cssi/SciSciGPT-SciSciNet huggingface dataset:
The Carbon Dioxide Hydration Activity of Carbonic Anhydrase I. STOP-FLOW KINETIC STUDIES ON THE NATIVE HUMAN ISOENZYMES B AND C

The kinetics of catalysis of CO2 hydration by human carbonic anhydrases B and C (EC 4.2.1.1) has been reinvestigated with use of an improved pH indicator stop-flow approach that was checked by studying the uncatalyzed rate of hydration. The Michaelis-Menten parameters were determined between pH 5.8 and 8.8 in noninhibitory buffers. For both isoenzymes Km was independent of pH, whereas Vmax increased with increasing pH. These results are similar to the findings of others on bovine carbonic anhydrase, but differ from the earlier report of Gibbons and Edsall (J. Biol. Chem., 239, 2539 (1964)) in the finding that Km is pH independent. Despite the differences between the low and high activity forms of carbonic anhydrase, there are close kinetic similarities between them that indicate underlying similarities in active site structure. Imidazole inhibits the B enzyme, apparently competitively, but has no effect on the C enzyme. N-Methyl substitution of imidazole abolishes its inhibitory effect. Nitrous oxide does not inhibit catalysis of CO2 hydration by either of the two human isoenzymes, or by bovine carbonic anhydrase. The infrared absorption studies of Riepe and Wang (J. Biol. Chem., 243, 2779 (1968)) had indicated that N2O and CO2 bind competitively to a site identified as the substrate-binding site. The present kinetic results are interpreted as representing a great specificity of carbonic anhydrase for the binding of its substrate CO2. It is proposed that the enzyme-catalyzed hydration of CO2 requires, not only water activation by a basic group, but also charge neutralization in the transition state by an electron acceptor function. The zinc-bound water in carbonic anhydrase could be involved in both donor and acceptor roles.
Rules of evidence for cancer molecular-marker discovery and validation

According to some claims, molecular markers are set to revolutionize the process of evaluating prognosis and diagnosis for cancer. Research about cancer markers has, however, been characterized by inflated expectations, followed by disappointment when original results can not be reproduced. Even now, disappointment might be expected, in part because rules of evidence to assess the validity of studies about diagnosis and prognosis are both underdeveloped and not routinely applied. What challenges are involved in assessing studies and how might problems be avoided so as to realize the full potential of this emerging technology?
Microgrid automation assisted by synchrophasors

This paper presents synchrophasor deployment for microgrid automation applications. A microgrid, which is the main component of future smart grids, requires sophisticated measurement and control capabilities. Conventional RTU based automation approaches suffer from slow measurement update and lack of time-stamp values. In this study, a time-synchronized control approach is proposed for a deployable hardware-based microgrid involving a synchronous generator and an inverter based DER. Protection event analysis, islanding detection, re-synchronization, and online remote generation unit dispatch studies are realistically demonstrated in hardware in a laboratory based test-bed.
Elevation of cyclic guanosine 3',5'-monophosphate levels in dog thyroid slices caused by acetylcholine and sodium fluoride.

Abstract Cyclic guanosine 3',5'-monophosphate (cyclic GMP) levels were determined in dog thyroid slices using the protein-binding method. [3H]Guanine incorporation into cyclic GMP was also determined by thin layer chromatography. Basal levels of cyclic GMP in dog thyroid slices were usually 10 to 30 pmoles per g wet tissue. These values were at least 10-fold lower than the cyclic adenosine 3',5'-monophosphate (cyclic AMP) levels. Cyclic GMP levels were significantly increased by acetylcholine (5.5 x 10-7 m to 5.5 x 10-5 m) and NaF (10-2 m) after a 1-min incubation. Increases (5 to 10-fold) were observed after 5- and 20-min incubations with acetylcholine (5.5 x 10-5 m) and after a 20-min incubation with NaF (10-2 m). Neither thyroid-stimulating hormone (100 milliunits per ml) nor prostaglandin E1 (2.8 x 10-5 m) increased cyclic GMP levels during 1-,5-, and 20-min incubations. Acetylcholine and NaF also increased [3H]guanine incorporation into cyclic GMP. The effect of acetylcholine was inhibited by atropine (1.6 x 10-4 m). Acetylcholine and NaF had little or no effect on cyclic AMP levels, while thyroid-stimulating hormone and prostaglandin E1 markedly increased cyclic AMP concentrations. In liver slices of the rat, acetylcholine increased cyclic GMP levels 2-fold, but NaF had no effect. These results indicate that the levels of cyclic GMP and cyclic AMP in dog thyroid slices are regulated by separate hormonal and metabolic mechanisms.
Lessons from the study of scholarly communication for the new information era

The rich body of literature examining communications flow in the research context, an area where Professor Belver Griffith made major contributions, has very direct relevance to the relatively newly emerging recognition in the business community of the importance of knowledge creation and deployment to the competitive performance of an organization. This essay examines and delineates some of those lessons, specifically the tension between open and rich communications versus the need to protect intellectual property; the importance of environmental awareness and serendipity, and achieving the correct balance with efficient use of information searching time; the importance of end-user training; and crafting the balance in knowledge management between codifications and personalization.
Surface stabilization of organics on hematite by conversion from terminal to bridging adsorption structures

