cssi/SciSciGPT-SciSciNet huggingface dataset:
Microstructure and Compression Deformation Behavior in the Quasicrystal-Reinforced Mg-6Zn-2Y Alloy Solidified under Super-High Pressure at Room-Temperature

The microstructures of the Mg-6Zn-2Y alloy solidified under high pressures were investigated using scanning electronic microscopy (SEM) and X-ray diffraction (XRD). The room-temperature compression behavior was analyzed through experiments, showing that the microstructures of the alloys are consisted of α-Mg and quasicrystal I-Mg3Zn6Y phases. With solidification pressure increasing, the microstructures were refined, and the morphologies of the inter-dendritic secondary phase were improved from continuous networks into long-island and granule. The compression strength, yielding strength and compressibility were increased significantly corresponding with solidification pressure, from 259.02 MPa, 230.39 MPa and 18.3% under ambient pressure to 361.43 MPa, 272.25 MPa and 33.1% under high pressure of 6 GPa. The cleavage planes are flat, and the cleavage steps are straight under ambient pressure. However, the cleavage planes are small and rough under 4-6 GPa; tearing dimples occur in the tearing area, indicating that the degree of cleavage fracture decreases under high pressure.
Anemia is associated with brain tissue hypoxia and metabolic crisis after severe brain injury

After severe brain injury, anemia can adversely affect cerebral oxygen delivery and brain tissue oxygen (PbtO2). However, it is unclear whether low hemoglobin (Hb) contributes to brain tissue hypoxia or compromises oxidative metabolism.
Large-eddy Simulation of Motored Flow in a Two-valve Piston Engine: POD Analysis and Cycle-to-cycle Variations

Large-eddy simulation (LES) has been performed for a single-cylinder, two-valve, four-stroke-cycle piston engine through 70 consecutive motored cycles. Initial comparisons of ensemble-averaged velocity fields have been made between LES and experiment, and proper orthogonal decomposition (POD) has been used to analyze the complex in-cylinder turbulent flows. Convergence of POD modes has been quantified, several POD variants have been explored, and sensitivity of results to analyzing different subsets of engine cycles has been studied. In general, it has been found that conclusions that were drawn earlier from POD analysis of a simplified non-compressing piston-cylinder assembly with a fixed valve carry over to the much more complex flow in this motored four-stroke-cycle engine. For the cases that have been examined, the first POD mode essentially corresponds to the ensemble-averaged mean velocity. The number of engine cycles required to extract converged POD modes increases with mode number, and varies with phase (piston position). There is little change in the lower-order phase-invariant POD modes when as few as 24 phases per cycle (30° between samples) are used, and complex 3-D time-dependent in-cylinder velocity fields through full engine cycles can be reconstructed using a relatively small number of POD modes. Quantification of cycle-to-cycle variations and insight into in-cylinder flow dynamics can be extracted through analysis of phase-invariant POD modes and coefficients.
Size-dependent competition in a gregarious porcelain crab Petrolisthes cinctipes (Anomura: Porcellanidae)

Studies of competition in benthic marine organisms have focused on sessile filter-feed- ers and mobile grazers, to the neglect of mobile filter-feeders, including porcelain crabs. The present study demonstrates intraspecific competition in Petrolisthes cinctipes (Randall) (Porcellanidae: Anomura). P. cinctipes settles gregariously and lives in high-density, multi-size aggregations. Studies of gregarious species often identify the benefits of aggregation without quantifying the concomitant costs; this study quantifies these costs. In field and laboratory experiments, P. cinctipes growth rates declined with increasing conspecific density and this decline was more severe for smaller individuals. P. cinctipes also fed less frequently at high density, and this effect was more pronounced for smaller individuals. This indicates that size-dependent agonistic interactions in P. cinctipes have effects on feeding rate and, ultimately, on growth rate. Resource levels were manipulated in laboratory experi- ments by using filtered and unfiltered seawater. The effect of resource level also depended on size: smaller crabs were more sensitive to changes in food level. Thus, conspecific density and food avail- ability both affected growth rate in a size-dependent manner. Therefore, the costs of aggregation are more extreme for recruits than for adult crabs; recruits suffer more from competition, but may also benefit more if conspecific cueing results in settlement to sites with higher food availability.
Reviewing the SIGCSE reviewing process

The ACM Special Interest Group in Computer Science Education (SIGCSE) has long used a double-blind reviewing process for both its annual symposium and ITiCSE conference. However, it is healthy for a community to review its policies and practices periodically to ensure that they continue to meet the needs and objectives of the community. Toward this end, this paper suggests a set of general goals for the SIGCSE reviewing process, identifies a number of important issues, and presents suggestions for resolving these issues.
Metasearch in the Users' Context

The article describes the inner workings of metasearch and makes the case that there are many opportunities to improve this technology. Metasearch can be improved by focusing on the user's search context. Examples of this are provided by the University of Rochester River Campus Libraries (UR) development of a UR metasearch interface. The benefits of identifying and addressing stakeholder interests to overcome obstacles with moving the technology forward are explored. A specific framework and a mechanism to allow automatic database selection for metasearch users are presented.
Hereditary retinal dystrophy in the rat: rhodopsin, retinol, vitamin A deficiency.

