bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insight into Pyridinium Chlorochromate Chemistry: Catalytic Oxidation of Tetrahydrofuran Compounds and Synthesis of Umbelactone
Authors: Piccialli Vincenzo , Zaccaria Sabrina , Oliviero Giorgia , D'Errico Stefano , D'Atri Valentina , Borbone Nicola 
Published: June 2012

AbstractThe catalytic system PCC (cat.)/H5IO6 has been used to oxidise mono‐ and polytetrahydrofuran compounds. New oxidative pathways are disclosed. 2,2,5‐Trisubstituted THF rings are converted into dicarbonyl compounds through oxidative cleavage of the C2–C3 bond. Cyclic enol ethers appear to be intermediate species in this process. Oxidation of 2,2,5‐trisubstituted α‐keto‐THF compounds proceeds with the oxidative cleavage of the C2(THF)–C=O bond to give 1,4‐diketones with degraded carbon backbones. Attack of the oxidant on 2,5‐disubstituted THF rings leads to 1,4‐diketones containing intact THF carbon frameworks. Oxidation of complex poly‐THF substrates, containing up to five THF rings, allows access to new poly‐THF compounds through regioselective THF oxidation along the poly‐THF backbones. A mechanistic explanation of the new processes consistent with the reported reactivity of PCC and the isolation of some minor products of the process is provided. The synthesis of racemic umbelactone, an antiviral natural butenolide metabolite, has been carried out by use of the developed chemistry.
Optimal control of linear and nonlinear asymmetric structures by means of passive energy dampers
Authors: Aguirre J. J. , Almazán J. L. , Paul C. J. 
Published: June 2012

SUMMARYAsymmetric structures experience uneven deformation demand among different resisting planes and stories when subjected to earthquake excitation. Damage is focused in some elements jeopardizing structural integrity. These structures are common in professional practice because of architectural and functionality constraints. In this scenario the use of energy dissipation devices (EDD) has arisen as an advisable solution to balance and minimize structural damage. Procedures for the design of linear structures equipped with EDD have been widely proposed in the literature, few of them deal with the optimum spatial distribution of nonlinear systems. This paper evaluates and compares the optimized spatial damper distribution of linear and nonlinear systems. An optimization technique is presented based on control indexes called min–max algorithm. Then, this technique is compared with two simple methodologies: (i) the fully stressed design, which is an analysis‐redesign procedure, and (ii) the simplified sequential search algorithm (SSSA), which is a sequential method. It is pointed out that the SSSA is a fixed step coordinate descent type method. The examples considered show that the SSSA is a discrete approximation of the min–max algorithm, not only for linear but also for nonlinear structures equipped with linear and nonlinear EDD. Furthermore, it is found that the distribution of EDD obtained from a linear analysis is a good approximation of the nonlinear optimal solution. The SSSA is a reliable method that can be applied to achieve drift and torsional balance for design purposes; moreover, it can be implemented with conventional tools available in professional practice. Copyright © 2012 John Wiley & Sons, Ltd.
The Link Between Negative Emotions and Eating Disorder Behaviour in Patients with Anorexia Nervosa
Authors: Espeset Ester M. S. , Gulliksen Kjersti S. , Nordbø Ragnfrid H. S. , Skårderud Finn , Holte Arne 
Published: June 2012

AbstractBackgroundSeveral theoretical models suggest that deficits in emotional regulation are central in the maintenance of anorexia nervosa (AN). Few studies have examined how patients view the relationship between negative affect and anorectic behaviour. We explored how patients with AN manage the aversive emotions sadness, anger, fear and disgust, and how they link these experiences to their eating disorder behaviours.MethodsQualitative data were collected through semi‐structured interviews with 14 women aged 19–39 years diagnosed with AN (DSM‐IV). Interviews were analyzed using Grounded Theory methods.ResultsThe participants tended to inhibit expression of sadness and anger in interpersonal situations and reported high levels of anger towards themselves, self‐disgust and fear of becoming fat. Different emotions were managed by means of specific eating disorder behaviours. Sadness was particularly linked to body dissatisfaction and was managed through restrictive eating and purging. Anger was avoided by means of restrictive eating and purging and released through anorectic self‐control, self‐harm and exercising. Fear was linked to fear of fatness and was managed through restrictive eating, purging and body checking. Participants avoided the feeling of disgust by avoiding food and body focused situations.ConclusionTreatment models of eating disorders highlight the significance of working with emotional acceptance and coping in this patient group. Knowledge about how patients understand the relationships between their negative emotions and their anorectic behaviour may be an important addition to treatment programmes for AN. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.
Addition of dimethyl phosphite to imines bearing the L‐methionine moiety and its surprisingly poor chiral assistance
Authors: Lewkowski Jarosław , Karpowicz Rafał 
Published: June 2012

