bluuebunny/crossref_metadata_2025 huggingface dataset:
Pancreatic adenocarcinoma in a young patient population—12‐year experience at Memorial Sloan Kettering Cancer Center
Authors: Duffy A. , Capanu M. , Allen P. , Kurtz R. , Olson S.H. , Ludwig E. , Klimstra D.S. , O'Reilly E.M.
Published: April 2009

Background

There is a dearth of data in a younger population of patients with pancreatic ductal adenocarcinoma (PAC) regarding epidemiology, genetics, prognosis, and outcome. This report examines a large cohort of patients with PAC ≤45 years of age evaluated at MSKCC over a 12‐year period.

Methods

A retrospective analysis of patients referred to MSKCC with PAC identified from the institutional tumor registry, who were ≤45 years on the date of the diagnostic biopsy, between January 1995 and February 2008, was performed. Information reviewed included demographics, clinical and pathological staging, surgical management, therapy, date of relapse, death or last follow‐up. Survival curves were estimated using the Kaplan–Meier method and compared using the log‐rank test.

Results

One hundred thirty‐six cases of PAC, age ≤45 years at diagnosis, were identified. Seventy‐four (54%) females, 62 (46%) males. Age range: 24–45; 4, 38, and 94 patients in age groups 20–29, 30–39, 40–45 years, respectively. Fifty (37%) had a smoking history. Fourteen (10.3%) had a positive family history of PAC. Thirty‐five (25.7%) underwent a curative resection for localized disease. Twenty‐eight (20.1%) presented with locally advanced, inoperable disease. Sixty‐eight (50%) presented as AJCC Stage IV. Twenty‐three (37%) of those resected underwent adjuvant chemoradiation. Thirteen received adjuvant gemcitabine. The median overall survival for the entire cohort was 12.3 months (95% CI 10.2–14.0 months). The median overall survival for the patients with locally resectable disease was 41.8 months (95% CI 20.3–47 months). The median overall survival for the patients who presented with locally advanced, unresectable disease was 15.3 months (95% CI 12–19.3 months). The median overall survival for those who presented with metastatic disease was 7.2 months (95% CI 5.2–9.5 months).

Conclusions

This is the largest reported cohort of young patients with PAC ≤45 years of age. The data suggest that patients with stages I–II disease may have an improved prognosis, however the prognosis for stages III–IV patients appears to be similar to the typical (older) patient population with PAC. J. Surg. Oncol. 2009;100:8–12. © 2009 Wiley‐Liss, Inc.
Properties and Bioapplications of Blended Cellulose and Corn Protein Films
Authors: Yang Quanling , Lue Ang , Qi Haisong , Sun Yunxia , Zhang Xianzheng , Zhang Lina
Published: April 2009

A series of blend films have been prepared from cellulose and corn protein in a NaOH/urea solution by a simple, low cost, and ‘green’ pathway. Their structure and properties are characterized by amino acid analysis, X‐ray diffraction, scanning electron microscopy, thermogravimetry, and tensile testing. The results reveal that a certain miscibility exists between cellulose and corn protein and their thermal stability and mechanical properties are improved significantly, compared with the protein materials, when the protein content is less than 18 wt.‐%. The protein, which contains tyrosine and histidine, could remain in the blend films after being washed for ten days, which indicates the strong hydrogen bonding between the hydroxy groups of cellulose and the hydroxyphenyl of tyrosine and imidazolyl of histidine in the protein. Furthermore, they exhibit good biocompatibility capable of supporting cell adhesion and proliferation.

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Gel‐Like Structure of a Hexadecyl Derivative of Hyaluronic Acid for the Treatment of Osteoarthritis
Authors: Finelli Ivana , Chiessi Ester , Galesso Devis , Renier Davide , Paradossi Gaio
Published: April 2009

Hyaluronic acid is a polysaccharide with viscoelastic and mechanical properties that are crucial for the normal functioning of osteoarticular junctions. It is demonstrated that introduction of a hexadecyl side chain into HA yields an injectable polysaccharide capable of forming physical hydrogels, which are stable at very low polymer concentrations, whereas native hyaluronic acid forms viscous solutions at concentrations that are ten times higher. Characterization of this system showed that the driving force for its gel‐like behavior is the occurrence of hydrophobic interactions involving aliphatic side chains, despite the low degree of substitution, as confirmed by molecular dynamics simulations of HYADD4 and HA hydrogels.

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Reverse Thermal Organogelation of Poly(ethylene glycol)‐Polypeptide Diblock Copolymers in Chloroform
Authors: Choi Yun Young , Jeong Yuri , Joo Min Kyung , Jeong Byeongmoon
Published: April 2009

Most organogel formation has been observed at low temperatures and the gel melts as the temperature increases. As an opposite case to traditional organogels, we report a reverse thermal gelation of methoxy‐aminopoly(ethylene glycol)‐homopolypeptide block‐copolymer chloroform solutions that undergo a sol‐to‐gel transition as the temperature increases. A series of methoxy‐aminopoly(ethylene glycol)‐homopolypeptide block copolymers showing reverse thermal gelation in chloroform was synthesized and we prove that the secondary structure of the polypeptide determines the morphology of the organogel.

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Synthesis of Block Copolymers with a Pentasilane Core
Authors: Morisaki Yasuhiro , Otaka Hiromichi , Naka Kensuke , Chujo Yoshiki
Published: April 2009

We report a new method for the synthesis of block copolymers with a pentasilane core by the polymerization of alkyl methacrylate monomers using the pentasilyl dianion as an initiator. The polymerization proceeded with living features and yielded the corresponding block copolymers with controlled molecular weights. The amphiphilic block copolymer was obtained by the polymer reaction, and it formed sphere‐like aggregates in MeOH/H2O solution.

