bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theories of cognition and image categorization: What category labels reveal about basic level theory
Authors: Rorissa Abebe , Iyer Hemalata 
Published: April 2008

AbstractInformation search and retrieval interactions usually involve information content in the form of document collections, information retrieval systems and interfaces, and the user. To fully understand information search and retrieval interactions between users' cognitive space and the information space, researchers need to turn to cognitive models and theories. In this article, the authors use one of these theories, the basic level theory. Use of the basic level theory to understand human categorization is both appropriate and essential to user‐centered design of taxonomies, ontologies, browsing interfaces, and other indexing tools and systems. Analyses of data from two studies involving free sorting by 105 participants of 100 images were conducted. The types of categories formed and category labels were examined. Results of the analyses indicate that image category labels generally belong to superordinate to the basic level, and are generic and interpretive. Implications for research on theories of cognition and categorization, and design of image indexing, retrieval and browsing systems are discussed.
Homolytic SS Bond Dissociation of 11 Bis(thiocarbonyl)disulfides R‐C(S)SSC(S)R and Prediction of A Novel Rubber Vulcanization Accelerator
Authors: Mak Adrian Matthew , Steudel Ralf , Wong Ming Wah 
Published: April 2008

AbstractThe structures and energetics of eight substituted bis(thiocarbonyl)disulfides (RCS2)2, their associated radicals RCS2., and their coordination compounds with a lithium cation have been studied at the G3X(MP2) level of theory for R=H, Me, F, Cl, OMe, SMe, NMe2, and PMe2. The effects of substituents on the dissociation of (RCS2)2 to RCS2. were analyzed using isodesmic stabilization reactions. Electron‐donating groups with an unshared pair of electrons have a pronounced stabilization effect on both (RCS2)2 and RCS2.. The SS bond dissociation enthalpy of tetramethylthiuram disulfide (TMTD, R=NMe2) is the lowest in the above series (155 kJ mol−1), attributed to the particular stability of the formed Me2NCS2. radical. Both (RCS2)2 and the fragmented radicals RCS2. form stable chelate complexes with a Li+ cation. The SS homolytic bond cleavage in (RCS2)2 is facilitated by the reaction [Li(RCS2)2]++Li+→2 [Li(RCS2)].+. Three other substituted bis(thiocarbonyl) disulfides with the unconventional substituents R=OSF5, Gu1, and Gu2 have been explored to find suitable alternative rubber vulcanization accelerators. Bis(thiocarbonyl)disulfide with a guanidine‐type substituent, (Gu1CS2)2, is predicted to be an effective accelerator in sulfur vulcanization of rubber. Compared to TMTD, (Gu1CS2)2 is calculated to have a lower bond dissociation enthalpy and smaller associated barrier for the SS homolysis.
Insulin-like growth factor I improves aspects of mycophenolate mofetil-impaired anastomotic healing in an experimental model
Authors: Inglin R A , Baumann G , Wagner O J , Candinas D , Egger B 
Published: April 2008

AbstractBackgroundPatients taking immunosuppressants after transplantation may require intestinal surgery. Mycophenolate mofetil (MMF) has been found to impair the healing of colonic anastomoses in rats. This study examined whether insulin-like growth factor (IGF) I prevents MMF impairment of anastomotic healing.MethodsSixty-three rats were divided into three groups (MMF, MMF/IGF and control). Animals underwent a sigmoid colon anastomosis with a 6/0 suture, and were killed on days 2, 4 and 6 after surgery. Investigations included bursting pressure measurement, morphometric analysis, and assessment of mucosal proliferation by 5-bromo-2′-deoxyuridine and Ki67 immunohistochemistry of the anastomoses.ResultsThe leak rate was three of 21, one of 20 and two of 20 in the MMF, MMF/IGF-I and control groups respectively. Anastomotic bursting pressures were significantly lower in the MMF group than in the control group on days 2 and 4, but there was no significant difference by day 6. Values in the MMF/IGF-I and control groups were similar. Colonic crypt depth was significantly reduced in MMF-treated animals on days 2 and 4, but this impairment was attenuated by IGF-I on day 4. Similarly, IGF-I reduced the negative impact of MMF on mucosal proliferation on days 2 and 6.ConclusionExogenous IGF-I improves some aspects of MMF-impaired anastomotic healing.
Impact of body mass index and tobacco smoking on outcome after open appendicectomy
Authors: Sadr Azodi O , Lindström D , Adami J , Bellocco R , Linder S , Wladis A 
Published: April 2008

