bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of several microorganisms and activity of alkaline phosphatase in sediments from Baihua Lake
Authors: Deng Jia‐jun , Huang Xian‐fei , Hu Ji‐wei , Li Cun‐xiong , Yi Yin , Long Jian 
Published: July 2009

AbstractThe distribution characteristics of ammonifiers, ammonium‐oxidizing bacteria, nitrite‐oxidizing bacteria, and denitrifiers, and activities of alkaline phosphatase (ALP) in sediments from Baihua Lake (a man‐made deep plateau canyon reservoir in Guizhou Province, China) were studied. The results suggested that the population number of ammonifiers in the sediments was higher at sampling sites Pingpu, Laojiutu, Yapengzhai, and Jiangjiapu than at the other sites. Ammonium‐oxidizing bacteria had the highest population number at sampling site Meituwan. The population number of nitrite‐oxidizing bacteria in the upper and middle sections of the lake was higher than that in the lower section. The population of denitrifiers was the highest at sampling site Jiangjiapu, and all the other sampling sites gave lower population numbers.Change in the activity of ALP was of a strong regularity, and the basic tendency was that the activity increased from the upper to the lower portion of the lake. Specifically, the activity at sampling site Yapengzhai was the strongest. The statistical analysis for four groups of bacteria, ALP, organic matter, and so on were carried out to shed more light on their correlativity. This research will likely provide relevant data useful for establishment of bacteriological and zymological indicator systems for environmental monitoring. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Effects of physical properties estimation on process design: a case study using AspenPlus
Authors: Cadoret Loic , Yu Cheng‐Ching , Huang Hsiao‐Ping , Lee Ming‐Jer 
Published: July 2009

AbstractThis study focuses on the physical property model parameters estimation in order to accurately simulate separation processes for a given set of components. The non‐random two‐liquid (NRTL) model was chosen and parameters were calculated using different methods: experimental data regression and UNIFAC and COSMO‐SAC (conductor‐like screening model, segment activity coefficient) predictive models. The vapor‐liquid equilibrium (VLE) obtained from these different models was compared and results showed that COSMO‐SAC can be a reliable tool when data or functional groups are missing. Results also showed that the use of UNIFAC to estimate activity coefficients at infinite dilution can, in some cases, leads to inaccurate results and strongly impact process simulation results. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
A relation between h‐index and impact factor in the power‐law model
Authors: Egghe Leo , Liang Liming , Rousseau Ronald 
Published: July 2009

AbstractUsing a power‐law model, the two best‐known topics in citation analysis, namely the impact factor and the Hirsch index, are unified into one relation (not a function). The validity of our model is, at least in a qualitative way, confirmed by real data.
Truxene‐Based Columnar Liquid Crystals: Self‐Assembled Structures and Electro‐Active Properties
Authors: Isoda Kyosuke , Yasuda Takuma , Kato Takashi 
Published: July 2009

AbstractColumnar liquid‐crystalline (LC) truxene derivatives containing branched flexible alkyl chains have been designed and synthesized. The dicyanomethylene and dithiafulvene substituents have been introduced into the π‐conjugated truxene framework to tune their electronic and redox properties as well as the molecular assembled structures. The π‐conjugated cores of dicyanomethylene‐ and dithiafulvene‐appended truxenes adopt bowl‐shaped conformations, giving rise to a large intrinsic dipole moment perpendicular to the aromatic framework. These molecules form stable columnar LC structures through intermolecular dipole–dipole interactions. The redox properties of LC truxene derivatives have been examined by cyclic voltammetry. The dicyanomethylene‐appended truxene shows the reversible four‐step electrochemical reductions, whereas the dithiafulvene‐appended truxene undergoes three‐step oxidations.
On the robustness of description and experience based decision tasks to social desirability
Authors: Koritzky Gilly , Yechiam Eldad 
Published: July 2009

