bluuebunny/crossref_metadata_2025 huggingface dataset:
Channel sedimentation and erosion of the Jiangsu reach of the Yangtze River during the last 44 years
Authors: Jian Wang , Shibiao Bai , Ping Liu , Yanyan Li , Zhengrong Gao , Guixian Qu , Guangjie Cao
Published: July 2009

River channel sedimentation in the lower reaches of the Yangtze River can be affected by both changes in sea level and changes in solid discharge from the upper river. To evaluate dynamic changes of sedimentation and erosion in the Jiangsu reach of the Yangtze River (about 330 km in length) from 1959 to 2003, databases were designed and constructed using a digital elevation model (DEM) of channel topography based on the Jiangsu River Relief Map for 1959, 1970, 1985, 1992, and 2003. The results indicated that the main course of the Yangtze River in Jiangsu Province had experienced an obvious switch from sedimentation to erosion status around 1985 because of the decreasing amount of solid load from the upper parts of the river channel after that year. The sedimentation process in the main course of the Jiangsu reach of the Yangtze River demonstrated the propulsive process of ‘downstream‐ward aggradations.’ Between 1985 and 2003, the erosion rate of the lower segment was greater than those of the middle and upper segments; this is probably because both channel flow and tide current had influenced the lower segment. When channel flow combines with tide current in the same direction, channel erosion can be intensified, especially if there is a solid load shortage in the channel. Copyright © 2009 John Wiley & Sons, Ltd.
Suspended sediment transport and deposition over a dune: Río Paraná, Argentina
Authors: Kostaschuk Ray , Shugar Dan , Best Jim , Parsons Dan , Lane Stuart , Hardy Rich , Orfeo Oscar
Published: July 2009

Field data from the Rio Paraná, Argentina, are used to examine patterns of suspended sediment transport over a sand dune. Measurements of three‐dimensional velocity are made with an acoustic Doppler current profiler whilst suspended sediment concentration and particle size have been quantified using a laser in situ sediment scattering transmissometer. Suspended sediment concentration and streamwise and vertical sediment flux are highest close to the bed, with an upward vertical flux over the stoss side of the dune and downward flux over the lee side. Suspended sediment concentrations are higher over the crest compared with the trough and suspended sediment is coarsest near the bed. About 17% of the suspended‐load transported over the crest is deposited in the lee side before it reaches the trough. Most of this deposited sand is coarser sediment that originates close to the bed over the crest, a result consistent with simulations based on the model of Mohrig and Smith (Water Resources Research 1996; 32: 3207–3217) for the excursion lengths of sediment dispersed in the lee side of a dune. Copyright © 2009 John Wiley & Sons, Ltd.
Sulphonated Tetramethyl Poly(ether ether ketone)/Epoxy/Sulphonated Phenol Novolac Semi‐IPN Membranes for Direct Methanol Fuel Cells
Authors: Fu T. Z. , Liu J. , Cui Z. M. , Ni J. , Zhang G. , Yu H. B. , Zhao C. J. , Shi Y. H. , Na H. , Xing W.
Published: July 2009

The sulphonated phenol novolac (PNBS) which was used as a curing agent of epoxy was synthesised from phenol novolac (PN) and 1, 4‐butane sultone and confirmed by FTIR and 1H NMR. The degree of sulphonation (DS) in PNBS was calculated by 1H NMR. The semi‐IPN membranes composed of sulphonated tetramethyl poly(ether ether ketone) (STMPEEK) (the value of ion exchange capacity is 2.01 meq g–1), epoxy (TMBP) and PNBS were successfully prepared. The semi‐IPN membranes showed high thermal properties which were measured by differential scanning calorimeter (DSC) and thermogravimetric analyses (TGA). With the introduction of the cross‐linked TMBP/PNBS, the mechanical properties, dimensional stability, methanol resistance and oxidative stability of the membranes were improved in comparison to the pristine STMPEEK membrane. Although the proton conductivities of the semi‐IPN membranes were lower than those of the pristine STMPEEK membrane, the higher selectivity defined as the ratio of the proton conductivity to methanol permeability was obtained from the STMPEEK/TMBP/PNBS‐14 semi‐IPN membrane. The results indicated that the semi‐IPN membranes could be promising candidates for usage as proton exchange membranes in direct methanol fuel cells (DMFCs).
Volatility components: The term structure dynamics of VIX futures
Authors: Lu Zhongjin , Zhu Yingzi
Published: July 2009

In this study we empirically study the variance term structure using volatility index (VIX) futures market. We first derive a new pricing framework for VIX futures, which is convenient to study variance term structure dynamics. We construct five models and use Kalman filter and maximum likelihood method for model estimations and comparisons. We provide evidence that a third factor is statistically significant for variance term structure dynamics. We find that our parameter estimates are robust and helpful to shed light on economic significance of variance factor model. © 2009 Wiley Periodicals, Inc. Jrl Fut Mark 30:230–256, 2010
Detection of Lewy body disease in patients with late‐onset depression, anxiety and psychotic disorder with myocardial meta‐iodobenzylguanidine scintigraphy
Authors: Kobayashi Katsuji , Sumiya Hisashi , Nakano Hiroyuki , Akiyama Noriko , Urata Katsumi , Koshino Yoshifumi
Published: July 2009

Purpose

Lewy body disease (LBD) is comprised of a spectrum of diseases that includes Parkinson's disease (PD), PD dementia (PDD) and dementia with LBD (DLBD), an array of dementia, and motor symptoms. Low uptake of myocardial meta‐iodobenzylguanidine (MIBG) validates diagnosis of LBD. Psychiatric symptoms sometimes precede atypical Parkinsonian syndromes in LBD. Of 34 patients with low MIBG uptake, late‐onset depressive, anxiety, or psychotic symptoms were analyzed in term of clinical profiles.

