bluuebunny/crossref_metadata_2025 huggingface dataset:
Welding problems with thin brass plates and tungsten inert gas pulse welding
Authors: Meran C. , Yuksel M. , Gulsoz A. , Sekercioglu T.
Published: May 2004

Brass materials are widely used as engineering materials in industry because of their high strength, high corrosion resistance, and high electrical and thermal conductivity. They are easily shaped and they possess a pleasant appearance. However, it is difficult to weld brasses. The main problem with these alloys in fusion welding is the evaporation of zinc during the welding process. After welding, the weld metal becomes porous. Moreover, since the amount of zinc in the alloy is reduced due to evaporation, the brass material loses the physical and chemical properties which it normally possesses. Studies on weldability of brass materials are very few. There is very little information concerning the weldability of brass materials in the literature and general definitions are often seen. It is impossible to find studies on experimental investigations of the welding of brass materials apart for a few exceptions. There are virtually no studies to support experimental data about whether welding of brass materials is possible. The purpose of the present study is to determine suitable parameters by investigating the weldability of brass materials, and the difficulties involved. In order to enable low and controlled heat input into the welding bead, TIG pulse welding is used during experimental studies. The physical and chemical properties of welding beads (penetration, tensile strength, Erichsen deep drawing value, chemical composition of internal structure) have been determined and evaluations have been made.
Comparative methodology for the detection and differentiation of circulating microfilariae of Dirofilaria immitis in the dog
Authors: Mylonakis M.E. , Papadopoulos E. , Koutinas A.F. , Paitaki C. , Leontides L.
Published: May 2004

The sensitivities of the Knott's test (four 20-μl sediment aliquots), quantitative buffy coat capillary tube method (QBC tube, 111 μl of whole blood) and direct blood smear (DBS, 20 μl of whole blood) were evaluated for the detection of microfilaraemia in dogs. Undiluted whole blood samples taken from 70 Dirofilaria immitis antigen-positive dogs and 10 serially diluted microfilaraemic blood samples at concentrations of 400, 200, 100, 50, 25 and 12 microfilariae (mff) ml−1 were examined. For filarial speciation, the buffy coat of QBC tubes was mixed with one drop of methylene blue–formalin solution and examined as a direct smear. In 52/70 microfilaraemic blood samples, the number of mff ranged from 12 to 321987 ml−1 (median: 3199 ml−1). The diagnostic sensitivity of the Knott's test, QBC tube method and DBS in undiluted blood samples attained the 100%, 98% and 92.3% levels, respectively. Eighteen dogs tested amicrofilaraemic by all three methods. At concentrations of 400 mff ml−1, a 100% sensitivity was found by all three methods, while at 200 mff ml−1 the Knott's test, QBC tube and DBS were 100%, 100% and 90% sensitive, respectively. The relevant figures at 100 mff ml−1 were 100%, 100% and 80%, at 50 mff ml−1 100%, 100% and 50%, at 25 mff ml−1 100%, 100% and 10% and at 12 mff ml−1 80%, 50% and 10%. At 50 and 25 mff ml−1, the DBS was less sensitive compared to the other two methods, while at 12 mff ml−1, only to the Knott's test. A significant correlation was found between the QBC tube method and Knott's test regarding mff speciation. Therefore, the QBC method may be considered a reliable alternative to the Knott's test for both the detection and speciation of mff in the dog.
Evaluation by the skin prick test of Anisakis simplex antigen purified by affinity chromatography in patients clinically diagnosed with Anisakis sensitization
Authors: Rodero M. , Cuéllar C. , Chivato T. , Jiménez A. , Mateos J.M. , Laguna R.
Published: May 2004

Anisakis simplex crude extracts (CE) (IPI, ASAC and ALK-ABELLÓ), A. simplex larval antigens purified using a column of IgG anti-A. simplex (PAK) or a column of IgG anti-Ascaris suum (PAS), antigen eluted from columns of IgG anti-A. suum (EAS) and an A. suum adult CE were assayed by the skin prick test. Thirty percent of assayed patients showed a negative reaction in the Anisakis skin prick test. Of 70% positives, two patients had a weal greater than that produced by histamine with the A. simplex extract from ABELLÓ and IPI. The A. suum skin prick test was positive in 35% of patients, with a lower reaction than that observed with the A. simplex extract from IPI in 57% of the sera and a higher reaction in 28% of the sera. All patients with positive reactions with the crude extract also showed positive weals with the two purified antigens, PAK and PAS. All patients, except three, with a reaction to A. suum antigen, were positive to the EAS antigen. In five patients the weal size produced by PAS was greater than that observed with PAK, whereas in another six patients the contrary was observed. Only one of these six patients did not react to EAS antigen, coincident with the patient showing only a slight increase (7%) in the weal size induced by PAK vs. PAS. When the EAS antigen was tested on patients positive to both PAK and PAS, six patients presented a weal size of >30% and only three patients who were positive to PAS did not react to the EAS antigen. These three patients were also negative against the A. suum CE. Purification by affinity chromatography eliminates from the PAS antigen the proteins responsible for producing cross-reactions with Ascaris (present in the EAS antigen).
The role of Bithynia tentaculata in the transmission of larval digeneans from a gravel pit in the Lower Thames Valley
Authors: Morley N.J. , Adam M.E. , Lewis J.W.
Published: May 2004

