bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel 1,2‐Dicarba‐closo‐dodecaborane(12) Derivatives of Selenium
Authors: Wrackmeyer Bernd , García Hernández Zureima , Kempe Rhett , Herberhold Max
Published: October 2006

Lithiation of 1,2‐dicarba‐closo‐dodecaborane(12) (1) followed by insertion of selenium into both C–Li bonds leads to the 1,2‐diselenolato‐1,2‐dicarba‐closo‐dodecaborane(12) dianion (3), which is converted by oxidative coupling into the cyclic eight‐membered bis(diselane) 4 with annellated carborane moieties. Oxidative addition of 4 to ethenebis(triphenylphosphane)platinum(0) gives the bis(triphenylphosphane)platinum(II) complex 7, which contains a chelating 1,2‐diselenolato‐1,2‐dicarba‐closo‐dodecaborane(12) ligand, by symmetric cleavage of the eight‐membered ring in 4 and displacement of ethene. The molecular structures of 4 and 7 were determined by X‐ray analysis. The solution‐state structures of the new compounds are supported by multinuclear NMR data (1H, 11B, 13C, 29Si, 31P, 77Se, 195Pt). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A Comparative Study of Chalcogenated Phosphanylborohydrides[EPR2BH3]– (R = Ph, tBu) and Triorganophosphane Chalcogenides EPPh2CH3 (E = O, S, Se, Te)
Authors: Dornhaus Franz , Bolte Michael , Lerner Hans‐Wolfram , Wagner Matthias
Published: October 2006

Chalcogenation of the phosphanylborohydrides K(PPh2BH3) and K(PtBu2BH3) with N2O, S8, Se∞, and Te∞ leads to the corresponding species K(EPR2BH3) in excellent yield (E = O–Te; R = Ph, tBu). The parent systems as well as all the chalcogen derivatives have been structurally characterised as their 18‐crown‐6 adducts by X‐ray crystallography. In the case of [K(18‐c‐6)][EPPh2BH3] the anionic ligand binds to the K+ ion through both its E atom and its BH3 substituent. Significantly larger K–B distances together with shorter K–E contacts are observed in the sterically more congested tert‐butyl derivatives [K(18‐c‐6)][EPtBu2BH3]. Based on a comparison of characteristic NMR parameters (e.g. 1JP,B, 1JP,C) of K(EPPh2BH3) and EPPh2CH3, we come to the conclusion that the formal replacement of CH3+ by BH3 leads to a significant increase in the p character of the E–P bond, which therefore indicates that [PPh2BH3]– is better suited to direct electron density towards an acceptor atom than its triorganophosphane congener PPh2CH3. In line with this interpretation, displacement experiments between K(PPh2BH3) and EPPh2CH3 (E = S–Te) resulted in the quantitative formation of K(EPPh2BH3) and PPh2CH3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A poly(lactide‐co‐glycolide)/hydroxyapatite composite scaffold with enhanced osteoconductivity
Authors: Kim Sang‐Soo , Ahn Kang‐Min , Park Min Sun , Lee Jong‐Ho , Choi Cha Yong , Kim Byung‐Soo
Published: October 2006

Biodegradable polymer/ceramic scaffolds can overcome the limitations of conventional ceramic bone substitutes. However, the conventional methods of polymer/ceramic scaffold fabrication often use organic solvents, which might be harmful to cells or tissues. Moreover, scaffolds fabricated with the conventional methods have limited ceramic exposure on the scaffold surface since the polymer solution envelopes the ceramic particles during the fabrication process. In this study, we developed a novel fabrication method for the efficient exposure of ceramic onto the scaffold surface, which would enhance the osteoconductivity and wettability of the scaffold. Poly(D,L‐lactide‐co‐glycolide)/nanohydroxyapatite (PLGA/HA) scaffolds were fabricated by the gas foaming and particulate leaching (GF/PL) method without the use of organic solvents. Selective staining of ceramic particles indicated that HA nanoparticles exposed to the scaffold surface were observed more abundantly in the GF/PL scaffold than in the conventional solvent casting and particulate leaching (SC/PL) scaffold. Both types of scaffolds were implanted to critical size defects in rat skulls for 8 weeks. The GF/PL scaffolds exhibited significantly enhanced bone regeneration when compared with the SC/PL scaffolds. Histological analyses and microcomputed tomography of the regenerated tissues showed that bone formation was more extensive on the GF/PL scaffolds than on the SC/PL scaffolds. Compared with the SC/PL scaffolds, the enhanced bone formation on the GF/PL scaffolds may result from the higher exposure of HA nanoparticles to the scaffold surface. These results show that the biodegradable polymer/ceramic composite scaffolds fabricated with the novel GF/PL method can enhance bone regeneration compared with those fabricated with the conventional SC/PL method. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
The application of Fe3O4 nanoparticles in cancer research: A new strategy to inhibit drug resistance
Authors: Wang Xuemei , Zhang Renyun , Wu Chunhui , Dai Yongyuan , Song Min , Gutmann Sebastian , Gao Feng , Lv Gang , Li Jingyuan , Li Xiaomao , Guan Zhiqun , Fu Degang , Chen Baoan
Published: October 2006

