bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Catalytic Enantioselective Hydroxyamination of α‐Aryl‐α‐Cyanoacetates with 2‐Nitrosopyridines
Authors: Zhang Jingchuan , Fu Kai , Lin Lili , Lu Yan , Liu Xiaohua , Feng Xiaoming
Published: February 2018

The highly enantioselective totally N‐selective hydroxyamination reaction of α‐aryl‐α‐cyanoacetates with 2‐nitrosopyridines was realized by using a chiral N,N′‐dioxide/Mg(OTf)2 complex as catalyst, which enriches the nitroso chemistry. A variety of 2‐cyano‐2‐[hydroxyl(pyrydin‐2‐yl)amino]acetates with quaternary stereocenters and potential antibacterial activities were obtained in excellent yields with good to excellent ee values under as low as 0.05 mol % catalyst loading. The products could be easily transformed to useful α‐amino amides and 1,2‐diamines. Besides, a possible transition state model was proposed to elucidate the origin of the chirality induction.
Tandem Functionalization in a Highly Branched Polymer with Layered Structure
Authors: Cao Xiaosong , Shi Yi , Gan Weiping , Gao Haifeng
Published: February 2018

A hyperbranched polymer with multilayer structure was developed to demonstrate the possibility of highly efficient tandem functionalization reactions at different domains within one nanostructured platform. The polymer scaffold was constructed by chain‐growth copper‐catalyzed azide–alkyne cycloaddition polymerization of three functional monomers with sequential monomer addition in one pot. Subsequent reactions with different monomer units resulted in efficient functionalization of each segment with construction of a highly sophisticated polymer structure by a robust procedure. As a proof of concept, the ability of this polymer structure to quantitatively load six species of guest molecules through three different types of conjugation reactions was demonstrated.
A sensitivity analysis for tissue development by varying model parameters and input variables
Authors: Paim Ágata , Tessaro Isabel C. , Pranke Patricia , Cardozo Nilo S. M.
Published: February 2018

Phenomenological models can help in the study of the relation between mass transport and cell growth in three‐dimensional porous scaffolds, which is one of the main challenges of tissue engineering. Thus, using a model for cell proliferation and glucose diffusion and consumption, the dimensionless parameters and input variables were varied to determinate those which affect the model output the most. The simulations were performed with the software OpenFOAM, and the results were compared through a sensitivity analysis for the parameters. It was observed that the model is more sensitive to the dimensionless parameters related to cell proliferation, death, and nutrient uptake, and that dimensionless initial glucose concentration and scaffold porosity had a higher impact on cell volume fraction and on dimensionless glucose concentration. When compared to data from experimental studies, the computational results showed that the studied model is capable of representing the phenomena involved in tissue development in vitro.
Effect of type D personality on smoking status and their combined impact on outcome after acute myocardial infarction
Authors: Imbalzano Egidio , Vatrano Marco , Quartuccio Sebastiano , Ceravolo Roberto , Ciconte Vincenzo Antonio , Rotella Paola , Pardeo Renato , Trapani Giovanni , De Fazio Pasquale , Segura‐Garcia Cristina , Costantino Rossella , Saitta Antonino , Mandraffino Giuseppe
Published: February 2018

Background

Smoking cessation is correlated with several psychological, social, biological, and pharmacological aspects. The combined tendency to experience negative emotions and to inhibit the expression of these emotions is indicated as “type D personality,” an independent risk marker for clinical outcome in cardiac disease. Despite this effect of type D personality on cardiovascular disease, it is still unclear whether this personality trait may influence smoking cessation after a myocardial infarction.

Hypothesis

we hypothesized that there is a relationship between type D personality and smoking persistence in acute coronary syndrome patients, and this association may predict a worse long‐term prognosis.

Methods

The study enrolled 231 patients with ST‐segment elevation myocardial infarction, treated with primary percutaneous coronary intervention. Type D scale 14 (ds 14) was administered upon admission to the hospital.

Results

After controlling for demographic and clinical confounders, non–type D patients reported statistically significant higher frequencies of smoking cessation when compared with the type D group. In addition, the presence of this psychological factor anticipates significantly the onset of smoking during adolescence. Furthermore, current type D smokers had a higher incidence of cardiovascular events during long‐term follow‐up.