Abstract

Background
The effect of body mass index (BMI) and smoking on the risk of perforated appendix and postoperative complications in patients undergoing open appendicectomy for acute appendicitis was studied.

Methods
Record linkage was used to identify 6676 male construction workers who underwent open appendicectomy for acute appendicitis between 1971 and 2004. Multivariable binomial logistic regression analyses were performed.

Results
After adjustment for age, calendar period and BMI, smoking was significantly associated with an increased risk of perforated appendicitis (PA) (P = 0·004). The relative risk was 1·29 (95 per cent confidence interval 1·11 to 1·50) among current smokers with more than 10 pack-years of tobacco use. In patients with non-perforated appendicitis (NPA), the relative risk of overall postoperative complications was significantly associated with BMI (P &lt; 0·001), and was 2·60 (1·71 to 3·95) in obese patients and 1·51 (1·03 to 2·22) in current smokers with more than 10 pack-years of tobacco use. In patients with PA, overweight, obesity and smoking status were not associated with an increased risk of overall postoperative complications.

Conclusion
Perforation due to acute appendicitis was associated with current tobacco smoking. A BMI of 27·5 kg/m2 or more and current smoking were associated with overall postoperative complications in patients with NPA.
APC mutation spectrum in ileoanal pouch polyps resembles that of colorectal polyps
Authors: Will O C C , Robinson J , Günther T , Phillips R K S , Clark S K , Tomlinson I 
Published: April 2008

Abstract

Background
Ileoanal pouch polyps commonly develop following restorative proctocolectomy in patients with familial adenomatous polyposis (FAP). In FAP adenomas, the relationship between germline and somatic adenomatous polyposis coli (APC) mutations is determined by ‘just right’ β-catenin signalling in tumour cells, with respect to the 20-amino acid β-catenin-binding/degradation repeats (20AARs) in the APC protein. However, the relationship varies, with upper gastrointestinal polyps typically retaining three to four 20AARs and colonic polyps retaining one or two. The aim of this study was to establish the mutational spectrum in ileoanal pouch polyps, to ascertain whether polyp development resembled that typical of small or large bowel.

Methods
Some 151 pouch adenomas were screened from 46 patients with known germline APC mutations for ‘second hits’ acquired through loss of heterozygosity and truncating mutations. The number of 20AARs remaining after the ‘second hit’ was calculated.

Results
Loss of heterozygosity was rare in pouch polyps except when the germline mutation left one 20AAR. Overall, the combined alleles left two to three 20AARs in 40 of 51 polyps with an identified ‘second hit’. This was significantly fewer than in upper gastrointestinal polyps, and more than in colorectal adenomas.

Conclusion
Tissue environment appears to influence the position of the ‘second hit’ in pouch polyps and the mutations resemble those of large bowel polyps.
Nitric oxide reduces organ injury and enhances regeneration of reduced-size livers by increasing hepatic arterial flow
Authors: Cantré D , Schuett H , Hildebrandt A , Dold S , Menger M D , Vollmar B , Eipel C 
Published: April 2008

Abstract

Background
Reduced-size livers suffer from portal hyperperfusion, diminished arterial blood flow and the risk of postoperative liver injury. The aim of this experimental study was to unravel the role of nitric oxide in this setting.

Methods
Rats underwent 85 per cent partial hepatectomy and either substitution of nitric oxide with molsidomine or inhibition of nitric oxide synthase (NOS) with NG-nitro-l-arginine methyl ester. Untreated hepatectomized animals served as controls and unresected animals as the sham group.

