cssi/SciSciGPT-SciSciNet huggingface dataset:
Classroom Quality and Adolescent Student Engagement and Performance in Mathematics: A Multi-Method and Multi-Informant Approach.

Mathematics learning, engagement, and performance are facilitated by quality interactions within the classroom environment. Researchers studying high-quality interactions in mathematics classrooms must consider adopting multiple methods of data collection so as to capture classroom quality from all perspectives. As such, this longitudinal study examined student, teacher, and observer perspectives of interaction quality in mathematics classrooms and their predictive associations with mathematics outcomes. Data were collected during the fall and spring semesters of the 2015–2016 school year from 1501 students in 150 mathematics classes (n = 499 fifth graders, 523 seventh graders, 479 ninth graders; 51% female; 51% European American, 30% African American, and 19% other ethnic background; 52% qualifying for free/reduced price lunch). Observer and aggregated student reports of interaction quality at the classroom level were moderately correlated with one another, and these reports predicted student mathematics engagement and performance. Individual student reports of interaction quality also predicted math engagement and performance; yet, teacher reports of interaction quality did not align with student or observer perspectives. Furthermore, teacher reports did not predict student mathematics outcomes. Implications for research, practice, and policy are discussed.
IDIOPATHIC LATE LEFT VENTRICULAR LEAD DISLODGEMENT LEADING TO PULMONARY EMBOLISM

Biventricular pacing uses passive fixation to position a left ventricular lead (LVL) in the coronary sinus (CS). Early LVL dislodgement (< 1 month) is common but idiopathic late LVL dislodgement causing pulmonary embolism (PE) is rare and potentially fatal. A 55 year old male with non-ischemic
Linezolid and fentanyl: An underrecognized drug-to-drug interaction

What is known and objective Despite its frequent use in clinical practice, fentanyl's pro-serotonergic effects are underrecognized, especially in combination with linezolid. Life-threatening reactions can occur. Case summary We report a case of serotonin syndrome developed shortly after the initiation of linezolid in a 63-year-old patient in whom selective serotonin reuptake inhibitor therapy was discontinued for the duration of antibiotic therapy. However, fentanyl transdermal patch treatment was inadvertently continued. Noteworthy, 24 hours following discontinuation of linezolid, the patient experienced complete resolution of symptoms. What is new and conclusion Fentanyl can increase the intrasynaptic release of serotonin through their effects on y-amino butyric acid and its phenylpiperidine chemical structure. We illustrate the importance of thorough medication reconciliation and review of all potential drug-to-drug interactions when indicating linezolid therapy to ensure patient safety. We believe that our case provides novel observations and insight that could help recognize similar cases in clinical practice.
Implementation of a Teaching Electronic Medical Record within Didactic Instruction Using a Drug Information Question Assignment.

Background: Pharmacy graduates are expected to be practice-ready to deliver quality patient care, which includes having comprehensive knowledge of health informatics and electronic medical records (EMRs). The purpose of this study was to (1) incorporate an EMR within a pharmacy student assignment, and (2) assess student perceptions of use of the EMR. Methods: Student pharmacists received a patient-specific drug-related question and were required to use an EMR to provide an accurate response. Following completion of the assignment, students were invited to complete a retrospective, pre-post survey instrument to collect their perceptions. Results: Only 28.8% of respondents reported prior experience using an EMR. Student perceptions about use of an EMR within the didactic setting significantly improved from before to after the assignment. Differences were found in respondents who agreed that didactic use of an EMR increased their confidence in obtaining information from an EMR (20.5% to 82.8%) and improved their knowledge of EMR systems (61.4% to 89.3%). Conclusions: Implementation of an EMR within didactic instruction may serve as the first exposure to health informatics for students and positively impacts student perceptions of these tools prior to entry into pharmacy practice.
Biofouling Characteristics of Graphene Oxide Membrane in a Protein-rich Environment

Membrane biofouling has inhibited permselective separation processes for decades, requiring frequent membrane backwash treatment or replacement to maintain efficacy. However, frequent treatment is not viable for devices with a continuous blood flow such as a wearable or implantable dialyzer. In this study, the biofouling characteristics of a highly hemocompatible graphene oxide (GO) membrane developed through a novel self-assembly process is studied in a protein-rich environment and compared with performance of a state-of-the-art commercial polymer membrane dialyzer. The studies are conducted in phosphate-buffered saline (PBS) environment using human serum albumin (HSA), which represents 60% of the blood protein, at the nominal blood protein concentration of 1 g L-1. Protein aggregation on the membrane surface is evaluated by monitoring the change in the membrane flux and SEM imaging. The GO membrane water flux declined only ~10% over a week-long test whereas the polymer membrane flux declined by 50% during the same period. The SEM images show that HSA primarily aggerates over the graphitic regions of nanoplatelets, away from the charged hydrophilic edges. This phenomenon leaves the open areas of the membrane formed between the nanoplatelets edges, through which the species pass, relatively intact. In contrast, HSA completely plugs the polymer membrane pores resulting in a steady decline in membrane permeability.
Representation of women in vascular surgery science and societies.

