bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comprehensive Panel of Turn‐On Caspase Biosensors for Investigating Caspase Specificity and Caspase Activation Pathways
Authors: Shekhawat Sujan S. , Campbell Sean T. , Ghosh Indraneel 
Published: August 2011

AbstractCaspases play a central role in apoptosis, differentiation, and proliferation, and represent important therapeutic targets for treating cancer and inflammatory disorders. Toward the goal of developing new tools to probe caspase substrate cleavage specificity as well as to systematically interrogate caspase activation pathways, we have constructed and investigated a comprehensive panel of caspase biosensors with a split‐luciferase enabled bioluminescent read out. We first interrogated the panel of caspase biosensors for substrate cleavage specificity of caspase 1–10 in widely utilized in vitro translation systems, namely, rabbit reticulocyte lysate (RRL) and wheat germ extract (WGE). Commercial RRL was found to be unsuitable for investigating caspase specificity, owing to surprising levels of endogenous caspase activity, while specificity profiles of the caspase sensors in WGE agree very well with traditional peptide probes. The full panel of biosensors was utilized for studying caspase activation and inhibition in several mammalian cytosolic extracts, clearly demonstrating that they can be utilized to directly monitor activation or inhibition of procaspase 3/7. Furthermore, the complete panel of caspase biosensors also provided new insights into caspase activation pathways wherein we surprisingly discovered the activation of procaspase 3/7 by caspase 4/5.
Au on Nanosized NiO: A Cooperative Effect between Au and Nanosized NiO in the Base‐Free Alcohol Oxidation
Authors: Villa Alberto , Chan‐Thaw Carine E. , Veith Gabriel M. , More Karren L. , Ferri Davide , Prati Laura 
Published: August 2011

AbstractNanosized NiO has been synthesized and used as a support for polyvinyl alcohol‐protected Au nanoparticles. This catalytic system exhibits an extraordinary performance in the base‐free liquid phase oxidation of alcohols compared to the same Au supported on a commercial, micrometersized NiO. This enhancement in activity cannot be solely attributed to the improved basic properties of the support. A cooperative effect between Au nanoparticles and nanosized NiO is envisaged.
Mixed Conductivity, Nonstoichiometric Oxygen, and Oxygen Permeation Properties in Co‐Doped Sr3Ti2O7−δ
Authors: Nuansaeng Sirikanda , Yashima Masatomo , Matsuka Maki , Ishihara Tatsumi 
Published: August 2011

AbstractElectrical conductivity and oxygen permeation rates in Co‐doped Sr3Ti2O7−δ with Ruddesden–Popper type structures were investigated. The effects of metal dopants (M) in the Ti site of Sr3Ti2(M)O7−δ on the mixed conductivity were also studied. Doping of Sr3Ti2O7−δ with Co was found to be effective for improving the electrical conductivity as well as the oxygen permeation rate, which could be assigned to the increased oxygen vacancy concentration by doping Co3+ into Ti4+ sites. The nonstoichiometric oxygen of these oxides was measured by using a thermal gravimetric method. The creation of oxygen vacancies, which is compensated with Co3+ doping, leads to higher oxide ion conductivity. The oxygen permeation rate monotonously increased with increasing amounts of Co in the Ti site. Sr3Ti0.8Co1.2O7−δ exhibited high oxide ion conductivity and a large oxygen permeation rate. The highest oxygen permeation rate achieved a value of 2.02 cc min−1 cm−2 at 1273 K for Sr3Ti0.8Co1.2O7−δ. Neutron diffraction analysis and redox titration suggests that the oxygen diffusion occurs through oxygen vacancies in the perovskite block, but not through excess oxygen in the rock salt block.
Visual Scanometric Detection of DNA through Silver Enhancement Regulated by Gold‐Nanoparticle Aggregation with a Molecular Beacon as the Trigger
Authors: Ji Hanxu , Dong Haifeng , Yan Feng , Lei Jianping , Ding Ling , Gao Wenchao , Ju Huangxian 
Published: August 2011

