bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Facile One‐Pot Synthesis and Enhanced Formic Acid Oxidation of Monodisperse Pd–Cu Nanocatalysts
Authors: Park Kyu‐Hwan , Lee Young Wook , Kang Shin Wook , Han Sang Woo 
Published: April 2011

AbstractHighly monodisperse spherical 3 nm Pd–Cu alloy nanoparticles (NPs) were synthesized in high yield through the coreduction of [Pd(acac)2] (acac=acetylacetonate) and [Cu(acac)2] in nonhydrolytic solutions by using trioctylamine and oleic acid. The relative compositions of Pd and Cu could be tuned by controlling the molar ratios between the metal precursors in the raw solutions. The carbon‐supported Pd–Cu NPs (Pd–Cu/C) were chemically dealloyed by acetic acid washing, which resulted in the formation of porous structures. The prepared Pd–Cu/C catalysts exhibited at least threefold enhancement of Pd mass activities compared with a commercial Pd/C catalyst toward formic acid oxidation in an acidic medium, and also showed outstanding electrocatalytic stabilities. The improved electrocatalytic properties of the Pd–Cu NPs are attributed to the presence of a large number of active sites on their surfaces owing to their small particle sizes and chemically dealloyed porous structures.
Effects of oral curcumin on the pharmacokinetics of intravenous and oral etoposide in rats: possible role of intestinal CYP3A and P‐gp inhibition by curcumin
Authors: Lee Chong‐Ki , Ki Sung‐Hwan , Choi Jun‐Shik 
Published: April 2011

AbstractThis study aimed to investigate the effects of oral curcumin on the pharmacokinetics of intravenous and oral etoposide in rats. Intravenous (6 mg/kg) or oral (2 mg/kg) etoposide was administered to rats in the absence and the presence of oral curcumin (0.4, 2 or 8 mg/kg). The effects of curcumin on the P‐glycoprotein (P‐gp) and CYP3A4 activity was also evaluated. Curcumin inhibited CYP3A4 enzyme activity with a 50% inhibition concentration (IC50) of 2.7 µM. In addition, curcumin (10 µm) significantly enhanced the cellular accumulation of rhodamine‐123 in MCF‐7/ADR cells overexpressing P‐gp. Compared with the control group (given etoposide alone), curcumin (2 or 8 mg/kg) increased significantly the oral bioavailability (AUC and Cmax) of etoposide. Consequently, the extent of absolute oral bioavailability (F) of etoposide with curcumin was significantly enhanced compared with that in the control group. In contrast, curcumin did not affect the pharmacokinetics of etoposide after intravenous administration. Therefore, the enhanced oral bioavailability of etoposide in the presence of curcumin might be due mainly to inhibition of the P‐gp efflux pump in the small intestine and possibly by reduced first‐pass metabolism of etoposide in the small intestine by inhibition of CYP3A activity in rats. The combined use of curcumin may be helpful to improve the F of etoposide in chemotherapeutic applications. Copyright © 2011 John Wiley & Sons, Ltd.
Signatures of co‐translational folding
Authors: Saunders Rhodri , Mann Martin , Deane Charlotte M. 
Published: April 2011

AbstractGlobal and co‐translational protein folding may both occur in vivo, and understanding the relationship between these folding mechanisms is pivotal to our understanding of protein‐structure formation. Within this study, over 1.5 million hydrophobic–polar sequences were classified based on their ability to attain a unique, but not necessarily minimal energy conformation through co‐translational folding. The sequence and structure properties of the sets were then compared to elucidate signatures of co‐translational folding. The strongest signature of co‐translational folding is a reduced number of possible favorable contacts in the amino terminus. There is no evidence of fewer contacts, more local contacts, or less‐compact structures. Co‐translational folding produces a more compact amino‐ than carboxy‐terminal region and an amino‐terminal‐biased set of core residues. In real proteins these signatures are also observed and found most strongly in proteins of the alpha/beta structural class of proteins (SCOP) where 71 % have an amino‐terminal set of core residues. The prominence of co‐translational features in experimentally determined protein structures suggests that the importance of co‐translational folding is currently underestimated.
Amide‐linkage formed between ammonia plasma treated poly(D,L‐lactide acid) scaffolds and bio‐peptides: Enhancement of cell adhesion and osteogenic differentiation in vitro
Authors: Xu Zi‐Xing , Li Tao , Zhong Zhao‐Ming , Zha Ding‐Sheng , Wu Song‐Hui , Liu Fu‐Qiang , Xiao Wen‐De , Jiang Xiao‐Rui , Zhang Xin‐Xin , Chen Jian‐Ting 
Published: April 2011

