cssi/SciSciGPT-SciSciNet huggingface dataset:
Theoretical and Experimental Aspects of Protein Folding

This article is based on the second and third of four lectures that I presented at the International Summer School of Biophysics. The first lecture, entitled “Recent developments in the theory of water, aqueous solutions and protein hydration,” has already been summarized in several review articles (Scheraga, 1979; Paterson et al., 1981; Nemethy et al., 1981), and the fourth lecture, entitled “Enzyme — substrate interactions,” has likewise been summarized in two recent reviews (Pincus and Scheraga, 1981; Scheraga et al., 1982). In the two lectures constituting this article, we describe some of our theoretical and experimental work designed to gain an understanding of the interactions that lead to the observed conformational behavior of biological macromolecules, either as individual molecules or as complexes with other molecules. The theoretical aspects of the problem are dealt with first; this is then followed by a discussion of experimental studies on protein conformation.
The Impact of Firm Identity on Accountants’ Error Reporting Decisions: An Experimental Investigation

Recent regulatory and professional developments have increased the frequency with which public accountants work and interact with professionals from other accounting firms. We posit that competitive pressures are particularly salient when clients retain accountants from different firms to perform audit, tax, and/or consulting services, and examine whether the disclosure decisions of professional accountants could be biased in a manner consistent with these pressures. We conduct two experiments in settings where professional services are commonly split among different firms: the provision of non-audit tax services and the completion of a group audit. We find that, when clients retain different accounting firms to perform professional services, accountants share information about possible financial statement errors in ways that protect their competitive advantage over their rivals, although the specific effects differ between the audit and tax settings. Our results have important implications for financial reporting quality and provide new insights regarding the effects of interfirm collaboration.
Ergonomics in endoscopic sinus surgery.

Purpose of review Awareness of ergonomics is growing into surgical specialties including otolaryngology. Most otolaryngologists experience occupational physical discomfort, and daily incorporation of standard ergonomic principles may alleviate some of this pain. Recent findings Further demonstration of surgery-related physical discomfort has been documented based on surveys of general otolaryngologists and subspecialty rhinologists. One study utilized surface electromyography to document physical findings directly associated with the endoscopic sinus surgery procedure. However, relatively little work has been published on interventions to relieve task-related pain and body discomfort in rhinology. Summary Surgeon fatigue and bodily injury is a surprisingly frequent occurrence and is more likely to occur in procedures that are mentally challenging, prolonged, and require the surgeon to operate in a fixed position. Endoscopic sinus and skull base surgeons appear particularly susceptible to task-related physical discomfort, and incorporation of ergonomic principles should be a priority.
HgTe/CdTe and HgSe/CdX (X = S, Se, and Te) Core/Shell Mid-Infrared Quantum Dots

Mid-infrared core/shell quantum dots are synthesized starting with HgTe and HgSe cores which emit around 5 μm with interband and intraband transitions, respectively. HgTe/CdTe and HgSe/CdX (X = S, Se, and Te) are grown by colloidal atomic layer deposition at room temperature. HgSe/CdSe is also grown by hot-injection. For films of the core/shells, even a two-monolayer shell leads to a vastly improved stability against annealing, with no observable changes up to the alloying temperatures of ∼180 °C for HgTe/CdTe and ∼250 °C for HgSe/CdX. The improvement in the photoluminescence remains however small for all systems. In this study across interband and intraband emissions, the brightest emitter at 5 μm is the intraband transition of HgSe/CdSe with a quantum yield of ∼10–3.
Overdose Deaths Involving Fentanyl and Fentanyl Analogs — New York City, 2000–2017

Unintentional drug overdose deaths have climbed to record high levels, claiming approximately 70,000 lives in the United States in 2017 alone (1). The emergence of illicitly manufactured fentanyl* (a synthetic, short-acting opioid with 50-100 times the potency of morphine) mixed into heroin, cocaine, and counterfeit pills, with or without the users' knowledge, has increased the risk for fatal overdose (2,3). The New York City (NYC) Department of Health and Mental Hygiene (DOHMH) conducts routine overdose mortality surveillance by linking death certificates with toxicology findings from the NYC Office of the Chief Medical Examiner (OCME). A 55% increase in the rate of fatal drug overdose in NYC was observed from 2015 to 2017, resulting in the highest number of overdose deaths recorded since systematic reporting began in 2000. Toxicology data indicate that this unprecedented increase in overdose deaths is attributable to fentanyl. Early identification of increased fentanyl involvement enabled DOHMH to respond rapidly to the opioid overdose epidemic by increasing awareness of the risks associated with fentanyl and developing effective risk reduction messaging. These results strongly suggest that, wherever possible, jurisdictions should consider integrating toxicology findings into routine overdose surveillance and work with local medical examiners or coroners to include fentanyl in the literal text on death certificates.
3 Developmental Epidemiology