Insight into the complexation of organic molecules on hematite surfaces was obtained from molecular-level studies of a simple probe molecule (methanol) with the R-cut surface of hematite. The R-cut crystal orientation of hematite, designated in this paper as -Fe2O3(012), has two stable surface structures under ultrahigh vacuum (UHV) conditions based on low-energy electron diffraction (LEED) measurements. These are a (11) structure consisting of a bulk terminated arrangement of undercoordinated Fe 3 and O 2 surface sites and a (21) reconstructed structure with unknown atomic structure. Whereas the (11) surface is essentially free of Fe 2 , the (21) surface possesses a high surface concentration of Fe 2 sites based on electronic structure measurements using electron energy loss spectroscopy (EELS). Methanol adsorbs disso- ciatively on the (11) surface by coordination of the molecule's oxygen atom at a Fe 3 site followed by transfer of the alcohol proton to a bridging O 2 surface site, resulting in terminal OCH3 and bridging OH groups. Most of the dissociated methanol molecules recombine during heating and desorb in vacuum as methanol at 365 and 415 K for the (11) and (21) surfaces, respectively. However, a significant amount of the terminal OCH3 and bridging OH groups interchange as the surface is heated above room temperature (RT), resulting in bridging OCH3 and terminal OH groups. The bridging OCH3 groups are retained on the surface to higher temperature than the terminal OCH3 groups, but eventually decompose at about 550 K via a disproportionation reaction that forms gaseous CH3OH and H2CO. As a result of the disproportionation reaction, some surface Fe 3 sites are reduced to Fe 2 sites. The exchange process competes more successfully with recombinative desorption of methanol (from reaction of terminal OCH3 and bridging OH groups) on the (21) surface, despite the fact that this surface is already partially reduced, because terminal OCH 3 groups are more stable on this surface than on the (11) surface. Based on these molecular-level findings, extensive exchange terminal organic ligands and bridging OH groups may play a significant role in stabilizing organics on hematite mineral surfaces. Such exchange processes may also play a role in destabilizing hematite surfaces toward reductive dissolution. Copyright © 2003 Elsevier Science Ltd
The effect of transverse dispersion on solute transport in soils

Abstract Most theoretical and experimental investigations of solute transport involve one-dimensional problems (i.e. soil column studies), whereas in reality many soil pollution problems concern transport and flow in more than one dimension. This study investigates two-dimensional transport, with emphasis on the contribution of transverse dispersion to solute transport. Three problems were studied with a finite element code. The first problem involved one-dimensional flow parallel to the interface of two layers with differing pore-water velocity. The early arrival of the solute at the end of the low-permeability layer and the increase in solute spreading for both layers, as a result of transverse dispersion, were demonstrated. The two other problems concerned transport of a pollutant from a point source and a diffuse source, respectively, located at the soil surface. The magnitude of the transverse dispersion coefficient influenced the region to which the pollution extended as well as the intensity of the pollution.
Incidental brain lesions in children: to treat or not to treat?

Central nervous system (CNS) lesions that are discovered incidentally when imaging children for problems that were unrelated to the detected lesion pose a dilemma to physicians. Because there are few data on the outcome of such cases, we retrospectively reviewed the clinical course of a group of children followed at our institution with brain lesions found incidentally on neuro-imaging. A database of all children with brain lesions followed at the University of Rochester medical center from 2000 to 2010 was reviewed. Data were obtained regarding presentation, magnetic resonance imaging (MRI) features, treatment, progression-free survival, and overall survival of children with brain lesions found incidentally. Of the 244 children with brain lesions seen over this time period, 21 (8.6%) were found to have incidentally discovered brain lesions. Of these 21 children, 12 (57%) underwent surgical resection of their brain lesions. Ten patients (48%) had symptoms considered to be unassociated with the detected lesion. Lesions were found in the cerebellum (n = 7, 33%), midline (n = 5, 24%), and cerebrum (n = 9, 43%). All lesions were ≤5 cm in diameter. Eight patients (38%) had surgery at presentation, one because of imaging features suspicious for a posterior fossae ependymoma, and the seven others because of location in the posterior fossae or brain stem. Of the remaining 13 patients, five had progression of disease on serial MRI scans: four underwent surgery and the fifth was monitored and remained stable after the initial progression stabilized. Nine of the ten patients (90%) with posterior fossae lesions underwent surgery, while only three of 11 with supratentorial lesions underwent surgery (27%) (P = 0.006). The progression free survival was 94% at 12 months (95% CI 65–99%) and 71% at 24 months (95% CI 39–88%). At a median follow-up of 32 months, the overall survival was 100%. Incidentally detected CNS lesions are usually small. The outcome for children with such lesions is excellent. Close monitoring of these patients with serial MRIs may be a safe alternative to immediate biopsy and/or resection for select patients.
Molecular Deficiency of Glucose-6-Phosphate Dehydrogenase in Primaquine Sensitivity

