cssi/SciSciGPT-SciSciNet huggingface dataset:
Chemistry in aqueous media

This chapter provides an overview of the main principles that explain the chemical behavior of natural and unnatural environmental processes occurring in aqueous media. Chemical interactions in aqueous systems make up an important area of environmental chemistry, and the properties of water determine the behavior observed in solution. The structure and density properties of water are largely determined by the hydrogen bonding of water molecules with one another. Density differences, along with wind effects, lead to ocean-current circulation patterns that are analogous to circulation in the atmosphere. Besides the unusual density properties that water exhibits as a result of hydrogen bonding, it also has high values for several thermodynamic properties such as specific heat and enthalpy of vaporization that are important factors in climate. In aqueous systems, water is the most abundant ligand. The behavior of elements present in large amounts in an aqueous system is controlled by the rules of solubility, acid-base equilibria, and complexation, but the behavior of trace substances is largely controlled by adsorption on solid surfaces. The chapter provides a discussion on several properties of water, such as solubility, acid-base behavior, pH and solubility of compounds, adsorption and ion exchange, and effects of temperature and pressure on equilibrium reactions.
Groups Interacting with Information and Communication Technology: A Temporal Perspective

Information and communication technology (ICT) alters the temporal conditions in which groups operate and transforms the way time is perceived, used, managed and disciplined in groups. A review of empirical research on groups interacting with ICT reveals that little research examines time per se as a variable of interest. This proposed research endeavors to examine (1) how the use of ICT is related to the temporal organization of groups’ daily events and tasks, (2) how groups temporally organize tasks and events with and by IT, and (3) how groups interpret and perceive the temporal dimension of their work. A case study on the use of ICT in three groups of IT professionals engaged in distributed work will be conducted. The research will deepen the theoretical understanding of intricacies between time and ICT in group settings, and offer practical guidelines for implementing and designing distributed work arrangements.
Gaucher's disease in pregnancy.

Abstract We have presented this case of Gaucher's disease complicating pregnancy because review of the available literature provides little guidance in the management of this problem. We feel that our experience with this case may be of some value in substantiating the belief that the prognosis for a successful outcome of pregnancy and delivery may be good, despite the presence of Gaucher's disease.
The pH dependence of red cell membrane transport of titratable anions studied by NMR spectroscopy.

Abstract The effects of varying extracellular pH on the rates of uptake of titratable anions by human erythrocytes under conditions of constant intracellular pH have been determined for a series of highly related anions, the phosphate "analogs." These compounds are simply substituted phosphorus oxyacids, differing in the number and acidity of titratable protons: phosphate (HPO4(2-), pKa 6.8); phosphite (HPO3(2-), pKa 6.4); hypophosphite (H2PO2-); methylphosphonate ((CH3)PO3(2-), pKa 7.4); dimethylphosphinate ((CH3)2PO2-); fluorophosphate [PO3F2-, pKa 4.7); and thiophosphate (HSPO3(2-), pKa 5.5). Suspensions of intact, Cl(-)-loaded erythrocytes (intracellular pH, 7.2) were incubated at 37 degrees C in isotonic buffers (pH 4-8) containing 60 mM phosphate analog for specified time intervals, whereupon influx was halted by the addition of 1 mM 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), an inhibitor of anion exchange. The intracellular anion concentrations were determined from 31P or 19F nuclear magnetic resonance spectra from the erythrocyte suspensions. The influx rates for the titratable phosphate analogs exhibited bimodal pH dependence, reaching maximal levels at pH values that increased with increasing anion pK. This pH-dependent behavior is consistent with a transport channel that contains a titratable regulatory site which interacts with the translocated anion. Based upon the Henderson-Hasselbalch equation, the probability that a titratable anion will have an electric charge of equal magnitude to that of the titratable carrier is highest at a pH value exactly midway between the pK of the regulatory site and that of the anion. The pH maxima observed for the phosphate analogs indicate a pK for this site of 5.5 at 37 degrees C. Intracellular pH changes associated with influx indicated that transport of the "fast" anion phosphite is largely in monoionized form. Intracellular pH changes associated with transport of slow anions were predominantly determined by partial ionic equilibrium effects and did not indicate the ionization state of the transported anion.
Tropospheric Ozone and Photochemical Smog

Ozone and particulates are two of the most important atmospheric pollutants in terms of human health. Elevated ozone was first associated with smog events in cities with heavy automobile traffic, especially Los Angeles. Elevated ozone and particulates also occur in multiday events over regions 2000 km or more in extent, including both urban and rural areas. These occur in densely populated industrialized regions of the United States, Europe, the Mediterranean, and (more recently) China. Ozone and particulates both have serious effects on human health, cause damage to agricultural crops, and affect climate. Formation of ozone and particulates involves chemical production from organics and nitrogen oxides in the presence of sunlight and warm temperatures. The process is significantly impacted by biogenic emission of organics, primarily from trees. In recent years, pollution controls have been partially successful in reducing ozone and particulate levels in the United States and Europe. This chapter describes the formation process for ozone and particulates, their relation to organics, nitrogen oxides, biogenic emissions, atmospheric dynamics and global cycles, impacts on health, agriculture, and climate.
New Tethyan Apiocrinitidae (Crinoidea, Articulata) from the Jurassic of Israel

