cssi/SciSciGPT-SciSciNet huggingface dataset:
Fluid-filled dynamic bowtie filter: a feasibility study

By varying its thickness to compensate for the different path length through the patient as a function of fan angle, a pre-patient bowtie filter modulates flux distribution to reduce patient dose, scatter, and detector dynamic range, and to improve image quality. A dynamic bowtie filter is superior to its traditional, static counterpart in its ability to adjust its thickness along different fan and view angles to suit a specific patient and task. Among the proposed dynamic bowtie designs, the piecewise-linear and the digital beam attenuators offer more flexibility than conventional filters, but rely on analog positioning of a limited number of wedges. In this work, we introduce a new approach with digital control, called the fluid-filled dynamic bowtie filter. It is a two-dimensional array of small binary elements (channels filled or unfilled with attenuating liquid) in which the cumulative thickness along the x-ray path contributes to the bowtie’s total attenuation. Using simulated data from a pelvic scan, the performance is compared with the piecewise-linear attenuator. The fluid-filled design better matches the desired target attenuation profile and delivers a 4.2x reduction in dynamic range. The variance of the reconstruction (or noise map) can also be more homogeneous. In minimizing peak variance, the fluid-filled attenuator shows a 3% improvement. From the initial simulation results, the proposed design has more control over the flux distribution as a function of both fan and view angles.
On the initial distribution in kaonic atoms

Abstract A comparison of two recent kaonic X-ray experiments indicates that the initial distribution of K − in the vicinity of the electronic K shell in kaonic atoms has a substantial low angular momentum excess which cannot be accomodated by the conventional parametrization, (2 l + 1) exp ( αl ).
Three-dimensional laser velocimeter investigation of turbulent, incompressible flow in an axisymmetric sudden expansion

An experimental study of the flow in an axisymmetric sudden expansion was carried out using a three-color, three-component laser Doppler velocimeter with computer controlled data acquisition and reduction. The area ratio of the expansion was 121:1 and the Reynolds number, which was based on inlet average velocity and inlet diameter, was 22,000. The axial, radial, and circumferential components of the mean velocity were computed from the measurement of three independent velocity components as were the turbulence intensities and kinetic energy. The results showed the flow to be axisymmetric, with negligible circumferential mean velocity. The nature of the separated flow region was consistent with that of previous studies. The large area ratio had little effect on the location of the reattachment, which occurred approximately six step heights downstream of the expansion. All three normalized turbulence intensities were shown to be of the same order of magnitude, thus showing nearly isotropic turbulence. The centerline velocity decay for this large area ratio was much more rapid than the decay for smaller area ratios and was similar to that of a free jet exhausting to atmospheric pressure.
ON THE NOTION OF DISTANCE REPRESENTING INFORMATION CLOSENESS: Possibility and Probability Distributions

A metric distance based on information variation a derived in this paper for possibility distributions (function G defined by (6), where g is defined by (2) and U is defined by (1)). It is applicable to any pair of normalized possibility distributions defined on a finite set X and either it is unique or, if not unique, it represents the maximum distance in the class of such metric distances. It is an open problem lo either derive (his class or to prove the uniqueness of our distance. A similar measure; based on the well-known directed information divergence, is proposed for probability distributions defined on a finite set (function D defined by (12), where d is defined by (11)). The measure is nondegenerate and symmetric and it is our conjecture, supported by empirical evidence, that it also satisfies the triangle inequality requirement of metric distances, A mathematical proof of this conjecture remains an open problem.
Colorectal laceration after manual-anal intercourse

Injuries and illnesses related to changing sexual behaviors are being reported with increasing frequency. A practice found predominantly in the homosexual community, "handballing," may result in occult but serious colorectal trauma. Described is the case of a 31-year-old man who presented with an acute abdomen due to colorectal laceration secondary to handballing. After emergency surgical repair, he had an uneventful recovery, and returned once for elective colostomy closure.
Translesional synthesis on a DNA template containing a single stereoisomer of dG-(+)- or dG-(-)-anti-BPDE (7, 8-dihydroxy-anti-9, 10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene

Oligodeoxynucleotides modified site-specifically with dG-(+)-trans- and dG-(+)-cis-anti-BPDE (7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene) or dG-(-)-trans- and dG-(-)-cis-anti-BPDE were used as templates in primer extension reactions catalyzed by the Klenow fragment of Escherichia coli DNA polymerase I. The primer could be extended past the dG-(-)-trans-BPDE adduct with small amounts of dAMP incorporated opposite the lesion. A small amount of base deletions was also observed while, with the dG-(-)-cis-BPDE adduct, one- and two-base deletions predominated. When templates containing dG-(+)-trans-BPDE were used, small amounts of products containing one-base deletions were observed; with dG-(+)-cis-BPDE, substitution of dAMP opposite the lesion was also detected. The frequency of nucleotide insertion for dAMP opposite dG-(-)-trans-BPDE and the frequency of extension from the primer terminus containing the dA:dG-(-)-trans-BPDE pair were much higher than those observed with the other, stereochemically different BPDE adducts. Kinetic studies were in agreement with the results of the primer extension study. When the base flanking the 5' side of dG-BPDE was changed from dC to dT, the frequency of one-base deletions increased. We conclude that the trans- or cis-addition product of dG-(-)-anti-BPDE has a higher miscoding potential than dG-(+)-anti-BPDE in our model system and that G-->T transversions and deletions predominate. These observations are consistent with the types of mutations observed in vivo.
Origin and differentiation of Triassic dolerite magmas, North Carolina, USA