The freshwater snail, Bithynia tentaculata (Gastropoda: Prosobranchia), is frequently found in gravel pits and its role in the transmission of larval digeneans was assessed in one of these unstable water bodies from the Lower Thames Valley (UK) from June 1982 to December 1984. Eight species of cercarial and five species of metacercarial infections were reported from B. tentaculata, with up to 7.7% and 4.7% prevalence of infections, respectively, occurring in the snail, making it the most important host at this site. Seasonal peaks in cercarial infections occurred in late autumn/early winter but little seasonality was apparent in the occurrence of metacercarial infections. The life history characteristics of both hosts and parasites, which can affect intramolluscan digenean dynamics, are discussed.
The Medi-RIVAGE study (Mediterranean Diet, Cardiovascular Risks and Gene Polymorphisms): rationale, recruitment, design, dietary intervention and baseline characteristics of participants
Authors: Vincent S , Gerber M , Bernard MC , Defoort C , Loundou A , Portugal H , Planells R , Juhan-Vague I , Charpiot P , Grolier P , Amiot-Carlin MJ , Vague P , Lairon D
Published: May 2004

Objective:

To report the rationale, recruitment, design, dietary intervention and baseline characteristics of participants in the Medi-RIVAGE study (Mediterranean Diet, Cardiovascular Risks and Gene Polymorphisms).

Design:

A randomised, parallel trial comparing a new nutritional programme with a conventional programme.

Setting:

Centre for Detection and Prevention of Arteriosclerosis, Timone University Hospital, Marseille, France, and collaborating teams.

Subjects:

Two hundred and twelve male and female volunteers with at least one cardiovascular risk factor.

Intervention:

A Mediterranean-type diet characterised mainly by the quality of fatty acids, amount of fish, vegetable foodstuffs and fibre was proposed and compared with a usually prescribed, low-fat/cholesterol diet. Body mass index, fasting lipids and lipoproteins, apolipoproteins, glucose, insulin and homocysteine were the main outcome measures. Gene polymorphisms of interest were determined.

Results:

Characteristics of men in the two arms were comparable with regard to sociodemographic variables, and clinical and biological cardiovascular risk factors. There were few differences between the groups of women (cholesterol-related parameters,P< 0.05). There was no difference between arms in allelic distribution of the gene polymorphisms studied. Saturated fat and protein intakes were high while carbohydrate and fibre intakes were low, but with no difference between arms. Overall, the nutritional markers were comparable in both arms with few exceptions. Correlations between nutritional intakes and plasma nutrient levels ranged from 0.19 (β-carotene) to 0.47 (folate).

Conclusions:

The comparability of the two arms is notable and warrants a low risk of biases. Current diet departs from the traditional Mediterranean one. The assessment of nutritional intake is validated by correlations obtained between dietary intake and relevant biomarkers. This will be important to estimate participant compliance and to analyse intervention data.
Dietary and socio-economic factors associated with overweight and obesity in a southern French population
Authors: Scali J , Siari S , Grosclaude P , Gerber M
Published: May 2004

Objective:

To investigate the socio-economic and dietary factors associated with overweight and obesity, respectively, in southern France.

Design:

Cross-sectional analysis of socio-economic, lifestyle and nutritional characteristics of a representative population sample. A questionnaire elicited information on anthropometric measurements, socio-economic factors, physical activity, tobacco use, and alcohol and food intakes. Non-parametric tests, multiple linear regression models and correspondence factorial analysis (CFA) were used to estimate the association of the various factors with overweight and obesity.

Setting:

French Southwest and Mediterranean areas.

Subjects:

In total, 1169 subjects (578 women and 552 men), aged 30–77 years, were recruited at random.

Results:

Overweight and obesity were associated with age and education in both genders, reproductive factors in women and tobacco use in men. A few dietary factors were identified (high energy intake and low intake of carbohydrates), but all these variables explained little of the variation (18.5% in women and 14.6% in men). The CFA further investigated the association of lifestyle and nutritional factors, giving more weight to nutritional behaviour for overweight men and women. Factors for obesity differed from those for overweight by being different in men and women, possibly related to psychological behaviour, and there were fewer of them, suggesting an insufficient coverage by the usual questionnaires.

Conclusions:

Overweight and obesity appear as two different entities. Energy imbalance induced by various lifestyle factors plays a major role in the development of overweight, whereas obesity represents a more complex entity where psychological and genetic factors that are difficult to assess may be more important. General nutritional guidelines appear more adapted to the prevention of overweight than to that of obesity, and individual counselling to the prevention of obesity.
The impact of high non-starch polysaccharide intake on serum micronutrient concentrations in a cohort of women
Authors: Greenwood Darren C , Cade Janet E , White Kay , Burley Victoria J , Schorah Chris J
Published: May 2004

Objective:

Many public health campaigns encourage increased fibre consumption, but short-term studies suggest that various components of dietary fibre inhibit the absorption of certain micronutrients including carotenoids. These do not take into account long-term adaptation to nutrient intake levels. We aimed to investigate the effect of non-starch polysaccharide (NSP) fibre on plasma micronutrient concentrations in a large free-living population consuming their usual diet.

Design:

Prospective cohort study. Semi-weighed 4-day food diaries were analysed for micronutrient and NSP fibre intakes. Blood samples were taken and analysed for carotenoids, vitamin A, vitamin E, thiamine, riboflavin, vitamin B6, vitamin B12, folic acid, vitamin C and trace metals.

Setting:

Participants in a large national cohort study who lived within 30 miles of Leeds.

