bluuebunny/crossref_metadata_2025 huggingface dataset:
An update review on risk factors and scales for prediction of deep sternal wound infections
Authors: Buja Alessandra , Zampieron Alessandra , Cavalet Sara , Chiffi Daniele , Sandonà Paolo , Vinelli Angela , Baldovin Tatjana , Baldo Vincenzo
Published: December 2011

Surgical site infections are the most common nosocomial infections in surgical patients. The preventable and the unmodifiable risk factors for deep sternal wound infections (DSWI) have been amply assessed in the literature. The aim of this review was to describe the results of the numerous published studies to describe all the DSWI risk factors and the scales devised to predict SWI, with a view to providing an update on this issue. A comprehensive search of the Medline and Embase databases was performed (considering studies from January 1995 to April 2011); and a manual search was also conducted using references cited in original publications and relevant review articles. There are several risk factors associated with DSWI, which could be classified in four categories as demographic (e.g. sex and age), behavioural (e.g. smoking and obesity), baseline clinical conditions (e.g. diabetes, hypertension and COPD) and surgical operative risk factors (e.g. duration of operation and emergency operation). Six scales for predicting the risk of DSWI are described in the literature: they vary not only in accuracy but also in ease of application and they are applied at different times (some only preoperatively and others also postoperatively). This study provides a broad update on our knowledge of the risk factors for DSWI and the scales for prediction with a view to improving the management of infections at cardiosurgery units.
ORGANIC GEOCHEMISTRY AND PETROLOGY OF A LOWER JURASSIC (PLIENSBACHIAN) PETROLEUM SOURCE ROCK FROM AÏT MOUSSA, MIDDLE ATLAS, MOROCCO
Authors: Sachse V. F. , Leythaeuser D. , Grobe A. , Rachidi M. , Littke R.
Published: December 2011

Organic‐rich silty marls and limestones (Pliensbachian to earliest Toarcian) exposed at Aït Moussa in Boulemane Province are the only known example of an effective petroleum source rock in the Middle Atlas of Morocco. In this study, petrological and organic‐geochemical analyses (vitrinite reflectance measurements, Rock‐Eval pyrolysis, GC‐MS) were carried out in order to evaluate the maturity, quality and quantity of the organic matter (OM) and to investigate the depositional environment of these source rocks. Results indicate the presence of Type I/II kerogen which was deposited under marine conditions with an input of predominantly algal‐derived organic matter. The presence of woody particles indicates minor input of terrestrial material. Organic‐geochemical and biomarker analyses are consistent with deposition of carbonate‐rich sediments under oxygen‐depleted but not anoxic conditions. In terms of thermal maturity, the sediments have reached the oil window (0.5–0.6 %VRt) but not peak oil generation, although petroleum generation and migration are indicated by organic geochemical and microscopic evidence.

Kinetic parameters derived from an investigation of petroleum generation characteristics show that the kerogen decomposes within a narrow temperature interval due to the fairly homogenous structure of the algal‐derived organic matter. The kinetic parameters together with vitrinite reflectance data were used to construct a ID model of the burial, thermal and maturation history of the Aït Moussa locality. The model suggested that deepest burial (approx. 3200 m) for the Pliensbachian succession took place in the Eocene (approx. 40 Ma). Two phases of hydrocarbon generation occurred, the first in the Late Jurassic/Early Cretaceous (approx. 150 Ma), and the second at the time of deepest burial (Eocene).
IMPACT OF DIAGENESIS ON RESERVOIR QUALITY IN RAMP CARBONATES: GIALO FORMATION (MIDDLE EOCENE), SIRT BASIN, LIBYA
Authors: Swei G. H. , Tucker Maurice E.
Published: December 2011

The reservoir quality of Middle Eocene carbonates in the intracratonic Sirt Basin is strongly influenced by depositional facies and various diagenetic processes. Based on data from core samples and well logs from five boreholes in the Assumood and Sahl gasfields in the subsurface of the north‐central Sirt Basin, six major carbonate facies (and fourteen microfacies) are distinguished in the Middle Eocene Gialo Formation (thickness ∼1100 ft/335 m). Wackestones‐packstones dominate the Gialo Formation with abundant grains of larger benthic foraminifera, especially nummulites, in a matrix composed mostly of finely comminuted bioclastic material. Sediments were deposited as a mosaic of facies on a broad carbonate ramp in moderate‐energy nummulite‐packstone banks, with locally restricted back‐bank lagoons and fore‐bank areas of foraminiferal debris passing to offshore lime mudstones.

Marine diagenesis was minor with micritization of bioclasts and rare vadose marine fibrous cements. Sparry calcite cements are ubiquitous and were precipitated during shallow to moderate burial from seawater and/or meteoric water, the latter largely unaffected by surface‐pedogenic processes. This is indicated by the fabrics and pre‐ and post‐compaction precipitation of drusy spar and echinoderm overgrowths, and supported by their bright‐to‐dull luminescence and low negative δ18O signatures (‐2.68 to ‐4.16%° PDB). Some early neomorphic alteration of calcitic bioclasts is suggested by bright CL and marine to low negative δ18O values (‐1.06 to –3.93%° PDB). Bioclastic grains have δ13C values ranging between 0.76 and 1.19%° PDB, interpreted as marine signatures. Similar low positive δ13C values of the cements (0.9 to 1.05 %°) indicate a source of carbonate from dissolution of grains and/or seawater/meteoric water, but without any near‐surface/soil effects. Dissolution of grains and matrix, notably originally aragonitic grains but also the originally high‐Mg calcite nummulites, was a major porosity‐enhancing process, and took place from shallow to moderate burial depths. Fractures may locally have increased porosity too.