AbstractThe preparation of methyl 2‐{[(dimethoxyphosphoryl)‐methyl]‐amino}‐4‐methyl‐ sulfanylbutyrates (3a–e) by the addition of dimethyl phosphite to 2‐(methylidenamino)‐4‐methylsulfanylbutyric acid methyl esters (2a–e) is described. The nearly nonexisting diastereoselectivity, which was observed in all cases, is unexpected and astonishing in light of the fact that some other amino acid esters, e.g., leucine, demonstrated very high stereoselectivity in similar reactions. The separation of formed diastereoisomers occurred. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:395–398, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21029
Low‐serum GTA‐446 anti‐inflammatory fatty acid levels as a new risk factor for colon cancer
Authors: Ritchie Shawn A. , Tonita Jon , Alvi Riaz , Lehotay Denis , Elshoni Hoda , Myat Su‐ , McHattie James , Goodenowe Dayan B. 
Published: June 2012

AbstractGastrointestinal tract acid‐446 (GTA‐446) is a long‐chain polyunsaturated fatty acid present in the serum. A reduction of GTA‐446 levels in colorectal cancer (CRC) patients has been reported previously. Our study compared GTA‐446 levels in subjects diagnosed with CRC at the time of colonoscopy to the general population. Serum samples and pathology data were collected from 4,923 representative subjects undergoing colonoscopy and from 964 subjects from the general population. Serum GTA‐446 levels were determined using a triple‐quadrupole tandem mass spectrometry method. A low‐serum GTA‐446 level was based on the bottom tenth percentile of subjects with low risk based on age (40–49 years old) in the general population. Eighty‐six percent of newly diagnosed CRC subjects (87% for stages 0–II and 85% for stages III–IV) showed low‐serum GTA‐446 levels. A significant increase in the CRC incidence rate with age was observed in subjects with low GTA‐446 levels (p = 0.019), but not in subjects with normal levels (p = 0.86). The relative risk of CRC given a low GTA‐446 level was the highest for subjects under age 50 (10.1, 95% confidence interval [C.I.] = 6.4–16.4 in the reference population, and 7.7, 95% C.I. = 4.4–14.1 in the colonoscopy population, both p < 0.0001), and declined with age thereafter. The CRC incidence rate in subjects undergoing colonoscopy with low GTA‐446 levels was over six times higher than for subjects with normal GTA‐446 levels and twice that of subjects with gastrointestinal symptoms. The results show that a low‐serum GTA‐446 level is a significant risk factor for CRC, and a sensitive predictor of early‐stage disease.
Expression profiling shows differential molecular pathways and provides potential new diagnostic biomarkers for colorectal serrated adenocarcinoma
Authors: Conesa‐Zamora Pablo , García‐Solano José , García‐García Francisco , Turpin María del Carmen , Trujillo‐Santos Javier , Torres‐Moreno Daniel , Oviedo‐Ramírez Isabel , Carbonell‐Muñoz Rosa , Muñoz‐Delgado Encarnación , Rodriguez‐Braun Edith , Conesa Ana , Pérez‐Guillermo Miguel 
Published: June 2012

