cssi/SciSciGPT-SciSciNet huggingface dataset:
Juul and the upsurge of e-cigarette use among college undergraduates

Objective: Examine trends in e-cigarette use, and Juul use specifically, among U.S. college students.Participants: In 2016, we established a cohort of 529 incoming first-year students to a large Midwestern University. In 2018, these students (now third-years) were re-contacted, and a new sample of 611 incoming first-year students was enrolled.Methods: First-year students in 2016 completed a survey assessing their e-cigarette use; in 2018, first- and second-year students reported on e-cigarette use, and use of Juul specifically.Results: From 2016 to 2018, past 30-day e-cigarette use rose from 5.9% to 27.7%. In 2018, for Juul alone, ever use was above 35% and past 30-day use was above 20% for both cohorts. Juul use did not differ by gender, but was associated with higher socioeconomic status (SES) and being White.Conclusions: Findings present disturbing possibilities for long-term nicotine addiction among the next generation, and underscore the need for a rapid public health response.
The epidemic consequences of virulence and free-living survival relationships in models of emerging outbreaks

The relationship between parasite virulence and transmission is a pillar of evolutionary theory that has specific implications for public health. Part of this canon involves the idea that virulence and free-living survival (a key component of transmission) may have different relationships in different host-parasite systems. Most examinations of the evolution of virulence-transmission relationships (theoretical or empirical in nature) tend to focus on the evolution of virulence, with transmission a secondary consideration. In virus evolution, recent studies have examined how the evolution of free-living survival can influence other traits. However, few studies have examined the epidemic-scale consequences of evolution across the different virulence-survival relationships, and specifically, of increased free-living survival. In this study, we utilize a mathematical model motivated by aspects of SARS-CoV-2 natural history to investigate how evolutionary changes in survival traits, and their subsequent relationship to virulence traits, may influence several aspects of disease dynamics. Specifically, we examine how each of two different hypothesized relationships between virulence and survival, one deemed the Curse of the Pharaoh hypothesis and the other more classically referred to as the tradeoff hypothesis. Across virulence-survival frameworks, we found that small changes (5% above and below the nominal value) in survival can have a meaningful effect on certain outbreak features, including the R0, and the size of the infectious peak in the population. These results highlight the importance of properly understanding the relationship between virulence and parasite survival, as they offer considerably different predictions for how the evolution of free-living survival will influence the trajectory of an emerging epidemic.
Shared long-term and short-term memory representational formats in occipital and parietal cortex

Current theories propose that the short-term retention of information in working memory (WM) and the recall of information from long-term memory (LTM) are supported by overlapping neural mechanisms in occipital and parietal cortex. Both are thought to rely on reinstating patterns of sensory activity evoked by the perception of the remembered item. However, the extent of the shared representations between WM and LTM are unclear, and it is unknown how WM and LTM representations may differ across cortical regions. We designed a spatial memory task that allowed us to directly compare the representations of remembered spatial information in WM and LTM. Critically, we carefully matched the precision of behavioral responses in these tasks. We used fMRI and multivariate pattern analyses to examine representations in (1) retinotopic cortex and (2) lateral parietal cortex (LPC) regions previously implicated in LTM. We show that visual memories were represented in a sensory-like code in both tasks across retinotopic regions in occipital and parietal cortex. LPC regions also encoded remembered locations in both WM and LTM, but in a format that differed from the sensory-evoked activity. These results suggest a striking correspondence in the format of WM and LTM representations across occipital and parietal cortex. On the other hand, we show that activity patterns in nearly all parietal regions, but not occipital regions, contained information that could discriminate between WM trials and LTM trials. Our data provide new evidence for theories of memory systems and the representation of mnemonic content.
Sepsis Fluid Metric Compliance and its Impact on Outcomes of Patients with Congestive Heart Failure, End-Stage Renal Disease or Obesity

Abstract Background Emergency physicians express concern administering a 30-cc/kg fluid bolus to septic shock patients with pre-existing congestive heart failure (CHF), end-stage renal disease (ESRD), or obesity, due to the perceived risk of precipitating a fluid overload state. Objective Our aim was to determine whether there is a difference in fluid administration to septic shock patients with these pre-existing conditions in the emergency department (ED). Secondary objectives focused on whether compliance impacts mortality, need for intubation, and length of stay. Methods We conducted a retrospective chart review of 470,558 ED patient encounters at a single urban academic center during a 5-year period. Results Of 847 patients with septic shock, 308 (36.36%) had no pre-existing condition and 199 (23.49%), 17 (2.01%), and 154 (18.18%) had the single pre-existing condition of CHF, ESRD, and obesity, respectively, and 169 (19.95%) had multiple pre-existing conditions. Weight-based fluid compliance was achieved in 460 patients (54.31%). There was a lower likelihood of compliance among patients with CHF (adjusted odds ratio [aOR] 0.35; 95% confidence interval [CI] 0.24–0.52; p Conclusions Septic shock patients with pre-existing CHF, ESRD, or obesity are less likely to achieve compliance with a 30-cc/kg weight-based fluid goal compared with those without these pre-existing conditions.
Necrotizing enterocolitis intestinal barrier function protection by antenatal dexamethasone and surfactant-D in a rat model.

