bluuebunny/crossref_metadata_2025 huggingface dataset:
A Survey of Routing Protocols in Wireless Body Sensor Networks
Authors: Bangash Javed , Abdullah Abdul , Anisi Mohammad , Khan Abdul
Published: January 2014

Wireless Body Sensor Networks (WBSNs) constitute a subset of Wireless Sensor Networks (WSNs) responsible for monitoring vital sign-related data of patients and accordingly route this data towards a sink. In routing sensed data towards sinks, WBSNs face some of the same routing challenges as general WSNs, but the unique requirements of WBSNs impose some more constraints that need to be addressed by the routing mechanisms. This paper identifies various issues and challenges in pursuit of effective routing in WBSNs. Furthermore, it provides a detailed literature review of the various existing routing protocols used in the WBSN domain by discussing their strengths and weaknesses.
THE INFLUENCE OF THE PRESTRESS OF REINFORCED STEEL ON THE BEHAVIOUR OF THE FLEXURAL ELEMENTS OF REINFORCED CONCRETE / ARMATŪROS IŠANKSTINIŲ ĮTEMPIŲ ĮTAKA GELŽBETONINIŲ LENKIAMŲJŲ ELEMENTŲ ELGSENAI
Authors: Jokūbaitis Aidas
Published: January 2014

This article briefly discusses the essence of prestressed concrete,its advantages and disadvantages. The analysis of prestress lossesis done according to different standards. The paper explainspretensioning force and selection of its eccentricity as well asanalyzes the influence of beam cracking according to limitationson concrete tensile and compressive stresses.

Santrauka

Publikacijoje glaustai aptarta įtemptojo gelžbetonio esmė, pranašumai ir trūkumai. Atlikta nuostolių vertinimo skirtingų normų metodikomis skaičiavimo analizė. Analizuojamas racionalios armatūros įtempimo jėgos ir jos pridėties ekscentriciteto parinkimas. Nagrinėjama leistinųjų betono tempimo ir gniuždymo įtempių įtaka sijų pleišėjimui.
ANALYSIS OF THE PROPERTIES OF HYDROTECHNICAL CONCRETE EMPLOYED IN THE MARINE ENVIRONMENT / JŪRINĖJE APLINKOJE EKSPLOATUOTO HIDROTECHNINIO BETONO SAVYBIŲ ANALIZĖ
Authors: Lebedeva Ramunė
Published: January 2014

Hydrotechnical concrete employed in the marine environmentis strongly influenced by environmental effects such as air temperaturefluctuations, seawater temperature fluctuations, winddirection and speed. All these factors must be analyzed andevaluated designing the composition of hydrotechnical concreteoperating in marine water. The paper is aimed at assessing theproperties of the concrete operated in the marine environment andat analysing the properties of hydrotechnical concrete affectedby seawater with reference to recommendations on designingit. On these grounds, the examination of the impact of sea andriver water has been carried out and the properties of the aboveintroduced two types of water have been compared.

Santrauka

Jūrinėje aplinkoje eksploatuojamam hidrotechniniam betonui didelę įtaką turi aplinkos poveikiai: oro temperatūros svyravimai, jūros vandens temperatūros svyravimai, vėjo kryptis ir greitis. Visi šie veiksniai turi būti ištirti ir vertinami projektuojant hidrotechninių betonų, eksploatuojamų jūros vandenyje, sudėtis. Darbo tikslas – įvertinti jūrinėje aplinkoje eksploatuojamo hidrotechninio betono savybes bei atlikti paveiktų jūros vandens hidrotechninių betonų savybių analizę, pateikiant jų projektavimo rekomendacijas. Atlikta jūros vandens ir Danės upės vandens poveikio hidrotechniniam betonui analizė ir jų savybių palyginimas.
ANALYSIS OF BUILDING INFORMATION MODELLING USING IFC DATA EXCHANGE / PASTATO INFORMACINIO MODELIO DUOMENŲ MAINŲ TAIKANT IFC STANDARTĄ TYRIMAS
Authors: Migilinskas Darius , Galdikas Liudas , Šarka Vaidotas
Published: January 2014

The paper provides an overview of IFC data exchange standardsfor shortcomings and their solution and considers the current situationin Lithuanian construction sector in implementing buildinginformation modelling (BIM) and demand for classification applicationsin construction and design. Also, the article presents theresults of scientific research on the quality of IFC data exchangestandards. Finally, taking into account the made conclusions,recommendations and proposals for the further development ofdigital construction in Lithuania are put forward. Santrauka Straipsnyje apžvelgiami duomenų mainų taikant IFC standartą trūkumai ir jų sprendimas. Pateikiamos Lietuvos statybų sektoriaus tyrimo dėl pastatų informacinio modelio paplitimo, rekomendacijų dėl jo tolesnės plėtros analizė ir išvados. Straipsnyje publikuojami atlikto informacijos mainų taikant IFC standartą kokybės mokslinio tyrimo rezultatai. Atsižvelgiant į visas gautas išvadas, pateikiami rekomendaciniai pasiūlymai tolesnei skaitmeninės statybos plėtrai Lietuvoje ir nustatoma, koks yra naujų tyrimų poreikis.
OPTIMIZATION OF ELASTIC BRIDGE TRUSSES / TAMPRIŲ TILTO SANTVARŲ OPTIMIZAVIMAS
Authors: Rimkus Ignas , Kisevičius Šarūnas , Kalanta Stanislovas
Published: January 2014

