bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent advances in imaging epilepsy
Authors: Craven Ian , Kotsarini Christina , Hoggard Nigel
Published: August 2010

Around 30 000 people are diagnosed with epilepsy every year in the UK. While many of these respond well to antiepileptic drugs, 20–30% have seizures that are resistant to best medical treatment. For these patients it is important to identify any structural abnormalities responsible for generating seizure activity that may be amenable to surgical resection. There are many imaging modalities available to investigate epilepsy including computed tomography (CT), nuclear medicine and magnetic resonance imaging (MRI). Additional techniques are available in specific circumstances including single positron emission CT, diffusion imaging, MR spectroscopy, perfusion imaging and functional MRI. Clearly with so many options, a targeted approach is required to reach a diagnosis efficiently. In this article, each modality is discussed along with the imaging options for the common causes of focal seizure activity.
Aquatic community metabolism response to municipal effluent inputs in rivers quantified using diel δ18O values of dissolved oxygen
Authors: Wassenaar L. I. , Venkiteswaran J. J. , Schiff S. L. , Koehler G.
Published: August 2010

The spatial footprint over which municipal wastewater effluents cause changes to aquatic community structure and metabolism is key information required for the management of discharges into rivers. Longitudinal studies were undertaken on the Bow and South Saskatchewan rivers, Canada, to assess a new isotopic and modelling approach that combined O2and δ18O-O2diel (24 h) response curves to quantify changes in integrated community aquatic metabolism as a result of point-source wastewater inputs. Diel samplings were conducted over four seasons along 50 km transects at Calgary (Bow River) and Saskatoon (South Saskatchewan River). Diel O2and δ18O-O2cycles grew in magnitude downstream of effluent inputs in all seasons compared with upstream control sites. δ18O-O2depletions clearly revealed the stimulating effect of effluent on aquatic photosynthesis. Diel isotopic mass balance modelling showed community metabolic responses to effluent inputs were most pronounced in the spring and summer when photosynthesis and respiration rates were about two- to three-fold higher than at upstream control sites. Our findings revealed that sewage treatment plant nutrient additions resulted in an enhanced metabolic footprint that extended beyond 50 km downstream.
Spatiotemporal patterns in migration timing of coho salmon (Oncorhynchus kisutch) smolts in North America
Authors: Spence Brian C. , Hall James D.
Published: August 2010

The timing of ocean entry by salmon smolts is presumed adaptive to maximize survival during this critical life transition. We analyzed the peak timing, duration, and interannual variation in timing of smolt migrations for 53 coho salmon ( Oncorhynchus kisutch ) populations from central California to Kodiak Island, Alaska. The objective was to examine potential influences of both local watershed characteristics and larger-scale processes in the marine environment on smolt migration patterns. Multivariate analyses demonstrated a strong latitudinal gradient in migration patterns with trends toward later, shorter, and more predictable migrations with increasing latitude. Cluster analysis performed on migration descriptors indicated three major population groupings that coincide with major coastal oceanic regions in the northeast Pacific: a northern group from Kodiak Island to the Queen Charlotte Islands, British Columbia, a central group from the Queen Charlotte Islands south to the Columbia River, and a southern group from the Columbia River southward. These regional patterns transcended local variability associated with watershed characteristics and trap location, suggesting that the patterns reflect adaptation to differences in timing and relative predictability of favorable conditions in the marine environments that smolts enter.
Reproductive interactions between fugitive farmed and wild Atlantic cod (Gadus morhua) in the field
Authors: Meager Justin J. , Skjæraasen Jon Egil , Fernö Anders , Løkkeborg Svein
Published: August 2010

Atlantic cod ( Gadus morhua ) are being increasingly farmed in net pens adjacent to coastal populations that are currently at historic lows. One concern is that farmed escapees enter local spawning shoals and mate with wild cod. We tested for the potential of escaped farmed cod to interact and hybridize with wild fish by examining the spatial dynamics of, and associations between, fish tagged with ultrasonic transmitters. Based on these data, we also investigated the basic mating system of cod in the field. The spawning ground was best described as a lekking arena. Wild males aggregated near the seafloor and associations between individuals were frequent. Wild females had a pelagic and dispersed distribution and rarely associated with each other. Associations between individual wild males and females were also infrequent. Farmed males rarely associated with wild fish and had core usage areas above the wild males, suggesting that they were not admitted into the spawning arena. Farmed females were over the spawning arena more frequently than wild females and often associated with wild males at the depth of the spawning arena, indicating potential mating with wild males and the possibility of courtship interference. Hence, hybridization between escaped farmed and wild cod is likely.
Incorporating lakes within the river discontinuum: longitudinal changes in ecological characteristics in stream–lake networks
Authors: Jones Nicholas E.
Published: August 2010

Lakes and rivers are intimately connected in an alternating series of lentic and lotic reaches in many regions. The study of lakes and their outlets in hierarchical and branching river networks has not gained the attention of stream ecologists, and little effort has been focused on synthesizing the ecology of lake–stream interactions within a drainage network. Rapid and predictable changes in the ecological characteristics of streams occur at the interface with lakes. The influence that a lake might have on a stream is dependent on its position within the stream, stream type and size, lake size and shape, and the inlet and outlet positions. Little is known about the influences of multiple lakes within stream–lake networks and how these influences are determined by network shape and pattern. Fruitful collaborations and novel insights will come from the combined efforts of limnologists, stream ecologists, and landscape ecologists. Geographic information systems and network analyses will play an important role in summarizing aquatic landscape characteristics and creating a predictive science of aquatic networks. Lakes need to be more explicitly incorporated into ecological concepts in stream ecology, and reciprocally, streams need to be incorporated into ecological concepts involving lakes for the successful management and conservation of our aquatic resources.
Sex differences in linear and nonlinear heart rate variability during early recovery from supramaximal exercise
Authors: Mendonca Goncalo V. , Heffernan Kevin S. , Rossow Lindy , Guerra Myriam , Pereira Fernando D. , Fernhall Bo
Published: August 2010