AbstractWe compared the sensitivity of two classes of decision tasks to social desirability: description‐based tasks and experience‐based tasks. Participants completed a battery of decision tasks in two conditions: a Control condition in which they were asked to perform their best, and an Impression condition in which they were required to impress judges in the context of hiring decisions. The Impression condition was predicted to elicit relatively lower levels of risk taking than the Control condition. This was confirmed for the description‐based tasks while the experience‐based tasks were fairly robust to the impression manipulation. This finding points to the potential of experience‐based tasks' for assessing individual differences, particularly in situations where social desirability is prevalent. A second finding is that risk taking levels showed consistency across the description‐experience divide, but in line with the different sensitivity of the tasks to social desirability, this was only observed in the Control condition. Copyright © 2009 John Wiley & Sons, Ltd.
Big risks in small groups: The difference between epidemiology and counselling
Authors: Friedman J. M. 
Published: July 2009

AbstractCongenital anomalies do not occur in all babies born after a teratogenic exposure. Whether a given exposure is teratogenic depends on the chemical nature and physical properties of the agent, the dose and route of exposure, when in pregnancy the exposure occurs, and genetic and other factors that affect susceptibility. Teratogenic birth defects are inherently multifactorial. Absolute risk, relative risk, and population attributable risk provide useful but different information regarding teratogenic effects. Statistical significance and clinical significance also are important considerations, but they may not be concordant. Demonstrating a teratogenic effect is easier if it is sought in a subgroup of patients in whom the effect is likely to be particularly prominent. The ability to detect a significant risk is, therefore, generally increased by subgroup analysis of epidemiology studies, but the greater the number of analyses performed, the higher the probability of finding associations that reach nominal statistical significance by chance alone. This problem is well recognized, but it is difficult to solve. The only compelling evidence for the reality of an association between maternal exposure to an agent during pregnancy and teratogenic effects in the children is replication of the findings in independent studies, but this is hard to obtain. As a consequence, there are very few exposures for which the available information is sufficient to make evidence‐based recommendations regarding the clinical management of teratogenic risks. It is important to admit these limitations and to learn more about exposures that cause birth defects and how to prevent them. Birth Defects Research (Part A) 2009. © 2009 Wiley‐Liss, Inc.
Mitosis in diatoms: rediscovering an old model for cell division
Authors: De Martino Alessandra , Amato Alberto , Bowler Chris 
Published: July 2009

AbstractDiatoms are important protists that generate one fifth of the oxygen produced annually on earth. These aquatic organisms likely derived from a secondary endosymbiosis event, and they display peculiar genomic and structural features that reflect their chimeric origin. Diatoms were one of the first models of cell division and these early studies revealed a range of interesting features including a unique acentriolar microtubule‐organising centre. Unfortunately, almost nothing is known at the molecular level, in contrast to the advances in other experimental organisms. Recently the full genome sequences of two diatoms have been annotated and molecular tools have been developed. These resources offer new possibilities to re‐investigate the mechanisms of cell division in diatoms by recruiting information from more intensively studied organisms. A renaissance of the topic is further justified by the current interest in diatoms as a source of biofuels and for understanding massive diatom proliferation events in response to environmental stimuli.
Comparing Accuracy in an Unpaired Post‐market Device Study with Incomplete Disease Assessment
Authors: Alonzo Todd A. 
Published: July 2009

AbstractThe sensitivity and specificity of a new medical device are often compared relative to that of an existing device by calculating ratios of sensitivities and specificities. Although it would be ideal for all study subjects to receive the gold standard so true disease status was known for all subjects, it is often not feasible or ethical to obtain disease status for everyone. This paper proposes two unpaired designs where each subject is only administered one of the devices and device results dictate which subjects are to receive disease verification. Estimators of the ratio of accuracy and corresponding confidence intervals are proposed for these designs as well as sample size formulae. Simulation studies are performed to investigate the small sample bias of the estimators and the performance of the variance estimators and sample size formulae. The sample size formulae are applied to the design of a cervical cancer study to compare the accuracy of a new device with the conventional Pap smear.
Resonance light scattering study on the interaction between quinidine sulfate and congo red and its analytical application
Authors: Zeng Yanbo , Cai Liling , Wang Haidong , Li Lei , You Weijing , Guo Longhua , Chen Guonan 
Published: July 2009

