bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Community Dynamics of a Continuous Mesophilic Anaerobic Biogas Digester Fed with Sugar Beet Silage
Authors: Demirel B. , Neumann L. , Scherer P.
Published: August 2008

The aim of the study was to investigate the long‐term fermentation of an extremely sour substrate without any addition of manure. In the future, the limitation of manure and therefore the anaerobic digestion of silage with a very low buffering capacity will be an increasing general bottleneck for energy production from renewable biomass. During the mesophilic anaerobic digestion of sugar beet silage (without top and leaves) as the sole substrate (without any addition of manure), which had an extreme low pH of around 3.3, the highest specific gas production rate (spec. GPR) of 0.72 L/g volatile solids (VS) d was achieved at a hydraulic retention time (HRT) of 25 days compared to an organic loading rate (OLR) of 3.97 g VS/L d at a pH of around 6.80. The methane (CH4) content of the digester ranged between 58 and 67 %, with an average of 63 %. The use of a new charge of substrate (a new harvest of the same substrate) with higher phosphate content improved the performance of the biogas digester significantly. The change of the substrate charge also seemed to affect the methanogenic population dynamics positively, thus improving the reactor performance. Using a new substrate charge, a further decrease in the HRT from 25 to 15 days did not influence the digester performance and did not seem to affect the structure of the methanogenic population significantly. However, a decrease in the HRT affected the size of the methanogenic population adversely. The lower spec. GPR of 0.54 L/g VS d attained on day 15 of the HRT could be attributed to a lower size of methanogenic population present in the anaerobic digester during this stage of the process. Furthermore, since sugar beet silage is a relatively poor substrate, in terms of the buffering capacity and the availability of nutrients, an external supply of buffering agents and nutrients is a prerequisite for a safe and stable digester operation.
Enhancement of the NAD(P)(H) Pool in Saccharomyces cerevisiae
Authors: Knepper A. , Schleicher M. , Klauke M. , Weuster‐Botz D.
Published: August 2008

Asymmetric biosyntheses allow for an efficient production of chiral building blocks. The application of whole cells as biocatalysts for asymmetric syntheses is advantageous because they already contain the essential coenzymes NAD(H) or NADP(H), which additionally can be regenerated in the cells. Unfortunately, reduced catalytic activity compared to the oxidoreductase activity is observed in many cases during whole‐cell biotransformation. This may be caused by low intracellular coenzyme pool sizes and/or a decline in intracellular coenzyme concentrations. To enhance the intracellular coenzyme pool sizes, the effects of the precursor metabolites adenine and nicotinic acid on the intracellular accumulation of NAD(H) and NADP(H) were studied in Saccharomyces cerevisiae. Based on the results of simple batch experiments with different precursor additions, fed‐batch processes for the production of yeast cells with enhanced NAD(H) or enhanced NADP(H) pool sizes were developed. Supplementation of the feed medium with 95 mM adenine and 9.5 mM nicotinic acid resulted in an increase of the intracellular NAD(H) concentration by a factor of 10 at the end of the fed‐batch process compared to the reference process. The final NAD(H) concentration remains unchanged if the feed medium was solely supplemented with 95 mM adenine, but intracellular NADP(H) was increased by a factor of 4. The effects of NADP(H) pool sizes on the asymmetric reduction of ethyl‐4‐chloro acetoacetate (CAAE) to the corresponding (S)‐4‐chloro‐3‐hydroxybutanoate (S‐CHBE) was evaluated with S. cerevisiae FasB His6 as an example. An intracellular threshold concentration above 0.07 mM NADP(H) was sufficient to increase the biocatalytic S‐CHBE productivity by 25 % compared to lower intracellular NADP(H) concentrations.
Testing the Efficiency of Biofilms Formed on Natural Substratum, Coyonoxtle (Opuntia Imbricata), for the Anaerobic Degradation of Aromatic Compounds
Authors: Chávez J. A. M. , Balagurusamy N. , Rodríguez‐Martínez J.
Published: August 2008

In this study, previously developed anaerobic microbial consortia capable of degrading aromatic compounds were used to develop biofilms on a natural material, coyonoxtle (Opuntia imbricata), which is abundantly available in North Mexico. The developed biofilms were evaluated for their efficiency in the biodegradation of different aromatic compounds, viz., phenol, catechol, 4‐aminobenzoic acid and p‐phenylenediamine in batch reactors. It was observed that in reactors with biofilms a more than 90 % COD removal and a concomitant production of methane could be obtained. But the rate of COD removal and methane production varied depending upon the type of biofilm used. Rumen‐derived biofilms demonstrated a lag phase of 7 to 14 days, whereas sludge‐derived biofilms exhibited a lag phase of more than three weeks. Between the biofilms from two sources, rumen‐derived biofilms showed a higher COD removal and methane production than sludge‐derived biofilms. When biofilm reactors were compared with reactors containing freely suspended consortia, it was evident that both rumen– and sludge‐derived biofilm reactors exhibited a two‐fold higher COD removal and methane production. Based on the results obtained, it can be concluded that coyonoxtle has the potential for use as a substratum.
Residual compressive behavior of alkali‐activated concrete exposed to elevated temperatures
Authors: Guerrieri Maurice , Sanjayan Jay , Collins Frank
Published: August 2008