Abstract Measurements were performed on young hooded (B) and albino (Ba) rats with inherited visual cell degeneration of the Bourne-Campbell-Tansley type, in comparison to heterozygotes. The animals were reared and maintained in a dark environment. Rhodopsin of the dark-maintained B and Ba increased between 16 and 35 days to levels twice those of controls. These high levels were maintained up to the age of 100 days. Estimates indicate that no more than 50% of the rhodopsin is contained in surviving visual cells at the age of 25 days, only 25% at 35 days and virtually none at 80 days. The transfer of retinol from bleached rhodopsin to the pigment epithelium (Pe) is increasingly slowed from 17 days on as a function of the accumulation of debris. The conversion of retinal from bleached rhodopsin to retinol also occurs at a lower rate; about 45% of the retinal is converted to retinol at the end of a 10-min period of light exposure in 37-day-old Ba compared to 80% in the controls. The rate of rhodopsin regeneration after 1 hr exposure to strongly bleaching light is decreased after the age of 17 days; it is only about 30% normal for 6 hr in darkness at 37 days. Maintenance on a vitamin A deficient diet accelerates the rate of visual cell death and ERG decline as early as 12 days after withholding vitamin A from weaned B rats.
Tobacco, alcohol, and marijuana use among first-year U.S. college students: a time series analysis.

The present study sought to evaluate the day-to-day patterns of tobacco, alcohol, and marijuana use among first-year college students in the United States. Using 210 days of weekly time-line follow-back diary data collected in 2002 to 2003, the authors examined within-person patterns of use. The sample was 48% female and 90% Caucasian. Sixty-eight percent of the participants were permanent residents of Indiana. Univariate time series analysis was employed to evaluate behavioral trends for each substance across the academic year and to determine the predictive value of day-to-day substance use. Some of the most common trends included higher levels of substance use at the beginning or end of the academic year. Use on any given day could be predicted best from the amount of corresponding substance use 1 day prior. Conclusions: Although universal intervention might best be focused in the earliest weeks on campus and at the end of the year when substance use is at its highest, the diversity of substance use tr...
Economics and technological change: An evolutionary epistemological inquiry

The failure of neoclassical economic theories to explain the nature and significance of the phenomenon of technological change is critically looked at in this article. Although there are numerous excellent works in the literature on technological change that criticize the inadequacy of neoclassical economists’ approach to this phenomenon, my objective, however, is to open a new discourse on technological change by emphasizing the epistemological significance of technology. It is argued that the concept of technology as essentially a process of knowledge created for doing things and solving problems, and technological change as essentially a process of knowledge change occurring within the contexts of the political economic and social constructivist frameworks that inform the dynamics of this essentially qualitative process can address this failure. Empirically based analytical methodologies may be able to measure the impact of technological change, an evolutionary epistemology of technological change may be better equipped to understand and explain this phenomenon.
Thiiranium ion intermediates in the formation and reactions of S-(2-haloethyl)-l-cysteines

Abstract Thiiranium ions formed from the cysteine or glutathione conjugates of 1,2-dihaloethanes are believed to be responsible for the genotoxicity of the parent alkyl halides. The conversions of specifically deuterated β-hydroxyethyl sulfides to the corresponding β-haloethyl sulfides are studied to provide direct evidence for the involvement of thiiranium ions in the reactions of the cysteine conjugates of 1,2-dihaloethanes. S-(2-Hydroxyethyl-1, 1-d2)- l -cysteine is converted to an equal mixture of the 1,1-d2 and 2,2-d2 isomers of the corresponding S-(2-haloethyl)- l -cysteines in concentrated hydrochloric, hydrobromic, or hydroiodic acids without detectable formation of the 2,2-d2 isomer of the parent hydroxyethyl derivative. Dissolution of S-(2-hydroxyethyl)- l -cysteine in trifluoromethanesulfonic acid yields a compound with the NMR spectral properties of S-( l -cysteinyl)ethyl thiiranium trifluoromethanesulfonate. The organosoluble S-(2-hydroxyethyl-1,1-d2) benzyl sulfide is converted to an equal mixture of the 1,1-d2 and 2,2-d2 isomers of S-(2-chloroethyl) benzyl sulfide by thionyl chloride or triphenylphosphine: carbon tetrachloride. These results demonstrate the involvement of thiiranium ion intermediates in the conversion of 2-hydroxyethyl sulfides to 2-haloethyl sulfides in halogen acids and a similar symmetrical intermediate in the chlorination reactions effected by thionyl chloride or triphenylphosphine: carbon tetrachloride.
Determinants of Women's Entry into Self–Employment

