bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of a slurry‐bubble column reactor for Fischer‐Tropsch synthesis using single‐event microkinetics
Authors: Lozano‐Blanco Gisela , Thybaut Joris W. , Surla Karine , Galtier Pierre , Marin Guy B. 
Published: June 2009

AbstractA single‐event microkinetic model for Fischer‐Tropsch synthesis including the water‐gas shift reaction has been implemented in a one‐dimensional, two‐bubble class, heterogeneous model with axial effective diffusion to study the performance of a commercial slurry bubble column reactor. Mass balance equations are solved for every species in the reaction network in the large bubbles, small bubbles, and slurry phase, whereas the energy balance is applied to the slurry phase. The catalyst concentration profile is described by a sedimentation‐dispersion model. The combination of microkinetics that generate net production rates for the individual reaction products and hydrodynamics allows describing detailed concentration profiles along the reactor axis as a function of operating conditions and design parameters. As example, the effects of catalyst loading, syngas feed flow rate, inlet temperature, or hydrogen to carbon monoxide inlet ratio on the individual hydrocarbons are investigated. To our knowledge, no reactor model in literature is able to describe detailed compositions at the level described by the reactor model developed in this work. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Scheduling multistage batch plants with sequence‐dependent changeovers
Authors: Castro Pedro M. , Novais Augusto Q. 
Published: June 2009

AbstractThis article deals with the optimal short‐term scheduling of multistage batch plants with parallel units and sequence‐dependent changeovers, together with the optimal selection of the number and size of batches to be produced. A new resource‐task network‐based, multiple time‐grid continuous‐time formulation is proposed that explicitly considers a virtual, shared, intermediate storage unit per stage to keep track of material transfer between processing units belonging to consecutive stages of production. Adequate material transfer is implicitly ensured through mass balances and timing constraints relating the times of event points of dissimilar grids. The new formulation is compared with a conceptually different approach from another research group. The results for several example problems show that the new formulation is tighter, typically requiring fewer event points to find the global optimal solution, and is significantly more efficient computationally. The results also show that for single batch problems other approaches are preferable. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Discrete element simulation of free flowing grains in a four‐bladed mixer
Authors: Remy Brenda , Khinast Johannes G. , Glasser Benjamin J. 
Published: June 2009

AbstractNumerical simulations of granular flow in a cylindrical vessel agitated by a four‐blade impeller were performed using the discrete element method. Velocity, density, and stress profiles within the mixer displayed a periodic behavior with a fluctuation frequency equal to that of the blade rotation. Blade orientation was found to affect flow patterns and mixing kinetics. For an obtuse blade pitch orientation, a three‐dimensional recirculation zone develops in‐front of the blade due to formation of heaps where the blades are present. This flow pattern promotes vertical and radial mixing. No recirculation zone was observed when the blade orientation was changed to an acute blade pitch. The system's frictional characteristics are shown to strongly influence the granular behavior within the mixer. At low friction coefficients, the 3‐D recirculation in front of the obtuse blade is not present reducing convective mixing. Higher friction coefficients lead to an increase in granular temperature which is associated with an increase in diffusive mixing. Normal and shear stresses were found to vary with mixer height with maximum values near the bottom plate. Additionally, a strong dependence between the magnitude of the shear stresses and the friction coefficient of the particles was found. The stress tensor characteristics indicate that the granular flow in our simulations occurs in the quasi‐static regime. At the same time, the averaged pressure was found to vary linearly with bed height and could be predicted by a simple hydrostatic approximation. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Oscillating migration and the epidemics of silicosis, tuberculosis, and HIV infection in South African gold miners
Authors: Rees David , Murray Jill , Nelson Gill , Sonnenberg Pam 
Published: June 2009

AbstractBackgroundHundreds of thousands of men from rural areas of South Africa and neighboring countries have come to seek work in the gold mines. They are not immigrants in the usual sense as they work for periods in the mines, go home, and then return. This is termed oscillating or circular migration. Today we have serious interrelated epidemics of silicosis, tuberculosis, and HIV infection in the gold mining industry.MethodsThis article discusses the role of oscillating migration in fuelling these epidemics, by examining the historical, political, social, and economic contexts of these diseases.ResultsThe impact of silicosis, tuberculosis, and HIV infection extends beyond individual miners to their families and communities.ConclusionFailure to control dust and tuberculosis has resulted in serious consequences decades later. The economic and political migrant labor system provided the foundations for the epidemics seen in southern Africa today. Am. J. Ind. Med. 53:398–404, 2010. © 2009 Wiley‐Liss, Inc.
Copeptin: A novel, independent prognostic marker in patients with ischemic stroke
Authors: Katan Mira , Fluri Felix , Morgenthaler Nils G. , Schuetz Philipp , Zweifel Christian , Bingisser Roland , Müller Klaus , Meckel Stephan , Gass Achim , Kappos Ludwig , Steck Andreas J. , Engelter Stefan T. , Müller Beat , Christ‐Crain Mirjam 
Published: June 2009

