bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of hydrogen trapping sites in submerged arc weld metal using tritium autoradiography
Authors: Kasuya T. , Saito H.
Published: June 2004

Hydrogen trapping sites in a submerged arc welding (SAW) weld metal were investigated using tritium autoradiography. Diffusible tritium was able to escape from the present specimens within 72 h, and transmission electron microscope (TEM) observation of thin foil specimens that were kept at room temperature for 72 h before tritium autoradiography showed that dislo cations were the main trapping sites. No evidence was found to indicate that oxides or carbides behaved as trapping sites, but further investigations into this are needed. The present experimental procedure is expected to provide a powerful method for analysis of hydrogen trapping sites in weld metal.
Modelling and prediction of cut shape for plasma arc cutting based on artificial neural network
Authors: Wang J. Y. , Kusumoto K. , Nezu K.
Published: June 2004

An artificial neural network approach for the modelling of plasma arc cutting processes is introduced. Neural network models have been proposed for predicting the cut shape and estimating the special cutting variables. The implementation of artificial neural networks in the modelling of cutting processes is discussed in detail. The performance of the neural networks in modelling is presented and evaluated using actual cutting data. Moreover, prediction applications of the above neural network models are described for various cutting conditions. It is shown that estimated results based on the proposed models agree well with experimental data; the neural network models yield good prediction results over the entire range of cutting process parameters spanned by the training data. The testing and prediction results show the effectiveness and satisfactory prediction accuracy of the artificial neural network modelling. The developed models are applicable to carbon steel.
Effect of welding process on fatigue crack growth behaviour of ASTM 517 ‘F’ grade steel weld metals
Authors: Balasubramanian V. , Guha B.
Published: June 2004

The fatigue crack growth behaviours of two weld metals deposited by shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes have been compared. Load carrying cruciform joints, with a lack of penetration (LOP) defect, were fabricated from high strength, quenched and tempered steel of ASTM 517 ‘F’ grade. Fatigue crack growth experiments were carried out in a vertical pulsator (Schenck 200 kN capacity) with a frequency of 30 Hz under constant amplitude loading (stress ratio R = 0). It was found that the fatigue crack growth resistance of the weld metal deposited by the SMAW process is superior, compared to the weld metal deposited by the FCAW process. The high heat input involved in the FCAW process probably contributes to the changes in weld metal properties, which result in a change in fatigue crack growth behaviour.
Prediction of hardness distribution in steel heat affected zone
Authors: Kasuya T. , Hashiba Y.
Published: June 2004

A practical method to predict the heat affected zone (HAZ) hardness distribution was studied by considering the effects of prior austenite grain size and tempering on hardenability. For conventionally rolled and thermomechanically processed steels (400–490 MPa grade steels), the hardness distribution between the fusion and Ac3 lines can be fairly well predicted by introducing the effect of grain size into the maximum HAZ hardness prediction method of Yurioka et al. For a quenched and tempered steel with boron addition (780 MPa grade steel), as the maximum hardness is obtained a small distance away from the fusion line, the present method cannot adequately predict its HAZ hardness. Hardness at the Ac1 line for thermomechanically processed and quenched and tempered steels can be predicted with the present method, in which the parameter introduced by Inoue has been used to estimate the effect of tempering.
Effect of process parameters on stability of water jet cutting
Authors: Jou M.
Published: June 2004

The ultrahigh pressure water jet is a novel means of cutting and cleaning surfaces. In the past two decades, researchers have been studying the characteristics of the water jet, and have tried to control its cutting process. However, existing knowledge about water jet cutting is still ambiguous. Thus, it cannot satisfy the requirement of precise control. In this paper, the linear stabilised theory is applied to analyse theoretically the relationship of the nozzle diameter and wave num ber in the water flow with the stability of the water jet. Theoretical conclusions satisfy the experimental observations obtained.
Prediction of dimensional changes during fabrication of thin shell ship hull bottom units
Authors: Mandal N.R.
Published: June 2004

The cumulative effect of distortion resulting from the welding of butts and stiffeners during the fabrication of ship hull units leads to an overall change in dimensions. This dimensional inaccuracy causes further erection difficulties owing to mismatch and misalignment. This problem has been addressed in the present work using the far field–near field concept. The near field has been assumed to extend from the weld line to a location where the peak temperature attained is 350°C, and the rest of the plate is far field. Plastic deformation is expected only in the near field, whereas the far field behaves elastically throughout the heating and cooling cycle. Measurements carried out on two units show a fairly good agreement with the calculated values.
Optimised post-weld heat treatment procedures and heat input for welding 17–4PH stainless steel
Authors: Bhaduri A.K. , Gill T.P.S. , Srinivasan G. , Sujith S.
Published: June 2004

Post-weld heat treatment (PWHT) procedures and heat input during welding of 17–4PH stainless steel, using matching chemistry consumables, have been optimised in relation to its microstructural condition before welding based on room temperature tensile properties. The 17–4PH stainless steel was welded in two different prior microstructural conditions, namely, condition A (solution treated) and condition H1150 (overaged), using three different heat inputs of 0·27, 0·48, and 0·72 kJ mm-1, and post-weld heat treated to condition H900 (aged) or condition H1150 (over aged), using different heat treatment procedures. Room temperature tensile tests were carried out to study the combined effects of prior microstructural condition, heat input during welding, and PWHT procedures.
Sensing metal inert gas process by measuring wire feedrate and current
Authors: Huismann G. , Hoffmeister H.
Published: June 2004

