cssi/SciSciGPT-SciSciNet huggingface dataset:
An Asymptotic, Thermo-Diffusive Ignition Theory of Porous Solid Fuels

The governing equations of thermal ignition are analyzed for porous solid fuel, such as coal, of various two-dimensional and axisymmetric geometries by the Laplace asymptotic method. Mass diffusion of the gaseous oxidant through the porous fuel is included. The nonlinear partial differential equations of energy and mass balances in time-space coordinates containing the Arrhenius volumic chemical reaction terms are analyzed. By employing the Laplace asymptotic technique and by invoking a certain limit theorem, the governing equations are reduced to a first order ordinary differential equation governing the fuel surface temperature, which is readily solved numerically. Detailed discussion of the effects of the various governing parameters on ignition is presented. Because of the basically closed-form nature of the solutions obtained, many general and fundamental aspects of the ignition criteria hitherto unknown are found. (auth)
Structures of the paraelectric and ferroelectric phases of NaD3(SeO3)2 by neutron diffraction

Abstract The crystal and molecular structure of the paraelectric and the ferroelectric phase of NaD3(SeO3)3 has been determined and refined using neutron diffraction data. Above Tc = 270°K the paraelectric phase is monoclinic, belonging to space group P21/n with Z=2, a=10.365(2), b=4.850(1), c=5.792(1) and β=91.16(3) at 298°K. The paraelectric phase is characterized by deuterium atoms in positions of two-fold disorder. The ferroelectric phase below Tc belongs to space group Pn with Z=4, a=10.314(3), b=9.663(2), c=5.768(2) and β=91.23(3) at 173°K. To collect proper neutron diffraction data on the ferroelectric phase, it was necessary to prevent small domain formation by poling the crystal in an external field of 15 Kv/cm during cooling-warming cycles through Tc. The deuterium atoms are ordered in the ferroelectric phase and the present determination of the particular way in which they are ordered resolves a disagreement between two previous resonance1,2 studies. Our results are in agreement with the model ...
Fast prediction of scattering in mountainous terrain using commonly visible surfaces

This paper discusses a computer program for deterministic prediction of radio wave scattering in hilly and mountainous terrain using a DTED terrain database. A fast and accurate visibility algorithm with a linear computational complexity and little RAM requirement is invented to find the terrain elements that are commonly visible to both ends of the communication links. Comparing with the vertical plane contribution predicted by the TIREM model, we find that in about 1/3 of the cases the terrain scattering contribution is more significant than the vertical plane contribution in a typical mountainous terrain. We also find milliseconds computation times per link can be achieved on a personal computer for large maps by pre-computing macro-visibility. Computation that finds visibility on-the-fly takes 6 times longer.
A phonologically based analysis of misspellings by third graders with disordered-phonology histories

Misspellings evidenced in written responses of third graders during administration of a battery containing 25 true words and 20 nonsense syllable items were analyzed phonologically. Children with histories of disordered phonologies evidenced more phonologically based deviations in their written misspellings than did their peers who had experienced normal phonological development. In addition, the children with disordered-phonology histories relied more on less productive spelling strategies and evidenced poorer phonological awareness skills than their peers with normal-phonology histories.
Quality Control In Diagnostic Radiology

The factors that I consider to be absolute essentials in our quality control program at Mayo Clinic are x-ray generator calibration, sensitometric regulation of film processing, x-ray exposure technique system, and on-line quality control. Other aspects of a complete system such as measurement of x-ray tube focal spot size, radiation output checks, checks on the performance of our image systems, and evaluation of new products are desirable to improve our work; these have been incorporated as they have become available. An effective quality control program can minimize patient exposure, can improve and maintain the overall diagnostic quality of the radiographs accepted for interpretation, and can save money in the institution.© (1976) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Intestinal calcium transport: Evidence for two distinct mechanisms of action of 1,25-dihydroxyvitamin D3

Abstract The response of the small intestine in the vitamin D-deficient rat to a single intrajugular injection of 1,25-dihydroxyvitamin D 3 has been studied. The time course of 1,25-dihydroxyvitamin D 3 -induced transport suggests that two separate responses occur. The first or initial response reaches a maximum at 6 h after 1,25-dihydroxy vitamin D 3 administration, decays, and is effectively gone by 12 h postinjection. This response does not appear to be associated with alkaline phosphatase activity. The second or late response first appears roughly 12 h after dosing, reaches a maximum at 24 h, and remains elevated for up to 72 h. This response is accompanied by an elevation of alkaline phosphatase activity and appears to be mediated through the action of 1,25-dihydroxyvitamin D 3 on the absorptive cell during its normal differentiation and migration up the villus.
Causes of death in racehorses over a 2 year period.