AbstractThe surface characteristics of scaffolds for bone tissue engineering must support cell adhesion, migration, proliferation, and osteogenic differentiation. In the study, poly(D,L‐lactide acid) (PDLLA) scaffolds were modified by combing ammonia (NH3) plasma pretreatment with Gly‐Arg‐Gly‐Asp‐Ser (GRGDS)‐peptides coupling technologies. The x‐ray photoelectron spectroscopy (XPS) survey spectra showed the peak of N1s at the surface of NH3 plasma pretreated PDLLA, which was further raised after GRGDS conjugation. Furthermore, N1s and C1s in the high‐resolution XPS spectra revealed the presence of CN (imine), CNH (amine), and CONH (amide) groups. The GRGDS conjugation increased amide groups and decreased amine groups in the plasma‐treated PDLLA. Confocal microscope and high performance liquid chromatography verified the anchored peptides after the conjugation process. Bone marrow mesenchymal stem cells were co‐cultured with scaffolds. Fluorescent microscope and scanning electron microscope photographs revealed the best cell adhesion in NH3 plasma pretreated and GRGDS conjugated scaffolds, and the least attachment in unmodified scaffolds. Real‐time PCR demonstrated that expression of osteogenesis‐related genes, such as osteocalcin, alkaline phosphatase, type I collagen, bone morphogenetic protein‐2 and osteopontin, was upregulated in the single NH3 plasma treated and NH3 plasma pretreated scaffolds following GRGDS conjugation. The results show that NH3 plasma treatment promotes the conjugation of GRGDS peptides to the PDLLA scaffolds via the formation of amide linkage, and combination of NH3 plasma treatment and peptides conjugation may enhance the cell adhesion and osteogenic differentiation in the PDLLA scaffolds. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 682–694, 2011.
Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water
Authors: Salvi Anna M. , Moscarelli Pasquale , Satriano Giuseppina , Bochicchio Brigida , Castle James E. 
Published: April 2011

AbstractElastin‐like polypeptides adopt complex supramolecular structures, showing either a hydrophobic or a hydrophilic surface, depending on their surrounding environment and the supporting substrate. The preferred organization is important in many situations ranging from biocompatibility to bio‐function. Here we compare the n‐repeat pentamer LeuGlyGlyValGly (n = 7) with the analogue ValGlyGlyValGly (n = 5), as water suspensions and as deposits on silicon substrates. These sequences contain the repeat XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu) motif belonging to the hydrophobic glycine‐rich domain of elastin and represent a simplified model from which to obtain information on molecular interactions functional to elastin itself. The compounds studied differ only by the presence of the CH2 spacer in the Leu moiety and thus the work was aimed at revealing the influence of this spacer element on self assembly. Both polypeptides were studied under identical conditions, using combined techniques, to identify differences in their conformational states both at molecular (CD, FTIR) and supramolecular (XPS, AFM) levels. By these means, together with a Congo Red spectroscopic assay of β‐sheet formation in water, a clear correlation between amino acid sequences (sequence specificity) and their kinetics and ordering of aggregation has emerged. The novel outcomes of this work are from the supplementary measurements, made to augment the AFM and XPS studies, showing that the significant step in the self assembly of both polypeptides takes place in the liquid phase and from the finding that the substitution of Val by Leu in the first position of the pentapeptide effectively inhibits the formation of amyloidal fibers. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 702–721, 2011.
Characterizing flexible and intrinsically unstructured biological macromolecules by SAS using the Porod‐Debye law
Authors: Rambo Robert P. , Tainer John A. 
Published: April 2011