Current and wire feedrate are coupled in a complicated manner in the metal inert gas (MIG) welding process. To investigate this interaction, a model of the melting process was established. The model is based on the physical properties of the wire and the energy flow in the MIG process. This model was used to study the influence of the different types of energy transfer to the wire. The contact resistance, stickout length, current, and anodic heat all influence the melting rate of the wire. This knowledge could be used to control the MIG process. In the present case, measurements of the current and wire feedrate can be taken to obtain information on the physical status of the process. Control of the process is possible with this information.
Numerical modelling and experimental determination of temperature distribution during manual metal arc welding
Authors: Murugan S. , Kumar P.V. , Gill T.P.S. , Raj B. , Bose M.S.C.
Published: June 2004

Welding is a highly reliable and efficient metal joining process. Manual metal arc (MMA) welding is very widely used in industry. The temperature distribution that occurs during welding affects the material microstructure, hardness, and the residual stresses present in the material after welding. In the present work, the temperature distribution during bead on plate welding using MMA welding was experimentally determined for AISI type 304 stainless steel plates and low carbon steel plates of thickness 6 and 12 mm. A three-dimensional computer model based on the control volume method has been developed to predict the temperature distribution in the heat affected zone (HAZ) and in the base plate region of the bead on plate welds, using the weld parameters as input data to the computer model. In this computer model, the heat energy used to melt the electrode is considered as a separate heat flux term and the remaining heat supplied by the welding arc is considered as another heat flux term. A good match between the experimental results and the theoretical predictions was obtained. Using the computer model, the time taken to cool from 800 to 500°C in the coarse grained HAZ (close to the fusion line) of low carbon steel specimens was calculated. From this cooling time and the chemical composition of the material, the maximum hardness in the coarse grained HAZ was predicted. Microhardness measurement in the same region of the welded plates was carried out. The experimentally measured values and predicted results match closely.
Integration of three high power Nd–YAG lasers to one beam and its application in stainless steel welding
Authors: Fujinaga S. , Miura H. , Narikiyo T. , Katayama S. , Ohmori A. , Matsunawa A.
Published: June 2004

An Nd–YAG laser processing system has been developed in which the beams of three Nd–YAG lasers (two 2·0 kW continuous wave oscillators and one 1·5 kW pulsed oscillator) were combined at the input end of a single optical fibre and transmitted through the optical fibre. The power distribution of the integrated beam, even at the defocused point of the processing optics, was not split between the three beams. Complex pulse waveform control was therefore possible. The effect of the waveforms on penetration depth was examined. Penetration depth for the rectangular modulated laser beam superimposed on the pulse laser beam with a delay was deeper than that for the rectangular modulated laser beam and the continuous laser beam, even under the same average power condition. The effective delay was 1–3 ms. Deepest penetration depth for the rectangular modulated laser beam superimposed on the pulse laser beam was 1·7 times that for the continuous laser beam.
Effect of scandium and titanium–boron on grain refinement and hot cracking of aluminium alloy 7108
Authors: Mousavi M.G. , Cross C.E. , Grong Ø.
Published: June 2004

The effect of scandium and titanium–boron (Tibor) additions on the solidification behaviour of castings and welds of aluminium alloy 7108 has been investigated. A circular patch test was adopted to evaluate the effects of these elements on the hot cracking suscepti bility of welds made on cast coupons treated with different grain refiner additions. It was observed that grain size, as well as cracking susceptibility, decreased with increasing amounts of scandium and that hot cracking was completely eliminated at scandium additions above 0·25 wt-%. A more pronounced grain refining effect in welds was observed with Tibor and, in addition, no hot cracking was observed with Tibor additions as low as 0·02 wt-%Ti (0·004 wt-%B). Castings, however, were more effectively grain refined with scandium, achieving a finer grain size than with Tibor.
Biological, Physiological, Pathophysiological, and Pharmacological Aspects of Ghrelin
Authors: van der Lely Aart J. , Tschöp Matthias , Heiman Mark L. , Ghigo Ezio
Published: June 2004

Ghrelin is a peptide predominantly produced by the stomach. Ghrelin displays strong GH-releasing activity. This activity is mediated by the activation of the so-called GH secretagogue receptor type 1a. This receptor had been shown to be specific for a family of synthetic, peptidyl and nonpeptidyl GH secretagogues. Apart from a potent GH-releasing action, ghrelin has other activities including stimulation of lactotroph and corticotroph function, influence on the pituitary gonadal axis, stimulation of appetite, control of energy balance, influence on sleep and behavior, control of gastric motility and acid secretion, and influence on pancreatic exocrine and endocrine function as well as on glucose metabolism. Cardiovascular actions and modulation of proliferation of neoplastic cells, as well as of the immune system, are other actions of ghrelin. Therefore, we consider ghrelin a gastrointestinal peptide contributing to the regulation of diverse functions of the gut-brain axis. So, there is indeed a possibility that ghrelin analogs, acting as either agonists or antagonists, might have clinical impact.
Androgens and Bone
Authors: Vanderschueren Dirk , Vandenput Liesbeth , Boonen Steven , Lindberg Marie K. , Bouillon Roger , Ohlsson Claes
Published: June 2004

Loss of estrogens or androgens increases the rate of bone remodeling by removing restraining effects on osteoblastogenesis and osteoclastogenesis, and also causes a focal imbalance between resorption and formation by prolonging the lifespan of osteoclasts and shortening the lifespan of osteoblasts. Conversely, androgens, as well as estrogens, maintain cancellous bone mass and integrity, regardless of age or sex. Although androgens, via the androgen receptor (AR), and estrogens, via the estrogen receptors (ERs), can exert these effects, their relative contribution remains uncertain. Recent studies suggest that androgen action on cancellous bone depends on (local) aromatization of androgens into estrogens. However, at least in rodents, androgen action on cancellous bone can be directly mediated via AR activation, even in the absence of ERs.