Summary Necropsies were performed on 496 horses that had a fatal injury or illness at a California racetrack during the period February 20th 1990 to March 1st 1992. The primary cause of death was categorised by breed, activity at time of injury or illness and organ system affected. Most of the submissions were Thoroughbred horses (432) and Quarter Horses (46). Most of the injuries occurred while racing (42%) and in training sessions (39%); with fewer non-exercise (12%) and accident (7%) related injuries or illnesses. Musculoskeletal injuries accounted for 83% of the Thoroughbred and 80% of the Quarter Horse submissions. The Thoroughbred horses incurred 306 fractures with 263 in the limbs and 90% of those in the forelimbs. The proximal sesamoid bone(s), third metacarpal bone and humerus were the most common bones fractured in Thoroughbred horses and Quarter Horses. Other major causes of death included respiratory, digestive and multi-organ system disorders.
Electron transfer and spin-flip processes in atom-atom collisions from variationally improved time-dependent Hartree-Fock results.

A variational functional for transition amplitudes is applied to atom-atom collisions using a time-dependent formalism. The transition amplitude is a functional of two independent trial wave functions with specified initial and final conditions, respectively. Transition probabilities are obtained by evaluating the functional in terms of standard time-dependent Hartree-Fock (TDHF) trial functions. The TDHF method is implemented by expanding the molecular orbitals as linear combinations of traveling atomic orbitals. The procedure requires no other molecular integrals than those needed to construct the Fock operator. The present method is applied to He+${\mathrm{He}}^{2+}$ and ${\mathrm{H}}^{+}$+${\mathrm{He}}^{+}$ collisions with specified nuclear trajectories using a minimal atomic-orbital basis set. Within this model an exact, close-coupling-type solution is also feasible, and has been obtained for comparison purposes. Numerical values of probabilities and of cross sections obtained from the variational functionals for elastic, spin-flip, and one- and two-electron transfer processes show substantial improvements over the standard TDHF results.
A new solution for Thue's problem

Abstract An infinite square-free sequence of elements of {0, 1, 2} is constructed by using an auxiliary binary sequence in a way different from Thue and Morse's method. Furthermore, the infinite sequence is proved not to be generated by any morphism on the free monoid {0, 1, 2}∗.
Parental alcohol use, problem drinking, and children's injuries.

Objective. —Millions of US children are exposed to parents who are problem drinkers, yet there is little evidence about the effect of parental alcohol consumption on children's health. The aim of this study was to assess the association between children's injuries and parental drinking. Design. —Survey of a nationally representative sample of the US population by household interview. Participants. —112 360 children and parents from single-family households, with data from the Alcohol and Child Health supplements to the 1988 National Health Interview Survey. Main Outcome Measure. —Serious injuries—injuries resulting in hospitalization, surgical treatment, missed school, one half day or more in bed. Results. —Children of mothers categorized as problem drinkers had 2.1 times the risk of serious injury as children of mothers who were nondrinkers (95% CI, 1.3 to 3.5). Other measures of mothers' alcohol consumption (ie, average, maximum, and self-rated consumption) were unrelated to child injuries, as were all measures of fathers' drinking. Children of women who were problem drinkers married to men rated as moderate or heavy drinkers had a relative risk of serious injury of 2.7 (95% CI, 0.8 to 8.6) compared with children of nondrinkers. Conclusion. —Children of women who are problem drinkers have an elevated injury risk; children with two parents who are problem drinkers are at higher risk. Further research is needed on potential mechanisms and interventions. Primary prevention might be enhanced if physicians elicited information about parental drinking, helped secure appropriate treatment, and participated in public health efforts to reduce the deleterious effects of alcohol. (JAMA. 1992;267:3166-3171)
Stationary states and energy cascades in inelastic gases.

We find a general class of nontrivial stationary states in inelastic gases where, due to dissipation, energy is transferred from large velocity scales to small velocity scales. These steady states exist for arbitrary collision rules and arbitrary dimension. Their signature is a stationary velocity distribution $f(v)$ with an algebraic high-energy tail, $f(v)\ensuremath{\sim}{v}^{\ensuremath{-}\ensuremath{\sigma}}$. The exponent $\ensuremath{\sigma}$ is obtained analytically and it varies continuously with the spatial dimension, the homogeneity index characterizing the collision rate, and the restitution coefficient. We observe these stationary states in numerical simulations in which energy is injected into the system by infrequently boosting particles to high velocities. We propose that these states may be realized experimentally in driven granular systems.
The MMT bag for emission source sampling: design and evaluation.

ABSTRACT This paper presents the design and evaluation results for a metal-coated multilayer Tedlar (MMT) bag that was developed for the collection of source emissions. The applicability of the MMT bag was evaluated for a number of important greenhouse relevant gases: CO, CO2, CH4, N2O, and total hydrocarbons (THCs). The bag was tested for durability and stability for a range of concentrations of the tested compounds using both laboratory-prepared samples and real source samples. The results show that all tested compounds were more stable when stored in the MMT bag than when stored in a regular Tedlar bag. These compounds can be stored at room temperature for at least 3 months without significant changes in concentration. When properly packed, the MMT bag is durable and may be shipped by air. The MMT bag is lower in cost, lighter in weight, and easier to clean, and it requires less devices during the subsequent laboratory analysis compared with a stainless steel canister, which is often used to collect ai...
Fatal Scopulariopsis brevicaulis infection in a paediatric stem-cell transplant patient treated with voriconazole and caspofungin and a review of Scopulariopsis infections in immunocompromised patients.