Although much effort has been extended to the efficient cancer therapies, the drug resistance is still a major obstacle in cancer chemotherapeutic treatments. Almost 90% of the cancer therapy failure is caused by the relative problems. Recently, the application of drug coated polymer nanospheres and nanoparticles to inhibit the related drug resistance has attracted much attention. In this report, we have explored a novel strategy to inhibit the multidrug resistance of the targeted tumor cells by combining the unique properties of tetraheptylammonium capped Fe3O4 magnetic nanoparticles with the drug accumulation of anticancer drug daunorubicin. Our results of confocal fluorescence and atomic force microscopy (AFM) as well as electrochemical studies demonstrate the remarkable synergistic effect of Fe3O4 nanoparticles on drug uptake of daunorubicin in leukemia K562 cells. These observations indicate that the interaction between the magnetic nanoparticles Fe3O4 and biologically active molecules on the membrane of leukemia cell lines may contribute to their beneficial effect on cellular uptake so that the synergistic enhanced effect of magnetic nanoparticles Fe3O4 on drug uptake of drug resistance leukemia K562 cells could be observed upon application of the Fe3O4 nanoparticles. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Stability of passivated 316L stainless steel oxide films for cardiovascular stents
Authors: Shih Chun‐Che , Shih Chun‐Ming , Chou Kuang‐Yi , Lin Shing‐Jong , Su Yea‐Yang
Published: October 2006

Passivated 316L stainless steel is used extensively in cardiovascular stents. The degree of chloride ion attack might increase as the oxide film on the implant degrades from exposure to physiological fluid. Stability of 316L stainless steel stent is a function of the concentration of hydrated and hydrolyated oxide concentration inside the passivated film. A high concentration of hydrated and hydrolyated oxide inside the passivated oxide film is required to maintain the integrity of the passivated oxide film, reduce the chance of chloride ion attack, and prevent any possible leaching of positively charged ions into the surrounding tissue that accelerate the inflammatory process. Leaching of metallic ions from corroded implant surface into surrounding tissue was confirmed by the X‐ray mapping technique. The degree of thrombi weight percentage [Wao: (2.1 ± 0.9)%; Wep: (12.5 ± 4.9)%, p < 0.01] between the amorphous oxide (AO) and the electropolishing (EP) treatment groups was statistically significant in ex‐vivo extracorporeal thrombosis experiment of mongrel dog. The thickness of neointima (Tao: 100 ± 20 μm; Tep: 500 ± 150 μm, p < 0.01) and the area ratio of intimal response at 4 weeks (ARao: 0.62 ± 0.22; ARep: 1.15 ± 0.42, p < 0.001) on the implanted iliac stents of New Zealand rabbit could be a function of the oxide properties. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Perfect coloring and linearly χ‐bound P6‐free graphs
Authors: Choudum S. A. , Karthick T. , Shalu M. A.
Published: October 2006

We derive decomposition theorems for P6, K1 + P4‐free graphs, P5, K1 + P4‐free graphs and P5, K1 + C4‐free graphs, and deduce linear χ‐binding functions for these classes of graphs (here, Pn (Cn) denotes the path (cycle) on n vertices and K1 + G denotes the graph obtained from G by adding a new vertex and joining it with every vertex of G). Using the same techniques, we also obtain an optimal χ‐binding function for P5, C4‐free graphs which is an improvement over that given in [J. L. Fouquet, V. Giakoumakis, F. Maire, and H. Thuillier, 1995, Discrete Math, 146, 33–44.]. © 2006 Wiley Periodicals, Inc. J Graph Theory 54: 293–306, 2007
Differentiation of human mesenchymal stem cells and articular chondrocytes: Analysis of chondrogenic potential and expression pattern of differentiation‐related transcription factors
Authors: Karlsson Camilla , Brantsing Camilla , Svensson Teresia , Brisby Helena , Asp Julia , Tallheden Tommi , Lindahl Anders
Published: October 2006

Mesenchymal stem cells (MSCs) are a candidate for replacing chondrocytes in cell‐based repair of cartilage lesions. However, it has not been clarified if these cells can acquire the hyaline phenotype, and whether chondrocytes and MSCs show the same expression patterns of critical control genes in development. In order to study this, articular chondrocytes and iliac crest derived MSCs were allowed to differentiate in pellet mass cultures. Gene expression of markers for the cartilage phenotype, helix‐loop‐helix (HLH) transcription factors, and chondrogenic transcription factors were analyzed by real‐time PCR. Matrix production was assayed using biochemical analysis for hydroxyproline, glycosaminoglycans, and immunohistochemistry for collagen types I and II. Significantly decreased expression of collagen type I was accompanied by increased expression of collagen types IIA and IIB during differentiation of chondrocytes, indicating differentiation towards a hyaline phenotype. Chondrogenesis in MSCs on the other hand resulted in up‐regulation of collagen types I, IIA, IIB, and X, demonstrating differentiation towards cartilage of a mixed phenotype. Expression of HES1 increased significantly during chondrogenesis in chondrocytes while expression in MSCs was maintained at a low level. The HLH gene HES5 on the other hand was only detected in chondrocytes. Expression of ID1 decreased significantly in chondrocytes while the opposite was seen in MSCs. These findings suggest that chondrocytes and MSCs differentiated and formed different subtypes of cartilage, the hyaline and a mixed cartilage phenotype, respectively. Differentially regulated HLH genes indicated the possibility for HLH proteins in regulating chondrogenic differentiation. This information is important to understand the potential use of MSCs in cartilage repair. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:152–163, 2007
Klippel‐Feil syndrome in an Early Hungarian Period juvenile skeleton from Austria
Authors: Pany D. , Teschler‐Nicola M.
Published: October 2006