The article analyzes the problems of optimizing elastic bridgetrusses, which is a tool for seeking the establishment of theminimum volume (mass) of construction and optimization of thecross-section area and height as well as the structure of the truss.It has been formulated as a nonlinear discrete mathematical programmingproblem. The upper band of the truss works not onlyfor compression but also for bending. The cross-sections of theelements are designed from rolled steel sections. Mathematicalmodels are prepared by using the finite element method and complyingwith requirements for the strength, stiffness and stabilityof the structure. The formulated problems are solved referringto an iterative process and applying the mathematical softwarepackage “MATLAB” along with routine “fmincon”. The ratio ofbuckling is corrected in every case of iteration. Requirementsfor cross-section assortment (discretion) are fulfilled employingthe branch and bound method. Santrauka Darbe nagrinėjami tamprių tilto santvarų optimizavimo uždaviniai, kuriais siekiama nustatyti minimalų konstrukcijos tūrį (masę), optimizuojant strypų skerspjūvius, santvaros aukštį bei tinklelio struktūrą. Jie formuluojami kaip netiesiniai diskrečiojo matematinio programavimo uždaviniai. Santvaros viršutinės juostos elementai ne tik gniuždomieji elementai, bet ir lenkiamieji. Strypų skerspjūviai projektuojami iš plieninių valcuotųjų profiliuočių. Uždavinių matematiniai modeliai sudaromi taikant baigtinių elementų metodą ir atsižvelgiant į konstrukcijos stiprumo, standumo bei pastovumo reikalavimus. Suformuluoti uždaviniai sprendžiamai iteraciniu būdu, naudojant matematinį kompiuterinį paketą MATLAB ir jo paprogramį fmincon. Kiekvienoje iteracijoje koreguojami gniuždomųjų elementų klupumo koeficientai. Skerspjūvių sortimento (diskretiškumo) reikalavimai užtikrinami taikant šakų ir rėžių metodą.
POROSITY PARAMETERS OF CEMENT STONE CONTAINING CHEMICAL ADMIXTURES OF DIFFERENT PURPOSE / CEMENTINIO AKMENS SU SKIRTINGOS PASKIRTIES CHEMINIAIS PRIEDAIS PORINGUMO RODIKLIAI
Authors: Venčkauskas Lukas , Daukšys Mindaugas
Published: January 2014

The conducted research has established a complex influenceand the impact of separate chemical admixtures of differentpurpose on the parameters of the porosity of hardened cementpaste such as open and closed porosity, the average size of poresand the rates of pore inequality. According to the parametersof the porosity of hardened cement paste, on the basis of A. E.Sheikin’s methodology, the number of freezing-thawing cycleswas predicted. This research used plasticizing, viscosity modifyingand antifoaming admixtures. It has been found that, when theamount of plasticizing admixture in cement paste (W/C–0.45) isconstant and makes 1.1% of the cement mass, and the amountof viscosity modifying and antifoaming the admixture increasesfrom 0.1 to 0.6% and from 0.05 to 0.3% respectively, the openporosity of hardened cement paste varies between 30.21% and31.06%, while closed porosity varies between 5.39% and 6.22%.When the amount of the plasticizing admixture in cement paste(W/C–0.45) exceeds 1.1% of the cement mass, the open porosityof hardened cement paste increases by 1.4 times and closedporosity decreases by 2.5 times. While adding 0.1% of the viscositymodifying admixture to cement paste, the open porosityof hardened cement paste is increased by 1.5 times and closedporosity decreases by 2.4 times. The amount of 0.05% of thecement mass of the antifoaming admixture results in the increasedopen porosity of hardened cement paste by 1.5 times and reducedclosed porosity by 3.5 times.

Santrauka

Tyrimo metu nustatyta kompleksinė bei atskirų skirtingos paskirties cheminių priedų įtaka cementinio akmens poringumo rodikliams – atvirajam ir uždarajam poringumui, vidutinio porų dydžio ir porų vienodumo rodikliams. Tyrimuose naudoti cheminiai priedai: plastifikuojantis, klampą modifikuojantis ir mišinyje susiformavusias oro poras suardantis priedas. Nustatyta, kad cemento tešloje (V/C – 0,45) esant pastoviam plastifikuojančio priedo kiekiui – 1,0 % cemento masės, klampą modifikuojančio priedo kiekiui kintant nuo 0,1 iki 0,6 %, o mišinyje susiformavusias oro poras suardančio priedo kiekiui kintant nuo 0,05 iki 0,3 %, cementinio akmens atvirasis poringumas svyruoja nuo 30,21 iki 31,06 %, o uždarasis – nuo 5,39 iki 6,22 %. Cemento tešloje viršijus plastifikuojančio priedo 1,1 % cemento masės, cementinio akmens atvirasis poringumas padidėja apie 1,4 karto, o uždarasis poringumas sumažėja apie 2,5 karto. Pridėjus į tešlą 0,1 % cemento masės klampą modifikuojančio priedo, cementinio akmens atvirasis poringumas padidėja apie 1,5 karto, uždarasis poringumas sumažėja apie 2,4 karto. Oro poras suardančio priedo kiekis 0,05 % cemento masės cementinio akmens atvirąjį poringumą padidina apie 1,5 karto, uždarąjį poringumą sumažina apie 3,5 karto.
ANALYSIS OF THE EFFECTIVENESS OF POLYPROPYLENE FIBERS USAGE AS SORBENTS OF OIL SPILLS RESULTING FROM THE TRANSPORT ACCIDE / POLIPROPILENO PLUOŠTO NAUDOJIMO EFEKTYVUMAS IŠSILIEJUS NAFTAI TRANSPORTO OBJEKTUOSE
Authors: Sęk Jerzy , Shtyka Olga , Szymczak Kamila
Published: January 2014

The effectiveness of polypropylene fibers as sorbents of oil-water emulsions was the object of the research in the present publication. Thus the sorption capacity of the synthetic material of the regional production with for emulsions of different concentration was investigated.