Subjects:

Two hundred and eighty-three middle-aged women.

Results:

The association between NSP intake and plasma nutrient concentrations was assessed taking into account nutrient intakes and other dietary and lifestyle factors. Higher levels of NSP were not associated with lower plasma concentrations of the micronutrients measured, even allowing for the higher nutrient levels generally found in high-fibre foods.

Conclusions:

Amongst middle-aged women we have shown that current guidelines for increasing the population's NSP consumption can be safely applied. Such guidelines are unlikely to reduce serum micronutrient concentrations, although other, more vulnerable population groups may benefit from further investigation.
Observation of twinned martensite in weld heat affected zone of Grade 100 low carbon microalloyed steel
Authors: Poorhaydari K. , Patchett B. M , Ivey D. G.
Published: May 2004

The microstructural changes caused by a low nominal heat input of 0.5 kJ mm-1 in the coarse grained heat affected zone (CGHAZ) of Grade 100 microalloyed steel were investigated. Microhardness measurements suggested that the CGHAZ was martensite of maximum theoretical hardness for the carbon content of the steel. The bulk of the CGHAZ was lath martensite containing none of the small and few of the intermediate sized Nb precipitates responsible for strength and grain size control in the steel plate. Twinned martensite was unexpectedly observed in local areas of the CGHAZ. The formation of twins, which are normally seen in steels with a higher level of carbon, is explained by a combination of the rapid heating rates, high peak temperatures, precipitate dissolution and dispersion, and rapid cooling rates.
Bayesian neural network analysis of ferrite number in stainless steel welds
Authors: Vasudevan M. , Murugananth M. , Bhaduri A. K. , Raj B. , Rao K. Prasad
Published: May 2004

Bayesian neural network (BNN) analysis has been used in the present work to develop an accurate model for predicting the ferrite content in stainless steel welds. The analysis reveals the influence of compositional variations on ferrite content for the stainless steel weld metals, and examines the significance of individual elements, in terms of their influence on ferrite content in stainless steel welds, based on the optimised neural network model. This neural network model for ferrite prediction in stainless steel welds has been developed using the database used to generate the WRC-1992 diagram and the first author's laboratory data. The optimised committee model predicts the ferrite number (FN) in stainless steel welds with greater accuracy than the constitution diagrams and the other FN prediction methods. Using this BNN model, the influence of variations of the individual elements on the FN in austenitic stainless steel welds is also determined, and it is found that the change in FN is a non-linear function of the variation in the concentration of the elements. Elements such as Cr, Ni, N, Mo, Si, Ti, and V are found to influence the FN more significantly than the other elements present in stainless steel welds. Manganese is found to have a weaker influence on the FN. A noteworthy observation is that Ti influences the FN more significantly than does Nb, whereas the WRC-1992 diagram considers only the Nb content in calculating the Cr equivalent.
Adaptive control of back bead in V groove welding without backing plate
Authors: Yamane S. , Yamamoto H. , Ishihara T. , Kubota T. , Eguchi K. , Oshima K.
Published: May 2004

The formation of stable back beads in the first layer weld during one side multilayer welding is important to achieve high quality welded metal joints. The authors thus employed the switch back welding method for welding V groove joints without using backing plates. Moreover, in the field work, there is misalignment of both metal plates during set-up. The suitability of the welding conditions for each root gap and the misalignment were verified by observation of the arc, molten pool and external appearance of back beads. Welding conditions, namely, welding current, wire feedrate, weaving width, forward/backward stroke of switch back motion and welding speed, were controlled continuously according to root gap variations. Stable back beads were obtained for root gaps between 4.9 and 2.3 mm and misalignments between 0.1 and 2.8 mm.
Properties and fracture processes of Si3N4/ Si3N4 joints brazed using Cu–Zn–Ti filler alloy
Authors: Zhang J. , Naka M. , Fang H. Y. , Zhou Y.
Published: May 2004

Si3N4 ceramic was jointed to itself using a filler alloy of Cu-Zn-Ti at 1123-1323 K for 0.3-2.7 ks. Ti content in the Cu-Zn-Ti filler alloy was varied from 5 to 20 at.-%. The effect of brazing parameters, such as brazing temperature, holding time and Ti content, on the mechanical properties and facture processes of the Si3N4/Si3N4 joint were investigated. The results indicated that the increased brazing temperature, holding time and Ti content increase the thickness of the interfacial reaction zone in the Si3N4/filler alloy, and the size and amount of the reaction phases in the filler alloy. Their increases lead to increasing shear strength of the joint. The fracture behaviour of the Si3N4/Si3N4 joint greatly depends on the microstructure of the joint. A suitable thick reaction zone with reaction phases yields the high strength of the Si3N4/ Si3N4 joint.
Liquation cracking in partial penetration aluminium welds: Assessing tendencies to liquate, crack and backfill
Authors: Huang C. , Cao G. , Kou S.
Published: May 2004

