bluuebunny/crossref_metadata_2025_split huggingface dataset:
Counteraction by repetitive daily exposure to static magnetism against sustained blockade of N‐methyl‐D‐aspartate receptor channels in cultured rat hippocampal neurons
Authors: Hirai Takao , Taniura Hideo , Goto Yasuaki , Tamaki Keisuke , Oikawa Hirotaka , Kambe Yuki , Ogura Masato , Ohno Yu , Takarada Takeshi , Yoneda Yukio 
Published: April 2005

AbstractIn rat hippocampal neurons cultured with the antagonist for N‐methyl‐D‐aspartate (NMDA) receptors dizocilpine (MK‐801) for 8 days in vitro (DIV), a significant decrease was seen in the expression of microtubule‐associated protein‐2 (MAP‐2) as well as mRNA for both brain‐derived neurotrophic factor (BDNF) and growth‐associated protein‐43 (GAP‐43), in addition to decreased viability. MK‐801 not only decreased the expression of the NR1 subunit of NMDA receptors but also increased NR2A expression, without affecting NR2B expression. Repetitive daily exposure to static magnetic fields at 100 mT for 15 min led to a decrease in the expression of MAP‐2, without significantly affecting cell viability or the expression of neuronal nuclei (NeuN) and GAP‐43. However, the repetitive magnetism prevented decreases in both BDNF mRNA and MAP‐2 and additionally increased the expression of NR2A subunit, without altering NR1 expression in neurons cultured in the presence of MK‐801. Repetitive magnetism was also effective in preventing the decrease by MK‐801 in the ability of NMDA to increase intracellular free Ca2+ ions, without affecting the decrease in the maximal response. These results suggest that repetitive magnetism may at least in part counteract the neurotoxicity of MK‐801 through modulation of the expression of particular NMDA receptor subunits in cultured rat hippocampal neurons. © 2005 Wiley‐Liss, Inc.
Study of the Segmental Dynamics in Semi‐Crystalline Poly(lactic acid) using Mechanical Spectroscopies
Authors: Mano João F. 
Published: April 2005

AbstractSummary: The glass transition of poly(L‐lactic acid) (PLLA) occurs not far above typical service temperatures (room or body temperatures) which has consequences on the material properties during its use, such as damping or the occurrence of structural relaxation. This work aims at characterising the glass transition dynamics of a semi‐crystalline PLLA using both dynamic mechanical analysis (DMA) and thermally stimulated recovery (TSR). The main viscoelastic parameters have been characterised at 1 Hz using DMA and the master curve obtained after isothermal experiments at different temperatures provided a full picture of the solid‐state rheological behaviour throughout a wide frequency range. The activation energies calculated from the shift factors agree with the TSR ones, exhibiting a maximum near the Tg. Above the Tg, the results can be described with the WLF model. In the glassy state, the activation energy decreases with decreasing temperatures being always higher than the prediction of the Adam and Gibbs theory, at least down to temperatures 30 °C below the Tg. This suggests the existence of non‐arrested degrees of freedom in the glassy state, being consistent with the existence of a significant degree of cooperativity in the TSR results.Temperature dependence of the apparent activation energy across the glass transition.magnified imageTemperature dependence of the apparent activation energy across the glass transition.
Observation of Regime III Crystallization in Polyethylene/Montmorillonite Nanocomposites
Authors: Xu Jun‐Ting , Zhao Yan‐Qin , Wang Qi , Fan Zhi‐Qiang 
Published: April 2005

AbstractSummary: Exfoliated and intercalated polyethylene/montmorillonite (PE/MMT) nanocomposites with high MMT content were prepared by in situ polymerization. The isothermal crystallization kinetics of the nanocomposites were analyzed with Lauritzen–Hoffman regime theory. Regime III crystallization, which is difficult to observe in linear polyethylene, appears in the PE/MMT nanocomposites. The broader temperature range of regime III crystallization in PE/MMT nanocomposites shows that the mobility and reptation ability of the PE chains are greatly reduced by the MMT, especially in the intercalated nanocomposite.Plots of ln K/n + U*/R(Tc − T0) against 1/Tc(ΔT)f for the intercalated and exfoliated PE/MMT nanocomposites.magnified imagePlots of ln K/n + U*/R(Tc − T0) against 1/Tc(ΔT)f for the intercalated and exfoliated PE/MMT nanocomposites.
Fabrication of Metal‐Block‐Copolymer Composite Films by a Palladium‐Catalyzed Electroless Nickel‐Plating Process
Authors: Cheng Ya‐Jun , Renker Sabine , Sun Zaicheng , Gutmann Jochen S. 
Published: April 2005