Scopulariopsis brevicaulis is an airborne mould that causes 1-10% of cases of onychomycosis, 1,2 cutaneous lesions, 3 or severe soft tissue infection following traumatic or surgical injury in immunocompetent patients. 4,5 In this case we describe another dramatic presentation of Scopulariopsis species infection, widely disseminated infection, in a child after stem-cell transplantation with graft versus-host-disease who failed lipid amphotericin B therapy as well as voriconazole plus caspofungin combination therapy. We also review 12 cases of Scopulariopsis species infection in immunocompromised patients.
Abstract 3892: Anti-cooperative allosteric inhibitors of thymidylate synthase as novel antineoplastic agents

Thymidylate synthase (TS) inhibitors are a class of antineoplastic agents widely used for the treatment of gastrointestinal, breast, ovarian and other cancers. TS catalyzes reductive methylation of dUMP to dTMP and serves as the sole de novo source of thymidylate inside the cell. While TS is essential for DNA biosynthesis and normal cell proliferation, TS overexpression has been associated with resistant tumor phenotype and poor prognosis. Although TS inhibitor 5-flourouracil (5-FU) continues to be one of the most frequently used chemo-therapeutic agents, 5-FU and its metabolites can cause significant liver, cardiac and bone marrow toxicity and are associated with development of drug resistance. In this study, we developed a new strategy that targets TS subunit cooperativity by freezing isoform interconversions and structural dynamics of the enzyme. In TS catalytic mechanism, conserted motion of amino acid residues 181-197 brings the catalytic Cys195 in and out of the active site. These small scale motions that translate across the dimer interface upon substrate binding and product release are integral to TS enzymatic function and can be taken advantage of in structure-based design of its inhibitors. For this purpose, we selected TS crystal structure with high asymmetry between the subunits (PDBID:1HVY) and used it as a template for molecular docking. The structure was prepared by removing heteroatoms and liganded molecules, followed by energy minimization in UCSF Chimera (1.5.2) and testing resulting geometries in Coot (0.6.2). We identified 5 potential docking sites and selected the site at the dimer interface specific to inactive conformation of TS. National Cancer Institute (NCI) small molecule library of 139,735 compounds was extracted from ZINC and pruned for redundant structures and molecules with molecular weight less than 200 Da. Resulting compound library was docked (DOCK6.4) into the selected site in 1000 orientations with flexible bond parameters enabled. The top 1000 hits were re-scored using AMBER and visualized in PyMOL to check for consistency and geometric fit. 837 out of 1000 molecules were further selected and re-ranked based on predicted physicochemical characteristics (cLogP, pKa, solubility, etc.). The twenty-seven highest ranked compounds were requested from the NCI and tested for their effects on viability in HeLa, K562 and A549 human cancer cell lines. Five out of 27 compounds reduced viability by more than 50% at a concentration of 10uM; one of the compounds was effective below 1uM. In conclusion, by using this new approach that targets TS subunit cooperativity, we identified small molecules with potential anti-cancer activity. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3892. doi:1538-7445.AM2012-3892
Noladin ether acts on trabecular meshwork cannabinoid (CB1) receptors to enhance aqueous humor outflow facility.

PURPOSE. To study the effects of 2-arachidonyl glyceryl ether (noladin ether), an endocannabinoid ligand selective for cannabinoid (CB)1 receptor, on aqueous humor outflow facility, to investigate the involvement of trabecular meshwork CB1 receptors and the p42/44 MAP kinase signaling pathway and to explore the cellular mechanisms of noladin ether-induced changes of outflow facility. METHODS. The effects of noladin ether on aqueous humor outflow facility were measured in a porcine anterior-segment-perfused organ culture model. The expression of CB1 receptors on cultured porcine trabecular meshwork cells and the coupling of these receptors to p42/44 MAP kinase was determined by immunofluorescence microscopy and Western blot analysis. Both Western blot and zymography were used to monitor the effects of noladin ether on matrix metalloproteinase (MMP)-2. In morphologic studies, AlexaFluor 488-labeled phalloidin staining was used to examine actin filament, and immunohistochemistry with anti-paxillin antibodies was used to detect focal adhesions. RESULTS. Within 1 hour after adding 3, 30, or 300 nM of noladin ether, the aqueous humor outflow facility increased concentration dependently. The effect of 30 nM of noladin ether was completely blocked by SR141716A, a selective CB1 antagonist. Positive signals were detected on cultured porcine trabecular meshwork cells with an anti-CB1 antibody in immunofluorescence microscopy and Western blot studies. Treatment of trabecular meshwork cells with 30 nM of noladin ether activated p42/44 MAP kinase, whereas pretreatment with SR141716A blocked the p42/44 MAP kinase-activating effects of noladin ether. In addition, the enhancement of outflow facility induced by noladin ether was blocked by pretreatment of porcine anterior segments with PD98059, an inhibitor of p42/44 MAP kinase pathway. Furthermore, noladin ether treatment caused rounding of trabecular meshwork cells, and there was a decrease of actin stress fibers, as well as a decrease in focal adhesions. These noladin ether-induced morphologic changes were also blocked by SR141716A and PD98059. CONCLUSIONS. The results demonstrate for the first time that administration of noladin ether, an endocannabinoid agonist selective for the CB1 receptor, increases aqueous humor outflow facility. The data also show that noladin ether-induced enhancement of outflow facility is mediated through the trabecular meshwork CB1 receptor, with an involvement of p42/44 MAP kinase signaling pathway and changes in actin cytoskeletons.
A Field Tests of Interspecific Competition on Oviposition of Gall-Forming Sawflies on Willow