Ten dolerite dikes intruded into Triassic fault troughs in the Piedmont area of North Carolina have been analyzed for the contents of major elements plus selected trace elements. The average composition of the initial magma, as indicated by four chill margins for major elements and three for trace elements, is: SiO2, 48.6%; Al2O3, 16.9%; TiO2, 0.57%; Fe2O3, 3.30%; FeO, 6.72%; MgO, 10.59; CaO, 10.42%; Na2O, 2.03%; K2O, 0.20%; MnO, 0.20%; Rb, 2.6 ppm; Sr, 133 ppm; Zr, 46 ppm; Th, 0.4 ppm; and U, below detection limit of approximately 0.1 ppm. One large dike (BP) exhibits a Palisades-type of differentiation by crystal settling of olivine, and the comparatively thick JY dike shows development of micropegmatite toward the center; the smaller dikes, however, are relatively homogeneous across their width. Study of the relationship between SiO2 content and the ratio FeO+Fe2O3/MgO+ FeO+Fe2O3 indicates that most dikes crystallize under conditions of decreasing oxygen pressure, but the differentiation trend of the JY, RD, and RS dikes indicates either constant or increasing oxygen pressure during their evolution.
GOVERNANCE PATTERNS IN BANKRUPTCY REORGANIZATIONS

Recent research has suggested that effective monitoring may assist firms in preventing an eventual bankruptcy filing. Audit committees, board subgroups responsible for monitoring and evaluating the financial health of the firm, may exhibit varying degrees of effectiveness in monitoring firms' decline as a function of their composition. Another monitoring body which has become increasingly important in the corporate community is institutional investors. This study investigates the extent to which audit committee composition and institutional investor holdings are related to the incidence and nature (prepackaged plans and length of time spent in reorganization) of firms' bankruptcy filings. Results demonstrate no association between affiliated director representation on audit committees or institutional holdings and the incidence of bankruptcy. These two monitoring groups are, however, associated with the nature of bankruptcy filing. Both audit committee composition and the level of institutional holdings are significantly related to a prepackaged filing and the length of time spent in reorganization during the 5-year period preceding a bankruptcy filing.
Substrate controls on the longitudinal profile of bedrock channels: Implications for reach‐scale roughness

[1] In this paper we examine the relationships among bedrock properties and hydraulics in shaping bedrock channel morphology at the reach scale. The Ocoee River and four other bedrock streams in the Blue Ridge province of the southeastern United States, which have reach-scale differences in bedrock erodibility controlled by lithologic and structural variation, are the focus of this study. We describe a simple conceptual model for concentrated erosion in bedrock channels and test three hypotheses in order to investigate the interactions among rock erodibility, characteristics of undulating rib-like bed forms, reach-scale gradient, and hydraulic roughness and energy dissipation. Substrate differences correlate with variation in reach morphology (i.e., gradient, bed form orientation, and amplitude), such that less erodible substrates are associated with steeper reach gradient and with transversely oriented ribs of greater amplitude. One-dimensional modeling in HEC-RAS indicated that in the reach with the least erodible substrate and greatest bed slope and rib amplitude, the reach-averaged hydraulic roughness was the greatest. Increased hydraulic roughness in steeper reaches points to the importance of positive and negative feedbacks in these systems: Greater substrate erosional resistance limits profile lowering, which likely creates steeper bed slopes and greater stream power, creating a self-enhancing feedback. This local increase in stream power is balanced by increased roughness resulting from the erosional processes that produce bedrock ribs, which represents a self-regulating feedback. The overall result reflects quantifiable adjustments between substrate resistance and hydraulic driving forces in bedrock channels.
Air permeability and capillary rise as measures of the pore structure of snow: an experimental and theoretical study

