bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and laboratory diagnosis of the metabolic syndrome
Authors: Olufadi R , Byrne C D
Published: May 2008

The epidemic of obesity is largely responsible for the high prevalence of metabolic syndrome in the developed world. Since 2001 with the development of the NCEP metabolic syndrome classification, simple pragmatic criteria have been available that can be applied in primary care across all continents to diagnose the syndrome. Although there is an ongoing debate about the level of thresholds that should be applied to individual features of the syndrome, it is likely that with further research a consensus will be reached in the near future. It is now clear that metabolic syndrome represents a condition of insulin resistance and ectopic fat accumulation associated with a proinflammatory and procoagulant phenotype. The syndrome is sometimes associated with other conditions such as non-alcoholic fatty liver disease (NAFLD), polycystic ovary syndrome, type 2 diabetes and cardiovascular disease. The purpose of this review is to discuss the clinical and laboratory diagnosis of the metabolic syndrome. The review discusses the various approaches to the investigation of people with the metabolic syndrome. Simple tools for clinical and laboratory diagnosis of metabolic syndrome are described. Some of the more complex biochemical tests that are now being applied in research to the diagnosis of associated conditions, such as NAFLD, are also described.
Molecular testing for somatic mutations in common cancers: the views of UK oncologists
Authors: Wordsworth S , Buchanan J , Papanicolas I , Taylor J , Frayling I , Tomlinson I
Published: May 2008

Background:

Somatic mutations are important determinants of cancer behaviour and response to therapy. However, molecular testing in this context has a relatively low profile within the clinical community, despite publicity surrounding targeted therapies such as Herceptin.

Aims:

As the testing process affects many stakeholders, especially oncologists, this paper examines current test request patterns and views of such testing.

Methods:

A postal questionnaire was mailed to 582 UK oncologists and haematologists, achieving a 20% response rate.

Results:

The survey revealed that immunohistochemistry and fluorescent in situ hybridisation are the most commonly requested tests (used by 70% and 55% of respondents, respectively), especially for breast cancer. Availability of suitable treatment options is the main factor influencing the decision to test (selected by 62% of respondents). Respondents were generally positive about future demand for immunohistochemistry, fluorescent in situ hybridisation, microarray analysis and DNA-based tests, but uncertain about the prospects for microsatellite instability and ploidy testing.

Conclusions:

Overall, respondents thought that somatic mutation testing could have a significant and positive effect on oncology and haematology departments and patient care, especially with better treatment and tumour classification. However, lack of supportive scientific evidence and funding were considered key barriers to widespread testing. Further research is clearly required on both the resource implications of this increase in demand and the best model of service delivery to ensure the most efficient use of health service resources.
Early life second-hand smoke exposure and serious infectious morbidity during the first 8 years: evidence from Hong Kong’s “Children of 1997” birth cohort
Authors: Kwok M K , Schooling C M , Ho L M , Leung S S L , Mak K H , McGhee S M , Lam T H , Leung G M
Published: May 2008

Background:

Second-hand smoke (SHS) exposure is a modifiable cause of ill health. Despite the smoking ban in public places introduced in Hong Kong in 2007, infants and children continue to be exposed within the home.

Aims:

To determine the critical windows of SHS exposure and the duration of its impact on serious infectious morbidity in the first 8 years of life.

Methods:

The Hong Kong “Children of 1997” birth cohort is a prospective, population-based study of 8327 children comprising 88% of all births in April and May 1997, of whom 7402 (89%) were followed up until their eighth birthday in 2005. We used multivariable Cox regression to assess the relation between postnatal SHS exposure and risk of first admission to public hospitals (together accounting for >95% total bed-days overall) for respiratory, other and all infections from birth to 8 years of age, for all individuals and for vulnerable subgroups.

Results:

Overall, household SHS exposure within 3 metres in early life was associated with a higher risk of admission for infectious illness up until 8 years of age (hazard ratio 1.14, 95% CI 1.00 to 1.31), after adjustment for sex, birthweight, gestational age, feeding method, maternal age, highest parental education and proxies of preferred service sector. The association was strongest in the first 6 months of life (HR 1.45, 95% CI 1.15 to 1.83). In vulnerable subgroups such as premature babies, the association held through to 8 years of age (HR 2.00, 95% CI 1.08 to 3.72). Infants exposed to SHS in the first 3 months of life were most vulnerable to infectious causes of hospitalisation.

Conclusion:

Household SHS exposure in early infancy increases severe infectious morbidity requiring hospital admission. Reducing SHS exposure in infants and particularly in more vulnerable infants will lower the bed-days burden due to infectious causes.
Univoltine and Semivoltine Life Histories inSenecella calanoides(Copepoda: Calanoida) and Their Relationship to Body Size
Authors: Carter J. C. H. , Dadswell M. J. , Goudie K.
Published: May 2008

Most populations of Senecella calanoides Juday in eastern Canada are univoltine. However, in Lake Mazinaw, southern Ontario, and probably in three additional lakes in western Quebec it has a 2-yr life history (semivoltine) with two fractions, different in age by 1 yr, developing together. The additional year of development in Mazinaw is spent almost entirely in the fourth and fifth copepodite instars. Slower development in semivoltine populations is tentatively attributed to colder waters resulting from extensive hypolimnia, with limited food as a possible secondary cause. Later copepodites of semivoltine populations were smaller than their univoltine counterparts, possibly because of poorer nutrition.
Three-Dimensional Prey Reaction Field of the Juvenile Coho Salmon (Oncorhynchus kisutch)
Authors: Dunbrack Robert L. , Dill Lawrence M.
Published: May 2008

