bluuebunny/crossref_metadata_2025_split huggingface dataset:
New measurement of 239+240Pu concentration in the IAEA reference materials SOIL-6 and IAEA-375
Authors: Chang Zhiyuan , Zhao Min , Jiang Songsheng , Li Jinghnai , Zhao Yonggang , Li Auli , Diao Lijun 
Published: April 2004

Summary
Under an IAEA project for upgrading of the reference materials, a new measurement of 239+240Pu in the IAEA reference materials, SOIL-6 and IAEA-375, were performed. The extraction chromatography and a low background α-spectrometer were used for separation of plutonium and determination of 239+240Pu activity in the SOIL-6 and IAEA-375 samples. Homogeneity of SOIL-6 and IAEA-375 materials was checked by both F- and t-tests. The result showed that both materials could be considered to be sufficiently homogenous for weight of 30-50g. Activity concentration (C
A) of 239+240Pu in the SOIL-6 and IAEA-375 materials were determined to be (0.96±10.030) and (0.285±0.017)Bqkg-1 at 95% confidence level, respectively, at June 2002. The both present values of 239+240Pu C
A agree with the IAEA recommended in 95% confidence interval, but the both present values have high precision. Since the recommended values for SOIL-6 and IAEA-375 materials were issued about 20 and 10 years ago and error range of their recommended values were large, our obtained results might be useful in upgrading of the recommended values.
Physiological and Metabolic Interpretation of Diffusion‐Weighted Imaging Changes During Cerebral Ischemia
Authors: Hilger Thomas , Hoehn Mathias 
Published: April 2004

AbstractDiffusion‐weighted imaging (DWI) has become one of the most important imaging modalities for the characterization of acute stroke. In this review article the connection between DWI and independent non‐MR parameters is evaluated, thereby providing the background for the physiological and metabolic interpretation of DWI changes. The pathophysiological consequences reflected by DWI changes are determined by the duration and intensity of an ischemic event. Reversible changes in water diffusion of tissue are triggered at a cerebral blood flow decrease to approximately 35–40 mL/100g*min. More severe hemodynamic disturbances (<20 mL/100g*min) obviously result in irreversible tissue damage. Furthermore, a distinct relative decrease of the apparent diffusion coefficient (ADC) to 90% of control indicates tissue acidosis, and it has been shown that, under certain conditions, the ADC reflects the current energy state of the brain, as validated by the distribution of ATP. A close correlation between the depletion of ATP and an ADC decrease to 77% of control was found for the acute phase of both permanent and transient cerebral ischemia. The correlation of diffusion changes with final tissue damage revealed that ADC can reliably predict histopathological damage during the early acute phase of cerebral ischemia and after transient recovery. However, in the intermediate phase, while histology showed further cellular degeneration, ADC obviously does not reflect the tissue status. Depending on the individual situation, a moderate ADC decrease to ca. 70–80% of control must not necessarily result in irreversible tissue damage, whereas more severe decline to ca. 60% of control presumably transforms to necrosis.
Polymerization of α‐Olefins Using Benzamidinate Zirconium Complexes Supported on Mesoporous Silica Materials
Authors: Ray Biswajit , Volkis Victoria , Lisovskii Anatoly , Eisen Moris S. 
Published: April 2004

AbstractThe polymerization of ethylene and propylene were studied using an anchored dimethyl benzamidinate zirconium complex. As supports, mesoporous silicas MCM‐41 and HMS were utilized. These inorganic materials were reacted with methylalumoxane to serve as the cocatalyst and to avoid the deactivation of the active cationic complex. The reaction of the octahedral benzamidinate zirconium complex with the supported cocatalysts results in the formation of active catalytic systems for the polymerization of olefins. The polymer properties were found to depend on the nature of the supports. The activity of the heterogeneous catalysts and the polymer characteristics were compared with those obtained with the homogeneous catalyst.
Synthetic flux‐promoting polyether models: Cation flux dependence on polyoxyethylene chain length
Authors: Espínola Carmen G. , Delgado Mercedes , Martín Julio D. 
Published: April 2004

AbstractA novel class of cyclic polyoxyethylene derivatives incorporating a polybenzylated oxane system has been prepared via ruthenium‐catalyzed ring‐closing metathesis. These polyethers were incorporated into phospholipid vesicles and shown to facilitate transmembrane sodium transport. Maximum efficiency in sodium flux occurred when polyoxygenated chain lengths were similar to the leaflet thickness in bilayers. It is proposed that polyethers dimerize in order to function. The association constants of these polyethers with alkali metal cations and methyl ammonium ion have been evaluated using Cram's picrate extraction method.
Biomedical Applications of Diffusion‐Weighted NMR Techniques
Authors: Cohen Jack S. 
Published: April 2004

