bluuebunny/crossref_metadata_2025_split huggingface dataset:
J‐model for magnetism and superconductivity of triangular, kagome, and related spin lattice systems
Authors: Yamanaka Shusuke , Yamaki Daisuke , Takeda Ryo , Nagao Hidemi , Yamaguchi Kizashi 
Published: August 2004

AbstractA previous theoretical model, the J‐model, for superconductivity of triangular, Kagome, and related spin lattice systems, has been reinvestigated in relation to the recent discovery of superconductivity in NaxCoO2 · yH2O. To elucidate a possible interrelationship between magnetism and superconductivity, effective exchange integrals (Jab) for magnetic clusters with triangular lattices are calculated by ab initio generalized Hartree–Fock (GHF) and generalized density functional theory (GDFT) methods through the use of general spin orbitals (GSO). From the computational results, several model Hamiltonians such as J‐ and t–J‐models are derived for elucidation of the electronic properties of molecule‐based materials with triangular, Kagome, and related spin lattice systems. The theoretical possibilities of spin‐mediated superconductivity are examined on the basis of the J‐model in the intermediate region for metal–insulator transitions. The interplay of spin exchange or spin fluctuation and other effects for superconductivity of strong correlation systems is also feasible both on theoretical and on experimental grounds, supporting the cooperative mechanism toward high‐Tc superconductivity. The implications of the calculated results are discussed in relation to theoretical possibilities of non‐Bardeen–Cooper–Schrieffer (BCS) superconductivity on the basis of cooperative mechanisms of electron correlation (or spin fluctuation) and multi‐band effects in magnetic clusters with icosidodecahedral and related symmetries. Noncoplanarity of spins in molecule‐based magnets is finally discussed to elucidate spin chirality, which is related to a persistent electron current and anomalous Hall effect in triangular and Kagome spin lattices. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Testing graphs for colorability properties*
Authors: Fischer Eldar 
Published: August 2004

AbstractLet P be a property of graphs. An ϵ‐test for P is a randomized algorithm which, given the ability to make queries whether a desired pair of vertices of an input graph G with n vertices are adjacent or not, distinguishes, with high probability, between the case of G satisfying P and the case that it has to be modified by adding and removing more than ϵ() edges to make it satisfy P. The property P is called testable if for every ϵ there exists an ϵ‐test for P whose total number of queries is independent of the size of the input graph. Goldreich, Goldwasser, and Ron [Property testing and its connection to learning and approximation, J ACM 45 (1998), 653–750] showed that certain graph properties, like k‐colorability, admit an ϵ‐test. In Alon, Fischer, Krivelevich, and Szegedy [Efficient testing of large graphs, Combinatorica 20 (2000), 451–476] a first step towards a logical characterization of the testable graph properties was made by proving that all first order properties of type “∃∀” are testable, while there exist first‐order graph properties of type “∃∀” that are not testable. For proving the positive part, it was shown that all properties describable by a very general type of coloring problem are testable. While this result is tight from the standpoint of first order expressions, further steps towards the characterization of the testable graph properties can be taken by considering the coloring problem instead. It is proven here that other classes of graph properties, describable by various generalizations of the coloring notion used in Alon et al. [Combinatorica 20 (2000), 451–476], are testable, showing that this approach can broaden the understanding of the nature of the testable graph properties. The proof combines some generalizations of the methods used in Alon et al. with additional methods. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Monte Carlo calculation using a personal computer for electron probe microanalysis
Authors: Osada Yoshio 
Published: August 2004

