bluuebunny/crossref_metadata_2025 huggingface dataset:
Cognition and depression: the effects of fluvoxamine, a sigma‐1 receptor agonist, reconsidered
Authors: Hindmarch Ian , Hashimoto Kenji
Published: March 2010

Cognitive impairment is a primary feature of patients with major depressive disorder (MDD) and is characterised by stress‐induced neural atrophy. Via alpha‐adrenergic, anti‐cholinergic and anti‐histaminic activities, several antidepressants can cause significant counter‐therapeutic cognitive impairment. Evidence is emerging of the involvement of sigma‐1 receptor agonism in the mechanism of action of some antidepressants, notably fluvoxamine. Sigma‐1 receptors are abundant in areas affected by depression/stress‐induced cerebral atrophy and their ligands have a unique pharmacological profile; they may promote neurogenesis and initiate adaptive neural plasticity as a protection/reaction to stress. Fluvoxamine, as a potent sigma‐1 receptor agonist, has shown ameliorating effects in animal models of psychosis, depression, stress, anxiety, obsessive‐compulsive disorder (OCD) and aggression and has been shown to improve cognitive impairments. In humans, fluvoxamine may repair central nervous system (CNS) atrophy and restore cognitive function. The current review explores the mechanisms through which sigma‐1 receptors can modulate cognitive function and examines how antidepressant therapy with fluvoxamine may help improve cognitive outcomes in patients with depression. Copyright © 2010 John Wiley & Sons, Ltd.
Impact of the novel antidepressant agomelatine on disturbed sleep–wake cycles in depressed patients
Authors: Quera‐Salva Maria‐Antonia , Lemoine Patrick , Guilleminault Christian
Published: March 2010

Background

Disturbance of sleep–wake cycles is common in major depressive disorder (MDD), usually as insomnia, but also as hypersomnia or reduced daytime alertness. Agomelatine, an MT1 and MT2 receptor agonist and 5‐HT2C receptor antagonist, represents a novel approach in MDD, with proven antidepressant efficacy and a positive impact on the sleep–wake cycle. We review the effects of agomelatine 25/50 mg/day on objective and subjective measures of the sleep–wake cycle in MDD.

Subjective measures

Agomelatine improved all aspects of the sleep–wake cycle from as early as 1 week in randomized trials versus selective serotonin reuptake inhibitors and venlafaxine, particularly getting off to sleep and quality of sleep, with an improvement in daytime alertness.

Objective measures

Agomelatine's effect on sleep architecture in MDD has been measured by polysomnography (PSG). There were significant improvements in sleep efficiency, slow‐wave sleep (SWS), and the distribution of delta activity throughout the night, but no change in amount or latency of rapid eye movement (REM) sleep. Furthermore, the slow‐wave sleep was resynchronized to the first sleep cycle of the night.

Conclusion

Agomelatine, a novel antidepressant, improves disturbed sleep–wake cycles in MDD. The improvement of both nighttime sleep and daytime functioning with agomelatine are promising features of this antidepressant regarding the management of MDD. Copyright © 2010 John Wiley & Sons, Ltd.
Combining keratinocyte growth factor transfection into the airways and tracheal occlusion in a fetal sheep model of congenital diaphragmatic hernia
Authors: Saada Julien , Oudrhiri Noufissa , Bonnard Arnaud , de Lagausie Pascal , Aissaoui Abderrahim , Hauchecorne Michelle , Oury Jean‐François , Aigrain Yves , Peuchmaur Michel , Lehn Jean‐Marie , Lehn Pierre , Luton Dominique
Published: March 2010

Background

In utero tracheal occlusion (TO) has been developed to improve the lung hypoplasia associated with congenital diaphragmatic hernia (CDH). However, although TO stimulates fetal lung growth, it results in a decrease of alveolar type II cells (ATII) and surfactant production. Because keratinocyte growth factor (KGF) is a potent stimulus of ATII proliferation and maturation, we evaluated, in a fetal lamb model of CDH, a gene therapy strategy combining TO and ovine KGF transfection into the fetal airways using bisguanidinium‐tren‐cholesterol/dioleoyl‐phosphatidylethanolamine (BGTC/DOPE) cationic liposomes.

Methods

Three groups of sheep fetuses with CDH and a group of normal fetuses were studied. The fetuses of the three groups with CDH (KGF, Medium and Hernia groups) underwent surgery at 85 days of gestation to create a diaphragmatic hernia. The KGF and medium group fetuses underwent a second surgery step at day 125 to perform TO associated with injection of the KGF transfection mixture (KGF group) or control medium (Medium group), whereas the fetuses of the Hernia group were left untreated. Normal fetuses were used as a control (Normal group). All fetuses were euthanized at 132 days of gestation and various analytical studies [lung weight, radial alveolar count (RAC), KGF and surfactant protein B (SPB) expression, number of ATII cells] were performed to assess the efficiency of KGF transfection and its effects on fetal lung development.

Results

TO was associated with lung hyperplasia and increased RAC in the Medium and KGF groups versus the Hernia group. Expression of KGF was increased in the KGF group compared to all other groups and was associated with an increased synthesis of SPB by alveolar cells and an ectopic synthesis of SPB by bronchiolar cells compared to TO treatment alone.