GENETICALLY determined deficiencies in activity of human glucose-6-phosphate dehydrogenase (G–6–PD) occur among various ethnic groups. The deficiency affecting 8–12 per cent of American Negro males is known as primaquine sensitivity and is incompletely expressed: affected persons have 7–15 per cent of the normal activity of erythrocytic G–6–PD and an even higher proportion of activity of this enzyme in some other tissues1,2. In view of similarities in qualitative characteristics between the partially purified G–6–PD of affected Negroes and that of normal persons, one of us has questioned the possibility that sensitive Negroes have a G–6–PD that is impaired in its catalytic efficiency (turnover number)3. A comparative examination of more extensively purified G–6–PD's seems to offer new evidence on this subject.
Severe Systemic Inflammatory Response Syndrome With Shock and ARDS Resulting From Still's Disease: Clinical Response With High-Dose Pulse Methylprednisolone Therapy

Adult-onset Still's disease, the adult variant of the systemic form of juvenile arthritis, is an uncommon systemic inflammatory disorder of unknown etiology characterized by high spiking fevers, neutrophilic leukocytosis, arthritis, and an evanescent rash. There is often a delay in reaching a firm diagnosis. Differential diagnoses include infection, malignancy, and various immunologic disorders. Increased ferritin levels are of particular value in establishing the diagnosis. Clinical response to high-dose corticosteroids may be dramatic. We report a case of a 29-year-old woman who had recently been investigated for fever of unknown origin, and who presented to our hospital with high fever and hypotension. Her condition rapidly deteriorated with the development of ARDS, disseminated intravascular coagulation, and shock. The patient had a markedly elevated serum ferritin concentration of 26,000 ng/mL. High-dose pulse methylprednisolone therapy resulted in a remarkable clinical improvement. Such a severe case of systemic inflammatory response syndrome, masquerading as septic shock, has not been reported previously.
Categorical algebra for continuum micro physics

Using the setting of a topos equipped with a specified infinitesimal time-interval, we try in part I to clarify the idea of lawful motions as morphisms in a category whose objects are laws of motion on state spaces, and in part II to develop specific relations between states, bodies and particles. A very general scheme to make mass distributions yield notions of inertia and hence of force is discussed. Part III concerns a special notion of a body having just one point, yet containing rich microstructure; such a body is placed in space and, in general, treated like any other body. In part IV some detailed homogeneous and quadratic examples are defined.
Introns in histone genes alter the distribution of 3′ ends

Chimeric genes were constructed which contained either a histone or globin promoter, a human alpha-globin coding region as a cDNA or containing one or both intervening sequences, and the 3' end of a mouse histone H2a gene. The genes were introduced into mouse L cells or Chinese Hamster Ovary cells. The genes containing at least one intervening sequence produced two mRNAs in about equal amounts, one which ended at a cryptic polyadenylation site 33 nucleotides 3' to the normal histone mRNA 3' end and one which ended at the normal histone 3' end. In contrast, the same construct containing a globin cDNA yielded mRNA ending only at the correct histone 3' end. Similar proportions of polyadenylated and non-polyadenylated mRNA were obtained when the cryptic polyadenylation signal was replaced with the globin polyadenylation signal. More than 90% of the transcripts were accurately spliced. All of the unspliced transcripts had histone 3' ends.
Preservers for norms of Lie product

Let ‖ · ‖ be a unitary similarity invariant norm on the set Mn of n × n complex matrices. A description is obtained for surjective maps φ on Mn satisfying ‖AB−BA‖ = ‖φ(A)φ(B)−φ(B)φ(A)‖ for all A,B ∈Mn. The general theorem covers the special cases when the norm is one of the Schatten p-norms, the Ky-Fan k-norms, or the k-numerical radii.
Interaction of pancake vortices with c-axis plasmon in Josephson-coupled layered superconductors

The power-law dependence of plasma resonance frequency on magnetic field applied along the c-axis is explained in the model of strong disorder in pancake positions along the c-axis. The line width of plasma resonance is explained by inhomogeneous broadening caused by random positions of pancake vortices in the vortex glass phase. This leads to a nearly temperature independent line width which is inversely proportional to magnetic field. The dynamic interaction of vortices with plasmon is calculated. It is ineffective in fields studied but may become stronger in crystals with weaker pinning or in higher magnetic fields.
950 ALTERNATIVE PATHWAY (AP) OPSONIC ACTIVITY OF NEWBORN (NB) SERA AS MEASURED BY CHEMILUMINESCENCE (CL)

