bluuebunny/crossref_metadata_2025 huggingface dataset:
From Geomodels to Engineering Models—Opportunities for Spreadsheet Computing
Authors: Bhattacharya Saibal , Watney W. Lynn , Doveton John H. , Guy Willard J. , Bohling Geoff
Published: April 2012

Data used to build reservoir models come from different scales, such as core, log, well tests, pressure and production profiles, and seismic; thus they carry the inherent need for calibration to a common scale. Unfortunately, as no accepted procedure is available to solve this calibration problem, doubts remain about the representativeness of the data that are often used to describe a reservoir model. In the absence of a standardized upscaling method, a series of procedural steps, described in this paper, can be employed on data gathered from different sources to test and build a coherent reservoir model. Each step in this procedure is a part of an iteration loop that checks for consistency and coherency among the available data. In case of a mismatch, the process encourages the user to go back to the previous step or steps and revise one or more of the relevant assumptions. The method outlined in this paper, the Super Pickett crossplot, integrates data from different sources such as cores, well logs, and well performance to build a volumetric geomodel that is then used to validate the mass balance calculation. The strength of this method lies in the fact that the major elements (the Super Pickett plot, the volumetric and material balance calculations) of the process can be performed in a spreadsheet environment, making it both cost effective, versatile, and portable. This exercise enables the building of an internally consistent geo-engineering model representing the reservoir. Such a model can be used effectively as the basis for reservoir simulation studies.
Assessing the risk of infectious Cryptosporidium in drinking water
Authors: Rochelle Paul A. , Johnson Anne M. , De Leon Ricardo , Di Giovanni George D.
Published: April 2012

Treated drinking water from 14 surface water treatment plants serving a combined population of approximately 9 million people was monitored for infectious Cryptosporidium oocysts using immunofluorescence microscopy to detect infections in cell culture. No infectious oocysts were detected in 370 samples with a total filtered volume of 349,053 L. The calculated risk of waterborne Cryptosporidium infection for the communities served by the 14 sampled plants was < 1 in 10,000. However, more accurate risk assessments of the threat to public health posed by Cryptosporidium in drinking water are still needed. This study demonstrated that routine infectivity monitoring of large volumes of treated drinking water is feasible. Consequently, testing finished water for infectious Cryptosporidium should be considered during periods of regulatory monitoring such as the second round of the Long Term 2 Enhanced Surface Water Treatment Rule.
Controlling copper corrosion in new construction by organic matter removal
Authors: Arnold Roger B. , Griffin Allian , Edwards Marc
Published: April 2012

A new elementary school with persistent elevated copper corrosion by‐product release evaluated pH increase, orthophosphate dosing, and granular activated carbon (GAC) treatment as potential corrosion control measures using bench‐scale experiments. Removal of natural organic matter (NOM) with temporary GAC treatment facilitated the formation of a copper scale with a permanently diminished (> 85%) solubility via an accelerated natural scale‐aging process. Increasing the pH and adding a high dose of orthophosphate were also effective for decreasing copper release but presented significant long‐term drawbacks, and their benefits were reversed if the treatments were discontinued. Temporary GAC treatment may be a holistically attractive option to reduce copper corrosion problems in new construction in certain waters with high levels of NOM.
The Analytics Society of Ireland
Authors: Brugha Cathal M.
Published: April 2012

In this article, we chronicle the history of the Analytics Society of Ireland (An Cumann Eireannach d'Anailísí), which was founded in 1964 as the Operations Research Society of Ireland (ORSI). We discuss the changes the society has undergone, the meetings and activities in which the society has engaged, and the publications the society has produced. We also provide information about some of the key individuals who have been instrumental in the establishment and development of the society.
Estonian Operational Research Society
Authors: Vaarmann Otu
Published: April 2012

The Estonian operational research society (EstORS) is a sovereign voluntary nonprofit organization located in Estonia, Tallinn (
http://www.ioc.ee/matem/estors/
). EstORS will be ruled and regulated by its statutes in accordance with the Constitution of the Estonian Republic as well as pertinent Estonian Laws and Regulations. The society unites experts in the field of operational research/industrial mathematics and its applications, actively working for the development of Estonian Republic as an information society. According to its statutory mission, EstORS aims at contributing to the progress of scientific and technical knowledge, integrating competence of engineering science and management science/operations research, creating and transferring scientific knowledge in informatics and decisions systems. The paper concerns the birth of EstORS and its goals and activities. The main purpose of the EstORS is to promote the establishment of international contacts and stimulate further advancement of academic links and free exchange of experience between its members and members of other similar scientific societies belonging to this country, this region and the world.
Exercise training in juvenile dermatomyositis
Authors: Omori Clarissa Harumi , Silva Clovis Artur Almeida , Sallum Adriana Maluf Elias , Rodrigues Pereira Rosa Maria , Lúciade Sá Pinto Ana , Roschel Hamilton , Gualano Bruno
Published: April 2012

Objective

To investigate the effects of a supervised exercise training program on health parameters, physical capacity, and health‐related quality of life in patients with mild and chronic juvenile dermatomyositis (DM).

Methods

This was a prospective longitudinal study following 10 children with mild and chronic juvenile DM (disease duration >1 year). The exercise program consisted of twice‐a‐week aerobic and resistance training. At baseline and after the 12‐week intervention, we assessed muscle strength and function, aerobic conditioning, body composition, juvenile DM scores, and health‐related quality of life.

