bluuebunny/crossref_metadata_2025_split huggingface dataset:
High efficiency photovoltaic module based on mesoscopic organometal halide perovskite
Authors: Matteocci Fabio , Cinà Lucio , Di Giacomo Francesco , Razza Stefano , Palma Alessandro L. , Guidobaldi Andrea , D'Epifanio Alessandra , Licoccia Silvia , Brown Thomas M. , Reale Andrea , Di Carlo Aldo 
Published: November 2014

AbstractWe fabricated monolithic solid state modules based on organometal CH3NH3PbI3 and CH3NH3PbI3 − xClx perovskites using poly‐(3‐hexylthiophene) and Spiro‐OMeTAD as hole transport materials (HTMs). In particular, we developed innovative and scalable patterning procedures to minimize the series resistance at the integrated series‐interconnections. By using these optimization steps, we reached a maximum conversion efficiency of 8.2% under AM1.5G at 1 Sun illumination conditions using the CH3NH3PbI3 − xClx perovskite and the poly‐(3‐hexylthiophene) as HTM. Finally, we investigated the double‐step deposition of CH3NH3PbI3 using the Spiro‐OMeTAD, reaching a maximum conversion efficiency on active area (10.08 cm2) equal to 13.0% (9.1% on aperture area) under AM1.5G at 1 Sun illumination conditions. This remarkable result represents the highest PCE value reached for the perovskite solar modules. Copyright © 2014 John Wiley & Sons, Ltd.
Kinetics of the inhibition of styrene polymerization by nitro compounds
Authors: Tüdös F. , Kende I. , Azori M. 
Published: November 2014

AbstractA kinetic study has been made of the inhibiting action of s‐trinitrobenzene and its derivatives on the initiation of styrene polymerization. The effect of −CH3, −OH, −OCH3, −NH2, −Cl, −CO2C2H5 as substituents was investigated. The nitro compounds were found to be weak inhibitors of styrene polymerization. They bring about a well defined inhibition period during which the reaction mixture usually darkens. During the inhibition phase the rate of polymerization gradually increases, but the rate of polymerization afterwards is lower than during the noninhibited process. It concerns the fact that the initial inhibitor transforms to a retarder about 20 times weaker. In the light of this the basic equations of inhibition followed by retardation have been derived. Such are, for example, equations for the polymerization rate, for the kinetics of inhibitor consumption, and also a formula for determining the duration of the inhibition phase on the basis of dilatometric data. Procedures have also been developed for determining the inhibition and retardation constants and the stoichiometric coefficient indicating number of radicals deactivated by one molecule of inhibitor. The inhibition constants (as well as retardation constants) have been shown to obey the Hammett rule in the case of substituents of small volume (−H, −CH3, −OCH3, −Cl). The inhibition reactivity of the compounds is the higher, the higher the electron acceptor properties of the substituent. In the case of the −CO2C2H5 group the activity is below that expected from the Hammett rule, which is evidently the result of a decrease in conjugation. In the case of OH and NH2 substituents the activity is much above that given by the rule, because the hydrogen bond has an additional electron acceptor effect on the nitro group.
Investigation of the reaction of organomagnesium compounds with the salts of heavy metals, and the use of organomagnesium compounds and their complexes for polymerization
Authors: Erusalimskiǐ B. L. , Fo‐Sung Wang , Kavunenko A. P. 
Published: November 2014

AbstractThe behavior of some systems of the type MgRX−MenXn in the presence of free radical acceptors has been studied with the purpose of throwing some light on the nature of the reaction magnified image.It is shown that such agents affect neither the yield nor the ratio of hydrocarbons noted above. This indicates the absence of free radical stages in this reaction. Data have been obtained on the polymerization of some olefins and dienes in the presence of the systems [G4H9MgI + (C4H9)2Mg]−TiXn. The organomagnesium compounds have been found capable of initiating the polymerization of isoprene in the absence of titanium salts. The polyisoprene produced in this case contains 96–99% of 3,4‐unite.
Study of degradation of polyphosphates in aqueous solution
Authors: Thilo E. , Wieker W. 
Published: November 2014