AbstractThe interaction between quinidine sulfate (QDS) and congo red (CR) was studied using resonance light scattering (RLS) technique, ultraviolet–visual spectrophotometry and fluorimetry. In weak acidic medium, QDS reacts with CR to form a supermolecular complex which results in the enhanced RLS intensity. Some important interacting parameters, such as the solution acidity and CR concentration, salt effect and addition order of the reagents, were investigated and optimized. Under the optimum conditions, it was found that the enhanced RLS intensity was in proportion to the concentration of QDS in the range 0.2–8.4 µg mL−1. The corresponding detection limit was 12.0 ng mL−1. The results showed that this new method enabled simple, sensitive and rapid determination of QDS and was used for the determination of QDS in urine and simulated huamn serum samples. Copyright © 2009 John Wiley & Sons, Ltd.
Life‐cycle kinetic model for endospore‐forming bacteria, including germination and sporulation
Authors: Park Seongjun , Rittmann Bruce E. , Bae Wookeun 
Published: July 2009

AbstractWe develop a mechanistic life‐cycle model for endospore‐forming bacteria (EFB) and test the model with experiments with a Bacillus mixed culture. The model integrates and quantifies how sporulation and germination are triggered by depletion or presence of a limiting substrate, while both substrates affect the rate of vegetative growth by a multiplicative model. Kinetic experiments show the accumulation of small spherical spores after the triggering substrate is depleted, substantially more rapid decay during sporulation than for normal decay of vegetative cells, and a higher specific substrate utilization rate for the germinating cells than that for growth of vegetative cells. Model simulations capture all of these experimental trends. According to model predictions, when a batch reactor is started, seeding with EFB spores instead of active EFB delays the onset of rapid chemical oxygen demand (COD) utilization and biomass growth, but the end points are the same. Simulated results with low aeration intensity show that germination can consume some substrate without dissolved oxygen (DO) depletion. Biotechnol. Bioeng. 2009; 104: 1012–1024. © 2009 Wiley Periodicals, Inc.
A new metabolite of nodakenetin by rat liver microsomes and its quantification by RP‐HPLC method
Authors: Zhang Peng , Yang Xiu‐Wei 
Published: July 2009

AbstractThe biotransformation of nodakenetin (NANI) by rat liver microsomes in vitro was investigated. Two major polar metabolites were produced by liver microsomes from phenobarbital‐pretreated rats and detected by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) analysis. The chemical structures of two metabolites were firmly identified as 3′(R)‐hydroxy‐nodakenetin‐3′‐ol and 3′(S)‐hydroxy‐nodakenetin‐3′‐ol, respectively, on the basis of their 1H‐NMR, MS and optical rotation analysis. The latter was a new compound. A sensitive, selective and simple RP‐HPLC method has been developed for the simultaneous determination of NANI and its two major metabolites in rat liver microsomes. Chromatographic conditions comprise a C18 column, a mobile phase with MeOH‐H2O (40 : 60, v/v), a total run time of 40 min, and ultraviolet absorbance detection at 330 nm. In the rat heat‐inactivated liver microsomal supernatant, the lower limits of detection and quantification of metabolite I, metabolite II and NANI were 5.0, 2.0, 10.0 ng/mL and 20.0, 5.0, 50.0 ng/mL, respectively, and their calibration curves were linear over the concentration range 50–400, 20–120 and 150–24000 ng/mL, respectively. The results provided a firm basis for further evaluating the pharmacokinetics and clinical efficacy of NANI. Copyright © 2009 John Wiley & Sons, Ltd.
Pellet culture elicits superior chondrogenic redifferentiation than alginate‐based systems
Authors: Bernstein Peter , Dong Meng , Corbeil Denis , Gelinsky Michael , Günther Klaus‐Peter , Fickert Stefan 
Published: July 2009