AbstractSerrated adenocarcinoma (SAC) is a recently recognized colorectal cancer (CRC) subtype accounting for 7.5 to 8.7% of CRCs. It has been shown that SAC has a poorer prognosis and has different molecular and immunohistochemical features compared with conventional carcinoma (CC) but, to date, only one previous study has analyzed its mRNA expression profile by microarray. Using a different microarray platform, we have studied the molecular signature of 11 SACs and compared it with that of 15 matched CC with the aim of discerning the functions which characterize SAC biology and validating, at the mRNA and protein level, the most differentially expressed genes which were also tested using a validation set of 70 SACs and 70 CCs to assess their diagnostic and prognostic values. Microarray data showed a higher representation of morphogenesis‐, hypoxia‐, cytoskeleton‐ and vesicle transport‐related functions and also an overexpression of fascin1 (actin‐bundling protein associated with invasion) and the antiapoptotic gene hippocalcin in SAC all of which were validated both by quantitative real‐time PCR (qPCR) and immunohistochemistry. Fascin1 expression was statistically associated with KRAS mutation with 88.6% sensitivity and 85.7% specificity for SAC diagnosis and the positivity of fascin1 or hippocalcin was highly suggestive of SAC diagnosis (sensitivity = 100%). Evaluation of these markers in CRCs showing histological and molecular characteristics of high‐level microsatellite instability (MSI‐H) also helped to distinguish SACs from MSI‐H CRCs. Molecular profiling demonstrates that SAC shows activation of distinct signaling pathways and that immunohistochemical fascin1 and hippocalcin expression can be reliably used for its differentiation from other CRC subtypes.
Establishment and intra‐/inter‐laboratory validation of a standard protocol of reactive oxygen species assay for chemical photosafety evaluation
Authors: Onoue Satomi , Hosoi Kazuhiro , Wakuri Shinobu , Iwase Yumiko , Yamamoto Toshinobu , Matsuoka Naoko , Nakamura Kazuichi , Toda Tsuguto , Takagi Hironori , Osaki Naoto , Matsumoto Yasuhiro , Kawakami Satoru , Seto Yoshiki , Kato Masashi , Yamada Shizuo , Ohno Yasuo , Kojima Hajime 
Published: June 2012

ABSTRACTA reactive oxygen species (ROS) assay was previously developed for photosafety evaluation of pharmaceuticals, and the present multi‐center study aimed to establish and validate a standard protocol for ROS assay. In three participating laboratories, two standards and 42 coded chemicals, including 23 phototoxins and 19 nonphototoxic drugs/chemicals, were assessed by the ROS assay according to the standardized protocol. Most phototoxins tended to generate singlet oxygen and/or superoxide under UV–vis exposure, but nonphototoxic chemicals were less photoreactive. In the ROS assay on quinine (200 µm), a typical phototoxic drug, the intra‐ and inter‐day precisions (coefficient of variation; CV) were found to be 1.5–7.4% and 1.7–9.3%, respectively. The inter‐laboratory CV for quinine averaged 15.4% for singlet oxygen and 17.0% for superoxide. The ROS assay on 42 coded chemicals (200 µm) provided no false negative predictions upon previously defined criteria as compared with the in vitro/in vivo phototoxicity, although several false positives appeared. Outcomes from the validation study were indicative of satisfactory transferability, intra‐ and inter‐laboratory variability, and predictive capacity of the ROS assay. Copyright © 2012 John Wiley & Sons, Ltd.
Cellular responses to electrospun membranes made from blends of PLLGA with PEG and PLLGA‐b‐PEG
Authors: Ma Chi , Pang Di , Xiong Zuochun , Bai Wei , Xiong Chengdong 
Published: June 2012

AbstractControl of cellular responses is crucial for the use of electrospun membranes in biomedical applications, including tissue engineering or biomedical devices. However, it is still unclear whether adhesion and proliferation of fibroblasts is stimulated or inhibited on polyethylene glycol (PEG)‐modified electrospun membranes. In this study, poly(L‐lactide‐co‐glycolide) (PLLGA)–PEG copolymer and pure PEG were blended with PLLGA, and then electrospun onto nonwoven membranes. The effects of blending of PLLGA–PEG or pure PEG on the adsorption of proteins, and further on the adhesion and proliferation of L929 fibroblasts on the electrospun membranes were investigated. Addition of PLLGA–PEG or PEG significantly improved the hydrophilicity of the electrospun membranes. Pure PEG had no obvious effects on the growth of L929 fibroblasts; in contrast, PLLGA–PEG significantly inhibited the adsorption of proteins and the proliferations of the cells on the electrospun membranes. In response to diminished protein adsorption, mRNA expression of genes related to cell adhesion and migration was up‐regulated. The limited effects of pure PEG were probably caused by its preferential dissolution, whereas membrane‐confined PLLGA–PEG displayed excellent performance on the inhibition of protein adsorption and cell proliferation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2897–2904, 2012.
ACL reconstruction using a novel hybrid scaffold composed of polyarylate fibers and collagen fibers
Authors: Tovar Nick , Murthy N. Sanjeeva , Kohn Joachim , Gatt Charles , Dunn Michael 
Published: June 2012