Filmed observations of the feeding behaviour of juvenile coho salmon (Oncorhynchus kisutch) cruising in a large aquarium were used to determine the three-dimensional shape of their reaction field, and to estimate the cross-sectional area of the effective volume searched for prey (scanning area). Reaction distance was greatest above the horizontal visual plane and ahead of the transverse visual plane, and this corresponds to the feeding behaviour of fish observed in the wild. The scanning area for a given size of prey was obtained by plotting all captures as projections on the transverse plane. This distribution of points was then divided into a series of concentric bands characterized by prey attack probabilities, which were then used as weighting factors in the final calculation of the scanning area. Our results and techniques are discussed in relation to previous studies of fish reaction fields, and a simple method of estimating scanning area for salmonids is suggested.
Effect of Diet on the Immune Response of Rainbow Trout (Salmo gairdneri)
Authors: Blazer Vicki S. , Wolke Richard E.
Published: May 2008

To compare the effect of diet on the immune response of rainbow trout (Salmo gairdneri), we maintained fish on either a commercial feed or a laboratory prepared (control) diet for 12–16 wk before antigenic exposure. The immune response to two antigens, sheep red blood cells (SRBC) and Yersinia ruckeri, was assessed. Both T-cell (migration inhibition factor) and B-cell (plaque-forming cell) responses to SRBC were measured. The plaque-forming cell response and the humoral (serum antibody) responses to Y. ruckeri were assayed. In addition, the phagocytic ability of peritoneal macrophages was assessed as a nonspecific resistance factor. We found that fish maintained on the commercial diet had a significantly lower immune response when compared with fish fed the control diet, although all fish appeared healthy and suffered no mortalities throughout the experiment. We indicate the importance of considering the effects of diet on immunity and disease resistance in future feed formulations.
Effects of Inorganic Cations on Na+Adsorption to the Gill and Body Surface of Rainbow Trout,Oncorhynchus mykiss, in Dilute Solutions
Authors: Handy R. D. , Eddy F. B.
Published: May 2008

Using the shortest practical exposure time (15 s) to 0.2 mmol∙L−1NaCl solutions containing22Na, over 80% of the Na+taken up by rainbow trout, Oncorhynchus mykiss, was located on the gill or body surface (adsorption). Influx to the blood (absorption) was less than 20% of the total taken up, even though Na+entry into the blood was detected in less than 30 s. Sodium adsorption to the fish surface was strongly reduced by micromolar concentrations of Ca2+or by acid in the range pH 7–5. At higher NaCl concentrations (2 mmol∙L−1in the medium, Ca2+effects on adsorption were greatly attenuated. Aluminum had a negligible effect on adsorption at pH 4. It is concluded that adsorption has an important role in presenting Na+to the apical surface of gill ion transporting cells, since conditions which inhibit the branchial influx of Na+also reduce Na+adsorption. The results suggest that adsorption is controlled by ion exchange events at gill surface ligands, and by the effects of other cations on the mobility of Na+in the bulk water. Adsorption phenomena are likely to influence ionic regulation during normal fluctuations in environmental conditions.
Mechanisms of Impact of an introduced Crayfish (Orconectes rusticus) on Littoral Congeners, Snails, and Macrophytes
Authors: Olsen T. Mark , Lodge David M. , Capelli Gregory M. , Houlihan Robert J.
Published: May 2008

Since its introduction 30 yr ago, Orconectes rusticus has displaced O. propinquus and O. virilis and reduced macrophytes in several northern Wisconsin lakes. Since 1973, rate of displacement by O. rusticus varied among lakes, but relative abundance of O. rusticus increased in all nine lakes sampled in 1988 (eight of which were sampled in 1973 or 1975 and 1980). Using long-term field data and laboratory experiments, we explored mechanisms of differential impact of O. rusticus (relative to congeners) on benthic community structure. Displacement of O. propinquus (but not O. virilis) by O. rusticus increased mean crayfish size. Congener feeding preference did not differ among morphologically different macrophytes or between different-sized snails; however, weight-specific consumption and destruction rates did. Orconectes rusticus consumed more snails than its congeners and sublethally damaged more snails than O. virilis. Orconectes rusticus consumed more macrophyte biomass than O. propinquus; however, O. rusticus did not destroy (consumption plus fragmentation) more macrophyte biomass than its congeners. Changes in benthic community structure after displacement of congeners by O. rusticus may result from larger size (which probably lowers resource depression in the presence of size-selective fish predators) and greater weight-specific reductions of prey.
A Method for Estimating Spill Effectiveness for Passing Juvenile Salmon and Its Application at Lower Granite Dam on the Snake River
Authors: Wilson John W. , Giorgi Albert E. , Stuehrenberg Lowell C.
Published: May 2008

