bluuebunny/crossref_metadata_2025 huggingface dataset:
Surrogate‐based superstructure optimization framework
Authors: Henao Carlos A. , Maravelias Christos T.
Published: June 2010

In principle, optimization‐based “superstructure” methods for process synthesis can be more powerful than sequential‐conceptual methods as they account for all complex interactions between design decisions. However, these methods have not been widely adopted because they lead to mixed‐integer nonlinear programs that are hard to solve, especially when realistic unit operation models are used. To address this challenge, we develop a superstructure‐based strategy where complex unit models are replaced with surrogate models built from data generated via commercial process simulators. In developing this strategy, we study aspects such as the systematic design of process unit surrogate models, the generation of simulation data, the selection of the surrogate's structure, and the required model fitting. We also present how these models can be reformulated and incorporated into mathematical programming superstructure formulations. Finally, we discuss the application of the proposed strategy to a number of applications. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Local learning‐based adaptive soft sensor for catalyst activation prediction
Authors: Kadlec Petr , Gabrys Bogdan
Published: June 2010

This work presents an algorithm for the development of adaptive soft sensors. The method is based on the local learning framework, where locally valid models are built and maintained. In this framework, it is possible to model nonlinear relationship between the input and output data by the means of a combination of linear models. The method provides the possibility to perform adaptation at two levels: (i) recursive adaptation of the local models and (ii) the adaptation of the combination weights. The dataset used for evaluation of the algorithm describes a polymerization reactor where the target value is a simulated catalyst activity in the reactor. This dataset is also used to evaluate the performance of the proposed algorithm. The results show that the traditional recursive partial least squares algorithm struggles to deliver accurate predictions. In contrast to this, by exploiting the two‐level adaptation scheme, the proposed algorithm delivers more accurate results. © 2010 American Institute of Chemical Engineers AIChE J, 57, 2011
The hexasiladigermacubane dianion
Authors: Lee Vladimir Ya. , Takanashi Kazunori , Matsuno Tadahiro , Ichinohe Masaaki , Sekiguchi Akira
Published: June 2010

Interaction of the heavy analog of the cyclobutadiene dianion derivative [(t‐Bu2MeSi)4Si3Ge]2−·2K+ with the complexing reagent, [2.2.2]cryptand, results in the formation of the first heteronuclear cubane dianion derivative [(t‐Bu2MeSi)6Si6Ge2]2−·2K+, in which both negative charges are exclusively localized at the diagonal Ge atoms. The structure of the title compound was determined by X‐ray crystallography. Copyright © 2010 John Wiley & Sons, Ltd.
Aldehyde functionalized cellulose support for hydrogels
Authors: Wang Yuhong , Hsieh You‐Lo
Published: June 2010

Activated cellulose carrying aldehyde (CHO) and acylchloride (COCl) reactive sites was created by reacting cellulose with dialdehydes, i.e., polyethylene glycol (PEG) diacylchloride and glutaraldehyde (GA), to yield Cell‐PEG‐COCl and Cell‐CHO, respectively. Cellulose fibers and microcrystalline cellulose were readily esterified by PEG diacylchloride to form Cell‐PEG‐COCl to reach as high as 0.24 to 0.37 mmol aceylchloride per gram cellulose, respectively. The generation of free COOH from PEG diacylchloride reactions was optimized at the lower COCl/OH ratio, where the tendency to half‐ester formation was more prevalent than to diesters. Reactions with 8 and 16% GA, generated 0.83 to 1.26 μmol free aldehyde per gram of cellulose, respectively. The reactivity of the aldehyde groups toward poly(vinyl alcohol) (PVA) hydroxyl was robust, generating cellulose fiber supported PVA hydrogels that could swell up to 62 times. These reactions have shown to be highly effective to create aldehyde functionalized cellulose and demonstrated a simple, yet viable way to support PVA hydrogels for superior swelling and improved mechanical stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Electrical and thermal conductivity and tensile and flexural properties of carbon nanotube/polycarbonate resins
Authors: King Julia A. , Via Michael D. , Caspary Jeffrey A. , Jubinski Mary M. , Miskioglu Ibrahim , Mills Owen P. , Bogucki Gregg R.
Published: June 2010

Adding conductive carbon fillers to insulating thermoplastic polymers increases the resulting composite's electrical conductivity. Carbon nanotubes (CNTs) are very effective at increasing composite electrical conductivity at low loading levels without compromising composite tensile and flexural properties. In this study, varying amounts (2–8 wt %) of CNTs were added to polycarbonate (PC) by melt compounding, and the resulting composites were tested for electrical conductivity (1/electrical resistivity), thermal conductivity, and tensile and flexural properties. The percolation threshold was less than 1.4 vol % CNT, likely because of CNTs high aspect ratio (1000). The addition of CNT to PC increased the composite electrical and thermal conductivity and tensile and flexural modulus. The 6 wt % (4.2 vol %) CNT in PC resin had a good combination of properties for electrical conductivity applications. The electrical resistivity and thermal conductivity were 18 Ω‐cm and 0.28 W/m · K, respectively. The tensile modulus, ultimate tensile strength (UTS), and strain at UTS were 2.7 GPa, 56 MPa, and 2.8%, respectively. The flexural modulus, ultimate flexural strength, and strain at ultimate flexural strength were 3.6 GPa, 125 MPa, and 5.5%, respectively. Ductile tensile behavior is noted in pure PC and in samples containing up to 6 wt % CNT. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation, characterization, and property testing of condensation‐type silicone/montmorillonite nanocomposites
Authors: Voulomenou A. , Tarantili P. A.
Published: June 2010