Conclusions

Thus, BGTC/DOPE liposomes can mediate efficient KGF transfection into the airways in a fetal sheep model of CDH. Furthermore, combining KGF transfection and TO resulted not only (as did TO alone) in the correction of the CDH‐associated lung hypoplasia and decreased RAC, but also in increased SPB synthesis, suggesting a better maturation of the re‐growing lung (compared to TO alone). Additional studies are required to further explore the therapeutic potential of such a combined strategy; in particular, studies evaluating the lung function of in utero‐treated CDH lamb newborns. Copyright © 2010 John Wiley & Sons, Ltd.
Differential antitumor effect of interleukin‐12 family cytokines on orthotopic hepatocellular carcinoma
Authors: Lo Chia‐Hui , Chang Chia‐Ming , Tang Shih‐Wen , Pan Wen‐Yu , Fang Cheng‐Chieh , Chen Yin , Wu Ping‐Yi , Chen Kai‐Yun , Ma Hsin‐I , Xiao Xiao , Tao Mi‐Hua
Published: March 2010

Background

Hepatocellular carcinoma (HCC) is one of the most difficult cancers to treat. The interleukin (IL)‐12 family cytokines, including IL‐12, IL‐23 and IL‐27, display overlapping, but not redundant, roles in regulating lymphocyte subpopulations. IL‐12 is known as a potent antitumor cytokine, whereas the results of the antitumor effect of IL‐23 and IL‐27 are inconsistent. The present study aimed to directly compare the relative antitumor efficacy of these three IL‐12 family cytokines on HCC.

Methods

A murine orthotopic BNL HCC model, in which the tumor is located in an environment heavily populated with different lymphocyte subsets, was established. The hepatotropic adeno‐associated virus serotype 8 (AAV8) vector was used to deliver the cytokine genes aiming to achieve sustained cytokine expression in the liver.

Results

AAV8/IL‐12 treatment significantly reduced hepatic metastases and prolonged survival time, whereas treatment with AAV8/IL‐23 or AAV8/IL‐27 had only moderate antitumor effects at a high dose. The antitumor efficacy of these cytokines was positively correlated with their ability to regulate hepatic T cells, natural killer cells and natural killer T cells, with IL‐12 greatly increasing the number and activation status of these cells, whereas IL‐27 had no effect and IL‐23 had a negative effect. AAV8/IL‐12 treatment also resulted in a marked decrease in tumor vessel density, which was not observed with AAV8/IL‐23 and AAV8/IL‐27 treatment.

Conclusions

The data obtained in the present study highlight the importance of local lymphocytes and anti‐angiogenesis for influencing the antitumor activity of these three IL‐12 family cytokines and suggest that IL‐12 is the best candidate for treating HCC. Copyright © 2010 John Wiley & Sons, Ltd.
Agricultural innovation and food security in Sub‐Saharan Africa: Tracing connections and missing links
Authors: Mugwagwa Julius T. , Wamae Watu , Outram Simon M.
Published: March 2010

Grounded in research carried out by researchers investigating different aspects of technological and institutional innovation in agriculture in Sub‐Saharan Africa (SSA), this special issue seeks to make a contribution to empirical evidence and literature on agricultural innovation globally. The contributors explore the relationship between technology, policy and public engagement approaches and wider concepts of technology development and governance, and collectively argue for a broadened perspective on innovation towards generating new ways of thinking that can ultimately improve upon existing practices in the quest for sustainable solutions to food insecurity. Overall, this is not a negative story. Instead of the now common despair about the abilities of Africa to meet it is own food‐security requirements, this issue presents articles which demonstrate how much is already in place, with reflections and suggestions on how such resources can be made to work together for the greater socio‐economic good of the continent Copyright © 2010 John Wiley & Sons, Ltd.
What do complex adaptive systems look like and what are the implications for innovation policy?
Authors: Hall Andy , Clark Norman
Published: March 2010

This paper explores the use of complex adaptive systems theory in development policy analysis using a case study drawn from recent events in Uganda. It documents the changes that took place in the farming system in Soroti district during an outbreak of African cassava mosaic virus disease (ACMVD) and the subsequent decline in cassava production—the main staple food in the area. Resultant adaptation impacts are analysed across cropping, biological, economic and social systems each of which operate as an interlinked sub‐systems. The policy implications of this story suggest a policy agenda that recognises adaptation capacity as the life blood of complex adaptive systems. Since these types of system are found in all realms of human activity, it follows that strengthening this capacity is a key developmental priority that requires linking together new configurations of actors and resources to tackle an ever changing set of contexts. Copyright © 2010 John Wiley & Sons, Ltd.
Radiosynthesis and in vivo evaluation of a F‐18‐labeled pancreatic islet amyloid inhibitor
Authors: Pathuri Gopal , Agashe Hrushikesh B. , Awasthi Vibhudutta , Gali Hariprasad
Published: March 2010