Santrauka

Straipsnyje nagrinėjama polipropileno pluošto naudojimo avarinionaftos išsiliejimo metu problema. Polipropileno pluoštasnaudojamas kaip naftą sugerianti medžiaga. Pateiktos skirtingostorio polipropileno pluošto išsiliejusios naftos sugeriamumosavybės.
RESEARCH INTO THE INFLUENCE OF TURBOCHARGER SYSTEM LEAKAGE ON THE PARAMETERS OF THE EXTERNAL WORK OF 1.9 TDI DIESEL ENGINE / TURBOKOMPRESORINĖS ORO PRIPŪTIMO SISTEMOS NESANDARUMO ĮTAKOS 1.9 TDI DYZELINIO VARIKLIO IŠORINIAMS DARBO PARAMETRAMS TYRIMAI
Authors: Žaglinskis Justas , Vėgneris Ričardas , Rimkus Alfredas , Rapalis Paulius , Melaika Mindaugas
Published: January 2014

The article presents and analyses the comparable results of thestand tests of 1.9 TDI diesel engine. The purpose of the conductedresearch included solving a question of how losses in thecharge-air system impacted environmental and energy-economicalparameters in order to ensure the same load characteristicsof the diesel engine. The leakage factor was imitated by a holeof 3.1 mm in diameter, the size of which is possible in practice.Therefore, some significant negative changes were observed. Inall tested range of the loaded engine, a decrease of 6.7...7.8 %in charge pressure impacts an increase in greenhouse gas emissionsby 11...30 %. Fuel consumption increased by 11...14 %and difference in the deterioration of other indicators sometimesvaried compared with normal operating conditions. It was alsofound that, in a case of leakage, the electronic engine control unitinefficiently reduced the emission of the products of incompletecombustion in exhaust gases.

Santrauka

Straipsnyje pateikti dyzelinio variklio Audi 1.9 TDI palyginamieji stendinių tyrimų rezultatai bei jų analizė. Tyrimo tikslas buvo suformuotas autoriams iškėlus klausimą, kaip pripūtimo sistemos nesandarumas daro įtaką dyzelinio variklio ekonominiams-energetiniams ir ekologiniams rodikliams siekiant užtikrinti tas pačias apkrovos charakteristikas. Nesandarumo faktorių imituojant 3.1 mm skersmens anga, kurios dydis praktikoje realiai tikėtinas, buvo pastebėti reikšmingi neigiami pokyčiai. Kritus pripūtimo slėgiui 6,7–7,8 % šiltnamio dujų emisija tiriamajame variklio apkrovos diapazone išaugo 11–30 %, degalų sunaudojimas išaugo 11–14 %, kitų rodiklių pablogėjimas lyginant su įprastos eksploatacijos sąlygomis skyrėsi kartais. Nustatyta, jog esant nesandarumui variklio elektroninė valdymo sistema neefektyviai mažina nevisiško degimo produktų emisiją.
ANALYSIS OF VEHICLE LATERAL STABILITY ESTIMATING SUSPENSION CHARACTERISTICS ON THE SNOWY AND DRY ROAD / AUTOMOBILIO SKERSINIO STOVUMO ANALIZĖ VERTINANT PAKABOS CHARAKTERISTIKAS VAŽIUOJANT SNIEGUOTA IR SAUSA KELIO DANGA
Authors: Žuraulis Vidas , Kemzūraitė Kristina , Levulytė Loreta
Published: January 2014

This paper analyzes the lateral dynamics of the vehicle withindependent suspension. The tests have been made driving inan incremental acceleration mode under conditions of a circulartrajectory within 10, 15 and 20-meter radius. The literature reviewprovides a summary of recent research re-lated to the topics discussedin this article. The article looks at the interaction of thesnowy and dry road with wheels and its influence on the lateraloscillation of a vehicle. The displacement of different sides ofvehicle suspension and its variation in acting lateral accelerationhave also been estimated. Data on the performed tests of theconducted research have been graphically plotted thus presentingthe summarized results and conclusions. Santrauka Straipsnyje analizuojama automobilio su nepriklausoma pakaba skersinė dinamika. Tyrimai atlikti važiuojant didėjančiu greičiu 10, 15 ir 20 m spindulio apskritimine trajektorija. Literatūros apžvalgoje pateikiama su straipsnio tematika susijusių naujausių tyrimų apžvalga. Analizuojama sausos bei snieguotos kelio dangos sąveika su ratais ir įtaka automobilio šoniniam svirimui. Įvertinama skirtingų automobilio pusių pakabos eigos ir jų kitimas veikiant skersiniam pagreičiui. Atliktų tyrimų duomenys vaizduojami grafiškai, rezultatai apibendrinami ir pateikiamos išvados.
INVESTIGATION INTO THE MODEL OF THE VEHICLE SYSTEM FOR SPEED SUPPORT / AUTOMOBILIO GREIČIO PALAIKYMO SISTEMOS MODELIO TYRIMAS
Authors: Grigorovič Jurij , Junevičius Raimundas
Published: January 2014

The paper presents a rectilinear motion of a car modelled applyingsoftware package “Matlab/Simulink“ where two vehicles aremoving simultaneously one after the other. The parameters ofeach vehicle have been identified separately assessing a driver,road and environment. Santrauka Šiame straipsnyje pateikiamas programiniu paketu ,,Matlab/Simulink“ sumodeliuotas tiesiaeigis automobilio judėjimas, kai modeliuojami du, vienas paskui kitą važiuojantys automobiliai, kiekvieno automobilio parametrai, kai vertinamas vairuotojas, kelio danga, aplinka, pasirenkami atskirai.
Copper-based alloy artefacts from the Témiscamingue fur trade post (Quebec, Canada)
Authors: Moreau Jean-François , Hancock Ron G.V. , Côté Marc
Published: January 2014

One hundred and forty-four artefacts from the collection of copper-based alloy specimens excavated from the site of Fort Témiscamingue (Western Quebec, Canada; late 16th to 18th centuries) were submitted to instrumental neutron activation analysis. While some specimens were brassy copper (high copper and very low zinc content), others were brass (lower copper and high zinc content). The brass artefacts confirm the indication based on historical documents of the settling of Fort Témiscamingue in the 1720 since metal Zn began to be produced in Europe by the beginning of the 18th century. The brassy copper artefacts could be containers made with 17th century techniques but still in use when Fort Témiscamingue was erected, or they could indicate direct or indirect trade with the French during the 17th century.
Improvement of diabetic patients nursing care by the development of educational programs
Authors: Vissarion Bakalis , Malliarou Maria , Theofilou Paraskevi , Zyga Sofia
Published: January 2014

