bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of hydrophobic polymer particles by radical polymerization and subsequent modification into magnetically doped particles
Authors: Ahmad Hasan , Abu‐Waesmin Mohammad , Rahman Mohammad Mahbubor , Jalil Miah Mohammad Abdul , Tauer Klaus 
Published: April 2012

AbstractThe application potential of hydrophobic polymer is numerous. Lauryl methacrylate (LMA) having long alkyl chain is a commercially available hydrophobic monomer. In this investigation, poly‐LMA (PLMA) latex particles were prepared by suspension polymerization in aqueous media using 2,2′‐azobis(isobutyronitrile) (AIBN) in presence of poly(vinyl alcohol) (PVA) as steric stabilizer. The preparation kinetics was studied in detail in terms of percentage yield and particle size variation. Low glass transition temperature (∼ −65°C) associated with high flexibility did not allow electron micrographic observation though 1H‐NMR and particle size measurement confirmed the formation of PLMA latex. To improve the glass transition temperature, aqueous emulsion copolymerization of LMA with methyl methacrylate (MMA) was carried out. The solubility of LMA was improved by adding ethanol to the aqueous phase. Two types of polymeric stabilizers, PVA and poly(vinyl pyrrolidone) (PVP) were used to stabilize the colloidal particles. The nature of the stabilizer affected both morphology and final rate of polymerization. The hydrophobic P(LMA‐MMA) copolymer particles were subsequently modified by nanosized magnetic (Fe3O4) particles by two different methods. The in situ formation of Fe3O4 particles in presence of P(LMA‐MMA) was found to be suitable for the preparation of magnetic latex particles. Scanning electron microscope (SEM), FTIR, transmission electron microscope (TEM), X‐ray diffraction (XRD) and energy‐dispersive X‐ray spectroscopy (EDX) were used for the characterization of magnetically doped particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Morphology and rheological properties of high density polyethylene/fluorothermoplastics blends
Authors: Siengchin S. , Abraham Thomas N. 
Published: April 2012

AbstractThe polyolefin blends of high‐density polyethylene (HDPE) with two types of fluorothermoplastics (THV500 and THV220); were prepared by melt compounding technique. The morphology, crystallization, and the viscoelastic measurements of the blends were carried out. The dispersion of THVs was studied by scanning electron microscopy (SEM) technique, and discussed. The crystallization characteristics of the blend were studied using Differential scanning calorimetry (DSC). The oscillatory shear measurement was employed for determining the rheological properties of the prepared blends. There is a significant difference in the rheological behavior of the HDPE blends with THV500 and THV220. The dynamic linear viscoelastic behavior (storage modulus and viscosity) of HDPE/THV500 was found to be higher than that of HDPE/THV220 blend. This was attributed to the molecular weight and particle size distribution of THVs. However, the molecular weight effect of THVs on the crystallization behavior of the blend is marginal. The master curves of the storage and loss modulus vs. frequency were constructed by applying the time–temperature–superposition (TTS) principle. It was established that the parsimonious and modified Cox‐Merz models are fairly applicable to the storage modulus and viscosity results. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structural, mechanical, and biocompatibility analyses of a novel dental restorative nanocomposite
Authors: Khan A. S. , Wong F. S. L. , McKay I. J. , Whiley R. A. , Rehman I. U. 
Published: April 2012

AbstractStructure and biocompatibility are key parameters that determine the usefulness of dental materials for clinical use. Novel polyurethane (PU) nanocomposite material was prepared by chemically binding nanohydroxyapatite (nHA) to the diisocyanate component of the PU backbone by solvent‐polymerization. nHA was incorporated into PU by the stepwise addition of monomeric units of the PU. The PU/nHA composite was analyzed by 13C Nuclear magnetic resonance (structural) and X‐ray diffraction (phase analysis). The tensile strength and elastic modulus was evaluated for mechanical properties. These analyses revealed linkage between the hard‐ and soft‐segments are urethane linkage and showed high mechanical properties with increase in content of nHA. To assess biocompatibility osteoblast cells were seeded on to the material and allowed to adhere and proliferate. Osteoblast‐like cell growth and proliferation was assessed by MTS assay. It was found that cells adhered and proliferated on these novel substrates. To test bacterial adhesion discs of composite with and without nHA were incubated with standardized suspensions of oral bacterium Streptococcus sanguinis strain NCTC 7863. PU composites with nHA exhibited biocompatibility with respect to mammalian cell growth and showed significantly reduced bacterial adhesion as compared to PU alone. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Investigation on the reaction between polyhexamethylene guanidine hydrochloride oligomer and glycidyl methacrylate
Authors: Wei Dafu , Zhou Rihui , Guan Yong , Zheng Anna , Zhang Youwei 
Published: April 2012

