bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology control of various aromatic Polyimidazoles—preparation of nanofibers
Authors: Gong Jin , Uchida Tetsuya , Yamazaki Shinichi , Kimura Kunio 
Published: March 2011

AbstractMorphology of four kinds of aromatic polyimidazoles was examined by using reaction‐induced crystallization during solution polymerization at a concentration of 1% at 350°C in liquid paraffin (LPF), dibenzyltoluene (DBT), and the mixture of these solvents. Aggregates of ribbon‐like crystals of poly[2,6‐(2,6‐naphthalene)‐benzobisimidazole] were obtained in LPF, and those of plate‐like crystals were obtained in DBT/LPF‐50 and in DBT. In contrast to this, the network structures of poly[2,2′‐(2,6‐naphthalene)‐5,5′‐bibenzimidazole)] (PNT‐BBI) nanofibers with the diameter of 25 to 90 nm was mainly obtained in DBT. The network structures of the PNT‐BBI nanofibers could be recognized as nonwoven fabrics of the high‐performance polymers. Imidazole trimers were precipitated to form the ribbon‐like crystals and then they were continuously supplied from solution to grow the crystals. Molecular weight increased by the polymerization on the surface of the crystals when they crystallized and in the crystals. The initially formed aggregates of ribbon‐like crystals changed to the nanofibers with time. In the case of poly[2,6‐(4,4′‐biphenylene)‐benzobisimidazole] and poly[2,2′‐(4,4′‐biphenylene)‐5,5′‐bibenzimidazole)], they exhibited various morphologies such as spheres, lath‐like crystals, and the spherical aggregates of lath‐like crystals depending on the solvent, but fibers like PNT‐BBI were not formed. The crystals obtained in this study possessed very high crystallinity and the outstanding thermal stability measured by TGA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical properties and morphological changes of poly(lactic acid)/polycarbonate/poly(butylene adipate‐co‐terephthalate) blend through reactive processing
Authors: Kanzawa Takeshi , Tokumitsu Katsuhisa 
Published: March 2011

AbstractThe mechanical properties and morphological changes of poly(lactic acid) (PLA), polycarbonate (PC), and poly(butylene adipate‐co‐terephthalate) (PBAT) polymer blends were investigated. Several types of blend samples were prepared by reactive processing (RP) with a twin‐screw extruder using dicumyl peroxide (DCP) as a radical initiator. Dynamic mechanical analyses (DMA) of binary polymer blends of PC/PBAT indicated that each component was miscible over a wide range of PC/PBAT mixing ratios. DMA of PLA/PBAT/PC ternary blends revealed that PBAT is miscible with PC even in the case of ternary blend system and the miscibility of PLA and PBAT can also be modified through RP. As a result, the tensile strain and impact strength of the ternary blends was increased considerably through RP, especially for PLA/PBAT/PC = 42/18/40 (wt/wt/wt) with DCP (0.3 phr). Scanning electron microscopy (SEM) analysis of the PLA/PBAT/PC blends revealed many small spherical island phases with a domain size of approximately 0.05–1 μm for RP, whereas it was approximately 10 μm without RP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of Cyclic Selenenate/Seleninate Esters Stabilized byortho‐Nitro Coordination: Their Glutathione Peroxidase‐Like Activities
Authors: Singh Vijay P. , Singh Harkesh B. , Butcher Ray J. 
Published: March 2011

