bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of chemical constituents in extracts and rat plasma from Fructus Aurantii by UPLC‐PDA‐Q‐TOF/MS
Authors: Ma Chaoyi , Gao Wenyuan , Gao Ying , Man Shuli , Huang Luqi , Liu Changxiao 
Published: January 2011

AbstractIntroduction – Fructus Aurantii, as a component of several compound formulae, shows many bioactivities. As is well known, the constituents of traditional Chinese medicines are very complex and multiple constituents are responsible for the therapeutic effect. However, the concrete compounds are difficult to confirm. Therefore, studies on the constituents absorbed into serum and their metabolites are necessary.Objective – To search for the active constituents in Fructus Aurantii.Methodology – An ultra‐performance liquid chromatography–photodiode array detector–quadrupole time‐of‐flight mass spectrometry (UPLC‐PDA‐Q‐TOF/MS) method was established to analyse the aqueous extract in Fructus Aurantii and the constituents absorbed into blood. Compound identification was made by matching the empirical molecular formula with those of the reported compounds and UV spectra, and further elucidated by lower energy CID mass spectra.Results – Twelve flavonoidO‐glycosides were detected, and nine compounds were tentatively identified as polymethoxylated flavones. Six parent compounds were identified and four metabolites were observed in rat plasma, two of which were identified as naringenin glucuronide and hesperetin glucuronide, respectively.Conclusion – The approach developed has proved useful in the study of the active constituents in traditional Chinese medicines. Copyright © 2011 John Wiley & Sons, Ltd.
Phytochemical fingerprinting of vegetable Brassica oleracea and Brassica napus by simultaneous identification of glucosinolates and phenolics
Authors: Velasco Pablo , Francisco Marta , Moreno Diego A. , Ferreres Federico , García‐Viguera Cristina , Cartea María Elena 
Published: January 2011

AbstractIntroduction – Brassica vegetables have been related to the prevention of cancer and degenerative diseases, owing to their glucosinolate and phenolic content.Objective – Identification of glucosinolates, flavonoids and hydroxycinnamic acids in representative varieties of kale, cabbage and leaf rape.Methodology – One local variety of each crop was evaluated in this study using a multi‐purpose chromatographic method that simultaneously separates glucosinolates and phenolics. Chromatograms were recorded at 330 nm for flavonoid glycosides and acylated derivatives and 227 nm for glucosinolates.Results – Eight glucosinolates were identified in kale and cabbage, which exhibited the same glucosinolate profile, and 11 glucosinolates were identified in leaf rape. Furthermore, 20 flavonoids and 10 hydroxycinnamic acids were detected in kale and cabbage, while 17 flavonoids and eight hydroxycinnamic acids were found in leaf rape.Conclusions – This study has provided a deeper and comprehensive identification of health‐promoting compounds in kale, cabbage and leaf rape, thus showing that they are a good source of glucosinolates and phenolic antioxidants. Copyright © 2011 John Wiley & Sons, Ltd.
Isolation of four high‐purity dammarane saponins from extract of Panax notoginseng by centrifugal partition chromatography coupled with evaporative light scattering detection in one operation
Authors: Wang Jing , Liu Chun‐ming , Li Li , Bai He‐long 
Published: January 2011

AbstractIntroduction – Centrifugal partition chromatography (CPC), as a continuous liquid–liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of weak‐chromophoric saponins from a highly valued and important traditional Chinese herbal medicine, Panax notoginseng.Objective – To separate and isolate high‐purity saponins from extract of Panax notoginseng using CPC‐ELSD with a simple and low toxicity solvent system.Methodology – Samples were preparaed by extracting the root material with acetone, treated with n‐butanol and then freeze‐dried. CPC‐ELSD was applied in the separation and detection of notoginsenoside and ginsenosides from extract of Panax notoginseng using a solvent system composed of ethyl acetate–n‐butanol–water (1:1:2, v/v/v). The saponins were analysed and identified by their retention time with high‐performance liquid chromatography (HPLC) coupled with ELSD, as well as electrospray ionisation tandem mass spectrometry (ESI‐MSn
) in the negative and positive ion modes with the authentic standards.Results – A total of 9.6 mg of notoginsenoside R1, 67.8 mg of ginsenoside Rg1, 2.3 mg of Re and 286.5 mg of Rb1 were purified from 487.2 mg of n‐butanol extract of P. notoginseng. The purities of obtained saponins in a single run were assessed to be over 98% by HPLC‐ELSD.Conclusion – CPC‐ELSD was proved to be a very fast and efficient tool for separation of high‐purity dammarane saponins. Copyright © 2011 John Wiley & Sons, Ltd.
Long‐term use of zopiclone, zolpidem and zaleplon among Danish elderly and the association with sociodemographic factors and use of other drugs
Authors: Andersen Ane Birgitte Telén , Frydenberg Morten 
Published: January 2011