Women demonstrate greater RR interval variability than men of similar age. Enhanced parasympathetic input into cardiac regulation appears to be not only greater in women, but also protective during periods of cardiac stress. Even though women may have a more favorable autonomic profile after exercise, little research has been conducted on this issue. This study was designed to examine the cardiac autonomic response, in both male and female participants, during the early recovery from supramaximal exercise. Twenty-five individuals, aged 20 to 33 years (13 males and 12 females), performed a 30-s Wingate test. Beat-to-beat RR series were recorded before and 5 min after exercise, with the participants in the supine position and under paced breathing. Linear (spectral analysis) and nonlinear analyses (detrended fluctuation analysis (DFA)) were performed on the same RR series. At rest, women presented lower raw low frequency (LF) power and higher normalized high frequency (HF) power. Under these conditions, the LF/HF ratio of women was also lower than that of men (p < 0.05), but there were no differences in the short-term scaling exponent (α1). Even though both sexes showed a significant modification in linear and nonlinear measures of heart rate variability (HRV) (p < 0.05), women had a greater change in LF/HF ratio and α1 than men from rest to recovery. This study demonstrates that the cardiac autonomic function of women is more affected by supramaximal exercise than that of men. Additionally, DFA did not provide additional information about sexual dimorphisms, compared with conventional spectral HRV techniques.
Aerobic capacity of rats recovered from fetal malnutrition with a fructose-rich diet
Authors: Cambri Lucieli Teresa , Dalia Rodrigo Augusto , Ribeiro Carla , Rostom de Mello Maria Alice
Published: August 2010

The objective of this study was to analyze the aerobic capacity, through the maximal lactate steady-state (MLSS) protocol, of rats subjected to fetal protein malnutrition and recovered with a fructose-rich diet. Pregnant adult Wistar rats that were fed a balanced (17% protein) diet or a low-protein (6% protein) diet were used. After birth, the offspring were distributed into groups according to diet until 60 days of age: balanced (B), balanced diet during the whole experimental period; balanced–fructose (BF), balanced diet until birth and fructose-rich diet (60% fructose) until 60 days; low protein–balanced (LB), low-protein diet until birth and balanced diet until 60 days; and low protein–fructose (LF), low protein diet until birth and fructose-rich diet until 60 days. It was verified that the fructose-rich diet reduced body growth, mainly in the BF group. There was no difference among the groups in the load corresponding to the MLSS (B, 7.5 ± 0.5%; BF, 7.4 ± 0.6%; LB, 7.7 ± 0.4%; and LF, 7.7 ± 0.6% relative to body weight). However, the BF group presented higher blood lactate concentrations (4.8 ± 0.9 mmol·L–1) at 25 min in the load corresponding to the MLSS (B, 3.2 ± 0.9 mmol·L–1; LB, 3.4 ± 0.9 mmol·L–1; and LF, 3.2 ± 1.0 mmol·L–1). Taken together, these results indicate that the ability of young rats to perform exercise was not altered by intrauterine malnutrition or a fructose-rich diet, although the high fructose intake after the balanced diet in utero increased blood lactate during swimming exercises in rats.
Noninvasive measures of vascular health are reliable in preschool-aged children
Authors: Currie Katharine D. , Proudfoot Nicole A. , Timmons Brian W. , MacDonald Maureen J.
Published: August 2010

Measures of vascular health are known to be important predictors of cardiovascular disease in adulthood. The reliability of commonly used measures of vascular health has been demonstrated in school-aged children, adolescents, and adults; however, their reliability in preschool-aged children remains to be determined. Twenty 2- to 6-year-old children participated in 2 identical testing sessions on different days. Following 10 min of supine rest, carotid artery blood pressures and common carotid artery images were assessed simultaneously for 10 heart cycles, using applanation tonometry and B-mode ultrasound, respectively, while electrocardiogram (ECG) and infrared measures of arterial pressure waves at the dorsalis pedis were recorded continuously. Brachial artery blood pressures were determined using an automated oscillometric device. Carotid artery diameters and intima-media thickness (IMT) were analyzed using a semiautomated detection software program. Carotid compliance, distensibility, and stiffness index were calculated from carotid diameters and carotid blood pressures. Whole-body pulse-wave velocity (PWV) was determined from the time delay between the R spike of the ECG and the foot of the dorsalis pedis arterial pressure wave. Reliability of all measures was assessed using the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). The most reliable measures were carotid artery IMT and PWV with CVs of 2.6% and 3.5% and ICCs of 0.86 and 0.76, respectively. The lower reliability of carotid compliance and distensibility (ICC ≤ 0.63) is likely attributable to the variability of blood pressure measurements. This study confirms that vascular measurements demonstrate substantial reliability in preschool-aged children as young as 2 years.
Application of fuzzy logic to quality assessment of infrastructure projects at conceptual cost estimating stage
Authors: Fayek Aminah Robinson , Rodriguez Flores Jose Ruben
Published: August 2010

