bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microfluidic Reactor for Continuous Flow Biotransformations with Immobilized Enzymes: the Example of Lactose Hydrolysis by a Hyperthermophilic β_cont;‐Glycoside Hydrolase
Authors: Thomsen M. S. , Nidetzky B. 
Published: February 2008

AbstractA microfluidic reactor was developed for continuous flow biocatalytic transformations with immobilized enzymes. The microreaction device integrated a microstructured multichannel plate fabricated by microinjection molding from liquid silicon rubber material, with an appropriately interfaced and temperature‐controlled housing. Enzyme immobilization was carried out under flow conditions using the fully assembled microreactor. Covalent protein attachment was utilized, via cross‐linking with glutardialdehyde onto the amino‐silanized microstructured surface of the reaction plate. Scanning electron microscopy (SEM) and continuous flow enzyme kinetic studies were employed to characterize the immobilization of a thermophilic β‐glycoside hydrolase. SEM analysis revealed enzyme binding in aggregated clusters, preferentially around passive mixing elements that were introduced in an alternating left‐and‐right pattern along each microchannel. Using an immobilization protocol optimized with respect to the pH in each step, about 1600 units of activity were bound per m2 of microstructure. Although retention of activity in the surface‐bound enzyme was only 3–4 %, the Michaelis‐Menten constant for lactose was similar (≈ 70 mM) in free and immobilized hydrolase. The free energy of activation for lactose hydrolysis (Ea) was decreased from 72 kJ/mol in the free enzyme to 38 kJ/mol in the immobilized enzyme. Covalent attachment of the enzyme onto the microchannel walls via a dendrimeric linker restored the original Ea value. The immobilized enzyme microreactor was used for continuous conversion of 100 mM lactose at 80 °C and operated at a stable substrate conversion of 60 % for five days.
Protein‐Processing Platform (3P) – a New Concept for the Characterization of Cell Cultures in the mL‐Scale Using Microfluidic Components
Authors: Gastrock G. , Lemke K. , Römer R. , Howitz S. , Bertram J. , Hottenrott M. , Metze J. 
Published: February 2008

AbstractA newly developed Protein‐Processing Platform (3P) for cell cultivation and sample handling is presented. The 3P‐concept is based on a 6‐well microtiter plate for cell cultivation, an autoclavable top plate as a sampling system using a new kind of microvalve and an x‐y‐z‐plotter to manage the sample handling procedures. Furthermore, the sample can be stored in a water‐cooled deep well plate and transported to a detector e.g. by addressing a dedicated protein chip based on a Black‐Silicon structure. The function of microvalves is based on the swelling behavior of hydrogel depending on its temperature. The regulation system of this temperature is integrated into the 6‐well microtiter top plate. In this paper, the realization of this concept is exemplarily carried out using the cultivation of hybridoma and their production of monoclonal antibodies. The cultivation conditions were not optimized. However, using different mixing methods, their influence on the antibody production was investigated. The best cell growth was observed in the dormant 6‐well microtiter plate. As under these conditions, a gradient of antibody concentrations occurs, the depth of immersion of the sampling probes has to be investigated. A reproducible sampling was possible by withdrawing the sample from the middle of the cell suspension level. Procedures for sampling and washing under sterile conditions were developed using the tools of the x‐y‐z‐plotter. The optical detection of the samples can be performed using the new protein chip based on the Black‐Silicon technology in any kind of commercial reader. It is possible to integrate the single modular components of the platform into every protein expression process. Additionally, the adaptation of the sampling system to commercial microtiter plates guarantees a wide range of applications.
Variance‐reduced Monte Carlo solutions of the Boltzmann equation for low‐speed gas flows: A discontinuous Galerkin formulation
Authors: Baker Lowell L. , Hadjiconstantinou Nicolas G. 
Published: February 2008

