bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of biodegradable polylactide/poly(butylene carbonate) blend
Authors: Wang Xuemei , Zhuang Yugang , Dong Lisong 
Published: April 2012

AbstractPolylactide (PLA) was melt blended with poly(butylene carbonate) (PBC) in an effort to improve the toughness of the PLA without compromising its biodegradability and biocompatibility. The miscibility, morphology, thermal behavior, and mechanical properties of the blends were investigated. The blend was an immiscible two‐phase system with PBC uniformly dispersed within the PLA matrix. Because of the interfacial function, the incorporation of PBC accelerated the crystallization rate of PLA. By the incorporation of PBC, a polylatide‐based material with high stiffness and toughness was achieved. Even at 10% of PBC, high elongation at break of 139% was obtained, while the tensile strength remained as high as 50.7 MPa. The Pukanszky model gave credit to modest interfacial adhesion between PLA and PBC although PLA/PBC is an immscible blend. The plastic deformation, occurring via debonding process, is an important energy‐dissipation process and leads to a toughened, biodegradable polymer blend. The important point is that the toughening mechanism requires only modest level of adhesion between particles and the polymer. The molecular mobility is a crucial factor for yield stress and plastic flow. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Study of biodegradation evolution during composting of polyethylene–starch blends using scanning electron microscopy
Authors: Vieyra H. , Aguilar‐Méndez M. A. , San Martín‐Martínez E. 
Published: April 2012

AbstractThe end product of low‐density polyethylene–starch was manufactured by injection molding process. Four starch concentrations (10, 25, 40, and 50%) were used for blend preparations, which were injected into the mold of a 250 mL commercial cup. A control sample of neat polyethylene (PE) was also included. Square coupons (4 cm × 4 cm) of each blend were buried in the middle of a 50 cm pile of compost. Samples were recovered, washed, dried, and weighed after 25, 50, 75, 100, and 125 days beneath the compost. Scanning electron microscopy (SEM) analysis was performed on the samples to track the biodegradability evolution. A SEM scandium analyzer was used to measure the size and number of pores and the eroded area. Weight loss measurements were conducted to validate the SEM observations. Total biodegradation time was determined by mathematical analysis and graphical extrapolation. SEM analysis revealed the formation of pores, cavities, discontinuities, and cracks resulting from the time beneath the compost. Pore measurements revealed that the specimen composed of 40% starch and submerged for 125 days experienced up to 25% eroded area. Pure PE remained practically unchanged for the 125‐day period. Fourier transform infrared spectroscopy studies also demonstrated the biodegradation of PE in PE–starch blends. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synergistic inhibition of human glioma cell line by temozolomide and PAMAM‐mediated miR‐21i
Authors: Qian Xiao‐Min , Shi Zhen‐Dong , Ren Yu , Liu Chao‐Yong , Ji Ya‐Ru , Long Li‐Xia , Pu Peiyu , Sheng Jing , Yuan Xu‐Bo , Kang Chun‐Sheng 
Published: April 2012

AbstractTemozolomide (TMZ) is a promising chemotherapeutic agent for treating glioblastomas. However, resistance develops quickly and with a high frequency. Efforts to overcome chemoresistance are, therefore, critically needed. In present study, a poly(amidoamine; PAMAM) dendrimer was used as a vector to deliver microRNA‐21 inhibitor (miR‐21i) into U87 cells and the chemosensitivity of the combination effect of miR‐21i and TMZ for glioma therapy was investigated. Flow cytometry analysis showed the uptake efficiency of microRNA‐21 inhibitor after complexation with PAMAM. Real‐time PCR and in situ hybridization indicated that, compared with TMZ or miR‐21i treated cells, cells simultaneously treated with miR‐21i and TMZ showed a remarkable decrease in the microRNA‐21 (miR‐21) level. The transfection of miR‐21i enhanced the chemosensitivity by significantly decreasing the IC50 value of TMZ to glioma cells. Knockdown of miR‐21 promoted the cells' apoptosis, and at the same time, inhibited cell invasion. In conclusion, the combination treatment of glioma cells with TMZ and miR‐21i could yield a synergistic effect in inhibition of human glioma cell line. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
How does a polymerized compounding affect the nucleation effect of a sorbitol derivative nucleating agent in isotactic polypropylene melt crystallization?
Authors: Yi Qing‐Feng , Wen Xiao‐Jing , Niu Hui , Dong Jin‐Yong 
Published: April 2012

