bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mobility of radicals in zeolite catalysts: Molecular motion studied by muon spectroscopy
Authors: Rhodes Christopher J. , Butcher Estelle C. , Morris Harry , Reid Ivan D. 
Published: May 2005

AbstractActivation parameters for the surface dynamics of radicals produced by the addition of muonium to the unsaturated organic substrates cyclopentene, benzene, tetramethylethylene [2,3‐dimethylbut‐2‐ene (TME)] and 2,3‐dimethylbuta‐1,3‐diene (DMBD) adsorbed in the zeolites Na‐mordenite and NaX and on silica have been determined by means of transverse‐field muon spin rotation spectroscopy. This allows the study of the influence of adsorption by the different surfaces on these parameters. The temperature dependences of the muon hyperfine couplings were also studied and were found to be highly sensitive to the type of catalyst, and so to the nature of the adsorption site.
Anomeric conformations of six‐membered cyclic aminoxyl radicals with a β‐alkoxyl substituent
Authors: Zhang Yong‐Kang , Janzen Edward G. , Kotake Yashige 
Published: May 2005

AbstractThe addition reactions of CH3(CH2)3O·, (CH3)2CHCH2O·, (CH3)2CHCH2CH2O·, (CH3)3CO· and (CH3)2C(CN)O· radicals to a novel six‐membered cyclic nitrone, 6,6‐dimethyl‐3,4,5,6‐tetrahydropyridine N‐oxide (M2PyO), generate the corresponding 6‐alkoxyl‐2,2‐dimethylpiperidine‐1‐oxyl aminoxyl (nitroxide) spin adducts. In benzene solution at room temperature, the preferential conformation of these spin adducts appears to be the anomeric conformer with the alkoxyl group in the axial position according to EPR spectroscopic conformational analysis of these aminoxyls. The anomeric effect in these aminoxyls might be the combination of electrostatic and molecular orbital interactions.
EPR imaging in biological applications: Towards microtomography
Authors: Sotgiu A. , Placidi G. , Gualtieri G. , Tatone C. , Campanella C. 
Published: May 2005

AbstractEPR imaging and microtomography promises to be a powerful tool for the EPR spectroscopist, but the expansion of this technique was hindered by the lack of commercial apparatus. A simple modification of an existing commercial system that can reach a resolution of the order of 75 μm with a gradient of 150 mT m−1 is described. This resolution can be increased by using larger field gradients. In many biological applications this resolution is significant. As an example, the distribution of a paramagnetic probe in an amphibious egg cell is presented that permits one to distinguish the nucleus of the cell. A summary of the mathematical techniques which enable one to account for the presence of a hyperfine structure in most EPR paramagnetic probes and to increase resolution is also presented.
Dynamic behaviour of a nitroxide biradical undergoing multiple internal motions: An ESR and 13C NMR relaxation study
Authors: Chachaty Claude , Gambarelli Serge , Rassat André 
Published: May 2005

AbstractThe ESR spectra of the bis(2,2,6,6‐tetramethyl‐4‐piperidinol‐1‐oxyl) adipate biradical at several temperatures in ethanol solution were simulated, taking into account all allowed conformers corresponding to the rotational isomerism model. The probabilities of these conformers, not accessible by ESR, were derived from 13C spin relaxation measurement on the diamagnetic reduced form of the biradical. The least‐squares fits of ESR spectra provided the temperature dependence of the rates of internal motions and of the tumbling correlation time of the biradical and also an estimate of the electron spin exchange parameters.
Luminescence in cubic boron nitride doped by rare‐earth impurity
Authors: Shishonok E. M. , Philipp A. R. , Shishonok N. A. , Anichenko N. G. 
Published: May 2005

AbstractWe report shortly the observation of visible cathodoluminescence (CL) from micropowders of Eu‐doped cubic boron nitride synthesized under high‐pressure/high‐temperature conditions and also annealed in a vacuum in the temperature range from 400 to 1100 °C. The multiplet of lines due to the intra‐ 4f transitions on the Eu3+ ion is detected in spectral region from 580 to 740 nm. The fact that the main line of the multiplet has the highest intensity, and the removed degeneracy of the 7F1 and 7F2 electronic levels represented by the second and third bands of the multiplet allow the conclusion that the red luminescence is due to the Eu2O3 inclusions in the monoclinic form (probably, as nano particles) incorporated into the cBN grains. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical solution for V‐groove quantum wire with an effective potential scheme
Authors: Sadeghi E. , Khordad R. 
Published: May 2005