This paper describes a model to assess the quality of infrastructure projects at the conceptual cost estimating stage based on the extent to which a project exhibits the ideal relationships between the quantities and costs of each of its components, compared to an ideal project that meets the requirements of an organization. The output of the model is a quality score that can be used to compare a project against others in an organization. The model is intended for use by organizations in the project planning phase to help identify potential scope and (or) design deficiencies. A fuzzy expert system is used to model the relationships between the physical characteristics of a project and the expected quality using a cost ratio comparison between an ideal project (i.e., a cost model) and the project being compared. The fuzzy expert system provides the advantage of allowing assessments to be made in linguistic terms, which suits the way in which experts express themselves and captures heuristic knowledge of the experts in assessing the quality of a project at the conceptual cost estimating stage.
Contribution à l’étude de l’effet de la coagulation avant chloration sur la formation des trihalométhanes (THM) et composés organohalogénés (COX) dans les eaux alimentant la ville de Casablanca au MarocArticle envoyé à la Revue du génie et de la science de l'environnement.
Authors: Zidane Fatiha , Cheggari Karima , Blais Jean-François , Drogui Patrick , Bensaid Jalila , Ahmed Saïd Ibn
Published: August 2010

Cette étude visait la détermination et le suivi des sous-produits de désinfection (SPD) halogénés des eaux naturelles servant à la production d’eau potable de la ville de Casablanca au Maroc. Dans un premier temps, un suivi des paramètres physicochimiques des eaux naturelles a été effectué dans le but de caractériser ces eaux, pour lesquelles la demande en chlore a été déterminée à partir du traçage de la courbe de point de rupture (« break point »). Dans un deuxième temps, des eaux ont été synthétisées au laboratoire, sur la base des résultats des analyses effectuées précédemment. Ces eaux synthétiques ont fait l’objet, elles aussi, de la détermination des courbes de point de rupture. Afin d’évaluer les conséquences de la chloration, des tests de suivi des trihalométhanes (THM) et des composés organohalogénés (COX), avant et après coagulation ont été effectués. Les résultats obtenus pour les eaux naturelles ont montré une corrélation entre le carbone organique total (COT), la teneur et la nature des THM et les COX formés suite à la chloration. Aussi, les résultats ont montré que la coagulation avant chloration permet de réduire la formation de SPD.
A kinetic study of dimethyl sulfoxide reductase based on density functional theory
Authors: Hernandez-Marin Elizabeth , Ziegler Tom
Published: August 2010

We present a density functional theory study on the oxygen atom transfer (OAT) reaction of dimethyl sulfoxide (DMSO) with model complexes resembling a functional synthetic analogue of the molybdoenzyme DMSO reductase. The good agreement between our calculated Gibbs free energy profile and data derived from experimental kinetic parameters supports the reaction mechanisms of the oxygen atom transfer proposed in this study. When the mechanism involves the formation of a DMSO-bound intermediate, the calculations on the free energy surface provide valuable information that explains the origin of the apparent contradiction between the experimental findings and previous theoretical calculations with respect to the rate-limiting step of the reaction mechanism. The enzymatic mechanism of the OAT reaction is more complex than the mechanism of any synthetic analogue, mainly due to the formation of an enzyme-substrate adduct prior to the appearance of the substrate-bound intermediate. This study also presents a possible mechanism for the formation of such an adduct and the subsequent oxygen atom transfer. The mechanism involves a proton transfer to and from the substrate.
Microsolvation of the formic acid dimer — (HCOOH)2(H2O)n clusters with n = 1, . . ., 5
Authors: Nordstrom Cara M. , McGrath Alaina J. , Thakkar Ajit J.
Published: August 2010

Density functional theory and spin-component-scaled Møller–Plesset perturbation theory calculations are used to examine the microsolvation of the formic acid dimer. The lowest energy structures with n water molecules consist of a n-water cluster, not necessarily of lowest energy, with two formic acid molecules attached to its surface by hydrogen bonds. The total number of hydrogen bonds does not correlate directly with relative stability.
Ab initio studies of the vibrational spectra of some hydrogen-bonded complexes of fluoroacetylene
Authors: Ramasami Ponnadurai , Ford Thomas A.
Published: August 2010

Ab initio molecular orbital theory has been used to compute the properties of a number of hydrogen-bonded complexes between fluoroacetylene as proton donor and ammonia, water, hydrogen fluoride, phosphine, hydrogen sulfide, and hydrogen chloride as proton acceptors. The properties considered were the vibrational spectra, the molecular structures, the hydrogen-bond energies, and the electron densities, and one of the aims of the study was to ascertain whether there was any evidence of blue-shifting hydrogen-bond character in the complexes formed. The adducts with NH3, H2O, PH3, and H2S were of the conventional CH···X kind (X = N, O, P, S), with hydrogen-bond energies decreasing in the order NH3 > H2O > PH3≈ H2S. Those formed with HF and HCl showed the presence of three alternative structures; in addition to the CH···F(Cl) complexes, adducts of the F(Cl)H···F and F(Cl)H···π type were also found to be stationary points on the potential energy surfaces, with stabilities in the order F(Cl)H···π > CH···F(Cl) > F(Cl)H···F. The hydrogen-bond energies of the CH···X series correlated with the gas-phase basicities of the proton acceptors; moreover, the CH bond-length changes, the wavenumber shifts, the complex–monomer infrared intensity ratios of the CH stretching modes, and the amounts of charge transferred on complex formation were all found to track with the hydrogen-bond energies. All those properties considered here are consistent with the formation of red-shifting hydrogen bonds, to the exclusion of the blue-shifting alternatives.
Theoretical study of the rovibrational spectrum of He2–OCS
Authors: Wang Xiao-Gang , Carrington, Tucker
Published: August 2010

