bluuebunny/crossref_metadata_2025 huggingface dataset:
Demographic drivers of a refugee species: large‐scale experiments guide strategies for reintroductions of hirola
Authors: Ali Abdullahi H. , Kauffman Matthew J. , Amin Rajan , Kibara Amos , King Juliet , Mallon David , Musyoki Charles , Goheen Jacob R.
Published: December 2017

Effective reintroduction strategies require accurate estimates of vital rates and the factors that influence them. The hirola (Beatragus hunteri) is the rarest antelope on Earth, with a global population size of <500 individuals restricted to the Kenya–Somali border. We estimated vital rates of hirola populations exposed to varying levels of predation and rangeland quality from 2012 to 2015, and then built population matrices to estimate the finite rate of population change (λ) and demographic sensitivities. Mean survival for all age classes and population growth was highest in the low‐predation–high‐rangeland‐quality setting (λ = 1.08 ± 0.03 [mean ± SE]), and lowest in the high‐predation–low‐rangeland‐quality setting (λ = 0.70 ± 0.22). Retrospective demographic analyses revealed that increased fecundity (the number of female calves born to adult females annually) and female calf survival were responsible for higher population growth where large carnivores were absent. In contrast, variation in adult female survival was the primary contributor to differences in population growth attributable to rangeland quality. Our analyses suggest that hirola demography is driven by a combination of top‐down (predation) and bottom‐up (rangeland quality) forces, with populations in the contemporary geographic range impacted both by declining rangeland quality and predation. To enhance the chances of successful reintroductions, conservationists can consider rangeland restoration to boost both the survival and fecundity of adult females within the hirola's historical range.
Incomplete tidal restoration may lead to persistent high CH4 emission
Authors: Emery Hollie E. , Fulweiler Robinson W.
Published: December 2017

Salt marshes provide a range of critical ecosystem services including high rates of carbon sequestration. Recent recognition of the importance of these ecosystems has led to an interest in restoring marshes that have been degraded by human activities. Tidal restriction from coastal development can alter salt marsh plant and animal communities as well as marsh biogeochemistry. However, much less is known about how tidal restriction, and subsequent tidal restoration, may alter greenhouse gas emissions. Since salt marshes typically have lower emissions of methane than freshwater wetlands, tidal restoration that increases the salinity in a restricted marsh could theoretically improve the net global warming potential of a marsh by lowering methane emissions. In this study, we examined the emissions of carbon dioxide, methane, and nitrous oxide at four temperate salt marshes, three of which had been restricted and subsequently restored. Greenhouse gas fluxes were poorly correlated with environmental parameters (biomass, temperature, moisture, sediment organic content, porewater salinity and pH, etc.) normally considered to be primary drivers of salt marsh biogeochemical processes. Carbon dioxide and nitrous oxide emissions and uptake were not influenced by the restriction and restoration history of the marshes. Despite comparable salinity, methane emissions in one partially restored marsh were 25 times higher than those in unimpacted reference sites 13+ years after restoration. However, methane emissions from the other restored sites were equal to or significantly lower than those from unimpacted reference sites. This study highlights that we cannot assume recovering ecosystems will function like unimpacted ones, especially if restoration is incomplete.
Rodent herbivory and fire differentially affect plant species recruitment based on variability in life history traits
Authors: Sharp Bowman Tiffanny R. , McMillan Brock R. , St. Clair Samuel B.
Published: December 2017

Rodent consumers can have strong top‐down effects on plant community development via seed predation, but their influence on seedling recruitment and how it varies depending on disturbance history and plant traits are largely unknown. Over a two‐year period, we experimentally tested the influence of rodents and fire on seedling survival of 14 plant species with contrasting growth forms and life history traits in the Great Basin Desert. Seedling survival was dramatically increased by rodent exclusion and fire and was greater in 2013 than 2012. Rodent abundance was an order of magnitude lower in 2013 than 2012 and across both years showed a negative linear relationship with mean seedling survival of all 14 plant species (R2 = −0.62). There was strong variability in plant species sensitivity to rodent herbivory with a more than 10‐fold difference in mortality risk between the most sensitive species and the most resistant species and a high degree of variability in survival among all species. Mortality risk of forb species was double that of grass species and there was a trend toward higher mortality of native species compared to introduced species. The results suggest that rodent herbivory may be an important determinant of plant community assembly in desert ecosystems with plant life history strategies and growth form traits serving as important survival filters. Post‐fire environments and low rodent years likely provide windows of opportunity for greater seedling recruitment due to a release from rodent herbivory pressure.
Ligand Influence on the Photophysical Properties and Electronic Structures of Tungsten Iodide Clusters
Authors: Seyboldt Alexander , Enseling David , Jüstel Thomas , Ivanović Milutin , Peisert Heiko , Chassé Thomas , Meyer H.‐Jürgen
Published: December 2017

Compounds containing the [Mo6I8L6]2– ion in which L is an inorganic or organic ligand show remarkable photophysical properties. Similar properties were observed for the corresponding compounds based on octahedral tungsten clusters. The properties of these photosensitizers are significantly impacted by the six outer iodide ligands of [W6I8I6]2–. To analyze the role of the outer ligands, we prepared and structurally characterized octahedral tungsten cluster compounds with [W6I8I6]2– and [M6I8L6]2– ions (M = W, Mo; L = para‐toluenesulfonate). The distinct photophysical properties of the clusters were analyzed with respect to their photoluminescence (i.e., phosphorescence) and luminescence quenching in the presence of molecular oxygen. The electronic structures were analyzed through photoelectron spectroscopy to expose differences in the electronic situations of the compounds.
A Simple Approach to Generate Hollow Carbon Nanospheres Loaded with Uniformly Dispersed Metal Nanoparticles
Authors: Li Yunqi , Tan Haibo , Takei Toshiaki , Hossain Md. Shahriar A. , Islam Md. Tofazzal , Alshehri Saad M. , Ahamad Tansir , Salunkhe Rahul R. , Pradhan Subrata , Henzie Joel , Yamauchi Yusuke , Ariga Katsuhiko
Published: December 2017