Abstract Objective Medical schools and surgical residencies have seen an increase in the proportion of female matriculants, with 30% of current vascular surgery trainees being women over the past decade. There is widespread focus on increasing diversity in medicine and surgery in an effort to provide optimal quality of patient care and the advancement of science. The presence of gender diversity and opportunities to identify with women in leadership positions positively correlates with women choosing to enter traditionally male-dominated fields. The purpose of this study was to evaluate the representation of women in regional and national vascular surgical societies over the last 20 years. Methods A retrospective review of the meeting programs of vascular surgery societies was performed. Data were collected on abstract presenters, moderators, committee members and chairs, and officers (president, president-elect, vice president, secretary, and treasurer). The data were divided into early (1999-2009) and late (2010-2019) time periods. Results Five regional and five national societies' data were analyzed, including 139 meetings. The mean percentage of female abstract presenters increased significantly from 10.9% in the early period to 20.6% in the late period (P Conclusions Over the past two decades, there has been a significant increase in the representation of women in vascular surgery societies among those presenting scientific work, serving as meeting moderators, and serving as committee members. However, the representation of women among committee chairs, senior authors, and society leadership has not kept up pace with the increase noted at other levels. Efforts to recruit women into the field of vascular surgery as well as to support the professional development of female vascular surgeons are facilitated by the presence of women in leadership roles. Increasing the representation of women in vascular society leadership positions may be a key strategy in promoting gender diversity in the vascular surgery field.
‘Just-in-Time’ Parenting: A Two-Month Examination of the Bi-directional Influences Between Parental Mediation and Adolescent Online Risk Exposure

Parental mediation is a key factor that influences adolescents’ exposure to online risk. Yet, research on this topic has mostly been cross-sectional and correlative, not exploring whether the relationship between parental mediation and adolescent online risk exposure could be bi-directional, where teens’ risk exposure influences parenting practices. To address this gap, we conducted an eight week, repeated measures web-based diary study with 68 adolescents (aged 13–17) and their parents to examine the relationships between three parental mediation strategies (active mediation, monitoring, and restriction) and three adolescent online risk types (explicit content, sexual solicitations, and online harassment) teens reported encountering online. Overall, parents and teens had significantly different perceptions regarding parental mediation, which yielded some consistent and conflicting results. Parents and teens agreed that parental restriction significantly increased the week in which the teen encountered all three risk types, and active mediation increased during the week in which the teen encountered online harassment. Parents and teens also consistently reported that restriction significantly decreased the week after an online harassment incident. Overall, we found that parental mediation and teen online risk exposure were most often significantly correlated in the same week, suggesting parenting occurred ‘just-in-time,’ rather than parents and teens’ behaviors bi-directionally influencing one another significantly from week-to-week. Our findings provide new insights into parent-teen perspectives on parental mediation and highlight the bi-directional relationship of parental mediation and online risk. We offer recommendations to facilitate ‘just in time’ parenting and provide teens with the necessary support to help keep them safe online.
Software-Defined Workflows for Distributed Interoperable Closed-Loop Neuromodulation Control Systems

Closed-loop neuromodulation control systems facilitate regulating abnormal physiological processes by recording neurophysiological activities and modifying those activities through feedback loops. Designing such systems requires interoperable service composition, consisting of cycles. Workflow frameworks enable standard modular architectures, offering reproducible automated pipelines. However, those frameworks limit their support to executions represented by directed acyclic graphs (DAGs). DAGs need a pre-defined start and end execution step with no cycles, thus preventing the researchers from using the standard workflow languages as-is for closed-loop workflows and pipelines. In this paper, we present NEXUS , a workflow orchestration framework for distributed analytics systems. NEXUS proposes a Software-Defined Workflows approach, inspired by Software-Defined Networking (SDN), which separates the data flows across the service instances from the control flows. NEXUS enables creating interoperable workflows with closed loops by defining the workflows in a logically centralized approach, from microservices representing each execution step. The centralized NEXUS orchestrator facilitates dynamically composing and managing scientific workflows from the services and existing workflows, with minimal restrictions. NEXUS represents complex workflows as directed hypergraphs (DHGs) rather than DAGs. We illustrate a seamless execution of neuromodulation control systems by supporting loops in a workflow as the use case of NEXUS . Our evaluations highlight the feasibility, flexibility, performance, and scalability of NEXUS in modeling and executing closed-loop workflows.
Examining the Dynamics Between Formal and Informal Institutions in Progressive City Planning

What explains the institutionalization of progressive city planning practices? Using Medellin as a case study, I analyze how state and nonstate actors target both formal and informal institutions i...
Transcriptomic analysis of loss of Gli1 in neural stem cells responding to demyelination in the mouse brain