This paper reports the effect of elevated temperature exposures, up to 1200°C , on the residual compressive strengths of alkali‐activated slag concrete (AASC) activated by sodium silicate and hydrated lime; such temperatures can occur in a fire. The strength performance of AASC in the temperature range of 400–800°C was similar to ordinary Portland cement concrete and blended slag cement concrete, despite the finding that the AASC did not contain Ca(OH)2 , which contributes to the strength deterioration at elevated temperatures for Ordinary Portland Cement and blended slag cement concretes. Dilatometry studies showed that the alkali‐activated slag (AAS) paste had significantly higher thermal shrinkage than the other pastes while the basalt aggregate gradually expanded. This led to a higher thermal incompatibility between the AAS paste and aggregate compared with the other concretes. This is likely to be the governing factor behind the strength loss of AASC at elevated temperatures. Copyright © 2008 John Wiley & Sons, Ltd.
The employment of part‐time faculty at community colleges
Authors: Christensen Chad
Published: August 2008

It is important to understand the reasons that community colleges hire part‐time faculty, their effectiveness, and the working conditions they face at two‐year institutions.
When less is more: The effect of devolution on HR's strategic role and construed image
Authors: Kulik Carol T. , Perry Elissa L.
Published: August 2008

This research explores the possibility that devolving people‐management activities to line managers might transform an HR unit and improve its reputation within its organization. We examined the effect of devolving people‐management responsibilities to line managers on HR managers' construed image—their perceptions of the internal reputation of the HR unit. Results revealed that a devolution strategy had a positive effect on HR managers' perceptions of their unit's reputation among line managers and that this effect was partially mediated by changes in the HR function. Specifically, devolution increased HR's involvement in the operation of business units and in the organization's strategic planning. In turn, this change in HR's strategic role resulted in a more positive construed image for members of the HR unit. © 2008 Wiley Periodicals, Inc.
Non‐invasive multiphoton imaging of extracellular matrix structures
Authors: Schenke‐Layland Katja
Published: August 2008

Multiphoton microscopy has become a powerful method for the artifact‐free, nondestructive evaluation of deep‐tissue cells and extracellular matrix (ECM) structures in their native environment. By interacting with highly non‐centrosymmetric molecular assemblies such as fibrillar collagen, the non‐linear process called second harmonic generation (SHG) has also proven to be an important diagnostic tool for the visualization of ECM compartmentsin situwith submicron resolution without the need for tissue processing. This review reports on applications of multiphoton‐induced autofluorescence and SHG microscopy to identify collagen and elastic fiber orientation in native, tissue‐engineered and processed, as well as healthy and diseased, tissues and organs. SHG signal profiling was used to quantify ECM damage in various cardiovascular and exocrine tissues, as well as cartilage. These novel imaging modalities open the general possibility of high‐resolutionin situand more importantin vivoimaging of ECM structures, cells and intracellular organelles in living intact tissues. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Auditing in China
Authors: Chong H. Gin
Published: August 2008

The Chinese auditing standards have undergone many changes in recent years. These changes intend to harmonize the internal auditing practices with the international auditing approaches. The speed of transformation is remarkable. Despite this, there remain many challenging issues that need the attention of both the Chinese auditing profession and the Ministry of Finance (MoF). © 2008 Wiley Periodicals, Inc.
Molecular characterization of enteric viral agents from children in northern region of Ghana
Authors: Silva Paula Andreia , Stark Klaus , Mockenhaupt Frank P. , Reither Klaus , Weitzel Thomas , Ignatius Ralf , Saad Eiman , Seidu‐Korkor Andrew , Bienzle Ulrich , Schreier Eckart
Published: August 2008

Viral gastrointestinal infections are among the most important causes of childhood morbidity and mortality, especially in non‐industrialized countries. The objective of this study was the molecular characterization of rotaviruses, noroviruses, adenoviruses, astroviruses, and enteroviruses obtained from 367 children in the Northern Region of Ghana. One hundred and forty‐two rotavirus‐positive stool samples were examined. The most frequent type identified was G1P[8] occurring in 80% of the cases. Of 27 norovirus positive samples, 5 isolates belonged to genogroup I and 22 to genogroup II. Adenoviruses were detected in 73 samples; 23.3% of these belonged to genogroup F, 31.5% to D, 17.8% to A, 15.1% to C, and 12.3% to B. Astrovirus typing of 12 positive samples displayed a distribution into four different genotypes: five sequences clustered with AstV‐8, four with AstV‐2, two with AstV‐5, and one with AstV‐6. Twenty‐three different enterovirus types were identified in 45 positive samples, coxsackievirus A24 being the most frequent pathogen (18%). This first, comprehensive molecular characterization of enteric viruses in northern Ghana provides baseline data for the molecular epidemiology of these pathogens and immunisation strategies. The available rotavirus vaccines cover the predominant G1P[8] type and would reduce substantially disease burden in that area. J. Med. Virol. 80:1790–1798, 2008. © 2008 Wiley‐Liss, Inc.
Neutralizing antibody response variation against dengue 3 strains
Authors: Alvarez Mayling , Pavon‐Oro Alequis , Rodriguez‐Roche Rosmari , Bernardo Lídice , Morier Luís , Sanchez Lizet , Alvarez Angel M. , Guzmán Maria G.
Published: August 2008