Juvenile salmonids migrating down the Snake and Columbia rivers in the northwestern United States pass each of the rivers' hydroelectric dams via either the powerhouse or the spillway. Spill effectiveness, the proportion of juveniles passing through the dam via the spillway, is important to fishery managers seeking to minimize the exposure of fish to turbines. We outline a method for estimating spill effectiveness and its sampling variance using a multinomial model with categories defined on the basis of information recovered from radio tagged fish. We applied this method to data from tagged chinook salmon (Oncorhynchus tshawytscha) juveniles released at Lower Granite Dam in 1985. For two release conditions, one with 20 and the other with 40% of the total water volume going through the spillway, the maximum likelihood estimates of spill effectiveness were 41 and 61%, respectively. Increasing the flow of water through spillways may therefore be a useful method of increasing spill passage of juvenile salmonids at Lower Granite Dam. Similar radio tag experiments and multinomial models could readily be devised to study spill effectiveness at hydroelectric projects with a wide variety of structural plans.
Some Aspects of Ascorbate Metabolism in Developing Embryos of the Brine Shrimp (Artemia salina)
Authors: Dabrowski Konrad
Published: May 2008

Cysts of the brine shrimp (Artemia salina) during various hydration states were analyzed for ascorbate concentration. At a state of cellular dehydration and metabolic arrest, ascorbate is stored in the form of stable ascorbic sulfate. Cysts from six populations in North America, France, Australia, and China differed considerably in ascorbic sulfate concentration (162.4–428.5 μg∙g dry matter−1, expressed as ascorbic acid). Embryos incubated in NaCl solution started to hydrolyze the stable form and released free ascorbic acid. Major transfer of the stable sulfated form to active ascorbic acid (on an equimolar basis) also took place at hatching. Activity of ascorbic sulfate sulfohydrolase was analyzed by two methods and peak activity after hatching corresponds to an increase of free ascorbic acid. However, decapsulation of cysts does not lead to ascorbic sulfate hydrolysis, and therefore raises the question of vitamin C availability for larval fish fed decapsulated Artemia.
Organochlorine Concentrations in the Plankton of Lakes in Southern Ontario and Their Relationship to Plankton Biomass
Authors: Taylor W. D. , Carey J. H. , Lean D. R. S. , McQueen D. J.
Published: May 2008

Hydrophobic organochlorine contaminants were surveyed in net plankton from 33 lakes in southern Ontario. Organochlorines were detected in all lakes. The relative concentrations of 12 common organochlorines were generally similar, suggesting that they derive from a common source, probably atmospheric transport. Variability in relative abundances of these contaminants increased with contaminant concentration, while contaminant concentration was related to plankton biomass, total phosphorus, and conductivity. Lakes with low plankton biomass had high organochlorine concentrations in that biomass, indicating that a large portion of the variation among lakes in the concentration of contaminants in plankton can be ascribed to variable planktonic biomass. This negative relationship with plankton biomass, or biomass dilution effect, was strongest for the more hydrophobic and refractory compounds.
Patterns and Limitations in Limnoplankton Size Spectra
Authors: Ahrens Martin A. , Peters Robert H.
Published: May 2008

The hypothesis that biomass is uniformly distributed over logarithmic size classes was evaluated with plankton samples from 15 temperate lake sites in southern Quebec. Over the size range from 0.2 to 1600 μm equivalent spherical diameter (ESD), biomass tended to increase between logarithmic size classes at a median rate of 7%, and numerical abundance declined strongly with increasing size. The slope of the normalized biomass spectrum (reflecting overall trends in the distribution) becomes significantly steeper as total phosphorus decreases and total biomass declines. Hence, more oligotrophic systems have a more uniform biomass distribution and proportionately more small organisms. Over the observed size range, most samples were dominated by a phytoplankton mode between 20 and 50 μm ESD. Because of this dominance and because of the variability of the samples, most sample distributions could not be shown to differ significantly from unimodal lognormal distributions. Efforts to fit bimodal and trimodal distributions met with limited success, likely because only 39 size classes could be used. Simple mathematical descriptors of size spectra are insensitive to substantial departures from both linear and lognormal models, and therefore, variaion in the parameters of such descriptions are ineffective correlates of departures from average patterns.
Effects of Long-Term Preexposure to Sublethal Concentrations of Acid and Aluminum on the Ventilatory Response to Aluminum Challenge in Brook Trout (Salvelinus fontinalis)
Authors: Walker R. L. , Wood C. M. , Bergman H. L.
Published: May 2008

Adult brook trout (Salvelinus fontinalis; 200–300 g) were preexposed for 10 wk to 75 μg Al3+∙L−1, pH = 5.2, in soft water (25 μequiv Ca2+∙L−1) and controls to the same conditions without Al3+. When challenged with a lethal dose of Al3+(333 μg∙L−1) at the same pH (5.2) and Ca2+(25 μequiv∙L−1), the control fish demonstrated a twofold increase in ventilation volume and ventilatory stroke volume within the first two hours, an increase in [Formula: see text], and a decrease in pHa and hemoglobin O2saturation. These effects were not seen in the group chronically preexposed to sublethal Al, indicating that some acclimation had occurred. Although the prechallenge [Formula: see text] and [Formula: see text] were the same in the two groups, the arterial pH, plasma [HCO3−], and hemoglobin O2saturation of the Al-preexposed fish were significantly below those of the control fish, suggesting that the acclimation was achieved at some cost. Possible mechanisms are discussed.
Nature and Time Course of Acclimation to Aluminum in Juvenile Brook Trout (Salvelinus fontinalis). II. Gill Histology
Authors: Mueller M. E. , Sanchez D. A. , Bergman H. L. , McDonald D. G. , Rhem R. G. , Wood C. M.
Published: May 2008