AbstractWe present and discuss an efficient, high‐order numerical solution method for solving the Boltzmann equation for low‐speed dilute gas flows. The method's major ingredient is a new Monte Carlo technique for evaluating the weak form of the collision integral necessary for the discontinuous Galerkin formulation used here. The Monte Carlo technique extends the variance reduction ideas first presented in Baker and Hadjiconstantinou (Phys. Fluids 2005; 17, art. no. 051703) and makes evaluation of the weak form of the collision integral not only tractable but also very efficient. The variance reduction, achieved by evaluating only the deviation from equilibrium, results in very low statistical uncertainty and the ability to capture arbitrarily small deviations from equilibrium (e.g. low‐flow speed) at a computational cost that is independent of the magnitude of this deviation. As a result, for low‐signal flows the proposed method holds a significant computational advantage compared with traditional particle methods such as direct simulation Monte Carlo (DSMC). Copyright © 2008 John Wiley & Sons, Ltd.
Physically Motivated Reduction of a 2D Dynamic Model for Molten Carbonate Fuel Cells (MCFC)
Authors: Gundermann M. , Heidebrecht P. , Sundmacher K. 
Published: February 2008

AbstractThe reduction of a molten carbonate fuel cell (MCFC) model is presented. It starts from a reference model, which includes direct and indirect internal reforming as well as a catalytic combustion and a reversal chamber between anode and cathode channels. The reference model is dynamic, spatially distributed and strictly based on balances of mass, enthalpy and charges. In order to reduce the numerical effort of the model simulations and to retain as much detailed information on the system behaviour as possible, the model is systematically reduced by identifying negligible physical and chemical processes. All model reductions are discussed in detail. To evaluate the effects of the applied changes, the reduced model is compared to the reference model.
Recent advances in stream and river temperature research
Authors: Webb Bruce W. , Hannah David M. , Moore R. Dan , Brown Lee E. , Nobilis Franz 
Published: February 2008

AbstractResearch on stream and river temperatures is reviewed with particular attention being given to advances in understanding gained since 1990 and on investigations of fundamental controls on thermal behaviour, thermal heterogeneity at different spatial scales, the influence of human impacts and the nature of past and future trends. Copyright © 2008 John Wiley & Sons, Ltd.
Effects of climate change on nitrate loads in a large river: the Austrian Danube as example
Authors: Zweimüller Irene , Zessner Matthias , Hein Thomas 
Published: February 2008

AbstractUsing long‐term data from 1951 to 2006, a considerable increase in water temperature was observed in the Austrian Danube (approximately 0·1 °C per decade). The mean annual discharge rates remained fairly constant over the years, but the seasonal pattern changed: in the summer, discharge decreased whereas the opposite trend was observed during the winter months.Data from routine water samples taken in approximately monthly intervals (1991–2006) revealed high temperature dependence of nitrate and dissolved inorganic nitrogen (DIN), intermediate temperature effect on nitrite and low temperature dependence of ammonia.The temperature dependence of nitrate differed between three discharge groups (low, middle and high discharge). It was nearly linear in the low‐discharge group; in the other two discharge groups the decrease of nitrate with increasing temperature was more pronounced, but levelled off at approximately 15 to 20 °C in the middle and high discharge groups.Scenarios assuming increasing mean air temperature of 0·5 and 1·0 °C were calculated for water temperature and air temperature, discharge rates and nitrate loads based on trends detected in the air temperature and discharge data from 1951 to 2006. According to these scenarios, temperatures (both water and air) will continue to increase. The discharge regime of the Danube will be affected by significantly increasing discharge rates in March and significantly decreasing rates for July. The annual mean discharge rate will not be affected. Trends for nitrate loads showed similar tendencies: while annual mean nitrate load does not change with time, the seasonal pattern of nitrate loads is expected to change. Larger amounts of nitrate will be transported downstream in winter, whereas the loads during summer will decrease. The ecological consequences of such shifts are not fully understood. Copyright © 2008 John Wiley & Sons, Ltd.
Testing the incremental utility of the negative impression–positive impression differential in detecting simulated personality assessment inventory profiles
Authors: Hopwood Christopher J. , Talbert Christy A. , Morey Leslie C. , Rogers Richard 
Published: February 2008

AbstractThe usefulness of multiscale inventories depends on their ability to evaluate response styles effectively, such as fake‐bad (feigning) and fake‐good (defensiveness) profiles. The current investigation combined validity data across clinical, nonclinical, and simulating samples to evaluate the usefulness of the Personality Assessment Inventory (PAI) negative impression (NIM)–positive impression (PIM) difference score to detect simulated profiles. In general, its effect sizes were not appreciably different from those afforded by NIM and PIM alone. Likewise, its incremental contributions in logistic regression were minimal. These results do not support the routine use of a NIM‐PIM difference score in detecting response styles with the PAI. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64: 338–343, 2008.
Sperm ultrastructure in the inseminating Macropsobrycon uruguayanae (Teleostei: Characidae: Cheirodontinae)
Authors: de Oliveira Cristina L.C. , Burns John R. , Malabarba Luiz R. , Weitzman Stanley H. 
Published: February 2008