To evaluate the neutralizing antibody activity of a human sera panel against seven strains of the homotypic virus. Sera were collected from DENV‐3 immune individuals. Two DENV‐3 genotypes and strains isolated at different time‐points during the 2000 and 2001–2002 Havana epidemics were included. A panel of 20 late convalescent sera collected 16–18 months after acute illness from DF and DHF patients are studied. These individuals were infected during the 2001–2002 Havana DENV‐3 epidemic. All but four sera collected from DF cases had a secondary DENV‐1/DENV‐3 infection. Sera neutralizing antibody titer against the seven DENV‐3 strains were determined by plaque reduction neutralization technique. Sera samples were tested simultaneously. Studied sera showed higher levels of neutralizing antibodies to DENV‐3 strains of genotype III compared to genotype V. Interesting, higher levels of neutralizing antibodies were detected to DENV‐3 strain isolated at the end of the epidemic 2001–2002. An increased tendency of GMT of neutralizing antibodies according to epidemic evolution was observed for the 2001–2002 outbreak. In general, antibody levels in sera collected from DF cases were higher. Differences in the neutralization capacity of immune DENV‐3 sera tested against two homologous genotypes including strains of the same genotype are demonstrated. Observed results suggest that virus changed in the course of the epidemic. The implications of this finding in terms of dengue pathogenesis and vaccine development need to be considered. J. Med. Virol. 80:1783–1789, 2008. © 2008 Wiley‐Liss, Inc.
The analysis of the entire HLA, partial non‐HLA and HPV for Chinese women with cervical cancer
Authors: Wu Yuping , Zhang Qinming , Liu Benrong , Yu Guifang
Published: August 2008

Human leukocyte antigen (HLA) alleles have been associated with an increased or decreased risk of developing cervical cancer through infection with oncogenic forms of the human papillomavirus (HPV). The aim of this study was to analyze the interactions between HPV and HLA, particularly of the entire HLA and partial non‐HLA regions, in invasive cervical cancers. The results showed the distribution of HPV genotypes among patients with cervical cancer in this group: the overall prevalence of HPV DNA was 91.3% (274/300). A total of 16 HPV genotypes, HPV16, 18, 58, 33, 81, 31, 68, 39, 67, 6, 11, 26, 52, 62, 66, and 70, were detected in patients with cervical cancer. Among the cervical cancer specimens, 68.7% were positive for HPV16. Genotyping was performed with 112 microsatellite markers spanning the entire HLA region and partial region of chromosome 6q15‐16.3. D6S2766 and D6S2764, which are located near to the region containing the HLA‐DPB genes, were negatively related with cervical cancer (OR for the D6S2766‐195 allele carriers = 0.50), and positively related with cervical cancer (OR for the D6S2764‐209 allele carriers = 2.44), respectively. Significant association was found for D6S1043 (allele 132) with HPV16‐positive cervical cancer (OR = 4.52). There was an increased risk for carriers of alleles 112 and 132 at the D6S1043 locus, in particular for homozygotes. The present findings indicate that the antigenic presentation of HPV‐derived peptides and non‐HLA regions may be involved in the pathogenesis of HPV‐associated cervical cancer. J. Med. Virol. 80:1808–1813, 2008. © 2008 Wiley‐Liss, Inc.
Case Report: Human herpesvirus 6 reactivation associated with colitis in a lung transplant recipient
Authors: Lamoth F. , Jayet P.Y. , Aubert J.D. , Rotman S. , Mottet C. , Sahli R. , Lautenschlager I. , Pascual M. , Meylan P.
Published: August 2008

Whereas human herpesvirus 6 (HHV‐6) reactivation is frequent in solid organ transplant recipients, symptomatic disease is rare. A case of colitis associated with HHV‐6B reactivation was observed in a lung transplant recipient. This case report suggests that symptomatic HHV‐6 infection may occur in the absence of detectable viremia. J. Med. Virol. 80:1804–1807, 2008. © 2008 Wiley‐Liss, Inc.
Serum thrombospondin‐1 is altered in patients with hemorrhagic fever with renal syndrome
Authors: Liu Zhengwen , Zhao Qianzi , Han Qunying , Gao Maicang , Zhang Ni
Published: August 2008

Hemorrhagic fever with renal syndrome (HFRS) is a severe acute viral disease with pathological changes of impaired capillary and small vessels and thrombocytopenia. In this study, serum thrombospondin (TSP)‐1 concentration in patients with HFRS was determined to explore its possible role in the pathogenesis of HFRS. The concentration of TSP‐1 was measured using a competitive enzyme‐linked immunoabsorbent assay. Significantly decreased levels of serum TSP‐1 were observed in HFRS patients at febrile and hypotensive phases compared with those in the controls. The serum levels of TSP‐1 in HFRS patients with more severe clinical types was reduced more profoundly than those in patients with milder clinical types at febrile and hypotensive phases, although the differences in TSP‐1 were not significant. It was indicated that insufficient production or increased consumption of TSP‐1, or both of these, may contribute to the impairment of capillary and small vessels and the development of hypotension at the early stage of HFRS, and the decreased degree may be associated with disease severity. J. Med. Virol. 80:1799–1803, 2008. © 2008 Wiley‐Liss, Inc.
Longitudinal observation of parechovirus in stool samples from Norwegian infants
Authors: Tapia German , Cinek Ondrej , Witsø Elisabet , Kulich Michal , Rasmussen Trond , Grinde Bjørn , Rønningen Kjersti S.
Published: August 2008