Diabetes is a major health problem with many social and economic consequences in general population. The importance of education in the diabetic patient and his family, led to the development of diabetes clinical nurse specialist. The role of diabetes clinical nurse specialist is essential and crucial to the hospitals and the community, in order to form a relationship with the diabetic patient and his/her family. In this way health is promoted to the maximum extent possible. In conclusion educational programs help patients with diabetes to obtain information about their condition and improve their self-care skills
Anaesthetic considerations for evoked potentials monitoring
Authors: Bithal Parmod
Published: January 2014

Intra-operative neurophysiologic monitoring (IONM) under anaesthesia has achieved popularity because it helps prevent/ minimize neurologic morbidity from surgical manipulations of various neurologic structures. Neurologic functions in an anaesthetised patient can be monitored either by electroencephalography (EEG) or by evoked potentials. Whereas, EEG is difficult to analyse, evoked potentials, in contrast, are easy to interpret, they are either present or absent, delayed or not delayed, with normal or abnormal wave. The goal of IONM is to identify changes in nervous system function prior to irreversible damage. Many factors need consideration when selecting an anaesthetic regimen for intra-operative monitoring of evoked potentials. The very pathophysiological condition or the potential risks of the contemplated surgical procedure, which require evoked potentials monitoring, may place constraints on anaesthetic management as well. With the availability of numerous anaesthetic techniques, an appropriate plan for managing both anaesthesia and IONM in a patient should be organised. It is extremely essential not to alter the pharmacological state of the patient to avoid any changes in the recording of evoked responses. While an anaesthesiologist may alter plans for a patient in order to facilitate IONM, monitoring team too, sometimes may be required to modify plans for monitoring when a particular anaesthetic agent or technique is strongly indicated or contraindicated. At times, compromise may be required between an anaesthesia technique and a monitoring technique. To serve patients’ best interest, it is critical to have a team approach and good communication among the neurophysiologist, anaesthesiologist and surgeon.
Coagulation effects of mannitol in combination with 0.9% normal saline or hydroxyethyl starch in patients undergoing supratentorial craniotomy: A preliminary report
Authors: Prabhakar Hemanshu , Singh Gyaninder , Bithal Parmod , Kalaivani Mani
Published: January 2014

Background: Neurosurgical patients often require administration of both, mannitol and hydroxyethyl starch (HES). A recent in vitro study demonstrated that HES in combination with mannitol could disturb coagulation parameters and should be avoided in neurosurgical practice. The aim of our study was to evaluate coagulation abnormalities due to mannitol when administered alone and in combination with HES in patients undergoing craniotomy for various intracranial brain tumours. Materials and Methods: We enrolled 30 adult patients undergoing craniotomy. Patients were randomised into two groups using a computer generated randomisation chart. Interventions: Group A: Patients received 10 ml/kg 0.9% normal saline and 1 g/kg mannitol and Group B: Patients received 10 ml/kg, HES 130/0.4, and 1 gm/kg mannitol; immediately after induction of general anaesthesia. Rotational thromboelastography was done immediately after induction of general anaesthesia and 5 min after administration of mannitol. Measured parameters of blood coagulation were clotting time (CT) and clot formation time (CFT) with EXTEM and maximum clot firmness (MCF) with EXTEM and (FIBTEM). Results: Fourteen patients in each group completed the study. Insignificant change was noted in CT; CFT altered significantly from the baseline in both the groups (P < 0.05). MCF with FIBTEM did not change significantly from baseline (P > 0.05), but significantly differed between groups (P = 0.001). However, all values were in normal range. Conclusion: Mannitol 1 g/kg and HES 10 ml/kg can be safely administered in patients undergoing craniotomy for supratentorial tumours, without clinically significant changes in coagulation parameters.
Dans les « coulisses » du métier d’opérateur de vidéosurveillance
Authors: Le Goff1 Tanguy
Published: January 2014

Pièces maîtresses des dispositifs de vidéosurveillance mis en place dans nombre de villes françaises aujourd’hui, les opérateurs officiant derrière les écrans demeurent pourtant des acteurs de la sécurité dont on sait peu de chose. Rares sont en effet les travaux de recherche, aussi bien en France que dans les pays anglo-saxons, qui se sont intéressés à ce nouveau métier de surveillance à distance. Nous souhaitons, dans cet article, donner à voir en quoi il consiste en s’appuyant sur une enquête réalisée auprès d’opérateurs de deux salles de vidéosurveillance de communes françaises. Par cette perspective d’analyse, notre étude s’inscrit dans la lignée des recherches de type ethnographique visant à observer les pratiques professionnelles quotidiennes des principaux utilisateurs d’une technologie pour appréhender ce qui se joue dans le circuit de production de la sécurité.
Spider Silk Coatings as a Bioshield to Reduce Periprosthetic Fibrous Capsule Formation
Authors: Zeplin Philip H. , Maksimovikj Nathalie C. , Jordan Martin C. , Nickel Joachim , Lang Gregor , Leimer Axel H. , Römer Lin , Scheibel Thomas
Published: January 2014

Medical grade silicones have been employed for decades in medical applications. The associated long‐term complications, such as capsule formation and contraction have, however, not been fully addressed yet. The aim of this study is to elucidate if capsule formation and/or contraction can be mitigated by veiling the surface of the silicone during the critical phase after implantation. Medical grade silicone implants are homogeneously coated with a micrometer thin layer of recombinant spider silk proteins. Biocompatibility analysis in vitro and in vivo focuses on specific physiological reactions. Applying quantitative methods for the determination of marker‐specific gene expression and protein concentration, it is detected that the silk coating inhibits fibroblast proliferation, collagen I synthesis, and differentiation of monocytes into CD68‐positive histiocytes. It significantly reduces capsule thickness, post‐operative inflammation, synthesis and re‐modeling of extracellular matrix, and expression of contracture‐mediating factors. Therefore, coatings made of recombinant spider silk proteins considerably reduce major post‐operative complications associated with implantation of silicone‐based alloprosthetics, such as capsular fibrosis and contraction, rendering spider silk coatings a bioshield for such implants.
Controlled Generation of Microspheres Incorporating Extracellular Matrix Fibrils for Three‐Dimensional Cell Culture
Authors: Workman Victoria L. , Tezera Liku B. , Elkington Paul T. , Jayasinghe Suwan N.
Published: January 2014

