bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein Sequences and Cellular Factors Required for Polar Localization of a Histidine Kinase in
Caulobacter crescentus
Authors: Sciochetti Stephen A. , Lane Todd , Ohta Noriko , Newton Austin 
Published: October 2002

ABSTRACT

The
Caulobacter crescentus
sensor kinase DivJ is required for an early cell division step and localizes at the base of the newly formed stalk during the G1-to-S-phase transition when the protein is synthesized. To identify sequences within DivJ that are required for polar localization, we examined the ability of mutagenized DivJ sequences to direct localization of the green fluorescent protein. The effects of overlapping C-terminal deletions of DivJ established that the N-terminal 326 residues, which do not contain the kinase catalytic domain, are sufficient for polar localization of the fusion protein. Internal deletions mapped a shorter sequence between residues 251 and 312 of the cytoplasmic linker that are required for efficient localization of this sensor kinase. PleC kinase mutants, which are blocked in the swarmer-to-stalked-cell transition and form flagellated, nonmotile cells, also fail to localize DivJ. To dissect the cellular factors involved in establishing subcellular polarity, we have examined DivJ localization in a
pleC
mutant suppressed by the
sokA301
allele of
ctrA
and in a
pleD
mutant, both of which display a supermotile, stalkless phenotype. The observation that these Mot
+
strains localize DivJ to a single cell pole indicate that localization may be closely coupled to the gain of motility and that normal stalk formation is not required. We have also observed, however, that filamentous
parC
mutant cells, which are defective in DNA segregation and the completion of cell separation, are motile and still fail to localize DivJ to the new cell pole. These results suggest that formation of new sites for DivJ localization depends on events associated with the completion of cell separation as well as the gain of motility. Analysis of PleC and PleD mutants also provides insights into the function of the His-Asp proteins in cell cycle regulation. Thus, the ability of the
sokA301
allele of
ctrA
to bypass the nonmotile phenotype of the
pleC
null mutation provides evidence that the PleC kinase controls cell motility by initiating a signal transduction pathway regulating activity of the global response regulator CtrA. Analysis of the
pleD
mutant cell cycle demonstrates that disruption of the swarmer-to-stalked-cell developmental sequence does not affect the asymmetric organization of the
Caulobacter
cell cycle.
Modified Walsh‐Hadamard sequences for DS CDMA wireless systems
Authors: Wysocki B. J. , Wysocki T. A. 
Published: October 2002

AbstractWe propose a simple but efficient method for modifying Walsh–Hadamard sequences to achieve correlation properties suited for asynchronous DS CDMA applications. The proposed method can be used to minimize the mean square value of aperiodic cross‐correlation or the mean square value of aperiodic autocorrelation, the maximum value of aperiodic cross‐correlation functions, merit factor or other properties of the sequence set. The important feature of the method is that it modifies correlation properties of the sequence set, while preserving their orthogonality for the perfect synchronization. The proposed method can be applied to obtain bipolar, quadri‐phase, or general polyphase sequences. Copyright © 2002 John Wiley & Sons, Ltd.
Carbon black filled conducting polymers and polymer blends
Authors: Huang Jan‐Chan 
Published: October 2002

AbstractThe objective of this article was to review the use of carbon black (CB) as a conductive filler in polymers and polymer blends. Important properties of CB related to its use in conducting polymers are discussed. The effects of polymer structure, molecular weight, surface tension, and processing conditions on electrical resistivity and physical properties of composites are discussed. Several percolation models applicable to CB/polymer blends are reviewed. Emphasis is placed on recent trends using polymer blends as the matrix to obtain conducting composites at a lower CB loading. A criterion for the distribution of CB in polymer blends is discussed. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 299–313, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10025
An attempt at engineering the bulk properties of blends of a bitumen with polymers
Authors: Fawcett Allan H. , McNally Tony , McNally Gerry 
Published: October 2002