We describe a simple and versatile method to synthesize hollow carbon nanospheres (HCNs) loaded with well‐distributed metal nanoparticles (i.e., Ir‐HCNs, MoO2‐HCNs, and WO2/WO3‐HCNs). This procedure uses the electrostatic interaction between negatively charged metal precursors and positively charged micelle templates made of poly(styrene‐b‐2‐vinyl pyridine‐b‐ethylene oxide). The ion pairs are neutralized inside the micelles and then coated with a layer of phenolic resol. Pyrolysis transforms the nanoparticles into HCNs decorated with metal/metal oxide nanoparticles. HCNs are an excellent substrate for the in situ growth of metal nanoparticles, and this procedure can even provide reasonable control over the average size of the metal nanoparticles.
Synthesis of A‐Ring Precursors of 1α,25‐Dihydroxyvitamin D3 Analogues Functionalized at C‐2
Authors: Sigüeiro Rita
Published: December 2017

A flexible approach to an A‐ring building block for new 1α,25‐dihydroxyvitamin D analogues functionalized at C‐2 as potential clinical candidates is described. The synthesis of alcohol 5 starts from (R)‐carvone, and uses a Criegee rearrangement to selectively degrade the isopropenyl side‐chain as one of the key steps.
SIENA‐XL for improving the assessment of gray and white matter volume changes on brain MRI
Authors: Battaglini Marco , Jenkinson Mark , De Stefano Nicola ,   for the Alzheimer's Disease Neuroimaging Initiative
Published: December 2017

In this article, SIENA‐XL, a new segmentation‐based longitudinal pipeline is introduced, for: (i) increasing the precision of longitudinal volume change estimation for white (WM) and gray (GM) matter separately, compared with cross‐sectional segmentation methods such as SIENAX; and (ii) avoiding potential biases in registration‐based methods when Jacobians are used, with a smoothing extent larger than spatial scale between tissue‐interfaces, which is where atrophy usually occurs. SIENA‐XL implements a new brain extraction procedure and a multi‐time‐point intensity equalization step before performing the final segmentation that also includes separate segmentation of deep GM structures by using FMRIB's Integrated Registration and Segmentation Tool. The detection of GM and WM volume changes with SIENA‐XL was evaluated using different healthy control (HC) and multiple sclerosis (MS) MRI datasets and compared with the traditional SIENAX and two Jacobian‐based approaches, SPM12 and SIENAX‐JI (a version of SIENAX including Jacobian integration ‐ JI). In scan‐rescan data from HCs, SIENA‐XL showed: (i) a significant decrease in error, of 50–70% when compared with SIENAX; (ii) no significant differences in error when compared with SIENAX‐JI and SPM12 in a scan‐rescan HC dataset that included repositioning. When tested in a HC dataset with scan‐rescan both at baseline and after 1 year of follow‐up, SIENA‐XL showed: (i) significantly higher precision (P < 0.01) than SIENAX; (ii) no significant differences to SIENAX‐JI and SPM12. Finally, in a dataset of 79 MS patients with a 2 years follow‐up, SIENA‐XL showed a substantial reduction of sample size, by comparison with SIENAX, SIENAX‐JI, and SPM12, for detecting treatment effects of 25, 30, and 50%. Hum Brain Mapp 39:1063–1077, 2018. © 2017 Wiley Periodicals, Inc.
Significance and mechanism of androgen receptor overexpression and androgen receptor/mechanistic target of rapamycin cross‐talk in hepatocellular carcinoma
Authors: Zhang Hong , Li Xiao‐Xing , Yang Yang , Zhang Yanjie , Wang Hui‐Yun , Zheng X.F. Steven
Published: December 2017

Hepatocellular carcinoma (HCC) is a male‐dominant cancer, and androgen receptor (AR) has been linked to the pathogenesis of HCC. However, AR expression and its precise role in HCC remain controversial. Moreover, previous antiandrogen and anti‐AR clinical trials in HCC failed to demonstrate clinical benefits. In this study, we found that AR is overexpressed in the nucleus of approximately 37% of HCC tumors, which is significantly associated with advanced disease stage and poor survival. AR overexpression in HCC cells markedly alters AR‐dependent transcriptome, stimulates oncogenic growth, and determines therapeutic response to enzalutamide, a second generation of AR antagonist. However, AR inhibition evokes feedback activation of AKT‐mTOR (mechanistic target of rapamycin) signaling, a central regulator for cell growth and survival. On the other hand, mTOR promotes nuclear AR protein expression by restraining ubiquitin‐dependent AR degradation and enhancing AR nuclear localization, providing a mechanistic explanation for nuclear AR overexpression in HCC. Finally, cotargeting AR and mTOR shows significant synergistic anti‐HCC activity and decreases tumor burden by inducing apoptosis in vivo. Conclusion: Nuclear AR overexpression is associated with the progression and prognosis of HCC. However, enzalutamide alone has limited therapeutic utility attributed to feedback activation of the AKT‐mTOR pathway. Moreover, mTOR drives nuclear AR overexpression. Cotargeting AR and mTOR is a promising therapeutic strategy for HCC. (Hepatology 2018;67:2271‐2286).
Fibrolamellar carcinoma in the Carney complex: PRKAR1A loss instead of the classic DNAJB1‐PRKACA fusion
Authors: Graham Rondell P. , Lackner Carolin , Terracciano Luigi , González‐Cantú Yessica , Maleszewski Joseph J. , Greipp Patricia T. , Simon Sanford M. , Torbenson Michael S.
Published: December 2017