AbstractPolyhexamethylene guanidine hydrochloride (PHMG) oligomer is attracting increasing attention for its highly efficient biocidal activity and nontoxicity. To make it bearing carbon‐to‐carbon double bonds and enlarge its application in production of antimicrobial materials via copolymerization, PHMG oligomer was modified via reaction with glycidyl methacrylate (GMA). The influence of reaction parameters on the conversion rate of GMA was investigated using ultraviolet absorption spectroscopy. The structures of PHMG oligomer before and after modification were characterized by Fourier transform infrared spectrometry, Raman spectrometry, nuclear magnetic resonance spectrometry, and electrospray ionization time‐of‐flight mass spectrometry. The results show that carbon‐to‐carbon double bond is successfully introduced into the modified PHMG oligomer. At a feeding molar ratio of GMA to PHMG of 1.0, the conversion rate of GMA reached up to 75% after 60 h of reaction at 60°C in dimethyl sulfoxide. Also, there is an activity difference in the different aminos of PHMG oligomer: the primary amino is ready to react with epoxy of GMA, while the guanidyl amino hardly reacts with GMA due to the p‐π conjugation. Furthermore, the modified PHMG oligomer was used as comonomer to synthesize acrylonitrile copolymer, showing excellent antimicrobial activity against Staphylococcus aureus. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and application of polycarbosilane supported manganese ions as catalyst in mannich reaction
Authors: Mangala Kunniyur , Sreekumar Krishnapillai 
Published: April 2012

AbstractPolycarbosilane (PCS) with highly crosslinked structure and high surface area was synthesized by the polycondensation reaction between trimethoxyvinylsilane and trichloromethylsilane. The reaction was conducted in the presence of sodium metal. Manganese ion was supported on PCS. The immobilization of transition metal ions to polymer support leads to a number of advantages over homogeneous catalyst, viz easy product recovery, increased selectivity, etc. The catalytic activity of PCS supported manganese ion was studied by considering three‐component Mannich reaction. Reaction with diverse sets of aldehydes, amines, and ketones was examined. PCS‐supported manganese ion catalyst has been prepared for the first time and used successfully in Mannich reaction. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of Triptolide on T‐Cell Receptor Beta Variable Gene mRNA Expression in Rats With Collagen‐Induced Arthritis
Authors: Wang Jixi , Wang Aibing , Zeng Heqing , Liu Lantao , Jiang Wenhao , Zhu Yongjie , Xu Yudong 
Published: April 2012

AbstractTriptolide (TP) has been used in the treatment of rheumatoid arthritis (RA), but its mechanism of action is not understood. T‐cell activation and associated release of cytokines appear to be major factors in the pathogenesis of RA. The overexpression of T‐cell receptor (TCR) variable gene (V gene) fragments can cause the activation and infiltration of autoreactive T cells. This study examines the effects of TP on rats with collagen‐induced arthritis (CIA). The levels of interleukin‐10 (IL‐10) in the serum were examined with ELISA. Compared to the CIA group, the levels of IL‐10 were greater in the TP treatment group. Real‐time quantitative polymerase chain reaction confirmed that the expression of TCR V beta (BV) 15 and TCR BV19 was increased in the CIA group, whereas in the TP treatment group, the expression was decreased. In this study, TP was found to enhance IL‐10 levels and decrease the expression levels of TCR BV15 and TCR BV19. These changes might help explain the effectiveness of TP in the treatment of RA. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
The Influence of Maximum Running Speed on Eye Size: A Test of Leuckart's Law in Mammals
Authors: Heard‐Booth Amber N. , Kirk E. Christopher 
Published: April 2012

