bluuebunny/crossref_metadata_2025 huggingface dataset:
Technische Chemie 2008
Authors: Brüggemann Oliver , Busch Markus , Wolf Dorit
Published: May 2009

Bestimmendes Thema sowohl in der klassischen als auch in der biokatalytischen Chemie ist die Effizienzsteigerung, etwa bei neuen Katalysatoren, Reaktoren oder Prozessen. Dabei geht es um Verfahren, die Wasserstoff erzeugen oder Biomasse verwerten.
Application of variational iteration method for modified Camassa‐Holm and Degasperis‐Procesi equations
Authors: Jafari H. , Zabihi M. , Salehpoor E.
Published: May 2009

In this article, the variational iteration method (VIM) is used to obtain approximate analytical solutions of the modified Camassa‐Holm and Degasperis‐Procesi equations. The method is capable of reducing the size of calculation and easily overcomes the difficulty of the perturbation technique or Adomian polynomials. The results reveal that the VIM is very effective. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010
Plasma Process. Polym. 5/2009
Authors: Végh Joseph J. , Graves David B.
Published: May 2009

Cover: The image shows a molecular dynamics visualization of an argon ion impact trajectory into the near‐surface damaged layer of polystyrene during steady‐state physical sputtering. Further details can be found in the article by J. J. Végh and D. B. Graves* on page 320.
Interaction and conformational dynamics of membrane‐spanning protein helices
Authors: Langosch Dieter , Arkin Isaiah T.
Published: May 2009

Within 1 or 2 decades, the reputation of membrane‐spanning α‐helices has changed dramatically. Once mostly regarded as dull membrane anchors, transmembrane domains are now recognized as major instigators of protein–protein interaction. These interactions may be of exquisite specificity in mediating assembly of stable membrane protein complexes from cognate subunits. Further, they can be reversible and regulatable by external factors to allow for dynamic changes of protein conformation in biological function. Finally, these helices are increasingly regarded as dynamic domains. These domains can move relative to each other in different functional protein conformations. In addition, small‐scale backbone fluctuations may affect their function and their impact on surrounding lipid shells. Elucidating the ways by which these intricate structural features are encoded by the amino acid sequences will be a fascinating subject of research for years to come.
Integrity of N‐ and C‐termini is important for E. coli Hsp31 chaperone activity
Authors: Sastry M. S. R. , Zhou Weibin , Baneyx François
Published: May 2009

Hsp31 is a stress‐inducible molecular chaperone involved in the management of protein misfolding at high temperatures and in the development of acid resistance in starved E. coli. Each subunit of the Hsp31 homodimer consists of two structural domains connected by a flexible linker that sits atop a continuous tract of nonpolar residues adjacent to a hydrophobic bowl defined by the dimerization interface. Previously, we proposed that while the bowl serves as a binding site for partially folded species at physiological temperatures, chaperone function under heat shock conditions requires that folding intermediates further anneal to high‐affinity binding sites that become uncovered upon thermally induced motion of the linker. In support of a mechanism requiring that client proteins first bind to the bowl, we show here that fusion of a 20‐residue‐long hexahistidine tag to the N‐termini of Hsp31 abolishes chaperone activity at all temperatures by inducing reversible structural changes that interfere with substrate binding. We further demonstrate that extending the C‐termini of Hsp31 with short His tags selectively suppresses chaperone function at high temperatures by interfering with linker movement. The structural and functional sensitivity of Hsp31 to lengthening is consistent with the high degree of conservation of class I Hsp31 orthologs and will serve as a cautionary tale on the implications of affinity tagging.
Bioassay‐guided isolation of apigenin with GABA‐benzodiazepine activity from Tanacetum parthenium
Authors: Jäger A. K. , Krydsfeldt K. , Rasmussen H. B.
Published: May 2009

Extracts of Tanacetum parthenium are used in the prophylactic treatment of migraine and have also been used in Danish folk medicine for the treatment of epilepsy. An ethanol extract of T. parthenium showed high affinity for the GABAA‐benzodiazepine site. An ethanol extract of T. parthenium was fractionated by VLC on silica and preparative C18 HPLC. Each step was monitored with the GABAA‐benzodiazepine bioassay. The fractionation led to the isolation of apigenin, which may be responsible for CNS‐effects of T. parthenium extracts. Copyright © 2009 John Wiley & Sons, Ltd.
Medicinal use of potato‐derived products: a systematic review
Authors: Vlachojannis J. E. , Cameron M. , Chrubasik S.
Published: May 2009

In the traditional medicine of Europe, raw potatoes are used for gastrointestinal disorders, and topical potato preparations as a hot pack for pain or for softening furuncles. The aim of this study was to review the literature and summarize the data on the medicinal use of potato‐derived products. Several databases and other sources were searched to identify clinical trials investigating potato‐derived preparations. The trials were analysed for quality. Five trials were identified; two open uncontrolled studies, two open controlled studies and one double‐blind study. These results stimulate further investigation of oral potato juice concentrate in patients with dyspeptic complaints, of potato proteinase inhibitor II for weight reduction, and of topical potato proteins for preventing protease‐induced perianal dermatitis. We recommend that future studies have a confirmatory design. Copyright © 2009 John Wiley & Sons, Ltd.
Corosolic acid stimulates osteoblast differentiation by activating transcription factors and MAP kinases
Authors: Shim Ki Shuk , Lee Su‐Ui , Ryu Shi Yong , Min Yong Ki , Kim Seong Hwan
Published: May 2009