AbstractPurposeTo estimate the degree of long‐term use of zopiclone, zolpidem and zaleplon among Danes aged 65 and older and the association with sociodemographic factors and use of other drugs.MethodsDanish register‐based study of 5000 men and 5000 women aged 65 or older on 1 January 2004. Information on sociodemographic factors and drug redemptions were collected for 2003, with follow‐up of zopiclone, zolpidem and zaleplon redemptions in 2004. Long‐term use was defined as redemptions corresponding to a continuous daily use for more than 4 weeks (based on ½ DDD). The association between long‐term use and sociodemographics and drug use was estimated by logistic regression.ResultsTen per cent of all men and 16% of all women had a long‐term use for minimum 4 weeks corresponding to 94% of the male and 93% of the female users. Four per cent of the men and 6% of the women had redeemed more than ½ DDD per day in 2004. Long‐term use was associated with: Being a woman, high age, widowed or divorced, high education and high gross income. Long‐term use was also associated with use of other drugs, the association with ATC group N being the strongest. Restricting the analyses to individuals who had minimum one zopiclone, zolpidem or zaleplon redemption gave similar results.ConclusionThe results indicate that the guidance for length of use is not followed. Long‐term use of zopiclone, zolpidem and zaleplon is associated with sociodemographic factors and use of other drugs, particularly from ATC group N. Copyright © 2011 John Wiley & Sons, Ltd.
Fire retardant properties of intumescent polypropylene composites filled with calcium carbonate
Authors: Isitman Nihat Ali , Dogan Mehmet , Bayramli Erdal , Kaynak Cevdet 
Published: January 2011

AbstractThis study was aimed to investigate the influence of calcium carbonate (CaCO3), a widely used filler, on the fire retardancy of intumescent polypropylene composites. Two intumescent systems based on (1) mixture of ammonium polyphosphate (APP) and pentaerythritol and (2) surface‐modified APP (m‐APP) were examined. In terms of steady heat release rate, total heat evolved, and fire growth index determined by mass loss calorimetry, m‐APP performed markedly superior to APP‐pentaerythritol. The presence of CaCO3 in both intumescent formulations caused significant losses in fire retardant performance assessed by mass loss calorimetry, limiting oxygen index and UL‐94 tests. Peak rates of heat release and mass loss during combustion, and total heat evolved on combustion were increased, whereas time to ignition was decreased. Characterization of fire residues ascribed the mechanism of deterioration in fire retardancy to the formation of porous and nonexpanded crystalline calcium phosphate/CaCO3 residues during combustion rather than the amorphous protective intumescent chars formed in the absence of CaCO3. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis and properties of photosensitive poly(urethane‐acrylate) containing anil groups with application in the chemosensors area
Authors: Buruiana Emil C. , Jitaru Florentina , Hitruc Gabriela , Buruiana Tinca 
Published: January 2011

AbstractSome aspects of the enol‐imine to keto‐enamine photoisomerism and fluorescent behavior of the new monomer with urethane and anil units in its structure, namely, methacryloyloxyethyl‐2‐carbamoyloxy(m‐methyl, o‐hydroxybenziliden)aniline (UAN), were studied comparatively with the corresponding copolymer poly (methacryloyloxyethyl‐2‐carbamoyloxy(m‐methyl, o‐hydroxybenziliden)aniline)‐co‐methyl methacrylate) (COP‐UAN). The structure, thermal properties, and morphology of the anil compounds were investigated by Fourier transform infrared, proton nuclear magnetic resonance, fluorescence spectroscopies, UV spectrophotometry, thermogravimetric analysis, differential scanning calorimetry, and atomic force microscopy. The photochromic behavior of salicylideneanil units was investigated by UV/laser irradiation, and an inspection of their photophysical properties suggested that such structures could function as fluorescent chemosensors for some transition metals, a fluorescence quenching in the presence of different metal cations (Fe3+, Fe2+, Cu2+, and Ni2+) being evidenced. The direct observation of an enhancement in the fluorescence emission caused of the presence of Zn2+ (solution) or Fe2+, Cu2+, and Zn2+ (thin film) would be rather suitable for the production of turn‐on fluorescent chemosensors. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Mechanical properties and deformation behaviors of acrylonitrile‐butadiene‐styrene under Izod impact test and uniaxial tension at various strain rates
Authors: Xu X.Y. , Xu X.F. 
Published: January 2011