Aluminium alloys are susceptible to liquation cracking in the partially melted zone (PMZ), where grain boundary liquation occurs during welding. Alloys 2024, 6061 and 7075 were gas-metal arc welded with fillers 1100 and 4043, and liquation cracking near the weld root was examined. Curves of temperature (T) versus solid fraction (fS), based on the Scheil equation for Al-Cu-Mg-Mn-Si-Zn alloys, were calculated for the solidifying PMZ and weld metal at the fusion boundary. Judging from the freezing temperature range and the liquid fraction, these curves suggested that liquation decreases in the order of 7075, 2024 and 6061, consistent with experiments. They also suggested that 1100 increases the weld metal fS, thus promoting liquation cracking (by strengthening the solidifying and contracting weld metal that pulls the PMZ) and discouraging backfilling (by reducing the interdendritic liquid), while 4043 does the opposite except during PMZ terminal solidification in 7075 and 2024. These are consistent with experiments.
Cobalt‐Mediated Cyclooligomerization Reactions of Borylacetylenes
Authors: Goswami Avijit , Maier Claus‐Jürgen , Pritzkow Hans , Siebert Walter
Published: May 2004

Reaction of bis(diethylamino)acetylene (1) with lithium and chlorobis(dimethylamino)borane yields 1‐[bis(dimethylamino)boryl]‐2‐(diethylamino)acetylene (2). Treatment of 1‐aryl‐2‐(trimethylstannyl)acetylenes 3 with chlorobis(diisopropylamino)borane results in the quantitative formation of 1‐aryl‐2‐[bis(diisopropylamino)boryl]acetylene compounds 4. The 1‐aryl‐2‐borylacetylene derivatives 5, 6, and 7 are obtained by the reaction of 3 with the appropriate haloborane, or by reacting 4 with two equivalents of HCl and one equivalent of catechol, dithiocatechol and 2‐hydroxythiophenol. The catalytic cyclotrimerizations of 5a−d with [CpCo(CO)2] or [Co2(CO)8] lead to isomeric mixtures of the triborylbenzene derivatives 8a−d and 8a′−d′, whereas 6a−d and 7a−b undergo cyclotrimerization only with catalytic amount of [Co2(CO)8], to give isomeric mixtures of the triborylbenzene derivatives 12a−d/12a′−d′ and 13a−b/13a′−b′, respectively. The reaction of 2 with a stoichiometric amount of (η5‐cyclopentadienyl)bis(ethene)cobalt leads to (η5‐cyclopentadienyl)(η4‐cyclobutadiene)cobalt complexes 9. The analogous complexes 10 and 11 are obtained by the reactions of 6 and 7 with a stoichiometric amount of (η5‐cyclopentadienyl)dicarbonylcobalt. Treatment of Co2(CO)8 with 5a, 6a, and 7a yields the dicobaltatetrahedranes 14a, 15a and 16a. Compound 15a reacts with two equivalents of diphenylacetylene and 1‐(1,3,2‐benzodioxaborolyl)‐2‐phenylacetylene (5a), to furnish (1,3,2‐benzodithiaborolyl)pentaphenylbenzene (17) and bis(1,3,2‐benzodioxaborolyl)(1,3,2‐benzodithiaborolyl)triphenylbenzene (18), respectively. The new compounds have been characterized by NMR spectroscopy and mass spectrometry, as well as by X‐ray structural analyses for 4a, 5a, 6a, and 10a. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
D5h Cu5H5X: Pentagonal Hydrocopper Cu5H5 Containing Pentacoordinate Planar Nonmetal Centers (X = B, C, N, O)
Authors: Li Si‐Dian , Miao Chang‐Qing , Ren Guang‐Ming
Published: May 2004

Pentacoordinate planar nonmetals (PPNs) centered in perfect pentagonal hydrocopper complexes Cu5H5X (X = B, C, N, O), as determined by density functional theory methods, are presented in this communication. The results obtained in this work complete the hypercoordinate planar carbon series with high symmetries (D4h, D5h, and D6h), and may shed new insight in catalyst chemistry. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tissue‐specific distribution of donor mitochondrial DNA in cloned mice produced by somatic cell nuclear transfer
Authors: Inoue Kimiko , Ogonuki Narumi , Yamamoto Yoshie , Takano Kaoru , Miki Hiromi , Mochida Keiji , Ogura Atsuo
Published: May 2004

Highly diverse results have been reported for mitochondrial DNA (mtDNA) hetero‐plasmy in nuclear‐transferred farm animals. In this study, we cloned genetically defined mice and investigated donor mtDNA inheritance following somatic cell cloning. Polymerase chain reaction (PCR) analysis with primers that were specific for either the recipient oocytes or donor cells revealed that the donor mtDNA coexisted with the recipient mtDNA in the brain, liver, kidney, and tail tissues of 96% (24/25) of the adult clones. When the proportion of donor mtDNA in each tissue was measured by allele‐specific quantitative PCR and subjected to ANOVA analysis, a tissue‐specific mtDNA segregation pattern (P < 0.05) was observed, with the liver containing the highest proportion of donor mtDNA. Therefore, the donor mtDNA was inherited consistently by the cloned offspring, whereas donor mtDNA segregation was not neutral, which is in accordance with previous notions about tissue‐specific nuclear control of mtDNA segregation. genesis 39:79–83, 2004. © 2004 Wiley‐Liss, Inc.
Coat color‐tagged green mouse with EGFP expressed from the RNA polymerase II promoter
Authors: Hsiao Yi‐Chun , Chang Hsiao‐Hui , Tsai Ching‐Yen , Jong Yiin‐Jeng , Horng Long‐Shyan , Lin Shu‐Fen , Tsai Ting‐Fen
Published: May 2004