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Supramolecular Structures Generated by Spherical Polyelectrolyte Brushes and their Application in Catalysis
Authors: Lu Yan , Wittemann Alexander , Ballauff Matthias
Published: April 2009

We survey recent studies on composite particles made from spherical polyelectrolyte brushes (SPB) and catalytically active nanoparticles or enzymes. SPB consist of a solid core (diameter: ca. 100 nm) onto which long chains of anionic or cationic polyelectrolyte (PE) are densely grafted (“PE brush”). Immersed in water the PE layer affixed to the colloidal core will swell due to the enormous osmotic pressure of the confined counterions (“osmotic brush”). This confinement of the counterions can be used to generate metal nanoparticles on the surface of the SPB. Moreover, enzymes can be immobilized within the PE layer. In both cases, the resulting composite particles are stable against coagulation and can be easily handled and filtered off. The catalytic activity of both systems is largely preserved in case of the enzymes, in case of the metal nanoparticles it is even enhanced. Thus, the SPB present an excellent carrier system for applications in catalysis.

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Recent Advances in Solid‐State MAS NMR Methodology for Probing Structure and Dynamics in Polymeric and Supramolecular Systems
Authors: Brown Steven P.
Published: April 2009

This article reviews recent applications of novel 1H, 2H, 13C, 15N and 17O solid‐state MAS NMR methods that provide new insight into the structural and dynamic processes that determine the bulk properties of polymeric and supramolecular materials. The review highlights methods that exploit the sensitivity to structure and dynamics of the NMR chemical shift and quadrupolar coupling as well as the through‐space dipolar coupling and through‐bond J coupling. In particular, it is shown that solid‐state NMR exhibits marked sensitivity to key intra‐ and intermolecular hydrogen‐bonding and π–π interactions, allowing, for example, the very accurate determination of internuclear distances as well as the probing of dynamics over a very wide range of timescales.

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Synthesis and Aggregation Behavior of Multi‐Responsive Double Hydrophilic ABC Miktoarm Star Terpolymer
Authors: Zhang Yanfeng , Liu Hao , Hu Jinming , Li Changhua , Liu Shiyong
Published: April 2009

We report the first example of the synthesis and the “schizophrenic” micellization behavior of a multi‐responsive double hydrophilic ABC miktoarm star terpolymer. A well‐defined miktoarm star terpolymer consisting of poly(ethylene glycol), poly(2‐(diethylamino)ethyl methacrylate), and poly(N‐isopropylacrylamide) arms, PEG(‐b‐PDEA)‐b‐PNIPAM, was synthesized via the combination of atom transfer radical polymerization (ATRP) and click reaction. Containing pH‐responsive PDEA and thermo‐responsive PNIPAM arms, this novel type of miktoarm star terpolymer molecularly dissolves in aqueous solution at acidic pH and room temperature, but supramolecularly self‐assembles into PDEA‐core micelles at alkaline pH and room temperature, and PNIPAM‐core micelles at acidic pH and elevated temperatures. Most importantly, both types of micellar aggregates possess well‐solvated hybrid coronas.

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Precision Sulfonic Acid Ester Copolymers
Authors: Opper Kathleen L. , Wagener Kenneth B.
Published: April 2009

Linear ethylene copolymers containing sulfonic acid ethyl esters precisely spaced on every 21st carbon have been synthesized using metathesis polycondensation chemistry. These precision structures with one directly attached and one aromatic spaced sulfonic acid ester are synthesized with the goal of tailoring layered higher order morphologies in contrast to conventional clustered ionic polyolefins. Primary structural characterization confirms the precision polymer structures. Additional secondary microstructural analysis by DSC shows a recoverable endothermic melt transition of polyethylene‐like lamellae crystallites of the directly attached ester while completely amorphous behavior is observed when the ester is spaced away from the backbone with an aromatic group.

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Unusual Photopolymerization Behavior of Amino Acid‐Derived Polydiacetylene Supramolecules
Authors: Yoon Jaewon , Azizan Kamalrul Azlan Bin , Yoo Hyun Oh , Okada Shuji , Kim Jong‐Man
Published: April 2009

UV‐irradiation of aqueous suspensions of amino acid‐derived amphiphilic diacetylene supramolecules promotes a process that involves initial formation of species that absorb at 640 nm followed by the generation of polymers that have longer wavelength (686 nm) absorbance. The initially formed intermediate polydiacetylenes display substantial colorimetric reversibility while the long wavelength absorbing polymers show irreversible thermochromism during heating and cooling cycles. The long wavelength absorbing polydiacetylenes, formed from amino acid‐derived amphiphilic diacetylene supramolecules, are suggested to have more planer backbone structures that allow more efficient overlap of the conjugated p‐orbitals.

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Regioregulated Syntheses of Poly(aminopyridine)s by Pd‐catalyzed Amination Reaction
Authors: Kuwabara Junpei , Mori Hironori , Teratani Takuya , Akita Munetaka , Kanbara Takaki
Published: April 2009

Regioregulated poly(aminopyridine)s were synthesized by a Pd‐catalyzed CN coupling reaction. The polymerization using Pd(0) and a bulky monodentate phosphine ligand distinctively produced the para‐linked and meta‐linked poly(aminopyridine)s, without the need for a protection process. The regioregularity of the polymer was confirmed by 1H NMR spectroscopy. Model reactions were studied to evaluate the possibility of crosslinkage in the polymer. A large difference in reactivity was observed between 5‐amino‐2‐bromopyridine and 2‐amino‐5‐bromopyridine, which should have afforded same product. Density functional theory (DFT) calculations indicated that electron densities of the Br‐bound carbon atom and the pyridine‐nitrogen atom determine the reactivity of the monomers.