Results
Ultrasonic flowmetry following partial hepatectomy revealed a marked increase in portal venous inflow with a concomitant decrease in hepatic arterial inflow. Nitric oxide substitution counteracted the decline in hepatic arterial inflow and caused a significantly greater increase in cell proliferation after partial hepatectomy compared with control or NOS-inhibited animals. Hepatectomized animals further profited from nitric oxide substitution, as indicated by reduced aminotransferase release and improved liver function.

Conclusion
Nitric oxide improves the postoperative course of rats with reduced-size livers by modulating hepatic macrohaemodynamics and mediating regeneration and cytoprotection, but not by reducing hepatic hyperperfusion and the accompanying sinusoidal shear stress.
Tuning the Magnetic Properties of LixCrTi0.25Se2(0.03≤x≤0.7) by Directed Deintercalation of Lithium
Authors: Behrens Malte , Wontcheu Joseph , Kiebach Ragnar , Bensch Wolfgang 
Published: April 2008

AbstractX‐ray diffraction (XRD), in situ energy‐dispersive X‐ray diffraction (EDXRD), X‐ray absorption near‐edge structure (XANES), extended X‐ray absorption fine structure (EXAFS), and magnetic measurements were applied to investigate the effects of lithium deintercalation on pseudolayered Li0.70CrTi0.25Se2. A detailed picture of structural changes during the deintercalation process was obtained by combining the results of EDXRD and EXAFS. Removal of Li from the host–guest complex leads to anisotropic contraction of the unit cell with stronger impact on thecaxis, which is the stacking axis of the layers. The EDXRD experiments evidence that the shrinkage of the lattice parameters with decreasingxLiin LixCrTi0.25Se2is nonlinear in the beginning and then becomes linear. Analysis of the EXAFS spectra clearly shows that the Cr/TiSe distances are affected in a different manner by Li removal. The CrSe bond lengths decrease, whereas the TiSe bonds lengthen when the Li content is reduced, which is consistent with XRD data. Magnetic measurements reveal a change from predominantly antiferromagnetic exchange (θp=−300 K) interactions for the pristine material to ferromagnetic exchange interactions (θ=25 K) for the fully intercalated material. Thus, the magnetic properties can be altered under ambient conditions by directed adjustment of the dominant magnetic exchange. The unusual magnetic behavior can be explained on the basis of the variation of the metal–metal distances and the Cr‐Se‐Cr angles withx, which were determined by Rietveld refinements. Owing to competing ferromagnetic and antiferromagnetic exchange interactions and disorder, the magnetic ground state of the intercalated materials is characterized by spin‐glass or spin‐glass‐like behavior.
Diverse Reactions of 1,4‐Dilithio‐1,3‐dienes with Nitriles: Facile Access to Tricyclic Δ1‐Bipyrrolines, Multiply Substituted Pyridines, Siloles, and (Z,Z)‐Dienylsilanes by Tuning of Substituents on the Butadienyl Skeleton
Authors: Yu Nan , Wang Congyang , Zhao Fei , Liu Lantao , Zhang Wen‐Xiong , Xi Zhenfeng 
Published: April 2008