Air permeability and capillary pressure are macroscopic snow properties that are influenced by the pore structure of the snow cover. Formulas for predicting fluid transport, species elution, and acoustive wave propagation require parameterization of one or both of these properties. We report paired measurements of permeability and capillary rise from snow samples at field sites in Hanover. New Hampshire, and Sleepers River Research Watershed. Danville, Vermont. We augment these data with laboratory tests on sieved snow and glass beads. Our measurements demonstrate a linear relationship between permeability and the ratio of porosity and the square of capillary rise, which we corroborate theoretically using a simple conduit model of the pore space We propose that scatter in the data results, in part, from the effect of crystal shape on air flow and imbibitior contact angle. Since the early measurements and classification schemes of Bader in 1939, many investigators have expanded the database of permeability observations for a wide range of snow types. We summarize these data and report our own recent observations from the New England sites and from an additional site in Manitoba, Canada. Our measurements are in the high range of reported values. However, after normalizing our data by the square of grain diameter, they follow the empirical function of Shimizu fairly closely. This agreement supports our measurements, and demonstrates the usefulness of Shimizu's function for snow types other than the relatively dense fine-grained snow used in his analysis. Our normalized permeability data for low density snow, as well as the Shimizu function, are below theoretical predictions for suspensions of spheres and infinite cylinders. By extending the model for spheres to oblate spheroids and discs. we estimate permeability that is in closer agreement with our data. We suggest that a decrease in surface-to-volume ratio as snow ages may account for a relative increase in normalized permeability.
Characteristic classes of discriminants and enumerative geometry

We compute the Euler obstruction and Mather’s Chern class of the discriminant hypersurface of a very ample linear system on a nonsingular variety. Comparing the codimension-1 and 2 terms of this and other characteristic classes of the discriminant leads to a quick computation of the degrees of the loci of cuspidal and binodal sections of a very ample line bundle on a smooth variety, and of the, tacnodal locus for linear systems on a surface. We also compute explicitly all terms in the Schwartz-MacPherson’s classes of strata of the discriminant in the P9of of cubic plane curves, and of the discriminant of∣O(d)∣ on P1.
The CD40/CD40L costimulatory pathway in inflammatory bowel disease

The complexity of inflammatory bowel disease (IBD) is well recognised at both the clinical and therapeutic levels. Even more complex however appears to be the unravelling of its aetiology and pathogenesis where environmental, genetic, bacterial, and immune factors come together to generate the clinical entities we recognise as Crohn’s disease (CD) and ulcerative colitis (UC).1,2 When facing a complex problem, a wise approach is to select first its most obvious part, break it down into its various components, and then try to understand the contribution of each component to the problem. IBD is a chronic inflammatory process and therefore inflammation is the fundamental issue, the mechanism responsible for the tissue damage in CD and UC. If chronic inflammation is the central mechanism, what are its components? To keep the answers simple, one can envision a triggering event that initiates IBD, and a number of subsequent events that maintain inflammation and perpetuate IBD. The initial trigger is probably far more dependent on genetics and environmental factors than the events that perpetuate IBD.3,4 These are more likely to be tissue dependent events and there is little doubt that dysregulation of the local immune response is what underlies gut inflammation and allows it to persist unabated year after year.5 Thus until genetic and environmental factors are fully identified, it seems worthy to investigate the various biological systems that contribute to the chronicity of gut inflammation. The purpose of this review is to discuss one key contributor, the CD40/CD40 ligand (L) system, and present evidence that this system plays a major role in immunity and inflammation, can foster chronic inflammation, is directly relevant to IBD, and its modulation may offer therapeutic benefits to IBD patients. To achieve these aims, it is vital to first understand where the CD40/CD40L system …
Sagittarius A* Polarization: No Advection-dominated Accretion Flow, Low Accretion Rate, and Nonthermal Synchrotron Emission

The recent detection of polarized radiation from Sgr A* requires a nonthermal electron distribution for the emitting plasma. The Faraday rotation measure must be small, placing strong limits on the density and magnetic field strength. We show that these constraints rule out advection-dominated accretion flow models. We construct a simple two-component model that can reproduce both the radio-to-millimeter spectrum and the polarization. This model predicts that the polarization should rise to nearly 100% at shorter wavelengths. The first component, possibly a black hole-powered jet, is compact, low density, and self-absorbed near 1 mm with ordered magnetic field, relativistic Alfven speed, and a nonthermal electron distribution. The second component is poorly constrained, but may be a convection-dominated accretion flow with ~ 10-9 M☉ yr-1, in which feedback from accretion onto the black hole suppresses the accretion rate at large radii. The black hole shadow should be detectable with submillimeter VLBI.
Theoretical Considerations for Finding New Thermoelectric Materials

This paper reviews the connections between the transport properties underlying the thermoelectric performance of a material and microscopic quantities, particularly as they may be obtained from first principles calculations. These are illustrated using examples from work on skutterudites. The results are used to suggest yet to be explored avenues for achieving higher thermoelectric performance within this class of materials.
The T-axial membrane system in striated muscles of the horseshoe crab

Cardiac muscle and skeletal muscles powering walking leg, tailspine and gill movements in Limulus polyphemus were studied by transmission electron microscopy. All muscles examined had extensive invaginations of the sarcolemma at the Z disc and at the lateral margins of the A band. Invaginations at the Z disc were often branched in the transverse and longitudinal planes, but branching was not observed at other locations within a sarcomere. Dyads, and occasional triads, were observed at the A band in all muscles examined.
An estimate of the minimum amount of fluid lipid required for the growth of Escherichia coli.