Nanocomposites (NCs) of silicone rubber and organically modified montmorillonite (OMMT) nanoparticles were prepared and characterized. It was shown that OMMT loadings of 2 and 3.5 parts per hundred resin/filler per weight (phr) produced exfoliation or delamination hybrids, whereas at a concentration of 5 phr, the filler seemed to retain its original crystallographic morphology, and the system shifted to an ordinary reinforced elastomer. Fourier transform infrared analysis, differential scanning calorimetry, and thermogravimetric analysis testing were performed for characterization and showed no effect of the nanofiller on the structural parameters of the composites, with the exception of a reduction in the crystallinity. Dynamic mechanical analysis revealed an increase in the glass‐transition temperature (Tg) at OMMT concentrations of 2 and 3.5 phr, whereas at 5 phr, Tg dropped again. Finally, mechanical testing showed an improvement in the tensile strength and stiffness, whereas improved solvent resistance was recorded by swelling experiments in toluene. This experimental study allowed us to explore the range where the OMMT filler produced NCs with silicone elastomers and, furthermore, showed that the incorporation of OMMT into silicone rubber did not introduce any chemical changes but increased the density of crosslinks; this led to a loss of crystallinity, an increase in Tg, and a significant improvement in the tensile properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Surface modification of Aramid fibers with new chemical method for improving interfacial bonding strength with epoxy resin
Authors: Liu Tie‐Min , Zheng Yuan‐Suo , Hu Jie
Published: June 2010

Friedel‐Crafts reaction was elected as the specific chemical approach to modify Aramid fiber surface in this article. After the surface treatment, the interfacial shear strength value of Aramid fiber/Epoxy composites was enhanced by about 50%. The surface elements of Aramid fibers were determined by X‐ray photoelectron spectroscopy, whose results showed that the ratio of Oxygen/Carbon was increased. The crystalline state of Aramid fibers was determined by X‐ray diffraction instrument, and the surface morphological of Aramid fibers was analyzed by Scanning electron microscope. The results indicated that this novel surface treatment approach, which is a suitable way of the batch‐process for Industrialization, not only can improve the interfacial bonding strength of Aramid fibers reinforced Epoxy resin matrix composites remarkably, but also hardly has any negative influence on the intrinsic tensile strength of Aramid fibers. The wettability degree of the fiber surface was enhanced by this new approach too. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of iron carboxylates on the photodegradability of polypropylene. I. Natural weathering studies
Authors: Rajakumar K. , Sarasvathy V. , Thamaraichelvan A. , Chitra R. , Vijayakumar C. T.
Published: June 2010

To enhance the photodegradability of polypropylene (PP), various carboxylates of iron, including ferric caprate (MF03), ferric laurate (MF04), ferric myristate (MF05), ferric palmitate (MF06), and ferric stearate (MF07), were synthesized. Virgin PP was blended with the synthesized prodegradants (0.2%) and blown into films. To study the photodegradation behavior of PP with and without the prodegradants under natural weathering conditions, all of the films were exposed to sunlight according to the procedure of ASTM 1435. All of the weathered films were found to degrade after a certain number of days of exposure; this was found from the steep increases in the carbonyl, hydroperoxide, hydroxyl, lactone, ester, carboxylic acid, and crystallinity indices. At the same time, a sudden decrease in the elongation at break percentages and tensile strength and surface cracks were also observed. PP containing the prodegradants degraded at a faster rate than the virgin material. The time taken for the material to lose half of the elongation at break value was taken as the half‐time, and this was used to determine the effectiveness of the prodegradants. The effectiveness of the prodegradants for the photodegradation of PP was found to be in the following order: MF03 > MF04 > MF05 > MF06 > MF07. With increasing alkyl chain length of the prodegradants, the stability of the alkyl radical increased, whereas the mobility of the radical in the PP matrix decreased. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of pigments on the stability of silicone/montmorillonite prosthetic nanocomposites
Authors: Vasilakos Sozon P. , Tarantili Petroula A.
Published: June 2010

The purpose of this investigation was to evaluate the protection provided to silicone by pigments, such as dry earth pigments. In addition, the effect of nanostructured and organically modified montmorillonite fillers on the overall behavior of reinforced systems was explored. To obtain relevant data and, furthermore, to reveal possible mechanisms of structural changes that could influence silicone stability, pure and reinforced silicon elastomers were mixed with various colorants and studied for their stability to accelerating aging, during the exposure to UV radiation and humidity. A number of tests were run such as, Attenuated Total Reflectance, Fourier Transform Infrared Spectroscopy (ATR‐FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Tensile measurements. Swelling in toluene and color tests were also carried out. The experimental results showed that the UV aging of silicone elastomers results in chain scission and cross‐linking rather than formation of oxygen containing groups. The main conclusion of this work is montmorillonite acts as a significant reinforcement and protects silicone against degradation during exposure to UV irradiation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of the content of silane coupling agent KH‐560 on the properties of LLDPE/magnesium hydroxide composites
Authors: Yang Zhen , Cai Jun , Zhou Chengang , Zhou Dao , Chen Bifeng , Yang Hu , Cheng Rongshi
Published: June 2010

