bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Recent Developments in NMR Approaches for Studying Liquid Molecular Dynamics and Their Biological Applications
Authors: Price William S. , Hwang Lian‐Pin 
Published: June 2015

AbstractTwo aspects of NMR relaxation are reviewed and their use in studying molecular dynamics in the liquid state and their application to biological systems are discussed. The first aspect concerns the use of ‘null‐point spectra’ for observing the effects of higher rank multipoles (tensors) in the relaxation of quadrupolar nuclei. The second aspect concerns the effects of cross‐correlation in homo‐ and heteronuclear spin systems. The application of null point spectral analysis to study cross‐correlation in homonuclear spin systems is also discussed. Analysis of the effects of higher rank multipoles and of cross‐correlation effects are shown to provide substantially more structural and motional information about spin systems than that available from traditional relaxation measurements. While similar in information content to multiple quantum techniques, the null point technique is experimentally less demanding. Over the past several years, work in this laboratory has been heavily involved in the theoretical formulation and the application of these techniques to biological systems. Illustrations of the use of these techniques to biological systems are drawn from our recent work.
Imaging Techniques in Experiments on Dynamics
Authors: Chen Kuo‐Mei , Kuo Chen‐Nan 
Published: June 2015

AbstractSpatial distributions of dynamic systems with resolved translational energy and selected internal states provide indispensable information about the corresponding physical and chemical mechanisms. From an experimental viewpoint, two‐dimensional imaging techniques are well suited to explore dynamic aspects of collisional processes. The advantages of imaging techniques over conventional methods are demonstrated in laser ablation of metal targets and collisionally induced electronic excitation of metal atoms. Approaching the ultimate goal in chemical dynamics, a unique method which combines laser‐induced fluorescing illumination and gated two‐dimensional imaging techniques can directly measure the three‐dimensional distributions of number density, angle and velocity of scattered products from photofragmentation and from inelastic and reactive collisions in the center‐of‐mass frame. The physical principle behind this direct method and its experimental arrangement are outlined.
Dynamics and Kinetics of Metal Atoms in the Gas Phase
Authors: Lin King‐Chuen 
Published: June 2015

AbstractThe review is divided into four sections. We first consider the varied behavior of K n2S and n2D states in their chemical reactivity and physical characterization. We review the effect of orbital alignment of an electronically excited metal atom on the cross section of energy transfer or chemical reaction, and report the technique of a single supersonic jet employed to measure this effect on the Ca spin‐changing collision. We discuss the effects of temperature and isotopic mass on the distribution of rotational quantum number of the product MgH to identify the reaction mechanism of Mg(1P1) + H2. The final concerns are the quantum yield, fine‐structure branching ratio and rate of collisional mixing for the K 2PJ doublets following photodissociation of KI at 193 nm.
New Aspects Concerning Chelating Resins
Authors: Liu Chuen‐Ying 
Published: June 2015

AbstractObject of the present paper is to provide an up‐to‐date overview the application of chelating resins, a functional polymer of a special kind. Attention has been in particular limited to the field of ligand exchange chromatography, sample handling and trace enrichment, metal‐ion buffers and polymer catalysts with enzyme‐like activities. The fundamental principles in the design and syntheses of chelating resins for usage in these respects are also described.
Chemistry of Heterometallic Cluster Compounds Prepared by Condensation of Group 6 Metal Acetylide and Group 8 Binary Carbonyl Complexes
Authors: Chi Yun 
Published: June 2015

AbstractThe chemistry of trinuclear and tetranuclear heterometallic acetylide complexes, LWOs3(CO)11(CCR) and LWM2(CO)8(CCR), L = Cp and Cp*; M = Os and Ru, is presented. Included in this account are syntheses, characterization and reactivity, with a particular focus on reactions with disubstituted alkyne molecules. The reactivity and fluxionality of these acetylide complexes provides a plausible model for ligand‐mediated metal‐core rearrangement and the transformation of small organic molecules on catalytic metal surfaces.
Syntheses of Iso‐Condensed Heteroaromatic Pyrroles
Authors: Sha Chin‐Kang , Tsou Chiu‐Peng , Tsai Chung‐Yin , Liu Jia‐Ming , Lee Ren‐Sheng , Li Yu‐Chang , Tsai Fu‐Yuan , Way Shiow‐Jye , Young Jenn‐Jong , Chuan Kuang‐Sein , Yeh Ren‐Hwa 
Published: June 2015

