cssi/SciSciGPT-SciSciNet huggingface dataset:
Desensitization of IL-4 secretion from mouse bone marrow-derived mast cells

Several recent findings indicate that mouse bone marrow-derived mast cells (BMMC) express RNA encoding interleukin-4 (IL-4) and secrete detectable amounts of IL-4 in response to cross-linking of Fc epsilon RI receptors, Fc gamma R receptors, or to ionomycin. We investigated the desensitization of BMMC from the view point of both IL-4 secretion and histamine release. In a desensitization protocol, the cells were challenged with an optimal concentration of antigen (10 ng/ml of DNP33-BSA) in the absence of calcium for various periods of time followed by addition of calcium to determine the loss in ability to release histamine or IL-4. In the context of histamine release, BMMC were desensitized completely in 45 min (T1/2 approximately 5 min). By contrast, in the context of IL-4 secretion, BMMC were only partly desensitized (52 +/- 5% of the control response) after 1 h of desensitization. A longer-term (2-6 h) desensitization of BMMC did not result in complete inhibition of IL-4 secretion (44 +/- 5% of control after 6 h). Northern blot analysis showed that IL-4 mRNA accumulation was decreased after a 1 h desensitization (37% +/- 14% of non-desensitized cells), suggesting that desensitization of IL-4 release results from a decrease in the amount of mRNA accumulation. These and other data support the view that the IgE-mediated signal transduction cascade has meditor-specific pathways that are independently regulated by homeostatic mechanisms within mast cells.
The institutional origins of American literary history

This article deals with the importance of institutions in the construction of literary classifications. Following Mary Douglas, the article offers a double-stranded perspective on institutions that stresses both their social and cognitive anchorage. This is applied to one particular case, namely the genealogy connecting Emerson (and the Transcendentalists) to Jonathan Edwards. The article shows how Perry Miller's 'discovery' of that lineage in 1940 has an institutional history that goes as far back as the early beginnings of American literature as an academic discipline. Part of the function of the discipline, the article argues, is to hide this history in order to bring out the continuing relevance of such taxonomies. The concluding paragraph identifies some implications of this view on institutionalization for current discussions about the (post-) nationality of American literature.
Perioperative cardiac assessment for noncardiac surgery: eight steps to the best possible outcome.

The prevalence of cardiovascular disease in the United States1 and the number of noncardiac surgical procedures performed are progressively increasing. Preoperative risk assessment is an important step in reducing perioperative morbidity and mortality in patients undergoing noncardiac surgery. Successful perioperative evaluation is best achieved by combining an integrated multidisciplinary approach with good communication between the patient, primary care physician, anesthesiologist, consultant, and surgeon. The goal of appropriate preoperative evaluation and therapy should be to not only improve immediate periprocedural outcomes but also to improve long term clinical outcome. ### Case A 68-year-old man with diabetes, hyperlipidemia, and lifestyle-limiting claudication requires aorto-bifemoral bypass surgery. He has a history of prior myocardial infarction 6 years ago and has had infrequent episodes of angina since then. His ability to perform physical activity is limited by claudication. He is currently taking aspirin, long-acting nitrates, glyburide, and lovastatin. Does he need further evaluation before his elective surgery? What can be done to minimize his risk of perioperative complications? #### (1) Assess the Patient’s Clinical Features The history and physical examination should emphasize identification of markers of cardiac risk and assess the patient’s cardiac status. High-risk cardiac conditions include recent myocardial infarction (MI), decompensated heart failure (HF), unstable angina, symptomatic arrhythmias, and symptomatic valvular heart disease. The patient’s underlying cardiac conditions, although apparently stable at present, may become manifest during perioperative stresses. Such conditions include stable angina, distant MI, prior HF, or moderate valvular disease. One should also identify serious comorbid conditions such as diabetes, stroke, renal insufficiency, and pulmonary disease because these illnesses may also affect periprocedural outcomes. Table 1 lists the factors that increase the risk of perioperative cardiac complications in patients undergoing noncardiac surgery.2 View this table: TABLE 1. Factors That Increase the Risk of Perioperative Cardiac Complications and Indications for Perioperative β-Blocker Therapy #### (2) Evaluate Functional Status The history should assess functional capacity (the ability to …
A dynamic test of the marginality hypothesis

The marginality hypothesis is an attempt to relate the voting margins of members of Congress to their subsequent legislative behavior. A major corollary of the hypothesis is that members of Congress with small victory margins will be more responsive to constituents than those with large victory margins. This has been assumed to mean that electorally secure representatives can afford to be more loyal to their congressional parties, since they have less cause to worry about their chances for reelection. Previous empirical studies have produced mixed results. We ask the question in a different way: Do changes in marginality affect party voting within Congress? If so, major shifts in the electorate potentially can have a fundamental impact on the behavior of Congress itself. We find that this is not true. Electoral margin is simply not related to party loyalty.
Ultrasound guidance for distal insertion of ventriculo-atrial shunt catheters: technical note

