bluuebunny/crossref_metadata_2025 huggingface dataset:
Subfunctionalization of a Retinoid-Binding Protein Provides Evidence for Two Parallel Visual Cycles in the Cone-Dominant Zebrafish Retina
Authors: Fleisch Valerie C. , Schonthaler Helia B. , von Lintig Johannes , Neuhauss Stephan C. F.
Published: August 2008

In vertebrates, the absorption of a photon results in an 11-cisto all-transisomerization of the retinylidene chromophore of cone and rod visual pigments. To sustain vision, metabolic pathways (visual cycles) have evolved that recycle all-trans-retinal back to 11-cis-retinal. The canonical visual cycle takes place in photoreceptor cells and the adjacent retinal pigment epithelium (RPE). Biochemical analyses provided evidence for the existence of an additional cone-specific visual cycle involving Müller glia cells, but none of its molecular components has yet been identified. Here we took advantage of the zebrafish retina to investigate the role of the cellular retinaldehyde-binding protein CRALBP in this process. We found that the zebrafish genome encodes twocralbpparalogs:cralbp aandcralbp b. These paralogs are differentially expressed in the retina. Cralbp a is exclusively expressed in the RPE, and Cralbp b is localized to Müller cells. We used an antisense morpholino approach to knock down eachcralbpparalog. Analysis of 11-cis-retinal levels revealed that visual chromophore regeneration is diminished under both conditions. Visual performance, as assessed by electroretinography, revealed reduced light sensitivity in both Cralbp a- and Cralbp b-deficient larvae, but it was more pronounced in Cralbp b-deficient larvae. Cralbp b-deficient larvae also exhibited significant deficits in their visual behavior. Together, these data demonstrate that Cralbp expression in Müller cells is essential for cone vision, thereby providing evidence that both the canonical and the alternative visual cycle depend on the same type of retinoid-binding protein.
Efficient Recruitment of Layer 2/3 Interneurons by Layer 4 Input in Single Columns of Rat Somatosensory Cortex
Authors: Helmstaedter Moritz , Staiger Jochen F. , Sakmann Bert , Feldmeyer Dirk
Published: August 2008

Interneurons in layers 2/3 are excited by pyramidal cells within the same layer (Reyes et al., 1998; Gupta et al., 2000), but little is known about translaminar innervation of these interneurons by spiny neurons in the main cortical input layer 4 (L4). Here, we investigated (1) how efficiently L4 spiny neurons excite L2/3 interneurons via monosynaptic connections, (2) whether glutamate release from axon terminals of L4 spiny neurons depends on the identity of the postsynaptic interneuron, and (3) how L4-to-L2/3 interneuron connections compare with L4-to-L2/3 pyramidal neuron connections. We recorded from pairs of L4 spiny neurons and L2/3 interneurons in acute slices of rat barrel cortex of postnatal day 20 (P20) to P29 rats. The L4-to-L2/3 interneuron connections had an average unitary EPSP of 1.2 ± 1.1 mV. We found an average of 2.3 ± 0.8 contacts per connection, and the L4-to-L2/3 interneuron innervation domains were mostly column restricted. Unitary EPSP amplitudes and paired-pulse ratios in the L4-to-L2/3 interneuron connections depended on the “group” of the postsynaptic interneuron. Averaged over all L4-to-L2/3 interneuron connections, unitary EPSP amplitudes were 1.8-fold higher than in the translaminar L4-to-L2/3 pyramidal cell connections. Our results suggest that L4 spiny neurons may more efficiently recruit L2/3 interneurons than L2/3 pyramidal neurons, and that glutamate release from translaminar boutons of L4 spiny neuron axons is target cell specific.
The capability of plasma osteoprotegerin as a predictor of cardiovascular disease: a systematic literature review
Authors: Nybo Mads , Rasmussen Lars M
Published: August 2008

Objective

Osteoprotegerin (OPG) strongly inhibits bone resorption and may also serve as a vascular calcification inhibitor. However, recent studies have indicated that high plasma OPG is a strong predictor of cardiovascular disease (CVD) and mortality. To evaluate this capability, the data concerning OPG as a CVD predictor was gathered through a systematic literature review.

Design and methods

Studies investigating OPG as a predictor of CVD or mortality were extracted from Medline and the Cochrane Library, retrieving 187 articles. Non-relevant articles were excluded, resulting in a total of 45 articles. After thorough evaluation of the abstracts, only eight prospective studies containing a follow-up period with a clinical emphasis on CVD were eligible for the literature review.

Results

All studies except one confirmed that OPG measurement adds important prognostic information to the existing markers of CVD and mortality in high-risk populations. Hazard ratios emphasized the significant correlation between plasma OPG concentration and mortality. Due to methodological problems (e.g., population investigated, measurement principle, and statistics performed), meta-analysis could not be performed. As only one study was conducted in a healthy cohort, the results cannot per se be extrapolated to the general population.

