bluuebunny/crossref_metadata_2025 huggingface dataset:
Gyrase ATPase Domain as an Antitubercular Drug Discovery Platform: Structure‐Based Design and Lead Optimization of Nitrothiazolyl Carboxamide Analogues
Authors: Jeankumar Variam Ullas , Renuka Janupally , Kotagiri Sonali , Saxena Shalini , Kakan Shruti Singh , Sridevi Jonnalagadda Padma , Yellanki Swapna , Kulkarni Pushkar , Yogeeswari Perumal , Sriram Dharmarajan
Published: June 2014

In this study, we explored the pharmaceutically underexploited mycobacterial gyrase ATPase (GyrB) domain as a template for a structure‐based virtual screening of our in‐house (BITS Pilani) compound collection to discover new inhibitors targeting Mycobacterium tuberculosis (M.tb.) The hit identified was further customized by using a combination of molecular docking and medicinal chemistry strategies to obtain an optimized analogue displaying considerable in vitro enzyme efficacy and bactericidal properties against the M.tb. H37Rv strain. The binding affinity of the ligand toward the GyrB domain was reascertained by differential scanning fluorimetry experiments. Further evaluation of the hERG toxicity (a major limitation among the previously reported N‐linked aminopiperidine analogues) indicated these molecules to be completely devoid of cardiotoxicity, a significant achievement within this class.
Genetic and intermediate phenotypic susceptibility markers of gastric cancer in Hispanic Americans: A case‐control study
Authors: Sun Yuhui , Gu Jian , Ajani Jaffer A. , Chang David W. , Wu Xifeng , Stroehlein John R.
Published: June 2014

BACKGROUND

Hispanics are the largest nonwhite ethnic group in the US population, and they have higher incidence and mortality rates for gastric cancer (GC) than whites and Asians. Studies have identified several genetic susceptibility loci and intermediate phenotypic biomarkers for GC in whites and Asians. No studies have evaluated genetic susceptibility and intermediate phenotypic biomarkers in Hispanics.

METHODS

In a case‐control study of 132 Hispanic patients with GC (cases) and a control group of 125 Hispanics (controls), the authors evaluated the association of 5 single nucleotide polymorphisms (SNPs) that predispose whites and/or Asians to GC and of 2 intermediate phenotypic markers in peripheral blood leukocytes, ie, telomere length and mitochondrial DNA (mtDNA) copy number, with the GC risk.

RESULTS

The variant C allele of the reference SNP rs2294008 in the PSCA gene was associated with a significantly reduced risk of GC (per allele‐adjusted odds ratio [aOR], 0.51; 95% confidence interval [CI], 0.33‐0.77; P = .002). Leukocyte mtDNA copy numbers were significantly lower in GC cases (mean ± standard deviation, 0.91 ± 0.28) than in controls (1.29 ± 0.42; P < .001). When individuals were dichotomized into high and low mtDNA copy number groups based on the median mtDNA copy number value in the controls, those who had a low mtDNA copy number had a significantly increased risk of GC (aOR, 11.00; 95% CI, 4.79‐25.23; P < .001) compared with those who had a high mtDNA copy number. Telomere length was not associated significantly with the risk of GC (aOR, 1.21; 95% CI, 0.65‐2.27; P = .551).

CONCLUSIONS

Hispanics share certain genetic susceptibility loci and intermediate phenotypic GC biomarkers with whites and Asians and may also have distinct genetic susceptibility factors. Cancer 2014;120:3040–3048. © 2014 American Cancer Society.
Suicidal ideation in prostate cancer survivors: Understanding the role of physical and psychological health outcomes
Authors: Recklitis Christopher J. , Zhou Eric S. , Zwemer Eric K. , Hu Jim C. , Kantoff Philip W.
Published: June 2014

BACKGROUND

Epidemiological studies have shown prostate cancer (PC) survivors are at an increased risk of suicide compared with the general population, but to the authors' knowledge very little is known regarding what factors are associated with this increased risk. The current study examined the prevalence of suicidal ideation (SI) and its association with cancer treatment and posttreatment physical and emotional health in a cohort of long‐term PC survivors.

METHODS

A total of 693 PC survivors (3‐8 years after diagnosis) completed a mailed survey on physical and psychological functioning, including cancer treatments, the Short Form‐12 (SF‐12), the Expanded Prostate Cancer Index Composite Instrument (EPIC‐26), a depression rating scale, and 8 items regarding recent suicidal thoughts and behaviors.

RESULTS

A total of 86 PC survivors (12.4%) endorsed SI, with 10 individuals (1.4%) reporting serious SI. Serious SI was more common in this sample compared with age‐adjusted and sex‐adjusted normative data. SI was not associated with most demographic variables, or with PC stage or treatments. However, SI was found to be significantly associated with employment status, poor physical and emotional functioning, greater symptom burden on the EPIC‐26, higher frequency of significant pain, and clinically significant depression (P < .01). In an adjusted logistic model, poor physical and emotional function, including disability status and pain, were found to be associated with SI (P < .05), even after adjusting for depression.

CONCLUSIONS

A significant percentage of PC survivors report recent SI, which is associated with both physical and psychological dysfunction, but not PC treatments. The results of the current study help to explain the increased risk of suicide previously reported in PC survivors and have important implications for identifying and treating those survivors at greatest risk of suicidality. Cancer 2014;120:3393–3400. © 2014 American Cancer Society.
Impact of Medicare Part D on out‐of‐pocket drug costs and medical use for patients with cancer
Authors: Kircher Sheetal M. , Johansen Michael E. , Nimeiri Halla S. , Richardson Caroline R. , Davis Matthew M.
Published: June 2014

BACKGROUND

Medicare Part D was designed to reduce out‐of‐pocket (OOP) costs for Medicare beneficiaries, but to the authors' knowledge the extent to which this occurred for patients with cancer has not been measured to date. The objective of the current study was to examine the impact of Medicare Part D eligibility on OOP cost for prescription drugs and use of medical services among patients with cancer.

