cssi/SciSciGPT-SciSciNet huggingface dataset:
Evidence for peptide transport across microsomal membranes

Antigenic peptides bound to class I molecules of the major histocompatibility complex (MHC) are recognized by T-cell receptors during development of an antiviral immune response. T cells respond to peptides derived from cytoplasmic viral proteins as well as viral membrane proteins, indicating that a pathway exists for the transport of proteins or peptides from the cytosol into the compartment(s) where the MHC class I molecules assemble. To investigate this pathway, we have developed an in vitro assay for the transport of peptides into microsomal vesicles. This assay provides evidence for the transport of chemically synthesized peptides (13-21 amino acids) containing N-linked glycosylation acceptor sequences, which serve as glycosylation substrates. Their transport results in depletion of the pool of available dolichol high-mannose oligosaccharides in the lumen of the microsomal vesicles. We have observed transport of peptides derived from antigenic human immunodeficiency virus gag and influenza B nucleoprotein sequences, but transport of a third randomly selected peptide was not detected, suggesting specificity of the transport process. We were not able to demonstrate ATP dependence of this peptide transport process by using apyrase and an ATPase inhibitor. This result was unexpected in light of the recent identification of MHC-linked genes with homology to ATP-binding cassette transporters, which have been proposed to mediate peptide transport.
The use of morphological knowledge in spelling derived forms by learning-disabled and normal students.

Currently popular systems for classification of spelling words or errors emphasize the learning of phoneme-grapheme correspondences and memorization of irregular words, but do not take into account the morphophonemic nature of the English language. This study is based on the premise that knowledge of the morphological rules of derivational morphology is acquired developmentally and is related to the spelling abilities of both normal and learning-disabled (LD) students. It addresses three issues: 1) how the learning of derivational morphology and the spelling of derived words by LD students compares to that of normal students; 2) whether LD students learn derived forms rulefully; and 3) the extent to which LD and normal students use knowledge of relationships between base and derived forms to spell derived words (e.g. “magic” and “magician”). The results showed that LD ninth graders’ knowledge of derivational morphology was equivalent to that of normal sixth graders, following similar patterns of mastery of orthographic and phonological rules, but that their spelling of derived forms was equivalent to that of the fourth graders. Thus, they know more about derivational morphology than they use in spelling. In addition, they were significantly more apt to spell derived words as whole words, without regard for morphemic structure, than even the fourth graders. Nonetheless, most of the LD spelling errors were phonetically acceptable, suggesting that their misspellings cannot be attributed primarily to poor knowledge of phoneme-grapheme correspondences.
Nonexistence of Riemann solutions for a quadratic model deriving from petroleum engineering

The study presented in this work shows that the viscous profile entropy criterion is too selective in reducing the number of solutions to guarantee existence of stable weak self-similar Riemann solutions to conservation laws. This result is shown on a particular quadratic model derived from the three-phase flow equations used in petroleum engineering. The viscosity matrix considered in this work derives from capillary pressures. The Riemann initial data are hyperbolic and correspond to a Lax 1-shock that does not admit a viscous profile. The nonexistence of a profile in this example is due to the presence of a limit cycle in the vector field associated with the viscous profile entropy criterion.To establish the main result of this work, a complete list of possibilities that could lead to a solution, is examined. This list includes solutions that consist of only classical waves and the solutions that contain at least one nonclassical (shock) wave. The construction of solutions breaks down because either the shock waves do not satisfy the viscous entropy criterion or the speeds of the waves that comprise a solution are decreasing. To the author's knowledge, this is the first result on nonexistence of stable solutions for models that allow nonclassical (transitional) shock waves.The results presented in this paper are a combination of analytical and numerical work. The theoretical ideas and techniques derive from the bifurcation theory of vector fields and the theory of weak solutions of conservation laws. These are combined with numerical results when no theory is available.
Extracellular ATP signaling in plants

Extracellular adenosine-5'-triphosphate (ATP) induces a number of cellular responses in plants and animals. Some of the molecular components for purinergic signaling in animal cells appear to be lacking in plant cells, although some cellular responses are similar in both systems [e.g. increased levels of cytosolic free calcium, nitric oxide (NO), and reactive oxygen species (ROS)]. The purpose of this review is to compare and contrast purinergic signaling mechanisms in animal and plant cells. This comparison will aid our overall understanding of plant physiology and also provide details of the general fundamentals of extracellular ATP signaling in eukaryotes.
Defoliation and the war on drugs in Putumayo, Colombia

Analysis of three Landsat Enhanced Thematic Mapper Plus (ETM+) images of the Putumayo region of Colombia, one of the primary regions of coca production in Colombia, demonstrated that aerial spraying of defoliants under the US ‘Plan Colombia’ programme impacted broad swaths of the landscape and had the unintended consequence of defoliating contiguous and interspersed native plant and food crop parcels. Using fractional coverage, field data collections and a hybrid classification, 106 178 ha of impacted land were found, compared with the United Nations Drug Control Program reported reduction in coca of 71 891 ha, an unexplained difference of 34 287 ha. The complex spatial organization of the Colombian coca‐producing landscape appeared to confound the spraying of defoliants, and as demonstrated here, many non‐coca land cover classes have been affected adversely.
GaAs MESFET For High-Speed Optical Detection