AbstractWe present an analytical method for calculating the energy spectra of electron and hole in V‐groove quantum wire. The carrier ground states as well as the wave functions are calculated by an effective potential model together with a suitable coordinate transformation that allows the decoupling of the two‐dimensional wave function. The result clearly indicates the strong confinement of both electrons and holes. The calculated energy of carrier and wave function by this analytical method are in good agreement with the earlier numerical investigations. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement between layers in multiple‐layer thin‐film samples
Authors: Willis James E. 
Published: May 2005

AbstractSecondary fluorescence effects are calculated and compared with the total fluorescence for multiple‐layer thin‐film samples of Fe, Ni and Fe, Ni, Cu, Cr. The ratio of secondary to total fluorescence for a given analyte is found to be greater in the system where the enhancer is in a layer which is closer to the surface. Secondary fluorescence effects are calculated for a Ni thin film on an Sn sample. Unusual acquisition conditions cause the intensity from the Ni thin film layer to exceed the intensity from a bulk sample of Ni.
Heterogeneity effects and the reliability of X‐ray fluorescence analytical results: Study on Al2O3 matrix with calcium, yttrium, gadolinium and thorium as probe elements
Authors: Agrawal R. M. , Kapoor S. K. 
Published: May 2005

AbstractSynthetic standards obtained by dry mixing of the components in appropriate proportions, when used as calibration standards in XRF analysis can be a major source of error in the analytical results, owing to the differences in the degree of their homogeneity compared with that of the sample. In an earlier study U3O8 was used as the matrix and Ca, Y, Gd and Th in the low concentration range (0–1500 ppm) as probe impurity elements. The study has now been extended to the low‐Z matrix Al2O3 using the same impurity elements as probe elements and the same concentration range. This study also clearly illustrates the incompatibility of truely homogeneous standards with standards obtained by dry mixing and grinding and corroborates the results obtained in the earlier study. However, some of the general inferences drawn earlier required modification in order to explain the results for the two matrices. The effect of binding material, which is often required for briquetting the sample into pellet form and must be mixed with the sample by dry mixing, is discussed.
Quantitative elemental analysis of thick samples by XRF and PIXE
Authors: Gil F. B. , Barreira G. , Guerra M. F. , Alves L. C. 
Published: May 2005

AbstractAn absolute quantitative analytical method without external standards has been developed for thick sample analysis by XRF and PIXE and has been applied to bronze and brass alloys. Comparisons between the results obtained and the chemical results were made and the detection limits for the determined elements were evaluated. In an Appendix a rapid calculation of the efficiency of the Ge(Hp) detector is presented.
Method for the determination of the phase fractions in solid systems by x‐ray microanalysis
Authors: Stoyanchev R. 
Published: May 2005

AbstractA method is proposed for the quantitative evaluation of area fractions of phases with different chemical compositions in solid systems, e.g. alloys, mixtures of solid solutions and phases with defined stoichiometry, ceramics and minerals. The method is based on the scanning of the surface of the sample by an electron beam and applying an energy‐dispersive x‐ray spectrometer. By using the net integral intensities of the characteristic x‐ray lines of the elements in the different phases, equations have been derived for the area fractions of an n‐phase system composed of m elements. Assuming that the phases are uniformly distributed within the sample, the practically important volume and weight fractions of the phases are expressed by the area fractions. A technique for the assessment of the elemental content in a complex sample using an electron probe is given, by using the phase fractions determined by the proposed method and the concentration data for the elements in the separate phases. The method has been tested experimentally for the determination of the area fractions in cases where the number of phases is less than or equal to the number of constituent elements.
Determination of the various phases of aluminium in steel by x‐ray fluorescence spectrometry
Authors: Klockenkämper R. , Koch K. H. 
Published: May 2005

