cssi/SciSciGPT-SciSciNet huggingface dataset:
pH and deuterium kinetic isotope effects studies on the oxidation of choline to betaine-aldehyde catalyzed by choline oxidase.

The FAD-dependent choline oxidase catalyzes the four-electron oxidation of choline to glycine-betaine, with betaine-aldehyde as intermediate. The enzyme is capable of accepting either choline or betaine-aldehyde as a substrate, allowing the investigation of the reaction mechanism for both the conversion of choline to betaine-aldehyde and of betaine-aldehyde to glycine-betaine. In the present study, pH and deuterium kinetic isotope effects with [1,2-2H4]-choline were used to study the mechanism of oxidation of choline to betaine-aldehyde. The V/K and Vmax pH-profiles increased to limiting values with increasing pH, suggesting the presence of a catalytic base essential for catalysis at the enzyme active site. From the V/K pH-profile with [1,2-2H4]-choline, a pKa of 8.0 was determined for the catalytic base. This pKa was shifted to 7.5 in the V/K pH-profile with choline, indicating a significant commitment to catalysis with this substrate. In agreement with this conclusion, the D(V/K) values decreased from a limiting value of 12.4 below pH 6.5 to a limiting value of 4.1 above pH 9.5. The large D(V/K) values at low pH are consistent with carbon–hydrogen bond cleavage of choline being nearly irreversible and fully rate-limiting at low pH. Based on comparison of amino acid sequences and previous structural and mechanistic studies on other members of the GMC oxidoreductase superfamily, the identity of the catalytic base of choline oxidase is proposed.
Effect of maturity on carbohydrate changes in sugar snap pea pods during storage

Abstract To determine the effect of maturity at harvest on compositional changes during storage, sugar snap peas ( Pisum sativum var. macrocarpon Ser., cultivar ‘Sugar Daddy’) were harvested when mature (the seeds filled the hull without deforming it), immature (the seeds did not fill the hull) and over-mature (the seeds deformed the hull) and stored at 0°C for a period of 3 weeks. Sucrose made up the bulk of the total sugars in the seeds and levels increased markedly during storage of immature and mature seeds, whereas the overmature seeds showed no change. During storage, glucose level increased in immature seeds, remained the same in mature seeds and decreased in overmature seeds. Fructose level also increased in immature seeds and slightly increased in mature seeds, but was not present in overmature seeds. Before storage, hulls of immature samples contained less than half the amount of sucrose found in more mature hulls. However, the total sugar content of immature hulls increased during storage, whereas that of more hulls decreased. Glucose made up a large proportion of the total sugars in hulls and showed a significant increase during storage of immature samples. Seed percent dry weight (%DW) and percent alcohol insoluble solids (%AIS) increased with maturity and also during storage. Regardless of maturity %DW and %AIS of hulls decreased with storage. This suggests that the AIS material is broken down in the hulls and the nutrients are transported to the seed where, depending on pod maturity, they are added either to the sugars of AIS.
Blood Flow in Small Curved Tubes

Blood flow in small curved tubes is modeled by the two-fluid model where a relatively cell-free fluid layer envelops a fluid core of higher viscosity. The parameters in the model are successfully curve fitted to experimental data for straight tubes. The curved tube equations are then solved by perturbation theory. It was found that curvature in general lowers the tube resistance, but increases the shear stress near the inside wall.
Migration from plasticized films into foods. 1. Migration of di-(2-ethylhexyl)adipate from PVC films during home-use and microwave cooking.

Migration of di‐(2‐ethylhexyl)adipate (DEHA) into a diverse range of foods arising from the domestic use of plasticized PVC films has been determined using a stable isotope dilution GC/MS procedure. Aspects of home use reported in this study include the wrapping and covering of foods such as cheese, cooked meats, sandwiches, cakes, fresh fruit and vegetables; the use of films during food preparation such as marinading; covering during microwave reheating of previously prepared foods, and covering during microwave cooking. Contact between film and foods was for differing temperatures and times, representative of the range of conditions likely to be experienced in practice in the home. Migration increased with both the length of contact time and temperature of exposure, with the highest levels observed where there was a direct contact between the film and food, and where the latter had a high fat content on the contact surface. Highest levels of migration were observed for cheese, cooked meats, cakes and fo...
Nonlinear Meson Theory of Nuclear Forces. II. Nonlinearity in the Meson-Nucleon Coupling

The possibility of accounting for nuclear saturation by means of classical neutral scalar mesons that are coupled nonlinearly to the nucleons is investigated. It is shown that the interaction energy of an aggregate of nucleons is the same as in the usual linear theory if the nucleons are regarded as point sources. The theory does not, therefore, lead to saturation.
κ antagonist properties of buprenorphine in the shock titration procedure