AbstractAddition cyclization of 1,2,3,4‐tetrasubstituted 1,4‐dilithio‐1,3‐dienes (Type I) with four equivalents of various aromatic nitriles in the presence of hexamethylphosphoramide (HMPA) gives exclusively fully substituted pyridines in moderate to good yields. Similarly, trisubstituted pyridines can be prepared by the reaction of 2,3‐dialkyl‐ or diaryl‐substituted 1,4‐dilithio‐1,3‐dienes (Type II) with nitriles. However, five‐ or six‐membered‐ring fused 2,3‐disubstituted 1,4‐dilithio‐1,3‐dienes (Type III) reacted with various aromatic and aliphatic nitriles without α‐hydrogen atoms to afford tricyclic Δ1‐bipyrrolines in high yields. The reaction of six‐membered‐ring fused 2,3‐disubstituted 1,4‐dilithio‐1,3‐diene (Type III) with 2‐cyanopyridine afforded the corresponding pyridine, and no tricyclic Δ1‐bipyrroline was observed. Seven‐membered‐ring fused dilithiodienes reacted with PhCN or trimethylacetonitrile to afford the corresponding pyridines in good yield. When 1,2,3,4‐tetrasubstituted dilithio reagents (Type I) were treated with Me3SiCN, a tandem silylation/intramolecular substitution process readily occurred to yield siloles, whereas the reaction of 2,3‐disubstituted dilithio reagents (Types II and III) with Me3SiCN gave rise to (Z,Z)‐dienylsilanes with high stereoselectivity. These results revealed that the formation of tricyclic Δ1‐bipyrrolines, pyridines, siloles, and (Z,Z)‐dienylsilanes are strongly dependent on the substitution patterns of the dilithio butadienes and the nature of the nitriles employed.
Clusterization, Electrophoretic Deposition, and Photoelectrochemical Properties of Fullerene‐Functionalized Carbon Nanotube Composites
Authors: Umeyama Tomokazu , Tezuka Noriyasu , Fujita Mitsuru , Hayashi Shinya , Kadota Naoki , Matano Yoshihiro , Imahori Hiroshi 
Published: April 2008

AbstractWe have successfully developed a new methodology for the self‐organization of C60 molecules on the sidewall of carbon nanotubes for use in photoelectrochemical devices. Novel nanocarbon composites of fullerene (e.g., C60) and highly soluble, chemically functionalized single‐walled carbon nanotubes (f‐SWNT) have been prepared by the rapid injection of a poor solvent (e.g., acetonitrile) into a mixed solution of C60 and f‐SWNT in o‐dichlorobenzene. Measurements by using scanning electron microscopy of cast samples revealed that the composites are categorized into three groups; i) f‐SWNT bundles covered with layers of C60 molecules, ii) round, large C60 clusters (sizes of 500–1000 nm) containing f‐SWNT, and iii) typical, round C60 clusters (sizes of 150–250 nm). The electrophoretic deposition of the composites onto a nanostructured SnO2 electrode yielded the hierarchical film with a gradient composition depending on the difference in the mobilities of C60 and f‐SWNT during the electrophoretic process. The composite film exhibited an incident photon‐to‐photocurrent efficiency as high as 18 % at λ=400 nm under an applied potential of 0.05 V vs. SCE. The photocurrent generation efficiency is the highest value among carbon nanotube‐based photoelectrochemical devices in which carbon nanotubes are deposited electrophoretically, electrostatically or covalently onto semiconducting electrodes. The highly aligned structure of C60 molecules on f‐SWNT can rationalize the efficient photocurrent generation. The results obtained here will provide valuable information on the design of carbon nanotube‐based molecular devices.
Size‐ and Structure‐Selective Noncovalent Recognition of Saccharides by Tetraethyl and Tetraphenyl Resorcinarenes in the Gas Phase
Authors: Kalenius Elina , Kekäläinen Timo , Neitola Raisa , Beyeh Kodiah , Rissanen Kari , Vainiotalo Pirjo 
Published: April 2008

AbstractThe noncovalent complexation of tetraethyl and tetraphenyl resorcinarenes with mono‐, di‐, and oligosaccharides was studied with negative‐polarization electrospray ionization quadrupole ion trap and electrospray ionization Fourier‐transform ion cyclotron resonance mass‐spectrometric analysis. The saccharides formed 1:1 complexes with deprotonated resorcinarenes, which exhibited clear size and structure selectivity in their complexation. In the case of the monosaccharides, hexoses formed much more abundant and kinetically stable complexes than pentoses or deoxyhexoses. A comparison of the mono‐, di‐, and oligosaccharides revealed that both the relative abundance and stability of the complexes increase up to biose and triose, but start to decrease after that point, as the length of the oligosaccharide is increased. This behavior was rationalized by comparing the lowest‐energy conformations of the complexes formed between the resorcinarene and oligosaccharides. This comparison was achieved by using theoretical calculations and X‐ray crystal studies.
Kinetics and Mechanism for Oxidation of L‐Proline by Bis(hydrogen periodato)argentate(III) Complex Anion
Authors: SUN Han‐Wen , SHI Hong‐Mei , SHEN Shi‐Gang , KANG Wei‐Jun , GUO Zhi‐Feng 
Published: April 2008