Method

Thirty‐four patients were classed into three groups according to three main symptoms, 11 patients with visual hallucination (VH), 13 with depression‐anxiety (DA), and 10 with psychosis with cognitive disturbance (PCD). Cutoff values of heart‐to‐mediastinum (HM) ratio of MIBG were set at 1.78 in early phase or 1.68 in late phase.

Results

Group VH patients showed a trend toward higher age at onset and occipital lobe hypoperfusion. Group DA patients lacked central and core features of DLBD and five of them showed frontal lobe hypoperfusion. Group PCD patients had the highest frequencies of suggestive symptoms and UPDRS scores and showed temporal lobe hypoperfusion. HM ratio was not associated with clinical profiles of three groups. Cognitive function was more severely disturbed in atypical Parkinsonian syndrome cases at an initial visit.

Conclusion

Group VH was considered to DLBD, and Group PCD was regarded as PDD or DLBD with early psychotic presentation. Group DA has a possibility of early depression or anxiety disorder of LBD although it lacked DLBD criteria. Atypical Parkinsonian syndromes are associated with cognitive disturbance irrespective of psychiatric profiles. Copyright © 2009 John Wiley & Sons, Ltd.
Cancellation of EEG and MEG signals generated by extended and distributed sources
Authors: Ahlfors Seppo P. , Han Jooman , Lin Fa‐Hsuan , Witzel Thomas , Belliveau John W. , Hämäläinen Matti S. , Halgren Eric
Published: July 2009

Extracranial patterns of scalp potentials and magnetic fields, as measured with electro‐ and magnetoencephalography (EEG, MEG), are spatially widespread even when the underlying source in the brain is focal. Therefore, loss in signal magnitude due to cancellation is expected when multiple brain regions are simultaneously active. We characterized these cancellation effects in EEG and MEG using a forward model with sources constrained on an anatomically accurate reconstruction of the cortical surface. Prominent cancellation was found for both EEG and MEG in the case of multiple randomly distributed source dipoles, even when the number of simultaneous dipoles was small. Substantial cancellation occurred also for locally extended patches of simulated activity, when the patches extended to opposite walls of sulci and gyri. For large patches, a difference between EEG and MEG cancellation was seen, presumably due to selective cancellation of tangentially vs. radially oriented sources. Cancellation effects can be of importance when electrophysiological data are related to hemodynamic measures. Furthermore, the selective cancellation may be used to explain some observed differences between EEG and MEG in terms of focal vs. widespread cortical activity. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
The knowledge economy: emerging organizational forms, missing microfoundations, and key considerations for managing human capital
Authors: Felin Teppo , Zenger Todd R. , Tomsik Joshua
Published: July 2009

In this paper we outline an increasingly predominant, “communal,” perspective of the emerging knowledge economy and explore its emphasis on various nonmarket mechanisms of production. Although the communal perspective suggests organizational forms, governance mechanisms, and knowledge processes that may facilitate knowledge creation and knowledge transfer, we argue that it misses the seemingly contradictory trends of organizational disaggregation and the foundational importance of market mechanisms in knowledge creation. We contrast and partly reconcile these two perspectives of the knowledge economy and highlight key considerations related to the microfoundations of knowledge and human capital management. © 2009 Wiley Periodicals, Inc.
HR practices, interpersonal relations, and intrafirm knowledge transfer in knowledge‐intensive firms: a social network perspective
Authors: Kaše Robert , Paauwe Jaap , Zupan Nada
Published: July 2009

We adopt the social network perspective to develop a conceptual model and examine the relationship among human resource (HR) practices, interpersonal relations, and intrafirm knowledge transfer in knowledge‐intensive firms. Our results indicate that work design, along with training and development HR practices, can shape the structural relation. At the same time, both also exhibit potential for shaping affective and cognitive relations within a firm's social network. While the effects of work design along with training and development HR practices on intrafirm knowledge transfer are primarily mediated by interpersonal relations, we found some evidence for arguing that incentives and motivation HR practices directly affect intrafirm knowledge transfer. © 2009 Wiley Periodicals, Inc.
The vital liaison role of host country nationals in MNC knowledge management
Authors: Vance Charles M. , Vaiman Vlad , Andersen Torben
Published: July 2009

This paper broadens the conceptualization of multinational corporation (MNC) knowledge management to include the importance of active involvement in a liaison role by host country nationals (HCNs), particularly those working directly with expatriates. Based on our field research and work experience in international settings as well as current research literature, we identify and consider several beneficial components of this liaison role in local knowledge management, including cultural interpreter, communication facilitator, information resource broker, talent developer, and change partner. We also call for future research to help build upon our present model and to provide practical guidance in human resource (HR) policy and practice to help organizations take advantage of this potentially valuable liaison role. © 2009 Wiley Periodicals, Inc.
An optimised water intake with the presence of submerged vanes in irrigation canals
Authors: Moghadam Mehdi Karami , Keshavarzi Ali Reza
Published: July 2009