Gill samples from juvenile brook trout (Salvelinus fontinalis) acclimated to low-level aluminum at pH 5.2 showed severe damage by day 4, with necrosis and fusion of secondary lamellae and hyperplasia and hypertrophy of mucous cells. Over the following 20 d, there was a continual process of repair with proliferation and hypertrophy of mucous cells. Qualitative analysis of gill samples plus physiology and mortality data collected in a companion study indicated progressive development (by day 10 onward) of increasing acclimation to Al. Quantitative analysis of gill samples on day 13 showed that mucous cell volume density had tripled and mucous cell area had doubled in Al-exposed fish compared with control fish. A lamellar fusion index showed evidence of fusion in Al-exposed fish by day 4 with recovery to nearly control levels by day 13. Physiological disturbances appear to be directly related to the histological changes observed in the gill epithelium. At the cellular level, changes in either mucous cell production and secretion or changes in mucus chemistry contribute, in part, to acclimation to Al.
TOPOLOGICAL STRUCTURE OF THE MANY VORTICES SOLUTION IN JACKIW–PI MODEL
Authors: LEE XI-GUO , LIU ZI-YU , LI YONG-QING , ZHANG PENG-MING
Published: May 2008

By using the gauge potential decomposition, we discuss the self-dual equation and its solution in Jackiw–Pi model. We obtain a new concrete self-dual equation and find relationship between Chern–Simons vortices solution and topological number which is determined by Hopf indices and Brouwer degrees of Ψ-mapping. To show the meaning of topological number we give several figures with different topological numbers. In order to investigate the topological properties of many vortices, we use five parameters (two positions, one scale, one phase per vortex and one charge of each vortex) to describe each vortex in many vortices solutions in Jackiw–Pi model. For many vortices, we give three figures with different topological numbers to show the effect of the charge on the many vortices solutions. We also study the quantization of flux of those vortices related to the topological numbers in this case.
EXTENDED BRS SYMMETRY IN TOPOLOGICAL FIELD THEORIES
Authors: VALTANCOLI P.
Published: May 2008

A class of topological field theories like the BF model and Chern–Simons theory, when quantized in the Landau gauge, enjoys the property of invariance under a vector supersymmetry, which is responsible for their finiteness. We introduce a new type of gauge fixing which makes these theories invariant under an extended BRS symmetry, containing a new type of field, the ghost of diffeomorphisms. The presence of such an extension is naturally related to the vector supersymmetry discussed before.
COSMOLOGY WITH PSEUDO-NAMBU–GOLDSTONE BOSONS
Authors: SORBO LORENZO
Published: May 2008

Pseudo-Nambu–Goldstone bosons (pNGBs) are simple and elegant candidates for radiatively stable models of quintessence and inflation. In this brief review, we first examine the observational status of pNGB-driven quintessence and inflation. We then discuss the construction of theoretically as well as observationally viable models of cosmological pNGBs. Special emphasis will be given to the constructions of models compatible with the requirements from String Theory.
SELF-ORGANIZATION AND NONEQUILIBRIUM STRUCTURES IN THE PHASE SPACE
Authors: NOVIKOV V. , KRUCHININ S. , BOGOLUBOV N. N. , ADAMENKO S.
Published: May 2008

We consider the possibilities of the formation of quasistationary distributions of particles over energy with power asymptotics in nonequilibrium systems and dynamical systems with couplings. It is shown that the Tsallis distribution is related to the exact solutions of a kinetic equation of the Boltzmann type and those of covariant kinetic equations of the Vlasov nonlocal statistical mechanics.

We have studied the connection of the power-like solutions of kinetic equations with the eigenfunctions of fractional integro-differential operators and Jackson operators within quantum analysis, and that of nonextensiveness parameters in the framework of the Tsallis thermostatics, with flows in the phase space. It is shown that the processes running in a nonequilibrium nonconservative medium can be described by the solutions of the equation with fractional derivatives or Jackson derivatives for oscillations.
QoS-Aware service management for component-based distributed applications
Authors: Jin Jingwen , Nahrstedt Klara
Published: May 2008

Component-based software development has evolved from a tightly coupled style to a loosely coupled style in the recent few years. The paradigm shift will eventually allow heterogeneous systems to interoperate in open networks such as the Internet and will make software development more of a management task than a development task. Envisioning that future applications may comprise dynamically aggregated component services possibly distributed widely, we develop a Quality of Service (QoS)-aware service management framework in the middleware layer to make the component services infrastructure transparent to the applications. Specifically, we manage services not only as individuals, but more importantly as meaningful aggregated entities based on the logical compositional needs coming from the applications, by composing services properly according to QoS requirements at application setup time, and performing continuous maintenance at application runtime seamlessly. Our service management framework is scalable in two dimensions: network size and application's client population size. Specifically, the framework employs a decentralized management solution that scales to large network size, and explores resource sharing in one-to-many group-based applications by means of multicasting mechanisms. Moreover, it incorporates local adaptation operations and distributed failure detection, reporting, and recovery mechanisms to deal with runtime resource fluctuations and failures.
Grounding the Scholarship of Teaching and Learning in Practice
Authors: Tenenberg Josh , Mccartney Robert
Published: May 2008