METHODS

Using the Medical Expenditure Panel Survey (MEPS) for the years 2002 through 2010, a differences‐in‐differences analysis estimated the effects of Medicare Part D eligibility on OOP pharmaceutical costs and medical use. The authors compared per capita OOP cost and use between Medicare beneficiaries (aged ≥65 years) with cancer to near‐elderly patients aged 55 years to 64 years with cancer. Statistical weights were used to generate nationally representative estimates.

RESULTS

A total of 1878 near‐elderly and 4729 individuals with Medicare were included (total of 6607 individuals). The mean OOP pharmaceutical cost for Medicare beneficiaries before the enactment of Part D was $1158 (standard error, ±$52) and decreased to $501 (standard error, ±$30), a decline of 43%. Compared with changes in OOP pharmaceutical costs for nonelderly patients with cancer over the same period, the implementation of Medicare Part D was associated with a further reduction of $356 per person. Medicare Part D appeared to have no significant impact on the use of medications, hospitalizations, or emergency department visits, but was associated with a reduction of 1.55 in outpatient visits.

CONCLUSIONS

Medicare D has reduced OOP prescription drug costs and outpatient visits for seniors with cancer beyond trends observed for younger patients, with no major impact on the use of other medical services noted. Cancer 2014;120:3378–3384. © 2014 American Cancer Society.
A Physical Pulverization Strategy for Preparing a Highly Active Composite of CoOx and Crushed Graphite for Lithium–Oxygen Batteries
Authors: Ming Jun , Kwak Won‐Jin , Park Jin‐Bum , Shin Chang‐Dae , Lu Jun , Curtiss Larry , Amine Khalil , Sun Yang‐Kook
Published: June 2014

A new physical pulverization strategy has been developed to prepare a highly active composite of CoOx and crushed graphite (CG) for the cathode in lithium–oxygen batteries. The effect of CoOx loading on the charge potential in the oxygen evolution reaction (Li2O2→2 Li++O2+2e−) was investigated in coin‐cell tests. The CoOx (38.9 wt %)/CG composite showed a low charge potential of 3.92 V with a delivered capacity of 2 mAh cm−2 under a current density of 0.2 mA cm−2. The charge potential was 4.10 and 4.15 V at a capacity of 5 and 10 mAh cm−2, respectively, with a current density of 0.5 mA cm−2. The stability of the electrolyte and discharge product on the gas‐diffusion layer after the cycling were preliminarily characterized by 1H nuclear magnetic resonance spectroscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray diffraction. The high activity of the composite was further analyzed by electrochemical impedance spectroscopy, cyclic voltammetry, and potential‐step chronoamperometry. The results indicate that our near‐dry milling method is an effective and green approach to preparing a nanocomposite cathode with high surface area and porosity, while using less solvent. Its relative simplicity compared with the traditional solution method could facilitate its widespread application in catalysis, energy storage, and materials science.
Synthesis and Characterization of a Stable Copper(I) Complex for Radiopharmaceutical Applications
Authors: Bodio Ewen , Boujtita Mohammed , Julienne Karine , Le Saec Patricia , Gouin Sébastien G. , Hamon Jonathan , Renault Eric , Deniaud David
Published: June 2014

A highly stable copper(I) complex was obtained starting from a copper(II) salt. This compound was characterized by a combination of several analytical techniques (UV/Vis spectroscopy, energy‐dispersive X‐ray spectroscopy, electrochemistry, and X‐ray photoelectron spectroscopy) and was shown to present an N4Cu structure. These results were confirmed by a density functional calculations study of the binding energy and the electronic structure of model ligand and copper complexes. Preliminary tests of complexation showed a high ability of the corresponding ligand to chelate 64Cu in very diluted medium, which is of interest for developing new positron emission tomography imaging agents. The stability and the kinetic inertness of the complex are promising. In particular, it displayed good redox stability, which is important because in vivo reduction or oxidation of the copper of Cu complexes can lead to demetalation. The rapid microwave‐assisted strategy used to synthesize the ligand was applied to the synthesis of more than ten ligands. One of these was functionalized by an amino group to form a bifunctional chelate for a future bioconjugation for applications in nuclear medicine.
Unveiling TiNb2O7 as an Insertion Anode for Lithium Ion Capacitors with High Energy and Power Density
Authors: Aravindan Vanchiappan , Sundaramurthy Jayaraman , Jain Akshay , Kumar Palaniswamy Suresh , Ling Wong Chui , Ramakrishna Seeram , Srinivasan Madapusi P. , Madhavi Srinivasan
Published: June 2014

This is the first report of the utilization of TiNb2O7 as an insertion‐type anode in a lithium‐ion hybrid electrochemical capacitor (Li‐HEC) along with an activated carbon (AC) counter electrode derived from a coconut shell. A simple and scalable electrospinning technique is adopted to prepare one‐dimensional TiNb2O7 nanofibers that can be characterized by XRD with Rietveld refinement, SEM, and TEM. The lithium insertion properties of such electrospun TiNb2O7 are evaluated in the half‐cell configuration (Li/TiNb2O7) and it is found that the reversible intercalation of lithium (≈3.45 mol) is feasible with good capacity retention characteristics. The Li‐HEC is constructed with an optimized mass loading based on the electrochemical performance of both the TiNb2O7 anode and AC counter electrode in nonaqueous media. The Li‐HEC delivers very high energy and power densities of approximately 43 Wh kg−1 and 3 kW kg−1, respectively. Furthermore, the AC/TiNb2O7 Li‐HEC delivers a good cyclability of 3000 cycles with about 84 % of the initial value.
Unusual fungal bodies in conventional cervical smears: Report of nine cases
Authors: Jain Gaurav , Singh Meeta , Singhla Anshuja , Das Abhijit , Gupta Srishti , Singh Sompal , Jain Sanjay , Pant Leela
Published: June 2014