Abstract Buprenorphine produced a dose-dependent antagonism of the selective κ opioid agonist U50,488 in squirrel monkeys responding under the shock titration procedure. In one group of four monkeys, 0.003–0.01 mg/kg buprenorphine produced dose-dependent rightward shifts in the individual U50,488 dose-effect curves and increased the A50 value for U50,488 more than 2-fold in each monkey. Furthermore, 0.01 mg/kg buprenorphine antagonized a maximally effective dose of U50, 488 in these monkeys. Buprenorphine (0.01–0.1 mg/kg) also produced rightward shifts in the group U50,488 dose-effect curve for a second group of three monkeys. Buprenorphine's antagonism of U50,488 was probably not a consequence of any μ opioid antagonist properties of buprenorphine in this procedure since (1) buprenorphine produced an inconsistent antagonism of the selective μ agonist fentanyl, and (2) the selective μ antagonist β-funaltrexamine did not antagonize U50,488. These results support the hypothesis that buprenorphine has κ antagonist activity in the shock titration procedure.
Draft Animal Power

“Some people who use draft animals joke that their motivation is that they start every time, unlike my tractor” (Mumma, 2008, p. 4). As we move into the second decade of the 21st century, more and ...
Successive cardinals with no partial square

We construct a model in which for all 1 ≤ n < ?, there is no stationary subset of $${\aleph_{n+1} \cap {\rm cof}(\aleph_n)}$$ ? n + 1 ? cof ( ? n ) which carries a partial square.
Injury and intimacy The queer transfiguration of racialized exclusion in Langston Hughes's translations of Nicolás Guillén

Langston Hughes's translations of Nicolas Guillen in Cuba Libre (1948) can aid in the theorization of the interrelation between race and eroticism. Hughes's versions actualize a space of exclusion that frustrates easy identification with either a priori African American or Afro-Cuban communities; this is a space wherein the very real hurts of racist oppression and the struggle between black subjects can be shared. There he brings into relief the trials and pains of black bodies by approximating their presence through lyric forms resembling speech and song. Their pained presence incorporates a kind of textual eroticism. This queer intimacy has the potential to seduce readers – white and black alike; it can draw readers into a similarly exilic state where they feel the injuries of the figures represented in the translations. In this way, Hughes implicitly levies upon his North American audience a shared responsibility for cultivating a new social world. Translation by black lyricists such as Hughes generate...
In Vivo Dynamics of Norepinephrine Release‐Reuptake in Multiple Terminal Field Regions of Rat Brain

Electrical stimulation of the ascending dorsal tegmental bundle of the locus ceruleus was used to elicit controlled release of norepinephrine. Real-time in vivo monitoring in the brains of urethane-anesthetized rats was observed with high speed chronocoulometry at rapidly responding carbon fiber electrodes. Using modeling similar to that developed for dopamine release, the electrochemical signals were characterized as the balance between norepinephrine release per electrical stimulation pulse and apparent Michaelis-Menten reuptake parameters. Stimulation produced simultaneous overflow release at all terminal fields examined. The release and reuptake characteristics varied considerably in different regions. If the parameters are normalized to endogenous concentration in the terminal fields, release but not reuptake correlates with innervation density in several regions. Stimulated release results in norepinephrine overflow and transport in most brain regions with half-lives of 1-3 s and overflow distances of 25-50 microns at most. A surprising exception occurs in the upper layers of cortex (cingulate and sensory) where half-lives may be in the 10s of seconds and spatial reach may be up to 100 microns. The uptake in the outer cortical layers appears to be minimal and comparable with only nonspecific reuptake.
SU‐E‐T‐165: Effects of Statistical Fluctuation in Monte Carlo Photon Beam Dose Calculation On Gamma Index Evaluation

Purpose: To systematically investigate the impact of the Monte Carlo (MC) statistical fluctuation on the gamma‐index test results. Methods: Firstly, we build a simplified model that theoretically demonstrates, to the first order approximation, the MC noise tends to overestimate gamma‐index values when existing in the reference dose and underestimate gamma‐index values when existing in the evaluation dose given the original gamma‐index is relatively large for the noise level. Secondly, we validate the theoretical conclusions using real clinical data: a IMRT prostate and a VMAT HN plan. We first conduct a base gamma‐index comparison between the non‐MC dose and the MC dose with zero noise level. We then compute average gamma‐index value, when the non‐MC dose is compared with the MC doses of different noise levels. Furthermore, the gamma passing rates are also reported for each comparison between the non‐MC dose and MC doses. Results: Our numerical experiments show that 1) when performing a gamma‐index test between an MC reference dose and a non‐MC evaluation dose, the average gamma‐index is overestimated and the passing rate decreases with the increase of noise levels in the reference dose; 2) when performing the test between a non‐MC reference dose and an MC evaluation dose, the average gamma‐index is underestimated when they are within the clinically relevant range and the passing rate increases with the increase of noise levels in the evaluation dose; 3) when performing a gamma‐index test between an MC reference dose and an MC evaluation dose, the passing rate is overestimated when the noise in the evaluation dose dominates, and underestimated when the noise in the reference dose dominates. Conclusion: Gamma‐index tests should be used with caution when comparing dose distributions computed with MC simulations.
The participation decision versus the level of participation in an environmental treaty: a spatial probit analysis

Abstract This paper represents treaty participation as a two-stage game, for which nations first decide whether or not to participate and then they choose their level of participation. The resulting subgame perfect equilibrium is used to derive a reduced-form equation for estimating and separating the influences of the variables at the two decision stages. This spatial probit equation forms the basis for a full-information maximum likelihood estimator that accounts for the simultaneity bias associated with public good spillins at both stages. When the procedure is applied to the Helsinki Protocol, we find that the strategic influence of a variable may drastically differ depending upon which stage is scrutinized.
Registration mark detection for electron-beam lithography: EL1 system