We invite submissions to ACM/JERIC from teaching practitioners who are our readers. Grounding these submissions in the lived practice of teaching; using data that is already collected to assess student learning; and reporting the data collection, analysis, and context of use accurately and honestly are key aspects for taking a scholarly approach to teaching and learning. We hope to see more such scholarly inquiries by computing educators in the pages of future issues.
Empirical Foundation of Central Concepts for Computer Science Education
Authors: Zendler Andreas , Spannagel Christian
Published: May 2008

The design of computer science curricula should rely on central concepts of the discipline rather than on technical short-term developments. Several authors have proposed lists of basic concepts or fundamental ideas in the past. However, these catalogs were based on subjective decisions without any empirical support. This article describes the empirical determination of central concepts for computer science education. Experts of computer science rated 49 concepts regarding four criteria. The cluster analysis of the data revealed the following central concepts:problem, data, computer, test, algorithm, process, system, information, language, communication, software, program, computation, structure, andmodel.
A survey on querying encrypted XML documents for databases as a service
Authors: Ünay Ozan , Gündem Taflan I.
Published: May 2008

"Database as a service" paradigm has gained a lot of interest in recent years. This has raised questions about the security of data in the servers. Firms outsourcing their XML databases to untrusted parties started to look for new ways to securely store data and efficiently query them. In this paper, encrypted XML documents, their crypto index structures and query processing using these structures are investigated. A comparison of various algorithms in the literature is given.
BP-Mon
Authors: Beeri Catriel , Eyal Anat , Milo Tova , Pilberg Alon
Published: May 2008

A Business Process (BP for short) consists of some business activities undertaken by one or more organizations in pursuit of some particular goal. It often interacts with other BPs of the same or other organizations and the software implementing it is rather complex. Two complementary instruments facilitate the design, development, and management of this complex software. The first is the use of
standards
. In particular, the recent BPEL standard (Business Process Execution Language [5]) provides an XML-based language to describe the operational logic and execution flow of the BP, as well as the interfaces it exposes to other BPs. A BP specification written in BPEL can be automatically compiled into an actual code that implements the BP, and can be executed on a BPEL server. The second instrument is the use of
supporting BP management tools
for (1) designing the BP BPEL specifications, (2) analyzing the design, (3) monitoring the BPs at run time, and (4) analyzing, posteriorly, the process execution traces (logs). Together they provide an essential infrastructure for companies to design business processes, optimize them, reduce operational costs, and ultimately increase competitiveness.
Report on the Principles of Provenance Workshop
Authors: Cheney James , Buneman Peter , Ludäscher Bertram
Published: May 2008

Provenance, or records of the origin, context, custody, derivation or other historical information about a (digital) object, has recently become an important research topic in a number of areas, particularly databases. However, there has been little interaction between researchers across subdisciplines of computer science working on related problems. This article reports on a workshop on Principles of Provenance held in Edinburgh, Scotland in November 2007, which facilitated interaction among researchers working on provenance in databases, security, information retrieval, Semantic Web, and software engineering settings, as well as developers and database administrators who are currently working with provenance in practice, or foresee the need to do so in the near future.
Loss of resistin ameliorates hyperlipidemia and hepatic steatosis in leptin-deficient mice
Authors: Singhal Neel S. , Patel Rajesh T. , Qi Yong , Lee Yun-Sik , Ahima Rexford S.
Published: May 2008

Resistin has been linked to components of the metabolic syndrome, including obesity, insulin resistance, and hyperlipidemia. We hypothesized that resistin deficiency would reverse hyperlipidemia in genetic obesity. C57Bl/6J mice lacking resistin [resistin knockout (RKO)] had similar body weight and fat as wild-type mice when fed standard rodent chow or a high-fat diet. Nonetheless, hepatic steatosis, serum cholesterol, and very low-density lipoprotein (VLDL) secretion were decreased in diet-induced obese RKO mice. Resistin deficiency exacerbated obesity in ob/ob mice, but hepatic steatosis was drastically attenuated. Moreover, the levels of triglycerides, cholesterol, insulin, and glucose were reduced in ob/ob-RKO mice. The antisteatotic effect of resistin deficiency was related to reductions in the expression of genes involved in hepatic lipogenesis and VLDL export. Together, these results demonstrate a crucial role of resistin in promoting hepatic steatosis and hyperlipidemia in obese mice.
The lowering of hepatic fatty acid uptake improves liver function and insulin sensitivity without affecting hepatic fat content in humans
Authors: Rigazio Sara , Lehto Hanna-Riikka , Tuunanen Helena , Någren Kjell , Kankaanpaa Mikko , Simi Claudia , Borra Ronald , Naum Alexandru G. , Parkkola Riitta , Knuuti Juhani , Nuutila Pirjo , Iozzo Patricia
Published: May 2008