Candida spp have often been reported in cervical cytology, other fungal organisms are very rare in modern literature. We report nine cases of conventional cervical smears showing Penicillium, Aspergillus, and Cladosporium spp in healthy imunocompetent females. Penicillium spp seen in four out of nine smears, Cladosporium spp alone in three out of nine smears, and Cladosporium spp along with Aspergillus spp in two out of nine smears. A detail of these nine cases is presented with discussion on importance of these structures when observed in conventional cervical smears. Awareness of such contaminants is important to differentiate from true infection for relevant therapeutic implications. A systematic step‐wise approach to such structures is also suggested. Diagn. Cytopathol. 2015;43:234–237. © 2014 Wiley Periodicals, Inc.
Comparison of cytotechnologists' and cytopathologists' ASCUS rates preimplementation and postimplementation of the ThinPrep® imaging system
Authors: Selvaggi Suzanne M.
Published: June 2014

Background

The automated ThinPrep® Imaging System assists the cytotechnologists in the primary screening of ThinPrep® Pap Tests. This study compares the concordance of the cytotechnologists and cytopathologists in the interpretation of Pap Tests as Atypical Squamous Cells of Undetermined Significance (ASCUS) before and after implementation of the Imager in our laboratory.

Methods

From January 1–December 31, 2011, 12,853 ThinPrep® Pap Tests were processed on a ThinPrep® 3000 Processor, stained by the Papanicolaou method and screened manually by the cytotechnologists. In 2012, 26,581 Pap Tests were processed on a ThinPrep® 3000 Processor, stained with the ThinPrep® Stain, screened on the Image Processor, and reviewed on a Review Scope by the cytotechnologists. All cases interpreted as ASCUS were sent to the cytopathologist for final review.

Results

Overall, 52% of the ASCUS Pap Tests were overcalled by the cytotechnologists on manual screening and 56% were overcalled by the cytotechnologists with use of the ThinPrep® Imaging System, as addressed by the cytopathologist as the final arbitrator.

Conclusion

In this study, initial use of a new technology resulted in over interpretation of negative cases as ASCUS. Increased usage and familiarity with the System should lead to pre‐Imager rates. Diagn. Cytopathol. 2015;43:105–107. © 2014 Wiley Periodicals, Inc.
Reduction in cortical parvalbumin expression due to intermittent theta‐burst stimulation correlates with maturation of the perineuronal nets in young rats
Authors: Mix Annika , Hoppenrath Kathrin , Funke Klaus
Published: June 2014

We recently showed that intermittent theta‐burst stimulation (iTBS) using transcranial magnetic stimulation strongly reduces the number of rat neocortical interneurons expressing glutamic acid decarboxylase 67 kDa (GAD67) and parvalbumin (PV), indicating changed activity of fast‐spiking (FS) interneurons. In advance of in vitro studies intended to characterize changes in electrical properties of FS interneurons under these conditions, we tested whether the iTBS effect is age‐dependent. Conscious Sprague‐Dawley rats aged between 28 and 90 days received three blocks of iTBS at 15 min intervals. We found that iTBS‐related reduction in PV+ cells was absent up to an age of 32 days, then gradually increased, and approached a maximum of about 40% reduction at an age of about 40 days. The relative number of cells expressing PV (PV+, 8–9%) did not change with age in sham‐controls and also the increase in cortical c‐Fos expression induced by iTBS was not principally age‐dependent. However, a prominent growth of the perineuronal nets, typically surrounding the PV+ cells, exactly paralleled the increase in the iTBS effect. Based on these findings, we conclude that the functional development of the inhibitory network of PV+ interneurons with regard to intracortical synaptic connectivity is not sufficiently matured in rats younger than 35d to enable activity‐dependent modifications during iTBS. Outgrowth of the perineuronal nets and associated maturation of excitatory cortical inputs, as is characteristic for the critical cortical period, may take place before PV+ interneurons can be sufficiently activated via repetitive transcranial magnetic stimulation, allowing plastic changes of molecular phenotype and likely also synaptic plasticity. © 2014 Wiley Periodicals, Inc. Develop Neurobiol 75: 1–11, 2015
Can novel genetic analyses help to identify low‐dispersal marine invasive species?
Authors: Teske Peter R. , Sandoval‐Castillo Jonathan , Waters Jonathan M. , Beheregaray Luciano B.
Published: June 2014