AbstractThree novel reactions for the synthesis of iso‐condensed heteroaromatic pyrroles: (1) tandem intramolecular 1,3‐dipolar cycloaddition and cycloreversion reaction; (2) phosphineimine‐alkylidenemalonate cyclization reaction; (3) retromalonate addition reaction, are described. They can be used in acidic, neutral or basic conditions respectively. Iso‐condensed heteroaromatic pyrroles, such as pyrrolo[3,4‐b]indole 12, pyrrolo[3,4‐b]pyridine 17, pyrrolo[3,4‐c]pyridine 18, thieno[2,3‐c]pyrrole 37, pyrrolo[3,4‐b]pyrrole 40, pyrrolo[3,4‐b]pyrazine 49, benzofuro[2,3‐c]pyrrole 50, 1,2‐bis[5‐thieno[2,3‐c]pyrrolyl]ethane 51, 1,4‐bis[5‐thieno[2,3‐c]pyrrolyl]benzene 52, dipyrrolo[3,4‐b;3′,4′‐d]dipyrroles 55 and 56, benzotripyrroles 62–64, and thieno[3,4‐c]pyrroles 67 and 73 are synthesized efficiently according to these methods.
Chemistry of Sydnone Compounds
Authors: Kuo Chao‐Nan , Wang Shao‐Pin , Yeh Mou‐Yung , Tien Hsien‐Ju 
Published: June 2015

AbstractA review of sydnone chemistry is divided into two major parts, describing methods developed to prepare sydnone derivatives and syntheses starting from sydnones. Spectral studies of the structural characterization of sydnones are summarized in the conclusion.
Chemical Activation of Amides to Their Mutagenic and Carcinogenic Derivatives
Authors: Lin Jen‐Kun 
Published: June 2015

AbstractMost amides are stable compounds, but they are convertible to extremely reactive metabolites by microsomal enzymes. The amide drugs phenacetin and acetaminophen are converted to the toxic metabolite N‐acetyl‐p‐benzoquinoneimine by a combination of several cytochrome P‐450 systems. The well known hepatocarcinogen 2‐acetylaminofluorene (AAF) is metabolically activated to a highly electrophilic reactant that interacts with DNA, RNA and proteins. There are other alternative pathways which may actviate these amide compounds; nitrosation of these amides yield several directly acting mutagens, teratogens and carcinogens. We have synthesized several new N‐nitroso compounds, namely N‐nitrosophenacetin, N‐nitrosoacetaminophcn and N‐nitroso‐2‐acetylaminofluorene (NO‐AAF). The chemical structures of these compounds were characterized by spectrometric analysis of their naphthol‐coupling derivatives. The new compounds are highly mutagenic to Salmonella tester strains TA 97, TA 98, TA 100 and TA 1538 and require no microsomal metabolic activation. NO‐AAF in TA 98 is more mutagenic than MNNG and N‐acetoxy‐AAF. The teratogenic potentials of NO‐AAF and N‐nitrosophenacetin were studied with white Leghorn chick embryo. A high incidence of flaccid paralysis of the legs and a low incidence of feather, claw and bill malformations were found in the treated group; no such malformed embryos were found in the control group. Both N‐nitrosophenacetin and NO‐AAF are strong electrophiles and react readily with amino acids, nucleosides, nucleic acids and proteins at neutral pH. Our data indicated that NO‐AAF is a directly acting hepatocarcinogen in Sprague‐Dawley rats. NO‐AAF seems to be a directly acting mutagen, teratogen and probably a carcinogen of new prototype.
Kinetic and Structural Approaches to Enzyme Chemistry
Authors: Chang Gu‐Gang 
Published: June 2015

AbstractIn this review I summarize the research conducted in this enzymology laboratory. It includes purification, multiple forms, assay, activity‐staining, specificities, kinetics, modification, structure, mechanism, and regulation of the following enzymes: methionine S‐adenosyltransferase, aminoacyl‐tRNA synthetases, malic enzyme, alkaline phosphatase, acid phosphatase, and taxon‐specific crystallins.
Structural Characterization of Lens Crystallins and the Perspectives on the Evolution and Biosynthetic Applications of Enzymatic Crystallins
Authors: Chiou Shyh‐Horng 
Published: June 2015

AbstractThis account describes work in our laboratory on lens crystallins during the past decade. The major classes of crystallins are reviewed. A systematic and detailed analysis of the kinetic properties of two presumably structural proteins with stable enzymatic activities revealed subtle differences in kinetic mechanisms of these enzyme crystallins and their corresponding cellular enzymes. Bioorganic synthesis based on ϵ‐ and δ‐crystallins isolated from avian and reptilian lenses, two crystallins possessing lactate dehydrogenase and argininosuccinate lyase respectively, provides an efficient and practical tool for enantioselective synthesis of valuable organic intermediates. Understanding the crystallin diversity at the molecular and cellular levels constitutes a major goal of crystallin research, as it provides the framework to unravel the complex process underlying the evolution of lens crystallins in general and may provide insight into their biological significance.
Chemistry of Snake Neurotoxins and Future Perspectives
Authors: Yang C. C. 
Published: June 2015