Introducing epidemiology as the study of health and illness in human populations, we discuss what questions modern epidemiology addresses, the key methods it uses, and how these methods can be applied to developmental psychopathology. A short history of how child psychiatric epidemiology has grown into developmental epidemiology illustrates society's changing concerns about child mental health. We describe some of the ways in which developmental epidemiology is branching out into related areas: life course and intergenerational epidemiology; global epidemiology; genetic epidemiology; the study of burden of disease, including cost-benefit analysis; and the use of epidemiologic designs to test hypotheses about causation. Finally, we note that developmental epidemiology extends the range of translational epidemiology. We make the case that (1) the goal of epidemiological research is disease prevention; (2) understanding the development of a disease and intervening to prevent and control it are equally important aspects of epidemiological research; (3) understanding the development of a disease may point to different kinds of intervention at different stages in the developmental process; and (4) understanding individual development is a critical part of understanding and intervening in the disease process because both risk for and expression of disorder change over the life course. Keywords: development; epidemiology; psychiatry; risk; public health; mechanisms
Managing Frontal Sinusitis from Systemic Inflammatory Disease

In this chapter, we outline the systemic diseases that can be encountered in patients with chronic frontal sinusitis, starting with identification of clinical patterns. Next, we compare and contrast the various conditions that may be associated with chronic frontal sinusitis, including allergic fungal sinusitis, aspirin-exacerbated respiratory disease, common variable immune deficiency, eosinophilic granulomatosis with polyangiitis, granulomatosis with polyangiitis, HIV, IgG4-related disease, odontogenic sinusitis, cystic fibrosis, primary ciliary dyskinesia, sarcoidosis, and cocaine-induced midline destructive lesions. We discuss examination features as well as laboratory and radiographic findings. Finally, we review in detail the management options specific to the identified systemic diseases.
Phase II Study of Preoperative Chemoradiotherapy with Oxaliplatin, Infusional 5-Fluorouracil, and Cetuximab Followed by Postoperative Docetaxel and Cetuximab in Patients with Adenocarcinoma of the Esophagus: A Trial of the ECOG-ACRIN Cancer Research Group (E2205)

Background A standard approach to treating resectable esophageal adenocarcinoma is chemoradiotherapy (CRT) followed by surgery; however, recurrence is common. To improve this, we designed a single-arm, phase II trial that added an epidermal growth factor receptor (EGFR) inhibitor, cetuximab (C), to CRT, with the hypothesis that EGFR inhibition would improve pathologic complete response (pCR) rate. Materials and methods We aimed to increase the pCR rate from 25% to 45%. A Simon two-stage design (α and β of 0.10) required pCR/enrolled 5/18 for stage 1 and 14/40 total. CRT: oxaliplatin 85 mg/m2 days 1, 15, and 29; infusional 5-fluorouracil 180 mg/m2 /24 hours × 35 days; C 400 mg/m2 day 1 then 250 mg/m2 days 8, 15, 22, and 29 and radiation (intensity modulated radiotherapy [IMRT] allowed) 180 cGy/day × 25 fractions (Monday through Friday). Following esophagectomy, adjuvant chemotherapy (CT): weekly docetaxel 35 mg/m2 and C 250 mg/m2 5 out of 6 weeks for two cycles. Results Of 21 eligible patients enrolled, 17 had surgery; 4 died before operation (due to pulmonary embolism 4 days after CRT, G3 diarrhea, progressive disease during CRT, sepsis/hypoxia during CRT, and acute respiratory distress syndrome [ARDS]). pCR = 7/17. Three postoperative deaths due to ARDS resulted in seven total study-related deaths. Of the 14 remaining patients, 12 started and completed adjuvant CT. Two of seven patients with pCR died, both of ARDS. Out of the 21 eligible subjects in this study, 13 have died and 8 remain alive. The use of IMRT did not correlate with ARDS. Conclusion This regimen demonstrated promising activity. Toxicity was significant, with seven study-related deaths leading to closure after stage 1. All postoperative deaths were due to ARDS. This regimen is not recommended. Implications for practice Esophageal cancer is a disease with a high death rate. The current treatment involves giving chemotherapy plus radiation followed by surgery, but this cures only a quarter of patients. In order to improve survival, better treatments are needed. This trial evaluated the addition of a novel drug, cetuximab, to chemotherapy plus radiation. Unfortunately, the side effects were too great and the study was stopped early.
Testing Differential Item Functioning in Small Samples.