Parechoviruses are assumed to be common infectious agents, but their epidemiologic and pathogenic properties are not well known. The aim of the present study was to assess the prevalence and molecular epidemiology of Parechovirus in Norwegian infants, as well as to investigate whether the presence of virus correlated with symptoms of infection. A group of 102 infants was longitudinally followed: 51 infants with a high genetic risk for type 1 diabetes (aged 3–35 months), and 51 children without this genotype (aged 3–12). Stool samples were obtained each month, and symptoms of infection were recorded regularly on questionnaires. Human parechovirus was detected in 11.3% of 1,941 samples examined by real‐time RT‐PCR. There was a distinct seasonality, peaking from September to December. By 12 months of age, 43% of the infants had had at least one infection, while 86% of the infants had encountered the virus by the end of the second year. Based on the VP1 sequence, human parechovirus 1 was the most prevalent type (76%), followed by human parechovirus 3 (13%), human parechovirus 6 (9%), an unclassified human parechovirus (1%), and human parechovirus 2 (1%). Ljungan virus, a murine parechovirus, was examined with a separate real‐time RT‐PCR, but no virus was detected. There was no significant association between infections and the following symptoms: coughing, sneezing, fever, diarrhea or vomiting. In conclusion, human parechovirus infects frequently infants at an early age without causing disease. J. Med. Virol. 80:1835–1842, 2008. © 2008 Wiley‐Liss, Inc.
Acute respiratory infection and influenza‐like illness viral etiologies in Brazilian adults
Authors: Bellei Nancy , Carraro Emerson , Perosa Ana , Watanabe Aripuana , Arruda Eurico , Granato Celso
Published: August 2008

Influenza‐like illness (ILI) definitions have been used worldwide for influenza surveillance. These different case definitions can vary with regard to sensitivity and predictive values for laboratory confirmed influenza. The literature has indicated the inclusion of other viruses may be the cause of these variable results. The objective of the study was to evaluate ILI national sentinel criteria and viral etiologies in adults diagnosed with acute respiratory infection (ARI) and/or ILI from 2001 to 2003 in Sao Paulo, Brazil. Clinical and laboratory evaluations were observed from 420 adults and collected on a daily basis from outpatient care units at University Hospital. The ILI definition included: fever plus at least one respiratory symptom (cough and/or sore throat) and one constitutional symptom (headache, malaise, myalgia, sweat or chills, or fatigue). DFA and RT‐PCR for influenza, parainfluenza, respiratory syncytial virus, adenovirus, enterovirus, coronavirus, rhinovirus, and metapneumovirus were performed on nasal washes and 61.8% resulted positive. The respiratory viruses detected most often were influenza and rhinovirus. ILI was reported for 240/420 patients (57.1%), with influenza and rhinovirus etiologies accounting for 30.9% and 19.6%, respectively. Rhinovirus peak activity was concurrent with the influenza season. These findings highlight the implications of other viruses in ILI etiology and suggest that during the influenza season, this clinical overlap must be considered in the diagnosis and clinical management of patients. J. Med. Virol. 80:1824–1827, 2008. © 2008 Wiley‐Liss, Inc.
Establishment of an indicator cell line to quantify Bovine Foamy Virus infection
Authors: Ma Zhe , Hao Peng , Yao Xue , Liu Chang , Tan Juan , Liu Li , Yang Rongge , Geng Yunqi , Chen Qimin , Qiao Wentao
Published: August 2008

A cell line derived from baby hamster kidney (BHK‐21) cells was transfected with the enhanced green fluorescent protein gene driven by the bovine foamy virus (BFV) long terminal repeat (LTR) to establish a BFV indicator cell line (BICL). Among 48 clones, one clone was chosen for its little constitutive enhanced green fluorescent protein (EGFP) expression and high level of EGFP expression after activation by BFV infection. By detecting the EGFP expression of the BFV indicator cell line, the titers of BFV were quantified by the end point method. As a result, the titer determined by the EGFP based assay 5–6 days post infection (d.p.i.) was 100 fold higher than traditional assays measuring cytopathic effects 8–9 d.p.i.. Moreover, the EGFP based assay was also used to determine the titer of those cells infected by BFV without inducing cytopathic effects. Using this simple and rapid assay, we examined the in vitro host range of BFV. It was found that BFV can productively infect various cell lines derived from bovine, human, rat and monkey. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
1H17O nuclear quadrupole double resonance in phenylphosphinic acid and phenylphosphonic acid. 17O quadrupole coupling in P = O and POH bonds
Authors: Seliger J. , Žagar V.
Published: August 2008

The 17O nuclear quadrupole resonance (NQR) frequencies have been measured in phenylphosphinic acid and phenylphosphonic acid using nuclear quadrupole double resonance. The quadrupole coupling constants have been determined with an uncertainty of ± 10 kHz and the asymmetry parameter η with an uncertainty of ± 0.01. The results are compared to the published results of the theoretical calculation and the high‐field solid‐state NMR measurements. The position of hydrogen in the OH···O hydrogen bond in phenylphosphinic acid has also been determined. On the basis of the present and the previously published data we show that the principal values of the electric‐field‐gradient tensor in P  O and POH bonds correlate. A correlation between the nuclear quadrupole parameters and the length of the PO bond is also observed. Copyright © 2008 John Wiley & Sons, Ltd.
Education and drug use in Sweden—a nationwide register‐based study
Authors: Weitoft G. Ringbäck , Rosén M. , Ericsson Ö. , Ljung R.
Published: August 2008

Purpose

To analyse educational variations in prescriptions dispensed in Sweden. A better knowledge of the use of drugs in the population, including socioeconomic distribution, is a prerequisite in efforts to estimate whether drugs are being prescribed and used according to need. This knowledge may also facilitate the identification of selection or confounding factors when analysing outcome or adverse side effects of drug treatment.