Objective. Building on recent studies that have shown how employment– and family–related characteristics are uniquely intertwined in facilitating women's decisions to work for themselves, I examine the process of transitions into self–employment among white, African–American, and Hispanic women. Methods. This study analyzes data from the National Longitudinal Survey of Youth, a national probability sample of those born between 1957 and 1964, which allows me to apply a dynamic model for studying women's employment transitions. Results. Regardless of race or ethnicity, factors such as work experience and the presence of a spouse encourage women to become self–employed. At the same time, the distributions of these characteristics for African–American women, and to a lesser extent Latinas as well, significantly account for their slower entry into self–employment. The effect of children on women's entry into self–employment, which earlier studies often found to be positive, especially among whites, is mixed. Conclusions. These findings reveal significant racial/ethnic differences in the process of female self–employment and also call into question the view that self–employment allows working mothers to better combine their careers with family responsibilities than does wage/salary sector employment.
Pulse Electrophoresis of Muscle Myosin Heavy Chains in Sodium Dodecyl Sulfate–Polyacrylamide Gels

Abstract We have developed a new method that provides enhanced resolution of myosin heavy chain (MHC) isoforms by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). The key feature of this protocol involves the application of current to slab SDS gels in a pulsatile, repetitive manner rather than continuously as in standard gel systems. This protocol, designated pulse electrophoresis, was achieved by means of a device that intermittently gates the output of a conventional power supply. When used in long (32 cm) separating gels, pulse electrophoresis not only significantly improves the resolution of MHC isoforms compared to conventional systems, but also reduces common artifacts associated with long running times, such as blurred bands and comingling of closely spaced bands. In addition to the increased resolution of protein bands, pulse electrophoresis also allows detection of bands corresponding to previously unidentified MHC isoforms in mammalian and avian tissue. In rat myocardium, for example, pulse electrophoresis revealed three MHC isoform bands, two of which appeared to correspond to two alpha-MHC subspecies. Alternative splicing of the rat alpha-MHC gene is known to generate two isoform species differing by inclusion (or exclusion) of a single glutamine residue, whose relative levels of expression correspond nicely with the amounts of each band identified in this study. Therefore, we cannot rule out that the system presented here may be sufficiently sensitive to differentiate between high molecular weight proteins differing in a single amino acid.
Collinsonites schopfii gen. et sp. nov., a herbaceous lycopsid from the Upper Permian of Antarctica

A new lycopsid morphotaxon, Collinsonites schopfii gen. et sp. nov., is described from an Upper Permian deposit on Mount Achernar, in the central Transantarctic Mountains, Antarctica. The species is represented by numerous fragments of slender dichotomizing stems. Leaves are <5 mm long, eligulate and arranged in a low spiral. One stem bears leaves with 12–16 delicate spines at the lateral margins. Collinsonites stems represent the first illustrated macrofossil evidence for the presence of herbaceous lycopsids in the Permian of Antarctica.
Recidivism and Social Interactions

Using a national sample, this article identifies the risk factors for recidivism among female, male, black, white, and Hispanic felony probationers. The individual hazard function is assumed to depend on individual and neighborhood characteristics, as well as on social interactions among probationers. In selecting the covariates from a set of potential candidates, Bayesian model averaging is used to account for both model uncertainty and the subsequent inference. The results point to social interactions as one of the most significant factors affecting recidivism among all gender, ethnicity, and race groups. When a frailty parameter is added to account for the possibility of unobserved risk factors shared by probationers within neighborhoods, the empirical results remain robust indicating negligible unobserved neighborhood-level heterogeneity.
Interfacial tensions of n-hexane with aqueous solutions of sodium dodecyl sulfonate in equilibrium with dimethyl ether at elevated pressures

Abstract The interfacial tensions of n -hexane with water and aqueous solutions of sodium dodecyl sulfonate are found to be very sensitive to the presence of dissolved dimethyl ether. Values for the interfacial tension, γ o/w , have been determined as a function of pressure by means of the pendant drop method. The change in interfacial tension of hexane against water and aqueous solutions of sodium dodecyl sulfonate induced by dissolved dimethyl ether is found to have a similar pressure dependence to that found previously for water and solutions of this same surfactant in direct contact with gaseous dimethyl ether. It is found that sodium dodecyl sulfonate and dissolved dimethyl ether both serve to lower the interfacial tension between hexane and the aqueous phase. However, their individual contributions are not additive but rather reflect a competition between the mildly surface-active ether molecules and dodecyl sulfonate anions for available area at the oil—water interface.
Where is the start line

In this issue of Blood , Mielcarek and colleagues report on the results of a retrospective analysis of the outcomes of initial acute GVHD therapy.
Rib fracture fixation for flail chest: what is the benefit?

Background Recently, rib fracture fixation for flail chest has been used increasingly at both academic and nonacademic trauma centers. Although a few small non-US studies have demonstrated a clinical benefit, it is unclear whether this benefit outweighs the added expense and potential perioperative complications related to the procedure. We therefore sought to determine if open reduction and internal fixation of ribs for flail chest (ORIF-FC) represents a cost-effective means for managing these patients. Study Design A Markov transition state analysis was performed modeling the outcomes of the standard of care or ORIF-FC for flail chest. The incidences of ventilator-associated pneumonia, tracheostomy, sepsis, prolonged ventilation, deep vein thrombosis, pulmonary embolism, wound infection, and postoperative hemorrhage were obtained based on literature review. Medicare 2010 reimbursement costs were used for diagnoses and procedures. A quality of life improvement factor ranging from 0 to 15% improvement was used to estimate the improvement in pain and functional outcomes related to ORIF-FC. The most cost-effective treatment was then determined, ranging the incidences of ventilator-associated pneumonia and quality of life improvement factor. Results Cost effectiveness was $15,269 for ORIF-FC compared with $16,810 for standard of care. Even when the quality of life improvement factor was set to 0%, ORIF-FC remained the most cost-effective strategy. Similarly, ORIF-FC remained the most cost-effective strategy by $8,400 when the incidence of ventilator-associated pneumonia after ORIF was as high as 22%. Conclusions Despite the additional cost of surgery, rib fracture fixation dominates the standard of care and should be considered in the management of appropriate flail chest patients.
Feedbacks, thresholds and synergies in global change: population as a dynamic factor