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Well‐Organized CdS/C60 in Block Copolymer Micellar Cores
Authors: Koh Haeng‐Deog , Lee Jung‐Pil , Lee Jae‐Suk
Published: April 2009

CdS nanoparticles of 4.5 nm diameter were synthesized in poly(2‐vinylpyridine) micellar cores which were obtained by solvating a polystyrene‐block‐poly(2‐vinylpyridine) block copolymer in polystyrene‐selective toluene. Then, a C60‐toluene solution was dispersed into the CdS micelle solution with stirring. This led to the well‐defined organization of two different nanoparticles; specifically: a CdS NP decorated by several/dozens of C60 molecules, because C60 molecules were strongly coordinated with pyridine molecules in the micellar cores by charge‐transfer complexation C–P2VPδ+. A harmoniously organized CdS/C60 micellar structure was clearly verified by transmission electron microscopy. Fluorescent quenching of CdS nanoparticles, which was strongly affected by neighboring C60 molecules, was observed.

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Synthesis, Characterization and Self‐Assembly of Novel Amphiphilic Block Copolymers with a Polyhedral Oligomeric Silsesquioxanes Moiety Attached at the Junction of the Two Blocks
Authors: Zhang Liang , Lu Dairen , Tao Kang , Bai Ruke
Published: April 2009

A novel well‐defined amphiphilic block copolymer, with the polyhedral oligomeric silsesquioxane (POSS) moiety at the junction of the two blocks of polystyrene and poly(ethylene oxide) (PEO), was designed and synthesized. First, a macroinitiator containing a POSS moiety and a PEO chain was prepared and then atom transfer radical polymerization of styrene was carried out in the presence of the macroinitiator in bulk. The polymerization results show that the process bears the characteristics of controlled/living free radical polymerizations. The structure and molecular weight of the polymers were characterized by GPC, 1H NMR, and FT‐IR spectroscopy. The self‐assembly behaviors of the polymers was investigated by TEM and SEM. It was observed that the polymers can self‐assemble into vesicles in aqueous solution.

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Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process
Authors: Sun Qunhui , Bi Wu , Fuller Thomas F. , Ding Yong , Deng Yulin
Published: April 2009

In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4‐aminothiophenol (4‐ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm−2, was synthesized.

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Free vascularized fibular grafting for treatment of osteonecrosis of the femoral head secondary to hip dislocation
Authors: Garrigues Grant E. , Aldridge J. Mack , Friend Jennifer K. , Urbaniak James R.
Published: April 2009

Traumatic dislocation of the hip results in osteonecrosis of the femoral head (ONFH) or avascular necrosis (AVN) in ∼40% of patients. This high‐energy event causes an ischemic insult to the femoral head that may lead to ONFH. Here, we investigate use of Free‐Vascularized Fibular Grafting (FVFG) in patients with ONFH after traumatic hip dislocation. Thirty‐five patients with FVFG for this indication were reviewed (average follow‐up 3.3 years, range 1–21). We reviewed patient injury statistics, demographics, preoperative radiographs, pre‐ and postoperative Harris Hip scores, complications, and rate of conversion to total hip arthroplasty (THA). The majority (81%) of our patients were young males (22 years) with ONFH diagnosed an average of 2 years after injury. The average preoperative Harris Hip score was 64.9 which improved by over 10 points to 76.1 at 1‐year follow‐up. Seven of 35 patients required conversion to THA at an average of 45 (13–86) months postoperation. After a maximum follow up of 21 years, the remainder of the patients retained their native hips and Harris Hip scores tended to show improved hip function. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Treatment of avulsion injury of three fingers with a compound thoracodorsal artery perforator flap including serratus anterior fascia
Authors: Ulrich Dietmar , Pallua Norbert
Published: April 2009

Complete degloving injury of three digits not amenable to revascularization may leave poor cosmetic and functional results. We used a compound thoracodorsal artery perforator (TDAP) flap in a 34‐year‐old, right‐handed, male worker with traumatic degloving injury. The flap consisted of a thin nonbulky skin component isolated on two perforators in combination with serratus fascia, both pedicled on the thoracodorsal vessels. The mobility of the two flap components allowed the palmar and dorsal part of the fingers to be reconstructed without relying on multiple flaps or anastomoses. The skin component of the TDAP flap was transferred to the palmar defect, the serratus fascia flap to the dorsal part of the fingers and sutured loosely. Coverage of the serratus anterior fascia was done with split‐thickness skin graft. Both components of the flap survived completely. One month after the first operation, the surgical syndactyly between middle and ring finger was separated, one month later the syndactyly between the ring and little finger. Good coverage of the soft tissue defects with good function could be achieved. There were no donor‐site problems. Therefore, we consider the compound TDAP flap as a useful method that provides functional and cosmeticcoverage of severe avulsion injury of multiple digits. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
Lip replantation and delayed inset after a dog bite: A case report and literature review
Authors: Taylor Helena O. B. , Andrews Brian
Published: April 2009