Results

Child self‐report and parent proxy‐report Pediatric Quality of Life Inventory scores were improved after the intervention (−40.3%; P = 0.001 and −48.2%; P = 0.049, respectively). Importantly, after exercise, the Disease Activity Score was reduced (−26.9%; P = 0.026) and the Childhood Muscle Assessment Scale was improved (+2.5%; P = 0.009), whereas the Manual Muscle Test presented a trend toward statistical significance (+2.2%; P = 0.081). The peak oxygen consumption and time‐to‐exhaustion were increased by 13.3% (P = 0.001) and 18.2% (P = 0.003), respectively, whereas resting heart rate was decreased by 14.7% (P = 0.006), indicating important cardiovascular adaptations to the exercise program. Upper and lower extremity muscle strength and muscle function were also significantly improved after the exercise training (P < 0.05). Both the whole‐body and the lumbar spine bone mineral apparent density were significantly increased after training (1.44%; P = 0.044 and 2.85%; P = 0.008, respectively).

Conclusion

We showed for the first time that a 12‐week supervised exercise program is safe and can improve muscle strength and function, aerobic conditioning, bone mass, disease activity, and health‐related quality of life in patients with active and nonactive mild and chronic juvenile DM with near normal physical function and quality of life.
Do patients with non‐radiographic axial spondylarthritis differ from patients with ankylosing spondylitis?
Authors: Kiltz Uta , Baraliakos Xenofon , Karakostas Pantelis , Igelmann Manfred , Kalthoff Ludwig , Klink Claudia , Krause Dietmar , Schmitz‐Bortz Elmar , Flörecke Martina , Bollow Matthias , Braun Jürgen
Published: April 2012

Objective

Patients with axial spondylarthritis (SpA) who have structural changes in the sacroiliac joints and/or the spine have been classified as having ankylosing spondylitis (AS), while those without such changes are now classified as having nonradiographic axial SpA (nr‐axSpA). The differentiating features are incompletely understood.

Methods

Data from 100 consecutive patients with axial SpA not treated with tumor necrosis factor antagonists were compared clinically and with laboratory parameters, spinal radiographs, and magnetic resonance imaging (MRI) of the spine. Standardized clinical assessment tools were used to assess health status.

Results

AS was diagnosed in 56 patients and nr‐axSpA in 44 patients. Signs of inflammation were significantly higher in patients with AS than in patients with nr‐axSpA, with a median C‐reactive protein level of 8.0 versus 3.8 mg/liter, a median Ankylosing Spondylitis Disease Activity Score of 2.2 versus 2.8, respectively, and a median amount of spinal inflammatory lesions on MRI of 2.0 versus 0.0, respectively. Significant differences between these 2 groups were seen in sex (76.8% male AS patients versus 31.8% male nr‐axSpA patients). Clinical variables did not differ between patients with AS and nr‐axSpA (Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, Ankylosing Spondylitis Quality of Life questionnaire, Short Form 36 health survey).

Conclusion

Patients with nr‐axSpA were characterized by the low proportion of male patients and the low burden of inflammation compared to patients with AS. While both groups did not differ regarding health status, disease activity, and physical function, they did differ in signs of inflammation; all were higher in patients with AS. Since many patients with nr‐axSpA had not developed structural changes after years of symptoms, we propose that those patients should not be regarded as having preradiographic AS but rather as having nr‐axSpA.
Body weight changes and corresponding changes in pain and function in persons with symptomatic knee osteoarthritis: A cohort study
Authors: Riddle Daniel L. , Stratford Paul W.
Published: April 2012

Objective

To determine if a dose‐response relationship exists between percentage changes in body weight in persons with symptomatic knee osteoarthritis (OA) and self‐reported pain and function.

Methods

Data from persons in the Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis (MOST) study data sets (n = 1,410) with symptomatic function‐limiting knee OA were studied. For the OAI, we used baseline and 3‐year followup data, while for the MOST study, baseline and 30‐month data were used. Key outcome variables were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function and pain change scores. In addition to covariates, the predictor variable of interest was the extent of weight change over the study period divided into 5 categories representing different percentages of body weight change.

Results

A significant dose‐response relationship (P < 0.003) was found between the extent of percentage change in body weight and the extent of change in WOMAC physical function and WOMAC pain scores. For example, persons who gained ≥10% of body weight had WOMAC physical function score changes of −5.4 (95% confidence interval −8.7, −2.00) points, indicating worsening physical function relative to the reference group of persons with weight changes between <5% weight gain and <5% weight reduction.

Conclusion

Our data suggest a dose‐response relationship exists between changes in body weight and corresponding changes in pain and function. The threshold for this response gradient appears to be body weight shifts of ≥10%. Weight changes of ≥10% have the potential to lead to important changes in pain and function for patient groups as well as individual patients.
Parents' preferences for drug treatments in juvenile idiopathic arthritis: A discrete choice experiment
Authors: Burnett Heather F. , Regier Dean A. , Feldman Brian M. , Miller Fiona A. , Ungar Wendy J.
Published: April 2012

Objective

To examine parents' preferences for drug treatments and health outcomes in juvenile idiopathic arthritis (JIA) and identify demographic and health‐related factors that significantly impact choice.

Methods

A discrete choice experiment was conducted with 105 parents of children with JIA who were cared for by a rheumatologist at The Hospital for Sick Children in Canada. Attributes evaluated included “drug treatment,” “child reported pain from arthritis,” “participation in daily activities,” “side effects,” “days missed from school,” and “cost to you.” Multinomial logit regression was used to estimate the relative importance of each attribute level and interaction term.