Formation of islet amyloid deposits contributes to the progressive loss of beta‐cells in Type 2 diabetes. Islet amyloid is composed of islet amyloid polypeptide (IAPP). [(N‐Me)G24, (N‐Me)I26]hIAPP(22–27) peptide was found to bind human IAPP with high‐affinity and inhibit fibrillogenesis. We labeled [(N‐Me)G24, (N‐Me)I26]hIAPP(22–27) with fluorine‐18 using N‐succinimidyl‐4‐[18F]fluorobenzoate. Results from biodistribution studies in healthy CF‐1 mice at 1 h p.i. indicated that 18F‐peptide was cleared efficiently (0.04±0.02%ID/g remained in blood). The primary route of clearance from the body appears to be hepatobiliary. Radioactivity accumulation in liver, intestine, and kidney was 6.7±2.9, 60.3±18.5, and 0.2±0.0%ID, respectively. Other organs accumulated negligible radioactivity. As normal mice do not develop pancreatic amyloid deposits, only background radioactivity was seen in pancreas. The radio‐HPLC analysis of mouse urine at 2 h p.i. showed that ∼29.3% of injected 18F‐peptide excreted intact along with two additional metabolite peaks. Dynamic microPET/CT imaging of a CF‐1 mouse injected with 18F‐peptide indicated that radiotracer was rapidly taken up by liver and most of it moved into intestine within 10 min. The results provide a useful insight into the biological disposition of [(N‐Me)G24, (N‐Me)I26]hIAPP(22–27) that is being developed as a pancreatic amyloid inhibitor. Copyright © 2010 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy for trace‐level detection of explosives
Authors: Botti S. , Cantarini L. , Palucci A.
Published: March 2010

The detection of explosives and their associated compounds for security screening is an active area of research and a wide variety of detection methods are involved in this very challenging area. Surface‐enhanced Raman scattering (SERS) spectroscopy is one of the most sensitive tools for the detection of molecules adsorbed on nano‐scale roughened metal surface. Moreover, SERS combines high sensitivity with the observation of vibrational spectra of species, giving complete information on the molecular structure of material under study. In this paper, SERS was applied to the detection of very small quantities of explosives adsorbed on industrially made substrates. The spectra were acquired with a compact Raman spectrometer. Usually, a high signal‐to‐noise (S/N) spectrum, suitable for identification of explosive molecules down to few hundreds of picograms, was achieved within 30 s. Our measurements suggest that it is possible to exploit SERS using a practical detection instrument for routine analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Kinetic investigation of aquation of some Fe(II) Schiff base amino acid complexes
Authors: Nassr Lobna Abdel‐Mohsen Ebaid
Published: March 2010

Kinetics of aquation of some Fe(II) Schiff base amino acid complexes was followed spectrophotometrically. The Schiff base ligands were derived from salicylaldehyde and isoleucine, leucine, serine, methionine, tryptophan, or histidine. The reaction was studied in aqueous media, aqua–propanol mixtures, and in the presence of different concentrations of KBr. Moreover, the activation parameters were calculated and discussed for structures and other physical properties observed. The reaction was acid catalyzed and the general rate equation was suggested as follows: rate = kobs [complex], where kobs = k2 [H+]. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 372–379, 2010
Regulation of the G2/M transition in rodent oocytes
Authors: Downs Stephen M.
Published: March 2010

Regulation of maturation in meiotically competent mammalian oocytes is a complex process involving the carefully coordinated exchange of signals between the somatic and germ cell compartments of the ovarian follicle via paracrine and cell–cell coupling pathways. This review highlights recent advances in our understanding of how such signaling controls both meiotic arrest and gonadotropin‐triggered meiotic resumption in competent oocytes and relates them to the historical context. Emphasis will be on rodent systems, where many of these new findings have taken place. A regulatory scheme is then proposed that integrates this information into an overall framework for meiotic regulation that demonstrates the complex interplay between different follicular compartments. Mol. Reprod. Dev. 77: 566–585, 2010. © 2010 Wiley‐Liss, Inc.
Molecular cloning and expression analysis of Fshr and Lhr in relation to Fshb and Lhb subunits during the period of temperature‐dependent sex determination in pejerrey Odontesthes bonariensis
Authors: Shinoda Takahiro , Miranda Leandro A. , Okuma Kozue , Hattori Ricardo S. , Fernandino Juan I. , Yoshizaki Goro , Somoza Gustavo M. , Strüssmann Carlos A.
Published: March 2010

In this study, we cloned and characterized the follicle stimulating hormone receptor (Fshr) and luteinizing hormone receptor (Lhr) cDNAs of pejerrey Odontesthes bonariensis, a species with temperature‐dependent sex determination (TSD), and analyzed their expression in relation to Fshb and Lhb subunits during gonadogenesis at temperatures producing only females (17°C, FPT), both sexes (25°C, MixPT), and only males (29°C, MPT). The pejerrey Fshr cDNA had 3,069 bp for a mature protein of 694 amino acids (aa) and a signal peptide of 22 aa; the Lhr cDNA had 2,936 bp for a mature protein of 676 aa and a signal peptide of 25 aa. With the exception of Lhr in fish at the MPT, all genes showed significant increases and/or peaks of expression before histological differentiation of the gonads regardless of temperature. Larvae at the FPT had lower Fshb and Lhb but higher Lhr expression during the TSD period than those at the MPT; a clear pattern could not be ascertained for Fshr. At the MixPT, Fshb, Lhb, and Lhr mRNA increased in approximately half of the fish during TSD and sex differentiation and the sex ratio was 55.2% male. Based on the above results, it is suggested that animals with high Fshb and Lhb and low Lhr values represent putative males. These evidences, together with other studies, suggest that temperature may signal through the pituitary (differential expression of Fshb and Lhb) down to the gonads (differential expression of Lhr), probably affecting the regulation of steroidogenesis during the TSD process of pejerrey. Mol. Reprod. Dev. 77: 521–532, 2010. © 2010 Wiley‐Liss, Inc.
Constitutive modeling of rubberlike materials based on consistent strain energy density functions
Authors: Darijani H. , Naghdabadi R. , Kargarnovin M.H.
Published: March 2010