In electron-beam lithography for direct exposure of wafers for integrated circuit manufacturing, accurate registration is necessary to achieve the required pattern overlay. This paper examines elements that should be considered to optimize the registration mark detection process in an automatic registration system for an e-beam lithography tool such as IBM's EL1. Included is a section on the generation of the backscatter signals and the proper combination of these signals to reduce the detection uncertainty errors in a system with four backscatter detectors. Signals obtained from resist-coated marks with several vertical profiles are presented for illustration and comparison with the predicted results. Beam shot noise, resist effects, and other factors that affect the signal-to-noise ratio are discussed and some pattern overlay results from EL1 are given.
Kinetics and Mechanism of the Hydrogen Evolution Reaction on Titanium in Acidic Media

The effects of potential and pH on the rate of the hydrogen evolution reaction on zone-refined titanium have been determined in acidic sulfate and chloride media over the pH range of 0 to 4.0. In all cases, the cathodic Tafel slope is equal to -120 mV, i.e., (sigmaE/sigmalogexclamationi /SUB H/ ,infinityexclamation) /SUB pH/ = -2(2.303 RT/F). The reaction order with respect to proton activity, (-sigmalogexclamationi /SUB H/ ,infinityexclamation/sigmapH) /SUB E/ , exhibits a minimum value of 0.49 at pH = 1.83, and increases to limiting value of 1.0 with increasing or decreasing pH. A mechanism in agreement with the aforementioned observations has been proposed. The mechanism consists of two parallel paths for rate-determining proton discharge, one path involving the usual solvated proton and the other involving the adsorbed surface species (TiOH)/sup +/ /SUB ads/ , followed by the fast recombination reaction. Langmuir adsorption kinetics apply to the adsorbed hydrogen atoms. The proposed mechanism is consistent wit what is known concerning the effect of potential upon the rate of absorption of hydrogen by the metal. The mechanism is also consistent with the mechanism of active-state dissolution and passivation of titanium in acidic media.
Three-dimensional structure of DesVI from Streptomyces venezuelae: a sugar N,N-dimethyltransferase required for dTDP-desosamine biosynthesis.

d-Desosamine, or 3-(dimethylamino)-3,4,6-trideoxyglucose, is an unusual sugar found on the macrolide antibiotic erythromycin, and it has been shown to play a critical role in the biological activity of the drug. Desosamine is added to the parent aglycone via the action of a glycosyltransferase that utilizes dTDP-desosamine as its substrate. Six enzymes are required for the biosynthesis of dTDP-desosamine in Streptomyces venezuelae, with the last step catalyzed by DesVI, an N,N-dimethyltransferase. Here we describe the X-ray crystal structure determined to 2.0 A resolution of DesVI complexed with S-adenosylmethionine (SAM) and the substrate analogue UDP-benzene. Each subunit of the DesVI dimer contains a seven-stranded mixed β-sheet flanked on either side by α-helices. In addition to this major tertiary structural element, there is a four-stranded antiparallel β-sheet that provides the platform necessary for subunit−subunit assembly. On the basis of the UDP-benzene binding mode, the DesVI substrate, dTDP-3...
Bioassay of circulating luteinizing hormone in the rhesus monkey: comparison with radioimmunoassay during physiological changes.

The concentration ot biologically active LH in rhesus monkey (Macaca mulatta) serum was measured by a highly sensitive bioassay based upon testosterone production by dispersed rat interstitial cells. The sensitivity of the in vitro bioassay was equal to or higher than that of radioimmunoassay, with detection limits of 0.1 mlU of human menopausal gonadotropin (hMG) or 10 ng of a rhesus pituitary gonadotropin preparation (LER-1909–2). Parallel dose-response curves were obtained for hMG and rhesus monkey pituitary gonadotropin. The method permits bioassay of LH in 20–100 μl of serum from adult male monkeys, and from female monkeys during the follicular and luteal phases of the menstrual cycle. Bioactive LH concentrations could be assayed in 0.25 to 5 μl of serum from mid-cycle, postmenopausal, and castrated female monkeys. Serum LH was undetectable in two hypo-physectomized adult female monkeys and six intact immature animals, and was 13 ± 6 (SD) mlU/ml in adult male monkeys. In adult females, follicular pha...
Substrate binding and turnover by the highly specific I-PpoI endonuclease

Intron-encoded endonucleases are distinguished by their ability to catalyze the cleavage of double-stranded DNA with high specificity. I-PpoI endonuclease, an intron-encoded endonuclease from the slime mold Physarum polycephalum, is a small enzyme (2 × 20 kDa) that catalyzes the cleavage of a large asymmetric DNA sequence (15 base pairs). Here, the interactions of I-PpoI with its substrate were examined during both binding (in the absence of Mg2+) and catalysis (in the presence of Mg2+). Using circular permutation assays, I-PpoI was shown to bend its substrate by 38 ± 4° upon binding. Two independent methods, gel mobility shift assays and fluorescence polarization assays, revealed that I-PpoI binds tightly to its substrate. Values of Kd range from 3.3 to 112 nM, increasing with increasing NaCl concentration. Similar salt effects on the values of Km were observed during steady-state catalysis. At low salt concentrations, the value of kcat/Km for the cleavage of an oligonucleotide duplex approaches 108 M-1 ...
In-vitro activity of azithromycin on Chlamydia trachomatis infected, polarized human endometrial epithelial cells