Androgens also increase cortical bone size via stimulation of both longitudinal and radial growth. First, androgens, like estrogens, have a biphasic effect on endochondral bone formation: at the start of puberty, sex steroids stimulate endochondral bone formation, whereas they induce epiphyseal closure at the end of puberty. Androgen action on the growth plate is, however, clearly mediated via aromatization in estrogens and interaction with ERα. Androgens increase radial growth, whereas estrogens decrease periosteal bone formation. This effect of androgens may be important because bone strength in males seems to be determined by relatively higher periosteal bone formation and, therefore, greater bone dimensions, relative to muscle mass at older age. Experiments in mice again suggest that both the AR and ERα pathways are involved in androgen action on radial bone growth. ERβ may mediate growth-limiting effects of estrogens in the female but does not seem to be involved in the regulation of bone size in males.

In conclusion, androgens may protect men against osteoporosis via maintenance of cancellous bone mass and expansion of cortical bone. Such androgen action on bone is mediated by the AR and ERα.
Central Fat Mass Versus Peripheral Fat and Lean Mass: Opposite (Adverse Versus Favorable) Associations with Arterial Stiffness? The Amsterdam Growth and Health Longitudinal Study
Authors: Ferreira Isabel , Snijder Marieke B. , Twisk Jos W. R. , van Mechelen Willem , Kemper Han C. G. , Seidell Jacob C. , Stehouwer Coen D. A.
Published: June 2004

Central and peripheral fatness seem to confer opposite (i.e. adverse vs. protective) effects on cardiovascular risk, but how this occurs is not clear. In addition, the role of peripheral lean mass needs to be elucidated. We therefore investigated, in 336 (175 women) 36-yr-old and apparently healthy adults, the relationship between trunk fat, peripheral fat, and peripheral lean mass on the one hand, and estimates of stiffness of three large arteries on the other. Body composition was assessed by dual-energy x-ray absorptiometry. Arterial properties were assessed by ultrasound imaging. We found that 1) trunk fat was positively (i.e. adversely) associated with stiffness of the carotid and femoral arteries, whereas peripheral fat was inversely (i.e. favorably) associated with stiffness of the brachial and the carotido-femoral segment; 2) peripheral lean mass was positively associated with arterial diameter and carotid compliance and inversely associated with stiffness of the carotido-femoral segment; and 3) after adjustment for the other body composition variables, the above-mentioned associations remained, but peripheral fat in addition became, if anything, favorably associated with stiffness of the femoral artery. We conclude that trunk fat is adversely associated with large artery stiffness, whereas some degree of protection is conferred by peripheral fat and lean mass.
Neonatal Diabetes Mellitus and Neonatal Polycystic, Dysplastic Kidneys: Phenotypically Discordant Recurrence of a Mutation in the Hepatocyte Nuclear Factor-1β Gene Due to Germline Mosaicism
Authors: Yorifuji Tohru , Kurokawa Keiji , Mamada Mitsukazu , Imai Tsuyoshi , Kawai Masahiko , Nishi Yoshikazu , Shishido Seiichiro , Hasegawa Yukihiro , Nakahata Tatsutoshi
Published: June 2004

Mutations in the gene coding for hepatocyte nuclear factor-1β (HNF-1β) have been known to cause a form of maturity-onset diabetes of the young (MODY5), which is usually characterized by dominantly inherited adolescence-onset diabetes mellitus associated with renal cysts. This report, however, describes recurrence of a novel missense mutation in the HNF-1β gene, S148W (C443G), in two sibs, one with neonatal diabetes mellitus and the other with neonatal polycystic, dysplastic kidneys leading to early renal failure. The former patient had only a few small renal cysts with normal renal functions, and the latter had only a transient episode of hyperglycemia, which resolved spontaneously. Interestingly, both parents were clinically unaffected, and PCR restriction fragment length polymorphism analysis showed that the mother was a low-level mosaic of normal and mutant HNF-1β, which suggested that the recurrence was caused by germline mosaicism. This is the first report of permanent neonatal diabetes mellitus caused by a mutation of the HNF-1β gene as well as the first report of germline mosaicism of this gene. In addition, the two cases described here show that additional factors, genetic or environmental, can have a significant influence on the phenotypic expression of HNF-1β mutations.
Serum Haptoglobin: A Novel Marker of Adiposity in Humans
Authors: Chiellini C. , Santini F. , Marsili A. , Berti P. , Bertacca A. , Pelosini C. , Scartabelli G. , Pardini E. , López-Soriano J. , Centoni R. , Ciccarone A. M. , Benzi L. , Vitti P. , Del Prato S. , Pinchera A. , Maffei M.
Published: June 2004

Haptoglobin (Hp) is a glycoprotein involved in the acute phase response to inflammation. Our previous findings indicate that Hp mRNA and protein are present in the adipose tissue of rodents and that Hp gene expression is up-regulated in obese models. The aim of the present study was to establish whether Hp could be considered a marker of obesity in humans. In 312 subjects, serum Hp was correlated directly with body mass index (BMI), leptin, C-reactive protein (CRP), and age. In a multivariate stepwise regression analysis, BMI and CRP were independent determinants of serum Hp in females, with BMI having the strongest effect. CRP and age were independent determinants of serum Hp in males, although explaining only a modest percentage of the total variability. Serum Hp was positively associated with body fat, as assessed by dual-energy x-ray absorptiometry, both in female and in male groups. The level of significance improved when serum Hp was analyzed against fat mass adjusted for lean mass. Finally, Northern and Western blot analyses performed in biopsies of sc abdominal fat from 20 obese individuals showed the presence of Hp mRNA and protein in the human adipose tissue.