The microwave, low-noise GaAs-metal-semiconductor, field-effect transistor (MESFET) has a cutoff frequency higher than 80 GHz and possesses a good optical responsiveness over a very wide spectral range, from visible to near-infrared wavelengths. The drain-current variation of the MESFET is proportional to the input optic intensity. If the light is modulated, MESFET detects the high-speed subcarrier. Besides the low-noise and amplification-gain advantages, the MESFET photodetector operates at a low bias voltage, normally, below 6 V. The common-gate configuration at zero drain voltage also can function in a photocapacitive mode in which the capacitance changes with the change in polarized light intensity. The S-parameter of the device has been characterized up to Ku-band. The high-frequency optical receiver is ready to be designed and optimized using this charaterization. For high-speed fiber-optic communications, the monolithic receiver, the ILD driver, and the low-cost repeater all can be fabricated by using the MESFET's.
The Multiverse of Inquiry: Introduction to the Special Issue on “Dementia Care and Chinese Culture”

We organized this special issue for several reasons. Among them are two alarming facts: China has the largest aging population in the world and providing care to its more than ten million elders suffering from Alzheimer’s disease is becoming a significant public health threat and challenge. But we also find “Dementia Care and Chinese Culture” an intriguing topic because it reinforces a common view that the Chinese case challenges what we believe we already know. Moreover, no doubt what we learn will soon change our current understanding. We know for sure, based on research in the past 30 years, that dementia caregiving, regardless of geographical, educational, and socioeconomic differences, causes physical, emotional, and financial burdens to many caregiving families. What we do not know is how dementia care is and should be provided in a transitioning society. During this transition, traditional, family-based care for elders with chronic health problems and functional limitations is being tremendously challenged by a new, rapidly urbanizing and market-centered society; emerging institution-based care remains limited due to various financial, cultural, and social constraints. We also do not know how to connect what we have learned mainly from Western societies with Chinese culture. How do we blend dementia caregiver burdens, theories and measures of psychological distress, and intervention strategies and models with the emerging understanding of Chinese values, coping styles, and resources with which people influenced by Chinese cultures engage in dementia care tasks? Perhaps, a simple way to enter a quest for the unknown is to sort through what we believe we already know.
Effects of hydroxyflutamide in the medial preoptic area or lateral septum on reproductive behaviors in male rats

We examined whether androgen receptors in the medial preoptic area (MPOA) and lateral septum (LS) are required for the expression of copulation and sexual motivation. Castrated males received testosterone-filled silastic capsules to restore behavior, and were implanted with the antiandrogen hydroxyflutamide (OHF) or blank cannulae. One group was implanted in either the anteroventral MPOA or LS (ANT group). Another group was implanted in the posterodorsal MPOA or LS (POST group). Copulation was tested on days 2, 6, 10, and 14 of OHF exposure; partner preference, a measure of sexual motivation, was tested on day 15. The results showed that sexual behavior was significantly suppressed by OHF in the MPOA of the ANT group, but not the POST group. However, sexual motivation was significantly reduced by OHF in the MPOA of the POST group, but not the ANT group. In the LS, OHF had no effect on sexual behavior and partner preference regardless of implant site. The data suggest site specificity within the MPOA for androgen receptor activation of male reproductive behaviors.
A refined definition of structure in teaching

More on structure in teaching. Will the order of presentation of material influence production of logical relationships?
Catalytic Activation of Carbon Monoxide on Metal Surfaces

Interest in carbon monoxide has increased dramatically during the past decade. This is due primarily to a new interest in energy resources other than natural gas and petroleum resources which include coal, oil shale, and heavy residua. In any process which involves gasification to convert these hydrogen-deficient materials to hydrocarbons or other organic compounds, CO is one of the principal products of the gasification step, and its subsequent hydrogenation to form the required final products is of extreme importance. It is thermodynamically possible to produce methane as SNG, hydrocarbon liquids as fuels, and alcohols and olefins as chemical intermediates — the major problem is the selectiveproduction of the desired product. During the overall conversion process, the reaction between CO and water is important, viathe water gas shift reaction, not only because it is used to adjust the H2/CO ratio in the gas stream between the gasifier and the reactor, but also because H2O is a by-product of the CO hydrogenation reaction and can react with unconsumed CO in the syngas reactor to form CO2.
8 Using pseudorotation as a reaction coordinate in free energy simulations of nucleic acids