In the adult mammalian brain, Gli1 expressing neural stem cells reside in the subventricular zone and their progeny are recruited to sites of demyelination in the white matter where they generate new oligodendrocytes, the myelin forming cells. Remarkably, genetic loss or pharmacologic inhibition of Gli1 enhances the efficacy of remyelination by these neural stem cells. To understand the molecular mechanisms involved, we performed a transcriptomic analysis of this Gli1-pool of neural stem cells. We compared murine NSCs with either intact or deficient Gli1 expression from adult mice on a control diet or on a cuprizone diet which induces widespread demyelination. These data will be a valuable resource for identifying therapeutic targets for enhancing remyelination in demyelinating diseases like multiple sclerosis.
Data Partitioning and Unbalanced Error Protection for H.263 Video Transmission over Wireless Channels

Recently, the growing demand and potential market for new services and applications has spurred the research on video transmission and multimedia services over wireless networks. In terms of channel characteristics, the radio channels in wireless networks are error prone and their bandwidth is limited due to the availability of accessible frequency spectrum. The video bit stream, after efficient source coding, is very vulnerable to channel errors, it therefore presents a challenging design problem to obtain acceptable quality video over lossy radio channels. Classified (layered) source coding and unbalanced (unequal) error protection provide a possible mechanism to enable the reliable transmission of compressed video bit streams over wireless links.
The X-Ray Sources of M31

The well determined distance to M31 provides a unique opportunity to study galactic x-ray sources in a spiral system at a well known distance, without the uncertainty on the luminosity inherent to the study of x-ray sources in our own Galaxy. M31 was extensively mapped with both imaging instruments on board the Einstein satellite. Preliminary results were presented earlier (cf. Long and Van Speybroeck 1983, and references therein), and a list of possible identifications of sources outside the very confused region around the nucleus was given by Crampton et al. (1984). I am reporting the main results obtained so far from the ongoing careful analysis of the x-ray observations.
Facilitated diffusion of glucose

Article de synthese sur la diffusion facilite du glucose a travers les membranes cellulaires. Proteines de transport du glucose (identification et structure II re ), proprietes catalytiques de ces proteines (stereoselectivite, modele de transport dans l'erythrocyte humain et dans d'autres cellules mammiferes), regulation du transport facilite du glucose
Capital Accumulation and Macro Policy in South Africa: Political Instability, Distributive Conflict, and Economic Institutions, 2002

This paper explores the institutional factors behind the crisis of capital accumulation in South Africa in the 1970s and 1980s. Because of its focus on institutional stability, the paper contributes to the literature on the existence of an apartheid social structure of accumulation in which economic and political institutions are important determinants of investment. Investment function estimates show that political instability accounted for most of the fall in the rate of accumulation, independent of distributive outcomes, such as the level of profitability. Based on these findings, the paper argues that tensions between political stability, democratic reforms, and distributive outcomes prompted the adoption of market-oriented macroeconomic policies in the post-apartheid era that have so far failed to move the economy away from the low rates of accumulation characteristic of recent decades.
Acid-base characteristics of fetuses with intrauterine growth retardation during labor and delivery

The maternal and fetal cord blood from 37 infants with intrauterine growth retardation (IUGR) and 108 normal growth (AGA) infants were compared for lactate, pH, and blood gas values in an attempt to find whether there is any difference in stressed response in IUGR fetuses during labor and delivery. Both maternal and fetal blood lactate levels increased with progression of labor, fetal lactate being higher than the maternal lactate. Without intrapartum fetal heart rate decelerations, IUGR fetuses did not show a difference in umbilical arterial lactate, pH, and blood gases, compared to AGA fetuses. With intrapartum fetal heart rate decelerations, IUGR fetuses demonstrated a significantly higher lactate level than that of AGA fetuses. We conclude that IUGR fetuses tolerate labor less well than do AGA fetuses. In the presence of late decelerations, earlier intervention is preferable because of the increased likelihood of metabolic acidosis.
Interplanetary acceleration of coronal mass ejections

Using an observed relation between speeds of CMEs near the Sun and in the solar wind, we determine an “effective” acceleration acting on the CMEs. We found a linear relation between this effective acceleration and the initial speed of the CMEs. The acceleration is similar to that of the slow solar wind in magnitude. The average solar wind speed naturally divides CMEs into fast and slow ones. Based on the relation between the acceleration and initial speed, we derive an empirical model to predict the arrival of CMEs at 1 AU.
Stratified case sampling and the use of family controls