AbstractAlthough pellet culture and encapsulation of chondrocytes into gel‐like biomaterials have lead to major advances in cartilage tissue engineering, a quantitative comparative characterization of cellular differentiation behavior during those cultivation procedures has not yet been performed. Our study therefore aimed at answering the following question: is the redifferentiation pathway of chondrocytes altered by slight changes in the type of alginate biomaterial (pure alginate, alginate‐fibrin, alginate‐chitosan) and how do the cells behave in comparison to biomaterial‐free (pellet) three‐dimensional culturing? Monolayer‐expanded chondrocytes from healthy adult porcine knee joints were cultivated in alginate, alginate‐chitosan, alginate‐fibrin beads and as pellets up to 4 weeks. Quantitative PCR and Immunohistology were used to assess chondrogenic markers. Alginate‐fibrin—encapsulated chondrocytes behaved almost like monolayer chondrocytes. Alginate‐ and alginate‐chitosan encapsulation lead to a low chondrogenic marker gene expression. Although all 3D‐cultured chondrocytes showed a considerable amount of Sox9 expression, only pellet cultivation lead to a sufficient Collagen II expression. This puts the usage of alginate‐cultivated cartilage tissue engineering constructs under question. Fibrin addition is not beneficial for chondrogenic differentiation. Sox9 and Collagen II behave differently, depending upon the surrounding 3D‐environment. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Promoting α‐secretase cleavage of beta‐amyloid with engineered proteolytic antibody fragments
Authors: Kasturirangan Srinath , Brune Dan , Sierks Michael 
Published: July 2009

AbstractDeposition of beta‐amyloid (Aβ) is considered as an important early event in the pathogenesis of Alzheimer's Disease (AD), and reduction of Aβ levels by various therapeutic approaches is actively being pursued. A potentially non‐inflammatory approach to facilitate clearance and reduce toxicity is to hydrolyze Aβ at its α‐secretase site. We have previously identified a light chain fragment, mk18, with α‐secretase‐like catalytic activity, producing the 1–16 and 17–40 amino acid fragments of Aβ40 as primary products, although hydrolysis is also observed following other lysine and arginine residues. To improve the specific activity of the recombinant antibody by affinity maturation, we constructed a single chain variable fragment (scFv) library containing a randomized CDR3 heavy chain region. A biotinylated covalently reactive analog mimicking α‐secretase site cleavage was synthesized, immobilized on streptavidin beads, and used to select yeast surface expressed scFvs with increased specificity for Aβ. After two rounds of selection against the analog, yeast cells were individually screened for proteolytic activity towards an internally quenched fluorogenic substrate that contains the α‐secretase site of Aβ. From 750 clones screened, the two clones with the highest increase in proteolytic activity compared to the parent mk18 were selected for further study. Kinetic analyses using purified soluble scFvs showed a 3‐ and 6‐fold increase in catalytic activity (kcat/KM) toward the synthetic Aβ substrate compared to the original scFv primarily due to an expected decrease in KM rather than an increase in kcat. This affinity maturation strategy can be used to select for scFvs with increased catalytic specificity for Aβ. These proteolytic scFvs have potential therapeutic applications for AD by decreasing soluble Aβ levels in vivo. © 2009 American Institute of Chemical Engineers. Biotechnol. Prog., 2009
Time‐lapsed imaging for in‐process evaluation of supercritical fluid processing of tissue engineering scaffolds
Authors: Mather Melissa L. , Brion Michael , White Lisa J. , Shakesheff Kevin M. , Howdle Steven M. , Morgan Stephen P. , Crowe John A. 
Published: July 2009