Shallow‐water packstones/rudstones containing both primary intergranular and secondary biomouldic porosity have the best reservoir quality and these are concentrated in the upper parts (top ∼100 ft/30 m) of the wells, with porosity‐permeability decreasing downwards. This trend relates to the broad, large‐scale facies pattern of more mud‐dominated facies giving way upwards to more grainy, nummulite‐dominated facies as a result of an overall shallowing of the depositional environment. In addition, the influx of meteoric waters in the upper part of the Gialo platform, before drowning and deposition of the overlying Augila Shale, increased porosity through dissolution. This integrated study has helped in understanding the reservoir heterogeneity and hydrocarbon potential of the Gialo carbonates.
EVALUATION OF HYDROCARBON PROSPECTS USING SURFACE GEOCHEMICAL DATA WITH CONSTRAINTS FROM GEOLOGICAL AND GEOPHYSICAL OBSERVATIONS: SAURASHTRA BASIN, INDIA
Authors: Mani D. , Patil D. J. , Kalpana M. S. , Dayal A. M.
Published: December 2011

The Saurashtra Basin in western India is considered to have significant hydrocarbon potential. However conventional exploration methods, particularly for Mesozoic prospects, have been hampered by the thick basalt cover. In this study, near‐surface geochemical methods are used to investigate the generation of thermogenic gaseous hydrocarbons in the basin. Shallow soil samples were collected from favourable locations identified by integrated geophysical and geochemical studies. The compositional and isotopic signatures of adsorbed gaseous hydrocarbons (methane through pentane) together with soil iodine concentrations were used as surface indicators of petroleum micro‐seepages. High concentrations of adsorbed thermogenic methane (C1= 518 ppb) and ethane plus higher hydrocarbons (ΣC2+= 977 ppb) along with iodine concentrations up to 68.5 ppm were observed. Total organic and inorganic carbon (TOC and TIC) measurements, fluorescence and X‐ray diffraction (XRD) studies showed that the near‐surface hydrocarbon occurrences were seepage related. Elevated hydrocarbon and iodine concentrations were coincident with dykes and lineaments in the study area, which probably served as conduits for the micro‐seepage of hydrocarbons.
Thermal Performance Measurement of a Bump Type Gas Foil Bearing Floating on a Hollow Shaft for Increasing Rotating Speed and Static Load
Authors: Kim Tae Ho , Song Jin Woo , Lee Yong-Bok , Sim Kyuho
Published: December 2011

Identifying thermal characteristics of gas foil bearings (GFBs) provides an insight for successful implementation into high speed oil-free turbomachinery. The paper presents temperature measurements of a bump type GFB floating on a hollow shaft for various operating conditions. Two angular ball bearings support the hollow shaft at one end (right), and the other end (left) is free. Test GFB has the outer diameter of 100 mm and the axial length of 45 mm, and the hollow shaft has the outer and inner diameters of 60 mm and 40 mm, respectively. An electric motor drives the hollow shaft using a spline coupling connection. A mechanical loading device provides static loads on test GFB upward via a metal wire, and a strain gauge type load cell placed in the middle of the wire indicates the applied loads. During experiments for shaft speeds of 5 krpm, 10 krpm, and 15 krpm and with static loads of 58.9 N (6 kgf), 78.5 N (8 kgf), and 98.1 N (10 kgf), twelve thermocouples measure the outer surface temperatures of test GFB at four angular locations of 45 deg, 135 deg, 215 deg, and 315 deg, with an origin at the top foil free end, and three axial locations of bearing centerline and both side edges at each angle. Two infrared thermometers measure the outer surface temperature of the hollow shaft at free and supported ends close to test GFB. Test results show that GFB temperatures increase as the shaft speed increases and as the static load increases, with higher temperatures in the loaded zone (135 deg and 215 deg) than those in the unloaded zone (45 deg and 315 deg). In general, the recorded temperatures are highest at 225 deg where a highest hydrodynamic pressure is expected to build up. Measured temperatures at the bearing centerline are higher than those at the side edges, as expected. In addition, large thermal gradients are recorded in the hollow shaft along the axial direction with higher temperatures at the supported end. The axial thermal gradient of the shaft is thought to cause higher temperatures at the bearing right edge facing the ball bearing support than those at the left edge. The paper presents test data along with detailed test GFB/shaft geometries and material properties.
Safety Assessment of Reactor Pressure Vessel Integrity for Loss of Coolant Accident Conditions
Authors: Beukelmann Dieter , Guo Wenfeng , Holzer Wieland , Kauer Robert , Münch Wolfgang , Reichel Christoph , Schöner Peter
Published: December 2011

One of the critical issues for reactor pressure vessel (RPV) structural integrity is related to the pressurized thermal shock (PTS) event. Therefore, within the framework of safety assessments special emphasis is given to the effect of PTS-loadings caused by the nonuniform azimuthal temperature distribution due to cold water plumes or stripes during emergency coolant injection. This paper describes the method used to predict the thermal mechanic boundary conditions (system pressure and wall temperature). Using a system code the pressure and global temperature distributions were calculated, systematically varying the leak size and the location of the coolant water injection. Spatial and temporal temperature distributions in the main circulation pipes and at the RPV wall were predicted by mixing analyses with a computational fluid dynamics (CFD) code. The model used for these calculations was validated by post-test calculations of a UPTF (upper plenum test facility) experiment simulating cold leg injection during a small break loss of coolant accident (LOCA). Comparison with measured temperatures showed that the modeling used is suitable to obtain enveloping results. Fracture mechanics analyses were carried out for circumferential flaw sizes in the weld joint near the core region and between the RPV shell and the flange, as well as for axial flaws in the nozzle corner. Stress intensity factors KI were calculated numerically using the finite element program ansys and analytically on the basis of weight and polynomial influence functions using stresses obtained from elastic finite element analyses. Benchmark tests revealed good agreement between the results from numerical and analytical calculations. For all regions of the RPV investigated and the most severe transients it was demonstrated that a large safety margin against brittle crack initiation exists and brittle fracture of the RPV can be excluded.
Two-Phase Microchannel Heat Sinks: Theory, Applications, and Limitations
Authors: Mudawar Issam
Published: December 2011