Based on traditional idea of molecular coupling effect, surface modifiers were helpful to improve the performances of inorganic/organic composites. However, it was also widely accepted that the content of surface modifier should be controlled in a suitable range, and more or less modifiers could not reach to optimal properties. The intrinsic reason for this phenomenon was not clear until now. In this article, the influences of the content of surface modifier: silane coupling agent KH‐560, on the final performances of linear low‐density polyethylene (LLDPE)/magnesium hydroxide (MH) composites, have been studied. The performance tests of LLDPE/MH composites, including mechanical properties measurements, thermal oxidative stability analysis, and surface morphology observation, all confirmed that there was an optimal content range of surface modifier. However, further morphology investigation of the modified MH by particle size and particle size distribution analyzer showed that, the particle size and particle size distribution of MH both increased as the content of KH‐560 increased. ATR‐FTIR analysis proved that silane grafting was achieved on the MH particle surface, which not only improved the compatibility between MH and LLDPE for molecular coupling effect, but also caused bigger particle size and wider particle size distribution, which were disadvantageous to improve the performances of the composites. The two opposite effects of the surface modifiers mentioned above affected the final performances of the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of fiber orientation on pore size characteristics of nonwoven structures
Authors: Rawal Amit , Kameswara Rao P. V. , Russell Stephen , Jeganathan Arjun
Published: June 2010

Fiber orientation is a key parameter affecting the geometrical, hydraulic and mechanical properties of nonwoven materials. The effect of fiber orientation on the pore size has been experimentally investigated based on air‐laid, parallel‐laid, and cross‐laid structures following through‐air bonding. It was evident that there is a discernible difference between the mean flow and maximum pore sizes of these nonwoven materials. The influence on pore size was further elucidated by evaluating experimental and theoretical models based on sieving‐percolation pore network theory including a model that incorporates directional parameter to account for the effect of fiber orientation. It was established that good agreement with experimental data can be obtained using such a model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
High dispersion ability of fluorene‐based polyester as a polymer matrix for carbon nanotubes
Authors: Kawasaki Shinichi , Yamada Masahiro , Kobori Kana , Jin Fengzhe , Takata Toshikazu
Published: June 2010

The high compatibility of fluorene‐based polyester (FBP‐HX) as a polymer matrix for multiwalled carbon nanotubes (MWCNTs) is discussed. A low surface resistivity due to the fine dispersion of MWCNTs in FBP‐HX and polycarbonate (PC) is reported. With a solution‐casting method, a percolation threshold with the addition of between 0.5 and 1.0 wt % MWCNTs was observed in the MWCNT/PC and MWCNT/FBP‐HX composites. Because of the coverage of FBP‐HX on the MWCNTs, a higher surface resistivity and a higher percolation ratio of the MWCNT/FBP‐HX composites were achieved compared with the values for the MWCNT/PC composites. In the MWCNT/FBP‐HX composites, MWCNTs covered with FBP‐HX were observed by scanning electronic microscopy. Because of the coverage of FBP‐HX on the MWCNTs, FBP‐HX interfered with the electrical pathway between the MWCNTs. The MWCNTs in FBP‐HX were covered with a 5‐nm layer of FBP‐HX, but the MWCNTs in the MWCNT/PC composites were in their naked state. MWCNT/PC sheets demonstrated the specific Raman absorption of the MWCNTs only with the addition of MWCNTs of 1 wt % or above because of the coverage of the surface of the composite sheet by naked MWCNTs. In contrast, MWCNT/FBP‐HX retained the behavior of the matrix resin until a 3 wt % addition of MWCNTs was reached because of the coverage of MWCNTs by the FBP‐HX resin, induced by its high wettability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Abdominal adiposity in rheumatoid arthritis: Association with cardiometabolic risk factors and disease characteristics
Authors: Giles Jon T. , Allison Matthew , Blumenthal Roger S. , Post Wendy , Gelber Allan C. , Petri Michelle , Tracy Russell , Szklo Moyses , Bathon Joan M.
Published: June 2010

Objective

Abdominal adiposity, especially visceral adiposity, is emerging as a recognized cardiometabolic risk factor. This study was undertaken to investigate how abdominal fat is distributed in rheumatoid arthritis (RA), and its RA‐related determinants.

Methods

Men and women with RA were compared with non‐RA controls from the Multi‐Ethnic Study of Atherosclerosis. Participants underwent anthropometric studies and quantification of visceral and subcutaneous fat areas (VFA and SFA) using abdominal computed tomography.