The role of feedbacks, thresholds, and synergies in environmental science, and their implications for environmental degradation under a growing human population, are reviewed. A detailed analysis of the impacts of climate change on water resources is used to elucidate mechanisms by which nonlinearities arise in environmental science. Additional examples are drawn from analysis of soil degradation and non-climate related degradation of water resources. The often-assumed notion that impacts will grow in proportion to population size is shown to be overly optimistic. In particular, feedbacks, thresholds, and synergies among multiple threats, tend to amplify risk and cause environmental impacts to grow considerably faster than linearly in population size, even when the per-capita living standard and the technological systems deployed to achieve that living standard are assumed to remain constant.
Covariance Ration Analysis of Molecular Dynamics Trajectories of Hiv-1 Reverse Transcriptase

HIV-1 reverse transcriptase (RT) is a major drug target for HIV treatment, and understanding its function and inhibition would significantly improve our ability to create new anti-HIV drugs. RT can perform DNA-polymerization from either a DNA or an RNA template, and possesses an RNase function. Elastic network modeling is a method to rapidly probe and compare protein dynamics. We have previously shown that combining elastic network modeling with hierarchical clustering of both structural and dynamics data elucidates RT functional states. Here we extend our method beyond X-ray crystallographic structural data, to structural data determined by short molecular dynamics trajectories of RT bound to a primer template and either the correct dNTP or a mismatched dNTP. This reveals that RT bound to a mismatched dNTP is capable of entering into a novel nonfunctional state after dNTP incorporation. In this state, the thumb subdomain experiences inhibited dynamics and the primer/template breaks contacts with the p51 subunit. The incorporation of the correct dNTP shields RT from this nonfunctional state, allowing polymerization to continue. In summary, surveying structural and dynamics changes that occur in molecular dynamics trajectories alongside X-ray crystallographic structural data provides novel insights into normal RT function.
Cor triatriatum: Preoperative diagnosisand successful surgical repair in a small infant

Two patients with cor triatriatum are described, one of whom is the youngest patient with this lesion to survive surgery.
Instrumented tensile-impact tests of bone

An instrumented pendulum-type impact tester was used to obtain tensile-impact properties for compact bone. Load-time histories throughout impact were recorded. Impact tests on 50 longitudinally oriented fresh-beef-bone samples yielded a proportional limit of 9.6±4.1 ksi (66.2±28.2 MPa), an ultimate stress of 17.6±5.3 ksi (121.3±36.5 MPa) and an energy-absorption capacity of 142±85 in. Ib/in.2 (24900±14900 J/m2). A static tensile strength of 14.7±2.8 ksi (101±19 MPa) was obtained from static testing of 24 additional specimens. The tensile-impact strength was 20 percent higher than the static strength. Statistically significant correlations between elastic properties, impact strength and impact energy were found. Bone microstructure and fracture-surface topography were also examined.
Evidence for distinct attentional bottlenecks in attention switching and attentional blink tasks.

E. Weichselgartner and G. A. Sperling (1987), using rapid serial visual presentation (RSVP), estimated that attention could be moved to a new spatial location within 300-400 ms. H. J. Muller and P. M. Rabbit (1989) used a spatial cuing task and found a similar time course for voluntarily redeploying attention. A separate phenomenon known as the attentional blink (AB) also follows a similar time course, yet occurs when participants attend to a single spatial location. The present study found that attention can be shifted more quickly than previously estimated and that part of the deficit observed during searches of spatially distinct RSVP streams is due to an AB. The results support some early and late selection accounts for the temporal dynamics of visual attention and suggest different bottlenecks during visual selection. The implications for visual search and visual processing are discussed.
Atom Transfer Radical Polymerization of N,N-Dimethylacrylamide

The polymerization of N,N-dimethylacrylamide (DMA) under atom transfer radical polymerization (ATRP) conditions was studied. The ligand, solvent (water, n-butanol, and toluene), initiator, and Cu halide were varied. High monomer conversions were obtained using the Me4Cyclam ligand. Polymerizations in water that were initiated at room temperature were complete within minutes. However, none of the experimental conditions produced a controlled polymerization. This conclusion is based on broad molecular weight distributions, poor agreement between theoretical and experimental Mn, incremental monomer addition experiments, and end group analysis. We believe that the Cu salts complex to the amide group of the chain ends and stabilize the radical. This stabilization retards the deactivation step in ATRP and produces an unacceptably high concentration of radicals which leads to spontaneous termination reactions. In addition, we have indirect evidence for a cyclization reaction involving nucleophilic Br displacemen...
ATF6α Optimizes Long-Term Endoplasmic Reticulum Function to Protect Cells from Chronic Stress