AbstractA historical review on the study of snake neurotoxins is presented, with special emphasis on the author's contributions in unraveling the chemistry of one of the most lethal non‐enzymatic protein factors. Cobrotoxin, a postsynaptic neurotoxin isolated in a crystalline state from the venom of Taiwan cobra, binds specifically to the nicotinic acetylcholine receptors on the postsynaptic membrane and thus blocks the neuromuscular transmission. It is a small basic protein consisting of a single peptide chain of 62 aminoacid residues, crosslinked by four disulfide bonds. The disulfide bonds and Tyr‐25 which are buried in the molecule form a central core to maintain and stabilize the active conformation of the toxin. Selective and stepwise chemical modifications of cobrotoxin indicate that at least two cationic groups, an ϵ‐amino group of Lys‐47 and a guanidino group of Arg‐33, both of which are common to all known postsynaptic snake neurotoxins, held at a certain critical distance in the molecule, are functionally important for its neuromuscular blocking activity.Neurotoxins of another type exist in some common cobras or sea snakes. These presynaptic neurotoxins are basic phospholipase A2 (PLA2) per se or contain basic PLA2 as an indispensable part of their structures. Presynaptic PLA2 neurotoxins show both PLA2 activity and presynaptic neurotoxicity. Chemical modification of two highly potent presynaptic neurotoxins β1‐bungarotoxin and notexin was undertaken in the hope of elucidating the molecular features contributing to the biological activities of presynaptic PLA2 neurotoxins. Modification of tyrosine residues differentially influences the enzymatic activity and lethal toxicity of β1‐bungarotoxin and notexin, revealing that these toxins might possess two functional sites, one being responsible for the catalytic activity and the other for their pharmacological properties.
Development of a Novel Urine Alzheimer‐Associated Neuronal Thread Protein ELISA Kit and Its Potential Use in the Diagnosis of Alzheimer's Disease
Authors: Ma Lina , Wang Rong , Han Ying , Sheng Shuli , Zhu Jianan , Ji Zhijuan , Zhao Zhiwei , Cao Ziqing , Wang Peichang 
Published: June 2015

BackgroundAlzheimer's disease (AD) is an age‐related chronic degenerative disease that damages the nervous system. A noninvasive and simple method for early detection of AD is extremely important for the diagnosis and prognosis of AD. Thus, we aimed to develop an enzyme‐linked immunosorbent assay (ELISA) kit to detect urine Alzheimer‐associated neuronal thread protein (AD7C‐NTP), and to evaluate its clinical value for the diagnosis of AD.MethodsImmunogenic AD7C‐NTP peptide fragments were synthesized by the solid‐phase method and used for immunizing mice or rabbits to generate anti‐AD7C‐NTP antibodies. The urine AD7C‐NTP ELISA kit was then established; the generated mouse anti‐AD7C‐NTP antibody was used as a capture antibody, the biotin‐labeled rabbit anti‐AD7C‐NTP antibody was used as a detection antibody, and avidin labeled by horseradish peroxidase was used as a substrate. The first morning urine specimens of 121 AD patients and 118 age‐matched controls were collected, and the urine AD7C‐NTP levels were detected by the above ELISA kit.ResultsMouse and rabbit anti‐AD7C‐NTP antibody ELISA titer was found to be 1:8,000 and 1:32,000, respectively. A single band with a relative molecular mass of 41 kDa was found in human brain specimens by Western blot assay, which was identified as AD7C‐NTP antibody. The urine AD7C‐NTP concentration of the AD patients was higher than that of the age‐matched controls, the sensitivity was 89.3% and the specificity was 84.7%.ConclusionsOur study demonstrated that our newly developed urine AD7C‐NTP ELISA kit has suggested potential for diagnosing AD in a Chinese population, suggesting it may be a useful diagnostic kit for detecting early AD.
Evaluation of disease‐mediated therapeutic protein–drug interactions between an anti–interleukin‐6 monoclonal antibody (sirukumab) and cytochrome P450 activities in a phase 1 study in patients with rheumatoid arthritis using a cocktail approach
Authors: Zhuang Yanli , de Vries Dick E. , Xu Zhenhua , Marciniak Stanley J. , Chen Dion , Leon Francisco , Davis Hugh M. , Zhou Honghui 
Published: June 2015