Ventriculo-atrial (VA) shunts are often used for CSF diversion in situations involving abdominal pathology that preclude the use of ventriculo-peritoneal shunts. Distal (venous) catheters of VA shunts have historically been inserted using a cut-down on the internal jugular vein (IJV). Less invasive placement of atrial catheters may minimize operative times and attenuate post-operative incisional discomfort. We describe a method for atrial catheter placement using ultrasound guidance to visualize the IJV and facilitate percutaneous venous puncture in 17 adult patients (23 total insertions) undergoing treatment for hydrocephalus or pseudotumor cerebri. The IJV and carotid artery were visualized by ultrasound in 23 (100%) cases. Venous penetration and successful atrial catheter placement was achieved on the first attempt in 23 (100%) cases. Pneumothorax, carotid artery puncture or need for venous cut-down occurred in no cases. The utilization of ultrasound guidance for distal VA shunt catheter insertion may increase comfort with this procedure and ultimately decrease complication rate and operative time.
Functional characterization of soluble and membrane-bound forms of vaccinia virus complement control protein (VCP)

Vaccinia virus secretes a 35 kD protein, vaccinia virus complement control protein (VCP), that inhibits the classical and alternative pathways of complement at several points, indicating that it may be a viral analogue of human complement receptor type 1 (CR1; CD35). Structurally, however, CR1 is composed of 30 short consensus repeats (SCRs), whereas VCP consists entirely of four SCRs. We have begun a structure–function analysis of VCP to define the minimum number of SCRs necessary for function, the functional differences between VCP and CR1, and the potential therapeutic roles for VCP. We addressed these questions by creating and characterizing recombinant soluble and membrane-bound forms of VCP. We have determined that (1) VCP requires all four SCRs to bind C3b, (2) whereas CR1 binds C3b and iC3b, VCP binds C3b but not iC3b, and (3) although normally secreted, if expressed on the membrane of mammalian cells, VCP effectively protects the cells from complement-mediated lysis. Thus, VCP appears to be a compact and unique complement regulatory protein with the ability to inhibit both arms of the complement cascade, but lacking affinity for iC3b. By releasing rather than capturing iC3b-bearing complexes following inactivation of C3b, VCP may ‘recycle’ its active site locally among infected cells, and thereby enable the virus to evade more efficiently host immune and inflammatory responses. The unique function, compact structure, and capacity of VCP to protect mammalian cells from complement-mediated attack, suggests that it could be used both to better understand the structure–function relationship of complement regulatory proteins, in general, and also to rationally design and develop novel therapeutic agents.
Temporal dynamics of changes in reactive oxygen species (ROS) levels and cellular morphology are coordinated during complementary chromatic acclimation in Fremyella diplosiphon

Fremyella diplosiphon alters the phycobiliprotein composition of its light-harvesting complexes, i.e., phycobilisomes, and its cellular morphology in response to changes in the prevalent wavelengths of light in the external environment in a phenomenon known as complementary chromatic acclimation (CCA). The organism primarily responds to red light (RL) and green light (GL) during CCA to maximize light absorption for supporting optimal photosynthetic efficiency. Recently, we found that RL-characteristic spherical cell morphology is associated with higher levels of reactive oxygen species (ROS) compared to growth under GL where lower ROS levels and rectangular cell shape are observed. The RL-dependent association of increased ROS levels with cellular morphology was demonstrated by treating cells with a ROS-scavenging antioxidant which resulted in the observation of GL-characteristic rectangular morphology under RL. To gain additional insights into the involvement of ROS in impacting cellular morphology changes during CCA, we conducted experiments to study the temporal dynamics of changes in ROS levels and cellular morphology during transition to growth under RL or GL. Alterations in ROS levels and cell morphology were found to be correlated with each other at early stages of acclimation of low white light-grown cells to growth under high RL or cells transitioned between growth in RL and GL. These results provide further general evidence that significant RL-dependent increases in ROS levels are temporally correlated with changes in morphology toward spherical. Future studies will explore the light-dependent mechanisms by which ROS levels may be regulated and the direct impacts of ROS on the observed morphology changes.
Modeling the thermal properties and the gas flux from a porous, ice-dust body in the orbit of P/Wirtanen