Rubberlike materials are characterized by high deformability and reversibility of deformation. From the continuum viewpoint, a strain energy density function is postulated for modeling the behavior of these materials. In this paper, a general form for the strain energy density of these materials is proposed from a phenomenological point of view. Based on the Valanis‐Landel hypothesis, the strain energy density of incompressible materials is expressed as the sum of independent functions of the principal stretches meeting the essential requirements on the form of the strain energy density. It is cleared that the appropriate mathematical expressions for constitutive modeling of these materials are polynomial, logarithmic, and particularly exponential functions. In addition, the material parameters are calculated using a novel procedure that is based on the correlation between the values of the strain energy density (rather than the stresses) cast from the test data and the theory. In order to evaluate the performance of the proposed strain energy density functions, some test data of rubberlike materials with pure homogeneous deformations are used. It is shown that there is a good agreement between the test data and predictions of the models for incompressible isotropic materials. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Rotational molding of polycarbonate reinforced polyethylene composites: Processing parameters and properties
Authors: Liu Shih‐Jung , Peng Kang‐Ming
Published: March 2010

Rotational molding has become one of the most important polymer processing methods for producing hollow plastic articles. The goal of this report is to study the rotational molding of polycarbonate (PC) reinforced polyethylene composites. Experiments were carried out on a laboratory scale uniaxial machine, which is capable of measuring internal air temperatures in the cycle. Before molding, PC and polyethylene were blended by a twin‐screw extruder. The extrudate was cut into pellets. Polyethylene powder mixed with PC/polyethylene pellets were then mixed by a dry mixer and rotationally molded by a box mold. Characterization of molded part properties was performed after molding. It was found that the impact strength of molded composites increased with the volume fraction of PC reinforcement, whereas the tensile strengths decreased with the reinforcement. Higher cooling rates molded composites with higher impact strengths but lower tensile strengths. There exists an optimum internal peak air temperature with which composites of the highest mechanical properties can be obtained. Additionally, various mathematical models were employed to predict the tensile properties of molded composites, and the Halpin–Tsai–Nielsen model was found to match well with the measured tensile modulus of molded composites. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Process of grafting styrene onto LLDPE by swelling and suspension copolymerization
Authors: Yan Jing , Miao Xiaojie , Cui Xuejun , Jin Weiqun , Liang Hongwei , Li Junfeng , Wang Hongyan
Published: March 2010

A technology of swelling and suspension copolymerization was conducted to graft styrene onto linear low‐density polyethylene (LLDPE). The graft mechanism of styrene with LLDPE had been described by 1H NMR and IR. The mean particle diameter and size distribution of the products with different proportions of LLDPE to styrene monomer were calculated. The morphology and thermal behavior of copolymers were characterized by scanning electron microscopy and differential scanning calorimetry. The glass transition temperature of copolymers increased with the addition of LLDPE, which proved the existence of the polyethylene‐g‐polystyrene copolymer. The grafting efficiency and granulation rate of suspension copolymerization were investigated. It was found that the grafting efficiency increased and the granulation rate decreased with the addition of LLDPE. POLYM. ENG. SCI., 50:1713–1720, 2010. © 2010 Society of Plastics Engineers
Crystallization and biodegradation of polylactide/carbon nanotube composites
Authors: Wu Defeng , Wu Liang , Zhou Weidong , Zhang Ming , Yang Tao
Published: March 2010

The crystallization behavior of polylactide/carbon nanotube composites was studied using differential scanning calorimeter and polarized optical microscope. The nucleation mechanisms and the crystallization kinetics were explored. The results show that the presence of nanotubes has nucleating effect on both the melt crystallization and the cold crystallization of PLA. However, the nanotubes also play the role of physical barrier, impeding the crystal growth dynamically. In the experimental range of temperatures, the presence of nanotubes accelerates the melt crystallization, while retards the overall kinetics of the cold crystallization. The biodegradability of the samples with various crystallization histories was then further examined. The results show that the presence of nanotubes reduces the biodegradation rate of PLA, and the amorphous sample shows the highest degradation levels. Moreover, a lower degradation level is observed both on the surface and inside the sample with melt crystallization history in contrast to the one with cold crystallization history. POLYM. ENG. SCI., 50:1721–1733, 2010. © 2010 Society of Plastics Engineers
Poly(acrylonitrile‐co‐vinyl acetate)/Ag composite microspheres: One‐pot fabrication and application as catalyst
Authors: Xiao Hongping , Xia Youyi
Published: March 2010

Waxberry‐like poly(acrylonitrile‐co‐vinyl acetate)/Ag composite microspheres have been prepared simply and directly via a one‐step self‐assembly approach. The morphology, formation, and catalytic activity of the as‐prepared composite microspheres are further investigated. The difference in the solubility among different segments of poly(acrylonitrile‐co‐vinyl acetate) is the basis of the formation of poly(acrylonitrile‐co‐vinyl acetate) microspheres, while the CN groups on the surface of poly(acrylonitrile‐co‐vinyl acetate) microspheres play an important role in the growth process from poly(acrylonitrile‐co‐vinyl acetate) microsphere to poly(acrylonitrile‐co‐vinyl acetate)/Ag composite microsphere. It is found that bulk quantities of composite microspheres with high density of Ag nanoparticles on the surface can be obtained readily by controlling the concentration of AgNO3. The as‐prepared composite microsphere exhibits excellent catalytic activity on reduction of p‐nitrophenol. This study may shed some light on the self‐assembly of other metal/polymer composite microspheres. POLYM. ENG. SCI., 50:1767–1772, 2010. © 2010 Society of Plastics Engineers
A theoretical model of concurrent longitudinal and circumferential superdrawing of hollow polyethylene terephthalate fibers
Authors: Wang Youjiang , Aneja Arun Pal
Published: March 2010

