1 and NQO1 RNA cpn in unexposed and BP-exposed NHMECs and MCF-7cells, BPdG formation was only correlated with induction of CYP1A1 RNA cpn. The higher level of BPdG in MCF-7 cells, compared to NHMECs, may have been due to a much increased induction of CYP1A1 and EROD. Overall, BPdG correlation was observed with CYP1A1 protein and CYP1A1/1B1 enzyme activity, but not with CYP1B1 or NQO1 protein, or NQO1 enzyme activity.
S1-S0 INTERNAL CONVERSION IN KETENE. 1. THE ROLE OF CONICAL INTERSECTIONS

The role of conical intersections in the internal conversion (S1 → S0) of photoexcited ketene (H2CCO) is analyzed. The energy-minimized projection of a portion of the S1(1A‘ ‘)−S0(1A‘) seam of the conical intersection near the minimum energy-crossing point is studied as a function of the key internal coordinates R(C−C) and ∠CCO. The characteristic parameters of the conical intersection points are used, to identify the two modes that evince the conical nature of the intersection, to determine the energy and singular part of the derivative coupling near the conical intersection, and to construct a transformation to diabatic states that rigorously removes the singularity in the derivative coupling. From the Franck−Condon region of the S0 → S1 excitation, barrierless paths were identified on S1 leading to Re(A1A‘ ‘), the equilibrium geometry of S1 ketene, and to Rmex, the minimum energy point on the S1−S0 seam of conical intersection. Following internal conversion onto S0 near Rmex, the barrierless paths lead...
Heat capacity of superconducting ternary molybdenum sulfides.

The heat capacities of AgMo 4 S 5 , PbMo 6 S 7 , and SnMo 5 S 6 are reported. These ternary molybdenum sulfides have been found to be bulk superconductors with very large values of electronic heat capacity coefficients and very low values of Debye temperatures.
A dimeric molecular precursor [(tBuO)2Ti{μ-O2Si[OSi(OtBu)3]2}]2 to Ti(IV)/SiO2 catalysts for selective cyclohexene epoxidation

The new dimeric complex [(tBuO)2Ti({mu}-O2Si[OSi(OtBu)3]2)]2 (1), prepared via silanolysis of Ti(OtBu)4 with (HO)2Si[OSi(OtBu)3]2, is a structural and spectroscopic (NMR, FT-IR, UV-vis, XPS) model for Ti(IV)/SiO2. The molecular complex was used to prepare titanium-containing silica materials through both the thermolytic molecular precursor method (yielding TiO2{center_dot}3SiO2) or by grafting 1 onto mesoporous SBA-15 silica. Grafting 1 onto SBA-15 yields mostly isolated Ti(IV) sites, as evidenced by DRUV-vis and photoluminescence spectroscopies. The resulting materials were found to be active and highly selective in the epoxidation of cyclohexene, yielding up to 71% of cyclohexene oxide based on oxidant (cumene hydroperoxide) after 2 h at 65 C in toluene.
Transgenic rice and rice genome research

Abstract The recent rapid progress in transferring foreign genes for expression in rice is evaluated. There is an apparent need for an international database and for information exchange about transgenic rice plants between molecular biologists, plant breeders, company researchers and government regulators. Progress in rice genome mapping will enhance further the development, evaluation and monitoring of transgenic rice plants. The special conditions of rice-growing nations and transport of released genes over international borders need attention when developing and deploying new transgenic rice varieties in Asia and elsewhere.
Vitamin E: Critical Review of Its Current Use in Cosmetic and Clinical Dermatology

Background and Objective. The lipophilic antioxidant vitamin E has been used for more than 50 years in clinical and experimental dermatology. However, although a large number of case reports were published, there is still a lack of controlled clinical studies providing a rationale for clinical indications and dosage. In contrast, advances in basic research on the physiology, mechanism of action, penetration, bioconversion, and photoprotection of vitamin E in human skin have led to the development of numerous new formulations for use in cosmetics and skin care products. Results. This article reviews the basic mechanisms and possible cosmetical and clinical implications of the recent advances in cutaneous vitamin E research. Experimental evidence suggests that topical and oral vitamin E has anticarcinogenic, photoprotective, and skin barrier–stabilizing properties. Conclusion. Although its current use is largely limited to cosmetics, controlled clinical studies for indications such as atopic dermatitis or prevention of photocarcinogenesis are needed to evaluate the clinical benefit of vitamin E. JENS J. THIELE, MD, SHERRY N. HSIEH, PHD, AND SWARNA EKANAYAKE-MUDIYANSELAGE, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.
Dopaminergic modulation of tracer coupling in a ganglion-amacrine cell network.