A new species of Apiocrinites is described from the Middle Jurassic (Callovian) Matmor Formation of the Negev, Israel. Apiocrinites negevensis is from the tropical latitudes in the Tethys, in contrast to all other reported species of this genus. With a narrow radial facet and adjacent arms not in lateral contact and large aboral cup plates, A. negevensis is quite unusual for this genus.
Cooling for high heat flux VLSI systems

Recent projections have suggested that heat fluxes may possibly reach 100 W/cm/sup 2/ in future integrated circuit chips. The authors first discuss these projections and outline some of the problems associated with getting these power levels into high density packages for integrated systems. The authors then address the problem of getting the resulting heat back out of the package and look at the potential of liquid cooling including direct immersion and jet impingement. Recent results indicate that both modes of cooling will be highly useful in the cooling and packaging technology for the next generation of high performance computing systems. Finally, novel applications of micro-electronic fabrication processes to cooling high density multichip substrates and to fundamental heat transfer measurement are discussed. >
Development and integration of the aquarius scatterometer processor/control electronics for achieving high measurement accuracy

The upcoming Aquarius sea-surface salinity mission has tight requirements on backscatter measurement accuracy and stability at L-band frequencies (1.26 GHz). These requirements have driven the development of new capabilities in the radar's backend detector electronics, which are the focus of this paper. Topics include the development of flight-grade hardware aboard the scatterometer for radio frequency interference (RFI) detection and mitigation, and analog/digital electronics design techniques that reduce system noise and yield highly linear power detection over a wide dynamic range. We also summarize the approach taken to test the scatterometer's processing and control functions at the level of the integrated Aquarius flight instrument, and present some recent results from the integrated testing campaign.
Characterizing the impact of soft errors on iterative methods in scientific computing

The increase in on-chip transistor count facilitates achieving higher performance, but at the expense of higher susceptibility to soft errors. In this paper, we characterize the challenges posed by soft errors for large-scale applications representative of workloads on supercomputing systems. Such applications are typically based on the computational solution of partial differential equation models using either explicit or implicit methods. In both cases, the execution time of such applications is typically dominated by the time spent in their underlying sparse matrix vector multiplication kernel (SpMV, t ← A • y). We provide a theoretical analysis of the impact of a single soft error through its propagation by a sequence of sparse matrix vector multiplication operations. Our analysis indicates that a single soft error in some ith component of the vector y can corrupt the entire resultant vector in a relatively short sequence of SpMV operations. Additionally, the propagation pattern corresponds to the sparsity structure of the coefficient matrix A and the magnitude of the error grows non-linearly as(||Ai||2∗)k, after k SpMV operations, where, ||Ai∗||2 is the 2-norm of the ith row of A. We corroborate this analysis with empirical observations on a model heat equation using explicit method and well known sparse matrix systems (matrices from a test suite) for the implicit method using iterative solvers such as CG, PCG and SOR. Our results indicate that explicit schemes will suffer from soft error induced numerical instabilities, thus exacerbating intrinsic stability issues for such methods, that impose constraints on relative time and space step sizes. For implicit schemes, linear solver performance through widely used CG and PCG schemes, degrades by a factor as high as 200x, whereas, a stationary scheme such as SOR is inherently soft error resilient. Our results thus indicate the need for new approaches to achieve soft error resiliency in such methods and a critical evaluation of the tradeoffs among multiple metrics, including, performance, reliability and energy.
Around Closed Doors and Through Open Windows: A Theory of Aspirant Opportunism, 1796–2004

This article offers a theory of aspirant opportunism, which claims that presidential aspirants differ in their ability to perceive and capitalize on the electoral conditions and political events that occur during their political careers. As such, it asserts that political experience matters and specific types of political experiences matter more than others do. It presents several regression models (both linear and logistic), which more formally describe the effects of aspirant opportunism and political experience on the presidential campaigns from 1796 to 2004. The findings suggest that whereas exogenous events and electoral conditions, such as a poor economy or the presence of a war, help explain electoral success or failure, an aspirant's political experience and level of opportunism matter, but that they matter less now than they ever have before. This article concludes that the selection method and its biases over the course of its developmental history are important topics for scholars to consider a...
Structure and properties of ultralow density polyethylenes

Abstract With new advances in catalyst technology, polyethylenes of unprecedented lower densities are rapidly being introduced. Because these very low density polyethylenes offer very interesting mechanical properties, a systematic investigation into their thermal and mechanical properties has been made. It was found, for example, that despite the low densities achieved, wide compositional variations existed berween materials. A comparison was also made between the thermal and mechanical properties and the optical properties, with the conclusion that compositional homogeneities are required for good optical properties.
Solution of aerial triangulation problems using the N.R.C. analytical plotter

Abstract Combining the advantages of analog and analytical photogrammetric methods, the analytical plotter system is certainly the most flexible tool for the evaluation of diverse photogrammetric imagery, and at the same time an outstandingly powerful instrument in the field of aerial triangulation. The different techniques offered by this system for the accomplishment of aerial triangulation require corresponding formulations and solutions which, in turn, influence the design of appropriate programs. In this presentation, following a short description of the N.R.C. Analytical Plotter and its fundamental modes of operation, different solutions of aerial triangulation problems, concerning this system, are explained and discussed.
The role of PIWI and the miRNA machinery in Drosophila germline determination.