Abstract Sublimation of gases from ices in porous bodies is an important, observable phenomenon in the solar system. Dust mantle build-up and surface erosion on a comet nucleus and coma formation are processes related to the flux of sublimating gases. Computer simulations are performed to model the gas flux from volatile, icy components in the surface layer of a porous, Jupiter-family model comet assuming a porous body, containing dust and up to four components of chemically different ices (e.g. H2O, CO, CO2, CH4). The mass and energy equations are solved for the different volatiles simultaneously. Inflowing and outflowing gas within the body, dust mantle build-up, depletion of the most volatile ices in outer layers, and recondensation of gases in deeper layers are included in the model. The calculations start with a homogeneously mixed body at a constant temperature and a constant mass density at aphelion of an orbit. The internal heat of the body increases due to insolation and conduction. As a result of sublimation of the minor, more volatile components, the initially homogeneous body differentiates into a layered body. The depths of the boundaries between the layers (sublimation fromts of the corresponding volatile phases) change with time and are on the order of tens of meters. Temperature, porosity, relative chemical abundance, and pore size distributions are obtained as a function of depth, and the gas flux into the interior and into the coma for each of the volatiles at various positions of the comet in its orbit. The ratio of the gas flux of minor volatiles to that of H2O in the coma varies by several orders of magnitude throughout the orbit and cannot be simply related to the mixing ratio of the ices in the body. It is believed that the mixing ratio of the minor constituents of frozen gases in the ice-dust conglomerate of the nucleus is a very important clue to the original composition of the frozen gases in the solar nebula, but it is not well understood. To address this important issue, the present coma chemistry model is combined with the nucleus surface layers model for a more physically realistic gas production rate from which to begin the coma calculations. The combined model incorporates gas production into the coma from three sources: volatile sublimation at the nucleus surface, subsurface sublimation of volatiles from the interior, and release of gas from the dust grains in the coma (distributed sources).
Development of a semi-automatic alignment tool for accelerated localization of the prostate

Abstract Purpose: Delivering high dose to prostate with external beam radiation has been shown to improve local tumor control. However, it has to be carefully performed to avoid partial target miss and delivering excessive dose to surrounding normal tissues. One way to achieve safe dose escalation is to precisely localize prostate immediately before daily treatment. Therefore, the radiation can be accurately delivered to the target. Once the prostate position is determined with high confidence, planning target volume (PTV) safety margin might be reduced for further reduction of rectal toxicity. A rapid computed tomography (CT)-based online prostate localization method is presented for this purpose. Methods and Materials: Immediately before each treatment session, the patient is immobilized and undergoes a CT scan in the treatment position using a CT scanner situated in the treatment room. At the CT console, posterior, anterior, left, and right extents of the prostate are manually identified on each axial slice. The translational prostate displacements relative to the planned position are estimated by simultaneously fitting these identified extents from this CT scan to a template created from the finely sliced planning CT scan. A total of 106 serial CT scans from 8 prostate cancer patients were performed immediately before treatments and used to retrospectively evaluate the precision of this daily prostate targeting method. The three-dimensional displacement of the prostate with respect to its planned position was estimated. Results: Five axial slices from each treatment CT scan were sufficient to produce a reliable correction when compared with prostate center of gravity (CoG) displacements calculated from physician-drawn contours. The differences (mean ± SD) between these two correction schemes in the right-left (R/L), posterior-anterior (P/A), and superior-inferior (S/I) directions are 0.0 ± 0.4 mm, 0.0 ± 0.7 mm, and −0.4 ± 1.9 mm, respectively. With daily CT extent-fitting correction, 97% of the scans showed that the entire posterior prostate gland was covered by PTV given a margin of 6 mm at the rectum-prostate interface and 10 mm elsewhere. In comparison, only 74% and 65% could be achieved by the corrections based on daily and weekly bony matching on portal images, respectively. Conclusions: Results show that daily CT extent fitting provides a precise correction of prostate position in terms of CoG. Identifying prostate extents on five axial CT slices at the CT console is less time-consuming compared with daily contouring of the prostate on many slices. Taking advantage of the prostate curvature in the longitudinal direction, this method also eliminates the necessity of identifying prostate base and apex. Therefore, it is clinically feasible and should provide an accelerated localization of the prostate immediately before daily treatment.
Quantum dynamics in nonequilibrium strongly correlated environments

We consider a biased quantum point contact between two Luttinger liquids measuring a quantum-mechanical system (oscillator). There are three main physical results. First, we find that for voltages higher than the oscillator level spacing, the effect of the measurement is equivalent to coupling to a heat bath, with an effective temperature that only depends on the device $I\ensuremath{-}V$ characteristic. Second, we find that this heating changes the $I\ensuremath{-}V$ characteristics on the junction. Finally, we predict a modulation of the tunneling current at the oscillator frequency. Also, we find that a generalized nonequilibrium fluctuation-dissipation relation connects the decoherence and dissipation of the oscillator to the current-voltage characteristics of the device.
Polyoxometalates in Catalytic Selective Homogeneous Oxygenation and Anti-HIV Chemotherapy

This review concentrates on two areas of intense research interest involving polyoxometalates, homogeneous catalysis and medicine. The discussion of homogeneous catalysis covers a brief historical overview of organic substrate oxidation, oxidant desirability, and other classes of oxidation catalysts. The principal focus of the catalysis, use of oxidatively resistant d-electron-transition-metal-substituted polyoxometalates (TMSP) for sustained oxygenation of organic substrates, is then examined. A general compilation is given in Table I of the literature reactions involving 21 TMSP complexes, 10 oxidants, five classes of substrates, and 10 solvent systems. Possible extensions of this chemistry are discussed.
Walking the Tightrope: An Assessment of the Relationship between High-Performance Work Systems and Organizational Ambidexterity