Summary In vertebrates, three proteins—PERK, IRE1α, and ATF6α—sense protein-misfolding stress in the ER and initiate ER-to-nucleus signaling cascades to improve cellular function. The mechanism by which this unfolded protein response (UPR) protects ER function during stress is not clear. To address this issue, we have deleted Atf6 α in the mouse. ATF6α is neither essential for basal expression of ER protein chaperones nor for embryonic or postnatal development. However, ATF6α is required in both cells and tissues to optimize protein folding, secretion, and degradation during ER stress and thus to facilitate recovery from acute stress and tolerance to chronic stress. Challenge of Atf6 α null animals in vivo compromises organ function and survival despite functional overlap between UPR sensors. These results suggest that the vertebrate ATF6α pathway evolved to maintain ER function when cells are challenged with chronic stress and provide a rationale for the overlap among the three UPR pathways.
Rho is Required for the Initiation of Calcium Signaling and Phagocytosis by Fcγ Receptors in Macrophages

Phagocytosis of bacteria by macrophages and neutrophils is an essential component of host defense against infection. The mechanism whereby the interaction of opsonized particles with Fcγ receptors triggers the engulfment of opsonized particles remains incompletely understood, although activation of tyrosine kinases has been recognized as an early step. Recent studies in other systems have demonstrated that tyrosine kinases can in turn signal the activation of small GTPases of the ras superfamily. We therefore investigated the possible role of Rho in Fc receptor–mediated phagocytosis. To this end we microinjected J774 macrophages with C3 exotoxin from Clostridium botulinum , which ADP-ribosylates and inactivates Rho. C3 exotoxin induced the retraction of filopodia, the disappearance of focal complexes, and a global decrease in the F-actin content of J774 cells. In addition, these cells exhibited increased spreading and the formation of vacuolar structures. Importantly, inactivation of Rho resulted in the complete abrogation of phagocytosis. Inhibition of Fcγ receptor–mediated phagocytosis by C3 exotoxin was confirmed in COS cells, which become phagocytic upon transfection of the FcγRIIA receptor. Rho was found to be essential for the accumulation of phosphotyrosine and of F-actin around phagocytic cups and for Fcγ receptor–mediated Ca 2+ signaling. The clustering of receptors in response to opsonin, an essential step in Fcγ-induced signaling, was the earliest event shown to be inhibited by C3 exotoxin. The effect of the toxin was specific, since clustering and internalization of transferrin receptors were unaffected by microinjection of C3. These data identify a role for small GTPases in Fcγ receptor–mediated phagocytosis by leukocytes.
Symmetry of NHN hydrogen bonds in solution

Abstract A classic question regarding hydrogen bonds concerns symmetry. Is the hydrogen centered between the two donors or is it closer to one and jumping between them? These possibilities correspond to single- and double-well potentials, respectively. Isotopic perturbation of equilibrium can answer this question. This method is illustrated with 3-hydroxy-2-phenylpropenal. It is then applied to the intramolecular NHN hydrogen bonds in monoprotonated 1,8-bis(dimethylamino)naphthalenes and in N , N ′-diaryl-6-aminofulvene-2-aldimines, and the OHO in 6-hydroxy-2-formylfulvene. Mixtures of d 0,3,6,9,12 isotopologs of 1,8-bis(dimethylamino)naphthalene and its 2,7-dimethoxy derivative were synthesized, as well as the pure α- d 1 isotopologs of 6-hydroxy-2-formylfulvene and two N , N ′-diaryl-6-aminofulvene-2-aldimines. Deuterium-induced 13 C isotope shifts were measured. The splittings and intensities are consistent with perturbation isotope shifts, intrinsic shifts, or a combination of both. The most dramatic are perturbation shifts of +376 and +223 ppb in 6-hydroxy-2-formylfulvene and N , N ′-diphenyl-6-aminofulvene-2-aldimine. Perturbation shifts mean that all these hydrogen bonds are asymmetric and that each species is a pair of rapidly interconverting tautomers. This does not require a double-well potential, since solvation of one end of a single-well hydrogen bond could instantaneously stabilize one tautomer. Implications for the role of low-barrier hydrogen bonds in enzyme-catalyzed reactions are discussed. Moreover, an unusual stereochemical effect transmitted across the hydrogen bond is seen in 2,7-dimethoxy-1,8-bis(dimethylamino)naphthalene·H + , where the N -methyls show intrinsic isotope shifts both from the geminal CD 3 and from only one distant CD 3 .
A dynamic majority determination algorithm for reconfiguration of network partitions