AbstractDifferential item functioning (DIF) is a pernicious statistical issue that can mask true group differences on a target latent construct. A considerable amount of research has focused on eva...
Treatment of Opioid Use Disorder in Pediatric Medical Settings

The purpose of this review is to examine the impact of the opioid epidemic in adolescents and young adults and recent findings regarding the treatment of opioid use disorder (OUD) in pediatric medical settings. Existing guidelines for the treatment of chronic pain in adults are not intended to be applied to adolescents, who arguably may need different interventions that balance the need to mitigate the long-term impact of chronic pain with the need to limit opioid misuse. Screening, brief intervention, and referral to treatment is an important upstream strategy to prevent opioid misuse in youth. Medications such as buprenorphine, naltrexone, and methadone are important treatment options for youth with OUD but remain underutilized in this population. More research is needed to better understand how to best prevent opioid misuse and treat OUD in adolescents and young adults.
Developing high performance concrete for precast/prestressed concrete industry

Abstract High performance concrete (HPC) is a new class of concrete that has superior characteristics compared to conventional concrete. Despite of its superior characteristics, HPC is not widely used in local and international markets due to its high constituent materials cost. This paper presents the research done to develop economic HPC mixes using local materials and conventional mixing and curing techniques. HPC characteristics were attained using supplementary cementitious materials as silica fume and class C fly in partial replacement of Portland cement. Superplasticizers were used to maintain a high flowing ability using a low water-to-powder ratio. Concrete mixes were produced using a high energy mixer to maintain sufficient mix consistency. As a result, concrete mixes with 24 -h compressive strength of 70 MPa and 28-day strength of 105 MPa were produced. Concrete samples tested for expansion using accelerated mortar bar test (AMBT) showed that developed concrete is not susceptible to alkali-silica reaction. Improved characteristics can be used in improving the performance of concrete construction projects, reduce required maintenance, and increase construction projects life-span.
The coarticulation of vowels and stop consonants

Abstract: Although[± voice] is a significant phonological feature for distinguishing between /b,d,g/ and /p,t,k/ in English at a highly abstract level, it is not necessarily the case that this feature is significant at the phonetic level. That is, it cannot account for the fact that some “voiced” stops exhibit no vocal cord vibration during stop closure. Rather, aspiration seems to be the significant perceptual cue in English for distinguishing between “voiced” and “voiceless” stops before a stressed vowel at the phonetic level. The most significant perceptual cue for distinguishing between “voiced” and “voiceless” stops in post-vocalic position, however, is not so clear. The length of the preceding vowel has been posited as the most significant perceptual cue, yet such a solution does not account for the possibility of more than two systematic degrees of vowel length in English. Instead it seems that the perceptual cue correlating with the phonological feature [± voice] for determining the voice value of stops in post-vocalic position is directly linked to the manner of termination of the preceding vowel. That is, a gradually terminated vowel signals a following “voiced” stop and an abruptly terminated vowel indicates the presence of a following “voiceless” stop. Such a solution accounts for both the variability of vocal cord vibration during stop closure and vowel lengthening before “voiced” stops in English.
Diagnosis of Unanticipated Plant Component Faults in a Portable Expert System

We describe the first-principles-based PRODIAG expert system for on-line plant-level diagnosis of component faults in thermal-hydraulic processes. This diagnostic system combines the concepts of fundamental physical principles and function-oriented diagnosis in a qualitative reasoning framework and structures these concepts into three independent knowledge bases. PRODIAG has the unique ability to diagnose unanticipated (unforeseen) component faults and can be ported across different processes/plants through modifications of only input data files containing the appropriate process layout information. Simulation tests for two plant systems with transient data generated with the Braidwood Nuclear Power Plant full-scope training simulator confirm the unique capabilities of PRODIAG.
Women’s Representation in the Post-Soviet Space: Latvia and Lithuania

Using a most-similar case design to compare Latvia and Lithuania, this study examines the role electoral systems play in affecting greater representation of women in post-Soviet democracies. After Latvia’s most recent election, Latvia demonstrated a much higher percentage of women in its parliament (31%) than Lithuania (21%). Interestingly, in spite of having higher descriptive representation, Latvia has no quotas or women's organizations/caucuses while Lithuania implements voluntary quotas and has a prevalent women's caucus. This study advances an institutional argument, hypothesizing that the Latvian parliament's higher percentage of women can be attributed to its proportional representation electoral system. Lithuania has a mixed system that has favored a majoritarian pole, which in turn, has adversely affected women’s electoral success. In many ways, women’s substantive representation in Latvia and Lithuania is only marginally different. However, in regard to the sheer number of women in parliament, the difference between Lithuania and Latvia proves relatively marked. The Latvian and Lithuanian cases demonstrate that proportional representation electoral systems are more favorable to women candidates than mixed systems, even in the absence of quotas and a women’s movement and particularly in the context of post-Soviet democracies
[Malaria epidemiological situation in Wuzhou City, Guangxi Zhuang Autonomous Region from 1950 to 2015].

OBJECTIVE To review and investigate the malaria control history of Wuzhou City, Guangxi Zhuang Autonomous Region from 1950 to 2015, so as to provide the evidence for future malaria control and surveillance. METHODS The data of malaria control in Wuzhou City from 1950 to 2015 were collected and analyzed. RESULTS In 1950 decade, the malaria incidence in Wuzhou City was 1 435.55/100 000, higher than the average level in Guangxi, and the mortality of malaria was 0.95/100 000. The malaria incidence of local residents was reduced to 3.61/100 000 in 1979 and no local malaria case was found since. The imported malaria cases were found in Wuzhou City since 1980, and were more than local cases since 1981. In recent five years, 87.50% (7/8) of imported malaria cases were from south-east Asia. CONCLUSIONS Wuzhou City has reached the national criterion of malaria elimination, but the imported malaria is the recent threat. The surveillance and control work of malaria should be strengthened.
Positive or Negative? Implementation Processes and Pitfalls of Preoperative SARS-CoV-2 Testing at a Single Academic Institution.

