bluuebunny/crossref_metadata_2025 huggingface dataset:
Baseflow simulation using SWAT model in an inland river basin in Tianshan Mountains, Northwest China
Authors: Luo Y. , Arnold J. , Allen P. , Chen X.
Published: April 2012

Abstract. Baseflow is an important component in hydrological modeling. The complex streamflow recession process complicates the baseflow simulation. In order to simulate the snow and/or glacier melt dominated streamflow receding quickly during the high-flow period but very slowly during the low-flow period in rivers in arid and cold northwest China, the current one-reservoir baseflow approach in SWAT (Soil Water Assessment Tool) model was extended by adding a slow- reacting reservoir and applying it to the Manas River basin in the Tianshan Mountains. Meanwhile, a digital filter program was employed to separate baseflow from streamflow records for comparisons. Results indicated that the two-reservoir method yielded much better results than the one-reservoir one in reproducing streamflow processes, and the low-flow estimation was improved markedly. Nash-Sutcliff efficiency values at the calibration and validation stages are 0.68 and 0.62 for the one-reservoir case, and 0.76 and 0.69 for the two-reservoir case. The filter-based method estimated the baseflow index as 0.60, while the model-based as 0.45. The filter-based baseflow responded almost immediately to surface runoff occurrence at onset of rising limb, while the model-based responded with a delay. In consideration of watershed surface storage retention and soil freezing/thawing effects on infiltration and recharge during initial snowmelt season, a delay response is considered to be more reasonable. However, a more detailed description of freezing/thawing processes should be included in soil modules so as to determine recharge to aquifer during these processes, and thus an accurate onset point of rising limb of the simulated baseflow.
The earthquake sedimentary record in the western part of the Sea of Marmara, Turkey
Authors: Drab L. , Hubert Ferrari A. , Schmidt S. , Martinez P.
Published: April 2012

Abstract. The submarine part of the North Anatolian Fault (NAF) is a very significant hazard for the 12 million people living in Istanbul (Turkey). An accurate seismic risk assessment necessitates paleoseismological data, which can be retrieved in the Marmara Sea by using sedimentary cores. Here, a record of turbidites was obtained in five cores, spanning the Tekirdağ Basin, the Western High and the Central Basin linked by the Tekirdağ fault segment. The turbidites are synchronous at different sites across the two basins and through the structural high pointing to shaking by earthquakes as a triggering mechanism. In particular, the M = 7.4 1912 Mürefte earthquake left a distinctive sedimentary imprint in all the studied cores. Radiocarbon dating implies a turbidite recurrence interval of about 300 yr. The low number of seismo-turbidites documented in the Central Basin compared to the Tekirdağ Basin suggests quasi-synchronous ruptures of the Tekirdağ Segment and the adjacent Central Segment of the NAF or a partial seismic slip on the Central Segment. Both scenarios have implications regarding seismic hazard. Finally, though we obtained a paleoseismological record of the ruptures along the Tekirdağ Segment, further chronological constraints are needed to better date the events and to confirm the completeness of the obtained record.
Uterine Hemangioma: A Rare Pathologic Entity
Authors: Chou Wan-Yi , Chang Hui-Wen
Published: April 2012

Uterine hemangioma is a rare benign tumor usually presenting with menorrhagia or pregnancy-associated complications. Although the current literature identifies fewer than 50 cases, we in our institution identified 5 similar cases among 3700 patients undergoing total hysterectomy from January 2006 to December 2010. Adenomyosis was the most common preoperative diagnosis among our patients. Vaginal examination, uterine curettage specimens, ultrasonography, and hysterography are usually uninformative, and the definitive diagnosis relies on the final histologic examination. The differential diagnosis includes adenomatoid tumor, lymphangioma, and arteriovenous malformation. Uterine hemangiomas are classified into congenital and acquired. The former is believed to be associated with some hereditary diseases, while the latter is associated with both physical changes and hormone alteration, especially high estrogen level. The best treatment for hemangiomas is unclear. However, it is very important to obtain an accurate diagnosis to prevent overtreatment among reproductive-age women. The prognosis is excellent after hysterectomy.
Iron Overload in Allogeneic Hematopoietic Stem Cell Transplant Recipients
Authors: Ali Sharif , Pimentel Jason D. , Munoz Javier , Shah Veena , McKinnon Rick , Divine George , Janakiraman Nalini
Published: April 2012

Context.—Patients who undergo hematopoietic stem cell transplant are at an increased risk of developing iron overload.

Objectives.—To describe the effect of hepatic iron overload on hematopoietic stem cell transplant recipients and to validate the utility of histologic scoring system of iron granules in the liver.

Design.—Records of 154 post allogeneic hematopoietic stem cell transplant patients were reviewed. Forty-nine patients underwent liver biopsy. Histologic hepatic iron overload was defined as a score of 2 or greater (scale, 0–4).

Results.—Twenty-eight of 49 patients (57%) evaluated by liver biopsy had hepatic iron overload; 17 had moderate to severe hepatic iron overload (score, 3 or 4). In multivariate analysis, a significant correlation was discovered between hepatic iron overload and the number of transfusions (P < .001), posttransplant serum ferritin levels (P  =  .004), lactate dehydrogenase levels (P  =  .03), and the development of blood stream infections (P  =  .02). There was no correlation between hepatic iron overload and abnormal liver function test results. While 37 patients (76%) died after receiving a transplant, mortality was not influenced by hepatic iron overload but was significantly higher in older patients, in patients with lower serum albumin levels, higher serum bilirubin levels, and higher clinical grade of acute graft-versus-host disease (P  =  .04, P  =  .001, P  =  <.001, and P  =  .004, respectively).