AbstractMRI is a well‐established tool in clinical diagnosis, but it lacks the specificity that would allow clear distinctions between many disease conditions. That is mainly because it is a spatial tool that lacks functional information. There are several other NMR techniques that could be used to provide functional information and thus improve the specificity of MR diagnostics. One of these is the use of diffusion‐weighted (DW) MRI, which provides information about the diffusion of water in tissue. Preliminary animal and clinical results indicate that changes of the diffusion properties in tumors might provide early prediction of response or non‐reponse to therapy. Another useful adjunct to MRI is the application of NMR spectroscopy (or MRS), which provides spectroscopic information mainly on the metabolic components of the tissue. However, notwithstanding many years of research, proton MRS has not so far proved a useful adjunct to MRI for the physician. This is mainly because of (a) the presence of the huge solvent water peak and (b) the mixture of both intra‐ and extracellular metabolic components in the tissue. A further extension of MRS would be the use of DWMRS, which is the application of the DW technique to the spectroscopic components of tissue other than water. Using DWMRS we are able to observe only the intracellular metabolic components and their changes due to drug treatment. In this article we will explore the potential of these DW methods as applied to (a) perfused cells, (b) brain tumors in mice, and (c) human brain tumors.
Strategies for stereocontrol at C1 or C2 in syntheses of α‐glucosaminides
Authors: Fraser‐Reid Bert , Anilkumar G. , Nair Latha G. , Olsson Lars , Martin Mercedes Garcia , Daniels Jacquitta K. 
Published: April 2004

AbstractThe C1 and C2 stereocenters of α‐glucosaminides can be prepared by establishing the stereocenters in either order. For the former, a C2‐azido glucosyl donor is prepared first, and the restraining effect of a 4,6‐O‐benzylidene ring is used to induce α‐coupling. For the latter, the C1 linkage is prepared first by use of an n‐pentenyl‐manno‐1,2‐orthoester donor which ensures (a) clean α‐coupling and (b) a convenient C2‐ester. The C2‐ester is replaced with a triflate leaving group, and nucleophilic displacement is effected by use of a hypervalent silicon azide.
Self‐consistent hybrid approach for simulating electron transfer reactions in condensed phases
Authors: Wang Haobin , Thoss Michael 
Published: April 2004

AbstractThe recently proposed self‐consistent hybrid method is presented as a numerical tool for simulating quantum dynamics in complex systems. This method is based on an iterative convergence procedure for a dynamical hybrid approach. In this approach the overall system is partitioned into a core and a reservoir. The former is treated via a numerically exact quantum mechanical method, and the latter is treated via a more approximate method. Self‐consistent iterations are then carried out, with the number of core degrees of freedom and other variational parameters increased systematically to achieve numerical convergence for the overall quantum dynamics. The details of treating the core and the reservoir, as well as the convergence procedure, are discussed for several examples of electron transfer reactions in condensed phases. It is shown that the self‐consistent hybrid method provides an accurate and practical way of simulating quantum dissipative dynamics in a wide range of physical regimes.
On the relative rate of hydrolysis of a series of ketals and their proton affinities
Authors: Li Shigui , Dory Yves L. , Deslongchamps Pierre 
Published: April 2004

AbstractThe relative rates of hydrolysis of a series of cyclic and acyclic ketals was studied. Their reactivity toward acid hydrolysis is explained by considering the ease of protonation and the cleavage of the C—O bond. The experimental work and the theoretical calculations of the proton affinities of the ketals suggest that the rate‐limiting step of hydrolysis of ketals is a concerted protonation and cleavage of the C—O bond. The relative proton affinity is considered to be a direct consequence of the ease of proper lone pair orbital alignment on the oxygen atoms of the various ketals.
Two‐way interactions between ocean biota and climate mediated by biogeochemical cycles
Authors: Gildor Hezi , Follows Michael J. 
Published: April 2004