Backbone sugar groups are central components of nucleic acids. The conformations of the ribose/deoxyribose can be elegantly described using the concept of pseudorotation (Altona and Sundaralingam, 1972), and are dominated by the C2′- and C3′-endo conformers. The free energy barrier of the transition between these two major puckering modes can be probed by NMR relaxation experiments (Johnson and Hoogstraten, 2008), but an atomic picture of the transition path per se is only available for several truncated nucleoside analogues (Brameld & Goddard III, 1999). Here, we implemented a new free energy simulation method for Molecular Dynamics simulations using pseudorotation as the reaction coordinate (Cremer and Pople, 1975). This allowed us to compute the free energy landscape of a complete pseudorotation cycle. The free energy landscape revealed not only the relative stability of C2′- and C3′-endo conformers, but also the main transition path and its free energy barrier. As a validation of our new approach, we ...
Efficacy of the Straight endorectal pull-through in the management of familial adenomatous polyposis—A 16-year experience

From 1979 to 1995, 27 patients who had familial adenomatous polyposis (FAP) were treated at the authors' institution. Most patients (n = 23) presented as a result of a previous family history of FAP. Eighteen patients presented with symptomatic colonic disease that included bloody stools (n = 14), diarrhea (n = 10), and abdominal pain (n = 6). Treatment consisted of a total colectomy, rectal mucosectomy, and straight endorectal pull-through (ERPT) in 26 of 27 patients. One patient preferred to undergo an ileoanal J pouch reconstruction. A temporary diverting loop ileostomy was performed in 25 patients and closed at an average of 100 days after the ERPT. Follow-up has been achieved in 100% of the patients and ranges from 6 to 182 months with an average of 48 months. Postoperative complications included partial bowel obstruction (two patients, one requiring enterolysis); and mild pouchitis (one patient). Two of the 27 patients required proctectomy and permanent ileostomy procedures, one for rectal cancer that was present microscopically in the initial rectal specimen from the ERPT and the other because of recurrent anastomotic complications. No patient required revision of the straight pull-through to a pouch or takedown of the pull-through as a result of persistent diarrhea or dissatisfaction. All of the patients are continent, and 80% deny any soiling during bouts of gastroenteritis. The mean number of bowel movements reported was 10 per day at the first postoperative clinic visit with a gradual decreased to six per day after 2 years. Initial use of bulking (62%) and antimotility agents (88%) decreased significantly over the course of follow-up to 29% and 67%, respectively at the most recent follow-up (average, 48 months) of each patient. Pelvic sepsis, which occurs in 8% of most series of patients who have pouches, did not occur in any of our patients. Pouchitis, a common complication with pouches (23%), occurred in only one of the patients and was mild and easily treated medically. This series demonstrates that total colectomy with rectal mucosectomy and straight ERPT eliminates the risk of colorectal cancer and achieves continence with a low complication rate and excellent functional results and patient satisfaction.
A Musical Note

Frequent references to musical terms in Barthes's writings since 1970 suggest a progression beyond a standard semiological inquiry. A text on the «grain» of the voice, another on musica practica, and a third on Romantic song develop a model of figuration Barthes explores actively in the Fragments d'un discours amoureux (A Lover's Discourse) and La Chambre claire. This article is available in Studies in 20th Century Literature: http://newprairiepress.org/sttcl/vol5/iss2/10
Electronically stimulated adsorbate dissociation in the presence of an electronegative coadsorbate: (NO2+O) on Pt(111).

The effects of an electronegative coadsorbate on the stimulated dissociation of a chemisorbed molecule are investigated using state-resolved laser-ionization spectroscopy of those dissociation fragments which leave the surface. Specifically, we examine the NO({sup 2}{Pi}{sub {Omega}=1/2,3/2}) and O({sup 3}{ital P}{sub {ital J}}) fragment energies and yields resulting from electron- (6--350 eV) stimulated dissociation of chemisorbed NO{sub 2} as a function of preadsorbed atomic O coverage. The most dramatic effect associated with O coverage (up to {Theta}{sub O}=0.75 monolayer) is a large (a factor of 26) enhancement in the specific NO{sub 2} dissociation yield. There is also an O-induced narrowing of the translational energy distributions and a decrease in both the rotational and vibrational energy of the NO fragment. The dissociation threshold of {similar to}10 eV, together with lifetime arguments, suggest that the dominant excitation(s) are shallow-valence two-hole excitations. The above observations can be understood in terms of reduced substrate charge-transfer screening of these excitations. In addition, we observe a distinct propensity ({gt}4:1 at low {ital J}) for populating the upper ({Omega}=3/2) over the lower ({Omega}=1/2) level of the spin-orbit-split NO({sup 2}{Pi}{sub {Omega}}) ground state, whereas the spin-orbit population of the O({sup 3}{ital P}{sub {ital J}}) fragment is statistical (2{ital J}+1) withinmore » experimental error. The O({sup 3}{ital P}{sub {ital J}}) yield derives from dissociation of nitro-bound NO{sub 2} (N end down); no O({sup 3}{ital P}{sub {ital J}}) yield can be associated with side-bonded NO{sub 2}.« less
Equation of State Measurements at Ultra-High Pressures on the Sandiaz Accelerator