Results

Parents made tradeoffs between characteristics of the drug treatments and health outcomes. “Participation in daily activities” was the most important attribute, followed by “child reported pain from arthritis” and “cost to you.” Parents of children with longer disease durations had stronger preferences for improved participation in daily activities, whereas parents of older JIA patients had stronger preferences for improved control of pain.

Conclusion

Parents of children with JIA demonstrated strong preferences for treatments that reduce pain and improve daily functioning regardless of the associated side effects, level of responsibility required for drug administration, and days missed from school. Parents of children with longer disease durations and those who had been prescribed aggressive therapies had a greater preference for treatment effectiveness. These findings support the need for considering parental preferences in decisions regarding the choice of treatment for JIA.
A Highly Efficient, Blue‐Phosphorescent Device Based on a Wide‐Bandgap Host/FIrpic: Rational Design of the Carbazole and Phosphine Oxide Moieties on Tetraphenylsilane
Authors: Liu He , Cheng Gang , Hu Dehua , Shen Fangzhong , Lv Ying , Sun Guannan , Yang Bing , Lu Ping , Ma Yuguang
Published: April 2012

A new series of wide‐bandgap materials, 4‐dipenylphosphine oxide‐4′‐9H‐carbazol‐9‐yl‐tetraphenylsilane (CSPO), 4‐diphenylphosphine oxide‐4′,4″‐di(9H‐carbazol‐9‐yl)‐tetraphenylsilane (pDCSPO), 4‐diphenylphosphine oxide ‐4′‐[3‐(9H‐carbazol‐9‐yl)‐carbazole‐9‐yl]‐tetraphenylsilane (DCSPO), 4‐diphenylphosphine oxide‐4′,4″,4″′‐tri(9H‐carbazol‐9‐yl)‐tetraphenylsilane (pTCSPO) and 4‐diphenylphosphine oxide ‐4′‐[3,6‐di(9H‐carbazol‐9‐yl)‐9H‐carbazol‐9‐yl]‐tetraphenylsilane (TCSPO), containing different ratios and linking fashions of p‐type carbazole units and n‐type phosphine oxide units, are designed and obtained. DCSPO is the best host in FIrpic‐doped devices for this series of compounds. By utilizing DCzSi and DPOSi as hole‐ and electron‐transporting layers, a high EQE of 27.5% and a maximum current efficiency of 49.4 cd A−1 are achieved in the DCSPO/FIrpic doped device. Even at 10 000 cd m−2, the efficiencies still remain 41.2 cd A−1 and 23.0%, respectively.
Up‐Conversion Luminescent and Porous NaYF4:Yb3+, Er3+@SiO2 Nanocomposite Fibers for Anti‐Cancer Drug Delivery and Cell Imaging
Authors: Hou Zhiyao , Li Chunxia , Ma Ping'an , Cheng Ziyong , Li Xuejiao , Zhang Xiao , Dai Yunlu , Yang Dongmei , Lian Hongzhou , Lin Jun
Published: April 2012

Up‐conversion (UC) luminescent and porous NaYF4:Yb3+, Er3+@SiO2 nanocomposite fibers are prepared by electrospinning process. The biocompatibility test on L929 fibrolast cells reveals low cytotoxicity of the fibers. The obtained fibers can be used as anti‐cancer drug delivery host carriers for investigation of the drug storage/release properties. Doxorubicin hydrochloride (DOX), a typical anticancer drug, is introduced into NaYF4:Yb3+, Er3+@SiO2 nanocomposite fibers (denoted as DOX‐NaYF4:Yb3+, Er3+@SiO2). The release properties of the drug carrier system are examined and the in vitro cytotoxicity and cell uptake behavior of these NaYF4:Yb3+, Er3+@SiO2 for HeLa cells are evaluated. The release of DOX from NaYF4:Yb3+, Er3+@SiO2 exhibits sustained, pH‐sensitive release patterns and the DOX‐NaYF4:Yb3+, Er3+@SiO2 show similar cytotoxicity as the free DOX on HeLa cells. Confocal microscopy observations show that the composites can be effectively taken up by HeLa cells. Furthermore, the fibers show near‐infrared UC luminescence and are successfully applied in bioimaging of HeLa cells. The results indicate the promise of using NaYF4:Yb3+, Er3+@SiO2 nanocomposite fibers as multi‐functional drug carriers for drug delivery and cell imaging.
Synthesis of Ceria–Zirconia Nanocrystals with Improved Microstructural Homogeneity and Oxygen Storage Capacity by Hydrolytic Sol–Gel Process in Coordinating Environment
Authors: Epifani Mauro , Andreu Teresa , Abdollahzadeh‐Ghom Sara , Arbiol Jordi , Morante Joan R.
Published: April 2012