This study explores central questions related to the connections between a firm's human resources (HR) system and its ability to exhibit "organizational ambidexterity." We build from existing work on the behavioral view of ambidexterity to assess the extent to which the utilization of certain HR practices may be linked to a context marked by discipline, stretch, trust, and support. We further argue that these disparate practices may be combined into a single high-performance work system (HPWS), which allows the firm to achieve both the alignment and the adaptability necessary to produce ambidexterity. Thus, we examine HPWS as a systematic tool for enhancing organizational ambidexterity. We explore this link using data from 215 high-tech small to medium-sized enterprises (SMEs) and find that HPWS utilization is positively related to a measure of organizational ambidexterity. In turn, ambidexterity mediates the relationship between HPWS utilization and firm growth. [ABSTRACT FROM AUTHOR]
Endogenous expectation formation methods: Evidence from consumers' inflation expectations

Abstract This paper analyzes qualitative survey data on consumers' inflation expectations with the multinomial probit model. The results provide evidence that consumers' expectations depend on monetary and fiscal policy data, unemployment rates and pas inflation rates and that consumers' forecast differently during periods of low and high inflation rates. The analysis indicates that the government policy data, especially money growth rates, had a larger impact on the expectations during periods of high inflation. The paper provides support for the hypothesis that expectation formation methods depend on economic conditions.
TRANSCRIPTIONAL CONTROL OF THE OSTEOCALCIN GENE BY 1,25-DIHYDROXYVITAMIN D-2 AND ITS 24-EPIMER IN RAT OSTEOSARCOMA CELLS

Abstract The effects of two vitamin D analogs, 1,25-dihydroxyvitamin D-2 and 24-epi-1,25-dihydroxyvitamin D-2, were examined on osteocalcin gene expression in the rat osteosarcoma cell line ROS 17/2.8. our results indicate that these analogs are more transcriptionally active than 1,25-dihydroxyvitamin D-3, particularly the 24-epimer. Assessment of reporter gene chloramphenicol acetyltransferase (CAT) activity, using the vitamin D responsive element (VDRE) derived from the human osteocalcin gene promoter, revealed that both analogs stimulated CAT activity 5- to 10-fold. 1,25-Dihydroxyvitamin D-2 was slightly more active than 1,25-dihydroxyvitamin D-3, while the 24-epimer was twice as effective. 1,25-Dihydroxyvitamin D-3 also stimulated osteocalcin mRNA accumulation by 2-fold over vehicle-treated cells, 1,25-dihydroxyvitamin D-2 by 2.5-fold, and 24-epi-1,25-dihydroxyvitamin D-2 by 4-fold. Electrophoretic mobility shift assays using the osteocalcin vitamin D responsive element revealed no increase in DNA binding with either analog when compared to 1,25-(OH)2D3. Examination of CAT activity using the rat 24-hydroxylase VDRE indicated no significant difference in transcription with these compounds, suggesting that the vitamin D-2 analogs preferentially activate osteocalcin gene expression.
Emergent Principles for the Design, Implementation, and Analysis of Cluster-Based Experiments in Social Science:

In experimentally designed research, many good reasons exist for assigning groups or clusters to treatments rather than individuals. This article discusses them. But cluster-level designs face some unique or exacerbated challenges. The article identifies them and offers some principles about them. One emphasizes how statistical power and sample size estimation depend on intraclass correlations, particularly after conditioning on the use of cluster-level covariates. Another stresses assigning experimental units at the lowest level of aggregation possible, provided this does not subtly change the research question. A third emphasizes the utility of minimizing and measuring interunit communication, though neither is easy to achieve. A fourth advises against experiments that are totally black box and so leave program implementation and process unstudied, though such study often makes the research process more salient. The last principle involves the utility of describing treatment heterogeneity and estimating...
Biological controls in mixed trichostrongyle infections.

The parasite reaction phenotype of 80 lambs was determined with natural infection on pasture. These lambs were then assigned to outcome groups and randomized into treatment groups. Developing some simple but unusual analytical techniques it was possible to demonstrate that mixed natural infections of trichostrongyles with the chief biomass component Haemonchus contortus cayugensis protected against superinfections with 35000 infective larvae but protected against superinfections with 1000 infective larvae per day only within the limits characteristic of the enclosing barn ecosystem. The limits of the barn ecosystem were less constraining on more diathetic sheep than the natural pasture infection. Internal evidence from the experiment suggests that the interaction of sheep × pasture × infective trichostrongylid larvae constrains the parasite biomass in the host in more diathetic animals at significantly lower levels. Anaphylactoid ‘self-cure’ did not occur in this experiment but something like premunition certainly did.
Investigation of Acid-Base Equilibria for Symmetrically Substituted P,P′-Dialkyl Partial Esters of Bisphosphonic Acids