We performed a manipulative field experiment to test for competitive effects of the stem galling sawfly (Euura lasiolepis) on three other gall—forming sawflies on arroyo willow (Salix lasiolepis). Within a willow clone, three branches were left untreated, three branches had E. lasiolepis females placed on them in nylon screen bags during that species' oviposition period, and three branches were bagged during that same period but had no sawflies introduced. When oviposition by E. lasiolepis was completed, bags were removed, and three other sawflies were permitted to oviposit on the branches. We found no significant interspecific competitive effects on the densities of three species in response to 9— and 17—fold increase in densities of galls of the stem—galling sawfly on branches of field plants in 1985 and 1986, respectively. The densities of stem gallers on the experimental branches were high, but were near densities observed on some unmanipulated field plants. The density of the petiole galler in 1985 was higher on branches with the stem galler than was the density of the leaf galler. This suggested a facilitation effect, which was not repeated in 1986. The leaf folder had significantly greater densities than the leaf galler or petiole galler. However, bagging of branches resulted in greatly reduced densities of the leaf folder compared to unbagged control branches in both years. The petiole galler and leaf galler were not affected by bagging in either year, probably due to their later oviposition phenology. Within treatment branches, where stem gall densities were high, these three sawfly species did not significantly avoid oviposition on shoots with stem galls, and in 1986 there were generally positive co—occurrence patterns of each of these species with stem galls on shoots. We conclude that interspecific competitive effects on gall density was not important under these field conditions for the leaf galler and the petiole galler, but bagging effects on the leaf folder density could have reduced the likelihood of detecting competitive effects by the stem galler on this species. Differences in the results of this study with an earlier experiment may be related to compensatory ability of the larger field plants and differences in stem gall densities.
Analysis of the Structural Determinants Underlying Discrimination between Substrate and Solvent in β-Phosphoglucomutase Catalysis†‡

The β-phosphoglucomutase (β-PGM) of the haloacid dehalogenase enzyme superfamily (HADSF) catalyzes the conversion of β-glucose 1-phosphate (βG1P) to glucose 6-phosphate (G6P) using Asp8 of the core domain active-site to mediate phosphoryl transfer from β-glucose 1,6-(bis)phosphate (βG1,6bisP) to βG1P. Herein we explore the mechanism by which hydrolysis of the β-PGM phospho-Asp8 is avoided during the time that the active site must remain open to solvent in order to allow the exchange of the bound product G6P with the substrate βG1P. Based on structural information, a model of catalysis is proposed in which the general acid/base (Asp10) side chain moves from a position where it forms a hydrogen bond to the Thr16-Ala17 of the domain-domain linker, to a functional position where it forms a hydrogen bond to the substrate leaving-group O and a His20-Lys76 pair of the cap domain. This repositioning of the general acid/base within the core domain active site is coordinated with substrate-induced closure of the cap domain over the core domain. The model predicts that Asp10 is required for general acid/base catalysis and for stabilization of the enzyme in the cap-closed conformation. It also predicts that hinge residue Thr16 plays a key role in productive domain-domain association, that hydrogen bond interaction with the Thr16 backbone amide NH is required to prevent phospho-Asp8 hydrolysis in the cap-open conformation, and that the His20-Lys76 pair plays an important role in substrate-induced cap closure. The model is examined via kinetic analyses of Asp10, Thr16, His20, and Lys76 site-directed mutants. Replacement of the Asp10 by Ala, Ser, Cys, Asn, or Glu resulted in no observable activity. The kinetic consequences of the replacement of linker residue Thr16 with Pro include a reduced rate of Asp8 phosphorylation by βG1,6bisP, a reduced rate of cycling of the phosphorylated enzyme to convert βG1P to G6P, and an enhanced rate of phosphoryl transfer from phospho-Asp8 to water. The X-ray structure of the T16P mutant at 2.7 A resolution provides a snapshot of the enzyme in an unnatural cap-open conformation where the Asp10 side chain is located in the core-domain active site. The His20 and Lys76 site-directed mutants show reduced activity in catalysis of the Asp8-mediated phosphoryl transfer between βG1,6bisP and βG1P but no reduction in the rate of phospho-Asp8 hydrolysis. Taken together, the results support a substrate induced-fit model of catalysis in which βG1P binding to the core domain facilitates recruitment of the general-acid/base Asp10 to the catalytic site and induces cap closure.
Country-of-origin determinants of foreign direct investment in an emerging market: the case of Mexico