AbstractMonte Carlo simulation for calculating x‐ray spectra under electron impact is carried out by a personal computer. Reduction of the CPU time by reducing the number of incident electrons for calculation is performed. One of the methods used to reduce the number of incident electrons to obtain the results within an acceptable error is provided. We limit the present report to five typical compounds: an oxide (Al2O3), a nitride (TiN), a carbide (Al4C3), a light–light element compound (BN), and a heavy–light element compound (PbS). We calculate the relative x‐ray intensity generated from the five compounds listed above with the change of the number of the incident electrons. The calculated x‐ray intensity is then converted into the mass % by the ZAF method. Comparisons are made between the calculation and experiment for Al4C3 and PbS. It is found that the present Monte Carlo method is useful for investigating a relationship between the number of incident electrons and the acceptable error. The results of 150 incident electrons can be applied in practical analysis, and the calculation time is less than 2 min. Copyright © 2004 John Wiley & Sons, Ltd.
Study of the deterioration of sandstone due to acid rain and humid SO2 gas
Authors: Holynska Barbara , Gilewicz‐Wolter Jolanta , Ostachowicz Beata , Bielewski Marek , Streli Christina , Wobrauschek Peter 
Published: August 2004

AbstractThe aim of this work was to study the deterioration of various kinds of sandstone due to acid rain and SO2 gas. The samples were taken from three quarries in Poland and one sample was from a tomb about 100 years old. To elucidate the mechanism of stone deterioration, simple experiments were performed. The sandstone samples were immersed for several weeks in SO2 aqueous solution of pH ≈ 4. Similar experiments were performed using SO2 aqueous solution of pH ≈ 1.5. The concentrations of Ca, Mg and Fe leached from the sandstone samples were measured with TXRF. An additional experiment was carried out with the use of radioactive 35SO2. The samples were exposed to both 35SO2 aqueous solution and to 35SO2 gas. The autoradiograms obtained from the sample cross‐sections indicated that sulfur penetrated to the interior parts of sandstone samples, especially from SO2 gas. Copyright © 2004 John Wiley & Sons, Ltd.
Inelastic and elastic scattering differential cross‐sections of 59.5 keV photons for Cu and Zn targets
Authors: Şimşek Ö. , Ertuǧrul M. , Budak G. , Karabulut A. 
Published: August 2004

AbstractDifferential cross‐sections for incoherent and coherent scattering of 59.54 keV photons were measured for Cu and Zn targets at scattering angles of 40–135° in a reflection geometry setup with a graded shielding arrangement. The ratio of these cross‐sections, which can be determined with higher precision than absolute values, is given. A method was used to determine differential incoherent and coherent scattering cross‐sections of elements. This method is based on simultaneous measurement of fluorescence radiation and scattered radiation, thus avoiding problems with measuring source strength and source‐to‐detector solid angle. The measurements were performed using a point source of Am‐241 radioisotope and an Si(Li) detector. The experimental results, which complement earlier results, were compared with the theories of incoherent scattering function and form factor. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative thickness determination using x‐ray fluorescence: application to multiple layers
Authors: Nygård K. , Hämäläinen K. , Manninen S. , Jalas P. , Ruottinen J.‐P. 
Published: August 2004

AbstractThe fundamental parameter method using x‐ray fluorescence was applied to the quantitative determination of single and multiple layer thicknesses using a compact experimental setup. Focused white‐beam radiation was obtained from a high‐voltage Mo x‐ray tube and the fluorescence spectra were acquired using a Peltier‐cooled Si solid‐state detector. The results show that in the case of single layers the accuracy of the thicknesses obtained is very good whereas for multiple layer structures the agreement is poorer, especially for the thinnest layers. This indicates a possible drawback of the standard‐free thickness determination scheme based on fundamental parameters for complex samples. Copyright © 2004 John Wiley & Sons, Ltd.
Sclerosing Epithelioid Fibrosarcomas Involving the Neuraxis: Report of Three Cases
Authors: Bilsky Mark H. , Schefler Amy C. , Sandberg David I. , Dunkel Ira J. , Rosenblum Marc K. 
Published: September 2004

Abstract

OBJECTIVE AND IMPORTANCE
Sclerosing epithelioid fibrosarcoma (SEF) is a rare mesenchymal neoplasm composed of rounded, vimentin-immunoreactive tumor cells disposed in nests and cords within a hyalinized collagenous matrix. Most examples arise in the deep skeletal muscles of adults. The cases recorded to date have been characterized by protracted clinical evolutions with a tendency for stubborn local recurrence, followed by late metastasis. Accordingly, SEF has been regarded as a low-grade sarcoma. A single instance of brain and vertebral metastasis has been described. We report three examples of SEF distinguished by primary involvement of the neuraxis at initial presentation.