Defects in the AP of complement are thought to play a role in the susceptibility of newborns (NB) to infection. The CL assay was used to measure the ability of varying quantities of 20 cord sera to opsonize zymosan (Z). Concentrations of AP components were correlated with CL and outcome. Luminol enhanced CL was performed using adult polymorphonuclear leukocytes to react with the opsonized Z. The cord sera was found to contain 30-70% of normal concentrations of C3, factor B, properdin, B1H, and C3bINA. Mean opsonization as measured by CI. was decreased for cord sera when compared to controls; however, some NB sera demonstrated normal ability to opsonize Z. Opsonic activity varied significantly only with the βlH concentration of the serum. β1H, along with C3bINA, is known to regulate the activity of C3 and factor B in the AP so that the ratio of C3+factor B/βlH+C3bINA in non-NB's is approximately 1.0. In the cord sera of 200 uninfected NB's, however, this ratio was 1.3 (p < 0.001) suggesting an altered regulatory mechanism for the normal NB. Eight of 9 NB's who experienced systemic infection in the first few days of life had a ratio of AP components equivalent to the non-NB's. These data demonstrate that failure to develop a typical neonatal regulatory pattern may play a role in defective opsonic activity and that CL may be used to study this activity in NB sera. The ability of NB sera to opsonize Z, however, does not predict susceptibility to infection.
A quasi-power-gated low-leakage stable SRAM cell

Leakage power dissipation and stability continues to be a major concern in deep-submicron SRAM cell design. In this paper, a quasi-power-gating approach that reduces the leakage power dissipation in an SRAM cell while maintaining stability is proposed. As compared to a standard 6-transistor SRAM, it consists of four additional NMOS transistors. In the active mode, the cell is activated by enabling two NMOS transistors in the pull-down path of the inverter. In the idle mode, a quasi-power-gating scheme is employed to reduce leakage by utilizing stack effect. It was found that this cell resulted in about 39.54 percent and 30.5 percent leakage power savings at a supply voltage value of 1V and 300mV respectively. A stability increase was also observed when compared to the standard non-power-gated 6-transistor SRAM cell.
Autobiography, Reputation, and the Self: On the Role of Evaluative Valence and Self-Consistency of the Self-Relevant Information

The effects of retrieving self-consistent or inconsistent behavioral and social reputation information on the speed of subsequent trait self-descriptiveness judgments was examined in three experiments. Across the three investigations, priming self-descriptiveness judgments with judgment consistent behavioral or social reputation information facilitated self-judgments compared to appropriate control self-judgments. In contrast, priming with inconsistent behavioral or reputational information did not facilitate self-descriptiveness judgments relative to controls. Experiment three also demonstrated that priming self-descriptiveness judgments on traits about which one was certain with behavioral or social reputation information facilitated such judgments. Priming traits about which one was uncertain with behavioral or reputational information did not result in faster self-descriptiveness judgments. Results are discussed with respect to the processes involved in making self-descriptiveness judgments.
Extracellular cysteine/cystine redox regulates the p44/p42 MAPK pathway by metalloproteinase-dependent epidermal growth factor receptor signaling

Previous research shows that stimulation of proliferation of colon carcinoma (Caco-2) cells by a more reduced extracellular cysteine/cystine (Cys/CySS) redox state occurs with no apparent effect on...
Conflict resolution for readers and writers

For those of us who have been teaching Operating Systems for years, you may remember with nostalgia the days when Operating Systems texts [ex: Deitel 1984] included Ada code to illustrate solutions for concurrency problems. I find concurrency the most difficult topic to teach in Operating Systems, and expressing solutions in Ada is a strong teaching aid. Ada's tasking construct is powerful and readable. In addition, an Ada Programming Support Environment enables hands-on experimentation.The Readers/Writers problem, a classic mutual exclusion synchronization problem, puzzled computer science professionals for years. Explaining these solutions, as presented in current Operating Systems texts, is daunting.We contrast code expressed in C to that proposed by Burns [Burns1985] and Barnes [Barnes1995] for readability. We then suggest a slight modification to obtain what we consider to be a preferred solution, one that illuminates concurrency issues in general.
Generalization of L 1 adaptive control architecture for switching estimation laws

This paper presents a modification of the estimation laws in a typical L 1 adaptive controller, by replacing the projection-based integrator in the estimation loop by a switching law with a dead-zone. We consider a class of linear systems with parametric uncertainty and input disturbance. Similar to prior solutions in L 1 adaptive control theory, the feedback structure is comprised of the three main elements, involving the state predictor, the adaptation laws and the lowpass filter. We derive the performance bounds for both the system output and the control signal and show that these can be adjusted by a suitable choice of a dead-zone interval.
High-Performance Incremental Scheduling on Massively Parallel Computers &#8212; A Global Approach

Runtime incremental parallel scheduling (RIPS) is a new approach for load balancing. In parallel scheduling, all processors cooperate together to balance the workload. Parallel scheduling accurately balances the load by using global load information. In incremental scheduling, the system scheduling activity alternates with the underlying computation work. RIPS produces high-quality load balancing and adapts to applications of nonuniform structures. This paper presents methods for scheduling a single job on a dedicated parallel machine.
On Multi-Hop Spread Spectrum Network Modeling

This paper is concerned with the graphical modeling of multi-hop spread spectrum packet radio networks. We show various network graphs, obtained using a graphics program, that illustrate typical connectivities that may be achieved for nominal values of the processing gain. The effects of the propagation power loss function and terminal transmission probability are also displayed. We introduce the notion of a soft link where the number of links included in the network depends on a link quality parameter.
Second-harmonic generation in reflection from a metallic grating