We report calculated microwave and infrared rovibrational transitions of the van der Waals complex He2–OCS. The calculations were done using a product basis, a Lanczos eigensolver, and potentials built from He–OCS, and He–He potential functions taken from the literature. All five of the large amplitude coordinates are treated exactly and calculations are done for J values up to five. All rovibrational levels are converged to 0.001 cm–1 by using basis sets with as many as 87 million funcions. Good agreement is found with previously reported experimental results. Although we assume that the dipole moment is along the OCS axis, we find transitions with appreciable intensity between different torsion states.
Ab initio calculations on C6H6···(HF)nclusters — X–H···π hydrogen bond
Authors: Grabowski Sławomir J. , Ugalde Jesus M.
Published: August 2010

MP2/6–311++G(d,p) calculations on C6H6···(HF)nclusters were performed and full optimizations were carried out for systems containing up to four HF molecules (n = 4) and calculations on the systems of C6vsymmetry were carried out for up to six HF molecules (n = 6). Cooperativity effects were analyzed for these molecular aggregates. It was found that F–H···π and F–H···F hydrogen bonds exist for these complexes and those interactions are enhanced as the number of HF molecules increases. The cooperativity effects cause numerous changes in geometrical, energetic, and topological parameters, the latter ones derived from the quantum theory of atoms in molecules. Various correlations between the analyzed parameters are presented. There are meaningful differences between the molecular graphs for the fully optimized complexes and those for the linear complexes of C6vsymmetry (for the latter, the linear chain of HF molecules is attached to a benzene molecule acting as the Lewis base). For the linear complexes, unique bond paths connect the H-attractor of the HF molecule and the ring critical point of the benzene molecule.
Homoselenocysteine — An oxygen or selenium acid in the gas phase?
Authors: Hurtado Marcela , Mó Otilia , Yáñez Manuel
Published: August 2010

The potential energy surface of l-homoselenocysteine (HSEC) has been explored through the use of B3LYP/6-311+G(d,p) calculations. In this survey, seventy-seven different conformers have been located. These local minima can be classified in four groups, A–D. Structures A, B, and D are stabilized by intramolecular hydrogen bonds (IMHBs) with the amino group acting as the hydrogen bond (HB) donor and the carbonyl group (structures A and D) or the hydroxyl group (structure B) as HB acceptors. The structures in set C present an IMHB with the amino group acting as the HB acceptor and the hydroxyl group as the HB donor. The stability order decreases in the following order: A > B > C > D. From their relative stabilities it can be concluded that only three of these conformers, namely A1, A4, and A5, would exist in the gas phase at room temperature. The most stable deprotonated form corresponds to a Se-deprotated species stabilized by a strong IMHB between the hydroxyl group and the Se atom. However, a direct deprotonation of the most stable neutrals lead to O-deprotonated species, which eventually isomerize to yield the global minimum. Hence, we can conclude that, quite unexpectedly, HSEC behaves as a Se acid in the gas phase, its intrinsic acidity being 1374 kJ mol–1at the B3LYP/6-311++G(3df,2p) level of theory. The most stable protonated forms are systematically the N-protonated ones, the global minimum being a structure stabilized through an IMHB involving the protonated amino group as the HB donor and the SeH group as the HB acceptor. The calculated gas-phase proton affinity (PA) at the B3LYP/6-311++G(3df,2p) level of theory is 930 kJ mol–1.
Regaining the Woodward–Hoffmann rules for chelotropic reactions via conceptual DFT
Authors: Jaque Pablo , Correa José V. , De Proft Frank , Toro-Labbé Alejandro , Geerlings Paul
Published: August 2010

In our continuous effort to retrieve the Woodward–Hoffmann rules from conceptual density functional theory (DFT), we have examined the last type of pericyclic reactions, i.e., chelotropic reactions. Both the initial hardness response and the dual descriptor have been investigated to predict the allowed and forbidden character for the addition of SO2to butadiene (4n system) and 1,3,5-hexatriene (4n + 2 system). It is shown that with both electronic descriptors, the conrotatory/disrotatory mode for the linear and nonlinear mechanisms are retrieved based on a density-only approach, free from consideration of orbital and (or) wave function symmetry. The dual descriptor moreover reveals that stabilizing interactions are presented only for the linear path, which can be considered as an overall favourable mechanism for a chelotropic reaction.
Characterization of enterohemorrhagicEscherichia coliO157:H7 00B015: a Shiga toxin producing but virulence-attenuated isolate
Authors: Wang Haiguang , Gu Jiang , Yu Shu , Zhang Weijun , Zhu Yefei , Zou Quanming , Zhu Fengcai , Mao Xuhu
Published: August 2010