Boiling water in small channels that are formed along turbine blades has been examined since the 1970s as a means to dissipating large amounts of heat. Later, similar geometries could be found in cooling systems for computers, fusion reactors, rocket nozzles, avionics, hybrid vehicle power electronics, and space systems. This paper addresses (a) the implementation of two-phase microchannel heat sinks in these applications, (b) the fluid physics and limitations of boiling in small passages, and effective tools for predicting the thermal performance of heat sinks, and (c) means to enhance this performance. It is shown that despite many hundreds of publications attempting to predict the performance of two-phase microchannel heat sinks, there are only a handful of predictive tools that can tackle broad ranges of geometrical and operating parameters or different fluids. Development of these tools is complicated by a lack of reliable databases and the drastic differences in boiling behavior of different fluids in small passages. For example, flow boiling of certain fluids in very small diameter channels may be no different than in macrochannels. Conversely, other fluids may exhibit considerable “confinement” even in seemingly large diameter channels. It is shown that cutting-edge heat transfer enhancement techniques, such as the use of nanofluids and carbon nanotube coatings, with proven merits to single-phase macrosystems, may not offer similar advantages to microchannel heat sinks. Better performance may be achieved by careful optimization of the heat sink’s geometrical parameters and by adapting a new class of hybrid cooling schemes that combine the benefits of microchannel flow with those of jet impingement.
On Mechanical Properties of Composite Sandwich Structures With Embedded Piezoelectric Fiber Composite Sensors
Authors: Konka Hari P. , Wahab M. A. , Lian K.
Published: December 2011

The smart sandwich structures have been widely used in the aerospace, automobile, marine, and civil engineering applications. A typical smart sandwich structure is usually comprised of two stiff face skins separated by a thick core with variety of embedded sensors to monitor the performance of the structures. In this study, the smart composite sandwich structure (CSS) samples are fabricated with glass microballoons syntactic foam core and resin infused glass-fiber face skins (with piezoelectric fiber composite sensors (PFCS) embedded inside the resin infused glass-fiber face skins). One of the main concerns associated with embedding sensors inside composite structures is the structural continuity, compatibility, and interface stress concentrations caused by the significant differences in material property between sensor and host structures. PFCS are highly flexible, easily embeddable, highly compatible with composite structures and their manufacturing processes, which makes them ideal for composite health monitoring applications. In this study, in-plane tensile, tension–tension fatigue, short beam shear, and flexural tests are performed to evaluate the effect on strengths/behavior of the CSS samples due to embedded PFCS. Then carefully planned experiments are conducted to investigate the ability of the embedded PFCS to monitor the stress/strain levels and detect damages in CSS using modal analysis technique. The tensile tests show that both the average ultimate strength and the modulus of elasticity of the tested laminate with or without embedded PFCS are within 7% of each other. The stress–life (S-N) curves obtained from fatigue tests indicates that the fatigue lives and strengths with and without the PFCS are close to each other as well. From short beam and flexural test results, it is observed that embedded PFCS leads to a reduction of 5.4% in the short beam strength and 3.6% in flexural strength. Embedded PFCS’s voltage output response under tension–tension fatigue loading conditions has been recorded simultaneously to study their ability to detect the changes in input loading conditions. A linear relationship has been observed between the changes in the output voltage response of the sensor and changes in the input stress amplitude. This means that by constantly monitoring the output response of the embedded PFCS, one could effectively monitor the magnitude of stress/strain acting on the structure. Experiments are also performed to explore the ability of the embedded PFCS to detect the damages in the structures using modal analysis technique. Results from these experiments show that the PFCS are effective in detecting the initiations of damages like delamination inside these composite sandwich structures through changes in natural frequency modes. Hence embedded PFCS could be an effective method to monitor the health of the composite sandwich structures’ in-service conditions.
Middle Stone Age Bedding Construction and Settlement Patterns at Sibudu, South Africa
Authors: Wadley Lyn , Sievers Christine , Bamford Marion , Goldberg Paul , Berna Francesco , Miller Christopher
Published: December 2011

Early humans constructed sleeping mats from local plants, including some with insecticidal properties.
Empathy and the Laws of Affect
Authors: Panksepp Jaak
Published: December 2011

Can animal models provide insights into human empathy and promote nurturance?
Weed-Out Courses Hamper Diversity
Authors: Mervis Jeffrey
Published: December 2011

More than 400 chairs from the top-200 research universities and from minority-serving institutions have responded to a series of questions on their attitudes toward underrepresented minorities and women.
Possible Laboratory Contamination Leads to Incorrect Reporting of Vibrio cholerae O1 and Initiates an Outbreak Response
Authors: Smith Anthony M. , Keddy Karen H. , Ismail Husna , Tau Nomsa , Sooka Arvinda , Archer Brett N. , Thomas Juno , Crisp Noreen
Published: December 2011