Abstract Foreign direct investment (FDI) research has generally focused on inward FDI to large, developed nations. Very limited research has examined the country-of-origin factors that are related to FDI into the developing nations (emerging markets) that are becoming increasingly important in the global economy. In this paper, we provide the first empirical test of a multidimensional, country-of-origin model of factors related to FDI in an emerging market — Mexico. Economic, socio-political, and geographic factors are hypothesized to be important country-of-origin determinants of FDI into Mexico. The results indicate that some factors, such as the level of bilateral trade, home-country GDP, political risk, geographic distance, and exchange rates, are related to FDI into Mexico. At the same time, relationships between FDI and country-of-origin factors, such as market size (GDP) and cultural distance, that have previously held in research on FDI to large, developed nations do not hold in the same way in the emerging market context. Separate consideration of efficiency-seeking (maquila) FDI indicates that bilateral trade, wage rate, GDP, and the exchange rate contribute significantly to the explanation of inward FDI in Mexico.
Theoretical model for high-power diamond laser optics using high-velocity liquid-metal jet impingement cooling

In 1988 I presented a paper, `Fly's Eye Modular Optic,' in the Los Angeles Symposium that described an optic for high power laser systems that provided for a modular system of hexagonal components that were independently cooled using a high velocity jet pointed normal to the back surface of the optical faceplate. In this paper we look at the use of diamond optical materials in concert with high velocity jet impingement heat transfer of various liquid metal mediums. By using this combination of techniques and materials we can push the laser damage threshold of optical components to even higher levels of absorbed flux density. The thrust of this paper is to develop a theoretical model for use on optical elements subject to very high continuous flux density lasers and to evaluate the use of commercial diamond substrates with conventional optical thin films and conventional substrates with CVD diamond films. In order to assume the very high absorbed flux densities, it is necessary to have a heat transfer technique capable of maintaining the optical component at a stable temperature and below the damage threshold of the optical materials. For the more common materials, thermal shock and subsequent failure in bi-axial shear have proven to be one of the major constituents of the optical damage. In this paper we look at the thermal shock, vis-a-vis, the melting point of some of the materials.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Recruitment Practices and the Politics of Inclusion in Cancer Clinical Trials

Since the U.S. National Institutes of Health (NIH) Revitalization Act of 1993, researchers with federal funding have been required to include “minorities and women” in their clinical trials, and inclusion in research has come to be seen as an important strategy for reducing health disparities. On the basis of ethnographic research in oncology clinics in an academic medical center and a public hospital over a period of two years, this article examines how the NIH inclusion mandate is playing out in the context of oncology clinical trials. We argue that although individual patients are recruited to particular trials by individual providers, recruitment processes are shaped by the structural inequities in the U.S. health care system that create differential access to medical facilities with different and unequal research infrastructures. Given the heterogeneity of clinical trials, research infrastructures, and the U.S. health care system, the meanings of inclusion in research are multiple, and inclusion by itself does not ensure equity.
UNLV Libraries and the digital identification frontier

Purpose – To reflect on activities and developments related to the 3M™ Digital Materials Flow Management since its implementation at the UNLV Libraries, including system hardware and software developments and the UNLV Libraries' evolving relationship with 3M™.Design/methodology/approach – Following an introduction which highlights the major 3M™ Digital Materials Flow Management components in place at the UNLV Libraries, product improvements that have expanded the functionality of the system are detailed, patrons and staff benefits of the technology are described, and RFID privacy issues at the UNLV Libraries are examined.Findings – Expanded capability and use of the 3M™ Digital Materials Flow Management system has allowed the UNLV Libraries to establish more efficient processes for undertaking collection management activities, such as inventory and weeding. The system has also had a positive impact on customer service. Benefits of the system currently outweigh the potential risks in terms of patron privac...
Peroxiredoxin stabilization of DE-cadherin promotes primordial germ cell adhesion.

Summary Regulated adhesion between cells and their environment is critical for normal cell migration. We have identified mutations in a gene encoding the Drosophila hydrogen peroxide (H 2 O 2 )-degrading enzyme Jafrac1, which lead to germ cell adhesion defects. During gastrulation, primordial germ cells (PGCs) associate tightly with the invaginating midgut primordium as it enters the embryo; however, in embryos from jafrac1 mutant mothers this association is disrupted, leaving some PGCs trailing on the outside of the embryo. We observed similar phenotypes in embryos from DE-cadherin/ shotgun ( shg ) mutant mothers and were able to rescue the jafrac1 phenotype by increasing DE-cadherin levels. This and our biochemical evidence strongly suggest that Jafrac1-mediated reduction of H 2 O 2 is required to maintain DE-cadherin protein levels in the early embryo. Our results present in vivo evidence of a peroxiredoxin regulating DE-cadherin-mediated adhesion.
Investigating CXCR4 expression in canine appendicular osteosarcoma.