We present a nonperturbative theory of second-harmonic generation in reflection from a metallic grating. $p$-polarized light of frequency $\ensuremath{\omega}$ is assumed to be incident on the grating surface from the vacuum side, with the plane of incidence perpendicular to the grooves of the grating. We employ the method of reduced Rayleigh equations to solve Maxwell's equations in the presence of a nonlinear polarization and calculate the diffracted field at the frequency $2\ensuremath{\omega}$. In the vicinity of the frequency where the incident photon couples to surface polaritons on the grating we obtain an enhancement of the second-harmonic intensity by a factor of ~${10}^{4}$ over its value for a flat surface. The effect of the surface current density in the nonlinear polarization on the enhancement is analyzed. Numerical results are presented for a grating of silver.
Superinfection exclusion by Citrus tristeza virus does not correlate with the production of viral small RNAs

Superinfection exclusion (SIE), a phenomenon in which a preexisting viral infection prevents a secondary infection with the same or closely related virus, has been described for different viruses, including important pathogens of humans, animals, and plants. Several mechanisms acting at various stages of the viral life cycle have been proposed to explain SIE. Most cases of SIE in plant virus systems were attributed to induction of RNA silencing, a host defense mechanism that is mediated by small RNAs. Here we show that SIE by Citrus tristeza virus (CTV) does not correlate with the production of viral small interfering RNAs (siRNAs). CTV variants, which differed in the SIE ability, had similar siRNAs profiles. Along with our previous observations that the exclusion phenomenon requires a specific viral protein, p33, the new data suggest that SIE by CTV is highly complex and appears to use different mechanisms than those proposed for other viruses.
In AF or VTE, warfarin dosing by genotype improved time in therapeutic range but not clinical outcomes

Source Citation Pirmohamed M, Burnside G, Eriksson N, et al; EU-PACT Group. A randomized trial of genotype-guided dosing of warfarin. N Engl J Med. 2013;369:2294-303. 24251363
Expression of Fos immunoreactivity in rat brain during dehydration: effect of duration and timing of water deprivation.

Water deprivation induces expression of the immediate early gene c-fos in specific brain regions, most likely as a result of the activation of cells that are responsive to changes in osmolality and/or blood volume. We hypothesized that the magnitude of c-fos expression would be a function of both the duration of water deprivation and the time of day at which the deprivation started. This study was designed to examine the pattern of Fos-like immunoreactivity (FLI) following water deprivation in rats under normal light/dark conditions (nLD) and reverse light/dark conditions (rLD). Rats were deprived of water but not food either for 0, 5, 16, 24 or 48 h. As expected, hematocrit ratio (HCT), osmolality (OSM), plasma renin activity (PRA) and weight loss increased as a function of duration of water deprivation. In non-deprived rats (0 h), very little FLI was observed in most brain regions. The number of cells showing FLI increased with duration of water deprivation in the supraoptic nucleus (SON), paraventricular nucleus (PVN), organum vasculosum laminae terminalis (OVLT), median preoptic nucleus (MnPO) and subfornical organ (SFO) in both nLD and rLD conditions. However, the pattern of FLI differed between nLD and rLD conditions. Compared to corresponding nLD groups after 5 or 24-h water deprivation, rLD groups had significantly more FLI in SON and PVN, and higher PRA and HCT. Also, weight loss and FLI in the MnPO were greater after 5 h, and FLI in the SFO was greater after 24 h under rLD compared to nLD conditions. Our findings indicate that the magnitude of c-fos expression, and change in weight and plasma parameters were a function of both the duration of water deprivation and the time of day at which the deprivation started. This may result from ingestion of food early in the deprivation periods during the rLD tests, thus producing greater change in osmolality and blood volume.
Spatial and Temporal Variation of Enterobacter Genotypes in Sediments and the Underlying Hyporheic Zone of an Agricultural Stream

Population studies of enteric bacteria in an agriculturally impacted stream (Ledbetter Creek, Murray, Kentucky, USA) were conducted over a period of 2 years. Total number of bacteria, cultivated heterotrophic aerobic bacteria, and enteric bacteria showed significant differences between winter and summer. The cultivated numbers of heterotrophic aerobic bacteria and enteric bacteria were significantly more abundant in summer than in winter. The abundance of enteric bacteria was 12.9% in an upwelling zone and 9.8% in a downwelling zone in summer. Most of the enteric bacterial strains isolated on MacConkey agar were assigned to Enterobacter cloacae and E. agglomerans by API 20E and an analysis of the restriction patterns produced by amplified DNA coding for 16S rRNA (ARDRA) with the enzyme Hpa II. E. cloacae and E. agglomerans genotypes isolated from three hyporheic and gravel bar depth intervals (0-10 cm, 15-25 cm, and 30-40 cm) in summer and fall showed significant spatial variation and were heterogeneously distributed along the stream. Temperature, inorganic nutrients, and occurrence of anoxic zones affected the distribution of enteric bacteria. These techniques can be used as a model to monitor shifts among different species in the stream ecosystem.
Analysis of arsenic-iron alloys