AbstractSome of the two‐way interactions between ocean biota and climate are mediated by biogeochemical cycles that link the different components of the climate system. As suggested by proxy records extracted from ice and ocean cores, by recent measurements, and by numerical models, such two‐way interactions were likely major players in past climate variability on glacial—interglacial timescales, and may act to amplify or moderate an anthropogenically induced climate change in the near future. At present, our lack of understanding of these interactions hampers our ability to anticipate the consequences of possible anthropogenic climate change. In this article, we highlight some of the possible feedbacks between ocean biota and climate, reviewing some key biogeochemical processes and discussing mechanisms of two‐way interactions. We also outline the need and strategies for continuing research aimed at advancing our understanding of these feedbacks and discuss their significance.
Studies on Pseudomonas aeruginosa cd1 nitrite reductase: The association and dissociation reactions of the d1‐heme
Authors: Wilson Emma K. , Bellelli Andrea , Arese Marzia , Cutruzzolà Francesca , Brunori Maurizio , Aoyagi Katsuhiro , Smith Kevin M. 
Published: April 2004

AbstractThe dissociation and association reactions of the d1‐heme, the prosthetic group characteristic of cd1 nitrite reductases (NiRs), have been investigated to assess the stability of the native enzyme. At pH 5.0 and 37 °C, the rate constant for the dissociation of the ferric d1‐heme from native NiR purified from Pseudomonas aeruginosa is 4.7 ± 1.4 × 10−4 s−1. However, when the d1‐heme is in the ferrous state no dissociation is observed, consistent with the shortening and strengthening of the proximal bond upon reduction of the iron. Recombinant wild‐type protein and two single point mutants (Y10N and Y10F), which are expressed as semi‐apo proteins and were reconstituted with synthetic d1‐heme, display the same slow dissociation rate as the native enzyme. Therefore the stability of the d1‐heme bound in the crevice provided by the eight‐bladed ß propeller domain is not altered by the act of reconstitution or by these two point mutations. The association reaction between the ferric d1‐heme and semi‐apo NiR is second‐order and governed by an apparent rate constant of 3.3 × 106 M−1 s−1 at neutral pH and 25 °C. Interestingly, the combination rate constant is an order of magnitude slower than that reported for iron protoporphyrin IX and apomyoglobins or apohemoglobins. This difference appears to be a property of the d1‐heme and not of the protein since association rate constants of CO‐protoheme‐Fe(II) and dicyanoprotoheme‐Fe(III) with semi‐apo NiR are 5 × 107 M−1 s−1 and 6 × 107 M−1 s−1, respectively. These results are discussed with reference to the structure of the d1‐heme binding site, as inferred from the known 3D structure of P. aeruginosa NiR.
Adaptive control for a radio‐controlled helicopter in a vertical flying stand
Authors: Dzul Alejandro , Lozano Rogelio , Castillo Pedro 
Published: April 2004

AbstractIn this paper, we focus on the design and implementation of a controller for a two degree‐of‐freedom system. This system is composed of a small‐scale helicopter which is mounted on a vertical platform. The model is based on Lagrangian formulation and the controller is obtained by classical pole‐placement techniques for the yaw dynamics and adaptive pole‐placement for the altitude dynamics. Experimental results show the performance of such a controller. Copyright © 2004 John Wiley & Sons, Ltd.
Paucity of TEL‐AML 1 translocation, by multiplex RT‐PCR, in B‐lineage acute lymphoblastic leukemia (ALL) in Indian patients
Authors: Sazawal S. , Bhatia K. , Gutierrez M.I. , Saxena R. , Arya L.S. , Bhargava M. 
Published: April 2004

AbstractA total of 69 patients of B lineage ALL, 35 children (32 males, 3 females) and 34 young adults (27 males, 7 females) were studied by multiplex RT‐PCR to determine the relative frequency of t(9;22), t(12;21), t(1;19), and t(4;11,). Translocation (9;22) was seen in 1/35 (2.8%) and t(1;19) in 2/35 (5.7%) children. None of the children showed t(12;21) and t(4;11) translocations. In young adults, t(9;22) and t(1;19) were seen in 5/34 (14.7%) and 2/34 (5.8%) patients, respectively. None of the latter showed t(12;21) or t(4;11) translocations. Thus, there appears to be a significant under representation of the fusion transcripts for TEL‐AML, a good prognostic marker, in this study, unlike in the West, where it is seen in 35% of children with ALL. This, together with the generally increased leukemic burden seen in Indian patients, may explain in part, the poor treatment outcome reported. Am. J. Hematol. 76:80–82, 2004. © 2004 Wiley‐Liss, Inc.
Second malignant neoplasms in childhood acute lymphoblastic leukemia: Primitive neuroectodermal tumor of the chest wall with germline p53 mutation as a second malignant neoplasm
Authors: Suarez Carlos R. , Bertolone Salvatore J. , Raj Ashok B. , Coventry Susan 
Published: April 2004