The in-vitro activity of azithromycin on Chlamydia trachomatis infected human endometrial epithelial cells, both primary and transformed cells growing in a polarized and non-polarized orientation, was analyzed. Addition of azithromycin two hours after adsorption inoculation with continued exposure until 72 h gave an MIC90 and MBC90 of 0.063 and 0.5 mg/L, respectively. In addition, the MBC results were more pronounced in infected cells growing in a polarized orientation. Numerous small fluorescent 'spots' (presumed small abnormal inclusions) were visible in the infected cells exposed to MIC concentrations of azithromycin. Immuno-transmission electron microscopy examination revealed intracellular inclusions filled with chlamydial envelope ghosts. Since standard diagnostic antigen detection methods use anti-envelope antibodies, the aberrant envelope-filled inclusions might be interpreted as viable inclusions by fluorescent microscopy and result in high false positive readings. To simulate treatment of an infected patient, azithromycin was added at 18 h to infected cells containing many reticulate bodies and exposure continued for 54 h after which killing of chlamydiae was seen. The use of polarized human cells may offer a more relevant in-vitro model system for examining the efficacy of antimicrobial action.
Monitor peptide binding sites are expressed in the rat liver and small intestine.

Abstract 125 I-monitor peptide binding was performed using frozen sections of the rat liver and gut and visualized using autoradiography. Saturable binding was observed in unidentified single cells in the liver and in the mucosa of the small intestine. Epidermal growth factor (EGF) and GTPγS did not inhibit 125 I-monitor peptide binding indicating that the binding sites are not EGF receptors or G protein-coupled receptors. The liver binding site exhibited an affinity 3.7–4.4-fold higher than those in the small intestine. It has been established that intraluminal monitor peptide releases cholecystokinin from the small intestine. The present results indicate that monitor peptide may also have liver associated functions.
LSO/LYSO Crystals for Calorimeters in Future HEP Experiments

Because of their high stopping power (X 0 = 1.14 cm), fast (τ = 40 ns) bright (4 times BGO) scintillation with small temperature coefficient (−0.2%/°C) and superb radiation hardness, LSO/LYSO crystals are chosen to construct electromagnetic calorimeters (ECAL) of total absorption nature. One critical issue for this application is the light response uniformity (LRU) of long crystal bars with tapered geometry, which is affected by the non-uniform light yield along the crystal, the self-absorption and the optical focusing effect. Following a ray-tracing simulation study, an uniformization method was developed by roughening one side surface with LRU of better than 3% achieved. LSO/LYSO crystals are also proposed as the active material for a sampling ECAL for future HEP experiments in severe radiation environment. Preliminary designs with Pb or W absorber are described. Measurements of light collection efficiency (LCE) for prototype Shashlik cells with wavelength shifting fiber readout are presented. Future development on LSO/LYSO crystal based sampling ECAL is discussed.
The relationship between recreational gambling and substance abuse/dependence: Data from a nationally representative sample

Background Although recreational gambling is prevalent and co-occurs with substance abuse/dependence, few studies have investigated the relationship between the two.
Buckling of Soil-Surrounded Tubes

This paper describes a theoretical and experimental investigation of buckling of a tube surrounded by a soil in a circular symmetric configuration. The tube was failed by increasing the effective stress and the pore pressure acting on the tube. Results correlated well with the theory for buckling of an elastically supported tube. Further, the modulus of elastic soil support was shown to agree well with the modulus of resistance of the surrounding soil cylinder to uniform pressure applied at its inner boundary. Application of the results to practical situation indicated that the surrounding soil increases the buckling resistance of tubes by orders of magnitude over that of unsupported tubes. Hence, in reasonably stiff soil elastic buckling at stresses much below yield is a design criterion only for extremely thin-walled metal tubes.
The social ecology of resolving family conflict among West African immigrants in New York: a grounded theory approach.

The current study employs a grounded theory approach to examine West African immigrants’ resolution of parent–child conflict and intimate partner conflict. Data from 59 participants present an interactive social ecological framework, where a lack of resolution at one level results in attempts to resolve problems at higher levels. Four levels are identified within West African immigrants’ problem solving ecology, each with specific actors in positions of authority: individual/dyadic (parents and spouses), extended family (which includes distant relatives and relatives living in home countries), community leadership (non-family elders and religious leaders), and state authorities. From participants’ descriptions of family challenges emerged a picture of a social ecology in flux, with traditional, socially conservative modes of resolving family conflict transposed across migration into the more liberal and state-oriented familial context of the United States. This transposition results in a loss spiral for the traditional social ecology, differentially affecting individual actors within families. Implications for helping professionals working with new immigrant communities include identifying variability in openness to adapting structures that are not working well (e.g., patriarchal protection of abusive husbands) and supporting structures known to be associated with well being (e.g., collective monitoring of youth).
Childhood Stuttering: To Treat or Not to Treat

(1999). Childhood Stuttering: To Treat or Not to Treat. Advances in Speech Language Pathology: Vol. 1, No. 2, pp. 139-141.
A pyrene fluorescence technique and microchamber for measurement of oxygen consumption of single isolated axons.