AbstractTwo polybutadiene‐graft‐acrylonitrile‐styrene copolymer (PBD‐g‐SAN) impact modifiers with different rubber particle size were synthesized by seeded emulsion polymerization. Acrylonitrile‐butadiene‐styrene (ABS) blends with a constant rubber concentration of 15 wt% were prepared by blending those impact modifiers and SAN resin. The major focus was the mechanical properties and deformation mechanisms of ABS blends under Izod impact test and uniaxial tension at various strain rates from 2.564 × 10−4 S−1 upto 1.282 × 10−1 S−1. By the combination of transmission electron microscope and scanning electron microscope, it was concluded that crazes and cavitation coexisted in ABS blends. The deformation mechanisms of ABS blend containing large rubber particles was rubber particles cavitation and shear yielding in the matrix including crazes, and they do not change with the strain rate. Different from ABS blend with large rubber particles, deformation mechanism of ABS with small rubber particles under tensile condition was only involved in shear yielding in the matrix and no crazes were formed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Processing and characterization of recycled poly(ethylene terephthalate) blends with chain extenders, thermoplastic elastomer, and/or poly(butylene adipate‐co‐terephthalate)
Authors: Srithep Yottha , Javadi Alireza , Pilla Srikanth , Turng Lih‐Sheng , Gong Shaoqin , Clemons Craig , Peng Jun 
Published: January 2011

AbstractPoly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Because thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding elastomeric modifiers, chain extenders (CE), and poly(butylene adipate‐co‐terephthalate), PBAT, as a toughener to RPET on its moldability and mechanical property were investigated. Melt blending of RPET with CE, thermoplastic elastomer (TPE), and/or PBAT was performed in a thermokinetic mixer (K‐mixer). The blended materials were then injection molded to produce tensile specimens. Various techniques were used to study the mechanical properties, rheological properties, compatibility, and crystallization behavior of the RPET blends. By melt blending with proper additives, recycled PET regained its moldability, thereby enabling the recycling of RPET. Furthermore, the addition of CE greatly enhanced the mechanical properties of RPET. While the RPET and TPE blends also showed improved mechanical properties, the improvement was less significant and the blends were often immiscible due to the difference in polarities between RPET and TPE. Finally, it was found that the mechanical properties of RPET blends depended on the prior thermal history of the material and could be improved with an extra annealing step that increased the degree of crystallinity. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Synthesis of main‐chain poly(carbazole)s via CuAAC
Authors: Chen Zheng , Dreyer Daniel R. , Wu Zong‐quan , Wiggins Kelly M. , Jiang Zhenhua , Bielawski Christopher W. 
Published: January 2011

AbstractThe synthesis and characterization of a novel family of main‐chain carbazole‐containing polymers using copper‐catalyzed azide‐alkyne cycloaddition chemistry is reported. The reactions were performed under mild conditions using readily available copper catalysts and ligands, which afforded polymeric products with Mws up to 18 kDa. Using a range of techniques, the polymers were found to exhibit a glass transition temperature (Tg) of 85 °C, high thermal stability (Td = 274 °C), and high photoluminescent quantum efficiency (ϕf = 0.29; λem = 448 nm), which underscore their potential for use in organic light‐emitting diodes or other emissive devices, particularly where efficient blue emission is of value. The approach described offers practical advantages over other synthetic methods used to prepare main‐chain carbazole‐containing polymers, especially with regard to the lack of need for rigorously inert conditions and the absence of byproducts generated during the polymerization reaction. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Influence of electronic effects from bridging groups on synthetic reaction and thermally activated polymerization of bisphenol‐based benzoxazines
Authors: Wang Xiaoying , Chen Feng , Gu Yi 
Published: January 2011