CLINICAL PRESENTATION
Two tumors had intracranial, calvarial and extracalvarial, soft-tissue components, whereas the third tumor manifested as a paraspinal mass with extension into the T12–L1 neural foramen and invasion of the T12 nerve root.

INTERVENTION
All three affected patients experienced local recurrence and distant metastasis after resection of the primary site. These complications appeared early in the disease course in two cases. In no case was there a response to adjuvant chemotherapy or radiotherapy.

CONCLUSION
Our experience indicates that SEFs arising along the neuraxis may demonstrate unexpectedly aggressive clinical behavior, compared with those arising in the more typical location of deep skeletal muscles.
Modified Malis Bayonet Forceps Aids Application of the Cyberonics Vagus Nerve Stimulator Electrode: Technical Note
Authors: Carey Michael E. , Kutz Scott 
Published: September 2004

Abstract

OBJECTIVE
To notify neurosurgeons about a modified bayonet forceps that aids application of the vagus nerve stimulating electrode.

METHODS
The manufacturer (Codman & Shurtleff, Inc., Raynham, MA) extended the tips of an upward-angled Malis bayonet forceps from 2 mm to 6 mm.

RESULTS
The modified bayonet tips, when placed under the vagus nerve, extend well beyond the edge of the usual vagus nerve to easily accept the electrode lead.

CONCLUSION
The modified bayonet forceps and depicted wrapping sequence shorten electrode wrapping time.
Olfactory Ensheathing Cells: Bridging the Gap in Spinal Cord Injury
Authors: Bartolomei Juan C. , Greer Charles A. 
Published: September 2004

AbstractSPINAL CORD INJURY (SCI) continues to be an insidious and challenging problem for scientists and clinicians. Recent neuroscientific advances have changed the pessimistic notion that axons are not capable of significant extension after transection. The challenges of recovering from SCI have been broadly divided into four areas: 1) cell survival; 2) axon regeneration (growth); 3) correct targeting by growing axons; and 4) establishment of correct and functional synaptic appositions. After acute SCI, there seems to be a therapeutic window of opportunity within which the devastating consequences of the secondary injury can be ameliorated. This is supported by several observations in which apoptotic glial cells have been identified up to 1 week after acute SCI. Moreover, autopsy studies have identified anatomically preserved but unmyelinated axons that could potentially subserve normal physiological properties. These observations suggest that therapeutic strategies after SCI can be directed into two broad modalities: 1) prevention or amelioration of the secondary injury, and 2) restorative or regenerative interventions. Intraspinal transplants have been used after SCI as a means for restoring the severed neuraxis. Fetal cell transplants and, more recently, progenitor cells have been used to restore intraspinal circuitry or to serve as relay for damaged axons. In an attempt to remyelinate anatomically preserved but physiologically disrupted axons, newer therapeutic interventions have incorporated the transplantation of myelinating cells, such as Schwann cells, oligodendrocytes, and olfactory ensheathing cells. Of these cells, the olfactory ensheathing cells have become a more favorable candidate for extensive remyelination and axonal regeneration. Olfactory ensheathing cells are found along the full length of the olfactory nerve, from the basal lamina of the epithelium to the olfactory bulb, crossing the peripheral nervous system-central nervous system junction. In vitro, these cells promote robust axonal growth, in part through cell adhesion molecules and possibly by secretion of neurotrophic growth factors that support axonal elongation and extension. In animal models of SCI, transplantation of ensheathing cells supports axonal remyelination and extensive migration throughout the length of the spinal cord. Although the specific properties of these cells that govern enhanced axon regeneration remain to be elucidated, it seems certain that they will contribute to the establishment of new horizons in SCI research.
Multiple Interstitial Substances Measured by Microdialysis in Patients with Subarachnoid Hemorrhage
Authors: Staub Frank , Graf Rudolf , Gabel Paula , Köchling Matthias , Klug Norfrid , Heiss Wolf-Dieter 
Published: September 2004

Abstract

OBJECTIVE
Intracerebral microdialysis is a tool to monitor metabolic disturbances in the brains of patients with severe head injuries or subarachnoid hemorrhage (SAH). In the search for putative indicators of primary and secondary brain damage, we measured multiple metabolites in the dialysates of patients with SAH, to elucidate their significance for the outcomes of the patients as well as their temporal profiles of liberation after the insult.