AbstractA convenient and label‐free scanometric approach for DNA assay was designed by integrating a metal‐ion‐mediated conformational molecular beacon (MB) and silver‐signal amplification regulated by gold‐nanoparticle (AuNP) aggregation. The strategy was based on displacing the interaction between the target DNA sequence and a competitor Hg2+ ion with a link DNA sequence. In the absence of the target DNA sequence, a link DNA sequence interacted with the Hg2+ ions, thus forming an inactive cyclic conformation of the MB. This result led to the poor aggregation of polyadenosine‐functionalized AuNPs (A‐AuNP). In the presence of a target DNA sequence with a stronger affinity than that of the competitor, hybridization between the link DNA and target DNA sequences turned on the trigger. The polythymidine end of the resulting linear duplex structure could react with A‐AuNP, thus leading to a cross‐linking aggregation. This aggregation weakened AuNP‐catalyzed silver enhancement on a spot substrate. Further, by using scanometric detection, the concentration of the target DNA sequence could be conveniently read out within a linear range from 1.0 to 30 nM. Interestingly, in the same amount of Hg2+ ions, one‐base mismatched DNA showed only 22 % of the relative gray‐scale intensity for the target DNA sequence at the same concentration, thus indicating good specificity. The designed approach, with the help of the ion‐mediated conformational MB, was simple, cost effective, adaptable, and convenient and provided significant potential applications in clinical analysis.
Progress in Crystal Structure Prediction
Authors: Kendrick John , Leusen Frank J. J. , Neumann Marcus A. , van de Streek Jacco 
Published: August 2011

AbstractThe results of the application of a density functional theory method incorporating dispersive corrections in the 2010 crystal structure prediction blind test are reported. The method correctly predicted four out of the six experimental structures. Three of the four correct predictions were found to have the lowest lattice energy of any crystal structure for that molecule. The experimental crystal structures for all six compounds were found during the structure generation phase of the simulations, indicating that the tailor‐made force fields used for screening structures were valid and that the structure generation engine, which combines a Monte Carlo parallel tempering algorithm with an efficient lattice energy minimiser, was working effectively. For the three compounds for which the experimental crystal structures did not correspond to the lowest energy structures found, the method for calculating the lattice energy needs to be further refined or there may be other polymorphs that have not yet been found experimentally.
Anion‐Templated Supramolecular C3 Assembly for Efficient Inclusion of Charge‐Dispersed Anions into Hydrogen‐Bonded Networks
Authors: Užarević Krunoslav , Đilović Ivica , Bregović Nikola , Tomišić Vladislav , Matković‐Čalogović Dubravka , Cindrić Marina 
Published: August 2011

AbstractThe binding properties and conformational adaptability of a known nitrate/sulfate receptor N,N′‐3‐azapentane‐1,5‐bis[3‐(1‐aminoethylidene)‐6‐methyl‐3H‐pyran‐2,4‐dione] (L) toward various charge‐dispersed monoanions (HSO3−, ClO4−, IO4−, PF6−, and SbF6−) are considered. These anions template the folding of three HL+ species through a self‐assembly process into a new hollow supramolecular trication. During the self‐assembly, all strong hydrogen‐bond donors of the podand become coordinatively saturated by interactions with the oxo functionalities from other HL+ molecules. In that way, only the weak hydrogen‐bond‐donating groups in the exterior part of the receptor are accessible for anion binding. The investigated anions are accommodated in the hydrophobic pockets of the isomorphous hydrogen‐bonded frameworks, which serve as a basis for selective crystallization from the highly competitive anion/solvent systems. This behavior is discussed in terms of size and geometry of the anions as well as the receptor’s coordination capabilities to provide the most favorable surroundings for guest inclusion both in solution and in the solid state.
A Facile “Dispersion–Decomposition” Route to Metal Sulfide Nanocrystals
Authors: Zhuang Zhongbin , Lu Xiaotang , Peng Qing , Li Yadong 
Published: August 2011

AbstractIn this paper, we demonstrate a simple and general “dispersion–decomposition” approach to the synthesis of metal sulfide nanocrystals with the assistance of alkylthiol. This is a direct heating process without precursor injection. By using inorganic metal salts and alkylthiol as the raw materials, high‐quality Ag2S, Cu2S, PbS, Ni3S4, CdS, and ZnS nanocrystals were successfully synthesized. The mechanism study shows that the reaction undergoes two steps. A key intermediate compound, metal thiolate, is generated first. It melts and disperses into the solvent at a relatively low temperature, and then it decomposes into metal sulfide as a single precursor upon heating. This method avoids using toxic phosphine agent and injection during the reaction process. The size and shape of the nanocrystal can be also controlled by the concentration of the reactant and ligands. Furthermore, the optical properties and assembly of the nanocrystals have also been studied. This report provides a facile, direct‐heating “dispersion–decomposition” approach to synthesize metal sulfides nanocrystals that has potential for future large‐scale synthesis.
L‐Proline/CoCl2‐Catalyzed Highly Diastereo‐ and Enantioselective Direct Aldol Reactions
Authors: Karmakar Ananta , Maji Tapan , Wittmann Sebastian , Reiser Oliver 
Published: August 2011