Methods

All prescriptions dispensed during 2006 for 22 different categories of drugs were analysed in the Swedish Prescribed Drug Register. Each prescription was linked by a unique personal identification number (PIN) to the National Education Register. In total, analyses covered 1 557 740 men and 1 568 175 women aged 45–74.

Results

Those with low education were generally at higher risk of having drugs, odds ratios (ORs) varying from 1.2 to 2. Most differences appeared to be of the same magnitude as those found in studies of the relation between education and disease incidence and prevalence, that is drugs may be prescribed and dispensed according to need. However, there are some drugs, such as antibiotics, sildenafil, hormone replacement drugs, anti‐migraine drugs and angiotensin receptor blockers (ARB), where people with higher education have higher consumption than is expected from incidence and prevalence data.

Conclusions

There are rather large differences in drug utilization between groups of different educational levels. Mostly these disparities seem to reflect differences in need, but there are examples of inequalities in drug use. Copyright © 2008 John Wiley & Sons, Ltd.
Optical properties of CuCl films on silicon substrates
Authors: Mitra Anirban , O'Reilly L. , Lucas O. F. , Natarajan Gomathi , Danieluk D. , Bradley A. L. , McNally P. J. , Daniels S. , Cameron D. C. , Reader A. , Martinez‐Rosas M.
Published: August 2008

Semiconductor photonic emitters operating in the UV range remain an elusive goal. Attention has focused mainly on III‐Nitrides. However a large lattice constant difference between the III‐Nitride layers and compatible substrates results in high densities of misfit dislocations and consequently the device performance is adversely affected. An alternative novel material system, γ‐CuCl on silicon, is investigated. Properties of the exciton luminescence from vacuum deposited CuCl films on Si(100) and Si(111) are studied using temperature dependent photoluminescence (PL) spectroscopy. Four peaks attributed to the free exciton (Z3) (3.203 eV), bound exciton (I1) (3.181 eV), bi‐exciton (M) (3.159 eV) and bound bi‐exciton (N1) (3.134 eV) are identified from the PL spectrum at 10 K. A free exciton peak at 3.230 eV is observed at room temperature. The binding energies for the bound exciton, bi‐exciton and bound bi‐exciton are determined. Parameters, extracted from the temperature dependence of the Z3 PL peak intensity, energy and line‐width, have been compared with CuCl films on different substrates and in single crystal form. The luminescence properties of the CuCl on Si material system are found to compare well with reports for single crystal CuCl. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A detailed comparison of CVD grown and precursor based DWCNTs
Authors: Pfeiffer R. , Peterlik H. , Kuzmany H. , Simon F. , Pressl K. , Knoll P. , Rümmeli M. H. , Shiozawa H. , Muramatsu H. , Kim Y. A. , Hayashi T. , Endo M.
Published: August 2008

Double‐wall carbon nanotubes (DWCNTs) grown directly via a CVD method and DWCNTs produced by annealing C60and ferrocene filled single‐wall carbon nanotubes were studied with X‐ray diffraction (XRD) and Raman spectroscopy. The samples showed the typical XRD patterns of hexagonally bundled tubes. The frequencies and linewidths of the inner tube radial breathing modes (RBMs) were (with in experimental precision) equal in all three samples only the intensities differed. Finally, all samples showed the typical clustering of the inner tube RBMs due to the distribution of inner‐outer tube pairs. The only difference was the population of specific inner‐outer tube pairs where the CVD and ferrocene based DWCNTs were rather similar and both differed from the C60based DWCNTs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature‐dependent photoluminescence study of ErSc2N@C80 and Er2ScN@C80 fullerenes
Authors: Tiwari Archana , Dantelle Géraldine , Porfyrakis Kyriakos , Ardavan Arzhang , Briggs G. Andrew D.
Published: August 2008

The photoluminescence study of the Er3+ ion in ErSc2N@C80 and Er2ScN@C80 fullerenes in the temperature range of 5 K to 80 K is presented. New emission peaks are observed for both fullerenes above 20 K. These peaks arise from thermally populated crystal‐field levels of the excited state. An anomalous behaviour of the PL peak area is observed with an increasing temperature which reveals an internal rearrangement of the cluster ErSc2N in ErSc2N@C80. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Adhesion of osteoblasts on chemically patterned nanocrystalline diamonds
Authors: Kalbacova Marie , Michalikova Lenka , Baresova Veronika , Kromka Alexander , Rezek Bohuslav , Kmoch Stanislav
Published: August 2008

The compatibility of engineered surfaces with tissues, cells and biological molecules is critical in development of medical diagnostics, biosensors, drug delivery systems, etc. Nanocrystalline diamond (NCD) films represent group of novel materials with superior electro‐optical, chemical, and mechanical properties for such devices.