AbstractIn this article, we investigate the effect of a new polymerized compounding method on the nucleation behavior of a sorbitol derivative nucleating agent for isotactic polypropylene (iPP). This method uses a sorbitol derivative nucleating agent, for example, 1,3: 2,4‐dimethylbenzylidene sorbitol (DMBS), which displays itself as aggregated fibrillar crystals, as a support for C2‐symmetric ansa‐metallocenes best represented by rac‐Me2Si[2‐Me‐4‐Naph‐Ind]2ZrCl2. Activating this DMBS‐supported metallocene catalyst with methylaluminoxane, a following in situ propylene polymerization results in the formation of iPP/DMBS composition polymers having controllable DMBS concentrations (by virtue of polymerization productivity control), with the DMBS dispersion driven by catalyst fragmentation. Three iPP/DMBS composition polymers having DMBS concentrations of 0.22, 031, and 0.52 wt % were prepared by this means, which, along with their analog melt‐mixed counterparts, were subjected to melt crystallization kinetics and crystal morphology studies using differential scanning calorimetry, polarized optical microscopy, and UV–vis spectroscopy. With systematically higher nucleation efficiencies and lower crystallization activation energies, the polymerized iPP/DMBS composition polymers exhibited generally stronger DMBS nucleation effects when compared with their melt‐mixed counterparts. Such a benefit was accounted for by a more homogeneous dispersion and better wettability by iPP matrix of DMBS that led to the formation of more nucleation sites and faster crystallization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Free radical polymerization of butyl acrylate in monodispersed droplets: Comparison between two heating strategies
Authors: Zhendong Liu , Yangcheng Lu , Bodong Yang , Guangsheng Luo 
Published: April 2012

AbstractMonodispersed droplets could be easily generated in coaxial microdevice, and a reaction based upon these discrete droplets is an attractive approach thanks to isolated reaction units, efficient mixing, and precise residence time control. In this work, free radical polymerization of butyl acrylate was conducted in monodispersed droplets of several hundred microns. Two different heating methodologies, microwave heating and conventional heating with oil bath were adopted to initiate polymerization, respectively. The polymerization under conventional heating could be regarded as an isothermal process, while the polymerization under microwave heating gradually underwent a temperature increase. So the poly (butyl acrylate) obtained by microwave heating has larger average molecular weight and higher polydispersity index. Meanwhile, the conversion of butyl acrylate was significantly improved by microwave heating compared with conventional heating, even though the reaction temperature under microwave heating might be lower than the temperature of the oil bath. This remarkable enhancement was a direct proof of the nonthermal effect of the microwave field for free radical polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Progression of leprosy neuropathy: a case series study
Authors: Vital Robson T. , Illarramendi Ximena , Nascimento Osvaldo , Hacker Mariana A. , Sarno Euzenir N. , Jardim Marcia R. 
Published: April 2012

AbstractA need still exists to determine the clinical and neurophysiological characteristics of leprosy neuropathy at distinct times of the disease by different methods that measure the various nerve fiber functions. A prospective clinical study was performed with 10 paucibacillary (PB) and 12 multibacillary (MB) patients evaluated at diagnosis and one year after cessation of multidrug therapy (MDT). Peripheral nerve function was assessed clinically and by means of the sympathetic skin response, skin vasomotor reflex, and nerve conduction study (NCS). At diagnosis, 73% of the total 22 patients had nerve function impairment (NFI). Autonomic function (χ2= 5.5, P= 0.019) and NCS (χ2= 7.765, P= 0.01) were significantly more altered in MB than PB patients. At final evaluation, NFI of the MB patients had worsened, especially among the six who had leprosy reaction. As the NFI of PB patients showed improvement, a significant difference between the two groups (χ2= 12.320, P= 0.001) was observed. A high prevalence of neuropathy was observed in newly diagnosed patients. Associating different tests with a thorough clinical neurological evaluation increases detection rates.
Does cerebral lateralization develop? A study using functional transcranial Doppler ultrasound assessing lateralization for language production and visuospatial memory
Authors: Groen Margriet A. , Whitehouse Andrew J. O. , Badcock Nicholas A. , Bishop Dorothy V. M. 
Published: April 2012