The excellently preserved skeleton of a juvenile from the Early Hungarian Period (10th century AD), recently excavated in Gnadendorf (Lower Austria), displays typical symptoms of Type II congenital ‘Klippel‐Feil syndrome’ (KFS): fused cervical vertebrae 2 and 3, and fused thoracic vertebrae 2 and 3. Other features observed in this skeleton clinically reported for KFS include a basilar impression and a spina bifida occulta. The bilateral symmetrical hypoplasia of the basilar part of the occipital bone is probably also linked to this syndrome, as well as the constricted external acoustic meati, which almost certainly led to hearing impairment. A cranial lesion and its possible consequences are discussed in the context of the specific KFS alterations. Copyright © 2006 John Wiley & Sons, Ltd.
Genomic aberrations are rare in urothelial neoplasms of patients 19 years or younger
Authors: Wild PJ , Giedl J , Stoehr R , Junker K , Boehm S , van Oers JMM , Zwarthoff EC , Blaszyk H , Fine SW , Humphrey PA , Dehner LP , Amin MB , Epstein JI , Hartmann A
Published: October 2006

Urothelial neoplasms in patients 19 years of age or younger are rare, and the data regarding clinical outcome are conflicting. Molecular data are not available. Urothelial tumours from 14 patients aged 4 to 19 years were analysed, including FGFR3 and TP53 mutation screening, comparative genomic hybridization (CGH), UroVysion FISH analysis, polymerase chain reaction for human papillomavirus (HPV), microsatellite analysis using the NIH consensus panel for detection of microsatellite instability (MSI) and six markers for loss of heterozygosity on chromosome arms 9p, 9q, and 17p and immunohistochemistry for TP53, Ki‐67, CK20 and the mismatch repair proteins (MRPs) hMSH2, hMLH1, and hMSH6. Based on the 2004 WHO classification, one urothelial papilloma, seven papillary urothelial neoplasms of low malignant potential (PUNLMPs), five low‐grade, and one high‐grade papillary urothelial carcinoma were included. No multifocal tumours were found and recurrence was seen in only one patient with a urothelial papilloma. All patients were alive with no evidence of disease at a median follow‐up of 3.0 years. We found no mutations in FGFR3, deletions of chromosome arms 9p, 9q or 17p, MSI or MRP loss, or HPV positivity in any of the patients. Three cases showed chromosome alterations in CGH analyses, urothelial dedifferentiation with CK20 overexpression, or aneuploidy, and one TP53 mutation with TP53 overexpression was found. Urothelial neoplasms in people younger than 20 years are predominantly low grade and are associated with a favourable clinical outcome. Genetic alterations frequently seen in older adults are extremely rare in young patients. Urothelial neoplasms in children and young adults appear to be biologically distinct and lack genetic instability in most cases. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Conjunctival melanoma in a six‐year‐old female
Authors: Polat Aziz , Yıldırım Cem , Işık Balcı Yasemin , İnce Tülay , Bir Ferda , Demirkan Neşe , Bican Mevlüt
Published: October 2006

Conjunctival melanoma (CM) is a highly malignant tumor that derives from melanocytes and is rarely seen in children. This report describes a 6‐year‐old female diagnosed with CM. Pediatr Blood Cancer 2008;50:384–386. © 2006 Wiley‐Liss, Inc.
Protective effects of Ginkgo biloba extract against mercury(II)‐induced cardiovascular oxidative damage in rats
Authors: Tunali‐Akbay Tugba , Sener Goksel , Salvarli Hanife , Sehirli Ozer , Yarat Aysen
Published: October 2006

This study was designed to determine the possible protective effect of Ginkgo biloba extract (EGb) against Hg II‐induced oxidative damage and also thromboplastic activity in the aorta and heart tissues. Wistar albino rats of either sex (200–250 g) were divided into four groups. Rats were injected intraperitoneally with (1) control (C) group: 0.9% NaCl; (2) EGb group: Ginkgo biloba extract (Abdi Ibrahim Pharmaceutical Company, Istanbul, Turkey) at a dose of 50 mg/kg/day; (3) Hg group: a single dose of 5 mg/kg mercuric chloride (HgCl2); and (4) Hg + EGb group: First day EGb at a dose of 50 mg/kg/day, i.p., 1 hour after HgCl2 (5 mg/kg) injection; following four days EGb at a dose 50 mg/kg/day, i.p. After decapitation of the rats, trunk blood was obtained and serum tumor necrosis factor‐α (TNF‐α), lactate dehydrogenase (LDH) activity, and malondialdehyde (MDA) and glutathione (GSH) levels were analysed. In the aorta and heart tissues total protein, MDA, GSH levels and thromboplastic activity were determined. The results revealed that HgCl2 induced oxidative tissue damage, as evidenced by increases in MDA levels and decreased GSH levels both in serum and tissue samples. Thromboplastic activity was increased significantly following Hg administration, which verifies the cardiotoxic effects of HgCl2. Serum LDH and TNF‐α were elevated in the Hg group compared with the control group. Since EGb treatment reversed these responses, it seems likely that Ginkgo biloba extract can protect the cardiovascular tissues against HgCl2‐induced oxidative damage. Copyright © 2006 John Wiley & Sons, Ltd.
Innovative packaging for minimally processed fruits
Authors: Avella M. , Bruno G. , Errico M. E. , Gentile G. , Piciocchi N. , Sorrentino A. , Volpe M. G.
Published: October 2006