Abstract We present a conservative consistency and recovery control algorithm for replicated files in the presence of network partitioning due to communication link failures. This algorithm supports partial replication, provides nonblocking operations by allowing update access to a file in that file's majority partition, and brings all copies up to date on all sites whenever the communication links among them are repaired. This algorithm belongs to the class of dynamic voting algorithms proposed in the recent literature. When the communication link among some partitions is reestablished, the algorithms proposed so far do not always allow the merge (reconciliation) of these partitions to form a single partition. A merge condition has to be satisfied to avoid possible inconsistencies. This is undesirable because in a system with more than one replicated file, two or more partitions cannot be integrated to form a single partition if any one of the replicated fields in these partitions does not satisfy the merge condition. This restriction might cause the system to remain partitioned for a long time even if communication links are repaired. (In the previous papers, such a problem is not addressed, since a system with only one replicated file is assumed.) The algorithm proposed in this paper avoids any such merge condition and integrates the partitions whenever a communication link failure is repaired, thus providing a higher degree of availability. This work formalizes the presentation of algorithms and data structures for implementation.
Response to chronic insulin administration: effect of area postrema ablation.

Abstract The effects of daily administration of protamine zinc insulin (PZI) on plasma insulin and glucose levels and on food intake and body weight of rats with lesions of the area postrema and adjacent caudal-medial portions of the nucleus of the solitary tract (APX rats) were examined. Prior to insulin treatment, APX rats weighed less and had lower plasma immunoreactive insulin (IRI) levels than nonlesioned controls but did not differ from controls in plasma glucose levels. Five daily injections of 5 U/kg PZI raised plasma IRI and lowered plasma glucose levels similarly for both lesioned and nonlesioned rats. When injected with increasing doses of PZI over a 30-day period, both lesioned and nonlesioned rats showed increases of food intake and rate of weight gain in response to 8 U/kg PZI. These data indicate that APX does not affect either physiological or behavioral responses to chronic peripheral insulin administration.
Deafferentation-induced changes in protein kinase C expression in the rat cochlear nucleus

Isoforms of the signal transducing molecule, protein kinase C (PKC), may play a role in neural plasticity following sensory deafferentation. To explore the role of PKC in central auditory plasticity, we studied the effect of auditory deafferentation on the expression of PKC βI, βII, γ, and δ in the rat dorsal (DCN) and ventral cochlear nucleus (VCN), using immunocytochemistry. Male rats were treated with kanamycin and furosemide to induce hair cell loss. At various intervals post-treatment, brains were perfusion-fixed and processed for immunocytochemistry. Following deafferentation, we observed a gradual increase in PKC βI immunoreactivity (ir) in the deepest layers of the DCN, possibly representing synapses of primary afferents or parallel fibers on unlabeled neurons. Correlated with this, we observed an increase in the number of neurons in the deep DCN that showed PKC δ ir. In controls, we observed PKC γ ir in small ovoid cells concentrated in the middle layer of the DCN. From days 4 through 14 after deafferentation, we found an increase in the intensity of staining of these cells, with a return toward control levels by day 28. Finally, Purkinje-like cells (PLC) in the VCN, which express only PKC δ in control rats, began to express PKC γ after deafferentation, correlated with increased expression of calbindin D28k in PLC. Thus PKC isoforms are differentially regulated in the CN following deafferentation, supporting a role for PKC in auditory plasticity.
A Comparison of Potassium Imbalance and Antihypertensive Drug use in Black and White Elders

Abstract Pharmacological treatment for hypertension can result in potassium (K + ) imbalance. The goal of this study was to compare the prevalence of hospitalization with a diagnosis of hyper- and hypokalemia (hyperK and hypoK) in black and white elders, and to examine whether this difference is related to their antihypertensive (antiHTN) medication use. Subjects included all participants in the Pharmaceutical Assistance Contract for the Elderly (PACE), who were hospitalized during the 1 st quarter of 1996 (N=28,787). PACE is a program for PA residents aged 65+ yrs who meet certain income requirements. The sample was 80% female, 93% white and 6.2% black, and the mean age was 79yrs. Blacks had a higher rate of hospitalization with hyperK than did whites (.13% vs. 0.05%, p=.001). There was no difference in the rate of hypoK between groups. After controlling for sex and age, blacks were at greater risk for hyperK than whites (OR=1.95). There was no significant difference in risk for hypoK. Of the antiHTN medications that might affect K + balance, blacks had a higher risk of hyperK when taking K + -sparing diuretics and ACE inhibitors compared to whites (OR=2.94 and 1.80). The results suggest that blacks are at an increased risk for hyperK when taking certain medications, and thus may benefit from counseling on decreasing potassium intake. Funded in part by SmithKline Beecham and an NIA predoctoral fellowship
Vasodilatory and toxic effects of spin traps on aerobic cardiac function