AbstractWe have taken blends of a bitumen with three homopolymers that produce systems softer than the bitumen, and to each have added small quantities of different semicrystalline polyolefins. The intention is to discover whether these will form an extensive network system within a blend with a low Tg in which crystallites create the cross‐links, as may happen with the isotactic polypropylene present in some atactic polypropylene systems. Such thermoplastic cross‐links might provide a useful feature for certain uses, such as in built‐up roofing membranes. These were found only within one blend based upon the polybutadiene, in two blends based upon chlorinated polyethylene, but in none based on the Lycra®, whose blends with LLDPEs and the HDPE flowed below the crystal melting temperature. The E′′ plots indicate the presence of many loss processes within the blends at low temperatures: the tan δ plots show other processes active up to 200°C within the soft matter. The behavior we discovered suggests that the properties of binary polymer blends are not associated solely with the components, but that, when the material is stiff or after heating, certain polymer—bitumen interactions may also be significant, and are sensitive to slight differences of structure between LLDPEs, even when present at the 3.4% level. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 275–286, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10032
Work environment effects on labor productivity: An intervention study in a storage building
Authors: Niemelä Raimo , Rautio Sari , Hannula Mika , Reijula Kari 
Published: October 2002

AbstractBackgroundAlthough increased attention has been focused on the relationship between occupational health and productivity, solid scientific data on this topic are sparse. The purpose of the present case study was to assess the relationship between productivity and work environment in a storage building.Materials and MethodsThe study was implemented as an intervention consisting of the renovation of a harbor storage facility. The study design consisted of a single group of employees working in the storage hall. The physical and chemical factors, perceived environment, and labor productivity were measured before and after the renovation.ResultsAs a result of the renovation, thermal conditions, air quality, and lighting conditions improved notably. In addition, the employees' subjective evaluations showed the significant decrease in dissatisfaction ratings. The direct measure for the labor productivity, expressed as zinc tons/work‐hour (tn) increased about 9% after the renovation.DiscussionWe conclude that increased productivity is most likely related to the combined effect of the improved work environment, i.e., better thermal climate, reduced contaminant concentrations, and better lighting conditions. Am. J. Ind. Med. 42:328–335, 2002. © 2002 Wiley‐Liss, Inc.
Hematological changes among Chinese workers with a broad range of benzene exposures
Authors: Qu Qingshan , Shore Roy , Li Guilan , Jin Ximei , Chi Chen Lung , Cohen Beverly , Melikian Assieh A. , Eastmond David , Rappaport Stephen M. , Yin Songnian , Li Heyi , Waidyanatha Suramya , Li Yuying , Mu Ruidong , Zhang Xiaoling , Li Keqi 
Published: October 2002

AbstractBackgroundDepression of peripheral blood cells is a well‐known indicator of benzene hematotoxicity. Previous studies of its effects on specific types of blood cells have yielded inconsistent results. We examine hematological findings and their possible relations with exposure markers validated in a recent biomarker project conducted in Tianjin, China.MethodsPersonal benzene exposures were sampled with 3‐M organic vapor monitors, and analyzed by gas chromatography. The peripheral blood cells were counted by a cell counter. The WBC differential was manually counted on a total of 900 cells by a US commercial laboratory.ResultsA total of 130 exposed workers and 51 age‐ and gender‐matched unexposed subjects were recruited in this study. Benzene exposure levels monitored on the day of biological sample collection for exposed workers ranged from 0.06 to 122 ppm. Their 4‐week average and cumulative benzene exposure levels were 0.08–54.5 ppm and 6.1–623.2 ppm‐years, respectively. Significant decreases of red blood cells (RBC), white blood cells (WBC), and neutrophils were observed and correlated with both personal benzene exposures and levels of urinary metabolites (S‐phenylmercapuric acid and t,t‐muconic acid) and albumin adducts of benzene oxide and 1,4‐benzeoquinone.ConclusionsThe depressions in RBC, WBC, and neutrophils observed in this study are not only exposure dependent, but also significantly different in the lowest exposed group (at or below 0.25 ppm) compared with unexposed subjects. The results of the present study appear to suggest that lymphocytes may not be more sensitive to chronic benzene exposure than neutrophils. Am. J. Ind. Med. 42:275–285, 2002. © 2002 Wiley‐Liss, Inc.
Alagille syndrome inherited from a phenotypically normal mother with a mosaic 20p microdeletion
Authors: Laufer‐Cahana Ayala , Krantz Ian D. , Bason Lynn D. , Lu Feng‐Min , Piccoli David A. , Spinner Nancy B. 
Published: October 2002