AbstractAbout 80% of children treated for acute lymphoblastic leukemia (ALL) will be long‐term survivors. Second malignant neoplasm (SMNs) are a devastating sequelae observed on these children, with an estimated cumulative risk of 2–3.3% fifteen years after diagnosis. Primitive neuroectodermal tumor of bone (PNET) is rarely observed as a SMN following treatment of childhood ALL. The authors described the occurrence of a chest wall PNET of the bone at the site of a central line placement associated with both germ‐line and tumor cell p53 mutation in a 8‐year‐old boy 1 year after completing therapy for standard risk ALL. A review of the literature of 25,051 children treated for ALL discovered 230 SMNs (0.99%), and only one case of PNET of the bone was noted among this group. The occurrence of a SMN in children treated for ALL is a rare event. Such an occurrence, in particular the development of an unusual SMN, should be evaluated for a germline p53 mutation. Am. J. Hematol. 76:52–56, 2004. © 2004 Wiley‐Liss, Inc.
R147W mutation of PROC gene is common in venous thrombotic patients in Taiwanese Chinese
Authors: Tsay Woei , Shen Ming‐Ching 
Published: April 2004

AbstractWe analyzed the genetic defects of 21 unrelated patients with venous thrombosis in whom hereditary protein C deficiency was diagnosed. Eleven mutations were detected in 18 families, while no mutation was detectable in the other three families. Among these mutations, a common genetic mutation of protein C (PROC) gene recurred in 43% (nine propositi from these 21 families). This C6152T mutation at exon 7 resulted in a missense mutation, Arg147Trp (R147W). Each propositus or family carrier had another specific polymorphism T66C at exon 2, which did not change the proline at position (−21). The haplotype analysis strongly suggested a founder effect. The first thrombotic attack was significantly younger in patients with multiple genetic defects or combined with other risk factors than those without precipitating factors. We further studied the prevalence rate of R147W mutations in normal populations through PCR amplification and dot hybridization. Three different cohorts got similar results. The prevalence rate of R147W in health controls is 0.85% [95% confidence interval (CI) 0.35–1.35]. Analysis of plasma protein C levels of all patients or carriers suggested that R147W was a type II deficiency. The odds ratio of thrombosis of R147W is 5.1 (95% CI 1.7–14.8). Taken together, R147W mutation is a significant thrombotic risk factor and is the most common defect of PROC gene in Taiwanese patients with protein C deficiency. This finding is important for screening thrombophilic families in Chinese populations. Am. J. Hematol. 76:8–13, 2004. © 2004 Wiley‐Liss, Inc.
Allogeneic hematopoietic stem cell transplantation for seven children with X‐linked hyper‐IgM syndrome: A single center experience
Authors: Tomizawa Daisuke , Imai Kohsuke , Ito Sukeyuki , Kajiwara Michiko , Minegishi Yoshiyuki , Nagasawa Masayuki , Morio Tomohiro , Nonoyama Shigeaki , Mizutani Shuki 
Published: April 2004

AbstractX‐linked hyper‐IgM syndrome (XHIM), or hyper‐IgM syndrome type 1 (HIGM1), is a rare primary immunodeficiency disorder susceptible to recurrent bacterial infection and opportunistic infection such as Pneumocystis carinii and Cryptosporidium parvum. The long‐term outcome is quite poor, and allogeneic hematopoietic stem cell transplantation (HSCT) offers the only cure. Seven patients with XHIM, from age 3 to 19 years (mean 11.3 years), underwent allogeneic HSCT in our institution. Details of pre‐ and post‐transplantation data and transplantation procedure were analyzed retrospectively. The donors were HLA‐identical siblings for three patients and HLA‐identical unrelated donors for four patients. All but one received conventional conditioning regimen consisting of busulfan and cyclophosphamide and prophylaxis for graft‐versus‐host disease (GVHD) consisting of cyclosporine and methotrexate. Five out of seven patients are alive and well with normal CD40L expression, and four of these five are free of intravenous immunoglobulin supplementation. The two patients who died had prolonged episodes of severe and recurrent infections and organ damage. We conclude that conventional allogeneic HSCT from HLA matched related or unrelated donors is curative and feasible for XHIM patients, if performed before significant infections and organ damage occur. For the high‐risk patients, an alternative approach including nonmyeloablative HSCT may be more feasible. Am. J. Hematol. 76:33–39, 2004. © 2004 Wiley‐Liss, Inc.
Cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) gene polymorphism and susceptibility to non‐Hodgkin's lymphoma
Authors: Monne Maria , Piras Giovanna , Palmas Angelo , Arru Luigi , Murineddu Marco , Latte Giancarlo , Noli Annalisa , Gabbas Attilio 
Published: April 2004