Abstract The lipid phase transition of Escherichia coli was studied by high sensitivity differential scanning calorimetry. A temperature sensitive unsaturated fatty acid auxotroph was used to obtain lipids with subnormal unsaturated fatty acid contents. From these studies it was concluded that E. coli can grow normally with as much as 20% of its membrane lipids in the ordered state but that if more than 55% of the lipids are ordered, growth ceases. Studies with wild-type cells show that the phase transition ends more than 10°C below the growth temperature when the growth temperature when the growth temperature is either 25°C or 37°C.
Asset-return anomalies in a monetary economy

Abstract This paper provides a general equilibrium, choice theoretic, spatial model which explains the preference for holding barren money rather than interest-bearing securities or capital goods. Put somewhat differently, it examines standard asset pricing relationships in the context of a fully articulated monetary economy and delivers various asset-return anomalies. In seeking to integrate the theory of value with the theory of money, a fairly general proof of the existence of a monetary equilibrium is provided.
Sevoflurane and halothane reduce focal ischemic brain damage in the rat : possible influence on thermoregulation

BackgroundThere has been little systematic examination concerning the comparative effects of the anesthetized versus the awake state on outcome from cerebral ischemia. This experiment evaluated infart volume and neurologic function in rats subjected to temporary focal ishemia while anesthetized with
A speed-up for the commute between subword trees and DAWGs

A popular way to describe and build the DAWG or Directed Acyclic Word Graph of a string is by transformation of the corresponding subword tree. This transformation, which is not difficult to reverse, is easy to grasp and almost trivial to implement except for the assumed implication of a standard tree isomorphism algorithm. Here we point out a simple property of subword trees that makes checking tree isomorphism in this context a straightforward process, thereby simplifying the transformation significantly. Subword trees and DAWGs arise rather ubiquitously in applications of string processing, where they often play complementary roles. Efficient conversions are thus especially desirable.
Clinical assessment of psychiatric consultations in a medical long-term care facility: Interrater reliability for DSM-III diagnostic groups

The reliability of the DSM-III diagnostic system was assessed in a medical long-term care facility population that was recently seen in psychiatric consultation. Six standard rating scales were used to determine interrater agreement for perceiving psychopathology prior to selecting diagnoses. The findings were that six major diagnostic groups could be accurately distinguished from one another: no disorder; organic mental disorders; affective disorders; paranoid disorders; schizophrenia and psychotic disorders not elsewhere classified; and a mixed group of other diagnoses that occurred in low frequency in this study population. The interrater reliability (kappa = 0.64–0.70) was comparable to that found in the general psychiatric population.
Opioids protect against substantia nigra cell degeneration under conditions of iron deprivation: A mechanism of possible relevance to the Restless Legs Syndrome (RLS) and Parkinson's Disease

Abstract Hypofunction of the endogenous opioid, dopamine and iron systems are implicated in the pathogenesis of Restless Legs Syndrome (RLS). Therefore, we probed the interrelationship of these 3 systems in an in vitro model. Cell cultures of the substantia nigra (SN) of Sprague–Dawley rats were established and the cells were determined to be primarily dopaminergic. The numbers of cells surviving under different concentrations of the iron chelator desferoxamine were reduced in a concentration and time dependent manner (p d -Ala2, d -Leu5]Enkephalin (DADLE) significantly protected the SN cells from damage by iron deficiency (n = 6, p
Forces between surfaces with surface-specific interactions in a dilute electrolyte

Abstract We have investigated the forces between two surfaces, immersed in a dilute electrolyte solution, interacting specifically with the ions that are in their immediate vicinity. It is found that at large separations the free energy decays exponentially (the decay length being approximately half the Debye length) with separation, while the magnitude of the force depends on the physical properties of the surfaces and their interactions with the nearby ions. This long-range attractive force could well represent a case for the electrostatic nature of the surface-specific very long-range “hydrophobic” interaction.
Responses to labeling attempts: Deviant drinkers’ pathways of label manipulation

Recognizing the traditional labeling approach's view of the label recipient as a passive participant in the labeling process, this paper argues that the symbolic interactional roots of this approach indicate this to be an inappropriate formulation. Rather, it is suggested that label recipients are active participants in the process and their major goal is the reduction of stigma and limited conforming opportunities inherent in label application. For the deviant drinker, there are two available pathways of label negotiation. With initial labeling attempts, it is hypothesized that label recipients should attempt to negotiate reality through deviance avowal, whereas with increasing numbers of prior labeling attempts, deviance avowal becomes the only viable means of reality negotiation. Because of the medicalization of deviant drinking, deviance avowal becomes a means of reducing label‐based social costs through occupation of the repentant‐deviant role. Given the need to invoke certain aspects of the medicall...
Relating the SPICE framework and SEI approach to software process assessment