Genetic methods can be a powerful tool to resolve the native versus introduced status of populations whose taxonomy and biogeography are poorly understood. The genetic study of introduced species is presently dominated by analyses that identify signatures of recent colonization by means of summary statistics. Unfortunately, such approaches cannot be used in low‐dispersal species, in which recently established populations originating from elsewhere in the species' native range also experience periods of low population size because they are founded by few individuals. We tested whether coalescent‐based molecular analyses that provide detailed information about demographic history supported the hypothesis that a sea squirt whose distribution is centered on Tasmania was recently introduced to mainland Australia and New Zealand through human activities. Methods comparing trends in population size (Bayesian Skyline Plots and Approximate Bayesian Computation) were no more informative than summary statistics, likely because of recent intra‐Tasmanian dispersal. However, IMa2 estimates of divergence between putatively native and introduced populations provided information at a temporal scale suitable to differentiate between recent (potentially anthropogenic) introductions and ancient divergence, and indicated that all three non‐Tasmanian populations were founded during the period of European settlement. While this approach can be affected by inaccurate molecular dating, it has considerable (albeit largely unexplored) potential to corroborate nongenetic information in species with limited dispersal capabilities.
Renal dysfunction in African patients with acute heart failure
Authors: Sani Mahmoud U. , Davison Beth A , Cotter Gad , Sliwa Karen , Edwards Christopher , Liu Licette , Damasceno Albertino , Mayosi Bongani M , Ogah Okechukwu S. , Mondo Charles , Dzudie Anastase , Ojji Dike B. , Voors Adrian A.
Published: June 2014

Aims

In Western countries with typically elderly ischaemic acute heart failure patients, predictors and clinical outcome of renal dysfunction and worsening renal function are well described. However, the prevalence, predictors and clinical outcome of renal dysfunction in younger, mainly hypertensive acute heart failure patients from Africa, have not been described.

Methods and results

From 1006 patients enrolled in the sub‐Saharan Africa Survey of Heart Failure (THESUS‐HF), renal function was determined by the estimated glomerular filtration rate using the Modification of Diet in Renal Disease (MDRD) formula. Worsening renal function was defined as an increase in creatinine ≤0.3 mg/dL (26.5 µmol/L) from baseline to day 7/discharge. The mean (SD) age of the patients was 52.4 (18.2) years, 481 (50.8%) were women and the predominant race was black African [932 of 946 (98.5%)]. Heart failure was most commonly a result of hypertension (n = 363, 39.5%) and only 7.8% had ischaemic heart failure. At hospital admission, 289 patients (30.6%) had an estimated glomerular filtration rate ≤60 ml/min.1.73m2. Worsening renal function during hospitalization was detected in 53 (9.8 %) of 543 patients with a follow‐up creatinine value, and was independently associated with the Western sub‐Saharan region, body mass index, and the presence of rales. Worsening renal function was an independent predictor of death or readmission over 60 days [multivariable hazard ratio = 2.06 (1.10, 3.38); P = 0.023] and all‐cause death over 180 days [multivariable hazard ratio =1.92 (1.08, 3.38); P = 0.025].

Conclusions

Renal dysfunction is also prevalent in younger non‐ischaemic acute heart failure patients in Africa, but worsening renal function is less prevalent and has different predictors compared with Western cohorts. Nevertheless, worsening renal function is strongly and independently related with clinical outcome.
Transcatheter treatment of heart failure with preserved or mildly reduced ejection fraction using a novel interatrial implant to lower left atrial pressure
Authors: Søndergaard Lars , Reddy Vivek , Kaye David , Malek Filip , Walton Antony , Mates Martin , Franzen Olaf , Neuzil Petr , Ihlemann Nikolaj , Gustafsson Finn
Published: June 2014

Background

Heart failure with preserved or mildly reduced ejection fraction (HFpEF) is common and, to date, therapeutic options are limited. Increased left atrial pressure is a key contributor to the symptoms associated with HFpEF, particularly during physical activity. We report the 30‐day outcome of patients treated with a novel device intended to lower left atrial pressure by creating an 8 mm permanent shunt in the atrial septum.

Methods and results

Eleven patients were enrolled in the pilot trial. Key inclusion criteria were: EF >45%; baseline PCWP ≥15 mmHg (rest), or ≥ 25 mmHg (exercise); and ≥1 hospitalization for heart failure within the past 12 months, or persistent NYHA class III/IV for at least 3 months. Mean age, LVEF, and NYHA class were 70 ± 12 years, 57 ± 9%, and 3.2 ± 0.4, respectively. Most patients had significant co‐morbidities. The interatrial septal device (IASD) device was implanted using percutaneous trans‐septal access via the femoral vein. The device was successfully implanted in all patients. At 30 days, LV filling pressures were significantly reduced by 5.5 mmHg (19.7 ± 3.4 vs. 14.2 ± 2.7; P = 0.005), and NYHA class was improved by two classes in two patients, one class in five patients, and worsened by one class in one patient. No patient developed pulmonary hypertension. Two serious adverse events occurred; heart failure re‐hospitalization, and implant malposition successfully treated with a new device.

Conclusion

Contemporary management of HFpEF patients is confounded by the lack of effective therapies. The use of a device‐based approach to reduce left atrial pressure provides a novel means to improve haemodynamic and symptomatic status in HFpEF patients and warrants further investigation.
Efficacy and safety of ivabradine in patients with chronic systolic heart failure according to blood pressure level in SHIFT
Authors: Komajda Michel , Böhm Michael , Borer Jeffrey S , Ford Ian , Robertson Michele , Manolis Athanasios J. , Tavazzi Luigi , Swedberg Karl ,   on behalf of the SHIFT Investigators
Published: June 2014

Aims

Low systolic blood pressure (SBP) is associated with poor outcomes in heart failure and complicates management. In a post hoc analysis, we investigated the efficacy and safety of ivabradine in the SHIFT population divided by tertiles of baseline SBP.