Results

A total of 131 RA patients were compared with 121 controls. Despite similar body mass index and waist circumference between the RA and control groups, the adjusted mean VFA was 45 cm2 higher (+51%) in male RA patients versus male controls (P = 0.005), but did not significantly differ by RA status in women. The adjusted mean SFA was 119 cm2 higher (+68%) in female RA patients versus female controls (P < 0.001), but did not significantly differ by RA status in men. Elevated VFA (≥75th percentile) was associated with a significantly higher adjusted probability of having an elevated fasting glucose level, hypertension, or meeting the composite definition of the metabolic syndrome in the RA group compared with controls. Within the RA group, rheumatoid factor seropositivity and higher cumulative prednisone exposure were significantly associated with a higher mean adjusted VFA. Higher C‐reactive protein levels and lower Sharp/van der Heijde scores were significantly associated with both VFA and SFA.

Conclusion

The distribution of abdominal fat differs significantly by RA status. Higher VFA in men with RA, and the more potent association of VFA with cardiometabolic risk factors in men and women with RA, may contribute to cardiovascular risk in RA populations.
Knockdown of Fcγ receptor III in an arthritic temporomandibular joint reduces the nociceptive response in rats
Authors: Kramer Phillip R. , Puri Jyoti , Bellinger Larry L.
Published: June 2010

Objective

Fcγ receptor III (FcγRIII; CD16) is a receptor expressed on immune cells that selectively binds IgG molecules. IgG binding results in cellular activation and cytokine release. IgG is an important factor in arthritis and can be found in the arthritic temporomandibular joint (TMJ). We undertook this study to test the hypothesis that a reduction in FcγRIII expression in TMJ tissues would reduce the nociceptive and inflammatory responses in an inflamed joint.

Methods

Small interfering RNA (siRNA), either naked or complexed with linear polyethyleneimine, was injected into the superior joint space of the TMJ in rats. After administration of siRNA the joint was injected with saline or with Freund's complete adjuvant to induce arthritis. Nociceptive responses were quantitated in the rat by measuring the animal's meal duration. FcγRIII expression in the TMJ tissue was assayed by immunocytochemistry or Western blotting. Cleavage of FcγRIII transcript was then assayed by 5′ rapid amplification of complementary DNA ends. Interleukin‐1β (IL‐1β) and IgG content was measured in the TMJ tissue by enzyme‐linked immunosorbent assay.

Results

Injection of FcγRIII siRNA reduced the amount of FcγRIII in the TMJ tissues, and the transcript was cleaved in a manner consistent with an RNA interference mechanism. Moreover, injection of FcγRIII siRNA reduced the nociceptive response of rats with an arthritic TMJ and reduced the amount of the proinflammatory cytokine IL‐1β.

Conclusion

FcγRIII contributes to the pain resulting from inflammatory arthritis of the TMJ, and siRNA has the potential to be an effective treatment for this disorder.
Cecr2 mutations causing exencephaly trigger misregulation of mesenchymal/ectodermal transcription factors
Authors: Fairbridge Nicholas A. , Dawe Christine E. , Niri Farshad H. , Kooistra Megan K. , King‐Jones Kirst , McDermid Heather E.
Published: June 2010

BACKGROUND: Over 200 mouse genes are associated with neural tube defects (NTDs), including Cecr2, the bromodomain‐containing subunit of the CERF chromatin remodeling complex. METHODS: Gene‐trap mutation Cecr2Gt45Bic results in 74% exencephaly (equivalent of human anencephaly) on the BALB/c strain. Gene expression altered during cranial neural tube closure by the Cecr2 mutation was identified through microarray analysis of 11–14 somites stage Cecr2Gt45Bicembryos. RESULTS: Analysis of Affymetrix Mouse 430 2.0 chips detected 60 transcripts up‐regulated and 54 transcripts down‐regulated in the Cecr2Gt45Bic embryos (fold > 1.5, p < 0.05). The Cecr2 transcript was reduced only ∼7‐ to 14‐fold from normal levels, suggesting the Cecr2Gt45Bic is a hypomorphic mutation. We therefore generated a novel Cecr2 null allele (Cecr2
tm1.1Hemc). Resulting mutants displayed a stronger penetrance of exencephaly than Cecr2Gt45Bic in both BALB/c and FVB/N strains, in addition to midline facial clefts and forebrain encephalocele in the FVB/N strain. The Cecr2 transcript is reduced 260‐fold in the Cecr2tm1.1Hemc line. Subsequent qRT‐PCR using Cecr2
tm1.1Hemc mutant heads confirmed downregulation of transcription factors Alx1/Cart1,
Dlx5, Eya1, and Six1. CONCLUSIONS: As both Alx1/Cart1 and Dlx5 mouse mutations result in exencephaly, we hypothesize that changes in expression of these mesenchymal/ectodermal transcription factors may contribute to NTDs associated with Cecr2. Birth Defects Research (Part A), 2010. © 2010 Wiley‐Liss, Inc.
Challenges to multiple testing in clinical trials
Authors: James Hung H. M. , Wang Sue‐Jane
Published: June 2010