We compare the asymptotic relative efficiency (ARE) of different study designs for estimating gene and gene-environment interaction effects using matched case-control data. In the sampling schemes considered, cases are selected differentially based on their family history of disease. Controls are selected either from unrelated subjects or from among the case's unaffected siblings and cousins. Parameters are estimated using weighted conditional logistic regression, where the likelihood contributions for each subject are weighted by the fraction of cases sampled sharing the same family history. Results showed that compared to random sampling, over-sampling cases with a positive family history increased the efficiency for estimating the main effect of a gene for sib-control designs (103-254% ARE) and decreased efficiency for cousin-control and population-control designs (68-94% ARE and 67-84% ARE, respectively). Population controls and random sampling of cases were most efficient for a recessive gene or a dominant gene with an relative risk less than 9. For estimating gene-environment interactions, over-sampling positive-family-history cases again led to increased efficiency using sib controls (111-180% ARE) and decreased efficiency using population controls (68-87% ARE). Using case-cousin pairs, the results differed based on the genetic model and the size of the interaction effect; biased sampling was only slightly more efficient than random sampling for large interaction effects under a dominant gene model (relative risk ratio = 8, 106% ARE). Overall, the most efficient study design for studying gene-environment interaction was the case-sib-control design with over-sampling of positive-family-history-cases.
Electric-field-induced orientation of surfactant-templated nanoscopic silica.

While exhibiting a well-defined nanometer-level structure, surfactant-templated nanoscopic silicas produced via self-assembly do not always possess long-range order. We demonstrate that long-range ...
Case Report: Nocardia Pneumonitis and the Adult Respiratory Distress Syndrome

This report describes the progression of an acute regional Nocardia pneumonitis to diffuse pulmonary parenchymal disease in a previously healthy man. The pathophysiologic manifestations of disease evolved from that of a severe bacterial pneumonia to the adult respiratory distress syndrome. This progression may be representative of pyogenic bacterial pneumonias, which are associated with the syndrome even when the infections are adequately treated.
The effect of food on the in vivo behaviour of enteric coated starch capsules

Abstract Eight healthy volunteers were entered into a randomised, open crossover study to investigate the in vivo behaviour of an enteric coated starch capsule. A radiolabelled preparation was administered to each volunteer on two occasions separated by 7 days, once in the fasted state and once after a medium breakfast. The gastrointestinal transit and disintegration behaviour of the enteric coated capsule was followed using gamma scintigraphy. No loss of integrity was observed in the stomach confirming the gastroresistant properties of the preparation. With one exception, all capsules released their contents in the small bowel. Capsule disintegration was influenced by the gastric residence time; capsules which were retained within the fed stomach disintegrated sooner following gastric emptying, compared with capsules which left the stomach rapidly.
Indicators for quality improvability and bottleneck sequence in flexible manufacturing systems with batch production

In this paper we study product quality in flexible manufacturing systems with batch production using a Markov chain model. To improve the quality performance in such systems, the notions of quality improvability and bottleneck sequence are introduced. Indicators for identifying the quality improvability and bottleneck sequence, based on data measured on the factory floor rather than complicated calculations, are developed. A case study of improving quality at an automotive paint shop is introduced.
Self-concept in Lebanese and Arab-American pre-adolescents.

Summary The present study assessed self-concepts of 102 (35 boys, 67 girls) Arab-American pre-adolescents (M age = 11.9 yr., SD = .8) and compared scores with those of 105 (43 boys, 62 girls) Arab national students (M age = 12.3 yr., SD = .7) in Lebanon. The Arab-American students scored significantly higher than the group of Arab students in Lebanon on 6 of 8 subscales of Marsh's Self-description Questionnaire-I, suggesting overall higher self-concept on subscales for physical ability, physical appearance, peer relations, reading, general school, and general self-concept. The results are consistent with expectations associating biculturalism with high self-concept.
Medical service reform: Rituals, hypothetical games and the social sciences

The purpose of this article is two-fold. It provides a framework for understanding what happened in the recently failed effort to reform the U.S. medical industry. The guiding theme is that politicians, the public at large and social scientists framed the discussion in largely ritualistic terms: “bureaucratic reformers” advocated a federally regulated national health system: “market reformers” advocated a free market health system. This framing of the debate doomed meaningful reform, whether or not the Clinton plan had passed. Second, with this discussion as backdrop, a closely related problem is examined:1 why most social scientists failed to introduce more thoughtful, critical discussion into public debate. This part of the discussion draws on, though is not limited to, the author's experience of more than a decade with issues of health planning and policy,2 in medical industry reform in Omaha and in Nebraska.
Bacterial expression and purification of a heterodimeric adrenomedullin receptor extracellular domain complex using DsbC-assisted disulfide shuffling

Adrenomedullin (AM) is a peptide hormone that is a potent vasodilator and is essential for vascular development. The AM receptor is a heterodimeric cell surface receptor composed of the calcitonin receptor-like receptor (CLR), a class B G protein-coupled receptor, in association with either of two receptor activity modifying protein (RAMP) coreceptors, RAMP2 or -3. The extracellular domains (ECDs) of CLR and the RAMPs form the primary AM binding site. Here, we present novel methodology for expression and purification of a heterodimeric AM receptor ECD complex as an MBP-CLR ECD fusion protein in association with the RAMP2 ECD. Co-expression of the RAMP2 ECD with the disulfide bond isomerase DsbC in the oxidizing cytoplasm of E. coli trxB gor enabled proper disulfide formation in vivo. The isolated RAMP2 ECD was purified to homogeneity. Co-expression of a soluble MBP-CLR ECD fusion protein with DsbC in E. coli trxB gor yielded a heterogeneous mixture of species with misfolded ECD. Incubation of affinity-purified MBP-CLR ECD in vitro with purified RAMP2 ECD, DsbC, and glutathione redox buffer promoted proper folding of the CLR ECD and formation of a stable MBP-CLR ECD:RAMP2 ECD complex that was purified by size-exclusion chromatography and which exhibited specific AM binding. Approximately 40mg of highly purified complex was obtained starting with 6L bacterial cultures for each protein. The methodology reported here will facilitate structure/function studies of the AM receptor.
Mesoscopic Fluctuations of Elastic Cotunneling in Coulomb Blockaded Quantum Dots