We studied adhesion and viability of human osteoblastic cells on NCD films with the aim to define optimal semiconductor interfaces for novel thin‐film biosensor. We cultured human osteoblasts (SAOS‐2) at different densities on chemically terminated NCD films with periodical O‐ and H‐terminated stripes of different width – 30, 100 and 200 µm and analysed cell cytoskeleton (actin filaments) and focal adhesions by fluorescence microscopy. We found that cell attachment is guided by the hydrophilic/hydrophobic patterns with preferential initial cellular adhesion on hydrophilic (O‐terminated) surface. Cell adhesion seems to be mediated by preferential culture medium proteins adsorption on the surface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid grid/particle filter for Lagrangian data assimilation. I: Formulating the passive scalar approximation
Authors: Salman H.
Published: August 2008

In this two‐part paper, we present a new nonlinear method for the assimilation of Lagrangian data. In part I, we formulate the method as a generalization of other particle filters. A particularly novel feature of the formulation is the use of a hybrid discretisation of the probability density function (PDF) in physical/phase space. Moreover, we show that, under the assumption that the drifters are uncorrelated, the projection of the Fokker–Planck equation onto the observation space associated with the drifter positions reduces to a set of passive scalar equations. This property allows us to efficiently compute the transitional PDF. To compute the analysis states, we present a grid/particle filter specifically formulated for use with the hybrid representation of our PDF. In common with other particle filters, our filter can suffer from sample impoverishment. To remedy this problem, we extend the Gaussian resampling procedure of Xionget al. to produce a very efficient filter. This produces a fully functional scheme for Lagrangian data assimilation when combined with our forecasts of the prior. Copyright © 2008 Royal Meteorological Society
Migratory fishes of Brazil: Life history and fish passage needs
Authors: Godinho Alexandre L. , Kynard Boyd
Published: August 2008

Many of the most important commercial and recreational species of the megadiverse Brazilian freshwater fishes migrate in rivers among essential habitats during all life stages. These movements, however, have been severely blocked by hundreds of hydroelectric dams and reservoirs and they will be even more obstructed due to hundreds of new developments. Fishways have been used in many countries to allow fish to pass around dams. Fishway construction is booming in Brazil, but poor understanding of migrations by Brazilian fishes has led legislators, scientists, and the public to several misconceptions about the rules of fishways in fisheries conservation. First, is a belief that fishways are only needed to facilitate upstream spawning migrations. Also, it has been suggested that upstream passage for Neotropical migrant fishes is not useful if there is no large free‐flowing stretch upstream of a dam that contains spawning habitat and has a large natural floodplain (nursery habitat). In this paper, we discuss that, in addition to providing passage for pre‐spawning migrants, upstream fishways also provide passage for other fish migrations (e.g. foraging), and that all up‐ and downstream migrations during life history need to be addressed at dams to conserve fish resources. We also argue that an upstream fishway is important even if the upstream reach does not have spawning or nursery habitats. In addition, we discuss the need for protection of downstream migrant fish, and the importance of fish behaviourists and engineers working together on fishway design and operation to solve fish passage issues. Copyright © 2008 John Wiley & Sons, Ltd.
XPS analysis of aluminum nitride films deposited by plasma source molecular beam epitaxy
Authors: Rosenberger Leland , Baird Ronald , McCullen Erik , Auner Gregory , Shreve Gina
Published: August 2008

Ten samples of crystalline aluminum nitride (AlN) film were deposited on sapphire and silicon substrates by a plasma source molecular beam method. The samples were analyzed using X‐ray photoelectron spectroscopy (XPS) depth profiling and high‐resolution X‐ray diffraction. Oxygen levels were observed to decrease exponentially from the surface into the bulk film. Aluminum, nitrogen and oxygen peaks were fitted with subpeaks in a consistent manner and the subpeaks were assigned to chemical states. AlN subpeaks were observed at 73.5 eV for Al2p and 396.4 eV for N1s. An N1s subpeak at 395.0 eV was assigned to NN defects. No direct NO bonds are assigned; rather it is proposed that an NAlO bond sequence is the source of higher binding energy N1s subpeaks. The observations in this study support a model in which oxygen is bound only to aluminum in the form of AlO octahedral complexes dispersed or clustered throughout the main AlN matrix or as AlO bonds on the crystal grain boundaries. The data also suggest that the AlN lattice parameters are related to oxygen content, since the c‐axis is observed to increase with increasing oxygen content. Copyright © 2008 John Wiley & Sons, Ltd.
Altered hippocampal expression of glutamate receptors and transporters in GRM2 and GRM3 knockout mice
Authors: Lyon Louisa , Kew James N.C. , Corti Corrado , Harrison Paul J. , Burnet Philip W.J.
Published: August 2008

Group II metabotropic glutamate receptors (mGluR2 and mGluR3, also called mGlu2 and mGlu3, encoded byGRM2andGRM3, respectively) are therapeutic targets for several psychiatric disorders.GRM3may also be a schizophrenia susceptibility gene. mGluR2−/−and mGluR3−/−mice provide the only unequivocal means to differentiate between these receptors, yet interpretation of in vivo findings may be complicated by secondary effects on expression of other genes. To address this issue, we examined the expression of NMDA receptor subunits (NR1, NR2A, NR2B) and glutamate transporters (EAAT1‐3), as well as the remaining group II mGluR, in the hippocampus of mGluR2−/−and mGluR3−/−mice, compared with wild‐type controls. mGluR2 mRNA was increased in mGluR3−/−mice, and vice versa. NR2A mRNA was increased in both knockout mice. EAAT1 (GLAST) mRNA and protein, and EAAT2 (GLT‐1) protein, were reduced in mGluR3−/−mice, whereas EAAT3 (EAAC1) mRNA was decreased in mGluR2−/−mice. Transcripts for NR1 and NR2B were unchanged. The findings show a compensatory upregulation of the remaining group II metabotropic glutamate receptor in the knockout mice. Upregulation of NR2A expression suggests modified NMDA receptor signaling in mGluR2−/−and mGluR3−/−mice, and downregulation of glutamate transporter expression suggests a response to altered synaptic glutamate levels. The results show a mutual interplay between mGluR2 and mGluR3, and also provide a context in which to interpret behavioral and electrophysiological results in these mice. Synapse 62:842–850, 2008. © 2008 Wiley‐Liss, Inc.
Living with Long QT Syndrome: A Qualitative Study of Coping with Increased Risk of Sudden Cardiac Death
Authors: Andersen Janice , Øyen Nina , Bjorvatn Cathrine , Gjengedal Eva
Published: August 2008