Abstract Background Preoperative screening and testing for SARS-CoV-2 are important aspects of reopening perioperative and procedural sites to elective cases after the initial wave of the novel coronavirus pandemic. However, given that modern healthcare has never experienced a pandemic of this magnitude, rapid operationalization of mass testing presents unique challenges. We aim to highlight our experiences and challenges for preoperative SARS-CoV-2 testing. Methods We describe implementation of widespread screening tools and preoperative polymerase chain reaction (PCR) testing in a single, academic medical center. Results As of August 2020, we have been able to achieve an over 90% success rate in preoperative SARS-CoV-2 PCR testing for both outpatient and inpatient procedures. However, there are certain challenges in obtaining high levels of compliance both on individual and institutional levels. Conclusions Instituting preoperative SARS-CoV-2 testing and maintaining high levels of compliance is possible in the midst of a fluctuating pandemic.
Simulation of Interaction between an Operator and an Exoskeleton

This paper discusses the hardware structure of the human–machine interface of industrial exoskeletons and the corresponding mathematical models for selecting the optimal parameters of the human–machine interface and for developing the control algorithms. A four-stage algorithm for planning the angle of rotation of the operator’s back when performing a load lifting operation using polynomials of the seventh order is proposed. The movement of the human–exoskeleton system with a focus on the hip joint and lumbar spine was simulated. The effect of the parameters of the mathematical model of the human–exoskeleton system, including the operator’s muscular system, on the accuracy of reproducing operator’s movements by the exoskeleton is shown.
To Disclose or Conceal? Workplace Disability and Eldercare-Related Disclosure Decision-Making Strategies:

Using qualitative methods, this study explored workplace disclosure decisions made by employees caring for children and younger adults with disabilities or special healthcare needs and compared the...
Water-borne corticosterone assay is a valid method in some but not all life-history stages in Northern Leopard Frogs.

Abstract There is a particular need to develop conservation tools for use in amphibian populations, which are declining rapidly. Glucocorticoid hormones like corticosterone (CORT) are often used as biomarkers of amphibian stress. A relatively new method of assessing CORT in amphibians is to measure CORT concentrations in water that has held amphibians (water-borne (WB) CORT). Here, we tested whether WB CORT is a valid measure of CORT in larval and metamorphic Northern Leopard Frogs (Lithobates pipiens). We assessed whether levels of WB CORT are different among groups of animals that should have different levels of CORT due to a handling challenge, a pharmacological challenge (ACTH), or developmental stage. We also assessed whether WB CORT was correlated with plasma CORT within individuals. Results indicated that measurement of WB CORT is valid in prometamorphic tadpoles because injection with ACTH increased WB CORT, and WB CORT and plasma CORT levels were correlated within an animal in most cases. However, were unable to fully validate the use of WB CORT in metamorphic frogs (metamorphs) because although injection with ACTH elevated levels of WB CORT, WB CORT was not correlated with plasma CORT within individual metamorphs. Also, there was no correlation between WB CORT and plasma CORT in early stage (premetamorphic) tadpoles or tadpoles undergoing metamorphic climax, indicating that WB CORT is not sensitive enough to detect natural variation of organismal CORT in these groups. Together, results indicated that WB CORT is a valid method of assessing plasma CORT in Northern Leopard Frogs, but only for some life-history stages. Our results illustrate the importance of carefully validating the use of WB CORT for appropriate interpretation of results.
Urinary amino acid excretion: Comparison of normal individuals and patients with bladder cancer

The excretion levels of urinary amino acids obtained from acid hydrolysates were studied by gas chromatographic analysis in 29 normal individuals and 118 patients with bladder carcinoma. Leucine and isoleucine excretion were elevated in patients with bladder carcinoma as compared with normal subjects under the same experimental condition. Mathematical computer-assisted programs developed to aid in determining clusters of amino acid variables suggested that excretion of glycine, leucine, proline, and glutamic acid in men and concentrations of valine, serine, aspartic acid, phenylalanine, and lysine in women vary according to the invasiveness of the disease. These findings suggest that measurements of urinary amino acids may provide a useful parameter for the detection and aid in the staging of bladder carcinoma.
Teachers’ Patterns of Implementation of an Evidence-Based Intervention and Their Impact on Student Outcomes: Results from a Nationwide Dissemination over 24-Months Follow-Up