In June 1993, an international effort (SPICE) was launched to develop a standard for software process assessment. An important goal of this effort is to harmonize existing process assessment approaches. This paper describes and characterizes SEI and SPICE software process assessment work and then highlights the similamties and differences. The following aspects are considered-underlying philosophy, goals, scope/domain, rating processes, underlying reference model, tailorability and impact on the international software community.
Impulsivity ratings in bulimia nervosa: relationship to binge eating behaviors

Although impulsive behavioral patterns are often described by patients with bulimia nervosa, there has been little formal evaluation of the relationship between impulsivity and eating-related symptomatology in this disorder. In this controlled outpatient study, ratings on the Barratt Impulsivity Scale were significantly elevated in 20 women with bulimia nervosa in comparison to 20 healthy female volunteers. Frequency of binge eating episodes was not significantly correlated with impulsivity ratings. Although these results indicate increased prevalence of impulsive behavioral style in patients with bulimia nervosa, impulsivity per se does not appear to be a predictor of symptom severity as reflected in frequency of bulimic episodes.
Timing in the Absence of Supraspinal Input II: Regularly Spaced Stimulation Induces a Lasting Alteration in Spinal Function That Depends on the NMDA Receptor, BDNF Release, and Protein Synthesis

The detection of temporal regularity allows organisms to predict the occurrence of future events. When events occur in an irregular manner, uncertainty is increased, and negative outcomes can ensue (e.g., stress). The present study shows that spinal neurons can discriminate between variable- and fixed-spaced stimulation and that the detection of regularity requires training and engages a form of NMDA receptor-mediated plasticity. The impact of stimulus exposure was assessed using a spinally mediated instrumental response, wherein spinally transected rats are given legshock whenever one hindlimb is extended. Over time, they learn to maintain the leg in a flexed position that minimizes net shock exposure. Prior exposure to 180–900 tailshocks given in a variable (unpredictable) manner inhibited this learning. A learning deficit was not observed when 900 tailshocks were applied using a fixed (predictable) spacing. Fixed-spaced stimulation did not have a divergent effect when fewer (180) shocks were presented, implying that the abstraction of temporal regularity required repeated exposure (training). Moreover, fixed-spaced stimulation both prevented and reversed the learning deficit. The protective effect of fixed-spaced shock lasted 48 h, and was prevented by pretreatment with the NMDA receptor antagonist MK-801. Administration of the protein synthesis inhibitor cycloheximide after training blocked the long-term effect. Inhibiting BDNF function, using TrkB-IgG, also eliminated the beneficial effect of fixed-spaced stimulation. The results suggest that spinal systems can detect regularity and that this type of stimulation promotes adaptive plasticity, which may foster recovery after spinal injury.
The role of organ level conditioning on the promotion of engineered heart valve tissue development in-vitro using mesenchymal stem cells

Abstract We have previously shown that combined flexure and flow (CFF) augment engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083–95). In the present study, we sought to determine if these phenomena were reproducible at the organ level in a functional tri-leaflet valve. Tissue engineered valve constructs (TEVC) were fabricated using PGA/PLLA nonwoven fibrous scaffolds then seeded with MSCs. Tissue formation rates using both standard and augmented (using basic fibroblast growth factor [bFGF] and ascorbic acid-2-phosphate [AA2P]) media to enhance the overall production of collagen were evaluated, along with their relation to the local fluid flow fields. The resulting TEVCs were statically cultured for 3 weeks, followed by a 3 week dynamic culture period using our organ level bioreactor (Hildebrand et al., ABME, Vol. 32, pp. 1039–49, 2004) under approximated pulmonary artery conditions. Results indicated that supplemented media accelerated collagen formation (∼185% increase in collagen mass/MSC compared to standard media), as well as increasing collagen mass production from 3.90 to 4.43 pg/cell/week from 3 to 6 weeks. Using augmented media, dynamic conditioning increased collagen mass production rate from 7.23 to 13.65 pg/cell/week (88.8%) during the dynamic culture period, along with greater preservation of net DNA. Moreover, when compared to our previous CFF study, organ level conditioning increased the collagen production rate from 4.76 to 6.42 pg/cell/week (35%). Newly conducted CFD studies of the CFF specimen flow patterns suggested that oscillatory surface shear stresses were surprisingly similar to a tri-leaflet valve. Overall, we found that the use of simulated pulmonary artery conditions resulted in substantially larger collagen mass production levels and rates found in our earlier CFF study. Moreover, given the fact that the scaffolds underwent modest strains (∼7% max) during either CFF or physiological conditioning, the oscillatory surface shear stresses estimated in both studies may play a substantial role in eliciting MSC collagen production in the highly dynamic engineered heart valve fluid mechanical environment.
MHC class-I-restricted CD8 T cells play a protective role during primary Salmonella infection.