Conclusion

The combined results support plasma OPG as an independent predictor of CVD and mortality in high-risk populations. However, more longitudinal studies in general cohorts are needed before the use of plasma OPG can be evaluated in this regard.
Hepatocyte nuclear factor 1 binding element within the promoter of microsomal triglyceride transfer protein (MTTP) gene is crucial for MTTP basal expression and insulin responsiveness
Authors: Au Wo-Shing , Lu Liwei , Yeung Chung-Man , Liu Ching-Chiu , Wong Oscar G , Lai Lihui , Kung Hsiang-fu , Lin Marie C
Published: August 2008

Insulin inhibits the transcription of the microsomal triglyceride transfer protein (MTTP), which plays a pivotal role in lipoprotein assembly and secretion. Here, we provide evidence that a hepatocyte nuclear factor 1 binding element (HNF1A element) within the MTTP promoter serves as a novel negative insulin-responsive element. Deletion/mutation mapping of the MTTP gene promoter identified a modified HNF1A element that is crucial to the negative insulin effect. Chimeric promoter containing this HNF1A element and minimal TEAD1 promoter also responded negatively toward insulin treatment. Gel shift assay demonstrated that HNF1A but not HNF1B binds to this element. Enforced expression of HNF1A was sufficient to reconstitute the negative insulin responsiveness of MTTP promoter in TM4SF1 myocytes that are HNF1A negative. Furthermore, replacing this element with consensus HNF1A element preserved the negative insulin response, suggesting that negative insulin responsiveness is a generic characteristic of HNF1A element. Given that many genes implicated in diabetes contain HNF1A element, the potential regulation of these genes by insulin via HNF1A element may provide important clues for the manifestation and treatment of diabetic metabolic syndromes.
Affinity properties of truss model nodes
Authors: Clyde D.
Published: August 2008

In the application of lower bound theory to reinforced concrete beams, strut and tie models are trusses that consist of axial force members, which react on one another and on external supports through nodes. In a line diagram of struts and ties, they intersect in points, which ensure that moment equilibrium is satisfied at the nodes. The paper examines the implications of replacing the line diagram with members that are of full width – that is compression members at compression yield and anchorages for tension members which act on concrete at compression yield. The nodes will be in hydrostatic compression; for nodes where more than three forces meet, however, the resulting detail becomes unnecessarily complicated. The paper demonstrates that if such a node is chosen as a shape which is affine to the vector diagram of the forces that act on it, the forces will not be concurrent but moment equilibrium will nonetheless be satisfied. Although the general multimember node would be unstable, in the practical case of the support point of a simply supported beam, the constraints of the location of external reactions and of the reinforcement detailing are shown to reduce the analysis of the node to a determinate problem.
MALTHUSIAN OVERFISHING AND EFFORTS TO OVERCOME IT ON KENYAN CORAL REEFS
Authors: McClanahan Tim R. , Hicks Christina C. , Darling Emily S.
Published: August 2008

This study examined trends along a gradient of fishing intensity in an artisanal coral reef fishery over a 10‐year period along 75 km of Kenya's most populated coastline. As predicted by Malthusian scenarios, catch per unit effort (CPUE), mean trophic level, the functional diversity of fished taxa, and the diversity of gear declined, while total annual catch and catch variability increased along the fishing pressure gradient. The fishery was able to sustain high (∼16 Mg·km−2·yr−1) but variable yields at high fishing pressure due to the dominance of a few productive herbivorous fish species in the catch. The effect of two separate management strategies to overcome this Malthusian pattern was investigated: fisheries area closure and elimination of the dominant and most “competitive” gear. We found that sites within 5 km of the enforced closure showed significantly lower total catch and CPUE, but increased yield stability and trophic level of catch than predicted by regression models normalized for fishing effort. Sites that had excluded illegal beach seine use through active gear management exhibited increased total catch and CPUE. There was a strong interaction between closure and gear management, which indicates that, for closures to be effective at increasing catch, there must be simultaneous efforts at gear management around the periphery of the closures. We propose that Malthusian effects are responsible for the variation in gear and catch and that active management through reduced effort and reductions in the most competitive gear have the greatest potential to increase the functional and trophic diversity and per‐person productivity.
OPTIMAL ANNUAL ROUTINES: NEW TOOLS FOR CONSERVATION BIOLOGY
Authors: Feró Orsolya , Stephens Philip A. , Barta Zoltán , McNamara John M. , Houston Alasdair I.
Published: August 2008

Many applied problems in ecology and conservation require prediction, and population models are important tools for that purpose. Formerly, the majority of predictive population models were based on matrix models. As the limitations of classical matrix models have become clearer, the use of individual‐based models has increased. These models use behavioral rules imposed at the level of the individual to establish the emergent consequences of those rules at the population level. Individual behaviors in such models use an array of different rule types, from empirically derived probabilities to long‐term fitness considerations. There has been surprisingly little discussion of the strengths and weaknesses of these different rule types. Here, we consider different strategies for modeling individual behaviors, together with some problems associated with individual‐based models. We propose a novel approach based on modeling optimal annual routines. Annual routines allow individual behaviors to be predicted over a whole annual cycle within the context of long‐term fitness considerations. Temporal trade‐offs between different behaviors are automatically included in annual routine models, overcoming some of the primary limitations of other individual‐based models. Furthermore, as well as population predictions, individual behaviors and indices of condition are emergent features of annual routine models. We show that these can be more sensitive to environmental change than population size, offering alternative, repeatable metrics for monitoring population status. Annual routine models provide no panacea for the problems of data limitations in predictive population modeling. However, as a result of their ability to deal with life‐history trade‐offs, as well as their potential for relatively rapid and accurate validation and parameterization, we suggest that annual routine models have strong potential for predictive population modeling in applied conservation settings.
WEED‐BIOCONTROL INSECTS REDUCE NATIVE‐PLANT RECRUITMENT THROUGH SECOND‐ORDER APPARENT COMPETITION
Authors: Pearson Dean E. , Callaway Ragan M.
Published: August 2008