In conclusion, serum Hp constitutes a novel marker of adiposity in humans, and the adipose tissue likely contributes to determine its levels.
Race/Ethnic Issues in Obesity and Obesity-Related Comorbidities
Authors: Cossrow Nicole , Falkner Bonita
Published: June 2004

The prevalence of obesity is increasing among all age and racial groups in the United States. There is, however, a disproportionate rise in the prevalence of obesity among African-Americans and Hispanic/Mexican Americans. Obesity is a major contributor to the insulin resistant syndrome (IRS), a condition of multiple metabolic abnormalities that is a precursor to type 2 diabetes, and confers a high risk for cardiovascular events. The estimated prevalence of IRS is also greater in Mexican Americans and African-Americans than in Caucasians. The IRS is identifiable in children, and as with adults, there are racial differences in its expression even at a young age. The obesity-associated diseases, including diabetes and hypertension, are found at higher rates within the minority races compared with Caucasians. However, there are differences, in that obesity-related hypertension occurs at higher rates among African-Americans, and obesity-related diabetes occurs at higher rates among Mexican Americans. Race/ethnic differences in lifestyle behaviors and economic disadvantage may account for some of the race disparity in obesity-related diseases and disease outcomes. Environmental factors, however, do not explain all of the race disparity in disease expression, indicating that there are genetic/molecular factors that are operational as well.
Proopiomelanocortin and Energy Balance: Insights from Human and Murine Genetics
Authors: Coll Anthony P. , Farooqi I. Sadaf , Challis Benjamin G. , Yeo Giles S. H. , O’Rahilly Stephen
Published: June 2004

Proopiomelanocortin (POMC) undergoes extensive and tissuespecific posttranslational processing to yield a range of biologically active peptides. Historically, the most clearly defined roles of these peptides are in the control of adrenal steroidogenesis by corticotroph-derived ACTH and skin pigmentation by αMSH. However, a rapidly expanding body of work has established that POMC-derived peptides synthesized in neurons of the hypothalamus play a central role in the control of energy homeostasis. We review how inherited abnormalities in POMC synthesis and processing and defects in the action of POMC-derived peptides in both humans and mice have helped shape our current understanding of the importance of the melanocortin system in human energy balance.
Abdominal Obesity and Dyslipidemia in the Metabolic Syndrome: Importance of Type 2 Diabetes and Familial Combined Hyperlipidemia in Coronary Artery Disease Risk
Authors: Carr Molly C. , Brunzell John D.
Published: June 2004

Regional body fat distribution has an important influence on metabolic and cardiovascular risk factors. Increased abdominal (visceral) fat accumulation is a risk factor for coronary artery disease (CAD), dyslipidemia, hypertension, stroke, and type 2 diabetes. The recent emphasis on treatment of the dyslipidemia of the metabolic syndrome (hypertriglyceridemia, reduced high-density lipoprotein, and increased small, dense low-density lipoprotein particle number) has compelled practitioners to consider lipid-lowering therapy in a greater number of their patients, as one in two individuals over age 50 has the metabolic syndrome. Individuals with the metabolic syndrome typically have normal low-density lipoprotein cholesterol levels, and current lipid-lowering guidelines may underestimate their cardiovascular risk. Two subgroups of patients with the metabolic syndrome are at particularly high risk for premature CAD. One, individuals with type 2 diabetes, accounts for 20–30% of early cardiovascular disease. The second, familial combined hyperlipidemia, accounts for an additional 10–20% of premature CAD. Familial combined hyperlipidemia is characterized by the metabolic syndrome in addition to a disproportionate elevation of apolipoprotein B levels. The measurement of fasting glucose and apolipoprotein B, in addition to the fasting lipid profile, can help to estimate CAD risk in patients with the metabolic syndrome.
Pineal organs of deep-sea fish: photopigments and structure
Authors: Bowmaker James K. , Wagner Hans-Joachim
Published: June 2004

We have examined the morphology and photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish(Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths(Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal photopigment was spectrally distinct from the retinal rod pigment, with λmax displaced to longer wavelengths, between ∼485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment withλ max at 478 nm, but the pineal pigment hasλ max at ∼515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod photopigment.
Colour vision in the glow-worm Lampyris noctiluca (L.)(Coleoptera: Lampyridae): evidence for a green-blue chromatic mechanism
Authors: Booth David , Stewart Alan J. A. , Osorio Daniel
Published: June 2004