Abstract Protective immunity against Salmonella infection is known to require CD4 Th1 cells and B cells, but the role of MHC class-I-restricted CD8 T cells is less clear. Previous studies have suggested that CD8 T cells participate in secondary, but not primary, bacterial clearance. However, these studies have used experimental models that are difficult to interpret and do not clearly isolate the role of MHC class-I-restricted CD8 T cells from other cell populations. Here, we examined the role of class-I-restricted T cells in protection against Salmonella infection using mice lacking all classical MHC class-Ia molecules, perforin, or granzyme B. Immunized K b D b -, perforin-, granzyme B-, or perforin/granzyme B-deficient mice were able to resolve secondary infection with virulent Salmonella , demonstrating that class-I-restricted CTLs are not required for acquired immunity. However, during primary infection with attenuated bacteria, bacterial clearance was delayed in each of these mouse strains when compared to wild-type mice. Taken together, these data demonstrate that CD8 T cells are not required for acquired immunity to Salmonella , but can play a protective role in resolving primary infection with attenuated bacteria.
953-32 Controlled Hypoventilation Increases Pulmonary Vascular Resistance at the Expense of Increased Right Ventricular Work and Oxygen Consumption

Controlled hypoventilation (CH) has been utilized to increase pulmonary vascular resistance (PVR) and limit pulmonary artery blood flow (Opa) in conditions with pulmonary overcirculation and single ventricle physiology. The effects of CH, and subsequent hypercapnia, on the pulmonary circulation, right ventricular performance, and oxygen consumption (VO 2 ) are poorly described. To more precisely define the effects of CH on the cardiopulmonary circulation independent of cardiac shunting, seven swine (30–46 kg) with normal cardiac and pulmonary anatomy were studied. The swine were placed on volume control ventilation with ventilator rates adjusted to maintain PaCO 2 at 35–45 mmHg for normocapnia (NC) and 55–75 mmHg for CH/hypercapnia. Set tidal volume (15 cc/kg), PEEP (3–4 cm H 2 O), and I-time (1 sec) were kept constant. Measurements in both conditions included pulmonary artery pressure (P pa ) by micromanometry and (P pa ) by ultrasonic flow probe. Right ventricular stroke work (SW) was determined by sonomicrometry. Transpulmonary vascular efficiency (TVE), a sensitive indicator of the efficacy of pulmonary blood flow, was calculated by Qpa/total power where total power is the energy the right ventricle imparts in moving blood through the pulmonary vasculature. Measurements were compared by Student's paired t-test with P l 0.05 considered significant. PaCo 2 (mmHg) P pa (mmHg) P pa /P sys (%) PVR (d-s/cm 5 ) TVE (L/W-min) SW VO 2 (ml/min) NC 39 15.6 27 689 25.5 159 69.6 CH 62 * 20.1 * 33 * 907 * 21.0 * 201 * 90.5 * * significant vs. normocapnia CH significantly increases PVR but accomplishes this at the expense of increased right ventricular work, decreased TVE, and increased oxygen consumption. The potentially detrimental effects of CH on cardiorespiratory performance must be appreciated when applying this therapy to clinical conditions with unstable physiology.
Modification of the centerline method for assessment of echocardiographic wall thickening and motion: A comparison with areas of risk

Abstract The abilility of the centerline method to discern regional myocardial risk area was evaluated using two-dimensional echocardiographic measurements and coronary artery occlusion in 16 open chest, anesthetized dogs. The centerline method was modified to allow determination of both wall thickening and wall motion at control and during coronary artery occlusion. End-systolic and end-diastolic echocardiographic images were analyzed at 100 equally spaced points around the centreline of the short axis view of the left ventricle to determine shortening and thickening abnormalities. In vivo risk regions were assessed by microsphere injection during occlusion, and autoradiographic analysis revealed a mean (± SD) circumferential risk area of 37.5± 7.7%. Abnormal function was established by three criteria on the basis of the control values for both fractional shortening and wall thickening: 1) Thus, modification of the centerline method allowed determination of both fractional shortening and wall thickening from echocardiographic images. Analysis by the criterion of
Low recurrence of syncope in patients with inducible sustained ventricular tachyarrhythmias treated with an implantable cardioverter-defibrillator.

Aims To determine the effectiveness of the implantable cardioverter defibrillator (ICD) in preventing recurrence of syncope in patients with structural heart disease, previously unexplained syncope and inducible ventricular arrhythmias. Methods Thirty-eight patients with syncope, structural heart disease and inducible arrhythmias had an ICD implanted. All ICDs delivered antitachycardia pacing and shocks of adjusted energy. Detection and therapy were programmed according to uniform criteria. Results The mean age of the patients was 63±11 years and most of them were male (36/38). After a mean follow-up of 28±15 (4–61) months, six patients died and one underwent heart transplantation. Syncope recurred in three patients, but in none of them was it caused by an arrhythmic event. In 18 patients, 113 episodes of ventricular tachycardia/ventricular fibrillation were detected and appropriately treated by the ICD. The mean time from implant until first appropriate therapy was 18±14 months. The actuarial probability of receiving appropriate therapy was 20% and 42% at 12 and 24 months, respectively. Conclusions In patients with unexplained syncope, structural heart disease and inducible arrhythmias, ICD prevents syncope associated with arrhythmic events. Frequent effective use of antitachycardia pacing and shocks of adjusted energy seem essential to this aim. Copyright 2002 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved .
Possible artificial introductions of freshwater peritrich ciliates and their implications for assessment of protistan biodiversity