AbstractSummary: Homogeneous films of PI‐b‐PDMAEMA are prepared on top of silicon (100) substrates. The free film surface shows microdomains of PDMAEMA within a PI matrix. These microdomains act as templates for the highly site‐selective synthesis of metal nanoparticles via palladium‐catalyzed electroless nickel plating. The particle formation is studied by atomic force microscopy in tapping mode and implications for a redox reaction and a nanoparticle growth mechanism on the surface of nanopatterned films are discussed.Chemical structure of the PI‐b‐PDMAEMA copolymer and AFM phase image of a PI‐b‐PDMAEMA film on Si (100) substrate.magnified imageChemical structure of the PI‐b‐PDMAEMA copolymer and AFM phase image of a PI‐b‐PDMAEMA film on Si (100) substrate.
Living Ring‐Opening Polymerization of Cyclic Esters with Epoxide‐Derived Titanium Alkoxides
Authors: Asandei Alexandru D. , Saha Gobinda 
Published: April 2005

AbstractSummary: The TiIIICp2Cl‐catalyzed radical ring opening of epoxides produces Ti alkoxides which initiate the ring‐opening polymerization of ε‐caprolactone. A linear dependence of $\overline M _{\rm n}$ on conversion, linear kinetics, low $\overline M _{\rm w} /\overline M _{\rm n}$ values, and the synthesis of block copolymers demonstrate a living process, while NMR spectroscopy confirms the presence of the initiator chain end. Epoxides are thus introduced as a new class of initiators for the Ti‐catalyzed living ring‐opening polymerization of cyclic esters.The TiCp2Cl‐catalyzed radical ring opening of epoxides followed by the initiation of the living ring‐opening polymerization of ε‐caprolactone.magnified imageThe TiCp2Cl‐catalyzed radical ring opening of epoxides followed by the initiation of the living ring‐opening polymerization of ε‐caprolactone.
Xanthate‐Mediated Living Radical Polymerization of Vinyl Acetate in Miniemulsion
Authors: Simms Ryan W. , Davis Thomas P. , Cunningham Michael F. 
Published: April 2005

AbstractSummary: The MADIX/RAFT mechanism, employing a xanthate as the reversible chain‐transfer agent, has been shown to facilitate the living radical polymerization of vinyl acetate in miniemulsion. Methyl (ethoxycarbonothioyl)sulfanyl acetate (MESA) successfully mediated the polymerization which was initiated with either of the water‐soluble initiators 2,2′‐azobis{2‐[1‐(2‐hydroxyethyl)‐2‐imidazolin‐2‐yl]propane} dihydrochloride (VA‐060) or 2,2′‐azobis[2‐(2‐dimidazolin‐2‐yl)propane] dihydrochloride (VA‐044). The polymerizations exhibit living characteristics, demonstrated by the evolution of molecular weight distributions. The formulation of the miniemulsion produced stable latexes with no coagulum.The number‐average molecular weight and PDI as a function of monomer conversion for the RAFT miniemulsion polymerization of vinyl acetate.magnified imageThe number‐average molecular weight and PDI as a function of monomer conversion for the RAFT miniemulsion polymerization of vinyl acetate.
Preheating Sensitization of a TATB Composition Part Three: Sensitization for Various Stimuli, Interpretation and Conclusions
Authors: Belmas Robert , Gautier Laurent , David Claire , Picart Didier , Le Gallic Christian , Lambert Philippe 
Published: April 2005

AbstractPreheating induced sensitization has been commonly studied in the frame of SDT but a complete analysis in terms of pyrotechnic safety needs to take into account other kinds of stimuli like “moderate” mechanical ones (crushing, drops…︁), new thermal fluxes or combined insults. We present the results of connected studies and propose sensitization mechanisms based on these data and on previous chemical and microstructure characterizations.
Ignition and Growth Modeling of LX‐17 Hockey Puck Experiments
Authors: Tarver Craig M. 
Published: April 2005