Summary Background The germ plasm has long been demonstrated to be necessary and sufficient for germline determination, with translational regulation playing a key role in the process. Beyond this, little is known about molecular activities underlying germline determination. Results We report the function of Drosophila PIWI, DICER-1, and dFMRP ( F ragile X M ental R etardation P rotein) in germline determination. PIWI is a maternal component of the polar granule, a germ-plasm-specific organelle essential for germline specification. Depleting maternal PIWI does not affect OSK or VASA expression or abdominal patterning but leads to failure in pole-plasm maintenance and primordial-germ-cell (PGC) formation, whereas doubling and tripling the maternal piwi dose increases OSK and VASA levels correspondingly and doubles and triples the number of PGCs, respectively. Moreover, PIWI forms a complex with dFMRP and DICER-1, but not with DICER-2, in polar-granule-enriched fractions. Depleting DICER-1, but not DICER-2, also leads to a severe pole-plasm defect and a reduced PGC number. These effects are also seen, albeit to a lesser extent, for dFMRP, another component of the miRISC complex. Conclusions Because DICER-1 is required for the miRNA pathway and DICER-2 is required for the siRNA pathway yet neither is required for the rasiRNA pathway, our data implicate a crucial role of the PIWI-mediated miRNA pathway in regulating the levels of OSK, VASA, and possibly other genes involved in germline determination in Drosophila .
Temporal factors influencing the pigeon's successive matching-to-sample performance: sample duration, intertrial interval, and retention interval.

Abstract A successive matching-to-sample procedure that entails the sequential presentation of sample and test stimuli and the monitoring of response rates in a go/no-go discrimination of matching and nonmatching stimuli was studied as an alternative to the familiar delayed-matching paradigm of animal short-term memory. Three within-subject experiments studied the effects of sample duration (1 to 12 seconds), intertrial interval (5 to 50 seconds), and retention interval (1 to 50 seconds) on the pigeon's successive-matching performance. The results revealed that retention was (a) an increasing function of sample duration and intertrial interval, and (b) a decreasing function of retention interval. These results were in accord with those of more traditional short-term memory paradigms, and reveal the suitability of the successive-matching procedure for studying memory processes.
Millimeter- and Submillimeter-Wave Spectra and Molecular Constants of LiF and LiCl

High-precision measurements of many millimeter- and submillimeter-wave rotational lines of different isotopic species of lithium fluoride and chloride in four different vibrational states have provided accurate evaluation of their rotational, vibrational, and potential constants. The resulting values are: ${B}_{e}=\frac{h}{8{\ensuremath{\pi}}^{2}\ensuremath{\mu}{{\mathcal{r}}_{e}}^{2}}$ is shown to differ from the observed value ${Y}_{01}$ because of small isotopic effects.
Cascading into focus

An adaptive immune pathway in bacteria and archaea is specified by clustered, regularly interspaced, short palindromic repeat (CRISPR) sequences ( 1 ). Research into CRISPR RNAs (crRNAs) and the CRISPR-associated (Cas) proteins have revealed the ability of most of these systems to target foreign DNA molecules for destruction. On pages 1473 and 1479 of this issue, Jackson et al. ( 2 ) and Mulepati et al. ( 3 ), respectively, and Zhao et al. ( 4 ) describe high-resolution structures of the multiprotein assembly called CRISPR-associated complex for antiviral defense (“Cascade”), which drives CRISPR interference in many strains of Escherichia coli. The structures show how Cascade presents crRNA to its DNA target, and demonstrate that DNA recognition occurs through a configuration that, surprisingly, is not double-helical.
Stretch-activated receptors mediate cardiac memory.

Background: Cardiac memory refers to long-lasting T-wave changes that follow an episode of altered ventricular activation sequence. Memory-induced alterations in repolarizing ion channel activity have been characterized. However, the mechanism by which changes in activation sequence produce these effects is unknown. We hypothesized that cardiac memory is mediated by the response of stretch-activated receptors (SARs) to a change in mechanical activation sequence. Methods: In anesthetized, closed-chest dogs, coronary sinus leads were used to pace the posterolateral left ventricle (LV) continuously for 1 hour at a rate of 120 bpm. The surface vectorcardiogram was used to quantify cardiac memory by measuring T-wave displacement after pacing. Streptomycin, which has been shown to block SARs, was given at a dose of 4 g intramuscularly 1 hour before experimental LV pacing sessions. T-wave displacement after control sessions of LV pacing in the absence of drug (n = 12) was compared to that produced by pacing after streptomycin administration (n = 10 sessions). Results: There was a distinct and consistent cardiac memory seen after 1 hour of LV pacing under control conditions, with T-wave displacement of 1.28 ± 0.43 mV (P < 0.001 vs baseline). Pretreatment with streptomycin had no direct effect on the electrocardiogram or hemodynamics, but decreased pacing-induced T-wave displacement to 0.50 ± 0.28 mV (P < 0.001 vs control sessions). Conclusions: Streptomycin, a SAR blocker, dramatically attenuated the development of cardiac memory following epicardial pacing. These data suggest that SARs are a critical link between mechanical sequence of activation and regional modulation of action potential duration that is responsible for cardiac memory.
The Mazur product map on Hardy-type sequence spaces