Summary form only given. A method has been developed to launch macroscopic flyer plates using the intense magnetic pressure produced by the Sandia Z accelerator. The accelerator is capable of producing >20 MA current pulses with ~200 ns rise-time into a short circuit load, generating intense magnetic fields within the anode cathode (AK) gap. The resulting Lorentz force enables the Z accelerator to be used very effectively in accelerating plates to ultra-high velocity. These experiments have been directed toward highly accurate dynamic material studies. In particular, emphasis has been placed on the launching of planar, solid density flyer plates to velocities exceeding 30 km/s for use in equation of state (EOS) studies at high-pressure. Velocities up to 34 km/s have been obtained with aluminum flyer plates several mm in lateral dimensions and a few hundred microns in thickness, resulting in constant pressure drive times up to ~30 ns in plate impact, shock wave experiments. Initial experiments were performed on aluminum, a widely studied metal, to validate the technique for use in high-pressure EOS experiments. Highly accurate, absolute Hugoniot measurements of aluminum have been obtained in the pressure range of 1-12 Mbar. Velocity interferometry (VISAR) was used to monitor the velocity of the aluminum flyer plate from launch to impact. The resulting shock speed was obtained from shock break out measurements of stepped targets. Accuracy of the measurements are ~1-2% in both shock and particle speed. This technique has also been used to perform high-pressure shock and release experiments. Direct impact experiments were performed on a low shock impedance, 200 mg/cc silica aerogel to determine the aerogel Hugoniot in the pressure range of ~30-150 GPa. Release experiments were then performed in which the aerogel was mounted onto an aluminum base plate, and the initial shock in the base plate was transmitted to the aerogel sample. In this way release states on release adiabats of aluminum from ~240-830 GPa states on the principal Hugoniot were ascertained. The results were compared to several EOS models for aluminum, and a rigorous statistical analysis was performed. The statistical analysis enabled the suitability of these various models in describing the release response of hot, liquid states to be determined. This study enhances our understanding of the release response of aluminum for high-pressure states on the Hugoniot and lends confidence to the use of aluminum as a standard material in impedance matching experiments
Chelating Self-Assembled Monolayers on Gold Generated from Spiroalkanedithiols

The formation of self-assembled monolayers (SAMs) on gold from the adsorption of a series of specifically designed 2,2-dialkylpropanedithiol derivatives, [CH3(CH2)n]2C[CH2SH]2 where n = 0, 3, 7, and 11−15, is reported. The SAMs were characterized by optical ellipsometry, contact angle goniometry, and polarization modulation infrared reflection absorption spectroscopy. These data, when compared to those collected on SAMs generated from normal alkanethiols (CH3(CH2)mSH) of similar chain length, suggest that the new SAMs are highly oriented and well packed. They exhibit, however, slightly less crystallinity than their alkanethiolate-based analogues. A preliminary description of the kinetics of adsorption and desorption of these new SAMs is presented.
Analysis of an arbitrary shaped guide bearing subject to normal oscillation and translation of a plate

Abstract An analytical solution for a two-dimensional arbitrarily shaped guide bearing under finite amplitude transverse vibration and translation of a plate is presented. The solution technique uses the method of averaged inertia and a perturbation method on the Navier-Stokes equations to predict the bearing load and phase. Solutions to the illustrative problem of a plane inclined thrust bearing under transverse vibration and translation of a plate are used to illustrate properties of the solutions. Increasing oscillation amplitude causes asymmetry in the bearing load. For a bearing tilted at small inclination angles a smaller Strouhal number (higher translation speed) is required to prevent suction from occurring during transverse vibration. Predictions of the occurrence of suction by lubrication theory can be significantly in error. Inertia-induced phase lead of the bearing load with respect to the lubrication solution increases with bearing inclination and approaches 90° as the squeeze Reynolds number Re s increases.
Neurophychological prognosis and clinical recovery

Abstract This report examines prognostic implications of neuropsychological deficit for clinical symptomatic improvement. Neuropsychological performance levels are related to the Brief Psychiatric Rating Scale thinking disturbance, paranoid disturbance, withdrawal/retardation, and anxiety/depression scales at hospital admission and discharge in 68 schizophrenic and psychotic and nonpsychotic mood disorder patients. Findings indicate a relationship between neurocognitive deficit and thinking disturbance at admission; however, neuropsychological impairment predicts blunted affect/emotional withdrawal at discharge, after the acute psychopathology resolves. Neuropsychological deficit is nonspecific, occuring across a broad range of cognitive-perceptual functions. These data suggest that neuropsychological dysfunction may be prognostic of a more chronic residual disorder in both schizophrenia and major psychotic and nonpsychotic mood disorder syndromes.
Spatial and temporal particle distributions in a laser generated plume