Novel nanocomposite films for use in the packaging of foods ready for consumption and based on isotactic polypropylene (iPP) filled with innovative calcium carbonate nanoparticles, as well as having spherical and elongated shape and covered with appropriate coating agent able to better interact with the iPP matrix, were prepared and characterized. Morphological, thermal, mechanical and transport characterizations on nanocomposite films were performed. The results evidenced a good dispersion of the nanofiller into the polymeric matrix as well as an increase in mechanical parameters such as modulus. Moreover, a drastic reduction of iPP permeability to both oxygen and carbon dioxide was also recorded. Migration tests evidenced that these nanocomposites are suitable for food packaging applications. Finally, the analysis of some shelf‐life parameters carried out on packaged minimally processed apples showed that these materials are able to preserve for up to 10 days apple slices, limiting oxidation processes and microbiological growth. Copyright © 2006 John Wiley & Sons, Ltd.
Regression analysis of failure time data with informative interval censoring
Authors: Zhang Zhigang , Sun Liuquan , Sun Jianguo , Finkelstein Dianne M.
Published: October 2006

Interval censoring arises when a subject misses prescheduled visits at which the failure is to be assessed. Most existing approaches for analysing interval‐censored failure time data assume that the censoring mechanism is independent of the true failure time. However, there are situations where this assumption may not hold. In this paper, we consider such a situation in which the dependence structure between the censoring variables and the failure time can be modelled through some latent variables and a method for regression analysis of failure time data is proposed. The method makes use of the proportional hazards frailty model and an EM algorithm is presented for estimation. Finite sample properties of the proposed estimators of regression parameters are examined through simulation studies and we illustrate the method with data from an AIDS study. Copyright © 2006 John Wiley & Sons, Ltd.
Accounting for expected attrition in the planning of community intervention trials
Authors: Taljaard Monica , Donner Allan , Klar Neil
Published: October 2006

Trials in which intact communities are the units of randomization are increasingly being used to evaluate interventions which are more naturally administered at the community level, or when there is a substantial risk of treatment contamination. In this article we focus on the planning of community intervention trials in which k communities (for example, medical practices, worksites, or villages) are to be randomly allocated to each of an intervention and a control group, and fixed cohorts of m individuals enrolled in each community prior to randomization. Formulas to determine k or m may be obtained by adjusting standard sample size formulas to account for the intracluster correlation coefficient ρ. In the presence of individual‐level attrition however, observed cohort sizes are likely to vary. We show that conventional approaches of accounting for potential attrition, such as dividing standard sample size formulas by the anticipated follow‐up rate π or using the average anticipated cohort size mπ, may, respectively, overestimate or underestimate the required sample size when cluster follow‐up rates are highly variable, and m or ρ are large. We present new sample size estimation formulas for the comparison of two means or two proportions, which appropriately account for variation among cluster follow‐up rates. These formulas are derived by specifying a model for the binary missingness indicators under the population‐averaged approach, assuming an exchangeable intracluster correlation coefficient, denoted by τ. To aid in the planning of future trials, we recommend that estimates for τ be reported in published community intervention trials. Copyright © 2006 John Wiley & Sons, Ltd.
Multidisciplinary investigation of eco‐industrial parks
Authors: Haskins Cecilia
Published: October 2006

Since the revelation of an industrial symbiosis in Denmark, researchers have attempted to draw out the patterns of success and replicate the Kalundborg model in brown‐ and greenfield eco‐industrial parks. Establishment of these parks is seen to offer hope to both industrialized and developing nations for achieving sustainable development objectives. This paper reviews the relevant literature and considers the relative usefulness of industrial ecology, systems science, and industrial network theory for understanding eco‐industrial parks. This multidisciplinary approach considers knowledge‐sharing techniques such as pattern languages as a mechanism for sharing best results. The paper closes with suggestions for the direction of further research. © 2006 Wiley Periodicals, Inc. Syst Eng 9:313–330, 2006
Introduction: American Jewish Writing Today
Authors: Sokoloff Naomi
Published: October 2006

This is an exciting time for North American Jewish literature. In the past ten years, there has been an explosion of writing by new and established authors. In the field of fiction alone, the shelves have filled with titles by such fine talent as Pearl Abraham, Melvin Jules Bukiet, Michael Chabon, Nathan Englander, Myla Goldberg, Ehud Havatzelet, Dara Horn, Jonathan Safran Foer, Joan Leegant, Tova Mirvis, Jon Papernick, Jonathan Rosen, Aryeh Lev Stollman, and many others, as well as new works by veteran writers such as Allegra Goodman, Thane Rosenbaum, and Steve Stern. Add to these names the preeminent Cynthia Ozick, and don’t forget Philip Roth, whose productivity continues unabated and whose latest novels include some of his strongest work ever. A variety of striking themes has come to the fore in this new wave of literary creativity. Notable trends include an unprecedented attention to religion (especially Orthodox Jewish life); a fascination with women’s lives and with questions of gender and sexual orientation; a concern with the experiences of the second and succeeding generations of the Holocaust; a nostalgia for and rediscovery of the old country; a consideration of new Americans in the 1980s and 1990s; and a rethinking of what it means to be a Jew in Israel and in the Diaspora.
So Easily Assimilated: The New Immigrant Chic
Authors: Rovner Adam
Published: October 2006