AbstractVertebrate eye size is influenced by many factors, including body or head size, diet, and activity pattern. Locomotor speed has also been suggested to influence eye size in a relationship known as Leuckart's Law. Leuckart's Law proposes that animals capable of achieving fast locomotor speeds require large eyes to enhance visual acuity and avoid collisions with environmental obstacles. The selective influence of rapid flight has been invoked to explain the relatively large eyes of birds, but Leuckart's Law remains untested in nonavian vertebrates. This study investigates the relationship between eye size and maximum running speed in a diverse sample of mammals. Measures of axial eye diameter, maximum running speed, and body mass were collected from the published literature for 50 species from 10 mammalian orders. This analysis reveals that absolute eye size is significantly positively correlated with maximum running speed in mammals. Moreover, the relationship between eye size and running speed remains significant when the potentially confounding effects of body mass and phylogeny are statistically controlled. The results of this analysis are therefore consistent with the expectations of Leuckart's Law and demonstrate that faster‐moving mammals have larger eyes than their slower‐moving close relatives. Accordingly, we conclude that maximum running speed is one of several key selective factors that have influenced the evolution of eye size in mammals. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Large‐eddy simulation of urban boundary‐layer flows by generating turbulent inflows from mesoscale meteorological simulations
Authors: Nakayama Hiromasa , Takemi Tetsuya , Nagai Haruyasu 
Published: April 2012

AbstractWe propose an approach to generate turbulent flows by using mesoscale meteorological simulations in order to conduct building‐resolving large‐eddy simulations (LESs) of boundary‐layer flows over urban areas under realistic meteorological conditions. The urban surface geometry was explicitly represented in the LES model. This approach was applied for a strong wind event in Tokyo owing to the landfall of a major typhoon whose intensity and track were well reproduced in the meteorological simulation. The observed ranges of wind fluctuations and gust factors and significant decelerations of wind speeds within the urban canopy layer were successfully represented in the LES. Copyright © 2012 Royal Meteorological Society
The impact of the Madden‐Julian oscillation trend on the Antarctic warming during the 1979–2008 austral winter
Authors: Yoo Changhyun , Lee Sukyoung , Feldstein Steven 
Published: April 2012

AbstractAntarctica is one of the regions where the earth's surface is warming most rapidly. The interdecadal warming trend over much of Antarctica during the austral winter is about 1 °C decade−1, which is almost twice that of the global mean. There is increasing observational and modeling evidence that high‐latitude warming is linked to localized heating in the tropics. Here we show that interdecadal changes in the spatial patterns of the extratropical response to various phases of the Madden–Julian oscillation (MJO) explain 10–20% of the interdecadal warming over Antarctica, possibly through the poleward propagation of tropically forced Rossby wave trains. Copyright © 2012 Royal Meteorological Society
Identification of novel antibacterial peptides isolated from a commercially available casein hydrolysate by autofocusing technique
Authors: Elbarbary Hend A. , Abdou Adham M. , Nakamura Yasushi , Park Eun Young , Mohamed Hamdi A. , Sato Kenji 
Published: April 2012

AbstractAutofocusing, as a simple and safe technique, was used to fractionate casein hydrolysate based on the amphoteric nature of its peptides. The antibacterial activity of casein hydrolysate and its autofocusing fractions (A1–10) was examined against Escherichia coli and Bacillus subtilis. The basic fraction A9 exhibited the highest activity with minimum inhibitory concentration (MIC) of 150 μg/mL, whereas casein hydrolysate showed MIC values ranging from 2000 to 8000 μg/mL. The antibacterial peptides in A9 were purified by using a series of size exclusion and reversed phase chromatographies. Three peptides exhibited the most potent antibacterial activity with MIC values ranging from 12.5 to 100 μg/mL. These peptides were generated from αs2‐casein, αs1‐casein, and κ‐casein and identified as K165KISQRYQKFALPQYLKTVYQHQK188, I6KHQGLPQEV15, and T136EAVESTVATL146, respectively. Therefore, the results revealed that casein hydrolysate had potent antibacterial peptides that could be isolated by autofocusing technique. © 2012 International Union of Biochemistry and Molecular Biology, Inc.
Critical appraisal of the ‘wait and see’ approach in rectal cancer for clinical complete responders after chemoradiation
Authors: Glynne-Jones R , Hughes R 
Published: April 2012

Abstract

Background
Some 10–20 per cent of patients with locally advanced rectal cancer achieve a pathological complete response (pCR) at surgery following preoperative chemoradiation (CRT). Some demonstrate a sustained clinical complete response (cCR), defined as absence of clinically detectable residual tumour after CRT, and do not undergo resection. The aim of this review was to evaluate non-operative treatment of rectal cancer after CRT, and the outcome of patients observed without radical surgery.