Necrotizing enterocolitis (NEC) is the most common gastrointestinal disorder in premature neonates. Possible therapeutic approaches are centered on promoting maturation of the gastrointestinal mucosal barrier. Studies have demonstrated that antenatal administration of corticosteroids can decrease NEC incidence and mortality. Pregnant rat dams were administered dexamethasone 48 h prior to delivery. The pups were subjected to an experimental NEC-like injury protocol. Ileal tissues and sera were collected and evaluated for inflammatory cytokines, gut permeability and expressions and localizations of tight junction proteins, and surfactant protein-D by immunohistochemistry/immunofluorescent staining. Intestinal epithelial cells (IEC-6) were pretreated with SP-D to examine the effect of SP-D on tight junction protein expressions when challenged with platelet-activating factor and lipopolysaccharide to model proinflammatory insults. Antenatal dexamethasone reduced systemic inflammation, preserved intestinal barrier integrity, and stimulated SP-D expression on the intestinal mucosal surface in pups exposed to NEC-like injury. Pretreatment of SP-D blocked platelet-activating factor/lipopolysaccharide-induced tight junction disruption in IEC-6 cells in vitro. Antenatal dexamethasone preserves the development of intestinal mucosal barrier integrity and reduces incidence and morbidity from an experimental NEC-like injury model. Dexamethasone upregulation of intestinal SP-D-protective effects on tight junction proteins.
Helson, Harry 1898–1977

Harry Helson was an American psychologist and professor of psychology (Bevan in Harry Helson: 1898–1977. Am. J. Psychol. 92(1):153–160, 1979) who is best known for his adaptation-level theory. He was born on November 9, 1898, in Chelsea, Massachusetts in USA and died on October 13, 1977, in Berkeley, USA (Bevan in Harry Helson: 1898–1977 Am. J. Psychol. 92(1):153–160, 1979; Helson, A History of Psychology in Autobiography. Appleton-Century-Crofts, New York, pp. 193–220, 1967). His parents were Jewish immigrants from Eastern Europe. They separated and subsequently he lived with his mother until the age of ten.
Ngugi wa Thiong'o

Chronology 1. Introduction: reading texts and contexts 2. Narrative and nationalist desire: early short stories and The River Between 3. Educating colonial subjects: the 'Emergency' stories and Weep Not, Child 4. Representing decolonization: A Grain of Wheat 5. The poetics of cultural production: Petals of Blood 6. Performance and power: the plays 7. The prisonhouse of culture: Detained and Devil on the Cross 8. The work of art in exile: Matigari 9. Writing freedom: essays and criticism Conclusion.
Digging for gold in the human genome

A large family of human cadherin-like genes shows an unusual genomic organization, suggesting that the nervous system might use DNA rearrangements during development.
Shear Lag Solutions for Sheet-Stringer Panels by Means of a Hydrodynamic Analogy

An analogy is established between the stress flow in flat sheetstringer panels and the plane potential flow of an incompressible fluid. The sheet-stringer panels are presumed to be "shear lag" structures carrying essentially longitudinal loads (parallel to the stringers), and the effects of lateral stresses and deflections are ignored. I t is shown that the hydrodynamic analogy consists of a direct relationship between longitudinal stress and the longitudinally directed component of fluid velocity. Shear stress bears a direct relationship to the laterally directed component of fluid velocit}^. In transferring from the sheet-stringer panel to the equivalent flow, an afnne transformation of coordinates, and, hence, of the panel boundaries, must be made. A discussion is given of the corresponding boundary conditions for the stress flow and the fluid flow. A boundary free of normal stress is equivalent to flow past a solid wall. I t is also shown how rigidly constrained boundaries can be dealt with in re la t ive^ simple fashion. Problems of reinforcement around cutouts in the sheet-stringer panel are also discussed. The use of the analogy is demonstrated in several examples, including the stress concentration around elliptic cutouts, with free and constrained boundaries, in large panels under uniform tension. Also studied is the case of a concentrated longitudinal force applied at the center of a large panel.
9 – HIGH-FREQUENCY VIBRATION SHM WITH PWAS MODAL SENSORS – THE ELECTROMECHANICAL IMPEDANCE METHOD