Last year, a friend drew my attention to the lyrics of a famous song in Leonard Bernstein’s Candide, the composer’s first attempt in 1956 to write the “Great American Opera.” The song, “I Am Easily Assimilated,” remains one of the best-loved musical numbers from the play and includes the following lines:
My father came from Rovno Gubernya.But now I’m here, I’m dancing a tango….My father spoke a High Middle Polish.In one half-hour I’m talking in Spanish:Por favor! Toreador!I am easily assimilated.I am so easily assimilated.
The irreverent lyrics are often credited to Bernstein himself and refer to the biography of his father, Sam, who immigrated to America from the province (gubernya) of Rovno. This Jewish tango exhibits a musical pastiche of Hispanic and Klezmer traditions in its instrumentation and displays a manic shift from Russian to English to Spanish that mirrors the composer’s playful notation that it be played “Moderato Hassidicamente.” The song is both a parody of and a monument to the assimilatory spirit. My friend, however, thought I would be interested in the song because my last name is Rovner; he expected that I would want to track down Bernstein’s reference to the area, Rovno, that lent my family its patronymic.
Modeling Culture Profiles of the Heterocystous N2‐Fixing Cyanobacterium Anabaenaflos‐aquae
Authors: Pinzon Neissa M. , Ju Lu‐Kwang
Published: October 2006

Heterocyst differentiation is a unique feature of nitrogen‐fixing cyanobacteria, potentially important for photobiological hydrogen production. Despite the significant advances in genetic investigation on heterocyst differentiation, there were no quantitative culture‐level models that describe the effects of cellular activities and cultivation conditions on the heterocyst differentiation. Such a model was developed in this study, incorporating photosynthetic growth of vegetative cells, heterocyst differentiation, self‐shading effect on light penetration, and nitrogen fixation. The model parameters were determined by fitting experimental results from the growth of the heterocystous cyanobacterium Anabaena flos‐aquae CCAP 1403/13f in media without and with different nitrate concentrations and under continuous illumination of white light at different light intensities (2, 5, 10, 17, 20 and 50 μE m−2 s−1). The model describes the experimental profiles well and gives reasonable predictions even for the transition of growth from that on external N source to that via nitrogen fixation, responding to the change in external N concentrations. The significance and implications of the best‐fit values of the model parameters are discussed.
Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation
Authors: Dentener F. , Drevet J. , Lamarque J. F. , Bey I. , Eickhout B. , Fiore A. M. , Hauglustaine D. , Horowitz L. W. , Krol M. , Kulshrestha U. C. , Lawrence M. , Galy‐Lacaux C. , Rast S. , Shindell D. , Stevenson D. , Van Noije T. , Atherton C. , Bell N. , Bergman D. , Butler T. , Cofala J. , Collins B. , Doherty R. , Ellingsen K. , Galloway J. , Gauss M. , Montanaro V. , Müller J. F. , Pitari G. , Rodriguez J. , Sanderson M. , Solmon F. , Strahan S. , Schultz M. , Sudo K. , Szopa S. , Wild O.
Published: October 2006

We use 23 atmospheric chemistry transport models to calculate current and future (2030) deposition of reactive nitrogen (NOy, NHx) and sulfate (SOx) to land and ocean surfaces. The models are driven by three emission scenarios: (1) current air quality legislation (CLE); (2) an optimistic case of the maximum emissions reductions currently technologically feasible (MFR); and (3) the contrasting pessimistic IPCC SRES A2 scenario. An extensive evaluation of the present‐day deposition using nearly all information on wet deposition available worldwide shows a good agreement with observations in Europe and North America, where 60–70% of the model‐calculated wet deposition rates agree to within ±50% with quality‐controlled measurements. Models systematically overestimate NHx deposition in South Asia, and underestimate NOy deposition in East Asia. We show that there are substantial differences among models for the removal mechanisms of NOy, NHx, and SOx, leading to ±1 σ variance in total deposition fluxes of about 30% in the anthropogenic emissions regions, and up to a factor of 2 outside. In all cases the mean model constructed from the ensemble calculations is among the best when comparing to measurements. Currently, 36–51% of all NOy, NHx, and SOx is deposited over the ocean, and 50–80% of the fraction of deposition on land falls on natural (nonagricultural) vegetation. Currently, 11% of the world's natural vegetation receives nitrogen deposition in excess of the “critical load” threshold of 1000 mg(N) m−2 yr−1. The regions most affected are the United States (20% of vegetation), western Europe (30%), eastern Europe (80%), South Asia (60%), East Asia (40%), southeast Asia (30%), and Japan (50%). Future deposition fluxes are mainly driven by changes in emissions, and less importantly by changes in atmospheric chemistry and climate. The global fraction of vegetation exposed to nitrogen loads in excess of 1000 mg(N) m−2 yr−1 increases globally to 17% for CLE and 25% for A2. In MFR, the reductions in NOy are offset by further increases for NHx deposition. The regions most affected by exceedingly high nitrogen loads for CLE and A2 are Europe and Asia, but also parts of Africa.
Analysis of the correlations between atmospheric boundary‐layer and free‐tropospheric temperatures in the tropics
Authors: Wu Wei , Dessler Andrew E. , North Gerald R.
Published: October 2006

We investigate the vertical correlations between temperature variations at 925 hPa, in the atmospheric boundary layer, and temperature variations in the free troposphere and lower stratosphere in the Tropics in daily and monthly averaged satellite and radiosonde measurements and in six General Circulation Models (GCMs). The results show generally positive correlations between the boundary layer temperatures and temperatures in the rest of the troposphere, with negative correlations occurring around the tropopause and in the lower stratosphere. In typically non‐convective regions, the variations at the surface show little connection to mid and upper tropospheric temperature variations. In the convective Western Pacific, the correlations are low in the mid troposphere and much larger around 200 hPa. GCMs generally capture the temperature correlations, although as a group they tend to overpredict the coupling between the boundary layer and the rest of the troposphere. The basic correlation patterns of monthly temperature are found similar to the daily results.
Measurements of emission factors for primary carbonaceous particles from residential raw‐coal combustion in China
Authors: Chen Yingjun , Zhi Guorui , Feng Yanli , Fu Jiamo , Feng Jialiang , Sheng Guoying , Simoneit Bernd R. T.
Published: October 2006