Background: The tropomyosin-related kinase A (TrkA) proto-oncogene encodes for a receptor that binds with high affinity to the neurotrophin ligand, nerve growth factor (NGF). Intracellular signaling mediated by the TrkA/NGF axis orchestrates neuronal cell differentiation, mitogenesis, and survival. Interestingly, TrkA also is expressed by bone forming cells, and its signaling promotes antiapoptotic effects in actively dividing osteoblasts. Hypothesis: In canine immortalized cell lines and naturally occurring tumor samples, osteosarcoma (OSA) cells will express TrkA. In canine OSA cell lines, TrkA signaling will promote cell mitogenesis and survival. Methods: In vitro, TrkA expression in canine OSA cell lines was assessed by reverse transcriptase-polymerase chain reaction, flow cytometry, and immunocytochemistry. In vitro, the involvement of TrkA-mediated signaling for cell mitogenesis and survival were investigated with commercially available assays. In vivo, TrkA expression was evaluated in primary tumors and pulmonary metastases with immunocytochemistry and immunohistochemistry, respectively. Results: In vitro, canine OSA cells expressed TrkA mRNA and protein. Ligation of TrkA with exogenous NGF did not induce mitogenesis. Blockade of TrkA signaling with either a protein kinase inhibitor or NGF-neutralizing antibody induced apoptosis of canine OSA cell lines. In vivo, the majority (10/15) of canine OSA primary tumors and pulmonary metastases (9/12) expressed TrkA protein. Conclusions and Clinical Importance: Canine OSA cells express TrkA, and its signaling protects against apoptosis. Most dogs with spontaneously arising OSA express TrkA within their primary tumors and pulmonary metastatic lesions, warranting further investigations with TrkA antagonists as a novel treatment option for canine OSA.
Memantine ameliorates scopolamine-induced amnesia in chicks trained on taste-avoidance learning

In day-old chicks trained on the one-trial taste-avoidance task, activation of NMDA receptors by glutamate is particularly important in the initial stages of memory consolidation. In addition, acetylcholine receptor activation has been shown to be a necessary component of memory formation for this task because injection of scopolamine produces amnesia. Memantine, a non-competitive NMDA receptor antagonist, improves memory formation under certain impairing circumstances, despite inhibiting the activation of NMDA receptors. The present experiments tested the hypothesis that memantine can ameliorate scopolamine-induced amnesia in day-old chicks (Gallus gallus domesticus) trained on the one-trial taste-avoidance task. Three experiments assessed the effects of scopolamine, memantine, and glutamate in this task. The results of Experiment 1 demonstrated that 50.0mM scopolamine produces significant amnesia. In Experiment 2, 1.0mM memantine reversed the scopolamine-induced amnesia, while other doses were ineffective. In Experiment 3, injection of 50.0mM glutamate in combination with scopolamine reversed the memantine amelioration. These results indicate a relationship between glutamate and acetylcholine in memory formation in the day-old chick.
Sympathoexcitation from the rostral ventrolateral medulla is mediated by spinal NMDA receptors

These studies examined the role of spinal N-methyl-D-aspartic acid (NMDA) receptors in mediating sympathoexcitation evoked by stimulation of neurons in the rostral ventrolateral medulla (RVLM). In urethane-anesthetized rats, blood pressure, heart rate, and splanchnic sympathetic nerve activity (SNA) were recorded. The NMDA receptor antagonist D-2-amino-7-phosphonoheptanoic acid (D-AP7) was administered to the spinal cord via intrathecal (IT) catheter. Blockade of spinal NMDA receptors reduced arterial blood pressure, heart rate, and SNA. Spinal administration of D-AP7 markedly attenuated the pressor and sympathoexcitatory responses evoked by L-glutamate stimulation of the RVLM. The small increases in heart rate evoked by stimulation of the RVLM were not affected by IT administration of D-AP7. These results indicate that NMDA receptors in the spinal cord mediate the pressor and sympathoexcitatory responses evoked by activation of a bulbospinal pathway originating from the RVLM. Moreover, these data suggest that excitatory amino acid neurotransmitters and NMDA receptors in the spinal cord play an important role in the maintenance and regulation of SNA and cardiovascular function.
Nitric oxide and differential effects of ATP on mitochondrial permeability transition.

The mitochondrial permeability transition pore (PTP) undergoes a calcium-dependent transition (MPT) that disrupts membrane potential and releases apoptogenic proteins. Because PTP opening is enhanced by oxidation of thiols at the so-called "S-site," we hypothesized that nitrogen monoxide (NO*) could enhance the open probability of the PTP, e.g., by S-nitrosylation or S-thiolation. At low NO donor concentrations (1 to 20 microM), PTP opening in succinate-energized liver mitochondria at nonlimiting calcium was delayed or unaffected, while it was accelerated by NO donors at 20 to 100 microM. At low donor concentrations, PTP opening was facilitated twofold by adenosine triphosphate (ATP), which normally delays PTP opening. Among NO donors, the oxatriazole GEA 3162, with an activation constant (Ka) of 1.9 microM at 500 microM ATP was more effective at enhancing pore transition than SIN-1 or SNAP. NO donor effects were superseded by diamide, which induces disulfide formation, but independent of SH-adduct formation by alkylation. NO-related changes in PTP function were accompanied by protein mixed disulfide formation, inhibited by dithiothreitol (DTT), and reversed by DTT after donor addition. PTP opening was stimulated in the presence of ATP by L-arginine-dependent NO production, i.e., mitochondrial NOS activity. ATP-facilitated pore opening was sensitive to atractyloside and depended on nucleotide interactions but not on hydrolysis, because specific nonhydrolyzable ATP analogs accelerated pore opening. These data indicate NO can influence pore transition by oxidation of thiols that produce conformational changes governing the ATP interaction at the adenine nucleotide transporter.
Annealing and Glass Transition of Starch

