bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aging of the human neuromuscular system
Authors: Vandervoort Anthony A. 
Published: September 2002

AbstractLoss of cells from the motor system occurs during the normal aging process, leading to reduction in the complement of motor neurons and muscle fibers. The latter age‐related decrease in muscle mass has been termed “sarcopenia” and is often combined with the detrimental effects of a sedentary lifestyle in older adults, leading to a significant reduction in reserve capacity of the neuromuscular system, which is the primary subject of this review. Clear evidence of this aging effect is seen when voluntary or stimulated muscle strength is compared across the adult lifespan, with a steady decline of ∼1–2% per year occurring after the sixth decade. Interestingly, when compared with isometric contractions, the effect of aging is more pronounced for concentric movements and less for eccentric movements (i.e., muscle shortening versus lengthening). This phenomenon appears to be linked to the stiffer muscle structures and prolonged myosin crossbridge cycles of aged muscles. It is encouraging that the capability of physiological adaptations in the motor pathways remains into very old age — when an appropriate exercise stimulus is given — and long‐term prevention strategies are advocated to avoid excessive physical impairments and activity restrictions in this age group. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 17–25, 2002
Near optimization of stochastic dynamic systems by decomposition and aggregation
Authors: Sethi S.P. , Zhang Q. 
Published: September 2002

AbstractThe paper is concerned with the reduction of a class of stochastic optimal control problems to simpler problems by using decomposition and aggregation. Decomposition is shown to provide a good approximation when the system dynamics involve nearly decomposable matrices or variables with strong and weak interactions. Aggregation provides a good approximation if each decomposed matrix has one or more dominant eigenvalues. It is shown how one can construct nearly optimal controls for the given system from the optimal solutions of the simpler reduced problems. The results extend the corresponding results obtained (Sethi and Zhang, Journal of optimization theory and applications 1998; 99:1–22) in a deterministic environment. The results hold a significant promise in dealing with large dynamic stochastic macroeconomic problems. Copyright © 2001 John Wiley & Sons, Ltd.
Triisobutylaluminum as cocatalyst for zirconocenes. I. Sterically opened zirconocene/triisobutylaluminum/perfluorophenylborate as highly effective ternary catalytic system for synthesis of low molecular weight polyethylenes
Authors: Panin A. N. , Sukhova T. A. , Bravaya N. M. 
Published: September 2002

AbstractEthylene polymerizations with catalytic systems Me2SiCp*NtBuZrX2 (1) [Cp* = C5(CH3)4; X = Cl (1Cl), Me (1Me)], triisobutylaluminum (TIBA), perfluorophenylborate CatB(C6F5)4 [Cat = CPh3 (3), Me2NHPh (4)], or Me2SiCp2ZrX2 [X = Cl (2Cl), Me (2Me)]/TIBA/3 (4) were performed within a wide range of ethylene pressures of different Al/Zr ratios, and Zr/B = 1. Catalytic systems 1Cl(2Cl)/TIBA/3 led to the formation of very high linear molecular weight polyethylene (PE) of Mη ∼2,000,000 with low activity. The replacement of both chlorine ligands in the precatalyst for the methyl ones led to the formation of active species producing low molecular weight PE with high activity. Chain transfer to ethylene was shown to be the main reaction controlling PE chain propagation: kp/ktr ∼20–30 for 1Me/TIBA/3 and kp/ktr ∼350–500 for 2Me/TIBA/3. It was suggested that TIBA was present in the active center first in the form of a neutral heterobimetallic Zr–Al bridged complex followed by the formation of a partially polarized Zr–Al(Cl)R2 (R = iBu) or an unreactive Zr–AlR3 cationic complex by abstraction of the alkyl ligand under the action of borate. It was concluded that AlR3 from the latter cationic complex may be easily reversibly replaced under the specific coordination of ethylene or accumulated α‐olefin, giving rise to highly labile and sterically accessible cationic species. Experiments on ethylene polymerization with the catalytic systems 1Cl(1Me)/TIBA/3/Ph2NH, 1Cl(1Me)/TIBA/4, 2Cl(2Me)/TIBA/3/Ph2NH, and 2Cl(2Me)/TIBA/4 were performed to confirm the suggestion. Catalytic systems derived from dichloride complexes in the presence of a σ‐donor substrate also produced low molecular weight PEs with molecular weight characteristics similar to those of products obtained with the dimethylated precatalysts. The specific feature of active species derived from 2Me complexes to isomerize coordinated α‐olefin into trans‐vinylene polymer chains was also revealed. The catalytic behavior of the ternary catalytic system based on 2Me relative to 2Me or 2Cl precatalysts activated with polymethylaluminoxane at different Al/Zr ratios was compared. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1901–1914, 2001
Mechanical properties of emulsion polymer blends
Authors: Robeson Lloyd. M. , Berner Robert. A. 
Published: September 2002