More information is needed about factors influencing real-life implementation and program impact of interventions effective in controlled study conditions. Ongoing national implementation of an evidence-based HIV prevention program targeting grade 6 students in The Bahamas offers the opportunity to examine patterns of implementation and relate them to student outcomes. Data were collected from 208 grade 6 teachers, 75 grade 7 teachers and 4411 grade 6 students followed over 2 years. Mixed-effects modeling analysis examined the association of teachers’ patterns of implementation with student outcomes. High quality program implementation in grade 6 (high implementation dosage and fidelity) was significantly related to student outcomes six and 18 months post-intervention. Quality of implementation of the booster session in grade 7 was also significantly related to student outcomes in grade 7. Quality of delivery of the brief booster session a year after initial implementation is important in maintaining or resetting the student outcome trajectory.
Organization of Photoreceptor Signaling Complexes

Phototransduction is a prototypical G-protein-coupled signaling pathway in both vertebrates and invertebrates. Phototransduction in Drosophila is one of the fastest G-protein-coupled signaling pathways known, taking less than 20 ms from light activation to maximum response. This high speed of signaling is primarily due to the incorporation of signaling components into multi-protein complexes. Signaling complexes bring components into close proximity, promoting rapid interaction and ensuring the proper subcellular localization of components. The central organizer of these complexes is the protein i nactivation- n o- a fterpotential- D (INAD), which functions as a scaffold for multiple signaling components. The eye-specific INAD protein, which consists almost entirely of p ostsynaptic-density-95/ D iscs-large/ Z O1 (PDZ) domains (PDZ1 to PDZ5 from N- to C-terminus), has been found to interact with multiple members of the phototransduction cascade. Studies using co-immunoprecipitation, GST-pull-down, ligand overlay, and yeast two-hybrid assays, in both Drosophila and Calliphora , have revealed three major proteins that interact with INAD that include the effector PLCβ, the light-activated ion channel transient receptor potential (TRP), and the eye-PKC required for normal deactivation. Each PDZ domain appears to be specific for a particular protein partner. PDZ3 has been shown to bind the TRP channel most likely via a site in the C-terminal 14 residues of TRP. INAD-signaling complexes have been proposed to form multimers, making up larger transduction units, or transducisomes. Transducisomes may promote the coordinated gating of TRP channels that open in response to the activation of one rhodopsin molecule. Several potential scenarios could underlie the multimerization of INAD-signaling complexes. One possibility is that INAD homomultimerizes through a PDZ–PDZ interaction.
Administrative Law, Public Administration, and the Administrative Conference of the United States

From its birth administrative law has claimed a close connection to governmental practice. Yet as administrative law has grown and matured it has moved further away from how agencies actually function. In particular, as many have noted, administrative law ignores key administrative dimensions, such as planning, assessment, oversight mechanisms and managerial methods, budgeting, personnel practices, reliance on private contractors, and the like. The causes of administrative law’s disconnect from public administration are complex and the divide is now longstanding, going back to the birth of each as distinct fields. But it is also a growing source of concern, and internal administration is increasingly becoming the linchpin for ensuring accountable government. Enter the Administrative Conference of the United States (ACUS). ACUS represents one of the rare instances in which administrative law and public administration have been linked and is ideally situated to study administrative law’s effects on internal agency operations and assess whether — as well as how — administrative law might be used to improve public administration.
Microblogging for Strengthening a Virtual Learning Community in an Online Course

This paper examines how a microblogging tool (i.e., Twitter) can be effectively used to strengthen a virtual learning community (VLC) in the two sections of a fully online graduate course. Students in this course were consisted of K-12 teachers, school technology specialists, corporate trainers, and military personnel. The microblogging activities were designed to allow quick peer interaction to build the momentum of social learning in the VLC. In this study, we collected quantitative data on sense of community through a Likert scale survey, and rich qualitative data on students’ perception about microblogging activities. It was found that students’ sense of community was generally high and students were positive about their microblogging experiences. In addition, microblogging was found to be useful and valuable in sustaining students’ learning by doing such as sharing real-world design examples, critiquing design examples with technical knowledge learned in class, and quick and short commenting with peer support in a VLC. Based on the findings, the authors aim to provide design suggestions for educators and instructional designers to incorporate this social web tool in strengthening virtual learning communities in a meaningful and engaging way. https://doi.org/10.34105/j.kmel.2011.03.039
Perturbation of a nonionic microemulsion by the introduction of a charged surfactant: I. Light scattering

Abstract A nonionic microemulsion with a small fraction of its nonionic surfactant, Brij 96, replaced by sodium oleate was used to vary the charge on the presumed microemulsion droplets in a controllable fashion. Cloud points and other evidence indicate that the mixed microemulsion was formed. The molecular weight and second virial coefficient of the droplets were measured as a function of added salt and showed that the molecular weight of the ionized microemulsion was only slightly changed from the nonionic case, while the changes in second virial coefficient could be described by a hard sphere plus double-layer potential. The particles were shown to undergo ordering at very low salt concentrations.
The Heart of Addiction

The Heart of Addiction, based on more than twenty-five years of clinical practice by distinguished psychiatrist Dr. Lance Dodes, presents a radical approach to understanding and harnessing the emotional forces that drive addictions. Alcoholism and other addictions are among the most important problems we face in our society. Yet, if you look beyond pat ideas about their cause, such as "alcoholism is a disease," nobody has really had an answer for why people with addictive behaviors continue to repeat them in the face of their awful consequences. This book offers an answer to the core "Why?" question of alcoholism and other addictions. Dr. Dodes sets out to change the way completely we treat alcoholism and other addictions, including compulsive gambling and sexual addiction. He describes how all addictions have at their heart certain emotional/ psychological factors that, once understood, can be successfully managed. He shows how these factors can be turned to good use to find exactly what alternatives will work for you as an individual. Filled with compelling case studies, Dr Dodes provides the keys to mastering addictions and answers the critical questions: Why do we feel the impulse? Why do we feel it when we do? How can we find what else to do in that critical moment? [publisher description]
Vascular defects in human endometrium caused by intrauterine contraceptive devices. An electron microscope study.