We report measurements of mesoscopic fluctuations of elastic cotunneling in Coulomb blockaded quantum dots. Unlike resonant tunneling on Coulomb peaks, cotunneling in the valleys is sensitive to charging effects. We observe a larger magnetic field scale for the cotunneling (valley) fluctuations compared to the peaks, as well as an absence of ``weak localization'' (reduced conductance at $B\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$) in valleys. Cotunneling fluctuations remain correlated over several valleys while peak conductance correlation decreases quickly.
Total synthesis of (±)-paniculide-a

Abstract An efficient synthesis of the paniculide A precursor 4 has been achieved beginning with 3-methylglutaric anhydride, and utilizing as the key step an intramolecular Diels-Alder reaction of an acetylenic oxazole to give a 2-methoxyfuran. Acid hydrolysis then provided the requisite butenolide ring characteristic of the paniculides.
The role of pharmacotherapy and catheter-based intervention in the management of patients with non-ST-segment elevation acute coronary syndromes.

The American College of Cardiology/American Heart Association Task Force on Practice Guidelines has published recommendations regarding diagnosis and treatment of patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). The acute ischemia pathway presented in these guidelines encompasses both an early invasive strategy and an early conservative strategy. The recognition of the role of platelet biology in ACS led to the development of glycoprotein (GP) IIb/IIIa receptor antagonists for the management of patients with NSTE ACS. Based on studies of risk stratification models for NSTE ACS, as well as a better understanding of the underlying biology of serum markers of myocardial necrosis, refinements have been made in identifying which patients benefit most from intravenous platelet receptor antagonism and the use of early invasive strategies. The available data suggest that for the NSTE ACS patient with intermediate- to high-risk features, the early initiation of intravenous platelet receptor antagonism with a small molecule GP IIb/IIIa receptor blocker, followed by timely cardiac catheterization with attempts at revascularization is the superior management strategy. In the majority of cases where such patients present to a facility without cardiac catheterization capability, stabilization with antiplatelet, antithrombotic, and antiischemic therapies should be undertaken prior to timely tertiary percutaneous coronary intervention referral.
End-to-end fair rate optimization in wired-cum-wireless networks

In this paper, we address the end-to-end rate optimization problem in a wired-cum-wireless network, where CSMA/CA based wireless LANs extend a wired backbone and provide access to mobile users. The objective is to achieve proportional fairness amongst the end-to-end sessions in the network. Since the network contains wireless links whose attainable throughput is a (non-convex and non-separable) function of MAC protocol parameters, the problem requires joint optimization at both the transport and the link layers. A dual-based algorithm is proposed in this paper to solve this cross-layer rate optimization problem. It is implemented in the distributed manner, and works at the link layer to adjust scheduling rates for the wireless links in the basic service sets, and at the transport layer to adjust end-to-end session rates. We prove rigorously that the proposed algorithm converges to the globally optimal rates. Simulation results are provided to support our conclusions.
Children of Incarcerated Parents: How a Mentoring Program Can Make a Difference

In spite of the rapid increase in the U.S. prison population, with subsequent increase of parent-prisoners, there are few requirements that social systems serving children take note of a parent's incarceration. Thus the special needs of children of incarcerated parents are almost invisible. Given the multiple risks that these children experience, it is critical to recognize community programs that can help bridge the difficulties children face during their parents' incarceration. This article reports the outcome of a mentoring program specifically targeted to these children. The results show that although mentoring cannot address all of the issues facing these children, it can produce positive outcomes that may mitigate some of the risks associated with being a child of an incarcerated parent.
Impact of impinging wall jet on color Doppler quantification of mitral regurgitation.