AbstractMacropsobrycon uruguayanae is a small, inseminating characid (tetra) of the tribe Compsurini. Although spermatozoa can be found within the ovarian cavity close to oocytes, the exact moment of fertilization has not yet been determined. Spermatozoa have moderately elongate nuclei with electron‐dense chromatin. During spermiogenesis, nuclear rotation takes place. Elongate mitochondria with lamellar cristae are found posterior to the nucleus. Centrioles are parallel to one another with the proximal centriole slightly anterior to the longer distal one. The anterior tip of the proximal centriole is located within a shallow nuclear fossa. Electron‐dense spurs are associated within the anterior and posterior ends of the distal centriole. Striated centriolar rootlets radiate both anteriorly and posteriorly from the distal centriole. Nine longitudinal accessory microtubules surround the axoneme in the proximal flagellum. The flagellum has a typical 9 + 2 axoneme with no intratubular differentiation. Atypical spermatozoa are also found in the testicular lumen. These cells resemble spermatozoa in most aspects, except that their nuclei are variable in shape, with the granular chromatin less electron‐dense than that seen in spermatozoa. The origin and function of these cells could not be determined. The specializations seen in the spermatozoa are discussed as possible adaptations related to the habit of insemination. J. Morphol., 2008. © 2008 Wiley‐Liss, Inc.
MR volume of the fetal cerebellum in relation to growth
Authors: Hatab Mustapha R. , Kamourieh Salwa W. , Twickler Diane M. 
Published: February 2008

AbstractPurposeTo quantify fetal cerebellar growth by measuring cerebellar volumes of normal fetuses throughout gestation with MRI.Materials and MethodsA total of 93 fetuses with normal brains ranging in age from 16 to 40 gestational weeks were included in the study. Standard fetal biometric measurements were made on a three‐dimensional postprocessing workstation and included the head circumference, transverse cerebellar diameter, biparietal diameter, occipital‐frontal diameter, as well as cerebellar volume. The gestational ages were estimated from fetal head circumference measurements. Regression analysis was used to find the best‐fit model.ResultsThere is a strong correlation describing cerebellar volume and gestational age in fetuses with normal central nervous systems. A second‐order polynomial regression model was found to be the most appropriate descriptor of cerebellar volume in relation to normal fetal growth. In addition, the cerebellar volume was also found to correlate strongly with the common fetal biometric measurements of transverse cerebellar diameter, biparietal diameter, and occipital‐frontal diameter.ConclusionNomograms for fetal cerebellar volume with gestational age derived from head circumference measurements are presented for the first time with MRI. A normal fetal cerebellar volume growth chart is established. These results should prove helpful in defining situations of abnormal growth development and dysmorphology. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
How accurate is dynamic contrast‐enhanced MRI in the assessment of renal glomerular filtration rate? A critical appraisal
Authors: Mendichovszky Iosif , Pedersen Michael , Frøkiær Jørgen , Dissing Thomas , Grenier Nicolas , Anderson Peter , McHugh Kieran , Yang Qing , Gordon Isky 
Published: February 2008