Recently, the use of anabolic agents to enhance bone mass has been a source of interest. Previous work by us suggested that corosolic acid (2α‐hydroxyursolic acid), an active component of banaba leaves (Lagerstroemia speciosa L.), potentially stimulates the differentiation of mouse osteoblasts. Therefore, the present study investigated whether corosolic acid stimulates osteoblast differentiation, and its possible mechanisms of action. At low concentrations (up to 5 µm), corosolic acid significantly stimulated osteoblast differentiation and mineralization without cytotoxicity. Corosolic acid induced NF‐κB and MAP kinase activity at an early stage of osteoblast differentiation and increased the activity of the transcription factor AP‐1 during late‐stage osteoblast differentiation. These results suggest that the anabolic effects of corosolic acid upon osteoblast differentiation could result from its activation of transcription factors and MAP kinases. Copyright © 2009 John Wiley & Sons, Ltd.
Total cluster energy calculation of lithium ion conductors by the DV‐Xα method
Authors: Kowada Y. , Nishitani W. , Ogasawara K.
Published: May 2009

Recently, several programs for the total cluster energy calculation have been developed in the DV‐Xα method. In this study, we have calculated and compared total cluster energies of several diatomic molecules and model clusters of ionic conductors. The total cluster energies of diatomic molecules are minimum near the equilibrium atomic distance of each molecule though the absolute value of the total cluster energy was slightly different from each other. In the case of the model cluster of the Li3N crystal, which is one of the typical Li ion conductors, we have obtained the energy change as a function of the site during the movement of a Li ion. The energy change with the movement of the Li ion along the conduction path was considerably smaller than along other paths, consistent with the results by the band calculation and experiments. The total cluster energy calculation method was useful enough for the discussion of the cluster energy. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Systems for mobile broadcast
Authors: Reimers Ulrich H.
Published: May 2009

The paper presents an overview of the systems for mobile broadcast which have been deployed today or are under development. Two examples are explained in some detail, namely DVB‐H and DVB‐SH. In addition, the need of ‘higher layer’ solutions is identified and IP Datacast is briefly explained. Copyright © 2009 John Wiley & Sons, Ltd.
Chemical Redox Modulation of the Surface Chemistry of CdTe Quantum Dots for Probing Ascorbic Acid in Biological Fluids
Authors: Chen Ying‐Jun , Yan Xiu‐Ping
Published: May 2009

Most of the fluorescence resonance energy transfer (FRET)‐based sensors employing quantum dots (QDs) usually use organic fluorophores and gold nanoparticles as the quenchers. However, complex processes for the modification/immobilization of the QDs are always necessary, as the generation of FRET requires strict distance between the donor and acceptor. Herein, a simple chemical redox strategy for modulating the surface chemistry of the QDs to develop a QD‐based turn‐on fluorescent probe is reported. The principle of the strategy is demonstrated by employing CdTe QDs with KMnO4 as the quencher and ascorbic acid as the target analyte. The fluorescence of CdTe QDs is quenched with a blue‐shift upon addition of KMnO4 due to the oxidation of the Te atoms on the surface of the QDs. The quenched fluorescence of the QDs is then recovered upon addition of ascorbic acid due to the reduction of CdTeO3/TeO2 on the surface of the QDs to CdTe. The recovered fluorescence of the QDs increases linearly with the concentration of ascorbic acid from 0.3 to 10 µM. Thus, a novel QD‐based turn‐on fluorescent probe with a detection limit as low as 74 nM is developed for the sensitive and selective detection of ascorbic acid in biological fluids. The present approach avoids the complex modification/immobilization of the QDs involved in FRET‐based sensors, and opens a simple pathway to developing cost‐effective, sensitive, and selective QD‐based fluorescence turn‐on sensors/probes for biologically significant antioxidants.
Beleuchtung von Arbeitsstätten durch Dachoberlichter
Authors: Cornelius Wolfgang
Published: May 2009

Dieser Beitrag befasst sich mit der Beleuchtung von Arbeitsstätten und hier insbesondere mit natürlichem Tageslicht durch Dachoberlichter. Es werden sowohl die beleuchtungstechnischen Anforderungen durch den Gesetzgeber und andere Rechtsnormensetzer geschildert, als auch die normative Seite angesprochen. Neben den besonderen Vorteilen des Tageslichtes zu Beleuchtungszwecken wird die Planung der Beleuchtung mit Dachoberlichtern auch unter Zuhilfenahme von Faustformeln erläutert. Abschließend werden neue EDV‐technische Planungstools vorgestellt.

Lighting of work places by rooflights.

This contribution deals with the lighting of work places and especially with daylight by rooflights. The lighting engineering requirements by legislation and other legal norm setter as well as the standardization point of view were described. Besides the particular advantages of daylight for lighting purposes this contribution gives instructions for the planning of lighting by rooflights also by using rules of thumb. Finally new software design tools were presented.
Steady and Dynamic Shear Rheology of Fucoidan‐Buckwheat Starch Mixtures
Authors: Cho MyoungLae , Choi Won‐Seok , You SangGuan
Published: May 2009