Conclusions.—Hepatic iron overload is commonly identified in hematopoietic stem cell transplant patients and can be accurately diagnosed by liver biopsy. In addition, hepatic iron overload has been identified in patients receiving as few as 25 units of packed red blood cells, with elevated posttransplant serum ferritin levels, and with blood stream infections.
Quantitative Assessment and Classification of Tissue-Based Biomarker Expression With Color Content Analysis
Authors: Keller Brad , Chen Weijie , Gavrielides Marios A.
Published: April 2012

Context.—The use of computer aids has been suggested as a way to reduce interobserver variability that is known to exist in the interpretation of immunohistochemical staining in pathology. Such computer aids should be automated in their usage but also they should be trained in an automated and reproducible fashion.

Objective.—To present a computer aid for the quantitative analysis of tissue-based biomarkers, based on color content analysis.

Design.—The developed system incorporates an automated algorithm to allow retraining based on the color properties of different training sets. The algorithm first generates a color palette containing the colors present in a training subset. Based on the palette, color histograms are derived and are used as feature vectors to a pattern recognition system, which returns an output proportional to biomarker continuous expression or a categorical classification. The method was evaluated on a database of HER2/neu digital breast cancer slides, for which expression scores from a pathologist panel were available. The system was retrained and evaluated on different transformations of the database, including compression, blurring, and changes in illumination, to examine its robustness to different imaging conditions frequently met in digital pathology.

Results.—Results showed high agreement between the results of the algorithm and the truth from the pathologist panel as well as robustness to image transformations.

Conclusions.—The results of the study are encouraging for the potential of this method as a computer aid to assess biomarker expression in a consistent and reproducible manner.
Reversible Fragmentation and Self‐Assembling of Nematic Liquid Crystal Droplets on Functionalized Pyroelectric Substrates
Authors: Merola Francesco , Grilli Simonetta , Coppola Sara , Vespini Veronica , De Nicola Sergio , Maddalena Pasquale , Carfagna Cosimo , Ferraro Pietro
Published: April 2012

Investigation on the behavior of nematic liquid crystals on functionalized polar dielectric crystal substrates is accomplished. Very interesting effects can be observed in maneuvering liquid crystal droplets on the substrate surface, driven by electric fields generated by pyroelectric effect. Reversible drops fragmentation and self‐assembling in different configurations can be achieved. The dynamics of the observed phenomena is studied and the repeatability of the process is full assessed.
A Metal‐Free Oxidative Esterification of the Benzyl CH Bond
Authors: Feng Jie , Liang Shuai , Chen Shan‐Yong , Zhang Ji , Fu Song‐Sen , Yu Xiao‐Qi
Published: April 2012

An efficient metal‐free oxidative esterification of benzyl CH bonds was developed. Using tetrabutylammonium iodide as catalyst and tert‐butyl hydroperoxide as co‐oxidant, benzylic substrates could react smoothly with various carboxylic acids to give the esters with good to excellent yields. The method was also suitable for the O‐protection of N‐Boc amino acids. The reaction mechanism was primarily investigated and a radical process was proposed.
Enantioselective Diynylation of Cyclic N‐Acyl Ketimines: Access to Chiral Trifluoromethylated Tertiary Carbinamines
Authors: Zhang Fa‐Guang , Ma Hai , Nie Jing , Zheng Yan , Gao Qingzhi , Ma Jun‐An
Published: April 2012

A novel enantioselective diynylation of cyclic N‐acyl trifluoromethylketimines with chloramphenicol‐amine derivatives as chiral additives has been successfully developed. A series of diynylated tertiary trifluoromethylcarbinamines were obtained in high yields with good to excellent enantioselectivities (with up to 99% ee).
Li4Ti5O12 Nanoparticles Embedded in a Mesoporous Carbon Matrix as a Superior Anode Material for High Rate Lithium Ion Batteries
Authors: Shen Laifa , Zhang Xiaogang , Uchaker Evan , Yuan Changzhou , Cao Guozhong
Published: April 2012

A mesoporous Li4Ti5O12/C nanocomposite is synthesized by a nanocasting technique using the porous carbon material CMK‐3 as a hard template. Modified CMK‐3 template is impregnated with Li4Ti5O12 precursor, followed by heat treatment at 750 °C for 6 h under N2. Li4Ti5O12 nanocrystals of up to several tens of nanometers are successfully synthesized in micrometer‐sized porous carbon foam to form a highly conductive network, as confirmed by field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Raman spectroscopy, and nitrogen sorption isotherms. The composite is then evaluated as an anode material for lithium ion batteries. It exhibits greatly improved electrochemical performance compared with bulk Li4Ti5O12, and shows an excellent rate capability (73.4 mA h g−1 at 80 C) with significantly enhanced cycling performance (only 5.6% capacity loss after 1000 cycles at a high rate of 20 C). The greatly enhanced lithium storage properties of the mesoporous Li4Ti5O12/C nanocomposite may be attributed to the interpenetrating conductive carbon network, ordered mesoporous structure, and the small Li4Ti5O12 nanocrystallites that increase the ionic and electronic conduction throughout the electrode.
Incidence of lymphoproliferative disorders in patients with celiac disease
Authors: Leslie Lori A. , Lebwohl Benjamin , Neugut Alfred I. , Gregory Mears John , Bhagat Govind , Green Peter H.R.
Published: April 2012