AbstractPurposeTo evaluate the current literature to see if the published results of MRI‐glomerular filtration rate (GFR) stand up to the claim that MRI‐GFR may be used in clinical practice. Claims in the current literature that Gadolinium (Gd) DTPA dynamic contrast enhanced (DCE) MRI clearance provides a reliable estimate of glomerular filtration are an overoptimistic interpretation of the results obtained. Before calculating absolute GFR from Gd‐enhanced MRI, numerous variables must be considered.Materials and MethodsWe examine the methodology in the published studies on absolute quantification of MRI‐GFR. The techniques evaluated included the dose and volume of Gd‐DTPA used, the speed of injection, acquisition sequences, orientation of the subject, re‐processing, conversion of signal to concentration and the model used for analysis of the data as well as the MRI platform.ResultsClaims in the current literature that using DCE MRI “Gd DTPA clearance provides a good estimate of glomerular filtration” are not supported by the data presented and a more accurate conclusion should be that “no MRI approach used provides a wholly satisfactory measure of renal GFR function.”ConclusionThis study suggests that DCE MRI‐GFR results are not yet able to be used as a routine clinical or research tool. The published literature does not show what change in DCE MRI‐GFR is clinically significant, nor do the results in the literature allow a single DCE MRI‐GFR measurement to be correlated directly with a multiple blood sampling technique. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
MR analysis of regional brain volume in adolescent idiopathic scoliosis: Neurological manifestation of a systemic disease
Authors: Liu Tianming , Chu Winnie C.W. , Young Geoffrey , Li Kaiming , Yeung Benson H.Y. , Guo Lei , Man Gene C.W. , Lam Wynnie W.M. , Wong Stephen T.C. , Cheng Jack C.Y. 
Published: February 2008

AbstractPurposeTo investigate whether regional brain volumes in adolescent idiopathic scoliosis (AIS) patients differ from matched control subjects as AIS subjects are reported to have poor performance on combined visual and proprioceptive testing and impaired postural balance in previous studies.Materials and MethodsTwenty AIS female patients with typical right‐convex thoracic curve (age range,11–18 years; mean, 14.1 years) and 26 female controls (mean age, 14.8 years) underwent three‐dimensional magnetization prepared rapid acquisition gradient echo (3D‐MPRAGE) MR imaging. Volumes of 99 preselected neuroanatomical regions were compared by statistical parametric mapping and atlas‐based hybrid warping.ResultsAnalysis of variance statistics revealed significant mean volumetric differences in 22 brain regions between AIS and controls. Ten regions were larger in AIS including the left frontal gyri and white matter in left frontal, parietal, and temporal regions, corpus callosum and brainstem. Twelve regions were smaller in AIS, including right‐sided descending white matter tracts (anterior and posterior limbs of the right internal capsule and the cerebral peduncle) and deep nucleus (caudate), bilateral perirhinal cortices, left hippocampus and amygdala, bilateral precuneus gyri, and left middle and inferior occipital gyri.ConclusionRegional brain volume difference in AIS subjects may help to explain neurological abnormalities in this group. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
Nerve growth factor improves ligament healing
Authors: Mammoto Takeo , Seerattan Ruth A. , Paulson Kent D. , Leonard Catherine A. , Bray Robert C. , Salo Paul T. 
Published: February 2008

AbstractPrevious work has shown that innervation participates in normal ligament healing. The present study was performed to determine if exogenous nerve growth factor (NGF) would improve the healing of injured ligament by promoting reinnervation, blood flow, and angiogenesis. Two groups of 30 Sprague–Dawley rats underwent unilateral medial collateral ligament transection (MCL). One group was given 10 µg NGF and the other was given PBS via osmotic pump over 7 days after injury. After 7, 14, and 42 days, in vivo blood flow was measured using laser speckle perfusion imaging (LSPI). Morphologic assessments of nerve density, vascularity, and angiogenesis inhibitor production were done in three animals at each time point by immunohistochemical staining for the pan‐neuronal marker PGP9.5, the endothelial marker vWF, and the angiogenesis inhibitor thrombospondin‐2 (TSP‐2). Ligament scar material and structural mechanical properties were assessed in seven rats at each time point. Increased nerve density was promoted by NGF at both 14 and 42 days. Exposure to NGF also led to increased ligament vascularity, as measured by histologic assessment of vWF immunohistochemistry, although LSPI‐measured blood flow was not significantly different from controls. NGF treatment also led to decreased expression of TSP‐2 at 14 days. Mechanical testing revealed that exposure to NGF increased failure load by 40%, ultimate tensile strength by 55%, and stiffness by 30% at 42 days. There were no detectable differences between groups in creep properties. The results suggest that local application of NGF can improve ligament healing by promoting both reinnervation and angiogenesis, and results in scars with enhanced mechanical properties. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:957–964, 2008
Avoidant coping and PTSD symptoms related to domestic violence exposure: A longitudinal study
Authors: Krause Elizabeth D. , Kaltman Stacey , Goodman Lisa A. , Dutton Mary Ann 
Published: February 2008

