Controlled radical polymerization of N‐vinylcaprolactam (NVCL) via reversible addition‐fragmentation chain transfer (RAFT) polymerization or macromolecular design via the interchange of xanthate (MADIX) was described, employing 2‐diphenylthiocarbamoylsulfanyl‐2‐methyl‐propionic acid (CTA1), ((O‐ethylxanthyl)methyl)benzene (CTA2) and (1‐(O‐ethylxanthyl)ethyl)benzene (CTA3) as chain transfer agents (CTA). It was found that all the CTAs led to controlled radical polymerization of NVCL, with the molecular weight increased along with the conversion of monomer and a relatively narrow molecular weight distribution could be obtained, as determined with matrix‐assisted laser desorption and ionization time‐of‐flight (MALDI‐TOF) and gel permeation chromatography (GPC), the polydispersity indices, as determined by MALDI‐TOF, were typically on the order of 1.24, but the polymerization did not proceed in a strictly living manner. The chain transfer ability of these CTAs was in the following order: CTA1 ≈ CTA2 < CTA3. MALTI‐TOF measurement showed that the major population of polymer retained the chain‐end functional group, but minor population deactivated by radical coupling. In preparation of the block copolymer of NVCL and vinyl acetate (VAc) by sequential polymerization, the sequence of monomer addition was important. Using VAc as the first monomer could lead to a block copolymer presenting a unimodal GPC trace and a narrow PDI index, and if NVCL was used as the first monomer, the polymerization was less well controlled. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3756–3765, 2008

Cytospolides A-E (1-5), five new nonanolides with an unprecedented 15-carbon skeleton with the unique chemical feature of a C-2 methyl group, were isolated from the endophytic fungus Cytospora sp. The structures were elucidated by spectroscopic analysis, chemical interconversion, and single-crystal XRD. The solution and solid state conformers were compared by experimental methods (X-ray, NMR) and solvent and gas phase DFT calculations. The absolute configurations were assigned by time dependent (TD)-DFT calculations of CD spectra, including solution and solid state CD/

Colon cancer (CC) is the third common neoplasm worldwide, and it is still a big challenge for exploring new effective medicine for treating CC. Natural product promoting human health has become a hot topic and attracted many researchers recently. Pectin, a complex polysaccharide in plant cell wall, mainly consists of four major types of polysaccharides: homogalacturonan, xylogalacturonan, rhamnogalacturonan I and II, all of which can be degraded into various pectin oligosaccharides (POS) and may provide abundant resource for exploring potential anticancer drugs. POS have been regarded as a novel class of potential functional food with multiple health-promoting properties. POS have antibacterial activities against some aggressive and recurrent bacterial infection and exert beneficial immunomodulation for controlling CC risk. However, the molecular functional role of POS in the prevention of CC risk and progression remains doubtful. The review focuses on antioxidant and anti-inflammatory roles of POS for promoting human health by regulating some potential oxidative and inflammation-activated pathways, such as ATP-activated protein kinase (AMPK), nuclear factor erythroid-2-related factor-2 (Nrf2), and nuclear factor-κB (NF-κB) pathways. The activation of these signaling pathways increases the antioxidant and antiinflammatory activities, which will result in the apoptosis of CC cells or in the prevention of CC risk and progression. Thus, POS may inhibit CC development by affecting antioxidant and antiinflammatory signaling pathways AMPK, Nrf2, and NF-κB. However, POS also can activate signal transduction and transcriptional activator 1 and 3 signaling pathway, which will reduce antioxidant and anti-inflammatory properties and promote CC progression. Specific structural and structurally modified POS may be associated with their functions and should be deeply explored in the future. The present review paper lacks the important information for the linkage between the specific structure of POS and its function. To further explore the effects of prebiotic potential of POS and their derivatives on human immunomodulation in the prevention of CC, the specific POS with a certain degree of polymerization or purified polymers are highly demanded to be performed in clinical practice.

Four new cyclopeptides, phakellistatins 15-18 (2-5), together with five known cyclopeptides, phakellistatin 13 (1), hymenistatin 1, and hymenamides G, H, and J, were isolated from the South China Sea sponge Phakellia fusca. Their structures were elucidated by HR-ESIMS, NMR, and MALDI-TOF/TOF sequence analysis. The absolute configurations of the amino acid residues of 2-5 were assigned to be l by enantioselective HPLC analysis.

A highly effective (1)H NMR method for determining the absolute configurations of various chiral α-hydroxyl acids and their derivatives has been developed with the use of bisthioureas (R)-CSA 1 and (S)-CSA 1 as chiral solvating agents in the presence of DABCO, giving distinguishable proton signals with up to 0.66 ppm chemical shift nonequivalence. Computational modeling studies were performed with Gaussian09 to reveal the chiral recognition mechanism.

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Purpose – The purpose of this study is to examine and compare the different roles and expectations of the school librarians as information literacy (IL) instructors between Hong Kong, Japan, Shanghai, South Korea, and Taipei. School librarians are not merely managers of the school libraries nowadays; they are also expected to serve as administrators, teaching consultants, information specialists and IL teachers, etc. Unfortunately, in many countries, especially in Asia, there has always been a lack of understanding on the parts of the classroom teachers and school administration about their role as IL specialists in the public school system. Design/methodology/approach – The school librarians in Hong Kong, Japan, Shanghai, South Korea and Taipei were invited to take part in a questionnaire survey. A total number of 466 self-completed questionnaires were collected from all 5 regions. Findings – The results indicated that the school librarians in both Taipei and South Korea outperformed the other regions, in terms of the scope and extent of duties and responsibilities these school librarians undertook as IL skills instructors. The staffing and organizational structures amongst the school libraries in Taipei also tended to be far more affluent and “departmentalized” in comparison to the other four regions. Results also indicated that the amount of IL instructions carried out by the school librarians were directly proportional to the frequencies of collaborations the school librarians carried out with other subject teachers as well as the extent the librarians themselves could contribute to the curriculum as both information consultants and curriculum facilitators. Finally, the amount and level of reference duties performed by these school librarians for supporting the teaching of other subject teachers was another factor contributing to the overall success of IL instructions programmes being carried out. Originality/value – The complex interactions of global trend and local responses in education system cannot easily be understood without the use of comparative studies (Arnove and Torres, 1999). The value of comparative studies lies in its potentials in highlighting the strengths and deficiencies of the education systems being examined and thereby identifying valuable features of both foreign and local systems, as well as exposing defects for necessary improvements. Nevertheless, there has been a lack of cross-regional comparative research on IL programmes carried out via school libraries in East Asia. This study aims to provide a cross-analysis of empirical data collected in five different regions in East Asia for examining the issues of the role of the school librarians as IL skills specialists, by looking at their relationships with other colleagues as well as their role as curriculum facilitator within the school community as a whole.