AbstractThe total content of aluminium in steel can be determined from the Kα line in the x‐ray spectrum with a detection limit of 0.001%. However, aluminium is generally present in three phases, as metal, as nitride and as oxide; these different phases are of metallurgical significance and have to be distinguished. This is possible from their different kβ bands in the x‐ray spectrum, which were found at 1555.3 1553.9 and 1552.5 eV, respectively. The physical bandwidth of about x‐ray 7 eV, however, causes overlapping of the peaks, so that an unfolding procedure is needed. The defection limit of the different phases was determined to be 0.06% which, unfortunately, is above the region of interest for modern steel analysis. In addition, the analysis time of about 3 min is too long for use in process control, so that the classical methods for pahse determination cannot be replaced by x‐ray fluorescence analysis.
NF‐κB and NOS may play a role in human RPMI‐8402 cell apoptosis
Authors: Trubiani Oriana , Salvolini Eleonora , Vignini Arianna , D'Arcangelo Camillo , Di Primio Roberto , Mazzanti Laura 
Published: May 2005

AbstractApoptosis is a fundamental process that is required for the normal development and functioning of the immune system. It can be induced in different ways depending on cell type and acquired signal. Since the NF‐κB transcription factor complex is believed to be involved in nitric oxide‐induced apoptosis, the aim of this study was to investigate NF‐κB and nitric oxide synthase (NOS) activity during dimethyl sulphoxide (DMSO)‐dependent cell death of RPMI‐8402 human pre‐T cells. Our results show that NF‐κB activation is associated with a significant up‐regulation of NOS activity and induction of apoptosis. Furthermore, the inhibition and reversal of these effects by parthenolide treatment or DMSO removal indicate that these molecules are directly involved in the progression of cell death.
Impact of Symptom Prevalence and Symptom Burden on Quality of Life in Patients with Heart Failure
Authors: Zambroski Cheryl Hoyt , Moser Debra K. , Bhat Geetha , Ziegler Craig 
Published: May 2005

Background: Heart failure is an escalating health problem around the world. Despite significant scientific advances, heart failure patients experience multiple physical and psychological symptoms that can impact the quality of life. Aims: To determine the (1) symptom prevalence, severity, distress and symptom burden in patients with heart failure; (2) impact of age and gender on symptom prevalence, severity, distress and symptom burden; and (3) impact of symptom prevalence and symptom burden on health-related quality of life (HRQOL) in patients with heart failure. Methods: A convenience sample of 53 heart failure patients participated in this descriptive, cross-sectional design. Symptoms and HRQOL were measured using the Memorial Symptom Assessment Scale—Heart Failure and the Minnesota Living with Heart Failure Questionnaire. Results: Patients experienced a mean of 15.1 ± 8.0 symptoms. Shortness of breath and lack of energy were the most prevalent. Difficulty sleeping was the most burdensome symptom. Lower age, worse functional status, total symptom prevalence and total symptom burden predicted 67% of the variance in HRQOL. Conclusion: Patients with heart failure experience a high level of symptoms and symptom burden. Nurses should target interventions to decrease frequency, severity, distress and overall symptom burden and improve HRQOL.
Attenuation of postoperative noradrenaline need by nitric oxide inhibition using L‐NMMA
Authors: Franco‐Cereceda Anders , Holm Peter , Bredin Fredrik , Adding Christoffer 
Published: May 2005

AbstractIn the present report we describe that NG‐monomethyl‐L‐arginine acetate, a non‐specific nitric oxide synthesis inhibitor, administered at 1 mg kg–1 h–1 to a patient with critical hypotension following mitral valve surgery combined with passive containment surgery, increased the urinary output and arterial blood pressure while the need for noradrenaline was rapidly attenuated. Again increasing the noradrenaline infusion in the presence of NG‐monomethyl‐L‐arginine acetate caused a dramatic increase of the blood pressure.
Controlling postpartum hemorrhage after home births in Tanzania
Authors: Prata N. , Mbaruku G. , Campbell M. , Potts M. , Vahidnia F. 
Published: May 2005

AbstractObjectives: Determine safety of household management of postpartum hemorrhage (PPH) with 1000 μg of rectal misoprostol, and assess possible reduction in referrals and the need for additional interventions. Methods: Traditional birth attendants (TBAs) in Kigoma, Tanzania were trained to recognize PPH (500 ml of blood loss). Blood loss measurement was standardized by using a local garment, the “kanga”. TBAs in the intervention area gave 1000 μg of misoprostol rectally when PPH occurred. Those in the non‐intervention area referred the women to the nearest facility. Results: 454 women in the intervention and 395 in the non‐intervention areas were eligible. 111 in the intervention area and 73 in the non‐intervention had PPH. Fewer than 2% of the PPH women in the intervention area were referred, compared with 19% in the non‐intervention. Conclusion: Misoprostol is a low cost, easy to use technology that can control PPH even without a medically trained attendant.
Maternal and perinatal outcome of pregnancies complicated by cardiac disease
Authors: Abdel‐Hady E.‐S. , El‐Shamy M. , El‐Rifai A.‐A. , Goda H. , Abdel‐Samad A. , Moussa S. 
Published: May 2005