Multiple testing problems are complex in evaluating statistical evidence in pivotal clinical trials for regulatory applications. However, a common practice is to employ a general and rather simple multiple comparison procedure to handle the problems. Applying multiple comparison adjustments is to ensure proper control of type I error rates. However, in many practices, the emphasis of the type I error rate control often leads to a choice of a statistically valid multiple test procedure but the common sense is overlooked. The challenges begin with confusions in defining a relevant family of hypotheses for which the type I error rates need to be properly controlled. Multiple testing problems are in a wide variety, ranging from testing multiple doses and endpoints jointly, composite endpoint, non‐inferiority and superiority, to studying time of onset of a treatment effect, and searching for minimum effective dose or a patient subgroup in which the treatment effect lies. To select a valid and sensible multiple test procedure, the first step should be to tailor the selection to the study questions and to the ultimate clinical decision tree. Then evaluation of statistical power performance should come in to play in the next step to fine tune the selected procedure.
Membrane binding and perturbation studies of the antimicrobial peptides caerin, citropin, and maculatin
Authors: Brian Chia C. S. , Gong Yujing , Bowie John H. , Zuegg Johannes , Cooper Matthew A.
Published: June 2010

Citropin 1.1, maculatin 1.1, and caerin 1.1 are short antibacterial cationic peptides from the skin glands of the Australian tree frog Litoria species. Several analogues have been synthesized to give a better insight into the relationship between the structure of the peptides and their antibacterial and haemolytic activity. Binding studies using a surface plasmon resonance (SPR) biosensor together with a vesicle‐capture sensor chip have been used to investigate selectivity of the peptides and their analogues for 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphoglycerol (DMPG) and 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine (DMPC) vesicles, as well as for vesicles made from lipid extracts from Escherichia coli and bovine brain. Data obtained for membrane selectivity using natural lipid extracts show better correlation with minimum inhibitory concentration (MIC) values against Gram‐positive bacteria and haemolytic activity than that obtained using synthetic DMPG and DMPC. Electron microscopy and membrane leakage studies using Gram‐positive bacteria gave further insight into the membrane disruption properties of the peptides. For maculatin 1.1, it was found that the central proline residue, which is responsible for a bend in the α‐helical structure, is essential not only for the antibacterial activity but also for binding, and perturbation of membranes. The caerin analogues showed only small variations in their MIC values and membrane binding. In contrast, for citropin 1.1, the analogue replacing the aspartate with a lysine showed the lowest MIC against Gram‐positive bacteria and best membrane binding to E. coli lipid extracts, coinciding with an increased hydrophobic moment of the peptide. These data give further insight into these antimicrobial natural products, toward the development and evaluation of these and other analogues as potential antibiotics. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 96:147–157, 2011.
Continuous scalable blood filtration device using inertial microfluidics
Authors: Mach Albert J. , Di Carlo Dino
Published: June 2010

Cell separation is broadly useful for applications in clinical diagnostics, biological research, and potentially regenerative medicine. Recent attention has been paid to label‐free size‐based techniques that may avoid the costs or clogging issues associated with centrifugation and mechanical filtration. We present for the first time a massively parallel microfluidic device that passively separates pathogenic bacteria cells from diluted blood with macroscale performance. The device was designed to process large sample volumes in a high‐throughput, continuous manner using 40 single microchannels placed in a radial array with one inlet and two rings of outlets. Each single channel consists of a short focusing, gradual expansion and collection region and uses unique differential transit times due to size‐dependent inertial lift forces as a method of cell separation. The gradual channel expansion region is shown to manipulate cell equilibrium positions close to the microchannel walls, critical for higher efficiency collection. We demonstrate >80% removal of pathogenic bacteria from blood after two passes of the single channel system. The massively parallel device can process 240 mL/h with a throughput of 400 million cells/min. We expect that this parallelizable, robust, and label‐free approach would be useful for filtration of blood as well as for other cell separation and concentration applications from large volume samples. Biotechnol. Bioeng. 2010;107: 302–311. © 2010 Wiley Periodicals, Inc.
Design of cellular porous biomaterials for wall shear stress criterion
Authors: Chen Yuhang , Zhou Shiwei , Cadman Joseph , Li Qing
Published: June 2010

The microfluidic environment provided by implanted prostheses has a decisive influence on the viability, proliferation and differentiation of cells. In bone tissue engineering, for instance, experiments have confirmed that a certain level of wall shear stress (WSS) is more advantageous to osteoblastic differentiation. This paper proposes a level‐set‐based topology optimization method to regulate fluidic WSS distribution for design of cellular biomaterials. The topological boundary of fluid phase is represented by a level‐set model embedded in a higher‐dimensional scalar function. WSS is determined by the computational fluid dynamics analysis in the scale of cellular base cells. To achieve a uniform WSS distribution at the solid–fluid interface, the difference between local and target WSS is taken as the design criterion, which determines the speed of the boundary evolution in the level‐set model. The examples demonstrate the effectiveness of the presented method and exhibit a considerable potential in the design optimization and fabrication of new prosthetic cellular materials for bioengineering applications. Biotechnol. Bioeng. 2010;107:737–746. © 2010 Wiley Periodicals, Inc.
Efficient phase separation and product recovery in organic‐aqueous bioprocessing using supercritical carbon dioxide
Authors: Brandenbusch Christoph , Bühler Bruno , Hoffmann Philip , Sadowski Gabriele , Schmid Andreas
Published: June 2010

