cssi/SciSciGPT-SciSciNet huggingface dataset:
Association Between Race and Ethnicity in the Delivery of Regional Anesthesia for Pediatric Patients: A Single-Center Study of 3189 Regional Anesthetics in 25,664 Surgeries

Background Racial and ethnic disparities in health care are well documented in the United States, although evidence of disparities in pediatric anesthesia is limited. We sought to determine whether there is an association between race and ethnicity and the use of intraoperative regional anesthesia at a single academic children's hospital. Methods We performed a retrospective review of all anesthetics at an academic tertiary children's hospital between May 4, 2014, and May 31, 2018. The primary outcome was delivery of regional anesthesia, defined as a neuraxial or peripheral nerve block. The association between patient race and ethnicity (white non-Hispanic or minority) and receipt of regional anesthesia was assessed using multivariable logistic regression. Sensitivity analyses were performed comparing white non-Hispanic to an expansion of the single minority group to individual racial and ethnic groups and on patients undergoing surgeries most likely to receive regional anesthesia (orthopedic and urology patients). Results Of 33,713 patient cases eligible for inclusion, 25,664 met criteria for analysis. Three-thousand one-hundred eighty-nine patients (12.4%) received regional anesthesia. One thousand eighty-six of 8884 (13.3%) white non-Hispanic patients and 2003 of 16,780 (11.9%) minority patients received regional anesthesia. After multivariable adjustment for confounding, race and ethnicity were not found to be significantly associated with receiving intraoperative regional anesthesia (adjusted odds ratios [ORs] = 0.95; 95% confidence interval [CI], 0.86-1.06; P = .36). Sensitivity analyses did not find significant differences between the white non-Hispanic group and individual races and ethnicities, nor did they find significant differences when analyzing only orthopedic and urology patients, despite observing some meaningful clinical differences. Conclusions In an analysis of patients undergoing surgical anesthesia at a single academic children's hospital, race and ethnicity were not significantly associated with the adjusted ORs of receiving intraoperative regional anesthesia. This finding contrasts with much of the existing health care disparities literature and warrants further study with additional datasets to understand the mechanisms involved.
Neurocognitive mechanisms of mindfulness-based interventions for addiction

Abstract Recent developments in cognitive neuroscience provide insight into the neurocognitive deficits underlying addiction. At the same time, mindfulness meditation practices have emerged as promising treatments for addictive disorders. This chapter first presents evidence supporting mindfulness-based interventions (MBIs) as effective therapies for addictive disorders. Next, “top-down” and “bottom-up” mechanisms through which MBIs exert their therapeutic effects on addictive behavior are detailed. A neurobiological framework is integrated throughout the text, highlighting parallels between the restorative effects of mindfulness practice on the brain and dysregulated neural functions undergirding addictive behaviors. Finally, MBIs are considered as means of recovery enhancement in the broader context of long-term addiction treatment.
Progestational and androgenic substances tested on the highly proliferated vaginal epithelium of surgical castrates

Abstract The effects of 17-alpha-hydroxyprogesterone caproate, chemically pure progesterone, and anhydrohydroxyprogesterone on the highly proliferated vaginal epithelium and endometrium of 6 surgical castrates were evaluated and compared. It has been found that dosages of progestational agents sufficient to induce complete secretory changes in the endometrium indistinguishable from those in the secretory phase of a normal menstrual cycle also induce so-called luteal changes in the vaginal epithelium.
Customer Databases for Small Firms: Maximizing the Power of Your Marketing

This article describes how and why a small business can take advantage of the benefits which will accrue from the creation and use of a custon1er database. What information may be useful to capture (or buy) about your customer, and how that information can be used to improve your n1arketing efforts and subsequent "bottom line'' is presented How to create (or evaluate for purchase of) a database, and how to maintain your database lo preserve its accuracy and value is explained. Information technology is transforming the business game for small firms today. The importance of database marketing as a cost-effective tool which small firms should be utilizing cannot be understated or overlooked.
Aging and Cognition

Cognitive functions develop and change across the lifespan. Previous research has documented how normal age-related processes negatively affect cognition. Tests of memory performance, decision-making, processing speed, and executive functioning, including inhibition, set-shifting, and problem-solving ability, have been shown to steadily decline across the lifespan, with noticeable deficits clearly occurring by age 50. Although the data consistently demonstrate a decline, interindividual differences have shown great variability in the onset and extent of these changes. Additionally, investigators in the field of cognitive rehabilitation have provided support for the view that cognitive fitness can be enhanced by engaging in mentally stimulating activities and/or aerobic exercise and that such activity may delay cognitive decline and even prevent dementia.
Gene therapy approaches to restore chloride homeostasis for treating neuropathic pain