AbstractWe report an 18‐month‐old girl with Alagille syndrome, caused by a submicroscopic deletion of chromosome 20p, including the Jagged1 (JAG1) gene. FISH using a BAC probe containing JAG1 identified the deletion. Chromosomes were normal at the 550 band level. The deletion was inherited from her phenotypically normal mother who was found to have the deletion in 9/20 cells studied from peripheral blood. This is the first report of a JAG1 deletion inherited from an apparently unaffected mosaic parent. © 2002 Wiley‐Liss, Inc.
De novo complete trisomy 5p: Clinical and neuroradiological findings
Authors: Grosso Salvatore , Cioni Maddalena , Garibaldi Gianluca , Pucci Lucia , Galluzzi Paolo , Canapicchi Raffaello , Morgese Guido , Balestri Paolo 
Published: October 2002

AbstractPartial or complete duplication of 5p is a rare chromosomal abnormality in which genotype‐phenotype correlation studies are hampered by other commonly associated chromosomal abnormalities. We report on a new patient in whom a complete de novo trisomy 5p in all metaphases represented the only chromosomal aberration. The present case further contributes to delineate the typical clinical picture of the trisomy 5p syndrome. Long‐term clinical follow‐up demonstrated low levels of secretory immunoglobulin A (IgA) on several occasions and likely related to the patient's recurrent respiratory infections (RRIs), a main clinical feature of the trisomy 5p syndrome. An extensive neuroradiological study detected a progressive triventricular hydrocephalus during the fist year of life with subsequent stabilization. Neuronal migration disorders were also present and probably account for the drug‐resistant epilepsy presented by the patient. © 2002 Wiley‐Liss, Inc.
From fins to limbs to fins: Limb evolution in fossil marine reptiles
Authors: Caldwell Michael W. 
Published: October 2002

AbstractLimb osteology and ontogenetic patterns of limb ossification are reviewed for extinct lineages of aquatically adapted diapsid reptiles. Phylogenies including these fossil taxa show that paddle‐like limbs were independently derived, and that the varied limb morphologies were produced by evolutionary modifications to different aspects of the limb skeleton. Ancient marine reptiles modify the limb by reducing the relative size of the epipodials, modifying the perichondral and periosteal surface of elements distal to the propodials, and evolving extremes of hyperphalangy and hyperdactyly. Developmental genetic models illuminate gene systems that may have controlled limb evolution in these animals. © 2002 Wiley‐Liss, Inc.
Impact of industrialization: Comparative study of child health in four sites from medieval and postmedieval England (A.D. 850–1859)
Authors: Lewis Mary E. 
Published: October 2002

AbstractThe morbidity and mortality profiles of 831 non‐adult skeletons from four contrasting sites in medieval and postmedieval England were compared to assess whether urbanization and later industrialization, had a detrimental effect on the health of the inhabitants. Failure in the population's ability to adapt to these environments should be evident in the higher rates of mortality, retarded growth, higher levels of stress, and a greater prevalence of metabolic and infectious disease in the urban groups. Non‐adult skeletons were examined from Raunds Furnells in Northamptonshire, from St. Helen‐on‐the‐Walls and Wharram Percy in Yorkshire, and from Christ Church Spitalfields in London. Results showed that a greater number of older children were being buried at the later medieval sites and that the skeletal growth profiles of the medieval urban and rural children did not differ significantly. A comparison of the growth profiles of St. Helen‐on‐the‐Walls (urban) and Spitalfields (industrial) showed that the Spitalfields children were up to 3 cm shorter than their later medieval counterparts. At Spitalfields, cribra orbitalia and enamel hypoplasias occurred during the first 6 months of life, and 54% of the non‐adults had evidence of metabolic disease. It is argued that differences in the morbidity and mortality of non‐adults from urban and rural environments did exist in the past, but that it was industrialization that had the greatest impact on child health. Environmental conditions, urban employment, socioeconomic status, and changes in weaning ages and infant feeding practices contributed to differences in health in rural, urban, and industrial environments. Am J Phys Anthropol 119:211–223, 2002. © 2002 Wiley‐Liss, Inc.
Assessment of different treatment failure criteria in a cohort of relapsing–remitting multiple sclerosis patients treated with interferon β: Implications for clinical trials
Authors: Río Jordi , Nos Carlos , Tintoré Mar , Borrás Cecilia , Galán Ingrid , Comabella Manuel , Montalban Xavier 
Published: October 2002