A growing body of evidence suggests that studying cell biology in classical two‐dimensional formats, such as cell culture plasticware, results in misleading, non‐physiological findings. This paper describes the optimization of a microsphere‐based system permitting 3D cell culture incorporating physiological extracellular matrix components. Bio‐electrospraying, the most advanced method currently available, is used to produce microspheres containing THP‐1 cells as a model cell line. The bio‐electrospraying para­meters of nozzle size, polymer flow rate, and voltage are systematically investigated in order to allow stable production of size‐controlled microspheres containing extracellular matrix material and human cells. The effect of bio‐electrospraying parameters, alginate type and cell concentration on cell viability are investigated using trypan blue and propidium iodide staining. Bio‐electrospraying has no effect on cell viability nor the ability of cells to proliferate. Cell viability is similarly minimally affected by encapsulation in all types of alginate tested (MVM, MVG, chemical and food‐grade). Cell density of 5 × 106 cells mL−1 within microspheres is the optimum for cell survival and proliferation. The stable generation of microspheres incorporating cells and extracellular matrix for use in a 3D cell culture will benefit study of many diverse diseases and permit investigation of cellular biology within a 3D matrix.
Heat Induced Passivation of CuInSe2 Surfaces: A Strategy to Optimize the Efficiency of Chalcopyrite Thin Film Solar Cells?
Authors: Mönig Harry , Lockhorn David , Aghdassi Nabi , Timmer Alexander , Kaufmann Christian A. , Caballero Raquel , Zacharias Helmut , Fuchs Harald
Published: January 2014

Despite the success of chalcopyrite thin film solar cells, many open questions are related to the complex defect physics at the interface between the n‐type window layer and the p‐type chalcopyrite absorber, which largely determines the device efficiency. Therefore, this study aims to clarify the defect physics of chalcopyrite thin film surfaces, which is investigated by scanning tunneling spectroscopy, photoelectron, and inverse photoelectron spectroscopy. After removing surface oxides by a wet chemical KCN treatment and subsequent annealing at 280 °C in ultrahigh vacuum, a complete passivation of defect levels is observed, which goes along with a type inversion and an enlarged band gap at the surface. Therefore, this sample state consolidates three exclusively beneficial properties, which potentially minimize interface recombination losses and increase the open circuit voltage in completed devices. In contrast, oxidation of the surface by annealing in air reduces the surface band bending and creates a high density of charge compensated defect levels, implying exclusively detrimental effects on the device performance due to the presence of oxygen at the window/absorber heterojunction. These results are discussed in view of previous models suggesting a passivation of defect levels upon oxygenation of the interface.
α‐Diazo β‐Keto Ester as Precursor to Aromatic CH Insertion and Wolff Rearrangement with Different Directing Groups
Authors: Ma Biao , Chen Fang‐Lei , Xu Xing‐Yu , Zhang Yi‐Nan , Hu Li‐Hong
Published: January 2014

A tunable aromatic CH insertion and a Wolff rearrangement of α‐diazo β‐keto esters precursor were developed. Different directing groups on nitrogen led with high selectivity to either dihydroquinoline or 2‐carbamoylacrylate motifs, which can be transformed to multiple heterocyclic scaffolds.

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Zinc‐Catalyzed Direct Cyanation of Indoles and Pyrroles: Nitromethane as a Source of a Cyano Group
Authors: Nagase Yuta , Sugiyama Tetsuya , Nomiyama Shota , Yonekura Kyohei , Tsuchimoto Teruhisa
Published: January 2014

With nitromethane and diphenylsilane (Ph2SiH2), zinc triflate behaves as a Lewis acid catalyst for the cyanation of nitrogen‐containing heteroarenes such as indoles and pyrroles. This is the first realization of the Lewis acid‐catalyzed direct cyanation of a C(aryl)H bond with no CN group‐containing cyanating agent.

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Palladium‐Catalyzed Decarbonylative Dehydration of Fatty Acids for the Production of Linear Alpha Olefins
Authors: Liu Yiyang , Kim Kelly E. , Herbert Myles B. , Fedorov Alexey , Grubbs Robert H. , Stoltz Brian M.
Published: January 2014

A highly efficient palladium‐catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even‐numbered natural fatty acids into valuable and expensive odd‐numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent‐free and relatively mild conditions.

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Surface Modification of Castor Oil‐Based Polyurethane by Polyacrylic Acid Graft using a Two‐Step Plasma Treatment for Biomedical Applications
Authors: Najafabadi Seyed Ahmad Ayati , Keshvari Hamid , Sarkhosh Hadi , Ashuri Maziar , Tahriri Mohammadreza
Published: January 2014

The aim of this study is design and prepare medical grade polyurethane (PU) film based on castor oil without any additives. Acrylic acid (AAc) was grafted onto the surface of PU films using a two‐step oxygen plasma treatment. The first step of this method includes oxygen plasma pretreatment of the PU films, immersion in AAc monomeric solution, removal from the solution, and drying. The second step was carried out by plasma polymerization of preadsorbed reactive monomers on the surfaces of dried pretreated films. The effects of pretreatment time length and monomer concentration were studied on AAc graft amount. The surface of the modified PU films were characterized using attenuated total reflection Fourier transform infrared (ATR‐FTIR) spectroscopy, scanning electron microscopy (SEM), and water drop contact angle measurements. The ATR‐FTIR results proved that the carbonyl (CO) and hydroxyl groups (OH) of AAc give rise to an absorption peak at 1698 cm–1, which was observed in the spectra of the modified PU. The SEM micrographs showed that poly(acrylic Acid) (PAAc)–grafted PU films have a different pattern compared with nonmodified PU films. Moreover, it was found that a decrease in contact angle indicated to a higher grafting amount of polymer. Finally, L929 fibroblast cell culture was done onto the PAAc–PU films. It was observed that cells are spherical and not uniformly distributed on the modified polymer surface.
Effect of Novolac Resin and Modified Novolac Resin on Mechanical Properties of Carbon Fiber/Epoxy Composites
Authors: He Hongwei , Gao Feng , Li Kaixi , Yan Shen
Published: January 2014