AbstractThe syntheses of selenenate/seleninate esters and related derivatives by aromatic nucleophilic substitution (SNAr) reactions of 2‐bromo‐3‐nitrobenzylalcohol (13) and 2‐bromo‐3‐nitrobenzaldehyde (17) with Na2Se2/nBuSeNa are described. The reaction of13with Na2Se2at room temperature afforded 7‐nitro‐1,2‐benzisoselenole(3 H) (15) instead of the desired diaryl diselenide14. Oxidation of selenenate ester15with hydrogen peroxide afforded the corresponding selenium(IV) derivative, 7‐nitro‐1,2‐benzisoselenole(3 H) selenium oxide (18). 2‐(Butylselanyl)‐3‐nitrobenzaldehyde (19) was synthesized by treating compound17with in situ generatednBuSeNa. The bromination reaction of selenide19did not afford the expected arylselenenyl bromide20, instead, it resulted in the formation of the unexpected 7‐nitro‐1,2‐benzisoselenol(3 H)‐3‐ol (21) and 3,3′‐oxybis(7‐nitro‐1,2‐benzisoselenole(3 H)) (22), respectively. The facile formation of heterocycles21and22is rationalized in terms of the aromatic ring strain in selenenyl bromide20. The presence of intramolecular secondary Se⋅⋅⋅O interactions in esters15,18,21,22, and selenenic anhydride29has been confirmed by single‐crystal X‐ray diffraction studies as well as computational studies. The presence of an intramolecular Se⋅⋅⋅O interaction in esters4b,8,15,18,21, and22has been further proved by natural bond orbital (NBO) and atoms in molecules (AIM) calculations. Glutathione peroxidase‐like (GPx) antioxidant activities of15,18,21,22, and related heterocycles such as 7‐nitro‐1,2‐benzisoselenol(2 H)‐3‐one selenium oxide (4b), 7‐nitro‐1,2‐benzisoselenol(2 H)‐3‐one (8), and29have been determined by the coupled reductase assay.
DNA Interstrand Cross‐Links of an Antitumor Trinuclear Platinum(II) Complex: Thermodynamic Analysis and Chemical Probing
Authors: Malina Jaroslav , Farrell Nicholas P. , Brabec Viktor 
Published: March 2011

AbstractThe trinuclear platinum compound [{trans‐PtCl(NH3)2}2(μ‐trans‐Pt(NH3)2{NH2(CH2)6NH2}2)]4+ (BBR3464) belongs to the polynuclear class of platinum‐based anticancer agents. These agents form in DNA long‐range (Pt,Pt) interstrand cross‐links, whose role in the antitumor effects of BBR3464 predominates. Our results show for the first time that the interstrand cross‐links formed by BBR3464 between two guanine bases in opposite strands separated by two base pairs (1,4‐interstrand cross‐links) exist as two distinct conformers, which are not interconvertible, not only if these cross‐links are formed in the 5′‐5′, but also in the less‐usual 3′‐3’ direction. Analysis of the conformers by differential scanning calorimetry, chemical probes of DNA conformation, and minor groove binder Hoechst 33258 demonstrate that each of the four conformers affects DNA in a distinctly different way and adopts a different conformation. The results also support the thesis that the molecule of antitumor BBR3464 when forming DNA interstrand cross‐links may adopt different global structures, including different configurations of the linker chain of BBR3464 in the minor groove of DNA. Our findings suggest that the multiple DNA interstrand cross‐links available to BBR3464 may all contribute substantially to its cytotoxicity.
Induction of drug efflux protein expression by venlafaxine but not desvenlafaxine
Authors: Bachmeier Corbin J. , Beaulieu‐Abdelahad David , Ganey Nowell J. , Mullan Michael J. , Levin Gary M. 
Published: March 2011

AbstractVenlafaxine and its metabolite desvenlafaxine are serotonin‐norepinephrine reuptake inhibitors currently prescribed for the treatment of depression. Previously, it was reported that venlafaxine is an inducer of MDR1, the gene responsible for P‐glycoprotein (P‐gp). The present study expanded upon these findings by examining the effect of venlafaxine and desvenlafaxine on the expression of both P‐gp and the breast cancer resistance protein (BCRP) in human brain endothelial cells (HBMEC), an in vitro model of the blood–brain barrier (BBB). The HBMEC were treated for 1 h with various concentrations (500 nM to 50 µM) of venlafaxine and desvenlafaxine. Western blot analysis revealed treatment with venlafaxine significantly induced the expression of P‐gp (2‐fold) and BCRP (1.75‐fold) in a dose‐dependent manner, while treatment with desvenlafaxine had no effect on drug efflux transporter expression. To determine the functional significance of this effect, the permeability of a known drug efflux probe, rhodamine 123, across the BBB model and Caco‐2 cells, a model of intestinal absorption, were examined. Treatment with venlafaxine (1–50 µM) for 1 h significantly reduced the apical‐to‐basolateral permeability of R123 across the BBB model (30%) and Caco‐2 cell monolayers (25%), indicative of increased drug efflux transporter expression at the apical membrane. Conversely, desvenlafaxine had no effect on R123 permeability in either cellular model. These studies indicate that venlafaxine, but not desvenlafaxine is an inducer of drug efflux transporter expression, which consequently increases the potential for clinical drug–drug interactions. Therefore, based on these preliminary results, caution should be taken when prescribing venlafaxine with other P‐gp substrates. Copyright © 2011 John Wiley & Sons, Ltd.
In vitro effects of low frequency electromagnetic fields on osteoblast proliferation and maturation in an inflammatory environment
Authors: Lin Hsin‐Yi , Lin Yu‐Jen 
Published: March 2011