In a superdrawing process, a polyethylene terephthalate (PET) filament is elongated without developing much orientation and crystallization. Exploiting this phenomenon may bring about lower cost, more flexible and faster response in synthetic fiber production. The concurrent longitudinal and circumferential superdrawing phenomenon of PET hollow fibers is explained using the viscoelastic behavior of a thick walled cylinder under an internal pressure and an axial load in a continuous process. The model defines the stress–strain‐displacement relationship of hollow fibers. The fiber undergoes instantaneous radial superdrawing (increase in thickness) in the process zone followed by concurrent circumferential (increase in void) and longitudinal (increase in length) superdrawing. Based on material viscoelastic properties and processing conditions, the model predicts the threadline tension, internal pressure, and final fiber geometries. Excellent agreement of the model with experimental results is observed over a range of processing conditions. The model is developed from a process engineering viewpoint to enable the analysis of the impact of process parameters during superdrawing on fiber properties. POLYM. ENG. SCI., 50:1773–1779, 2010. © 2010 Society of Plastics Engineers
Thermomechanical properties of virgin and recycled polypropylene impact copolymer/CaCO3 nanocomposites
Authors: Elloumi A. , Pimbert S. , Bourmaud A. , Bradai C.
Published: March 2010

The effect of successive injection moldings on the thermal, rheological, and mechanical properties of a polypropylene impact copolymer (PP) was investigated. The crystal content decreased as the molecular weight decreased due to chain scission with repeated injection molding. The Young modulus and the yield stress remained constant, despite a drop in the strain to break. Virgin and recycled PP matrix were filled with nanosized calcium carbonate (CaCO3) particles. The effect of morphology on the thermal and mechanical properties of nanocomposites of virgin and recycled PP filled with nanosized CaCO3 particles was also studied. The mechanical properties of the nanocomposites were strongly influenced by the intrinsic toughness of the matrix and the concentration and dispersion of the filler. The yield strength and strain of virgin PP decreased gradually, while its Young's modulus increased slightly with increasing CaCO3 loading. These phenomena were less pronounced for the recycled matrix. Incorporation of nanoparticles to virgin matrix produced an increase in tensile stiffness and ductility, when good dispersion of the filler was achieved. However, the impact strength dropped dramatically for high filler contents. A significant increase in impact strength was observed for the recycled PP. POLYM. ENG. SCI., 50:1904–1913, 2010. © 2010 Society of Plastics Engineers
Studies on the melt spinning process of noncircular fiber by numerical and experimental methods
Authors: Zhou Ji , Li Jian , Yu Wei , Li Xin , Zhou Chixing
Published: March 2010

The spinning process of noncircular fiber was investigated in this work. A combination of numerical simulations and experiments made it possible to find out the optimum processing condition for shaped fiber. First, an inverse method which combined two‐dimensional/three‐dimensional simulation with experiments was utilized to find out the temperature and draw ratio dependent surface tension in melt spinning of shaped fiber. The surface tension as a function of temperature and draw ratio was found to be decisive to the change of cross‐section. Second, an orthogonal numerical experiment and statistics analysis were carried out to determine the optimum spinning condition for the desired noncircular fiber. The optimum spinning condition was well validated by experiments. It was then proved that the integrated method in this work, including the numerical method, the inverse method to determining the surface tension, and the orthogonal analysis, can be a good solution for the design and processing of profiled fibers. POLYM. ENG. SCI., 50:1935–1944, 2010. © 2010 Society of Plastics Engineers
Identification of candidate material systems for quantum dot solar cells including the effect of strain
Authors: Dahal Som N. , Bremner Stephen P. , Honsberg Christiana B.
Published: March 2010

Heterostructures that include self‐assembled quantum dots (SAQDs) have been suggested as model systems for the realization of novel high efficiency solar cells such as those based on intermediate bands (IBs). The lattice mismatch in the epitaxial growth of these structures, necessary for the formation of SAQDs, introduces strain throughout the structure, making the selection of materials systems with appropriate physical parameters problematic. The model solid theory is used to calculate the energy band edge alignment at Γ point of such quantum dot (QD) heterostructures including the effects of strain. With the modified band gaps due to strain, a materials search was performed for high efficiency QD solar cells among III‐V binaries and ternaries with negligible valence band offsets. This requirement of the valence band offset along with the limited band gap ranges for optimum efficiency results in only a few feasible materials systems being identified. The optimum barrier/dot material system found was Al0.57In0.43As/InP0.87Sb0.13grown on lattice matched metamorphic buffer layer, but due to miscibility gap concerns it is suggested that the Al0.50In0.50As/InAs0.41P0.59fully strained system may be preferred. Copyright © 2010 John Wiley & Sons, Ltd.
Reaction pathway of aliphatic pinacol‐type rearrangement reexamined
Authors: Itoh Shuhei , Yamataka Hiroshi
Published: March 2010