Male glow-worms Lampyris noctiluca find their bioluminescent mates at night by phototaxis. There is good evidence that location of mates by lampyrid beetles is achieved by a single spectral class of photoreceptor,whose spectral sensitivity is tuned to the bioluminescent spectrum emitted by conspecifics, and is achromatic. We ask whether glow-worm phototaxis involves interactions between two spectral classes of photoreceptor. Binary choice experiments were conducted in which males were presented with artificial light stimuli that differ in spectral composition. The normal preference for a green stimulus (λmax=555 nm), corresponding to the bioluminescence wavelength produced by signalling females, was significantly reduced by adding a blue (λmax=485 nm) component to the signal. This implies an antagonistic interaction between long- and short-wavelength sensitive photoreceptors, suggesting colour vision based on chromatic opponency. Cryosections showed a band of yellow filter pigment in the fronto-dorsal region of the male compound eye, which could severely constrain colour vision in the dim conditions in which the insects signal. This apparent paradox is discussed in the context of the distribution of the pigment within the eye and the photic niche of the species.
Dopamine stimulates snail albumen gland glycoprotein secretion through the activation of a D1-like receptor
Authors: Mukai S. T. , Kiehn L. , Saleuddin A. S. M.
Published: June 2004

The catecholamine dopamine is present in both the central nervous system and in the peripheral tissues of molluscs, where it is involved in regulating reproduction. Application of exogenous dopamine to the isolated albumen gland of the freshwater pulmonate snail Helisoma duryi (Wetherby) induces the secretion (release) of perivitelline fluid. The major protein component of the perivitelline fluid of Helisoma duryi is a native 288 kDa glycoprotein that is secreted around individual eggs and serves as an important source of nutrients for the developing embryos. The secretion of glycoprotein by the albumen gland is a highly regulated event that must be coordinated with the arrival of the fertilized ovum at the carrefour (the region where the eggs receive albumen gland secretory products). In order to elucidate the intracellular signalling pathway(s) mediating dopamine-induced glycoprotein secretion, albumen gland cAMP production and glycoprotein secretion were measured in the presence/absence of selected dopamine receptor agonists and antagonists. Dopamine D1-selective agonists dihydrexidine,6,7-ADTN and SKF81297 stimulated cAMP production and glycoprotein secretion from isolated albumen glands whereas D1-selective antagonists SCH23390 and SKF83566 suppressed dopamine-stimulated cAMP production. Dopamine D2-selective agonists and antagonists generally had no effect on cAMP production or protein secretion. Based on the effects of these compounds, a pharmacological profile was obtained that strongly suggests the presence of a dopamine D1-like receptor in the albumen gland of Helisoma duryi. In addition,secretion of albumen gland glycoprotein was not inhibited by protein kinase A inhibitors, suggesting that dopamine-stimulated protein secretion might occur through a protein kinase A-independent pathway.
Total Synthesis of Bistratamide G, a Metabolite of the Philippines Ascidian Lissoclinum bistratum, from Dehydrotripeptides
Authors: Shin Chung-gi , Abe Chieko , Yonezawa Yasuchika
Published: June 2004

Total synthesis of triheterocyclic cyclopeptide bistratamide G, a metabolite from the Philippines ascidian Lissoclinum bistratum, was first achieved from two kinds of dehydrotripeptides.
Preparation and Characterization of Tungsten-substituted Molybdenum Disulfide Nanorods
Authors: Xia Junbao , Xu Zhude , Chen Weixiang , Nie Qiulin , Li Guohua
Published: June 2004

The tungsten-substituted molybdenum disulfide nanorods were synthesized through a pyrolysis process. The rod-shaped trisulfide precursor was prepared using a reversed micelle based method. The tungsten-substituted molybdenum disulfide nanorods were obtained by thermal decomposition of the as-prepared precursor. Energy dispersive spectroscopy identified that the chemical composition of the final product was Mo0.95W0.05S2. The produced nanorods were further characterized with X-ray power diffraction and transmission electron microscopy.
Spontaneous Assembly Formation of Cyclic Dimer of β-Amino Acid in Water
Authors: Fujimura Futoshi , Fukuda Makoto , Sugiyama Junji , Morita Tomoyuki , Kimura Shunsaku
Published: June 2004

A novel cyclic dimer composed of chiral l-β-homoalanine was synthesized, and the formation of molecular assembly in water was investigated. The cyclic dimer was found to spontaneously form a spherical assembly with diameter of 40–100 nm in water. The cyclic dimer takes a boat conformation with cis-amide configuration, and forms intermolecular hydrogen bondings in the assembly. The assembling property of the cyclic dimer of β-amino acid is distinct from that of α-amino acid.
Useful Synthesis of Fragment A–C–D of a Thiostrepton-type Macrocyclic Antibiotic, Thiocilline I
Authors: Suzuki Shuusuke , Yonezawa Yasuchika , Shin Chung-gi
Published: June 2004

Useful synthesis of the main Fragment A–C–D segment constructing a thiostrepton-type macrocyclic antibiotic, thiocilline I, was first achieved by coupling of the 2,3,6-polythiazolesubstituted pyridine skeleton (Fragment A–C) with Fragment D.
A New Route to Control Product Selectivity in the Oxidative Dehydrogenation of Cyclohexane and Cyclohexene
Authors: Zhu Yujun , Li Jing , Yang Xiangguang , Wu Yue
Published: June 2004

The product selectivity can be controlled by adding acetic acid in feed over vanadium phosphate (VPO) in gas phase oxidative dehydrogenation (ODH), in which cyclohexane and cyclohexene are oxidized to cyclohexene and 1,3-cyclohexadiene (1,3-CHD), respectively, at almost 100% selectivity. This approach is also an efficient method to capture the very unstable intermediates in the mechanism study.
Cobalt Ferrite Nanoparticles Prepared by Coprecipitation/Mechanochemical Treatment
Authors: Yang Huaming , Zhang Xiangchao , Tang Aidong , Qiu Guanzhou
Published: June 2004