Abstract Endometrial blood vessels from hysterectomized uteri of women using intrauterine contraceptive devices (IUDs) were, examined in the electron microscope to search for the location and cause of IUD-associated uterine hemorrhage. The findings revealed vascular gaps in a small percentage of superficial vessels and these gaps were formed from degenerated endothelial cells. Mechanical surface erosion of the endometrium was judged not to be the mechanism of bleeding because the surface epithelium usually was found to be intact by gross and microscopic examination in spite of variable degrees of surface degeneration and denudation. Tentatively, biochemical induction of vascular permeability also did not seem likely. An explanation for IUD-induced uterine bleeding based upon pressure generated between the IUD and the contracting uterus is proposed. Observation of erythrocytes within vessel gaps supports the feasibility that these gaps provide a route for the escape of blood from endometrium exposed to IUDs.
How Best to Look Forward

Useless Arithmetic. Why Environmental Scientists Can9t Predict the Future. By Orrin H. Pilkey and Linda Pilkey-Jarvis. Columbia University Press, New York, 2007. 246 pp. $29.50, £19. ISBN 9780231132121. Critiquing a series of examples, the authors argue that many quantitative models only provide a false sense of security and unwarranted confidence in predictions.
Association of Child Poverty, Brain Development, and Academic Achievement

Importance Children living in poverty generally perform poorly in school, with markedly lower standardized test scores and lower educational attainment. The longer children live in poverty, the greater their academic deficits. These patterns persist to adulthood, contributing to lifetime-reduced occupational attainment. Objective To determine whether atypical patterns of structural brain development mediate the relationship between household poverty and impaired academic performance. Design, Setting, and Participants Longitudinal cohort study analyzing 823 magnetic resonance imaging scans of 389 typically developing children and adolescents aged 4 to 22 years from the National Institutes of Health Magnetic Resonance Imaging Study of Normal Brain Development with complete sociodemographic and neuroimaging data. Data collection began in November 2001 and ended in August 2007. Participants were screened for a variety of factors suspected to adversely affect brain development, recruited at 6 data collection sites across the United States, assessed at baseline, and followed up at 24-month intervals for a total of 3 periods. Each study center used community-based sampling to reflect regional and overall US demographics of income, race, and ethnicity based on the US Department of Housing and Urban Development definitions of area income. One-quarter of sample households reported the total family income below 200% of the federal poverty level. Repeated observations were available for 301 participants. Exposure Household poverty measured by family income and adjusted for family size as a percentage of the federal poverty level. Main Outcomes and Measures Children’s scores on cognitive and academic achievement assessments and brain tissue, including gray matter of the total brain, frontal lobe, temporal lobe, and hippocampus. Results Poverty is tied to structural differences in several areas of the brain associated with school readiness skills, with the largest influence observed among children from the poorest households. Regional gray matter volumes of children below 1.5 times the federal poverty level were 3 to 4 percentage points below the developmental norm ( P P P Conclusions and Relevance The influence of poverty on children’s learning and achievement is mediated by structural brain development. To avoid long-term costs of impaired academic functioning, households below 150% of the federal poverty level should be targeted for additional resources aimed at remediating early childhood environments.
Mapping the thermal structure of solid-media pressure assemblies