AbstractPolymer blend technology has been one of the most investigated areas in polymer science in the past 3 decades. The one area of polymer blends that has been virtually ignored involves simple emulsion blends, although several articles have recently appeared that address film formation and mechanical characteristics. In this study, we investigated the mechanical property behavior of emulsion blends composed of low/high‐glass‐transition‐temperature polymers (where low and high mean below and above the test temperature, respectively). The emulsions chosen for this study had similar particle sizes, and the mixtures were rheologically stable. Two conditions were chosen, a binary combination of polymers that were thermodynamically immiscible and another system that was thermodynamically miscible. The mechanical property results over the entire composition range were compared with the predictions of the equivalent box model (EBM) with the universal parameters predicted by percolation theory. An array of randomly mixed and equal‐size particles of differing moduli was expected to show excellent agreement with theory, and the emulsion blends provided an excellent experimental basis for testing the theory. For the immiscible blend, the EBM prediction for the modulus showed excellent agreement with experimental results. With tensile strength, the agreement between the modulus and theory was good if the yield strength for the higher glass‐transition‐temperature polymer was employed in comparison with the actual tensile strength. The phase inversion point (where both phases were equally continuous) was at a 0.50 volume fraction of each component (based on an analysis employing Kerner's equation), just as expected for a random mixture of equal‐size particles. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1093–1106, 2001
Molecular orbital interpretation of thymine/graphite nc‐AFM images
Authors: Komiyama Masaharu , Uchihashi Takayuki , Sugawara Yasuhiro , Morita Seizo 
Published: September 2002

AbstractRecent non‐contact atomic force microscopy (nc‐AFM) images of a deoxyribonucleic acid (DNA) base thymine (2,4‐dioxy‐5‐methylpyrimidine) vacuum‐deposited on a highly oriented pyrolytic graphite (HOPG) surface are interpreted by means of theoretical adsorption simulations, and the molecular geometry and the energetics of the adsorption system are estimated. The lowest‐energy dimer configuration was found to be the one in which the respective hydrogen on N1 and the oxygen on C6 of two thymine molecules hydrogen bond to each other. A surface unit cell structure was reproduced. Adsorption energy for the thymine pair on HOPG is rather small, amounting to only ∼1 kcal mol−1, with small variations depending on the molecular orientation with respect to the substrate surface. The possibility of having a mirrored adsorption configuration in adjacent domains also is suggested. Copyright © 2001 John Wiley & Sons, Ltd.
Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes
Authors: Ho C. C. , Khew M. C. , Liew Y. F. 
Published: September 2002

AbstractColloidally stable latex blends of natural rubber (NR) and poly(methyl methacrylate) (PMMA) latexes containing up to 50 wt.% PMMA can be prepared by mixing commercial NR ammoniated latex concentrate and monodisperse PMMA latex dispersion. The clarity and tackiness of the films obtained depend on the PMMA content; films become opaque and non‐tacky at >30 wt.% PMMA content. The morphology of these films shows asymmetric distribution of the PMMA particles across the thickness of the film. There is preferential enrichment of PMMA particles at both the air/polymer and glass/polymer interfaces and a predominating NR interior. More PMMA particles are accumulated preferentially at the glass/polymer interface than at the air/polymer interface. The accumulation of the PMMA particles at the interface is strongly dependent on the size and concentration of the PMMA particles. The formation of these asymmetric latex films is explained in terms of the surface energetics, compatibility, Tg and density of the polymers, stability of the component latex, surface chemistry and particle size of the latex particles used. Copyright © 2001 John Wiley & Sons, Ltd.
Interfacial microstructure evolution in aluminium matrix composites reinforced with unoxidized and oxidized SiC particles
Authors: Shi Zhongliang , Ochiai Shijiro , Gu Mingyuan , Hojo Masaki , Lee Jae‐chul 
Published: September 2002