One of the problems at most water intakes is accumulation of sediment at the entrance and changing of flow talweg path at the water intake. Submerged vanes are small hydraulic structures that are used for flow and sediment control on the bed of rivers. The submerged vanes may be installed individually or in a group with different arrangements. In this study, a group of submerged vanes are installed at the entrance of a rounded edge 55° water intake with parallel and zigzag arrangements. The vanes' installation angles were selected to be 10, 20, 30 and 40° to the flow direction. The sedimentation pattern at the entrance of the water intake and the amount of sediment entering into the lateral channel were measured after experimental tests. From the experimental study, the optimum vane angle for the above‐specified water intake was found to be 30°. Also the parallel arrangement was found to be the best arrangement for the submerged vane. Copyright © 2009 John Wiley & Sons, Ltd.
Antibacterial coatings on titanium implants
Authors: Zhao Lingzhou , Chu Paul K. , Zhang Yumei , Wu Zhifen
Published: July 2009

Titanium and titanium alloys are key biomedical materials because of their good biocompatibility and mechanical properties. Nevertheless, infection on and around titanium implants still remains a problem which is usually difficult to treat and may lead to eventual implant removal. As a result, preventive measures are necessary to mitigate implant‐frelated infection. One important strategy is to render the implant surface antibacterial by impeding the formation of a biofilm. A number of approaches have been proposed for this purpose and they are reviewed in this article. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Characterization and cytocompatibility of surface modified polyamide66
Authors: Shen Juan , Li Yubao , Zuo Yi , Zou Qin , Li Jidong , Huang Di , Wang Xiaoyan
Published: July 2009

The chemical modification of polyamide66 (PA66) membrane by graft polymerization with methacrylic acid (MAA) was initiated under ultraviolet light. Subsequently, covalent immobilization of bioactive surface was obtained by coupling gelatin to the MAA graft chains with the aid of a water‐soluble carbodiimide (WSC). The existence of carboxyl groups grafted on PA66 surface was verified quantitatively by UV–vis spectroscopy. The chemical composition, surface topography, and wettability were investigated by Fourier transform infrared (FTIR) technique, X‐ray photoelectron spectroscopy, atomic force microscopy, and water contact angle (WCA) measurement. Results showed that the WCA changed from the original value of 67.5° to the minimum value of 30° after grafting with PMAA. Original PA66 displayed a smooth surface morphology [root mean square (RMS) roughness was around 16 nm]. The modified PA66 surface exhibited an increase in roughness (RMS roughness around 21 nm). Simultaneously, the original and modified PA66 membranes were cultured with MG63 cells to investigate their cytocompatibility. The in vitro biological evaluation demonstrated that the immobilization of gelatin on PA66 membrane acted as a good template for the attachment and proliferation of cells. Also, the less toxic reagents and the moderate reaction conditions involved will be very helpful for the introduction of functional groups onto polymer surface. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Porous keratin scaffold–promising biomaterial for tissue engineering and drug delivery
Authors: Srinivasan Balaji , Kumar Ramadhar , Shanmugam Kirubanandan , Sivagnam Uma Tiruchirapalli , Reddy Neelakanta Puily , Sehgal Praveen Kumar
Published: July 2009

A porous keratin scaffold, prepared from the reduced keratin solution, has shown good cell viability which makes it a potential candidate for cell seeding. An aqueous solution of reduced keratin was extracted from horn meal using a mixture of urea, sodium dodecyl sulfate, mercaptoethanol, and water at 60°C. The molecular mass of the extracted keratin is found to be ranging between 225 and 150 KDa. The CD spectrum of aqueous solution of keratin shows the presence of ∞‐helical structure with β‐turns as negative absorption band at 225 nm and as positive absorption band at 195 nm. The FTIR spectrum of the same confirms ∞‐helical structure with β‐turns. Its characteristic absorption bands are assigned mainly to the peptide bonds for amide I, II, and III respectively. DSC and TGA data of the reduced keratin peaks fall in region 200°C–250°C and 200°C–400°C temperatures, respectively. They correspond to the ∞‐helix denaturation of the material. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Immobilization, stabilization, and activation of human stem cell factor (SCF) on fragmin/protamine microparticle (F/P MP)‐coated plates
Authors: Kishimoto Satoko , Oonuma Fumie , Nakamura Shingo , Hattori Hidemi , Nakamura Shin‐ichiro , Mori Yasutaka , Tanaka Yoshihiro , Harada Yasuji , Tagawa Masahiro , Ishihara Masayuki
Published: July 2009

Fragmin (low‐molecular‐weight heparin)/protamine microparticles (F/P MPs) immobilize to culture plates, thereby retaining the binding of heparin‐binding cytokines such as human stem cell factor (SCF). The purpose of this study was to evaluate the ability of F/P MP‐coating to immobilize, stabilize, and enhance SCF‐activity. Cell assays showed that SCF and preimmobilized SCF on F/P MP‐coated plates significantly stimulated the proliferation of human erythroleukemia cell line TF‐1 in a concentration‐dependent manner. Heparin and fragmin enhanced SCF‐induced proliferation of chlorate‐treated TF‐1 cells, in which the biosynthesis of endogenous sulfated polysaccharides was blocked, on noncoated plates at a range of concentrations (2–8 μg/mL). However, heparin and fragmin had no effect on SCF‐induced proliferation of chlorate‐treated TF‐1 cells on F/P MP‐coated plates. The interaction of SCF with fragmin and F/P MPs prolonged the half‐life of SCF bioactivity, and immobilized and protected SCF from inactivation, such as from heat and proteolysis. These results suggest that F/P MP‐coated plates protect SCF and enhance its activity, and F/P MP‐coating provides an excellent biomaterial to immobilize and retain heparin‐binding cytokines, including SCF, in bioactive form for optimal expansion of hematopoietic cells. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Effects of evodiamine and rutaecarpine on the secretion of corticosterone by Zona fasciculata‐reticularis cells in male rats
Authors: Yu Po‐Ling , Chao Hsu‐Li , Wang Shyi‐Wu , Wang Paulus S.
Published: July 2009