Rheological properties of fucoidan (F) and buckwheat starch (B) mixtures (3% or 6%) at different blending ratios of fucoidans (0, 0.1, 0.2, 0.5 and 1.0%) were investigated in steady and dynamic shear. Steady shear viscosity measurement revealed that aqueous pastes of the BF blends (3%, w/v) had a pseudoplastic and shear‐thinning behavior with flow behavior index (n) values of 0.61–0.68. The substitution of starch with fucoidan polymers significantly lowered the apparent viscosities compared with the pure starch paste and, when mixed with less than 0.5% of fucoidan, the viscosities of the pastes were even lower than those of the starch pastes at the corresponding starch concentrations. According to dynamic viscoelastic measurement performed at 6% total carbohydrate concentration, buckwheat starch mixtures behaved like weak gels and the BF blends containing less than 0.5% fucoidan had considerably lower storage (G') and loss (G') moduli than the starch paste at the corresponding starch concentrations. However, the magnitude of G' increased with fucoidan concentrations over 0.5%, suggesting that a concentration of fucoidans > 0.5% might enhance the formations of three‐dimensional networks and crosslinking of the starch samples, probably because of the mutual exclusion between starch and fucoidan polymers through the phase separation process. This study indicates that it is possible to obtain the BF blends having various rheological properties by changing the concentration of fucoidan polymers.
Misplaced intrauterine contraceptive device
Authors: Katesmark Mike , Chapman Natasha
Published: May 2009

The authors describe the case of a woman who presented with pelvic pain following insertion of an intrauterine system by her GP, and was found to have a uterine perforation. This is an uncommon but recognised complication of intrauterine devices. Copyright © 2009 Wiley Interface Ltd
Does tubal ectopic pregnancy with hemoperitoneum always require surgery?
Authors: Bignardi T. , Condous G.
Published: May 2009

Objective

Hemoperitoneum is accepted as an indication for surgery in women with tubal ectopic pregnancy. The aim of this pilot study was to evaluate the feasibility of managing such women non‐surgically.

Methods

This was a prospective observational study. Women with tubal ectopic pregnancy and hemoperitoneum detected on transvaginal sonography (TVS) were managed as inpatients either expectantly or with methotrexate (MTX). Inclusion criteria for conservative management were: compliance, clinical stability, absence of acute abdomen, stable hemoglobin level on two measurements (0 and 12–24 h apart), serum human chorionic gonadotropin (hCG) < 5000 IU/L, absence of fetal cardiac activity on TVS and absence of significant hemoperitoneum, defined as blood above the level of the uterine fundus and/or in Morison's pouch (hepatorenal space). Subsequent management was based upon the hCG ratio at 48 h. All the women were managed as inpatients until the abdominal pain settled and the serum hCG levels were falling.

Results

Forty‐one women with tubal ectopic pregnancy presented between November 2006 and March 2008. Eight women (20%) fulfilled the entry criteria. The median gestational age at diagnosis was 49 (interquartile range, 38–52.5) days. All women presented with lower abdominal pain/right iliac fossa or left iliac fossa pain. Hemoglobin levels ranged from 11.2 to 14.2 g/dL at presentation and from 12.0 to 14.8 g/dL after 12–24 h. 6/8 (75%) women were managed expectantly and 2/8 (25%) received MTX. All women had resolution of their ectopic pregnancy within 3 weeks with no complications.

Conclusions

This pilot study suggests that the finding of hemoperitoneum on ultrasound examination may not be an absolute contraindication to conservative management of tubal ectopic pregnancy. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Hierarchical location service for wireless sensor networks with mobile sinks
Authors: Yan Yan , Zhang Baoxian , Zheng Jun , Ma Jian
Published: May 2009

In wireless sensor networks (WSNs), a mobile sink can help eliminate the hotspot effect in the vicinity of the sink, which can balance the traffic load in the network and thus improve the network performance. Location‐based routing is an effective routing paradigm for supporting sink mobility in WSNs with mobile sinks (mWSNs). To support efficient location‐based routing, scalable location service must be provided to advertise the location information of mobile sinks in an mWSN. In this paper, we propose a new hierarchical location service for supporting location‐based routing in mWSNs. The proposed location service divides an mWSN into a grid structure and exploits the characteristics of static sensors and mobile sinks in selecting location servers. It can build, maintain, and update the grid‐spaced network structureviaa simple hashing function. To reduce the location update cost, a hierarchy structure is built by choosing a subset of location servers in the network to store the location information of mobile sinks. The simulation results show that the proposed location service can significantly reduce the communication overhead caused by sink mobility while maintaining high routing performance, and scales well in terms of network size and sink number. Copyright © 2009 John Wiley & Sons, Ltd.
Nanoparticles for photoacoustic imaging
Authors: Yang Xinmai , Stein Erich W. , Ashkenazi S. , Wang Lihong V.
Published: May 2009

Nanoparticles have been designed and applied as contrast enhancers in various optical imaging techniques, such as optical coherence tomography, fluorescence imaging, and optical reflectance microscopy. As an emerging hybrid imaging modality, photoacoustic imaging (PAI) has also benefited from the application of these nanoparticle‐based contrast agents. We review this rapidly growing field and describe the applications of nanoparticles in PAI. Particular focus is given to nanoparticles whose absorption mechanism is based on surface plasmon resonance, including gold nanoshells, nanorods, and nanocages. Dye‐embedded nanoparticles are also reviewed. Specifically, the design and application of each nanoparticle‐based contrast agent in relation to the field of PAI are detailed. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Diagnostic Tools > In Vivo Nanodiagnostics and Imaging
Phase Transition of Rubidium Lead Tetrathiophosphate RbPbPS4
Authors: Belkyal Imane , El Azhari Mohamed , Wu Yuandong , Bensch Wolfgang , Depmeier Wulf
Published: May 2009