Ceria–zirconia solid solution nanocrystals, (1‐x)CeO2–xZrO2, 0 ≤ x ≤ 1, are prepared by sol–gel processing in dodecylamine of solutions obtained by forced hydrolysis of inorganic salts. The as‐prepared nanoparticles have a ceria cubic structure, up to x = 0.35, or are amorphous. Heat‐treatment is carried out at temperatures ranging from 500 to 800 °C, the latter temperature begin suitable to obtain solid solutions throughout the composition range. For all the heating temperatures and x values, the fluorite cubic structure of pure CeO2 transforms to a mixture (c′) of the cubic c and tetragonal t″ phases for x = 0.35, and to tetragonal t phase only for x = 0.8 at 650 °C, x = 0.65 at 800 °C, and, to a very limited extent, x = 0.5 at 1000 °C. No evidence is obtained at low x values of the t phase, which is detrimental to the oxygen storage capacity. Prolonged heating at 1000 °C demonstrates that only for x = 0.65 a limited separation of CeO2‐rich nanocrystals occurs. The samples undergo the same transition without simultaneous occurrence of different phases, apart for the two mentioned limited cases. This result is attributed to the intimate mixing of the metal cations even in the early stages of processing. In as‐prepared samples the Zr distribution becomes inhomogeneous when going from x = 0.2 to x = 0.35, but no early phase separations appear. The oxygen storage capacity is favorably influenced by the persistence of the cubic c′ phase.
Tuning of Regioselectivity in Inorganic Iodide‐Catalyzed Alkylation of 2‐Methoxyfurans via Electronic and Steric Effects
Authors: Chen Jie , Ni Shengjun , Ma Shengming
Published: April 2012

In the presence of inorganic iodide, the methoxy CO bond in 2‐methoxyfurans may be cleaved to afford the corresponding lactonic anion. Due to the presence of an electron‐withdrawing group at the 3‐position, the alkylation with normal organic iodides occurred at the 3‐position highly regioselectively. However, when electron‐deficient allylic iodides with an electron‐withdrawing group at the 2‐position were used the 5‐alkylation products were formed as the major products with sodium iodide as the catalyst. With magnesium iodide as the catalyst, the 5‐allylation occurred highly regioselectively. As a whole, the 3‐ vs. 5‐alkylation selectivity may be determined by the relative steric hindrance at the 3‐ and 5‐positions and the electronic effect of the allylic iodides. A rationale was proposed.
Ligand‐Free Buchwald–Hartwig Aromatic Aminations of Aryl Halides Catalyzed by Low‐Leaching and Highly Recyclable Sulfur‐Modified Gold‐Supported Palladium Material
Authors: Al‐Amin Mohammad , Honma Tetsuo , Hoshiya Naoyuki , Shuto Satoshi , Arisawa Mitsuhiro
Published: April 2012

A stable heterogeneous catalyst precursor, sulfur‐modified gold‐supported palladium material (SAPd), has proved to be an excellent source of leached, ligand‐free, Pd for the amination of aryl bromides and chlorides. The reaction‐enabling catalyst is provided in situ as leached Pd in low catalyst loading (0.21±0.02 mol%). This allows the precatalyst (SAPd) to be filtered off and used for a minimum of ten reaction cycles without loss of catalytic activity. SAPd released only trace amounts, less than 0.6 ppm, of highly active Pd during the reaction without any aggregation.
Copper‐Catalyzed Ultrasound‐Expedited N‐Arylation of Sulfoximines using Diaryliodonium Salts
Authors: Vaddula Buchireddy , Leazer John , Varma Rajender S.
Published: April 2012

An ultrasound‐accelerated route for an expeditious N‐arylation of NH‐sulfoximines is described that involves the use of diaryliodonium salts in aqueous polyethylene glycol‐400 and copper(I) bromide as catalyst at room temperature. The high yields of the products and simple work‐up are the highlights of the protocol.
Beyond the Limits: Palladium‐N‐Heterocyclic Carbene‐Based Catalytic System Enables Highly Efficient [4+2] Benzannulation Reactions
Authors: Zatolochnaya Olga V. , Galenko Alexey V. , Gevorgyan Vladimir
Published: April 2012

A highly efficient catalytic system for the palladium‐catalyzed [4+2] benzannulation reaction of enynes and enynophiles has been developed. The use of an N‐heterocyclic carbene‐based palladium precursor allowed us to achieve turnover numbers up to 1800. The new catalytic system has enabled an expansion of the scope of the [4+2] homo‐benzannulation reaction.
Tailoring Electrode/Electrolyte Interfacial Properties in Flexible Supercapacitors by Applying Pressure
Authors: Masarapu Charan , Wang Lian‐Ping , Li Xin , Wei Bingqing
Published: April 2012

Electrode/electrolyte interfacial properties of flexible supercapacitors assembled with nanostructured activated carbon fabric (ACF) electrodes can be tailored by applying a pressure and tuning electrolyte ion size relative to electrode pore size. Experimental results reveal that increasing pressure between the supercapacitor electrodes can significantly improve capacitive performance. The ratio of solvated ion size in the electrolyte to the pore size on the electrodes determines the minimum pressure necessary to achieve an optimum performance. For a specific electrode material, this minimum pressure for optimum performance is primarily governed by the size of the larger solvated ions (either the anions or cations), and is lower (∼689 KPa) when the ratio of the solvated ion size to the pore size is higher than 0.6, and is higher (at least 1379 KPa) when the ratio is lower than 0.6. An analytical model capable of predicting the experimental performance data has been developed. These results together provide a fundamental understanding of pressure dependence of electrode/electrolyte interfacial properties and pave the way for practical applications of flexible supercapacitors.
Are Large and Complex Agricultural Cooperatives Losing Their Social Capital?
Authors: Nilsson Jerker , Svendsen Gunnar L.H. , Svendsen Gert Tinggaard
Published: April 2012