Fibrolamellar carcinomas are characterized by activation of protein kinase A, a kinase composed of catalytic and regulatory subunits. PRKACA encodes a catalytic subunit of protein kinase A, and almost all fibrolamellar carcinomas have a heterozygous 400‐kb deletion that leads to the fusion of DNAJB1 and PRKACA. The resulting DNAJB1‐PRKACA fusion transcript is believed to activate protein kinase A by dysregulation of the catalytic portion of the protein. In contrast, PRKAR1A encodes one of the regulatory subunits of protein kinase A. We hypothesized that loss of function of this regulatory unit could also lead to protein kinase A activation and thus to fibrolamellar carcinoma. Because PRKAR1A mutations underlie the Carney complex, we searched for liver tumors in individuals with the Carney complex. We identified 3 individuals with fibrolamellar carcinomas and a personal history of the Carney complex. All three tumors displayed the typical morphology of fibrolamellar carcinoma and were positive for arginase, cytokeratin 7, and cluster of differentiation 68. Fluorescence in situ hybridization was negative for PRKACA rearrangements. However, PRKAR1A sequencing identified pathogenic mutations in two of two cases with successful sequencing. In addition, all three cases were negative for PRKAR1A protein expression, consistent with inactivation of this key regulatory unit of protein kinase A. We also identified one additional fibrolamellar carcinoma in an individual without a documented history of the Carney complex who was negative for PRKACA rearrangements but had loss of PRKAR1A protein expression as well as PRKAR1A mutations. Conclusion: Fibrolamellar carcinoma can be part of the Carney complex; in this setting, fibrolamellar carcinomas have inactivating PRKAR1A mutations instead of the DNAJB1‐PRKACA fusion gene found in sporadic fibrolamellar carcinomas, providing an alternate means for activation of protein kinase A. (Hepatology 2017).
Role of angiogenic factors in the pathogenesis and management of pre‐eclampsia
Authors: Ngene Nnabuike C. , Moodley Jagidesa
Published: December 2017

The cause of pre‐eclampsia is unknown. Different postulates have been developed to explain its pathogenesis. The two‐stage theory and angiogenic imbalance are two notable postulates of the disease. Together, they propose that there is a lack of cytotrophoblastic invasion of the uterine spiral arteries in pre‐eclampsia. The lumen of these arteries remains narrow instead of converting to the wide channels seen in normal pregnancy, and result in poor placental perfusion. Coupled with maternal susceptibility, this process leads to the release of mediators, including an excess of anti‐angiogenic factors that result in the clinical manifestations of the disease. Circulating levels of anti‐angiogenic factors such as soluble fms‐like tyrosine kinase‐1 increase, whereas pro‐angiogenic factors such as placental growth factor decrease. Assessment of the circulating concentrations of these angiogenic factors, such as the soluble fms‐like tyrosine kinase‐1/placental growth factor ratio, has diverse clinical relevance in pre‐eclampsia. The present review describes the role of angiogenic factors in the pathogenesis and management of pre‐eclampsia.
Ni/γ‐Al2O3 catalyzed hydrogenation sequence of conjugated double bonds in 2‐ethyl‐2‐hexenal and reaction kinetics
Authors: Zhao Lili , Wang Yi , An Hualiang , Zhao Xinqiang , Wang Yanji
Published: December 2017

BACKGROUND

2‐ethylhexanol (2EHO) is an important organic chemical, which is mainly used in the manufacture of plasticizers. At present, the industrial manufacture of 2EHO is generally carried out by gas‐phase hydrogenation of 2‐ethyl‐2‐hexenal, which has high energy consumption. So it is of significance to study liquid‐phase hydrogenation of 2‐ethyl‐2‐hexenal.

RESULTS

Several byproducts were found such as 3‐methylheptane, 2‐ethylhexyl butyrate, 2,4‐diethyloctanol, 2,4‐diethyloctanal, 5,7‐diethylundecane and 2‐ethylhexyl‐2‐ethylhexanoate in the reaction system of 2‐ethyl‐2‐hexenal liquid‐phase hydrogenation catalyzed by Ni/γ‐Al2O3 and a reaction network was proposed. The CC bond of 2‐ethyl‐2‐hexenal molecule was hydrogenated prior to the CO bond hydrogenation and furthermore the CO bond was hardly hydrogenated until the CC bond hydrogenation finished. The kinetics of liquid‐phase hydrogenation of 2‐ethyl‐2‐hexenal catalyzed by Ni/γ‐Al2O3 was studied and the result demonstrated that both 2‐ethyl‐2‐hexenal hydrogenation to 2‐ethylhexanal (CC bond hydrogenation) and 2‐ethylhexanal hydrogenation to 2‐ethylhexanol (CO bond hydrogenation) were first‐order irreversible reactions.

CONCLUSIONS

It is made clear by means of online infrared analysis that the hydrogenation of CO bond is difficult to achieve before completion of the hydrogenation of CC bond. The 2‐ethylhexanal hydrogenation reaction, whose activation energy is higher, is the rate‐determining step in the entire hydrogenation process. © 2017 Society of Chemical Industry
Long‐term viral suppression and immune recovery during first‐line antiretroviral therapy: a study of an HIV‐infected adult cohort in Hanoi, Vietnam
Authors: Tanuma Junko , Matsumoto Shoko , Haneuse Sebastien , Cuong Do Duy , Vu Tuong Van , Thuy Pham Thi Thanh , Dung Nguyen Thi , Dung Nguyen Thi Hoai , Trung Nguyen Vu , Kinh Nguyen Van , Oka Shinichi
Published: December 2017

Introduction

Achieving viral suppression is key in the global strategy to end the HIV epidemic. However, the levels of viral suppression have yet to be described in many resource‐limited settings.