Methods
A systematic computerized search identified 30 publications (9 series, 650 patients) evaluating a non-operative approach after CRT. Original data were extracted and tabulated, and study quality evaluated. The primary outcome measure was cCR. Secondary outcome measures included locoregional failure rate, disease-free survival and overall survival.

Results
The most recent Habr-Gama series reported a low locoregional failure rate of 4·6 per cent, with 5-year overall and disease-free survival rates of 96 and 72 per cent respectively. These findings were supported by a small prospective Dutch study. However, other retrospective series have described higher recurrence rates. All studies were heterogeneous in staging, inclusion criteria, study design and rigour of follow-up after CRT, which might explain the different outcomes. The definition of cCR was inconsistent, with only partial concordance with pCR. The results suggested that patients who are observed, but subsequently fail to sustain a cCR, may fare worse than those who undergo immediate tumour resection.

Conclusion
The rationale of a ‘wait and see’ policy relies mainly on retrospective observations from a single series. Proof of principle in small low rectal cancers, where clinical assessment is easy, should not be extrapolated uncritically to more advanced cancers where nodal involvement is common. Long-term prospective observational studies with more uniform inclusion criteria are required to evaluate the risk versus benefit.
Diagnosis of postoperative pancreatic fistula
Authors: Facy O , Chalumeau C , Poussier M , Binquet C , Rat P , Ortega-Deballon P 
Published: April 2012

Abstract

Background
Pancreatic fistula (PF) is a major source of morbidity after pancreatectomy. The International Study Group on Pancreatic Fistula (ISGPF) defines postoperative fistula by an amylase concentration in the abdominal drain of more than three times the serum value on day 3 or more after surgery. However, this definition fails to identify some clinical fistulas. This study examined the association between lipase measured in abdominal drainage fluid and PF.

Methods
Amylase and lipase levels in the abdominal drain were measured 3 days after pancreatic resection. Grade B and C fistulas were classified as clinical fistulas, regardless of whether the measured amylase concentration was considered positive or negative. The PF group included patients with a clinical fistula and/or those with positive amylase according to the ISGPF definition.

Results
Sixty-five patients were included. The median level of lipase was higher in patients with positive amylase than in those with negative amylase: 12 176 versus 64 units/l (P &lt; 0·001). The lipase level was 16 500 units/l in patients with a clinical fistula and 224 units/l in those without a clinical fistula (P = 0·001). Patients with a PF had a higher lipase concentration than those without: 7852 versus 64 units/l (P &lt; 0·001). A lipase level higher than 500 units/l yielded a sensitivity of 88 per cent and a specificity of 75 per cent for PF. For clinical fistulas the sensitivity was 93 per cent and specificity 77 per cent when the threshold for lipase was 1000 units/l.

Conclusion
Lipase concentration in the abdominal drain correlated with PF. A threshold of 1000 units/l yielded a high sensitivity and specificity for the diagnosis of clinical PF.
Volunteering to Help Conserve Endangered Species: An Identity Approach to Human–Animal Relationships
Authors: Abell Jackie 
Published: April 2012

ABSTRACTThis study explores identity in providing voluntary help for endangered animal species. Identity is a cornerstone of social psychological explanations of helping behaviour but has not been understood in relation to human–animal relationships. Open‐ended questionnaires were administered to 111 volunteers working in a range of international conservation projects aimed at protecting endangered animals. Participants were asked their reasons for volunteering, choice of project, experiences and expectations. Thematic textual analysis explored common features across the dataset. Themes identified were identifying with animals, humans dominating nature and collective identity with the organization and fellow volunteers. The paper suggests social psychological knowledge about helping behaviour be applied to understand human–animal interactions to offer insight into the conditions under which we will engage with conservational and environmental concerns and provide aid. Social psychology has been slow to apply its knowledge to an examination of human responses to the challenge of loss of biodiversity. To act, humans must identify with those they seek to protect. Copyright © 2012 John Wiley & Sons, Ltd.
A Uniform Sub‐50 nm‐Sized Magnetic/Upconversion Fluorescent Bimodal Imaging Agent Capable of Generating Singlet Oxygen by Using a 980 nm Laser
Authors: Chen Feng , Zhang Shengjian , Bu Wenbo , Chen Yu , Xiao Qingfeng , Liu Jianan , Xing Huaiyong , Zhou Liangping , Peng Weijun , Shi Jianlin 
Published: April 2012