AbstractClinical trials with interferons in relapsing–remitting multiple sclerosis have shown a modest effect on disability using fixed definitions of treatment failure to measure disease progression. However, in the course of the disease, treatment failure may be influenced by interrater variability and frequent remissions. Thus, the purpose of this study was to assess the clinical usefulness of different treatment failure criteria in a cohort of relapsing–remitting multiple sclerosis patients treated with interferon β. We studied 252 patients with a follow‐up of more than 2 years. We used four different criteria of treatment failure with increasing stringency (1 Expanded Disability Status Scale [EDSS] point increase confirmed at 3 months, 1 EDSS point increase confirmed at 6 months, 1.5 EDSS points increase confirmed at 3 months, and 1.5 EDSS points increase confirmed at 6 months). We divided treatment failure into permanent treatment failure and transient treatment failure. We considered permanent treatment failure when treatment failure was confirmed on the last two scheduled visits and transient treatment failure when treatment failure was not confirmed on these visits at different time points (9, 12, 18, and 24 months). We calculated the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the different criteria of treatment failure to identify patients who achieved a high degree of disability after 4 years of follow‐up. Regardless of the stringency of treatment failure definitions, a variable proportion of patients with treatment failure had transient treatment failure depending on the criterion applied. Patients with transient treatment failure had a significantly lower EDSS at entry compared with those with permanent treatment failure or no treatment failure. The number of relapses in patients with transient treatment failure did not differ from that of patients with permanent treatment failure. The criterion of confirmed 1 EDSS point increase at 6 months showed the best sensitivity (76.5%), with satisfactory specificity (89%). Our study shows that a large proportion of patients treated with interferon experience transient treatment failure that may affect outcome interpretation in clinical trials. Using a more strict criterion, as extending time to confirmation of EDSS deterioration, and longer follow‐up may reduce this proportion of patients with transient treatment failure and improve the validity of the results attained in clinical trials.
Imaging the metabolic footprint of Glut1 deficiency on the brain
Authors: Pascual Juan M. , van Heertum Ronald L. , Wang Dong , Engelstad Kristin , De Vivo Darryl C. 
Published: October 2002

AbstractCerebral 18F‐fluorodeoxyglucose positron emission tomography in 14 patients with microcephaly, developmental delay, seizures, and mutations of the glucose transporter Glut1 (Glut1 deficiency syndrome) showed distinct abnormalities. Within a global context of diminished cortical uptake, more severe hypometabolism was found in the mesial temporal regions and thalami, accentuating a relative signal increase in the basal ganglia. In contrast, the structure of the brain appeared preserved in patients additionally investigated by magnetic resonance imaging. This metabolic footprint was relatively constant in all patients regardless of age, seizure history, or therapies and therefore constitutes a radiological signature of the disease. The full expression of the signature in the youngest patient (aged 19 months) indicates that the state of haploinsufficiency caused by Glut1 mutation leaves a permanent footprint on the nervous system from its earlier postnatal stages of development. The potential benefit of prompt diagnosis, aided by 18F‐fluorodeoxyglucose positron emission tomography, and early initiation of available therapies is underscored by our results.
Involvement of lysosomes in the pathogenesis of CAG repeat diseases
Authors: Yamada Mitsunori , Tsuji Shoji , Takahashi Hitoshi 
Published: October 2002

AbstractIn CAG repeat diseases, affected neurons possess many cytoplasmic granules immunopositive for expanded polyglutamine stretches. Electron microscopic immunohistochemistry showed that the granules corresponded to lysosomes of primitive type. The results suggest that, in addition to the ubiquitin/proteasome pathway, mutant proteins with expanded polyglutamine stretches are involved in the lysosomal pathway for protein degradation and that this processing mechanism may serve as a target for a new therapeutic approach to CAG repeat diseases.
Photodegradation of thermoplastic elastomeric rubber–polyethylene blends
Authors: Bhowmick Anil K , Heslop J. , White J. R. 
Published: October 2002