Biphasic hydrocarbon functionalizations catalyzed by recombinant microorganisms have been shown to be one of the most promising approaches for replacing common chemical synthesis routes on an industrial scale. However, the formation of stable emulsions complicates downstream processing, especially phase separation. This fact has turned out to be a major hurdle for industrial implementation. To overcome this limitation, we used supercritical carbon dioxide (scCO2) for both phase separation and product purification. The stable emulsion, originating from a stereospecific epoxidation of styrene to (S)‐styrene oxide, a reaction catalyzed by recombinant Escherichia coli, could be destabilized efficiently and irreversibly, enabling complete phase separation within minutes. By further use of scCO2 as extraction agent, the product (S)‐styrene oxide could be obtained with a purity of 81% (w/w) in one single extraction step. By combining phase separation and product purification using scCO2, the number of necessary workup steps can be reduced to one. This efficient and easy to use technique is generally applicable for the workup of biphasic biocatalytic hydrocarbon functionalizations and enables a cost effective downstream processing even on a large scale. Biotechnol. Bioeng. 2010;107:642–651. © 2010 Wiley Periodicals, Inc.
Three‐dimensional culture systems for the expansion of pluripotent embryonic stem cells
Authors: Storm Michael P. , Orchard Craig B. , Bone Heather K. , Chaudhuri Julian B. , Welham Melanie J.
Published: June 2010

Mouse embryonic stem cell (ESC) lines, and more recently human ESC lines, have become valuable tools for studying early mammalian development. Increasing interest in ESCs and their differentiated progeny in drug discovery and as potential therapeutic agents has highlighted the fact that current two‐dimensional (2D) static culturing techniques are inadequate for large‐scale production. The culture of mammalian cells in three‐dimensional (3D) agitated systems has been shown to overcome many of the restrictions of 2D and is therefore likely to be effective for ESC proliferation. Using murine ESCs as our initial model, we investigated the effectiveness of different 3D culture environments for the expansion of pluripotent ESCs. Solohill Collagen, Solohill FACT, and Cultispher‐S microcarriers were employed and used in conjunction with stirred bioreactors. Initial seeding parameters, including cell number and agitation conditions, were found to be critical in promoting attachment to microcarriers and minimizing the size of aggregates formed. While all microcarriers supported the growth of undifferentiated mESCs, Cultispher‐S out‐performed the Solohill microcarriers. When cultured for successive passages on Cultispher‐S microcarriers, mESCs maintained their pluripotency, demonstrated by self‐renewal, expression of pluripotency markers and the ability to undergo multi‐lineage differentiation. When these optimized conditions were applied to unweaned human ESCs, Cultispher‐S microcarriers supported the growth of hESCs that retained expression of pluripotency markers including SSEA4, Tra‐1–60, NANOG, and OCT‐4. Our study highlights the importance of optimization of initial seeding parameters and provides proof‐of‐concept data demonstrating the utility of microcarriers and bioreactors for the expansion of hESCs. Biotechnol. Bioeng. 2010;107:683–695. © 2010 Wiley Periodicals, Inc.
Stoichiometric model and metabolic flux analysis for Leptospirillum ferrooxidans
Authors: Merino M.P. , Andrews B.A. , Asenjo J.A.
Published: June 2010

A metabolic model for Leptospirillum ferrooxidans was developed based on the genomic information of an analogous iron oxidizing bacteria and on the pathways of ferrous iron oxidation, nitrogen and CO2 assimilation based on experimental evidence for L. ferrooxidans found in the literature. From this metabolic reconstruction, a stoichiometric model was built, which includes 86 reactions describing the main catabolic and anabolic aspects of its metabolism. The model obtained has 2 degrees of freedom, so two external fluxes were estimated to achieve a determined and observable system. By using the external oxygen consumption rate and the generation flux biomass as input data, a metabolic flux map with a distribution of internal fluxes was obtained. The results obtained were verified with experimental data from the literature, achieving a very good prediction of the metabolic behavior of this bacterium at steady state. Biotechnol. Bioeng. 2010;107:696–706. © 2010 Wiley Periodicals, Inc.
Financial, ecological and managerial impacts of emission trading schemes: the case of Lufthansa
Authors: Vespermann Jan , Wittmer Andreas
Published: June 2010

Commencing in 2012, emissions from flights departing from or arriving at airports within the European Union (EU) will be covered under the EU emissions trading scheme (ETS). This research analyzes the financial and ecological impacts of the ETS for the Lufthansa Group using a simulation model built on the now‐fixed system design. The results show that while ecological impacts are modest in the first years after introduction, the ETS will result in much higher emission reductions in the medium and long term. These ecological benefits come at the expense of increased financial impacts. This paper argues that the ETS will have a variety of managerial implications at the company level in fields such as environmental monitoring, financial risk management and marketing. Copyright © 2010 John Wiley & Sons, Ltd and ERP Environment.
Miniaturized fluid array for high‐throughput protein expression
Authors: Khnouf Ruba , Olivero Daniel , Jin Shouguang , Fan Z. Hugh
Published: June 2010