Pinacol rearrangement is often written to proceed via 1,2‐Me migration to the tertiary cationic center, followed by deprotonation to give pinacolone. Computational study was carried out for model reactions to clarify why the migration of the OH group is not involved in the mechanistic scheme despite the fact that OH is a better migrating group than Me. It was found that the migratory aptitude of X in both XCMe2‐CH2Cl and XCMe2‐CMe2Cl is in the order, NH2 > OMe > Ph > Me, indicating that a migrating group with n‐electrons has a larger aptitude than a π‐ or σ‐electron group. However, the reactivity differences became much smaller for XCMe2‐CMe2OMe, a model compound for aliphatic pinacol rearrangement. Calculations of MeOCMe2‐CMe2OMe revealed that three initial ionization steps, CO heterolysis, concerted OMe migration and concerted Me migration, compete with each other. On the other hand, the ring‐opening step of the epoxide‐type intermediate formed via OMe migration was shown to have quite a large activation barrier. It was suggested that aliphatic pinacol rearrangement proceeds via the concerted Me migration route or the CO heterolysis‐Me migration‐deprotonation route. Epoxide may form by the concerted MeO migration, but it would not be an important intermediate of pinacol rearrangement. Copyright © 2010 John Wiley & Sons, Ltd.
Photochromism of dihydroindolizines: part XIV. Synthesis and photophysical behavior of photochromic dihydroindolizine‐tripodal linkers toward anchoring sensitizers to semiconductor nanoparticles
Authors: Ahmed Saleh Abdel‐Mgeed , Al‐Raqa Shaya Y.
Published: March 2010

Photochromic dihydroindolizines (DHIs) 4a,5‐dihydropyrrolo[1,2‐b]pyridazine based tripodal‐linker systems with adamantane core and ethyl benzoate tripods as anchoring groups have been successfully synthesized. In addition, new spirocyclopropene precursors have been prepared through both chemical and photochemical processes. The photochromic properties of the newly synthesized DHIs derivatives have been optimized and fine‐tuned by the incorporation of various substituents on the fluorene (region A) and pyridazine (region C) moieties. Several alternative routes for the synthesis of the DHIs under investigation have been established. The Sonogashira crosscoupling reaction was utilized for fragment coupling between DHIs and the phenylacetylene tether of the adamantane core. Several reaction conditions of this key reaction were surveyed to obtain optimal yields of a new series of coupling products targeted for anchoring to semiconductor nanoparticles. The chemical structures of the newly synthesized materials were elucidated by both analytical and spectroscopic tools. Irradiation of the photochromic DHIs with polychromatic light resulted in ring opened colored betaines which underwent cycloreversion reactions via thermal 1,5‐electrocyclization processes. The kinetic of the thermal 1,5‐electrocyclization was studied by using a UV/VIS/NIR spectrophotometer. The kinetic measurements showed the half‐lives of the colored betaines to be in the second domain. A pronounced increase in the half‐lives of betaines bearing dimethyl‐substituted pyridazine was noted compared with non‐substituted pyridazine betaines. A strong effect of solvent polarity on the λmax and half‐lives of the betaines was observed. The further adjustment of the absorption maxima and the kinetic properties via the manipulation of substituents on the fluorene (region A) and pyridazine moieties (region C) should yield more refined systems for application as supports onto metal‐oxide surfaces which remains an active area of our ongoing research. Copyright © 2010 John Wiley & Sons, Ltd.
On the origin of the chemical barrier and tunneling in enzymes
Authors: Machleder Sara Quaytman , Pineda J.R. Exequiel T. , Schwartz Steven D.
Published: March 2010

This paper presents both a review of some recent results from our group and experimental groups, and some new theoretical results all of which are helping to form a more physically rigorous picture of the process of enzymatic catalysis. A common classical picture of enzymatic catalysis is the transition state tight binding model. Schwartz and Schramm (Nat. Chem. Biol. 2009, 5, 551–558.) have recently argued from both theoretical and experimental results that this picture is incorrect. We now investigate what the nature of barriers might be in enzymatic reactions, and what this viewpoint might imply for tunneling in a hydrogen transfer enzyme. For lactate dehydrogenase we conclude that the enzymes role in catalysis is at least partially to hunt through configuration space for those configurations that minimize chemical free energy barriers. Those configurations do not seem to be stable basins on the free energy surface, and in fact the overall free energy barrier to reaction may well largely be due to this stochastic hunt—both probabilistically and energetically. We suggest further computations to test this hypothesis. Copyright © 2010 John Wiley & Sons, Ltd.
The International Linear Collider
Authors: Behnke T.
Published: March 2010

A high energy electron positron collider is proposed to complement the large hadron collider, LHC, which has started taking data at CERN, Geneva, Switzerland. Based on superconducting acceleration technology the International Linear Collider ILC is offering a mature proposal. It will deliver high luminosity electron positron collisions at 500 GeV upgradable to 1 TeV. Experimentation at such a collider presents many unique challenges, if the huge physics potential should be harvested efficiently. In this paper after a brief review of the state of the accelerator proposal the state of the preparation of the experimental program is discussed.
Gauge anomaly‐free constraints in neutrino seesaw models
Authors: Emmanuel‐Costa D.
Published: March 2010