Bisphosphonic acids are powerful metal chelating reagents with a wide spectrum of applications. A series of partial ester derivatives of bisphosphonic acids was synthesized in order to investigate the physico-chemical changes induced by partial protection of the acid groups. The acid dissociation constants K1 and K2 for a homologous series of short-chain aqueous-soluble dibasic bisphosphonic acids, i.e., the P,P′-diethyl methylene-, ethylene- and propylene-bisphosphonic acid partial esters, H2DEt[MBP], H2DEt[EBP] and H2DEt[PrBP], respectively, were determined by potentiometric titration and 31P NMR spectrometry. All three diethyl esters are rather acidic with pK1 < 1.2 and pK2 < 2.2. The influence of the separation between the phosphonate groups on ligand acidity and successive pKa values is rationalized in terms of solvation, inductive and electrostatic effects.
Fiscal policy, profits and investment: some additional evidence

This article provides time series evidence on the effects of fiscal policy on profits and investment in the US. In addition to neoclassical models of investment and profits we also consider Keynesian models. Our findings provide some support for the neoclassical views. However, Keynesian explanations, which allow for the effects of the real interest rate, receive strong support from the data.
Ultrasonic particle-concentration for sheathless focusing of particles for analysis in a flow cytometer.

Background: The development of inexpensive small flow cytometers is recognized as an important goal for many applications ranging from medical uses in developing countries for disease diagnosis to use as an analytical platform in support of homeland defense. Although hydrodynamic focusing is highly effective at particle positioning, the use of sheath fluid increases assay cost and reduces instrument utility for field and autonomous remote operations. Methods: This work presents the creation of a novel flow cell that uses ultrasonic acoustic energy to focus small particles to the center of a flowing stream for analysis by flow cytometry. Experiments using this flow cell are described wherein its efficacy is evaluated under flow cytometric conditions with fluorescent microspheres. Results: Preliminary laboratory experiments demonstrate acoustic focusing of flowing 10-μm latex particles into a tight sample stream that is ∼40 μm in diameter. Prototype flow cytometer measurements using an acoustic-focusing flow chamber demonstrated focusing of a microsphere sample to a central stream ∼40 μm in diameter, yielding a definite fluorescence peak for the microspheres as compared with a broad distribution for unfocused microspheres. Conclusions: The flow cell developed here uses acoustic focusing, which inherently concentrates the sample particles to the center of the sample stream. This method could eliminate the need for sheath fluid, and will enable increased interrogation times for enhanced sensitivity, while maintaining high particle-analysis rates. The concentration effect will also enable the analysis of extremely dilute samples on the order of several particles per liter, at analysis rates of a few particles per second. Such features offer the possibility of a truly versatile low-cost portable flow cytometer for field applications. © 2005 Wiley-Liss, Inc.
The value of meetings.

HE 50TH ANNIVERSARY of the British Association of Pediatric Surgeons (BAPS) comes early in the new millennium —a time characterized by spectacular new scientific discoveries and advances in information technology and global communication that presents challenges to medical organizations in the future. Medical knowledge can now be accessed electronically and rapidly through web sites on the Internet with the added convenience of choosing the time and place to connect (in the office, at home, in the evening, or on a weekend). In the current era, physicians do not necessarily have to go to a meeting to acquire new information. This may help avoid the expenses related to travel, registration fees, lodging, food, and the potential loss of professional income by missing work when one is out of town attending a meeting. The emergence of pediatric surgical subspecialties (pediatric urology, otolaryngology, and the minimally invasive specialists) has resulted in some splintering from the main body of broadly based pediatric surgery. Some of these special interest physicians may attend more focused meetings in these more narrow areas that may adversely affect meeting attendance and the desire of new pediatric surgical subspecialists to join groups with a more global interest. There is an observed trend in
The Shape-Time Random Field for Semantic Video Labeling

We propose a novel discriminative model for semantic labeling in videos by incorporating a prior to model both the shape and temporal dependencies of an object in video. A typical approach for this task is the conditional random field (CRF), which can model local interactions among adjacent regions in a video frame. Recent work has shown how to incorporate a shape prior into a CRF for improving labeling performance, but it may be difficult to model temporal dependencies present in video by using this prior. The conditional restricted Boltzmann machine (CRBM) can model both shape and temporal dependencies, and has been used to learn walking styles from motion- capture data. In this work, we incorporate a CRBM prior into a CRF framework and present a new state-of-the-art model for the task of semantic labeling in videos. In particular, we explore the task of labeling parts of complex face scenes from videos in the YouTube Faces Database (YFDB). Our combined model outperforms competitive baselines both qualitatively and quantitatively.
Inhibition of fibrin(ogen) binding to stimulated platelets by a monoclonal antibody specific for a conformational determinant of GPIIIa.