Vibrio cholerae
O1 in a river water specimen in South Africa was reported, and a public health response followed in order to prevent an outbreak. Further investigation determined this to be a pseudoalert of
V. cholerae
O1, possibly linked to laboratory contamination. Following culture of bacteria from the water specimen, the testing laboratory possibly contaminated the culture with a
V. cholerae
O1 reference strain and then mistakenly reported isolation of
V. cholerae
O1.
Effectiveness of an Integrated Real-Time PCR Method for Detection of the Mycobacterium tuberculosis Complex in Smear-Negative Extrapulmonary Samples in an Area of Low Tuberculosis Prevalence
Authors: Moure Raquel , Martín Rogelio , Alcaide Fernando
Published: December 2011

Early extrapulmonary tuberculosis (EPTB) diagnosis is particularly difficult. Among 108 smear-negative extrapulmonary samples showing a positive culture for
Mycobacterium tuberculosis
complex (43 body fluids and 65 nonliquid specimens), 63 (58.3%) were positive with the Xpert MTB/RIF assay (GX). GX sensitivity was quite low for samples from sterile locations (especially for pleural fluids: 26.9%) but high for some nonliquid samples, like abscess aspirates (76.5%). In summary, GX may be a useful tool to be considered for EPTB diagnosis.
Crystal Structure of the Japanese Encephalitis Virus Envelope Protein
Authors: Luca Vincent C. , AbiMansour Jad , Nelson Christopher A. , Fremont Daved H.
Published: December 2011

Japanese encephalitis virus (JEV) is the leading global cause of viral encephalitis. The JEV envelope protein (E) facilitates cellular attachment and membrane fusion and is the primary target of neutralizing antibodies. We have determined the 2.1-Å resolution crystal structure of the JEV E ectodomain refolded from bacterial inclusion bodies. The E protein possesses the three domains characteristic of flavivirus envelopes and epitope mapping of neutralizing antibodies onto the structure reveals determinants that correspond to the domain I lateral ridge, fusion loop, domain III lateral ridge, and domain I-II hinge. While monomeric in solution, JEV E assembles as an antiparallel dimer in the crystal lattice organized in a highly similar fashion as seen in cryo-electron microscopy models of mature flavivirus virions. The dimer interface, however, is remarkably small and lacks many of the domain II contacts observed in other flavivirus E homodimers. In addition, uniquely conserved histidines within the JEV serocomplex suggest that pH-mediated structural transitions may be aided by lateral interactions outside the dimer interface in the icosahedral virion. Our results suggest that variation in dimer structure and stability may significantly influence the assembly, receptor interaction, and uncoating of virions.
Role of β-Catenin and TCF/LEF Family Members in Transcriptional Activity of HIV in Astrocytes
Authors: Narasipura Srinivas D. , Henderson Lisa J. , Fu Sidney W. , Chen Liang , Kashanchi Fatah , Al-Harthi Lena
Published: December 2011

The Wnt/β-catenin pathway is involved in diverse cell functions governing development and disease. β-Catenin, a central mediator of this pathway, binds to members of the TCF/LEF family of transcription factors to modulate hundreds of genes. Active Wnt/β-catenin/TCF-4 signaling plays a significant role in repression of HIV-1 replication in multiple cell targets, including astrocytes. To determine the mechanism by which active β-catenin/TCF-4 leads to inhibition of HIV replication, we knocked down β-catenin or TCF/LEF members in primary astrocytes and astrocytomas transiently transfected with an HIV long terminal repeat (LTR)-luciferase reporter that contained an integrated copy of the HIV LTR-luciferase construct. Knockdown of either β-catenin or TCF-4 induced LTR activity by 2- to 3-fold under both the episomal and integrated conditions. This knockdown also increased presence of serine 2-phosphorylated RNA polymerase II (Pol II) on the HIV LTR as well as enhanced its processivity. Knockdown of β-catenin/TCF-4 also impacted tethering of other transcription factors on the HIV promoter. Specifically, knockdown of TCF-4 enhanced binding of C/EBPβ, C/EBPδ, and NF-κB to the HIV LTR, while β-catenin knockdown increased binding of C/EBPβ and C/EBPδ but had no effect on NF-κB. Approximately 150 genes in astrocytes were impacted by β-catenin knockdown, including genes involved in inflammation/immunity, uptake/transport, vesicular transport/exocytosis, apoptosis/cellular stress, and cytoskeleton/trafficking. These findings indicate that modulation of the β-catenin/TCF-4 axis impacts the basal level of HIV transcription in astrocytes, which may drive low level/persistent HIV in astrocytes that can contribute to ongoing neuroinflammation, and this axis also has profound effects on astrocyte biology.
Enhancement of Hepatitis B Virus Replication by Androgen and Its Receptor in Mice
Authors: Tian Yongjun , Kuo Cheng-fu , Chen Wen-ling , Ou Jing-hsiung James
Published: December 2011