Laborious molecular genotyping and variegated gene expression are two widely encountered issues for transgenic mouse studies. To facilitate genotyping in the FVB/N albino background and to reduce variegated expression, we successfully generated double‐tagged transgenic mice for direct visual genotyping with the coat color phenotype derived from tyrosinase cDNA driven by the tyrosinase promoter and with simultaneous high enhanced green fluorescent protein (EGFP) expression driven by the promoter of RNA polymerase II large subunit gene. Incorporation of insulator into a transgene construct achieved high efficiency of transgene expression in more than 90% of the founders. EGFP was detected as early as the one‐cell fertilized egg and lasted for the whole embryo development, as well as in all of the adult tissues examined. The coat color‐tagged green mice offer opportunities in applications such as tissue transplantation, lineage tracing, chimera biology, RNA interference, and other transgenic studies. genesis 39:122–129, 2004. © 2004 Wiley‐Liss, Inc.
Differential expression of neuropsin and protease M/neurosin in oligodendrocytes after injury to the spinal cord
Authors: Terayama Ryuji , Bando Yoshio , Takahashi Takayuki , Yoshida Shigetaka
Published: May 2004

Neuropsin and protease M/neurosin are serine proteases expressed by neurons and glial cells, and serve a variety of functions in the central nervous system (CNS). The current study demonstrates changes in the expression of these proteases following hemisection of the mouse spinal cord. Within unlesioned spinal cord, neuropsin mRNA expression was occasionally observed in the gray but not white matter, while the level of protease M/neurosin mRNA was higher in the white matter. After injury to the spinal cord, neuropsin mRNA expression was induced in the white matter in the area immediately adjacent to the lesion, peaking at 4 days post‐injury and disappearing by 14 days. Enhanced expression of protease M/neurosin mRNA was observed throughout the white and gray matter surrounding the lesion, peaking at 4 days and persisting for 14 days. Neuropsin mRNA was expressed predominantly by CNPase‐positive oligodendrocytes. Furthermore, most of these cells were also associated with immunoreactivity for protease M/neurosin protein. Within unlesioned spinal cord, most protease M/neurosin mRNA‐expressing cells were CNPase‐positive oligodendrocytes, and a substantial fraction of these cells also showed immunoreactivity for NG2, a marker for oligodendrocyte progenitors. After injury, protease M/neurosin mRNA expression within NG2‐positive cells was significantly decreased, while the constitutive expression in CNPase‐positive oligodendrocytes appeared to be preserved. These findings suggest that each subpopulation of oligodendrocytes based on the expression of neuropsin and protease M/neurosin has different roles in the response of the spinal cord to injury as well as in normal homeostasis. © 2004 Wiley‐Liss, Inc.
Visual recognition of faces, objects, and words using degraded stimuli: Where and when it occurs
Authors: Pegna Alan J. , Khateb Asaid , Michel Christoph M. , Landis Theodor
Published: May 2004

We studied time course and cerebral localisation of word, object, and face recognition using event‐related potentials (ERPs) and source localisation techniques. To compare activation rates of these three categories, we used degraded images that easily pop out without any change in the physical features of the stimuli, once the meaning is revealed. Comparisons before and after identification show additional periods of activation beginning at 100 msec for faces and at around 200 msec for objects and words. For faces, this activation occurs predominantly in right temporal areas, whereas for objects, the specific time period gives rise to bilateral posterior but right dominant foci. Finally, words show a maximum area of activation in the left temporooccipital area at their specific time period. These results provide unequivocal evidence that when effects of low‐level visual features are circumvented, faces, objects, and words are not only distinct in terms of their anatomic routes, but also in terms of their times of processing. Hum. Brain Mapping 22:300–310, 2004. © 2004 Wiley‐Liss, Inc.
In vitro osteogenic differentiation of marrow stromal cells encapsulated in biodegradable hydrogels
Authors: Temenoff Johnna S. , Park Hansoo , Jabbari Esmaiel , Sheffield Tiffany L. , LeBaron Richard G. , Ambrose Catherine G. , Mikos Antonios G.
Published: May 2004

Novel hydrogel materials based on oligo(poly(ethylene glycol) fumarate) (OPF) crosslinked with a redox radical initiation system were recently developed in our laboratory as injectable cell carriers for orthopedic tissue engineering applications. The effect of OPF hydrogel material properties on in vitro osteogenic differentiation of encapsulated rat marrow stromal cells (MSCs) with and without the presence of osteogenic supplements (dexamethasone) was investigated. Two OPF formulations that resulted in hydrogels with different swelling properties were used to encapsulate rat MSCs (seeding density ∼13 million cells/mL, samples 6 mm diameter × 0.5 mm thick before swelling) and osteogenic differentiation in these constructs over 28 days in vitro was determined via histology and biochemical assays for alkaline phosphatase, osteopontin and calcium. Evidence of MSC differentiation was apparent over the culture period for samples without dexamethasone, but there was large variability in calcium production between constructs using cells of the same source. Differentiation was also seen in samples cultured with osteogenic supplements, but calcium deposition varied depending on the source pool of MSCs. By day 28, osteopontin and calcium results suggested that, in the presence of dexamethasone, OPF hydrogels with greater swelling promoted embedded MSC differentiation over those that swelled less (43.7 ± 16.5 μg calcium/sample and 16.4 ± 2.8 μg calcium/sample, respectively). In histological sections, mineralized areas were apparent in all sample types many microns away from the cells. These experiments indicate that OPF hydrogels are promising materials for use as injectable MSC carriers and that hydrogel swelling properties can influence osteogenic differentiation of encapsulated progenitor cells. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 235–244, 2004
Effect of streptozotocin on the ultrastructure of rat pancreatic islets
Authors: Mythili M. Daisy , Vyas Rashmi , Akila G. , Gunasekaran S.
Published: May 2004