AbstractIn the majority of people, language production is lateralized to the left cerebral hemisphere and visuospatial skills to the right. However, questions remain as to when, how, and why humans arrive at this division of labor. In this study, we assessed cerebral lateralization for language production and for visuospatial memory using functional transcranial Doppler ultrasound in a group of 60 typically developing children between the ages of six and 16 years. The typical pattern of left‐lateralized activation for language production and right‐lateralized activation for visuospatial memory was found in the majority of the children (58%). No age‐related change in direction or strength of lateralization was found for language production. In contrast, the strength of lateralization (independent of direction) for visuospatial memory function continued to increase with age. In addition, boys showed a trend for stronger right‐hemisphere lateralization for visuospatial memory than girls, but there was no gender effect on language laterality. We tested whether having language and visuospatial functions in the same hemisphere was associated with poor cognitive performance and found no evidence for this “functional crowding” hypothesis. We did, however, find that children with left‐lateralized language production had higher vocabulary and nonword reading age‐adjusted standard scores than other children, regardless of the laterality of visuospatial memory. Thus, a link between language function and left‐hemisphere lateralization exists, and cannot be explained in terms of maturational change.
Vibrational and electronic circular dichroism monitoring of copper(II) coordination with a chiral ligand
Authors: Wu Tao , Zhang Xiao‐Peng , Li Cheng‐Hui , Bouř Petr , Li Yi‐Zhi , You Xiao‐Zeng 
Published: April 2012

ABSTRACTNovel copper(II) coordination compounds with chiral macrocyclic imine ligands derived from R‐/S‐camphor were asymmetrically synthesized and characterized with the aid of chiroptical spectroscopies. Crystal structures of both enantiomers were determined by single crystal X‐ray diffraction analysis. Circular dichroism (CD) spectra were analyzed using a simplified exciton model as well as quantum chemical computations. The absolute configuration of the copper(II) coordination compounds determined from CD was found consistent with the crystal data. The copper(II) complexes were further investigated by vibrational CD (VCD) measurement combined with density functional theory calculation. The complex formation was evidenced by spectral shifts of the characteristic bands in the CD and VCD spectra. Chirality 24:451–458, 2012. © 2012 Wiley Periodicals, Inc.
Absolute configurations of integracins A, B, and 15′‐dehydroxy‐integracin B
Authors: Liu Hai‐Li , Huang Xiao‐Yin , Li Jia , Xin Guo‐Rong , Guo Yue‐Wei 
Published: April 2012

ABSTRACTIntegracins A (1) and B (2), potent HIV‐1 integrase inhibitors, and 15′‐dehydroxy‐integracin B (3) were isolated for the first time from Chinese mangrove plant Sonneratia hainanensis. Their absolute configurations were determined by the Mosher's method and specific rotation analysis of alcohols (6 and 7) obtained from integracin A in two steps and by chemical correlation. Integracin A (1) also exhibited significant cytotoxicity against the tumor cell lines HepG2 and NCI‐H460 with both 100% inhibitions at 25 µg/ml. Chirality 24:459–462, 2012. © 2012 Wiley Periodicals, Inc.
Chiral recognition of metalaxyl enantiomers by human serum albumin: evidence from molecular modeling and photophysical approach
Authors: Ding Fei , Li Xiu‐Nan , Diao Jian‐Xiong , Sun Ye , Zhang Li , Sun Ying 
Published: April 2012

ABSTRACTMetalaxyl is an acylamine fungicide, belonging to the most widely known member of the amide group. This task is aimed to scrutinize binding region and spatial structural change of principal vector human serum albumin (HSA) complex with (R)‐/(S)‐metalaxyl by exploiting molecular modeling, steady‐state and time‐resolved fluorescence, and circular dichroism (CD) approaches. According to molecular modeling, (R)‐metalaxyl is situated within subdomains IIA and IIIA and the affinity of site I with (R)‐metalaxyl is greater than site II, whereas (S)‐metalaxyl is only located at subdomain IIA and the affinity of (S)‐metalaxyl with site I is superior compared with that with (R)‐metalaxyl. This coincides with the competitive ligand binding, guanidine hydrochloride‐induced unfolding of protein, and hydrophobic 8‐anilino‐1‐naphthalenesulfonic acid experiments; the acting forces between (R)‐/(S)‐metalaxyl and HSA are hydrophobic, π–π interactions, and hydrogen bonds, as derived from molecular modeling. Fluorescence emission manifested that the complex of (R)‐/(S)‐metalaxyl to HSA is the formation of adduct with an affinity of 104 M−1, which corroborates the time‐resolved fluorescence that the static type was operated. Furthermore, the changes of far‐UV CD spectra evidence the polypeptide chain of HSA partially unfolded after conjugation with (R)‐/(S)‐metalaxyl. Through this work, we envisage that it can offer central clues on the biodistribution, absorption, and bioaccumulation of (R)‐/(S)‐metalaxyl. Chirality 24:471–480, 2012. © 2012 Wiley Periodicals, Inc.
Chiral separation of cathinone derivatives used as recreational drugs by HPLC‐UV using a CHIRALPAK® AS‐H column as stationary phase
Authors: Mohr Stefan , Taschwer Magdalena , Schmid Martin G. 
Published: April 2012