Abstract Chronic neuropathic pain is a debilitating condition that remains difficult to treat. Intracellular chloride homeostasis in mature neurons is critical for normal synaptic inhibition by GABA and glycine, and chloride dysregulation in primary sensory neurons and spinal dorsal horn neurons is closely involved in neuropathic pain. In this chapter, we review the function of two cation-chloride cotransporters, Na+-K+-Cl− cotransporter 1 (NKCC1) and K+-Cl− cotransporter 2 (KCC2), expressed in the spinal cord and their involvement in the diminished synaptic inhibition at the spinal cord level in neuropathic pain. We describe the contribution of NMDA receptor-calpain signaling to nerve injury-induced KCC2 proteolysis and downregulation in the spinal dorsal horn in neuropathic pain. We also discuss the therapeutic potential of intrathecal delivery of the KCC2 gene using viral vectors for restoring chloride homeostasis and for treating neuropathic pain.
Omission of Axillary Lymph Node Dissection is Associated with Inferior Survival in Breast Cancer Patients with Residual N1 Nodal Disease Following Neoadjuvant Chemotherapy

The appropriateness of substituting sentinel lymph node dissection (SLND) and regional nodal irradiation (RNI) for axillary lymph node dissection (ALND) in patients with residual lymph node (LN) disease following neoadjuvant chemotherapy (NAC) is unknown. We used the National Cancer Database (NCDB) to compare survival following SLND and ALND in breast cancer patients with residual LN disease. We analyzed NCDB patients, treated between 2006 and 2014, with cT1–3, cN1, cM0 breast cancer and residual disease in 1–3 axillary LNs (ypN1) following NAC. Patients were grouped into those who received SLND (defined as removal of ≤ 4 LNs) and RNI, or ALND and RNI. Patients were matched for all patient, tumor, and treatment characteristics. We identified 1313 eligible patients in the ALND group and 304 patients in the SLND group. For the matched cohorts, SLND was associated with significantly lower survival in both univariate and doubly robust multivariable analyses (MVA) (HR 1.7, 95% CI 1.3–2.2, P < 0.001 for MVA), with estimated 5-year OS of 71%, compared with 77% in the ALND group (P = 0.01). Exploratory subgroup analyses showed that SLND was comparable with ALND in patients with luminal A or B tumors with a single metastatic LN (HR 1.03, 95% CI 0.59–1.8, (P = 0.91). Our analysis suggests that, while an ALND may not be needed for patients with limited residual nodal burden and biologically favorable tumors, SLND should not be routinely substituted for ALND in patients with ypN1 disease following NAC until its efficacy is confirmed by prospective trials.
Automated breast ultrasound: Supplemental screening for average-risk women with dense breasts.

Abstract Objective We review ultrasound (US) options for supplemental breast cancer screening of average risk women with dense breasts. Conclusion Performance data of physician-performed handheld US (HHUS), technologist-performed HHUS, and automated breast ultrasound (AUS) indicate that all are appropriate for adjunctive screening. Volumetric 3D acquisitions, reduced operator dependence, protocol standardization, reliable comparison with previous studies, independence of performance and interpretation, and whole breast depiction on coronal view may favor selection of AUS. Important considerations are workflow adjustments for physicians and staff.
Race Differences in Resilience Among Older Adults with Chronic Low Back Pain.

Introduction Racial minorities are disproportionally affected by pain. Compared to non-Hispanic Whites (NHWs), non-Hispanic Blacks (NHBs) report higher pain intensity, greater pain-related disability, and higher levels of mood disturbance. While risk factors contribute to these disparities, little is known regarding how sources of resilience influence these differences, despite the growing body of research supporting the protective role of resilience in pain and disability among older adults with chronic pain. The current study examined the association between psychological resilience and pain, and the moderating role of race across these relationships in older adults with chronic low back pain (cLBP). Methods This is a secondary analysis of the Adaptability and Resilience in Aging Adults (ARIAA). Participants completed measures of resilience (ie, gratitude, trait resilience, emotional support), as well as a performance-based measure assessing lower-extremity function and movement-evoked pain. Results There were 45 participants that identified as non-Hispanic White (NHW) and 15 participants that identified as non-Hispanic Black (NHB). Race was a significant correlate of pain outcomes with NHBs reporting greater movement-evoked pain (r = 0.27) than NHWs. After controlling for relevant sociodemographic characteristics, measures of movement-evoked pain were similar across both racial groups, F (1, 48) = 0.31, p = 0.57. Moderation analyses revealed that higher levels of gratitude (b = −1.23, p = 0.02) and trait resilience (b = −10.99, p = 0.02) were protective against movement-evoked pain in NHWs. In contrast, higher levels of gratitude were associated with lower functional performance in NHBs (b = −0.13, p =0.02). Discussion These findings highlight racial differences in the relationship between resilience and pain-related outcomes among older adults with cLBP. Future studies should examine the potential benefits of targeted interventions that improve resilience and ameliorate pain disparities among racial minorities.
Methods for population-based eQTL analysis in human genetics