The effects of novolac resin (NR) and modified novolac resin (MNR) on the stiffness and toughness of the carbon fiber (CF)/epoxy composites were studied when using these two kinds of modifiers with different physical and chemical performance. The results show that both NR and MNR are excellent toughening agents for the CF/epoxy composites, and the composites treated with MNR present better toughness than that of NR. However, the stiffness of the composites is almost unchanged when adding MNR. The mechanisms were analyzed by fracture studies using scanning electron microscopy and the decrease of cross‐link density caused by MNR was deduced to the toughening effects.
Palladium‐Catalyzed Odorless One‐Pot Synthesis of Vinyl Sulfides from Organohalides, Thiourea, and Alkynes
Authors: Feng Jie , Lu Guoping , Lv Meifang , Cai Chun
Published: January 2014

The preparation of vinyl sulfides via a three‐component reaction of organohalides, thiourea, and alkynes was reported. Two carbon‐sulfur bonds are formed in one pot in this palladium‐catalyzed system. The protocol is free of foul‐smelling thiols and is operated under mild conditions to obtain cis‐configured anti‐Markovnikov products with moderate to excellent yields and excellent selectivity. In addition, this method is noteworthy given its experimental simplicity, high generality, good functional group tolerance, and the low cost of the catalyst system.
PTG protein depletion rescues malin‐deficient Lafora disease in mouse
Authors: Turnbull Julie , Epp Jonathan R. , Goldsmith Danielle , Zhao Xiaochu , Pencea Nela , Wang Peixiang , Frankland Paul W. , Ackerley Cameron A. , Minassian Berge A.
Published: January 2014

Ubiquitin ligases regulate quantities and activities of target proteins, often pleiotropically. The malin ubiquitin E3 ligase is reported to regulate autophagy, the misfolded protein response, microRNA silencing, Wnt signaling, neuronatin‐mediated endoplasmic reticulum stress, and the laforin glycogen phosphatase. Malin deficiency causes Lafora disease, pathologically characterized by neurodegeneration and accumulations of malformed glycogen (Lafora bodies). We show that reducing glycogen production in malin‐deficient mice by genetically removing PTG, a glycogen synthesis activator protein, nearly completely eliminates Lafora bodies and rescues the neurodegeneration, myoclonus, seizure susceptibility, and behavioral abnormality. Glycogen synthesis downregulation is a potential therapy for the fatal adolescence onset epilepsy Lafora disease. Ann Neurol 2014;75:442–446
Selective Catalytic Transfer Dehydrogenation of Alkanes and Heterocycles by an Iridium Pincer Complex
Authors: Yao Wubing , Zhang Yuxuan , Jia Xiangqing , Huang Zheng
Published: January 2014

Catalytic alkane dehydrogenation is a reaction with tremendous potential for application. We describe a highly active PSCOP‐pincer iridium catalyst for transfer dehydrogenation of cyclic and linear alkanes. The dehydrogenation of linear alkanes occurs under relatively mild conditions with high regioselectivity for α‐olefin formation. In addition, the catalyst system is very effective in the dehydrogenation of heterocycles to form heteroarenes and olefinic products.
Metal‐Free Deoxygenation of Carbohydrates
Authors: Adduci Laura L. , McLaughlin Matthew P. , Bender Trandon A. , Becker Jennifer J. , Gagné Michel R.
Published: January 2014

The conversion of readily available cellulosic biomass to valuable feedstocks and fuels is an attrative goal but a challenging transformation that requires the cleavage of multiple nonactivated CO bonds. Herein, the Lewis acid trispentafluorophenylborane (B(C6F5)3) is shown to catalyze the metal‐free hydrosilylative reduction of monosaccharides and polysaccharides to give hydrocarbons with reduced oxygen content. The choice of the silane reductant influences the degree of deoxygenation, with diethylsilane effecting the complete reduction to produce hexanes while tertiary silanes give partially deoxygenated tetraol and triol products.
A Luminescent Dye@MOF Platform: Emission Fingerprint Relationships of Volatile Organic Molecules
Authors: Dong Ming‐Jie , Zhao Min , Ou Sha , Zou Chao , Wu Chuan‐De
Published: January 2014

Self‐assembly of luminescent moieties into porous metal–organic frameworks (MOFs) has generated many luminescent platforms for probing volatile organic molecules (VOMs). However, most of those explored thus far have only been based on the luminescence intensity of one transition, which is not efficient for probing different VOMs. We have synthesized a luminescent MOF material containing 1D nanotube channels, and further developed a luminescent dye@MOF platform to realize the probing of different VOMs by tuning the energy transfer efficiency between two different emissions. The dye@MOF platform exhibits excellent fingerprint correlation between the VOM and the emission peak‐height ratio of ligand to dye moieties. The dye@MOF sensor is self‐calibrating, stable, and instantaneous, thus the approach should be a very promising strategy to develop luminescent materials with unprecedented practical applications.
Zink‐katalysierte Borylierung von primären, sekundären und tertiären Alkylhalogeniden mit Alkoxydiborreagentien bei Raumtemperatur
Authors: Bose Shubhankar Kumar , Fucke Katharina , Liu Lei , Steel Patrick G. , Marder Todd B.
Published: January 2014