AbstractCyclic trimetaphosphate is formed along with monophosphate and some di‐ and triphosphate on the degradation of chainlike polyphosphates in aqueous solution at pH 8 and 60°C. This degradation is catalytically accelerated by many metal salts. The kinetic examination of the degradation reaction in the presence of some selected metal salts shows that its catalytic effect is closely connected with the ion exchange capacity of the polyphosphates. The higher the affinity of a metal cation to the polyphosphate, i.e., the stronger it is bound, the higher is its catalytic activity. This increases in the order K < Na < Li < Ba < Sr < Ca < Mg < Al. From the kinetics of the degradation reaction it follows, contrary to our previous investigations, that degradation does not occur only from the chain end but statistically over the whole polymer molecule and that the formation of trimetaphosphate is not connected with the formation of the monophosphate. A new scheme of reaction for the formation of the cyclic trimetaphosphate from the chainlike polyphosphates is developed. According to this the primary step of the degradation consists of an intramolecular “phosphorylation” of the polyphosphate, which is then followed by hydrolysis of the trimetaphosphate.
Mechanism of protective action of benzene rings in radiolysis of polystyrene
Authors: Pravednikov A. N. , Shen‐Kan In 
Published: November 2014

AbstractThe crosslinking energy in the radiolysis of polystyrene is 100‐fold that of polyethylene, whereas the free radical yield in the radiation of linear paraffins is only 5–6 times as much as that from alkylaromatic compounds. Therefore, the high radiation stability of polystyrene cannot be explained by the conventional scheme for the action of the benzene rings. In order to explain the high radiation stability of polystyrene the mechanism of the reactions taking place during radiolysis of the polymer must be examined. A hydrogen atom liberated as the result of rupture of a C–H bond under the action of radiation may react in two ways: (1) abstraction of a hydrogen atom from the aliphatic chain, and (2) addition to the double bond of the benzene ring with the formation of a free radical of the cyclohexadienyl type. Owing to the low rate of diffusion in the solid polymers and the high rate of reaction with atomic hydrogen, the radicals formed in this way should be in the immediate vicinity of the primary radical. Interaction of the latter with the radical formed by removal of a hydrogen atom from the aliphatic chain will lead to the formation of crosslinks. The interaction between the primary radical and the radical of the cyclohexadienyl type may take place in the following two ways. The radicals may recombine with each other to form crosslinks or they may engage in a disproportionation reaction. Disproportionation will lead to restoration of the initial state and hence to the dissipation of energy without crosslink formation. This will result in a drop in efficiency of the crosslinking process, the energy for the formation of one crosslink increasing. In order to obtain experimental verification of the above conceptions as to the mechanism of interaction of the primary and cyclohexadienyl radicals, the radiolysis of deuterated toluene C4H5CD3 was studied at the temperature of liquid nitrogen. The addition to the benzene ring of a deuterium atom formed on rupture of a C–D bond under the action of radiation and the subsequent disproportionation of the cyclohexadienyl and primary radicals should, owing to the isotope effect, lead to transition of deuterium atoms from the aliphatic chain to the ring. The results obtained showed that the rate of these processes should exceed by at least 5–6 fold the rate of the processes leading to crosslinkage. It thus follows that the high radiation stability of polystyrene is to a considerable extent associated with disproportionation of the primary and cyclohexadienyl radicals.
Oxidative transformations in cellulose molecules
Authors: Ivanov V. I. , Lenshina N. Ya. , Ivanova V. S. 
Published: November 2014