This chapter will present the use of PWAS transducers as high-frequency modal sensors. The use of PWAS transducers as high-frequency modal sensors has been made possible by the electromechanical (E/M) impedance method, which couples the mechanical impedance of the structural substrate with the electrical impedance measured at the PWAS transducer terminals. In this way, the mechanical resonance spectrum of the structure is reflected in a virtually identical spectrum of peaks and valleys in the real part of the E/M impedance measured at the PWAS terminals. An analytical model is constructed using the constrained PWAS analysis performed in Chapter 9, Section 9.5. The constraining stiffness is actually the dynamic stiffness presented by the structure to the PWAS at the interface. The modal analysis of the structure is performed to calculate the complex-valued frequency-dependent dynamic stiffness as the inverse of the frequency-response function of the structure when excited by the PWAS. The analysis is conducted both in 1-D for linear PWAS transducers attached to beams and in 2-D for circular PWAS transducers attached to circular plates. For complicated structures, the prediction of the E/M impedance spectrum is addressed with the finite-element method (FEM). In a first approach, a conventional FEM analysis is used to calculate the mechanical frequency-dependent dynamic stiffness, which is then inserted in the analytical formulae for the calculation of the E/M impedance of a constrained PWAS. In a second approach, the coupled-field FEM analysis is used to obtain directly the impedance of the PWAS attached to the structure, which is achieved with multi-physics finite elements that have both electrical and mechanical degrees of freedom. The results are compared with analytical results, conventional FEM analysis, and experiments. A number of practical applications of damage detection with the E/M impedance method are also presented.
Perception-Based 2D Shape Modeling by Curvature Shaping

2D curve representations usually take algebraic forms in ways not related to visual perception. This poses great difficulties in connecting curve representation with object recognition where information computed from raw images must be manipulated in a perceptually meaningful way and compared to the representation. In this paper we show that 2D curves can be represented compactly by imposing shaping constraints in curvature space, which can be readily computed directly from input images. The inverse problem of reconstructing a 2D curve from the shaping constraints is solved by a method using curvature shaping, in which the 2D image space is used in conjunction with its curvature space to generate the curve dynamically. The solution allows curve length to be determined and used subsequently for curve modeling using polynomial basis functions. Polynomial basis functions of high orders are shown to be necessary to incorporate perceptual information commonly available at the biological visual front-end.
Pretty in pink: The early development of gender‐stereotyped colour preferences

Parents commonly dress their baby girls in pink and their baby boys in blue. Although there is research showing that children prefer the colour blue to other colours (regardless of gender), there is no evidence that girls actually have a special preference for the colour pink. This is the focus of the current investigation. In a large cross-sectional study, children aged 7 months to 5 years were offered eight pairs of objects and asked to choose one. In every pair, one of the objects was always pink. By the age of 2, girls chose pink objects more often than boys did, and by the age of 2.5, they had a significant preference for the colour pink over other colours. At the same time, boys showed an increasing avoidance of pink. These results thus reveal that sex differences in young children's preference for the colour pink involves both an increasing attraction to pink by young girls and a growing avoidance of pink by boys.
Frame-rate omnidirectional surveillance and tracking of camouflaged and occluded targets

Video surveillance involves watching an area for significant events. Perimeter security generally requires watching areas that afford trespassers reasonable cover and concealment. By definition, such "interesting" areas have limited visibility. Furthermore, targets of interest generally attempt to conceal themselves within the cover sometimes adding camouflage to further reduce their visibility. Such targets are only visible "while in motion". The combined result of limited visibility distance and target visibility severely reduces the usefulness of any panning-based approach. As a result, these situations call for a wide field of view, and are a natural application for omni-directional VSAM (video surveillance and monitoring). This paper describes an omni-directional tracking system. After motivating its use, we discuss some domain application constraints and background on the paracamera. We then go through the basic components of the frame-rate Lehigh Omni-directional Tracking System (LOTS) and describe some of its unique features. In particular, the system's combined performance depends on novel adaptive multi-background modeling and a novel quasi-connected-components technique. These key components are described in some detail, while other components are summarized. We end with a summary of an external evaluation of the system.
Prognostic analysis of invasive circulating tumor cells (iCTCs) in epithelial ovarian cancer.

Abstract Goals Circulating tumor cells (CTCs) have been introduced as a biomarker in detecting advanced epithelial ovarian cancer (EOC). The goals are to examine the prevalence of the invasive subpopulation of CTCs (iCTCs) in patients at high risk of EOC and to compare this biomarker to serum CA125. Methods We used a unique cell adhesion matrix (CAM)-based, functional cell enrichment and identification platform to isolate iCTCs from 129 preoperative patients. We confirmed the identity of iCTCs using positive epithelial (Epi+) markers and negative hematopoietic lineage (HL−) markers. Sensitivity and specificity of the assays were examined and iCTCs/CA125 were correlated with overall survival (OS), progression-free survival (PFS) and clinical parameters. Results We found a 41.2% sensitivity, 95.1% specificity and 77.8% positive predictive value (PPV) of the iCTC assay in detecting patients with stage I and II EOC malignancy, and a 83% sensitivity and 97.3% PPV in detecting all stages of EOC malignancy. However, a positive CA125 test provided weak evidence to detect stage I and II malignancy (61.6% PPV) and all EOC (92.1% PPV), because of its 76.2% specificity. A significantly stronger concordance in OS and PFS of clinical factors (tumor stage, debulking and platinum sensitivity) was noted for elevated iCTCs than for serum CA125. Conclusion The CAM-initiated CTC enrichment/identification method enabled the detection of early stage EOC. iCTCs were better correlated with worse OS and PFS, more specific and better PPV than CA125 in detecting EOC malignancy in patients at high risk of EOC.
Calculations of the energy accommodation coefficient using classical scattering theory