The refractory oxides MgO and Al2O3 are the most commonly used insulator/filler materials in solid-media pressure assemblies. These oxides react with one another at high temperatures and pressures, forming a well-defined layer of spinel (~MgAl2O4) at the contact. The spinel layer widens in proportion to the square root of time at a rate that also depends systematically upon temperature and pressure. On the basis of 44 piston-cylinder runs spanning 1,200–2,000 °C and 1.0–4.0 GPa, we present a general relationship describing the width (ΔX) of the spinel layer as a function of time (t, in s), temperature (T, in K) and pressure (P, in GPa): \(\Delta {\rm X} = \left[ {{\rm 8}{\rm .58} \times {\rm 10}^{{\rm 11}} \cdot \exp \left( { - 48865/{\rm T} - 2.08 \cdot {\rm p}^{1/2} } \right) \cdot {\rm t}} \right]^{1/2}\) . If the pressure and duration of an experiment are known (as is usually the case) this calibration makes it possible to calculate the temperature to within a few degrees at any location in a solid-media assembly where MgO and Al2O3 are in contact (at T above ~1,200 °C) – simply by measuring the width of the spinel layer with an optical microscope. Application of this "reaction-progress" thermometer to the 13- and 19-mm diameter piston-cylinder assemblies used in the RPI lab confirms generally parabolic axial T gradients with acceptably broad hot spots. Three-dimensional maps of the 19-mm assembly reveal a radial component to the thermal field, with somewhat higher temperatures near the graphite heating element (i.e., a saddle-shaped hot region). Two exploratory experiments in a multi-anvil apparatus at 14 GPa (1,700 and 1,975 °C) confirm that the reaction-progress technique will work at pressures well above 4 GPa. The piston-cylinder-based calibration predicts ΔX to within a factor of two in the two multi-anvil runs, and relative changes in T along the assembly can be readily mapped. However, additional high-pressure calibration points will be needed before the thermometer can be used in quantitative multi-anvil applications. The spinel reaction-progress thermometer is easily implemented, and should allow other researchers to map the thermal structures of their own assemblies in a single experiment with one thermocouple.
PREPARATION OF 5,6-O-ISOPROPYLIDENE-L-ASCORBIC ACID.

Die Synthese der 5,6-o-Isopropyliden-l-ascorbinsaure mit Hilfe von Chlorwasserstoffgas wird beschrieben.
The Optimal Power Assignment for Cooperative Hybrid-ARQ Relaying Protocol

In this work, we consider the problem of assigning optimal transmission power sequence for cooperative hybrid automatic-repeat-request (H-ARQ) relaying protocol over quasi-static Rayleigh fading channels. We try to determine the optimal power sequence by minimizing the average total transmission power that we analyzed in our previous work in [10]. However, the closed-form expression of the average total power consumption of the cooperative H-ARQ relaying protocol is complicated in general, so we develop first in this work a simple approximation of the average total transmission power that is tight at high SNR. Then, based on the asymptotically tight approximation, we are able to identify the sequence of power values that minimizes the average total power consumption of the cooperative H-ARQ relaying protocol for any given targeted outage probability. In particular, we derive a set of equations that describe the optimal power level in each (re)transmission and enable its recursive calculation with fixed searching complexity. When the maximum number of (re)transmissions allowed in the protocol is $L = 2$, we have a closed-form result for the optimal transmission power sequence. The optimal power assignment solution reveals that conventional equal power assignment scheme is not optimal in general. Extensive simulation and numerical results are provided to illustrate and validate the theoretical results.
Effect of hypoxia on traumatic brain injury in rats: Part 2. Changes in high energy phosphate metabolism.

Abstract The effect of different degrees of hypoxia on phosphate metabolism in the brains of impact-injured rats was studied using in vivo phosphorus-31 magnetic resonance (P-31 MR) spectroscopy. Sequential changes in P-31 MR spectra within 60 minutes of insult were compared among rats with hypoxia alone, impact injury alone, or a combined impact-hypoxic insult. Hypoxia alone (PaO2 of 40 mm Hg for 30 minutes) caused no remarkable changes in phosphorus spectra except a decrease in intracellular pH. In impact-injured rats, the concentration of inorganic phosphate (Pi) increased, but signals for phosphocreatine (PCr) and beta-adenosine triphosphate (beta-ATP) did not change, and the ratio of PCr/Pi changed only slightly to 7% below control value. When rats with a fluid percussion impact injury of 5 atm were subjected to hypoxic conditions of a PaO2 of 40 mm Hg for 15 minutes, the PCr/Pi ratio decreased by 14%, a value significantly below that of the impact alone group (P less than 0.05). After longer periods of hypoxia (PaO2 of 40 mm Hg for 30 minutes) in impact-injured rats, there were marked increases of Pi and significant decreases in signals for PCr and beta-ATP, which caused a marked decrease in the PCr/Pi ratio to 39% below control values (P less than 0.001). Milder hypoxia (PaO2 of 50 mm Hg for 30 minutes) plus impact injury caused smaller changes in high energy metabolite concentrations, and the PCr/Pi ratio decreased to 15% below control values.(ABSTRACT TRUNCATED AT 250 WORDS)
Problem orientation is a new approach to surgical education.

Abstract Background : There is increasing interest in educational methods that are loosely aggregated under the title of problem-based learning (PBL), but it remains unclear whether PBL is as successful as its conventional predecessor in transmitting factual information. Materials and methods : The authors designed and implemented a PBL curriculum for a third-year surgical clerkship, then prospectively compared that technique with the conventional format. Each student's subject-related knowledge was assessed with a specifically tallored 195-question written exam and correlated with National Board of Medical Examiners shelf exams. Student and faculty responses to the technique were also sought and tabulated. Results : Student and faculty responses to PBL were uniformly positive. We were unable, however, to demonstrate effects on our evaluation instruments. Neither individual student performance nor grouped scores differed based on the mode of presentation. Conclusion : A PBL curriculum generates both student and faculty enthusiasm. Unfortunately, this does not translate into more efficient transmission of knowledge.
Signaling pathways downstream of P2 receptors in human neutrophils