Lipolysis may regulate liver free fatty acid (FFA) uptake and triglyceride accumulation; both are potential causes of insulin resistance and liver damage. We evaluated whether 1) systemic FFA release is the major determinant of liver FFA uptake in fasting humans in vivo and 2) the beneficial metabolic effects of FFA lowering can be explained by a reduction in liver triglyceride content. Sixteen healthy subjects were subdivided in two groups of similar characteristics to undergo positron emission tomography with [11C]acetate and [11C]palmitate to quantify liver FFA metabolism ( n = 8), or magnetic resonance spectroscopy (MRS) to measure hepatic fat content ( n = 8), before and after the acute lowering of circulating FFAs by using the antilipolytic agent acipimox. MRS was again repeated after a 1-wk treatment period. Acipimox suppressed FFA levels while stimulating hepatic fractional extraction of FFAs ( P < 0.05). As a result, fasting liver FFA uptake was decreased by 79% ( P = 0.0002) in tight association with lipolysis ( r = 0.996, P < 0.0001). The 1-wk treatment induced a significant improvement in systemic (+30%) and liver (+70%) insulin sensitivity ( P < 0.05) and decreased circulating triglycerides (−20%, P = 0.06) and liver enzymes (ALT −20%, P = 0.03). No change in liver fat content was observed after either acute or sustained FFA suppression. We conclude that acute and sustained inhibitions of lipolysis and liver FFA uptake fail to deplete liver fat in healthy human subjects. Liver FFA uptake was decreased in proportion to FFA delivery. As a consequence, liver and systemic insulin sensitivity were improved, together with liver function, independently of changes in hepatic triglyceride accumulation.
Sodium arsenite induces orphan nuclear receptor SHP gene expression via AMP-activated protein kinase to inhibit gluconeogenic enzyme gene expression
Authors: Chanda Dipanjan , Kim Sung-Jin , Lee In-Kyu , Shong Minho , Choi Hueng-Sik
Published: May 2008

Sodium arsenite has been demonstrated to alter the expression of genes associated with glucose homeostasis in tissues involved in the pathogenesis of type 2 diabetes; however, the underlying molecular mechanism has not been fully elucidated yet. In this study, we report that the sodium arsenite-induced gene expression of the small heterodimer partner (SHP; NR0B2), an atypical orphan nuclear receptor, regulates the expression of hepatic gluconeogenic genes. Sodium arsenite augments hepatic SHP mRNA levels in an AMP-activated protein kinase (AMPK)-dependent manner. Sodium arsenite activated AMPK and was shown to perturb cellular ATP levels. The arsenite-induced SHP mRNA level was blocked by adenoviral overexpression of dominant negative AMPK (Ad-dnAMPKα) or by the AMPK inhibitor compound C in hepatic cell lines. We demonstrated the dose-dependent induction of SHP mRNA levels by sodium arsenite and repressed the forskolin/dexamethasone-induced gene expression of the key hepatic gluconeogenic genes phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase). Ad-dnAMPKα blocked the repressive effects of arsenite-induced SHP on PEPCK and G6Pase. Sodium arsenite inhibited the promoter activity of PEPCK and G6Pase, and this repression was abolished by small interfering (si)RNA SHP treatments. The knockdown of SHP expression by oligonucleotide siRNA SHP or adenoviral siRNA SHP released the sodium arsenite-mediated repression of forskolin/dexamethasone-stimulated PEPCK and G6Pase gene expression in a variety of hepatic cell lines. Results from our study suggest that sodium arsenite induces SHP via AMPK to inhibit the expression of hepatic gluconeogenic genes and also provide us with a novel molecular mechanism of arsenite-mediated regulation of hepatic glucose homeostasis.
Impaired episodic LH secretion in female mice with GFP in GnRH neurons
Authors: Suter K. J. , O'Farrell L.
Published: May 2008

The ability to assess the activity of gonadotropin-releasing hormone (GnRH) neurons has been greatly enhanced by transgenic animal models with targeted expression of green fluorescent protein (GFP). However, it has yet to be demonstrated that the GnRH system continues to exhibit a full range of normal physiological functions in the presence of such genetic manipulation. Accordingly, we have used repetitive blood sampling via indwelling venous catheters to define LH secretory patterns in normal and transgenic mice. Transgenic females proved to be reproductively competent as defined by fecundity, appropriate cyclic changes in vaginal cytology in intact adult females, and spontaneous LH surges as well as surges in response to steroid or mating stimuli. The expression of c- fos following such steroid treatment and mating in ovariectomized transgenics was similar to the expression previously reported in nontransgenic mice. Likewise, the percentage of retrogradely labeled GnRH neurons was similar to that reported in nontransgenic mice. However, episodic LH secretion, an index of GnRH pulse generator activity, was dramatically compromised in ovariectomized female transgenics compared with C57BL6 controls of both sexes and castrated transgenic males. Taken together, these findings suggest that the GnRH pulse generator is selectively impaired in ovariectomized females in which GnRH neurons express GFP.
A Biophysical Model of Synaptic Plasticity and Metaplasticity Can Account for the Dynamics of the Backward Shift of Hippocampal Place Fields
Authors: Yu Xintian , Shouval Harel Z. , Knierim James J.
Published: May 2008