BACKGROUNDIn clinical color Doppler examinations, mitral regurgitant jets are often observed to impinge on the left atrial wall immediately beyond the mitral valve. In accordance with fluid dynamics theory, we hypothesized that a jet impinging on a wall would lose momentum more rapidly, undergo spatial distortion, and thus have a different observed jet area from that of a free jet with an identical flow rate.METHODS AND RESULTSTo test this hypothesis in vivo, we studied 44 patients with mitral regurgitation--30 with centrally directed free jets and 14 with eccentrically directed impinging wall jets. Maximal color jet areas (cm2) (with and without correction for left atrial size) were correlated with mitral regurgitant volumes, flow rates, and fractions derived from pulsed Doppler mitral and aortic forward flows. The groups were compared by analysis of covariance. Mean +/- SD mitral regurgitant fraction, regurgitant volume, and mean flow rate averaged 37 +/- 17%, 3.06 +/- 2.65 l/min, and 147 +/- 118 ml/sec...
The generation of diazirinone: a computational study

Abstract Computational studies indicate that the reaction of p -nitrophenoxyfluorodiazirine with fluoride ion should generate diazirinone. However, fluoride ion also catalyzes the decomposition of diazirinone to carbon monoxide and nitrogen, so that the diazirinone is likely to be unstable to the conditions used to generate it.
Metabolic fractionation of C13 & C12 in plants

C/sup 13//C/sup 12/ ratio analyses of chemical fractions from several plant phyla show that in all cases the lipid fraction is enriched in C/sup 12/ compared to the whole plant. The C/sup 13//C/sup 12/ r atio of the plant lipids corresponds roughly to the C/sup 13//C/sup 12/ ratio of petroleums. The C/sup 12/ enrichment in petroleums a compared to present day plants can be explained if selective preservation of plant lipids occurred during the sedimentation process. The degree of C/sup 12/ enrichment in the plant lipid fraction is inversely related to the amount of lipid in the plant. The C/sup 12/ enrichment which occurs in plant lipids may be balanced by the C/sup 13/ enrichment which occurs in respired CO/sub 2/. Isotope selection at the level of acetate or pyruvate is a possible mechanism for explaining our results. (auth)
Charge separation from drops of electrolyte on a heated metal surface

Abstract A model for the charging of a sessile drop on a heated metal surface is developed and the results compare favorably with experiment.
Sacral Nerve Stimulation to Treat Nonobstructive Urinary Retention in Women

Nonobstructive urinary retention is an uncommon finding in women that may represent a difficult management problem for urologists and patients. Pharmacotherapy and urethral dilatation are rarely successful, and clean intermittent catheterization may be cumbersome. Those patients who cannot self-catheterize may be subjected to an indwelling catheter. Sacral nerve stimulation is a minimally invasive treatment for nonobstructive urinary retention, with 10 years of data documenting its long-term safety and efficacy. This minimally invasive treatment can restore satisfactory voiding in most patients and should be a routine part of treatment for this rare but important condition.
Solvent extraction of transfer ribonucleic acids.

Abstract Mixed tRNA's from E. coli are selectively extracted from an aqueous solution containing 0.05 M Tris-HCl, 0.01 M MgCl2, and various concentrations of NaCl with an organic solution containing Adogen 464, a tetraalkylammonium chloride, in Freon 214. The tRNA's are completely extracted into the organic phase at NaCl concentrations below 0.1 M, and the extraction coefficient [ E α 0 = A 260 ( org ) A 260 ( aq ) ] decreases with increasing NaCl concentration. The extraction coefficient increases with increasing temperature in the range 10° to 25°C. Consequently, the tRNA's can be stripped from the organic phase with an aqueous solution of higher salt concentration, e.g., 0.5 M NaCl, or at lower temperature, e.g., 5°C. Other parameters influencing the extraction coefficient are extractant concentration in the organic phase and Mg2+ concentration in the aqueous phase. With other conditions constant, the extraction coefficients for 0.1 M and 0.5 M amine solutions are 3.75 and 15.1, respectively. The usable extraction range occurs at higher NaCl concentrations in the absence of MgCl2. The order of extractability of the specific tRNA's can be correlated with the order of elution from a reversed-phase chromatographic column. The tRNA's that elute first are also generally the least extractable, while those that elute last are the most extractable. A tRNAPhe product having 399 pmoles A 260 unit has been prepared by a simple batch-type extraction. The major active contaminants were tRNATyr ( 75 pmoles A 260 unit ) and tRNATrp ( 56 pmoles A 260 unit ). It was possible to obtain a product which assayed approximately 800 pmoles A 260 unit for tRNAPhe by combining batch extraction with gel permeation chromatography.
Application of Theory and Research in Fishery Management of the Laurentian Great Lakes

Abstract The Great Lakes have a high potential for the conduct of research and useful application of research findings, but the history of the Great Lakes indicates that extensive research and intensive management have failed to prevent deterioration of the fisheries. At times the research was not done before a loss occurred, or did not provide the information needed to solve a problem, or was not interpreted to indicate a need for corrective action. Three examples are used to illustrate these problems: (1) Sea lamprey (Petromyzon marinus) research was not initiated until 50 years after the destructiveness of the sea lamprey was recognized, and control measures were not developed or applied until species most vulnerable to the lamprey had been greatly reduced or eliminated. (2) Most research on the alewife (Alosa pseudoharengus) has been directed toward determining why large numbers of alewives die during the spring and summer, but has not provided the information most urgently needed by management to use...
Growth of Differentiated Ovine Tracheal Epithelial Cells In Vitro