Abstract We study certain Hardy-type sequence spaces H p and H 0 p , 1 ⩽ p ⩽ ∞ , which are analogues of l ∞ and c 0 , respectively. We show that the Mazur product ⊠ : H 0 p × H q → c 0 is not onto for every p ∈ ( 1 , ∞ ) with q = p ( p − 1 ) −1 . We present corollaries for spaces defined via weighted l p seminorms and for c 0 . The latter corollary provides a new solution of Mazur's Problem 8 in the Scottish Book.
Intracerebral hemorrhage: Preventing recurrence of ICH-should statins be avoided?

Statin use in patients with cerebral hemorrhage may not be without risk. A recent article analyzing existing statin data in a mathematical model suggests that statins might need to be avoided after intracerebral hemorrhage, particularly in patients with a lobar hemorrhage.
Contact stresses in slabs due to round rough indenters

Abstract The method of point matching is used to find the contact stress distributions induced when elastic slabs are indented by rough, rigid, spherical and cylindrical indenters. Two methods are used. The Incremental Method considers loading as taking place in a number of stages. The Direct Method is based on the assumption that, for thick slabs, the radial displacement in the contact area is proportional to the square of the radius, and for thin slabs, it is proportional to the cube of the radius. While the Incremental Method is satisfactory for the whole range of a h (the ratio of contact length depth of slab), the Direct Method gives satisfactory results for thick and thin slabs in ranges of a h depending upon Poisson's ratio of the material of the slab.
Women in elite positions: Insiders or outsiders?

Formal institutional locations and informal participation in elite networks are examined for women and men occupying principal decision-making positions in powerful institutions in three advanced societies: the United States, West Germany, and Australia. In all three countries, the few women are concentrated in a small number of elite positions, especially those set aside for women. Social backgrounds vary, with women coming from somewhat higher status and class origins than their male counterparts. Further, network analyses reveal that men are more integrated than women in informal elite networks in all three nations. The results suggest that women in formal positions of power remain outsiders on the inside.
Regulated Association of Microtubule-associated Protein 2 (MAP2) with Src and Grb2: Evidence for MAP2 as a Scaffolding Protein

Microtubule-associated protein 2 (MAP2) and tau, which is involved in Alzheimer's disease, are major cytoskeletal proteins in neurons. These proteins are involved in microtubule assembly and stability. To further characterize MAP2, we took a strategy of identifying potential MAP2 binding partners. The low molecular weight MAP2c protein has 11 PXXP motifs that are conserved across species, and these PXXP motifs could be potential ligands for Src homology 3 (SH3) domains. We tested for MAP2 interaction with SH3 domain-containing proteins. All neuronal MAP2 isoforms bound specifically to the SH3 domains of c-Src and Grb2 in anin vitro glutathione S-transferase-SH3 pull-down assay. Interactions between endogenous proteins were confirmed by co-immunoprecipitation using brain lysate. All three proteins were also found co-expressed in neuronal cell bodies and dendrites. Surprisingly, the SH3 domain-binding site was mapped to the microtubule-binding domain that contains no PXXP motif. Src bound primarily the soluble, non-microtubule-associated MAP2c in vitro. This specific MAP2/SH3 domain interaction was inhibited by phosphorylation of MAP2c by the mitogen-activated protein kinase extracellular signal-regulated kinase 2 but not by protein kinase A. This phosphorylation-regulated association of MAP2 with proteins of intracellular signal transduction pathways suggests a possible link between cellular signaling and neuronal cytoskeleton, with MAP2 perhaps acting as a molecular scaffold upon which cytoskeleton-modifying proteins assemble and dissociate in response to neuronal activity.
Calculating the effective capacitance for the RC interconnect in VDSM technologies

In this paper, we present a new technique for calculating an effective capacitance of an RC interconnect line in very deep submicron design technologies. The calculation scheme guarantees that the effective capacitance model simultaneously matches both the 50% propagation delay and the 0-to-0.8 V/sub dd/ output transition behavior of a standard cell driving an RC interconnect. Experimental results show that the new technique exhibits high accuracy (less than 5% error) and high efficiency (converges in two or at most three iterations). The paper also includes extensions to handle complex cells as drivers of the RC interconnect.
A Hopf bifurcation for a reaction-diffusion equation with concentrated chemical kinetics☆

Abstract A reaction-diffusion equation related to some mathematical models of gasless combustion of solid fuel is studied. A formal bifurcation analysis by B. J. Matkowsky and G. I. Sivashinsky (SIAM J. Appl. Math. 35 (1978), 465–478) shows that solutions demonstrate behavior typical for the Hopf bifurcation. A rigorous treatment of this phenomenon is developed. The problem is considered as an evolution equation in a Banach space. To circumvent difficulties involving a possible resonance with the continuous spectrum, appropriate weighted norms are introduced. A suitable version of the Hopf bifurcation theorem is developed and the existence of time periodic solutions is proved for values of the parameter near some critical value.
The Meaning and Significance of the Transformation Problem: Two Contrasting Approaches