Evodiamine (EVO) and rutaecarpine (RUT) are two bioactive alkaloid isolated from Chinese herb named Wu–Chu–Yu. Previous studies have shown that EVO and RUT possess thermoregulation, vascular regulation, anti‐allergic, anti‐nociceptive and anti‐inflammatory activities. The mechanisms of EVO and RUT effect on steroidogenesis are not clear. The goal of this study was to characterize the mechanism by which EVO and RUT affect corticosterone production in rat zona fasciculata‐reticularis (ZFR) cells. ZFR cells were isolated from adrenal glands of male rats and incubated with adrenalcorticotropin (ACTH, 10−9 M), forskolin (an adenylyl cyclase activator, 10−5 M), 8‐bromo‐adenosine 3′:5′‐cyclic monophosphate (8‐Br‐cAMP, a permeable cAMP analog, 10−4 M), or steroidogenic precursors including 25‐hydroxycholesterol, pregnenolone, progesterone, and deoxycorticosterone, 10−5 M each, in the presence or absence of EVO and RUT respectively (0–10−3 M) at 37°C for 1 h. The concentrations of corticosterone, pregnenolone and progesterone in the media were measured by radioimmunoassay. After administration of ZFR cells with EVO or RUT (10−4 M) for 60 and 120 min, Western blot analysis was employed to explore the influence of EVO and RUT on the expression of cytochrome P450 side chain cleavage enzyme (P450scc) and steroidogenic acute regulatory protein (StAR). EVO and RUT reduced both basal and ACTH‐, forskolin‐, as well as 8‐Br‐cAMP‐stimulated corticosterone production in rat ZFR cells. The enhanced corticosterone production caused by the administration of four steroidogenic precursors was decreased following EVO or RUT challenge. These results suggest that EVO and RUT inhibit corticosterone production in rat ZFR cells via a mechanism involving: (1) a decreased activity of cAMP‐related pathways; (2) a decreased activity of the steroidogenic enzymes, that is, 3β‐hydroxysteroid dehydrogenase (3β‐HSD) and 11β‐hydroxylase (P450c11), during steroidogenesis; and (3) an inhibition of StAR protein expression. J. Cell. Biochem. 108: 469–475, 2009. © 2009 Wiley‐Liss, Inc.
A role for SSRP1 in recombination‐mediated DNA damage response
Authors: Kumari Anuradha , Mazina Olga M. , Shinde Ujwal , Mazin Alexander V. , Lu Hua
Published: July 2009

A possible role for structure‐specific recognition protein 1 (SSRP1) in replication‐associated repair processes has previously been suggested based on its interaction with several DNA repair factors and the replication defects observed in SSRP1 mutants. In this study, we investigated the potential role of SSRP1 in association with DNA repair mediated by homologous recombination (HR), one of the pathways involved in repairing replication‐associated DNA damage, in mammalian cells. Surprisingly, over‐expression of SSRP1 reduced the number of hprt+ recombinants generated via HR both spontaneously and upon hydroxyurea (HU) treatment, whereas knockdown of SSRP1 resulted in an increase of HR events in response to DNA double‐strand break formation. In correlation, we found that the depletion of SSRP1 in HU‐treated human cells elevated the number of Rad51 and H2AX foci, while over‐expression of the wild‐type SSRP1 markedly reduced HU‐induced Rad51 foci formation. We also found that SSRP1 physically interacts with a key HR repair protein, Rad54 both in vitro and in vivo. Further, branch migration studies demonstrated that SSRP1 inhibits Rad54‐promoted branch migration of Holliday junctions in vitro. Taken together, our data suggest a functional role for SSRP1 in spontaneous and replication‐associated DNA damage response by suppressing avoidable HR repair events. J. Cell. Biochem. 108: 508–518, 2009. © 2009 Wiley‐Liss, Inc.
Rapamycin impairs trabecular bone acquisition from high‐dose but not low‐dose intermittent parathyroid hormone treatment
Authors: Niziolek P.J. , Murthy S. , Ellis S.N. , Sukhija K.B. , Hornberger T.A. , Turner C.H. , Robling A.G.
Published: July 2009

The osteo‐anabolic effects of intermittent parathyroid hormone (PTH) treatment require insulin‐like growth factor (IGF) signaling through the IGF‐I receptor. A major downstream target of the IGF‐I receptor (via Akt) is the mammalian target of rapamycin (mTOR), a kinase involved in protein synthesis. We investigated whether the bone‐building effects of intermittent PTH require functional mTOR signaling. Mice were treated with daily PTH 1–34 (0, 10, 30, or 90 µg/kg) for 6 weeks in the presence or absence of rapamycin, a selective inhibitor of mTOR. We found that all PTH doses were effective in enhancing bone mass, whether rapamycin was present or not. Rapamycin had little to no effect on the anabolic response at low (10 µg) PTH doses, small effects in a minority of anabolic measures at moderate doses (30 µg), but the anabolic effects of high‐dose PTH (90 µg) were consistently and significantly suppressed by rapamycin (∼4–36% reduction). Serum levels of Trap5b, a marker of resorption, were significantly enhanced by rapamycin, but these effects were observed whether PTH was absent or present. Our data suggest that intermittent PTH, particularly at lower doses, is effective in building bone mass in the presence of rapamycin. However, the full anabolic effects of higher doses of PTH are significantly suppressed by rapamycin, suggesting that PTH might normally activate additional pathways (including mTOR) for its enhanced high‐dose anabolic effects. Clinical doses of intermittent PTH could be an effective treatment for maintaining or increasing bone mass among patients taking rapamycin analogs for unrelated health issues. J. Cell. Physiol. 221: 579–585, 2009. © 2009 Wiley‐Liss, Inc.
Is there a role for thyroid hormone on spermatogenesis?
Authors: Wagner Marcia Santos , Wajner Simone Magagnin , Maia Ana Luiza
Published: July 2009