Conclusions

Type D personality and smoking status increase the risk of cardiac events. An emotionally stressed personality and persistence of smoking after the first cardiac event, and mostly their mutual influence, indicate a population at high cardiovascular risk.
Synthesis and Characterization of the R27S Genetic Variant of Insulin‐like Peptide 5
Authors: Zaykov Alexander N. , Gelfanov Vasily M. , Liu Fa , DiMarchi Richard D.
Published: February 2018

We report the synthesis and in vitro bioactivity assessment for an insulin‐like peptide 5 (INSL5) analogue that was recently discovered as a genetic mutation in an Amish population. The mutation was associated with improved metabolic status, and receptor‐based antagonism was proposed as a potential mechanism for the altered phenotype. We determined the specific peptide analogue to be fully potent and of maximal efficacy at the human relaxin family peptide receptor 4 (RXFP4), suggesting an alternative basis for the observed effect. In preparation of this synthetically challenging hormone, we have introduced several improvements such as implementation of isoacyl chemistry for high‐efficiency preparation of INSL5 B‐chain and selective intramolecular A6‐11 disulfide formation as a first step in sequential disulfide assembly.
Simulation, design, and test of an elliptical surface coil for magnetic resonance imaging and spectroscopy
Authors: Giovannetti Giulio , Flori Alessandra , De Marchi Daniele , Matarazzo Giuseppe , Frijia Francesca , Burchielli Silvia , Montanaro Domenico , Aquaro Giovanni Donato , Menichetti Luca
Published: February 2018

The simplest design of surface coils for magnetic resonance imaging (MRI) applications is circular and square loops, both producing a magnetic field perpendicular to the coil plane in the central region‐of‐interest (ROI), with an amplitude that decreases along the coil axis. However, a surface coil constituted by a loop with different geometry could be necessary when particular field‐of‐views (FOVs) are desired, especially for performing imaging in an elongated region. This can be achieved by using an elliptical loop, which can guarantee a wide longitudinal FOV and a good penetration in deep sample regions. This work proposes the application of a method for elliptical coil Signal‐to‐Noise Ratio (SNR) estimation previously developed for circular and square loop design, in which coil inductance and resistance are analytically calculated and the magnetic field pattern is estimated using the magnetostatic approach, while the sample‐induced resistance is calculated with the vector potential calculation method. In the second part of the paper, we propose the simulation and the design of a transmit/receive elliptical coil for MRI in mice with a 3T clinical scanner. We also evaluated the coil performance in a preliminary magnetic resonance spectroscopy (MRS) study in phantom.
Misconceptions and Realities of the Prescription Opioid Epidemic
Authors: Schnoll Sidney H.
Published: February 2018

The abuse of opioids in the US is not a new problem. In 1973 David Musto published his book, The American Disease: Origins of Narcotic Control, which described the problem as dating back to the time of the Civil War. Continued attempts to address it through legislation, law enforcement, prevention, treatment, and the development of less abuseable pain relievers have shown limited success.
Visible Light‐Driven Water Oxidation on an In Situ N2‐Intercalated WO3 Nanorod Photoanode Synthesized by a Dual‐Functional Structure‐Directing Agent
Authors: Li Dong , Takeuchi Ryouchi , Chandra Debraj , Saito Kenji , Yui Tatsuto , Yagi Masayuki
Published: February 2018

With a view to developing a photoanode for visible light‐driven water oxidation in solar water splitting cells, pure‐monoclinic WO3 nanorod crystals with N2 intercalated into the lattice were synthesized by using hydrazine with a dual functional role—as an N atom source for the in situ N2 intercalation and as a structure‐directing agent for the nanorod architecture—to gain higher incident photon‐to‐current conversion efficiency at 420 nm than with most previously reported WO3 electrodes.
Sufficient Utilization of Zirconium Ions to Improve the Structure and Surface properties of Nickel‐Rich Cathode Materials for Lithium‐Ion Batteries
Authors: He Tao , Lu Yun , Su Yuefeng , Bao Liying , Tan Jing , Chen Lai , Zhang Qiyu , Li Weikang , Chen Shi , Wu Feng
Published: February 2018