The "transformation problem" is at the heart of the Marxian labor theory of value. The topic has always been the subject of sharp controversy. The controvers 3" reflects not only the general ideological conflicts that surround all Marxist ideas, but also the disagreements among Marxists themselves about the nature of the labor theory of value. After defining some of Marx's terms, the paper describes two main schools of thought within the Marxian tradition, each having a verydifferent point of view on the nature and significance of value theory and the transformation problem. For Marx, a commodity is anything that is p roduced in order to be sold in the market. A commodity has both use value and value. A commodity's use value consists of its physical and chemical propert ies by virtue of which it can be put to certain human uses. These propert ies are independent of the historical peculiarities of the social context within which the commodity is produced (e.g., wheat has the same physical and chemical properties whether it is produced in a slave economy, a capitalist economy, or any other economy). A commodity's value, however, has no physical or chemical basis and is entirely the outcome of the specific historical and social circumstances in which it is produced. In all societies, in all times, product ion is a social process of interdependent producers, organized socially to undertake the physical and mental exertions necessary to transform their natural environment in order to make that environment sustain human, social life. This interdependency and the resultant necessity for social coordination of labor means that in all societies laboring, or producing, is both a set of activities and a set of social relations. Value is an aspect of a produced object that
New apparatus to reduce urinary drainage associated with urinary tract infections

Abstract The automatic release of povidone iodine (PVP-1) into the outlet tube of a urinary collecting bag significantly reduced urinary tract infections (UTIs) and provided a more practical bacterial barrier than manual instillation of PVP-I into the bag as used previously. In 52 patients using a new urinary drainage system with a cartridge that released PVP-I into the outlet tube of the collection bag UTIs developed in 3, compared with 57 patients using a standard closed drainage system and in whom 13 UTIs developed (p
Esterase in Imported Fire Ants, Solenopsis invicta and S. richteri (Hymenoptera: Formicidae): Activity, Kinetics and Variation

Solenopsis invicta and Solenopsis richteri are two closely related invasive ants native to South America. Despite their similarity in biology and behavior, S. invicta is a more successful invasive species. Toxic tolerance has been found to be important to the success of some invasive species. Esterases play a crucial role in toxic tolerance of insects. Hence, we hypothesized that the more invasive S. invicta would have a higher esterase activity than S. richteri. Esterase activities were measured for workers and male and female alates of both ant species using α-naphthyl acetate and β-naphthyl acetate as substrates. Esterase activities in S. invicta were always significantly higher than those in S. richteri supporting our hypothesis. In S. invicta, male alates had the highest esterase activities followed by workers then female alates for both substrates. In S. richetri, for α-naphthyl acetate, male alates had the highest activity followed by female alates then workers, while for β-naphthyl acetate, female alates had the highest activity followed by male alates then workers. For workers, S. richteri showed significantly higher levels of variation about the mean esterase activity than S. invicta. However, S. invicta showed significantly higher levels of variation in both female and male alates.
90 METABOLISM OF GUANINE ARABINOSIDE AND CYTOSINE ARABINOSIDE IN CELLS FROM PATIENTS WITH LEUKEMIA

Guanine arabinoside (araG) and cytosine arabinoside (araC) are nucleoside analogs which elicit cytotoxicity through their corresponding 5′-triphosphate, metabolites. Although less potent than araC, araG is of interest as an antileukemic agent due to its selective toxicity to cultured T compared to B lymphoblasts. In order to determine whether araG would exhibit a similar selectivity of action in vivo, we have examined the metabolism of this drug in mononuclear cells from patients with leukemia. Peripheral blood was diluted and incubated with 100 μM araG or 10 μM araC for 4 hours. The highest level of araGTP accumulation occurred in leukocytes from patients with T-cell ALL (median value 187 pmol/107 cells). Cells from patients with AML or non-T-, non-B cell. ALL accumulated lower levels of araGTP (72 and 86 pmol/107 cells, respectively), and cells from patients with CLL accumulated the lowest amount of araGTP (31 pmol/107 cells). In contrast, accumulation of araCTP was similar in cells from patients with T-cell ALL, AML and non-T, non-B-cell ALL. The amount of araG or araC remaining in plasma after 4 hours varied and was not related to the cellular accumulation of the corresponding nucleotides. These results suggest that araG may act as a selective chemotherapeutic agent in patients with T-cell ALL.
Structural Analysis of a Protective Epitope of the Francisella tularensis O-Polysaccharide

Francisella tularensis (Ft), the Gram-negative facultative intracellular bacterium that causes tularemia, is considered a biothreat because of its high infectivity and the high mortality rate of respiratory disease. The Ft lipopolysaccharide (Ft LPS) is thought to be a main protective antigen in mice and humans, and we have previously demonstrated the protective effect of the Ft LPS-specific monoclonal antibody Ab52 in a mouse model of respiratory tularemia. Immunochemical characterization has shown that the epitope recognized by Ab52 is contained within two internal repeat units of the O-polysaccharide [O-antigen (OAg)] of Ft LPS. To further localize the Ab52 epitope and understand the molecular interactions between the antibody and the saccharide, we determined the X-ray crystal structure of the Fab fragment of Ab52 and derived an antibody–antigen complex using molecular docking. The docked complex, refined through energy minimization, reveals an antigen binding site in the shape of a large canyon with ...
D-dimer and calf circumference in the evaluation of outpatient deep venous thrombosis