Appropriate level of thyroid hormone is essential for normal development and metabolism in most vertebrate tissues and altered thyroid status impacts adversely on them. For many years the testis was regarded as a thyroid hormone unresponsive organ, but consistent evidence accumulated in the past two decades has definitively changed this classical view. Currently, the concept that thyroid hormone plays a critical role in testis development, in rats and other vertebrate species, is clearly established. Although the effects of thyroid hormone on Sertoli and Leydig cells in the immature testis are well described, its role on the adult organ remains controversial. In this review, we summarize and discuss the recent development on the thyroid hormone effects in immature and adult testes. Particularly, we have attempted to address the role of thyroid hormone in the regulation of spermatogenesis, emphasizing recent data that suggest its involvement in germ cells differentiation and survival. Microsc. Res. Tech. 2009. © 2009 Wiley‐Liss, Inc.
The relationship of heart function to temperature in Drosophila melanogaster and its heritability
Authors: Jennings Tricia , Ringo John , Dowse Harold
Published: July 2009

We measured heart rate and rhythmicity (regularity) of heartbeat in Drosophila melanogaster at five different temperatures (20, 25, 30, 35, and 37°C) for a Florida population and estimated the narrow‐sense heritability of both traits. Heritability of heart rate ranged from 0.17 to 0.24, but was statistically significant only at 20° (h2=0.24) and at 30° (h2=0.23). The heritability of heartbeat rhythmicity ranged from –0.034 to 0.11, and was not significant at any temperature. Heart rate increased linearly with increasing temperature; the temperature‐dependence of heart rate was itself heritable (h2=0.29). Heart rhythmicity varied curvilinearly and was well‐represented by a parabolic function, peaking at about 27° which suggests a temperature optimum. The regularity of the heartbeat did not covary with heart rate except at 20°. Neither heart rate nor regularity covaried with the change in heart rate with temperature. For this population of D. melanogaster, we conclude that there is substantial genetic variation for the mechanism whereby the cardiac pacemaker reacts to changes in temperature, but not for the cardiac pacemaker's rhythmicity. The small values of h2 for temperature‐specific heart rate and heartbeat rhythmicity suggest that these traits have been subjected to natural selection. J. Exp. Zool. 311A: 689–696, 2009. © 2009 Wiley‐Liss, Inc.
The anterior midgut of larval yellow fever mosquitoes (Aedes aegypti): effects of amino acids, dicarboxylic acids, and glucose on the transepithelial voltage and strong luminal alkalinization
Authors: Izeirovski Sejmir , Moffett Stacia B. , Moffett David F. , Onken Horst
Published: July 2009

Isolated anterior midguts of larval Aedes aegypti were bathed in aerated mosquito saline containing serotonin (0.2 µmol L−1) and perfused with NaCl (100 mmol L−1). The lumen negative transepithelial voltage (Vte) was measured and luminal alkalinization was determined through the color change of luminal m‐cresol purple from yellow to purple after luminal perfusion stops. Addition of 10 mmol L−1 amino acids (arginine, glutamine, histidine or proline) or dicarboxylic acids (malate or succinate) to the luminal perfusate resulted in more negative Vte values, whereas addition of glucose was without effect. In the presence of TRIS chloride as luminal perfusate, addition of nutrients did not change Vte. These results are consistent with Na+‐dependent absorption of amino acids and dicarboxylic acids. Effects of serotonin withdrawal indicated that nutrient absorption is stimulated by this hormone. Strong luminal alkalinization was observed with mosquito saline containing serotonin on the hemolymph‐side and 100 mmol L−1 NaCl in the lumen, indicating that alkalinization does not depend on luminal nutrients. Omission of glucose or dicarboxylic acids from the hemolymph‐side solution had no effect on luminal alkalinization, whereas omission of amino acids significantly decelerated it. Re‐addition of amino acids restored alkalinization, suggesting the involvement of amino acid metabolism in luminal alkalinization. J. Exp. Zool. 311A: 719–726, 2009. © 2009 Wiley‐Liss, Inc.
A preliminary analysis of gene pleiotropy estimated from protein sequences
Authors: Su Zhixi , Zeng Yanwu , Gu Xun
Published: July 2009