Gene expression is a critical process in biological system that is influenced and modulated by many factors including genetic variation. Expression Quantitative Trait Loci (eQTL) analysis provides a powerful way to understand how genetic variants affect gene expression. For genome wide eQTL analysis, the number of genetic variants and that of genes are large and thus the search space is tremendous. Therefore, eQTL analysis brings about computational and statistical challenges. In this paper, we provide a comprehensive review of recent advances in methods for eQTL analysis in population-based studies. We first present traditional pairwise association methods, which are widely used in human genetics. To account for expression heterogeneity, we investigate the methods for correcting confounding factors. Next, we discuss newly developed statistical learning methods including Lasso-based models. In the conclusion, we provide an overview of future method development in analyzing eQTL associations. Although we focus on human genetics in this review, the methods are applicable to many other organisms.
Case Studies of Cybercrime and its Impact on Marketing Activity and Shareholder Value

Cybercrime, also called e-crime, costs publicly traded companies billions of dollars annually in stolen assets and lost business. Cybercrime can totally disrupt a company’s marketing activities. Further, when a company falls prey to cyber criminals, this may cause customers to worry about the security of their business transactions with the company. As a result, a company can lose future business if it is perceived to be vulnerable to cybercrime. Such vulnerability can lead to a decrease in the market value of the company, due to legitimate concerns of financial analysts, investors, and creditors. This study examines 10 case studies of publicly traded companies affected by cybercrime, and its impact on marketing activity and shareholder value. The study also describes some of the major types of cybercrime. Results indicate that costs of cybercrime go beyond stolen assets, lost business, and company reputation; cybercrime has a significant negative effect on shareholder value.
A New Framework for Power Control in Wireless Data Networks: Games, Utility, and Pricing

We develop a new framework for distributed power control for wireless data based on the economic principles of utility and pricing. Utility is defined as the measure of satisfaction that a user derives from accessing the wireless data network. Properties of utility functions are introduced and a specific function, based on throughput per terminal battery life-time including forward error control, is presented and shown to conform to those properties. Users enter into a non-cooperative game to maximize their individual utilities by adjusting their transmitter powers. A unique Nash equilibrium for the above game is shown to exist but is not Pareto efficient. A pricing function is then introduced which leads to Pareto improvements for the non-cooperative game.
Marine enzymes from seafood by-products

Publisher Summary Enzyme technology has been used extensively in the food processing industry including fish processing. Enzymes are used as processing aids and can be produced from by-product material from both new and traditional fish processing operations. Marine enzymes have drawn the attention of numerous researchers as they can possess unique specificity and characteristics. Enzyme recovery from seafood by-products could also help the environmental and ethical concerns surrounding the discards and improve the bottom line for seafood companies wishing to exploit new technologies and markets. This chapter discusses the current literature on the extraction and purification of various marine enzymes and their potential use and limitations in their utilization. Extractable enzymes from seafood and seafood by-products include digestive and cellular proteinases, extracellular gastric proteinases, chitinases, lipases, phospholipases, transglutaminases, polyphenoloxidase, and others. Marine-based enzymes often have unique physical, chemical, and catalytic properties compared to corresponding enzymes from terrestrial animals and plant sources. Therefore, enzyme extraction and utilization from seafood by-products include enzymes from both solid and liquid waste streams that are often discarded or traditionally processed into fish feed or fertilizer. Seafood by-products include viscera, skins, bones, heads, and frames from fish as well as shells and exoskeletons from shellfish in both traditional and modern processing operations.
Relationships of testicular iron and ferritin concentrations with testicular weight and sperm production in boars

The inverse relationship of testicular size and circulating follicle-stimulating hormone (FSH) concentrations has been documented, and accompanying this relationship is the change in color of the parenchymal tissue of the testes. Large testes (300 to 400 g) are pink to light red and small testes (100 g) are dark maroon with color gradations for weights in between. It was hypothesized that this color most likely represented an iron protein. Chromatographic analysis of testicular tissue indicated that the Fe was associated primarily with ferritin, and immunohistochemistry showed that Leydig cells were the primary location of ferritin storage within the testes. Concentrations of Fe and ferritin were higher in small testes and decreased as testes weight increased (P < 0.05). As testicular Fe concentrations increased, daily sperm production (DSP) and total DSP declined (P < 0.05). Genotyping six generations of Meishan x White composite boars (n = 288) for a quantitative trait locus that is indicative of elevated FSH and small testes in boars indicated that the Meishan genotype had elevated testicular iron concentrations and darker color in conjunction with reduced total DSP (P < 0.01). It is not thought the elevated iron concentrations affect testicular weights but are probably a result of elevated FSH and FSH inducement of Fe transport. The storage of Fe in Leydig cells may provide a reservoir of Fe for easy access by Sertoli and germ cells, but still provide a degree of protection to germ cells from ionic iron.
After the End: Recovery from Extinction

Mass extinctions of many plants and animals were a regular part of prehistory. How the ecosystems of Earth recovered from these disasters is just beginning to be understood (see report on p. [1327][1] by Jablonski et al .), but may teach valuable lessons for the preservation of our present biodiversity, as Erwin explains in a commentary in this issue. [1]: http://www.sciencemag.org/cgi/content/short/279/5355/1327
An Evolutionary Algorithm for Single Objective Nonlinear Constrained Optimization Problems