Prior studies describe an increased incidence of lymphoma in celiac disease. However, few studies differentiate among lymphoproliferative disorders (LPDs). Our aim was to determine incidences of LPD subtypes in celiac disease patients, describe patterns of celiac disease presentation in patients who develop LPD, and compare survival in patients with various LPD subtypes. We conducted a retrospective cohort study of adults with biopsy‐proven celiac disease seen at a US referral center from 1981 to 2010, identified patients with comorbid LPD, and calculated standardized incidence ratios (SIR) for each LPD subtype. In our cohort of 1,285 patients with celiac disease, there were 40 patients with LPD [SIR = 6.48, 95% confidence interval (CI) = 4.62–8.64] including 33 with non‐Hodgkin lymphoma (NHL, SIR = 6.91, 95% CI = 4.26–8.28). The incidences of NHL subtypes including enteropathy‐associated T‐cell (EATL, n = 12), non‐EATL T‐cell (SIR = 22.43, 95% CI = 7.08–46.41), diffuse large B‐cell (SIR = 5.37, 95% CI = 1.93–10.52), mantle cell (SIR = 32.21, 95% CI = 6.07–78.97), and marginal zone (SIR = 37.17, 11.73–76.89) lymphoma remained significantly elevated when only those diagnosed with celiac before LPD were considered (n = 24, NHL SIR = 4.47, 95% CI = 2.86–6.44). Patients who developed LPD were older at time of celiac disease diagnosis (57.9 ± 15.5 versus 42.5 ± 17.4 years, P < 0.0001) and more likely to present with diarrhea (60.0% versus 39.8% P = 0.016), abdominal pain (17.5% versus 5.5% P = 0.0046), and/or weight loss (12.5% versus 4.0%, P = 0.028). EATL patients had a shorter average survival than non‐EATL NHL patients (3.2 versus 15.0 years, P = 0.016). The incidence of LPD is increased in celiac disease patients. Those diagnosed later in life who present with symptoms of malabsorption are more likely to be diagnosed with LPD. Am. J. Hematol. 2012. © 2012 Wiley Periodicals, Inc.
Hepatitis B virus infection and waste collection: Prevalence, risk factors, and infection pathway
Authors: Rachiotis George , Papagiannis Dimitrios , Markas Dimitrios , Thanasias Efthimios , Dounias George , Hadjichristodoulou Christos
Published: April 2012

Background

Waste collectors have a potential risk of infectious diseases. The aim of the study was to assess; the prevalence of hepatitis B (HBV), risk factors for infection and possible ways of virus transmission among municipal solid waste workers (MSWWs) in a municipality of central Greece.

Methods

A cross‐sectional study was conducted among the employees of a municipality in Central Greece. The prevalence of an HBV infection biological marker (anti‐Hbc) and its association with exposure to waste, socio‐demographic factors, and history of occupational injuries with sharp objects/needle sticks was examined among 208 employees.

Results

The prevalence of HBV infection among the municipal waste collectors was 23%. Logistic regression analysis showed that exposure to waste (OR = 4.05;95%CI = 1.23–13.33) and age (OR = 5.22;95% CI = 1.35–20.1) were independently associated with the anti‐Hbc positivity. Moreover, waste collectors who reported occupational injuries with needle sticks were at higher risk of HBV infection (RR = 2.64; 95% CI = 1.01–6.96).

Conclusions

Occupational exposure to waste is a possible risk factor for HBV infection. Occupational injury with sharp instruments could be a means of hepatitis B virus transmission. Immunization of MSWWs and adoption of more safe ways for waste collection could be considered in order to control the risk of HBV infection. Am. J. Ind. Med. 55:650–655, 2012. © 2012 Wiley Periodicals, Inc.
Microsatellite Variation in Two Subspecies of Cynomolgus Monkeys (Macaca fascicularis)
Authors: Li Aixue , Sun Zhaozeng , Zeng Lin , Li Ruisheng , Kong Deqiang , Zhao Yanbin , Bai Jieying , Zhao Shuang , Shang Shichen , Shi Yansheng
Published: April 2012

To estimate the genetic variability of two subspecies of cynomolgus monkeys (Macaca fascicularis fascicularis and M. f. aurea) using microsatellite markers, 26 microsatellite markers were selected from previous reports. Seventeen markers showed high polymorphism in a subset of monkeys and were used for the assessment of genetic diversity in the larger sample. The effective number of alleles, the polymorphism information content (PIC) and the expected heterozygosity of M. f. aurea monkeys were all statistically significantly higher than those of M. f. fascicularis monkeys (P < 0.05), suggesting the M. f. aurea monkeys had a higher degree of genetic variation than the M. f. fascicularis monkeys. Substantial differences in allele distribution were also detected between the two subspecies of cynomolgus monkeys. Private alleles restricted to the M. f. fascicularis or the M. f. aurea monkeys were found throughout the selected 17 loci. These private alleles may allow the discrimination of the two subspecies of cynomolgus monkeys. The selected markers could also be used to estimate the genetic variation for other subspecies of cynomolgus monkeys. Further work using additional animals obtained from native or independent sources will be important for a more complete understanding of the genetic differences between these two subgroups. Am. J. Primatol. 74:561–568, 2012. © 2012 Wiley Periodicals, Inc.
Metal organic chemical vapor deposition of ZnO from β‐ketoiminates
Authors: Holmes Jordan , Johnson Keneshia , Zhang Bo , Katz Howard E. , Matthews Jason S.
Published: April 2012