Enterohemorrhagic Escherichia coli (EHEC) causes a wide range of systematic diseases in human and animals in 2 main ways: (1) production of Shiga toxin (Stx) and (2) induction of actin polymerization characterized by attaching and effacing (A/E) lesions. Stx is commonly targeted in the development of drugs and vaccines to control EHEC infection for its indispensible contribution to EHEC pathogenisis. In this study, we isolated a Stx-producing EHEC O157:H7 isolate 00B015 and found that its ability to induce actin polymerization was impaired. In addition, it reduces pathogenicity and decreases mortality in mice. Our results report a Stx-producing but virulence-attenuated EHEC isolate 00B015 and suggest that the formation of actin polymerization may help Stx-induced pathogenesis and have a more important contribution in EHEC infections.
Streptococcus salivariusmutants defective in mannose phosphotransferase systems show reduced sensitivity to mutacins I-T9 and R-3B
Authors: Nicolas Guillaume G. , Frenette Michel , Lavoie Marc C.
Published: August 2010

Twenty-four mutacin-producing Streptococcus mutans strains were screened for their propensity to produce class II one-peptide bacteriocin using a deferred antagonism assay. Streptococcus salivarius and 3 mutants defective in their mannose phosphotransferase systems (mannose-PTS) were used as sensitive strains to identify which mannose-PTS could act as the docking site for class II one-peptide bacteriocin activity. We observed that only 2 strains of S. mutans, T9 and 3B, potentially produce class II one-peptide bacteriocin, namely mutacins I-T9 and R-3B, but with no preference for any mannose-PTS complex as a target.
Contrasting effects of intervention with ETAand ETBreceptor antagonists in hypertension induced by angiotensin II and high-salt dietThis article is one of a selection of papers published in the two-part special issue entitled 20 Years of Endothelin Research.
Authors: Boesen Erika I. , Pollock Jennifer S. , Pollock David M.
Published: August 2010

Endothelin (ET) receptor antagonists are antihypertensive and renoprotective in angiotensin II (AngII)-induced hypertension if administered when AngII infusion commences, but their effects on established hypertension are poorly understood. We therefore tested the effects of intervening with an ETA(ABT-627) or ETB(A-192621) receptor antagonist after establishing hypertension with AngII (65 ng/min s.c.) plus 8% NaCl diet (AngII–HS) in rats. Prior to administration of ABT-627, AngII–HS and AngII–HS plus ABT-627 groups displayed robust hypertension (mean arterial pressure (MAP), 170 ± 5 and 165 ± 5 mm Hg versus 110 ± 3 mm Hg in normal salt control rats at day 7, P < 0.05). Administering ABT-627 from day 8 of AngII–HS treatment prevented further rises in MAP (168 ± 5 and 191 ± 3 mm Hg at day 13 in AngII–HS plus ABT-627 and AngII–HS, P < 0.001), without blunting the significant increases in urinary protein (19-fold), albumin (25-fold), or MCP-1 excretion (6- to 8-fold) or the reduction in creatinine clearance. Administering A-192621 from day 8 mildly exacerbated AngII–HS induced hypertension (P < 0.05 for AngII–HS versus AngII–HS plus A-192621 on days 11 and 12 only) and reduced plasma nitrite/nitrate concentration (P < 0.05), without affecting proteinuria, albuminuria, or creatinine clearance. These results confirm the importance of ETAreceptor signaling in maintaining AngII–HS hypertension and suggest that including ETBreceptor blockade in therapeutic approaches to treating hypertension would be ineffective or even counterproductive.
Endothelin signaling via guanine exchange factor C3G in renal glomerular mesangial cellsThis article is one of a selection of papers published in the two-part special issue entitled 20 Years of Endothelin Research.
Authors: Rufanova Victoriya A. , Alexanian Anna , Ostendorf Tammo , Bokemeyer Dirk , Prosser Simon , Miller Bradley , Sorokin Andrey
Published: August 2010

The guanine nucleotide exchange factor C3G is one of the mediators of endothelin-1 (ET-1) intracellular signaling cascades and is vital for kidney development and homeostasis. The aim of the current study was to analyze the specificity of ET-1-induced signaling via C3G in rat glomerular mesangial cells (GMC) and to investigate the biological significance of C3G during mesangioproliferative glomerulonephritis. In GMC, C3G expression was increased (1) in vivo after induction of the anti-Thy1 model of glomerulonephritis and (2) in cell culture experiments after fetal bovine serum incubation. To examine the consequences of C3G up-regulation, adenovirus-mediated gene transfer of C3G into cultured glomerular cells was done, and the GTP loading of the small G proteins Rap1 and R-Ras was analyzed. Overexpression of C3G in mesangial cells resulted in enhanced activation of Rap1, but failed to affect the GTP-bound status of R-Ras in ET-1-stimulated cells. C3G overexpression led to significant changes in GMC spreading and migration patterns in response to ET-1 stimulation and increased stress fiber formation, which was mimicked by Rap1A overexpression. Together, these findings suggest (1) the existence of regulatory mechanisms resulting in disease-related up-regulation of C3G in GMC and (2) that an increase in the C3G protein level may contribute to the resolution stage of mesangioproliferative glomerulonephritis by reducing GMC sensitivity to ET-1, modulating cellular motility, and actin dynamics.
EFFECT OF OXIDATION ON MODULUS OF 2D-C/SiBC COMPOSITES
Authors: ZHANG CHENGYU , QIAO SHENGRU , WU QI , HAN DONG , LI MEI
Published: August 2010

The effects of oxidation on the weight change (DW) and modulus change (DE) of an uncoated C / SiBC were investigated in 600–1000°C. The results show that larger DW does not mean larger damage. DE is more sensitive to the oxidation process than DW. At lower temperatures, a small DW can result in a large DE. The results result from the different oxidation rates of carbon fibers and pyrocarbon interphase.
ANALYSIS OF MAGNETIC PROPERTY MEASUREMENTS IN ULTRAFAST MAGNETIZATION DYNAMICS
Authors: WANG X. R.
Published: August 2010