AbstractThe CoCl2/L‐proline (1:2) system was found to be an excellent catalyst for direct aldol reactions. Excellent yields (up to 93 %) and a significant improvement in diastereoselectivity (anti/syn up to 45:1) as well as enantioselectivity (up to more than 99 % ee) compared with using proline as the sole catalyst were observed. This catalyst system was successfully applied to both cyclic and acyclic ketones in combination with aromatic and aliphatic aldehydes. In situ chelation of CoCl2 and proline (1:2) is proposed to promote the reaction through a six‐membered Zimmermann–Traxler type transition state involving the positioning of proline‐enamine and the aldehyde through chelation to CoII.
Total Synthesis of 7‐Ethyl‐10‐hydroxycamptothecin (SN38) and its Application to the Development of C18‐Functionalized Camptothecin Derivatives
Authors: Yao Yuan‐Shan , Liu Jia‐Li , Xi Jie , Miu Bukeyan , Liu Guai‐Sai , Wang Shaozhong , Meng Linghua , Yao Zhu‐Jun 
Published: August 2011

AbstractA new chemical synthesis of SN38, the active metabolite of the camptothecin prodrug irinotecan, has been achieved in 12 steps from simple, commercially available starting materials. A mild and efficient FeCl3‐catalyzed Friedländer condensation was successfully applied to construct the AB ring system. Functionalization of the C ring was accomplished by a vinylogous Mukaiyama reaction of an in situ generated N‐acyliminium intermediate with a silyl enol ether. An intramolecular oxa Diels–Alder reaction efficiently constructed the D and E rings in one step. Successive asymmetric dihydroxylation and I2‐based hemiacetal oxidation furnished the stereochemistry of SN38 with high enantiopurity. Utilizing the ABC‐ring intermediate and a functionalized silyl enol ether permitted the synthesis of a number of new C18‐functionalized SN38 derivatives. Several of the novel SN38 derivatives that bore a C10 methoxy group were found to exhibit comparable or more potent inhibitory activity against the proliferation of cancer cells relative to SN38.
Modeling solvent effects on chiroptical properties
Authors: Mennucci Benedetta , Cappelli Chiara , Cammi Roberto , Tomasi Jacopo 
Published: August 2011

AbstractIn this article, the most advanced extensions of solvation models to chiroptical properties of solvated systems will be reviewed. The main aspects determining the complex phenomenon of solvation will be first discussed in terms of the physical interactions beyond them and successively translated in a computational language introducing the specific models. A particular attention will be devoted to the family of solvation models which couple a quantum‐mechanical description of the molecular solute and a continuum description of the solvent. The theoretical analysis will be supported with examples of applications showing the potentialities of the models and their accuracy in capturing the essence of solvent effects on optically active molecules. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Mono‐ and bis‐quinidine organocatalysts in the asymmetric methanolysis of cis‐1,2,3,6‐tetrahydrophthalic anhydride: A conformational and mechanistic NMR study
Authors: Balzano Federica , Jumde Ravindra P. , Mandoli Alessandro , MASI SOFIA , PINI DARIO , UCCELLO‐BARRETTA GLORIA 
Published: August 2011

AbstractThe enantioselective organocatalytic methanolysis of cis‐1,2,3,6‐tetrahydrophthalic anhydride mediated by quinidine derivatives with pyridazine or anthraquinone core was investigated, carrying out a detailed nuclear magnetic resonance study of the conformational preferences of the alkaloid catalysts in the pure solvent and in the presence of the reaction substrates and products. No significant interaction between the meso‐anhydride and the alkaloid derivatives was detected. In contrast, evidence for a considerable influence of the alcohol reactant on the conformational state of some of the chiral organocatalysts could be obtained, which lends support to the hypothesis of general‐base catalysis mechanism, as opposed to the nuclephilic one. The catalytic properties of the studied derivatives showed no obvious correlation with their conformational prevalence in the resting state, suggesting that the alkaloid 9‐O substituent should have a more active role than merely enforcing the chiral fragments to adopt a preferential reactive conformation. A strong enantioselective interaction between the enantiomers of the hemiester product and the alkaloid derivatives was also observed, leading to the conclusion that in the actual reaction conditions a relatively large fraction of the latter is in the protonated form. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Comparison of mid‐infrared Fourier transform vibrational circular dichroism measurements with single and dual polarization modulations
Authors: Polavarapu Prasad L. , Shanmugam Ganesh 
Published: August 2011