AbstractThe CTLA‐4 molecule plays an important role in immune regulation by downregulating activation of T cells. Polymorphisms in the CTLA‐4 gene have been shown to be associated to a number of autoimmune diseases including blood disorders. In this study, the intragenic polymorphisms of the CTLA‐4 gene at position −318*C/T, +49*A/G, and the dinucleotide (AT)n repeat polymorphism in exon 3 were analyzed in patients with non‐Hodgkin's lymphoma. Genotype and haplotype analysis showed that the exon 1+49*AA genotype was over‐represented among patients with NHL (P = 0.002), whereas no difference was observed for the −318*C/T promoter and the (AT)n polymorphisms (P > 0.05). The data obtained indicate that the CTLA‐4+49A/G polymorphism may have a role in genetic susceptibility to NHL. Am. J. Hematol. 76:14–18, 2004. © 2004 Wiley‐Liss, Inc.
Thalidomide in POEMS syndrome: Case report
Authors: Sinisalo Marjatta , Hietaharju Aki , Sauranen Jukka , Wirta Ole 
Published: April 2004

AbstractWe report a patient with incapacitating POEMS syndrome characterized by serum monoclonal protein, polyneuropathy, organomegaly, endocrinopathy, mesangiocapillary glomerulonephritis, massive ascites formation, and pulmonary hypertension. A dramatic improvement in the clinical condition occurred after administration of thalidomide, a drug with known anti‐angiogenetic, anti‐proliferative, and anti‐cytokine properties. Am. J. Hematol. 76:66–68, 2004. © 2004 Wiley‐Liss, Inc.
Neutrophilic panniculitis with myelodysplastic syndromes presenting as pustulosis: Case report and review of the literature
Authors: Chen Hsiang‐Cheng , Kao Woei‐Yau , Chang Deh‐Ming , Gao Hong‐Wei , Lai Wei‐Yu , Lai Jenn‐Haung 
Published: April 2004

AbstractNeutrophilic panniculitis associated with myelodysplastic syndromes is rare. We report a 59‐year‐old patient who initially was diagnosed with myelodysplastic syndrome (MDS) and developed a sudden onset of widespread pustulosis and erythematous indurated papules. Examination of skin biopsies of a papule lesion showed dense neutrophilic infiltration limited to the subcutaneous tissue. The pustules and papules disappeared completely after treatment with systemic corticosteroids. To our knowledge, only one patient was identified by MEDLINE search of the English‐language literature. Am. J. Hematol. 76:61–65, 2004. © 2004 Wiley‐Liss, Inc.
Newly recognized syndrome of metaphyseal undermodeling, spondylar dysplasia, and overgrowth: Report of two adolescents and a child
Authors: Nishimura Gen , Hasegawa Tomonobu , Kinoshita Eiichi , Tanaka Yoko , Kurosawa Kenzi , Yoshimoto Masaaki 
Published: April 2004

AbstractWe report on a previously undescribed syndrome characterized by generalized skeletal alterations and overgrowth in three unrelated individuals: a boy who died at age 16 years, a 16‐year‐old girl, and a 15‐month‐old boy. The skeletal changes included bony overgrowth of the skull base, spondylar dysplasia, and undermodeling of the tubular bones. Bone age was accelerated in early childhood. Overgrowth, which was independent of GH–IGF axis, was of prenatal onset in the two boys, but postnatal in the girl. In the two adolescents, growth rate did not decline with age, and high‐dose estrogen therapy failed to induce physeal fusion. Their adolescent height reached +4∼+7 SD of the mean. Delayed puberty in the girl and cryptorchidism and hypospadias in the younger boy raised the possibility that hypogonadism is a syndromic constituent. Molecular analysis of IGF2, GPC3, and FGFR3 in the older boy yielded no abnormalities. © 2004 Wiley‐Liss, Inc.