Abstract We have purified the integrin GPIIb:IIIa from the membrane fraction of human blood platelets by lentil lectin affinity chromatography followed by gel filtration chromatography. With purified GPIIb:IIIa as an antigen, we have produced monoclonal antibody CS-1, which immunoblotting demonstrates to be specific for native GPIIIa; disulfide bond reduction of GPIIIa resulted in loss of immunoreactivity. Radiolabelled ligand binding studies revealed that CS-1 recognized approximately 55,000 sites per platelet and bound with a Kd in the nanomolar range, independent of the state of platelet activation. Binding of CS-1 or its Fab fragment to ADP-and thrombin-stimulated gel filtered platelets caused a 2–3 fold inhibition of binding the soluble ligands fibrinogen and fibrin protofibrils. CS-1 also inhibited aggregation of ADP- and thrombin-stimulated platelets by 2- and 4-fold, respectively. Since CS-1 inhibits fibrin(ogen) interactions with GPIIb:IIIa, we propose that the conformationally dependent epitope on GPIIIa recognized by CS-1 constitutes a region of the receptor which is involved in fibrin(ogen) binding.
Non‐equilibrium effects in steady relativistic e+e−γ winds

We consider an ultrarelativistic wind consisting of electron–positron pairs and photons with the principal goal of finding the asymptotic Lorentz factor γ∞ for zero baryon number. The wind is assumed to originate at radius ri where it has a Lorentz factor γi and a temperature Ti sufficiently high to maintain pair equilibrium. As r increases, T decreases and becomes less than the temperature corresponding to the electron mass me, after which non-equilibrium effects become important. The pairs, which carry only a small fraction of the total energy, may be accelerated by the photons until τ falls below ∼2 × 10−5γ3/4i. Radiative transfer calculations show that only at this point do the radiation flux and pressure start to deviate significantly from their blackbody values. The acceleration of the pairs increases γ by a factor ∼45 compared with its value at the photosphere; it is shown to approach γ∞ ∼ 1.4× 103(r6i/10 cm)1/4γ{3/4}iTi/me. The limit of zero baryon number is a good approximation when the mass injection rate M˙ in the flow is below a critical value corresponding to (E˙/M˙M)c,0 ∼ 5 × 107(r6i/10 cm)Ti/me for fixed energy injection rate E˙E. For large baryon loading, (E˙/M˙ ≲ E˙/M˙)c,M ∼ 350(ri/106 cm)1/4γ3/4iTi/me, the asymptotic Lorentz factor is γ∞ ∼ E˙/M˙. Surprisingly, increasing E˙/M˙ from (E˙/M˙)c,M to ∞ only increases γ∞ by a factor ∼(mp/me)1/4≈6.5, less than an order of magnitude. As E˙/M˙ increases, the fraction of the energy carried by pairs decreases, reaching ∼10−5γ3/4i as E˙/M˙ to ∞.
SOLID-STATE HIGH VOLTAGE MODULATOR AND ITS APPLICATION TO RF SOURCE HIGH VOLTAGE POWER SUPPLIES

Abstract A solid-state high voltage modulator is described in which series-connected insulated-gate bipolar transistors (IGBTs) are switched at a fixed frequency by a pulse width modulation (PWM) regulator, that adjusts the pulse width to control the voltage out of an inductor–capacitor filter network. General Atomics proposed the HV power supply (HVPS) topology of multiple IGBT modulators connected to a common HVdc source for the large number of 1 MW klystrons in the linear accelerator of the Accelerator Production of Tritium project. The switching of 24 IGBTs to obtain 20 kVdc at 20 A for short pulses was successfully demonstrated. This effort was incorporated into the design of a −70 kV, 80 A, IGBT modulator, and in a short-pulse test 12 IGBTs regulated −5 kV at 50 A under PWM control. These two tests confirm the practicality of solid-state IGBT modulators to regulate high voltage at reasonable currents. Tokamaks such as ITER require large rf heating and current drive systems with multiple rf sources. A HVPS topology is presented that readily adapts to the three rf heating systems on ITER. To take advantage of the known economy of scale for power conversion equipment, a single HVdc source feeds multiple rf sources. The large power conversion equipment, which is located outside, converts the incoming utility line voltage directly to the HVdc needed for the class of rf sources connected to it, to further reduce cost. The HVdc feeds a set of IGBT modulators, one for each rf source, to independently control the voltage applied to each source, maximizing operational flexibility. Only the modulators are indoors, close to the rf sources, minimizing the use of costly near-tokamak floor space.
Monitoring Student Engagement for Intercollegiate Athletics Program Review.

Purpose – The purpose of this study is to examine the impact that athletics participation in both revenue and non‐revenue intercollegiate sport had on the engagement of students as measured by the National Survey of Student Engagement. In addition, the study reported results to the institution's athletics department for application as a tool for program review.Design/methodology/approach – The study employed a factorial design using self‐reported data from a cooperating institution. The independent variables examined were participation in intercollegiate athletics (athletes vs non‐athletes) and the sport type (revenue sports vs non‐revenue sports). Measures of student engagement were the dependent variables in the study.Findings – Descriptive analysis revealed that athletes were as engaged as their non‐athlete peers and suggested that revenue sport participants were not as engaged as their non‐revenue sport counterparts. Univariate ANCOVA analyses uncovered significant differences between both categories ...
Toward the Ideal Study Guide: an exploration of the functions and components of study guides