Dog bites to the face are common in children and often involve amputation of the lip or cheek resulting in a devastating facial injury. When feasible, replantation of the amputated lip segment provides the optimal cosmetic outcome. Here, we present the case of a partial upper lip replantation with delayed inset as a new treatment option. Revascularization of the central upper lip segment was enabled by anastomosis to a single labial artery. Inset compression at the time of initial closure caused arterial insufficiency. Therefore, a delayed, sequential inset was performed over the following 2 weeks resulting in an esthetically and functionally successful replantation. A comprehensive review of the literature on published lip replantation techniques is also provided and discussed. We add delayed inset to the armamentarium of the microsurgeon when faced with these difficult injuries. © 2009 Wiley‐Liss, Inc. Microsurgery, 2009.
A second‐order optimization algorithm using quadric control updates for multistage optimal control problems
Authors: Patel Prashant , Scheeres Daniel J.
Published: April 2009

This paper describes a trajectory optimization algorithm that generates a quadric control update, which satisfies the constraints and necessary conditions to the second order. The algorithm is designed to solve multistage optimization problems. The algorithm is tested against a commercially available Sequential Quadratic Programming algorithm on problems with linear dynamics and linear and nonlinear constraints. This algorithm is a departure from previous methods because it explicitly satisfies the constraints to the second order. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamic advertising with spillovers: Cartel vs competitive fringe
Authors: Lambertini Luca , Palestini Arsen
Published: April 2009

A differential oligopoly game with advertising is investigated, where different dynamics occur between two groups of agents, the former playing a competitive Nash game and the latter cooperating as a cartel. Sufficient conditions for stability and a qualitative analysis of the profit ratio and social welfare at equilibrium are provided. A threshold value for the size of the competitive fringe is pointed out by a suitable numerical simulation. Copyright © 2009 John Wiley & Sons, Ltd.
Reduced expression and novel splice variants of ING4 in human gastric adenocarcinoma
Authors: Li Ming , Jin Yan , Sun Wen‐jing , Yu Yang , Bai Jing , Tong Dan‐dan , Qi Ji‐ping , Du Jin‐rong , Geng Jing‐shu , Huang Qi , Huang Xiao‐yi , Huang Yun , Han Fei‐fei , Meng Xiang‐ning , Rosales Jesusa L , Lee Ki‐Young , Fu Song‐bin
Published: April 2009

ING4, a new member of the ING (inhibitor of growth) family of tumour suppressor genes, has been found to be deleted or down‐regulated in gliomas, breast tumours, and head and neck squamous cell carcinomas. The goal of the present study was to investigate whether the expression and alternative splicing of ING4 transcripts are involved in the initiation and progression of stomach adenocarcinoma. ING4 mRNA and protein expression was examined in gastric adenocarcinoma tissues and human gastric adenocarcinoma cell lines by RT‐PCR, real‐time RT‐PCR, tissue microarray immunohistochemistry, and western blot analysis. Alterations in ING4 transcripts were determined through sequence analysis of ING4 cDNA. Our data showed that ING4 mRNA and protein were dramatically reduced in stomach adenocarcinoma cell lines and tissues, and significantly less in female than in male patients. We also found that reduced ING4 mRNA expression correlated with the stage of the tumour. Interestingly, by sequence analysis, we discovered five novel aberrantly spliced variant forms of ING4_v1 and ING4_v2. These variants cause a codon frame‐shift and, eventually, deletion of the NLS or PHD domain contributing to the mislocalization of p53 and/or HAT/HDAC complexes and, subsequently, altered gene expression in gastric adenocarcinoma. These results suggest that attenuated and aberrant ING4 expression may be involved in the initiation and progression of stomach adenocarcinoma. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Novel poly(phenylene ethynylene)‐type conjugated polymers containing diketopyrrolopyrrole or triphenylpyrazoline units in the main chain: synthesis, characterization and photophysical properties
Authors: Zhang Guoqiang , Liu Kuan , Li Yang , Yang Mujie
Published: April 2009

BACKGROUND: Polymer‐based light emitting diodes (PLEDs) have received considerable attention as they combine the good mechanical and processing properties of polymers with semiconducting behavior, and can be easily fabricated as flexible devices. To obtain high‐performance PLED materials by balancing the carrier injection of poly(phenylene ethynylene)s (PPEs), polymers containing two aryl‐heterocyclic rings, namely diketopyrrolopyrrole (DPP) or triphenylpyrazoline (TPP), have been synthesized and investigated.

RESULTS: PPE‐type polymers containing DPP or TPP units were synthesized using Heck–Sonogashira coupling methodology and characterized by 1H NMR, Fourier transform infrared and UV‐visible spectroscopies, elemental analysis, gel permeation chromatography, photoluminescence (PL), X‐ray diffraction, thermogravimetic analysis and cyclic voltammetry. The polymers obtained are easily soluble in common solvents and form smooth and uniform films. They are yellow or red emitters as revealed by PL. In addition, they show large Stokes shifts, which is in agreement with their twisted molecular structures determined via quantum chemical calculations.