AbstractDetonating solid plastic bonded explosives (PBX) formulated with the insensitive molecule triaminotrinitrobenzene (TATB) exhibit measurable reaction zone lengths, curved shock fronts, and regions of failing chemical reaction at abrupt changes in the charge geometry. A recent set of “hockey puck” experiments measured the breakout times of diverging detonation waves at ambient temperature LX‐17 (92.5% TATB plus 7.5% Kel‐F binder) and the breakout times at the lower surfaces of 15 mm thick LX‐17 discs placed below the detonator‐booster plane. The LX‐17 detonation waves in these discs grow outward from the initial wave leaving regions of unreacted or partially reacted TATB in the corners of these charges. This new experimental data is accurately simulated for the first time using the Ignition and Growth reactive flow model for LX‐17, which is normalized to detonation reaction zone, failure diameter and diverging detonation data. A pressure‐cubed dependence for the main growth of reaction rate yields excellent agreement with experiment, while a pressure‐squared rate diverges too quickly and a pressure‐quadrupled rate diverges too slowly into the LX‐17 below the booster equatorial plane.
Laser Ignition of Pyrotechnics – Effects of Wavelength, Composition and Confinement
Authors: Ahmad Sheikh Rafi , Russell David Anthony 
Published: April 2005

AbstractIgnition tests were carried out using three different laser systems and three different pyrotechnic compositions. Pyrotechnic materials investigated are: sulfur/charcoal/potassium nitrate based composition (gunpowder, GP), Shellac binder‐based boron/potassium nitrate composition (SR 44) and acaroid resin binder based magnesium/potassium nitrate composition (SR 371C). The laser sources were the multimode output from an Ar‐ion laser (λ=500 nm average), a high‐power commercial diode laser (λ=784 nm) and a small laser diode operating at around the same wavelength but controlled by a customized electronic circuitry. Lasers operating in the visible wavelength range provided more reproducible and quicker ignition than the infrared output from the diode lasers. It was found that unconfined gunpowder exhibits more reproducible ignition for both the visible and the infrared wavelengths compared to the other two compositions. The composition based on magnesium, SR 371C appeared to be very sensitive to laser intensity variations and gave erratic and therefore, irreproducible ignition delay times. The threshold laser energies to initiate reproducible ignition for the different wavelengths were measured and ignition maps were constructed. From these maps, the required laser power density for any value of the ignition delay time, i.e. laser energy density was determined. Tests were also conducted on gunpowder samples, partially confined in a modified pyrogen igniter capsule and a small laser diode. The diode was operated in single pulse mode using a current surge, which was much higher than the recommended value for CW operation. This provided ~1 W pulses at the end of a 1 mm diameter fiber optic cable and caused reproducible ignition in the semi‐confined pyrotechnic bed within the capsule. The threshold ignition energy under semi‐confined conditions was found to be substantially less than that required in the unconfined environment under similar experimental conditions.
Experimental and Theoretical Study of 1,5‐Diamino‐4‐H‐1,2,3,4‐Tetrazolium Perchlorate
Authors: Drake Gregory W. , Hawkins Tommy W. , Boatz Jerry , Hall Leslie , Vij Ashwani 
Published: April 2005

AbstractThe synthesis and characterization of 1,5‐diamino‐1,2,3,4‐tetrazolium perchlorate were carried out. Experimental evidence strongly supports the protonation of a nitrogen atom of the tetrazole ring, including the structure observed in a single crystal X‐ray diffraction study of the title compound. Quantum chemical calculations were performed at the CCSD(T)/6‐311G(2df, p)//MP2/6‐311G(d, p) level of theory to determine the relative energies of all possible N‐protonated structures of the 1,5‐diamino‐1,2,3,4‐tetrazole ring. The predicted geometry of the most stable isomer compares favorably with the experimentally observed structure.
Surgical treatment of hyperparathyroidism
Authors: Aun Frederico , Egdahl Richard H. 
Published: April 2005