The theory of the energy accommodation coefficient for exchange of energy between a rarefied gas and a clean surface is developed in terms of the differential reflection coefficient for state-to-state scattering of an incoming atomic projectile and a surface. This theory is applied to classical models which have been shown to accurately predict the measured scattered distributions in numerous state-to-state experiments of monoenergetic beams of atoms scattering from clean single crystal surfaces and from clean liquid surfaces. Full three-dimensional calculations are carried out and compared with available experimental data for the accommodation of rare gases at a clean tungsten surface. Good agreement with the experimental measurements is obtained for the heavier mass rare gases where classical theory is expected to be most valid at all measured temperatures.
SiO2/polyacrylonitrile membranes via centrifugal spinning as a separator for Li-ion batteries

Abstract Centrifugal spinning is a fast, cost-effective and safe alternative to the electrospinning technique, which is commonly used for making fiber-based separator membranes. In this work, SiO 2 /polyacrylonitrile (PAN) membranes were produced by using centrifugal spinning and they were characterized by using different electrochemical techniques for use as separators in Li-ion batteries. SiO 2 /PAN membranes exhibited good wettability and high ionic conductivity due to their highly porous fibrous structure. Compared with commercial microporous polyolefin membranes, SiO 2 /PAN membranes had larger liquid electrolyte uptake, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. SiO 2 /PAN membrane separators were assembled into lithium/lithium iron phosphate cells and these cells delivered high capacities and exhibited good cycling performance at room temperature. In addition, cells using SiO 2 /PAN membranes showed superior C-rate performance compared to those using microporous PP membrane.
Optimal Polygon Cover Problems and Applcations

Polygon cover problems arise in computational geometry and in a number of applied areas, such as material layout, layered manufacturing, radiation therapy and radiosurgery, etc. In this paper, we study three optimal polygon cover problems: monotone polygon cover with obstacles, star-shaped polygon cover with obstacles, and rectangular cover. Based on useful geometric observations, we develop efficient algorithms for solving these problems. Either our algorithms improve the quality of the previously best known solutions for these polygon cover problems, or our complexity bounds are comparable to those of the previously best known algorithms for simpler cases of the problems.
A study of conflict between shopping center managers and retailers within regional shopping centers

This article reports on a study of conflict between center managers and retail tenants in regional shopping centers in Ohio. Also, issues important to the successful operation of a regional center are identified. The results show that conflict does exist, and the differences in conflict perceived by center managers and tenants are significant. Specific areas of disagreements are pinpointed. The results show that the extent of conflict that exists is a function of the size of the shopping center and the proportion of the total square footage of gross leasable area occupied by major tenants.
Blood changes in Bufo cognatus following acute heat stress.

Abstract 1. 1. Various blood constituents were measured in an attempt to identify the effects of exposure of Great Plains toads to the critical thermal maximum (CTmax) and determine the time course of the onset of and recovery from these effects. 2. 2. Tests for generalized tissue damage inclucling serum glutamic-oxalacetic and glutamic-pyruvic transaminases (SGOT, SGPT), total protein and blood urea nitrogen (BUN) were unaffected by acute thermal stress. 3. 3. Hematocrit, erythrocyte number, mean cell volume and hemoglobin concentration were also unchanged. 4. 4. Blood glucose, lactic acid and creatine phosphokinase (CPK) levels all increased significantly. 5. 5. Blood pH, P O 2 and HCO 3 − also increased with acute heat stress while P CO 2 decreased. 6. 6. Long-term exposure to temperatures near the CTmax may cause severe tissue damage. Acute thermal stress does not appear to cause damage other than the short-term, reversible effects of strong physical exercise.
Ion velocity distribution measurements in a magnetized laser plasma expansion

Langmuir probes are used to study the expansion of a laser plasma into a large (17 m long × 0.6 m diameter) ambient magnetized cylindrical plasma. The expansion is either perpendic- ular or at 45 ◦ to the 300 − 600 G axial background field. One probe geometry allows data c ollection close to the ablation surface, inside a diamagnetic bubble f ormed during the laser plasma expan- sion. We measure expansion velocities of this diamagnetic cavity and the bulk laser plasma. Ad- ditionally, we detect fast ions along the axis of the ambient plasma column when the laser plasma expansion is directed at 45 ◦ to the background field. We obtain the fast ion velocity distr ibution by comparing the measured ion gyroradii to those predicted by Monte Carlo simulations of the ion trajectories in an external magnetic field. Experimental me asurement of fast ion velocity distribu- tions can help tune the experimental parameters that are required to drive collisionless shock waves through a laboratory plasma.
Efficient parallel linear programming

Linear programming and least squares computations are accelerated using author's parallel algorithms for solving linear systems. The implications on the performance of the Karmarkar and the simplex algorithms for dense and sparse linear programs are examined. The results have further applications to combinatorial algorithms.
Effect of physical aging on nucleation of amorphous indomethacin.