Abstract Objective: Duplex ultrasonography (DU) is the primary method for diagnosis of deep venous thrombosis (DVT) but is relatively expensive and not always readily available. Attempts to exclude the diagnosis of DVT with D-dimer or clinical criteria independently have been unsuccessful. The goal of our study was to evaluate a second-generation rapid quantitative D-dimer and simple clinical parameters for screening of outpatients for DVT. Patients and Methods: Patients undergoing DU of the lower extremities for suspected DVT were prospectively evaluated. Patients undergoing lower extremity venous ultrasound scan for suspected pulmonary embolism or already on anticoagulant therapy were excluded from the study. Data were analyzed to assess the optimal combination of characteristics to include and exclude proximal DVT. Results: One hundred fifty-six outpatients met inclusion criteria and were enrolled in the study. Elevated levels of D-dimer of 0.5 ng/mL or more were noted in 21 of 22 patients diagnosed with DVT, yielding a sensitivity of 95% and negative predictive value of 99%. Subjective symptoms of swelling or pain were present in 94% of all outpatients. Asymmetric calf swelling of more than 2.0 cm was noted in 14 of 22 patients (64%) with proximal DVT compared with 22 of 134 patients (16%) without DVT ( P Conclusion: A combination of a second-generation quantitative D-dimer and calf measurement provides an easy and effective means of excluding proximal DVT when screening outpatients. Patients with calf circumference 2.0 cm or less and a negative D-dimer may undergo nonemergent DU. Patients with a positive D-dimer or asymmetrical calf swelling of more than 2.0 cm alone or in combination should undergo emergent DU. (J Vasc Surg 2002;36:877-80.)
Variability of target and normal structure delineation using multimodality imaging for radiation therapy of pancreatic cancer.

Summary This work explores the potential of using various magnetic resonance imaging, positron emission tomography, and computed tomography techniques to define treatment targets and organs at risk for radiation therapy of pancreatic cancer. Significant differences exist in the gross tumor volumes defined by these imaging modalities and sequences. Further studies are required to establish reliable imaging modalities and/or techniques for the accurate target delineation, which will be crucial particularly in dose escalation and/or dose painting for pancreatic cancer. Purpose: To explore the potential of multimodality imaging (dynamic contrast eenhanced magnetic resonance imaging [DCE-MRI], apparent diffusion-coefficient diffusion-weighted imaging [ADC-DWI], fluorodeoxyglucose positron emission tomography [FDG-PET], and computed tomography) to define the gross tumor volume (GTV) and organs at risk in radiation therapy planning for pancreatic cancer. Delineated volumetric changes of DCE-MRI, ADC-DWI, and FDG-PET were assessed in comparison with the finding on 3-dimensional/4-dimensional CT with and without intravenous contrast, and with pathology specimens for resectable and borderline resectable cases of pancreatic cancer. Methods and Materials: We studied a total of 19 representative patients, whose DCE-MRI, ADC-DWI, and FDG-PET data were reviewed. Gross tumor volume and tumor burden/active region inside pancreatic head/neck or body were delineated on MRI (denoted GTVDCE ,a nd GTVADC), a standardized uptake value (SUV) of 2.5, 40%SUVmax, and 50%SUVmax on FDG-PET (GTV2.5, GTV40% ,a nd GTV50%). Volumes of the pancreas, duodenum, stomach, liver, and kidneys were contoured according to CT (VCT), T1-weighted MRI (VT1), and T2-weighted MRI (VT2 )f or 7p atients. Results: Significant statistical differences were found between the GTVs from DCEMRI, ADC-DW, and FDG-PET, with a mean and range of 4.73 (1.00-9.79), 14.52 (3.21-25.49), 22.04 (1.00-45.69), 19.10 (4.84-45.59), and 9.80 (0.32-35.21) cm 3 for GTVDCE ,G TV ADC ,G TV2.5, GTV 40% ,a nd GTV 50%, respectively. The mean difference and range in the measurements of maximum dimension of tumor on DCE-MRI, ADC-DW, SUV2.5, 40%SUVmax, and 50%SUVmax compared with pathologic specimens were � 0.84 (� 2.24 to 0.9), 0.41 (� 0.15 to 2.3), 0.58 (� 1.41 to 3.69), 0.66 (� 0.67 to 1.32), and 0.15 (� 1.53 to 2.38) cm, respectively.
β-blockers and Reduction of Cardiac Events in Noncardiac Surgery: Scientific Review