METHODS
Microdialysis probes were placed, with a ventriculostomy catheter for drainage of cerebrospinal fluid, into a frontal lobe of 10 patients with aneurysmal SAH, for 4.6 ± 0.5 days. Amino acids, metabolites of glycolysis, purines, catecholamines, and nitric oxide oxidation byproducts were measured by high-performance liquid chromatography. Spearman's correlation coefficient and Student's t test were used to compare the levels of the metabolites with the outcomes of the patients, as assessed using the Glasgow Outcome Scale, 3 months after the ictus.

RESULTS
For patients with unfavorable outcomes (Glasgow Outcome Scale scores of 1–3), which were primarily associated with the development of large infarctions, dialysate levels of excitatory amino acids increased up to 30-fold, those of lactate up to 10-fold, and those of nitrite up to 5-fold, compared with normal levels observed for patients with favorable outcomes (Glasgow Outcome Scale scores of 4 or 5). When average peak concentrations in the dialysates of patients with favorable and unfavorable outcomes were compared, significantly higher levels of excitatory amino acids, taurine, lactate, and nitrite, but not of purines and catecholamines, were observed for those with poor outcomes (P &lt; 0.05). With respect to the temporal profiles of the average metabolite concentrations, the significantly increased levels of amino acids observed for patients with poor outcomes followed a biphasic course, with maximal concentrations on the first and second days or the seventh day after the insult (P &lt; 0.01).

CONCLUSION
These data confirm the usefulness of excitatory amino acids and lactate as major parameters for neurochemical monitoring for patients threatened by acute cerebral disorders. Other substances, such as taurine and nitrite, were also demonstrated to be potentially predictive. Release of these substances into the extracellular fluid of the brain might be particularly relevant for the development of secondary brain damage after SAH, e.g., infarction or brain swelling.
Signal peptide prediction based on analysis of experimentally verified cleavage sites
Authors: Zhang Zemin , Henzel William J. 
Published: September 2004

AbstractA number of computational tools are available for detecting signal peptides, but their abilities to locate the signal peptide cleavage sites vary significantly and are often less than satisfactory. We characterized a set of 270 secreted recombinant human proteins by automated Edman analysis and used the verified cleavage sites to evaluate the success rate of a number of computational prediction programs. An examination of the frequency of amino acid in the N‐terminal region of the data set showed a preference of proline and glutamine but a bias against tyrosine. The data set was compared to the SWISS‐PROT database and revealed a high percentage of discrepancies with cleavage site annotations that were computationally generated. The best program for predicting signal sequences was found to be SignalP 2.0‐NN with an accuracy of 78.1% for cleavage site recognition. The new data set can be utilized for refining prediction algorithms, and we have built an improved version of profile hidden Markov model for signal peptides based on the new data.
Sedimentation velocity studies of the high–molecular weight aggregates of the HIV gp41 ectodomain
Authors: Jacobs Amy , Hartman Kari , Laue Thomas , Caffrey Michael 
Published: September 2004