AbstractObjective: The aim of this study was to assess the maternal and perinatal outcome of pregnancies complicated by cardiac disease in a tertiary care center in Egypt. Methods: During a 1‐year period, a total of 86 pregnant women with cardiac disease were admitted. Maternal and perinatal morbidity and mortality were calculated and compared with a control group. Results: Seventy‐seven (89.5%) patients were due to rheumatic affection, and 60 patients were classified as NYHA classes I–II. There was one case of maternal mortality (1.16%), and 10 other cases developed life‐threatening complications. Two perinatal mortalities (2.32%) occurred in this series. Birth weight of babies born to mothers with functional classes III and IV were significantly lower than those of functional classes I–II and control group. Conclusion: Rheumatic heart disease with pregnancy is still predominant in Egypt. Maternal and perinatal morbidity and mortality are strongly correlated to maternal cardiac functional classification.
Hypothalamic‐pituitary‐gonadal function in adolescent females with beta‐thalassemia major
Authors: Al‐Rimawi H.S. , Jallad M.F. , Amarin Z.O. , Obeidat B.R. 
Published: May 2005

AbstractObjective: To evaluate the function of the hypothalamic‐pituitary‐gonadal axis in adolescent female patients with beta‐thalassemia major. Materials and methods: A prospective study of the function of the hypothalamic‐pituitary‐gonadal axis function of 31 beta‐thalassemia major females aged between 13 and 22 years and in 12 control females aged between 12 and 22 years. All were treated at Princess Rahma Teaching Hospital, Irbid, Northern Jordan between April 2001 and April 2003. Results: Of the 31 beta‐thalassemia major females, 13 (41.9%) had delayed puberty. Hypothalamic‐pituitary‐ovarian axis dysfunction was found in 15 patients (48.4%). Twelve patients (38.7%) had hypogonadotropic hypogonadism and 5 (16.1%) had ovarian failure. High levels of serum ferritin were significantly higher in patients with delayed puberty. Conclusion: Pituitary and ovarian dysfunction are common problems in beta‐thalassemia major patients. The main possible cause is iron overload. This stresses the need for intensive and regular use of chelation therapy to prevent damage to the hypothalamic‐pituitary‐ovarian axis.
Flexibility and technology choice in gas fired power plant investments
Authors: Näsäkkälä Erkka , Fleten Stein‐Erik 
Published: May 2005

AbstractThe value of a gas fired power depends on the spark spread, defined as the difference between the price of electricity and the cost of gas used for the generation of electricity. We model the spark spread using a two‐factor model, allowing mean‐reversion in short‐term variations and uncertainty in the equilibrium price to which prices revert. We analyze two types of gas plants: peak and base load plants. A peak load plant generates electricity when spark spread exceeds emission costs, whereas a base load plant generates electricity at all levels of spark spread. A base load plant can be upgraded to a peak load plant. First, we find the upgrading threshold for a base load plant. The upgrading threshold gives the optimal type of gas plant as a function of spark spread. Second, we calculate building threshold for the investment costs. When the investment costs are below the threshold it is optimal to build the plant with the previously solved optimal technology. In the numerical example, we illustrate how our model can be used when investments in gas fired power plants are considered.
Magnetostratigraphic dating of the Donggutuo and Maliang Paleolithic sites in the Nihewan Basin, North China
Authors: Wang Hongqiang , Deng Chenglong , Zhu Rixiang , Wei Qi , Hou Yamei , Boëda Eric 
Published: May 2005