Abstract Contrary to expectation and to published recommendation it is not possible to separate Fe(III) quantitatively from As(V) on a cation-exchange resin. lon-exchange can however be utilised for the analytical separation of iron and arsenic if the iron is reducrd to Fe(II) before the mixture is passed through the cation-exchange column.
Ceramic coating for valve seats and stems by plasma chemical vapor deposition

Abstract To extend the lifetime of the valve seats and stems used in nuclear power plants, we have developed a unique ceramic coating technique using plasma chemical vapor deposition (CVD). Multilayer coatings of Al 2 O 3 /TiN/TiC, Al 2 O 3 /TiC and TiN/TiC were deposited onto Stellite and stainless steel substrates. The mechanical and physical properties of the coatings were evaluated by various methods. The coated specimens showed good wear resistance in a high-temperature water environment. Corrosion resistance was evaluated in an autoclave at a temperature of 548 K for 200 h. The coated specimens showed excellent performance in reducing the cobalt level dissolved in the testing solution. The weight loss of the multilayer-coated AISI403 specimen, as evaluated by a cavitation erosion test, was less than 1% of that of the uncoated AISI403. However, for the coated Stellite-padded AISI316L substrate, the weight loss was almost the same as that of the uncoated specimen.
Using whole-word production measures to determine the influence of phonotactic probability and neighborhood density on bilingual speech production

Numerous lexical and sublexical factors have been reported to influence speech production in monolinguals (Storkel, 2001; Vitevitch, 2002); however, whole-word production analyses have rarely been used to measure such influences. The present study investigated the effects of phonotactic probability and neighborhood density on bilingual speech production using whole-word production measures (Ingram, 2002). Five typically developing English–Spanish bilingual children were administered a picture-naming task in English and Spanish in which stimuli varied in sublexical and lexical parameters. Their English and Spanish productions were compared with those of five age-matched monolingual English- and Spanish-speaking children, respectively. No differences were found between bilinguals and monolinguals in the respective languages; however, bilinguals evidenced greater phonological complexity in Spanish than English on words with low phonotactic probability and low neighborhood density. Whole-word approximation re...
Broad Ne VIII λ774 Emission from Quasars

Ne VIII λ774 is an important tracer of the high-ionization gas in QSOs. We examine the Ne VIII emission-line properties using new Hubble Space Telescope (HST)-FOS spectra of four sources, mean spectra derived from two QSO samples in the HST archives, and new photoionization calculations. The results support our previous claim that broad Ne VIII lines are common in QSOs, with an average flux of ~42% of O VI λ1034 and velocity widths that are ~2 to 5 times larger than O VI, C IV λ1549 and other broad lines in the same spectra. The strongest and most reliably measured Ne VIII λ774 lines (in two sources) have FWHM ~14,500 km s-1. Line profile fits in these cases show that the unusually large widths might be caused by blending with emission from N IV λ765 and O IV λ789. However, standard photoionization calculations indicate that N IV, O IV, and all other lines near this wavelength should be too weak, leaving (very broad) Ne VIII as the only viable identification for the ~774 A feature. (This conclusion might be avoided if there are large radial velocity dispersions [ 1000 km s-1] in the emitting region, and the resonant absorption of continuum photons enhances the flux in weaker lines.) The calculations also indicate that the Ne VIII-emitting regions have ionization parameters in the range 5 U 30, total hydrogen column densities of 1022 NH 3 × 1023 cm-2, and an average covering factor of 30% (for solar abundances and a nominal QSO continuum shape). The Ne VIII-emitting region is therefore more extensive, more highly ionized, and has much higher velocities than the rest of the broad emission line region (BELR). This highly ionized BELR component would be a strong X-ray warm absorber if it lies along our line of sight to the X-ray continuum source.
Forecasts of seasonal streamflow in West-Central Florida using multiple climate predictors

Summary Large-scale climate can provide predictive information for streamflow forecasts in many parts of the world. However, the optimal selection of predictors can be problematic when focusing on a localized region. This work evaluated multiple gridded climate datasets in order to determine optimal predictors of seasonal streamflow in West-Central Florida. Using persistence in streamflow, existing indices of climate, and sea surface temperature (SST) expansion coefficient time-series from singular value decomposition (SVD) analysis, this work developed probability of exceedance streamflow forecasts for multiple stations, seasons, and lead-times. Forecasts were found to be generally skillful between the September–November and April–June seasons with this range narrowing as lead time increased and skill was mainly related to the impact of the El Nino-Southern Oscillation (ENSO) on the region. Using multiple indices of ENSO that were determined by correlation and composite analyses to track its evolution from the west Pacific at long lead-times to the east Pacific at short lead-times was not found to appreciably improve forecasts over using the Nino 3.4 index alone. Using SST expansion coefficient time-series from SVD analysis was found to capture the evolution of ENSO from west to east and to provide skillful forecasts of streamflow at earlier leads (up to 7 months in advance) compared to that found by pre-defined indices, indicating the importance of predictor selection in achieving optimal forecast skill.
T-cell selection in the thymus.