ZnO is a high‐mobility electron conductor being considered for high‐throughput electronics in flexible and transparent formats. We demonstrated the Zn β‐ketoiminate system, based on acetylacetimine with N‐propyl, isopropyl, and butyl groups, as a vehicle for preparing ZnO thin films for electronic applications. Surface carbon was a primary impurity, and the precursors studied afforded films with the lowest surface carbon contamination at deposition temperatures near 400°C. Thermal annealing of the films reduced the surface carbon content and afforded semiconducting materials. Annealing also gave larger‐grained, better connected films. Thinner films were associated with semiconducting as opposed to ohmic behavior; such films will be adaptable for transparent logic circuits. Copyright © 2012 John Wiley & Sons, Ltd.
A new technique for preparation of PDMS/ceramic nanocomposite membrane for gaseous hydrocarbons separation
Authors: Jannatdoust E. , Babaluo A. A. , Abbasi F. , Akhfash Ardestani M. , Peyravi M.
Published: April 2012

A novel composite membrane using polydimethylsiloxane (PDMS) as a top active layer and ceramic nanocomposite as the support layer was developed for the gaseous hydrocarbons separation. For the fabrication of hybrid membranes, nanocomposite technology applied for manufacturing ceramic supports with controllable microstructures. Also, a new method was used for coating a uniform and no penetrated polymeric layer. Top layer of ceramic support with nanocomposite microstructures was fabricated using 5 wt % α‐Al2O3‐SiO2 bidispersed suspensions with optimum weight fraction of second phase (SiO2) based on the fractional collision frequency theory. PDMS selective layer was coated on the outer surface of the porous ceramic nanocomposite support by dip‐coating method. In this respect, the effect of several parameters such as pretreatment temperature, PDMS solution concentration, and number of coated polymeric layers on prepared layers morphology and hybrid membrane performance in the separation of condensable hydrocarbons (iso and n‐butane) from hydrogen were investigated. The results showed that the membranes fabricated at 140°C as pretreatment temperature and three polymeric layers by 7, 15, and 15 wt % PDMS concentration, respectively, had a high selectivity (>25 at 2 bar)) in C4H10/H2 separation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The influence of talc as a nucleation agent on the nonisothermal crystallization and morphology of isotactic polypropylene: The application of the Lauritzen–Hoffmann, Avrami, and Ozawa theories
Authors: Kocic Nikola , Kretschmer Karsten , Bastian Martin , Heidemeyer Peter
Published: April 2012

A new method is proposed, which can be used to analyze the influence of different additives and fillers on the nonisothermal crystallization of polymers. The composites of talc in isotactic polypropylene (i‐PP) were prepared using a corotating twin‐screw extruder. The compounds were subsequently dried and injection molded. PP morphology and talc dispersion were visualized using optical microscopy and computed tomography. Wide‐angle X‐ray scattering and small‐angle X‐ray scattering measurements provided an insight into the crystal structure of PP. The data obtained from nonisothermal DSC measurements were fitted to the Avrami model for the nonisothermal case. The calculated Avrami's exponent (n), which takes into account the influence of talc on the nucleation and growth of the PP crystals, was used in the combination of Lauritzen–Hoffman and Ozawa models to calculate the nucleation parameter (Kg). A good agreement was found between the model predictions and literature values. The examination shows that the developed model extension gives an expected trend in the case of i‐PP filled with talcs from the same origin but with different particle sizes. Furthermore, it is shown that delaminated talc with a higher specific surface is more efficient in nucleation of i‐PP. Thus, the introduced model extension could be a useful tool for comparing of nucleation ability of different additives in the crystallization of polymers. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles
Authors: Rivero Pedro J. , Urrutia Aitor , Goicoechea Javier , Rodríguez Yoany , Corres Jesús M. , Arregui Francisco J. , Matías Ignacio R.
Published: April 2012

This work presents an alternative approach for fabricating electrospun submicron highly hydrophilic fiber mats loaded with silver nanoparticles. These fiber mats show a high efficient antibacterial behavior, very attractive for applications like wound healing and skin regeneration processes. The fabrication method is divided in two steps. First, poly(acrylic acid) (PAA) and β‐cyclodextrin (β‐CD) submicron fibers were electrospun and further stabilized using a thermal treatment, yielding stable hydrogel‐like fibers with diameters ranging from 100 nm up to several microns. In the second step, silver ions were loaded into the fibers and then reduced to silver nanoparticles in‐situ. The electrospinning parameters were adjusted to achieve the desired properties of the fiber mat (density, size) and afterwards, the characteristics of the silver nanoparticles (amount, size, aggregation) were tuned by controlling the silver ion loading mechanism. Highly biocide surfaces were achieved showing more than 99.99% of killing efficiency. The two‐step process improves the reproducibility and tunability of the fiber mats. To our knowledge, this is the first time that stable hydrogel fibers with a highly biocide behavior have been fabricated using electrospinning. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis and crosslinking behavior of a soluble, crosslinkable, and high young modulus poly(arylene ether nitriles) with pendant phthalonitriles
Authors: Yang Jian , Yang Xulin , Zou Yanke , Zhan Yingqing , Zhao Rui , Liu Xiaobo
Published: April 2012