We describe a miniaturized fluid array device for high‐throughput cell‐free protein synthesis (CFPS), aiming to match the throughput and scale of gene discovery. Current practice of using E. coli cells for production of recombinant proteins is difficult and cost‐prohibitive to implement in a high‐throughput format. As more and more new genes are being identified, there is a considerable need to have high‐throughput methods to produce a large number of proteins for studying structures and functions of the corresponding genes. The device consists of 96 units and each unit is for expression of one protein; thus up to 96 proteins can be produced simultaneously. The function of the fluid array was demonstrated by expression of a variety of proteins, with more than two orders of magnitude reduction in reagent consumption compared with a commercially available CFPS instrument. The protein expression yield in the device was up to 87 times higher for β‐glucoronidase than that in a conventional microplate. The concentration of β‐galactosidase expressed in the device was determined at 5.5 μg/μL. The feasibility of using the device for drug screening was demonstrated by measuring the inhibitory effects of mock drug compounds on synthesized β‐lactamase without the need for harvesting proteins, which enabled us to reduce the analysis time from days to hours. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Control of dissolved oxygen concentration using neural network in a batch bioreactor
Authors: Mete Tufan , Ozkan Gulay , Hapoglu Hale , Alpbaz Mustafa
Published: June 2010

Artificial neural networks (ANN) have been utilized for many chemical applications because of their ability to learn system features. This paper presents the use of feedforward neural networks for dynamic modelling and dissolved oxygen (DO) control of a batch yeast fermentation. The ARMAX model of this nonlinear process is also presented. Model verification is tested by using experimental data. Different ANNs are trained using the backpropagation learning algorithm. The resulting ANNs are introduced in a Model Predictive Control (MPC) scheme to test the control performance of the structure. At system, output variable that is DO concentration and adjusting variable that is air flow rate are chosen. The robustness of this control structure is studied in the case of setpoint changes. Results obtained with NN‐MPC is also presented and compared with those obtained with Nonlinear Auto Regressive Moving Average (NARMA‐L2) control strategy. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 619–628, 2012
An educational tool for fundamental DC–DC converter circuits and active power factor correction applications
Authors: Kayisli Korhan , Tuncer Servet , Poyraz Mustafa
Published: June 2010

Computer‐aided education has become popular thanks to its flexible and useful structure in classroom environment. In this study, a computer‐based educational tool for DC–DC converters and its active power factor correction (PFC) applications are presented for effective education of these circuits at power electronics courses and reinforcement of the theoretical instruction given at these courses. Firstly, simulations were generated by MATLAB/Simulink toolbox. After then, graphical user interfaces (GUIs) were designed for visual approach to specifying all input and output parameters. The results of the educational tool developed are illustrated with screenshots and graphics. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 113–134, 2013
Unusual Photoinduced Electron Transfer from a Zinc Porphyrin to a Tetrapyridyl Free‐Base Porphyrin in a Noncovalent Multiporphyrin Array
Authors: Ventura Barbara , Flamigni Lucia , Beyler Maryline , Heitz Valérie , Sauvage Jean‐Pierre
Published: June 2010

Excitation of the peripheral Zn porphyrin units in a noncovalent five‐porphyrin array, formed by gable‐like zinc(II) bisporphyrins and a central free‐base meso‐tetrakis(4‐pyridyl)porphyrin in a 2:1 ratio, (ZnP2)2⋅ (TPyP), does not lead to a quantitative sensitization of the luminescence of the free‐base porphyrin acceptor, even though there is an effective energy transfer. Time resolution of the luminescence evidences a quenching of TPyP upon sensitization by the peripheral ZnP2. The time evolution of the TPyP fluorescence in the complex can be described by a bi‐exponential fitting with a major component of 180 ps and a minor one of 5 ns, compared to an isolated TPyP lifetime of 9.4 ns. The two quenched lifetimes are shown to be correlated to the presence of 2:1 and 1:1 complexes, respectively. No quenching of TPyP fluorescence occurs in (ZnP2)2⋅(TPyP) at 77 K in a rigid solvent for which only an energy‐transfer process (τ=150±10 ps) from peripheral ZnP2 to the central TPyP is observed. An unusual HOMO–HOMO electron‐transfer reaction from ZnP2 to the excited TPyP units, responsible for the observed phenomena, is detected. The resulting charge‐separated state, (ZnP2)+2⋅(TPyP)− is found to recombine to the ground state with a lifetime of 11 ns.
Polyoxopalladates Encapsulating Yttrium and Lanthanide Ions, [XIIIPdII12(AsPh)8O32]5− (X=Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)
Authors: Barsukova Maria , Izarova Natalya V. , Biboum Rosa Ngo , Keita Bineta , Nadjo Louis , Ramachandran Vasanth , Dalal Naresh S. , Antonova Nadya S. , Carbó Jorge J. , Poblet Josep M. , Kortz Ulrich
Published: June 2010