CONCLUSION: PPE‐type polymers containing DPP or TPP units were successfully synthesized by coupling polymerization. They exhibit band gaps of 1.73 and 2.37 eV, respectively, and show potential as PLED materials. In addition, DPP‐containing polymers with a very low band gap could be applied as potential photovoltaic materials. Copyright © 2009 Society of Chemical Industry
Effect of Lewis base coordination on boryl radical reactivity: investigation using laser flash photolysis and kinetic ESR
Authors: Lalevée Jacques , Blanchard Nicolas , Chany Anne‐Caroline , Tehfe Mohamad‐Ali , Allonas Xavier , Fouassier Jean‐Pierre
Published: April 2009

The effect of Lewis base coordination on boryl radical reactivity (L→BH where L is triethylamine, 2‐picoline, 4‐dimethylaminopyridine, quinoline and diphenyl phosphine) is examined. Direct detection of the different boryl radicals, their transient absorption spectra, their interaction with double or triple bonds, oxygen, oxidizing agent, alkyl halides and their hydrogen lability have been studied using laser flash photolysis (LFP), kinetic ESR (KESR), ESR spin trapping and MO calculations. For example, a strong decrease of both the bond dissociation energy (BDE)(BH) (33.8 kcal mol−1) and the addition rate constant to MA (1300 105 to >105 M−1 s−1) was noted when going from the triethylamine borane to the quinoline borane complex, in line with the spin delocalization (1.04 vs. 0.19). These structures are also proposed as new highly efficient co‐initiators for the acrylate photopolymerization. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of substitution of oxygen by sulfur on maltol properties
Authors: Bolechała Krzysztof , Zborowski Krzysztof K. , Żuchowski Grzegorz , Proniewicz Leonard M.
Published: April 2009

Replacing oxygen by sulfur in a maltol molecule generates a family of new very interesting ligands: thiohydroxypyrones. In this work, theoretical calculations have been performed for all possible maltol derivatives created by consecutive substitutions of oxygen atoms by sulfur. The study is focused on molecular properties of thioligands, which are important for the formation of their metal complexes and potentially useful in medicinal and environmental chemistry. Energetic, tautomeric, aromatic, and charge distribution data are reported and the results are compared with maltol properties. It is shown that, similar to maltol, the most stable tautomer for all thio derivatives, is the one with the keto‐enol group. The protonation in cations occurs always on the heteroatom of the (thio)ketone group. The study has been carried out with the aid of some aromaticity indices, such as HOMA, NICS, and ASE. Aromaticity is studied in the heterocyclic pyran ring and in the XCCX part (where X – oxygen or sulfur). All calculations were performed at the B1LYP/6‐311++G(d,p) level of theory. We conclude that the aromaticity order determined previously for maltol (cation > neutral molecule > anion) is also preserved for thiohydroxopyrones. The results of the population analysis indicate that upon protonation, a large portion of additional positive charge delocalizes on the entire molecule, whereas upon deprotonation, negative charge accumulates mainly on the heteroatoms of the XCCX group. Copyright © 2009 John Wiley & Sons, Ltd.
Antioxidant effects of phenothiazine, phenoxazine, and iminostilbene on free‐radical‐induced oxidation of linoleic acid and DNA
Authors: Liu Zai‐Qun , Tang You‐Zhi , Wu Di
Published: April 2009

Antioxidant effects of phenothiazine (PtzNH), phenoxazine (PozNH), and iminostilbene (IsbNH) on the oxidation of linoleic acid (LH) and DNA induced by 2,2′‐azobis(2‐amidinopropane) dihydrochloride (AAPH) were investigated in this work. LH was suspended in the liposome of dipalmitoyl phosphatidylcholine (DPPC) to mimic a biomembrane. In the course of AAPH‐induced oxidation of LH, the inhibition period (tinh) generated by PtzNH, PozNH, and IsbNH was proportional to the concentrations of PtzNH, PozNH, and IsbNH employed. The abilities of PtzNH, PozNH, and IsbNH to protect LH were similar to that of trolox (6‐hydroxyl‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid). Quantum chemical calculations elucidated that the nonplanar configurations of PtzNH, PozNH, and IsbNH transformed to planar ones when they were converted into radicals. In addition, spin‐densities (SDs) on the N atom in the radicals derived from PtzNH, PozNH, and IsbNH were calculated. The N atom in the radical of PtzNH possessed the lowest SD, indicating that the radical of PtzNH was the most stable one. Moreover, PtzNH, PozNH, and IsbNH were applied to protect the DNA against AAPH‐induced oxidation, in which PozNH and IsbNH were able to generate tinh. The tinh generated from PozNH and IsbNH was also proportional to their concentrations. The antioxidant effect of PozNH on the oxidation of DNA was higher than that of IsbNH. Copyright © 2009 John Wiley & Sons, Ltd.
Heterocyclic analogs of phenol as novel potential antioxidants
Authors: Shi Jing , Liang Shuang , Feng Ye‐Su , Wang Hua‐Jing , Guo Qing‐Xiang
Published: April 2009

Five density functional theory (DFT) methods including B3LYP, B3PW91, MPW1K, MPWB, TPSS1KCIS have been evaluated by comparing with the experimental OH bond dissociation enthalpies (BDEs) of substituted phenols. B3PW91 is found to be the best method, for which the calculation error was 3.62 kJ/mol. Subsequently, the BDEs (OH) of hydroxyl groups on five‐ and six‐membered heteroatomic aromatic rings have been calculated using the (RO)B3PW91/6‐311++G(2df,2p)//(U)B3LYP/6‐311g(d,p) procedure. In addition, the ionization energy (IE) and proton affinity [PA(O−)] of these compounds have also been examined. On the basis of our theoretical study, a series of imidazolols, thiazolols, and oxazolols were studied to assess their antioxidant activities. It was found that 5‐oxazolol could be a promising novel antioxidant precursor. Copyright © 2009 John Wiley & Sons, Ltd.
Higher pulmonary dead space may predict prolonged mechanical ventilation after cardiac surgery
Authors: Ong Thida , Stuart‐Killion Regan B. , Daniel Brian M. , Presnell Laura B. , Zhuo Hanjing , Matthay Michael A. , Liu Kathleen D.
Published: April 2009