AbstractThis article demonstrates the application of time‐lapsed imaging and image processing to inform the supercritical processing of tissue scaffolds that are integral to many regenerative therapies. The methodology presented provides online quantitative evaluation of the complex process of scaffold formation in supercritical environments. The capabilities of the developed system are demonstrated through comparison of scaffolds formed from polymers with different molecular weight and with different venting times. Visual monitoring of scaffold fabrication enabled key events in the supercritical processing of the scaffolds to be identified including the onset of polymer plasticization, supercritical points and foam formation. Image processing of images acquired during the foaming process enabled quantitative tracking of the growing scaffold boundary that provided new insight into the nature of scaffold foaming. Further, this quantitative approach assisted in the comparison of different scaffold fabrication protocols. Observed differences in scaffold formation were found to persist, post‐fabrication as evidenced by micro x‐ray computed tomography (μ x‐ray CT) images. It is concluded that time‐lapsed imaging in combination with image processing is a convenient and powerful tool to provide insight into the scaffold fabrication process. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Biochemical, mechanical, and spectroscopic analyses of genetically engineered flax fibers producing bioplastic (poly‐β‐hydroxybutyrate)
Authors: Wróbel‐Kwiatkowska Magdalena , Skórkowska‐Telichowska Katarzyna , Dymińska Lucyna , Mączka Mirosław , Hanuza Jerzy , Szopa Jan 
Published: July 2009

AbstractThe interest in biofibers has grown in recent years due to their expanding range of applications in fields as diverse as biomedical science and the automotive industry. Their low production costs, biodegradability, physical properties, and perceived eco‐friendliness allow for their extensive use as composite components, a role in which they could replace petroleum‐based synthetic polymers. We performed biochemical, mechanical, and structural analyses of flax stems and fibers derived from field‐grown transgenic flax enriched with PHB (poly‐β‐hydroxybutyrate). The analyses of the plant stems revealed an increase in the cellulose content and a decrease in the lignin and pectin contents relative to the control plants. However, the contents of the fibers' major components (cellulose, lignin, pectin) remain unchanged. An FT‐IR study confirmed the results of the biochemical analyses of the flax fibers. However, the arrangement of the cellulose polymer in the transgenic fibers differed from that in the control, and a significant increase in the number of hydrogen bonds was detected. The mechanical properties of the transgenic flax stems were significantly improved, reflecting the cellulose content increase. However, the mechanical properties of the fibers did not change in comparison with the control, with the exception of the fibers from transgenic line M13. The generated transgenic flax plants, which produce both components of the flax/PHB composites (i.e., fibers and thermoplastic matrix in the same plant organ) are a source of an attractive and ecologically safe material for industry and medicine. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Effects of citraconylation on enzymatic modification of human proinsulin using trypsin and carboxypeptidase B
Authors: Son Young‐Jin , Kim Chang‐Kyu , Kim Young Bong , Kweon Dae‐Hyuk , Park Yong‐Cheol , Seo Jin‐Ho 
Published: July 2009

AbstractInsulin is a polypeptide hormone which is produced by the β‐cell of pancreas and controls the blood glucose level in the human body. Enzymatic modification of human proinsulin using trypsin and carboxypeptidase B generally causes high accumulation of insulin derivatives, leading to more complicated purification processes. A simple method including citraconylation and decitraconylation in the enzymatic modification process was developed for the reduction of a major derivative, des‐threonine human insulin. Addition of 3.0 g citraconic anhydride per g protein into the reaction solution led to the citraconylation of lysine residues in human proinsulin and reduction of relative des‐threonine insulin content from 13.5 to 1.0%. After the enzymatic hydrolysis of the citraconylated proinsulin, 100% of lysine residues can be decitraconylated and restored by adjusting pH to 2–3 at 25 °C. Combination of hydrogen peroxide addition and citraconylation of proinsulin expressed in recombinant Escherichia coli remarkably improved the conversion yield of insulin from 52.7 to 77.7%. Consequently, citraconylation of lysine residues blocked the unexpected cleavage of human proinsulin by trypsin, minimized the formation of des‐threonine insulin and hence increased the production yield of active insulin. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009