AbstractA dramatic rise in the number of diagnosed cases of hyperparathyroidism has been accompanied by significant progress in diagnostic and management techniques. Indications for parathyroid surgical exploration have been established for cases presenting with hypercalcemia and any of several clinical syndromes. Asymptomatic or mildly symptomatic patients with the disease can be followed for longer intervals prior to surgery, but surgical treatment is recommended. Normocalcemic hyperparathyroidism with repeated renal stones exists as a disease entity and further investigation is needed to determine guidelines for operative treatment. Surgery is reserved for medically intractable cases in secondary hyperparathyroidism.The surgical strategy should be based on the identification of all glands and, with few exceptions, only abnormal tissue should be resected. Mediastinal explorations are rarely needed and should always be preceded by careful localization studies. Surgical results are generally good, with low recurrence rates if definitive surgery is possible. Mortality and morbidity rates are also very low and, while the most common postoperative complication is temporary hypocalcemia, vocal cord paralysis is a rare but debilitating one.
The important influence of arterial blood gases on the prognosis of congenital diaphragmatic hernia
Authors: Boix‐Ochoa J. , Natal A. , Canals J. , Seijo G. , Peguero G. 
Published: April 2005

AbstractArterial blood gases were measured preoperatively and postoperatively in 20 newborn infants with congenital diaphragmatic hernia during spontaneous breathing or assisted ventilation. Of these 20 patients, 11 survived and 9 died. Arterial blood Pco2 levels of survivors (mean of 44.3 ± 7.9 mm Hg) were significantly lower (p <0.01) than those of nonsurvivors (mean of 61.3±15.4 mm Hg). Arterial blood Po2 levels of survivors (mean of 307.9+142.3) were very significantly higher (p<0.001) than those of nonsurvivors (mean of 49.8±14.2). All but 2 survivors had Po2 levels greater than 230 mm Hg in the preoperative period during breathing of 100% oxygen, while none of those who died had Po2 levels higher than 80 mm Hg.From these results, it is concluded that the prognosis is excellent if the arterial blood Po2 and Pco2 levels are normal preoperatively, or if they can be brought into an acceptable range (Po2 above 230 mm Hg, Pco2 below 70 mm Hg) with oxygen therapy and/or assisted ventilation. On the other hand, if arterial Po2 cannot be raised to the acceptable level by respiratory therapy, a fatal outcome should be anticipated.
A review of 128 cases of posterior mediastinal goiter
Authors: De Andrade Mariano A. 
Published: April 2005

AbstractIn 9,100 thyroid operations performed between 1935 and 1975, the author treated over 1,300 patients with intrathoracic goiters, 128 of whom had posterior mediastinal goiters. In all patients, the posterior mediastinal goiter arose from the thyroid gland in the neck. The main symptoms were those resulting from compression of the trachea, bronchi, esophagus, and great vessels. Chest x‐rays showing displacement of mediastinal structures were the most helpful diagnostic studies. It was possible to remove the goiter entirely through a cervical approach in 122 of the 128 patients. Six patients required a combined cervicothoracic approach after exploration through the neck showed that it was not possible to safely perform a thyroidectomy. There was only one death in this group of 128 patients, all of whom were over the age of 50.
Postoperative ascending cholangitis following portoenterostomy for biliary atresia: Measures for control
Authors: Lilly John R. , Hitch David C. 
Published: April 2005

AbstractTwenty‐five patients with biliary atresia were treated by a modification of Kasai's hepatic portoenterostomy operation. The midportion of the Roux‐en‐Y bilioenteric conduit was exteriorized as a Mikulicz anastomosis. This type of biliary reconstruction permitted precise analysis of the biliary drainage, including determinations of the concentrations and types of microorganisms infecting the bilioenteric conduit before, during, and after episodes of cholangitis.Cholangitis was a universal complication in all patients having sustained bile drainage and, paradoxically, was a hallmark of a successful operation. Attacks of infection were frequent for the first 6 to 9 months. There was no correlation between types and amounts of bacteria in the bile drainage and episodes of cholangitis. Therefore, bile culture data were of no use in selection of specific antibiotic treatment. Nevertheless, antibiotics effective against enteric microorganisms usually cured the infection promptly. Maneuvers that may be helpful in lessening the incidence and severity of cholangitis during this early period consist of exteriorization of the bilioenteric conduit to ensure unimpeded flow of bile, use of choleretic agents, and preventive use of antibiotics.A second period in which patients were at risk occurred 1–2 years after operation. In this instance, cholangitis was almost invariably a consequence of simple mechanical obstruction of the bilioenteric conduit. Early crushing of the Mikulicz spur and postponement of closure of the bilioenteric conduit were found to be important in prevention of cholangitis during this period.
Preliminary trial of a retroperitoneal approach for modified selective distal splenorenal shunt
Authors: Pera C. , Visa J. , Rodes J. , Teres J. 
Published: April 2005