AbstractUnstructured proteins, RNA or DNA components provide functionally important flexibility that is key to many macromolecular assemblies throughout cell biology. As objective, quantitative experimental measures of flexibility and disorder in solution are limited, small angle scattering (SAS), and in particular small angle X‐ray scattering (SAXS), provides a critical technology to assess macromolecular flexibility as well as shape and assembly. Here, we consider the Porod‐Debye law as a powerful tool for detecting biopolymer flexibility in SAS experiments. We show that the Porod‐Debye region fundamentally describes the nature of the scattering intensity decay by capturing the information needed for distinguishing between folded and flexible particles. Particularly for comparative SAS experiments, application of the law, as described here, can distinguish between discrete conformational changes and localized flexibility relevant to molecular recognition and interaction networks. This approach aids insightful analyses of fully and partly flexible macromolecules that is more robust and conclusive than traditional Kratky analyses. Furthermore, we demonstrate for prototypic SAXS data that the ability to calculate particle density by the Porod‐Debye criteria, as shown here, provides an objective quality assurance parameter that may prove of general use for SAXS modeling and validation. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 559–571, 2011.
Imaging of parastomal hernia using three-dimensional intrastomal ultrasonography
Authors: Gurmu A , Gunnarsson U , Strigård K 
Published: April 2011

Abstract

Background
Parastomal hernia is common in patients with a permanent stoma. At present there is no standard method for imaging a parastomal hernia. The aim of this study was to investigate the value of three-dimensional intrastomal ultrasonography in differentiating between a parastomal hernia and a bulge.

Methods
Twenty patients were divided into four groups according to ultrasonography setting and probe cover. All patients were tested using three different ultrasound probe frequencies (9, 13 and 16 MHz). The intrastomal examination was performed during provocation in both the supine and upright positions, with a protector or water-containing balloon surrounding the probe.

Results
The sharpest images were obtained using the rectal setting with a water-containing balloon surrounding the probe at 9 MHz in supine and erect positions, for evaluation of both fascia and muscle; in some instances even implanted mesh was detectable. When switched to render mode, the pictures improved in sharpness and it was easier to identify anatomical landmarks.

Conclusion
Intrastomal ultrasonography using the rectal setting and a frequency of 9 MHz is a feasible method for imaging a parastomal hernia and differentiating it from an abdominal bulge. The image quality improves when render mode is used.
Safety of hepatic resection in overweight and obese patients with cirrhosis
Authors: Cucchetti A , Cescon M , Ercolani G , Di Gioia P , Peri E , Pinna A D 
Published: April 2011

Abstract

Background
The simultaneous incremental increase in incidence of both obesity and hepatocellular carcinoma (HCC) will soon lead to more overweight and obese patients with cirrhosis needing surgery. At present, little is known about postoperative mortality and morbidity in such patients. This study investigated outcomes after hepatectomy in relation to obesity in a homogeneous cohort of patients with cirrhosis.

Methods
Perioperative data from 235 patients with cirrhosis who had hepatectomy for HCC were related to the presence of normal bodyweight (body mass index (BMI) 18·5–24·9 kg/m2), overweight (BMI 25·0–29·9 kg/m2) and obesity (BMI at least 30 kg/m2). Complications after surgery were graded according to the expanded Accordion Severity Classification of Postoperative Complications (T92).

Results
One hundred and one patients (43·0 per cent) were of normal bodyweight, 88 (37·4 per cent) were overweight and 46 (19·6 per cent) were obese; none was underweight. Overweight and obese groups showed a male preponderance (P = 0·024), and metabolic disorders were frequently the cause of cirrhosis in these patients (P &lt; 0·001 and P = 0·014 for non-B non-C hepatitis and alcoholic cirrhosis respectively). Liver function tests, tumour stage and extent of hepatectomy did not significantly differ between BMI groups. The intraoperative course and postoperative mortality were unaffected by BMI. Overweight and obese patients had significantly more mild respiratory complications (P = 0·044). Severe complications and organ system (including liver) failure were not significantly affected by BMI.