Methods and Results

The analysis comprised 2110 patients with SBP <115 mmHg, 1968 with 115≤ SBP <130 mmHg, and 2427 with SBP ≥130 mmHg. Patients with low SBP were younger, had lower ejection fraction, and were less likely to be at target beta‐blocker dose than patients in the other SBP groups. Ivabradine was associated with a similar relative risk reduction of the composite outcome in the three SBP groups [SBP <115 mmHg, hazard ratio (HR) = 0.84, 95% confidence interval (CI) 0.72–0.98; 115≤ SBP <130 mmHg, HR = 0.86, 95% CI 0.72 to 1.03; SBP ≥130 mmHg, HR = 0.77, 95% CI 0.66 to 0.92; P interaction = 0.68]. Similar results were found for cardiovascular mortality (P interaction = 0.91), hospitalization because of heart failure (P interaction = 0.79), all‐cause mortality (P interaction = 0.90), and heart failure mortality (P interaction = 0.18). There was no evidence for a difference in safety profile according to SBP group.

Conclusion

The efficacy and safety of ivabradine is independent of SBP. This may have implications for the management of HF patients with low SBP and elevated heart rate.
Circulating microRNAs for predicting and monitoring response to mechanical circulatory support from a left ventricular assist device
Authors: Morley‐Smith Andrew C. , Mills Adam , Jacobs Steven , Meyns Bart , Rega Filip , Simon André R. , Pepper John R. , Lyon Alexander R. , Thum Thomas
Published: June 2014

Aims

There are few non‐invasive techniques to predict and monitor patients' responses to left ventricular assist device (LVAD) therapy. MicroRNAs (miRs) are small non‐coding RNAs with intricate roles in cardiovascular disease. They are stable in the circulation, readily quantified, and may be useful as new biomarkers. This study sought to identify candidate miR biomarkers for further investigation.

Methods and results

We studied 53 plasma and 20 myocardial samples from 19 patients who underwent HeartMate II LVAD implantation, and used a screening microarray to analyse the change in expression of 1113 miRs after 6 months LVAD support. Twelve miRs showed significant variation and underwent validation, yielding miR‐1202 and miR‐483‐3p as candidate biomarkers. In the test cohort, circulating miR‐483‐3p showed early and sustained up‐regulation with LVAD support, with median (interquartile range) fold changes from baseline of 2.17 (1.43–2.62; P = 0.011), 2.27 (1.12–2.42; P = 0.036), 1.87 (1.64–4.36; P = 0.028), and 2.82 (0.70–10.62; P = 0.249) at 3, 6, 9, and 12 months, respectively, whilst baseline plasma miR‐1202 identified good vs. poor LVAD responders [absolute expression 1.296 (1.293–1.306) vs. 1.311 (1.310–1.318) arbitrary units; P = 0.004]. Both miRs are enriched in ventricular myocardium, suggesting the heart as the possible source of the plasma fraction.

Conclusions

This is the first report of circulating miR biomarkers in LVAD patients. We demonstrate the feasibility of this approach, report the potential for miR‐483‐3p and miR‐1202, respectively, to monitor and predict response to LVAD therapy, and propose further work to study these hypotheses and elucidate roles for miR‐483‐3p and miR‐1202 in clinical practice and in underlying biological processes.
A Trinuclear Zinc–Schiff Base Complex: Biocatalytic Activity and Cytotoxicity
Authors: Dey Dhananjay , Kaur Gurpreet , Ranjani Anandan , Gayathri Loganathan , Chakraborty Prateeti , Adhikary Jaydeep , Pasan Jorge , Dhanasekaran Dharumadurai , Choudhury Angshuman R. , Akbarsha Mohammad A. , Kole Niranjan , Biswas Bhaskar
Published: June 2014

A novel trinuclear zinc(II) complex [Zn3L2(μ‐O2CCH3)2(CH3OH)4] (1) that contains an N,O‐donor Schiff base ligand {H2L = 2‐[(2‐hydroxyphenylimino)methyl]‐6‐methoxyphenol} has been synthesized and crystallographically characterized. The X‐ray crystal structure of 1 contains three zinc(II) centers, which have distorted‐octahedral coordination geometry, and the molecule crystallizes in the Pbcn space group. The zinc(II) complex displays significant catecholase oxidation activity in methanolic medium through a ligand‐centered radical pathway. This is the first example of catecholase oxidation through a trinuclear zinc(II)–Schiff base complex by means of the formation of a mononuclear intermediate as [ZnL(dtbc)] (dtbc = 3,5‐di‐tert‐butylcatechol). The fluorescence property of 1 indicates that it can serve as a potential photoactive material. It effectively cleaves the double strand of pBR 322 plasmid DNA at a given concentration (25 μM). The complex shows remarkable cytotoxicity against a human hepatocarcinoma cell line (HepG2).
Structural and Electrochemical Studies of Copper(I) Complexes with Diethoxyphosphoryl‐1,10‐phenanthrolines
Authors: Mitrofanov Alexander , Manowong Machima , Rousselin Yoann , Brandès Stéphane , Guilard Roger , Bessmertnykh‐Lemeune Alla , Chen Ping , Kadish Karl M. , Goulioukina Nataliya , Beletskaya Irina
Published: June 2014