Abstract Two new techniques for characterizing particles generated in transient vaporization events are described. Acousto-optical deflection allows temporal and spatial information to be obtained with good resolution. In a transmission mode of observation, reliable particle densities are obtained for copper vaporized by a laser. The copper particles both absorb and scatter the test radiation. In the scattering mode, polarization ratios can be obtained by simultaneous measurements using two photomultiplier tubes. Such data can be used to determine particle sizes by comparing with the appropriate theoretical calculations.
Hydrogen production from methane hydrate with sequestering of carbon dioxide

Methane hydrate exists in large amounts in certain locations, in sea sediments and the geological structures below them and below artic regions permafrost, at low temperature and high pressure. It has recently been shown that there are suitable methods for producing methane, perhaps on a floating platform. There it could be reformed in an endothermic process to produce hydrogen and carbon dioxide. Some of the methane could be used to provide heat energy for a power plant on the platform to provide all needed power and support for the reforming process. After separation, hydrogen is the valuable and transportable product. All carbon dioxide produced on the platform could be separated from other gases and then sequestered, in one of several possible forms. In this way, hydrogen could be made available without the release of carbon dioxide to the atmosphere and the hydrogen could be an enabling step toward a world hydrogen economy, free of particles and carbon dioxide pollution.
Morphologic and Functional Characteristics of Alveolar Macrophages Following Cryopreservation

Cryopreservation of nucleated blood and bone marrow mononuclear cells has been used both to preserve such cells for clinical, diagnostic, or research use and to climinate them as passengers in frozen tissue destined for transplantation. Although techniques for macrophage and monocyte cryopreservation have been described, little work has been done on the functional state of these cells following frozen storage. Using rabbit alveolar macrophages (AM), we have shown that AM can be frozen, stored, and recovered without morphologic changes. Furthermore, freshly isolated and cryopreserved AM do not differ in their adherence characteristics or the organization of their actin cytoskeleton. Cryopreserved normal AM also retained inducible functions such as superoxide anion (O2) release and production of tumor necrosis factor (TNF) and interleukin-1 (IL-1). In order to further define the effects of cryopreservation on macrophage biology, we have also frozen macrophages which have been primed in vitro, and have demonstrated that the primed state remains at prefreezing levels after thawing and subsequent analysis. These data help define the effects of cryopreservation on cell function and establish parameters for the clinical and experimental evaluation of cryopreserved mononuclear phagocytes.
MONILINIA AND RHIZOPUS DECAY CONTROL DURING CONTROLLED RIPENING OF FREESTONE PEACHES FOR CANNING

— Decay was controlled when freestone peach fruit, harvested at various stages of maturity ranging from green to straw-color, were dipped in 50% 2,6-dichloro-4-nitroaniline (DCNA) at 1–1/2 and 4 lb/100 gal water and ripened for 5–17 days at 20°C and 90% R.H. Treated fruit had less than 10% decay while untreated fruit developed as much as 61% decay during this period. Regardless of treatment, straw-blush and full-blush fruit held for only 3 days did not develop decay. The most commonly occurring fungus pathogens, Monilinia fructicola and Rhizopus stolonifer, were controlled with these treatments. Postharvest DCNA plus captan dip treatments gave more effective decay control than from preharvest field sprays. Concentrations of DCNA or DCNA plus captan required for Monilinia decay control, suggested by preliminary laboratory tests on fruit, were verified by these commercial-size experiments.
A distinct, Na+-dependent glycine transport system in avian small intestine.

Abstract The intestinal absorption of glycine in the chicken has been studied by a tissue-accumulation procedure. Glycine entry is dependent upon Na + and is inhibited by anaerobiosis. By a kinetic test it has been shown that glycine is absorbed at a site different from the neutral (methionine) transport site previously characterized in this species. The glycine site has highest affinity for glycine, alanine, and other neutral amino acids, in that order. The order of affinities for the methionine site is: nonpolar, neutral amino acids>alanine>glycine. For the glycine site, the affinities of neutral amino acids are about one order of magnitude smaller than for the methionine site. However, like the methionine site preference for l -amino acids is seen, and acidic and basic amino acids have little or no affinity. Additionally, requirements are noted for an α-hydrogen atom and for a free α-amino group; substrates such as α-aminoisobutyric acid, proline, hydroxyproline, sarcosine and β-alanine do not interfere with glycine entry. Glycine, when used as a test inhibitor, has little influence on the absorptions of glutamic acid, lysine, alanine, or proline. The shapes of the time courses of glycine and methionine uptake are similar, and both amino acids have Q 10 values of about 1.7.
Categorizing interference in real robot experiments

Physical interference between robots happens when robots try to occupy the same region. In multi-robot experiments, interference between robots has been found to negatively impact performance. In addition, simulations do not always accurately predict real robot performance. So, we study the effects of unmodeled factors, such as interference, on the difference between real and simulated experiments. We believe that it is beneficial to understand the categorization of robot interference. Therefore, we examine different forms of interference in real robot experiments in order to set a basis for an interference model in simulation. We show that interference can be broken into categories which have discrete characteristics that affect robot performance differently in various environments.
Integral representations of particular integrals of a class of inhomogeneous linear ordinary differential equations