Conclusion
Hepatic resection can be performed safely in overweight and obese patients with cirrhosis, although morbidity is increased in these patients.
Partitioning of amino acids in the aqueous biphasic system containing the water‐miscible ionic liquid 1‐butyl‐3‐methylimidazolium bromide and the water‐structuring salt potassium citrate
Authors: Zafarani‐Moattar Mohammed Taghi , Hamzehzadeh Sholeh 
Published: April 2011

AbstractIn biotechnology, extraction by means of aqueous biphasic systems (ABS) is known as a promising tool for the recovery and purification of bio‐molecules. Over the past decade, the increasing emphasis on cleaner and environmentally benign extraction procedures has led to enhanced interest in the ABS containing ionic liquids (ILs)—a new class of non‐volatile alternative solvents. ABS composed of the hydrophilic IL {1‐butyl‐3‐methylimidazolium bromide ([C4mim]Br)} and potassium citrate—which is easily degraded—represents a clean media to green separation of bio‐molecules. In this regard, here, the extraction capability of this ABS was evaluated through its application to the extraction of some amino acids. To gain an insight into the driving forces of amino acid partitioning in the studied IL‐based ABS, the distribution of five model amino acids (L‐tryptophan, L‐phenylalanine, L‐tyrosine, L‐leucine, and L‐valine) at different aqueous medium pH values and different phase compositions was investigated. The studies indicated that hydrophobic interactions were the main driving force, although electrostatic interactions and salting‐out effects were also important for the transfer of the amino acids. Moreover, based on the statistical analysis of the driving forces of amino acid partitioning in the studied IL‐based ABS, a model was established to describe the partition coefficient of three model amino acids, L‐tryptophan, L‐phenylalanine, and L‐valine, and employed to predict the partition coefficient of two other model amino acids, L‐tyrosine and L‐leucine. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Dual perfluorocarbon method to noninvasively monitor dissolved oxygen concentration in tissue engineered constructs in vitro and in vivo
Authors: Goh Fernie , Long Robert , Simpson Nicholas , Sambanis Athanassios 
Published: April 2011

AbstractNoninvasive in vivo monitoring of tissue implants provides important correlations between construct function and the observed physiologic effects. As oxygen is a key parameter affecting cell and tissue function, we established a monitoring method that utilizes 19F nuclear magnetic resonance (NMR) spectroscopy, with perfluorocarbons (PFCs) as oxygen concentration markers, to noninvasively monitor dissolved oxygen concentration (DO) in tissue engineered implants. Specifically, we developed a dual PFC method capable of simultaneously measuring DO within a tissue construct and its surrounding environment, as the latter varies among animals and with physiologic conditions. In vitro studies using an NMR‐compatible bioreactor demonstrated the feasibility of this method to monitor the DO within alginate beads containing metabolically active murine insulinoma βTC‐tet cells, relative to the DO in the culture medium, under perfusion and static conditions. The DO profiles obtained under static conditions were supported by mathematical simulations of the system. In vivo, the dual PFC method was successful in tracking the oxygenation state of entrapped βTC‐tet cells and the surrounding peritoneal DO over 16 days in normal mice. DO measurements correlated well with the extent of cell growth and host cell attachment examined postexplantation. The peritoneal oxygen environment was found to be variable and hypoxic, and significantly lower in the presence of metabolically active cells. The significance of the dual PFC system in providing critical DO measurements for entrapped cells and other tissue constructs, in vitro and in vivo, is discussed. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
The effect of astrocytes on the induction of barrier properties in aortic endothelial cells
Authors: Shayan Gilda , Shuler Michael L. , Lee Kelvin H. 
Published: April 2011