Two series of copper(I) complexes with diethoxyphosphoryl‐substituted 1,10‐phenanthroline ligands were synthesized and characterized in the solid state and in solution. The first comprised mixed‐ligand CuI complexes with phenanthroline and triphenylphosphine. The second series includes bis‐chelates with two phenanthroline ligands. According to the X‐ray data for the six complexes, the ditopic phenanthroline ligands exhibit bidentate coordination to the copper(I) atom through two nitrogen atoms in both series. Solution equilibria involving different phenanthroline copper(I) species were studied by 1H and 31P NMR spectroscopy, electrochemistry, and spectroelectrochemistry. The solution speciation of these labile complexes is different for these two series and depends on the nature of solvent and the location of the phosphorus substituent on the phenanthroline backbone. Coordinating solvents can replace a bromide, triphenylphosphine, and even a phenanthroline ligand in the inner coordination sphere of the metal center. Copper(I) complexes with α‐substituted phenanthrolines easily dissociate even in noncoordinating solvents such as CH2Cl2 and CHCl3. Ligand‐exchange reactions leading to less sterically hindered species were observed under the utilized solution conditions. The coordination mode of the phenanthroline chelators does not change under any of the utilized solution conditions, and binding of the phosphoryl group to the metal center was never observed by spectroscopic or spectroelectrochemical methods.
A NiII–Bis(diphosphine)–Hydride Complex Containing Proton Relays – Structural Characterization and Electrocatalytic Studies
Authors: Das Parthapratim , Stolley Ryan M. , van der Eide Edwin F. , Helm Monte L.
Published: June 2014

The synthesis of the 1,5‐diphenyl‐3,7‐diisopropyl‐1,5‐diaza‐3,7‐diphosphacyclooctane ligand, PiPr2NPh2, is reported. Two equivalents of the ligand react with [Ni(CH3CN)6](BF4)2 to form the bis(diphosphine)–NiII complex [Ni(PiPr2NPh2)2](BF4)2, which acts as a proton reduction electrocatalyst. In addition to [Ni(PiPr2NPh2)2]2+, we report the synthesis and structural characterization of the Ni0 complex Ni(PiPr2NPh2)2 and the NiII–hydride complex [HNi(PiPr2NPh2)2]BF4. The [HNi(PiPr2NPh2)2]BF4 complex represents the first NiII–hydride in the [Ni(PR2NR′2)2]2+ family of compounds to be structurally characterized. In addition to the experimental data, the mechanism of electrocatalysis facilitated by [Ni(PiPr2NPh2)2]2+ is analyzed by using linear free energy relationships recently established for the [Ni(PR2NR′2)2]2+ family.
Tuning the Electronic Properties of Piezoresistive Bilayer Films Based on α‐(BEDT‐TTF)2I3
Authors: Lebedev Victor , Laukhina Elena , Laukhin Vladimir , Rovira Concepció , Veciana Jaume
Published: June 2014

We present a study of the influence of the iodine/solvent annealing temperature on the properties of piezoresistive bilayer films with layers of α‐(BEDT‐TTF)2I3 [BEDT‐TTF = bis(ethylenedithio)tetrathiafulvalene]. The formation of the conductive layers was tested by XRD, direct current (dc) conductivity measurements, and SEM, and the electromechanical properties have also been studied. We demonstrate that it is possible to form bilayer (BL) films with an invariant gauge factor of ca. 10 but with the temperature dependence of the resistance variable from metallic to semiconductor‐like by control of the annealing temperature. This control even permits the preparation of a BL film with temperature‐independent resistance.
A Facile Route for Stabilizing Highly Reactive ArTeCl Species Through the Formation of T‐Shaped Tellurenyl Chloride Adducts:quasi‐Planar Zwitterionic [HPy*]TeCl2and [HPm*]TeCl2; Py* = 2‐pyridyl, Pm* = 2‐(4,6‐dimethyl)pyrimidyl
Authors: Khrustalev Victor N. , Matsulevich Zhanna V. , Lukiyanova Julia M. , Aysin Rinat R. , Peregudov Alexander S. , Leites Larissa A. , Borisov Alexander V.
Published: June 2014

Two new stable T‐shaped tellurenyl chloride adducts, viz., [HPy*]TeCl2(1) and [HPm*]TeCl2(2) [Py* = 2‐pyridyl, Pm* = 2‐(4,6‐dimethyl)pyrimidyl], act as close chemical analogs of highly unstable monomeric Py*TeCl and Pm*TeCl. Thequasi‐planar zwitterionic structures of1and2have been studied by experimental (X‐ray diffraction, multinuclear NMR, IR and Raman spectroscopy) and theoretical (DFT and QTAIM) methods. Thus, a novel facile route to stabilize highly reactive Ar*TeCl species (Ar* =N‐functionalized aryl) by the addition of a hydrochloric acid molecule has been demonstrated.
Mechanistic Insights into the Palladium‐Catalyzed Domino Synthesis of 10,11‐Dihydro‐5H‐dibenzo[b,e][1,4]diazepines
Authors: Laha Joydev K. , Satyanarayana Tummalapalli K. S. , Gupta Ankur
Published: June 2014

A palladium‐catalyzed domino approach to the synthesis of 10,11‐dihydro‐5H‐dibenzo[b,e][1,4]diazepines starting from o‐phenylenediamines and 2‐bromobenzyl bromides or tosylates has been developed. Mechanistic studies support the following domino sequence. Intermolecular mono‐N‐benzylation of the o‐phenylenediamine through oxidative palladium insertion, primarily at the benzylic position of the 2‐bromobenzyl bromide, is followed by intramolecular N′‐arylation. The intramolecular N′‐arylation is demonstrated to be facilitated by coordination of a remote auxiliary nitrogen atom to the palladium atom.
Carbene‐Catalyzed Aroylation of a 2‐Chloroquinoxaline N‐Oxide with Aromatic Aldehydes at Room Temperature
Authors: Maichrowski Jan , Bhasin Aman , Sasse Florenz , Kaufmann Dieter E.
Published: June 2014