AbstractAccumulation of the HIV envelope protein gp41 is observed in the brain tissues of patients suffering from HIV‐associated dementia. Previously, we have shown by electron microscopy that the extracellular domain of SIV gp41, which is analogous to that of HIV, forms high–molecular weight aggregates in vitro, and we have postulated that such high–molecular weight aggregates are responsible for neurological damage in a manner similar to protein deposition diseases such as Alzheimer's and the prion diseases. In this manuscript, we have characterized the self‐association of the HIV gp41 ectodomain by sedimentation velocity. We show that discreet species of the gp41 high–molecular weight aggregates are present. The maximum population occurs at 20 S, which corresponds to ∼5 trimers of gp41, suggesting that five trimers are required for nucleation of the high–molecular weight aggregates. The concentration dependence of the gp41 self‐association indicates that it occurs by mass action. The temperature dependence of gp41 self‐association suggests that it is driven by entropy, indicating that intermolecular hydrophobic interactions between trimers of gp41 are driving the association.
Computed tomography evaluation of cavitary necrosis in complicated childhood pneumonia
Authors: Koşucu P , Ahmetoğlu A , Çay A , İmamoğlu M , Özdemir O , Dinç H , Sarihan H , Gümele HR 
Published: September 2004

SUMMARYThe purpose of the present study was to retrospectively investigate the chest radiograph (CR) and CT findings of childhood pneumonia complicated by cavitary necrosis, and to evaluate the role of CT in decision‐making for surgical intervention. Chest CT was performed in 51 patients presenting with persistent or progressive pneumonia, respiratory distress and sepsis despite 7−10 days of appropriate antibiotic treatment and closed tube drainage. Chest radiograph and CT findings were retrospectively evaluated in 23 patients (45%) with cavitary necrosis. Chest radiographs showed consolidation in 19 of 23 patients, cavitation in five patients, parapneumonic effusions in 17 patients and air−fluid levels in the pleural space in one patient. The CT scans demonstrated consolidation and cavitary necrosis in all patients. There were parapneumonic effusions in all patients with concomitant loculated collections in six patients. Twenty‐two of 23 patients had pleural thickening. In seven patients there were air−fluid levels in the pleural space. In five of these patients, CT scans demonstrated bronchopleural fistulae. On the basis of the CT and clinical findings, 11 patients underwent surgical intervention. Computed tomography is superior to CR for demonstrating cavitary necrosis complicating pneumonia, and other parenchymal and pleural complications. It also has a crucial decision‐making role for surgery.
Bladder pheochromocytoma encountered on sonography
Authors: Çeliktaş M , Okur N , Aikimbaev KS , Binokay F , Sert M , Akgül E 
Published: September 2004

SummaryPheochromocytomas of the bladder are rare neoplasms, constituting <0.06% of all vesical tumours. Common presenting features of this tumour include episodes of sweating, hypertension, haematuria and postmicturition syncope. We describe a case of bladder pheochromocytoma in a 66‐year‐old man whose only symptom of macroscopic haematuria was initially assessed with ultrasonography. Clinical presentation highlights the need for a high index of suspicion during sonographic evaluation of bladder neoplasms because such tumours might present without symptoms of adrenergic excess.
Transition planning and the needs of young people and their carers: the alumni project
Authors: Smart Melanie 
Published: September 2004

Melanie Smart is a research associate at Sunfield School, Worcestershire, and a trainee clinical psychologist. In this article, she reports the results of a small‐scale survey which looked at the views of 17 parents whose children with severe and/or complex learning difficulties had made the transition from a residential special school to an adult placement. Pa rents were asked their retrospective views on the transition planning process; their own involvement; and how the adult placement met the needs of their children.Melanie Smart's findings indicate that the majority of parents were very much involved in the planning process, although they reported struggling to get consistency of approach and basic information. The young people themselves were found to be marginalised in the planning process, with very few being involved in any decision making. Most parents were happy with the eventual placement, but those who had concerns were still pushing for basic services and care. Of those who had suffered placement breakdowns, the major factor was lack of consistency of approach and failure to use prior information about the child.This survey shows that parents and their learning disabled children experience difficulties in the transition process. There seems to be a distinct lack of person‐centred planning, particularly with this user group, by both child and adult services. Parents are vital to this type of planning approach, particularly when the young people themselves cannot voice their needs or advocate their own rights to quality service provision. Melanie Smart argues that parents need access to better quality information and reassurance that their children will receive the services they deserve as young adults. The various agencies, she asserts, need to work together to ensure that the transition process is effective.