A method of obtaining integral representations of particular integrals of a class of inhomogeneous second‐order linear ordinary differential equations is presented. The integrands of the representations are exp[F (z;t)], where F (z;t) =z2a (t)+zb (t)+c (t), z is the independent variable of the differential equation, and a, b, and c are initially unspecified functions of the variable of integration, t. The lower limit of the contours of integration is zero. The upper limits of integration and the contours along which the integral is taken are initially unspecified. In the general class of inhomogeneous differential equations considered, the coefficients of the dependent variable and its derivatives are polynomials in z with complex constants and the homogeneous term is exp(k2z2+k1z+k0), where the kn are complex constants. One imposes the conditions that the application of the homogeneous operator to the assumed form of integral representation give the integral of −∂F/∂t, that exp[F (z;0)] be equal to the i...
Surprising consequences of the tendency of pepsin to catalyze condensation reactions between small peptides.

Abstract Pepsin catalyzes numerous acyl-transfer reactions. Are peptic acyl-enzyme intermediates involved in such reactions? To start, we examine the cleavage of Leu-Trp-Met-Arg at pH 3.4–4.5 in the presence of 25 mM tryptophanamide. Substantial amounts of Leu-TrpNH2 are generated. However, the appearance of this acyl-transfer product cannot be attributed to the intervention of Leu-pepsin and its trapping by tryptophanamide. Experiment proves that Leu-Trp-Met-Arg affords Leu3, which, in turn, reacts with tryptophanamide to produce Leu-TrpNH2. Both the formation of Leu3 from Leu-Trp-Met-Arg and the conversion of Leu3 + tryptophanamide into Leu-TrpNH2 can potentially implicate the generation and trapping of a Leu-pepsin intermediate. Does experiment support either possibility? The answer is no. Our data show that most of the Leu3 derived from Leu-Trp-Met-Arg stems from an autocatalytic condensation process whereby Leu3 already present speeds the conversion of the leucine residues of unreacted Leu-Trp-Met-Arg into more Leu3. Technical problems have prevented us from determining whether the first Leu3 formed results from the trapping of an acyl-enzyme intermediate. The generation of Leu-TrpNH2 from Leu3 was studied primarily via a more tractable analogous reaction: Leu-Trp-Leu + tryptophanamide Leu-TrpNH2. The mechanism governing these transformations is highly complex. Its major feature is an initial condensation between two molecules of substrate. All the examples investigated further illustrate the marked tendency of pepsin to catalyze condensation reactions between suitably constructed small peptides. The prevalence of these reactions complicates the interpretation of much data bearing on pepsin's mechanism of action.
Regulation of pyruvate dehydrogenase activity and glucose metabolism in post-ischaemic myocardium

Pyruvate dehydrogenase (PDH) is regulated both by covalent modification and through modulation of the active enzyme by metabolites. In the isolated heart, post-ischaemic inhibition of PDH, leading to uncoupling of glycolysis and glucose oxidation and a decrease in cardiac efficiency, has been described. In vivo, post-ischaemic reperfusion leads to metabolic abnormalities consistent with PDH inhibition, but the effects of ischaemia/reperfusion on PDH are not well characterized. We therefore investigated PDH regulation following transient ischaemia in vivo. In 33 open-chest dogs, the left anterior descending (LAD) was occluded for 20 min followed by 4 h reperfusion. In 17 dogs, dichloroacetate (DCA) was injected prior to reperfusion, while 16 dogs served as controls. In dogs without DCA, glucose oxidation and lactate uptake were lower in reperfused than in remote tissue, suggesting reduced flux through PDH. However, percent active and total PDH measured in myocardial biopsies were similar in both territories, excluding covalent enzyme modification or loss of functional enzyme. DCA activated PDH activity similarly in both regions and abolished differences in glucose oxidation and lactate uptake. Thus, decreased PDH flux in reperfused myocardium does not result from covalent modification or loss of total enzyme activity, but more likely from metabolite inhibition of the active enzyme. DCA leads to essentially complete activation of PDH, increases overall glucose utilization and abolishes post-ischaemic inhibition of glucose oxidation.
SU-E-T-23: TomoTherapy Patient QA Using Exit Detector Measurement of Pre-Treatment In-Air Delivery.