AbstractObjectiveEarly prediction of outcome in patients with ischemic stroke is important. Vasopressin is a stress hormone. Its production rate is mirrored in circulating levels of copeptin, a fragment of provasopressin. We evaluated the prognostic value of copeptin in acute stroke patients.MethodsIn a prospective observational study, copeptin was measured using a new sandwich immunoassay on admission in plasma of 362 consecutive patients with an acute ischemic stroke. The prognostic value of copeptin to predict the functional outcome (defined as a modified Rankin Scale score of ≤2 or ≥3), mortality within 90 days, was compared with the National Institutes of Health Stroke Scale score and with other known outcome predictors.ResultsPatients with an unfavorable outcomes and nonsurvivors had significantly increased copeptin levels on admission (p <0.0001 and p <0.0001). Receiver operating characteristics to predict functional outcome and mortality demonstrated areas under the curve of copeptin of 0.73 (95% confidence interval [CI], 0.67–0.78) and 0.82 (95% CI, 0.76–0.89), which was comparable with the National Institutes of Health Stroke Scale score but superior to C‐reactive protein and glucose (p <0.01). In multivariate logistic regression analysis, copeptin was an independent predictor of functional outcome and mortality, and improved the prognostic accuracy of the National Institutes of Health Stroke Scale to predict functional outcome (combined areas under the curve, 0.79; 95% CI, 0.74–0.84; p <0.01) and mortality (combined areas under the curve, 0.89; 95% CI, 0.84–0.94; p <0.01).InterpretationCopeptin is a novel, independent prognostic marker improving currently used risk stratification of stroke patients. Ann Neurol 2009;66:799–808
Chronic inflammatory demyelinating polyneuropathy sera inhibit axonal growth of mouse dorsal root ganglion neurons by activation of rho‐kinase
Authors: Taniguchi Junko , Sawai Setsu , Mori Masahiro , Kubo Takekazu , Kanai Kazuaki , Misawa Sonoko , Isose Sagiri , Yamashita Toshihide , Kuwabara Satoshi 
Published: June 2009

AbstractClinical course and prognosis are variable among patients with chronic inflammatory demyelinating polyneuropathy (CIDP), whereas the extent of axonal degeneration is the major prognostic factor. We studied the effects of sera from CIDP patients on axonal growth in cultured mouse dorsal root ganglion neurons. Compared with control sera, CIDP sera prominently suppressed axonal outgrowth of dorsal root ganglion neurons and shortened axonal length. The inhibitory activity was abolished by adding Y27632, a Rho‐kinase inhibitor. These findings suggest that CIDP sera inhibit axonal elongation by Rho‐kinase activation, and some serum factors may be responsible for development of axonal degeneration in CIDP. Ann Neurol 2009;66:694–697
Perfusion computed tomography in the acute phase of mild head injury: Regional dysfunction and prognostic value
Authors: Metting Zwany , Rödiger Lars A. , Stewart Roy E. , Oudkerk Matthijs , De Keyser Jacques , van der Naalt Joukje 
Published: June 2009

AbstractObjectiveTraumatic brain injury is a major cause of disability and death. Most patients sustain a mild head injury with a subgroup that experiences disabling symptoms interfering with return to work. Brain imaging in the acute phase is not predictive of outcome, as 20% of noncontrast computed tomographic (CT) scans on admission is normal in patients with a suboptimal outcome. The aim of this study was to perform perfusion CT imaging in the acute phase of mild head injury in patients without intracranial abnormalities on the noncontrast CT, to assess whether these patients had cerebral perfusion abnormalities. Furthermore, the relation between perfusion CT parameters and severity of head injury and outcome was evaluated.MethodsIn patients with mild head injury and normal noncontrast CT, perfusion CT was performed directly after admission. The perfusion data were compared with data of 25 healthy control subjects. Outcome was determined 6 months after injury with the extended Glasgow Coma Outcome Scale score and return to work.ResultsSeventy‐six patients were included. In patients with a decreased Glasgow Coma Scale score, a significant decrease of cerebral blood flow and cerebral blood volume was detected in the frontal and occipital gray matter. In logistic regression analyses, decreased cerebral blood flow and cerebral blood volume in the frontal lobes predicted worse outcome according to the extended Glasgow Coma Outcome Scale score. CT perfusion parameters did not predict return to work.InterpretationIn the acute phase of mild head injury, disturbed cerebral perfusion is seen in patients with normal noncontrast CT correlating with severity of injury and outcome. Ann Neurol 2009;66:809–816
Slowed progression in models of huntington disease by adipose stem cell transplantation
Authors: Lee Soon‐Tae , Chu Kon , Jung Keun‐Hwa , Im Woo‐Seok , Park Jeong‐Eun , Lim Hun‐Chang , Won Chong‐Hyun , Shin Seung‐Hyun , Lee Sang Kun , Kim Manho , Roh Jae‐Kyu 
Published: June 2009