Small‐mammal seed predation is an important force structuring native‐plant communities that may also influence exotic‐plant invasions. In the intermountain West, deer mice (Peromyscus maniculatus) are prominent predators of native‐plant seeds, but they avoid consuming seeds of certain widespread invasives like spotted knapweed (Centaurea maculosa). These mice also consume the biological‐control insects Urophora spp. introduced to control C. maculosa, and this food resource substantially increases deer mouse populations. Thus, mice may play an important role in the invasion and management of C. maculosa through food‐web interactions. We examined deer mouse seed predation and its effects on seedling emergence and establishment of a dominant native grass, Pseudoroegneria spicata, and forb, Balsamorhiza sagittata, in C. maculosa‐invaded grasslands that were treated with herbicide to suppress C. maculosa or left untreated as controls. Deer mice readily took seeds of both native plants but removed 2–20 times more of the larger B. sagittata seeds than the smaller P. spicata seeds. Seed predation reduced emergence and establishment of both species but had greater impacts on B. sagittata. The intensity of seed predation corresponded with annual and seasonal changes in deer mouse abundance, suggesting that abundance largely determined mouse impacts on native‐plant seeds. Accordingly, herbicide treatments that reduced mouse abundance by suppressing C. maculosa and its associated biocontrol food subsidies to mice also reduced seed predation and decreased the impact of deer mice on B. sagittata establishment. These results provide evidence that Urophora biocontrol agents may exacerbate the negative effects of C. maculosa on native plants through a form of second‐order apparent competition—a biocontrol indirect effect that has not been previously documented. Herbicide suppressed C. maculosa and Urophora, reducing mouse populations and moderating seed predation on native plants, but the herbicide's direct negative effects on native forb seedlings overwhelmed the indirect positive effect of reducing deer mouse seed predation. By manipulating this four‐level food chain, we illustrate that host‐specific biological control agents may impact nontarget plant species through food‐web interactions, and herbicides may influence management outcomes through indirect trophic interactions in addition to their direct effects on plants.
The effect of moisture content and alkalinity on the anaerobic biodegradation of VIP contents
Authors: Couderc A. A.-L. , Buckley C. A. , Foxon K. , Nwaneri C. F. , Bakare B. F. , Gounden T. , Battimelli A.
Published: August 2008

This study investigated the effect of additional moisture and/or alkalinity on the rate of anaerobic digestion in samples of material obtained from pit latrines. In modified serum bottle tests it was shown that poor gas production rates were observed from all experiments with material collected at the lower part of one pit. Using material from the top layer of a second pit it was shown that experimental bottles produced significant amounts of gas with both the addition of water and the addition of alkalinity. The results supports the motivating hypotheses that moisture content and pH buffering capacity obtained in VIP material are low and may be limiting factors in the rate of stabilisation that may occur in these pits. This implies that increasing the moisture content and alkalinity in the pit has the potential to increase stabilisation rate in the pit when the material is not already well-stabilised.
Acetate-fed aerobic granular sludge for the degradation of chlorinated phenols
Authors: Carucci A. , Milia S. , De Gioannis G. , Piredda M.
Published: August 2008

In this study, the possibility to use acetate-fed aerobic granular sludge for the degradation of low chlorinated 4-mono-chlorophenol (4CP) and highly chlorinated 2,4,6-tri- chlorophenol (TCP) was investigated. A Granulated Sequencing Batch Reactor (GSBR) was used to carry out the experiments, with acetate as growth substrate. 4CP concentration in the influent ranged between 0 and 50 mg/l, while TCP concentration varied between 0 and 15 mg/l. Different operating conditions were applied in order to obtain the complete aerobic degradation of 4CP. For TCP degradation, anaerobic feeding and control of dissolved oxygen concentration in the bulk liquid were used to keep the granules core under anaerobic conditions due to diffusion limitations: the possibility to obtain TCP reductive dechlorination under aerated conditions was thus investigated. Differences in granules shape and size were observed with 4CP and TCP dosed in the influent, and the effects of such toxic compounds on acetate removal were evaluated.

Aerobic granules grown on acetate as carbon source proved to be an interesting solution for the degradation of 4CP, showing good resistance to high 4CP concentrations in the influent even if unacclimated. The presence of TCP did not irreversibly inhibit biomass activity, and complete TCP degradation was achieved after acclimation.
Operation for nitritation of sludge liquor in a full-scale SBR
Authors: Gustavsson D. J. I. , Nyberg U. , Jansen J. la Cour
Published: August 2008