AbstractAn in vitro model was set up to investigate the effects of low frequency pulsed electromagnetic fields (PEMF) and its induced electric fields on osteoblast cells under inflammatory conditions. Osteoblasts (7F2) were seeded on top of chitosan scaffolds and co‐cultured with macrophage cells (RAW 264.7) growing on the bottom of culture wells, stimulated by lipopolysaccharide to release reactive oxygen species including nitric oxide (NO). The co‐culture was exposed to PEMF (magnitude of the magnetic field = 1.5 mT; induced electric voltage = 2.5 mV; frequency = 75 Hz; pulse duration = 1.3 ms) for 9 h. The osteoblasts were examined for their proliferation, viability, alkaline phosphatase (ALP) activity, and genetic expressions of type I collagen (COL I) and osteocalcin (OC), immediately and 7 days after PEMF exposure (days 0 and 7). Macrophage cell viability and NO concentration in the medium were monitored before and after PEMF exposure. The PEMF‐exposed co‐culture released a significantly higher amount of NO (65 µM) compared to control (17 µM) on day 7. Despite the high level of NO in the medium that was reported to be cytotoxic, PEMF‐exposed osteoblasts had enhanced cell proliferation (23%), viability (36%), and COL I mRNA expression (3.4‐fold) compared to the controls. The osteoblasts subjected to the PEMF had 41% less ALP activity than the control, which was associated with the active cell proliferation and COL I expression. The expression of OC mRNA was not seen in either the PEMF or control group, indicating cells had not entered the mineralization stage by day 7. Bioelectromagnetics 32:552–560, 2011. © 2011 Wiley‐Liss, Inc.
Randomized phase II clinical trial of avotermin versus placebo for scar improvement
Authors: McCollum P T , Bush J A , James G , Mason T , O'Kane S , McCollum C , Krievins D , Shiralkar S , Ferguson M W J 
Published: March 2011

Abstract

Background
Scarring is a major problem following skin injury. In early clinical trials, transforming growth factor β3 (avotermin) improved scar appearance. The aim of this study was to determine whether an injection of avotermin at the time of wound closure is effective in improving scar appearance.

Methods
Study RN1001-0042, a double-blind, randomized, within-patient, placebo-controlled trial, investigated the efficacy and safety of four doses of avotermin given once. Patients undergoing bilateral surgery to remove varicose leg veins by saphenofemoral ligation and long saphenous vein stripping were enrolled at 20 European centres. A total of 156 patients were randomized to receive one of four doses of avotermin (5, 50, 200 or 500 ng per 100 µl, at 100 µl per linear cm of wound margin), administered by intradermal injection to the groin and distal wound margins of one leg; placebo was administered to the other leg. Scar appearance was evaluated by an independent panel of lay people (lay panel), investigators and patients. The primary efficacy variable was lay panel Total Scar Score (ToScar), derived from visual analogue scale scores for groin scars between 6 weeks and 7 months.

Results
Avotermin 500 ng significantly improved groin scar appearance compared with placebo (mean lay panel ToScar difference 16·49 mm; P = 0·036).

Conclusion
Avotermin 500 ng per 100 µl per linear cm of wound margin given once is well tolerated and significantly improves scar appearance. Registration number: NCT00430326 (http://www.clinicaltrials.gov).
High intra-abdominal pressure during experimental laparoscopic liver resection reduces bleeding but increases the risk of gas embolism
Authors: Eiriksson K , Fors D , Rubertsson S , Arvidsson D 
Published: March 2011

Abstract

Background
Various recommendations exist regarding intra-abdominal pressure (IAP) during laparoscopic liver resection. A high IAP may reduce bleeding but at the same time increase the risk of gas embolism. This study investigated the effects of two different IAPs during laparoscopic left liver lobe resection in piglets.