Long QT syndrome (LQTS) is a congenital disorder associated with increased risk of sudden cardiac death; LQTS patients and their families are offered diagnostic or predictive genetic testing. The purpose of this qualitative study was to investigate the psychosocial aspects of living with LQTS, to identify LQTS patients’ daily life challenges and coping strategies, and to describe their experiences with healthcare services. In‐depth interviews were conducted with seven individuals who had been tested for long QT genetic mutation. Four of these participants had an implantable cardiac defibrillator (ICD). The participants reported that early and gradually acquired knowledge of the syndrome was an advantage. They also reported experiencing worries and limitations in daily life, but their main concern was for their children or grandchildren. Healthcare providers’ minimal knowledge of LQTS resulted in uncertainty, misinformation, and even wrong advice regarding treatment. The results suggest that regional centers, with the appropriate expertise, should investigate and counsel LQTS patients and their families.
Interaction Between an Anionic and an Amphoteric Surfactant. Part I: Monomer–Micelle Equilibrium
Authors: Soontravanich Sukhwan , Munoz Joline A. , Scamehorn John F. , Harwell Jeffrey H. , Sabatini David A.
Published: August 2008

A mixture of anionic and amphoteric surfactants is composed of three components at intermediate pH levels: anionic, cationic (protonated amphoteric), and zwitterionic (unprotonated amphoteric). Knowledge of the composition of each surfactant in both monomer and micellar forms (monomer–micelle equilibrium) is important in applications using this mixture. Hydrogen ion titration of the mixed surfactant solution as a function of surfactant composition is combined with the pseudophase separation model and regular solution theory for the three‐surfactant mixture to calculate the concentration of each surfactant in monomer and in micelle forms at different pH levels. The specific systems studied here contain sodium dodecyl sulfate (SDS) and dimethyldodecylamine oxide (DDAO), which are used in a wide range of consumer products. The degree of protonation of monomeric DDAO is not affected by the presence of SDS, indicating an insignificant formation of ion pairs between these monomers. However, the presence of SDS in micelles shifts the micellar pKa of DDAO protonation significantly and the method used here allows the quantification of partial fugacities of each individual surfactant in micelle form. The composition in the monomer phase at each pH will aid in understanding and predicting solution compositions corresponding to anionic/amphoteric surfactant precipitation boundaries, which is the focus of the subsequent paper in this series.
The evolution of the intellectual structure of operations management—1980–2006: A citation/co‐citation analysis
Authors: Pilkington Alan , Meredith Jack
Published: August 2008

Citation analysis combined with a network analysis of co‐citation data from three major operations management (OM) journals is used to reveal the evolution of the intellectual structure of the OM field between 1980 and 2006. This spans the entire time since the beginning of research journals specific to the field. Employing a bibliometric citation/co‐citation analysis to investigate the foundations of the discipline enables a robust, quantitative approach to uncovering the evolution of research in OM. The study finds that the intellectual structure of the field made statistically significant changes between the 1980s, the 1990s, and the 2000s and evolved from a pre‐occupation with narrow, tactical topics toward more strategic, macrotopics, including new research methods and techniques. A factor analysis identifies the 12 top knowledge groups in the field and how they change over the decades. Illustrations of the structure of the co‐citations representing the field are generated from a spring‐embedded algorithm that is an improvement over the standard multi‐dimensional scaling (MDS) approach to illustrating the knowledge groups.
An overview of mobile assisted language learning: From content delivery to supported collaboration and interaction
Authors: Kukulska-Hulme Agnes , Shield Lesley
Published: August 2008

Mobile learning is undergoing rapid evolution. While early generations of mobile learning tended to propose activities that were carefully crafted by educators and technologists, learners are increasingly motivated by their personal learning needs, including those arising from greater mobility and frequent travel. At the same time, it is often argued that mobile devices are particularly suited to supporting social contacts and collaborative learning - claims that have obvious relevance for language learning. A review of publications reporting mobile-assisted language learning (MALL) was undertaken to discover how far mobile devices are being used to support social contact and collaborative learning. In particular, we were interested in speaking and listening practice and in the possibilities for both synchronous and asynchronous interaction in the context of online and distance learning. We reflect on how mobile language learning has developed to date and suggest directions for the future.
Germination of Viburnum odoratissimum seeds: a new level of morphophysiological dormancy
Authors: Baskin Carol C. , Chien Ching-Te , Chen Shun-Ying , Baskin Jerry M.
Published: August 2008

Previous studies indicated that seeds of Viburnum odoratissimum had only physiological dormancy (PD), but no measurements of embryos were made during the dormancy-break treatments. Thus, we investigated embryo growth and radicle and cotyledon emergence over a range of temperatures. Seeds have underdeveloped embryos, and their length increased about 300% before radicle emergence. Embryos also had PD, as evidenced by delays in beginning of embryo growth (2–3 weeks) and of germination after embryos were elongated (4 weeks). After radicle emergence, epicotyl emergence was delayed 1–8 weeks, depending on incubation temperature, but cold stratification was not required to break PD of the epicotyl. Unlike seeds of many previously studied Viburnum spp., epicotyls of V. odoratissimum have non-deep, rather than deep, PD. Hence, a new level of MPD called non-deep, simple, epicotyl MPD has been identified.
Tidal variations of flow convergence, shear, and stratification at the Rio de la Plata estuary turbidity front
Authors: Framiñan Mariana B. , Valle‐Levinson Arnoldo , Sepúlveda Héctor H. , Brown Otis B.
Published: August 2008