Many retinal ganglion cells are coupled via gap junctions with neighboring amacrine cells and ganglion cells. We investigated the extent and dynamics of coupling in one such network, the OFF α ganglion cell of rabbit retina and its associated amacrine cells. We also observed the relative spread of Neurobiotin injected into a ganglion cell in the presence of modulators of gap junctional permeability. We found that gap junctions between amacrine cells were closed via stimulation of a D1 dopamine receptor, while the gap junctions between ganglion cells were closed via stimulation of a D2 dopamine receptor. The pairs of hemichannels making up the heterologous gap junctions between the ganglion and amacrine cells were modulated independently, so that elevations of cAMP in the ganglion cell open the ganglion cell hemichannels, while elevations of cAMP in the amacrine cell close its hemichannels. We also measured endogenous dopamine release from an eyecup preparation and found a basal release from the dark-adapted retina of approximately 2 pmol/min during the day. Maximal stimulation with light increased the rate of dopamine release from rabbit retina by 66%. The results suggest that coupling between members of the OFF α ganglion cell/amacrine cell network is differentially modulated with changing levels of dopamine.
A progress report on a U.S. National Survey of Geospatial Framework Data

Abstract Although federally supported geospatial data clearinghouses have appeared on the Internet, there exist few resources allowing for a coordinated collection of publicly available geospatial data over large areas. The completion of a national survey of potential producers of geospatial data provides users with a new way of learning about relevant, publicly accessible data when they embark on projects with a spatial component. This article presents a progress report on the National Survey of Geospatial Framework Data. The survey's methodology is described, allowing for readers to anticipate both the nature and extent of the survey results. Also described are the means by which the final results will be released. The survey results will serve as a major national source of information regarding where public geospatial data can be obtained at all levels of government. This article is intended to encourage access to the survey results so the results reach an appropriate audience while still timely and relevant. The survey will serve as a new source of information having implications for access to geospatial data nationwide. Published by Elsevier Science Ltd
The effect of forebrain lesions in the neonatal rat: Survival of midbrain dopaminergic neurons and the crossed nigrostriatal projection

Lesions were placed in the striatum and the olfactory tubercle of 1-day-old rat pups. Control and experimental animals were raised to adulthood. Efferent projections of mesencephalic neurons were examined by injecting the retrograde tracers horseradish peroxidase or Fast Blue into the undamaged striata of some experimental animals. The survival of the mesencephalic dopaminergic neurons was monitored by using immunocytochemical localization of tyrosine hydroxylase. Small lesions in the caudate-putamen had no appreciable effect on the survival of tyrosine hydroxylase-containing neurons in the mesencephalon, but the density of dopaminergic terminals adjacent to the lesion increased in the remaining caudate-putamen. Striatal lesions that involved an estimated area of more than one-third resulted in loss of dopamine neurons of the substantia nigra compacta. Rostral lesions in the striatum affected mostly rostrally positioned neurons in the substantia nigra. Dorsal lesions of the caudate-putamen resulted in disappearance of dorsal A9 neurons. Reduction of the A10 and A8 dopamine neuron groups occurred if the neonatal lesions involved the olfactory tubercle and nucleus accumbens. Some tyrosine hydroxylase-containing neurons persisted even after the largest lesions. These dopaminergic neurons formed a crossed nigrostriatal pathway which was confirmed by retrogradely transported tracers. The density of this crossed projection in the adult appeared unaffected by the neonatal lesion. We concluded that dopaminergic neurons form topographically ordered projections with their targets in the newborn rat. Rearrangement of these fibers appeared limited, but compensatory increase of axon terminal density was evident in partially lesioned target areas.
Does the economy affect teenage substance use