AbstractObjectiveAdipose‐derived stem cells (ASCs) are readily accessible and secrete multiple growth factors. Here, we show that ASC transplantation rescues the striatal pathology of Huntington disease (HD) models.MethodsASCs were isolated from human subcutaneous adipose tissue. In a quinolinic acid (QA)‐induced rat model of striatal degeneration, human ASCs (1 million cells) were transplanted into the ipsilateral striatal border immediately after the QA injection. In 60‐day‐old R6/2 mice transgenic for HD, ASCs (0.5 million cells) were transplanted into each bilateral striata. In in vitro experiments, we treated mutant huntingtin gene‐transfected cerebral neurons with ASC‐conditioned media.ResultsIn the QA model, human ASCs reduced apomorphine‐induced rotation behavior, lesion volume, and striatal apoptosis. In R6/2 transgenic mice, transplantation of ASCs improved Rota‐Rod performance and limb clasping, increased survival, attenuated the loss of striatal neurons, and reduced the huntingtin aggregates. ASC‐transplanted R6/2 mice expressed elevated levels of peroxisome proliferator‐activated receptor γ coactivator‐1α (PGC‐1α) and reactive oxygen defense enzymes and showed activation of the Akt/cAMP‐response element‐binding proteins. ASC‐conditioned media decreased the level of N‐terminal fragments of mutant huntingtin and associated apoptosis, and increased PGC‐1α expression.InterpretationCollectively, ASC transplantation slowed striatal degeneration and behavioral deterioration of HD models, possibly via secreted factors. Ann Neurol 2009;66:671–681
Carbon‐nitrogen‐phosphorus removal and biofilm growth characteristics in an integrated wastewater treatment system involving a rotating biological contactor
Authors: Cabije Angelo H. , Agapay Ramelito C. , Tampus May V 
Published: June 2009

AbstractA new rotating biological contactor‐packed media technology (RBC‐PMT) is locally innovated using light polyethylene Amazon screen material as disc media. A single‐stage co‐current fed of this type, which is connected with a series of equalization tanks as an integrated wastewater treatment system (IWWTS), showed good carbon‐nitrogen‐phosphorus (C‐N‐P) removal and unveiled biofilm growth characteristics noteworthy for treating pollutants in wastewater.The equalization tanks approached facultative anaerobic conditions while the RBC‐PMT exhibited a completely aerated system, both with a slightly alkaline pH, whose temperatures are ranging from 21 to 24 °C, and both performed as biological nutrient removal systems. The combined nutrient removal efficiency at high organic loading rate (HOLR) and low organic loading rate (LOLR) showed fair chemical oxygen demand (COD) removal at 65.68 and 67.89%, respectively. Nitrate‐nitrogen removal demonstrated good removal at 79.17% at HOLR and 83.43% at LOLR. There was excellent phosphate‐phosphorus removal determined at 91.64 and 94.35% at high and low OLRs, respectively. This indicates that increasing the organic loading rate decreases the C‐N‐P removal in the IWWTS.Biofilm growth was characterized by the selection and survival of microorganisms present under aerobic environmental conditions in the RBC‐PMT system and their respective metabolism in removing C‐N‐P substrates. Yeasts, coliform bacteria particularly E. coli, Cyanobacteria, and benthic diatoms were dominant microorganisms found upon oil‐immersion microscopy. Protozoans and algae including Chlorococcum, Chlorella, Diatoma, Tribonema, Oscillatoria, Euglena, and other motile rotifiers were also dominantly found in the biofilm samples. Biofilm growth is observed and its average thickness was measured to be 7.71 µm at HOLR and 2.81 µm at LOLR. Thicker biofilm at HOLR has caused the reduced rate of diffusion of the microorganisms and their metabolic products as manifested by the low C‐N‐P removal during HOLR. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Characterization and effect of modified surface on the morphology, structure and function of rabbit bone marrow‐derived mesenchymal stem cells 1
Authors: Song K. D. , Liu K. , Liu T. Q. , Ma X. H. 
Published: June 2009