Hepatitis B virus (HBV) is an important pathogen that chronically infects more men than women. To understand the molecular mechanism of this gender disparity, we analyzed HBV replication in transgenic mice that carried the HBV genome with or without the ability to express the HBV X protein (HBx). We found that gender had no effect on HBV surface antigen (HBsAg), DNA, and RNA levels in mice before puberty, but its effect on HBV after puberty was apparent, with HBV replicating approximately twice more efficiently in male mice than in female mice whether or not HBx was expressed. The castration of male mice resulted in a reduction of HBV HBsAg, DNA, and RNA levels, which could be partially restored by the injection of the androgen agonist R1881, indicating a positive role of androgen in HBV replication. The introduction of HBV genomic DNA and androgen receptor (AR) short hairpin RNA (shRNA) into the liver of naïve mice by hydrodynamic injection revealed that the effect of androgen on HBV was dependent on its receptor, which apparently could also stimulate HBV replication via an androgen-independent pathway. Further studies indicated that the two previously identified androgen response elements (AREs) in the HBV genome could indeed mediate the effect of androgen on HBV RNA transcription and DNA replication
in vivo
. These effects of androgen and its receptor on HBV thus provide an explanation for why men have a higher risk of HBV infection than women.
Regional patterns in mercury and selenium concentrations of yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus) in the Pacific Ocean
Authors: Ferriss Bridget E. , Essington Timothy E.
Published: December 2011

Mercury (Hg) concentrations in high trophic level fish, such as bigeye tuna ( Thunnus obesus ) and yellowfin tuna ( Thunnus albacares ), can often exceed consumption advisories. Here we sampled 444 yellowfin and bigeye tuna to determine whether tuna Hg concentration varies regionally in the eastern and central Pacific Ocean and whether this variation corresponds to environmental characteristics that promote the bioavailability of Hg. Of the five regions sampled, we found significantly higher Hg concentrations in the eastern equatorial region (5°S–5°N; 110°W–120°W) for both species. Hg concentrations in this region were elevated by 0.22 and 0.17 µg·g–1for yellowfin and bigeye tuna, respectively, compared with Hg concentrations in the other regions. Tuna selenium concentrations, which may alter the toxicity of Hg, did not vary by region. Oceanographic data indicated that the eastern equatorial region had elevated chlorophyll a concentrations and shallow minimum oxygen depths, both of which promote Hg methylation. These findings suggest that methylation-promoting mechanisms may translate into regional variation in the Hg concentrations of highly mobile, high trophic level fish.
Seasonal shift in the effects of predators on juvenile Atlantic salmon (Salmo salar) energetics
Authors: Ward Darren M. , Nislow Keith H. , Folt Carol L.
Published: December 2011

Predator effects on prey populations are determined by the number of prey consumed and effects on the traits of surviving prey. Yet the effects of predators on prey traits are rarely evaluated in field studies. We measured the effects of predators on energetic traits (consumption and growth rates) of juvenile Atlantic salmon ( Salmo salar ) in a large-scale field study. Salmon fry were released at 18 sites that encompassed a wide range of predatory slimy sculpin ( Cottus cognatus ) abundance. We sampled salmon after 21 and 140 days to measure salmon growth and estimate consumption using a mass-balance model of methylmercury accumulation. Salmon population density was reduced fivefold at sites with abundant sculpin. Over the early season, salmon consumed less where sculpin were abundant, suggesting that reduced foraging under predation risk contributed to predator-caused mortality. In contrast, over the late season, salmon grew more where sculpin were abundant, suggesting that compensatory growth at reduced salmon population density moderated predator-caused mortality. Predator effects on prey energetics can drive variation in survival and growth, with important consequences for population dynamics.
Estimation du rayonnement mensuel global par jour par deux approches météorologiques en Algérie
Authors: Mesri M. , Cheknane A. , Bachari N. , Rougab I.
Published: December 2011

Nous présentons une méthode d’estimation de la moyenne mensuelle du rayonnement global reçu au sol par jour sous un ciel clair et moyen. Elle permet de valider des modèles météorologiques cités dans la littérature. Ces derniers utilisent des relations qui permettent de transformer les données mesurées d’insolation en flux global d’irradiation solaire. Ceci est en parfaite adéquation avec la nature du réseau de mesures algérien, caractérisé par une faible densité de stations radiométriques, mais qui fournit des données de durée d’ensoleillement. Notre étude prend en charge deux modèles : le modèle d’Angstrom et le modèle de Coppolino. Les résultats obtenus montrent que ce dernier modèle permet de prédire la moyenne mensuelle du rayonnement journalier avec une bonne fiabilité.
A generalization on projectile motion with linear resistance
Authors: Morales Daniel A.
Published: December 2011

We study the motion of a projectile with linear drag shot from a nonzero height on an inclined plane that makes an angle [Formula: see text] with the horizontal, and obtain analytical expressions for the range, the time of flight, and the angle between the initial and final velocities as functions of the firing angle in terms of the Lambert W function. For [Formula: see text] = 0, analytical expressions are also obtained for the maximum range, the optimum angle, and the optimum time of flight in terms of the Lambert W function. In the general case, we prove that when the projectile travels along the path of maximum range, the initial and final velocities are perpendicular.
Ingénierie géometrique des GUTs en théorie des supercordes
Authors: Belhaj A. , Chabab M. , Medari L. , Saidi E.H.
Published: December 2011

Nous étudions l’ingénierie géométrique des modèles de jauge supersymétriques de type GUT dans le cadre des supercordes type II. Ces constructions ont une interprétation naturelle en terme de la compactification de la théorie-F sur des variétés des Calabi–Yau à quatre dimensions complexes admettant des surfaces de del Pezzo dPk comme des quatre-cycles. Nous présentons entre autres, des modèles locaux de la théorie-F, mettant en jeu des correspondances particulières entre les algèbres de Lie exceptionnelles, les sufaces dPk et les groupes de symétrie de jauge permettant ainsi de générer des modèles supersymétriques N = 1 à quatre dimensions présentant de grands intérêts phénoménologiques. Tout comme nous proposons certaines extensions de ces modèles, potentiellement prometteuses.
Influence of DNA extraction and PCR amplification on studies of soil fungal communities based on amplicon sequencing
Authors: Xu Lihui , Ravnskov Sabine , Larsen John , Nicolaisen Mogens
Published: December 2011