Hippocampal place cells in the rat undergo experience-dependent changes when the rat runs stereotyped routes. One such change, the backward shift of the place field center of mass, has been linked by previous modeling efforts to spike-timing–dependent plasticity (STDP). However, these models did not account for the termination of the place field shift and they were based on an abstract implementation of STDP that ignores many of the features found in cortical plasticity. Here, instead of the abstract STDP model, we use a calcium-dependent plasticity (CaDP) learning rule that can account for many of the observed properties of cortical plasticity. We use the CaDP learning rule in combination with a model of metaplasticity to simulate place field dynamics. Without any major changes to the parameters of the original model, the present simulations account both for the initial rapid place field shift and for the subsequent slowing down of this shift. These results suggest that the CaDP model captures the essence of a general cortical mechanism of synaptic plasticity, which may underlie numerous forms of synaptic plasticity observed both in vivo and in vitro.
Structural analysis of ZnO thin films obtained by d.c. sputtering and electron beam evaporation
Authors: Sabino M. E. L. , Oliveira D. M. , Falcão V. D. , Bernardes-Silva A. C. , Branco J. R. T.
Published: May 2008

ZnO thin films were produced by argon plasma assisted electron beam vacuum evaporation and d.c. magnetron sputtering deposition techniques. ZnO films are used in solar cells as transparent contact in heterojunction cells, and can be deposited on a variety of substrates by different techniques, including electron beam deposition and sputtering and laser ablation. ZnO thin films were prepared for photovoltaic applications and the structural properties were studied. The results showed that the sputtering and the vacuum evaporation techniques resulted, respectively, in a textured ZnO and ZnO plus Zn mixed phases. The annealing of the vacuum evaporation ZnO films resulted in films with high crystallinity.
Crystal structure refinement of Co-doped lanthanum chromites
Authors: Corrêa H. P. S. , Paiva-Santos C. O. , Setz L. F. , Martinez L. G. , Mello-Castanho S. R. H. , Orlando M. T. D.
Published: May 2008

Results of crystal structure refinements and phase quantification for samples of Co-doped lanthanum chromites with nominal composition LaCr1−xCoxO3, for x=0.00, 0.10, 0.20, and 0.30, prepared by combustion synthesis are presented. The resulting powders were characterized by scanning electron microscopy and X-ray diffraction (XRD). The XRD patterns were obtained with Cu Kα radiation for non-doped lanthanum chromite sample and additionally with Cr Kα radiation for Co-doped lanthanum chromites samples, in order to enhance the signal from scattering. Rietveld analysis of XRD data showed that the studied samples presented the lanthanum chromite with an orthorhombic structure (Pnma), except for the composition with x=0.30, in which the space group was found to be R3c.
Crystal structure and local order of nanocrystalline zirconia-based solid solutions
Authors: Fábregas I. O. , Lamas D. G. , Acuña L. M. , Walsöe de Reca N. E. , Craievich A. F. , Fantini M. C. A. , Prado R. J.
Published: May 2008

Crystal and local structures (long- and short-range order, respectively) of four nanocrystalline zirconia-based solid solutions—ZrO2-6 and 16 mol % CaO and ZrO2-2.8 and 12 mol % Y2O3—synthesized by a pH-controlled nitrate-glycine gel-combustion process were studied. These materials were characterized by synchrotron X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS) spectroscopy. Our XRD results indicate that the solid solution with low CaO and Y2O3 contents (6 and 2.8 mol %, respectively) exhibit a tetragonal crystallographic lattice, and those with higher CaO and Y2O3 contents (16 and 12 mol %, respectively) have a cubic lattice. Moreover, our EXAFS study demonstrates that the tetragonal-to-cubic phase transitions, for increasing CaO and Y2O3 contents, are both related to variations in the local symmetry of the Zr–O first neighbor coordination sphere.
Real-space strain mapping of SOI features using microbeam X-ray diffraction
Authors: Murray Conal E. , Polvino S. M. , Noyan I. C. , Lai B. , Cai Z.
Published: May 2008

Synchrotron-based X-ray microbeam measurements were performed on silicon-on-insulator (SOI) features strained by adjacent shallow-trench isolation (STI). Strain engineering in microelectronic technology represents an important aspect of the enhancement in complementary metal-oxide semiconductor device performance. Because of the complexity of the composite geometry associated with microelectronic circuitry, characterization of the strained Si devices at a submicron resolution is necessary to verify the expected strain distributions. The interaction region of the SOI strain extended the SOI film thickness from the STI edge at least 25 times. Regions of 65-nm-thick SOI less than 3 μm wide exhibited an overlap in the strain fields because of the surrounding STI. Microbeam mapping of arrays containing submicron SOI features and embedded STI structures revealed the largest out-of-plane strains because of the close proximity of superimposed strain distributions induced by the STI.
Flexible filamentous virus structures from fiber diffraction
Authors: Stubbs Gerald , Kendall Amy , McDonald Michele , Bian Wen , Bowles Timothy , Baumgarten Sarah , McCullough Ian , Shi Jian , Stewart Phoebe , Bullitt Esther , Gore David , Ghabrial Said
Published: May 2008

Fiber diffraction data have been obtained from Narcissus mosaic virus, a potexvirus from the family Flexiviridae, and soybean mosaic virus (SMV), a potyvirus from the family Potyviridae. Analysis of the data in conjunction with cryo-electron microscopy data allowed us to determine the symmetry of the viruses and to make reconstructions of SMV at 19 Å resolution and of another potexvirus, papaya mosaic virus, at 18 Å resolution. These data include the first well-ordered data ever obtained for the potyviruses and the best-ordered data from the potexviruses, and offer the promise of eventual high resolution structure determinations.
Rhombohedral-cubic phase transition characterization of (Pb,Ge)Te using high-temperature XRD
Authors: Sariel J. , Dahan I. , Gelbstein Y.
Published: May 2008