At Sjölunda WWTP, a full-scale SBR for treatment of mesophilic sludge digester liquor has been operated almost a year with stable nitrite accumulation. Only nitritation of the sludge liquor is needed since the oxidized ammonium is denitrified in the first anoxic zone of the high-loaded activated sludge in the main plant. The process strategy was to have an ammonium set-point to end the aeration, a low DO concentration and a low pH set-point. An increase of pH set-point from 6.8 to 7.2 increased loss of alkalinity in the effluent and increased sodium hydroxide dosing. An increase of DO set-point from 1.1 mg O2 L−1 to 1.3 mg O2 L−1 markedly increased ammonia reduction rates and only slightly increased nitrate production. Today, an introduction of denitritation in the SBR will be a more cost-effective treatment of sludge liquor at Sjölunda WWTP. However, the choice of operation with only nitritation or nitritation/denitritation in sludge liquor treatment should always include a consideration of chemical costs and treatment capacity of both main plant and side-stream plant.
Polishing of pretreated dye wastewater using novel sequencing batch reactors
Authors: Singh K. S. , LeBlanc M. M. , Bhattacharyya D.
Published: August 2008

Novel, aerobic sequencing batch reactor technology was tested as a polishing step for anaerobically treated textile wastewater containing dye. Operation cycle times of 6, 8 and 12 hours were studied using discrete phase periods. The SBRs were able to further remove influent dye concentration of as little as 5 mg/L, and remove highly variable loadings of COD and SS to effluent levels of 100 and 20 mg/L respectively.
Ozone oxidation of oestrogenic active substances in wastewater and drinking water
Authors: Baig S. , Hansmann G. , Paolini B.
Published: August 2008

Ozone oxidation is proven to be an effective solution for the degradation of selected oestrogenic active substances detected in secondary wastewaters such as β-oestradiol, oestrone, oestriol, 17-α-ethinyloestradiol, mestranol, daidzeine, β-sitosterol, bisphenol A, norethisterone, 4-tert-octylphenol and 4-iso-nonylphenol, up to their limit of detection. The matrix-effect of wastewater was investigated performing ozone experiments under batch mode and continuous mode using drinking water and a wastewater issued from a local plant both spiked with the non-detected substances. The results obtained indicate that the wastewater matrix greatly affects the kinetics of ozone reaction with these substances but does not really change the related reactivity scale. The ozone dose corresponding to the full conversion of target EDCs consequently increases as their oxidation takes place competing with reactions of background pollutants represented by the COD and DOC content. However, a usual dose close to 12 mg/L was found sufficient to provide high degradation yields for all substances studied while 35% of COD was removed. This is a contribution to the numerous current works focused on technologies able to improve the quality of water discharged from wastewater treatment plants, both considering conventional parameters and emerging contaminants.
Social and Cultural Capital, Race and Ethnicity, and College Student Retention
Authors: Wells Ryan
Published: August 2008

This study addresses the role that social and cultural capital play in first-to-second year persistence in higher education and examines how race and ethnicity are associated with initial levels of such capital. Using logistic regression analysis, the results show that social and cultural capital are positively significant for persistence in higher education across all racial and ethnic groups. However, results also show that certain groups, especially Hispanics, have lower levels of normatively valued forms of social and cultural capital than others. The effects for social and educational stratification are discussed, as are implications for higher education retention policies and further research.
Patterns of Doctoral Student Degree Completion: A Longitudinal Analysis
Authors: Most David E.
Published: August 2008

Despite decades of interest in Ph.D. student outcomes, there have been few comprehensive studies of doctoral student completion. Compared to research on undergraduate students, longitudinal studies of doctoral student completion in multiple disciplines at multiple institutions are exceptionally rare. As a consequence, there is relatively scant evidence to support general assertions regarding estimates and the temporal dimensions of completion rates. This study estimated and compared completion rates over time for 5,323 Ph.D. students from five fields in 16 institutions by field, gender, ethnicity, and prior Master's degree at entry status using the longitudinal database of the AAU/AGS Project for Research on Doctoral Education. Comparisons of the results with conventional wisdom and prior studies are offered. The findings can potentially inform the development of interventions and policy directed toward achieving desirable completion rates.
Students' Intentions and Social Support as Predictors of Self-Reported Academic Behaviors: A Comparison of First- and Continuing-Generation College Students
Authors: Purswell Katherine E. , Yazedjian Ani , Toews Michelle L.
Published: August 2008

The purpose of this analysis was to examine academic intentions, parental support, and peer support as predictors of self-reported academic behaviors among a sample of 329 first- and continuing-generation college freshmen. Regression analyses revealed that different variables predicted academic behaviors for the three groups examined (students whose parents had no college experience, some college experience, or a college degree). Specifically, all three independent variables—intention, parental support, and peer support—were predictive of self-reported academic behavior for students whose parents had at least a bachelor's degree. However, peer support was the only variable predictive of academic behavior for the students whose parents had some college experience and intention was the only significant predictor for first-generation college students.
The Utilization of Retention Strategies at Church-Related Colleges: A Longitudinal Study
Authors: Vander Schee Brian Anthony
Published: August 2008

Implementing effective student retention strategies is important for all institutions of higher education. This is especially true for smaller, private colleges as resources for higher education are stretched and the dependence on tuition revenue to maintain fiscal viability increases. This longitudinal study focuses on the utilization of retention strategies at Council for Christian Colleges and Universities member institutions. The results indicate that institutional selectivity and the utilization of a student retention program over a long period, as opposed to the utilization of any individual student retention strategy in particular, positively correlate with student retention to graduation. Conducting an annual evaluation of the effectiveness of enrollment management also showed statistically significant results. Implications for student retention at private colleges are discussed and considerations for future research are also highlighted.
Persistence and Attrition: What is Being Measured?
Authors: Park C. L. , Boman J. , Care W. Dean , Edwards M. , Perry B.
Published: August 2008