AbstractIt is shown that in all cellulose specimens isolated from plant tissues there are non‐hydroxyl groups in the 1‐, 2‐, 3‐, and 6‐positions of some of the glucose repeating unite. The presence of trace amounts of these groups changes the physical and chemical properties of the cellulose. For the purpose of studying the effect of the functional groups on the stability of the glucoside bond in the cellulose molecule and also to obtain oxidized products of importance by themselves, we have investigated the possible paths of cellulose oxidation. As an extension of previous work devoted to the primary oxidative reactions of cellulose we have studied oxidation by sodium periodate with subsequent oxidation by nitrogen oxides. This procedure yielded products containing 220 COOH groups per 100 glucose residues. These groups are in the 2‐, 3‐, and 6‐positions. The reactions showed that in opened pyran rings there is hindrance to the oxidation of primary OH groups. In contrast to other methods, which give products with not more than 50% of the theoretical number of dicarboxyl groups, the successive oxidation of cellulose by sodium periodiate yielded theoretical amounts of dicarboxycellulose with respect to carboxyl group content. The oxidation products obtained have a fibrous structure, dissolve in dilute aqueous sodium hydroxide, are relatively resistant to acid hydrolysis, are stable in air, and contain only traces of nitrogen, in contrast to dicarboxy‐ and monocarboxycelluloses. This type of oxidized cellulose, which we have termed tricarboxycellulose, possesses high and selective ion exchange properties, allowing cations, among them proteins, to be separated. This new type of oxidized fibrous cellulose permits a new direction to be developed in paper chromatography.
Synthesis of new derivatives of cellulose and other polysaccharides
Authors: Rogovin Z. A. , Derevitskaya V. A. , Tun Sun' , Weǐ‐Gan Chzhan , Gal'Braikh L. S. 
Published: November 2014

AbstractA method has been developed for the synthesis of esters of cellulose and ω‐amino acids and a preliminary study has been made of their properties. Experiments have been made on their modification through the reactive amino groups. The esters of ω‐chlorovaleric and ω‐chloroenanthic acids as well as the mixed esters of acetic and chlorovaleric acids were synthesized and the properties of this new type of cellulose esters have been investigated. Various monocarboxylcellulose amides have been synthesized. The hydrazides of the carboxylated polysaccharides were prepared, and a number of reactions were carried out with the objective of further modifying the properties of these polysaccharides. Cellulose‐polyamide graft copolymers with the polyamide molecule in the side chain were prepared. The synthesis of the graft copolymers of dicarboxycellulose and polyamides of which each elementary unit of the main chain contained two side chains of low molecular polyamides were carried out.
“Weak links” in polysaccharide chains as related to modified groups
Authors: Rånby Bengt G. 
Published: November 2014

AbstractCelluloses of different origin are hydrolyzed at different rates in acid medium both in fiber form (heterogeneous process) and in solution (homogeneous process). On the basis of measurements for well purified samples of commercial wood and cotton celluloses, molecularly dissolved in concentrated phosphoric acid, it was recently proposed that the fact that initial rates of hydrolysis are higher for wood cellulose than for cotton cellulose is largely related to inductive effects from modified (electrophilic) groups, e.g., carboxyls and carbonyls. Some of these groups are no doubt introduced during purification processes involving oxidative bleaching. It is possible that some of the modified groups are of native origin, but they are few (less than one modified group for 400 glucose units). The probable mechanisms for the influence on the rate of hydrolysis of modified groups, e.g., inductive and steric effects, rearrangements of the ring structure, are discussed in relation to the present knowledge of polysaccharide reactions. The concepts of inductive effects are supported by evidence from the hydrolysis of hemicelluloses and other polysaccharides containing uronic acid groups.
Initiating directed synthesis of modified celluloses by nitrogen oxides
Authors: Ermolenko I. N. , Kaputsky F. N. 
Published: November 2014

AbstractIn connection with a scheme, previously suggested by the author, for the mechanism of oxidation of cellulose by nitrogen oxides which explains the selectivity of the process, experiments were conducted which confirm that the role of N2O3 constitutes interaction with cellulose macroradicals generated in the previous reaction with NO2(N2O4). Addition of nitrogen oxides under the action of phosphoric acid solutions to cellulose leads to an increase in the content of bound phosphorus in the products, determined as the function which is present in the form of molecular compounds, including H3PO4, cellulose, and possibly HNO3.
Radiation copolymerization of acrylonitrile with polystyrene and perchlorovinyl
Authors: Usmanov Kh. U. , Musaev U. N. , Tillaev R. S. 
Published: November 2014