AbstractUpconverting nanoparticles (UCNPs) with fascinating properties hold great potential as nanotransducers for solving the problems that traditional photodynamic therapy (PDT) has been facing. In this report, by using well‐selected bifunctional gadolinium (Gd)‐ion‐doped UCNPs and water‐soluble methylene blue (MB) combined with the water‐in‐oil reverse microemulsion technique, we have succeeded in developing a new kind of UCNP/MB‐based PDT drug, NaYF4:Er/Yb/Gd@SiO2(MB), with a particle diameter less than 50 nm. Great efforts have been made to investigate the drug‐formation mechanism and provide detailed physical and photochemical characterizations and the potential structure optimization of the as‐designed PDT drug. We envision that such a PDT drug will become a potential theranostic nanomedicine for future near‐infrared laser‐triggered photodynamic therapy and simultaneous magnetic/optical bimodal imaging.
Thermal Cleavage of Cyclobutane Rings in Photodimerized Coordination‐Polymeric Sheets
Authors: Chanthapally Anjana , Kole Goutam Kumar , Qian Kang , Tan Geok Kheng , Gao Song , Vittal Jagadese J. 
Published: April 2012

AbstractThree coordination polymers, [Cd2(pvba)2(tbdc)(dmf)2] (1), [Co2(pvba)2(tbdc)(dmf)2(H2O)2] (2), and [Ni2(pvba)2(tbdc)(dmf)2(H2O)2] (3) (H2tbdc=2,3,5,6‐tetrabromobenzenedicarboxylic acid, Hpvba=trans‐2‐(4′‐pyridyl)vinylbenzoic acid), were synthesized by solvothermal methods. The solid‐state structures of compounds 1 and 2 were determined by X‐ray crystallography. In compounds 1 and 2, the bimetallic cores acted as secondary building units that connected the tbdc ligands in one direction and a pair of pvba ligands, which were aligned in a head‐to‐tail parallel manner, in the orthogonal direction to form sheet structures. The CC bonds in these pvba ligand pairs in all three compounds were well‐aligned to undergo quantitative [2+2] cycloaddition reactions in the solid state under UV irradiation, thereby yielding their cyclobutane derivatives. This photochemical reaction appeared to facilitate structural transformations from one 2D structure into another in the solid state. The photoreactive CoII‐ and NiII coordination polymers exhibited a reversible dehydration–rehydration reaction that was accompanied by color changes from pink to purple and green to yellow, respectively, owing to a change in coordination number from six to five. Magnetic studies showed that compound 2 was an antiferromagnet, which displayed a field‐dependent transition with a critical field (Hc) of 40 kOe at 2 K; the antiferromagnetic interaction between the Co2 units was strengthened and weakened by dehydration and UV irradiation, respectively. The cyclobutane ligand in the photodimerized products was cleaved on heating to yield a mixture of trans‐ and cis‐isomers of pvba, as monitored by 1H NMR spectroscopy. The CdII coordination polymer underwent quantitative cleavage of the cyclobutane ring whilst the other two underwent partial cleavage.
A Guest‐Dependent Approach to Retain Permanent Pores in Flexible Metal–Organic Frameworks by Cation Exchange
Authors: Lin Zu‐Jin , Liu Tian‐Fu , Huang Yuan‐Biao , Lü Jian , Cao Rong 
Published: April 2012

AbstractTwo anionic metal–organic frameworks were successfully prepared based on pre‐designed flexible multicarboxylate ligands and indium cations. Owing to the flexibility of the bridging organic linkers, which could not themselves sustain the frameworks, both of the frameworks showed thermal instability and shrinkage after removal of guest solvent molecules. Inspired by bamboo, we used a guest‐dependent approach to tune the permanent porosity of the MOFs. In this approach, several tetraalkyammonium cations of different sizes were introduced into the channels by cation exchange to act as partitions and to support the main frameworks. This approach significantly enhanced the stability of the framework and its permanent porosity. Moreover, the gas‐adsorption properties (such as gate sorption, hysteresis, and selectivity) of the MOFs were also modulated by the judicious choice of guest cations.