Methods

We investigated the time to virologic failure (VF; defined as a viral load of ≥1000 copies/ml) and changes in CD4 counts since starting antiretroviral therapy (ART) in a cohort of HIV‐infected adults in Hanoi, Vietnam. Factors related to the time to VF and impaired early immune recovery (defined as not attaining an increase in 100 cells/mm3 in CD4 counts at 24 months) were further analysed.

Results

From 1806 participants, 225 were identified as having VF at a median of 50 months of first‐line ART. The viral suppression rate at 12 months was 95.5% and survival without VF was maintained above 90% until 42 months. An increase in CD4 counts from the baseline was greater in groups with lower baseline CD4 counts. A younger age (multivariate hazard ratio (HR) 0.75, vs. <30), hepatitis C (HCV)‐antibody positivity (HR 1.43), and stavudine (d4T)‐containing regimens (HR 1.4, vs. zidovudine (AZT)) were associated with earlier VF. Factors associated with impaired early immune recovery included the male sex (odds ratio (OR) 1.78), HCV‐antibody positivity (OR 1.72), d4T‐based regimens (OR 0.51, vs. AZT), and nevirapine‐based regimens (OR 0.53, vs. efavirenz) after controlling for baseline CD4 counts.

Conclusion

Durable high‐rate viral suppression was observed in the cohort of patients on first‐line ART in Vietnam. Our results highlight the need to increase adherence support among injection drug users and HCV co‐infected patients.
How effective are common household preparations on removing pesticide residues from fruit and vegetables? A review
Authors: Chung Stephen WC
Published: December 2017

Nowadays, the use of pesticides is inevitable for pest control in crops, especially for fruit and vegetables. After the harvest from raw agricultural commodities, the amount of pesticide residues in food is mainly influenced by the storage, handling and processing that follow. If good agricultural and good manufacturing practices are enforced effectively, the amount of pesticide residues would be brought below the corresponding maximum residue level. Thus, the consumption of raw and/or prepared fruit and vegetables would be safe. Nonetheless, reports regarding pesticide residues in fruit or vegetables on mass media have been worrying consumers, who are concerned about the adverse effects of pesticide residues. As a result, consumers perform household processing before consumption to reduce any related risks. However, can these preparations effectively remove pesticide residues? Reviewing the extensive literature, it showed that, in most cases, washing and soaking can only lead to a certain degree of reduction in residue level, while other processing such as peeling, soaking in chemical baths and blanching can reduce pesticide residues more effectively. In general, the behaviour of residues during processing can be rationalised in terms of the physico‐chemical properties of the pesticide and the nature of the process. In contrast, the reported studies are diversified and some areas still lack sufficient studies to draw any remarks. Recommendations are provided with respect to the available information that aims to formulate an environmental friendly, cost‐effective and efficient household processing of fruit and vegetables to reduce pesticide residues. © 2017 Society of Chemical Industry
A review of structural brain abnormalities in Pallister‐Killian syndrome
Authors: Poulton Cathryn , Baynam Gareth , Yates Clarissa , Alinejad‐Rokny Hamid , Williams Simon , Wright Helen , Woodward Karen J. , Sivamoorthy Soruba , Peverall Joanne , Shipman Peter , Ravine David , Beilby John , Heng Julian Ik‐Tsen
Published: December 2017

Background

Pallister‐Killian syndrome (PKS) is a rare multisystem developmental syndrome usually caused by mosaic tetrasomy of chromosome 12p that is known to be associated with neurological defects.

Methods

We describe two patients with PKS, one of whom has bilateral perisylvian polymicrogyria (PMG), the other with macrocephaly, enlarged lateral ventricles and hypogenesis of the corpus callosum. We have also summarized the current literature describing brain abnormalities in PKS.

Results

We reviewed available cases with intracranial scans (n = 93) and found a strong association between PKS and structural brain abnormalities (77.41%; 72/93). Notably, ventricular abnormalities (45.83%; 33/72), abnormalities of the corpus callosum (25.00%; 18/72) and cerebral atrophy (29.17%; 21/72) were the most frequently reported, while macrocephaly (12.5%; 9/72) and PMG (4.17%; 3/72) were less frequent. To further understand how 12p genes might be relevant to brain development, we identified 63 genes which are enriched in the nervous system. These genes display distinct temporal as well as region‐specific expression in the brain, suggesting specific roles in neurodevelopment and disease. Finally, we utilized these data to define minimal critical regions on 12p and their constituent genes associated with atrophy, abnormalities of the corpus callosum, and macrocephaly in PKS.

Conclusion

Our study reinforces the association between brain abnormalities and PKS, and documents a diverse neurogenetic basis for structural brain abnormalities and impaired function in children diagnosed with this rare disorder.
Tolerance design of patient‐specific range QA using the DMAIC framework in proton therapy
Authors: Rah Jeong‐Eun , Shin Dongho , Manger Ryan P. , Kim Tae Hyun , Oh Do Hoon , Kim Dae Yong , Kim Gwe‐Ya
Published: December 2017

Purpose

To implement the DMAIC (Define‐Measure‐Analyze‐Improve‐Control) can be used for customizing the patient‐specific QA by designing site‐specific range tolerances.

Methods

The DMAIC framework (process flow diagram, cause and effect, Pareto chart, control chart, and capability analysis) were utilized to determine the steps that need focus for improving the patient‐specific QA. The patient‐specific range QA plans were selected according to seven treatment site groups, a total of 1437 cases. The process capability index, Cpm was used to guide the tolerance design of patient site‐specific range.

Results

For prostate field, our results suggested that the patient range measurements were capable at the current tolerance level of ±1 mm in clinical proton plans. For other site‐specific ranges, we analyzed that the tolerance tends to be overdesigned to insufficient process capability calculated by the patient‐specific QA data. The customized tolerances were calculated for treatment sites. Control charts were constructed to simulate the patient QA time before and after the new tolerances were implemented. It is found that the total simulation QA time was decreased on average of approximately 20% after establishing new site‐specific range tolerances. We simulated the financial impact of this project. The QA failure for whole process in proton therapy would lead up to approximately 30% increase in total cost.