The purpose of this article is to discuss four assumptions commonly held in relation to persistence and or attrition rates at institutions of post secondary education: that persistence is positive, that persistence is an indicator of a program's ability to satisfy student need, that persistence is lower in distance education programs and that comparisons of persistence rates have meaning. The assumptions are explored in relation to the literature and to the data generated by the first complete cohort of graduate students in the Centre for Nursing and Health Studies at Athabasca University. We further propose formulae to address both persistence and attrition in online educational programs and present the variations in rates that can be produced.
Pregnancy Insulin, Glucose, and BMI Contribute to Birth Outcomes in Nondiabetic Mothers
Authors: Ong Ken K. , Diderholm Barbro , Salzano Giuseppina , Wingate Dianne , Hughes Ieuan A. , MacDougall Jane , Acerini Carlo L. , Dunger David B.
Published: August 2008

OBJECTIVE—We investigated the effects of normal variations in maternal glycemia on birth size and other birth outcomes.

RESEARCH DESIGN AND METHODS—Women in two unselected birth cohorts, one retrospective (n = 3,158) and one prospective (n = 668), underwent an oral glucose challenge at 28 weeks of gestation. In the retrospective study, glycemia was linked to routine birth records. In the prospective study, offspring adiposity was assessed by skinfold thickness from birth to age 24 months.

RESULTS—In the retrospective study, within the nondiabetic range (2.1–7.8 mmol/l), each 1 mmol/l rise in the mother's 60-min glucose level was associated with a (mean ± SEM) 2.1 ± 0.8% (P = 0.006) rise in absolute risk of assisted vaginal delivery, a 3.4 ± 0.8% (P < 0.0001) rise in emergency cesarean delivery, a 3.1 ± 0.7% (P < 0.0001) rise in elective cesarean delivery, and a 46 ± 8 g (P < 0.0001) increase in offspring birth weight. In the prospective study, fetal macrosomia (birth weight >90th centile) was independently related to the mother's fasting glucose (odds ratio 2.61 per +1 mmol/l [95% CI 1.15–5.93]) and prepregnancy BMI (1.10 per +1 kg/m2 [1.04–1.18]). The mother's higher fasting glycemia (P = 0.004), lower insulin sensitivity (P = 0.01), and lower insulin secretion (P = 0.02) were independently related to greater offspring adiposity at birth. During postnatal follow-up, the correlation between the mother's glycemia and offspring adiposity disappeared by 3 months, whereas prepregnancy BMI was associated with offspring adiposity that was only apparent at 12 and 24 months (both P < 0.05).

CONCLUSIONS—Prepregnancy BMI, pregnancy glycemia, insulin sensitivity, and insulin secretion all contribute to offspring adiposity and macrosomia and may be separate targets for intervention to optimize birth outcomes and later offspring health.
Candida antarctica Lipase B (CAL‐B)‐Catalyzed Carbon‐Sulfur Bond Addition and Controllable Selectivity in Organic Media
Authors: Lou Feng‐Wen , Liu Bo‐Kai , Wu Qi , Lv De‐Shui , Lin Xian‐Fu
Published: August 2008

A novel enzymatic, promiscuous protocol for Candida antarctica lipase B (CAL‐B)‐catalyzed carbon‐sulfur bond addition is described. Some control experiments have been designed to demonstrate the catalytic specificity of CAL‐B. Selectivity between anti‐Markovnikov addition and Markovnikov addition was achieved in different organic media. A series of thioether‐containing ester functional groups was synthesized under the catalysis of CAL‐B at 50 °C. All the products were characterized by spectroscopic methods (IR, NMR, ESI‐MS).
Silica Immobilized Second Generation Hoveyda‐Grubbs: A Convenient, Recyclable and Storageable Heterogeneous Solid Catalyst
Authors: Van Berlo Boris , Houthoofd Kristof , Sels Bert F. , Jacobs Pierre A.
Published: August 2008

The second generation Hoveyda–Grubbs metathesis catalyst was successfully immobilized on silica in pellet and powder form following a practical and fast synthesis procedure. The activity of the solid system is truly heterogeneous, efficient in various metathesis reaction types and stable for at least 4000 TON. Ru contamination of the products was very low (ppb levels). The successful use of the robust system has been demonstrated in a continuous reactor set‐up.
Aerobic Oxidation of Alcohols under Mild Conditions Catalyzed by Novel Polymer‐Incarcerated, Carbon‐Stabilized Gold Nanoclusters
Authors: Lucchesi Céline , Inasaki Takeshi , Miyamura Hiroyuki , Matsubara Ryosuke , Kobayashi Shū
Published: August 2008

Polymer‐incarcerated, carbon‐stabilized gold nanoclusters were found to be highly active in heterogeneous catalysis for the oxidation of secondary alcohols using molecular oxygen in aqueous medium. After optimization of catalyst preparation methods, highly loaded and highly effective catalysts were obtained, and a broad range of secondary alcohols could be oxidized by using these catalysts under mild conditions. The catalysts could be recovered and reused several times without significant loss of activity. Moreover, kinetics of the oxidation reaction with (±)‐1‐phenylethanol was investigated.
Ruthenium‐Catalyzed Synthesis of Secondary Alkylamines: Selective Alkylation with Aliphatic Amines
Authors: Bähn Sebastian , Hollmann Dirk , Tillack Annegret , Beller Matthias
Published: August 2008

