查找使用阿拉丁产品的科研文献

alan j. k. sanders: historical dictionary of mongolia. (asian/oceanian historical dictionaries, 42.) lxxiii, 419 pp. lanham and oxford: the scarecrow press, 2003. £40.

george lane

Chinas Unlimited: Making the Imaginaries of China and Chineseness. By Gregory B. Lee. Honolulu: University of Hawai'i Press, 2003. xi, 121 pp. $45.00 (cloth).

Kathleen Erwin

Regulation on dual-interface of core–shell dispersed phases and mechanical properties of PP blends by rotary evaporation-assisted melt grafted EPDM-g-MAH

Biwei Qiu,Pengfei Qi,Zhongjian Qian,Wenhang Fang,Hua Zou,Xiying Huang

In this study, a series of maleic anhydride-grafted ethylene–propylene–diene rubbers (EPDM-g-MAHs) with different grafting degrees were prepared via the rotary evaporation-assisted melt grafting, which could achieve higher grafting rate and smaller gel content than the traditional melt grafting under the same conditions. Morphological observation, thermal analysis, and rheological measurements confirmed that the interfacial compatibility of the core–shell dispersed phases was enhanced by increasing the composition ratio of EPDM-g-MAH/EPDM or the grafting degree of the prepared EPDM-g-MAHs in the polypropylene (PP) blends. A remarkable improvement in toughness and a little loss in strength and modulus were obtained in the PP blends by regulating the dual interfaces of the core–shell dispersed phases. A new insight into the toughening mechanism of core–shell particles was presented in this work. The balance between toughness and strength could be attributed to the strong dual interfacial interaction of the core–shell dispersed phases, thereby effectively transferring stress. In addition to the conventionally internal cavitation in the rubber phase and the shear yielding of the PP matrix triggered by stress-concentrated dispersed phases, expanded stress field, elongated core phases, and increased cavitation that occurred at dual interfaces by debonding were regarded to contribute to the toughening effect.

A highly hydrophilic cation exchange nonwoven with a further modifiable epoxy group prepared by radiation-induced graft polymerization

Xiao-han Pan,Jian-hua Zu

Novel cation exchange nonwoven PP-g-SSS/GMA containing epoxy and sulfonic groups was successfully prepared via radiation-induced simultaneous grafting polymerization by attaching glycidyl methacrylate (GMA) and styrene sulfonic sodium (SSS) monomers onto nonwoven polypropylene (PP). The ion exchange capacity of the obtained PP-g-SSS/GMA reached more than 1.5 mmol g−1 and the content of the epoxy groups with potential modifiable properties was above 3 mmol g−1. The relative content of the two functional groups could be adjusted via changing the initial monomer concentration ratio. Scanning electron microscope (SEM) images showed that the polymer surface was fully covered with grafts after modification and those amorphous grafts diluted the crystallinity of the matrix, as revealed via differential scanning calorimetry (DSC). Attenuated total reflection spectroscopy (ATR) confirmed the successful grafting of GMA and SSS onto PP nonwovens. Water contact angle measurements showed that the contact angle decreased from 100.94° for the PP matrix to 0° for PP-g-SSS/GMA with a 56% degree of grafting, indicating the outstanding hydrophilicity of PP-g-SSS/GMA upon the introduction of SSS. Besides this, the epoxy groups on PP-g-SSS/GMA could be further modified via reacting them with chemical compounds with selective adsorption groups. Ag(I) adsorption tests proved that PP-g-SSS/GMA@EDA obtained via the ethanediamine (EDA) modification of epoxy groups on PP-g-SSS/GMA shows excellent selectivity towards Ag(I), and the hydrophilicity brought about by sulfonic groups also ensured a fast adsorption rate. The novel cation exchange nonwoven PP-g-SSS/GMA fabric has potential applications in water treatment, as its strong hydrophilicity could speed up the diffusion rates of adsorbed ions, and further functionalization of the epoxy groups could enable it to selectively adsorb ions in aqueous solutions.

Janus fibre/sponge composite combined with IOPNs promotes haemostasis and efficient reconstruction in oral guided bone regeneration

Hanbang Chen,Jia Yan,Shuying Hu,Shangwen Sun,Fang Zhou,Jun Liu,Shijia Tang,Qiao Zhou,Haonan Ding,Feimin Zhang,Ning Gu

Placing a barrier membrane between an alveolar bone wound and gingival soft tissue is a common and effective method to prevent fibroblast invasion and promote new bone formation. However, the combined use of a barrier membrane with bone-forming substitutes remains a challenge for dentists during surgery. Thus, a Janus fibre/sponge composite combining iron oxide nanoparticles (IONPs, γ-Fe 2 O 3 ) was fabricated to prevent epithelial invasion and promote alveolar reconstruction. In the scaffold, a poly (lactic-co-glycolic acid)/polycaprolactone (PP) electrospun layer was covalently bound with a chitosan sponge containing γ-Fe 2 O 3 by polydopamine. The resilient chitosan sponge can easily adhere to the wound surface and encompass haemostatic capability by swelling and forming blood clots to block bleeding. The introduction of IONPs promoted the osteogenesis of rBMSCs, as shown by ALP analysis and cytokine assay. The PP layer maintained its structure integrity and prevented epithelial cells from invading into blood clots or fibroblasts from penetrating through the critical pore size. Assessment with a rat model having one-sided calvarial bone injury further confirmed the effectiveness of Janus scaffolds in facilitating the bone regeneration in the postoperative areas.