Children undergoing congenital heart surgery are at risk for prolonged mechanical ventilation and length of hospital stay. We investigated the prognostic value of pulmonary dead space fraction as a non‐invasive, physiologic marker in this population. In a prospective, cross‐sectional study, we measured pulmonary dead space fraction in 52 intubated, pediatric patients within 24 hr postoperative from congenital heart surgery. Measurements were obtained with a bedside, non‐invasive cardiac output (NICO) monitor (Respironics Novametrix, Inc., Wallingford, CT). Median pulmonary dead space fraction was 0.46 (25–75% IQR 0.34–0.55). Pulmonary dead space fraction significantly correlated with duration of mechanical ventilation and length of hospital stay in the entire cohort (rs = 0.51, P = 0.0002; rs = 0.51, P = 0.0002) and in the subset of patients without residual intracardiac shunting (rs = 0.45, P = 0.008; rs = 0.49, P = 0.004). In a multivariable logistic regression model, pulmonary dead space fraction remained an independent predictor for prolonged mechanical ventilation in the presence of cardiopulmonary bypass time and ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (OR 2.2; 95% CI 1.14–4.38; P = 0.02). The area under the receiver operator characteristic curve for this model was 0.91. Elevated pulmonary dead space fraction is associated with prolonged mechanical ventilation and hospital stay in pediatric patients who undergo surgery for congenital heart disease and has additive predictive value in identifying those at risk for longer duration of mechanical ventilation. Pulmonary dead space may be a useful prognostic tool for clinicians in patients who undergo congenital heart surgery. Pediatr Pulmonol. 2009; 44:457–463. © 2009 Wiley‐Liss, Inc.
Early oxygen uptake recovery following exercise testing in children with chronic chest diseases
Authors: Stevens D. , Oades P.J. , Armstrong N. , Williams C.A.
Published: April 2009

The value of exercise testing as an objective measure of disease severity in patients with chronic chest diseases (CCD) is becoming increasingly recognized. The aim of this study was to investigate changes in oxygen uptake $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ during early recovery following maximal cardiopulmonary exercise testing (CPXT) in relation to functional capacity and markers of disease severity. Twenty‐seven children with CCD (age 12.7 ± 3.1 years; 17 female) [19 children with Cystic fibrosis (CF) (age 13.4 ± 3.1 years; 10 female) and 8 with other stable non‐CF chest diseases (NON‐CF) (age 11.1 ± 2.2 years; 7 female)] and 27 healthy controls (age 13.2 ± 3.3 years; 17 female) underwent CPXT on a cycle ergometer. On‐line respiratory gas analysis measured $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ before and during CPXT to peak $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ $({\buildrel {.} \over {\rm V}}{\rm O}_2)$peak, and during the first 10 min of recovery. Early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery was quantified by the time (sec) to reach 50% of the $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ peak value. Early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery was correlated against spirometry [forced expiratory volume in 1 sec (FEV1) and forced expiratory flow between 25% and 75% of the forced vital capacity (FEF25–75)] and aerobic fitness $({\buildrel {.} \over {\rm V}}{\rm O}_2)$peak as a measure of functional capacity. Disease severity was graded in the CF patients by the Shwachman score (SS). Compared to controls, children with CCD demonstrated a significantly reduced $({\buildrel {.} \over {\rm V}}{\rm O}_2)$peak (P = 0.011), FEV1 (P < 0.001), FEF25–75 (P < 0.001), and a significantly prolonged early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery (P = 0.024). In the CF patients the SS was significantly correlated with early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery (r = −0.63, P = 0.004), FEV1 (r = 0.72, P = 0.001), and FEF25–75 (r = 0.57, P = 0.011). In the children with CCD, FEV1, FEF25–75, and BMI were not significantly correlated with $({\buildrel {.} \over {\rm V}}{\rm O}_2)$peak or early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery. Lung function does not necessarily reflect aerobic fitness and the ability to recover from exercise in these patients. A significant relationship was found between $({\buildrel {.} \over {\rm V}}{\rm O}_2)$peak and early $({\buildrel {.} \over {\rm V}}{\rm O}_2)$ recovery (r = −0.39, P = 0.044) in the children with CCD, showing that a greater aerobic fitness corresponded with a faster recovery. Pediatr Pulmonol. 2009; 44:480–488. © 2009 Wiley‐Liss, Inc.
Association of lower airway inflammation with physiologic findings in young children with cystic fibrosis
Authors: Peterson‐Carmichael Stacey L. , Harris William T. , Goel Ruchika , Noah Terry L. , Johnson Robin , Leigh Margaret W. , Davis Stephanie D.
Published: April 2009

Background

The relationship between lower airway markers of inflammation and infection with physiologic findings is poorly understood in young children with cystic fibrosis (CF). The goal of this study was to evaluate the association of bronchoalveolar lavage fluid (BALF) markers of infection and inflammation, including mediators linked to airway remodeling, to infant lung function values in young children with CF undergoing clinically indicated bronchoscopy.

Methods

Plethysmography and the raised volume rapid thoracoabdominal compression (RVRTC) technique were performed in 16 sedated infants and young children with CF prior to bronchoscopy. BALF was collected and analyzed for pathogen density, cell count, % neutrophils, transforming growth factor beta 1 (TGF‐β1), matrix metalloproteinases (MMP), and interleukin‐8 (IL‐8).

Results

There was a significant direct correlation between functional residual capacity (FRC), the ratio of residual volume to total lung capacity (RV/TLC) and FRC/TLC with % neutrophils (P < 0.05). Forced expiratory flows were inversely correlated to % neutrophils (P < 0.01). Lung function parameters did not differentiate those with and without lower airway infection; however, pathogen density directly correlated with FRC and inversely correlated with flows (P < 0.05). In a subset of the population, MMP‐2 directly correlated with RV/TLC and inversely correlated with flows (P < 0.05) and TGF‐β1 directly correlated with FRC (P < 0.05).