The chemoselective N‐alkylation of tert‐alkylamines applying aliphatic amines is described for the first time. In the presence of the Shvo catalyst 1, tert‐octylamine 4 and 1‐adamantylamine 5 are alkylated using primary, secondary, and even tertiary amines to give the corresponding monoalkylated tert‐alkylamine in moderate to very good yields and excellent selectivity. This novel reaction proceeds without an additional hydrogen source and ammonia is formed as the only by‐product.
Occupational behaviors and farmworkers' pesticide exposure: Findings from a study in monterey county, California
Authors: Salvatore Alicia L. , Bradman Asa , Castorina Rosemary , Camacho José , López Jesús , Barr Dana B. , Snyder John , Jewell Nicholas P. , Eskenazi Brenda
Published: August 2008

Background

We studied the relationship between behaviors promoted through the US Environmental Protection Agency Worker Protection Standard (WPS) and other programs and agricultural pesticide exposures in 73 strawberry fieldworkers employed in Monterey County, California.

Methods

Farmworkers' behaviors were assessed via self‐report and organophosphorus (OP) pesticide exposure was measured using dimethyl alkylphosphate (DMAP) and malathion dicarboxylic acid (MDA) urinary metabolite levels.

Results

Wearing WPS‐recommended clothing, wearing clean work clothes, and the combination of handwashing with soap and wearing gloves were associated with decreases in DMAP and MDA metabolite levels. Despite these protective behaviors, however, participants had significantly higher levels of exposure as compared with a national reference sample.

Conclusions

Interventions that facilitate compliance with these behaviors may be effective in decreasing fieldworkers' pesticide exposures. However, further efforts are needed to reduce the exposure disparities experienced by farmworkers and decrease the potential for “take home” exposures to farmworkers' families. Am. J. Ind. Med. 51:782–794, 2008. Published 2008 Wiley‐Liss, Inc.
Association of cytokine gene polymorphisms in CWP and its severity in Turkish coal workers
Authors: Ates Ilker , Suzen H. Sinan , Yucesoy Berran , Tekin Ishak Ozel , Karakaya Asuman
Published: August 2008

Background

Cytokines appear to play a key role in some inflammatory reactions affecting the interactions among pro‐ and anti‐inflammatory mechanisms that result in several diseases such as coal workers' pneumoconiosis (CWP). In this study, to determine the cytokine gene profiles of Turkish coal miners, we performed genotyping analysis to investigate the polymorphisms of CWP‐related pro‐inflammatory (TNFA, IL1A, IL1B, and IL6) and anti‐inflammatory cytokines (IL‐1RN and TGFB1). An additional goal was to observe whether these cytokine gene polymorphisms influence the development risk and severity of.

Methods

Genotyping was carried out by polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) technique.

Results

TNFA (−238) gene polymorphism principally affected CWP development and severity (OR = 3.47: 95% CI, 1.12–10.77 and OR = 4.30: 95% CI, 1.25–14.74, respectively) and also risk of CWP (OR = 3.79: 95% CI, 1.37–10.46). The TNFA (−308) variant was associated with a risk for the CWP severity (OR = 2.84: 95% CI, 1.08–7.39). A protective effect of IL6 was found on the development (OR = 0.48: 95% CI, 0.21–0.93) and severity of CWP (OR = 0.37: 95% CI, 0.15–0.91).

Conclusions

We suggest that TNFA (−238) variant may be a risk factor in both development and the severity of CWP, while TNFA (−308) variant seems to be important only in disease severity. On the other hand, IL6 variant may have a protective effect on the development and disease severity. Am. J. Ind. Med. 51:741–747, 2008. Published 2008 Wiley‐Liss, Inc.
The incentive structure in an online information market
Authors: Raban Daphne Ruth
Published: August 2008

The principal objective of this research was to understand the incentive structure in a mixed economic and social market for information. Prior research suggests that tangible incentives will crowd out intangible incentives; however, information markets invite special examination of this finding. Data representing four years of activity by 523 researchers who gave about 52,000 answers on the Google Answers Web site were collected. Analysis revealed that the main predictor for researchers' participation was the anticipation of tip (gratuity). Analysis of two researcher subgroups showed that in the case of the frequent researchers, the tip was followed by social incentives: interaction (comments) and ratings. For occasional researchers, the tip was followed by the price paid for answers and then by comments. The results suggest that a pure economic incentive serves as enticement; however, social incentives induce persistent participation by researchers and eventually lead to higher average economic gains. The market is catalyzed by social activity, not cannibalized by it, as may have been predicted by theory. This finding provides empirical evidence for “social capital” since social incentives were connected to higher economic gains. The practical implication is that a mixed incentive design is likely to generate lively information‐exchange environments.
Impact of different cultivation and induction regimes on the structure of cytosolic inclusion bodies of TEM1‐β‐lactamase
Authors: Margreiter Gerd , Schwanninger Manfred , Bayer Karl , Obinger Christian
Published: August 2008