The enthalpy of the order-disorder transition of starch increased as the starch hydration period was increased from 1 h to 24 h. This was explained as the exothermic heat of hydration cancelling part of the endothermic heat of melting. Annealing of starch was shown to occur at 3 to 8°K below the Tm of starch. This would suggest that the Tg and Tm of starch does not occur at the same temperature. Ausgluhen und Glasubergang von Starke. Wenn die Starke-Hydratationsperiode von 1 h auf 24 h verlangert wurde, nahm die Enthalpie der Ordnungs-Unordnungs-Umwandlung zu. Dies wurde mit der exothermen Hydratationswarme erklart, die einen Teil der endothermen Schmelzwarme aufhob. Es wurde gezeigt, das das Ausgluhen von Starke bei 3 bis 8°K unter dem Tm (Schmelzpunkt) der Starke eintritt. Dies wurde bedeuten, das die Tg (Glasubergangs-Temperatur) und der Tm der Starke nicht bei der gleichen Temperatur liegen.
Localization of the lateral geniculate nucleus monophasic waves associated with paradoxical sleep in the cat

Abstract A movable electrode system has been used to study the characteristics and localization of the monophasic waves which appear in the cat lateral geniculate nucleus during paradoxical sleep. The results include the following: 1. 1. Monophasic waves were of greatest amplitude during the first 40 sec of paradoxical sleep and then diminished to about 70% of this initial value. 2. 2. Negative monophasic waves were localized to the lateral geniculate nucleus and similar positive waves were localized to the adjacent terminal part of the optic tract. 3. 3. Monophasic waves occurred as essentially simultaneous events throughout the region studied. 4. 4. The wave localization studies indicate that the potential field associated with monophasic waves is a dipole having its negative pole within the lateral geniculate nucleus and its positive pole in the terminal optic tract. Such a field might be generated by (a) depolarization of incoming optic tract fibers as they terminate in the nucleus or by (b) depolarization (or the removal of tonic hyperpolarization) of the cell bodies or dendritic processes of lateral geniculate neurons which send their axons on a centrifugal course into the optic tract. 5. 5. The localization and wave form of lateral geniculate monophasic waves differed significantly from that of evoked responses to light.
Partial purification and characterization of porcine platelet-derived growth factor (PDGF)☆

Platelet derived growth factor (PDGF) has been partially purified from porcine platelets. Purification steps included heparin-agarose chromatography of the material released by thrombin-stimulated washed porcine platelets and Blue-Sepharose chromatography. Preparative isoelectric focusing showed that isoelectric point of porcine PDGF is at pH 10.0-11.0 and elution experiments from sodium dodecyl sulfate (SDS) polyacrylamide gels indicated that its molecular weight is close to 30 kD. The immunoglobulin fraction prepared from anti-human PDGF serum inhibited the mitogenic activity of porcine PDGF. These experiments suggest a homology of porcine and human PDGF. Porcine platelet factor 4 and porcine platelet basic protein were devoid of significant mitogenic activity.
Observation on the lateral olfactory tract of the rat

The number and size of the axons in the later olfactory tract of the rat have been measured at several rostro-caudal levels, from material prepared for electron microscopy. Immediately caudal to the olfactory peduncle, an average of 42,000 +/- 3,000 axons were counted in the tract, while near the caudal limit of the tract an average of 32,000 +/- 2,800 axons were counted. The average internal cross-sectional area of axons measured at two levels of the tract was 1.6 +/- 1.3 mum2 and 1.1 +/- 0,9 mum2, corresponding to average internal diameters 1.4 +/- 1.3 mum and 1.2 +/- 1.1 mum, respectively. The axons in the lateral part of the tract were found to be significantly larger than those in the medial part of the tract; for one level the average cross-sectional area of axons in the lateral part of the tract was 1.6 +/- 1.0 mum2 (equivalent diameter 1.4 +/- 1,1 mum) while only 0.7 +/- 0.6 mum2 (equivalent diameter 0.9 +/- 0.9 mum) in the medial part of the tract. The thickness of the myelin sheath of the axons is generally related to axon diameter, increasing from 0.1-0.2 mum for axons 0.4 to 0.8 mum in diameter to 0.3-0.4 mum for axons greater than 2.0 mum in diameter. The ratio of the inside diameter to the outside diameter of the fiber (ratio "g") is between 0.7 and 0.8 for most axons in the lateral olfactory tract. The axons which leave the tract laterally and medially are substantially smaller than the axons within the tract (average cross-sectional area 0.55 +/- 0.35 mum2 on the lateral side) and probably are collaterals of the axons within the tract. Unmyelinated nerve processes, probably axons, were also found in the tract. Qualitative observations from light and electron microscopical material agree well with the quantitative data, and further suggest that mixing of axons from different parts of the olfactory bulb occurs in the rostral part of the tract. This is supported by experiments with injections of 3H-amino acids into localized portions of the olfactory bulb. These indicate that there is some degree of point-to-point organization in the most rostral part of the tract, but that this is lost in the caudal part of the olfactory peduncle.
Hindered sintering behaviors of titania nanoparticle-based materials