During the last 20 years many traditionally organized agricultural cooperatives have been forced to abandon their business form. Explanations have been put forward, comprising a variety of economic and sociological theories. The present study suggests that the social capital paradigm may add explanatory power when analyzing this development. It is claimed that the problems are due to the members having increasingly little trust in the cooperatives and in each other. The cooperatives’ decision makers have no instruments for estimating how much social capital is lost when they pursue strategies of vertical and horizontal integration. Therefore, they do not consider this loss in their calculations. Thus, the problems caused by the cooperatives’ vaguely defined property rights are becoming increasingly serious. This reasoning is summarized into a model, which is influenced by the consumer choice model.[EconLit Classification; A130; P130; Q130].
Vertical Relationships in the Ready‐to‐Eat Breakfast Cereal Industry in Boston
Authors: Chidmi Benaissa
Published: April 2012

This study examines the vertical relationship between manufacturers and retailers in the ready‐to‐eat cereal (RTEC) industry in Boston. More precisely, the questions to be answered are, “What kind of vertical relationship exists between the manufacturers and the retailers?” “Does this relationship support the high price‐cost margins in the RTEC industry?” The results indicate that the RTEC manufacturers have the pricing decisions and that the retailers do not intervene in setting the retail prices for breakfast cereal brands. This is consistent with the vertical restraints theory that helps the manufacturers eliminate the externality created by the double marginalization scenario and an excessive demand contraction. [JEL Codes: L11, L13, L66].
Effect of styrene butadiene latex polymer contents on the bond properties of macro polypropylene fiber in polymer‐modified cement‐based composites
Authors: Park Chan‐Gi , Lee Jin‐Hyung
Published: April 2012

Because of its hydrophobicity, macro polypropylene (PP) fiber does not bond well in cement‐based composites and can reduce the mechanical properties. This study evaluated the influence of styrene–butadiene latex polymer (0–25 wt %) on the bonding of macro PP fiber in these composites. Bond strength was determined using dog‐bone test specimens compliant with JCI SF‐8. The bond strength of macro PP fiber improved with increasing styrene–butadiene latex polymer (latex) content up to 15%. The elastic behavior of the precrack zone increased, and interface toughness increased because the debonded zone was strong after crack formation. For latex content above 20%, the latex retarded the hydration reaction due to the absorption of latex into cement particles. This resulted in bond strengths that were lower than those for composites prepared with up to 15% latex content. Microstructural analysis of the macro PP fiber revealed that the amount of scratches also increased with increasing latex content up to 15%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of solvent interactions on the structure and properties of prepared PAni nanofibers
Authors: Pramanik Sujata , Karak Niranjan , Banerjee Somik , Kumar Ashok
Published: April 2012

The changes of structure and properties of nanofibers were studied as a function of solubility parameters of the organic solvents that are used in interfacial polymerization of polyaniline (PAni) nanofibers. The presence of UV–visible absorbance at 340, 440, and 800 nm confirmed the formation of emeraldine salt structure of the prepared PAni nanofibers. Fourier transform infrared spectral results indicate an increasing trend of benzenoid to quinoid ratio with the decrease of interaction of the solvents with aniline. This can be correlated to the increase in the degree of conjugation of the polymer chain. Photoluminescence study revealed an increase in the density of defect state with the decrease of interaction. Single‐line approximation technique was used to analyze the broadening of the most intense X‐ray reflection peak corresponding to (110) plane of the nanofibers. The greater the solvent–monomer interaction, the lesser was the domain length and π‐stacking of the PAni chains. The study of this interaction is instrumental to precisely control the internal conformation of the PAni nanofibers. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of annealing treatment on the structure and properties of polyurethane/multiwalled carbon nanotube nanocomposites
Authors: Jiang Fengdan , Zhang Liqun , Jiang Yi , Lu Yonglai , Wang Wencai
Published: April 2012

The thermoplastic polyurethane/multiwalled carbon nanotube (TPU/CNT) nanocomposites with high conductivity and low percolation threshold value were prepared by melting blending and annealing treatment. The effect of annealing process on the microphase structure and the properties of TPU/CNT nanocomposites was studied. It has been shown that CNT flocculation can occur in TPU/CNT nanocomposites during the annealing process. At a critical CNT content, which defined the percolation threshold, CNTs could form conductivity network. The conductive percolation threshold value of TPU/CNT nanocomposites was decreased from 10 to 4% after annealing process, and the conductivity of TPU/CNT nanocomposites with 10 vol % of CNT could reach 1.1 S/m after an annealing time of 1 h. The significant enhancement of electrical conductivity was influenced by the annealing time and the content of CNTs. The formation of CNT networks was also verified by dynamic viscoelastic characterization. The results of X‐ray diffraction and differential scanning calorimetry indicated that annealing process reinforced the microphase separation of the nanocomposites. Mechanical properties test showed that the annealing treatment was in favor of improving the mechanical properties; however, further increase in the annealing time has negative effect on the mechanical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study on short glass fiber‐reinforced poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) composites
Authors: Yu Zhifang , Yang Yaya , Zhang Linlin , Ding Yongchao , Chen Xiangming , Xu Kaitian
Published: April 2012