The study guide, as an important resource for student learning, is here conceptualized in an ideal general form. The process starts with an examination of its instructional context, then explores the learning functions it is meant to support. This in turn leads to a sketch of the practical components which can be employed in the design of a study guide, with a discussion of various practical decisions to be made along the way. The ideal study guide which is developed here is only meant as a prototype, a template of sorts for particular instructional design efforts in study guide development.
Amyloid-beta and Alzheimer’s disease: the role of neprilysin-2 in amyloid-beta clearance

Accumulation of the amyloid-beta (Aβ) peptide is a central factor in Alzheimer's disease (AD) pathogenesis as supported by continuing evidence. This review concisely summarizes this evidence supporting a critical role for Aβ in AD before discussing the clearance of this peptide. Mechanisms of clearance of Aβ are critical for preventing pathological elevations in Aβ concentration. Direct degradation of Aβ by endopeptidases has emerged as one important pathway for clearance. Of particular interest are endopeptidases that are sensitive to the neprilysin (NEP) inhibitors thiorphan and phosphoramidon (i.e., are "NEP-like") as these inhibitors induce a dramatic increase in Aβ levels in rodents. This review will focus on neprilysin-2 (NEP2), a NEP-like endopeptidase which cooperates with NEP to control Aβ levels in the brain. The evidence for the involvement of NEP2 in AD is discussed as well as the therapeutic relevance with regards to gene therapy and the development of molecular markers for the disease.
From Genetics to Genomics: Ethics, Policy, and Parental Decision-making

Objective Ethical evaluation of genetic testing in children is traditionally based on balancing clinical benefits and risks. However, this focus can be inconsistent with the general practice of respecting parental decision-making about their children’s health care. We argue that respect for parental decision-making should play a larger role in shaping pediatric genetic testing practices, and play a similar role regarding decisions to use emerging genomic technologies. Methods Genomic testing involves the examination of thousands of DNA markers spanning genes throughout the genome and their interrelationships, yielding virtually limitless interpretations. We presume that parents and providers should proceed cautiously in applying genomic testing in children, as we explore how genomic testing will stress the fault lines of the traditional ethical analysis. Results Empirical data about the psychosocial risks and benefits of genetic testing of children do not reveal serious harms, yet virtually no such data exist yet about genomic testing. Unless empirical social and behavioral data indicate that genomic testing is highly likely to cause serious harms to the children, parental decisions to obtain comprehensive genomic testing in their children should be respected. Once comprehensive genomic testing of children becomes routine, resultant information may be more easily integrated by families than anticipated. Conclusions Research on the social and behavioral impact of comprehensive genomic testing on children and their families is needed to further inform parents, clinicians, and policy makers.
R-wave triggering of external instrumentation during cardiac pacing.

Monitoring and diagnostic instruments often utilize electrocardiographic R-wave detection for measuring hearl rate or for timing of measurement processes. During cardiac pacing stimulus artifacts commonly interfere with the operation of such instruments because they are misinterpreted as R-waves. This phenomenon creates problems in assessing the hernodynamics during gated blood-pool scans, coronary care monitoring, and intra-aorlic balloon pumping. A straightforward solution is found in the nature of the electrical signals involved in which the stimulus artifacts are detected independently and are removed from the signal fed to the R-wave detector.
Reciprocal suffering: caregiver concerns during hospice care.

Context For many hospice caregivers, the constancy and difficulty of caregiving impact their physical quality of life and cause depression, psychological distress, guilt, loneliness, and restrictions on social activities.
An efficient computational method for characterizing the effects of random surface errors on the average power pattern of reflectors

Based on the works of Ruze and Vu, a novel mathematical model has been developed to determine efficiently the average power pattern degradations caused by random surface errors. In this model, both nonuniform root mean square (rms) surface errors and nonuniform illumination functions are employed. In addition, the model incorporates the dependence on F/D in the construction of the solution. The mathematical foundation of the model rests on the assumption that in each prescribed annular region of the antenna, the geometrical rms surface value is known. It is shown that closed-form expressions can then be derived, which result in a very efficient computational method for the average power pattern. Detailed parametric studies are performed with these expressions to determine the effects of different random errors and illumination tapers on parameters such as gain loss and sidelobe levels. The results clearly demonstrate that as sidelobe levels decrease, their dependence on the surface rms/ \lambda becomes much stronger and, for a specified tolerance level, a considerably smaller rms/ \lambda is required to maintain the low sidelobes within the required bounds.
Is Pornography a Problem?1

Twenty-three experimental subjects were exposed to pornographic materials for 90 minutes per day for 15 days. Extensive pre and post testing of attitudes and behavior showed no detrimental effect of this exposure either in terms of change on any measure or with regard to a control group (N = 9). Behavioral and physiological measures demonstrated that this massive exposure to pornography resulted in much lowered interest in it and much less response to it. It is concluded that pornography is an innocuous stimulus which leads quickly to satiation and that public concern over it is misplaced.
MAC Protocols for Optical Orthogonal Frequency Division Multiple Access (OFDMA)-based Passive Optical Networks

A novel passive optical network (PON) architecture based on optical orthogonal frequency division multiple access (OFDMA) technologies is presented. Two potential medium access control (MAC) methods namely dynamic circuit transmission and fixed burst transmission are investigated.
Persistent depressive symptoms lower aspirin adherence after acute coronary syndromes.