AbstractThe photodegradation of a new family of thermoplastic elastomers, based on blends of natural rubber and polyethylene, was studied with laboratory ultraviolet exposures in the unstrained state and under tensile strain (25 and 50%). Strained exposure caused reduction of the strain to failure in subsequent tensile tests. The blends were more resistant to degradation than the natural rubber homopolymer. The introduction of crosslinks (at a low concentration so that the thermoplastic nature of the blends was retained) changed the resistance to photo‐oxidation. Two different crosslinking systems were used. When dicumyl peroxide was used as the crosslinking agent, the resistance to degradation was reduced, whereas the compound containing a sulfur curing system showed improved resistance to photodegradation. Photo‐oxidation rather than ozone degradation was found to be the major cause of breakdown, even with samples held in tension. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2393–2402, 2002
Rheological and morphological properties of high‐density polyethylene and poly(ethylene–octene) blends
Authors: Guimarães Maria José O. C. , Coutinho Fernanda M. B. , Rocha Marisa C. G. , Farah Marcelo , Bretas Rosário E. S. 
Published: October 2002

AbstractThe rheological and morphological properties of blends based on high‐density polyethylene (HDPE) and a commercial ethylene–octene copolymer (EOC) produced by metallocene technology were investigated. The rheological properties were evaluated in steady and dynamic shear experiments at 190°C in shear rates ranging from 90 s−1 to 1500 s−1 and frequency range between 10−1 rad/s and 102 rad/s, respectively. These blends presented a high level of homogeneity in the molten state and rheological behavior was generally intermediate to those of the pure components. Scanning electron microscopy (SEM) showed that the blends exhibit dispersed morphologies with EOC domains distributed homogeneously and with particle size inferior to 2 μm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2240–2246, 2002
Effects of reprocessing on the structure and mechanical properties of poly(trimethylene terephthalate)
Authors: Ramiro J. , Eguiazábal J. I. , Nazábal J. 
Published: October 2002

AbstractThe effects of reprocessing by extrusion for up to four cycles on the structure and mechanical properties of poly(trimethylene terephthalate) (PTT) were studied. Reprocessing did not change the chemical structure of the polymer but led to both yellowing and molecular weight reduction. Young's modulus and the yield stress of PTT remained constant or decreased with successive extrusion cycles, probably because of the observed slight specific volume increase. The continuous reduction in the break properties due to reprocessing was smaller than that found in similar polyesters and was attributed to the molecular weight reduction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2775–2780, 2002
Preparation and properties of polyamide 6/polypropylene–vermiculite nanocomposite/polyamide 6 alloys
Authors: Tjong S. C. , Meng Y. Z. , Xu Y. 
Published: October 2002

AbstractPolypropylene–vermiculite nanocomposites can be achieved by simple melt mixing of maleic anhydride‐modified vermiculite with polypropylene. Maleic anhydride acts either as a compatibilizer for the polymeric matrix or as a swelling agent for the silicate. Compatibilized blends are injection molded directly from polyamide 6 and polypropylene–vermiculite nanocomposites. Scanning electron microscopy observation reveals that a two‐phase structure consisting of polypropylene–vermiculite nanocomposite and polyamide 6 is formed in the blends. The absence of vermiculite reflections in the X‐ray powder diffraction patterns indicates that the polypropylene–vermiculite phase exhibits nanocomposite characteristics. Tensile test shows that the tensile modulus of the polymer alloy tends to increase with increasing polypropylene–vermiculite nanocomposite content. The tensile strength of composite containing 8 wt % vermiculite is higher than that of pure polyamide 6. Finally, the thermal properties of the nanocomposites are determined by dynamic mechanical analysis, differential scanning calorimetry, and thermogravimetric measurements. The effects of maleic anhydride addition on the formation of polypropylene–vermiculite nanocomposite reinforcement and on the mechanical properties of composites are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2330–2337, 2002