The single crystal structure of RbPbPS4 was determined at 293 K. The compound crystallizes in the orthorhombic space group Pnma (No. 62) with a = 17.486(1) Å, b = 6.7127(5) Å, c = 6.4191(5) Å, V = 753.5(1) Å3, Z = 4. Differential scanning calorimetry shows a reversible structural phase transition at 182 K on cooling and at 184 K on heating. The phase transition is attributed to the displacement of the lead atoms which are located on the mirror planes at room temperature. In the low temperature modification, the Pb2+ ions are moved away from the mirror plane thus changing the coordination number from seven at low temperature to six at room temperature. The low temperature phase of RbPbPS4 is non‐centrosymmetric with space group P212121, which is a maximal translationengleiche subgroup index 2 (t2) of Pnma. The analysis demonstrates that the phase transition is of second order, or at least nearly so.
Evaluation of cholecystic venous flow using indocyanine green fluorescence angiography
Authors: Kai Kyohei , Satoh Shizou , Watanabe Takanori , Endo Yoshikatsu
Published: May 2009

Background/purpose

The cholecystic veins are thought to be an important metastatic route of gallbladder carcinoma to the liver. In the present study we evaluated the cholecystic venous drainage area, utilizing a novel method, indocyanine green (ICG) fluorescence angiography after superselective catheterization of the cholecystic artery, to detect and elucidate cholecystic venous flow.

Methods

Cannulation of the cholecystic artery was performed under laparotomy in nine patients who required a cholecystectomy. After ICG injection into the cholecystic artery, the cholecystic venous flow images were visualized with a near‐infrared camera system and were analyzed according to site, shape, and time of fluorescence.

Results

Fluorescence images of the cholecystic venous flow could be viewed as real‐time images in all patients. We demonstrated that the route of the cholecystic venous flow could be classified into two patterns: type 1, in which the cholecystic veins flowed directly into the hepatic parenchyma adjacent to the gallbladder; and type 2, in which the veins flowed into sites separate from the gallbladder. In the type 1 pattern, fluorescence was observed in segment (S; defined according to Couinaud's nomenclature) 4a or S5 adjacent to the gallbladder in all cases. On the other hand, in the type‐2 pattern, fluorescence was observed in S4a (6/9), S5 (8/9), S4b (2/9), S3 (2/9), S1 (1/9), S2 (1/9), and S8 (1/9) distant from the gallbladder. Overall, two‐thirds of the cases showed fluorescence in segments other than S4a or S5.

Conclusions

Indocyanine green (ICG) fluorescence angiography is considered to be a useful method to detect and elucidate cholecystic venous flow in real time. This study showed that the cholecystic venous flow spread to the liver through two different pathways, one that flowed directly into the hepatic parenchyma adjacent to the gallbladder, while the other flowed into sites separate from the gallbladder. Taking these findings into consideration, we may therefore need to reconsider the preventive effects of a hepatic resection.
Development of E‐Info Geneca: A Website Providing Computer‐Tailored Information and Question Prompt Prior to Breast Cancer Genetic Counseling
Authors: Albada Akke , van Dulmen Sandra , Otten Roel , Bensing Jozien M. , Ausems Margreet G. E. M.
Published: May 2009

This article describes the stepwise development of the website ‘E‐info geneca’. The website provides counselees in breast cancer genetic counseling with computer‐tailored information and a question prompt prior to their first consultation. Counselees generally do not know what to expect from genetic counseling and they tend to have a passive role, receiving large amounts of relatively standard information. Using the “intervention mapping approach,” we developed E‐info geneca aiming to enhance counselees’ realistic expectations and participation during genetic counseling. The information on this website is tailored to counselees’ individual situation (e.g., the counselee's age and cancer history). The website covers the topics of the genetic counseling process, breast cancer risk, meaning of being a carrier of a cancer gene mutation, emotional consequences and hereditary breast cancer. Finally, a question prompt encourages counselees to prepare questions for their genetic counseling visit.
Identification of gene biomarkers for respiratory syncytial virus infection in a bronchial epithelial cell line
Authors: Huang Yuh-Chin T. , Li Zhuowei , Hyseni Xhevahire , Schmitt Michael , Devlin Robert B. , Karoly Edward D. , Soukup Joleen M.
Published: May 2009

Respiratory syncytial virus (RSV) infection involves complex virus-host interplay. In this study, we analyzed gene expression in RSV-infected BEAS-2B cells to discover novel signaling pathways and biomarkers. We hybridized RNAs from RSV- or vehicle-treated BEAS-2B to Affymetrix HU133 plus 2.0 microarrays (n = 4). At 4 and 24 h post-infection, 277 and 900 genes (RSV/control ratio ≥2.0 or ≤0.5), and 1 and 12 pathways respectively were significantly altered. Twenty-three and 92 genes at 4 and 24 h respectively matched respiratory disease biomarkers with ARG2 flagged at 24 h and SCNN1G, EPB41L4B, CSF1, PTEN, TUBB1 and ESR2 at both time points. Hierachical clustering showed a cluster containing ARG2 and IL8. In human bronchial epithelial cells, RSV upregulated arginase II protein. Knockdown of ARG2 increased RSV-induced IL-8, LDH and histone release. With microarray, we identified novel proximal airway epithelial cell genes that may be tested in the sputum samples as biomarkers of RSV infection.
Pulsed-Laser-Induced Simple Synthetic Route for Tb3Al5O12:Ce3+Colloidal Nanocrystals and Their Luminescent Properties
Authors: Mhin SungWook , Ryu JeongHo , Kim KangMin , Park GyeongSeon , Ryu HanWool , Shim KwangBo , Sasaki Takeshi , Koshizaki Naoto
Published: May 2009