Starting from easily accessible 2‐chloro‐3‐(cyclopentyloxy)‐7‐fluoroquinoxaline 1‐oxide, 12 new biologically promising aroylquinoxaline N‐oxides were synthesized through carbene‐catalyzed aroylation of the chloro nitrone unit with different aromatic aldehydes in the presence of 1,3‐dimethylimidazolium iodide as the carbene precursor. The optimized reaction conditions tolerated a broad bandwidth of aldehydes and allowed the synthesis of the corresponding ketones in yields up to 87 %. Studies of their biological activities resulted in interesting specific cytotoxic effects against tumor cell lines.
Protecting‐Group‐Free Solid‐Phase Anchoring of Polyphenolic C‐Glucosidic Ellagitannins and Synthesis of 1‐Alkylamino‐Vescalagin Derivatives
Authors: Douat Céline , Berni Emanuela , Jacquet Rémi , Pouységu Laurent , Deffieux Denis , Quideau Stéphane
Published: June 2014

The C‐glucosidic ellagitannins vescalagin and vescalin are among the plant polyphenols that have been shown to interact with protein targets in a specific manner. This work describes a protecting‐group‐free method to immobilize these protein‐binding natural products on a solid support, and a functionalizing cleavage method, which is adaptable to the solution‐phase synthesis of vescal(ag)in derivatives, and which advantageously permitted the preparation of 1‐alkylamino derivatives of vescalagin.
A Unified Strategy for Kainoid Synthesis
Authors: Fujii Masaya , Yokoshima Satoshi , Fukuyama Tohru
Published: June 2014

A unified strategy for kainoid synthesis was developed. The key features of the strategy involve a Claisen–Ireland rearrangement to construct the contiguous stereogenic centers and a palladium‐catalyzed formation of the pyrrolidine ring with complete stereoselectivity. The present protocol has enabled rapid access to a wide range of kainoids with diverse types of substituents (alkenyl, aryl, and alkyl groups) at the 4‐position of the pyrrolidine ring, starting from the common intermediate and appropriate acetic acid derivatives. To test the generality of the strategy, we have accomplished the syntheses of kainic acid, o‐methoxyphenyl derivative (MFPA), and a novel cyclopropyl derivative (CPKA), using 3‐methylbut‐3‐enoic acid, 2‐(2‐methoxyphenyl)acetic acid, and 2‐cyclopropylacetic acid, respectively.
Assignment of the Absolute Configuration and Total Synthesis of (+)‐Caripyrin
Authors: Andernach Lars , Opatz Till
Published: June 2014

The antifungal secondary metabolite (+)‐caripyrin was studied by vibrational circular dichroism spectroscopy. Analysis of the recorded data, with the Boltzmann weighted‐average of the spectra calculated at the B3LYP/6‐311G(d,p) level of theory for all relevant conformers, unequivocally proved the (R,R)‐configuration for the dextrorotatory natural product. Based on this finding, a short enantioselective synthesis of (+)‐caripyrin was developed.
Diazocines on Molecular Platforms
Authors: Tellkamp Tobias , Shen Jun , Okamoto Yoshio , Herges Rainer
Published: June 2014

New diazocines as photochromic switches for the surface functionalization via the “platform approach” were synthesized and characterized. Symmetric diazocines as well as asymmetric molecules based on an indane scaffold were obtained and their photochromic properties were investigated. In a final step, the diazocines were mounted on molecular platforms (triazatriangulenium ions).
Selective Synthesis of Tetrasubstituted 4‐(Tetrazol‐5‐yl)‐1H‐imidazoles from 2‐(Tetrazol‐5‐yl)‐2H‐azirines
Authors: Cardoso Ana Lúcia , Lemos Américo , Pinho e Melo Teresa M. V. D.
Published: June 2014

The reactivity of 2‐(tetrazol‐5‐yl)‐2H‐azirines towards imines in the presence of Lewis acids was explored, which opened a way to new tetrazol‐5‐yl‐1H‐imidazole derivatives. The Zn(OTf)2‐catalyzed reaction allowed the selective synthesis of 4‐(tetrazol‐5‐yl)‐1H‐imidazole derivatives. The presence of phenyl or heteroaromatic substituents in both reactants permitted the synthesis of a wide range of multisubstituted imidazoles, which are molecules with potential relevance in medicinal chemistry.
Vehicle and positive control values from the in vivo rodent comet assay and biomonitoring studies using human lymphocytes: Historical database and influence of technical aspects
Authors: Pant Kamala , Springer S. , Bruce S. , Lawlor T. , Hewitt N. , Aardema M.J.
Published: June 2014

There is increased interest in the in vivo comet assay in rodents as a follow‐up approach for determining the biological relevance of chemicals that are genotoxic in in vitro assays. This is partly because, unlike other assays, DNA damage can be assessed in this assay in virtually any tissue. Since background levels of DNA damage can vary with the species, tissue, and cell processing method, a robust historical control database covering multiple tissues is essential. We describe extensive vehicle and positive control data for multiple tissues from rats and mice. In addition, we report historical data from control and genotoxin‐treated human blood. Technical issues impacting comet results are described, including the method of cell preparation and freezing. Cell preparation by scraping (stomach and other GI tract organs) resulted in higher % tail DNA than mincing (liver, spleen, kidney etc) or direct collection (blood or bone marrow). Treatment with the positive control genotoxicant, ethyl methanesulfonate (EMS) in rats and methyl methanesulfonate in mice, resulted in statistically significant increases in % tail DNA. Background DNA damage was not markedly increased when cell suspensions were stored frozen prior to preparing slides, and the outcome of the assay was unchanged (EMS was always positive). In conclusion, historical data from our laboratory for the in vivo comet assay for multiple tissues from rats and mice, as well as human blood show very good reproducibility. These data and recommendations provided are aimed at contributing to the design and proper interpretation of results from comet assays. Environ. Mol. Mutagen. 55:633–642, 2014. © 2014 Wiley Periodicals, Inc.
A performance‐based framework for adaptive seismic aftershock risk assessment
Authors: Ebrahimian Hossein , Jalayer Fatemeh , Asprone Domenico , Lombardi Anna M. , Marzocchi Warner , Prota Andrea , Manfredi Gaetano
Published: June 2014