Recent efforts in measuring magnetic properties of ferromagnets in their transient states created by the illumination of intensive femtosecond laser pulses are critically re-analyzed. It is concluded that, although various pump-probe architectures can provide certain information about the magnetic properties of disturbed ferromagnets in their transient states, these schemes measured neither coercivity nor remanence defined in the conventional sense. One of the popular experimental schemes cannot even be used to define the working definitions of coercivity and remanence becuase they depend on the details of pumping pulses.
Real-time data aggregation in contention-based wireless sensor networks
Authors: Zhang Jun , Jia Xiaohua , Xing Guoliang
Published: August 2010

We investigate the problem of delay constrained maximal information collection for CSMA-based wireless sensor networks. We study how to allocate the maximal allowable transmission delay at each node, such that the amount of information collected at the sink is maximized and the total delay for the data aggregation is within the given bound. We formulate the problem by using dynamic programming and propose an optimal algorithm for the optimal assignment of transmission attempts. Based on the analysis of the optimal solution, we propose a distributed greedy algorithm. It is shown to have a similar performance as the optimal one.
Toward trusted wireless sensor networks
Authors: Hu Wen , Tan Hailun , Corke Peter , Shih Wen Chan , Jha Sanjay
Published: August 2010

This article presents the design and implementation of a trusted sensor node that provides Internet-grade security at low system cost. We describe trustedFleck, which uses a commodity Trusted Platform Module (TPM) chip to extend the capabilities of a standard wireless sensor node to provide security services such as
message integrity, confidentiality, authenticity
, and
system integrity
based on RSA public-key and XTEA-based symmetric-key cryptography. In addition trustedFleck provides secure storage of private keys and provides platform configuration registers (PCRs) to store system configurations and detect code tampering. We analyze system performance using metrics that are important for WSN applications such as computation time, memory size, energy consumption and cost. Our results show that trustedFleck significantly outperforms previous approaches (e.g., TinyECC) in terms of these metrics while providing stronger security levels. Finally, we describe a number of examples, built on trustedFleck, of symmetric key management, secure RPC, secure software update, and
remote attestation
.
Positive Fixed Point of Strict Set Contraction Operators on Ordered Banach Spaces and Applications
Authors: Feng Meiqiang , Zhang Xuemei , Ge Weigao
Published: August 2010

The fixed point theorem of cone expansion and compression of norm type for a
strict set contraction operator is generalized by replacing the norms with a convex functional
satisfying certain conditions. We then show how to apply our theorem to prove the existence of
a positive solution to a second‐order differential equation with integral boundary conditions
in an ordered Banach space. An example is worked out to demonstrate the main results.
Underdetermined DOA Estimation via Independent Component Analysis and Time‐Frequency Masking
Authors: Jančovič Peter , Zou Xin , Köküer Münevver
Published: August 2010

This paper presents an algorithm for the estimation of the direction of arrival (DOA) in underdetermined situations, that is, there is more sources than sensors. The algorithm performs the estimation in an iterative manner, each iteration consists of two‐steps: first estimation of the DOA of a dominant source via the Independent Component Analysis and then removal of the detected source from the mixture via time‐frequency masking. Experiments, performed using speech signals mixed in real environment when only two microphones are used but three and four sources are present, demonstrate that the proposed algorithm can estimate the DOAs more accurately than two previously used underdetermined DOA algorithms.
The Role of PPARαActivation in Liver and Muscle
Authors: Burri Lena , Thoresen G. Hege , Berge Rolf K.
Published: August 2010

PPARαis one of three members of the soluble nuclear receptor family called peroxisome proliferator-activated receptor (PPAR). It is a sensor for changes in levels of fatty acids and their derivatives that responds to ligand binding with PPAR target gene transcription, inasmuch as it can influence physiological homeostasis, including lipid and carbohydrate metabolism in various tissues. In this paper we summarize the involvement of PPARαin the metabolically active tissues liver and skeletal muscle and provide an overview of the risks and benefits of ligand activation of PPARα, with particular consideration to interspecies differences.
Toll-Like Receptors in the Pathogenesis of Alcoholic Liver Disease
Authors: Petrasek Jan , Mandrekar Pranoti , Szabo Gyongyi
Published: August 2010

In the multifactorial pathophysiology of alcoholic liver disease (ALD), inflammatory cascade activation plays a central role. Recent studies demonstrated that Toll-like Receptors, the sensors of microbial and endogenous danger signals, are expressed and activated in innate immune cells as well as in parenchymal cells in the liver and thereby contribute to ALD. In this paper, we discuss the importance of gut-derived endotoxin and its recognition by TLR4. The significance of TLR-induced intracellular signaling pathways and cytokine production as well as the contribution of reactive oxygen radicals is evaluated. The contribution of TLR signaling to induction of liver fibrosis and hepatocellular cancer is reviewed in the context of alcohol-induced liver disease.
Spherical Aberration Correction Using Refractive-Diffractive Lenses with an Analytic-Numerical Method
Authors: Vázquez-Montiel Sergio , García-Liévanos Omar , Hernández-Cruz Juan Alberto
Published: August 2010