Our objective was to study the effects of three (30, 40, and 50 mg/kg) doses of Streptozotocin (STZ) on fasting plasma glucose level (FPG) and observe its effects at the cellular level in rat pancreas by electron microscopy. FPG was measured in rats before induction of diabetes and then on 3, 7, and 14 days after induction of diabetes with STZ. Keto diastix urine strips were used to check urine glucose and ketone bodies. Two weeks after the induction of diabetes, the rat pancreas was removed and fixed for light and electron microscopic studies. Three days after induction, the mean FPG level was 112 mg/dl in Group I (30 mg/kg STZ), 217 mg/dl in Group II (40 mg/kg STZ), and 376 mg/dl in Group III (50 mg/kg STZ). Histology was normal in Group I but revealed altered islet structure in Groups II and III. Ultrastructure revealed intact D cells in all three groups. The focal mitochondria and Golgi complex swelling found in A and B cells was occasional in Group I and frequent in Groups II and III. Swelling of other organelles and reduction in the size and number of granules was further observed in Group III. It is our conclusion that the 30‐mg/kg body weight STZ produces mild changes while 50 mg/kg proves to be fatal. STZ at 40 mg/kg has a moderate effect on plasma glucose as well as on the islets of Langerhans at a cellular level. Microsc. Res. Tech. 63:274–281, 2004. © 2004 Wiley‐Liss, Inc.
Solving the asymmetric traveling salesman problem with periodic constraints
Authors: Paletta Giuseppe , Triki Chefi
Published: May 2004

In this article we describe a heuristic algorithm to solve the asymmetrical traveling salesman problem with periodic constraints over a given m‐day planning horizon. Each city i must be visited ri times within this time horizon, and these visit days are assigned to i by selecting one of the feasible combinations of ri visit days with the objective of minimizing the total distance traveled by the salesman. The proposed algorithm is a heuristic that starts by designing feasible tours, one for each day of the m‐day planning horizon, and then employs an improvement procedure that modifies the assigned combination to each of the cities, to improve the objective function. Our heuristic has been tested on a set of test problems purposely generated by slightly modifying known test problems taken from the literature. Computational comparisons on special instances indicate encouraging results. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(1), 31–37 2004
The legitimacy of social enterprise
Authors: Dart Raymond
Published: May 2004

Social enterprise has emerged as a businesslike contrast to the traditional nonprofit organization. This article develops an explanatory direction for social enterprise based on institutional perspectives rather than more traditional rational economic concepts. Through Suchman's typology of legitimacy (1995), the article argues that the origin and evolution of social enterprise is put into dramatically different focus, particularly through the concept of moral legitimacy. Moral legitimacy not only connects the overall emergence of social enterprise with neoconservative, pro‐business, and promarket political and ideological values that have become central in many nations in the Organization for Economic Cooperation and Development but also explains the observation that social enterprise is being more frequently understood and practiced in more narrow commercial and revenue‐generation terms.
Staffing, retention, and government funding: A case study
Authors: Akingbola Kunle
Published: May 2004

This study analyzes the implications of government‐contract funding on the staffing pattern of a nonprofit agency, the Canadian Red Cross, Toronto Region. Furthermore, the study explains the implications of the staffing pattern on services and on the agency's organization. Staffing is one area that the literature on nonprofit organizations has not adequately addressed.

The findings indicate that contract‐based funding leads to the hiring of temporary staff and affects the retention of employees. Although contract funding has some benefits, temporary staffing is detrimental to the agency's services. It affects not only employee recruitment and retention but also training. The results highlight how change in government funding from grants to contracts resulted in the agency's new staffing strategy and ultimately reduced the effectiveness of the services the agency provided to the community.
NAD(P)H:quinone oxidoreductase 1 null genotype is not associated with pediatric de novo acute leukemia
Authors: Sirma Sema , Agaoglu Leyla , Yildiz Inci , Cayli Dilara , Horgusluoglu Emrin , Anak Sema , Yuksel Lebriz , Unuvar Aysegul , Celkan Tiraje , Apak Hilmi , Karakas Zeynep , Devecioglu Omer , Ozbek Ugur
Published: May 2004

Background

NAD(P)H:quinone oxidoreductase1 (NQO1) is a two‐electron reductase that detoxifies quinones derived from the oxidation of phenolic metabolites of benzene. Exposure to benzene metabolites increases the risk of hematotoxicity and leukemia. NQO1 enzyme activity protects the cells against metabolites of benzene. C to T base substitution at nucleotide 609 of NQO1 cDNA (C609T) results in loss of enzyme activity. Low NQO1 activity may play a role in etiology of acute leukemia.

Procedure

We analyzed NQO1 C609T gene polymorphism using the PCR‐RFLP method in 273 patients with de novo acute leukemia (189 acute lymphoblastic leukemia (ALL), and 84 acute myeloid leukemia (AML) and 286 healthy volunteers to investigate the role of NQO1 polymorphism in the etiology of acute leukemia.