The enzyme TEM1‐β‐lactamase has been used as a model to study the impact of different cultivation and induction regimes on the structure of cytosolic inclusion bodies (IBs). The protein has been heterologously expressed in Escherichia coli in fed‐batch cultivations at different temperatures (30, 37, and 40°C) as well as induction regimes that guaranteed distinct product formation rates and ratios of soluble to aggregated protein. Additionally, shake flask cultivations at 20, 30, and 37°C were performed. IBs were sampled during the whole bioprocess and structural analysis was performed by attenuated total reflectance Fourier transform infrared (ATR‐FT‐IR) spectroscopy. This work clearly demonstrates that the tested production regimes and rates had no impact on the IB structure, which was characterized by decreased α‐helical and increased and modified β‐sheet contents compared to the native protein. Moreover, aggregates formed during refolding of IBs by solubilization and simple dilution showed very similar FT‐IR spectra suggesting (i) the existence of only one critical folding step from which either aggregation (IB formation) or native folding branches off, and (ii) underlining the important role of the specific amino acid sequence in aggregation. The findings are discussed with respect to the known structure of TEM1‐β‐lactamase and the reported kinetics of its (un)folding as well as contradictory data on the effect of cultivation regimes on IB structure(s) of other proteins.
A rapid, sensitive and economical assessment of monoclonal antibody conformational stability by intrinsic tryptophan fluorescence spectroscopy
Authors: Garidel Patrick , Hegyi Matthias , Bassarab Stefan , Weichel Michael
Published: August 2008

Steady‐state intrinsic tryptophan fluorescence spectroscopy is used as a rapid, robust and economic way for screening the thermal protein conformational stability in various formulations used during the early biotechnology development phase. The most important parameters affecting protein stability in a liquid formulation, e. g. during the initial purification steps or preformulation development, are the pH of the solution, ionic strength, presence of excipients and combinations thereof. A well‐defined protocol is presented for the investigation of the thermal conformational stability of proteins. This allows the determination of the denaturation temperature as a function of solution conditions. Using intrinsic tryptophan fluorescence spectroscopy for monitoring the denaturation and folding of proteins, it is crucial to understand the influence of different formulation parameters on the intrinsic fluorescence probes of proteins. Therefore, we have re‐evaluated and re‐assessed the influence of temperature, pH, ionic strength, buffer composition on the emission spectra of tryptophan, phenylalanine and tyrosine to correctly analyse and evaluate the data obtained from thermal‐induced protein denaturation as a function of the solution parameters mentioned above. The results of this study are a prerequisite for using this method as a screening assay for analysing the conformational stability of proteins in solution. The data obtained from intrinsic protein fluorescence spectroscopy are compared to data derived from calorimetry. The advantage, challenges and applicability using intrinsic tryptophan fluorescence spectroscopy as a routine development method in pharmaceutical biotechnology are discussed.
Role of the ribosome in protein folding
Authors: Das Debasis , Das Anindita , Samanta Dibyendu , Ghosh Jaydip , Dasgupta Santanu , Bhattacharya Arpita , Basu Arunima , Sanyal Suparna , Das Gupta Chanchal
Published: August 2008

In all organisms, the ribosome synthesizes and folds full length polypeptide chains into active three‐dimensional conformations. The nascent protein goes through two major interactions, first with the ribosome which synthesizes the polypeptide chain and holds it for a considerable length of time, and then with the chaperones. Some of the chaperones are found in solution as well as associated to the ribosome. A number of in vitro and in vivo experiments revealed that the nascent protein folds through specific interactions of some amino acids with the nucleotides in the peptidyl transferase center (PTC) in the large ribosomal subunit. The mechanism of this folding differs from self‐folding. In this article, we highlight the folding of nascent proteins on the ribosome and the influence of chaperones etc. on protein folding.
Divergence‐constrained moving least squares for fluid simulation
Authors: Hong Jeong‐Mo , Yoon Jong‐Chul , Kim Chang‐Hun
Published: August 2008

Developing suitable interpolation methods to simulate dynamic motions of continuous materials such as fluids is an important problem. In this paper, we propose a novel method to enforce the divergence condition to the interpolated velocity field by moving least squares (MLS), by means of the diffusive derivatives and moving divergence constraints that allow the practical use and easy implementation. As results, we present the velocity interpolation examples and a fluid‐like particle simulation method to show the meaningful potential of our method as a tool of physical interpolation for fluid simulations. Copyright © 2008 John Wiley & Sons, Ltd.
Inflow conditions for inhomogeneous turbulent flows
Authors: Barri Mustafa , El Khoury George K. , Andersson Helge I. , Pettersen Bjørnar
Published: August 2008

A cost‐effective method to generate inflow conditions for direct numerical simulations of wall‐bounded flows is presented. The method recycles a finite‐length time series of instantaneous velocity planes extracted from a precursor simulation and has earlier proved efficient for free shear layers. Now a spatially developing plane channel flow is considered. Different durations ts of the time series are tested and compared. Excellent agreement with fully developed channel flow statistics is observed when ts equals or exceeds the large‐eddy turnover time scale. The present results are more realistic than those obtained with synthetic turbulence generation and at the same time substantially cheaper than running an auxiliary simulation in parallel. Copyright © 2008 John Wiley & Sons, Ltd.
A comparison of patient and general population weightings of EQ‐5D dimensions
Authors: Mann Rachel , Brazier John , Tsuchiya Aki
Published: August 2008