Differential scanning calorimetry has been used to study glassy indomethacin aged at 0 and −10 °C for periods of time up to 109 and 210 days, respectively. The results demonstrate the emergence of a small melting peak of the α-polymorph after aging for 69 days at 0 °C and for 147 days at −10 °C (i.e., ∼55 °C below the glass-transition temperature) that provides evidence of nucleation occurring in the temperature region of the β-relaxation. The evolution of an endothermic recovery peak temperature features a plateau at longer annealing times that suggests that the glass has made significant progress toward reaching the supercooled liquid state. It has been found that the melting peaks become detectable after the recovery peak has reached the plateau. The results highlight the importance of studying physical aging in the temperature region of the β-relaxation as a means of evaluating the physical stability of amorphous pharmaceutical materials.
Watkins offers view of future DOE mission

The fifth plenary meeting of the Secretary of Energy Advisory Board (SEAB) was held in Washington on July 10. Opening comments by Admiral James Watkins, Secretary of the Department of Energy, provided insights into his vision of the agency's future direction. These are exciting times, Watkins said, declaring that the “evil empire has disappeared.” He hailed Boris Yeltsin's recent declaration to Congress that communism is dead. Watkins spoke of the opportunities of the “new world order,” but also said that DOE is facing a management challenge of great proportions.
Human monocytes selectively bind to cells expressing the tumorigenic phenotype

The characteristics of the binding of human monocytes to tumor cells were studied by a newly developed microassay. First, we determined the kinetics and optimal conditions of the binding. Monocytes recognized and bound to tumor cells very rapidly within 10–20 min of cellular interaction. Binding was also more efficient at 37°C suggesting that active metabolism of monocytes is required. Second, we determined that selective binding of monocytes to cells with tumorigenic phenotypes occurs. For this purpose, lymphocytic leukemia cell lines versus normal lymphocytes, and tumorigenic versus nontumorigenic hybrids from the same parental lines were compared as the targets of the binding assay. In both cases, neoplastic cells were selectively bound by monocytes. Although tumor cells were bound rapidly and selectively by monocytes, initial recognition and binding did not necessarily lead to subsequent tumor cell lysis. This is based on the observation that some tumorigenic parental and hybrid lines were avidly bound by monocytes yet not subsequently killed in a cytotoxicity assay.
Strain effects on n-InGaAs heterostructure-on-insulator made by direct wafer bonding

Abstract We have investigated the strain effects on the effective channel mobility of InGaAs pseudo (Ψ) n-MOSFETs by means of mechanical beam bending technique. For this goal, III–V heterostructures were grown on InP and transferred onto Si by direct wafer bonding. We show that an increase in electron mobility of up to 70% can be achieved under tensile strain. Simulations of InGaAs band-structure parameters under strain suggest that in the present case mobility enhancement is due to an increase of the sheet carrier density rather than to a decrease of the effective mass.
Laboratory P- and S-wave measurements of a reconstituted muddy sediment with comparison to card-house theory.

Laboratory measurements of acoustic wave propagation in a reconstituted kaolinite-based mud were performed. Pairs of ultrasonic transducers and bender elements were immersed in the sediment to transmit and receive compressional and shear waves, respectively. Estimates of wave speeds and attenuations were acquired by analyzing waveforms recorded at several transmitter/receiver separation distances. Measured wave speeds were in good agreement with predicted values from the Mallock-Wood equation for compressional wave speed and card-house theory for shear wave speed. To the knowledge of the authors, no comparison exists between shear wave speeds measured in a controlled laboratory setting and the card-house theory. Power law fits were obtained from the attenuation data to determine the frequency dependence, with f0.73 for compressional waves in the 60 to 110 kHz range and f1.46 for shear waves in the 100 to 400 Hz range.
Parallel Methods for ODEs with Improved Absolute Stability Boundaries

A number of variations of block predictor-corrector methods have been proposed for the parallel solution of ordinary differential equations, but they have usually been viewed as deficient because of their relatively small stability intervals. This paper proposes a simple idea for extending the stability intervals: with the use of suitable linear combinations of the predicted and corrected values, the stability intervals can be expanded considerably. Several existing methods are modified in this manner. The resulting new methods and the existing methods are compared using a collection of standard test problems.
Understanding the Dynamics of the Victim-Perpetrator Relationship in Child Sexual Abuse: an Examination of the Child Sex Abuse Victimization Data in South Korea