AbstractInterfacial microstructure evolution of Al matrix composites with non‐oxidized and oxidized SiC particles as reinforcement was investigated using x‐ray diffraction, field emission scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM). Hexagonal platelet‐shaped Al4C3 and Si are the two major interfacial reaction products in the non‐oxidized SiC‐particle‐reinforced Al matrix composites (SiCp/Al). In addition, the eutectic θ‐CuAl2 and Si phases precipitate at the SiCp/matrix interface during the last solidification stage. Observation of the interfacial reaction between the oxidized SiC particles and Al alloy containing Mg shows that the SiO2 layer has good bonding with both SiC and Al matrix and that nanoparticles of MgO have formed initially. The MgO particles will change into octahedral MgAl2O4 crystals when there is a low Mg content in the matrix (≤2 wt.%) and will remain as MgO when there is a high Mg content (≥4 wt.%). Copyright © 2001 John Wiley & Sons, Ltd.
From cofactor to enzymes. The molecular evolution of pyridoxal‐5′‐phosphate‐dependent enzymes
Authors: Christen Philipp , Mehta Perdeep K. 
Published: September 2002

AbstractThe pyridoxal‐5′‐phosphate (vitamin B6)‐dependent enzymes that act on amino acid substrates have multiple evolutionary origins. Thus, the common mechanistic features of B6 enzymes are not accidental historical traits but reflect evolutionary or chemical necessities. The B6 enzymes belong to four independent evolutionary lineages of paralogous proteins, of which the α family (with aspartate aminotransferase as the prototype enzyme) is by far the largest and most diverse. The considerably smaller β family (tryptophan synthase β as the prototype enzyme) is structurally and functionally more homogenous. Both the D‐alanine aminotransferase family and the alanine racemase family consist of only a few enzymes. The primordial pyridoxal‐5′‐phosphate‐dependent protein catalysts apparently first diverged into reaction‐specific protoenzymes, which then diverged further by specializing for substrate specificity. Aminotransferases as well as amino acid decarboxylases are found in two different evolutionary lineages, providing examples of convergent enzyme evolution. The functional specialization of most B6 enzymes seems to have already occurred in the universal ancestor cell before the divergence of eukaryotes, archebacteria, and eubacteria 1500 million years ago. Pyridoxal‐5′‐phosphate must have emerged very early in biological evolution; conceivably, metal ions and organic cofactors were the first biological catalysts. To simulate particular steps of molecular evolution, both the substrate and reaction specificity of existent B6 enzymes were changed by substitution of active‐site residues, and monoclonal pyridoxal‐5′‐phosphate‐dependent catalytic antibodies were produced with selection criteria that might have been operative in the evolution of protein‐assisted pyridoxal catalysis. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:436–447, 2001
Prophylaxis of hepatitis B reactivation using lamivudine in a patient receiving rituximab
Authors: Hamaki Tamae , Kami Masahiro , Kusumi Eiji , Ueyama Jun‐ichi , Miyakoshi Shigesaburo , Morinaga Shin‐ichi , Mutou Yoshitomo 
Published: September 2002

AbstractA 53‐year‐old man who had a history of fluminant hepatitis caused by precore mutant hepatitis B virus (HBV) was admitted to our hospital for the treatment of relapsed non‐Hodgkin's lymphoma in July 2000. At admission, serum levels of aspartate aminotransferase and alanine aminotransferase were normal, but he tested positive for HBs antigen. The titer was 64‐fold by radioimmunoassay. We initiated lamivudine at a daily dose of 75 mg to prevent HBV proliferation during chemotherapy. By September 2000, he had received six courses of rituximab at 375 mg/m2 and four courses of fludarabine and mitoxantrone. No hepatic damage was observed from the initiation of treatment until March 2001. At present, four months after the completion of chemotherapy, he continues lamivudine, and the titer of HBs antigen is low at 4‐fold. Rituximab is usually associated with mild toxicity, usually limited to infusion periods. The drug is not generally associated with increased incidence of opportunistic infections. However, some case reports have been recently published on severe viral infections following administration of rituximab. These include fluminant hepatitis caused by HBV, pure red cell aplasia due to parvovirus B19 and fatal varicella‐zoster infection. While it remains unknown whether rituximab can be safely administered in patients with chronic HBV infection, this case report suggested that prophylactic administration of lamivudine is beneficial for suppressing reactivation of HBV during chemotherapy including rituximab. Rituximab should be used cautiously for patients with HBV infection, but prophylactic administration of lamivudine may be beneficial for preventing reactivation of HBV. Am. J. Hematol. 68:292–294, 2001. © 2001 Wiley‐Liss, Inc.
Idarubicin, cytarabine, and topotecan in patients with refractory or relapsed acute myelogenous leukemia and high‐risk myelodysplastic syndrome
Authors: Lee Seung Tae , Jang Joon Ho , Suh Hyung Chan , Hahn Jee Sook , Ko Yun Woong , Min Yoo Hong 
Published: September 2002