Most studies involving next-generation amplicon sequencing of microbial communities from environmental studies lack replicates. DNA extraction and PCR effects on the variation of read abundances of operational taxonomic units generated from deep amplicon 454 pyrosequencing was investigated using soil samples from an agricultural field with diseased pea. One sample was extracted four times, and one of these samples was PCR amplified four times to obtain eight replicates in total. Results showed that species richness was consistent among replicates. Variation among dominant taxa was low across replicates, whereas rare operational taxonomic units showed higher variation among replicates. The results indicate that pooling of several extractions and PCR amplicons will decrease variation among samples.
Isolation and molecular characterization of Chikungunya virus from the Andaman and Nicobar archipelago, India: evidence of an East, Central, and South African genotype
Authors: Muruganandam N. , Chaaithanya I.K. , Senthil G.S. , Shriram A.N. , Bhattacharya D. , JeevaBharathi G.S. , Sudeep A.B. , PradeepKumar N. , Vijayachari P.
Published: December 2011

Chikungunya virus (CHIKV) is an Alphavirus belonging to the family Togaviridae. In 2006, CHIKV infection struck the Andaman and Nicobar archipelago, with an attack rate of 60%. There were more than 10 cases with acute flaccid paralysis simulating the Guillian Barre Syndrome. The majority of the patients presented severe joint pain. The cause for such an explosive nature of the outbreak with increased morbidity was not known. The isolation of CHIKV was attempted and succeeded from nine subjects presenting clinical symptoms of Chikungunya fever. The cDNA of all the isolates was sequenced for partial E1 and nsP1 genes. Sequences were aligned based on the double locus sequence typing concept. The phylogenetic analysis shows that sequences of Andaman isolates grouped with the East, Central, and South African genotype of virus isolates from India, Sri Lanka, and Réunion. The genetic distance between Andaman isolates and the Réunion isolates was very small. The phylogenetic analysis confirmed the origin of the isolates responsible for the first ever confirmed CHIKV outbreak in these islands to be the East, Central, and South African genotype. In this manuscript, we discuss the involvement of the East, Central, and South African strain with the Chikungunya fever outbreak in this archipelago and double locus sequence typing as a first time approach.
Laminin-α1 LG4–5 domain binding to dystroglycan mediates muscle cell survival, growth, and the AP-1 and NF-κB transcription factors but also has adverse effects
Authors: Zhou Yan Wen , Munoz Jesus , Jiang Daifeng , Jarrett Harry W.
Published: December 2011

In our previous studies, we showed laminin binds α-dystroglycan in the dystrophin glycoprotein complex and initiates cell signaling pathways. Here, differentiated C2C12 myocytes serve as a model of skeletal muscle. C2C12 cells have a biphasic response to the laminin-α1 laminin globular (LG) 4–5 domains (1E3) dependent on the concentration used; at low concentrations of 1E3 (<1 μg/ml), myoblast proliferation is increased while higher concentrations (>1 μg/ml) cause apoptosis in myoblasts and differentiated myotubes. This alters the activation of the transcription factors activator protein-1 (AP-1) and NF-κB via laminin-dystrophin glycoprotein complex (DGC)-src-grb2-sos1-Rac1-Pak1-c-jun N-terminal kinase (JNK)p46 and laminin-DGC-Gβγ-phosphatidylinositol 3-kinase (PI3K)-Akt pathways, respectively. A specific antibody against Ser63 phosphorylated c-jun completely blocks or supershifts the AP-1-DNA binding resulting from laminin binding but only partially blocks or supershifts the AP-1-DNA binding resulting from 1E3. This suggests that AP-1 contains phosphorylated c-jun in the presence of hololaminin but contains a different composition in the presence of 1E3. Nuclear NF-κB was only upregulated by a low concentration of 1E3 and is then diminished by a higher concentration; it also has a biphasic response. Nuclear localization of NF-κB is affected by PI3K/Akt signaling, and DGC associated PI3K activity also shows a biphasic response to 1E3. Furthermore, our data suggest that activation of c-jun N-terminal kinase participates in the cell survival pathway and suggest that NF-κB is involved in both survival and cell death. A model is presented which incorporates these observations.
Elevated ammonium levels: differential acute effects on three glutamate transporter isoforms
Authors: Søgaard Rikke , Novak Ivana , MacAulay Nanna
Published: December 2011

Increased ammonium (NH4+/NH3) in the brain is a significant factor in the pathophysiology of hepatic encephalopathy, which involves altered glutamatergic neurotransmission. In glial cell cultures and brain slices, glutamate uptake either decreases or increases following acute ammonium exposure but the factors responsible for the opposing effects are unknown. Excitatory amino acid transporter isoforms EAAT1, EAAT2, and EAAT3 were expressed in Xenopus oocytes to study effects of ammonium exposure on their individual function. Ammonium increased EAAT1- and EAAT3-mediated [3H]glutamate uptake and glutamate transport currents but had no effect on EAAT2. The maximal EAAT3-mediated glutamate transport current was increased but the apparent affinities for glutamate and Na+ were unaltered. Ammonium did not affect EAAT3-mediated transient currents, indicating that EAAT3 surface expression was not enhanced. The ammonium-induced stimulation of EAAT3 increased with increasing extracellular pH, suggesting that the gaseous form NH3 mediates the effect. An ammonium-induced intracellular alkalinization was excluded as the cause of the enhanced EAAT3 activity because 1) ammonium acidified the oocyte cytoplasm, 2) intracellular pH buffering with MOPS did not reduce the stimulation, and 3) ammonium enhanced pH-independent cysteine transport. Our data suggest that the ammonium-elicited uptake stimulation is not caused by intracellular alkalinization or changes in the concentrations of cotransported ions but may be due to a direct effect on EAAT1/EAAT3. We predict that EAAT isoform-specific effects of ammonium combined with cell-specific differences in EAAT isoform expression may explain the conflicting reports on ammonium-induced changes in glial glutamate uptake.
Measuring mitochondrial respiration in intact single muscle fibers
Authors: Schuh Rosemary A. , Jackson Kathryn C. , Khairallah Ramzi J. , Ward Christopher W. , Spangenburg Espen E.
Published: December 2011