This research examines how teenage drug and alcohol use responds to changes in the economy. In contrast to the recent literature confirming pro-cyclical alcohol use among adults, this research offers strong evidence that a weaker economy leads to greater teenage marijuana and hard-drug use and some evidence that a weaker economy also leads to higher teenage alcohol use. The findings are based on logistic models with state and year fixed effects, using teenagers from the NLSY-1997. The evidence also indicates that teenagers are more likely to sell drugs in weaker economies. This suggests one mechanism for counter-cyclical drug use - that access to illicit drugs is easier when the economy is weaker. These results also suggest that the strengthening economy in the 1990s mitigated what would otherwise have been much larger increases in teenage drug use.
A Comparative Study of Recidivists and Contraceptors Along the Dimensions of Locus of Control and Impulsivity

Abstract The research examined personality differences between repeat aborters, initial aborters, and nulliparas. A review of the literature in the area has documented the demographic characteristics of women who continually seek repeated abortion. This study was an attempt to differentiate between women who contracept from those who seek abortion repeatedly on the basis of personality differences. The findings indicate that repeaters who seek abortion at the time of personality testing perceive themselves low in impulsivity, a finding similar to that for women who. have never been pregnant and are seeking contraceptive services. Results are examined from the perspective of inaccurate vs accurate self-perceptions. No differences were found with respect to locus of control.
Mapping Human History: Discovering the Past through Our Genes

As human genetics becomes increasingly a part of everyday experience, there is a need for literature that accurately explains our science to the general public. Steve Olson, an experienced science writer, has done an excellent job of balancing scientific content with journalistic spice in this new book about the genetic history of our species.
Infrainguinal bypass is associated with lower perioperative mortality than major amputation in high-risk surgical candidates

Background Major amputation is often selected over infrainguinal bypass in patients with severe systemic comorbidities because it is assumed to have lower perioperative risks, yet this assumption is unproven and largely unexamined. Methods The 2005 to 2008 National Surgical Quality Improvement Project (NSQIP) database was used to identify all patients undergoing either infrainguinal bypass or major amputation using procedural codes. Patients with systemic or local infections were excluded. A subset of high-risk patients were then defined as American Society of Anesthesiologists (ASA) class 4 or 5, or ASA class 3 with renal failure, dyspnea at rest, ventilator dependence, recent congestive heart failure, or recent myocardial infarct. Propensity score matching was used to obtain two high-risk patient groups matched for preoperative characteristics. Results No significant differences in demographic, preoperative, or anesthetic variables were found between the matched, high-risk amputation or bypass groups (792 and 780 patients, respectively). Bypass was associated with a lower 30-day postoperative mortality than amputation (6.54% vs 9.97%; P = .0147). Amputation was associated with higher rates of pulmonary embolism (0.9% vs 0% for amputation vs bypass groups, respectively; P = .009) and urinary tract infection (5.2% vs 2.7%; P = .01), while bypass was associated with higher rates of return to the operating room (14.1% vs 27.6%; P P = .054). The postoperative time to discharge did not differ between the two groups. Conclusion The decision to perform an infrainguinal bypass or amputation should depend on well-established predictors of graft patency and functional success rather than presumptions about different perioperative risks between the two procedures.
Solution behavior of linear-dendritic rod diblock copolymers in methanol.

The solution behavior of spherical dendrimers as well as hybrid-linear dendritic diblock copolymers has been extensively studied, and the size, shape, and ability of these polymers to encapsulate small molecules have led to their comparison with traditional micelles. We have recently reported the synthesis of a new dendritic copolymer architecture, the linear-dendritic rod diblock copolymer, and in this work, we examine the solution behavior of these unique polymers in methanol at 25 °C, using dynamic light scattering and intrinsic viscosity measurements. The diblock copolymers consist of a linear poly(ethylene oxide)−poly(ethylene imine) diblock copolymer backbone around which poly(amido amine) branches have been divergently synthesized from the poly(ethylene imine) block. The hydrodynamic radii and the viscometric radii of the polymers were found to increase slowly with increasing generation up to generation 3.5; however, after generation 3.5, the radii were found to increase very rapidly. This increase...