The objective of this study is to examine the dynamics of the victim-perpetrator relationship in cases of child sex abuse to develop effective crime prevention measures. The paper first reviews child sexual abuse in an Asian culture, general characteristics of the victim and the perpetrator, reporting behavior, and crime prevention for child sexual abuse. Following, this is a discussion about the data source and its findings. In total, 92 sexually abused children (age 13 or under) participated in medical forensic interviews and psychological evaluations prior to receiving proper medical and/or psychological treatment at a regional victim assistance center for child sexual abuse located in Daegu, South Korea. The findings of the study support the assumptions of a correlation regarding the social environmental characteristics of the victim’s family, the victim-perpetrator relationship, and the sexual abuse. Moreover, some of the findings are quite unique with respect to previous research. For example, about 20 % of the assaults occurred among similar age groups, such as friends and sibling. Additionally, mothers and schoolteachers first recognized almost 80 % of the sexual assaults. Finally, the paper discusses the implications for social environmental crime prevention policy based on these findings.
Gap junctional intercellular communication of bovine luteal cells from several stages of the estrous cycle: Effects of prostaglandin F2α, protein kinase C and calcium

Abstract Cellular interactions mediated by both contact-dependent and contact-independent mechanisms are probably important to maintain luteal function. The present studies were performed to evaluate the effects of luteotropic and luteolytic hormones, and also intracellular regulators, on contact-dependent gap junctional intercellular communication (GJIC) of bovine luteal cells from several stages of luteal development. Bovine corpora lutea (CL) from the early, mid and late luteal phases of the estrous cycle were dispersed with collagenase and incubated with no treatment, LH, PGF or LH + PGF (Experiment 1), or with no treatment, or agonists or antagonists of protein kinase C (TPA or H-7) or calcium (A23187 or EGTA; Experiment 2). After incubation, media were collected for determination of progesterone concentrations. Then the rate of GJIC was evaluated for small luteal cells in contact with small luteal cells, and large luteal cells in contact with small luteal cells by using the fluorescence recovery after photobleaching technique and laser cytometry. Luteal cells from each stage of the estrous cycle exhibited GJIC, but the rate of GJIC was least (P
A variable structure model following control design for robotics applications

A variable structure model following control (VSMFC) design method is proposed for robotics applications. The method allows the designer to model the nonlinear dynamic interactions among the different mechanical components of the robot system even when an adaptive control solution is called for to satisfy stringent performance requirements. A VSMFC design for a planar two-link robot arm is considered as an example. >
Normal probability plots and the estimation of distribution tails

Abstract Quantiles used in normal probability plots can be estimated more accurately from the maximum entropy ( ME ) distribution than from the order statistics of the sample distribution. The symmetric ME distribution yields additional improvements.
Requirements determination for common systems: turning a global vision into a local reality

Abstract A ‘common’ information system is one that is intended to satisfy the needs of multiple user groups within a firm for a particular functionality (e.g. one order entry system to be used by all divisions of a global firm). Such systems are often comprised of both core (or common) software modules, as well as local modules to support regional requirements. One of the most significant challenges for any information systems (IS) project is determining information requirements. The requirements determination process is especially difficult in this context in which common, global requirements must be forged from disparate, and potentially conflicting, local needs and priorities. This paper reports on case studies of two projects undertaken to globally deploy common systems, and it develops a model of the requirements determination process. The proposed model posits stakeholders engage in knowledge acquisition and negotiation processes in order to determine global requirements as well as to foster consensus and buy-in, on the part of the local regional stakeholders, to the global system. The findings also suggest that knowledge acquisition is a relatively structured, rational approach to learning about local needs and requirements, where stakeholders share an awareness of the corporate vision for global standards and agree on the need for a new system. Negotiation, in contrast, is less structured and more political, with different parties lobbying for their own interests as they endeavor to identify common requirements for the new global system. Finally, the results suggest that the requirements determination process is influenced by an articulated corporate vision for a global system, needs and priorities of the local regions, and the organizational roles and skills of key stakeholders. Implications of the results are drawn and suggestions for future research are offered.
Cancer Chemoprotection by Oltipraz: Experimental and Clinical Considerations

Oltipraz (4-methyl-5-(2-pyrazinyl)-1,2-dithiole-3-thione) is an antischistosomal drug presently under evaluation as a possible chemoprotective agent in humans. To date, oltipraz has proved effective as an inhibitor of carcinogenesis in experimental models for breast, bladder, liver, forestomach, colon, tracheal, lung, and skin cancer. Studies on the mechanisms of action of oltipraz indicate that it affects the metabolism and disposition of chemical carcinogens, principally through the induction of electrophile detoxication enzymes. While this feature is common to many different classes of both natural and synthetic experimental chemoprotectors (i.e., phenolic antioxidants, isothiocyanates, flavonoids, indoles, cinnamates, coumarins, terpenes, and others), oltipraz may offer the earliest and easiest prospect for examining the role of enzyme induction as a protective strategy in humans. Unlike the situation with many of the anutrients, substantial preclinical research has already been conducted with oltipraz to establish its safety and efficacy in animals. Hopefully, Phase I investigations will demonstrate a high tolerance for oltipraz in the chemoprotective dose range of the drug. A major concern for the success of any trial is selecting participants who are likely to adhere to the intervention as well as to all aspects of the protocol. Factors influencing participation and adherence in a trial include the design of the trial, the nature of the disease under study as well as the nature of the intervention, in particular the toxicities of the intervention (J. A. Tangrea, M. E. Adrianza, and W. E. Helsel, Cancer Epi Biomarkers Prev 1992; 1:325-330). Chemoprotection trials with oltipraz have an excellent prospect for success. Individuals with known carcinogenic exposures are likely to be interested in participation in trials designed to reduce the risks of the exposures. Moreover, the availability of intermediate markers reflecting the modulation of the biologically effective dose of environmental carcinogens as study end points will enable efficient trials to be designed.
Demonstration of the Role of Scission of the Proximal Histidine−Iron Bond in the Activation of Soluble Guanylyl Cyclase through Metalloporphyrin Substitution Studies§