Methods
Sixteen piglets underwent laparoscopic left liver lobe resection using carbon dioxide pneumoperitoneum of either 8 or 16 mmHg (8 per group). A combination of CUSA System 200™ and LigaSure™ instruments was used for parenchymal division. During resection, a standard injury to the left liver vein was also created to increase the risk of bleeding and/or gas embolism during the operation. Heart rate, cardiac output, and arterial, pulmonary arterial, pulmonary capillary wedge and central venous pressures were measured. Arterial blood gases were monitored continuously. Transoesophageal echocardiography was video recorded to detect and quantify gas embolism within the right cardiac ventricle. The duration of operation and bleeding were noted.

Results
High IAP resulted in reduced bleeding (P = 0·016), but gas embolism occurred more frequently (P = 0·001) than with low IAP. Gas embolism disturbed gas exchange, with an increase in arterial pressure of carbon dioxide, and a decrease in arterial partial pressure of oxygen and pH. These effects were sustained for at least 30 min after surgery.

Conclusion
High IAP reduces the amount of bleeding but increases the risk of gas embolism. Monitoring for gas embolism is therefore indicated if a high IAP is used during laparoscopic liver resection.
Protein Interactions in the Escherichia coli Cytosol: An Impediment to In‐Cell NMR Spectroscopy
Authors: Crowley Peter B. , Chow Elysian , Papkovskaia Tatiana 
Published: March 2011

AbstractProtein science is shifting towards experiments performed under native or native‐like conditions. In‐cell NMR spectroscopy for instance has the potential to reveal protein structure and dynamics inside cells. However, not all proteins can be studied by this technique. 15N‐labelled cytochrome c (cyt c) over‐expressed in Escherichia coli was undetectable by in‐cell NMR spectroscopy. When whole‐cell lysates were subjected to size‐exclusion chromatography (SEC) cyt c was found to elute with an apparent molecular weight of >150 kDa. The presence of high molecular weight species is indicative of complex formation between cyt c and E. coli cytosolic proteins. These interactions were disrupted by charge‐inverted mutants in cyt c and by elevated concentrations of NaCl. The physiologically relevant salt, KGlu, was less efficient at disrupting complex formation. Notably, a triple mutant of cyt c could be detected in cell lysates by NMR spectroscopy. The protein, GB1, yields high quality in‐cell spectra and SEC analysis of lysates containing GB1 revealed a lack of interaction between GB1 and E. coli proteins. Together these data suggest that protein “stickiness” is a limiting factor in the application of in‐cell NMR spectroscopy.
Mesoporous Glass Membranes as Model Systems to Study Gas Diffusion through Porous Media
Authors: Stoltenberg D. , Seidel‐Morgenstern A. , Enke D. 
Published: March 2011

AbstractPorous glass monoliths are suitable model systems to study pore size‐related effects in gas diffusion. Here, mesoporous glass membranes with different surface properties and pore diameters covering the lower mesopore range were synthesized and used to study gas permeation of adsorbable and non‐adsorbable gases. Dynamic single gas permeation measurements were performed using a modified Wicke‐Kallenbach cell. Chemical surface modification of the inner surface of the membranes resulted in altered adsorption and diffusion properties.
Monitoring of biogas test plants—a process analytical technology approach
Authors: Holm‐Nielsen Jens Bo , Esbensen Kim H. 
Published: March 2011

AbstractMost studies reported in the literature have investigated near infrared spectroscopy (NIR) in laboratory‐scale or minor pilot biogas plants only; practically no other studies have examined the potential for meso‐scale/full‐scale on‐line process monitoring. The focus of this study is on a meso‐scale biogas test plant implementation of process analytical technologies (PAT) to develop multivariate calibration/prediction models for anaerobic digestion (AD) processes. A 150 L bioreactor was fitted with a recurrent loop at which NIR spectroscopy and attendant reference sampling were carried out. In all realistic bioreactor scales, it is necessary to obtain a fairly constant level of volatile fatty acid (VFA) concentration, which furthers a stable biogas production. Uncontrolled VFA contents have a significant negative impact on biogas production; VFA concentrations should not exceed 5–6000 mg/L lest the microorganism population may suffer fatal reductions. On‐line control and management of VFA concentration levels are therefore critical in order to be able to speed up or slow down the AD processes which produce the desired sustainable bioenergy for combined heat and power production. By calibrating pilot plant NIR spectra to laboratory VFA reference concentrations at the experimental locality Bygholm, it was possible to develop calibration models by partial least squares (PLS) regression, which displayed acceptable to very good prediction performances for total VFA as well as for three other essential individual acids based on test set validations. The average statistics assessing prediction performance, accuracy (slope) and precision (explained variance r2), were both 0.92, which must be considered excellent for this type of significantly heterogeneous systems. The meso‐ to full‐scale feasibility has thus been proven, which has important positive implications for robust, sufficient and reliable, low‐cost PAT monitoring systems in the biogas arena and other continuous fermentation processes. Copyright © 2011 John Wiley & Sons, Ltd.
Simulating spin dynamics in NMR with a new computer program intended for education: Insensitive
Authors: Boldt Klaus 
Published: March 2011