Purpose: Currently, the recommended TomoTherapy patient specific QA involves setting up a DQA procedure and delivering it to a phantom with an ion chamber and film measurement. The process is time‐consuming and the DQA result is susceptible to errors in phantom setup. Our study explores the feasibility of using TomoTherapy's intrinsic exit detectors to perform patient specific QA by measuring the fluence received by the detectors during pre‐treatment in‐air delivery for our STAT‐RAD workflow. Methods: A TomoTherapy patient plan is converted into a calibration procedure in which the couch remains out of the gantry. The signal measured by the exit detector is exported through manufactory provided software. In‐house developed software is used to reconstruct exit detector signal from the dicom‐exported delivery plan. The software relies on individual leaf profiles as well as tongue‐and‐groove profiles of each adjacent leaf‐pair extracted from an in‐house developed calibration procedure. The difference between the reconstructed and measured detector signal can be analyzed by a simple algorithm which has been developed to estimate the dose difference of any given point inside a patient or phantom. Several patient plans have been tested with this in‐air delivery QA method. In some of the tested plans, errors have been introduced to assure the estimated point dose error agrees with the ion chambermeasurement in a phantom. Results: The in‐house exit detector reconstruction software has been validated to be able to reconstruct the exit detector signal with errors <1%. The software estimated point dose agrees within 3% to the ion chambermeasurement.Conclusions: Our study shows that it is feasible and efficient to perform patient specific QA using the exit detector signal recorded during the in‐air pretreatment delivery. This approach is easy to perform and it is faster than conventional QA approach.
Reproducibility of an animal model simulating complex combat-related injury in a multiple-institution format.

Abstract : We developed a complex combat-relevant model of abdominal and extremity trauma, hemorrhagic shock, hypothermia, and acidosis. We then simulated injury, preoperative, and operative phases. We hypothesized that this model is reproducible and useful for randomized multicenter preclinical trials. Yorkshire swine were anesthetized, intubated, and instrumented. They then underwent femur fracture, 60% total blood volume hemorrhage, a 30-min shock period, induced hypothermia to 33 Degrees C, and hemorrhage volume replacement with 3:1 isotonic sodium chloride solution (NS) at each of three centers. Hemodynamic parameters were measured continuously. Thromboelastography, arterial blood gas, and laboratory values were collected at baseline, after the shock period, and after NS replacement. Thirty-seven animals were used for model development. Eight (21%) died before completion of the study period. Twenty-nine survivors were included in the analysis. MAP (+ or -SEM) after the shock period was 32 + or - 2 mmHg and was similar between centers ( P = 0.4). Mean pH, base deficit, and lactate levels were 7.29 + or - 0.02, 8.20 + or - 0.65 mmol/L, and 5.29 + or - 0.44 mmol/L, respectively, after NS replacement. These were similar between centers ( P greater than 0.05). Prothrombin time values increased significantly over time at all centers, reflecting a progressive coagulopathy ( P less than 0.02). Thromboelastography maximum amplitude values were similar among centers ( P greater than 0.05) and demonstrated progressively weakened platelet interaction over time ( P less than 0.03). Hematocrit was similar after controlled hemorrhage ( P = 0.15) and dilution ( P = 0.9). The pH, lactate, base deficit, and coagulation tests reflect a severely injured state. A complex porcine model of polytrauma and shock can be used for multi-institutional study with excellent reproducibility. A consistent severe injury profile was achieved, after which experimental interventions can be applied.
Imprint of First Stars Era in the Cosmic Infrared Background Fluctuations

We present the latest results on Cosmic Infrared Background (CIB) fluctuations from early epochs from deep Spitzer data. The results show the existence of significant CIB fluctuations at the IRAC wavelengths (3.6 to 8 μm) which remain after removing galaxies down to very faint levels. These fluctuations must arise from populations with a significant clustering component, but only low levels of the shot noise. There are no correlations between the source-subtracted IRAC maps and the corresponding fields observed with the HST ACS at optical wavelengths. Taken together, these data imply that 1) the sources producing the CIB fluctuations are individually faint with S ν −2 sr −1 at 3.6 and 4.5 μm and must have mass-to-light ratio significantly below the present-day populations, and 5) they have angular density of ~ a few per arcsec 2 and are in the confusion of the present day instruments, but can be individually observable with JWST .
The Impact of Geographic and Business Segment Diversification Upon Investor's Perceptions of Earnings of U.S.‐Based Multinational Enterprises

This study investigates how investors perceive the impact of U.S.‐based MNCs geographic and business segment diversification upon their earnings performance. Pooled cross‐sectional annual earnings response regressions for the years 1993 through 1997 are used for this investigation. Our results show that geographic segment diversification is valued by investors more than the business segment diversification especially in two cases: 1) when the business segmentation is low; and 2) when geographic segmentation is high. These results imply that business segment diversification is only valued when it takes place in international markets where it is relatively more difficult for individual investors to replicate industry diversified portfolio for themselves. Our research illuminates the contextual aspects of investors' perceptions of geographic and business segment diversification for multinational corporations by explicitly controlling for one dimension of corporate diversification while examining the earning‐returns impact of the other type of corporate diversification.
On the Dynamics of the Throughflow from the Pacific into the Indian Ocean

Abstract The circulation forced by an inflow of water through an eastern ocean boundary is investigated using two linear, viscid, and continuously stratified models. One of the models has a flat bottom, and solutions are obtained analytically; the other has a continental shelf, and solutions are found numerically. Without vertical mixing all the inflow continues across the ocean. With vertical mixing, however, part of it bends poleward to generate a coastal circulation. The presence of a shelf displaces the coastal currents offshore, but otherwise changes their structure and magnitude very little. Solutions suggest that the southward bending of the throughflow from the Pacific into the Indian Ocean may contribute to the Leeuwin Current off western Australia, but that it is not the dominant mechanism for driving the circulation there.
Enhancing organizational capacity to provide cancer control programs among Latino churches: design and baseline findings of the CRUZA Study.