This paper examines the differences in health state valuations given by patients when they are asked to value their own current states, and those given by members of the general population who were asked to value hypothetical health states. Patient data consist of 4137 observations on EQ‐5D profiles and Visual Analogue Scale (VAS) obtained from 3376 patients, covering eight different conditions. General population data are taken from the EQ‐5D valuation set. Two analyses were carried out. In the first, the patient self‐rated VAS was compared with population VAS values for the same health states. In the second, the patient self‐rated VAS values were modelled, and the regression coefficients were compared with the corresponding coefficients from the general population study. The first analysis resulted in a statistically significant mean difference of −0.012 (0.647 for patient VAS, 0.659 from the population value set). The second analysis found statistically significant differences between the coefficients for the EQ‐5D health dimensions Pain/Discomfort, Mobility and Anxiety/Depression. Anxiety/Depression had the largest impact on the patient model compared with Pain/Discomfort in the general population model. A further regression analysis suggests that the magnitude of disagreement between patient self‐rated VAS model and the population VAS model depends on the patients' condition. Copyright © 2008 John Wiley & Sons, Ltd.
The influence of subjective life expectancy on health state valuations using a 10 year TTO
Authors: van Nooten F. E. , Koolman X. , Brouwer W. B. F.
Published: August 2008

Aim: To investigate if subjective life expectancy (SLE) impacts the willingness to trade‐off (WTT) and the number of years traded‐off in a 10‐years time trade‐off (TTO) exercise to obtain health state valuations.

Methods: An Internet‐based questionnaire was administered in a sample representative for the Dutch general public. Next to basic demographic characteristics and SLE, respondents were asked to perform three TTO exercises. The following EQ‐5D health states were included 21211 (TTO1), 22221 (TTO2) and 33312 (TTO3). The WTT was studied using a probit regression model. The number of years traded‐off was investigated using a generalized negative binomial regression model. The independent variables used in both models were age, gender, quality of life, education, the difference between age and expected age of death (SLE), and a variable indicating whether the SLE was less than 10 years (SLE<10).

Results: Three hundred and thirty nine respondents completed the questionnaire. The mean utility scores were 0.96 (TTO1), 0.94 (TTO2) and 0.79 (TTO3). The probit model showed that SLE was the only variable with a significant influence on WTT. The gnbreg showed that the number of years traded‐off was also significantly influenced by SLE. In addition, age and education significantly influenced the number of years traded‐off.

Conclusion: The WTT years and the number of years traded‐off were both influenced by SLE in 10‐years TTO exercises. Reducing remaining life expectancy to 10 years in a TTO may thus increase loss aversion and, especially in respondents losing relatively many expected life years, diminish WTT and the amount of time traded off. Copyright © 2008 John Wiley & Sons, Ltd.
Nodal expression and heterochrony in the evolution of dorsal–ventral and left–right axes formation in the direct‐developing sea urchin Heliocidaris erythrogramma
Authors: Smith Margaret S. , Turner F. Rudolf , Raff Rudolf A.
Published: August 2008

To understand the role of body axes in the evolution of larval form, we use the two sea urchins in the genus Heliocidaris, which have distinctly different larval morphologies. Heliocidaris tuberculata is an indirect‐developing sea urchin, which forms a pluteus larva, whereas its sister species, Heliocidaris erythrogramma, exhibits direct development and forms a nonfeeding, ovoid larva. Changes along all three larval axes underlie the differences in larval form associated with each developmental mode. Nodal signaling has recently been implicated as important in establishing the dorsal–ventral (D–V) and left–right (L–R) axes in the indirect‐developing sea urchin Paracentrotus lividus. However, because of changes in morphology and timing of morphogenetic events associated with the D–V and L–R axes, respectively, in H. erythrogramma, it was unclear whether nodal played the same roles during direct development. We show that the expression patterns and functions of nodal during H. erythrogramma development are similar to its roles in indirect‐developing sea urchins in both D–V and L–R axes formation. However, there are profound changes in gene expression downstream of nodal signaling along the D–V axis and major heterochronies in the execution of the function of nodal along the L–R axis. These highly modified events are linked to the dramatic modifications of larval morphology that have occurred during the evolution of direct development in H. erythrogramma. J. Exp. Zool. (Mol. Dev. Evol.) 310B:609–622, 2008. © 2008 Wiley‐Liss, Inc.
Failure at the transition of care: Challenges in the discharge of the vulnerable elderly patient
Authors: Cumbler Ethan , Carter Jeff , Kutner Jean
Published: August 2008

The case of an elderly patient with mild dementia and severe depression is reviewed including analysis of the barriers to successful transition that led to readmission. Situations likely to result in failed transitions include poor social support, discharge during times when ancillary services are unavailable, uncertain medication reconciliation, depression, and patients' cognitive limitations. Evidence suggests deficits in communication by hospital physicians to primary care providers occur commonly but this is only one of many systems barriers to successful discharge. Review of the literature reveals interventions such as involvement of advance practice nurses or family members in the transition may overcome some of the difficulties inherent in discharge of the vulnerable geriatric patient. Weekend discharges present unique challenges and potential solutions are explored. This case offers the opportunity to review the elements necessary for success and insight into the systems limitations which underlie failed transitions. Journal of Hospital Medicine 2008;3:349–352. © 2008 Society of Hospital Medicine.