Cerium-doped Tb3Al5O12(TAG:Ce3+) colloidal nanocrystals were synthesized by pulsed laser ablation (PLA) in de-ionized water and lauryl dimethylaminoacetic acid betain (LDA) aqueous solution for luminescent bio-labeling application. The influence of LDA molecules on the crystallinity, crystal morphology, crystallite size, and luminescent properties of the prepared TAG:Ce3+colloidal nanocrystals was investigated in detail. When the LDA solution was used, smaller average crystallite size, narrower size distribution, and enhanced luminescence were observed. These characteristics were explained by the effective role of occupying the oxygen defects on the surface of TAG:Ce3+colloidal nanocrystal because the amphoteric LDA molecules were attached by positively charged TAG:Ce3+colloidal nanocrystals. The blue-shifted phenomena found in luminescent spectra of the TAG:Ce3+colloidal nanocrystals could not be explained by previous crystal field theory. We discuss the 5d energy level of Ce3+with decreased crystal size with a phenomenological model that explains the relationship between bond distance with 5d energy level of Ce3+based on the concept of crystal field theory modified by covalency contribution.
A functional polymorphism of the brain derived neurotrophic factor gene and cortical anatomy in autism spectrum disorder
Authors: Raznahan Armin , Toro Roberto , Proitsi Petra , Powell John , Paus Tomas , F. Bolton Patrick , Murphy Declan G. M.
Published: May 2009

Autism Spectrum Disorder (ASD) is associated with both (i) post-mortem and neuroimaging evidence of abnormal cortical development, and (ii) altered signalling in Brain Derived Neurotrophic Factor (BDNF) pathways - which regulate neuroproliferative and neuroplastic processes. In healthy controls genotype at a single nucleotide polymorphism that alters BDNF signalling (Val66met) has been related to regional cortical volume. It is not known however if this influence on brain development is intact in ASD. Therefore we compared the relationship between genotype and cortical anatomy (as measured using in vivo Magnetic Resonance Imaging) in 41 people with ASD and 30 healthy controls. We measured cortical volume, and its two sole determinants - cortical thickness and surface area - which reflect differing neurodevelopmental processes. We found “Group-by-Genotype” interactions for cortical volume in medial (caudal anterior cingulate, posterior cingulate) and lateral (rostral middle, lateral orbitofrontal, pars orbitalis and pars triangularis) frontal cortices. Furthermore, within (only) these regions “Group-by-Genotype” interactions were also found for surface area. No effects were found for cortical thickness in any region. Our preliminary findings suggest that people with ASD have differences from controls in the relationship between BDNF val66met genotype and regional (especially frontal) cortical volume and surface area, but not cortical thickness. Therefore alterations in the relationship between BDNF val66met genotype and surface area in ASD may drive the findings for volume. If correct, this suggests ASD is associated with a distorted relationship between BDNF val66met genotype and the determinants of regional cortical surface area – gyrification and/or sulcal positioning.
Cholesterol Synthesis Inhibitor U18666A and the Role of Sterol Metabolism and Trafficking in Numerous Pathophysiological Processes
Authors: Cenedella Richard J.
Published: May 2009

The multiple actions of U18666A have enabled major discoveries in lipid research and contributed to understanding the pathophysiology of multiple diseases. This review describes these advances and the utility of U18666A as a tool in lipid research. Harry Rudney's recognition that U18666A inhibited oxidosqualene cyclase led him to discover a pathway for formation of polar sterols that he proved to be important regulators of 3‐hydroxy‐3‐methyl‐glutaryl coenzyme A reductase. Laura Liscum's recognition that U18666A inhibited the egress of cholesterol from late endosomes and lysosomes led to greatly improved perspective on the major pathways of intracellular cholesterol trafficking. The inhibition of cholesterol trafficking by U18666A mimicked the loss of functional Niemann–Pick type C protein responsible for NPC disease and thus provided a model for this disorder. U18666A subsequently became a tool for assessing the importance of molecular trafficking through the lysosomal pathway in other conditions such as atherosclerosis, Alzheimer's disease, and prion infections. U18666A also provided animal models for two important disorders: petite mal (absence) epilepsy and cataracts. This was the first chronic model of absence epilepsy. U18666A is also being used to address the role of oxidative stress in apoptosis. How can one molecule have so many effects? Perhaps because of its structure as an amphipathic cationic amine it can interact and inhibit diverse proteins. Restricting the availability of cholesterol for membrane formation through inhibition of cholesterol synthesis and intracellular trafficking could also be a mechanism for broadly affecting many processes. Another possibility is that through intercalation into membrane U18666A can alter membrane order and therefore the function of resident proteins. The similarity of the effects of natural and enantiomeric U18666A on cells and the capacity of intercalated U18666A to increase membrane order are arguments in favor of this possibility.
Anomalies génétiques et infertilité masculine
Authors: Vialard F. , Mandon-Pépin B. , Pellestor F. , Ziyyat A. , Albert M. , Molina-Gomes D. , Selva J. , Fellous M.
Published: May 2009