This paper presents research into an evolutionary algorithm that utilizes the coevolution of feasible and infeasible solutions in solving constrained optimization problems. The evolution of these populations occurs through the use of traditional and specially designed operators that allow for crossover to occur in each of the populations as well as across the two populations. The cross population crossover allows for the information contained in the infeasible solutions to be utilized in the search for the optimal solution.
A rectangular cavity for cell phone antenna efficiency measurement

Electromagnetic cavities can be used to measure antenna efficiency. Enclosing an antenna within a conducting rectangular or spherical cavity can eliminate the radiation resistance from the impedance without changing the loss resistance of the antenna. The cavity size should avoid both the disturbance of the field near the antenna and the cavity's resonance. The efficiency of the antenna is calculated from the measurement of its input resistance inside the cavity and in free space. The paper uses the same approach to compute cell phone antenna efficiency. First, the size of the rectangular cavity is chosen and its resonant frequencies closest to the US cellular band (824-894 MHz) are determined. Then, a monopole antenna is placed inside the cavity in order to excite a coupling between the antenna and the cavity at those resonant frequencies. A simple model of a bar cell phone is then placed inside the cavity, and the changes in the coupling are analyzed. Finally, a cell phone with its antenna connected to a coaxial cable is placed in the cavity, and the input resistance is measured. Efficiency values measured from the cavity are compared to the values obtained by the radiation pattern integration method. The results show that if a cavity is chosen appropriately, it can effectively be used for measurement of cell phone antenna efficiency.
Central pacinian neurofibroma of the maxilla

Abstract A case of central neurofibroma of the maxilla with pacinian corpuscle histodifferentiation is presented. A possible cause is cited.
A Spectral-Knowledge-Based Approach for Urban Land-Cover Discrmination

A prototype expert system was developed to demonstrate the feasibility of classifying multispectral remotely sensed data on the basis of spectral knowledge. The spectral expert was developed and tested with Thematic Mapper Simulator (TMS) data having eight spectral bands and a spatial resolution of 5 m. A knowledge base was devloped that describes the target categories in terms of characteristic spectral relationships. The knowledge base was developed under the following assumptions: the data are calibrated to ground reflectance, the area is well illuminated, the pixels are dominated by a single category, and the target categories can be recognized without the use of spatial knowledge. Classification decisions are made on the basis of convergent evidence as derived from applying the spectral rules to a multiple spatial resolution representation of the image. The spectral expert achieved an accuracy of 80-percent correct or higher in recognizing 11 spectral categories in TMS data for the Washington, DC, area. Classification performance can be expected to decrease for data that do not satisfy the above assumptions as illustrated by the 63-percent accuracy for 30-m resolution Thematic Mapper data.
Specific inhibition of phorbol diester-induced granulocyte-macrophage progenitor cell (GM-CFU) differentiation by lipoxygenase inhibitors.

Abstract The induction of differentiation of SENCAR murine granulocyte-macrophage precursor cells (GM-CFU) by the tumor-promoting phorbol diester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) was inhibited by agents reported to inhibit specific aspects of arachidonic acid metabolism. These agents included phospholipase A2 inhibitors, and eicosatetraynoic acid (ETYA), a competitive inhibitor of arachidonic acid oxygenases. Whereas inhibitors reported specific for lipoxygenases were also active, no comparable effect was observed for inhibitors of the corresponding cyclooxygenase. These findings are therefore consistent with the hypothesis that induced differentiation of GM-CFU cells is regulated by products of arachidonic acid metabolism formed principally via lipoxygenase activity.
Electrochemistry of Highly Ordered Pyrolytic Graphite Surface Film Formation Observed by Atomic Force Microscopy

In situ electrochemical atomic force microscopy (ECAFM) was used to study the surface films that form on highly ordered pyrolytic graphite (HOPG) electrodes during cathodic polarization in 1 M EC:DMC (1:1) and 1 M EC‐DMC (1.1) electrolytes. Cyclic voltammetry experiments confirmed that distinct reduction reactions occur when the potential of a fresh HOPG electrode is swept from 2.4 to 0.01 V vs. in a Li/HOPG cell. The reactions appear to be irreversible since no evidence of corresponding oxidation reactions was observed. ECAFM results, when combined with slow‐scan cyclic voltammetry data, suggest that different electrochemical reactions are occurring in these two electrolytes. The deposits were found to be several hundreds of nanometers thick. Auger analysis confirmed the presence of elements consistent with electrolyte reduction products. These observations have implications for understanding the formation of a solid electrolyte interphase on HOPG electrodes in lithium‐ion batteries.
The increasing supply of physicians in US urban and rural areas, 1975 to 1988.