Measurement of mitochondrial function in skeletal muscle is a vital tool for understanding regulation of cellular bioenergetics. Currently, a number of different experimental approaches are employed to quantify mitochondrial function, with each involving either mechanically or chemically induced disruption of cellular membranes. Here, we describe a novel approach that allows for the quantification of substrate-induced mitochondria-driven oxygen consumption in intact single skeletal muscle fibers isolated from adult mice. Specifically, we isolated intact muscle fibers from the flexor digitorum brevis muscle and placed the fibers in culture conditions overnight. We then quantified oxygen consumption rates using a highly sensitive microplate format. Peak oxygen consumption rates were significantly increased by 3.4-fold and 2.9-fold by simultaneous stimulation with the uncoupling agent, carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP), and/or pyruvate or palmitate exposure, respectively. However, when calculating the total oxygen consumed over the entire treatment, palmitate exposure resulted in significantly more oxygen consumption compared with pyruvate. Further, as proof of principle for the procedure, we isolated fibers from the mdx mouse model, which has known mitochondrial deficits. We found significant reductions in initial and peak oxygen consumption of 51% and 61% compared with fibers isolated from the wild-type (WT) animals, respectively. In addition, we determined that fibers isolated from mdx mice exhibited less total oxygen consumption in response to the FCCP + pyruvate stimulation compared with the WT mice. This novel approach allows the user to make mitochondria-specific measures in a nondisrupted muscle fiber that has been isolated from a whole muscle.
Glucose sensing by gut endocrine cells and activation of the vagal afferent pathway is impaired in a rodent model of type 2 diabetes mellitus
Authors: Lee Jennifer , Cummings Bethany P. , Martin Elizabeth , Sharp James W. , Graham James L. , Stanhope Kimber L. , Havel Peter J. , Raybould Helen E.
Published: December 2011

Glucose in the gut lumen activates gut endocrine cells to release 5-HT, glucagon-like peptide 1/2 (GLP-1/2), and glucose-dependent insulinotropic polypeptide (GIP), which act to change gastrointestinal function and regulate postprandial plasma glucose. There is evidence that both release and action of incretin hormones is reduced in type 2 diabetes (T2D). We measured cellular activation of enteroendocrine and enterochromaffin cells, enteric neurons, and vagal afferent neurons in response to intestinal glucose in a model of type 2 diabetes mellitus, the UCD-T2DM rat. Prediabetic (PD), recent-diabetic (RD, 2 wk postonset), and 3-mo diabetic (3MD) fasted UCD-T2DM rats were given an orogastric gavage of vehicle (water, 0.5 ml /100 g body wt) or glucose (330 μmol/100 g body wt); after 6 min tissue was removed and cellular activation was determined by immunohistochemistry for phosphorylated calcium calmodulin-dependent kinase II (pCaMKII). In PD rats, pCaMKII immunoreactivity was increased in duodenal 5-HT ( P < 0.001), K ( P < 0.01) and L ( P < 0.01) cells in response to glucose; glucose-induced activation of all three cell types was significantly reduced in RD and 3MD compared with PD rats. Immunoreactivity for GLP-1, but not GIP, was significantly reduced in RD and 3MD compared with PD rats ( P < 0.01). Administration of glucose significantly increased pCaMKII in enteric and vagal afferent neurons in PD rats; glucose-induced pCaMKII immunoreactivity was attenuated in enteric and vagal afferent neurons ( P < 0.01, P < 0.001, respectively) in RD and 3MD. These data suggest that glucose sensing in enteroendocrine and enterochromaffin cells and activation of neural pathways is markedly impaired in UCD-T2DM rats.
Arousal from sleep in response to intermittent hypoxia in rat pups is modulated by medullary raphe GABAergic mechanisms
Authors: Darnall Robert A. , Schneider Robert W. , Tobia Christine M. , Zemel Benjamin M.
Published: December 2011