Differentiation of early thymocytes into mature T cells depends upon intrathymic T cell contact with major histocompatibility complex (MHC) molecules, i.e., H-2 molecules in mice. T cell recognition of H-2 molecules in the thymus has two consequences. First, some T cells undergo a process of positive selection which leads specifically-reactive immature thymocytes to survive and differentiate into mature functional T cells. Second, T cells with high affinity for H-2 molecules undergo negative selection (tolerance). We and others have argued that positive selection is controlled by thymic epithelial cells, especially cortical epithelium, whereas negative selection reflects contact with bone-marrow (BM) derived cells. This scheme appears to be an oversimplication because we have recently found evidence that a non-BM-derived component of the thymus, presumably epithelial cells, is highly tolerogenic for CD4+ cells. Whether tolerance of CD4+ cells is controlled by cortical epithelium or medullary epithelium is unclear. In this respect it is of interest that chronic injection of mice with cyclosporine A results in selective destruction of medullary epithelial cells and impaired induction of self tolerance.
Wave breaking induced surface wakes and jets observed during a bora event

[1] An observational and modeling study of a bora event that occurred during the field phase of the Mesoscale Alpine Programme is presented. Research aircraft in-situ measurements and airborne remote-sensing observations indicate the presence of strong low-level wave breaking and alternating surface wakes and jets along the Croatian coastline over the Adriatic Sea. The observed features are well captured by a high-resolution COAMPS simulation. Analysis of the observations and modeling results indicate that the long-extending wakes above the boundary layer are induced by dissipation associated with the low-level wave breaking, which locally tends to accelerate the boundary layer flow beneath the breaking. Farther downstream of the high peaks, a hydraulic jump occurs in the boundary layer, which creates surface wakes. Downstream of lower-terrain (passes), the boundary layer flow stays strong, resembling supercritical flow.
Assessment Issues with Stepfamilies.

This column presents issues that affect families undergoing separation, divorce, and remariage, including single parenting and stepfamilies. If you have specific areas or questions that you would like discussed in this column, please write to: James H. Bray, Department of Family Medicine, Baylor College of Medicine, 5510 Greenbnar, Houston TX 77005, or call (713) 798-7751.
Reconstruction of complex chest wall defects

Background Reconstruction of complex chest wall defects represents a major challenge and requires close cooperation between the cardiothoracic and reconstructive surgeon to achieve an optimal outcome and reduce the incidence of complications. The principles of chest wall reconstruction include control of infection, local wound care, wide debridement of all necrotic and devitalalized tissues, obliteration of all residual cavities and spaces with well-vascularized tissues, reestablishment, when necessary, of the continuity and skeletal stability of the chest wall, and immediate or early definitive coverage of all defects with well-vascularized tissues. Methods This paper is based on our experience with 113 patients who underwent chest wall reconstruction for a variety of defects resulting from infection, trauma, tumor extirpation, and radionecrosis. All patients were treated with a variety of muscle flaps and/or omentum which provided obliteration of dead space and coverage. Seven patients with large anterolateral defects required additional skeletal stability with synthetic patches or mesh. Results 88.6% of patients healed without significant problems. 8.8% had major complications requiring reoperation and prolonged hospitalization while 4.4% had minor complications. Conclusions: Based on long-term experience, we believe that currently the use of well-vascularized tissue is the method of choice for reconstruction of complex chest wall defects. This provides stable coverage, reduces hospital stay, and thus lowers overall care cost for these patients.
The multilevel principle applied to sorting

Sorting algorithms are developed in the setting of iterative multilevel methods. These algorithms borrow aggregation techniques from algorithms used for the numerical solution of elliptic partial differential equations which are of optimal order in running time and storage space for structured problems. A computationally inexpensive preconditioner drives random data chosen from known distributions towards a special case for which the new sorting algorithms are of optimal order.
What is IT? New Conceptualizations and Measures of Pediatric Nurses' Acceptance of Bar-Coded Medication Administration Information Technology

New healthcare technologies, such as bar-coded medication administration (BCMA), are implemented into rich, multiple-level work system, and jointly shape work processes. We provide theoretical and ...
Evolutionary patterns in the family ostreidae larviparity vs. oviparity

Abstract A comparison was made of the evolutionary patterns among larviparous and oviparous species of the family Ostreidae. The data reveal that larviparous species have experienced a wider range of environmental variables, life history traits, and levels of genetic variation than have oviparous species. Non-parametric correlation coefficients were obtained among fifteen variables (i.e., two genetic, four environmental and nine life-history variables). Among the life-history variables, mode of larval development, fecundity, egg size, initial size of the planktonic larva and planktonic larval period were found to covary significantly with the genetic variables. In a comparison of environmental and life-history variables, the mode of larval development and habitat water depth were found to covary. The implications of these results are discussed with reference to the evolution of the family Ostreidae.
Design of a Microbreather for Two-Phase Microchannel Heat Sinks

The design of a vapor breather that uses microstructures and surface chemistry to improve two-phase microchannel heat sink performance was investigated. Test breather devices were designed, fabricated, and characterized that enabled imaging of bubble-breather interactions and understanding of geometry on breather performance. A model was subsequently developed to interpret the experimental results, which incorporates the effect of both liquid inlet flow rate and breather port vacuum level on the maximum air removal rate. This work offers insights and guidelines for the development of optimized breather structures to improve two-phase microchannel performance for thermal management applications.
Risk profiles for overweight/obesity among preschoolers