Pyrene fluorescence is quenched by oxygen in an inverse and linear manner related to the partial pressure of O2 in solution. We have developed a microchamber for measuring QO2 of a single isolated axon, monitoring the change in fluorescence of a pyrene probe. The probe consists of a Spectra/Por dialysis hollow fiber filled with 2.5 mM pyrene in paraffin oil. The probe is inserted into a 1-mm-i.d. 2-cm-long quartz capillary tube with a freshly isolated crayfish medial giant axon. The capillary is mounted in an apparatus that forms an air- and water-tight seal except for a 0.2-mm-i.d. stainless steel tube at both ends permitting the exchange of solutions. An Olympus inverted microscope, equipped with epifluorescence optics and a 150-W xenon lamp, is used to view the preparation, generate the excitation light, and monitor the emitted fluorescence with a photomultiplier tube placed in the microscope TV port. A dichroic filter unit is utilized to select an excitation wavelength of 350 nm and collect emitted light above 420 nm. The signal is amplified with a Keithley 480 picoammeter and recorded on a strip chart. QO2 of isolated axons was 552 +/- 70 X 10(-6) mol O2/liter tissue X min. Following sequential treatment with 2 mM ouabain and 2 mM NaCN, QO2 decreased by 22 and 82%, respectively. These data are consistent with QO2 measurements of whole nerve cord made with a Clark electrode O2 monitor.(ABSTRACT TRUNCATED AT 250 WORDS)
Methods for pore size engineering in ZSM-5 zeolite

The desilicated form of the ZSM-5 was prepared by a process which involved the selective removal of silicon atoms from the parent sodium form zeolite in an aqueous basic solution of sodium carbonate. If the resulting material was activated at 700C, its pore size was larger than that of the parent zeolite. The sample is called DS for: Desilication and Stabilization. The desilication treatment has the effect of lowering the Si/Al ratio, while keeping the zeolite structure essentially unmodified. The silicate material which had been removed was determined to be in large proportion sodium orthosilicate. Ion-exchange of the Na-DZSM-5 with ammonium chloride gives us the more acidic form H-DZSM-5. An amount of 5 wt.% sodium orthosilicate is reinserted on the H-DZSM-5 zeolite and with a stepwise heating treatment to 700C for 16-18 hours, the pore size decreases to 4.6A. This process is termed DRS, which stands for: Desilication, Reinsertion and Stabilization. To get this pore narrowing, there is a reaction that occurs between the zeolite's and the orthosilicate's silanols during the thermal treatment. This reaction results from dehydroxylation and formation of siloxane bonds. Selective adsorptive tests with the BTX aromatics and catalytic runs performed with methanol at various reaction temperatures, confirm the enlargement due to the DS treatment, and the pore narrowing as the result of the DRS treatment. With the goal of better understanding the mechanism involved in the DRS process and to improve the success rate, we passed the sodium orthosilicate through an acid resin and then an amount of 8 wt.% of the resulting orthosilicic acid was reinserted into the H-DZSM-5. The sample was then activated to 700C for a period of 16-18 hours and a measure of the median pore size gave us 4.4A with an improved reproducibility. The reaction temperature between the zeolite's and the orthosilicic silanols was determined with the Differential Scanning Calorimetry/Thermal Gravimetric Analysis (DSC/TGA) instrument to be ca. 600C. The product of this reaction gives us the formation of new siloxane bonds which are responsible for pore narrowing. Selective adsorption tests with n-heptane and isooctane, catalytic runs performed with methanol at various reaction temperature, the determination of the constraint index and the internal space, confirmed the pore narrowing as the result of the DRS treatment.
Performance of Counterflow Microchannel Heat Exchangers Subjected to External Heat Transfer

This article analyzes the effect of external heat transfer on the thermal performance of counterflow microchannel heat exchangers. Equations for predicting the axial temperature and the effectiveness of both fluids as well as the heat transferred between the fluids, while operating under external heating or cooling conditions, are provided in this article. External heating may decrease and increase the effectiveness of the hot and cold fluids, respectively. External cooling may improve and degrade the effectiveness of the hot and cold fluids, respectively. For unbalanced flows, the thermal performance of the microchannel heat exchanger subjected to external heat transfer depends on the fluid with the lowest heat capacity. At a particular number of transfer units (NTU), the effectiveness of both the fluids increased with decrease in heat capacity ratio when the hot fluid had the lowest heat capacity. When the cold fluid had the lowest heat capacity, the effectiveness of both fluids increased with decrease ...
Allocation sequences of two processes sharing a resource