Activation of soluble guanylyl cyclase (sGC) by NO correlates with scission of the proximal iron−histidine bond, as demonstrated by the application of electronic absorption and resonance Raman spectroscopy to the study of metalloporphyrin-substituted enzymes. The non-native metalloporphyrins, Mn(II)PPIX and Co(II)PPIX, can be introduced into heme-deficient sGC forming five-coordinate complexes. The similarity among Mn(II)sGC, Co(II)sGC, and the corresponding metalloporphyrin-substituted derivatives of Mb and Hb provides confirming evidence for the presence of an axial histidine ligand in sGC. Upon addition of NO, Mn(II)sGC forms a six-coordinate species with the histidine ligand still bound to the Mn, and the enzyme is not activated. In contrast, the Co(II)sGC(NO) adduct is five-coordinate and the enzyme is activated. These data imply that the activated state of sGC is attained when the proximal histidine−metal bond is broken.
Cavernous hemangioma of the orbital apex: pathogenetic considerations in surgical management.

Purpose To consider the pathogenesis and growth of cavernous hemangioma, particularly within the crowded orbital apex, in decisions regarding surgical indications, timing, and technique. Design A perspective based on analysis of the microanatomic relationships and growth potential of apical cavernous hemangiomas, with representative case studies illustrating management recommendations. Methods Analysis of microscopic findings in typical and vision-loss cases; review of tumor growth patterns as reported in observational and interventional studies; consideration of surgical approaches and reported functional outcomes. Results An ongoing, local hemodynamic imbalance may drive the proliferation of a cavernous hemangioma. Extension into neighboring tissue induces a fibrous capsule, which is continually reconstituted as the lesion expands, and which may incorporate visually critical structures in the confines of the apex. The extent of this microanatomic intimacy is not detectable preoperatively. The tumor's remaining growth potential at the time of diagnosis or following incomplete resection is not predictable. Conclusions Patients without significant vision deficits should be observed for progression. Those with significant deficits or signs of progression should be offered timely surgery, with recognition of the risks. The surgical approach should be individualized based on macroanatomic relationships. The decision to intervene should not be a commitment to complete resection at any cost; intraoperative recognition of “inoperable” attachments may dictate modifications in order to preserve vision.
The growth hormone-insulin like growth factor axis revisited: lessons from IGF-1 and IGF-1 receptor gene targeting

We have created a liver-specific igf1 gene-deletion mouse model (LID) with markedly reduced circulating IGF-I levels. They demonstrate that while they have normal growth and development they develop insulin resistance secondary to the elevation of circulating growth hormone. When mated with an acid-labile subunit (ALS) gene-deleted mouse they also show osteopenia suggesting that circulating IGF-I levels play a significant role in bone formation. In a separate transgenic mouse we created a model of severe insulin resistance and type 2 diabetes by the overexpression of a dominant-negative IGF-I receptor in skeletal muscle. In this model we show that lipotoxicity plays a major role in the progression of the disease and is affected by treatment with a fibrate, which reverses the insulin resistance and diabetic state. These models are therefore very useful in studying human physiology and disease states.
Spanning subsets of toroidal and Klein bottle embeddings

Abstract We study the spanning subsets of toroidal and Klein bottle embeddings, such as spanning disks, spanning cylinders and spanning Mobius bands.
The measurement of fiber strength parameters in fragmentation tests by using acoustic emission

The Weibull shape and scale strength parameters of E-glass fibers were measured in situ by counting the number of acoustic emission events (fractures) during the fragmentation of single-fiber E-glass/epoxy composites. A median subtraction filter provided a trigger signal sensitive to emission events but not to noise. Values obtained for the strength parameters are comparable to those obtained with optical microscopy. And, although there is considerable scatter, acoustic emission energy measurements tend to suggest that the recovery length is approximately constant at low stresses. Advantages of using acoustic emission are discussed.
Flash and distillation calculations by a Newton-Like method