We doped Zr4+ ions in the outer layer of Ni0.8Co0.1Mn0.1(OH)2 by coprecipitation. The distribution of Zr4+ in the final cathode materials showed a gradient distribution because of ion migration during the thermal treatment. The doped layer was confirmed by using various analysis methods (energy‐dispersive X‐ray spectroscopy, XRD, X‐ray photoelectron spectroscopy, and TEM), which implies that Zr4+ can not only occupy both the transition metal slabs and Li slabs but also form a Li2ZrO3 layer on the surface as a highly ion‐conductive layer. The doped Zr4+ in the transition metal slabs can stabilize the crystal structure because of the strong Zr−O bond energy, and the doped Zr4+ in the Li slabs can act as pillar ions to improve the structural stability and reduce cation mixing. The gradient doping can take advantage of the “pillar effect” and restrain the “blocking effect” of the pillar ions, which reduces irreversible capacity loss and improves the cycling and rate performance of the Ni‐rich cathode materials. The capacity retention of the modified sample reached 83.2 % after 200 cycles at 1C (200 mA g−1) at 2.8–4.5 V, and the discharge capacity was up to 164.7 mAh g−1 at 10C. This effective strategy can improve the structure stability of the cathode material while reducing the amount of non‐electrochemical active dopant because of the gradient distribution of the dopant. In addition, the highly ion‐conductive layer of Li2ZrO3 on the surface can improve the rate performance of the cathode.
Aqueous Hydrogenation of Levulinic Acid to 1,4‐Pentanediol over Mo‐Modified Ru/Activated Carbon Catalyst
Authors: Cui Jinglei , Tan Jingjing , Zhu Yulei , Cheng Fangqin
Published: February 2018

A highly efficient and green process was developed for direct conversion of levulinic acid into 1,4‐pentanediol over Mo‐modified Ru/activated carbon (AC) catalyst in a continuous fixed‐bed reactor. The Ru–MoOx/AC catalyst was found to be efficient for the aqueous‐phase hydrogenation of levulinic acid to 1,4‐pentanediol, whereby a high yield (96.7 mol %) of 1,4‐pentanediol was obtained under mild reaction conditions (70 °C, 4 MPa H2).
FPGA‐based implementation for improved control scheme of grid‐connected PV system with 3‐phase 3‐level NPC‐VSI
Authors: Jena Satabdy , Panda Gayadhar , Peesapati Rangababu
Published: February 2018

The large scale penetration of renewable energy resources has boosted the need of using improved control technique and modular power electronic converter structures for efficient and reliable operation of grid‐connected systems. This study investigates the performance of a grid‐connected 3‐phase 3‐level neutral‐point clamped voltage source inverter for renewable energy integration by using improved current control technique. For medium or high‐voltage grid interfacing, the multilevel inverter structure is generally used to reduce the voltage stress across the switching device as well as the harmonic distortion. The neutral‐point clamped voltage source inverter is controlled by using decoupling technique along with the proper grid synchronization via moving average filter–based phase‐locked loop. The moving average filter–based phase‐locked loop is used to reduce the delay in grid angle estimation under balanced as well as distorted grid conditions. A Lyapunov‐based approach for analysing the stability of the system has also been discussed. In this study, the hardware‐in‐loop (HIL) simulation of the control algorithm and the grid synchronization technique is realized using Virtex‐6 FPGA ML605 evaluation kit. The performance of the system is analyzed by conducting a time‐domain simulation in the Matlab/Simulink platform and its performance is examined in the HIL environment. The simulation and the hardware cosimulation results are presented to validate the effectiveness of the proposed control scheme.
An efficient in‐network caching decision algorithm for Internet of things
Authors: Doan Van Dong , Ai Qingsong
Published: February 2018

Recently, content‐centric networking (CCN) has become one of the important technologies for enabling the future networks. Along with its recognized potentialities as a content retrieval and dissemination solution, CCN has been also recently considered as a promising architecture for the Internet of things (IoT), because of 2 main features such as named‐based routing and in‐network caching. However, IoT is characterized by challenging features: small storage capacity of resource‐constrained devices due to cost and limitation of energy and especially transient data that impose stringent requirements on the information freshness. As a consequence, the intrinsic caching mechanisms existing in CCN approach do not well suit IoT domains; hence, providing a specific caching policy at intermediate nodes is a very challenging task. This paper proposes an effective multiattribute in‐network caching decision algorithm that performs a caching strategy in CCN‐IoT network by considering a set of crucial attributes including the content store size, hop count, particularly key temporal properties like data freshness, and the node energy level. Simulation results proved that our proposed approach outperforms 2 cache management schemes (probabilistic least recently used and AlwaysCache–first in first out in terms of improving total hit rate, reducing data retrieval delay, and enhancing content reusability in IoT environment).
Cytologic features of needle aspiration of ovarian sex cord tumor with annular tubules: Report of two cases and literature review
Authors: Chen Xiaowei , Crapanzano John P. , Gonzalez Abel A. , Hamele‐Bena Diane
Published: February 2018