Poly(arylene ether nitriles) (PEN) with pendant phthalonitrile groups (PENCN) were obtained via the Yamazaki‐Higashi phosphorylation route of 4‐(4‐aminophenoxy)phthalonitrile (APN) with acid‐contained PEN (PENCOOH) in the presence of CaCl2. The chemical structure and molecular weight of PENCN were characterized by 1H‐NMR, Fourier transform infrared spectroscopy, and Gel permeation chromatography. The synthesized PENCN had superior solubility in polar organic solvent and can be easily processed into thin films from the solutions of N‐methylpyrrolidone, dimethylsulfoxide, N,N′‐dimethylformamide, dimethylacetamide, and tetrahydrofuran. Compared with PENCOOH, PENCN showed higher thermal stability with 5% weight loss temperatures (T5%) up to 430°C. The glass transition temperature of PENCN was improved from 211 to 235°C measured by differential scanning calorimetry (DSC). In addition, it also exhibited excellent mechanical properties that Young's modulus reached to 3.5 GPa. Meanwhile, the effects of different aromatic amines and Lewis acid on the crosslinking behavior of PENCN were investigated by DSC. The results indicated that anhydrous Zinc chloride (ZnCl2) was the best catalyst to lower the curing temperature among 2,6‐bis(4‐diaminobenzoxy) benzonitrile, 4,4‐diaminediphenyl sulfone, APN and ZnCl2. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Surface modification of carbon fiber and the mechanical properties of the silicone rubber/carbon fiber composites
Authors: Kim Eung Soo , Lee Tae Hwa , Kim Eun Jeong , Yoon Jin‐San
Published: April 2012

Effects of the incorporation of the PAN‐based carbon fiber (CF) into a room temperature vulcanized silicone rubber (RTV), poly(dimethylsiloxane) (PDMS) containing terminal silanol groups, on the thermal stability and mechanical properties were explored. CF was modified with nitric acid to introduce hydroxyl and carboxyl groups on the CF surface. These functional groups were then treated with an isocyanato silane compound, 3‐isocyanatopropyltriethoxysiane (IPTS) to incorporate trialkoxy groups to the acid‐treated CF to prepare IPTS grafted CF (I‐CF). The alkoxy groups on the surface of I‐CF may undergo the condensation reaction with the silanol groups of RTV to enhance the interfacial interaction between I‐CF and RTV. Morphology of the fractured surface of RTV/CF composites was examined by scanning electron microscopy (SEM). The mechanical properties and thermal stability of the composites were analyzed and rationalized by the increase in the degree of curing of RTV and the enhanced interfacial interaction. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical, morphological, and thermal properties of chemically treated pine needles reinforced thermosetting composites
Authors: Singha Amar Singh , Jyoti Aishwarya
Published: April 2012

Natural fibers are widely used as reinforcement in composites. Pine needles are one of the major biowaste generated by Pinus roxburgii plant. This species is found abundantly in the forests of Himachal Pradesh. In this work, composites of urea–resorcinol–formaldehyde resin‐reinforced with Pine needles fibers were prepared. Fibers were chemically modified to improve their compatibility with matrix. These fibers were mercerized with NaOH solution and acetylated to increase their hydrophobic character. The chemically modified fibers were characterized with Fourier transform infrared spectra, 13C‐nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy. The composites were prepared with treated and untreated fibers containing 30% fibers by weight using compression molding technique. The morphology of the materials thus obtained was evaluated by scanning electron microscopy. The chemical modifications of fibers improve fiber–matrix adhesion and also have markedly effect on mechanical properties of composites. Moreover, the thermal resistance of these composites was improved on chemical modification. These results indicate that chemically modified fibers exhibit better compatibility with the polymer matrix than that of untreated fiber. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci, 2013
Study of uranium adsorption using amidoximated polyacrylonitrile‐encapsulated macroporous beads
Authors: Singh Krishankant , Shah Chetan , Dwivedi Charu , Kumar Manmohan , Bajaj Parma N.
Published: April 2012

Polyacrylonitrile beads, containing the amidoximated polyacrylonitrile, were prepared for adsorption of uranium. The synthesized amidoximated polyacrylonitrile chelating beads were evaluated, for their ability to adsorb uranium from aqueous solution, at different temperatures and pH values. The kinetic measurement showed that about 120 min of equilibration time was enough, to remove saturation amount of uranium from the solution. The pseudo first‐order and pseudo second‐order equations were used to analyze the kinetic data, and the rate constants were determined. The equilibrium adsorption data were examined by the Langmuir, Freundlich, and Temkin isotherms. The data showed a better fit to the Langmuir isotherm. The loaded uranium could also be leached out from the beads, by treating with dilute acids. The uranium uptake capacity of the polymeric beads was found to be 3.5 mg/g of the swollen beads. Reusability of the beads was also established by multiple adsorption–desorption experiments. The pore volume and the surface area of the dried beads, measured by BET method, were found to be 1.93 cc/g and 320 m2/g, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Comparative study of homogeneous solvents for the esterification crosslinking of cellulose with 1,2,3,4‐butanetetracarboxylic dianhydride and water absorbency of the reaction products
Authors: Kono Hiroyuki , Fujita Sayaka , Oeda Ikuo
Published: April 2012