We propose an alternative method to design diffractive lenses free of spherical aberration for monochromatic light. Our method allows us to design diffractive lenses with the diffraction structure recorded on the last surface; this surface can be flat or curved with rotation symmetry. The equations that we propose calculate the diffraction profiles for any substratum, for any f-number, and for any position of the object. We use the lens phase coefficients to compensate the spherical aberration. To calculate these coefficients, we use an analytic-numerical method. The calculations are exact, and the optimization process is not required.
Preparation and Characterization of Chain-Extended Bismaleimide/Carbon Fibre Composites
Authors: Chandran M. Satheesh , Krishna M. , K. Salini , Rai K. S.
Published: August 2010

This paper presents an experimental study of the influence of the addition of aromatic diamine (MDA) to bismaleimide (BMI) resin on the crystallinity, solubility, melting temperature, and mechanical properties of BMI/carbon composites. The modified BMI was prepared through the chain extension with MDA via Michael addition reaction with molar ratio of 3 : 2 (BMI : MDA). Both modified and unmodified BMI were characterised for chemical structure, crystallinity, melting temperature, mechanical property, and morphology and fracture behaviour using FTIR, XRD, DSC, UTM, and SEM, respectively. The FTIR results revealed the formation of polymeric chain due to the broad N-H absorption. The modified resin was semicrystalline in nature having low melting temperature and hence showed good processibility. The modification of BMI resulted in decrease of pores and increase of tensile, flexural, and impact properties of the composites. Also, SEM studies of the tensile fractured specimens revealed that modification of BMI resulted in improved resin/fibre interfacial strength.
Chromatin Remodeling Is Required for Gene Reactivation after Decitabine-Mediated DNA Hypomethylation
Authors: Si Jiali , Boumber Yanis A. , Shu Jingmin , Qin Taichun , Ahmed Saira , He Rong , Jelinek Jaroslav , Issa Jean-Pierre J.
Published: August 2010

The DNA hypomethylating drug decitabine (DAC) reactivates silenced gene expression in cancer and is approved for the treatment of the myelodysplastic syndrome. Gene reactivation after DAC is variable and incompletely understood. Here, we established a cell line system (YB5) derived from the SW48 colon cancer cell line to study DAC-induced reactivation. YB5 contains a hypermethylated cytomegalovirus promoter driving green fluorescent protein (GFP), and the locus is transcriptionally silent. GFP reexpression can be achieved by DAC treatment, but the expression level of individual cells is heterogeneous. DAC-treated YB5 cells were separated into GFP-positive and GFP-negative subpopulations. By comparing DAC-treated sorted GFP-positive and GFP-negative cells, we found that their methylation levels were similarly decreased but that histone modifications and histone H3 densities were remarkably different. Despite a similar degree of (incomplete) DNA hypomethylation, GFP-positive cells reverted to an active chromatin structure marked by higher H3K9 acetylation, lower H3K27 trimethylation, and lower promoter nucleosome density. GFP-negative cells had histone modifications and promoter nucleosome density, similar to parental cells. On DAC withdrawal, gradual resilencing and remethylation occurred in both GFP-positive and GFP-negative cells, and the resilencing correlated with a gradual increase in nucleosome occupancy in GFP-positive cells. These data show that hypomethylation alone after DAC is insufficient for gene expression induction, and that chromatin resetting to an active state including nucleosome eviction is required for activation of protein expression. Our findings suggest that gene expression is the key in optimizing DAC treatment strategies in the clinic. Cancer Res; 70(17); 6968–77. ©2010 AACR.
miR-335 Directly Targets Rb1 (pRb/p105) in a Proximal Connection to p53-Dependent Stress Response
Authors: Scarola Michele , Schoeftner Stefan , Schneider Claudio , Benetti Roberta
Published: August 2010

Loss-of-function mutations of retinoblastoma family (Rb) proteins drive tumorigenesis by overcoming barriers to cellular proliferation. Consequently, factors modulating Rb function are of great clinical import. Here, we show that miR-335 is differentially expressed in human cancer cells and that it tightly regulates the expression of Rb1 (pRb/p105) by specifically targeting a conserved sequence motif in its 3′ untranslated region. We found that by altering Rb1 (pRb/p105) levels, miR-335 activates the p53 tumor suppressor pathway to limit cell proliferation and neoplastic cell transformation. DNA damage elicited an increase in miR-335 expression in a p53-dependent manner. miR-335 and p53 cooperated in a positive feedback loop to drive cell cycle arrest. Together, these results indicate that miR-335 helps control proliferation by balancing the activities of the Rb and p53 tumor suppressor pathways. Further, they establish that miR-335 activation plays an important role in the induction of p53-dependent cell cycle arrest after DNA damage. Cancer Res; 70(17); 6925–33. ©2010 AACR.
Recruitment of Phosphorylated NPM1 to Sites of DNA Damage through RNF8-Dependent Ubiquitin Conjugates
Authors: Koike Ayaka , Nishikawa Hiroyuki , Wu Wenwen , Okada Yukinori , Venkitaraman Ashok R. , Ohta Tomohiko
Published: August 2010