Sex cord tumor with annular tubules (SCTAT) is a rare ovarian tumor with characteristic microscopic morphologic features. Diagnosis most often is based on examination of tissue specimens. Cytologic features of this tumor rarely have been described in the English literature. Herein, we report cytologic findings of cyst aspiration fluid in two cases of SCTAT, with cyto‐histologic correlation.
Forest structure provides the income for reproductive success in a southern population of Canada lynx
Authors: Kosterman Megan K. , Squires John R. , Holbrook Joseph D. , Pletscher Daniel H. , Hebblewhite Mark
Published: February 2018

Understanding intrinsic and extrinsic drivers of reproductive success is central to advancing animal ecology and characterizing critical habitat. Unfortunately, much of the work examining drivers of reproductive success is biased toward particular groups of organisms (e.g., colonial birds, large herbivores, capital breeders). Long‐lived mammalian carnivores that are of conservation concern, solitary, and territorial present an excellent situation to examine intrinsic and extrinsic drivers of reproductive success, yet they have received little attention. Here, we used a Canada lynx (Lynx canadensis) data set, from the southern periphery of their range, to determine if reproductive success in a solitary carnivore was consistent with capital or income breeding. We radio‐marked and monitored 36 female Canada lynx for 98 lynx years. We evaluated how maternal characteristics and indices of food supply (via forest structure) in core areas influenced variation in body condition and reproductive success. We characterized body condition as mass/length and reproductive success as whether a female produced a litter of kittens for a given breeding season. Consistent with life‐history theory, we documented a positive effect of maternal age on body condition and reproductive success. In contrast to predictions of capital breeding, we observed no effect of pre‐pregnancy body condition on reproductive success in Canada lynx. However, we demonstrated statistical effects of forest structure on reproductive success in Canada lynx, consistent with predictions of income breeding. The forest characteristics that defined high success included (1) abundant and connected mature forest and (2) intermediate amounts of small‐diameter regenerating forest. These attributes are consistent with providing abundant, temporally stable, and accessible prey resources (i.e., snowshoe hares; Lepus americanus) for lynx and reinforce the bottom‐up mechanisms influencing Canada lynx populations. Collectively, our results suggest that lynx on the southern range periphery exhibit an income breeding strategy and that forest structure supplies the income important for successful reproduction. More broadly, our insights advance the understanding of carnivore ecology and serve as an important example on integrating long‐term field studies with ecological theory to improve landscape management.
Dual‐guild herbivory disrupts predator‐prey interactions in the field
Authors: Blubaugh Carmen K. , Asplund Jacob S. , Eigenbrode Sanford D. , Morra Matthew J. , Philips Christopher R. , Popova Inna E. , Reganold John P. , Snyder William E.
Published: February 2018

Plant defenses often mediate whether competing chewing and sucking herbivores indirectly benefit or harm one another. Dual‐guild herbivory also can muddle plant signals used by specialist natural enemies to locate prey, further complicating the net impact of herbivore–herbivore interactions in naturally diverse settings. While dual‐guild herbivore communities are common in nature, consequences for top‐down processes are unclear, as chemically mediated tri‐trophic interactions are rarely evaluated in field environments. Combining observational and experimental approaches in the open field, we test a prediction that chewing herbivores interfere with top‐down suppression of phloem feeders on Brassica oleracea across broad landscapes. In a two‐year survey of 52 working farm sites, we found that parasitoid and aphid densities on broccoli plants positively correlated at farms where aphids and caterpillars rarely co‐occurred, but this relationship disappeared at farms where caterpillars commonly co‐occurred. In a follow‐up experiment, we compared single and dual‐guild herbivore communities at four local farm sites and found that caterpillars (P. rapae) caused a 30% reduction in aphid parasitism (primarily by Diaeretiella rapae), and increased aphid colony (Brevicoryne brassicae) growth at some sites. Notably, in the absence of predators, caterpillars indirectly suppressed, rather than enhanced, aphid growth. Amid considerable ecological noise, our study reveals a pattern of apparent commensalism: herbivore–herbivore facilitation via relaxed top‐down suppression. This work suggests that enemy‐mediated apparent commensalism may override constraints to growth induced by competing herbivores in field environments, and emphasizes the value of placing chemically mediated interactions within their broader environmental and community contexts.
The role of angiotensin receptor–neprilysin inhibitors in cardiovascular disease—existing evidence, knowledge gaps, and future directions
Authors: Ambrosy Andrew P. , Mentz Robert J. , Fiuzat Mona , Cleland John G.F. , Greene Stephen J. , O'Connor Christopher M. , Teerlink John R. , Zannad Faiez , Solomon Scott D.
Published: February 2018