Arousal is an important defense against hypoxia during sleep. Rat pups exhibit progressive arousal impairment (habituation) with multiple hypoxia exposures. The mechanisms are unknown. The medullary raphe (MR) is involved in autonomic functions, including sleep, and receives abundant GABAergic inputs. We hypothesized that inhibiting MR neurons with muscimol, a GABAAreceptor agonist, or preventing GABA reuptake with nipecotic acid, would impair arousal and enhance arousal habituation and that blocking GABAAreceptors with bicuculline would enhance arousal and attenuate habituation. Postnatal day 15 (P15) to P25 rat pups were briefly anesthetized, and microinjections with aCSF, muscimol, bicuculline, or nipecotic acid were made into the MR. After a ∼30-min recovery, pups were exposed to four 3-min episodes of hypoxia separated by 6 min of normoxia. The time to arousal from the onset of hypoxia (latency) was determined for each trial. Latency progressively increased across trials (habituation) in all groups. The overall latency was greater after muscimol and nipecotic acid compared with aCSF, bicuculline, or noninjected controls. Arousal habituation was reduced after bicuculline compared with aCSF, muscimol, nipecotic acid, or noninjected pups. Increases in latency were mirrored by decreases in chamber [O2] and oxyhemoglobin saturation. Heart rate increased during hypoxia and was greatest in muscimol-injected pups. Our results indicate that the MR plays an important, not previously described, role in arousal and arousal habituation during hypoxia and that these phenomena are modulated by GABAergic mechanisms. Arousal habituation may contribute to sudden infant death syndrome, which is associated with MR serotonergic and GABAergic receptor dysfunction.
Navigation Behaviors Based on Fuzzy ArtMap Neural Networks for Intelligent Autonomous Vehicles
Authors: Chohra Amine , Azouaoui Ouahiba
Published: December 2011

The use of hybrid intelligent systems (HISs) is necessary to bring the behavior of intelligent autonomous vehicles (IAVs) near the human one in recognition, learning, adaptation, generalization, decision making, and action. First, the necessity of HIS and some navigation approaches based on fuzzy ArtMap neural networks (FAMNNs) are discussed. Indeed, such approaches can provide IAV with more autonomy, intelligence, and real-time processing capabilities. Second, an FAMNN‐based navigation approach is suggested. Indeed, this approach must provide vehicles with capability, after supervised fast stable learning: simplified fuzzy ArtMap (SFAM), to recognize both target‐location and obstacle‐avoidance situations using FAMNN1 and FAMNN2, respectively. Afterwards, the decision making and action consist of two association stages, carried out by reinforcement trial and error learning, and their coordination using NN3. Then, NN3 allows to decide among the five (05) actions to move towards 30∘, 60∘, 90∘, 120∘, and 150∘. Third, simulation results display the ability of the FAMNN‐based approach to provide IAV with intelligent behaviors allowing to intelligently navigate in partially structured environments. Finally, a discussion, dealing with the suggested approach and how its robustness would be if implemented on real vehicle, is given.
Deposition of Apatite on Carbon Nanofibers in Simulated Body Fluid
Authors: Taruta Seiichi , Kidokoro Kazuki , Yamakami Tomohiko , Yamaguchi Tomohiro , Kitajima Kunio , Endo Morinobu , Saito Naoto
Published: December 2011

Carbon nanofibers (CNFs) were soaked in 1.5 simulated body fluid (1.5 SBF) in which inorganic ion concentrations are 1.5 times as high as those in the standard SBF. The influence of the CNFs content in 1.5 SBF and pretreatment of the CNFs on the biomimetical deposition of apatite were investigated. The spherical bone-like apatite particles were deposited on the pristine CNFs soaked in 1.5 SBF. Amount of deposited apatite per a unit of CNFs increased with a decrease in the CNFs content in 1.5 SBF, and it decreased markedly when the CNFs were pretreated with concentrated sulfuric acid/nitric acid (3 : 1 v/v) mixture for longer periods. Such results suggest that too many nucleation sites of apatite, which were functional groups, such as carboxyl and hydroxyl groups, existed on the CNFs in the 1.5 SBF, and most embryos formed on the sites could not grow to critical nuclei and furthermore did not grow to apatite.
Quasi‐Sliding Mode Control of Chaos in Permanent Magnet Synchronous Motor
Authors: Huang Cheng-Fang , Lin Jui-Sheng , Liao Teh-Lu , Chen Chih-Yung , Yan Jun-Juh
Published: December 2011

A quasi‐sliding mode control (QSMC) to suppress chaos for a permanent magnet synchronous motor (PMSM) with parameters fall into a certain area is proposed in this paper. Especially, based on the new concept of QSMC, continuous control input is obtained to avoid chattering phenomenon. As expected, the system states can be driven to zero or into a predictable and adjustable bound even when uncertainties are present. Numerical simulations demonstrate the validity of the proposed QSMC design method.
Electrochemical Fabrication of Shape‐Controlled Copper Hierarchical Structures Assisted by Surfactants
Authors: Dong Huaping , Wang Yajun , Tao Feifei , Wang Linxia
Published: December 2011

Various copper hierarchical structures assisted by surfactants were successfully fabricated combined with the electrodeposition technique. To the best of our knowledge, it is the first report on the controlled synthesis of metal copper hierarchical structures. All of the products synthesized in the presence and absence of surfactants, such as cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), or polyvinylpyrrolidone (PVP), were face‐centered cubic copper, characterized by X‐ray diffraction (XRD), indicating the surfactant‐independent crystal structure. However, supplementing surfactants is helpful to construct hierarchical structures and exerts an important influence on copper morphologies. The absence of surfactants led to the formation of the nubby structures, while the use of surfactants resulted in the synthesis of the flower, dendrite, and sphere‐like hierarchical morphologies. The effect of deposition time on the copper morphologies was investigated by scanning electron microscopy (SEM), and the possible formation mechanism of the copper hierarchical structures with various morphologies was discussed.
A New Lycid Genus from the Dominican Amber (Insecta, Coleoptera, Lycidae, Leptolycinae, Leptolycini)
Authors: Kazantsev Sergey V.
Published: December 2011

A new fossil genus,Electropteron  gen.n., and a new species,E. avus  sp.n., are described from the Dominican Amber.Electropteron avus  gen.n.,sp.n., appears to be related to some of the extant Great Antillean lycids and is the first fossil taxon from the subfamily Leptolycinae.