AbstractThe objective was to perform an initialin vivoevaluation of a novel braided hybrid polyarylate and collagen fiber scaffold for the reconstruction of the anterior cruciate ligament (ACL). The braided hybrid scaffold is composed of 75% poly(desaminotyrosyl‐tyrosine dodecyl dodecanedioate)(12,10), [p(DTD DD)] fibers and 25% type I bovine collagen fibers. The scaffold is designed to temporarily bear mechanical loads and gradually degrade as neoligament tissue is deposited. Scaffolds were electron beam sterilized and used to reconstruct the ACL in five Finnish Dorset crossed‐bred sheep in this feasibility study. At 4 (n= 1) and 12 (n= 4) weeks post‐op, scaffolds were retrieved and analyzed for cellular ingrowth and strength retention. There was extensive cell infiltration and vascularity, which increased with time. Tissue ingrowth occurred throughout the cross section in the midsubstance of the scaffolds. After 12 weeks all scaffolds were intact. Femur–scaffold–tibia complex (FSTC) explanted at 12 weeks had a yield load of 42 ± 22 N and a stiffness of 9 ± 3 N mm−1. All scaffolds were well tolerated in the intraarticular space and induced tissue ingrowth, including new blood vessels, fibroblasts, inflammatory cells, and newly deposited collagen, throughout the cross section of the scaffold. Tissue ingrowth is critical to the success of a degradable scaffold for ACL reconstruction. Long‐term studies in a large animal model are required to determine the efficacy of these novel hybrid scaffolds for ACL reconstruction. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2913–2920, 2012.
Osteogenic differentiation of bone marrow mesenchymal stem cells on the collagen/silk fibroin bi‐template‐induced biomimetic bone substitutes
Authors: Wang Jianglin , Yang Qin , Mao Chuanbin , Zhang Shengmin 
Published: June 2012

AbstractBiomimetic bone substitutes of collagen‐silk fibroin/hydroxyapatite (COL‐SF/HA) were synthesized via a bi‐template‐induced coassembly strategy. Collagen‐hydroxyapatite (COL‐HA) and silk fibroin‐hydroxyapatite (SF‐HA) served as controls were prepared with similar method. The osteogenic differentiation ability of bone marrow mesenchymal stem cells (BMSCs) seeded onto the resulting materials was evaluated both in vitro and in vivo. The results suggested that the bi‐template‐induced biomimetic substitutes were able to support the growth and proliferation of BMSCs. We further demonstrated that BMSCs were stimulated to differentiate into the osteoblast cell lineage by evaluating several specific osteogenic markers including staining of alkaline phosphate (ALP) and calcium nodular and expression of osteogenic genes of osteocalcin (OCN) and osteonectin (ONN). The rat femoral defect model was used to assess the aforementioned biomimetic bone substitutes combined with BMSCs in vivo. Histological analysis indicated that the bi‐template material exhibited good biocompatibility and strong ability of the new bone formation in comparison with the control of single‐template material in vivo. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2929–2938, 2012.
Structural study and preliminary biological evaluation on the collagen hydrogel crosslinked by γ‐irradiation
Authors: Zhang Xiangmei , Xu Ling , Huang Xin , Wei Shicheng , Zhai Maolin 
Published: June 2012

AbstractUnder γ‐irradiation, concentrated collagen solutions yielded collagen hydrogels and liquid products. The molecular structure of collagen hydrogels and the source of the liquid products were studied. Furthermore, preliminary biological properties of the hydrogels were investigated. The results revealed that crosslinking occurred to form collagen hydrogel and the crosslinking density increased with the increasing of the absorbed dose, and the collagen hydrogels showed enhanced mechanical properties. Meanwhile, collagen underwent radiation degradation and water was squeezed out from hydrogel by contraction of hydrogel, yielding liquid products. Collagen hydrogels induced by γ‐irradiation maintained the backbone structure of collagen, and tyrosine partially involved in crosslinking. The irradiated collagen hydrogels have higher denatured temperature, can promote fibroblasts proliferation, and their degradation rate in vivo depended on the absorbed dose. The comprehensive results suggested that the collagen hydrogels prepared by radiation crosslinking preserved the triple helical conformation, possessed improved thermal stability and mechanical properties, excellent biocompatibility, which is expected to favor its application as biomaterials. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:2960–2969, 2012.
An electronic structure theory investigation of the physical chemistry of the intermolecular complexes of cyclopropenylidene with hydrogen halides
Authors: Varadwaj Pradeep R. , Varadwaj Arpita , Peslherbe Gilles H. 
Published: June 2012