Recent studies suggest that -blockers administered perioperatively may reduce the risk of adverse cardiac events and mortality in patients who have cardiac risk factors and undergo major noncardiac surgery. The objective of this article is to provide practicing physicians with examples of perioperative -blocker use in practice by using several hypothetical cases. Although current evidence describing the effectiveness of perioperative -blockade may not address all possible clinical situations, it is possible to formulate an evidence-based approach that will maximize benefit to patients. We describe how information from several sources can be used to guide management of patients with limited exercise tolerance, those at highest risk for perioperative cardiac events, patients who are taking -blockers long-term, and those with relative contraindications to -blockade. Even though fine points of their use remain to be elucidated, perioperative -blocker use is important and can be easily applied in practice by any physician involved with the care of patients perioperatively.
Pathogenic RNA repeats: an expanding role in genetic disease

Fragile X mental retardation and Friedreich's ataxia were among the first pathogenic trinucleotide repeat disorders to be described in which noncoding repeat expansions interfere with gene expression and cause a loss of protein production. Invoking a similar loss-of-function hypothesis for the CTG expansion causing myotonic dystrophy type 1 (DM1) located in the 3' noncoding portion of a kinase gene was more difficult because DM is a dominantly inherited multisystemic disorder in which the second copy of the gene is unaffected. However, the discovery that a transcribed but untranslated CCTG expansion causes myotonic dystrophy type 2 (DM2), along with other discoveries on DM1 and DM2 pathogenesis, indicate that the CTG and CCTG expansions are pathogenic at the RNA level. This review will detail recent developments on the molecular mechanisms of RNA pathogenesis in DM, and the growing number of expansion disorders that might involve similar pathogenic RNA mechanisms.
Properties and subcellular distribution of enzymes required for acetoacetate biosynthesis in chicken liver.

Abstract 1. 1. Evidence is presented which indicates that the rate-limiting enzyme of the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) pathway of acetoacetate synthesis in chicken liver is HMG-CoA synthase as it is in other species. 2. 2. Maximum rates of acetoacetate synthesis in the catalytic assay system, in which acetyl-CoA is generated from acetyl phosphate and coenzyme A in the presence of purified phosphotransacetylase, was observed when the reaction mixture contained 1 mM coenzyme A and was supplemented with equimolar amounts of both Mg 2+ and Mn 2+ . 3. 3. On the basis of studies on the subcellular distribution of HMG-CoA synthase and the other enzymes involved, it is estimated that acetoacetate synthesis capacity is about evenly divided between mitochondrial and cytoplasmic fractions.
Mixed-mode fracture of a lubricated interface

Abstract The fracture of an interface containing a liquid was investigated under nominally mixed-mode conditions. The experiments were designed to be a study of a model interface for which frictional effects are minimised. Alternatively, the system could be considered to provide an analogy for an interface along which there is little resistance to shear. The fracture resistance was found to be independent of the nominal phase angle, and it was in excellent agreement with the interfacial surface energy determined by a capillary-rise experiment. Furthermore, the study emphasised the importance of the difference between a nominal phase angle determined from macroscopic considerations and the local phase angle appropriate for the crack-tip region.
Mapping the composition of planetary surfaces by Auger electron spectroscopy

We explore the feasibility of Auger electron spectroscopy as a remote sensing technique to map the composition of the sunlit surfaces of planetary bodies without atmospheres. Solar x rays eject photoelectrons from the planetary surface. The resulting ions relax by emission of fluorescence x rays or Auger electrons, with energies characteristic of the element which is ionized. The spectrum of Auger electrons and photoelectrons is computed for a variety of elements and for representative lunar rock types illuminated by soft x‐ray line and continuum emission typical of solar long‐lived coronal active regions. The Auger electron lines for O, Si, Mg, Al, Fe, and Ca in lunar rocks stand well above the continuum background from photoelectrons and backscattered interplanetary electrons, with typical line‐to‐continuum ratios of ∼20 to ≳103. An ideal Auger electron spectroscopy instrument to map the elemental composition of planetary surfaces should have a combination of high energy resolution (≲2 eV) and large geometric factor (≳0.1 cm2 sr). This technique could be applied to the Moon, Mercury, asteroids, comets, and perhaps the moons of outer planets.
Developmental regulation of human β-globin gene transcription: a switch of loyalties?

Synthesis of different hemoglobin polypeptides during the early stages of human development is principally regulated by transcriptional control mechanisms that determine which of the five beta-type globin genes is expressed. The means by which this is achieved have been scrutinized for several decades, and insights have been gained from introducing segments of the human beta-globin locus into transgenic mice, and from analysis of naturally occurring mutations at the locus. I describe here a model which attempts to resolve several of the current puzzles and provides simple, testable predictions for how differential beta-globin gene transcription might be achieved during human development.
Effects of dobutamine on Gorlin and continuity equation valve areas and valve resistance in valvular aortic stenosis

Abstract Previous studies demonstrated changes in aortic valve area calculated by the Gorlin equation under conditions of varying transvalvular flow in patients with valvular aortic stenosis (AS). To distinguish between flow-dependence of the Gorlin formula and changes in actual orifice area, the Gorlin valve area and 2 other measures of severity of AS, continuity equation valve area and valve resistance, were calculated under 2 flow conditions in 12 patients with AS. Transvalvular flow rate was varied by administration of dobutamine. During dobutamine infusion, right atrial and left ventricular end-diastolic pressures decreased, left ventricular peak systolic pressure and stroke volume increased, and systolic arterial pressure did not change. Heart rate increased by 19%, cardiac output by 38% and mean aortic valve gradient by 25%. The Gorlin valve area increased in all 12 patients by 0.03 to 0.30 cm2. The average Gorlin valve area increased from 0.67 ± 0.05 to 0.79 ± 0.06 cm2 (p
The Strength Analysis of Wooden Bends