The emission factors (EFs) of particles and their carbonaceous fractions, including black carbon (BC) and organic carbon (OC), are measured for residential burning of coal‐chunks. Nine types of coals with wide‐ranged thermal maturities were used. Particulate emissions from coal‐stove are collected on quartz fiber filters through a dilution sampling system and analyzed for BC and OC by thermal‐optical method. The EFs of particulate matter, OC, and BC from bituminous coal burning are 16.77, 8.29, and 3.32 g/kg, respectively, on the basis of burned dry and ash‐free (daf) coal mass. They were much higher than those of anthracites, which are 0.78, 0.04, and 0.004 g/kg, respectively. Annual emission inventories of particles, OC, and BC from household coal burning are also estimated based on the EFs and coal consumption. The results of the calculations are 917.8, 477.7, and 128.4 gigagrams (Gg) for total particles, OC, and BC emitted in China during the year 2000.
Shear‐induced bubble coalescence in rhyolitic melts with low vesicularity
Authors: Okumura Satoshi , Nakamura Michihiko , Tsuchiyama Akira
Published: October 2006

We have experimentally demonstrated for the first time, shear‐induced development of bubble size and shape in a rhyolitic melt. The deformation experiments have been performed by using an externally heated, piston‐cylinder type apparatus with a rotational piston. At 975°C, the vesiculated rhyolitic melts having cylindrical shape were twisted at rotational speeds of 0.3, 0.5 and 1.0 rpm. The number, size and shape of bubbles were then measured by using the X‐ray computed tomography. The experimental results show that coalescence of bubbles occur even at low vesicularity (20 vol.%) and the degree of coalescence is enhanced with the shear rate. Because the shear‐induced deformation seems to be produced for magmas ascending in a volcanic conduit, we propose the possibility of the vesiculated magma undergoing bubble coalescence at a significant depth (low vesicularity), resulting in the formation of permeable magmas, at least near the conduit wall.
On the use of computerized tomography scan analysis to determine the genesis of very high resolution seismic reflection facies
Authors: Duchesne Mathieu J. , Long Bernard F. , Labrie Jacques , Simpkin Peter G.
Published: October 2006

Computerized tomography scanner (CT scanner) is a powerful tool that can reveal millimeter‐scale stratigraphy from cores. The coupling of very high resolution (VHR) seismic data with CT scan data represents a new approach to determine with more confidence the genesis of seismic facies. However, prior to the application of such a method, a clear understanding of the relationship between these two types of data (e.g., physical parameters in common) is necessary. The application of CT scan analysis along with VHR seismic data showed that seismic and CT scan signals respond to different physical properties of the sediments. Results suggest that similar seismic facies may correspond to different CT scan facies and, conversely, that different CT scan facies may have the same acoustic response. Sedimentary structures observed on the CT scan imagery suggest that a seismic response should be linked to a synthesis of lithological variations instead of a single and unique lithology change/contrast. Furthermore, this study points toward the fact that the geometry of the reflections does not always correspond to the geometry of sedimentary structures but rather to the anisotropy of the physical properties of the deposit. Consequently, to give a genetic connotation to the internal reflection pattern of a seismic facies can be misleading in some cases. Finally, the fine‐scale sedimentological analysis based on very high resolution CT scan data is useful to determine very fine seismic analogs and thus to better explain the seismic expression of a deposit.
Human GSTA1-1 reduces c-Jun N-terminal kinase signalling and apoptosis in Caco-2 cells
Authors: Romero Laura , Andrews Kimberly , Ng Lorraine , O'Rourke Kelly , Maslen Ann , Kirby Gordon
Published: October 2006

The effect of GSTA1-1 (glutathione S-transferase Alpha 1-1) on JNK (c-Jun N-terminal kinase) activation was investigated in Caco-2 cells in which GSTA1 expression increases with degree of confluency, and in MEF3T3 cells with Tet-Off-inducible GSTA1 expression. Comparison of GSTA1 expression in pre-confluent, confluent and 8-day post-confluent Caco-2 cells revealed progressively increasing mRNA and protein levels at later stages of confluency. Exposure of pre-confluent cells to stress conditions including IL-1β (interleukin-1β), H2O2 or UV irradiation resulted in marked increases in JNK activity as indicated by c-Jun phosphorylation. However, JNK activation was significantly reduced in post-confluent cells exposed to the same stresses. Western-blot analysis of GSTA1-1 protein bound to JNK protein pulled down from cellular extracts showed approx. 4-fold higher GSTA1-1–JNK complex formation in post-confluent cells compared with pre-confluent cells. However, stress conditions did not alter the amount of GSTA1-1 bound to JNK. The role of GSTA1-1 in JNK suppression was more specifically revealed in Tet-Off-inducible MEF3T3-GSTA1-1 cells in which GSTA1 overexpression significantly reduced phosphorylation of c-Jun following exposure to IL-1β, H2O2 and UV irradiation. Finally, the incidence of tumour necrosis factor α/butyrate-induced apoptosis was significantly higher in pre-confluent Caco-2 cells expressing low levels of GSTA1 compared with post-confluent cells. These results indicate that GSTA1 suppresses activation of JNK signalling by a pro-inflammatory cytokine and oxidative stress and suggests a protective role for GSTA1-1 in JNK-associated apoptosis.
Phosphorylation status of the Kep1 protein alters its affinity for its protein binding partner alternative splicing factor ASF/SF2
Authors: Robard Cécile , Daviau Alex , Di Fruscio Marco
Published: October 2006