Superabsorbent hydrogels were prepared via esterification crosslinking of cellulose with 1,2,3,4‐butanetetracarboxylic dianhydride (BTCA) in three solvent systems: lithium chloride (LiCl)/N‐methyl‐2‐pyrrolidinone (NMP), LiCl/N,N‐dimethylacetamide (DMAc), and tetrabutylammonium fluoride/dimethyl sulfoxide (TBAF/DMSO). The absorbency of the hydrogels was strongly dependent on the BTCA feed to cellulose ratio as well as the nature of the solvent system used. The rate of cellulose esterification was enhanced in TBAF/DMSO relative to the other systems, and the highest water absorbency of the hydrogels (987 g g−1 polymer) was also achieved using this system. The hydrogels obtained in the TBAF/DMSO system had a similar degree of both crosslinking and grafting, indicating that both reactions were promoted to the same extent in this solvent, whereas crosslinking was preferentially enhanced over grafting in the LiCl/NMP and LiCl/DMAc systems. The difference in the composition of the hydrogels was attributed to the difference in the electronegativity of the fluoride and chloride anions in these solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of copolymerizing fluorine‐bearing monomers on the relationship among internal structure, gas permeability, and transparency in copolymer networks composed of methacrylates and siloxane macromers
Authors: Yokota Mitsuru , Ajiro Hiroharu , Akashi Mitsuru
Published: April 2012

To clarify the effect of the type of acrylic monomer and the molecular weight (Mn) of polydimethylsiloxane (PDMS) on the relationship among the internal structure, oxygen permeability coefficient [P(O2)] and transparency, crosslinked copolymers were prepared with two different acrylic monomers : methyl methacrylate (MMA) and trifluoroethyl methacrylate (TFEMA). PDMS macromers with Mn of 1700, 3300, 4700, and 7800 g/mol were used. DSC measurements suggested that all constituent phases were insoluble with each other. The Mn of PDMS affected both the light transmittance and P(O2). The relationship between the Mn and P(O2) over the low Mn range (1700 and 3300 g/mol), and the calculated PDMS domain size ratio, were found to support the [Mn]2/3 rule into the crosslinked copolymer. Furthermore, a 3300 g/mol Mn copolymer became transparent when the amount of PDMS was greater than PMMA. In addition, copolymerization with TFEMA drastically affected those properties, and this effect was much greater than the effect of the PDMS Mn. To clarify the mechanism of P(O2) improvement induced by TFEMA copolymerization, calculations on the relationship among the P(O2), PDMS volume fraction, and morphology model were performed, and some properties such as solubility parameters should play important roles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Triazine‐containing benzoxazine and its high‐performance polymer
Authors: Wang Dengxia , Li Bin , Zhang Yaoheng , Lu Zaijun
Published: April 2012

A new synthetic route was designed to significantly increase the content of triazine structure in benzoxazine resin. 2,4,6‐Tri(4‐hydroxylphenyl)‐13,5‐s‐triazine (TP) was synthesized by cyclotrimerization of 4‐cyanolphenol and then benzoxazine monomer‐containing triazine [2,4,6‐tri(3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazin‐6‐yl)‐1,3,5‐s‐triazine (BZ‐ta)] was synthesized via Mannich reaction from TP. Finally, the cross‐linked polymer P(BZ‐ta) was produced by thermal polymerization of BZ‐ta. BZ‐ta was characterized by nuclear magnetic resonance spectroscopy (NMR), fourier transform infrared spectroscopy (FTIR), mass spectrum, elemental analysis, and viscosity measurement. Curing behavior of BZ‐ta was studied by differential scanning calorimetry, FTIR, and gel permeation chromatography. The structure and properties of P(BZ‐ta) were investigated by powder X‐ray diffraction, dynamic mechanical analysis, and thermogravimetric analysis. The results showed that the P(BZ‐ta) had high glass temperature (Tg = 322°C), excellent thermal oxidation stability (5 and 10% weight loss temperatures in air up to 403 and 453°C, respectively), high char yield (64%, 800°C in nitrogen), and high flame‐retardance (limiting oxygen index, 39.7). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Physical properties and antimicrobial activity of chilled meat pads containing sodium carboxymethyl cellulose
Authors: Wang Shishuai , Kuang Xuan , Li Bin , Wu Xiaofang , Huang Ting
Published: April 2012

An improved chilled meat pad consisting of nonwoven fabric containing essential oils or active powders, coated by a sodium carboxymethylcellulose (CMCNa) layer was prepared successfully. In the formation of CMCNa film, effects of four acids and pH were examined to obtain optimal results in terms of water, saline, and simulative blood sorption. Fourier Transform Infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry were used to evaluate the CMCNa film. Also, antimicrobial activities were examined in relation to water loss, aerobic bacterial count, and pH. When the pH value was 4.6 adjusted by citric acid, CMCNa film had the largest absorbent capacity. In the first 6 days, pads with essential oils were superior to pads with powders but inhibiting effect decreased with essential oil releasing. The pad with clove powder gained the best inhibiting effect and could extend the shelf life of chilled meat to 10 days. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation of polystyrene/MMT nanocomposite through in situ RAFT polymerization by new chain transfer agent derived from bisphenol A
Authors: Fallahi Hazhir , Koohmareh Gholam Ali
Published: April 2012

Reversible addition‐fragmentation chain transfer (RAFT) polymerization was performed in the presence of a new RAFT agent based on bisphenol A and modified clays and successfully prepared polystyrene/MMT nanocomposite. The structure of RAFT agent was investigated by Fourier transform infrared spectroscopy (FT‐IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). The polymer had well‐defined molecular weight and narrow polydispersity obtained by gel permeation chromatography (GPC). The morphology of polystyrene/MMT nanocomposite was investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) and was found to be exfoliated. Thermal stability of pure polystyrene and polystyrene/MMT synthesized via RAFT polymerization was also investigated and showed better thermal stability for nanocomposite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Application of melt‐blown technology for the manufacture of temperature‐sensitive nonwoven fabrics composed of polymer blends PP/PCL loaded with multiwall carbon nanotubes
Authors: Krucińska Izabella , Surma Beata , Chrzanowski Michał , Skrzetuska Ewa , Puchalski Michał
Published: April 2012