AbstractWith the objective of obtaining polymers with new, valuable properties in recent years considerable importance has been attached to the synthesis of graft and block copolymers. Such copolymers combine the properties of their polymeric constituents. In order to form graft and block copolymers it is necessary that the starting material possess active centers, which may be groups capable of forming free radicals. To carry out a graft or block copolymerization various chemical and physical methods yielding polymeric free radicals are employed. One of the new methods of synthesizing graft and block polymers is the radiation method. In the present work the results of experiments on the formation of graft polystyrene and perchlorovinyl polymers with acrylonitrile by the action of gamma rays are presented. Co™ served as radiation source. The reaction was carried out by subjecting a swollen polystyrene film in acrylonitrile to doses of 1 × 106−4 × 106 r. The resultant product was separated from the homo‐polymer by extraction. As the results obtained have shown, the percentage of grafting over the range studied increases with increasing radiation dose. The monomer unit to polymer ratio has been calculated from data on the nitrogen content. Also a graft polymer of perchlorovinyl and acrylonitrile was obtained by preliminary irradiation of perchlorovinyl in the presence of air. The thermomechanical properties of the resultant polymers were investigated. The results showed that graft polymers of polystyrene and perchlorovinyl possess greater thermal stability than the initial polymers. In the study the radiation polymerization of acrylonitrile was also carried out and the viscosity of polyacrylonitrile solutions was measured.
Autotaxin-LPA Axis Regulates hMSC Migration by Adherent Junction Disruption and Cytoskeletal Rearrangement Via LPAR1/3-Dependent PKC/GSK3β/β-Catenin and PKC/Rho GTPase Pathways
Authors: Ryu Jung Min , Han Ho Jae 
Published: November 2014

AbstractBioactive molecules and stem cell-based regenerative engineering is emerging a promising approach for regenerating tissues. Autotaxin (ATX) is a key enzyme that regulates lysophosphatidic acid (LPA) levels in biological fluids, which exerts a wide range of cellular functions. However, the biological role of ATX in human umbilical cord blood-derived mesenchymal stem cells (hMSCs) migration remains to be fully elucidated. In this study, we observed that hMSCs, which were stimulated with LPA, accelerated wound healing, and LPA increased the migration of hMSCs into a wound site in a mouse skin wound healing model. In an experiment to investigate the effect of LPA on hMSC migration, ATX and LPA increased hMSC migration in a dose-dependent manner, and LPA receptor 1/3 siRNA transfections inhibited the ATX-induced cell migration. Furthermore, LPA increased Ca2+ influx and PKC phosphorylation, which were blocked by Gαi and Gαq knockdown as well as by Ptx pretreatment. LPA increased GSK3β phosphorylation and β-catenin activation. LPA induced the cytosol to nuclear translocation of β-catenin, which was inhibited by PKC inhibitors. LPA stimulated the binding of β-catenin on the E-box located in the promoter of the CDH-1 gene and decreased CDH-1 promoter activity. In addition, the ATX and LPA-induced increase in hMSC migration was blocked by β-catenin siRNA transfection. LPA-induced PKC phosphorylation is also involved in Rac1 and CDC42 activation, and Rac1 and CDC42 knockdown abolished LPA-induced F-actin reorganization. In conclusion, ATX/LPA stimulates the migration of hMSCs through LPAR1/3-dependent E-cadherin reduction and cytoskeletal rearrangement via PKC/GSK3β/β-catenin and PKC/Rho GTPase pathways. Stem Cells 2015;33:819–832
Induced Pluripotent Stem Cells Restore Function in a Human Cell Loss Model of Open-Angle Glaucoma
Authors: Abu-Hassan Diala W. , Li Xinbo , Ryan Eileen I. , Acott Ted S. , Kelley Mary J. 
Published: November 2014

Abstract
Normally, trabecular meshwork (TM) and Schlemm's canal inner wall endothelial cells within the aqueous humor outflow pathway maintain intraocular pressure within a narrow safe range. Elevation in intraocular pressure, because of the loss of homeostatic regulation by these outflow pathway cells, is the primary risk factor for vision loss due to glaucomatous optic neuropathy. A notable feature associated with glaucoma is outflow pathway cell loss. Using controlled cell loss in ex vivo perfused human outflow pathway organ culture, we developed compelling experimental evidence that this level of cell loss compromises intraocular pressure homeostatic function. This function was restored by repopulation of the model with fresh TM cells. We then differentiated induced pluripotent stem cells (iPSCs) and used them to repopulate this cell depletion model. These differentiated cells (TM-like iPSCs) became similar to TM cells in both morphology and expression patterns. When transplanted, they were able to fully restore intraocular pressure homeostatic function. This successful transplantation of TM-like iPSCs establishes the conceptual feasibility of using autologous stem cells to restore intraocular pressure regulatory function in open-angle glaucoma patients, providing a novel alternative treatment option. Stem Cells 2015;33:751–761
Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem Cells
Authors: Kranc Kamil R. , Oliveira Daniel V. , Armesilla-Diaz Alejandro , Pacheco-Leyva Ivette , Catarina Matias Ana , Luisa Escapa Ana , Subramani Chithra , Wheadon Helen , Trindade Marlene , Nichols Jennifer , Kaji Keisuke , Enver Tariq , Bragança José 
Published: November 2014