Conclusion

DMAIC framework can be used to provide an effective QA by setting customized tolerances. When tolerance design is customized, the quality is reasonably balanced with time and cost demands.
Development of depth encoding small animal PET detectors using dual‐ended readout of pixelated scintillator arrays with SiPMs
Authors: Kuang Zhonghua , Sang Ziru , Wang Xiaohui , Fu Xin , Ren Ning , Zhang Xianming , Zheng Yunfei , Yang Qian , Hu Zhanli , Du Junwei , Liang Dong , Liu Xin , Zheng Hairong , Yang Yongfeng
Published: December 2017

Purpose

The performance of current small animal PET scanners is mainly limited by the detector performance and depth encoding detectors are required to develop PET scanner to simultaneously achieve high spatial resolution and high sensitivity. Among all depth encoding PET detector approaches, dual‐ended readout detector has the advantage to achieve the highest depth of interaction (DOI) resolution and spatial resolution. Silicon photomultiplier (SiPM) is believed to be the photodetector of the future for PET detector due to its excellent properties as compared to the traditional photodetectors such as photomultiplier tube (PMT) and avalanche photodiode (APD). The purpose of this work is to develop high resolution depth encoding small animal PET detector using dual‐ended readout of finely pixelated scintillator arrays with SiPMs.

Methods

Four lutetium‐yttrium oxyorthosilicate (LYSO) arrays with 11 × 11 crystals and 11.6 × 11.6 × 20 mm3 outside dimension were made using ESR, Toray and BaSO4 reflectors. The LYSO arrays were read out with Hamamatsu 4 × 4 SiPM arrays from both ends. The SiPM array has a pixel size of 3 × 3 mm2, 0.2 mm gap in between the pixels and a total active area of 12.6 × 12.6 mm2. The flood histograms, DOI resolution, energy resolution and timing resolution of the four detector modules were measured and compared.

Results

All crystals can be clearly resolved from the measured flood histograms of all four arrays. The BaSO4 arrays provide the best and the ESR array provides the worst flood histograms. The DOI resolution obtained from the DOI profiles of the individual crystals of the four array is from 2.1 to 2.35 mm for events with E > 350 keV. The DOI ratio variation among crystals is bigger for the BaSO4 arrays as compared to both the ESR and Toray arrays. The BaSO4 arrays provide worse detector based DOI resolution. The photopeak amplitude of the Toray array had the maximum change with depth, it provides the worst energy resolution of 21.3%. The photopeak amplitude of the BaSO4 array with 80 μm reflector almost doesn't change with depth, it provides the best energy resolution of 12.9%. A maximum timing shift of 1.37 ns to 1.61 ns among the corner and the center crystals in the four arrays was obtained due to the use of resistor network readout. A crystal based timing resolution of 0.68 ns to 0.83 ns and a detector based timing resolution of 1.26 ns to 1.45 ns were obtained for the four detector modules.

Conclusions

Four high resolution depth encoding small animal PET detectors were developed using dual‐ended readout of pixelated scintillator arrays with SiPMs. The performance results show that those detectors can be used to build a small animal PET scanner to simultaneously achieve uniform high spatial resolution and high sensitivity.
Multiplicity‐edited 1H‐1H TOCSY experiment
Authors: Nolis Pau , Parella Teodor
Published: December 2017

A 1H‐1H total correlation spectroscopy (TOCSY) experiment incorporating 13C multiplicity information is proposed. In addition, broadband 1H homodecoupling in the indirect dimension can be implemented using a perfect BIRD module that affords exclusive 1H chemical shift evolution with full decoupling of all heteronuclear and homonuclear (including 2JHH) coupling constants. As a complement to the normal TOCSY and the recent PSYCHE‐TOCSY experiments, this novel multiplicity‐edited TOCSY experiment distinguishes between CH/CH3 (phased up) and CH2 (phased down) cross‐peaks, which facilitates resonance analysis and assignment.
Distortion of KB estimates of endothelin‐1 ETA and ETB receptor antagonists in pulmonary arteries: Possible role of an endothelin‐1 clearance mechanism
Authors: Angus James A. , Hughes Richard J. A. , Wright Christine E.
Published: December 2017

Dual endothelin ETA and ETB receptor antagonists are approved therapy for pulmonary artery hypertension (PAH). We hypothesized that ETB receptor‐mediated clearance of endothelin‐1 at specific vascular sites may compromise this targeted therapy. Concentration‐response curves (CRC) to endothelin‐1 or the ETB agonist sarafotoxin S6c were constructed, with endothelin receptor antagonists, in various rat and mouse isolated arteries using wire myography or in rat isolated trachea. In rat small mesenteric arteries, bosentan displaced endothelin‐1 CRC competitively indicative of ETA receptor antagonism. In rat small pulmonary arteries, bosentan 10 μmol L−1 left‐shifted the endothelin‐1 CRC, demonstrating potentiation consistent with antagonism of an ETB receptor‐mediated endothelin‐1 clearance mechanism. Removal of endothelium or L‐NAME did not alter the EC50 or Emax of endothelin‐1 nor increase the antagonism by BQ788. In the presence of BQ788 and L‐NAME, bosentan displayed ETA receptor antagonism. In rat trachea (ETB), bosentan was a competitive ETB antagonist against endothelin‐1 or sarafotoxin S6c. Modeling showed the importance of dual receptor antagonism where the potency ratio of ETA to ETB antagonism is close to unity. In conclusion, the rat pulmonary artery is an example of a special vascular bed where the resistance to antagonism of endothelin‐1 constriction by ET dual antagonists, such as bosentan or the ETB antagonist BQ788, is possibly due to the competition of potentiation of endothelin‐1 by blockade of ETB‐mediated endothelin‐1 clearance located on smooth muscle and antagonism of ETA‐ and ETB‐mediated contraction. This conclusion may have direct application for the efficacy of endothelin‐1 antagonists for treating PAH.
Application of ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites
Authors: Xu Xiafen , Li Xinhui , Liang Xianrui
Published: December 2017

Rationale

Metabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption.