Cobalt ferrite (CoFe2O4) nanoparticles have been prepared by chemical coprecipitation, mechanical milling and subsequent thermal treatment. Sodium chloride was added as a diluent during mechanical milling to avoid agglomeration of the particles. Thermal treatment of the as-milled powder at 600 °C produces well-crystallized CoFe2O4 nanoparticles with an average crystal size of 22.5 nm. The mechanism of nanoparticle growth was discussed.
Periodic Pulse Electrodeposition to Synthesize Ultra-high Density CdS Nanowire Arrays Templated by SBA-15 Mesoporous Films
Authors: Gu Jinlou , Shi Jianlin , Chen Hangrong , Xiong Liangming , Shen Weihua , Ruan Meilin
Published: June 2004

The high-density CdS nanowire arrays, which are the negative replica of the parent mesoporous thin films with a stoichiometric composition, have been synthesized through a newly developed periodic pulse electrodeposition route.
Cobalt-Catalyzed Allylic Substitution Reaction of Allylic Ethers with Phenyl and Trimethylsilylmethyl Grignard Reagents
Authors: Mizutani Keiya , Yorimitsu Hideki , Oshima Koichiro
Published: June 2004

Treatment of cinnamyl methyl ether with phenylmagnesium bromide in ether in the presence of CoCl2[1,5-bis(diphenylphosphino)pentane] affords 1,3-diphenylpropene in good yield. Similar allylic substitution reaction with trimethylsilylmethylmagnesium chloride proceeded smoothly to yield homoallylsilanes. α,β-Unsaturated aldehyde acetal also underwent allylic substitution.
Facile Oxidation of Aldehydes to Esters Using S·SnO2/SBA-1–H2O2
Authors: Qian Guang , Zhao Rui , Ji Dong , Lu Gaomeng , Qi Yanxing , Suo Jishuan
Published: June 2004

A highly efficient, mild, and simple procedure has been described for the oxidation of aldehydes to corresponding esters in alcohols with S·SnO2/SBA-1 as catalyst and H2O2 as the oxidant, and the catalytic systems can be used in the preparation of a broad range of esters. Oxidation of aldehydes to corresponding esters utilizing H2O2 as the oxidant without any metal catalyst is also reported.
Synthesis of Artificial Opals with Uniform Mesoporous Silica Spheres
Authors: Chen Chau-Nan , Lin Hong-Ping , Tsai Chih-Pin , Tang Chin-Yuan
Published: June 2004

The mesoporous silica submicron-spheres (80–200 nm) with a small dispersion in diameter (< 10%) as the building blocks of the artificial mesoporous silica opals have been synthesized using quaternary ammonium surfactant as template in an aqueous solution of suitable polarity at near neutral condition of pH = 7.0–9.0.
Preparation of Water-soluble PEGylated Semiconductor Nanocrystals
Authors: Kang Eui-Chul , Ogura Atsuhiko , Kataoka Kazunori , Nagasaki Yukio
Published: June 2004

We describe the synthesis of water-soluble PEGylated semiconductor nanocrystals and the characterization of their optical properties and colloidal stability by fluorescence and UV spectrometers. The fluorescence intensity of PEGylated CdSe/ZnS in PBS buffer was observed to be 75% of the initial values of conventional CdSe/ZnS in chloroform. The PEGylated CdSe/ZnS exhibited higher fluorescence intensity than PEGylated CdSe and CdSe/CdS in PBS buffer. The colloidal stability of PEGylated QDs in PBS buffer was estimated by transmittance as a function of time at 37 °C. The PEGylated CdSe/ZnS showed a colloidal stable dispersion in PBS buffer during 24 h.
Reversible Optical Rotation Change According to the Enantiospecific Photochromic Reaction of [2.2]Metacyclophan-1-ene
Authors: Takeshita Michinori , Yamato Takehiko
Published: June 2004

Chiral [2.2]metacyclophan-1-ene undergoes an enantiospecific photochromic reaction along with a photoreversible optical rotation change at the wavelength where both photoisomers never absorb. This enables us to carry out a non-destructive read-out of the photomemory made by the photochromic [2.2]metacyclophan-1-ene.
Novel Photochromic Behavior of Benzoylhemithioindigo Based on Photodimerization
Authors: Tanaka Kiyoshi , Taguchi Kazuto , Iwata Satoru , Irie Takayuki
Published: June 2004

Benzoyl-substituted hemithioindigo 1 has a novel type of photochromic behavior based on the formation of the photoinduced [2+4] cycloadduct; that is, irradiation of 1 produces the cycloadduct 2 with all trans-configurations between the adjacent carbonyl moieties; this is completely dissociated back to 1 on heating.
A Diffusion Model for Growth Stocks
Authors: Kou S. C. , Kou S. G.
Published: June 2004

Since growth stocks tend to have low or even negative earnings and high volatility, it is a great challenge to derive a meaningful mathematical model within the traditional valuation framework. This paper attempts to derive a suitable diffusion model for growth stocks by using the idea of size distribution. Numerical illustration of the model based on the data covering the time period of the recent boom and burst of the “Internet bubble” is also presented.
Three-Dimensional Microarray Compared with PCR–Single-Strand Conformation Polymorphism Analysis/DNA Sequencing for Mutation Analysis of K-ras Codons 12 and 13
Authors: Maekawa Masato , Nagaoka Tomonori , Taniguchi Terumi , Higashi Hitomi , Sugimura Haruhiko , Sugano Kokichi , Yonekawa Hiroyuki , Satoh Takatomo , Horii Toshinobu , Shirai Naohito , Takeshita Akihiro , Kanno Takashi
Published: June 2004

Background: We developed a rapid, precise, and accurate microarray-based method that uses a three-dimensional platform for detection of mutations.