BACKGROUND. Despite the rapid growth of the US physician supply since the mid-1970s, it remains unclear whether physicians have spread into the most rural areas of the country. This report examines the urban-rural distribution of physicians between 1975 and 1988. METHODS. A county-based typology of the urban-rural continuum was employed to examine trends in the supply of nonfederal primary care physicians, specialist physicians, and osteopaths. RESULTS. All urban and rural areas gained physicians during the late 1970s and 1980s. The supply of physicians increased most rapidly in metropolitan counties. Within nonmetropolitan areas, urbanized remote counties became more prominent centers of the physician supply. Osteopaths were more likely to locate in the most rural areas than allopaths. The physician supply in all areas also became more specialized over time. CONCLUSIONS. The rapid growth of the US physician supply was associated with the spread of more practitioners into all parts of the country. However...
Attribution of the Recent Winter Sea Ice Decline over the Atlantic Sector of the Arctic Ocean

AbstractWintertime Arctic sea ice extent has been declining since the late twentieth century, particularly over the Atlantic sector that encompasses the Barents–Kara Seas and Baffin Bay. This sea ice decline is attributable to various Arctic environmental changes, such as enhanced downward infrared (IR) radiation, preseason sea ice reduction, enhanced inflow of warm Atlantic water into the Arctic Ocean, and sea ice export. However, their relative contributions are uncertain. Utilizing ERA-Interim and satellite-based data, it is shown here that a positive trend of downward IR radiation accounts for nearly half of the sea ice concentration (SIC) decline during the 1979–2011 winter over the Atlantic sector. Furthermore, the study shows that the Arctic downward IR radiation increase is driven by horizontal atmospheric water flux and warm air advection into the Arctic, not by evaporation from the Arctic Ocean. These findings suggest that most of the winter SIC trends can be attributed to changes in the large-s...
ATP-Binding Cassette B10 Regulates Early Steps of Heme Synthesis

Rationale:Heme plays a critical role in gas exchange, mitochondrial energy production, and antioxidant defense in cardiovascular system. The mitochondrial transporter ATP-binding cassette (ABC) B10 has been suggested to export heme out of the mitochondria and is required for normal hemoglobinization of erythropoietic cells and protection against ischemia–reperfusion injury in the heart; however, its primary function has not been established. Objective:The aim of this study was to identify the function of ABCB10 in heme synthesis in cardiac cells. Methods and Results:Knockdown of ABCB10 in cardiac myoblasts significantly reduced heme levels and the activities of heme-containing proteins, whereas supplementation with δ-aminolevulinic acid reversed these defects. Overexpression of mitochondrial δ-aminolevulinic acid synthase 2, the rate-limiting enzyme upstream of δ-aminolevulinic acid export, failed to restore heme levels in cells with ABCB10 downregulation. ABCB10 and heme levels were increased by hypoxia,...
PT and CPT quantum mechanics embedded in symplectic quantum mechanics

A real-valued symplectic group underlies the dynamics of quantum-mechanical systems. Exploring the embedding of unitary groups clarifies the relation of non-Hermitian - and -symmetric quantum theories of recent interest. Symmetries of the full dynamical framework are quite rich and reveal new viewpoints on many topics in quantum theory. Transformations mixing 'upper' and 'lower' components of certain symplectic multiplets are indistinguishable from coupling antimatter degrees of freedom. Quantities long identified with physical observables are valid canonical coordinates of the theory, without needing support from measurement doctrine. Dirac's canonical quantization is derived from consistency, and would be redundant as a new postulate. A second-order dynamical framework exists in which observables are just the same as the underlying degrees of freedom.
Ocular distribution of liposome-encapsulated epinephrine and inulin in the albino rabbit

A methodology has been developed to evaluate the disposition of liposome-encapsulated epinephrine and inulin in the conjunctival sac and selected ocular tissues. Relative to inulin, epinephrine effluxed much more rapidly from liposomes and disappeared more rapidly from the tear pool. As a result, liposomes were found to exert opposite effects on the ocular uptake of epinephrine and inulin. Over a period of 45 minutes, the concentration of epinephrine in the eye was 1.5-3 times lower when presented in liposomes than in aqueous solutions. This contrasted with the 3 to 15 fold increase in inulin concentration in the eye from liposomal preparations of the compound. Specifically, much of the increase in inulin concentration in the cornea can be attributed to an increase seen in the epithelium. Despite elevated inulin concentrations in the ocular tissues it bathes, the aqueous humor was devoid of inulin unless the corneal epithelium was physically removed prior to topical dosing. Collectively, these findings su...
A cool flame phenomenon in the combustion of acetylene

Abstract Ignition limits were determined on adding small concentrations of oxygen to heated acetylene in a flow system. A ‘cool flame’ was observed when the reactor contained fresh carbon.
Critical electron-vacancy concentrations and sigma formation in udimet 700

The $gamma$-phase compositions and the $gamma$' volume fractions are tabulated for 12 heats of Udimet 700. Values for the average electron-vacancy concentrations and the critical values for the $gamma$-phase at 870$sup 0$C are also tabulated. The results support a model of Barrows and Newkirk [Met. Trans., 3: 2889 (1972)] in which the $gamma$ phase boundary is described in terms of electron--vacancy concentration and temperature and show that this method can be used with computed $gamma$ matrix compositions. Confidence in this method should increase as further comparisons between observed and predicted sigma forming propensities are carried out for other alloys and when the role of non- transition elements such as Al is better understood. (JRD)
Structure of H-covered Be(0001).