The planktonic, sessiline peritrichs Epicarchesium pectinatum (Zacharias 1897) and Pelagovorticella natans (Faure-Fremiet 1924) were collected from different tributaries of the St. Lucie River, Florida. Epistylis procumbens Zacharias, 1897, another planktonic sessiline, was collected near the mouth of the Kissimmee River, Florida. Epicarchesium pectinatum and P. natans were not seen again in the St. Lucie drainage, probably because prolonged drought had increased the salinity of habitats drastically. Epistylis procumbens was absent from other, nearby sections of the Kissimmee River and nearby lakes and streams. Efforts to collect the three species from other bodies of water in Florida and from lakes and ponds in central New York met with no success; however, P. natans was found in two of the many localities sampled in North Carolina, an artificial pond and a natural lake. Pelagovorticella natans was found on only one of several visits to the latter locality. The three species occurred in habitats that were either within or near populated areas and had been extensively modified. This and the disjunct, ephemeral distributions of the peritrichs suggest that they may have been introduced artificially. Artificial introduction of ciliates or other protists is poorly documented but probable, considering their small size and consequent ease of transportation, and peritrichs should be especially suspect because many of them attach to aquatic plants. In the end, research on biodiversity of free-living protists must include the possibility of artificial introductions and develop methodologies to separate them from natural occurrences or else be reduced to a meaningless exercise.
Limitations of Thermal Infrared Imaging for Locating Neonatal Deer in Semiarid Shrub Communities

Neonate capture can be an important part of ungulate research. Systematic grid searching has been the most common method, but it is time consuming and usually requires a large number of people. A variety of methods have been used by wildlife professionals to capture ungulate neonates. We used a Raytheon PalmIR 250 Digital (Raytheon Commercial Infrared, Dallas, Texas) thermal infrared camera during the coolest time of night to search for deer (Odocoileus spp.) neonates in west-central Texas, USA. Using 2 methods (stationary observation and mobile searching), we detected one fawn and captured none. Efficacy of this technology at our study site may have been limited by the lack of a forest canopy and density of shrubs and herbaceous cover on our study site. Ground cover can obscure a bedded fawn, and direct sunlight on bed site habitat can result in false signals. We suggest wildlife professionals consider vegetation parameters, ungulate density, and road quality before purchasing expensive thermal imaging equipment.
Longitudinal Development of Speech Motor Control: Motor and Linguistic Factors

Lip shape in adult talkers is primarily driven by vertical opening; however, little is known about how children converge on this highly organized and efficient lip shape pattern. This longitudinal study investigated the development of lip shape control and its relation to speech and vocabulary acquisition in 28 typically developing children between 3 months and 5 years of age. Results suggested that during infancy lip shape was characterized by horizontal spreading of the lips, but that the contribution of vertical opening increased nonmonotonically over time. This change co-occurred with gains in expressive communication. These data suggest that lip shape may represent an important marker of normal oromotor development. Future work is required to determine the functional significance of the observed changes in lip shape control for identifying children at risk for speech and language impairments.
Cascaded optical parametric generation in reverse-proton-exchange lithium niobate waveguides

Cascaded optical parametric generation in lithium niobate waveguides involves simultaneous quasi-phase-matching of optical parametric generation and sum-frequency generation. We study details of this process in reverse-proton-exchange lithium niobate waveguides with quasi-phase-matching gratings from 6 to 42 mm in length. We identify the cascaded products in the time domain using a frequency-resolved cross correlator and study cascaded optical parametric generation under different levels of pump depletion. With phase-modulated gratings, we demonstrate control over the wavelength of the near-transform-limited signal pulses from cascaded optical parametric generation. With its low threshold and controllable temporal properties, cascaded optical parametric generation in reverse-proton-exchange waveguides can be a promising candidate for a tunable light source.
Inhibin at 90: from discovery to clinical application, a historical review.