A series of novel yttrium‐ and lanthanide‐containing heteropolyoxopalladates have been prepared and isolated as hydrated sodium salts, Na5[XIIIPdII12(AsPh)8O32]⋅y H2O (X=Y (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7), Dy (8), Ho (9), Er (10), Tm (11), Yb (12), Lu (13); y=15–27). The polyanions [XIIIPdII12(AsPh)8O32]5− consist of a cuboid framework of twelve PdII ions with eight phenylarsonate heterogroups located at the vertices and a central guest ion X. The compounds 1–13 have been prepared in a simple one‐pot self‐assembly reaction of Pd(CH3COO)2, phenylarsonic acid and the respective salt of the element X in 0.5 M aqueous sodium acetate solution (pH 6.9), and characterized in the solid state by single‐crystal X‐ray diffraction, elemental and thermogravimetric (TGA) analyses, and IR spectroscopy. It was demonstrated that small, medium, and also large lanthanide ions can be incorporated in the center of the novel heteropolypalladate [XIIIPdII12(AsPh)8O32]5−. The LnO bond lengths follow the expected trend decreasing from left to right in the lanthanide series. This indicates that the {PdII12O32} shell can adjust to the coordination requirements of the encapsulated guest cation. Compounds 3 and 5 were selected for electrochemical studies. Their cyclic voltammetry in a lithium acetate buffer at pH 5.9 showed a Pd0 deposition process on the glassy carbon electrode surface. Coulometry indicated that all PdII centers were reduced to Pd0. The film was stable and could be taken out of the deposition medium and characterized in pure pH 5.9 buffer. Magnetic susceptibility and EPR measurements were carried out on 5 and 6. The former was confirmed to be diamagnetic and the latter strongly paramagnetic with a S=7/2 ground state. DFT calculations for some of the polyoxometalates have been also performed.
ChemInform Abstract: Kinetics and Products of Nitrotoluene Oxidation with Ozone in Acetic Acid.
Authors: GALSTYAN A. G. , GALSTYAN G. A. , TYUPALO N. F.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Asymmetric Reactions Catalyzed by Chiral Metal Complexes. Part 83. Enantioselective Allylic Substitutions Using Ketene Silyl Acetals Catalyzed by a Palladium—Chiral Amidine Complex.
Authors: SAITOH A. , ACHIWA K. , MORIMOTO T.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Asymmetric Kharasch Reaction: Catalytic Enantioselective Allylic Oxidation of Olefins Using Chiral Pyridine Bis(diphenyloxazoline)‐Copper Complexes and tert‐Butyl Perbenzoate.
Authors: SEKAR G. , DATTAGUPTA A. , SINGH V. K.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Stereoselective Conjugate Addition Reactions of α,β‐Unsaturated tert‐Butyl Esters with Aryllithium Reagents.
Authors: FREY L. F. , TILLYER R. D. , CAILLE A.‐S. , TSCHAEN D. M. , DOLLING U. H. , GRABOWSKI E. J. J. , REIDER P. J.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Microwave‐Promoted Lipase‐Catalyzed Reactions.
Authors: LIN G. , LIN W.‐Y.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Aromatic Nucleophilic Substitution in Perfluoro‐1,3,5,7‐tetrahydrobenzo[1,2‐c:4,5‐c′]difuran.
Authors: PLENKIEWICZ H. , DMOWSKI W.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Simultaneous Coordination and Double Activation Phenomena of Carbonyl and Epoxy Oxygens by Bis‐titanium Reagent as a Bidentate Lewis Acid Catalyst.
Authors: ASAO N. , KII S. , HANAWA H. , MARUOKA K.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Conversion of 2‐Methylthio‐4‐trifluoroacetyl‐5,6‐dihydro‐4H‐1,3,4‐thiadiazines into α,β‐Unsaturated Esters via Carbanion‐Induced Ring Opening and Desulfurization.
Authors: SHIMADA K. , OTAKI A. , YANAKAWA M. , MABUCHI S. , YAMAKADO N. , SHIMOGUCHI T. , TAKIKAWA Y.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Cycloreductions via Alkylpalladium Intermediates: Substrate Dependent Cyclopropanations of Palladium Catalyzed Enediyne Cyclizations.
Authors: OH C. H. , KANG J. H. , RHIM C. Y. , KIM J. H.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Lead Tetraacetate Mediated “One‐Pot” Multistage Transformations on Selected Unsaturated 1,2‐Diols: The Wieland—Miescher Series.
Authors: ARSENIYADIS S. , BRONDI‐ALVES R. , QUILEZ DEL MORAL J. , YASHUNSKY D. V. , POTIER P.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Phototrifluoromethylsulfenylation of Phenylcyclopropane.
Authors: MUNAVALLI S. , ROSSMAN D. I. , ROHRBAUGH D. K. , DURST H. D.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: New Intramolecular α‐Arylation Strategy of Ketones by the Reaction of Silyl Enol Ethers to Photosensitized Electron Transfer Generated Arene Radical Cations: Construction of Benzannulated and Benzospiroannulated Compounds.
Authors: PANDEY G. , KARTHIKEYAN M. , MURUGAN A.
Published: June 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.