Methods: We used the PamChip® microarray to detect mutations in codons 12 and 13 of K-ras in 15 cell lines and 81 gastric or colorectal cancer tissues. Fluorescein isothiocyanate-labeled PCR products were analyzed with the microarray. We confirmed the microarray results with PCR–single-strand conformation polymorphism (SSCP) analysis and DNA sequencing.

Results: We could correctly identify wild-type, heterozygous, and homozygous mutant genotypes with the PamChip microarray in <3.5 h. The array data were consistent with those of PCR-SSCP analysis and DNA sequencing. All 15 cell lines and 80 of 81 clinical cancer specimens (98.8%; 95% confidence interval, 96.4–100%) were genotyped accurately with the microarray, a rate better than that of direct DNA sequencing (38.9%) or SSCP (93.8%). Only one clinical specimen was misdiagnosed as homozygous for the wild-type allele. Densitometric analysis of SSCP bands indicated that the content of the mutant allele in the specimen was ∼16%. The PamChip microarray could detect mutant alleles representing more than 25% of the SSCP band proportions. Therefore, the limit for detection of mutant alleles by the PamChip microarray was estimated to be 16–25% of the total DNA.

Conclusions: The PamChip microarray is a novel three-dimensional microarray system and can be used to analyze K-ras mutations quickly and accurately. The mutation detection rate was nearly 100% and was similar to that of PCR-SSCP together with sequencing analysis, but the microarray analysis was faster and easier.
Netzwerkvisualisierung (Network Visualization)
Authors: Brandes Ulrik , Wagner Dorothea
Published: June 2004

Das Thema Netzwerkvisualisierung umfasst alle Aspekte der Darstellung relationaler Strukturen. Die automatische Erzeugung von Netzwerkvisualisierungen hat wichtige Anwendungen nicht nur innerhalb der Informatik, sondern generell in allen Bereichen, in denen graphische Datenanalyse oder visuelle Informationsvermittlung eine Rolle spielen. Als eigenständiges Forschungsgebiet der Informatik ist die Netzwerkvisualisierung — oft auch als Graphenzeichnen bezeichnet — seit etwa 10 Jahren etabliert. Dazu gehören neben Algorithmentheorie und Algorithmen Engineering insbesondere Fragestellungen aus Graphentheorie und Kombinatorik, Modellierungsfragen und die Entwicklung von Software-Systemen. Dieser Artikel gibt einen Überblick über die wichtigsten methodischen Errungenschaften des Gebiets.
Aktuelle Anwendungen der Wissenschaftlichen Visualisierung (Current Applications of Scientific Visualization)
Authors: Hege Hans-Christian
Published: June 2004

Die wissenschaftliche Visualisierung hat eine Reihe von effizienten und nützlichen Methoden entwickelt, die zunehmend Anwendung in den Naturwissenschaften, der Technik und der Medizin finden. Wesentlich für die praktische Anwendbarkeit von Visualisierungsverfahren sind perzeptuelle Qualität, Interaktivität, und anwendungsspezifische Orientierung. Wir geben einen Überblick über aktuelle Entwicklungen und künftige Herausforderungen aus Anwendungssicht.
Wissenschaftliche Visualisierung – Ausgewählte Forschungsprojekte (Scientific Visualization – Selected Research Projects)
Authors: Ertl Thomas , Keim Daniel
Published: June 2004

Die Hauptbeiträge dieser Ausgabe belegen eindrucksvoll den Stand der Forschung, den die wissenschaftliche Visualisierung inzwischen erreicht hat. Allerdings kann das große Spektrum der Anwendungen und Projekte der in der Visualisierung aktiven Forschungsgruppen im deutschsprachigen Raum auf diese Weise kaum angemessen beschrieben werden. Daher geben wir im Folgenden ausgewählten Projekten die Möglichkeit, das Bild von dieser noch jungen Disziplin der Informatik abzurunden.
Elektromagnetischer Sensor zur Detektion der Flüssigkeits- und Gasbewegung bei aufsteigenden Blasen in Flüssigmetall (Electromagnetic Sensor for the Detection of Liquid and Gas Movement Induced by Ascending Bubbles in Liquid Metal)
Authors: Kaiser Erwin
Published: June 2004

Die Bewegung von opaker, elektrisch leitender Flüssigkeit (hier Flüssigmetall), besonders in engen, stehenden Rohren mit Gasinjektion (z.B. airlift pumps), soll ohne in den Querschnitt ragende Sensoren gemessen werden. Untersucht wird eine elektromagnetische Geschwindigkeitsmessanordnung mit Wandelektroden in einer Quecksilbersäule mit Argonblasen. Aus Spannungsverlauf und injiziertem Gasvolumenstrom werden Richtung und Größe der Flüssigmetallbewegung sowie Blasenbewegung und -abmessung ermittelt.
Automatische Messung der Kontaktkraft von piezoelektrischen Biegewandlern (Automatic Measurement of the Contact Force of Piezoelectric Benders)
Authors: Ressing Michael , Kuhnen Klaus , Janocha Hartmut
Published: June 2004