Abstract A hybrid approach, one based on the combined use of Newton's method and the Schubert update, is applied to flash and distillation problems. the main advantages of this approach are two-fold. First, it makes maximum use of readily available analytical first partial derivative information. Second, it approximates those derivatives which are both difficult and expensive to obtain, primarily K value and excess enthalpy-composition derivatives, cheaply yet accurately by using a quasi-Newton formula. This hybrid (or Newton-like) approach is compared to a partial Newton method (i.e. one that neglects those difficult and/or expensive derivatives), Schubert's method and a finite difference implementation of Newton's method. In short, our hybrid approach compares favorably with a finite difference Newton method and is usually both more efficient and more robust than either the partial Newton or Schubert method on these problems. In fact, it generally requires only a few more iterations than Newton's method to reach the desired accuracy. However, it usually uses between 60 and 70% fewer rigorous physical properties calculations than Newton's method. This, in our opinion, is important because rigorous physical properties calculations usuallly constitute the largest portion of the calculations (and therefore cost) associated with separation problems. Several examples are presented to support these claims.
A Theory of Wage and Promotion Dynamics Inside Firms

We show that a framework that integrates job assignment, human-capital acquisition, and learning captures several empirical findings concerning wage and promotion dynamics inside firms, including the following. First, real-wage decreases are not rare but demotions are. Second, wage increases are serially correlated. Third, promotions are associated with large wage increases. Fourth, wage increases at promotion are small relative to the difference between average wages across levels of the job ladder. Fifth, workers who receive large wage increases early in their stay at one level of the job ladder are promoted quickly to the next.
Phylloquinone intake as a marker for coronary heart disease risk but not stroke in women

Objective: To examine the feasibility of using phylloquinone intake as a marker for coronary heart disease (CHD) and stroke risk in women. Design and setting: Nurses' Health Study, a prospective cohort study during 1984–2000. Dietary data were collected in 1984, 1986, 1990, and 1994 using a validated semiquantitative food frequency questionnaire. Subjects: A total of 72 874 female nurses, aged 38–65 y, without previously diagnosed angina, myocardial infarction (MI), stroke, or cancer at baseline. Main outcome measures: Incidence of nonfatal MI, CHD deaths, total CHD events, ischemic, and total strokes. Results: There were 1679 CHD events (1201 nonfatal) and 1009 strokes (567 ischemic). After adjustment for age and lifestyle factors associated with cardiovascular disease risk, the multivariate relative risks (RR) (95% CI) of total CHD from the lowest to the highest quintile category of phylloquinone intake were 1 (reference), 0.80 (0.69–0.94), 0.86 (0.74–1.00), 0.77 (0.66–0.99), and 0.79 (0.68–0.92), P for trend=0.01. Further adjustment for dietary intakes of saturated fat, polyunsaturated fat, trans fatty acids, eicosapentaenoic, and docosahexaenoic acids, cereal fiber, and folate attenuated the association (RR comparing extreme quintiles 0.84 [0.71–1.00], P for trend=0.12). Incidence rates of total or ischemic strokes were not associated with phylloquinone intake. Conclusion: The data suggest that high phylloquinone intake may be a marker for low CHD risk. Dietary and lifestyle patterns associated with phylloquinone intakes, rather than intake of the nutrient itself, might account for all or part of the weak association. Sponsorship: US Department of Agriculture, National Institute of Health and Academy of Finland.
Quasiharmonic shifts in heats of adsorption of helium adatoms on graphite

Abstract Calculations are presented of the change in the heat of adsorption of helium atoms adsorbed on the basal plane of a graphite surface due to quantum effects. The effect of including quantum corrections in the zero-point energy of the adatom in the direction normal to the surface is studied in the limit of low coverage where lateral interactions with other adatoms may be neglected. Quantum corrections to the zero-point energy and pressure are treated using the Zucker approximation taken from the theory of the ideal inert gas solids. The interactions between the adatom and the graphite lattice are treated by the use of a central Mie-Lennard-Jones 6–12 potential with the potential parameters obtained by a number of different energy-combination rules in current use. It is found that the inclusion of zero-point quantum corrections shifts the equilibrium spacing of the adatom relative to the surface graphite plane outward by a few percent, leading in the case of He adatoms to a sizable change in the heat of adsorption. It is also shown that the trends in the lattice spacing shift and heat of adsorption shift are preserved for all of the energy-combination rules in current use. Suggestions concerning the experimental measurement of the shifts discussed herein are suggested, based upon the measurement of the gas surface second virial coefficient and through the analysis of isotopic adsorption isotherm data at low coverage.
Acoustic waves in slender axisymmetric tubes

Acoustic waves in a rigid axisymmetric tube with a variable cross-section are considered. The governing Helmholtz equation is solved using Neumann series (expansions in Bessel functions of various orders) with a stretched radial coordinate, leading to a hierarchy of one-dimensional ordinary differential equations in the longitudinal direction. The lowest approximation for axisymmetric motion includes Webster's horn equation as a special case. Fourth-order differential equations are obtained at the next level of approximation. Good agreement with existing asymptotic theories for waves in slender tubes is found.