Biologists have long recognized the importance of gene pleiotropy, that is, single genes affect multiple traits, which is one of the most commonly observed attributes of genes. Yet the extent of gene pleiotropy has been seriously under‐explored. Theoretically, Fisher's model assumed a universal pleiotropy, that is, a mutation can potentially affect all phenotypic traits. On the other hand, experimental assays of a gene usually showed a few distinct phenotypes. Our recent work provides a new approach by estimating the degree of pleiotropy effectively from the phylogenetic sequence analysis. In this article, we estimated the effective gene pleiotropy for 321 vertebrate genes, and found that a gene typically affects 6–7 molecular phenotypes that correspond to the components of organismal fitness, respectively. The positive correlation of gene pleiotropy with the number of Gene Ontology biological processes, as well as the expression broadness provides a biological basis for the sequence‐based estimation of gene pleiotropy. On the other hand, the degree of gene pleiotropy has been restricted to a digital number of molecular phenotypes, indicating that some cautions are needed for theoretical analysis of gene pleiotropy based on the assumption of universal pleiotropy. J. Exp. Zool. (Mol. Dev. Evol.) 314B:115–122, 2010. © 2009 Wiley‐Liss, Inc.
The role of regulatory fit in visionary leadership
Authors: Stam Daan Alexander , van Knippenberg Daan , Wisse Barbara
Published: July 2009

It is generally argued that leader visions motivate followers by focusing on reaching desirable end‐states. However, it has also been suggested that visions may motivate followers by focusing on avoiding undesirable situations. In this paper we investigate the effects of appeals that focus on preventing an undesirable situation (i.e., prevention‐appeals) as well as appeals that focus on promoting a desirable situation (i.e., promotion‐appeals). We argue that the effectiveness of promotion‐ and prevention‐appeals is contingent on follower regulatory focus. In two experiments we show that prevention‐appeals lead to better performance than promotion‐appeals for more prevention‐focused followers, while the reverse is true for more promotion‐focused followers. We find this pattern for a dispositional measure of follower regulatory focus (Study 1) as well as for a manipulation of follower regulatory focus (Study 2). Copyright © 2009 John Wiley & Sons, Ltd.
Does participative leadership enhance work performance by inducing empowerment or trust? The differential effects on managerial and non‐managerial subordinates
Authors: Huang Xu , Iun Joyce , Liu Aili , Gong Yaping
Published: July 2009

We examined whether participative leadership behavior is associated with improved work performance through a motivational process or an exchange‐based process. Based on data collected from 527 employees from a Fortune 500 company, we found that the link between superiors' participative leadership behaviors and subordinates' task performance and organizational citizenship behavior toward organizations (OCBO) was mediated by psychological empowerment (motivational mediator) for managerial subordinates. Yet, for non‐managerial subordinates such as supporting and front‐line employees, the impact of participative leadership on task performance and OCBO was mediated by trust‐in‐supervisor (exchange‐based mediator). Implications for theories and practices are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Comparative analysis of the long‐term variability of winter surface temperature in the Black and Aegean Seas during 1982–2004 associated with the large‐scale atmospheric forcing
Authors: Kazmin Alexander S. , Zatsepin Andrei G. , Kontoyiannis Harilaos
Published: July 2009

Satellite and reanalysis data for the period 1982–2004 were used to study the long‐term variability of the winter‐mean sea surface temperature (SST) in the Black and Aegean Seas and its connection with the major atmospheric forcing: surface air temperature (SAT), surface wind and North Atlantic Oscillation (NAO) and East Atlantic‐West Russia (EAWR) teleconnection patterns. In spite of some differences, the general tendencies of SST variability in both basins are similar. The major climatic event (i.e. SST decreases below the climatic mean followed by the sharp increase of SST, occurred during the period 1986–1999) and its connection with the atmospheric forcing are evident both in the Black and Aegean Seas. During the investigated period, the south‐western wind regime occurred over the Black Sea and the north‐eastern wind regime over the Aegean. It is shown that the variability of the meridional component of the surface wind (which provides the most of the atmospheric heat transport into the basins) is well correlated with the large‐scale atmospheric patterns (NAO and EAWR). The major difference is that in the Black Sea the NAO intensification/weakening results in the weakening/strengthening of the southern wind, whereas in the Aegean Sea EAWR/NAO intensification/weakening produce strengthening/weakening of the northern wind. The long‐term variability of the SST is well correlated with the variability of the SAT, which in turn is highly correlated with the meridional component of the surface wind. However, a remarkable feature is that in the Black Sea an increase/decrease of the SAT is associated with the strengthening/weakening of the southern wind. On the contrary, in the Aegean Sea, an increase/decrease of the SAT is associated with the weakening/strengthening of the northern wind. The simple basic scheme of influence of the large‐scale atmospheric forcing on the long‐term SST variability during the positive NAO and EAWR phase is proposed. Copyright © 2009 Royal Meteorological Society
Plant‐compositional effects on surface runoff and sediment yield in subalpine grassland
Authors: Merz Andreas , Alewell Christine , Hiltbrunner Erika , Bänninger Dominik
Published: July 2009

Soil erosion such as sheet erosion is frequently encountered in subalpine grassland in the Urseren Valley (Swiss Central Alps). Erosion damages have increased enormously in this region during the last 50 y, most likely due to changes in land‐use practices and due to the impact of climatic changes. In order to estimate the effect of vegetation characteristics on surface runoff and sediment loss, we irrigated 22 pasture plots of 1 m2 during 1 h at an intense rain rate of 50 mm h–1 in two field campaigns using a portable rain simulator. The rain‐simulation plots differed in plant composition (herb versus grass dominance) and land‐use intensity but not in plant cover (>90%) nor in soil conditions. Prior to the second rain‐simulation campaign, aboveground vegetation was clipped in order to simulate intense grazing. The generated surface runoffs, sediment loss, relative water retention in the aboveground vegetation, and changes in soil moisture were quantified. Runoff coefficient varied between 0.1% and 25%, and sediment loss ranged between 0 and 0.053 g m–2. Thus, high infiltration rates and full vegetation cover resulted in very low erosion rates even under such extreme rain events. Surface runoff did not differ significantly between herb‐ and grass‐dominated plots. However, clipping had a notable effect on surface runoff in the test plots under different land‐use intensity. In plots without or with intensive use, surface runoff decreased after clipping whereas in extensively used plots, surface runoff increased after the clipping. This opposite effect was mainly explained by higher necromass and litter presence at the extensively used plots after the clipping treatment. The results obtained here contribute to a better understanding of the importance of vegetation characteristics on surface‐runoff formation, thus, on soil‐erosion control. Overall, we delineate vegetation parameters to be crucial in soil‐erosion control which are directly modified by the land‐use management.
Soil‐phosphorus distribution and availability as affected by greenhouse subsurface irrigation
Authors: Wang Yaosheng , Zhang Yulong
Published: July 2009