AbstractThe NMR experiment is usually described by a choice of three models that operate on different levels of abstraction: the vector model, the product operator formalism and the density matrix approach. The transition between these models poses a didactic challenge for teacher and student alike. A new computer program is presented, which simulates a spin system on the textbook level and compares the three approaches, with the possibility to manipulate the system at every step. It closes a gap between NMR education and professional simulation tools. Some algorithms are explained, which are used in the simulation to extract information from the density matrix. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38A: 17–24, 2011.
The COSY and DQF‐COSY NMR spectra for systems of three spins I = 7/2
Authors: Kempgens P. 
Published: March 2011

AbstractThe two‐dimensional nuclear magnetic resonance (NMR) correlation spectroscopy (COSY) and double quantum‐filtered COSY (DQF‐COSY) spectra of an AMX and an AX2 systems of spins I = 7/2 have been calculated by numerical density matrix calculations. The results are presented in three extreme cases, namely in the slow relaxation regime, the intermediate relaxation regime, and in the fast relaxation regime. It is concluded for such spin systems, as was recently shown in the case of an AX system of spins I = 3/2, that in addition to the usual advantages that the DQF‐COSY NMR experiment offer compared to the conventional COSY NMR experiment (observation of only‐coupled spins, antiphase character of both diagonal and cross‐peaks, and intensity of the cross‐peaks comparable to the intensity of the diagonal peaks), the DQF‐COSY NMR experiment appear to be more powerful for observation, interpretation, and analysis than the conventional COSY NMR experiment, and this is particularly true for quadrupolar nuclei relaxing usually very quickly and/or small coupling constants. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38A: 74–83, 2011.
Proton‐based radiotherapy for unresectable or incompletely resected osteosarcoma
Authors: Ciernik I. Frank , Niemierko Andrzej , Harmon David C. , Kobayashi Wendy , Chen Yen‐Lin , Yock Torunn I. , Ebb David H. , Choy Edwin , Raskin Kevin A. , Liebsch Norbert , Hornicek Francis J. , DeLaney Thomas F. 
Published: March 2011

AbstractBACKGROUND:A study was undertaken to assess clinical outcome and the role of proton therapy for local control of osteosarcoma (OSA).METHODS:All patients who received proton therapy or mixed photon‐proton radiotherapy from 1983 to 2009 at the Massachusetts General Hospital were reviewed. Criteria for proton therapy were the need for high dose in the context of highly conformal radiotherapy of unresected or partially resected OSA, positive postoperative margins, postoperative imaging studies with macroscopic disease, or incomplete resection as defined by the surgeon. The primary endpoint was local control of the site treated; secondary endpoints were disease‐free survival (DFS), overall survival (OS), long‐term toxicity, and prognostic factors associated with clinical outcome.RESULTS:Fifty‐five patients with a median age of 29 years (range, 2‐76 years) were offered proton therapy. The mean dose was 68.4 gray (Gy; standard deviation, 5.4 Gy). Of the total dose, 58.2% (range, 11%‐100%) was delivered with protons. Local control after 3 and 5 years was 82% and 72%, respectively. The distant failure rate was 26% after 3 and 5 years. The 5‐year DFS was 65%, and the 5‐year OS was 67%. The extent of surgical resection did not correlate with outcome. Risk factors for local failure were ≥2 grade disease (P < .0001) and total treatment length (P = .008). Grade 3 to 4 late toxicity was seen in 30.1 % of patients. One patient died from treatment‐associated acute lymphocytic leukemia, and 1 from secondary carcinoma of the maxilla.CONCLUSIONS:Proton therapy to deliver high radiotherapy doses allows locally curative treatment for some patients with unresectable or incompletely resected OSA. Cancer 2011;. © 2011 American Cancer Society.