Extracellular nucleotides stimulate human neutrophils by activating the purinergic P2Y2 receptor. However, it is not completely understood which types of G proteins are activated downstream of this P2 receptor subtype. We investigated the G-protein coupling to P2Y2 receptors and several subsequent signaling events. Treatment of neutrophils with pertussis toxin (PTX), a Gi protein inhibitor, caused only ∼75% loss of nucleotide-induced Ca2+ mobilization indicating that nucleotides cause Ca2+ mobilization both through Gi-dependent and Gi-independent pathways. However, the PLC inhibitor U73122 almost completely inhibited Ca2+ mobilization in both nucleotide- and fMLP-stimulated neutrophils, strongly supporting the view that both the PTX-sensitive and the PTX-insensitive mechanism of Ca2+ increase require activation of PLC. We investigated the dependence of ERK phosphorylation on the Gi pathway. Treatment of neutrophils with PTX caused almost complete inhibition of ERK phosphorylation in nucleotide or fMLP activated neutrophils. U73122 caused inhibition of nucleotide- or fMLP-stimulated ERK phosphorylation, suggesting that although pertussis toxin-insensitive pathways cause measurable Ca2+ mobilization, they are not sufficient for causing ERK phosphorylation. Since PLC activation leads to intracellular Ca2+ increase and PKC activation, we investigated if these intracellular events are necessary for ERK phosphorylation. Exposure of cells to the Ca2+ chelator BAPTA had no effect on nucleotide- or fMLP-induced ERK phosphorylation. However, the PKC inhibitor GF109203X was able to almost completely inhibit nucleotide- or fMLP-induced ERK phosphorylation. We conclude that the P2Y2 receptor can cause Ca2+ mobilization through a PTX-insensitive but PLC-dependent pathway and ERK phosphorylation is highly dependent on activation of the Gi proteins.
Nonequilibrium adhesion patterns at lipid bilayer junctions

With lipid bilayer-bilayer junctions in mind as model systems for the study of cell-cell junctions, we have examined adhesion between simple lipid membranes using fluorescence resonance energy transfer (FRET) and fluorescence interference contrast microscopy (FLIC) to map the interfacial topography. The contact can take the form of uniform adhesion, with an intermembrane separation of nanometers, or nonuniform adhesion, in which blisters hundreds of nanometers in height coexist with tight adhesion zones. We find that blisters can result as a consequence of rapid interbilayer contact induced by osmotic shock. We develop a model for the formation and stabilization of the blisters, confirming that these phenomena are governed mainly by hydrodynamic flow in the intermembrane space.
Placental defects in α7 integrin null mice

The α7β1 integrin is a heterodimeric transmembrane receptor that links laminin in the extracellular matrix to the cell cytoskeleton. Loss of the α7 integrin chain results in partial embryonic lethality. We have previously shown that α7 integrin null embryos exhibit vascular smooth muscle cell defects that result in cerebral vascular hemorrhaging. Since the placenta is highly vascularized, we hypothesized that placental vascular defects in α7 integrin null embryos may contribute to the partial embryonic lethality. Placentae from embryonic day (ED) 9.5 and 13.5 α7 integrin knockout embryos showed structural defects including infiltration of the spongiotrophoblast layer into the placental labyrinth, a reduction in the placental labyrinth and loss of distinct placental layers. Embryos and placentae that lacked the α7 integrin weighed less compared to wild-type controls. Blood vessels within the placental labyrinth of α7 integrin null embryos exhibited fewer differentiated vascular smooth muscle cells compared to wild-type. Loss of the α7 integrin resulted in altered extracellular matrix deposition and reduced expression of α5 integrin. Together our results confirm a role for the α7β1 integrin in placental vascular development and demonstrate for the first time that loss of the α7 integrin results in placental defects.
Book Reviews Featuring a Special Essay by Herbert Jack Rotfeld

Textbooks and Research Journals Conventional wisdom holds that marketing textbooks are based on established marketing concepts. Readers assume that the contents of these books reliably summarize research findings to provide foundational information for students. In what is assumed to be a virtuous and reciprocal relationship, knowledge is generated in research, published in journal articles, and then collected and summarized in textbooks. The process sometimes is reversed when journal articles appeal to textbooks for authority. However, the relationship between texts and research is not always virtuous. For example, in their study of marketing texts, Armstrong and Schultz (1993) collected 566 normative statements about pricing, communications, and product or distribution decisions that were not supported by empirical evidence. Nine of the statements were judged to be “nearly correct” when their wording was reversed! In this review, I explore the ambivalent and often perverse relationship between knowledge generating (research) and knowledge disseminating (textbooks) activities in a process I call the “textbook effect.” The textbook effect refers to (1) the embedding of old, defunct, unsubstantiated theories in textbooks and (2) the effect such embedding has on practice and research. Although my point is a general one, for the sake of illustration I take up a particular case of the impact of the textbook effect on the body of research referred to as “fear appeals.”