Intratidal variability of density and velocity fields is investigated at the turbidity front of the Río de la Plata Estuary, South America. Current velocity and temperature‐salinity profiles collected in August 1999 along a repeated transect crossing the front are analyzed. Horizontal and vertical gradients, stability of the front, convergence zones, and transverse flow associated to the frontal boundary are described. Strong horizontal convergence of the across‐front velocity and build up of along‐front velocity shear were observed at the front. In the proximity of the front, enhanced transverse (or along‐front) flow created jet‐like structures at the surface and near the bottom flowing in opposite directions. These structures persisted throughout the tidal cycle and were advected upstream (downstream) by the flood (ebb) current through a distance of ∼10 km. During peak flood, the upper layer flow reversed from its predominant downstream direction and upstreamflow occupied the entire water column; outside the peak flood, two‐layer estuarine circulation dominated. Changes in density field were observed in response to tidal straining, tidal advection, and wind‐induced mixing, but stratification remained throughout the tidal cycle. This work demonstrates the large spatial variability of the velocity field at the turbidity front; it provides evidence of enhanced transverse circulation along the frontal boundary; and reveals the importance of advective and frictional intratidal processes in the dynamics of the central part of the estuary.
Impact of a tropical cyclone on biogeochemistry of the central Arabian Sea
Authors: Naik Hema , Naqvi S. W. A. , Suresh T. , Narvekar P. V.
Published: August 2008

Remotely sensed data are combined with shipboard measurements to investigate biogeochemical changes caused by a moderate tropical cyclone in the central Arabian Sea in December 1998. The sea surface temperature decreased by ∼4°C, whereas surface nitrate and chlorophyll concentrations increased by >5 μM and up to 4 mg m−3, respectively, over a large area affected by the cyclone. Nutrient enrichment in the surface layer of the cyclone‐affected zone is estimated to have supported a new production of ∼4.2 Tg C, approximately 5% of the annual organic carbon export to the deep sea (beyond the continental margin) for the entire Arabian Sea. Entrainment of nitrous oxide from the thermocline led to more than doubling of its concentration in the mixed layer. The cyclone also resulted in an increase in nitrous oxide inventory within the oxygen minimum zone. Our results imply that, should there be an increase in the frequency and intensity of tropical cyclones as a result of global warming, as projected in some recent reports, carbon production and respiration, and redox processes within the oxygen minimum zones, such as the production of nitrous oxide through nitrification/denitrification, and of molecular nitrogen through denitrification/anaerobic ammonium oxidation, may be significantly impacted.
A reconstruction of global agricultural areas and land cover for the last millennium
Authors: Pongratz J. , Reick C. , Raddatz T. , Claussen M.
Published: August 2008

Humans have substantially modified the Earth's land cover, especially by transforming natural ecosystems to agricultural areas. In preindustrial times, the expansion of agriculture was probably the dominant process by which humankind altered the Earth system, but little is known about its extent, timing, and spatial pattern. This study presents an approach to reconstruct spatially explicit changes in global agricultural areas (cropland and pasture) and the resulting changes in land cover over the last millennium. The reconstruction is based on published maps of agricultural areas for the last three centuries. For earlier times, a country‐based method is developed that uses population data as a proxy for agricultural activity. With this approach, the extent of cropland and pasture is consistently estimated since AD 800. The resulting reconstruction of agricultural areas is combined with a map of potential vegetation to estimate the resulting historical changes in land cover. Uncertainties associated with this approach, in particular owing to technological progress in agriculture and uncertainties in population estimates, are quantified. About 5 million km2 of natural vegetation are found to be transformed to agriculture between AD 800 and 1700, slightly more to cropland (mainly at the expense of forested area) than to pasture (mainly at the expense of natural grasslands). Historical events such as the Black Death in Europe led to considerable dynamics in land cover change on a regional scale. The reconstruction can be used with global climate and ecosystem models to assess the impact of human activities on the Earth system in preindustrial times.
Zonal flow generation by internal gravity waves in the atmosphere
Authors: Horton W. , Kaladze T. D. , Van Dam J. W. , Garner T. W.
Published: August 2008

A novel mechanism for the generation of low‐frequency large‐scale zonal flows by higher‐frequency, small‐scale, finite‐amplitude internal gravity (IG) waves is analyzed in the atmosphere from the troposphere to the ionosphere E layer. The nonlinear generation mechanism is based on the parametric excitation of convective cells by finite‐amplitude IG waves. A set of coupled equations describing the nonlinear interaction of IG waves and zonal flows is derived. The generation of zonal flows is due to the Reynolds stress and mean stratification forces produced by finite‐amplitude IG waves. The onset mechanism for the instability is governed by a generalized Lighthill instability criterion. Explicit expressions for the maximum growth rate as well as for the optimal spatial dimensions of the zonal flows are derived. The growth rates of zonal flow instabilities and the conditions for driving them are determined. A comparison with existing results is carried out. The present theory can be used for the interpretation of IG wave observations in the Earth's atmosphere and laboratory experiments. Some earthquake‐related phenomena are briefly discussed.