AbstractThe surface morphologies modified with chitosan and gelatin respectively, the effects on cell spreading, adhesion and distribution of rabbit bone marrow‐derived mesenchymal stem cells (rMSCs) were observed under atomic force microscope (AFM). The structures and morphologies of rMSCs on coverslips were qualitatively and quantitatively assayed under AFM. Thereafter, the growth status and viability of rMSCs on the different coated surfaces were examined under inverted microscope and by Hoechst/PI double staining. The results showed that the surfaces modified with different materials presented different morphologies. The rMSCs adhered to the surfaces modified with 2 mg/ml chitosan and 0.5 mg/ml gelatin solution showed better viabilities than those of other groups, and the latter also presented the optimal cell adhesion, spreading and distribution with clear cellular structure such as cell nucleus, villus and interaction among various rMSCs. It is indicated that the surface modification played an important role on the development of cellular structure and function of rMSCs, and thus provided theoretical guidance to the fabrication and surface modification of embedded biomaterials in further clinical applications. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
The isolation and characterization of lignin of kenaf fiber
Authors: Yan Tingting , Xu Yingqi , Yu Chongwen 
Published: June 2009

AbstractIn this article, milled wood lignin (MWL) was isolated and purified from retted kenaf fiber, the lignin obtained was characterized by elemental analysis, FTIR, 1H‐NMR, and 13C‐NMR spectroscopy. The C9 formula is calculated for kenaf fiber MWL as C9H9.32O3.69(OCH3)1.30. The spectra of FTIR, 1H‐NMR, and 13C‐NMR show the kenaf fiber lignin to be of the G/S type with high proportion of syringyl (S) unit. The numbers of phenolic and aliphatic hydroxyl groups in the kenaf fiber MWL are estimated to be 0.14 and 1.31, respectively, per C9 unit. The OHaliph is 90.3% in total numbers of hydroxyl groups of kenaf fiber MWL, and the OHph is 9.7%. It is evident that the β‐O‐4 structures are mainly linkage in the MWL of kenaf fiber, which contain more erythro stereochemistry type in β‐O‐4 units than thero stereochemistry type. In general, the characteristics of lignin of kenaf fiber are similar to that of hardwood. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Characterization and enzymatic degradation of PEG‐cross‐linked chitosan hydrogel films
Authors: Tanuma Hiroaki , Kiuchi Hiroki , Kai Weihua , Yazawa Koji , Inoue Yoshio 
Published: June 2009

AbstractIn our previous study (Kiuch et al., J Appl Polym Sci 2008, 107, 3823), poly(ethylene glycol) (PEG) cross‐linked chitosan hydrogel films with various PEG to chitosan ratio and PEG molecular weight have been successfully prepared and their thermal, mechanical and swelling properties at acidic pH were studied. These films are potential biodegradable polymeric materials, because their constituents, that is, chitosan and PEG, are well known as biodegradable polymers. In this study, glass transition temperature (Tg), contact angle, swelling behavior at physiological conditions and in vitro enzymatic degradation behavior were investigated for the PEG‐cross‐linked chitosan hydrogel films. These properties of chitosan hydrogel were found to change significantly upon introducing the PEG‐cross‐links. According to differential scanning calorimeter analysis, the Tg value increased with the PEG content in the hydrogel films, indicating the densification of the film by PEG‐crosslinking. The contact angle was decreased with increasing the number of crosslinks, reflecting that introduction of the cross‐linked structure induced the reduction of chitosan ordered structure. The swelling behavior depended on the PEG to chitosan ratio and the cross‐linked structure. The water content was changed with the number of PEG‐crosslinks. The rate of lysozyme‐catalyzed degradation was also influenced by the introduction of PEG‐cross‐linked structure. The surface morphology of the film was observed by the scanning electron microscopy. It was confirmed that the PEG‐cross‐linked chitosan hydrogel film was degraded by lysozyme from its surface area. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Characterization of rubber phase in acrylonitrile–butadiene–styrene polymers
Authors: Zamani A. , Abbasi F. , Agah A. M. 
Published: June 2009