Culture of ovine tracheal epithelial cells is a useful tool for conducting various in vitro studies. We describe herein an in vitro technique and the conditions for culturing primary epithelial cells derived from tracheas of adult sheep. Ovine tracheas were surgically removed from 2- to 3-month-old healthy sheep and tracheal epithelial cells were isolated by 0.15% pronase digestion. After epithelial cells isolation, a Millicell insert with porous membrane was coated with 0.05% human placental collagen and the epithelial cells were added to the membrane. To create an air-liquid interface environment for the cells, the apical compartment of the membrane containing the tracheal epithelial cells was left exposed to 5% CO(2) at 37 degrees C for 2 days then increased to 9% CO(2) while cells in the basolateral compartment underneath the membrane contained the growth medium necessary for cells nourishment. Pepsin digestion was more effective in reducing the number of fibroblasts than other procedures. Cells were allowed to grow for 6-7 days to form a confluent monolayer and nearly 21 days for cilia formation on the apical surface as determined by light microscopy of haematoxylin and eosin-stained sections of membranes. In order to further confirm the epithelial origin of cells, cells were stained for cytokeratin antigen by immunohistochemistry. Most ciliated epithelial cells were immunoreactive for cytokeratin. This is the first report of differentiated ovine tracheal epithelial cells growth and isolation. This technique can be used in numerous in vitro investigative studies in ovine species as an animal model for human disease.
Glutamate uptake blockade induces striatal dopamine release in 6-hydroxydopamine rats with intrastriatal grafts: evidence for host modulation of transplanted dopamine neurons.

The transplantation of fetal dopamine neurons has previously been shown to ameliorate locomotor deficits in laboratory animals with nigrostriatal dopamine lesions. These studies have also demonstrated a reinstatement of striatal dopamine synthesis and release associated with the graft-to-host fiber innervation. More recent studies in the intact striatum indicate that striatal dopamine release can be regulated by corticostriatal glutamatergic projections. In the present study we hypothesized that secretion of dopamine by grafted neurons may also be regulated by similar mechanisms. To test this hypothesis we have measured dopamine release in the striatum of rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal pathway and grafts containing dopamine neurons. Intrastriatal dopamine levels were determined using methods of in vivo microdialysis. The administration of dihydrokainic acid, an inhibitor of glutamate uptake, resulted in the release of striatal dopamine in grafted and normal rats. In contrast, dopamine was not detectable in animals with 6-OHDA lesions alone. Additional studies were conducted to determine the type of glutamate receptor mediating the release of striatal dopamine. Kainic acid administration into the perfusate of the dialysis probe resulted in the release of striatal dopamine in a dose-dependent fashion in both grafted and normal rats. N-methyl-d-aspartate had no effect on dopamine release except at abnormally high concentrations. These results demonstrate that dopamine neurons which are transplanted into the striatum of rats with 6-OHDA lesions become functionally incorporated into the neural circuitry of the host brain, and that the release of dopamine by grafted neurons can be regulated by afferent fibers from the host brain. These host-to-graft mechanisms regulating the release of dopamine may also play an important role in ameliorating motor deficits in parkinsonian patients with intrastriatal grafts of dopamine neurons.
Presidential address: Micropaleontology, Past and Future: ABSTRACT

This paper traces the rise of interest in microscopic fossils from the sixteen sixties when Leeuwenhoek's development of the forerunner of the microscope made their study possible, through the several centuries of their sporadic investigation in the interests of pure research by small groups of scientists, to the birth of the utilitarian science of micropaleontology a quarter century ago. The developmental phases of the science are then outlined, and the progressive multiplication of the micropaleontologic groups studied is considered. The origin and growth of micropaleontology as a subject in university curricula is reviewed, and suggestions are made for the future expansion and improvement of training in this special field. In addition, consideration is given to the general academic background the prospective paleontologist should acquire in order best to serve his science as well as prove most valuable to the organization which purchases his services. Finally the future of the science of micropaleontology is analyzed, and suggestions are made for the direction of efforts into new lines of investigation which may prove profitable in enlarging the scientific scope of the field and thus in enhancing its commercial significance. End_of_Article - Last_Page 936------------
Ultra-Low Voltage Wide Bandwidth Electro-optic Modulators

Wide bandwidth, ultra-low voltage modulators based on substrate removal technology and loaded line traveling wave electrodes are presented. Drive voltage product is 0.06 V-cm and 2 mm long devices have electrical-to-electrical bandwidths exceeding 80 GHz.
Toward an Understanding of the Chemical Etiology for DNA Minor-Groove Recognition by Polyamides