Biobased non‐fossil polyester poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) (P3/4HB) containing 4.0 mol % 4‐hydroxybutyrate (4HB) was melt‐mixed with short glass fibers (SGF) via a co‐rotating twin‐screw extruder. The compositing conditions, average glass fiber length and distribution, thermal, crystallization, and mechanical properties of the P3/4HB/SGF composites were investigated. Calcium stearate, two kinds of paraffin wax and modified ethylene bis‐stearamide (TAF) were investigated as lubricants for the P3/4HB/SGF composites. It revealed that TAF is the most efficient lubricant of the P3/4HB/SGF composites. Coupling agents 2,2′‐(1,3‐phenylene)bis‐2‐oxazoline (1,3‐PBO) and pyromellitic dianhydride (PMDA) were used as end‐group crosslinkers to reduce the degradation of P3/4HB and increase the mechanical properties of the P3/4HB/SGF composites. It showed that 1,3‐PBO is the efficient coupling agent. The optimum condition of the P3/4HB/SGF composites is 1.5 phr TAF, 1.0 phr 1,3‐PBO, and 30 wt % glass fiber content. And the maximum of tensile strength, tensile modulus, and impact strength of the composites is 3.7, 6.6, 1.8 times of the neat P3/4HB polymer, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Sugarcane bagasse composites from vegetable oils
Authors: Quirino Rafael L. , Larock Richard C.
Published: April 2012

Sugarcane bagasse composites have been prepared by the free radical polymerization of regular or modified vegetable oils with divinylbenzene and n‐butyl methacrylate in the presence of dried, ground sugarcane bagasse. Various cure times and temperatures have been investigated to determine the optimum cure sequence for the new materials. The postcure time has also been varied, and an ideal postcure treatment of 1 h at 180°C at ambient pressure has given the best overall properties. The effect of varying the filler load and resin composition has been assessed by means of tensile tests, dynamic mechanical analysis, thermogravimetric analysis, Soxhlet extraction, followed by proton nuclear magnetic resonance spectroscopic analysis of the extracts, and scanning electron microscopy. It has been observed that the initial washing and drying of the filler influence the filler–resin interaction and impact the final properties of the composites. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Role of compatibilizers on the physicomechanical performance of tea dust polypropylene composites
Authors: Hassan M. Masudul , Mueller Marco , Tartakowska Diana J. , Wagner Manfred H.
Published: April 2012

Tea dust (TD) polypropylene (PP) biocomposites and glycidyl methacrylate (GMA)‐grafted PP (GMA‐g‐PP) were manufactured using Brabender (PL‐2000, Plasti‐Corder, Germany) and hot press machine. The effects of fiber loading and the role of compatibilizer like maleic anhydride‐grafted PP (MAH‐g‐PP) and GMA‐g‐PP on morphology and physicomechanical properties of the TD‐reinforced PP biocomposites were investigated. On preliminary observation, it is found that the tensile strength of the biocomposites increased with increasing fiber content and presence of the compatibilizer at a certain limit. Scanning electron microscopic studies revealed that the dispersion of fiber in the matrix became worse with increasing fiber content but improved with addition of compatibilizer. The improved mechanical properties of the biocomposites correspond to the presence of the compatibilizer, which is attributed to interactions between hydroxyl groups in the filler and epoxy groups in GMA‐g‐PP and carboxylic group in MAH‐g‐PP. Swelling properties and biodegradable behavior test of the composites have also been performed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
New petroleum absorbers based on lignin‐CNSL‐formol magnetic nanocomposites
Authors: Grance E. G. O. , Souza F. G. , Varela A. , Pereira E. D. , Oliveira G. E. , Rodrigues C. H. M.
Published: April 2012

A magnetic resin based on lignin produced using the Kraft process was prepared and characterized. The material, because of its aromatic/aliphatic balance, can be used in oil‐spill clean‐up processes. The resin was prepared through bulk polycondensation of lignin, cashew nutshell liquid, and formaldehyde in the presence of maghemite nanoparticles. The obtained magnetic composites were studied by Fourier transform infrared spectroscopy, X‐ray diffraction, and Small‐angle X‐ray scattering. Cure degree, magnetic force, and oil removal capability tests were also performed. The results show that the composites possess an elevated cure degree, besides a considerable magnetic force. The materials exhibit a good oil removal capability—the composite containing 3.3 vol % of maghemite can remove 11 parts of oil from water. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Quantification of human hepatocyte cytochrome P450 enzymes and transporters induced by HIV protease inhibitors using newly validated LC‐MS/MS cocktail assays and RT‐PCR
Authors: Liu Li , Mugundu Ganesh M. , Kirby Brian J. , Samineni Divya , Desai Pankaj B. , Unadkat Jashvant D.
Published: April 2012

Human immunodeficiency virus (HIV) protease inhibitors (PIs) produce profound and unpredictable drug–drug interactions (DDIs) that cannot be explained fully by their inhibition/inactivation of CYP3A enzymes. Delineating and quantifying the CYPs and transporters inducible by PIs are crucial in developing an integrative mechanistic understanding and prediction of PI‐based DDIs. To do so, two LC‐MS/MS cocktail assays were modified and validated simultaneously to quantify the CYP activity of CYP3A, 2B6, 2C8, 2C9, 2C19, 1A, 2E1, 2A6 and 2D6 enzymes. These new assays were applied to evaluate the induction potential of eight PIs in microsomes isolated from PI‐treated human hepatocytes. The mRNA expression of these CYPs and transporters (OATP1B1, OATP1B3, OATP1A2, MDR1, MRP2 and MRP4) was also evaluated using relative RT‐PCR. The majority of PIs were net inducers of CYP3As and 2B6 at both the mRNA and activity level (> 2‐fold), while ritonavir, saquinavir, nelfinavir or lopinavir did not induce CYP3A activity (< 2‐fold), presumably due to CYP3A inactivation. OATP1B1 and MDR1 were the only two hepatic transporters induced (> 2‐fold) by the PIs. Amprenavir was the most potent net inducer. In conclusion, our validated cocktail assays can be implemented to comprehensively quantify CYP activities in human liver microsomes and hepatocyte studies. The results also provide the much needed data on the net induction potential of the PIs for hepatic CYPs and transporters. A qualitative agreement was observed between our results and published PI‐based DDIs, suggesting that human hepatocytes are a useful platform for more extensive and quantitative in vitro–in vivo prediction of PI‐based DDIs. Copyright © 2012 John Wiley & Sons, Ltd.
Vanadium Catalyzed Synthesis of Cyclic Organic Carbonates
Authors: Coletti Alessia , Whiteoak Christopher J. , Conte Valeria , Kleij Arjan W.
Published: April 2012