The implementation of seesaw mechanisms to give mass to neutrinos in the presence of an anomaly‐free U(1)X gauge symmetry is discussed in the context of minimal extensions of the standard model. It is shown that type‐I and type‐III seesaw mechanisms cannot be simultaneously implemented with an anomaly‐free local U(1)X, unless the symmetry is a replica of the well‐known hypercharge. For combined type‐I/II or type‐III/II seesaw models it is always possible to find nontrivial anomaly‐free charge assignments, which are however tightly constrained, if the new neutral gauge boson is kinematically accessible at LHC. The discovery of the latter and the measurement of its decays into third‐generation quarks, as well as its mixing with the standard Z boson, would allow one to discriminate among different seesaw realisations.
Phenoxodiol inhibits growth of metastatic prostate cancer cells
Authors: Aguero Martin F. , Venero Marina , Brown David M. , Smulson Mark E. , Espinoza Luis A.
Published: March 2010

BACKGROUND

Phenoxodiol, a synthetic analog of Genistein, is being assessed in several clinical studies against a range of cancer types and was shown to have a good efficacy and safety profile. In this study we tested the effects of Phenoxodiol against prostate cancer cell lines.

METHODS

Cell‐cycle analysis, plasmatic membrane damage, clonogenic assay, comet assay, and Western blot methodologies were employed to assess the effects of Phenoxodiol on prostate cancer cell lines. An in vivo model confirmed the potential therapeutic efficacy of Phenoxodiol when administered orally to tumor bearing mice.

RESULTS

Phenoxodiol treatment promoted a marked inhibition of proliferation and loss of colony formation in LNCaP cells in a dose‐ and time‐dependent manner. Similar effects were also observed in the metastatic prostate cell lines PC3 and DU145. Activation of poly(ADP ribose) polymerase 1 (PARP‐1) clearly indicates the induction of DNA damage by Phenoxodiol. Oral administration of Phenoxodiol induced a considerable growth inhibition of malignant tumors generated by inoculation of LNCaP cells into Balb/c nu/nu athymic mice.

CONCLUSIONS

These data demonstrated that Phenoxodiol promotes apoptosis, as determined by PARP‐1 degradation, via mitochondrial depolarization and G1/S cell‐cycle arrest thereby confirming that it is active against androgen‐dependent and independent prostate cancer cells. Although a precise target for Phenoxodiol has not been identified, these data contribute to our understanding of the mechanism by which this drug promotes cell death in prostate cancer cells, and warrants the continued clinical development of Phenoxodiol as a therapeutic for the treatment of metastatic prostate cancer. Prostate 70: 1211–1221, 2010. © 2010 Wiley‐Liss, Inc.
Methoxychalcone induces cell‐cycle arrest and apoptosis in human hormone‐resistant prostate cancer cells through PI 3‐kinase‐independent inhibition of mTOR pathways
Authors: Sun Yu‐Wei , Huang Wei‐Jan , Hsiao Che‐Jen , Chen Yi‐Cheng , Lu Pin‐Hsuan , Guh Jih‐Hwa
Published: March 2010

BACKGROUND

Chalcones are contained in fruits and vegetables, and have been suggested to display anticancer activities. In this study, the anticancer mechanism of WJ9708011 (a methoxychalcone derivative) was delineated in human prostate cancer cells.

METHOD

Cell proliferation was examined by sulforhodamine B and clonogenic assays. Cell‐cycle progression and mitochondrial membrane potential (ΔΨm) were detected by flow cytometric analysis. Expressions of protein and mRNA were detected by Western blot and RT‐PCR technique, respectively. The protein synthesis was examined by [3H]leucine incorporation assay. The overexpression or knockdown techniques for specific target protein were also used in this study.

RESULTS

WJ9708011 induced time‐ and concentration‐dependent G1 arrest of the cell cycle and subsequent apoptosis in human prostate cancer cells. The G1‐arrest effect was confirmed by down‐regulated expressions of several G1‐phase regulators, including cyclin D1, cyclin E, cyclin‐dependent kinase (Cdk)‐4, Cdk2, phospho‐RB, E2F‐1, and Cdc25A. The mRNA expressions of cyclin D1 and cyclin E were also inhibited through the suppression of NF‐κB. WJ9708011 blocked the protein synthesis and inhibited mammalian target of rapamycin (mTOR) signaling pathways. The suppression of mTOR pathways were irrespective of Akt‐ and AMPK‐activated protein kinase (AMPK), but were attributed to mitochondrial stress, in which the down‐regulation of survivin protein level may play a crucial role.

CONCLUSIONS

The data suggest that WJ9708011 induces transcriptional and translational suppression of cell‐cycle regulators that might be through Akt‐ and AMPK‐independent loss of ΔΨm and inhibition of mTOR signaling pathway, leading to G1 arrest of the cell cycle and subsequent apoptotic cell death. Prostate 70:1295–1306, 2010. © 2010 Wiley‐Liss, Inc.
On the contribution of intramolecular kinetics properties of an important rotamer of vinylpyranoanthocyanin‐phenol pigment (portisin)
Authors: Carvalho Alexandre R. F. , Oliveira Joana , de Freitas Victor , Mateus Nuno , Melo André
Published: March 2010