Results and Conclusions

The frequency of homozygosity for NOQ1 C609T polymorphism was 3.5% in the healthy control population and 2.5% in pediatric acute leukemia. The NQO1 C609T allele frequency was not statistically different in the children with acute leukemia in comparison to the controls (odds ratio (OR), 0.76; 95% confidence interval (CI), 0.58–1.01; P = 0.06). The distribution of NQO1 genotypes among children with acute leukemia was not statistically different from the control group (P = 0.13). These findings do not support the role of NQO1 C609T polymorphism in the etiology of de novo pediatric acute leukemia. © 2004 Wiley‐Liss, Inc.
Diazonium ion chemistry: replacement of H by alkyl at the central carbon accelerates an SN2 substitution reaction
Authors: Agnew Tara E. , Kim Hyun‐Joong , Fishbein James C.
Published: May 2004

The rate constants for hydrolysis of diazomethane, diazoethane and 1‐diazopropane in aqueous 5% acetonitrile at 25°C and ionic strength 1 M (NaClO4) were measured by stopped‐flow spectrophotometry. The pH‐rate profile for diazomethane hydrolysis exhibits a pH‐independent section in the lower pH range, 8–10, with a downward break at higher pH, as has been reported for slightly different reaction conditions. In the case of diazoethane and 1‐diazopropane, the reaction remains pH independent up to pH > 13. General acid catalysis of the hydrolysis reactions of diazomethane and diazoethane were examined in the pH‐independent regions. For a limited number of catalysts, the value of Brønsted α was 0.58 for both diazoalkanes. The downward break in the pH rate profile for diazomethane hydrolysis is consistent with what was previously concluded, rate‐limiting protonation by H2O in the pH‐independent region changing to rate‐limiting attack of water on the diazonium ion in the pH‐dependent region, the decrease in rate constant with increasing pH being attributed to deprotonation of the diazonium ion by hydroxide ion. The lack of a downward break in the pH–rate profiles for hydrolysis of the diazoethane and 1‐diazopropane is attributed specifically to the increase, relative to the methyldiazonium ion, in the rate constant for water attack on the ethyl‐ and 1‐propyldiazonium ions, perhaps by as much as >103‐fold. Copyright © 2004 John Wiley & Sons, Ltd.
Pre‐steady‐state kinetic studies of rat kidney γ‐glutamyl transpeptidase confirm its ping‐pong mechanism
Authors: Keillor Jeffrey W. , Ménard Annie , Castonguay Roselyne , Lherbet Christian , Rivard Caroline
Published: May 2004

The enzyme γ‐glutamyl transpeptidase (GGT) is implicated in cellular detoxification, the biosynthesis of leukotrienes and control of the physiological concentration of glutathione. It also plays important roles in Parkinson's disease, diabetes, apoptosis inhibition and cancer drug resistance. It catalyses the breakdown of its in vivo substrate, glutathione, by cleaving the amide bond between the γ‐glutamyl and the cysteinylglycine moieties. Threonine is proposed to act as the nucleophile of GGT in the formation of the γ‐glutamyl acyl enzyme intermediate during the acylation step. The γ‐glutamyl moiety is then transferred to a primary amine acceptor substrate (an amino acid or dipeptide) or to a water molecule, to form a compound containing a new isopeptide bond or glutamate in the transamidation or hydrolysis reactions, respectively. In spite of the importance of the role of GGT in human physiology, there is a lack of information about the mechanisms of its catalytic reactions, and in particular the nature of the intermediate formed during the acylation step. In order to gain insight into the formation of the acyl enzyme intermediate, different D‐γ‐glutamylanilides substituted in the para position with electron‐withdrawing and electron‐donating groups were used as donor substrates under conditions where water served as acceptor substrate. A Hammett plot with a slope of zero was obtained for the steady‐state hydrolysis reaction for which deacylation is the rate‐ limiting step. To confirm the ping‐pong mechanism, pre‐steady‐state kinetics of this reaction were then performed with the donor substrate D‐γ‐glutamyl‐p‐nitroanilide, which liberates the chromophore p‐nitroaniline. Experiments using a stopped‐ flow spectrometer and a rapid mix–quench apparatus gave biphasic traces with a burst up to ∼65 ms, the amplitude of which corresponds well with the concentration of the enzyme. These burst kinetics were also observed in the presence of L‐methionine at concentrations ∼15‐fold below its KM value, where deacylation would still be rate limiting. These observations are consistent with the formation of an intermediate during the rapid acylation step and support the modified ping‐pong mechanism proposed for GGT‐ mediated hydrolysis and aminolysis. Copyright © 2004 John Wiley & Sons, Ltd.
Hollow microstructures of polypyrrole doped by poly(styrene sulfonic acid)
Authors: Qu Liangti , Shi Gaoquan
Published: May 2004

Microstructures with hollow interiors, such as microspheres, microcrocks, microbowls, and micropumpkins, were prepared through the direct electrochemical oxidation of pyrrole in an aqueous solution of poly(styrene sulfonic acid) (PSSA). Scanning electron microscopy demonstrated that the microstructures possessed hollow interiors. The addition of polymeric doping ions made the skins of the microstructures very smooth, and several novel structures were observed. The morphology of the microstructures was simply modulated through changes in the electrochemical conditions. Raman and Fourier transform infrared characterizations indicated that the microstructures were made of conductive polypyrrole (PPy) doped by polymeric anions of poly(styrene sulfonate), and X‐ray diffraction showed that the microstructures were amorphous. Thermogravimetric analysis indicated that PPy–PSSA composite films with microstructures had higher thermal stability than pure PPy, PPy‐coated PSSA microspheres, and naphthalene sulfonic acid doped PPy microstructures. Furthermore, PPy–PSSA composite films with microstructures showed cation‐exchange behavior during the redox process in aqueous solutions of sodium dodecyl benzenesulfonate. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3170–3177, 2004
A Double Gaussian Beam Method for the Determination of Particle Size, Direction and Velocity
Authors: Castagner Jean Luc , Jones Alan R.
Published: May 2004