AbstractOxidation of L‐proline by bis(hydrogen periodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C by use of conventional spectrophotometry. Under the conditions for kinetic measurements, the oxidation results in decarboxylation of proline, giving rise to γ‐aminobutyrate as identified by mass spectrometry. The oxidation kinetics is first order with respect to the silver(III) and proline concentrations; the second‐order rate constants, decreasing with increasing [periodate], are essentially independent of [OH−]. The kinetic results were interpreted in terms of a reaction mechanism which involves a pre‐equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono‐periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced parallelly by the fully deprotonated form of proline in rate‐determining steps (described by k1 for the former Ag(III) and k2 for the latter one). The determined rate constants and their associated activation parameters are k1(25 °C) = (1.87±0.04) L·mol−1·s−1, ΔH1≠= (45±4) kJ· mol−1, ΔS1≠= (−90±13) J·K−1·mol−1 and k2(25 °C) = (3.2±0.5) L·mol−1·s−1, ΔH2≠= (34±2) kJ·mol−1, ΔS2≠= (−122±10) J·K−1·mol−1. This is also the first time to find that [Ag(HIO6)2]5− is also reactive toward a particular reductant and shows a lower reactivity than [Ag(HIO6)(OH)(H2O)]2−.
Reduction of Methylene Green by EDTA:Kinetic and Thermodynamic Aspects
Authors: AZMAT Rafia , QAMAR Noshab , SAEED Amber , UDDIN Fahim 
Published: April 2008

AbstractThe reduction of methylene green (MG) into protonated leuco dye with ethylenediamine tetraacetic acid (EDTA) in aqueous alkaline medium was studied spectrophotometrically at λmax 660 nm. EDTA behaved as an effective electron donor during the reduction of MG in an aerobic condition. Consumption of EDTA in the reduction of MG means that it is oxidized. This is an unexpected result since EDTA does not normally function as a reducing agent. The nitrogen‐containing chelating agents with secondary or tertiary nitrogen behaved as an electron donor in photochemical reaction of dye. The rate of reduction depends upon pH in the same way as the base titration of EDTA. Effects of salt and temperature have been investigated for the reduction process. The salting agent KNO3 has been found to uniquely enhance the rate of reduction of MG by EDTA in the aerobic condition. Detailed kinetic and thermodynamic aspects have been discussed to realize the interaction between MG and EDTA. Kinetic studies revealed that reaction was sensitive and regeneration of oxidized form of the dye was observed. Reversible first order reaction kinetics with respect to EDTA, MG and NaOH was found.
Highly Sensitive Thin Film Sensor Based on Worm‐like Carbon Nanofibers for Detection of Ammonia in Workplace
Authors: WANG Jia‐Zhi , CHEN Xing , LI Min‐Qiang , LIU Jin‐Huai 
Published: April 2008

AbstractA thin film sensor was fabricated using the mixture of worm‐like carbon nanofibers (WCNF), which were synthesized using aluminium supported iron catalysts via chemical vapour deposition, and glass dust in proportion of 3:2, combined by drops of terpineol. The morphology of the catalyst, the worm‐like carbon nanofibers and the film surface were investigated with the help of TEM and SEM. Low single‐potential signal was employed to investigate gas sensitivity of the sensor to the deleterious ammonia, in atmospheric pressure at room temperature. The results suggest that the sensor has high sensitivity at low concentration (0.175–0.35 mg/m3), perfect reproducibility, and a fast response time (0.05 s) and restoration time (1 min).
Investigation of the Interaction between Adenosine and Human Serum Albumin by Fluorescent Spectroscopy and Molecular Modeling
Authors: CUI Feng‐Ling , WANG Jun‐Li , LI Fang , FAN Jing , QU Gui‐Rong , YAO Xiao‐Jun , LEI Bei‐Lei 
Published: April 2008