We study a Petri net model of a system composed of two processes sharing a resource. Conflicts may occur over the usage of the shared resource, thus making the system nondeterministic. Therefore, in the context of minimax algebra, it cannot be formulated as a linear system in order to compute its performance measures. However, if the sequence by which the resource is allocated to the two processes is known, we can transform the system into a decision-free net. For this system with an imposed constraint on the resource allocation frequencies, we show that the optimal allocation sequence is the most regular integer sequence satisfying that constraint. We also discuss the periodic behavior of this system under no constraints on the resource allocation frequencies. >
Optimum morphology and performance gains of organic solar cells

Morphology of light absorbing layer is known to dictate the power conversion efficiency of organic photovoltaic (OPV) cell. The innovation of bulk heterojunction (BH) led to significant improvement for exciton harvesting, but carrier recombination at the distributed interfaces and variability of performance have been persistent concerns. The purpose of this paper is to theoretically explore the efficiency-space of OPV as a function of the degree of randomness of its morphology and to optimize the BHJ morphology for the maximum efficiency. We use systematic numerical simulation of exciton/electron/hole transport to predict the efficiency and variability associated with various OPV morphologies. We find that while (1) the efficiency of random BHJ morphology can be close to optimal, (2) the significant variability associated with cells suggests reduced efficiency in a series-connected configuration. (3) We also find that a simple fully ordered structure may also not be optimum; instead a fin like geometry (Fig. 4) may improve efficiency. (4) We also analyze the effect of each transport parameters on the cell efficiency and show that under certain configuration of transport parameters, the long-abandoned PHJ structure may re-emerge as optimal geometry.
Unified compilation of Fortran 77D and 90D

We present a unified approach to compiling Fortran 77D and Fortran 90D programs for efficient execution of MIMD distributed-memory machines. The integrated Fortran D compiler relies on two key observations. First, array constructs may be scalarized into FORALL loops without loss of information. Second, loop fusion, partitioning, and sectioning optimizations are essential for both Fortran D dialects.
Amlodipine – not a significant contributor to clopidogrel non-response?

The current study by Li et al 1 examines the pharmacodynamic interaction of amlodipine and clopidogrel. Dual antiplatelet therapy with aspirin and clopidogrel is standard of care for patients with coronary stenting and acute coronary syndromes, although newer, more potent P2Y12 inhibitors such as prasugrel and ticagrelor have recently become available. Clopidogrel is a prodrug that is metabolised in a two-step process by cytochrome P450 (CYP) and esterases to its principal metabolites (figure 1).2 Large interpatient variability has been observed in pharmacodynamic studies of clopidogrel response and pharmacokinetic studies measuring active clopidogrel thiol metabolites. Among the CYP450 isoforms, CYP2C19, CYP3A4, CYP2C9 and CYP2B6 have been identified as being involved in the second step of 2-oxo clopidogrel metabolism and active thiol formation. A variety of esterases are thought to mediate inactivation of parent clopidogrel and metabolites, thus influencing the availability of active thiol metabolite and eventually the pharmacodynamic response to clopidogrel. The term ‘clopidogrel non-response’ has been used to describe persistent high ADP induced platelet reactivity during treatment with clopidogrel and has been defined by various ex vivo assays. Figure 1 Metabolism of clopidogrel by cytochrome P450 isoenzymes and esterases. The importance of individual CYP450 enzymes in clopidogrel metabolism to its active form has been illustrated by the finding that carriers of CYP2C19*2 polymorphisms who are treated with clopidogrel after coronary stenting are at increased risk of adverse thrombotic events.3 This enzyme is vulnerable to drug-drug interactions, as are other CYP450 isoforms involved in clopidogrel metabolism. Many drugs that are commonly prescribed to patients with coronary artery disease happen to interact with these enzymes. Statins, some of which are metabolised by CYP3A4, and proton pump inhibitors, which are often metabolised by CYP2C19 have received particular attention as concerns have surfaced regarding …
Detection of cracks in ceramic matrix composites based on surface temperature

Ceramic matrix composites are processed at high temperatures and experience significant residual thermal stresses upon cooling to room temperature. These stresses often result in matrix cracking prior to the application of external loads. Matrix cracks may also appear as a result of thermomechanical loading. It is important to detect these matrix cracks using a nondestructive technique. The method proposed in this paper is based on measurements of the surface temperature of a ceramic matrix material subjected to cyclic stresses. The elevated surface temperature is due to friction between the fibers and the matrix that occurs in the presence of bridging matrix cracks. The solution presents a relationship between surface temperature and matrix crack spacing that can be used to identify the extent of the damage.
Plant-Microbe Interactions: Life and Death at the Interface.