Als neuartiges Beispiel eines Gruppe‐XII‐Katalysators zur C‐X‐Borylierung wurde ein katalytisches System basierend auf einer ZnII‐NHC‐Vorstufe für die Kreuzkupplung von Alkylhalogeniden mit Diborreagentien entwickelt. Durch diesen Ansatz wurde die Borylierung von nicht‐aktivierten primären, sekundären und tertiären Alkylhalogeniden zu Alkylboronaten bei Raumtemperatur erreicht. Die Umsetzungen erfolgen unter milden Bedingungen bei guter Toleranz anderer funktioneller Gruppen. Erste Ergebnisse bezüglich des Reaktionsmechanismus der Borylierungsreaktion deuten auf die Beteiligung von Ein‐Elektronen‐Prozessen hin.
CH–π and CF–π Interactions Lead to Structural Changes of N‐Heterocyclic Carbene Palladium Complexes
Authors: Xu Xiangya , Pooi Benjamin , Hirao Hajime , Hong Soon Hyeok
Published: January 2014

The role of CH–π and CF–π interactions in determining the structure of N‐heterocyclic carbene (NHC) palladium complexes were studied using 1H NMR spectroscopy, X‐ray crystallography, and DFT calculations. The CH–π interactions led to the formation of the cis‐anti isomers in 1‐aryl‐3‐isopropylimidazol‐2‐ylidene‐based [(NHC)2PdX2] complexes, while CF–π interactions led to the exclusive formation of the cis‐syn isomer of diiodobis(3‐isopropyl‐1‐pentafluorophenylimidazol‐2‐ylidene) palladium(II).
Patternable Large‐Scale Molybdenium Disulfide Atomic Layers Grown by Gold‐Assisted Chemical Vapor Deposition
Authors: Song Intek , Park Chibeom , Hong Misun , Baik Jaeyoon , Shin Hyun‐Joon , Choi Hee Cheul
Published: January 2014

A novel way to grow MoS2 on a large scale with uniformity and in desired patterns is developed. We use Au film as a catalyst on which [Mo(CO)6] vapor decomposes to form a Mo‐Au surface alloy that is an ideal Mo reservoir for the growth of atomic layers of MoS2. Upon exposure to H2S, this surface alloy transforms into a few layers of MoS2, which can be isolated and transferred on an arbitrary substrate. By simply patterning Au catalyst film by conventional lithographic techniques, MoS2 atomic layers in desired patterns can be fabricated.
Protein products obtained by site‐preferred partial crosslinking in protein crystals and “liberated” by redissolution
Authors: Buch Michal , Wine Yariv , Dror Yael , Rosenheck Sonia , Lebendiker Mario , Giordano Rita , Leal Ricardo M.F. , Popov Alexander N. , Freeman Amihay , Frolow Felix
Published: January 2014

The use of protein crystals as a source of nanoscale biotemplates has attracted growing interest in recent years owing to their inherent internal order. As these crystals are vulnerable to environmental changes, potential applications require their stabilization by chemical crosslinking. We have previously shown that such intermolecular chemical crosslinking reactions occurring within protein crystals are not random events, but start at preferred crosslinking sites imposed by the alignment of protein molecules and their packing within the crystalline lattice. Here we propose a new working hypothesis and demonstrate its feasibility in enabling us to extricate homogeneous populations of single protein molecules that display chemical point mutations or of dimers that show homogeneous chemical crosslinking, and that have the potential for isolation of higher structures. Characterization of the crosslinking mechanism and its end products opens the way to the potential retrieval of such specific modified/intermolecular crosslinked products simply by effecting partial crosslinking at identified preferred sites, followed by time‐controlled arrest of the crosslinking reaction and dissolution of the crystals by medium exchange complemented by chromatographic purification. Biotechnol. Bioeng. 2014;111: 1296–1303. © 2014 Wiley Periodicals, Inc.
Simultaneous stereoselective analysis of naftopidil and O‐desmethyl naftopidil enantiomers in rat feces using an online column‐switching high‐performance liquid chromatography method
Authors: Zhang Yun‐Ying , Liu Xia‐Wen , Zhu Li‐Jun , Yuan Mu
Published: January 2014

A novel online column‐switching chiral high‐performance liquid chromatography method was developed and validated for the simultaneous determination of naftopidil (NAF) and its O‐desmethyl metabolites (DMN) enantiomers in rat feces. Direct and multiple injections of supernatant from rat feces homogenate were allowed through the column‐switching system. Analyte extraction was performed on the Capcell Pak mixed‐functional column by acetonitrile–phosphate buffer (pH 7.4; 10 mm; 8:92, v/v) flowing at 1 mL/min. Separation of NAF and DMN enantiomers was achieved on the Chiralpak IA column by methanol–acetonitrile–acetate buffer (pH 5.3; 5 mm; 45:33:22, v/v/v) flowing at 0.5 mL/min. The analytes were measured with a fluorescence detector at 290 nm (λex) and 340 nm (λem). The validated method showed a good linearity [22.5–15,000 ng/mL for (+)‐/(−)‐NAF; 35–25,000 ng/mL for (+)‐/(−)‐DMN] and the lowest limits of quantification for NAF and DMN enantiomers were 22.5 and 35 ng/mL, respectively. Both intra‐ and inter‐day variations were <10%. The assay was successfully applied to the fecal excretion of NAF and DMN enantiomers in rat after single oral administration of (±)‐NAF. Nonstereoselective excretion of (+)‐ and (−)‐NAF was found in feces, while stereoselective excretion of (+)‐ and (−)‐DMN was observed with higher excretion levels of (+)‐DMN, indicating that there may exist stereoselective metabolism for NAF enantiomers. Copyright © 2014 John Wiley & Sons, Ltd.
Development of a method for the determination of cefovecin in plasma by HPLC
Authors: Cox Sherry , Martin Ali , Hamill Mallery , Pistole Nealy , Steeil James , Schumacher Juergen
Published: January 2014