Vanadium complexes bearing easily synthesized, differently functionalized salen and salphen ligands were prepared and tested for their ability to catalyze the cycloaddition of carbon dioxide to epoxides resulting in cyclic organic carbonates. The reactivity of the prepared catalysts dramatically increases when a coordinating hydroxyl group is present as a substituent in the organic epoxide. The commercially available [VO(acac)2] complex was used as reference compound, and, in this case, we found that V10O26⋅(NBu4)4 was formed during the catalytic reactions. This compound, characterized by X‐ray diffraction analysis, is likely the active catalyst, and it results in significantly better yields of cyclic carbonates compared to those obtained with Schiff base containing vanadyl complexes. The high activity of the mixed polyoxo vanadyl‐vanadate complex marks it as a powerful catalyst within the context of CO2 fixation chemistry.
Electrochemistry of Nanocrystalline 3C Silicon Carbide Films
Authors: Yang Nianjun , Zhuang Hao , Hoffmann René , Smirnov Waldemar , Hees Jakob , Jiang Xin , Nebel Christoph E.
Published: April 2012

Silicon carbide (SiC) films have been used frequently for high‐frequency and powder devices but have seldom been applied as the electrode material. In this paper, we have investigated the electrochemical properties of the nanocrystalline 3C‐SiC film in detail. A film with grain sizes of 5 to 20 nm shows a surface roughness of about 30 nm. The resistivity of the film is in the range of 3.5–6.2 kΩ cm. In 0.1 M H2SO4 solution, the film has a double‐layer capacitance of 30–35 μF cm−2 and a potential window of 3.0 V if an absolute current density of 0.1 mA cm−2 is defined as the threshold. Its electrochemical activity was examined by using redox probes of [Ru(NH3)6]2+/3+ and [Fe(CN)6]3−/4− in aqueous solutions and by using redox probes of quinone and ferrocene in nonaqueous solutions. Diffusion‐controlled, quasi‐reversible electrode processes were achieved in four cases. The surface chemistry of the nanocrystalline 3C‐SiC film was studied by electrochemical grafting with 4‐nitrobenzenediazonium salts. The grafting was confirmed by time‐of‐flight secondary ion mass spectroscopy. All these results confirm that the nanocrystalline 3C‐SiC film is promising for use as an electrode material.
Continuous‐Flow Reactor‐Based Enzymatic Synthesis of Phosphorylated Compounds on a Large Scale
Authors: Babich Lara , Hartog Aloysius F. , van der Horst Michael A. , Wever Ron
Published: April 2012

Acid phosphatase, an enzyme that is able to catalyze the transfer of a phosphate group from cheap pyrophosphate to alcoholic substrates, was covalently immobilized on polymethacrylate beads with an epoxy linker (Immobeads‐150 or Sepabeads EC‐EP). After immobilization 70 % of the activity was retained and the immobilized enzyme was stable for many months. With the immobilized enzyme we were able to produce and prepare D‐glucose‐6‐phosphate, N‐acetyl‐D‐glucosamine‐6‐phosphate, allyl phosphate, dihydroxyacetone phosphate, glycerol‐1‐phosphate, and inosine‐5′‐monophosphate from the corresponding primary alcohol on gram scale using either a fed‐batch reactor or a continuous‐flow packed‐bed reactor.
Composition‐Tunable Pt–Co Alloy Nanoparticle Networks: Facile Room‐Temperature Synthesis and Supportless Electrocatalytic Applications
Authors: Xu You , Yuan Yongqiang , Ma Aijing , Wu Xuan , Liu Yang , Zhang Bin
Published: April 2012

Pt–Co alloy nanoparticle networks (NNs) with adjustable composition are synthesized by co‐reduction of H2PtCl6 and CoCl2 with NaBH4 in an ethylene glycol assisted cetyltrimethylammonium bromide/water/chloroform system at room temperature. Electrochemical measurements indicate that the as‐prepared spongelike Pt–Co NNs exhibit composition‐dependent electrocatalytic activities and CO tolerance with better durability toward methanol and formic acid oxidation than commercially available Pt/C catalyst. In particular, Pt3Co NNs show the highest specific activity, while Pt2Co NNs exhibit optimal mass activity among Pt–Co alloy NNs with different composition. These Pt–Co alloy NNs may be promising supportless anode catalysts for the direct methanol and direct formic acid fuel cells.
Bonding of Gold with Unsaturated Species
Authors: Nava Paola , Hagebaum‐Reignier Denis , Humbel Stéphane
Published: April 2012