The main aim of this research was to detail the use of melt‐blown technology to manufacture a temperature‐sensitive nonwoven fabric. The sensor properties of the fabric were achieved by application of the optimal composition of immiscible polymer blends loaded with multiwall carbon nanotubes (MWCNTs). As the sensing phase, a dispersion of MWCNTs in poly(ε‐caprolactone) (PCL) was used. The sensing phase was blended with a matrix made of polypropylene (PP). Three different polymer compositions were subjected to the melt‐blowing process, changing the proportion of the matrix polymer to the dispersed phase to the range of 50–70% and changing the MWCNTs content to be between 1.2 and 2%. The selection of technological parameters was based on the thermal characteristics of the polymers used. Nonwoven fabrics made of these composites were characterized by measuring their electrical properties as a function of external stimuli. In particular, their responses to cycle changing of temperature in a range of 20–80°C were monitored. The 70%PP/28.8%/1.2%MWCNT nonwoven fabrics were observed to show the best sensitivity to changes in temperature between 50 and 60°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Influence of unsaturated acid monomer on the morphology of latex particles in the preparation of hollow latex via the alkali post‐treatment
Authors: Deng Wei , Ji Wenjiao , Jiang Yiming , Kan Chengyou
Published: April 2012

Multistage hydrophilic core/hydrophobic shell latexes containing carboxyl groups were prepared via multistep seeded emulsion copolymerization, and particles with different morphologies were obtained after alkali post‐treatment. Influences of the type and content of unsaturated acid monomer on the polymerization and the particle morphology were investigated based on conductometric titration and TEM observation. Results showed that the hydrophilic core/hydrophobic shell particles could be easily formed using methacrylic acid (MAA) instead of acrylic acid. When MAA was 12.2 wt % in the core latex preparation, only fine pores existed inside the alkali‐treated particles. With MAA increased from 20.0 to 30.0 wt %, the alkali‐treated particle morphology evolved from porous, hollow to collapse structure. When MAA further increased to 40.0 wt %, it was difficult to prepare uniform multistage particles and distinct morphologies including solid, deficient swelling, hollow and collapse structure were coexistent in the alkali‐treated particles. Moreover, the forming mechanism of different morphologies was proposed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanically adaptive cellulose‐poly(acrylic acid) polymeric composites in wet–dry cycles
Authors: Luo Hongsheng , Hu Jinlian , Zhu Yong , Wu Jian‐Yong , Zhang Sheng , Fan Ying , Ye Guangdou
Published: April 2012

Polymeric composites consisting of cellulose and poly(acrylic acid) (PAA) are prepared by coagulation/bulk polymerization method. Scanning electron microscopy and thermal gravimetric analysis are used to investigate the homogeneity and the heat‐induced water loss of the composites, respectively. The water absorbed in the composites has strong hydrogen bonding with the polymer chains, as determined by differential scanning calorimetry. The mechanical and structural properties of the composites vary reversibly when the composites are applied into specifically explored wet–dry cycles, which are comprehensively measured by dynamic mechanic analysis, wide‐angle X‐ray diffraction, and Fourier transform infrared. It is unprecedented to explore the cellulose‐PAA composites as a mechanical adaptive material. The cellulose and the PAA chemically react with each other. Most of the cellulose content remains in amorphous state. Thus, the water molecules can diffuse into the composites, leading to the wet–dry mechanical adaptability of the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The shearing effect on hydrophobically associative water‐soluble polymer and partially hydrolyzed polyacrylamide passing through wellbore simulation device
Authors: Zhang Rui , Ye Zhongbin , Peng Lin , Qin Ni , Shu Zheng , Luo Pingya
Published: April 2012

Hydrolyzed polyacrylamide (HPAM) was the traditional polymer and hydrophobically associative water‐soluble polymer (HAWP) was the new polymer with three‐dimensional network both used to flood to enhance oil recovery. The wellbore area was the most important part before the polymer solution injected into stratum. In this article, the shearing effects of the two polymers were studied by a wellbore simulation device. The viscosities of HPAM and HAWP solutions were both decreased around perforation of wellbore simulation device. Interestingly, viscosity of HAWP recovered from stratum 0.2 m. Until stratum 1.6 m, its viscosity recovered almost 50% of original. The data of intrinsic viscosity showed that the molecular chains of HAWP and HPAM were both degraded without any recovery. The contradiction was further studied by particle size and its microstructure. The mean particle size and particle size distribution data both showed HAWP recovered but HPAM was not. The microstructures of HAWP by atomic force microscopy images further explain the recovery of viscosity. The disassembled molecular chain was self‐assembled into aggregate to newly network by hydrophobes with weaker linking than original solution. While the microstructure of HPAM was thoroughly split up to randomly coil without linking. In addition, the viscoelasticity of HAWP was also recovered to some extent but HPAM was not. All the results proved that HAWP has mobility control ability to displace oil in reservoir even if suffered severely shearing by wellbore. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Stochastic processes in the development of pluripotency in vivo
Authors: Wennekamp Sebastian , Hiiragi Takashi
Published: April 2012