Environ 15 % des couples sont confrontés à une infertilité. Dans la moitié des cas, la cause est masculine. Quatre-vingt-dix pour cent des causes d’infertilité chez l’homme ne sont toujours pas élucidées, certaines seraient dues à des causes génétiques ou environnementales ou les deux, impliquant alors des gènes de susceptibilité à caractériser. Les anomalies génétiques ont été recherchées par trois approches: 1) cytogénétique, surtout grace au progrès de la cytogénétique moléculaire et l’analyse directe des gamètes par la technique d’hybridation moléculaire in situ. La découverte d’une anomalie chromosomique, cause la plus fréquente des infertilités (y compris la délétion de l’Y), ne permet pas facilement de faire la distinction entre une anomalie génique impliquée dans le remaniement et une anomalie mécanique intrinsèque de la méiose; 2) l’analyse de gènes candidats utilise souvent les données obtenues dans les modèles animaux et principalement murins. Cette approche, très souvent utilisée dans la littérature, s’avère souvent longue, coûteuse et l’on découvre rarement une anomalie génique; c’est le cas par exemple des gènes de méiose; 3) l’approche mendélienne est évidemment l’approche de choix, en étudiant les cas familiaux d’infertilité qui sont plus fréquents que nous le pensons.
Les gangrènes des organes génitaux externes: à propos de 102 cas
Authors: Fall B. , Fall P. A. , Diao B. , Kpatcha M. R. , Sow Y. , Kabore F. A. , Ali M. , Ndoye A. K. , Ba M. , Diagne B. A.
Published: May 2009

Buts

Rapporter les aspects épidémiologiques, cliniques, biologiques et thérapeutiques d’une série de 102 cas de gangrènes pénoscrotales et périnéales et en identifier les facteurs pronostiques.

Matériel et méthodes

Nous avons effectué une étude rétrospective colligeant 102 cas de gangrènes pénoscrotales et périnéales, admis au service d’urologie-andrologie du CHU Aristide-Le-Dantec de Dakar, entre janvier 2001 et décembre 2007.

Résultats

L’âge moyen de nos patients était de 50,0 ± 15,7 ans (extrêmes: 20–93 ans). La durée moyenne d’hospitalisation était de 8,0 ± 7,1 jours (extrêmes: 1–33 jours). Les lésions intéressaient le scrotum dans 61,8 % des cas, le scrotum et la verge dans 17,6 % des cas et la verge isolément dans 3,9 % des cas. Le périnée était atteint dans 14,7 % des cas. Il s’agissait d’une gangrène de Fournier (idiopathique) dans 26 cas (25,5 %) et d’une gangrène secondaire, à rétrécissement urétral, dans 70 cas (68,6 %). Les principaux facteurs de comorbidité associés étaient le diabète non insulinodépendant (13,7 %), l’hypertension artérielle (HTA) [5,9 %] et l’insuffisance rénale chronique (5,9 %). À la biologie, 79,4 % des patients avaient une concentration de leucocytes supérieure à 12 000/ml. Le taux d’hémoglobine était en moyenne de 9,8 ± 2,8 g/dl (extrêmes: 3,3–13,9 g/dl). L’antibiothérapie la plus utilisée associait une céphalosporine de troisième génération, un aminoside et la métronidazole (46,1 %). Les principaux gestes chirurgicaux réalisés ont été un débridement dans 21 cas (20,6 %), un débridement plus cystostomie dans 81 cas (79,4 %). Le taux de mortalité était de 15,7 %. Les principaux facteurs de mauvais pronostic chez nos patients étaient l’age, le caractère secondaire de la gangrène, l’étendue des lésions et l’association à un diabète et/ou à une HTA.

Conclusion

La gangrène des organes génitaux externes et du périnée reste une affection fréquente et grave. Son traitement doit être multidisciplinaire.
Évolution de la composante lipidique de la membrane plasmique des spermatozoïdes durant la maturation épididymaire
Authors: Rejraji H. , Saez F. , Drevet J. -R.
Published: May 2009

Un des aspects de la maturation posttesticulaire des spermatozoïdes chez les mammifères est l’évolution progressive de la composition lipidique de la membrane plasmique des gamètes males qui permet à ces derniers d’acquérir des capacités fusogènes particulières déterminantes pour la fécondation. Une part importante de cette modification du contenu lipidique de la membrane des gamètes males est assurée lors de la descente des spermatozoïdes dans le tubule épididymaire. Les mouvements lipidiques seront ensuite poursuivis dans les voies génitales femelles au cours d’un processus dynamique, la capacitation, étape préalable indispensable à la réaction acrosomique, et donc, à la fécondation. Cette revue fait l’état des lieux des connaissances acquises par divers groupes de recherche dans le premier volet épididymaire de la maturation lipidique des gamètes males dans différents modèles de mammifères.
Role of RVM neurons in capsaicin‐evoked visceral nociception and referred hyperalgesia
Authors: Sanoja Raul , Tortorici Victor , Fernandez Carlos , Price Theodore J. , Cervero Fernando
Published: May 2009

Most forms of visceral pain generate intense referred hyperalgesia but the mechanisms of this enhanced visceral hypersensitivity are not known. The on‐cells of the rostral ventromedial medulla (RVM) play an important role in descending nociceptive facilitation and can be sensitized to somatic mechanical stimulation following peripheral nerve injury or hindpaw inflammation. Here we have tested the hypothesis that visceral noxious stimulation sensitizes RVM ON‐like cells, thus promoting an enhanced descending facilitation that can lead to referred visceral hyperalgesia. Intracolonic capsaicin instillation (ICI) was applied to rats in order to create a hyperalgesic state dependent on noxious visceral stimulation. This instillation produced acute pain‐related behaviors and prolonged referred hyperalgesia that were prevented by the RVM microinjection of AP5, an NMDA selective antagonist. In electrophysiological experiments, ON‐like RVM neurons showed ongoing spontaneous activity following ICI that lasted for and an enhanced responsiveness to von Frey and heat stimulation of the hindpaw and to colorectal distention (CRD) that lasted for at least 50 min post capsaicin administration. Moreover, ON‐like cells acquired a novel response to CRD and responded to heat stimulation in the innocuous range. OFF‐like neurons responded to capsaicin administration with a brief (<5 min) inhibition of activity followed by an enhanced inhibition to noxious stimulation and a novel inhibition to innocuous stimulation (CRD and heat) at early time points (10 min post capsaicin). These results support the hypothesis that noxious visceral stimulation may cause referred hypersensitivity by promoting long‐lasting sensitization of RVM ON‐like cells.
The potential role of phrenic nucleus glutamate receptor subunits in mediating spontaneous crossed phrenic activity in neonatal rat
Authors: Huang Yonglu , Goshgarian Harry G.
Published: May 2009