Mutations in the Drosophila kep1 gene, encoding a single maxi KH (K homology) domain-containing RNA-binding protein, result in a reduction of fertility in part due to the disruption of the apoptotic programme during oogenesis. This disruption is concomitant with the appearance of an alternatively spliced mRNA isoform encoding the inactive caspase dredd. We generated a Kep1 antibody and have found that the Kep1 protein is present in the nuclei of both the follicle and nurse cells during all stages of Drosophila oogenesis. We have shown that the Kep1 protein is phosphorylated in ovaries induced to undergo apoptosis following treatment with the topoisomerase I inhibitor camptothecin. We have also found that the Kep1 protein interacts specifically with the SR (serine/arginine-rich) protein family member ASF/SF2 (alternative splicing factor/splicing factor 2). This interaction is independent of the ability of Kep1 to bind RNA, but is dependent on the phosphorylation of the Kep1 protein, with the interaction between Kep1 and ASF/SF2 increasing in the presence of activated Src. Using a CD44v5 alternative splicing reporter construct, we observed 99% inclusion of the alternatively spliced exon 5 following kep1 transfection in a cell line that constitutively expresses activated Src. This modulation in splicing was not observed in the parental NIH 3T3 cell line in which we obtained 7.5% exon 5 inclusion following kep1 transfection. Our data suggest a mechanism of action in which the in vivo phosphorylation status of the Kep1 protein affects its affinity towards its protein binding partners and in turn may allow for the modulation of alternative splice site selection in Kep1–ASF/SF2-dependent target genes.
Polymerization of human angiotensinogen: insights into its structural mechanism and functional significance
Authors: Stanley Peter , Serpell Louise C. , Stein Penelope E.
Published: October 2006

In the present study, we have investigated the in vitro polymerization of human plasma AGT (angiotensinogen), a non-inhibitory member of the serpin (SERine Protease INhibitor) family. Polymerization of AGT is thought to contribute to a high molecular mass form of the protein in plasma that is increased in pregnancy and pregnancy-associated hypertension. The results of the present study demonstrate that the polymerization of AGT occurs through a novel mechanism which is primarily dependent on non-covalent linkages, while additional disulfide linkages formed after prolonged incubation are not essential for either formation or stability of polymers. We present the first analyses of AGT polymers by electron microscopy, CD spectroscopy, stability assays and sensitivity to proteinases and we conclude that their structure differs from the ‘loop-sheet’ polymers typical of inhibitory serpins. Histidine residues within the unique N-terminal extension of AGT appear to influence polymer formation, although polymer formation can still take place after their removal by renin. At a functional level, we show that AGT polymers are not substrates for renin, so polymerization of AGT in plasma would predictably lead to decreased formation of AngI (angiotensin I) with blood pressure lowering. Polymerization may therefore be an appropriate response to hypertension. The ability of AGT to protect its renin cleavage site through polymerization may explain why the AngI decapeptide has remained linked to the large and apparently inactive serpin body throughout evolution.
Insulin activates human sterol-regulatory-element-binding protein-1c (SREBP-1c) promoter through SRE motifs
Authors: Dif Nicolas , Euthine Vanessa , Gonnet Estelle , Laville Martine , Vidal Hubert , Lefai Etienne
Published: October 2006

In the present study, we aimed to decipher the mechanisms involved in the transcriptional effect of insulin on the SREBP-1c specific promoter of the human srebf-1 gene. Using luciferase reporter gene constructs in HEK-293 cells (human embryonic kidney cells), we demonstrated that the full effect of insulin requires the presence of SREs (sterol response elements) in the proximal region of the promoter. Furthermore, insulin increases the binding of SREBP-1 (sterol-regulatory-element-binding protein-1) to this promoter region in chromatin immunoprecipitation assay. We also found that the nuclear receptors LXRs (liver X receptors) strongly activate SREBP-1c gene expression and identified the LXRE (LXR-response element) involved in this effect. However, our results suggested that these LXREs do not play a major role in the response to insulin. Finally, using expression vectors and adenoviruses allowing ectopic overexpressions of the human mature forms of SREBP-1a or SREBP-1c, we demonstrated the direct role of SREBP-1 in the control of SREBP-1c gene expression in human skeletal-muscle cells. Altogether, these results strongly suggest that the SREBP-1 transcription factors are the main mediators of insulin action on SREBP-1c expression in human tissues.
A novel suite of cyclotides from Viola odorata: sequence variation and the implications for structure, function and stability
Authors: Ireland David C. , Colgrave Michelle L. , Craik David J.
Published: October 2006

Cyclotides are a fascinating family of plant-derived peptides characterized by their head-to-tail cyclized backbone and knotted arrangement of three disulfide bonds. This conserved structural architecture, termed the CCK (cyclic cystine knot), is responsible for their exceptional resistance to thermal, chemical and enzymatic degradation. Cyclotides have a variety of biological activities, but their insecticidal activities suggest that their primary function is in plant defence. In the present study, we determined the cyclotide content of the sweet violet Viola odorata, a member of the Violaceae family. We identified 30 cyclotides from the aerial parts and roots of this plant, 13 of which are novel sequences. The new sequences provide information about the natural diversity of cyclotides and the role of particular residues in defining structure and function. As many of the biological activities of cyclotides appear to be associated with membrane interactions, we used haemolytic activity as a marker of bioactivity for a selection of the new cyclotides. The new cyclotides were tested for their ability to resist proteolysis by a range of enzymes and, in common with other cyclotides, were completely resistant to trypsin, pepsin and thermolysin. The results show that while biological activity varies with the sequence, the proteolytic stability of the framework does not, and appears to be an inherent feature of the cyclotide framework. The structure of one of the new cyclotides, cycloviolacin O14, was determined and shown to contain the CCK motif. This study confirms that cyclotides may be regarded as a natural combinatorial template that displays a variety of peptide epitopes most likely targeted to a range of plant pests and pathogens.
Identification of a novel NADH-specific aldo-keto reductase using sequence and structural homologies
Authors: Di Luccio Eric , Elling Robert A. , Wilson David K.
Published: October 2006