Crescent-shaped polyamides composed of aromatic amino acids, i.e., 1-methyl-1H-imidazole Im, 1-methyl-1H-pyrrole Py, and 3-hydroxy-1H-pyrrole Hp, bind in the minor groove of DNA as 2 : 1 and 1 : 1 ligand/DNA complexes. DNA-Sequence specificity can be attributed to shape-selective recognition and the unique corners or pairs of corners presented by each heterocycle(s) to the edges of the base pairs on the floor of the minor groove. Here we examine the relationship between heterocycle structure and DNA-sequence specificity for a family of five-membered aromatic amino acids. By means of quantitative DNase-I footprinting, the recognition behavior of polyamides containing eight different aromatic amino acids, i.e., 1-methyl-1H-pyrazole Pz, 1H-pyrrole Nh, 5-methylthiazole Nt, 4-methylthiazole Th, 3-methylthiophene Tn, thiophene Tp, 3-hydroxythiophene Ht, and furan Fr, were compared with the polyamides containing the parent-ring amino acids Py, Im, and Hp for their ability to discriminate between the four Watson-Crick base pairs in the DNA minor groove. Analysis of the data and molecular modeling showed that the geometry inherent to each heterocycle plays a significant role in the ability of polyamides to differentiate between DNA sequences. Binding appears sensitive to changes in curvature complementarity between the polyamide and DNA. The Tn/Py pair affords a modest 3-fold discrimination of T⋅A vs. A⋅T and suggests that an S-atom in the thiophene ring prefers to lie opposite T not A.
Oxyradical reactions: from bond-dissociation energies to reduction potentials

Destructive radical reactions involve alkykl, alkoxyl and alkylperoxyl radicals, as well as alkylhydroperoxides. From bond energies the following reduction potentials vs NHE at neutral pH are derived: Esuo'(RO./ROH) = 1.6 V, Eo'(ROO./ROOH) = 1.0 V, Eo'(ROOH/RO., H2;0) = 1.9 V, and the two-electron reduction potential Eo'(ROOH/ROH, H2O) = 1.7 V. Hydrogen abstraction from a bis-allylic methylene group by alkoxyl and alkylperoxyl radicals is favourable with Gibbs energies of −23 and −9 kcalmol, respectively. Similarly, alkoxyl radicals can oxidize alkylhydroperoxides, ΔGo' = −14 kcalmol.
Marketing strategy: An essential component of business development for academic health centers

Abstract Background: Historically, academic health centers (AHCs) have detached themselves from commercialism and entrepreneurism, viewing these activities as being inconsistent with many of their core academic values. Word-of-mouth promotion was their primary, if not sole, marketing strategy. Less emphasis was placed on preparing, pricing, distributing, and promoting these services to targeted audiences. Understanding customers’ needs was not a top priority. Methods: The marketing strategies and tools currently being developed and utilized by AHCs were reviewed. Results: In an effort to attract customers and win contracts, AHCs are aggressively marketing themselves by designing new services, promoting those services much more intensely, restructuring the entire distribution system that delivers those services, and crafting pricing strategies that build in flexibility. With growing frequency, these marketing tactics are part and parcel of a carefully crafted data-driven strategic plan designed to meet the business-development goals of the institution. Conclusions: In order to carry out their missions, AHCs have recognized that they can no longer rest on their “ivory tower” laurels. They must learn how to market themselves in a market economy.
Early results and follow-up of balloon angioplasty for branch pulmonary artery stenoses.

Abstract Two hundred eighteen balloon angioplasty procedures were performed in 135 patients with branch pulmonary artery stenoses from June 1984 to February 1989. Arteries were dilated in patients with tetralogy of Fallot (n = 49), tetralogy of Fallot/pulmonary atresia (n = 64), isolated peripheral pulmonary artery stenoses (n = 58) and “other” lesions (the majority had truncus arteriosus or single ventricle and surgically induced pulmonary artery stenoses (n = 47). Mean age at dilation was 6.6 ± 6.3 years (range 1 month to 38.5 years). The mean diameter of the lesion increased from 3.8 ± 1.7 to 5.5 ± 2.1 mm with dilation (p = 0.0001). The overall success rate was 58% (127 of 218 dilations), assessed by the following criteria: an increase ≥50% of predilation diameter, an increase >20% in flow to the affected lung or a decrease >20% in systolic right ventricular to aortic pressure ratio. Success did not correlate with patient age. Mean balloon to artery ratio was higher in successful (4.2) than in failed (3.0) angioplasty procedures (p = 0.0001). There were four early deaths: two of the patients had pulmonary artery rupture with angioplasty performed
Perceptions of the academic environment: A national survey

Two randomly selected subsets of dermatology training program graduates who passed qualifying examinations for certification by the American Board of Dermatology in 1984 and 1989 received a questionnaire concerning their perceptions of academic teaching positions. Approximately one third responded. Those in private practice indicated financial constraints, lack of "control," and the requirement to be "political" as negative factors in academic centers, whereas those in academic positions indicated the inordinate amount of time that was required to achieve academic goals as the major negative factor. Both groups believed that the opportunity to teach and intellectual challenge were the most valued elements in academic careers. There was considerable misunderstanding among all respondents about the diversity of goals, methods, and opportunities that are found in many academic programs.