Abstract The objective of this study was to compare the effect of several structurally related nitrone and nitroso spin traps on the function of the isolated bicarbonate-buffer perfused rat heart model. Spin traps were α-phenyl- tert -buthyl N -nitrone (PBN), α -(4-pyridyl-1-oxide)- N - tert -butyl nitrone (POBN), 2-methyl-2-nitroso prapane (MNP), 2-hydroxymethyl-2- nitroso propane (MNP/OH), nitrosobenzene (NB), dibromonitrosobenzene-sulfonic acid (DBNBS), and 5, t ′-dimethyl-1-pyrroline- N -oxide (DMPO). During perfusion of hearts with increasing concentrations of spin traps, ventricular pressure, coronary flow rate, and heart rate were continuously recorded. The extent of contractile recovery was subsequently measured upon return to spin-trap free perfusion. The percentage of maximum increase in coronary flow with PBN, POBN, MNP, MNP-OH, NB, DBNBS, and DMPO were 11, 40, 45, 66, 28, 28, and 29%, respectively. Thus, all nitroso and nitrone spin traps studied acted as vasodilators. Over the dose range studied, POBN, MNP, MNP/OH, and DMPO did not exert any chronotropic effect. PBN, NB, and DBNBS exerted a negative chronotropic effect at higher concentrations. All spin traps studied, with the exception of DMPO, exerted a negative inotropic effect at the higher concentrations studied. We conclude that all spin traps examined acted as coronary vasodilators. Their negative chronotropic and inotropic effects were minimal in comparison and only manifest at the higher concentrations studied.
Should DPD analysis be required prior to prescribing fluoropyrimidines

Dihydropyrimidine dehydrogenase (DPD) is a key enzyme in the metabolic catabolism of chemotherapeutic agent 5-fluorouracil (5FU) and its derivatives, including capecitabine. Numerous genetic mutations have been identified in the DPD gene locus (DPYD), with a few key variants having functional consequences on enzymatic activity. Deficiencies in DPD activity have been shown to cause 5FU-treated cancer patients to experience severe drug-related toxicities, often requiring extensive medical intervention. We review the performance of assays that assess DPD and DPYD status, with an emphasis on the robustness for routine clinical applications. None of the current strategies are adequate to mandate routine DPD testing prior to starting a fluoropyrimidine-based therapy. However, further research and technological improvements will hopefully allow prospective identification of potentially toxic patients, in order to reduce the number of patients with severe, life-threatening side effects to 5FU treatment.
A note on the exponential kernel approximation

Abstract Integral equations, which appear in the study of radiative transfer through a semi- infinite, emitting-absorbing, and isotropically scattering medium, are investigated. Closed form, approximate solutions, which were obtained by using an exponential kernel approximation, are presented and compared with exact solutions.
Single-Molecule-Sensitive FRET in Freely-Diffusing Attoliter Droplets

Fluorescence resonance energy transfer (FRET) from RNA confined in freely-diffusing attoliter aqueous droplets shows dramatic differences from that of RNA in solution. First, the use of droplet confinement is shown to substantially increase the signal-to-noise ratio of single-molecule sensitive measurements. However, a distinct shift in FRET is also observed. These differences can be attributed to a modified pH in the confining environment, which is a result of the well-documented autolysis of water and accumulation of hydroxide ions near the water interface. This outcome has implications for the use of droplets for protein crystallization, nanoparticle synthesis, biomicrofluidics, and analytical chemistry, where careful attention to the use of appropriate buffers or surfactants to control pH in the confined phase will be required. This work was funded by NSF MCB-0920139 and NSF DBI-1152386.
Authigenic molybdenum formation in marine sediments: A link to pore water sulfide in the Santa Barbara Basin

Pore water and sediment Mo concentrations were measured in a suite of multicores collected at four sites along the northeastern flank of the Santa Barbara Basin to examine the connection between authigenic Mo formation and pore water sulfide concentration. Only at the deepest site (580 m), where pore water sulfide concentrations rise to .0.1 mM right below the sediment water interface, was there active authigenic Mo formation. At shallower sites (550, 430, and 340 m), where pore water sulfide concentrations were consistently ,0.05 mM, Mo precipitation was not occurring at the time of sampling. A sulfide concentration of ;0.1 mM appears to be a threshold for the onset of Mo-Fe-S co-precipitation. A second threshold sulfide concentration of;100 mM is required for Mo precipitation without Fe, possibly as Mo-S or as particle-bound Mo. Mass budgets for Mo were constructed by combining pore water and sediment results for Mo with analyses of sediment trap material from Santa Barbara Basin as well as sediment accumulation rates derived from 210 Pb. The calculations show that most of the authigenic Mo in the sediment at the deepest site is supplied by diffusion from overlying bottom waters. There is, however, a non-lithogenic particulate Mo associated with sinking particles that contributes #15% to the total authigenic Mo accumulation. Analysis of sediment trap samples and supernant brine solutions indicates the presence of non-lithogenic particulate Mo, a large fraction of which is easily remobilized and, perhaps, associated with Mn-oxides. Our observations show that even with the very high flux of organic carbon reaching the sediment of Santa Barbara Basin, active formation of sedimentary authigenic Mo requires a bottom water oxygen concentration below 3 mM. However, small but measurable rates of authigenic Mo accumulation were observed at sites where bottom water oxygen ranged between 5 and 23 mM, indicating that the formation of authigenic Mo occurred in the recent past, but not at the time of sampling. Copyright © 2000 Elsevier Science Ltd
Are there bound states of Higgs scalars or weak vector bosons in the 100 GeV region