Interactions between microorganisms and plants have undoubtedly had major effects on the development of civilization since humans began to rely extensively on cultivated crops for food. Indeed, ancient chronicles of famines, plagues, and epidemics show that some of the more serious plant diseases, such as rusts, smuts, and mildews, were recognized soon af? ter the emergence of organized agriculture. Theophrastus (~371 to 287 bc) described disease symptoms on a number of plants used for food and the Romans paid tribute to appease the rust god Robigo. More recently, plant disease outbreaks have resulted in catastrophic crop failures that have triggered famines and caused major social change. The effects of such epidemics have been particularly devastating in situations such as the Irish potato famine of the 1840s, in which communities depended on a single crop as their primary food source. The potential for se? rious crop disease epidemics still persists today, as evidenced by recent outbreaks of Victoria blight of oats and southern corn leaf blight. These diseases result from agricultural practices that rely on monoculture crops?planting closely related crop species over wide geographical areas provides, in effect, a large Petri dish for the evolution of increasingly virulent patho? gen forms. In addition to causing food shortages, microbial interactions with plants can directly affect the health of humans and livestock. One notable example is ergot poisoning, caused by toxins in the fruiting bodies of the fungus Claviceps purpurea, which can contaminate rye flour. These toxins cause a frightening syndrome typified by hallucinations, burning sensations, miscarriages, gangrene, and, in severe cases, death. The affliction, known as St. Anthony's fire or Holy fire, was most prevalent in the Middle Ages; present day outbreaks are only prevented by the strict cultural and sanitary standards that are now applied in the regulation of grain sales. Further problems resulting from the presence of allergens, carcinogenic com? pounds, and various mycotoxins in moldy grain, peanuts, and animal feed have recently been shown to affect human health. For readers interested in more fundamental information, a broad coverage of plant pathology is provided in the text by
Did insect pollination cause increased seed plant diversity

The dominant paradigm for the disproportionate number of flowering plants is the unique coevolution that they underwent with pollinating insects. The theory underlying this biotic pollination hypothesis contradicts more generally accepted evolutionary theory. Furthermore, various lines of empirical evidence falsify the biotic pollination hypothesis: (a) several lineages of plants were insect pollinated – angiosperms, Gnetales, Bennettitales, Cheirolepidiaceae, Medullosales, and Cycadales – yet only the first four were ever diverse or underwent radiations; (b) the predicted rise in insect diversity, which was coupled with angiosperm radiation, does not appear in the fossil record; (c) the family Poaceae (grasses) are wind pollinated, yet are exceptionally diverse and species-rich; and (d) the family Formicidae (ants) were not pollinators, yet are exceptionally species-rich and ecologically dominant. I enumerate many alternate (and seldom investigated) hypotheses for these patterns of seed plant diversity, keeping in mind that although I show that insect pollination was neither a necessary nor sufficient condition for large numbers of species, it may have played a substantial role in both plant and insect speciation. Alternatively, existing theory regarding the biotic pollination hypothesis can be refined in an attempt to eliminate the aforementioned empirical anomalies and theoretical inconsistencies.  2001 The Linnean Society of London
Late Proterozoic plate tectonics and palaeogeography: a tale of two supercontinents, Rodinia and Pannotia

The plate tectonic and palaeogeographic history of the late Proterozoic is a tale of two supercontinents: Rodinia and Pannotia. Rodinia formed during the Grenville Event (c. 1100 Ma) and remained intact until its collision with the Congo continent (800-750 Ma). This collision closed the southern part of the Mozambique Seaway, and triggered the break-up of Rodinia. The Panthalassic Ocean opened as the supercontinent of Rodinia split into a northern half (East Gondwana, Cathyasia and Cimmeria) and a southern half (Laurentia, Amazonia- NW Africa, Baltica, and Siberia). Over the next 150 Ma, North Rodinia rotated counter-clockwise over the North Pole, while South Rodinia rotated clockwise across the South Pole. In the latest Precambrian (650-550 Ma), the three Neoproterozoic continents - North Rodinia, South Rodinia and the Congo continents - collided during the Pan-Africa Event forming the second Neoproterozoic superconti- nent, Pannotia (Greater Gondwanaland). Pan-African mountain building and the fall in sea level associated with the assembly of Pannotia may have triggered the extreme Ice House conditions that characterize the middle and late Neoproterozoic. Although the palaeogeographic maps pre- sented here do not prohibit a Snowball Earth, the mapped extent of Neoproterozoic ice sheets favour a bipolar Ice House World with a broad expanse of ocean at the equator. Soon after it was assembled (c. 560 Ma), Pannotia broke apart into the four principal Palaeozoic continents: Lauren- tia (North America), Baltica (northern Europe), Siberia and Gondwana. The amalgamation and sub- sequent break-up of Pannotia may have triggered the 'Cambrian Explosion'. The first economically important accumulations of hydrocarbons are from Neoproterozoic sources. The two major source rocks of this age (Nepa of Siberia and Huqf of Oman) occur in association with massive Neoprotero- zoic evaporite deposits and in the warm equatorial- subtropical belt, within 308 of the equator. In this report we tell the tale of two late Precambrian supercontinents: Rodinia and Pannotia. We describe the configuration of continents that comprised Rodinia and Pannotia, outline a plausible history of their formation and break-up, reconstruct long- gone mountain ranges and seaways, and infer the location of ancient plate boundaries. The Rodinia -Pannotia model that we construct can be used as a framework to understand better the deposi- tional environments of late Precambrian oil source rocks and the history of late Precambrian global climate change.
Computer Use by Older Adults: A Review of the Literature