Abstract Background The epidemic of overweight/obesity among U.S. children has led to an alarming increase in health-related consequences, including early-onset diabetes and cardiovascular disease. Recent research has identified the independent contribution of several maternal and child factors to the development of childhood overweight/obesity. Few studies, however, have examined risk profiles of childhood obesity. Aim This study used classification and regression tree (CART) analysis to examine the combined effect of maternal and child factors in generating risk profiles for overweight/obesity among preschoolers. Study design Data from the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B) study were used. The sample was comprised of preschool children. CART and logistic regression models were built and compared. Results Children who were overweight/obese at two years of age had an increased risk of being overweight/obese at four years of age. Children born to overweight/obese mothers were more likely to be overweight/obese by age four, even if their BMI at two years of age was normal. Children with high birth weight (≥4000g.) were also more likely to be overweight/obese at age four years if they were born to mothers with a normal pregravid BMI, but were of a lower socioeconomic status. Among preschoolers whose mothers were black or white and who had a high pregravid BMI, breastfeeding duration and parity played an important role in determining their risk of being overweight/obese. Conclusions Classification tree analysis confirms and extends current knowledge of preschool overweight/obesity by providing preliminary risk profiles that are structured within the context of prenatal and postnatal maternal and child characteristics.
Secure and robust virtual coordinate system in wireless sensor networks

Virtual Coordinate System (VCS)-based routing provides a practical, efficient, and scalable means for point-to-point routing in wireless sensor networks. Several VCS-based routing protocols have been proposed in the last few years, all assuming that nodes behave correctly. However, many applications require deploying sensor networks in adversarial environments, making VCS-based routing protocols vulnerable to numerous attacks.In this article, we study the security of VCS-based routing protocols, with a focus on the unique component of VCS-based routing protocols, the virtual coordinate system. We first identify the security requirements of a correctly functioning VCS-based routing protocol and a set of novel attacks that can result in the violation of each of the identified requirements. The attacks target the underlying virtual coordinate system and can be mounted with low resources. However, they are epidemic in nature and are highly destructive to system performance. We then propose lightweight defense mechanisms designed specifically for resource-constrained sensor networks against each of the identified attacks. The proposed techniques require only local information on sensor nodes and take into account the unreliable nature of wireless links and network churn. Finally, we evaluate experimentally the impact of the attacks and the effectiveness of our defense mechanisms using a well-known VCS-based routing protocol, BVR. Our experiments show that the proposed techniques successfully mitigate all the identified attacks under a realistic link model and even at a high level of network churn.
Sequence alterations in the YBX2 gene are associated with male factor infertility

Objective To investigate YBX2 gene alterations in men with severe defects in spermatogenesis, including azoospermia or severe oligozoospermia, and protamine deregulation. MSY2 has been identified as a central component in the regulation of spermatogenesis in mice, but the potential role of its human orthologue, YBX2 or "Contrin," in human infertility is not known. Design A prospective cohort study. Setting University infertility clinic and associated research laboratory. Patient(s) A total of 288 men were evaluated. Diagnoses were made of complete azoospermia, severe oligozoospermia, and protamine deregulation, or men were of known paternity. Intervention(s) Deoxyribonucleic acid (from peripheral blood) and semen samples were collected and analyzed for gene mutations and semen parameters respectively. Main Outcome Measure(s) YBX2 gene alterations. Result(s) YBX2 sequence analysis revealed 15 polymorphic sites, of which seven polymorphisms were present at a statistically higher frequency in one or both of the patient populations than in controls. Of these seven, two resulted in an amino acid substitution in the highly conserved cold shock domain and one resulted in a highly significant synonymous change in exon 8 of infertile patients. The frequency of single nucleotide polymorphisms was significantly elevated in patients with infertility, particularly in men with abnormal protamine expression. Conclusion(s) These data indicate a significant association between gene alterations in the YBX2 gene and abnormal spermatogenesis in humans, including a potential role in altering protamine expression, and implicate YBX2 gene alterations as a potential cause of male factor infertility.
Orally and Nasally Induced Tolerance Studies in Ocular Inflammatory Disease: Guidance for Future Interventions

: The induction of both oral and nasal tolerance has been used in both experimental models of ocular disease and clinically. Initial work centered around the abrogation of experimental autoimmune uveitis using either one or two whole uveitogenic antigens. Other models of ocular disease have included a corneal transplant model, demonstrating that feeding splenocytes from the donor strain of rats enhanced corneal engraftment. Fragments of pertinent antigens have been shown to alter the expression of experimental uveitis and possibly human disease. A randomized, masked study in uveitis provided valuable information for future studies, demonstrating that single antigen feeding provided far better protection than the feeding of multiple antigens. This review will deal with animal and human studies in the treatment of ocular inflammatory disease with the goal of extracting from past experience how to construct a future study in humans.