ABSTRACTCathinone derivatives gained high popularity on the recreational drugs market during the past 10 years. All these compounds are chiral, and the pharmacological potency of the enantiomers of these stimulants is supposed to differ. The goal of this research was to develop a reliable and easy‐to‐perform high‐performance liquid chromatography ultraviolet method for the chiral separation of a set of 24 cathinone derivatives. A commercially available CHIRALPAK® AS‐H column consisting of amylose tris [(S)‐α‐methylbenzylcarbamate] coated on 5‐µm silica gel was found to be suitable to resolve a majority of the tested compounds. High‐performance liquid chromatography measurements were performed in normal phase mode under isocratic conditions with a mobile phase consisting of hexane, isopropanol, and triethylamine at a flowrate of 1 ml/min. The ratio between hexane and isopropanol was optimized by means of three model substances. Under final conditions with a mobile phase of hexane, isopropanol, and triethylamine (97:3:0.1), 19 out of 24 compounds were successfully resolved into their enantiomers and detected at a wavelength of 254 nm. A correlation between the substituents of the nitrogen atom and the separation results are shown. Furthermore, enantiomer separation results of four cathinone derivatives were compared with the results of their amphetamine analogs. Chirality 24:486–492, 2012. © 2012 Wiley Periodicals, Inc.
Tracking chiral polychlorinated biphenyl sources near a hazardous waste incinerator: Fresh emissions or weathered revolatilization?
Authors: Asher Brian J. , Ross Matthew S. , Wong Charles S. 
Published: April 2012

Abstract
The Swan Hills Treatment Centre (SHTC), located in central Alberta, is the primary facility in Canada for incinerating polychlorinated biphenyls (PCBs). Past studies have shown significant contamination by PCBs and other pollutants of the immediate surrounding region. However, it is unclear whether the major source of contamination to the region's atmosphere is historical release incidents or long-term emissions. To answer this question, concentrations of PCBs and enantiomer fractions of several PCB congeners were determined in soil and air, via polyurethane foam passive samplers, over several seasons between 2005 and 2008. Concentrations in both media were highest for samples collected closest to the SHTC, demonstrating a concentration profile typical of a point source. Enantiomer analysis revealed racemic profiles in air for all congeners, while soil was significantly nonracemic for PCB 95, indicating significant microbial degradation of this congener. However, the primary source of this congener, and likely others, in the surrounding atmosphere is recent and continual releases from the SHTC, rather than the release of weathered PCBs previously deposited to local soils. In addition, enantiomer compositions for PCBs 95 and 149 yielded minimum biotransformation half-lives of 25 and 97 years, respectively, suggesting an expected gradual decline in the region's PCB load once fresh inputs cease. Environ. Toxicol. Chem. 2012; 31: 1453–1460. © 2012 SETAC
Environmental and human exposure to soil chlorinated and brominated polycyclic aromatic hydrocarbons in an urbanized region
Authors: Ni Hong-Gang , Zeng Eddy Y. 
Published: April 2012