Cervical spinal cord hemisection rostral to the phrenic nucleus leads to paralysis of the ipsilateral hemidiaphragm in adult rats. Respiratory function can be restored to the paralyzed hemidiaphragm by activating a latent respiratory motor pathway. The latent pathway is called the crossed phrenic pathway. In adult rats, the pathway can be activated by drug‐induced upregulation of NMDA receptor NR2A subunit and AMPA receptor GluR1 subunit in the phrenic nucleus following hemisection. In neonatal rats, this pathway is not latent as shown by the spontaneous expression of activity in the ipsilateral hemidiaphragm following hemisection. We hypothesized that the NR2A and GluR1 subunits may be highly expressed naturally on phrenic motoneurons of neonatal rats and may play a potential role in mediating the spontaneous expression of activity in the ipsilateral hemidiaphragm after hemisection. To test this hypothesis, the protein levels of NR2A and GluR1 in different age rats were assessed via Western blot analysis immediately following C2 hemisection and EMG recording of crossed phrenic activity. The protein levels of NR2A and GluR1 were transiently high in postnatal day 2 (P2) rats and then was significantly reduced in P7 and P35 animals. An immunofluorescence study qualitatively supported these findings. The present results indicate that the developmental downregulation of the phrenic nucleus glutamate receptor subunits correlates with the conversion of the crossed phrenic pathway in older postnatal animals from an active state to a latent state.
The Testing Effect and the Retention Interval
Authors: Toppino Thomas C. , Cohen Michael S.
Published: May 2009

People learn from tests. Providing tests often enhances retention more than additional study opportunities, but is this testing effect mediated by processes related to retrieval that are fundamentally different from study processes? Some previous studies have reported that testing enhances retention relative to additional studying, but only after a relatively long retention interval. To the extent that this interaction with retention interval dissociates the effects of studying and testing, it may provide crucial evidence for different underlying processes. However, these findings can be questioned because of methodological differences between the study and the test conditions. In two experiments, we eliminated or minimized the confounds that rendered the previous findings equivocal and still obtained the critical interaction. Our results strengthen the evidence for the involvement of different processes underlying the effects of studying and testing, and support the hypothesis that the testing effect is grounded in retrieval-related processes.
Observations of the Aleutian North Slope Current, Bering Sea, 1996–2001
Authors: Stabeno P. J. , Ladd C. , Reed R. K.
Published: May 2009

Cyclonic circulation dominates flow in the Bering Sea basin. The eastward flowing Aleutian North Slope Current (ANSC) flows along the north slope of the Aleutian Islands, turning northwestward in the southeast corner of the basin to form the Bering Slope Current (BSC). During the period 1997 to 2007, a pair of hydrographic lines was occupied 14 times in the southeastern portion of the basin. One transect was across the ANSC, and the second was across the BSC. In addition, a series of five yearlong moorings was deployed in a water depth of 1000 m in the ANSC, and a single yearlong mooring was deployed to the northeast in a water depth of 2200 m. At the primary mooring site, strong variability in temperature and salinity occurred at fortnightly and annual periods, while strong variability in the currents occurred at fortnightly and semiannual periods. The mean geostrophic flow relative to 1500 m, calculated from the 14 occupations of the hydrographic lines, was 3.1 × 106 m3 s−1 in the ANSC and 3.3 × 106 m3 s−1 in the BSC. A significant barotropic component, measured by the current meters, adds ∼3 × 106 m3 s−1 to the transport.
Responses of streamflow to climate and land surface change in the headwaters of the Yellow River Basin
Authors: Zheng Hongxing , Zhang Lu , Zhu Ruirui , Liu Changming , Sato Yoshinobu , Fukushima Yoshihiro
Published: May 2009

The headwater catchments of the Yellow River Basin are of great importance for the whole basin in terms of water resources, and streamflow from these catchments has decreased in the last decades. The concept of climate elasticity was used to assess the impacts of climate and land surface change on the streamflow. Results show that for the period 1960–2000 the elasticity of streamflow in relation to precipitation and potential evapotranspiration are 2.10 and −1.04, respectively, indicating that streamflow is more sensitive to precipitation than to potential evapotranspiration. However, land use change played a more important role than climate in reducing streamflow in the 1990s. It is estimated that land use change is responsible for more than 70% of the streamflow reduction in the 1990s, while climate change contributed to less than 30% of the reduction. The precipitation elasticity appears to have an inverse relationship with the runoff coefficient but a positive relationship with the aridity index, showing that the drier the catchment, the more sensitive the streamflow with respect to precipitation change.
High‐resolution numerical modeling of wave‐supported gravity‐driven mudflows
Authors: Hsu Tian‐Jian , Ozdemir Celalettin E. , Traykovski Peter A.
Published: May 2009