Das hier vorgestellte automatische Messverfahren ermöglicht die Bestimmung der Kontaktkraft zwischen einem piezoelektrischen Biegewandler, der durch eine elektrische Gleichspannung ausgelenkt wird, und einem steifen Anschlag, der die Auslenkung begrenzt. Dazu wird eine Gegenkraft auf den Biegewandler ausgeübt und so lange kontinuierlich erhöht, bis dieser den Anschlag nicht mehr berührt. Der während dieses Vorgangs aufgezeichnete Kraft-Zeit-Verlauf weist charakteristische Merkmale auf, deren Auswertung die Bestimmung der gesuchten Kontaktkraft ermöglicht. Die Signalverarbeitung basiert auf einem nichtlinearen Signalmodell, dessen Parameter anhand einer unterlagerten quadratischen und einer überlagerten nichtlinearen Optimierung identifiziert werden.
Effect of Temperature on Clove Oil Anesthesia in Steelhead Fry
Authors: Woolsey J , Holcomb M , Ingermann R L
Published: June 2004

The effects of temperature (11, 15, and 20°C) on clove-oil-induced anesthesia in fry of steelhead Oncorhynchus mykiss (0.18 ± 0.01 g [mean ± SE]) were evaluated at 25, 50, and 100 mg clove oil/L. Induction time decreased significantly with increasing temperature and dose. Recovery time after removal from anesthesia decreased significantly with increasing temperature. Mortality at 24 h postanesthesia increased significantly with increasing temperature and dose. Although clove oil appears to be an effective general anesthetic for salmonid fry, the data indicate that care must be taken in determining the appropriate dose to minimize temperature-associated mortality.
A Compact Water-Heating System for Thermally Marking Salmon Otoliths
Authors: Mortensen Donald G , Wertheimer Alex C , Taylor Sidney G
Published: June 2004

We describe a compact water-heating system for thermally marking salmon otoliths during incubation. The system is portable and can be used to provide heated water for either streamside or instream incubators. The heating system consists of a small, propane-fired boiler and heat exchanger, a jet pump, a motorized set-point, a four-way mixing valve, and two circulating pumps. Warmed stream water exiting the heat exchanger is pumped to a head tank, mixed with ambient water to the desired temperature, and dispersed to the incubators, where some or all of the water can be recirculated or discarded. The mixing valve maintains a constant temperature in water flowing to the head tank based on a sensor feedback loop from the recovery tank. Using this system, we successfully marked approximately 800,000 pink salmon Oncorhynchus gorbuscha with no apparent adverse affects. Depending on incubation techniques, larger numbers of eggs or alevins could be marked.
Effects of Temperature and Size on Ammonia Excretion by Fasted Golden Shiners
Authors: Zhang Zhengzhong , Goodwin Andrew E , Pfeiffer Timothy J , Thomforde Hugh
Published: June 2004

The golden shiner Notemigonus crysoleucas is the major species of baitfish raised and sold in the United States. They are shipped in trucks from large farms to distributors up to 2,500 km distant. The costs associated with shipping could be greatly reduced if truck loading were increased, but higher densities of fish elevate ammonia concentrations to detrimental levels. In our work, we have simulated live hauling conditions to measure the ammonia excretion rates of golden shiners at 15, 20, and 25°C. The experiments were conducted for 24 h in three recirculating systems after fingerling golden shiners were fasted and acclimated for 2 d. The experiment was repeated four times using different lots and sizes of golden shiners. The results indicated that there were no significant differences in the hourly ammonia excretion rates (HER) between two lots of same-size golden shiners. The hourly ammonia excretion rates were inversely proportional to fish weight and increased with temperature. The average HER for all sizes of fish ranged from 2.9 to 7.4 g NH3-N/kg fish/h at 15°C, 5.2–11.2 g NH3-N/kg fish/h at 20°C, and 6.2–15.0 g NH3-N/kg fish/h at 25°C. The results of this study will be used to design ammonia control systems to safely increase fish density on commercial fish hauling trucks.
Ploidy of Backcross Hybrids of Largemouth Bass and Smallmouth Bass
Authors: Gomelsky Boris , Dabrowski Konrad , Garcia-Abiado Mary Ann , Stilwell William , Tidwell James H , Coyle Shawn D
Published: June 2004

Interspecies hybridization in fish may trigger the transformation of oogenesis in hybrid females, resulting in formation of eggs with unreduced diploid chromosome number. This phenomenon is revealed by the triploidy of backcross offspring obtained from crossing F1 hybrid females with males of either parental species. To determine whether the F1 hybrids of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu produce diploid eggs, we designed a study for evaluating the ploidy of backcross offspring (F1 hybrid females × largemouth bass males). Fish ploidy was determined by flow cytometry measurement of DNA content. The results of flow cytometry analysis showed that backcross hybrids had the same amount of DNA as largemouth bass and F1 hybrids, which suggests diploidy (2n) of backcross hybrids. This indicates that the F1 hybrid females between largemouth bass and smallmouth bass generate haploid eggs and do not experience the transformation of oogenesis that has been described in several other distant fish hybrids. Results of this study will be used to evaluate hybrids of largemouth bass and smallmouth bass as potential candidates for aquaculture.