Faith-based organizations (FBOs) have been successful in delivering health promotion programs for African Americans, though few studies have been conducted among Latinos. Even fewer have focused on organizational change, which is required to sustain community-based initiatives. We hypothesized that FBOs serving Latinos would be more likely to offer evidence-based strategies (EBS) for cancer control after receiving a capacity enhancement intervention to implement health programs, and designed the CRUZA trial to test this hypothesis. This paper describes the CRUZA design and baseline findings. We identified Catholic parishes in Massachusetts that provided Spanish-language mass (n = 65). A baseline survey assessed organizational characteristics relevant to adoption of health programs, including readiness for adoption, “fit” between innovation and organizational mission, implementation climate, and organizational culture. In the next study phase, parishes that completed the baseline assessment will be recruited to a randomized cluster trial, with the parish as the unit of analysis. Both groups will receive a Program Manual and Toolkit. Capacity Enhancement parishes will also be offered technical support, assistance forming health committees and building inter-institutional partnerships, and skills-based training. Of the 49 parishes surveyed at baseline (75%), one-third (33%) reported having provided at least one health program in the prior year. However, only two program offerings were cancer-specific. Nearly one-fifth (18%) had an active health ministry. There was a high level of organizational readiness to adopt cancer control programs, high congruence between parish missions and CRUZA objectives, moderately conducive implementation climates, and organizational cultures supportive of CRUZA programming. Having an existing health ministry was significantly associated with having offered health programs within the past year. Relationships between health program offerings and other organizational characteristics were not statistically significant. Findings suggest that many parishes do not offer cancer control programs, yet many may be ready to do so. However, the perceptions about existing organizational practices and policies may not be conducive to program initiation. A capacity enhancement intervention may hold promise as a means of increasing health programming. The efficacy of such an intervention will be tested in phase two of this study.
Optimization of Kinetic Proofreading: A General Method for Derivation of the Constraint Relations and an Exploration of a Specific Case

Abstract We have previously presented a general cost-accuracy relationship for a broad class of kinetic proofreading mechanisms. In this paper we present a general matrix method, based upon classical enzyme kinetics, for the derivation of the constraint relation that characterizes specific proofreading mechanisms. For purpose of illustration we present the method in the context of a conventional Michaelis-Menten mechanism with side reactions. We then explore optimization of the general cost function under a variety of different constraints that may exist for such a mechanism. In this way we are able to contrast different perspectives on the optimization of enzyme design.
Syntheses and Structures of Molybdenum Imido Alkylidene Pyrrolide and Indolide Complexes

An X-ray structural study of Mo(NAd)(CHCMe2Ph)(2,5-Me2NC4H2)2 (1; Ad = 1-adamantyl) reveals it to contain one η1-2,5-Me2NC4H2 ring and one η5-2,5-Me2NC4H2 ring. The structures of Mo(NAr)(CHCMe2Ph)(...
Hydrogenation of shallow and deep levels in silicon

Real-time electric field drift measurements, in situ capacitance-voltage profiling and deep level transient spectroscopy (DLTS) have been used to monitor hydrogen motion and hydrogen passivation of shallow and deep levels in silicon. Spontaneous hydrogen injection and very fast migration have been detected in the near-interface region of various Schottky barriers. The effective hydrogen diffusion is about 10−8 cm2 s−1 at 400 K, in agreement with the estimated value of 8 × 10−9 cm2 s−1 obtained by extrapolation from the high temperature diffusivity data. The effects of hydrogen motion on the DLTS spectra have been analyzed in 2 MeV electron-irradiated samples. The results of real-time in situ measurements clearly demonstrate that the fast-diffusing hydrogen is involved in the hydrogenation processes of both shallow and deep levels.
Repulsive potentials for the interaction of oxygen atoms with the noble gases and atmospheric molecules

Abstract Repulsive potentials between about 0.2 eV and 20 eV are determined for interactions of oxygen atoms with the noble gas atoms and with H 2 , N 2 , O 2 , NO, CO, CO 2 and H 2 O molecules from incomplete total scattering cross sections. Good agreement with theory is obtained for the noble gases. The potentials for the interaction with molecules obtained by assuming spherically symmetric potentials are compared with the same potentials computed by averaging the cross sections for different orientations of the molecules. By introducing reduced variables, the problem of finding two isotropic potential parameters is simplified to a search for one, the other being determined by a least-squares constraint.
THE STRESSES AROUND A HOLE IN A LINEAR ELASTIC MATERIAL WITH VOIDS

Etude des contraintes planes et des deformations planes quasi statiques pour un materiau elastique lineaire avec des vides. Application au probleme d'un cylindre circulaire creux