AbstractSix bis‐benzoxazines based on bisphenols with different bridging groups, C(CH3)2, CH2, O, CO, SO2, and single bond, were synthesized in toluene. The influence of electronic effects from bridging groups on ring‐forming reaction and thermal ring‐opening polymerization were relatively discussed in detail. Their structures were characterized by high‐performance liquid chromatography, Fourier transform infrared, 1H NMR, differential scanning calorimetry, and elementary analysis. The quantum chemistry parameters of the bisphenols and bis‐benzoxazines were calculated by molecular simulation. The results indicated that the electron‐withdrawing groups inhibited the synthetic reaction by decreasing the charge density of α‐Cs of bisphenols and increasing energy barriers of the synthetic reactions. However, the electron‐withdrawing groups promoted the thermally activated polymerization, which resulted from their activation energy and curing temperature decrease by increasing the bond length and lowering the bond energy of CO on oxazine rings. Besides, because of stronger electron‐withdrawing sulfone group, there were more arylamine methylene Mannich bridge structure in the polybenzoxazine. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of poly(tert‐butyl methacrylate)‐graft‐poly(dimethylsiloxane) graft copolymers via reversible addition‐fragmentation chain transfer polymerization
Authors: Li Jiawei , Yi Lingmin , Lin Heming , Hou Ruigang 
Published: January 2011

AbstractWell‐defined poly(tert‐butyl methacrylate)‐graft‐poly (dimethylsiloxane) (PtBuMA‐g‐PDMS) graft copolymers were synthesized via reversible addition‐fragmentation chain transfer (RAFT) copolymerization of methacryloyl‐terminated poly (dimethylsiloxane) (PDMS‐MA) with tert‐butyl methacrylate (tBuMA) in ethyl acetate, using 2,2′‐azobis(isobutyronitrile) (AIBN) as the initiator and 2‐cyanoprop‐2‐yl dithiobenzoate as the RAFT agent. The RAFT statistical copolymerization of PDMS‐MA with tBuMA is shown to be azeotropic and the obtained PtBuMA‐g‐PDMS graft copolymers have homogeneously distributed branches because of the similar reactivity of monomers (rtBuMA ≈ rPDMS‐MA ≈ 1). By the RAFT block copolymerization of PDMS‐MA with tBuMA, moreover, narrow molecular weight distribution (Mw/Mn < 1.3) PtBuMA‐g‐PDMS graft copolymers with gradient or blocky branch spacing were synthesized. The graft copolymers exhibit the glass transitions corresponding to the PDMS and PtBuMA phase, respectively. However, the arrangement of monomer units in copolymer chains and the length of PtBuMA moieties have important effects on the thermal behavior of PtBuMA‐g‐PDMS graft copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Narrow disperse polymers using amine functionalized dithiobenzoate RAFT agent and easy removal of thiocarbonyl end group from the resultant polymers
Authors: Jana Satyasankar , Parthiban Anbanandam , Chai Christina L.L. 
Published: January 2011

AbstractA novel amine functionalized RAFT agent, 2‐cyanoprop‐2‐yl(4‐N,N‐dimethylaminophenyl) dithiobenzoate has been synthesized and used to control the polymerization of vinyl monomers. This dithiobenzoate RAFT agent, although air sensitive, controlled the polymerization of MMA and St very well in an inert atmosphere and the polymerization results obtained were marginally better than using the most popular 2‐cyanoprop‐2‐yl dithiobenzoate RAFT agent. The living nature of these polymerizations was confirmed by kinetics study and chain extension reactions to yield narrow disperse di‐block copolymers. Most importantly, use of this novel RAFT agent simplified the removal procedure of the color causing end thiocarbonyl group from the RAFT derived polymers and thereby leading to polymers with improved appearance. The removal of end group from the polymer was confirmed by 1H NMR and UV‐vis spectroscopic techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Relationship of knowledge of psychosocial issues about cancer with psychic distress and adjustment among breast cancer clinic attendees in a Nigerian teaching hospital
Authors: Ohaeri Beatrice M. , Ofi Abosede B. , Campbell Oladapo B. 
Published: January 2011