AbstractThis therapeutic protein–drug interaction study evaluated the disease‐mediated effect of sirukumab (anti‐interleukin 6 [anti‐IL‐6] monoclonal antibody) on the pharmacokinetics of the cytochrome P450 (CYP) probe substrates midazolam (CYP3A), omeprazole (CYP2C19), warfarin (CYP2C9), and caffeine (CYP1A2) in patients with active rheumatoid arthritis (RA). Twelve patients with C‐reactive protein (CRP) ≥ 8.0 mg/L at screening received oral administration of a CYP probe cocktail consisting of 0.03 mg/kg midazolam, 10 mg warfarin + 10 mg vitamin K (equivalent to 5 mg S‐warfarin), 20 mg omeprazole, and 100 mg caffeine 1 week before and 1, 3, and 6 weeks after a single subcutaneous dose of 300 mg sirukumab. The results showed that the pharmacokinetics of midazolam, omeprazole, and S‐warfarin were nonequivalent before and after the administration of a single dose of 300 mg sirukumab. Area under the plasma concentration–time curve (AUC0–∞) for midazolam, omeprazole, and S‐warfarin was reduced by 30%−35%, 37%−45%, and 18%−19%, respectively, after sirukumab administration. Caffeine AUC0–∞ was increased by 20%−34% after sirukumab administration. The effect of sirukumab on CYP substrates was sustained for at least 6 weeks. No new adverse drug reactions related to the administration of sirukumab were observed in this study. These results suggest that sirukumab may reverse IL‐6‐mediated suppression of CYP3A, CYP2C9, and CYP2C19 activities in patients with active RA.
Defect pyrochlore oxides: as photocatalyst materials for environmental and energy applications ‐ a review
Authors: Jitta Raju Reddy , Gundeboina Ravi , Veldurthi Naveen Kumar , Guje Ravinder , Muga Vithal 
Published: June 2015

AbstractPhotocatalytic technology utilizing abundant solar light holds great promise to tackle many challenging environmental and energy issues. In recent years, various types of photocatalysts have been developed that are active for environmental purification and hydrogen production. Papers reporting preparation, characterization and photocatalytic testing of binary, ternary and quaternary compounds have been reviewed. The present review focuses on photocatalyst materials which adopt a defect pyrochlore structure. Starting with a brief introduction to semiconductor‐based photocatalysts for environmental clean‐up and hydrogen generation from water splitting, the development of high‐efficiency UV and visible light driven photocatalysts belonging to the defect pyrochlore family is reviewed. The review covers all the defect pyrochlore photocatalysts studied so far, and provides guidance to researchers in this area for further investigation of these materials. © 2015 Society of Chemical Industry
Oncologic outcome after local recurrence of chondrosarcoma: Analysis of prognostic factors
Authors: Kim Han‐Soo , Bindiganavile Srimanth S. , Han Ilkyu 
Published: June 2015

BackgroundLiterature on outcome after local recurrence (LR) in chondrosarcoma is scarce and better appreciation of prognostic factors is needed.Objectives(1) To evaluate post‐LR oncologic outcomes of disease‐specific survival and subsequent LR and (2) to identify prognostic factors for post‐LR oncologic outcomes.Patients and MethodsReview of 28 patients with locally recurrent chondrosarcoma from the original cohort of 150 patients, who were treated surgically with or without adjuvants between 1982 and 2011, was performed. Mean age was 46 years (range, 21–73) which included 20 males and 8 females with mean follow up of 8.4 ± 7.5 years (range, 1.2–31.0).ResultsPost‐LR survival at 5 years was 58.6 ± 10.3%. Age greater than 50 years (P = 0.011) and LR occurring within 1 year of primary surgery (P = 0.011) independently predicted poor survival. Seven patients suffered subsequent LR, which was significantly affected by surgical margin for LR (P = 0.038).ConclusionLong‐term survival of locally recurrent chondrosarcoma is achievable in a substantial number of patients. Older age at onset of LR and shorter interval from primary surgery to LR identifies high risk patients for poor post‐LR survival while, wide surgical margins at LR surgery reduces the risk of subsequent LR. J. Surg. Oncol. 2015 111:957–961. © 2015 Wiley Periodicals, Inc.
Prognostic factors and follow‐up strategy for superficial soft‐tissue sarcomas: Analysis of 622 surgically treated patients from the scandinavian sarcoma group register
Authors: Tsagozis Panagiotis , Bauer Henrik C. , Styring Emelie , Trovik Clement S. , Zaikova Olga , Brosjö Otte 
Published: June 2015