Interactions of gold(I) catalysts with alkenes and alkynes are analyzed. Neutral chlorido, and cationic phosphine and N‐heterocyclic carbene complexes are studied. High‐level ab initio calculations are performed to benchmark the accuracy of popular DFT methods. Donation and backdonation contributions in the bond between the gold fragment and the alkene/alkyne substrate are discussed. These contributions depend on the nature of the gold fragment, but also on the substituents on the alkene/alkyne.
Regeneration of Silica‐Supported Silicotungstic Acid as a Catalyst for the Dehydration of Glycerol
Authors: Katryniok Benjamin , Paul Sébastien , Capron Mickaël , Bellière‐Baca Virginie , Rey Patrick , Dumeignil Franck
Published: April 2012

The dehydration reaction of glycerol to acrolein is catalyzed by acid catalysts. These catalysts tend to suffer from the formation of carbonaceous species on their surface (coking), which leads to substantial degradation of their performances (deactivation). To regenerate the as‐deactivated catalysts, various techniques have been proposed so far, such as the co‐feeding of oxygen, continuous regeneration by using a moving catalytic bed, or alternating between reaction and regeneration. Herein, we study the regeneration of supported heteropolyacid catalysts. We show that the support has a strong impact on the thermal stability of the active phase. In particular, zirconia has been found to stabilize silicotungstic acid, thus enabling the nondestructive regeneration of the catalyst. Furthermore, the addition of steam to the regeneration feed has a positive impact by hindering the degradation reaction by equilibrium displacement. The catalysts are further used in a periodic reaction/regeneration process, whereby the possibility of maintaining long‐term catalytic performances is evidenced.
Evidence of environmental niche differentiation in the striped mouse (Rhabdomyssp.): inference from its current distribution in southern Africa
Authors: Meynard Christine N. , Pillay Neville , Perrigault Manon , Caminade Pierre , Ganem Guila
Published: April 2012

The aim of this study was to characterize environmental differentiation of lineages withinRhabdomysand provide hypotheses regarding potential areas of contact between them in the Southern African subregion, including the Republic of South Africa, Lesotho, and Namibia. Records ofRhabdomystaxa across the study region were compiled and georeferenced from the literature, museum records, and field expeditions. Presence records were summarized within a 10 × 10 km grid covering the study area. Environmental information regarding climate, topography, land use, and vegetation productivity was gathered at the same resolution. Multivariate statistics were used to characterize the current environmental niche and distribution of the whole genus as well as of three mitochondrial lineages known to occur in southern Africa. Distribution modeling was carried out using MAXENT in order to generate hypotheses regarding current distribution of each taxa and their potential contact zones. Results indicate that the two species withinRhabdomysappear to have differentiated across the precipitation/temperature gradient present in the region from east to west.R. dilectusoccupies the wettest areas in eastern southern Africa, whileR. pumiliooccupies the warmer and drier regions in the west, but also penetrates in the more mesic central part of the region. We provide further evidence of environmental differentiation within two lineages ofR. dilectus. Contact zones between lineages appear to occur in areas of strong environmental gradients and topographic complexity, such as the transition zones between major biomes and the escarpment area where a sharp altitudinal gradient separates coastal and plateau areas, but also within more homogeneous areas such as within grassland and savannah biomes. Our results indicate thatRhabdomysmay be more specialized than previously thought when considering current knowledge regarding mitochondrial lineages. The genus appears to have differentiated along two major environmental axes in the study region, but results also suggest dispersal limitations and biological interactions having a role in limiting current distribution boundaries. Furthermore, the projection of the potential geographic distribution of the different lineages suggests several contact zones that may be interesting study fields for understanding the interplay between ecological and evolutionary processes during speciation.
The juvenile social environment introduces variation in the choice and expression of sexually selected traits
Authors: Kasumovic Michael M. , Hall Matthew D. , Brooks Robert C.
Published: April 2012

The juvenile environment provides numerous cues of the intensity of competition and the availability of mates in the near environment. As research demonstrates that the developing individuals can use these cues to alter their developmental trajectories, and therefore, adult phenotypes, we examined whether social cues available during development can affect the expression and the preference of sexually selected traits. To examine this, we used the Australian black field cricket (Telogryllus commodus), a species where condition at maturity is known to affect both male calling effort and female choice. We mimicked different social environments by rearing juveniles in two different densities crossed with three different calling environments. We demonstrate that the social environment affected female response speed but not preference, and male age‐specific calling effort (especially the rate of senescence in calling effort) but not the structural/temporal parameters of calls. These results demonstrate that the social environment can introduce variation in sexually selected traits by modifying the behavioral components of male production and female choice, suggesting that the social environment may be an overlooked source of phenotypic variation. We discuss the plasticity of trait expression and preference in reference to estimations of male quality and the concept of condition dependence.
Disaccharide‐Containing Macrocycles by Click Chemistry and Intramolecular Glycosylation
Authors: Tiwari Vinod K. , Kumar Amit , Schmidt Richard R.
Published: April 2012

In this study o‐ and m‐xylylene moieties in combination with a triazolylmethyl moiety have been successfully employed as a relatively rigid spacer system in intramolecular glycosylation reactions. Phenyl 3,4,6‐tri‐O‐benzyl‐2‐O‐propargyl‐1‐thio‐D‐glucopyranoside was employed as a donor, which could be readily connected by 1,3‐dipolar cycloaddition (click reaction) to O‐(2‐ or 3‐azidomethylbenzyl)‐protected acceptors to afford, after liberation of the accepting hydroxy groups, the desired donor–spacer–acceptor‐linked intermediates. NIS/TMSOTf‐promoted glycosylation furnished disaccharide‐containing macrocycles. In general, very good results were obtained. The anomeric selectivity is dependent on various factors, the ring size seeming crucial.