Co-microencapsulation of biomass-based char source and melamine polyphosphate and investigation for their synergistic action in flame-retarding polypropylene

Zaihang Zheng,Chenchen Liao,Yurou Xia,Yuhang Liu,Boya Dai,Anbo Li

In this article, co-microencapsulation technology was utilized for decorating the surface of dialdehyde starch (DAS) and melamine polyphosphate (MPP) via one-step process. The aim for this design was to improve the dispersion for DAS and MPP in polypropylene (PP) and employ DAS as sustainable char-forming agent, which lied in enhancing the flame retardancy of PP. In view of chemical composition , morphology and surface wettability , the changes for DAS and MPP after modification were confirmed by energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and water contact angle (WCA) tests, respectively. Most of all, the results for flame retardant tests demonstrated limiting oxygen index (LOI) value and vertical burning tests (UL-94) rating of PP/30 ph M[M&D] were 28.2% and V-1. Along with the synergistic effect, the homogeneous dispersion of DAS and MPP in PP after co-microencapsulation modification was also one of main reasons for the increased flame retardant properties. Except that, the chemical interaction between DAS and MPP in producing the char layer was also certified by TGA curves. After systematic analysis on char residue, the possible intumescent flame retardant mechanism was primarily proposed.

Standard of Living: The Measure of the Middle Class in Modern America. By Marina Moskowitz. Baltimore: The Johns Hopkins University Press, 2004. xii + 300 pp. Index, notes, bibliography, illustrations. Cloth, $45.00. ISBN: 0-801-87947-7.

Tracey Deutsch

Powder X-ray diffraction detection on a paper-based platform

Liangfei Ouyang,Qian Liu,Chaoping Xu,Changgui Liu,Heng Liang

We developed paper-based powder X-ray diffraction (PP-XRD) to implement phase identification and/or crystal structure determination on paper-based platforms. These aims are not possible with other paper-based detectors, such as Raman spectroscopy and mass spectrometry. PP-XRD overcomes these limitations. Here we reported the simple and low-cost in situ PP-XRD protocol for phase identifications of inorganic and organic materials. We demonstrated that sample amounts of lead nitrate on paper substrate can be reduced into 1/30 of conventional ones by using the standard glass substrate at the same signal-to-noise ratio (S/N) of the X-ray diffraction (XRD) pattern. The paper-based method was comparable in sample quantity and intensity with zero background holder method, even though single crystal Si(100) substrate as zero background holder was used for the specimen preparation of CTAB (C 19 H 42 BrN). More importantly, paper substrates helped reduce preferred orientation that was generally present in routine powder XRD. Also, combined with paper chromatography , overlap peaks were eliminated in the XRD detection patterns of lead nitrate and cobalt nitrate hexahydrate. This new PP-XRD protocol may accelerate the process to identify phase or determine the molecular structures of new materials using trace sample directly. It also includes a hyphenated technique of powder XRD with a simple paper-based microfluidic separation of chemical solutions .

Sensitive quantification of mevalonate pathway intermediates and prediction of relative novel analogs by chemical derivatization-based LC-MS/MS

Meiyu Gao,Jiarui Sun,Qinwen Xiao,Yuanyuan Zhai,Yuan Tian,Zunjian Zhang,Fengguo Xu,Pei Zhang

The mevalonate (MVA) pathway plays a crucial role in the occurrence and progression of various diseases, such as osteoporosis, breast cancer, and lung cancer, etc. However, determining all the MVA pathway intermediates is still challenging due to their high polarity, low concentration, chelation effect with metal compartments, and poor mass spectrometric response. In this study, we established a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method coupled with N 2 , N 2 , N 4 , N 4 -tetramethyl-6-(4-(piperazin-1-ylsulfonyl) phenyl)-1,3,5-triazine-2,4-diamine (Tmt-PP) labeling for the simultaneous analysis of all MVA intermediates in biospecimens. Chemical derivatization significantly improved the chromatographic retention, peak shape, and detection sensitivity of the analytes. Moreover, we employed a method named mass spectrum calculation to achieve the absolute quantification of the isomers, i.e., isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). The established method was fully qualified and applied to explore the difference of these metabolites in cisplatin-resistant non-small cell lung cancer (NSCLC) cells. Additionally, several MVA intermediate analogs, including isopentenyl monophosphate or dimethylallyl monophosphate (IMP/DMAMP), geranyl monophosphate (GMP), 5-triphosphomevalonate (MTP), and isopentenyl triphosphate or dimethylallyl triphosphate (ITP/DMATP), were identified for the first time using a knowledge-driven prediction strategy. We further explored the tissue distribution of these novel metabolites. Overall, this work developed a sensitive quantification method for all MVA intermediates, which will enhance our understanding of the role of this pathway in various health and disease conditions. The novel metabolites we discovered warrant further investigations into their biosynthesis and biological functions.