Background and ObjectivesOur study aimed to describe the clinical outcome of patients with superficial soft‐tissue sarcomas (SSTS), define prognostic factors and provide evidence for a rational surveillance scheme.MethodsData for 622 consecutive, surgically treated SSTS patients were retrieved from the Scandinavian Sarcoma Group Register. We assessed the rates of local recurrence (LR) and metastasis (M), as well as overall survival (OS), local recurrence free‐survival (LRFS) and metastasis‐free survival (MFS) of the cohort.ResultsThe incidence of LR and M was 9% and 12%, respectively. OS at 5 years was 79%, LRFS was 74% and MFS 76%. Factors that affected OS, LRFS, and MFS were tumor size and patient age. Additionally, tumor grade was an independent prognostic factor for LRFS. The majority of LR and M events were observed the first 2 years of follow‐up. Clear surgical margins were correlated to lower risk for LR. Selected patients benefited from adjuvant radiotherapy.ConclusionsSSTS have a favourable prognosis, which is mainly determined by tumour‐associated factors. Adequate surgical margins are important for local control, whereas radiotherapy has a secondary role. The data support current surveillance schemes, with a closer follow‐up the first 2 years after surgery. J. Surg. Oncol. 2015 111:951–956. © 2015 Wiley Periodicals, Inc.
Multi‐temporal Forest Cover Change and Forest Density Trend Detection in a Mediterranean Environment
Authors: Symeonakis Elias , Caccetta Peter A. , Wallace Jeremy F. , Arnau‐Rosalen Eva , Calvo‐Cases Adolfo , Koukoulas Sotirios 
Published: June 2015

AbstractThe loss of forests along with the various types of shrubs in the Mediterranean region is seen as an important driver of climate change and has been repeatedly related with the observed land degradation and desertification in the region. Nevertheless, the extent of woody perennial vegetation cover (WPVC) and its density remain largely unclear. Here, we apply a series of algorithms and methods operationally used in Australia for large‐scale WPVC mapping and monitoring and demonstrate their applicability in the Mediterranean region using a Spanish area as the trial site. Five Landsat TM and ETM+ images from various dates spanning 14 years are used to map changes in the extent of WPVC and to identify areas with a declining, stabilising or recovering trend. Results show that the applied methodology, which incorporates (i) pre‐processing of the Landsat imagery, (ii) a canonical variate analysis to spectrally discriminate between woody and non‐woody land cover types, (iii) a conditional probability network and (iv) spectral indices for mapping woody cover and density trend, is highly successful and well suited for use in Mediterranean environments. A rigorous accuracy assessment is undertaken producing overall accuracies above 97% for both woody and non‐woody cover types and all dates. Results also show that in the area of study, the majority of WPVC disturbances were due to forest fires, which represent the region's most frequent natural and anthropogenic disturbance. This raises significant concerns about the future of the area's WPVC. Regeneration compensated to some degree for the high disturbance rates. Copyright © 2015 John Wiley & Sons, Ltd.
Development of a discontinuous approach for modeling fluid flow in heterogeneous media using the numerical manifold method
Authors: Hu Mengsu , Wang Yuan , Rutqvist Jonny 
Published: June 2015

SummaryIn the numerical modeling of fluid flow in heterogeneous geological media, large material contrasts associated with complexly intersected material interfaces are challenging, not only related to mesh discretization but also for the accurate realization of the corresponding boundary constraints. To address these challenges, we developed a discontinuous approach for modeling fluid flow in heterogeneous media using the numerical manifold method (NMM) and the Lagrange multiplier method (LMM) for modeling boundary constraints. The advantages of NMM include meshing efficiency with fixed mathematical grids (covers), the convenience of increasing the approximation precision, and the high integration precision provided by simplex integration. In this discontinuous approach, the elements intersected by material interfaces are divided into different elements and linked together using the LMM. We derive and compare different forms of LMMs and arrive at a new LMM that is efficient in terms of not requiring additional Lagrange multiplier topology, yet stringently derived by physical principles, and accurate in numerical performance. To demonstrate the accuracy and efficiency of the NMM with the developed LMM for boundary constraints, we simulate a number of verification and demonstration examples, involving a Dirichlet boundary condition and dense and intersected material interfaces. Last, we applied the developed model for modeling fluid flow in heterogeneous media with several material zones containing a fault and an opening. We show that the developed discontinuous approach is very suitable for modeling fluid flow in strongly heterogeneous media with good accuracy for large material contrasts, complex Dirichlet boundary conditions, or complexly intersected material interfaces. Copyright © 2015 John Wiley & Sons, Ltd.