AbstractThe binding interaction of adenosine with human serum albumin (HSA) was investigated under simulative physiological conditions by fluorescence spectroscopy in combination with a molecular modeling method. A strong fluorescence quenching reaction of adenosine to HSA was observed and the quenching mechanism was suggested as static quenching according to the Stern‐Volmer equation. The binding constants (K) at different temperatures as well as thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS), were calculated according to relevant fluorescent data and Vant′Hoff equation. The hydrophobic interaction was a predominant intermolecular force in order to stabilize the complex, which was in agreement with the results of molecular modeling study.
Quantitative Retention‐Activity Relationship Studies by Liposome Electrokinetic Chromatography to Predict Skin Permeability
Authors: XIAN De‐Ling , HUANG Ke‐Long , LIU Su‐Qin , XIAO Jing‐Yi 
Published: April 2008

AbstractLiposome electrokinetic chromatography (LEKC) provides a simple and facile approach for drug membrane interactions using liposome as a pseudostationary phase. This study evaluated the potential of LEKC for high‐throughput skin permeability profiled as an in vitro technique. A quantitative retention‐activity relationship (QRAR) model for the estimation of skin permeability was proposed. For the 16 structurally diverse chemicals, lg k correlated well with permeability values (R2=0.886). The predictive ability of the model was evaluated by cross‐validation. The result was compared to traditional quantitative structure‐activity relationship, QSAR, models using some molecular descriptors and physicochemical parameters. Interestingly, a single LEKC retention parameter was capable of describing the skin permeability, while three variables in QSAR were needed to achieve a similar correlation (R2=0.704). The QRAR models developed in this paper may be a useful method to screening new chemicals and in the early stage of development and selection of chemicals.
Uracil Grafted Carbon Electrode:Electrocatalytic Behavior of Tryptophan, Tyrosine, Catecholamine and Related Compounds
Authors: LIN Xiang‐Qin , KANG Guang‐Feng , ZHU Xiao‐Hong 
Published: April 2008

AbstractA uracil grafted glassy carbon electrode (Ura/GCE) was fabricated and characterized by X‐ray photoelectron spectroscopy (XPS), cyclic voltammertry (CV) and differential pulse voltammetry (DPV) techniques. The electrochemical behavior of tryptophan (Trp), tyrosine (Tyr), catecholamine such as dopamine (DA), epinephrine (EP) and norepinephrine (NE), and related compounds involving uric acid (UA) and ascorbic acid (AA) at the Ura/GCE was investigated. All these bioactive species could be electrocatalytically oxidized to generate very different current sensitivities. This electrode can be used as a versatile electrochemical sensor for DA, EP, NE, UA, Trp and Tyr determination. The DPV peak potential, current sensitivity, linear range and detection limit of these species were obtained and used for analysis of molecular interactions between uracil and those electroactive species. A mechanism for the surface accumulation was discussed.
A Versatile Approach for the Total Syntheses of Fuscinarin and Fuscins
Authors: DU Chao , LI Li‐Qi , DA Shi‐Jun , LI Ying , XIE Zhi‐Xiang 
Published: April 2008

AbstractThe first total synthesis of fuscinarin (1) and total synthesis of fuscins, the pentaketide metabolites showing activity against CCR5 in a scintillation proximity assay, were described by using compound 6 as a common intermediate. A key feature of the approach is the microwave‐assisted tandem ortho‐Claisen/Cope rearrangement that was used for the expedient synthesis of the intermediate 10.