Wave‐supported gravity‐driven mudflow has been identified as a major offshore fine sediment transport mechanism of terrestrial sediment into the coastal ocean. This transport process essentially occurs within the wave boundary layer. In this study, wave‐supported gravity‐driven mudflow is investigated via a wave‐phase‐resolving high‐resolution numerical model for fluid mud transport. The model results are verified with field observation of sediment concentration and near‐bed flow velocities at Po prodelta. The characteristics of wave‐supported gravity‐driven mudflows are diagnosed by varying the bed erodibility, floc properties (fractal dimension), and rheological stresses in the numerical simulations. Model results for moderate concentration suggest that using an appropriately specified fractal dimension, the dynamics of wave‐supported gravity‐driven mudflow can be predicted without explicitly incorporating rheological stress. However, incorporating rheological stress makes the results less sensitive to prescribed fractal dimension. For high‐concentration conditions, it is necessary to incorporate rheological stress in order to match observed intensity of downslope gravity‐driven current. Model results are further analyzed to evaluate and calibrate simple parameterizations. Analysis suggests that when neglecting rheological stress, the drag coefficient decreases with increasing wave intensity and seems to follow a power law. However, when rheological stress is incorporated, the resulting drag coefficient is more or less constant (around 0.0013) for different wave intensities. Model results further suggest the bulk Richardson number has a magnitude smaller than 0.25 and is essentially determined by the amount of available soft mud (i.e., the erodibility), suggesting a supply limited condition for unconsolidated mud.
Positive trend in the mean speed and deformation rate of Arctic sea ice, 1979–2007
Authors: Rampal P. , Weiss J. , Marsan D.
Published: May 2009

Using buoy data from the International Arctic Buoy Program, we found that the sea ice mean speed has substantially increased over the last 29 years (+17% per decade for winter and +8.5% for summer). A strong seasonal dependence of the mean speed is also revealed, with a maximum in October and a minimum in April. The sea ice mean strain rate also increased significantly over the period (+51% per decade for winter and +52% for summer). We check that these increases in both sea ice mean speed and deformation rate are unlikely to be consequences of a stronger atmospheric forcing. Instead, they suggest that sea ice kinematics play a fundamental role in the albedo feedback loop and sea ice decline: increasing deformation means stronger fracturing, hence more lead opening, and therefore a decreasing albedo. This accelerates sea ice thinning in summer and delays refreezing in early winter, therefore decreasing the mechanical strength of the cover and allowing even more fracturing, larger drifting speed and deformation, and possibly a faster export of sea ice through the Fram Strait. The September minimum sea ice extent of 2007 might be a good illustration of this interplay between sea ice deformation and sea ice shrinking, as we found that for both winter 2007 and summer 2007 exceptionally large deformation rates affected the Arctic sea ice cover.
Quasi‐biennial oscillation influence on long‐period planetary waves in the Antarctic upper mesosphere
Authors: Hibbins R. E. , Jarvis M. J. , Ford E. A. K.
Published: May 2009

Long‐period planetary wave data derived from meteor wind observations recorded over a 12‐year period with the SuperDARN radar at Halley, Antarctica, are presented and compared with the phase of the quasi‐biennial oscillation (QBO) throughout the equatorial stratosphere. Enhanced planetary wave activity in the Antarctic upper mesosphere is found during the summer months, when the QBO in the equatorial upper stratosphere is westerly, and during the late winter, when the QBO in the upper stratosphere is easterly. These quasi‐biennial enhancements in planetary wave activity coincide with a reduction in strength, by up to 30%, of the late‐winter eastward winds in the Antarctic upper mesosphere. In addition, when the QBO is in the correct phase for enhanced planetary wave activity in the upper mesosphere above Halley, planetary wave activity measured in the upper mesosphere of the high‐latitude Northern Hemisphere is reduced (and vice versa). These results clearly indicate significant interhemispheric propagation of planetary waves from the winter to summer hemispheres. Observational evidence that the stratospheric QBO induces a strong enough QBO in the equatorial upper mesosphere to act as a gate to the interhemispheric propagation of these long‐period waves is discussed in light of these results.
Size distributions of fine silicate and other particles in Masaya's volcanic plume
Authors: Martin R. S. , Mather T. A. , Pyle D. M. , Power M. , Tsanev V. I. , Oppenheimer C. , Allen A. G. , Horwell C. J. , Ward E. P. W.
Published: May 2009

Direct‐sampling and remote‐sensing measurements were made at the crater rim of Masaya volcano (Nicaragua) to sample the aerosol plume emanating from the active vent. We report the first measurements of the size distribution of fine silicate particles (d < 10 μm) in Masaya's plume, by automated scanning electron microscopy (QEMSCAN) analysis of a particle filter. The particle size distribution was approximately lognormal with modal d ∼ 1.15 μm. The majority of these particles were found to be spherical. These particles are interpreted to be droplets of quenched magma produced by a spattering process. Compositional analyses confirm earlier reports that the fine silicate particles show a range of compositions between that of the degassing magma and nearly pure silica and that the extent of compositional variability decreases with increasing particle size. These results indicate that fine silicate particles are altered owing to reactions with acidic droplets in the plume. The emission flux of fine silicate particles was estimated as ∼1011 s−1, equivalent to ∼55 kg d−1. Sun photometry, aerosol spectrometry, and thermal precipitation were used to determine the overall particle size distribution of the plume (0.01 < d(μm) < 10). Sun photometry and aerosol spectrometry measurements indicate the presence of a large number of particles (assumed to be aqueous) with d ∼ 1 μm. Aerosol spectrometry measurements further show an increase in particle size as the nighttime approached. The emission flux of particles from Masaya was estimated as ∼1017 s−1, equivalent to ∼5.5 Mg d−1 where d < 4 μm.