AbstractObjectives: The diagnosis of breast cancer prompts emotional reactions, which predispose to psychosocial problems and poor adjustment. Assessment of the psychosocial issues could help articulation of specific interventions. There is paucity of data on psychosocial issues in breast cancer from Nigeria. We assessed knowledge of psychosocial issues about breast cancer and its association with psychic distress and adjustment among women attending a Nigerian teaching hospital. Methods: We used a descriptive survey design to assess 63 consecutive clinic attendees (mean age: 49.9, SD: 10.5) who met the eligibility criteria. Data were obtained using the following: a 15‐item self‐report validated psychosocial needs questionnaire, General Health Questionnaire (GHQ‐12) and 10‐item adjustment scale. Results: Majority (63.4%) indicated they did not know much about the nature of breast cancer. The greatest area of worry was related to fear of death (81.0%). Knowledge about management of breast cancer was significantly inversely correlated with psychic distress (p<0.03). High psychic distress was significantly related to psychosocial concerns (p<0.01), and inversely correlated with adjustment (p<0.001).The most important predictor of psychic distress and adjustment was their fear about how people reacted to them. Conclusions: The findings support previous reports indicating that psychosocial concerns are associated with psychic distress and poor adjustment in breast cancer. Accordingly, a regular psycho‐oncology service should include counseling on improved prognosis in cancer with early patronage of modern treatments, to allay fear of death; while public health education on social stigma should address fear of negative reactions from people. Copyright © 2011 John Wiley & Sons, Ltd.
Protein disulfide isomerase isomerizes non‐native disulfide bonds in human proinsulin independent of its peptide‐binding activity
Authors: Winter Jeannette , Gleiter Stefan , Klappa Peter , Lilie Hauke 
Published: January 2011

AbstractProtein disulfide isomerase (PDI) supports proinsulin folding as chaperone and isomerase. Here, we focus on how the two PDI functions influence individual steps in the complex folding process of proinsulin. We generated a PDI mutant (PDI‐aba′c) where the b′ domain was partially deleted, thus abolishing peptide binding but maintaining a PDI‐like redox potential. PDI‐aba′c catalyzes the folding of human proinsulin by increasing the rate of formation and the final yield of native proinsulin. Importantly, PDI‐aba′c isomerizes non‐native disulfide bonds in completely oxidized folding intermediates, thereby accelerating the formation of native disulfide bonds. We conclude that peptide binding to PDI is not essential for disulfide isomerization in fully oxidized proinsulin folding intermediates.
A secretory system for bacterial production of high‐profile protein targets
Authors: Kotzsch Alexander , Vernet Erik , Hammarström Martin , Berthelsen Jens , Weigelt Johan , Gräslund Susanne , Sundström Michael 
Published: January 2011

AbstractEscherichia coli represents a robust, inexpensive expression host for the production of recombinant proteins. However, one major limitation is that certain protein classes do not express well in a biologically relevant form using standard expression approaches in the cytoplasm of E. coli. To improve the usefulness of the E. coli expression platform we have investigated combinations of promoters and selected N‐terminal fusion tags for the extracellular expression of human target proteins. A comparative study was conducted on 24 target proteins fused to outer membrane protein A (OmpA), outer membrane protein F (OmpF) and osmotically inducible protein Y (OsmY). Based on the results of this initial study, we carried out an extended expression screen employing the OsmY fusion and multiple constructs of a more diverse set of human proteins. Using this high‐throughput compatible system, we clearly demonstrate that secreted biomedically relevant human proteins can be efficiently retrieved and purified from the growth medium.
Crystal structure of the Nogo‐receptor‐2
Authors: Semavina Mariya , Saha Nayanendu , Kolev Momchil V. , Goldgur Yehuda , Giger Roman J. , Himanen Juha P. , Nikolov Dimitar B. 
Published: January 2011

AbstractThe inhibition of axon regeneration upon mechanical injury is dependent on interactions between Nogo receptors (NgRs) and their myelin‐derived ligands. NgRs are composed of a leucine‐rich repeat (LRR) region, thought to be structurally similar among the different isoforms of the receptor, and a divergent “stalk” region. It has been shown by others that the LRR and stalk regions of NgR1 and NgR2 have distinct roles in conferring binding affinity to the myelin associated glycoprotein (MAG) in vivo. Here, we show that purified recombinant full length NgR1 and NgR2 maintain significantly higher binding affinity for purified MAG as compared to the isolated LRR region of either NgR1 or NgR2. We also present the crystal structure of the LRR and part of the stalk regions of NgR2 and compare it to the previously reported NgR1 structure with respect to the distinct signaling properties of the two receptor isoforms.