Vertical distribution and plant availability of soil P under subsurface irrigation were investigated in a 5‐year tomato‐grown‐greenhouse experiment. Irrigation was applied when soil water condition reached the predefined maximum allowable depletion (MAD) for different treatments, e.g., –10 kPa, –16 kPa, –25 kPa, –40 kPa, and –63 kPa. Results show that P distribution with soil depth was significantly affected by irrigation schedules. The general trend is that concentrations of soil total P and inorganic P were greater in topsoil than in subsoil, whereas the concentrations of soil organic P were larger at the depths of 0–10 cm, 30–40 cm, and 40–60 cm than at other soil depths. Comparison of different irrigation schedules indicates that more soil organic P was retained in the soils under the MAD of –25 kPa, –40 kPa, and –63 kPa, implying that irrigation of relatively low frequency and large water quantity of each irrigation event favored the accumulation of organic P in soils. In addition, we found that the concentrations of plant‐available P decreased with soil depth and were largest under the MAD of –16 kPa and –25 kPa. This result suggests that irrigation of relatively high frequency and low water quantity of each irrigation event led to greater P availability for plant uptake. Overall, this study suggests that the transformation and plant availability of soil P can be manipulated, to some degree, by soil‐water management. Maximum allowable depletion controlled between –16 kPa and –25 kPa could result in high availability of soil P in clay‐textured soils.
Experimental and theoretical investigation of the apomorphine Raman spectrum
Authors: Lucotti A. , Casella M. , Tommasini M. , Gramatica F. , Di Fabrizio E. , Zerbi G.
Published: July 2009

Apomorphine (aporphine‐10,11‐diol, CA Registry Number 58004) is a non‐narcotic derivative of morphine discovered in 1869 by Mattheisen1 and it is a well‐known potent short‐acting dopamine agonist at D1 and D2 dopamine receptors, typically used in the treatment of patients with advanced Parkinson's disease (PD). To identify the unknown vibrational spectrum of this compound, apomorphine bare salt and its commercial drug formulation (Apofin) were examined by means of Raman spectroscopy. In the Raman spectrum of apomorphine (both bare salt and commercial drug), two strong characteristic signals were found, which were assigned with the help of first‐principles calculations: the band at 1589 cm−1 (assigned to the stretching mode of the B aromatic ring coupled with CH in‐plane bending) and the band at 1302 cm−1 (assigned to O‐H in‐plane bending and CH2 twisting and wagging vibrations). Copyright © 2009 John Wiley & Sons, Ltd.
Rapid separation of three glucosylated resveratrol analogues from the invasive plant Polygonum cuspidatum by high‐speed countercurrent chromatography
Authors: Fan Peihong , Marston Andrew , Hay Anne‐Emmanuelle , Hostettmann Kurt
Published: July 2009

Three glucosylated resveratrol analogues (piceid, piceatannol glucoside, resveratroloside) were successfully isolated from the crude MeOH extract of the invasive plant species Polygonum cuspidatum by semi‐preparative high‐speed countercurrent chromatography with a two‐phase solvent system composed of cyclohexane‐ethyl acetate‐methanol‐water (1:5:1:5, v/v/v/v). Piceid (23 mg), resveratroloside (17 mg), piceatannol glucoside (15 mg) of purities over 80% were isolated from 500 mg crude MeOH extract in one step. Subsequent passage over a SPE column was used to quickly bring their purities to over 90%. The purities were determined by HPLC analysis and their structures were elucidated by proton nuclear magnetic resonance (1H‐NMR), HMBC, ESI‐MS and HR‐MS.
Robustness of the co‐ion transfer ratio in capillary electrophoresis
Authors: Erny Guillaume L. , Esteves Valdemar I.
Published: July 2009

In CE, indirect detection mode often exhibits a lower precision than its direct counterpart. Although various explanations have already been advanced, in this work, we aimed to investigate if this is due, in part, to problems of robustness of the co‐ion transfer ratio (TR), thus being inherent to this particular detection scheme. This was investigated using simulation software that allows an accurate control of various parameters and validated using acetic acid as a test compound. It was conclusively demonstrated that the TR could vary by more than 6% when the concentration of one of the ions in the BGE was changed by as few as 1%. The presence of a system peak seems to be particularly damaging as it has been shown that the TR of peaks whose mobilities differ by more than 0.5×10–8 m2 V–1 s–1 from one of the system peaks, still have a relatively low robustness.
Occurrence and behavior of system peaks in RP HPLC with solely aqueous mobile phases
Authors: Kalíková Květa , Hruška Vlastimil , Svobodová Jana , Chudoba Richard , Gaš Bohuslav , Tesařová Eva
Published: July 2009