In accord with the inverse bond-order--bond-length correlation expected for group-II elements, linearized augmented-plane-wave (LAPW) calculations show that a 1[times]1 monolayer of H, adsorbed on Be(0001), should cause the outer Be layers' separation to be close to ideal, i.e., to be contracted relative to the substantial expansion seen for clean Be(0001). However, the LAPW work functions, and also the H-induced surface-state and resonance positions calculated for 1[times]1 H overlayers, are in poor agreement with experiment. Based on the known accuracy of LAPW calculations, these disagreements indicate that at monolayer coverage, adsorbed H does not all reside above the outer Be layer.
Structural and spectroscopic studies of selectively B-alkylated derivatives in the dicarbahexaborane (8) cage system

The sodium salt of nido -2,3-(SiMe3)-2,3-C2B4H6 (I) reacts with a number of alkylating agents to give, exclusively, nido -5-(R)-2,3(SiMe3)2-2,3-C2B4H5 (R� /CH3 (II), i-C4H9 (III), CH2CH2Cl, and CH2CH2Br). Further alkylation of III could be accomplished only after removing one of the SiMe3 groups with HCl(g) to produce nido -5-(i-C4H9)-2-(SiMe3)-2,3-C2B4H6 (IV), which could then be deprotonated with NaH and further reacted with the methylating agents MeI or CF3SO3Me to give the dialkylated product, nido 4-(CH3)-5-(i-C4H9)-2-(SiMe3)-2,3-C2B4H5 (V). Further alkylation of the sodium compound of V proved unsuccessful, either no reaction was found or inseparable mixtures were obtained. The overall yield of V was about 20%, based on the starting I. Compound III was found to undergo the typical reactions of deprotonation, to give 1-Na(THF)-5-(i-C4H9)-2,3-(SiMe3)2-2,3-C2B4H4 (VII) and oxidative cage closure, to produce closo -3-(i-C4H9)-1,2-(SiMe3)2-1,2-C2B4H3 (VI). The compounds were characterized by infrared spectroscopy, and by 1 H, 11 B and 13 C NMR spectroscopy. Compound III was further characterized by single crystal X-ray diffraction. Irrespective of the nature of the alkyl group and its location, the 11 B NMR spectra showed the same general pattern, namely, the alkylated boron’s resonance shifts downfield by approximately 10 � /15 ppm, while the other resonance positions show little change. Theoretical chemical shifts using GIOA-HF/6-311G** methods on B3LYP/6-31G* optimized geometries of I � /V ,a s well as several model compounds, were used in interpreting the 11 B NMR spectra. # 2002 Elsevier Science B.V. All rights reserved.
Manifestations of the Landau quantization in type II supercondutors in high magnetic fields

Abstract A brief discussion of the Landau-level states, the structure of the gap function, and the lattice periodic solutions of the Gorkov equations is given in the context of type II superconductivity in the presence of high magnetic fields.
A high efficiency cavity ion source using TIMS for nuclear forensic analysis

Abstract Using a high efficiency cavity interfaced to a ThermoFinnigan ‘Triton’ multi-collector TIMS, a total efficiency (atoms loaded to ions detected) of up to 10% for plutonium, strontium, and neodymium loaded on resin beads introduced into a rhenium cavity are feasible. A quantification limit well below 100 attograms of plutonium (10 4 atoms 239 − 242+244 Pu) can be reported. Furthermore, the achieved accuracy and precision are suitable to gain crucial geolocation information at sub-nanogram concentration for elements like strontium. The use of a high efficiency cavity in combination with a multi-collector TIMS appears to be a promising analytical tool to gain crucial (nuclear) forensic information.
On tests for normality of experimental error in ridge regression

Abstract Considered are tests for normality of the errors in ridge regression. If an intercept is included in the model, it is shown that test statistics based on the empirical distribution function of the ridge residuals have the same limiting distribution as in the one-sample test for normality with estimated mean and variance. The result holds with weak assumptions on the behavior of the independent variables; asymptotic normality of the ridge estimator is not required.
Structural Basis of Lipid-Driven Conformational Changes in the Hyperpolarization-Activated Potassium Channel MVP

DOTAP is a bilayer-forming lipid containing a positively charged trimethyl-ammonium group instead of a negatively charged phosphodiester. When reconstituted in pure DOTAP membranes, KvAP is unable to open due to large positive voltage shifts in its mid-point of activation. Based on these results, it has been hypothesized that non-phosphate lipids stabilize the down (resting) conformation of the voltage sensor. We have tested this idea by studying the influence of non-phospholipids on the gating properties of channels with inverse electromechanical coupling. In contrast to most Kv channels, the pore domain of hyperpolarization-activated channels opens with the downward movement of S4 (at hyperpolarizing potentials). Therefore, for any hyperpolarization-activated channel, reconstitution in DOTAP should stabilize the down state of the VSD, favoring the open state and not the closed state. We carried out a CW-EPR analysis of the local structure and dynamics of the prokaryotic hyperpolarization activated potassium channel MVP, after reconstitution in either PC:PG (3:1) or DOTAP liposomes, in the absence of a resting potential. We focused on residues in the S4, S4-S5 linker, and lower S6 of MVP as a way to monitor the key regions that participate in voltage sensing and gate coupling. In PC:PG phospholipids, the inner bundle gate of MVP is closed, as seen from strong spin-spin coupling between residues lining the S6. In contrast, our findings suggest that DOTAP biases the conformation of the VSD in MVP towards the down state, which leads to a structural reorganization of the lower S5 region and conformational changes in the pore domain. The activation gate displays key hallmarks associated with the open conformation. These lipid-driven structural changes point to a working model for the inverse electromechanical coupling in hyperpolarization-activated channels.
Statistical measure for the sharpness of SEM images