Methods

Three isoflavone glycosides and their metabolites were identified using ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry (UPLC/QTOF‐MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work.

Results

Two metabolites from ononin, three metabolites from irilone‐4′‐O‐β‐D‐glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H]+ ion were observed for all the three isoflavone glycosides. The characteristic retro‐Diels‐Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites.

Conclusions

A selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF‐MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone.
An Efficient Ecofriendly Enantioselective Organocatalytic Ring‐Closing Reaction of 2‐Hydroxychalcone via Intramolecular Oxa‐Michael Reaction
Authors: Singh Ashawani Kumar , Mangawa Shrawan Kumar , Kumar Arvind , Dixit A. K. , Awasthi Satish Kumar
Published: December 2017

An organocatalyzed highly asymmetric cascade oxa‐Michael addition reaction for the synthesis of flavanone from 2‐hydroxychalcone has been developed. This method works well with low catalyst loading and has broad range substrate scope, furnishing the desired product in excellent yield and displays an intrinsic enantioselectivity of upto 99.9 % ee. This method provides a straightforward entry into highly functionalized chiral flavanone derivatives.
Syntheses, Crystal Structures and Spectroscopic Studies of Bis[1‐methyl‐3‐(methoxycarbonylmethyl)‐benzimidazolium]2+ [CuBr4]2− and [ZnBr4]2− Compounds
Authors: Czekański Łukasz , Hoffmann Stanisław K. , Barczyński Piotr , Gąsowska A. , Zalewska Alina , Goslar Janina , Ratajczak‐Sitarz Małgorzata , Katrusiak Andrzej
Published: December 2017

X‐ray diffraction structure of two new bis [1‐methyl‐3‐(methoxycarbonylmethyl) benzimidazolium]2+ [CuBr4]2− and [ZnBr4]2− compounds has been determined. Zn‐crystal is monoclinic with perfect Td symmetry of the ZnBr4 tetrahedron, whereas the Cu‐compound is orthorhombic with D2d symmetry of CuBr4 tetrahedron. The difference in these structures is described as due to the static Jahn‐Teller effect. Vibrational spectroscopy (1800–3200 cm−1) identified hydrogen bond network. NIR‐UV‐Vis spectra (5000–50000 cm−1) are dominated by ligand‐to‐metal bands with d‐d transition contribution. EPR results (Q‐band) analyzed in terms of the MO‐theory showed a very strong delocalization of unpaired electron density on ligands accompanied by the Cu(II) 4pz orbital contribution. This effect is partially compensated by charge transfer transitions to the EPR g‐factor.
Hydrogen Generation via Activation of X‐H Bonds in Ammonia and Water by an MoI Complex
Authors: Bandeira Nuno A. G. , Veiros Luís F. , Bo Carles
Published: December 2017

The mechanism of H2 production from a Mo(I) complex with terpyridine and phosphine ancillary ligands, [Mo(NH3)(Phtbpy)(PPh2Me)2]+ was computationally investigated by DFT calculations. Several tentative pathways were tested and the most favourable one corresponds to a bimolecular mechanism that starts with the oxidative addition of the N−H bond in NH3, yielding a 7‐coordinate Mo(III) species with a hydride and an amido ligand. In a second step two such intermediates join to form H2 and the Mo(II) co‐product, [Mo(NH2)(Phtbpy)(PPh2Me)2]+. The first step has the highest barrier and its value (26.5 kcal/mol) is in agreement with mild reaction conditions, as experimentally observed (6 hours at 60 °C). The entire process occurs with spin change from S=
in the initial complex to S=0 in the products. The same mechanism is also operative using water and methanol as ligands, the corresponding free energy barrier being ca. 7 kcal/mol lower than the one calculated for NH3.
Deeply Repairing Surface States with Wet Chemistry Methods: Enhanced Performance in TiO2 Nanowire Arrays‐Based Optoelectronic Device
Authors: Zha Chenyang , Zhang Jun‐Jie , Shen Liming , Dong Shuai , Gupta Arunava , Bao Ningzhong
Published: December 2017

One‐dimensional (1D) single‐crystalline rutile TiO2 nanowire arrays (TiO2 NWAs) have generally been considered superior over TiO2 nanoparticle films for the optoelectronic applications. We discovered that the conventional oxygen annealing method cannot efficiently repair the surface trap states of the TiO2 NWAs that significantly influence the charge diffusion. In this work, we demonstrate a highly effective wet chemistry method to repair the surface states by the successive ionic layer adsorption and reaction (SILAR). The density functional calculations (DFT)‐based simulation has been used to explain the physical mechanism of reparation of the surface oxygen vacancies of by CdS or PbS quantum dots (QDs). The analysis results of photoluminescence spectroscopy (PL) and electrochemical analysis conformed the enhanced optoelectronic conversion efficiency. A 20–30% improvement in solar cell performance has been obtained over the PbS or CdS QDs coated dye‐sensitized solar cells. The SILAR method for deeply repairing the surface trap states can be extended to the systhesis of other semiconducting nanocrystals and its solar energy conversion applications.
The Ritter Reaction of 2‐Oxoaldehydes at Room Temperature: Divergent Behaviour towards Acid Strength.
Authors: Khan Shahnawaz , Kumar Atul , Gupta Raman , Ahmed Qazi N.
Published: December 2017