An analytical method is presented for calculating the strengths of bends made of solid wood. The analysis is based on a finite element method of solution for the stress field, and on appropriate failure criteria adopted from the theory of composite materials.
Applying Radiation Hardening by Software to Fast Lossless compression prediction on FPGAs

As scientists endeavor to learn more about the world's ecosystems, engineers are pushed to develop more sophisticated instruments. With these advancements comes an increase in the amount of data generated. For satellite based instruments the additional data requires sufficient bandwidth be available to transmit the data. Alternatively, compression algorithms can be employed to reduce the bandwidth requirements. This work is motivated by the proposed HyspIRI mission, which includes two imaging spectrometers measuring from visible to short wave infrared (VSWIR) and thermal infrared (TIR) that saturate the projected bandwidth allocations. We present a novel investigation into the capability of using FPGAs integrated with embedded PowerPC processors to adequately perform the predictor function of the Fast Lossless (FL) compression algorithm for multispectral and hyperspectral imagery. Furthermore, our design includes a multi-PowerPC implementation which incorporates recently developed Radiation Hardening by Software (RHBSW) techniques to provide software-based fault tolerance to commercial FPGA devices. Our results show low performance overhead (4–8%) while achieving a speedup of 1.97× when utilizing both PowerPCs. Finally, the evaluation of the proposed system includes resource utilization, performance metrics, and an analysis of the vulnerability to Single Event Upsets (SEU) through the use of a hardware based fault injector.
Characterization of an islet-activating protein-sensitive site in mouse sperm that is involved in the zona pellucida-induced acrosome reaction.

Abstract Recently, it has been suggested that a mouse sperm-associated protein with properties similar to the inhibitory guanine nucleotide-binding regulatory protein Gi plays an intermediary role in the zona pellucida-induced acrosome reaction (Endo, Y., Lee, M. A., and Kopf, G. S. 1987. Dev. Biol. 119, 210–216). In the present study experiments were designed to characterize further the role of this Gi-like protein in mediating this physiological event. Sperm capacitated in the presence of islet-activating protein (IAP) were inhibited from undergoing the acrosome reaction induced by either solubilized zonae pellucidae or purified ZP3. This inhibitory effect was observed with IAP concentrations previously shown to ADP-ribosylate the α-subunit of the Gi-like protein and inhibit the acrosome reaction induced by mechanically isolated, structurally intact zonae pellucidae. Inhibition occurred as a consequence of the inability of the sperm to progress from a capacitated, acrosome-intact state (B pattern) to an intermediate stage prior to the completion of the acrosome reaction (S pattern), as assessed with a chlortetracycline fluorescence assay. These inhibitory effects of IAP on the sperm acrosome reaction were confirmed by electron microscopy. In contrast, the acrosome reaction induced either spontaneously or nonspecifically by A-23187 was completely insensitive to IAP. Since the inhibitory effects of IAP on the acrosome reaction were at the level of the B to S transition, a transition normally accompanied by a loss in a transmembrane pH gradient, the effects of IAP on the loss of this gradient was assessed with the pH-sensitive fluorescent probe, 9-amino-3-chloro-7-methoxyacridine. The IAP-induced inhibition of the B to S transition was accompanied by a parallel retention of the transmembrane pH gradient. 3-Quinuclidinyl benzilate (QNB), a muscarinic cholinergic antagonist which has been demonstrated to specifically inhibit the zona-induced acrosome reaction at the B to S transition, also prevented the loss of this transmembrane pH gradient. The similarity of the effects of both IAP and QNB on sperm-zona interactions suggested that the IAP- and QNB-sensitive sites were either closely related or identical. Experiments designed to test these possibilities suggested that both sites were not identical. Finally, it was demonstrated that the acceleration of the zona-induced B to S transition observed with biologically active phorbol esters was insensitive to IAP, suggesting that the site of phorbol ester action is downstream from or independent of the IAP-sensitive site. These studies demonstrate that the mouse sperm Gi-like protein appears to mediate the acrosome reaction induced only by a physiologically relevant ligand (e.g., ZP3) and that this protein may functionally couple membrane-associated events with intracellular signaling systems.
Finite Difference Modeling of Anisotropic Flows

A modification to the finite difference equations is proposed in modeling multidimensional flows in an anisotropic material. The method is compared to the control volume version of the Taylor expansion and the finite element formulation derived from the Galerkin weak statement. For the same number of nodes, the proposed finite difference formulation approaches the accuracy of the finite element method. For the two-dimensional case, the effect on accuracy and solution stability is approximately the same as quadrupling the number of nodes for the Taylor expansion with only a proportionately small increase in the number of computations. Excellent comparisons are made with a new limiting case exact solution modeling anisotropic heat conduction and a transient, anisotropic conduction experiment from the literature.