AbstractIn an effort to develop more effective therapy for patients with refractory or relapsed acute myelogenous leukemia (AML) and high‐risk myelodysplastic syndrome (MDS), we investigated the efficacy of a combination chemotherapy consisting of idarubicin, cytarabine, and topotecan. Twenty‐seven patients were treated: four with primary refractory AML, nine with AML in first relapse, four with AML in second relapse, and 10 with MDS‐RAEB/RAEBT. Patients received as salvage therapy a single course of idarubicin 12 mg/m2 IV bolus on days 1–3, cytarabine 1 g/m2 over two hours q 12 hr on days 1–5, and topotecan 1.25 mg/m2 over 24 hr on days 1–5. Median age was 42 years (range 17–65 years). All patients were evaluable for response: 14 (51.9%) achieved complete remission, 10 with AML (59%) and four with MDS (40%), respectively. Thirteen AML patients (excluding four relapsed after autologous stem cell transplantation) were grouped into four categories to stratify the probability of achieving complete remission (CR): group 1, first CR duration > or = 2 years and receiving first salvage treatment (S1); group 2, first CR duration 1–2 years and receiving S1; group 3, first CR duration 0–1 years and receiving S1; and group 4, first CR duration 0–1 years and receiving S2, S3, or S4 after failing S1. The response rate of each group was as follows: group 1, one of two (50%); group 2, one of one (100%); group 3, four of four (100%); group 4, two of six (33.3%). The median remission duration and survival of patients with AML were six and 12 months, respectively. Median duration of survival in 10 MDS patients was 15 months, and all four MDS patients achieving a CR maintained continuous CR with a median follow‐up of 11 months. Severe myelosuppression was observed in all patients, resulting in fever or documented infections in 89% of patients. Median time to recovery of neutrophils ≥0.5 × 109/l was 22 days (11–34) and for platelets > 20 × 109/l 35 days (11–58). Reversible grade 3–4 toxicities included diarrhea (two patients) and mucositis (seven patients). We conclude that combination chemotherapy with intermediate dose cytarabine, idarubicin, and topotecan has significant antileukemic activity and acceptable toxicity in salvage AML and high‐risk MDS. Am. J. Hematol. 68:237–245, 2001. © 2001 Wiley‐Liss, Inc.
Cytogenetic and molecular characterization of a patient with simultaneous B‐cell chronic lymphocytic leukemia and peripheral T‐cell lymphoma
Authors: Martin‐Subero J. Ignacio , Siebert Reiner , Harder Lana , Gesk Stefan , Schwindt Peter , Bräuninger Andreas , Willenbrock Klaus , Steinemann Doris , Tiemann Markus , Calasanz Maria Jose , Grote Werner , Ludwig Wolf‐Dieter , Hansmann Martin‐Leo , Schlegelberger Brigitte 
Published: September 2002

AbstractA patient is described who developed a peripheral T‐cell lymphoma (PTCL) after a 6‐year history of B‐cell chronic lymphocytic leukemia (B‐CLL). The progression of the T‐cell disease spreading to pleura and skin terminated the course of the disease. A cytogenetic analysis performed six years after the first onset of the B‐CLL showed the presence of two clones, one with trisomy 12 and another with inv(14)(q11q32.1) and trisomy 8. Combined immunophenotyping and fluorescence in situ hybridization demonstrated that only CD19+ cells contained a trisomy 12, whereas CD3+ cells contained a trisomy 8. Analyses of IgH and TCR rearrangements in single micromanipulated B‐ and T‐cells lacked evidence for a clonal relation between B‐CLL and PTCL cells. Based on our findings, we discuss the different hypotheses which might explain the development of simultaneous PTCL and B‐CLL. Am. J. Hematol. 68:276–279, 2001. © 2001 Wiley‐Liss, Inc.
Age variation in blood pressure: Effect of sex and urbanization in a genetically homogeneous caste population of Andhra Pradesh
Authors: Nirmala A. 
Published: September 2002