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an important aspect of quality control. The application of Fourier analysis techniques to the analysis of SEM images is useful methodology for sharpness measurement. In this paper, a statistical measure known as the multivariate kurtosis, is proposed as a useful measure of the sharpness of SEM images. Kurtosis is designed to be a measure of the degree of departure of a probability distribution from the Gaussian distribution. It is a function of both the fourth and the second moments of a probability distribution. For selected SEM images, the two- dimensional spatial Fourier transforms were computed. Then the bivariate kurtosis of this Fourier transform was calculated as though it were a probability distribution, and that kurtosis evaluated as a characterization tool. Kurtosis has the distinct advantage that it is a parametric measure and is sensitive to the presence of the high spatial frequencies necessary for acceptable levels of sharpness. The applications of this method to SEM metrology will be discussed.
Amplified voltammetric detection of DNA hybridization via oxidation of ferrocene caps on gold nanoparticle/streptavidin conjugates.

Gold nanoparticle/streptavidin conjugates covered with 6-ferrocenylhexanethiol were attached onto a biotinylated DNA detection probe of a sandwich DNA complex. Due to the elasticity of the DNA strands, the ferrocene caps on gold nanoparticle/streptavidin conjugates are positioned in close proximity to the underlying electrode modified with a mixed DNA capture probe/hexanethiol self-assembled monolayer and can undergo reversible electron-transfer reactions. A detection level, down to 2.0 pM (10 amol for the 5 μL of sample needed) for oligodeoxynucleotide samples was obtained. The amplification of the voltammetric signals was attributed to the attachment of a large number of redox (ferrocene) markers per DNA duplex formed. The ferrocene oxidation current increased with the target concentration and began to level off at a target concentration of 10 nM. An Excellent linearity was found within the range between 6.9 and 150.0 pM and reasonable relative standard deviations (between 3.0 and 13.0%) were obtained. ...
Capillary electrophoresis of heparin and other glycosaminoglycans using a polyamine running electrolyte.

Abstract This study involves the use of polyamines as potential resolving agents for the capillary electrophoresis (CE) of glycosaminoglycans (GAGs), specifically heparin, dermatan sulfate, chondroitin sulfate, over-sulfated chondroitin sulfate (OSCS), and hyaluronan. All of the compounds can be separated from each other with the exception of chondroitin sulfate and hyaluronan. Using optimization software, the final run conditions are found to be 200 mM ethylenediamine and 45.5 mM phosphate as the electrolyte with −14 V applied across a 50 μm ID × 24.5 cm fused silica capillary at 15 °C. The ion migration order, with OSCS as the last instead of the first peak, is in contrast to previous reports using either a high molarity TRIS or lithium phosphate run buffer with narrower bore capillaries. Total analysis time is 12. 5 min and the relative standard deviation of the heparin migration time is about 2.5% ( n = 5). The interaction mechanism between selected polyamines and heparin is explored using conductivity measurements in addition to CE experiments to show that an ion-pairing mechanism is likely.
Special Education and Severe Disabilities in Costa Rica: Developing Inclusion in a Developing Country:

Special education has been part of the Costa Rican public education system for more than 60 years. Approximately 10% of the 75,000 students who receive special services have a severe disability; however, there is a chronic shortage of personnel trained to educate students with significant educational needs. In the last 5 years, Costa Rica has promulgated four educational service models that extend special education expertise: Consulting teachers, educational assistance teams, itinerant teams, and resource centers. These models more equitably distribute the technical skills and knowledge of special education professionals throughout the country. In addition, the Department of Special Education has developed a pragmatic educational classification system that describes the level of modifications required by students with disabilities, rather than one that is driven by their diagnostic label. Few publications have been written about special education in Costa Rica. This is the first historical overview of the...
Field ion microscopical imaging of biomolecules.

specimen molecules are protected from field desorption by embedding them in a platinum matrix, with the use of electrolytic codeposition on tungsten tips. High-resolution helium ion images are obtaind when the biomolecules are exposed during gradual removal of surface layers by controlled field evaporation. Structured images of individual molecules of coenzyme I and vitamin B12are seen.
Role for SUR2A ED Domain in Allosteric Coupling within the KATP Channel Complex