Protein accumulation at DNA double-strand breaks (DSB) is essential for genome stability; however, the mechanisms governing these events are not fully understood. Here, we report a new role for the nucleophosmin protein NPM1 in these mechanisms. Thr199-phosphorylated NPM1 (pT199-NPM1) is recruited to nuclear DNA damage foci induced by ionizing radiation (IR). Foci formation is impaired by depletion of the E3 ubiquitin ligases RNF8 and RNF168 or the E2 Ubc13, and pT199-NPM1 binds to Lys63-linked ubiquitin polymers in vitro. Thus, phosphorylated NPM1 may interact with RNF8-dependent ubiquitin conjugates at sites of DNA damage. The interaction was found to rely on T199 phosphorylation, an acidic tract, and an adjacent ubiquitin-interacting motif–like domain. Depletion of the breast cancer suppressor BRCA1 or its partner, RAP80, enhanced IR-induced NPM1 foci and prolonged persistence of the foci, possibly implicating BRCA1 in pT199-NPM1 action and dynamics. Replacement of endogenous NPM1 with its nonphosphorylable T199A mutant prolonged persistence of IR-induced RAD51 foci accompanied by unrepaired DNA damage. Collectively, our findings suggest that phosphorylated NPM1 is a novel component in DSB repair that is recruited by ubiquitin conjugates downstream of RNF8 and RNF168. Cancer Res; 70(17); 6746–56. ©2010 AACR.
Combination of Two Insulin-Like Growth Factor-I Receptor Inhibitory Antibodies Targeting Distinct Epitopes Leads to an Enhanced Antitumor Response
Authors: Dong Jianying , Demarest Stephen J. , Sereno Arlene , Tamraz Susan , Langley Emma , Doern Adam , Snipas Tracey , Perron Keli , Joseph Ingrid , Glaser Scott M. , Ho Steffan N. , Reff Mitchell E. , Hariharan Kandasamy
Published: August 2010

The insulin-like growth factor-I receptor (IGF-IR) is a cell surface receptor tyrosine kinase that mediates cell survival signaling and supports tumor progression in multiple tumor types. We identified a spectrum of inhibitory IGF-IR antibodies with diverse binding epitopes and ligand-blocking properties. By binding distinct inhibitory epitopes, two of these antibodies, BIIB4 and BIIB5, block both IGF-I and IGF-II binding to IGF-IR using competitive and allosteric mechanisms, respectively. Here, we explored the inhibitory effects of combining BIIB4 and BIIB5. In biochemical assays, the combination of BIIB4 and BIIB5 improved both the potency and extent of IGF-I and IGF-II blockade compared with either antibody alone. In tumor cells, the combination of BIIB4 and BIIB5 accelerated IGF-IR downregulation and more efficiently inhibited IGF-IR activation as well as downstream signaling, particularly AKT phosphorylation. In several carcinoma cell lines, the antibody combination more effectively inhibited ligand-driven cell growth than either BIIB4 or BIIB5 alone. Notably, the enhanced tumor growth–inhibitory activity of the BIIB4 and BIIB5 combination was much more pronounced at high ligand concentrations, where the individual antibodies exhibited substantially reduced activity. Compared with single antibodies, the BIIB4 and BIIB5 combination also significantly further enhanced the antitumor activity of the epidermal growth factor receptor inhibitor erlotinib and the mTOR inhibitor rapamycin. Moreover, in osteosarcoma and hepatocellular carcinoma xenograft models, the BIIB4 and BIIB5 combination significantly reduced tumor growth to a greater degree than each single antibody. Taken together, our results suggest that targeting multiple distinct inhibitory epitopes on IGF-IR may be a more effective strategy of affecting the IGF-IR pathway in cancer. Mol Cancer Ther; 9(9); 2593–604. ©2010 AACR.
Association of Human Cytochrome P450 1A1 (CYP1A1) and Sulfotransferase 1A1 (SULT1A1) Polymorphisms with Differential Metabolism and Cytotoxicity of Aminoflavone
Authors: Zheng Qiang , Sha Xianyi , Liu Jiansheng , Heath Elisabeth , LoRusso Patricia , Li Jing
Published: August 2010

Aminoflavone (AF), a clinically investigational novel anticancer agent, requires sequential metabolic activation by CYP1A1 and SULT1A1 to exert its antitumor activities. The purpose of this study was to determine the functional significance of common polymorphisms of human CYP1A1 and SULT1A1 on the metabolism and cytotoxicity of AF. To this end, Chinese Hamster V79 cells were genetically engineered to stably express human CYP1A1*1 (wild-type), CYP1A1*2C (I462V), or CYP1A1*4 (T461N) and coexpress human CYP1A1*1 with human SULT1A1*1 (wild-type), SULT1A1*2 (R213H), or SULT1A1*3 (M223V). The metabolism and cytotoxicity of AF were evaluated in these cellular models. All common variants of CYP1A1 and SULT1A1 were actively involved in the metabolic activation of AF, but with a varying degree of activity. Whereas CYP1A1 I462V variant exhibited a superior activity (mainly caused by a significantly higher Vmax) for hydroxylations of AF, expression of different CYP1A1 variants did not confer cell differential sensitivity to AF. The cells coexpressing CYP1A1*1 with SULT1A1*1, SULT1A1*2, or SULT1A1*3 displayed SULT1A1 allele-specific sensitivity to AF: SULT1A1*3 exhibited the highest sensitivity (IC50, 0.01 μmol/L), followed by SULT1A1*1 (IC50, 0.5 μmol/L), and SULT1A1*2 showed the lowest sensitivity (IC50, 4.4 μmol/L). These data suggest that the presence of low-activity SULT1A1*2 may predict poor response to AF, whereas the presence of high-activity CYP1A1/SULT1A1 alleles, especially combination of CYP1A1*2C and SULT1A1*3 or SULT1A1*1, may be beneficial to patients receiving AF. The present study provides a foundation for future clinical investigations of potential genetic biomarkers that may enable selection of patients for the greatest potential benefit from AF treatment. Mol Cancer Ther; 9(10); 2803–13. ©2010 AACR.