AbstractThe performances of rubber‐toughened polymers like acrylonitrile–butadiene–styrene (ABS) are strongly affected by the type and amount of rubber phase. Characterization of rubber phase is an effective method to predict and control the physical and mechanical behaviors of ABS materials. In this work, different methods have been employed to determine the amount of rubber phase in ABS polymers. The first method was based on thermogravimetry using a particular step degradation of the polymer. In the second method, characteristic absorption bands in the Fourier transform infrared spectra were used to make a calibration curve to determine the rubber content of unknown ABS samples. The third method was based on variation of heat capacity of ABS polymers with increasing the rubber phase content. In the fourth method, a two‐step solvent extraction followed by centrifuging was used to separate the rubber particles of different ABS samples. Separation of hardened rubber particles was used to study the size and size distribution of rubber particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of Novel 2,5‐Disubstituted 1,3,4‐Thiadiazoles for Their Potential Anticonvulsant Activity: Pharmacophoric Model Studies
Authors: Rajak Harish , Deshmukh Ravitas , Aggarwal Navneet , Kashaw Sushil , Kharya Murli Dhar , Mishra Pradeep 
Published: June 2009

AbstractA series of novel N1‐[5‐(4‐substituted phenyl)‐1,3,4‐thiadiazol‐2‐yl]‐N4‐(4‐substituted benzaldehyde)‐semicarbazone 1–12, N1‐[5‐(4‐substituted phenyl)‐1,3,4‐thiadiazol‐2‐yl]‐N4‐[1‐(4‐substituted phenyl)ethanone]‐semicarbazone 13‐16, and N1‐[5‐(4‐substituted phenyl)‐1,3,4‐thiadiazol‐2‐yl]‐N4‐[1‐(4‐substituted phenyl) (phenyl) methanone]‐semicarbazone 17–20 were synthesized for their anticonvulsant activity. The chemical structures of the compounds were proved by elemental and spectral (IR, 1H‐NMR, 13C‐NMR, and MS) analysis. The anticonvulsant potential of the compounds was investigated using maximal electroshock seizure (MES) and subcutaneous pentylenetrtrazole (scPTZ) models. Compound 19 was found to possess significant anticonvulsant activity in both the models employed for anticonvulsant evaluation. Compounds 8, 13, 15, and 16 also demonstrated a marked anticonvulsant property. The results of the present study validated that the pharmacophore model with four binding sites is essential for anticonvulsant activity. The efforts were also made to establish structure‐activity relationships among the synthesized compounds.
Sensitivity and specificity of spinal inflammatory lesions assessed by whole‐body magnetic resonance imaging in patients with ankylosing spondylitis or recent‐onset inflammatory back pain
Authors: Weber Ulrich , Hodler Juerg , Kubik Rahel A. , Rufibach Kaspar , Lambert Robert G. W. , Kissling Rudolf O. , Pfirrmann Christian W. A. , Maksymowych Walter P. 
Published: June 2009

AbstractObjectiveTo determine the diagnostic utility of different spinal inflammatory lesions assessed by whole‐body magnetic resonance imaging (MRI) in patients with ankylosing spondylitis (AS) or with recent‐onset inflammatory back pain (IBP) compared with healthy controls.MethodsWe scanned 35 consecutive patients with AS fulfilling the modified New York criteria, 25 patients with IBP of <24 months' duration (both groups were age ≤45 years and had a Bath Ankylosing Spondylitis Disease Activity Index score ≥4), and 35 healthy age‐ and sex‐matched volunteers using whole‐body MRI STIR sequences of the spine. MRIs were independently assessed in random order by 3 readers blinded to patient identity. Inflammatory spinal lesions were recorded consistent with definitions proposed by the Canada/Denmark International MRI Working Group: vertebral corner inflammatory lesions (CIL) and noncorner inflammatory lesions in central sagittal slices and lateral inflammatory lesions (LIL) in lateral slices. Concordantly scored lesions for the 3 possible reader pairs were used in the analysis of sensitivity, specificity, likelihood ratios (LRs), and areas under the curve for the entire spine and by spinal segment.ResultsDiagnostic utility was optimal when ≥2 CIL were recorded (for patients with AS, values for sensitivity, specificity, and positive LR were 69%, 94%, and 12, respectively, and for patients with IBP were 32%, 96%, and 8, respectively). LIL had high specificity (97%) but low sensitivity (31%). Nine controls had ≥1 CIL, but only 2 controls had >2 CIL.ConclusionDiagnostic utility of STIR MRI for AS is optimal when ≥2 CIL are present. A single CIL can be found in up to 26% of healthy individuals.