The divergence of the pluripotent inner cell mass and extraembryonic trophectoderm from an apparently homogenous population of cells is a decisive event in mammalian preimplantation development. While three models have been proposed to explain early cellular differentiation in the mouse embryo, the initial cue generating asymmetry within the embryo remains elusive. Recently, unexpected heterogeneity in the expression of crucial transcription factors within the blastocyst has raised the intriguing possibility that a stochastic component is involved in lineage divergence. Unraveling the molecular dynamics and developmental function of the observed heterogeneity awaits further investigations at the single‐cell level using quantitative live‐imaging with appropriate reporter lines. The possible involvement of dynamic heterogeneity in the establishment, maintenance and resolution of pluripotency makes this topic highly relevant not only to developmental biology, but also to stem cell research and regenerative medicine. In this review, we discuss the possible involvement of stochastic processes in lineage divergence and the establishment of pluripotency in vivo, based on recent data from mouse embryology and stem cell research.
Alleviating monoterpene toxicity using a two‐phase extractive fermentation for the bioproduction of jet fuel mixtures in Saccharomyces cerevisiae
Authors: Brennan Timothy C.R. , Turner Christopher D. , Krömer Jens O. , Nielsen Lars K.
Published: April 2012

Monoterpenes are a diverse class of compounds with applications as flavors and fragrances, pharmaceuticals and more recently, jet fuels. Engineering biosynthetic pathways for monoterpene production in microbial hosts has received increasing attention. However, monoterpenes are highly toxic to many microorganisms including Saccharomyces cerevisiae, a widely used industrial biocatalyst. In this work, the minimum inhibitory concentration (MIC) for S. cerevisiae was determined for five monoterpenes: β‐pinene, limonene, myrcene, γ‐terpinene, and terpinolene (1.52, 0.44, 2.12, 0.70, 0.53 mM, respectively). Given the low MIC for all compounds tested, a liquid two‐phase solvent extraction system to alleviate toxicity during fermentation was evaluated. Ten solvents were tested for biocompatibility, monoterpene distribution, phase separation, and price. The solvents dioctyl phthalate, dibutyl phthalate, isopropyl myristate, and farnesene showed greater than 100‐fold increase in the MIC compared to the monoterpenes in a solvent‐free system. In particular, the MIC for limonene in dibutyl phthalate showed a 702‐fold (308 mM, 42.1 g L−1 of limonene) improvement while cell viability was maintained above 90%, demonstrating that extractive fermentation is a suitable tool for the reduction of monoterpene toxicity. Finally, we estimated that a limonane to farnesane ratio of 1:9 has physicochemical properties similar to traditional Jet‐A aviation fuel. Since farnesene is currently produced in S. cerevisiae, its use as a co‐product and extractant for microbial terpene‐based jet fuel production in a two‐phase system offers an attractive bioprocessing option. Biotechnol. Bioeng. 2012; 109: 2513–2522. © 2012 Wiley Periodicals, Inc.
Outcomes following surgery without radiotherapy for rectal cancer (Br J Surg 2012; 99: 137–143)
Authors: Janjua A Z , Moran B J
Published: April 2012

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (http://www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.
Chemoprotective effects of carnosine against genotoxicity induced by cyclophosphamide in mice bone marrow cells
Authors: Naghshvar Farshad , Abianeh Shahrzad Mohseni , Ahmadashrafi Saeb , Hosseinimehr Seyed Jalal
Published: April 2012

The protective effects of carnosine as a natural dipeptide were investigated in mouse bone marrow cells against genotoxicity induced by cyclophosphamide. Mice were injected with solutions of carnosine at three different doses (10, 50 and 100 mg kg–1 bw) for five consecutive days. On the fifth day of treatment, mice were injected cyclophosphamide and killed after 24 h. The frequency of micronuclei in polychromatic erythrocytes and the ratio of polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte [PCE/(PCE + NCE)] were evaluated by May‐Grunwald/Giemsa staining. Histopathology of bone marrow was examined in mice treated with cyclophosphamide and carnosine. Carnosine significantly reduced micronucleated polychromatic erythrocytes (MnPCEs) induced by cyclophosphamide at all three doses. Carnosine at dose of 100 mg kg–1 bw reduced MnPCEs 3.76‐fold and completely normalized the PCE/(PCE + NCE) ratio. Administration of carnosine inhibited bone marrow toxicity induced by cyclophosphamide. It appeared that carnosine with protective activity reduced the oxidative stress and genotoxicity induced by cyclophosphamide in bone marrow cells of mice. Copyright © 2012 John Wiley & Sons, Ltd.
Assignment of Relative Configuration of Desoxypropionates by 1H NMR Spectroscopy: Method Development, Proof of Principle by Asymmetric Total Synthesis of Xylarinic Acid A and Applications
Authors: Schmidt Yvonne , Lehr Konrad , Colas Lucie , Breit Bernhard
Published: April 2012

The determination of the relative configuration of 1,3‐dimethyl‐substituted alkyl chains is possible by interpretation of 1H NMR shift differences. Additionally, assignments are feasible in a variety of deuterated solvents, because the corresponding shift differences are not significantly influenced by the solvent. The trends for Δδ values depending on functional groups adjacent to the stereogenic centers are shown. Based on a thorough comparison with literature data, the relative configuration of natural products can be predicted. For this purpose, we derived an empirical rule for the ranges in which Δδ values usually occur. Furthermore, we were able to proof the validity of our method by the successful prediction of the relative configuration for the polyketide natural product xylarinic acid A, which was confirmed by the asymmetric total synthesis of its enantiomer. Based on the proposed simple analysis of published 1H NMR data and the determination of the relevant chemical‐shift differences, we predicted the relative configurations of several previously unassigned natural products.