System peaks are important but often also disturbing phenomena occurring in separation systems. Behavior of system peaks was studied in reversed phase high performance liquid chromatography (RP HPLC) systems consisting of an RP Amide C16 column and aqueous solutions of organic acids with alkaline metal hydroxides as mobile phases. Binary mobile phases, composed of benzoic acid and lithium hydroxide (LiOH) or cesium hydroxide (CsOH), yielded two system peaks. The first peak was stationary and the second one moved with dilution of the mobile phase or with changes of the alkaline metal hydroxide concentration. The latter changes affected dissociation of the benzoic acid present in the mobile phase and thereby its retention. The presumption that the first system peak is not influenced by the type of alkaline metal cation and that it is related to the non‐adsorbed component of the mobile phase was confirmed by a cyclic procedure. Three‐component mobile phases composed of benzoic acid, tropic acid, and a hydroxide gave rise to three system peaks as expected. The first peak was again stationary and the two others shifted depending on the concentration variation of both acids. Resonance causing a zigzag peak, well described in capillary zone electrophoresis (CZE), was observed if 1‐pentanol was injected into a chromatographic system with one‐component mobile phase.
Laser induced explosive vapor and cavitation resulting in effective irrigation of the root canal. Part 1: A visualization study
Authors: Blanken Jan , De Moor Roeland Jozef Gentil , Meire Maarten , Verdaasdonk Rudolf
Published: July 2009

Background and Objectives

Limited information exists regarding the induction of explosive vapor and cavitation bubbles in an endodontic rinsing solution. It is also not clear whether a fiber has to be moved in the irrigation solution or can be kept stationary. No information is available on safe power settings for the use of cavitation in the root canal. This study investigates the fluid movements and the mechanism of action caused by an Er,Cr:YSGG laser in a transparent root model.

Material and Methods

Glass models with an artificial root canal (15 mm long, with a 0.06 taper and apical diameter of 400 µm) were used for visualization and registration with a high‐speed imaging technique (resolution in the microsecond range) of the creation of explosive vapor bubbles with an Er,Cr:YSGG laser at pulse energies of 75, 125, and 250 mJ at 20 Hz using a 200 µm fiber (Z2 Endolase). Fluid movement was investigated by means of dyes and visualization of the explosive vapor bubbles, and as a function of pulse energy and distance of the fiber tip to the apex.

Results

The recordings in the glass model show the creation of expanding and imploding vapor bubbles with secondary cavitation effects. Dye is flushed out of the canal and replaced by surrounding fluid. It seems not necessary to move the fiber close to the apex.

Conclusion

Imaging suggests that the working mechanism of an Er,Cr:YSGG laser in root canal treatment in an irrigation solution can be attributed to cavitation effects inducing high‐speed fluid motion into and out the canal. Lasers Surg. Med. 41:514–519, 2009. © 2009 Wiley‐Liss, Inc.
A Numerical Model for the Optimal Vulcanization of 2D Polar Rubber Compounds Using Microwaves
Authors: Milani Gabriele , Milani Federico
Published: July 2009

A numerical model is presented for the optimal vulcanization of 2D extruded polar rubber with microwaves and peroxides. Magnetron power and curing time are used as the input production parameters, and the output mechanical property selected for optimization is the average tensile strength of the item. A 2D thick weather strip is analyzed to validate the model. The electric field is evaluated by means of Yee cells (FDTD approach) and suitably inserted in Fourier's heat transmission law, thus allowing point‐by‐point temperature profiles to be determined. The temperature is then used to evaluate the degree of peroxidic reticulation, and thus the final tensile strength. A so‐called alternating tangent approach based on the bisection method is finally proposed to estimate the optimal magnetron power and curing time.

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Proof of principle: The effect of antimuscarinics on bladder filling sensations in healthy subjects—A placebo controlled double blind investigation using 4 and 8 mg tolterodine extended release
Authors: Mehnert Ulrich , Reitz André , Youssef Sumaya Abo , Schurch Brigitte
Published: July 2009

Aims

There is evidence that antimuscarinic drugs have depressant influence not only on bladder muscle activity, but also on bladder sensations. The aim of this study was to evaluate the effect of a single dose tolterodine extended release (ER) 4 and 8 mg on bladder sensations during filling cystometry.

Methods

After approval of the local ethics committee, 30 healthy female subjects (23.7 ± 2.3 years) were included and randomly assigned to three groups: (A) placebo, (B) tolterodine ER 4 mg, and (C) tolterodine ER 8 mg in a double blind manner. Measurements were performed at baseline and 4 hr postmedication in each group, consisting of: (1) Filling cystometry with 25 ml/min at which subjects had to indicate first sensation of filling (FSF), first desire to void (FDV), and strong desire to void (SDV). (2) Uroflowmetry and ultrasound control for residual urine.

Results

In the placebo group, filling volumes at FDV and SDV decreased significantly posttreatment. This effect could not be observed for the tolterodine 8 mg group and only at SDV in the 4 mg group. No significant difference between groups was found regarding uroflowmetry parameters and postvoid residual volume.

Conclusions

No increase of filling volumes in healthy subjects could be observed with tolterodine. However, the results suggest that tolterodine is able to alleviate irritation caused by repeated catheterization and cystometry. There was no significant influence of tolterodine ER 4 or 8 mg on voiding function. Neurourol. Urodynam. 29:464–469, 2010. © 2009 Wiley‐Liss, Inc.