Rhombohedral-cubic transformation in Bi2Te3 doped-Pb1−xGexTe alloys is presented. Samples of Bi2Te3 doped Pb1−xGexTe were prepared by powder metallurgy approach. These powder samples were examined by high-temperature X-ray diffraction (XRD) and scanning electron microscopy/energy dispersive spectroscopy. A bulk (pressed powder) cylindrical specimen was used for dilatometery characterizations. According to the XRD examinations it seems that upon increasing the temperatures a continuous transformation occurs from the rhombohedral to the cubic phase, accompanied by the formation of a small amount of the phase Ge0.74Pb3.26Te4.
Monte Carlo simulation of projections in computed tomography
Authors: Chyba B. , Mantler M. , Reiter M.
Published: May 2008

Results from Monte Carlo simulations of two-dimensional projections for a simple real sample (an aluminium cube with a cylindrical hole filled by air or steel) in a realistic experimental environment are presented. A meaningful comparison with measurements was therefore possible. Coherent and incoherent scattering as well as excitation of fluorescent radiation are accounted for; multiple sequences of these interactions are followed up to a selectable order. Such simulations are important aids to modern metrological applications of computed tomography where the dimensional accuracy of hidden or inaccessible components of work pieces is determined. The complex process requires a high level of optimization of the instrumental parameters for each sample type whereby the accurate simulation of the physical interactions between X-rays and the sample material is a supplement and alternative to time consuming measurements.
Decorin-Induced Growth Inhibition Is Overcome through Protracted Expression and Activation of Epidermal Growth Factor Receptors in Osteosarcoma Cells
Authors: Zafiropoulos Alexandros , Nikitovic Dragana , Katonis Pavlos , Tsatsakis Aristidis , Karamanos Nikos K. , Tzanakakis George N.
Published: May 2008

Decorin is an established natural oncosuppressive factor whose action is being studied in detail. Recently, decorin gene therapy formulations using adenoviral vectors have been shown in several animal models with very promising results. The present study describes the first exception to the established oncosuppression model using human osteosarcoma cells. MG-63 osteosarcoma cells were found to constitutively produce decorin, and furthermore, to be resistant to decorin-induced growth arrest. On the contrary, decorin seemed to be beneficial to osteosarcoma cells because it was necessary for MG-63 cell migration and acted as a mediator, counteracting the transforming growth factor-β2–induced cytostatic function. Efforts to determine how MG-63 cells could overcome the decorin-induced cytostatic effect established that decorin in MG-63 cells does not induce p21 expression nor does it cause protracted retraction and inactivation of the epidermal growth factor receptor. Conversely, epidermal growth factor receptor seemed to be overexpressed and continuously phosphorylated. In view of the proposed design of decorin-based anticancer therapeutic strategies, our study provides new data on pathways that cancer cells might employ to overcome the established decorin-induced growth suppression. (Mol Cancer Res 2008;6(5):785–94)
Neutral Sphingomyelinase-3 Is a DNA Damage and Nongenotoxic Stress-Regulated Gene That Is Deregulated in Human Malignancies
Authors: Corcoran Chad A. , He Qin , Ponnusamy Suriyan , Ogretmen Besim , Huang Ying , Sheikh M. Saeed
Published: May 2008

In this study, we report the characterization of a novel genotoxic and nongenotoxic stress-regulated gene that we had previously named as SKNY. Our results indicate that SKNY encodes the recently identified neutral sphingomyelinase-3 (nSMase3; hereafter SKNY is referred to as nSMase3). Examination of nSMase3 subcellular distribution reveals nSMase3 to localize to the endoplasmic reticulum (ER), and deletion of a COOH-terminal region containing its putative transmembrane domain and ER targeting signal partly alters its compartmentalization to the ER. Treatment with genotoxic Adriamycin and nongenotoxic tumor necrosis factor-α up-regulates endogenous nSMase3 expression, albeit with different kinetics. Tumor necrosis factor-α up-regulates nSMase3 expression within 2 h that lasts beyond 24 h and declines to control levels by 36 h. Adriamycin up-regulation of nSMase3 is transient, occurs within 30 min, and declines to control levels by 120 min. Prolonged treatment with Adriamycin by 24 h and beyond, however, causes a down-regulation in nSMase3 expression. Activation of wild-type p53 also down-regulates nSMase3 expression, suggesting that DNA damage-mediated nSMase3 down-regulation seems to occur partly through the tumor suppressor p53. Overexpression of exogenous nSMase3 sensitizes cells to Adriamycin-induced cell killing, a finding consistent with the proposed proapoptotic role of nSMase enzymes and nSMase-generated ceramide. We further investigated nSMase3 expression in various human malignancies and found its expression to be deregulated in several types of primary tumors when compared with their matching normal tissues. Collectively, our results have identified nSMase3 to be an important molecule that is linked to tumorigenesis and cellular stress response. (Mol Cancer Res 2008;6(5):795–807)