Conclusions

Results from this study suggest that lower airway inflammation as well as mediators linked to airway remodeling play an active role in pulmonary deterioration in CF infants and young children undergoing clinically indicated bronchoscopy. Pediatr Pulmonol. 2009; 44:503–511. © 2009 Wiley‐Liss, Inc.
Update on the quantum properties of the supermembrane
Authors: Garcia del Moral M.P.
Published: April 2009

In this note we summarize some of the quantum properties found since the early 80's until nowdays that characterize at quantum level the spectrum of the supermembrane. In particular we will focus on a topological sector of the 11D supermembrane that, contrary to the general case, has a purely discrete spectrum at supersymmetric level. This construction has been consistently implemented in different types of backgrounds: toroidal and orbifold‐type with G2 structure able to lead to a true G2 compactification manifold. This theory has N = 1 supersymmetries in 4D. comment on the relevant points of this construction as well as on its spectral characteristics. We will also make some comments on the quantum properties of some effective formulation of multiple M2's theories recently found.
From twists and shifts to L‐R asymmetric D‐branes
Authors: Bianchi M.
Published: April 2009

In the first part of the talk, we discuss non‐geometric twists and shifts and briefly review asymmetric orbifolds and free fermion constructions. These allow us to build Type IIB models with 𝒩 = 1L + 1R and 𝒩 = 1L + 0R models having few or no moduli. We then consider unoriented projections of the former and (‘exotic’) D‐branes in the latter. In the second part, devoted to L‐R asymmetric D‐branes, we review how extended supergravity vacua in D = 4 can be embedded in Type II superstrings. We then identify bound states of D‐branes with residual susy and non‐trivial R‐R couplings. We discuss the 𝒩 = 6 = 2L + 4R case in detail and sketch other extended susy cases. Finally we describe the resulting open string excitations. We conclude with some speculations and possible interesting developments.
UV laser modification and selective ion‐beam etching of amorphous vanadium pentoxide thin films
Authors: Cheremisin Alexander , Putrolaynen Vadim , Velichko Andrey , Pergament Alexander , Kuldin Nikolay , Grishin Alexander
Published: April 2009

We present the results on excimer laser modification and patterning of amorphous vanadium pentoxide films. Wet positive resist‐type and Ar ion‐beam negative resist‐type etching techniques were employed to develop UV‐modified films. V2O5 films were found to possess sufficient resistivity compared to standard electronic materials thus to be promising masks for sub‐micron lithography. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of a conductive CaRuO3 bottom electrode for ferroelectric BaTiO3 films on a Si substrate
Authors: Paik Hanjong , Hong Jongin , Jang Yong‐oon , Park Yun Chang , Lee Jeong Yong , Song Hanwook , No Kwangsoo
Published: April 2009

A capacitor of Pt/BaTiO3/CaRuO3 (Pt/BTO/CRO) was successfully prepared on a Si substrate by using radio‐frequency (RF) magnetron sputtering. The preferentially (110)‐oriented CRO bottom electrode enabled us to obtain highly oriented BTO thin film on the Si substrate. Local epitaxy between BTO and CRO was clearly confirmed by high resolution transmission electron microscopy (HRTEM) and fast Fourier transformation (FFT) analysis. The clear interface between CRO and BTO without any Si diffusion and silicate formation was determined by Auger electron spectroscopy (AES). The polarization value (2Pr) of 6 μC/cm2, the coercive field (2|Ec|) of 61 kV/cm and the stable current density of 1 × 10–8 A/cm2 around 2100 kV/cm electric field were obtained. Its tunability on CRO was reached up to 0.52 with a loss tangent less than 0.09 at room temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study on the photoluminescence of Cr3+ and doping mechanism in F– codoped PbWO4 single crystal
Authors: Li Weifeng , Long Yumei , Feng Xiqi , Zhao Jingtai
Published: April 2009

The influence of Cr3+ and F– codoping on the defect structures in PbWO4 crystal is investigated by X‐ray diffraction and Fourier transform infrared (FTIR) spectroscopy and consequently a doping mechanism is proposed that the Cr3+ ions predominantly occupy the W6+ sites due to the help of F–. Photoluminescence (PL) spectra of PWO:Cr,F demonstrates in addition to the intrinsic luminescence from the PbWO4 crystal, a new sharp emission band at 15500 cm–1 can be observed even at room temperature and it may originate from the spin‐forbidden 2E → 4A2 radiation of Cr3+ in a strong crystal field. It suggests that the F– codoping makes a large contribution to the 2E → 4A2 luminescence of Cr3+ in the scheelite‐structural PWO single crystal. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly sensitive spin‐valve devices for chip‐cytometers
Authors: Roh Jong Wook , Son Oh‐Taek , Lee Young Tack , Lee Kyoung‐il , Jung Hyo‐Il , Lee Wooyoung
Published: April 2009

The highly sensitive spin‐valve devices integrated with a microfluidic channel have been studied for cell counting in a chip‐cytometer. The presence or absence of a single magnetic bead was successfully detected by direct measurement of fringe fields emanating from magnetic beads using spin‐valve devices. The real‐time detection was also successfully confirmed by the direct measurement of magnetic fields generated from the magnetic beads passing an active sensing area of a spin‐valve device integrated with a microfluidic channel. Our results show the possibility of implementing a chip‐cytometer for biological applications using the highly sensitive spin‐valve devices integrated with a microfluidic device. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure of hydrogenated amorphous Si1–xNx thin films using soft X‐ray emission and absorption measurements
Authors: Boyko Teak , Kasap Safa , Johanson Robert , Kobayashi S. , Aoki T. , Moewes Alexander
Published: April 2009