AbstractAge variation in blood pressure and prevalence of hypertension were studied in relation to sex and urbanization in a caste population of southern Andhra Pradesh living in rural, semi‐urban, and urban locales. There is an increase in mean blood pressure from rural to semi‐urban areas, and a slight but insignificant decline in urban men. Sex differences in mean blood pressure are significant only in the urban and semi‐urban environments. However, the increase in blood pressure with age is sharper in women than in men, and age effects are more perceptible in the urban setting compared to the other two environments. Similarly, age influences SBP more strongly than DBP. The prevalence of hypertension is greater in urban than in rural areas, at older ages (≥45 years), and in men compared to women. Results of multiple logistic regression suggest that urban residence and alcohol consumption are associated with increased risk of hypertension in men. Higher risk for hypertension in women is more significantly associated with older age (≥45) and obesity (BMI >25). The results indicate that blood pressure and hypertension are more strongly correlated with the indices of modernization and associated lifestyle patterns in men than in women. Am. J. Hum. Biol. 13:744–752, 2001. © 2001 Wiley‐Liss, Inc.
ACP1 and human adaptability: Association with past malarial morbidity in the Sardinian population
Authors: Bottini E. , Palmarino R. , Lucarelli P. , Lista F. , Bottini N. 
Published: September 2002

AbstractAcid Phosphatase locus 1 (ACP1) is a polymorphic enzyme controlled by a locus on chromosome 2 with three common codominant alleles: *A, *B, and *C. ACP1 shows two major isoforms, F and S. The ratio of their concentration differs markedly among genotypes. Two functions have been proposed for the enzyme: flavin‐mononucleotide phosphatase and tyrosine phosphatase activity. An association between ACP1 polymorphism and past malarial morbidity in Sardinia and the Po Valley has been described. Genetic polymorphisms could contribute to natural resistance or susceptibility to the disease. On the other hand, malaria pressure may select for genes that increase susceptibility to common diseases of modern civilization. Thus, the association between ACP1 and malaria in Sardinia in the light of recent understanding of the function of ACP1 and the molecular basis of malaria pathophysiology, especially aspects of the structure of band 3 protein (B3P) and the role of cytokines have been revisited. There is a significant negative correlation between ACP1 S isoform concentration, directly related to the ACP1*C allele, and past malarial morbidity in Sardinia. Populations subjected in the past to a heavy malarial burden show, at present, a lower concentration of the S isoform compared to a nearby malaria‐free population, suggesting that genotypes with high S isoform concentration have been subjected to negative selection in a malarial environment. Correlation analysis and analysis of the joint G‐6‐PD/ACP1 distribution suggest that the relationship between past endemic malaria and the S isoform has not been mediated by glucose‐6‐phosphate dehydrogenase (G‐6‐PD) deficiency, thus pointing to a direct effect of malaria on ACP1. Am. J. Hum. Biol. 13:753–760, 2001. © 2001 Wiley‐Liss, Inc.
Craniodental body mass estimators in the dwarf bushbaby (Galagoides)
Authors: Cuozzo Frank P. 
Published: September 2002

AbstractThis study reports data on 17 craniodental body mass estimators in a sample (n = 38) of dwarf galagos (Galagoides). Correlation coefficients (r) range from a high of 0.64 for bizygomatic breadth and body mass to a low of 0.10 for M3 length and body mass. Of the 17 variables studied, 7 exhibit significant (P < 0.05) correlation coefficients, with 5 of the 7 being multitooth (i.e., tooth row) or cranial variables. In contrast to the correlation coefficients of greater than 0.90 (e.g., Martin [1980] Z Morphol Anthropol 71:115–124; Steudel [1981] Int J Primatol 2:81–90; Gingerich et al. [1982] Am J Phys Anthropol 58:81–100; Conroy [1987] Int J Primatol 8:115–137) published for higher taxonomic level analyses (i.e., all‐primate or prosimian) for many of the same variables studied here, the current data indicate weaker relationships when analyzed at the generic level. Possible explanations for the contrast in correlation coefficients between the current and many previous studies include the following: 1) individual variation due to a geographically dispersed sample, 2) individual body mass fluctuations due to seasonal food availability, and 3) individual variation within the sample due to variation in life‐history parameters. Because the overall size range of the individuals in a specific or generic level analysis is smaller than that in an ordinal or subordinal sample, the individual variation normally masked when using species means represents a larger proportion of the total variation in a more limited sample. This may then be a cause of these weaker correlations. Am J Phys Anthropol 115:187–190, 2001. © 2001 Wiley‐Liss, Inc.