Allosteric regulation of heteromultimeric ATP-sensitive potassium (KATP) channels is unique among protein systems as it implies transmission of ligand-induced structural adaptation at the regulatory SUR subunit, a member of ATP-binding cassette ABCC family, to the distinct pore-forming K+ (Kir6.x) channel module. Cooperative interaction between nucleotide binding domains (NBDs) of SUR is a prerequisite for KATP channel gating, yet pathways of allosteric intersubunit communication remain uncertain. Here, we analyzed the role of the ED domain, a stretch of 15 negatively charged aspartate/glutamate amino acid residues (948–962) of the SUR2A isoform, in the regulation of cardiac KATP channels. Disruption of the ED domain impeded cooperative NBDs interaction and interrupted the regulation of KATP channel complexes by MgADP, potassium channel openers, and sulfonylurea drugs. Thus, the ED domain is a structural component of the allosteric pathway within the KATP channel complex integrating transduction of diverse nucleotide-dependent states in the regulatory SUR subunit to the open/closed states of the K+-conducting channel pore.
Resistance to an optical illusion, figurai after-effects, and field dependence

The ability to resist geometric illusions is shown to be related both to measures of field independence and to figural after-effect potency. Ss who demonstrated figurai after-effects on a particular task, in contrast to those who did not, were able to counteract a presented visual illusion and were also clearly identified as field-independent on a pertinent perceptual task. Consonant with the evidence of previously reported related studies, the present findings continue to show that individual differences in figural after-effect potency are systematically related to a wider gamut of perceptual and behavioral response categories.
A molecular weight revision for compounds of the oligomycin complex.

Abstract Mass spectra and elementary analyses of oligomycins A and B and of several derivatives indicate that their molecular weights and formulas are C 45 H 74 O 11 (M.W. 790) and C 45 H 72 O 12 (M.W. 804), respectively.
Circulating levels of inflammatory markers and mammographic density among postmenopausal women

Mammographic density is strongly associated with breast cancer risk. Inflammation is involved in breast carcinogenesis, perhaps through effects on mammographic density. We evaluated associations between inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) and mammographic density among postmenopausal women. Plasma IL-6, TNF-α, and CRP levels were measured in 145 women with benign breast disease (benign controls) and 397 women with a negative screening mammogram (well controls) enrolled in the Mammograms and Masses Study. Associations between the inflammatory markers and mammographic density were evaluated separately for benign and well controls through correlation analyses and linear regressions. Age-adjusted mean CRP levels were higher among benign controls (2.07 μg/ml) compared to well controls (1.63 μg/ml; P = 0.02), while IL-6 and TNF-α levels were similar between groups. Using linear regression, IL-6, TNF-α, and CRP were not statistically significantly associated with dense breast area within either group. Statistically significant positive associations were observed between all three markers and nondense breast area in both groups; statistically significant negative associations were observed between IL-6 and percent density among benign controls, and between all three markers and percent density among well controls. These associations were all attenuated and non-significant upon adjustment for body mass index. IL-6, TNF-α, and CRP levels were not independently associated with dense breast area, nondense breast area, or percent density in this study population. Our results suggest that these inflammatory factors do not impact breast carcinogenesis through independent effects on mammographic density.
Absentee Ownership and Management in the Black Ghetto: Social and Economic Consequences

The purpose of this paper is to examine the extent of absentee ownership of small businesses in the black ghettoes of three large American cities and to derive quantitative estimates of the impact that absentee ownership and management have on social and economic conditions in such areas. Non-ghetto businesses are compared with ghetto businesses to separate the effects of common business conditions from the fact of location in a particular area. Data are from a survey of 639 small businesses in Chicago, Boston, and Washington, D. C. The findings support the contention of critics that absentee owned or managed businesses dominate the economy of the black ghetto. However, the same conclusion also applies to non-ghetto, low-income white areas. The paper concludes with estimates of the degree to which absentee owned or managed businesses control the flow of important resources in the areas studied.
Special edges, and approximating the smallest directed k-edge connected spanning subgraph

We give two approximation algorithms for finding the smallest k-edge connected spanning subgraph of a digraph. For multidigraphs we achieve performance ratio 2 - 1/3k. This is the first known ratio strictly less than 2. For simple digraphs the best known approximation algorithm is due to Cheriyan and Thurimella. We improve their analysis of the number of "special edges" of a simple digraph. This improves the performance ratio of their algorithm for simple digraphs from 1 + 4/√k to slightly more than 1 + √2/k, for k ≥ 15. Our analysis of the number of special edges is tight for k ≥ 15. For 5
Implicit memory bias in depression

In this review I describe research conducted in my laboratory concerning implicit mood-congruent memory (MCM) bias in clinical depression. MCM is the tendency for depressed individuals to retrieve more unpleasant information from memory than nondepressed controls, and may be an important maintenance mechanism in depression. MCM has been studied frequently with explicit memory tests, but relatively few studies have investigated MCM using implicit memory tests. I describe several implicit memory studies which show that: (a) an implicit MCM bias does not appear to exist when perceptually driven tests are used; (b) implicit memory bias can be found when conceptually driven tests are used, but (c) not all conceptually driven tests show implicit MCM bias. I conclude that conceptual processing is necessary, but is not sufficient for demonstrating implicit memory bias in depression. Future studies should investigate specific components of conceptual elaboration that support implicit memory bias in depression.