AbstractFourier transform infrared vibrational circular dichroism (FTIR‐VCD) measurements have gone through major advances in the last decade. A major thrust in these advances was to find ways that can minimize the VCD spectral artifacts and obtain the VCD signals at enhanced signal quality. However, all these advances are not incorporated in FTIR‐VCD instruments manufactured by some commercial manufacturers. In this article, we compare the measurements obtained with single and dual polarization modulations to seek the attention of the users of single polarization modulation method in minimizing the artifacts in such measurements. We also report that the VCD spectrum of a home‐made collagen film can serve as a simple and convenient sample for routine verification of the correct functioning of the VCD spectrometers. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Stereodivergent synthesis of diastereoisomeric carba analogs of glycal‐derived vinyl epoxides: A new access to carbasugars
Authors: Frau Ileana , Bussolo Valeria DI , Favero Lucilla , Pineschi Mauro , Crotti Paolo 
Published: August 2011

AbstractA convenient method for the stereoselective synthesis of diasteroisomeric vinyl epoxides (−)‐2α and (−)‐2β, the carba analogs of D‐galactal and D‐allal‐derived vinyl epoxides 1αand 1β, has been elaborated starting from tri‐O‐acetyl‐D‐glucal. The key step of this synthesis is an application of the known Claisen thermal rearrangement of a glucal derivative, the vinyl allyl ether (+)‐3b, which allows to switch the glycal structure into the corresponding carba analog scaffold. Epoxides (−)‐2α and (−)‐2β derive from the same synthetic intermediate, the trans diol (+)‐5. Chirality, 2011. © 2011 Wiley‐Liss, Inc.
Actin‐depolymerizing factor homology domain: A conserved fold performing diverse roles in cytoskeletal dynamics
Authors: Poukkula Minna , Kremneva Elena , Serlachius Martina , Lappalainen Pekka 
Published: August 2011

AbstractActin filaments form contractile and protrusive structures that play central roles in many processes such as cell migration, morphogenesis, endocytosis, and cytokinesis. During these processes, the dynamics of the actin filaments are precisely regulated by a large array of actin‐binding proteins. The actin‐depolymerizing factor homology (ADF‐H) domain is a structurally conserved protein motif, which promotes cytoskeletal dynamics by interacting with monomeric and/or filamentous actin, and with the Arp2/3 complex. Despite their structural homology, the five classes of ADF‐H domain proteins display distinct biochemical activities and cellular roles, only parts of which are currently understood. ADF/cofilin promotes disassembly of aged actin filaments, whereas twinfilin inhibits actin filament assembly via sequestering actin monomers and interacting with filament barbed ends. GMF does not interact with actin, but instead binds Arp2/3 complex and promotes dissociation of Arp2/3‐mediated filament branches. Abp1 and drebrin are multidomain proteins that interact with actin filaments and regulate the activities of other proteins during various actin‐dependent processes. The exact function of coactosin is currently incompletely understood. In this review article, we discuss the biochemical functions, cellular roles, and regulation of the five groups of ADF‐H domain proteins. © 2011 Wiley‐Liss, Inc.
Low expression and secretion of circulating soluble CTLA‐4 in peripheral blood mononuclear cells and sera from type 1 diabetic children
Authors: Rydén Anna , Bolmeson Caroline , Jonson Carl‐Oscar , Cilio Corrado M. , Faresjö Maria 
Published: August 2011