AbstractConstruction of in vitro models of the blood‐brain barrier (BBB) using primary brain microvascular endothelial cells (BMEC) is time intensive and not high throughput, in part due to a lack of culture purity, low yields, and cellular dedifferentiation after the first passage. This problem has created interest in the substitution of BMEC with immortalized brain endothelial cells (EC), or peripheral EC such as bovine aortic EC (BAEC). Many BBB models have focused on further inducing the brain and peripheral ECs by incorporating astrocyte back‐to‐back or nonback‐to‐back cocultures. However, previous studies demonstrating induction effects of astrocytes on BAEC in back‐to‐back cocultures failed to recognize the extensive barrier properties of astrocytes alone, which can have a significant effect on interpreting the results. This manuscript reports the establishment of back‐to‐back and nonback‐to‐back cocultures between astrocytes and BAEC or BMEC (as a control) with primary focus on the properties of astrocytes alone and with a linear contrast statistical methodology to interpret the results. Transendothelial electrical resistance and permeability studies revealed that astrocytes can significantly increase the barrier tightening of BMEC by 167%, while having no effect on BAEC. Immunocytochemical studies also revealed the reorganization of BMEC occludin junctions in the presence of astrocytes, while indicating the absence of this junctional protein in BAEC. In contrast to a previous report, here the linear contrast statistical analysis revealed that observed decreases in permeability of BAEC in back‐to‐back cocultures is due to the addition of astrocytes' properties in series and not due to induction. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Crystallization and liquid‐liquid phase separation of monoclonal antibodies and fc‐fusion proteins: Screening results
Authors: Trilisky Egor , Gillespie Ronald , Osslund Timothy D. , Vunnum Suresh 
Published: April 2011

AbstractCrystallization holds the potential to be used for protein purification and low‐viscosity drug substance and drug product formulations. Twenty‐two different proteins (20 monoclonal antibodies and two Fc‐fusions) were examined to determine the breadth of applicability of crystallization to these therapeutic proteins. Vapor diffusion technique and an evaporative screening method were used to identify crystallization conditions using around a 100 initial conditions based on reagents that are generally regarded as safe (GRAS). Of 16 IgG2s examined, at least four formed diffraction‐quality crystals and four others formed crystal‐like particles. At least three of the IgG2s that crystallized well were also crystallized under the same set of operating conditions using inexpensive GRAS reagents. The crystals were formed to high‐yields in a few hours and were dissolved quickly without impacting product quality. Although only a fraction of the proteins examined crystallized, all exhibited liquid‐liquid phase separation (LLPS), which could be used for their concentration or possibly purification. One of the Fc‐fusions, for example, was concentrated by LLPS to a self‐buffering solution at 150 g/L. Crystallization and LLPS in the salting‐in region were shown to be feasible. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Gas‐permeable membranes and co‐culture with fibroblasts enable high‐density hepatocyte culture as multilayered liver tissues
Authors: Evenou Fanny , Hamon Morgan , Fujii Teruo , Takeuchi Shoji , Sakai Yasuyuki 
Published: April 2011

AbstractTo engineer reliable in vitro liver tissue equivalents expressing differentiated hepatic functions at a high level and over a long period of time, it appears necessary to have liver cells organized into a three‐dimensional (3D) multicellular structure closely resembling in vivo liver cytoarchitecture and promoting both homotypic and heterotypic cell–cell contacts. In addition, such high density 3D hepatocyte cultures should be adequately supplied with nutrients and particularly with oxygen since it is one of the most limiting nutrients in hepatocyte cultures. Here we propose a novel but simple hepatocyte culture system in a microplate‐based format, enabling high density hepatocyte culture as a stable 3D‐multilayer. Multilayered co‐cultures of hepatocytes and 3T3 fibroblasts were engineered on collagen‐conjugated thin polydimethylsiloxane (PDMS) membranes which were assembled on bottomless frames to enable oxygen diffusion through the membrane. To achieve high density multilayered co‐cultures, primary rat hepatocytes were seeded in large excess what was rendered possible due to the removal of oxygen shortage generally encountered in microplate‐based hepatocyte cultures. Hepatocyte/3T3 fibroblasts multilayered co‐cultures were maintained for at least 1 week; the so‐cultured cells were normoxic and sustained differentiated metabolic functions like albumin and urea synthesis at higher levels than hepatocytes monocultures. Such a microplate‐based cell culture system appears suitable for engineering in vitro miniature liver tissues for implantation, bioartificial liver (BAL) development, or chemical/drug screening. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011.