AbstractA modified selective splenorenal shunt without “portal‐azygos disconnection” through the left retroperitoneal approach was performed in 13 patients with cirrhosis of the liver and acute massive variceal hemorrhage. The anastomosis was end‐to‐side in 9 patients and end‐to‐end in 4 patients. All patients survived the operation. The post‐operative course was extraordinarily benign; none of the patients developed clinical manifestations or biological evidence of hepatic dysfunction attributable to the operation. The only patient who died had an acute massive hemorrhage in the third postoperative week. None of the 12 surviving patients experienced further gastrointestinal bleeding. Dissection of the splenic and renal veins through the posterior retroperitoneal approach is technically easy. It may be the only alternative approach for portosystemic decompression in patients with dense intra‐abdominal adhesions from previous operations involving the biliary tree or the upper gastrointestinal tract.The retroperitoneal approach for modified selective splenorenal portosystemic decompression is an effective method in the treatment and prevention of gastroesophageal bleeding in cirrhotic patients.
Heterogeneity of gastrointestinal hormones
Authors: Rehfeld Jens F. 
Published: April 2005

AbstractThe molecular heterogeneity of gastrointestinal hormones is reviewed. The phenomenon of heterogeneity is characteristic of all secreted proteins, including macromolecules like albumin and immunoglobulins, as well as protein and polypeptide hormones. Heterogeneity reflects basal mechanisms involved in ribosomal biosynthesis, posttranslational cleavage and modification, as well as degradation in peripheral tissue of biologically important substances. Thus far, all gastrointestinal hormones have displayed heterogeneity. The degree of heterogeneity reported has varied for the individual gut hormones. The most extensively studied hormones, such as gastrin and insulin, have displayed a high degree of heterogeneity, and similar heterogeneity will probably emerge for the remaining hormones when they have been studied in greater detail. Based on the extent of molecular difference, a distinction between macro‐ and microheterogeneity is proposed. Macroheterogeneity indicates a difference in molecular size of several (two or more) amino acids, while microheterogeneity indicates modifications of single amino acid residues. Molecular heterogeneity has implications regarding extraction, measurement, and evaluation of the action of the individual gut hormones. Thus, extraction may require several different procedures in order to identify all the molecular forms of a hormone. Measurement in blood and other biological fluids requires careful evaluation of the specificity of the assays towards the different molecular forms of a hormone in order to evaluate its physiological role. Consequently, understanding of the significance of gut hormones in gastrointestinal disease requires further clarification of their heterogeneous nature.
Radioimmunoassay of gastrointestinal hormones
Authors: Rayford Phillip L. , Hejtmancik Kelly , Thompson James C. 
Published: April 2005

AbstractSince 1968, radioimmunoassays have been developed for major gastrointestinal hormones (gastrin, cholecystokinin, secretin, and gastric inhibitory peptide) and for many substances in the gastrointestinal tract that await full hormonal status (vasoactive intestinal peptide, motilin, pancreatic polypeptide, enteroglucagon, serotonin, prostaglandins, inter alia). Although reports between laboratories on the circulating levels of gastrin and gastric inhibitory polypeptide are in relatively good agreement, wide discrepancies exist in reported values of secretin and cholecystokinin. Reports on qualitative responses of these hormones to various stimuli, however, appear to be consistent between laboratories. A review of some of the studies of radioimmunoassay techniques for gastrointestinal hormones permits analysis of some of the technical problems that can be encountered.