AbstractBackgroundHigh levels of soluble cytotoxic T‐lymphocyte antigen 4 (soluble CTLA‐4), an alternative splice form of the regulatory T‐cell (Treg) associated CTLA‐4 gene, have been associated with type 1 diabetes (T1D) and other autoimmune diseases, such as Grave's disease and myasthenia gravis. At the same time, studies have shown soluble CTLA‐4 to inhibit T‐cell activation through B7 binding. This study aimed to investigate the role of soluble CTLA‐4 in relation to full‐length CTLA‐4 and other Treg‐associated markers in T1D children and in individuals with high or low risk of developing the disease.MethodsT1D children were studied at 4 days, 1 and 2 years after diagnosis in comparison to individuals with high or low risk of developing the disease. Isolated peripheral blood mononuclear cells were stimulated with the T1D‐associated glutamic acid decarboxylase 65 and phytohaemagglutinin. Subsequently, soluble CTLA‐4, full‐length CTLA‐4, FOXP3 and TGF‐β mRNA transcription were quantified and protein concentrations of soluble CTLA‐4 were measured in culture supernatant and sera.Results and ConclusionsLow protein concentrations of circulating soluble CTLA‐4 and a positive correlation between soluble CTLA‐4 mRNA and protein were seen in T1D, in parallel with a negative correlation in healthy subjects. Further, low levels of mitogen‐induced soluble CTLA‐4 were accompanied by low C‐peptide levels. Interestingly, low mitogen‐induced soluble CTLA‐4 mRNA and low TGF‐β mRNA expression were seen in high risk individuals, suggesting an alteration in activation and down‐regulating immune mechanisms during the pre‐diabetic phase. Copyright © 2011 John Wiley & Sons, Ltd.
Skin fibroblasts as a tool for identifying the risk of nephropathy in the type 1 diabetic population
Authors: Millioni Renato , Puricelli Lucia , Iori Elisabetta , Trevisan Roberto , Tessari Paolo 
Published: August 2011

AbstractHuman fibroblasts in culture have been employed as an in vitro system to investigate some pathophysiological mechanisms of diabetes mellitus also associated with the development of diabetic nephropathy. In fact, there is increasing evidence that genetic factors either convey the risk of, or protect from, diabetic nephropathy and that the expression profiles and/or the behaviour of the cultured skin fibroblasts from type 1 diabetic patients could reflect these genetic influences. On the other hand, alterations could be attributable not only to changes in DNA sequence, but also to epigenetic factors. Our aim is to make a critical overview of the studies involving primary cultures of skin fibroblasts as tools to investigate the pathophysiology of diabetic nephropathy performed until now in this area. Cultured skin fibroblasts could be useful not only for the identification of patients at risk of developing diabetic renal disease, but also for a better understanding of the complex multifactorial mechanisms leading to the long‐term complications in diabetes. Copyright © 2011 John Wiley & Sons, Ltd.
Strategies for insulin initiation: insights from the French LIGHT observational study
Authors: Vergès Bruno , Brun Jean Marcel , Tawil Camille , Alexandre Bertrand , Kerlan Véronique 
Published: August 2011

AbstractBackgroundThe progressive nature of type 2 diabetes necessitates exogenous insulin use for most patients; basal insulin plus oral anti‐diabetes drugs (OADs) is a well‐validated way to facilitate insulin initiation. The primary aim of this study was to explore insulin initiation strategies and outcomes for patients using insulin detemir or glargine plus oral anti‐diabetes drugs.MethodsLIGHT was a 3‐month, longitudinal observational study conducted across 761 French centres in insulin‐naïve type 2 diabetes patients managed under routine clinical care conditions, in either primary or secondary care. Endpoints included changes in HbA1c, fasting plasma glucose (FPG), rate of hypoglycaemia, weight, and adverse events.ResultsMost physicians initiated a basal analogue to improve glycaemic control (97%), with many delaying beginning treatment for several months (9 ± 9.0 months for general practitioners, 10.2 ± 16.2 months for specialists). Most patients continued oral anti‐diabetes drug therapy (95%) and lifestyle measures (92%), with 2–3 blood glucose readings per day and follow‐up telephone calls for dose optimization. Mean change in HbA1c from baseline was − 1.3%, and − 3.1 mmol/L for fasting plasma glucose (both p < 0.0001). Hypoglycaemia increased from 1.4 to 5.6 events/patient/year (p < 0.0001), and weight decreased on average by 0.5 kg with detemir, with no change in glargine. Most patients (93%) reported being satisfied or very satisfied with their insulin.ConclusionsInsulin initiation with detemir or glargine can be successfully managed in both primary and secondary care; the benefits of basal analogues (once‐daily dosing, low rates of hypoglycaemia compared with neutral protamine Hagedorn) may have contributed to patient acceptance of the regimen. Copyright © 2012 John Wiley & Sons, Ltd.