Hydrogenated amorphous silicon nitride thin films (a‐Si1–x Nx:H) with x = 0.46, 0.54, 0.55 and 0.58 have been studied. The optical bandgaps of these materials were 2.41, 2.78, 3.29 and 3.85 eV and Urbach edge bandgaps were 2.80, 3.27, 3.85 and 4.04 eV (W. C. Tan et al., J. Mater. Sci., Mater. Electron. 20, S15–S18 (2009) [1]), respectively. The bandgaps determined in this work using soft X‐ray spectroscopy (SXS) are 3.92, 4.43, 5.18 and 5.36 ± 0.25 eV. These large bandgaps are most likely due to the surface sensitivity of the SXS measurements and possible oxidation of the films. The conduction and valence band edges are determined using a linear regression fit and the bandgaps show a similar trend to that of the optical bandgap. Using Density Functional Theory (DFT) calculations for the two crystalline phases of silicon nitride the core hole interaction is accounted for in these bandgap determinations. This shows that both N and Si states are involved in bandgap transitions. Comparison of amorphous SXS spectra with that of crystalline phases shows that the Si bonding environment is similar to that of the beta phase while the N bonding environment is similar to that of the gamma phase. This shows there is a degree of short range order in the films similar to that of α,β‐Si3N4 indicating tetrahedral SiN4. The spectra also show that the Si states with 3s‐symmetry decrease as a function of nitrogen concentration which is evidence of Si–Si bonds that would increase the Si 3s states. This increase in Si 3s‐states effectively decreases the bandgap. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electroluminescence in plasma ion implanted silicon
Authors: Desautels Phillip R. , Bradley Michael P. , Steenkamp J. T. , Mantyka James
Published: April 2009

Electroluminescent silicon is very desirable for its potential applications in computing and telecommunications. Plasma Ion Implantation (PII) is a means to modify the surface and sub‐surface properties of silicon to produce luminescent centres. Silicon to be treated with PII is immersed in low‐temperature plasma and biased to a high, negative voltage; this accelerates ions into the sample and implants them beneath its surface. The material is subsequently annealed in a furnace and fitted with thin gold and aluminium contacts. Samples of crystalline silicon were implanted with H ions, C ions, and N ions and found to emit visible light when subjected to electric current. Nearly every sample emitted light at ∼460 nm and ∼630 nm; these luminescence bands are commonly observed in X‐ray excited optical luminescence studies of silicon nanostructures and have been attributed to silicon dioxide (SiO2) and the silicon‐SiO2 interface, respectively [1]. Other luminescent bands may be the product of nanostructures and defects created by the implantation process and subsequent annealing. This presentation will explore in detail the results of these experiments and the potential of PII for modifying the luminescent properties of elemental silicon. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rabi oscillations and photocurrent in quantum‐dot tunnelling junctions
Authors: Fainberg Boris , Nitzan Abraham
Published: April 2009

Motivated by the experiments by Zrenner et al. [Nature 418, 612 (2002)], we study the influence of relaxation processes on converting Rabi oscillations in a strongly biased single‐quantum‐dot photodiode into deterministic photocurrents. We show that the behavior of a quantum dot with different tunnel rates for electron and holes is qualitatively different from that with the equal tunnel rates: in the latter case the current shows attenuating oscillations with the Rabi frequency. In contrast, for different electrons and holes tunnelling rates, the frequency of these oscillations diminishes, and they disappear beyond a definite asymmetry threshold. We give an analytical solution of the problem and a numerical example showing a different behaviour of the transferred charge in the small attenuation limit for equal and different tunnel rates for electrons and holes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of thick metal nanohole arrays fabricated by electron‐beam and nanosphere lithography
Authors: Hajiaboli Ahmad Reza , Cui Bo , Kahrizi M. , Truong Vo‐Van
Published: April 2009

Optically thick metallic nanohole structures were fabricated using two different methods – electron‐beam and nanosphere lithography. The nanosphere lithography technique was based on self‐assembling of polystyrene or silica nanospheres (0.560–1.25 μm in diameter) followed by the deposition of a silver film. The holes size and periodicity of the patterns as well as optical properties (transmission and reflection in the Visible–NIR) of the structures were investigated. The extraordinary optical transmission (EOT) was studied experimentally in both structures and it was found to be dependent on the geometrical parameters (holes shape, diameter and periodicity of structures). As the samples were made for long range order, the effect of the defects like missing holes, change of periodicity or variation of the holes shape, were also studied. The experimental results, especially the position of the SPR band in the different nanohole structures, were compared with those found by simulation carried out with 3D FDTD (finite difference time domain). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Controlling the optical properties of nanostructured TiO2 thin films
Authors: Hawkeye Matthew M. , Brett Michael J.
Published: April 2009

We have studied the optical properties of nanostructured TiO2 films and demonstrated the ability to tune the refractive index of the material over a wide range. The nanostructured films are fabricated using glancing angle deposition, which provides the ability to precisely control the density of the deposited film. Film morphology was examined using scanning electron microscopy and the films were optically characterized by polarized‐reflectance measurements. A simple isotropic homogeneous model, which is shown to be a good approximation of the film, is used to determine the optical constants from the reflectance measurements. Improvements to the model are suggested. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)