AbstractA detailed magnetostratigraphic investigation, coupled with rock-magnetic studies, was carried out on a lacustrine sequence in the eastern Nihewan Basin, Northern China, which contains the Donggutuo and Maliang Paleolithic sites. Magnetite and hematite were identified as the main carriers for the characteristic remanent magnetizations. Magnetostratigraphic results show that the lacustrine sequence recorded the late Matuyama and Brunhes chrons. Furthermore, the Maliang artifact layer occurs just below the Brunhes/Matuyama boundary, and the Donggutuo artifact layer is just below the Jaramillo onset. Therefore, the age of the Maliang and Donggutuo artifact layers can be definitely estimated to be about 0.78 myr and 1.1 myr, respectively. These two paleomagnetic ages, coupled with previously obtained paleomagnetic data of the Majuangou, Xiaochangliang, Banshan, Lantian, and Xihoudu Paleolithic sites, suggest an expansion and lengthy flourishing of human groups from northern to north-central China during the entire Early Pleistocene.
The effect of malnutrition on the pattern of growth in the rat kidney and the renal response to acidosis
Authors: Fraser H. S. , Alleyne G. A. O. 
Published: May 2005

1. The kidneys of normal rats were analysed for water, fat, protein, RNA and DNA, at 10, 21 and 36 d after birth. The effects on growth caused by two types of malnutrition were investigated.2. An increase in the RNA:DNA ratio was demonstrated between 10 and 36 d, contrary to previous evidence that this ratio is fixed at birth.3. Energy deficiency during the first 21 d of life resulted mainly in fewer kidney cells, whereas protein-energy deficiency between 21 and 36 d resulted mainly in a smaller cellular content of RNA and protein.4. In response to metabolic acidosis, both groups of malnourished rats increased urinary excretion of ammonia and there was enhanced gluconeogenesis in vitro; the basal rate of gluconeogenesis was lower in the protein-energy-deficient rats than in the controls.5. Protein-energy-deficient rats did not exhibit the renal hypertrophy shown by the control rats in response to acidosis.
Protein digestion in the intestine of sheep
Authors: Ben-Ghedalia D. , Tagari H. , Bondi A. , Tadmor A. 
Published: May 2005

1. The rate of flow of digesta along the intestinal tract, and particularly the changes occurring in proteins during their passage through the intestine were determined in six rams; each animal was fistulated with three cannulas which involved six different sites of the intestine. Cr2O3 was used as a marker substance to measure the rate of flow of the digesta.2. In the sections of the intestine from 1 to 15 m posterior to the pylorus the amounts of water, dry matter and total nitrogen decreased gradually as a result of their absorption through the intestinal wall. The region of the intestine situated at a distance of 7–15 m from the pylorus was more active with respect to the absorption of N, whereas water and dry matter were adsorbed to a greater extent in the region from 1 to 7 m from the pylorus.3. The only part of the intestine in which substantial increases of water, dry matter and total N were found was the section immediately distal to the pylorus, and these increases were caused by the inflow of bile, and pancreatic and duodenal juices. The net increase found beyond the entry of the common bile duct was 2.7 g protein N and 2.0 g non-protein N (NPN)/24 h.4. The activities of trypsin, chymotrypsin and carboxypeptidase A and the ratio α-NH2 NPN: protein N increased from the pylorus up to a distance of 7 m and decreased again from this point to a distance of 15 m from the pylorus.5. In the sections of the intestine between 1 and 3 and between 3 and 7 m distant from the pylorus the extent of proteolysis exceeded considerably that of absorption of amino acids through the intestinal wall. This was concluded from the decrease in the rate of flow of protein amino acids (by 31% between 1 and 3 m distant from the pylorus and by 34% between 3 and 7 m) and the simultaneous increase in non-protein amino acids (by 20% in the region between 1 and 3 m) or no change in non-protein amino acids (between 3 and 7 m).6. The relatively greater decrease in non-protein amino acids (by 57%) compared with that of protein amino acids (by 41%) occurring in the section 7 to 15 m distant from the pylorus showed that this is an area of most intensive absorption of amino acids.7. In the lower section of the intestine, from 15 to 25 m distant from the pylorus, the total amount of amino acids showed almost no change; probably a net effect of loss and gain of amino acids mainly due to microbial activities. Increases in the dehydrogenase activity suggested enhancement of bacterial activity in this lower region of the intestine.8. The supply of essential amino acids to the tissues of sheep is improved, compared with the amino acid composition of the diet, as the result of ruminal biosynthesis of essential amino acids and ruminal degradation of non-essential amino acids and preferential absorption of essential amino acids through the intestinal wall, particularly in the section of most intensive absorption, 7–15 m distant from the pylorus.