Abstract
Nine chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/BrPAHs) and five parent polycyclic aromatic hydrocarbons (PAHs) were measured in urban surface soil and fly ash samples collected from Shenzhen, south China in winter 2010. The concentrations of total Cl/BrPAHs and PAHs in soil ranged from below the reporting limit to 142 ng/g and from 4.34 to 158 µg/g, respectively, and in fly ash they ranged from 17.7 to 19.5 ng/g and 26.1 to 28.3 µg/g, respectively. Concentrations of Cl/BrPAHs and parent PAHs were not significantly correlated with each other in soil or in fly ash, suggesting that Cl/BrPAHs were formed mainly by mechanisms other than direct halogenation of parent PAHs. Estimated mass inventories of 2-BrFlu varied from 68.1 kg in commercial land to 669 kg in countryside land, the highest among all Cl/BrPAHs. Loss fluxes via soil erosion accounted for only small proportions of total soil mass inventories of Cl/BrPAHs. Average daily human intake via soil ingestion decreased with increasing age, with 2-BrFlu as the main contributor. Children of 0 to 8 years old were the most sensitive subgroup (13.7 pg/kg body wt/d for total Cl/BrPAHs), and females were more sensitive than males in the same age group. The mean dioxin-like toxic equivalency quotient (TEQ) concentration of total Cl/BrPAHs (0.008 ng-TEQ/g) was lower in soil than in fly ash (0.06 ng-TEQ/g). Conversely, the mean TEQ concentration of total parent PAHs (2.23 ng-TEQ/g) was higher in soil than in fly ash. Environ. Toxicol. Chem. 2012; 31: 1494–1500. © 2012 SETAC
Phototoxicity of TiO2 nanoparticles under solar radiation to two aquatic species: Daphnia magna and Japanese medaka
Authors: Ma Hongbo , Brennan Amanda , Diamond Stephen A. 
Published: April 2012

Abstract
One target of development and application of TiO2 nanoparticles (nano-TiO2) is photochemical degradation of contaminants and photo-killing of microbes and fouling organisms. However, few ecotoxicological studies have focused on this aspect of nano-TiO2, specifically whether this photoreactivity might significantly increase hazard and risk of the materials in the natural environment. In the present study, we evaluated acute phototoxicity of nano-TiO2 under simulated solar radiation (SSR) to two aquatic species–Daphnia magna and Japanese medaka, using 48-h and 96-h assays, respectively. A thorough characterization of the exposure system was performed by measuring particle agglomeration and TiO2 concentration in suspension in a time-course manner. Sedimentation and loss of bulk concentration of nano-TiO2 particles occurred at all concentrations above 2 mg/L and was more significant as concentration increased. Phototoxicity of nano-TiO2 under SSR was enhanced by two to four orders of magnitude as compared to toxicity under ambient laboratory light, with a 48-h median lethal concentration (LC50) of 29.8 µg/L in D. magna and a 96-h LC50 of 2.2 mg/L in medaka. Our results also indicate that these effects are dependent on simultaneous exposure of the organisms to nanoparticles and SSR. This dramatic increase in toxicity of nano-TiO2 at environmentally realistic levels of SSR indicates the need to incorporate this mode of action into risk assessment for nano-TiO2 and other photoreactive nanomaterials. Environ. Toxicol. Chem. 2012; 31: 1621–1629. © 2012 SETAC
Serum insulin‐like, growth factor binding protein‐related protein 1 (IGFBP‐rP1) and endometrial cancer risk in Chinese women
Authors: Zhan Yan , Wang Jiamin , Ma Yu , Liu Zhiwei , Xu Haiming , Lu Shiming , Lu Bingjian 
Published: April 2012

AbstractHyperinsulinemia and the metabolic syndrome confer increased risks of endometrial carcinoma. The roles of insulin, and, insulin‐like growth factor‐binding proteins (IGFBPs) in the etiology of endometrial carcinoma, remain unclear. We recruited 206 patients with endometrial carcinoma and 350 healthy women to a case–control study of fasting insulin and IGFBP‐related protein 1 (IGFBP‐rP1) in a Chinese tertiary centre. Patients with endometrial carcinoma had higher insulin concentrations (14.8 ± 16.7 vs. 8.1 ± 9.4 μU/mL; p < 0.001) and lower IGFBP‐rP1 levels (17.5 ± 17.2 vs. 22.4 ± 22.8 μg/L; p = 0.018) than controls. High insulin and IGFBP‐rP1 levels were both positively and negatively associated with endometrial cancer (odds ratio for the highest tertile versus the lowest tertile: insulin: 4.11; 95% CI = 2.61–6.47; IGFBP‐rP1: 0.38; 95% CI = 0.24–0.60). Logistic regression analysis confirmed the associations between endometrial carcinoma and fasting insulin or IGFBP‐rP1 after adjustments for age, BMI, serum glucose, cholesterol, triglycerides and high‐density lipoprotein cholesterol (odds ratio for the highest tertile versus the lowest tertile: insulin: 2.13; 95% CI = 1.30–3.49; IGFBP‐rP1: 0.57; 95% CI = 0.34–0.94). Hyperinsulinemia and high IGFBP‐rP1 levels confer altered risks for endometrial carcinoma.