A simple high‐performance liquid chromatography method for the determination of cefovecin in small volume plasma has been developed. Following solid‐phase extraction using Oasis HLB cartridges, samples were separated by reverse‐phase high‐performance liquid chromatography on an XBridge C8 (3.5 µm) 4.6 × 250 mm column and quantified using ultraviolet detection at 280 nm. The mobile phase was a mixture of 10 mm ammonium acetate (pH 3.5) and acetonitrile (89:11), with a flow rate of 0.85 mL/min. The standard curve ranged from 0.1 to 200 µg/mL. Intra‐ and Inter‐assay variability for cefovecin was <10%, and the average recovery was >90%. The lower limit of quantitation was 0.1 µg/mL. This method was successfully applied to the analysis of cefovecin samples at our institution. This is also the first fully validated method with an internal standard that does not use mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.
Neural substrates of socioemotional self‐awareness in neurodegenerative disease
Authors: Sollberger Marc , Rosen Howard J. , Shany‐Ur Tal , Ullah Jerin , Stanley Christine M. , Laluz Victor , Weiner Michael W. , Wilson Stephen M. , Miller Bruce L. , Rankin Katherine P.
Published: January 2014

Background

Neuroimaging studies examining neural substrates of impaired self‐awareness in patients with neurodegenerative diseases have shown divergent results depending on the modality (cognitive, emotional, behavioral) of awareness. Evidence is accumulating to suggest that self‐awareness arises from a combination of modality‐specific and large‐scale supramodal neural networks.

Methods

We investigated the structural substrates of patients' tendency to overestimate or underestimate their own capacity to demonstrate empathic concern for others. Subjects' level of empathic concern was measured using the Interpersonal Reactivity Index, and subject‐informant discrepancy scores were used to predict regional atrophy pattern, using voxel‐based morphometry analysis. Of the 102 subjects, 83 were patients with neurodegenerative diseases such as behavioral variant frontotemporal dementia (bvFTD) or semantic variant primary progressive aphasia (svPPA); the other 19 were healthy older adults.

Results

bvFTD and svPPA patients typically overestimated their level of empathic concern compared to controls, and overestimating one's empathic concern predicted damage to predominantly right‐hemispheric anterior infero‐lateral temporal regions, whereas underestimating one's empathic concern showed no neuroanatomical basis.

Conclusions

These findings suggest that overestimation and underestimation of one's capacity for empathic concern cannot be interpreted as varying degrees of the same phenomenon, but may arise from different pathophysiological processes. Damage to anterior infero‐lateral temporal regions has been associated with semantic self‐knowledge, emotion processing, and social perspective taking; neuropsychological functions partly associated with empathic concern itself. These findings support the hypothesis that—at least in the socioemotional domain—neural substrates of self‐awareness are partly modality‐specific.
Methylmercury toxicity: amelioration by selenium and water‐soluble chelators as N‐acetyl cysteine and dithiothreitol
Authors: Joshi Deepmala , Mittal Deepak Kumar , Shukla Sangeeta , Srivastav Ajai Kumar , Srivastav Sunil Kumar
Published: January 2014

The protective potential of chelators, i.e. N‐acetyl cysteine (0.6 mg /kg, intraperitoneally) and dithiothreitol (15.4 mg kg−1, intraperitoneally) with selenium (0.5 mg kg−1, pre‐oral) were evaluated individually and in combination against methylmercury‐induced biochemical alterations and oxidative stress consequences. Forty‐two male Sprague–Dawley rats were exposed with methylmercury (1.5 mg kg−1, pre‐oral) daily for 21 days followed by different treatments for five consecutive days. Administration of methylmercury caused significant enhancement in the release of transaminases, alkaline phosphatases and lactate dehydrogenases in serum. A significant increased was observed in lipid peroxidation level with a concomitant decreased in glutathione content after methylmercury exposure in liver, kidney and brain. Hepatic microsomal drug metabolizing enzymes (aniline hydroxylase and amidopyrine N‐demethylase) of cytochrome p4502E1 showed sharp depletion after methylmercury exposure. Alterations in histological changes in liver, kidney and brain were also noted in methylmercury administered group. All treated groups showed recovery pattern, but the combined treatments with N‐acetyl cysteine and dithiothreitol in combination with selenium were more effective than that with either alone treatments in recovering blood biochemical changes after methylmercury toxicity. In conclusion, the results demonstrated that combination therapy may recover all blood biochemical alterations and offer maximum protection against methylmercury‐induced toxicity. Copyright © 2014 John Wiley & Sons, Ltd.
Acetylcholine Promotes Binding of α‐Conotoxin MII at α3β2 Nicotinic Acetylcholine Receptors
Authors: Sambasivarao Somisetti V. , Roberts Jessica , Bharadwaj Vivek S. , Slingsby Jason G. , Rohleder Conrad , Mallory Chris , Groome James R. , McDougal Owen M. , Maupin C. Mark
Published: January 2014

α‐Conotoxin MII (α‐CTxMII) is a 16‐residue peptide with the sequence GCCSNPVCHLEHSNLC, containing Cys2–Cys8 and Cys3–Cys16 disulfide bonds. This peptide, isolated from the venom of the marine cone snail Conus magus, is a potent and selective antagonist of neuronal nicotinic acetylcholine receptors (nAChRs). To evaluate the impact of channel–ligand interactions on ligand‐binding affinity, homology models of the heteropentameric α3β2‐nAChR were constructed. The models were created in MODELLER with the aid of experimentally characterized structures of the Torpedo marmorata‐nAChR (Tm‐nAChR, PDB ID: 2BG9) and the Aplysia californica‐acetylcholine binding protein (Ac‐AChBP, PDB ID: 2BR8) as templates for the α3‐ and β2‐subunit isoforms derived from rat neuronal nAChR primary amino acid sequences. Molecular docking calculations were performed with AutoDock to evaluate interactions of the heteropentameric nAChR homology models with the ligands acetylcholine (ACh) and α‐CTxMII. The nAChR homology models described here bind ACh with binding energies commensurate with those of previously reported systems, and identify critical interactions that facilitate both ACh and α‐CTxMII ligand binding. The docking calculations revealed an increased binding affinity of the α3β2‐nAChR for α‐CTxMII with ACh bound to the receptor, and this was confirmed through two‐electrode voltage clamp experiments on oocytes from Xenopus laevis. These findings provide insights into the inhibition and mechanism of electrostatically driven antagonist properties of the α‐CTxMIIs on nAChRs.