Background: Patient engagement standards promoted by the US government’s EHR Incentive Program promote patient interaction with the healthcare system using health information technology (HIT) such as patient portals and secure messaging, yet older adults may be ill equipped to participate in this way. This integrative literature review sought to identify research on the use of HIT by older adults and to examine the state of the science in this area. Methods: 14 studies published in peer-reviewed, English-language journals between 2007 and 2013, focusing on the computer/internet usage patterns of US adults aged >65 were included when they included a measurement of the participant’s health literacy. Articles were read and examined multiple times using matrixes and data displays to enhance analysis. A level of knowledge label and a determination of congruence were applied to each study to assess the quality of studies and state of the science in this area. Results: A variety of designs were used (1 experimental, 1 quasi-experimental, 1 qualitative, 11 nonexperimental) in various community settings. Health literacy was defined in a variety of ways with multiple instruments. Computer/internet users are younger, healthier, and more educated than non-users. Only half of adults >65 and less than 34% of users >75 used the computer. Non-Hispanic Whites were more likely than any other ethnic/racial group to use HIT. Use is enhanced with social support and reduced by limitations in computer skills, health literacy, physical condition, and cognition. Older adults used the computer/internet primarily to send emails. Interventions promoting HIT to improve health outcomes have low rates of use. The state of the science remains at a descriptive exploratory level. Conclusion: Older adults are less likely than other age cohorts to access the internet for health information despite the fact that they bear the greatest burden of chronic disease and limited health literacy. There are significant gaps in our knowledge regarding HIT use in this population, making the success of national programs aimed at engaging patients through its use questionable.
Use of a catheter limiter during intermittent catheterization

We report on the use of a new device, the catheter limiter, to facilitate clean intermittent catheterization. The device limits the length of catheter entering the urethra. This provides a means to reduce the risk of mechanical injury and perforation, minimizes incomplete emptying, and improves safety and patient acceptance of intermittent catheterization.
Two-foci, bendable mirrors for the ALS MAESTRO beamline: design and metrology characterization and optimal tuning of the mirror benders

MAESTRO, the Microscopic and Electronic STRucture Observatory, currently under construction at the Advanced Light Source (ALS), will be a world premier facility for the study of electronic and structural properties of in situ grown crystals. The new facility will be comprised of several end-stations, including angle-resolved photoemission spectroscopy, μARPES and nARPES end-stations, and a photoemission electron microscope combined with a lowenergy electron microscope (PEEM/LEEM). Redirection of the x-ray beam between the μARPES and PEEM/LEEM end-stations, which are longitudinally separated by 2.5 meters, uses a system of two bendable mirrors, placed in Kirkpatrick-Baez configuration designed for two foci. Here we present the details of the mirrors’ design and report on the characterization of the mirrors carried out at the ALS X-ray optical laboratory (XROL). Optimal tuning and calibration of the mirrors was performed using a technique recently developed at the OML [Opt. Eng. 48(8), 083601 (2009)]. The technique is based on regression analysis of surface slope data obtained with a long trace profiler (LTP). We provide results of tests of temporal and temperature stabilities of the shape of the mirrors. High reliability of the optical metrology with the mirrors has become possible due to a modification of the tuning procedure described in the present article. The modification allows accounting for the gravity sag effect, as well as the LTP systematic error in measurements with significantly curved x-ray optics.
The role of teacher instructional practices in student collaboration

Abstract Prior research on collaborative learning identifies student behaviors that significantly predict student achievement, such as giving explanations of one’s thinking. Less often studied is the role of teachers’ instructional practices in collaboration among students. This article investigates the extent to which teachers engage in practices that support students’ explanations of their thinking, and how these teacher practices might be related to the nature of explanations that students give when asked by the teacher to collaborate with each other. The teachers observed here, all of whom received specific instruction in eliciting the details of student thinking, varied significantly in the extent to which they asked students to elaborate on their suggestions. This variation corresponded to variation across classrooms in the nature and extent of student explanations during collaborative conversations and to differences in student achievement.
An accurate stereo correspondence method for textured scenes using improved power cepstrum techniques

A qualitative analysis of the effects of noise, foreshortening, and photometric variations on cepstral correspondence methods is presented. A modified approach that is less sensitive to these effects is developed, and analytical arguments for its robustness are given. The performance of the improved method is experimentally verified on real data. >
On the distribution of mean radiative cooling at the top of a stratocumulus-capped mixed layer

The fraction, r, of the net in-cloud radiative flux difference existing within the mean capping inversion of a stratocumulus-topped mixed layer is calculated, assuming an exponential diminution of radiative flux below local cloud-top height. Its dependence upon hoλ and Δh/ho is presented, where ho is the depth of the well-mixed portion of the boundary layer, λ is the radiative extinction length, and Δh is the thickness of the mean capping inversion, or entrainment zone, within the context of ensemble averaging or horizontal averaging. the calculation makes use of laboratory observations on the distribution of mixed-layer matter within the entrainment zone of a convectively mixed layer. the fraction r is shown to vary widely between its limits of 0 and 1 and under different configurations of stratocumulus mixed layers. For a given net radiative flux at the top of the cloud, it is shown that changes in λ and r have a modest effect upon the buoyancy flux profile and a strong effect upon the entrainment rate. Buoyant production of turbulence within the well-mixed layer is found to be maximized when r lies in the vicinity of 0.3.