The AKRs (aldo-keto reductases) are a superfamily of enzymes which mainly rely on NADPH to reversibly reduce various carbonyl-containing compounds to the corresponding alcohols. A small number have been found with dual NADPH/NADH specificity, usually preferring NADPH, but none are exclusive for NADH. Crystal structures of the dual-specificity enzyme xylose reductase (AKR2B5) indicate that NAD+ is bound via a key interaction with a glutamate that is able to change conformations to accommodate the 2′-phosphate of NADP+. Sequence comparisons suggest that analogous glutamate or aspartate residues may function in other AKRs to allow NADH utilization. Based on this, nine putative enzymes with potential NADH specificity were identified and seven genes were successfully expressed and purified from Drosophila melanogaster, Escherichia coli, Schizosaccharomyces pombe, Sulfolobus solfataricus, Sinorhizobium meliloti and Thermotoga maritima. Each was assayed for co-substrate dependence with conventional AKR substrates. Three were exclusive for NADPH (AKR2E3, AKR3F2 and AKR3F3), two were dual-specific (AKR3C2 and AKR3F1) and one was specific for NADH (AKR11B2), the first such activity in an AKR. Fluorescence measurements of the seventh protein indicated that it bound both NADPH and NADH but had no activity. Mutation of the aspartate into an alanine residue or a more mobile glutamate in the NADH-specific E. coli protein converted it into an enzyme with dual specificity. These results show that the presence of this carboxylate is an indication of NADH dependence. This should allow improved prediction of co-substrate specificity and provide a basis for engineering enzymes with altered co-substrate utilization for this class of enzymes.
Structural and kinetic analyses of the H121A mutant of cholesterol oxidase
Authors: Lim Louis , Molla Gianluca , Guinn Nicole , Ghisla Sandro , Pollegioni Loredano , Vrielink Alice
Published: October 2006

Cholesterol oxidase is a monomeric flavoenzyme that catalyses the oxidation of cholesterol to cholest-5-en-3-one followed by isomerization to cholest-4-en-3-one. The enzyme from Brevibacterium sterolicum contains the FAD cofactor covalently bound to His121. It was previously demonstrated that the H121A substitution results in a ≈100 mV decrease in the midpoint redox potential and a ≈40-fold decrease in turnover number compared to wild-type enzyme [Motteran, Pilone, Molla, Ghisla and Pollegioni (2001) Journal of Biological Chemistry 276, 18024–18030]. A detailed kinetic analysis of the H121A mutant enzyme shows that the decrease in turnover number is largely due to a corresponding decrease in the rate constant of flavin reduction, whilst the re-oxidation reaction is only marginally altered and the isomerization reaction is not affected by the substitution and precedes product dissociation. The X-ray structure of the mutant protein, determined to 1.7 Å resolution (1 Å≡0.1 nm), reveals only minor changes in the overall fold of the protein, namely: two loops have slight movements and a tryptophan residue changes conformation by a rotation of 180° about χ1 compared to the native enzyme. Comparison of the isoalloxazine ring moiety of the FAD cofactor between the structures of the native and mutant proteins shows a change from a non-planar to a planar geometry (resulting in a more tetrahedral-like geometry for N5). This change is proposed to be a major factor contributing to the observed alteration in redox potential. Since a similar distortion of the flavin has not been observed in other covalent flavoproteins, it is proposed to represent a specific mode to facilitate flavin reduction in covalent cholesterol oxidase.
A new group of exo-acting family 28 glycoside hydrolases ofAspergillus nigerthat are involved in pectin degradation
Authors: Martens-Uzunova Elena S. , Zandleven Joris S. , Benen Jaques A. E. , Awad Hanem , Kools Harrie J. , Beldman Gerrit , Voragen Alphons G. J. , Van Den Berg Johan A. , Schaap Peter J.
Published: October 2006

The fungus Aspergillus niger is an industrial producer of pectin-degrading enzymes. The recent solving of the genomic sequence of A. niger allowed an inventory of the entire genome of the fungus for potential carbohydrate-degrading enzymes. By applying bioinformatics tools, 12 new genes, putatively encoding family 28 glycoside hydrolases, were identified. Seven of the newly discovered genes form a new gene group, which we show to encode exoacting pectinolytic glycoside hydrolases. This group includes four exo-polygalacturonan hydrolases (PGAX, PGXA, PGXB and PGXC) and three putative exo-rhamnogalacturonan hydrolases (RGXA, RGXB and RGXC). Biochemical identification using polygalacturonic acid and xylogalacturonan as substrates demonstrated that indeed PGXB and PGXC act as exo-polygalacturonases, whereas PGXA acts as an exo-xylogalacturonan hydrolase. The expression levels of all 21 genes were assessed by microarray analysis. The results from the present study demonstrate that exo-acting glycoside hydrolases play a prominent role in pectin degradation.