Background Even mild depressive symptoms during hospitalization are an independent risk factor for mortality after acute coronary syndromes (ACS). The mortality risk is highest for patients whose depressive symptoms persist after ACS. Low adherence to medications that reduce the risk of subsequent cardiac events may be one of the mechanisms underlying the relationship between persistent depression and risk of ACS recurrence. We compared electronically monitored adherence to aspirin in 3 groups of patients with ACS: persistently depressed, remittent depressed, and persistently nondepressed. Methods Using an electronic device stored in the cap of a pill bottle, we monitored aspirin adherence over a 3-month period in 165 consecutive patients recruited within 1 week of an ACS event. Depressive symptom severity was assessed by using the Beck Depression Inventory at baseline and at 3 months. Adherence was determined by the percentage of days aspirin was taken as prescribed. Results Among the patients, 10.5% of nondepressed patients, 9.8% of remittent depressed patients, and 42.1% of persistently depressed patients took aspirin ≤75% of the time (P Conclusions Poor medication adherence—a potentially modifiable behavior—may contribute to the high mortality risk observed in patients with persistent symptoms of depression after ACS.
Response to inhibition of smoothened in diverse epithelial cancer cells that lack smoothened or patched 1 mutations

Hedgehog (HH) pathway Smoothened (Smo) inhibitors are active against Gorlin syndrome-associated basal cell carcinoma (BCC) and medulloblastoma where Patched (Ptch) mutations occur. We interrogated 705 epithelial cancer cell lines for growth response to the Smo inhibitor cyclopamine and for expressed HH pathway-regulated species in a linked genetic database. Ptch and Smo mutations that respectively conferred Smo inhibitor response or resistance were undetected. Previous studies revealed HH pathway activation in lung cancers. Therefore, findings were validated using lung cancer cell lines, transgenic and transplantable murine lung cancer models, and human normal-malignant lung tissue arrays in addition to testing other Smo inhibitors. Cyclopamine sensitivity most significantly correlated with high cyclin E (P=0.000009) and low insulin-like growth factor binding protein 6 (IGFBP6) (P=0.000004) levels. Gli family members were associated with response. Cyclopamine resistance occurred with high GILZ (P=0.002) expression. Newer Smo inhibitors exhibited a pattern of sensitivity similar to cyclopamine. Gain of cyclin E or loss of IGFBP6 in lung cancer cells significantly increased Smo inhibitor response. Cyclin E-driven transgenic lung cancers expressed a gene profile implicating HH pathway activation. Cyclopamine treatment significantly reduced proliferation of murine and human lung cancers. Smo inhibition reduced lung cancer formation in a syngeneic mouse model. In human normal-malignant lung tissue arrays cyclin E, IGFBP6, Gli1 and GILZ were each differentially expressed. Together, these findings indicate that Smo inhibitors should be considered in cancers beyond those with activating HH pathway mutations. This includes tumors that express genes indicating basal HH pathway activation.
Adolescent beverage habits and changes in weight over time: findings from Project EAT

Background: Obesity in adolescence has been increasing in the past several decades. Beverage habits among adolescents include increased consumption of sugar-sweetened beverages and decreased consumption of milk. Objective: This study aimed to examine the association between beverage consumption and 5-y body weight change in 2294 adolescents. Design: Project EAT (“Eating Among Teens”) is a 5-y longitudinal study of eating patterns among adolescents. Surveys were completed in 1998–1999 (time 1) and in 2003–2004 (time 2). Multivariable linear regression was used to examine the association between beverage consumption at time 2 and change in body mass index from time 1 to time 2, with adjustments for age, socioeconomic status, race, cohort, physical activity, sedentary behavior, coffee, tea, time 1 body mass index, and beverage variables. Results: In prospective analyses, consumption of beverages was not associated with weight gain, except for consumption of low-calorie soft drinks (positive association, P = 0.002) and white milk (inverse association, P = 0.03), but these associations did not appear to be a monotonic linear dose-response relation. The positive association with low-calorie soft drinks was no longer present after adjustment for dieting and parental weight-related concerns, which suggests that the use of low-calorie soft drinks is a marker for more general dietary behaviors and weight concerns. Conclusions: We showed no association between sugar-sweetened beverage consumption, juice consumption, and adolescent weight gain over a 5-y period. A direct association between diet beverages and weight gain appeared to be explained by dieting practices. Adolescents who consumed little or no white milk gained significantly more weight than their peers who consumed white milk. Future research that examines beverage habits and weight among adolescents should address portion sizes, adolescent maturation, and dieting behaviors. Am J Clin Nutr doi: 10.3945/ajcn.2009.27573.
Pre-discharge iron status and its determinants in premature infants.

Objective: To evaluate pre-discharge iron status and identify its determinants in infants’ ≤ 32 weeks gestational age (GA). Methods: In a prospective observational study, 24–32 weeks GA infants who...