This paper describes a technique aimed at measuring particle size by light scattering from gaussian laser beams. The uncertainties in illumination due to the beam shape are avoided by determination of the direction and velocity. The method, which we arbitrarily called the Two Beam System (TBS), uses a simple birefringent prism to separate the incident laser beam into two orthogonally polarised overlapping parallel beams. The relative delay and amplitudes of the intensities scattered out of the orthogonal polarisations are indicative of the particle direction and velocity. Having obtained the direction of travel of the particle, its size is then obtained from the scattered intensity using Mie theory.
THE STRANGE TRIUMPH OF HUMAN RIGHTS, 1933–1950
Authors: MAZOWER MARK
Published: May 2004

This article explores the origins of the UN's commitment to human rights and links this to the wartime decision to abandon the interwar system of an international regime for the protection of minority rights. After 1918, the League of Nations developed a comprehensive machinery for guaranteeing the national minorities of eastern Europe. But by 1940 the League's policies were widely regarded as a failure and the coalition of forces which had supported them after the First World War had disintegrated. German abuse of the system after 1933, and the Third Reich's use of ethnic German groups as fifth columns to undermine the Versailles settlement were cited by east European politicians as sufficient justification for a new approach which would combine mass expulsion, on the one hand, with a new international doctrine of individual human rights on the other. The Great Powers supported this because they thereby escaped the specific commitments which the previous arrangements had imposed on them, and which Russian control over post-war eastern Europe rendered no longer practicable. But they also supported it because the new rights regime had no binding legal force. In respect, therefore, of the degree to which the principle of absolute state sovereignty was threatened by these arrangements, the rights regime of the new UN represented a considerable weakening of international will compared with the interwar League. But acquiescing in a weaker international organization was probably the price necessary for US and Soviet participation.
CNS involvement in Fabry disease: Clinical and imaging studies before and after 12 months of enzyme replacement therapy
Authors: Jardim L. , Vedolin L. , Schwartz I. V. D. , Burin M. G. , Cecchin C. , Kalakun L. , Matte U. , Aesse F. , Pitta‐Pinheiro C. , Marconato J. , Giugliani R.
Published: May 2004

Summary: We report the clinical and radiological central nervous system (CNS) findings of 8 Fabry disease patients, before (8/8) and after (7/8) 12 months of enzyme replacement therapy (ERT) with agalsidase‐alpha. Eight biochemically proven Fabry disease patients (from four families) were included. Patients were evaluated at baseline and at regular intervals during 12 months of ERT. Evaluations included a thorough, standardized neurological examination, and magnetic resonance imaging (MRI) and angiography (MRA). Brain proton magnetic resonance spectroscopy (MRS) was also performed in 5/8 patients. The presence and location of grey‐ and white‐matter lesions, the presence of vascular occlusion or ectasia on MRA and the metabolite ratios on MRS were determined, as well as their relation to age, symptoms and neurological examination. Neurological examination showed few abnormalities in these patients: scores varied (on a 0–100 scale) from zero to 5, at baseline and in the 12th month of ERT. The most consistent findings on MRI were asymmetric, widespread patterns of deep white‐matter (WM) lesions, hyperintense on T2 and FLAIR‐weighted images, found in 4/8 patients at baseline, predominantly in frontal and parietal lobes. These lesions did not correlate with other clinical variables, although there was a trend towards an association of the lesions with age and hearing loss. The youngest patient with MRI lesions was 24 years old. After 12 months of ERT, MRI was normal in 3/7, showed the same WM lesions in 2/7, and showed worsening of WM lesions in 2/7 patients (from the same family). Abnormal MRS metabolite ratios were detected at baseline in 4/5 patients. While neurological examination remained almost normal during the 12 months of ERT, new small‐vessel CNS involvement still appeared in 2/7 patients. We do not know why ERT was not able to prevent this in these two related male patients. This could be due either to their older ages (46 and 36 years), or to a more pathogenic mutation. We conclude that MRI was more sensitive than neurological examination in detecting CNS involvement and progression in Fabry disease in the time interval studied.
Surveilling Strange Materialities: Categorisation in the Evolving Geographies of FMD Biosecurity
Authors: Donaldson Andrew , Wood David
Published: May 2004

The 2001 foot and mouth disease (FMD) epidemic in the United Kingdom resulted in the popularisation of the concept of biosecurity. At its most basic, biosecurity refers to simple cleansing and disinfecting, but during the FMD epidemic it became associated with a powerful system of surveillance. We characterise surveillance as a thing in itself, a mode of ordering that can be added to others. The establishment and maintenance of categories are fundamental to the practice of surveillance, but social studies of surveillance have not yet fully realised the way such categorisation operates within the nonhuman and the spatial. Strange materialities are those things which do not quite belong within a particular order. We examine the actions of surveillance in the world of strange materialities that was the FMD epidemic. Here we see that surveillant practices acted on the nonhuman FMD virus by constructing territories to control humans. Surveillance seems to proceed as the translation of a worldview (a system of categorisation) into materiality and we conclude with some thoughts on what this may mean for geographical studies of technical, biological, and human materialities in which surveillant processes are at work.