Absatract Porous material sintering is gaining more attraction because of the need for catalyst supports, sensors, solar cells, or other desired interactions with the enviroment. In this study, anatase TiO 2 nanoparticle suspensions are cast and sintered into porous materials. Surprisingly, suspension preparation condition has a drastic effect on sintered grain size, relative density, and shrinkage. When the suspension is prepared at basic condition with polyacrylic acid (PAA) as the dispersant, the sample shows faster shrinkage with much larger grain sizes. When the suspension is prepared at acidic condition with polyethylene glycol (PEG) as the dispersant, the sample has much slower shrinkage with minimal grain growth. The fundamental cause is the special organic residuals adsorbed on particle surfaces. This provides a simple yet extremely effective approach to produce nano grain-sized and highly porous materials.
Determination of mean particle size using the electrical aerosol detector and the condensation particle counter : Comparison with the scanning mobility particle sizer

Abstract Two methods for determining mean particle size of an ultrafine particle size distribution were compared using a combustion aerosol source. The first utilized the scanning mobility particle sizer (SMPS), while the second combined measurements from the electrical aerosol detector (EAD), which measures total aerosol length ( mm / cm 3 ) , and the condensation particle counter (CPC). Poor agreement was found between EAD/CPC and SMPS data when mean particle size was used as a basis for comparison but good agreement was found between EAD and SMPS data when total aerosol length was used as a basis for comparison. The largest contribution to the poor correlation between the two methods was the difference in concentration measured by the SMPS and the CPC. This paper examines the influence of both diffusion losses and nanoparticle aggregate mobility on these results, which also suggest that morphology, charging and composition may be contributing factors.
Distribution of periodic orbits of symbolic and Axiom A flows

Indeed, Margulis [lo] announced that for the geodesic flow on a d-dimensional compact manifold of curvature - 1 the number of periodic orbits 7 with (minimal) period r(1) I x is asymptotic to ecd-‘jx/(d - 1)x. This result bears a striking resemblance to the prime number theorem. Parry and Pollicott [12], following earlier work by Bowen [2, 41, generalized Margulis’ theorem to weakly mixing Axiom A flows, proving that # { 7: r(1) I x} eh*/hx, where h is the topological entropy of the flow. Sarnak [15] has related results for the horocycle flow. Bowen [3] and Parry [ll] proved analogues of the Dirichlet density theorem for mixing Axiom A flows, e.g., if 7(G) represents the integral of the continuous function G over one period of 7, then Z roj s ,7(G)/~(l) - (eh”/hx)lG dji, where ji is the invariant probability measure of maximum entropy. This paper pursues an altogether different analogy, this between the distribution problems for periodic orbits of Axiom A and symbolic flows and those of classical probability theory. This analogy leads to theorems which apparently have no counterparts in number theory. Moreover, it leads to techniques quite different from those commonly used in studying periodic orbits: in particular, there is no use of zeta functions or any of the attendant Tauberian theorems. We do not believe that the main results of this paper can be obtained by analyzing zeta functions. These results do, however, make use of the groundwork done by Bowen in [4], which reduces
A DNMT3A mutation common in AML exhibits dominant-negative effects in murine ES cells

Somatic heterozygous mutations of the DNA methyltransferase gene DNMT3A occur frequently in acute myeloid leukemia and other hematological malignancies, with the majority (∼60%) of mutations affecting a single amino acid, Arg882 (R882), in the catalytic domain. Although the mutations impair DNMT3A catalytic activity in vitro, their effects on DNA methylation in cells have not been explored. Here, we show that exogenously expressed mouse Dnmt3a proteins harboring the corresponding R878 mutations largely fail to mediate DNA methylation in murine embryonic stem (ES) cells but are capable of interacting with wild-type Dnmt3a and Dnmt3b. Coexpression of the Dnmt3a R878H (histidine) mutant protein results in inhibition of the ability of wild-type Dnmt3a and Dnmt3b to methylate DNA in murine ES cells. Furthermore, expression of Dnmt3a R878H in ES cells containing endogenous Dnmt3a or Dnmt3b induces hypomethylation. These results suggest that the DNMT3A R882 mutations, in addition to being hypomorphic, have dominant-negative effects.
A stochastic reinforcement learning algorithm for learning real-valued functions

Abstract Most of the research in reinforcement learning has been on problems with discrete action spaces. However, many control problems require the application of continuous control signals. In this paper, we present a stochastic reinforcement learning algorithm for learning functions with continuous outputs using a connectionist network. We define stochastic units that compute their real-valued outputs as a function of random activations generated using the normal distribution. Learning takes place by using our algorithm to adjust the two parameters of the normal distribution so as to increase the probability of producing the optimal real value for each input pattern. The performance of the algorithm is studied by using it to learn tasks of varying levels of difficulty. Further, as an example of a potential application, we present a network incorporating these stochastic real-valued units that learns to perform an underconstrained positioning task using a simulated 3 degree-of-freedom robot arm.