AbstractThe proton accepting and donating abilities of cyclopropenylidene (c‐C3H2) on its complexation with hydrogen halides HX (X = F, Cl, Br) are analyzed using density‐functional theory with three functionals (PBE0, B3LYP, and B3LYP‐D) and benchmarked against second‐order Møller–Plesset (MP2) theory. Standard signatures including,inter alia, dipole moment enhancement, charge transfer from the carbenic lone pair to the antibonding σ*(HX) orbital, and HX bond elongation are examined to ascertain the presence of hydrogen bonding in these complexes. The latter property is found to be accompanied with a pronounced red shift in the bond stretching frequency and with a substantial increase in the infrared intensity of the band on complex formation. The MP2/aug‐cc‐pVTZ c‐C3H2···HF complex potential energy surface turns out to be an asymmetric deep single well, while asymmetric double wells are found for the c‐C3H2···HCl and c‐C3H2···HBr complexes, with an energy barrier of 4.1 kcal mol−1for proton transfer along the hydrogen bond in the latter complex. Hydrogen‐bond energy decomposition, with the reduced variational space self‐consistent field approach, indicates that there are large polarization and charge‐transfer interactions between the interacting partners in c‐C3H2···HBr compared to the other two complexes. The C···H bonds are found to be predominantly ionic with partial covalent character, unveiled by the quantum theory of atoms in molecules. The present results reveal that the c‐C3H2carbene divalent carbon can act as a proton acceptor and is responsible for the formation of hydrogen bonds in the complexes investigated. © 2012 Wiley Periodicals, Inc.
Structure and stability of coinage metal fluoride and chloride clusters (MnFn and MnCln, M = Cu, Ag, or Au; n = 1–6)
Authors: Rabilloud F. 
Published: June 2012

AbstractCalculations in the framework of the density functional theory are performed to study the lowest‐energy isomers of coinage metal fluoride and chloride clusters (MnFn, MnCln, M = Cu, Ag, or Au, n = 1–6). For all calculated species starting from the trimers the most stable structures are found to be cyclic arrangements. However, planar rings are favored in the case of metal fluorides whereas metal chlorides prefer nonplanar cycles. Calculated bond lengths and infrared frequencies are compared with the available experimental data. The nature of the bonding, involving both covalent and ionic contributions, is characterized. The stability and the fragmentation are also investigated. Trimers are found to be particularly stable when considering the Gibbs free energies. © 2012 Wiley Periodicals, Inc.
Intracolonically administered adeno‐associated virus‐bone morphogenetic protein‐7 ameliorates dextran sulphate sodium‐induced acute colitis in rats
Authors: Hao Zhiming , Yang Xiaofei , Lv Yifei , Li Shuang , Purbey Bibek Kumar , Su Houqiang 
Published: June 2012

AbstractBackgroundThe current treatment of ulcerative colitis (UC) is less than ideal and has room for improvement. Bone morphogenetic protein‐7 (BMP‐7) exerts a protective effect on experimental UC. Hence, we considered that intracolonically (i.c.) administered adeno‐associated virus (AAV) delivering BMP‐7 might have therapeutic potential for UC.MethodsRecombinant AAV type 2 vectors carrying enhanced green fluorescence protein (AAV‐EGFP), LacZ (AAV‐LacZ) and BMP‐7 (AAV‐BMP‐7) were generated. Bioluminescence imaging, β‐galactosidase assay and western blotting were applied to determine the colonic expression of EGFP, LacZ and BMP‐7, respectively, after i.c. administration of the AAVs. Disease activity index (DAI) was observed daily during the 7 days of dextran sulphate sodium (DSS) treatment initiated 4 days after i.c. AAV‐BMP‐7, AAV‐LacZ or phosphate‐buffered saline. The colonic pathological morphology, mucosal myeloperoxidase (MPO) activity, malondialdehyde content, superoxide dismutase activity and proliferating cell nuclear antigen were determined at the end of DSS treatment.ResultsWhen i.c administered to rats, AAV could efficiently transduce the colonic mucosa. Enema with AAV‐BMP‐7 significantly ameliorated DSS‐induced colitis as indicated by reduced DAI, decreased macroscopic and histological scores and declined MPO activity compared to the controls. Furthermore i.c. AAV‐BMP‐7 significantly prevented oxidant damage and attenuated complementary mucosal cell proliferation in the DSS‐treated rat colons.ConclusionsOur data demonstrate that i.c. administration of AAV‐BMP‐7 efficiently mediates the ectopic BMP‐7 expression in rat colon and further ameliorates DSS‐induced UC in rats, suggesting that i.c. AAV‐BMP‐7 has the potential to be developed into an alternative therapeutic measure for the treatment of UC. Copyright © 2012 John Wiley & Sons, Ltd.