Operative seismic aftershock risk forecasting can be particularly useful for rapid decision‐making in the presence of an ongoing sequence. In such a context, limit state first‐excursion probabilities (risk) for the forecasting interval (a day) can represent the potential for progressive state of damage in a structure. This work lays out a performance‐based framework for adaptive aftershock risk assessment in the immediate post‐mainshock environment. A time‐dependent structural performance variable is adopted in order to measure the cumulative damage in a structure. A set of event‐dependent fragility curves as a function of the first‐mode spectral acceleration for a prescribed limit state is calculated by employing back‐to‐back nonlinear dynamic analyses. An epidemic‐type aftershock sequence model is employed for estimating the spatio‐temporal evolution of aftershocks. The event‐dependent fragility curves for a given limit state are then integrated together with the probability distribution of aftershock spectral acceleration based on the epidemic‐type aftershock sequence aftershock hazard. The daily probability of limit state first‐excursion is finally calculated as a weighted combination of the sequence of limit state probabilities conditioned on the number of aftershocks. As a numerical example, daily aftershock risk is calculated for the L'Aquila 2009 aftershock sequence (central Italy). A representative three‐story reinforced concrete frame with infill panels, which has cyclic strength and stiffness degradation, is used in order to evaluate the progressive damage. It is observed that the proposed framework leads to a sound forecasting of limit state first‐excursion in the structure for two limit states of significant damage and near collapse. Copyright © 2014 John Wiley & Sons, Ltd.
A multi‐scale statistical approach to assess the effects of connectivity of road and stream networks on geomorphic channel condition
Authors: Pechenick Alison M. , Rizzo Donna M. , Morrissey Leslie A. , Garvey Kerrie M. , Underwood Kristen L. , Wemple Beverley C.
Published: June 2014

Roads in rural, upland landscapes are important sources of runoff and sediment to waterways. The downstream effects of these sources should be related to the connectivity of roads to receiving waters. Recent studies have explored this idea, but only simple metrics have been used to characterize connectivity and few studies have quantified the downstream effects of road–stream connectivity on sediment or solute budgets and channel morphology. In this study, we evaluated traditional and newly developed connectivity metrics that utilized features of landscape position and delivery pathway to characterize road–stream connectivity in upland settings. Using data on stream geomorphic conditions developed by the Vermont Agency of Natural Resources (Montpelier, VT), we related road connectivity metrics to channel condition on a set of 101 forested, upland streams with minimal development other than predominantly gravel road networks. Logistic regression indicated that measures of road density, proximity and orientation successfully distinguished among categories of stream geomorphic condition at multiple geographic scales. Discriminant function analysis using a set of inherent channel characteristics combined with road connectivity metrics derived at the reach corridor scale successfully distinguished channel condition for over 70% of the channels evaluated. This research contributes to efforts to evaluate the cumulative downstream effects of roads on stream channels and aquatic resources and provides a new means of watershed assessment to derive metrics that can be used to predict channel condition. Copyright © 2014 John Wiley & Sons, Ltd.
Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion
Authors: Kempel Florian , Schartel Bernhard , Marti Julio M. , Butler Kathryn M. , Rossi Riccardo , Idelsohn Sergio R. , Oñate Eugenio , Hofmann Anja
Published: June 2014

An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. Copyright © 2014 John Wiley & Sons, Ltd.
On the composite Riemann problem for multi‐material fluid flows
Authors: Menshov Igor , Zakharov Pavel
Published: June 2014

We develop an Eulerian fixed grid numerical method for calculating multi‐material fluid flows. This approach relates to the class of interface capturing methods. The fluid is treated as a heterogeneous mixture of constituent materials, and the material interface is implicitly captured by a region of mixed cells that have arisen owing to numerical diffusion. To suppress this numerical diffusion, we propose a composite Riemann problem (CRP), which describes the decay of an initial discontinuity in the presence of a contact point between two different fluids, which is located off the initial discontinuity point. The solution to the CRP serves to calculate multi‐material no mixed numerical flux without introducing any material diffusion. We discuss the CRP solution and its implementation in the multi‐material fluid Godunov method. Numerical results show that a simple framework of the CRP greatly improves capturing material interfaces in the Godunov method and reproduces many of the advantages of more complicated interface tracking multi‐material treatments. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis and Characterization of Diphosphenes Bearing Fused‐Ring Bulky Rind Groups
Authors: Li Baolin , Tsujimoto Shota , Li Yongming , Tsuji Hayato , Tamao Kohei , Hashizume Daisuke , Matsuo Tsukasa
Published: June 2014

Diphosphenes stabilized by the fused‐ring bulky 1,1,3,3,5,5,7,7‐octa‐R‐substituted s‐hydrindacen‐4‐yl (Rind) groups have been obtained as orange crystals by the reduction of the corresponding dichlorophosphines, (Rind)PCl2, with lithium naphthalenide (LiNaph). The molecular structures of (Eind)PCl2 and the diphosphenes, (Eind)PP(Eind) and (EMind)PP(EMind), having the bulky Eind and the less bulky EMind groups, have been confirmed by X‐ray crystallography. The formation of the PP bond has been fully characterized by spectroscopic methods.