An efficient, novel, atom economical and selective amidation method for the generation of mono and di‐Ritter products using 2‐oxoaldehydes under acidic environment at room temperature was successfully developed. The di‐Ritter products obtained are accessed in good yields when stirred in the presence of 20 mol % H2SO4, and the mono products were selectively obtained in moderate yields with CuOTf as catalyst. However, the yields of the latter were optimized by the addition of SeO2.
Ln8 (Ln= Gd, Ho, Er, Yb) Butterfly Core‐Exhibiting Magnetocaloric Effect and Field‐Induced SMM Behavior for Er Analouge
Authors: Bala Sukhen , Adhikary Amit , Bhattacharya Sudeshna , Bishwas Mousumi Sen , Poddar Pankaj , Mondal Raju
Published: December 2017

In this article, we report four pyridyl‐pyrazolyl based polynuclear cluster complexes with Ln8 {Ln=[GdIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)2(MeOH)(1), [HoIII8(μ3‐OH)4(L1)4(DEA)4Cl4](2), [ErIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)(MeOH)(H2O)(3), [YbIII8(μ3‐OH)4(L1)4(DEA)4Cl4](DMF)(MeOH)(4) [DEA = Diethanolamine] cores. The impetus for this study was to explore the magnetic behaviour of lanthanide ions which are often ignored or overlooked. X‐ray crystal analysis show that these complexes are isostructural and exhibit an interesting butterfly like topology. The semi‐rigidity and asymmetric nature of the ligand led to different coordination environment around the metal centres. The lanthanide ions adopt two types of geometry, a bicapped trigonal prism and a distorted square antiprismatic geometry around the metal center. Such dissimilar coordination environments around the lanthanide centre can have profound effects on their magnetic behaviour. Indeed, the magnetic measurements revealed significant magnetocaloric effect for octanuclear gadolinium complex 1 with magnetic entropy change (−ΔSm ) of 31.4 J kg−1 K−1 for ΔH = 9 T at T = 3 K whereas Er analogue complex 3 displayed SMM behavior.
A Categorical Naked‐Eye Detection of Cu2+ and Zn2+ through a Donor‐Acceptor‐Donor (D‐A‐D)‐Type Salicylaldimine: An Experimental and Theoretical Approach
Authors: Kumar Virendra , Diwan Uzra , Sanskriti Isha , Mishra Rakesh K. , Upadhyay K. K.
Published: December 2017

A Schiff base viz., 2,3‐bis‐(3, 5‐di‐tert‐butyl‐2‐hydroxybenzylidene) amino maleonitrile (TBCN), having donor–acceptor–donor (D–A–D) type constitution exhibited Cu2+ and Zn2+ guided specific modulations in its ICT (intramolecular charge transfer) characteristics. The corresponding naked eye changes for Cu2+ and Zn2+ involved the shifting of characteristic ICT band of TBCN at ∼472 nm (yellow) to ∼ 566 nm (pink) and ∼590 nm (indigo blue) respectively in a semi‐aqueous medium (EtOH:H2O in a ratio of 8:2 v/v). The TBCN as well as its ensembles with Cu2+ and Zn2+ were fully characterized through their single crystal XRD studies along with spectroscopic and mass spectral studies. The DFT and the time‐dependent DFT calculations provided a genuine rationale for separate naked eye colorimetric changes of TBCN for Cu2+ and Zn2+.
Strategies to Produce Chlorinated Indole‐3‐Acetic Acid and Indole‐3‐Acetic Acid Intermediates
Authors: Patallo Eugenio P. , Walter Antje , Milbredt Daniela , Thomas Marion , Neumann Madeleine , Caputi Lorenzo , O'Connor Sarah , Ludwig‐Müller Jutta , van Pée Karl‐Heinz
Published: December 2017

Tryptophan and indole derivatives are common precursors in many natural biosynthetic pathways. In recent years it has been shown that the substrate specificity of tryptophan halogenases is much more relaxed than previously thought. Using the tryptophan 7‐halogenase PrnA, the tryptophan 6‐halogenase ThdH, and the tryptophan 5‐halogenase PyrH we achieved the regioselective mono‐halogenation of indole‐3‐acetic acid (IAA), which has not been reported as a substrate of tryptophan halogenases to date. The tryptophan 5‐halogenase gene was introduced into Arabidopsis thaliana leading to the formation of 5‐chlorotryptophan, 5‐chloroindole‐3‐acetonitrile and 5‐chloro‐3‐indole acetic acid by A. thaliana. PyrH activity could also be demonstrated for the plant‐produced halogenase in vitro. These results show the potential of flavin‐dependent halogenases to generate novel halogenated auxins or other secondary metabolites in vitro and in vivo by plants.
Syntheses, Crystal Structures and Photophysical Aspects of Discrete and Polymeric Azido‐Bridged Zinc(II) and Cadmium(II) Complexes: Sensing Properties and Structural Resemblance
Authors: Roy Shuvayan , Bhattacharya Sagarika , Mohanta Sasankasekhar
Published: December 2017

The work in this report presents syntheses, characterization, crystal structures and steady state and time resolved photophysical properties of four compounds of composition [ZnII3L12(N3)4] (1), [CdII3L22(N3)4]n (2), [ZnII2L2(N3)3]n (3) and [CdII2L1(N3)3]n (4), where HL1 and HL2 are the Schiff base ligands, obtained on 1:1 condensation of 3‐ethoxysalicylaldehyde (for HL1)/3‐methoxysalicylaldehyde (for HL2) and N,N,2,2‐tetramethyl‐1,3‐propanediamine. Compound 1 is a discrete trizinc(II) system, while the other three compounds are one‐dimensional coordination polymers, where the building units are, respectively, tricadmium(II), dizinc(II) and dicadmium(II) moieties. The nuclearities of the cores in the ZnII–azido compound from HL1 and the CdII–azido compound from HL2 are similar (1 and 2 are trinuclear) and, similarly, the ZnII–azido compound from HL2 and the CdII–azido compound from HL1 are similar (3 and 4 are dinuclear), revealing an unusual structural resemblance of two metal ions of two different rows in the periodic table as the function of slight change in the ligand periphery (OEt in HL1, OMe in HL2). The steady state/time‐resolved photophysical properties reveal that cadmium(II) enhances slightly but zinc(II) enhances appreciably the fluorescence of the Schiff base ligands HL1 and HL2. It has been found that both HL1 and HL2 are fluorogenic sensors of zinc(II).
Graphitic Carbon Nitride (g‐C3N4)‐derived Fe‐N‐C Catalysts for Selective Hydrodeoxygenation of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran
Authors: Li Jiang , Zhang Jun‐jie , Liu He‐yang , Liu Jun‐ling , Xu Guang‐yue , Liu Jia‐xing , Sun Hui , Fu Yao
Published: December 2017