Abstract It has been suggested that certain anomalous e + e − γ events observed near the mass of the Z 0 boson arise from a bound state of Higgs or weak bosons. It is shown that such a bound state does not naturally occur if the particles are bound in a potential arising from either scalar or vector exchange and if the motion is governed by a two-body generalization of the Klein-Gordon equation. Bound states in the desired energy range can occur, however, if both vector and scalar exchange are present.
Using Label-Free Screening to Investigate Stem-Cells from their Microanatomical Niche

An understanding of both embryonic organogenesis and adult tissue regeneration relies on isolating and characterizing stem cells. In general, these cells are difficult to study because they constitute minute populations in organ niches and express multiple cell-surface markers, only some of which are identified. Furthermore, their properties change quickly in vitro and possibly even during isolation procedures. We have recently developed a label-free cell-analysis platform to characterize key cell-surface markers in single, functional organ stem cells directly isolated from their micro-anatomical niche, i.e. muscle (satellite) stem cells from single myofibers. Our platform is based on measuring the transit time of single cells as they transit a microchannel functionalized with a specific antibody. Cells that express the complementary surface antigen have a longer transit time as compared to those that do not. With this method, we have discovered that individual myofibers significantly differ from each other with respect to expression of the markers Sca-1, CXCR4, β1-integrin, and M-cadherin on their associated satellite cells. Furthermore, we have found that this heterogeneity extends to other important markers such as Notch1. Our data are the first to show the phenomenon of microniche-dependent variation in adult stem cells of the same tissue, emphasizing the complexity of the muscle stem-cell population and prompting new studies aimed at understanding the purpose for such heterogeneity. Ultimately, our platform introduces a new method for stem-cell analysis, as FACS and MACS do not allow for niche-specific characterization. Microscopy, while capable of imaging stem cells in their respective niches, is neither precise nor quantitative. Overall, our method can be broadly applied to the quantitative analysis of single stem cells isolated from their microniches in other adult and developing organs, leading to new discoveries on stem-cell properties and regenerative potential.
Reversible Renal Failure in the Nephrotic Syndrome

Acute, usually reversible, renal failure has been observed in patients with normal or minimally altered glomeruli on renal biopsy. This review aims to examine the clinical features of acute renal failure in these patients and to evaluate factors that may contribute to the reduction in glomerular filtration rate (GFR). In an analysis of 79 cases affecting 75 patients reported in the English literature since 1966, with acute renal failure associated with minimal change disease or mild histopathological changes in glomeruli, the average age was 58 +/- 2 years (mean +/- 5 SEM), urine protein excretion 11.6 +/- 0.6 g/d, and serum albumin level 19 +/- 1 g/L (1.9 +/- 0.1 g/dL). Acute renal failure was documented an average of 29 +/- 5 days after onset of nephrotic syndrome, and persisted for 7 weeks in 62 episodes in the 58 patients in whom recovery of renal function occurred. Fourteen patients died of uremia or required chronic dialysis, and 3 were lost to follow-up. Although plasma volume depletion was sometimes cited as the cause of renal failure, objective signs of hypovolemia were not documented and most patients did not improve after treatment designed to correct volume deficits. In contrast, histopathological changes consistent with acute tubular necrosis (ATN) were observed in at least 60% of cases. Since the pathogenesis of acute renal failure in minimal change nephrotic syndrome is unknown, we evaluated hemodynamic determinants of GFR in patients with minimal change disease with normal or near-normal renal function, and in relevant animal models, to obtain insights into the effect of nephrotic syndrome on GFR. Although acute renal failure is uncommon, GFR is reduced concurrently with nephrotic syndrome in approximately 30% of children and adults. Absolute and effective blood volume and renal plasma flow are relatively well preserved. However, clinical and experimental observations suggest that the glomerular ultrafiltration coefficient may be reduced by as much as 50%. These findings, together with renal biopsy changes in cases with acute renal failure, suggest that severe reductions in GFR in some patients with minimal change nephrotic syndrome may result from an interaction between acute ischemic tissue injury and preexisting intrinsic renal abnormalities.
Connexins and Olfactory Synchronicity: Toward the Olfactory Code

A striking example of neuronal synchronization occurs in the mammalian main olfactory bulb where mitral cells that project to the same glomerular unit display highly synchronized spike activity. In this issue of Neuron, Christie et al. use mice deficient for the gap junction protein connexin36 (Cx36) to demonstrate that Cx36-mediated electrical coupling underlies such synchrony.
Type II solar radio bursts, interplanetary shocks, and energetic particle events

Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies awhich indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients.
Computer simulation models of a hooked beach shoreline configuration

ABSTRACT Computer simulation models are developed to investigate the formation of a hooked beach shoreline shape in the lee of a rocky headland. The modeling technique combines two one-dimensional cell systems aligned at right angles to each other so that beach erosion can proceed in two directions. This method is more versatile than a single one-dimensional model yet it avoids the complexity of a two-dimensional array. In the hooked portion of the beach the shape of the refracted-diffracted wave front is an arbitrary function of the offshore wave approach angle. The results indicate that the shape of the hooked beach is dependent on the direction of wave approach, and the shape of the refracted-diffracted wave front. Many of the configurations obtained can be fairly closely approximated by a ogarithmic spiral within the shadow zone.