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summar...
Effects of Androgens on Coronary Artery Atherosclerosis and Atherosclerosis-Related Impairment of Vascular Responsiveness

Abstract The factors responsible for the marked gender differences in risk of coronary heart disease and atherosclerosis severity remain largely undetermined. While some clinical and experimental evidence supports a protective effect of endogenous estrogen on the initiation and progression of atherosclerosis and incidence of coronary heart disease, much of the epidemiological data do not support this conclusion. The possibility that endogenous androgens may have adverse effects on atherosclerosis progression and coronary risk has received little attention. We investigated the effects of experimentally induced hyperandrogenism in female cynomolgus monkeys with diet-induced atherosclerosis. Animals were assigned randomly to one of four treatment groups: (1) untreated controls, (2) ovariectomized (sex hormone-deficient) controls, (3) treated with androstenedione and estrone (mild hyperandrogenism), or (4) treated with testosterone (male plasma androgen pattern). At necropsy, coronary atherosclerosis was approximately twice as extensive ( P <.05) in testosterone-treated animals relative to untreated controls, while treatment with androstenedione and estrone had no effect on atherosclerosis extent. Coronary plaque size was positively correlated with lumen size in intact and ovariectomized controls; however, there was no evidence of a similar relation between animals in either androgen treatment group. The atherogenic effects of testosterone were independent of variations in plasma lipoprotein and nonlipoprotein risk variables. Although chronic hyperandrogenism had adverse effects on atherosclerosis progression, it reversed ( P <.03) atherosclerosis-related impairment of endothelium-dependent vasodilator responses. We conclude that an experimentally induced male plasma androgen pattern results in exacerbation of diet-induced atherosclerosis and has potentially adverse effects on atherosclerosis-related arterial remodeling in female monkeys. The results indicate that testosterone may have a direct role in the increased rate of atherosclerosis progression and increased risk of coronary heart disease seen in men, relative to women, in most Western societies.
Existence of solution for impulsive hybrid differential equation

Purpose: Many problems in science and engineering can be modeled by nonlinear differential equations with initial conditions. The logistic equation is used widely in the study of population growth and decay. The logistic equation also has applications in ecology, statistics, medicine, chemistry, and physics, to name a few. Over time, the population growth or decay tends toward the stable equilibrium. However, in reality, some populations approach extinction or grow away from the equilibrium, and a new equilibrium will be formed. In addition, due to natural causes or unpredictable circumstances like explosions in an oil rig, hurricanes, or flooding at some time, t, the population will jump down or up in a small interval of time. These combined situations can be modeled as impulsive hybrid differential equations. In general, solutions to the nonlinear differential equations cannot be computed analytically. Methods: It is known that a fruitful method,which is both theoretical and computational, is the generalized monotone method with coupled lower and upper solutions. Furthermore, under uniqueness assumption, we proved the existence of a unique solution. Results: In this work, we extend the generalized monotone method with coupled upper and lower solutions to impulsive hybrid nonlinear differential equation.
Effects of processing and storage on the measurement of nitrogenous compounds in ovine blood

Four experiments were conducted to evaluate effects of processing and storage of sheep blood samples on measurements of ammonia N (AMN), urea N (URN), total protein (TP), albumin (ALB), total globulin (GLB), and the non-albumin non-globulin protein fraction (NAG). Experiment 1 compared the effects of using different anticoagulants. Blood samples (n = 15) were collected via jugular venipuncture into one of four evacuated tubes: no anticoagulant, serum; sodium heparin, plasma; sodium fluoride and potassium oxalate, plasma; tripotassium-ethylenediaminetetraacetic acid (EDTA), plasma. Anticoagulant affected (P < 0.0001) metabolite values, with TP, ALB, and GLB being higher in heparinized plasma, and URN, NAG, and AMN highest in serum. In addition, blood packed-cell volume was 12% and 15% higher (P < 0.0001) in samples collected in heparin and EDTA compared with samples collected in sodium fluoride and potassium oxalate. Experiment 2 investigated the effects of repetitive freezing and thawing (0–3 thaw cycles) of plasma samples (n = 15 blood samples collected in tubes containing sodium fluoride and potassium oxalate). Repetitive freezing and thawing decreased (P < 0.0001) URN and NAG by 21% and 54%, respectively, the latter as a result of a 4–13% increase (P < 0.0006) in ALB and GLB values. Experiment 3 evaluated the effects of storage length (0–26 weeks) and freezing temperatures (−20 °C vs. − 80 °C) on plasma samples (n = 16–20 blood samples collected in tubes containing sodium fluoride and potassium oxalate). All nitrogenous metabolites were affected by length of storage (P < 0.0001). Plasma AMN, URN, TP, and NAG were affected (0.0001 < P < 0.10) by storage temperature, and AMN, TP, GLB, and NAG measurements exhibited a temperature × day interaction (P < 0.05). In general, TP and NAG values declined with storage length, whereas URN, GLB, and AMN values increased. Plasma AMN increased 74% by Week 1 and 160% by Week 9, and samples stored at −20 °C were 14% higher than samples stored at −80 °C (P < 0.0001). Experiment 4 assessed the effects of storage of whole blood samples (n = 15 blood samples collected for serum) at 4 °C for 0–7 days. Serum URN and GLB decreased (P < 0.0001), and TP and AMN increased (0.0001 < P < 0.02) with increasing refrigeration time. Standardized analytical procedures must be followed to obtain reliable nitrogenous metabolite measurements.