Abstract
Identifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells. Stem Cells 2015;33:699–712
Novel non‐coherent and half‐coherent receivers for amplify‐and‐forward relaying
Authors: Khan Fahd Ahmed , Chen Yunfei , Alouini Mohamed‐Slim 
Published: November 2014

AbstractConsider a system in which the signal is transmitted from the source to the destination via a relay. The source–relay link and the relay–destination link are assumed to have Rician fading. For such a system, in this paper, we propose a novel non‐coherent receiver that detects the signal without knowledge of channel state information (CSI). In addition, we also propose novel receivers for the situation when only partial CSI is available at the destination; that is, channel knowledge of either the source–relay link or the relay–destination link, but not both, is available. These receivers are termed as “half‐coherent receivers” because they have the CSI of only one of the two links in the system. These half‐coherent receivers can be used in applications in which only the relay can afford additional complexity (e.g., the relay may be a base station) and includes a channel estimation module to acquire channel knowledge of the source–relay link or only the destination includes the channel estimation module to acquire channel knowledge of the relay–destination link. The symbol error rate performances of the proposed receivers for M‐ary frequency‐shift keying are derived for Rician fading. Numerical results show that considerable performance gains can be achieved by using these new receivers, especially at a low signal‐to‐noise ratio where the gain is needed most. Copyright © 2014 John Wiley & Sons, Ltd.
Botulinum Toxin A Injection to Facial and Cervical Paraspinal Muscles in a Patient With Stiff Person Syndrome: A Case Report
Authors: Pakeerappa Praveen N. , Birthi Pravardhan , Salles Sara 
Published: November 2014

AbstractStiff person syndrome (SPS) is a rare neurologic disorder of unknown etiology characterized by increased resting muscle tone, progressive rigidity, and stiffness of the axial musculature. We present a case of a 48‐year‐old male patient with SPS who experienced facial and neck muscle spasms that were uncontrolled with oral medications and the use of an intrathecal baclofen pump. Botulinum toxin A injections into the bilateral masseter and neck paraspinal muscles provided pain relief and spasm control, illustrating the use of botulinum toxin A injections in the small muscles of face and neck in patients with SPS.
Comparison of the Thickness of Lateral Abdominal Muscles Between Pregnant Women With and Without Low Back Pain
Authors: Rostami Mohsen , Noormohammadpour Pardis , Mansournia Mohammad Ali , Hantoushzadeh Sedigheh , Farahbakhsh Farzin , Nourian Ruhollah , Kordi Ramin 
Published: November 2014

AbstractObjectivesTo compare the thickness of the external oblique, internal oblique, and transversus abdominis muscles in pregnant subjects with and without low back pain (LBP) by the use of ultrasound to measure thickness.DesignA case‐control study.SettingAn academic and tertiary care referral spine and sports medicine center.ParticipantsFifty pregnant women with LBP during pregnancy and 54 pregnant control subjects.MethodsCase and control subjects were matched for body mass index, gestational age, and number of previous pregnancies. A multiple linear regression model with adjustment for the gestational age of the subjects, as the potential confounder of the primary outcomes, was used to evaluate the association between LBP appearance and abdominal muscles thickness of the subjects.Main Outcome MeasuresThe thickness of lateral abdominal muscles was measured by ultrasound with the subject in a hook‐lying position on the examination table.ResultsWe found that there was no significant difference between pregnant subjects with and without LBP in terms of the thickness of external oblique, internal oblique, and transversus abdominis muscles.ConclusionThese findings suggest that other factors rather than the thickness of core stabilizing muscles are influential in the etiology of LBP during pregnancy. We hypothesize that enlargement of uterus during pregnancy might influence the thickness of the lateral abdominal muscles.