The kinetics of an important rotamerization occurring in vinylpyranoanthocyanin‐phenol pigment (Portisin) was analyzed according to the transition state (TS) formalism. The relevant stationary states, the TS and the equivalent minima, were fully characterized. This included the optimization of the respective geometries and the analytical calculation of all vibrational frequencies. The reaction coordinate was identified, as associated with a single imaginary frequency in TS, and an appropriate intrinsic coordinate analysis (IRC) ensured that this state was connected with the correspondent equivalent minima. For the minimum, the harmonic and one‐dimensional hindered rotor models were used to describe the reaction coordinate. The activation thermodynamics properties were then evaluated. The results obtained were interpreted according to the theoretical models assumed. The results are important for a prompt result for this group of portisins. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Assessing the performances of some recently proposed density functionals for the description of bond dissociations involving organic radicals
Authors: Tognetti Vincent , Cortona Pietro , Adamo Carlo
Published: March 2010

In this article, we have assessed the performances of some recently proposed density functionals for the prediction of reaction energies involving radicals, notably bond dissociations of small organic molecules or of TEMPO‐based ones, and β‐scissions, focusing on our TCA family and on range‐separated hybrids. It is found that no functional belonging to these two families is able to compete with the M0x one. We have tried to improve the performances of the range‐separated hybrids by the optimization of the attenuation parameter, but the improvements for one dataset lead to an unavoidable deterioration for the others. Furthermore, the differences between two different approaches to the long‐range/short‐range separation are discussed in terms of average enhancement factors, emphasizing the crucial choice of the approximate scheme used for the short‐range part. Finally, the influence of the geometries has been considered and found to be negligible for this kind of molecular sets, validating the usual single point energies strategies developed in such benchmarking assessments. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Thermal effects on small para‐hydrogen clusters
Authors: Navarro Jesús , Guardiola Rafael
Published: March 2010

A brief review of different quantum Monte Carlo simulations of small (p‐H2)N clusters is presented. The clusters are viewed as a set of N structureless p‐H2 molecules, interacting via an isotropic pairwise potential. Properties as superfluidity, magic numbers, radial structure, excitation spectra, and abundance production of (p‐H2)N clusters are discussed and, whenever possible, a comparison with 4HeN droplets is presented. All together, the simulations indicate that temperature has a paradoxical effect of the properties of (p‐H2)N clusters, as they are solid‐like at high T and liquid‐like at low T, due to quantum delocalization at the lowest temperature. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
DFT study of vanadyl (IV) complexes with low molecular mass ligands: Picolinate, oxalate, malonate, and maltolate
Authors: Rodrigues Guilherme Dos Santos , da Silva Cunha Ivan , Silva Guilherme Gomes , de Noronha Antonio Luiz Oliveira , de Abreu Heitor Avelino , Duarte Hélio Anderson
Published: March 2010

The insulin‐mimetic activity of the VO2+ complexes are much related to its chemical speciation in the blood serum. Low molecular mass ligands must have an important role in the mechanism of the VO2+ biological activity affecting directly its absorption efficacy. In the present work, the chemical speciation of vanadyl (VO2+) with malonate, maltolate, oxalate and picolinate ligands has been investigated by means of DFT/PCM calculations. Metal/Ligand 1:1 and 1:2 complexes have been calculated. All tautomers, conformations and the presence of water molecules acting as ligand fulfilling the coordination sphere of the metal center have been studied. The results showed that the 1:1 species prefer to have square pyramidal structure with two water molecules in the equatorial axis. The 1:2 species prefer the hexacoordinated structure with one water molecule in the available coordination site in the cis position with respect to the oxo group. The 6‐membered ring malonate complex prefers to keep the square pyramidal structure without water molecule in the coordination sphere. The Gibbs free reaction energy for the formation of the 1:2 complexes from the interaction of the 1:1 complexes and the ligand was estimated. The error of the estimated values compared to the experimental data is not larger than 5 kcal mol−1 at the PBE/TZVP level of theory using the UAHF‐PCM for estimating the solvation free energy. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Domain‐averaged Fermi hole and domain‐restricted reduced density matrices: A critical comparison
Authors: Alcoba Diego R. , Bochicchio Roberto C. , Lain Luis , Torre Alicia
Published: March 2010

The knowledge of the properties and the applicability of domain‐restricted matrices has provided important advances in the description of molecular electronic distributions. In this work, we perform a critical comparison between two different methods: the domain‐averaged Fermi hole (DAFH) approach and the domain‐restricted first‐order reduced density matrix (DRRDM) one, focusing our study on both physical and mathematical points of view. Our results permit to show that both methods have a markedly different behavior at correlated wave function level: the DAFH approach provides information related with electron cloud localization and populations while the DRRDM is a true density matrix. To exemplify the theoretical discussion, we present a numerical test example and a simple analytical model that show such features. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
The CCSD(T) model with Cholesky decomposition of orbital energy denominators
Authors: Cacheiro Javier López , Pedersen Thomas Bondo , Fernández Berta , De Merás Alfredo Sánchez , Koch Henrik
Published: March 2010

A new implementation of the coupled cluster singles and doubles with approximate triples correction method [CCSD(T)] using Cholesky decomposition of the orbital energy denominators is described. The new algorithm reduces the scaling of CCSD(T) from N7 to N6, where N is the number of orbitals. The Cholesky decomposition is carried out using simple analytical expressions that allow us to evaluate a priori the order in which the decomposition should be carried out and to obtain the relevant parts of the vectors whenever needed in the calculation. Several benchmarks have been carried out comparing the performance of the conventional and Cholesky CCSD(T) implementations. The Cholesky implementation shows a speed‐up factor larger than O2/V, where O is the number of occupied and V the number of virtual orbitals, and in general at most 5 vectors are needed to get a precision of μEh. We demonstrate that the Cholesky algorithm is better suited for studying large systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011