As Fe is more abundant and economic than Cu and Ni, it is probably a more attractive non‐noble alternative to precious metals in biomass conversions, for which usually require promising catalysts for large‐scale production. In this work, economic and environmental benign heterogeneous iron catalysts prepared by simultaneous pyrolysis of graphitic carbon nitride and iron precursors on activated carbon, were demonstrated to be active for the hydrodeoxygenation of biomass‐derived 5‐hydroxymethylfurfural to 2,5‐dimethylfuran. The effect of pyrolysis temperature, support, iron content, the type of g‐C3N4 and iron precursor, and N/Fe ratio were explored thoroughly, and reaction parameters such reaction temperature and H2 pressure were also investigated. The highest DMF yield of 85.7 % was obtained at 240 °C for 3 h, which is comparable to that obtained over iron catalysts prepared from precious iron complexes. The investigation of reaction pathway showed that 5‐methylfurfural was the possible intermediate. The stability of as‐prepared Fe‐N‐C catalyst could be improved after treatment with aqueous HCl solution.
Novel Benzimidazole‐Containing Heterocyclic Compounds: Synthesis, Physical Properties and OLED Application
Authors: Shen Yuqiang , Li Junbo , Chen Shao , Wan Jiaqi , Zhao Yongbiao , Lu Zheng‐Hong , Li Miao , Yang Li , Yu Xianglin , Chen Dugang , Pan Zhiquan
Published: December 2017

Three novel heterocyclic compounds containing one (M1) or two (isomers M2 and M3) benzimidazole units have been synthesized and fully characterized. The isomers M2 and M3 could be easily separated by column chromatography. Studies showed that the decrease of intermolecular π‐π stackings could enhance the fluorescence intensity of target compounds obviously. The single‐site compound M1 shows the lowest fluorescent quantum yield (ΦM1=0.013) in CH2Cl2 than that of the double‐site isomers M2 (anti‐type, ΦM2=0.148) and M3 (syn‐type, ΦM3=0.053). Electroluminescent performances of M2 and M3 in organic light‐emitting diodes were studied. As expected, M2 exhibits more than 2 times higher current efficiency than M3 with M2 showing a maximum current efficiency of 7.8 cd/A as compare to 3.6 cd/A for M3.
Fluorine‐Substituted Ligands Induce Structural Diversity of Coordination Compounds
Authors: Khavasi Hamid Reza , Rahimi Narjes
Published: December 2017

Seven inorganic coordination compounds based on HgBr2 and Ln−F ligands, in which Ln−F are N‐(fluorinated phenyl)‐2‐pyrazinecarboxamide, bearing fluorine substituent in different position on phenyl ring have been synthesized. These complexes, [HgBr2(L2−F)2]n, 1, [HgBr2L3−F]n, 2, [HgBr2L4−F]n, 3, [HgBr2L2,5−F]n, 4, [HgBr2(L2,6−F)2], 5, [HgBr2L2,3,4−F], 6, and [HgBr2L2,3,4,5−F]n, 7, are characterized in order to get precise insight into the fluorine substituent effect on the coordination structures. The crystal structure data resulting from X‐ray diffraction reveal that, in spite of the same metal, counter ion and reaction conditions, overall structural diversity is evident in all cases. Accordingly, fluorinated ligand exercise influence on not only first coordination sphere but also supramolecular architecture and overall construction. As a matter of fact, small changes in the position and number of fluorine existed on the phenyl ring direct both first and second coordination sphere around metal ion.
Nitrogen‐Functionalized Active Carbon‐Supported Non‐Noble Nickel Nanoparticles with High Dispersity and Enhanced Catalytic Performance in Nitro Naphthalene Hydrogenation
Authors: Xiong Wei , Wang Liping , Cai Guoxiao , Yang Yongzhe , Hao Fang , Liu Pingle , Luo Hean
Published: December 2017

Nitrogen‐functionalized active carbons were prepared by post‐treatment method and used as supports for loading nickel to prepare liquid‐phase hydrogenation catalysts. The post‐treatment conditions were investigated, and these nitrogen‐functionalized active carbons supported nickel catalysts were characterized and used in the nitro naphthalene compounds hydrogenation. The characterization results show that the nitrogen‐functionalized active carbon prepared at 800 oC (N‐AC‐800) shows higher nitrogen content and pyridinic nitrogen species. And its supported nickel catalyst (Ni/N‐AC‐800) shows the most finely and extremely dispersion of nickel nanoparticles, the highest content of Ni0, and the largest metallic surface areas and the best H2 uptake quantity. Moreover, Ni/N‐AC‐800 also shows the best catalytic performance in nitro compounds hydrogenation reaction. The yield of 1,5‐diaminonaphthalene reaches to 94.75%, and the catalyst could be recycled for four times and maintained stable catalytic performance. Ni/N‐AC‐800 also shows good catalytic performance in 1‐nitronaphthalene and 1,8‐dinitronaphthalene hydrogenation.