AbstractThe impact of avoidant coping on level of PTSD symptoms over 1 year was examined among 262 women exposed to intimate partner violence (IPV) within the past month. Covariates included childhood sexual abuse (CSA), IPV severity, perceived and formal social support, and revictimization. Using longitudinal hierarchical multiple regression, avoidant coping was found associated with PTSD symptoms at 1‐year follow‐up, controlling for initial symptoms and covariates. Revictimization also had long‐term consequences beyond Time 1 symptoms. Reducing avoidant coping and increasing survivors' safety may assist in breaking a cycle of problematic coping and psychological distress.
A prospective assessment of auditory startle alterations in rape and physical assault survivors
Authors: Griffin Michael G. 
Published: February 2008

AbstractThis study used a prospective design to investigate startle reactivity following trauma exposure. Startle response was evaluated using loud tones during which measures of eyeblink electromyogram (EMG) and heart rate (HR) were collected. Participants were 40 female sexual or physical assault survivors assessed at 1 month and 6 months postassault. There were no significant differences in startle reactivity between posttraumatic stress disorder (PTSD) and non‐PTSD groups at the initial assessment. However, at 6 months postassault there was a significantly greater EMG and HR response in the PTSD group as well as a significant increase in startle reactivity from 1 month to 6 months postassault. The findings lend support to a sensitization model of trauma reactivity in which startle response develops over time along with PTSD symptoms.
Promoting mental health following the London bombings: A screen and treat approach
Authors: Brewin Chris R. , Scragg Peter , Robertson Mary , Thompson Monica , d'Ardenne Patricia , Ehlers Anke 
Published: February 2008

AbstractFollowing the 2005 London bombings, a novel public health program was instituted to address the mental health needs of survivors. In this article, the authors describe the rationale for the program, characteristics of individuals assessed within the program, and preliminary outcome data. In addition to validated screening instruments and routine service usage data, standardized questionnaire outcome measures were collected. Seventy‐one percent of individuals screened positive for a mental disorder. Of those receiving a more detailed clinical assessment, PTSD was the predominant diagnosis. Preliminary outcome data on 82 patients revealed large effect sizes for treatment comparable to those previously obtained in randomized controlled trials. The program succeeded in its aim of generating many more referrals of affected individuals than came through normal referral channels.
On a factorization of the Schrödinger and Klein–Gordon operators
Authors: Cerejeiras Paula , Kähler Uwe , Kravchenko Vladislav V. 
Published: February 2008

AbstractA general scheme for factorizing second‐order time‐dependent operators of mathematical physics is given, which allows a reduction of corresponding second‐order equations to biquaternionic equations of first order. Examples of application of the proposed scheme are presented for both constant and variable coefficients. Copyright © 2008 John Wiley & Sons, Ltd.
Fully automatic, retrospective enhancement of real‐time acquired cardiac cine MR images using image‐based navigators and respiratory motion‐corrected averaging
Authors: Kellman Peter , Chefd'hotel Christophe , Lorenz Christine H. , Mancini Christine , Arai Andrew E. , McVeigh Elliot R. 
Published: February 2008

AbstractReal‐time imaging may be clinically important in patients with congestive heart failure, arrhythmias, or in pediatric cases. However, real‐time imaging typically has compromised spatial and temporal resolution compared with gated, segmented studies. To combine the best features of both types of imaging, a new method is proposed that uses parallel imaging to improve temporal resolution of real‐time acquired images at the expense of signal‐to‐noise ratio (SNR), but then produces an SNR‐enhanced cine by means of respiratory motion‐corrected averaging of images acquired in real‐time over multiple heartbeats while free‐breathing. The retrospective processing based on image‐based navigators and nonrigid image registration is fully automated. The proposed method was compared with conventional cine images in 21 subjects. The resultant image quality for the proposed method (3.9 ± 0.44) was comparable to the conventional cine (4.2 ± 0.99) on a 5‐point scale (P = not significant [n.s.]). The conventional method exhibited degraded image quality in cases of arrhythmias whereas the proposed method had uniformly good quality. Motion‐corrected averaging of real‐time acquired cardiac images provides a means of attaining high‐quality cine images with many of the benefits of real‐time imaging, such as free‐breathing acquisition and tolerance to arrhythmias. Magn Reson Med, 2007. © 2008 Wiley‐Liss, Inc.