Although traditional renin–angiotensin system antagonists including angiotensin‐converting enzyme inhibitors and angiotensin receptor blockers have revolutionized the treatment of cardiovascular disease (CVD), the pivotal PARADIGM‐HF trial demonstrated that sacubitril/valsartan, an angiotensin receptor–neprilysin inhibitor (ARNI), was superior to an angiotensin‐converting enzyme inhibitor in reducing cardiovascular morbidity and mortality in patients with heart failure and reduced ejection fraction. However, despite international regulatory approval and strong recommendations in the guidelines, uptake of sacubitril/valsartan has been disappointing. Sacubitril/valsartan is now the focus of a large programme of clinical trials testing the hypothesis that ARNIs may supplant conventional renin–angiotensin system inhibitors across the spectrum of CVD, including hypertension, secondary prevention after myocardial infarction, and heart failure with preserved ejection fraction. This review summarizes the existing evidence, knowledge gaps, and future directions of ARNIs in CVD based on discussions between clinical trialists, industry representatives, and regulatory authorities at the 2016 Global CardioVascular Clinical Trialists Forum in Washington, D.C.
MDSCs drive the process of endometriosis by enhancing angiogenesis and are a new potential therapeutic target
Authors: Zhang Tao , Zhou Juhua , Man Gene Chi Wai , Leung Kam Tong , Liang Bo , Xiao Bo , Ma Xinting , Huang Shaoyan , Huang Huaxiang , Hegde Venkatesh L. , Zhong Yin , Li Yanmin , Kong Grace Wing Shan , Yiu Alice Ka Wah , Kwong Joseph , Ng Pak Cheung , Lessey Bruce A. , Nagarkatti Prakash S. , Nagarkatti Mitzi , Wang Chi Chiu
Published: February 2018

Endometriosis affects women of reproductive age via unclear immunological mechanism(s). Myeloid‐derived suppressor cells (MDSCs) are a heterogeneous group of myeloid cells with potent immunosuppressive and angiogenic properties. Here, we found MDSCs significantly increased in the peripheral blood of patients with endometriosis and in the peritoneal cavity of a mouse model of surgically induced endometriosis. Majority of MDSCs were granulocytic, produced ROS, and arginase, and suppressed T‐cell proliferation. Depletion of MDSCs by antiGr‐1 antibody dramatically suppressed development of endometrial lesions in mice. The chemokines CXCL1, 2, and 5 were expressed at sites of lesion while MDSCs expressed CXCR‐2. These CXC‐chemokines promoted MDSC migration toward endometriotic implants both in vitro and in vivo. Also, CXCR2‐deficient mice show significantly decreased MDSC induction, endometrial lesions, and angiogenesis. Importantly, adoptive transfer of MDSCs into CXCR2‐KO mice restored endometriotic growth and angiogenesis. Together, this study demonstrates that MDSCs play a role in the pathogenesis of endometriosis and identifies a novel CXC‐chemokine and receptor for the recruitment of MDSCs, thereby providing a potential target for endometriosis treatment.
The Supramolecular and Coordination Chemistry of Cobalt(II) Extraction by Phosphinic Acids
Authors: Carson Innis , Tasker Peter A. , Love Jason B. , Moser Michael , Fischmann Adam J. , Jakovljevic Boban , Soderstrom Matthew D. , Morrison Carole A.
Published: February 2018

A combination of mass spectrometry, DFT calculations and31P{1H} NMR spectroscopy has been used to define the mode of action of the commercial cobalt extractant, bis(2,4,4‐trimethylpentyl)phosphinic acid (CYANEX®272,L1H) in Co recovery. The nature of the CoIIcomplexes formed in the water‐immiscible phase is determined largely by the propensity of phosphinates to form strong interligand H‐bonds in the outer coordination sphere and also to form stable µ2‐Co–O–P–O–Co bridges. At low Co loading levels, the predominant species is the 4:1 complex, [Co(L1·L1H)2], in which coordinated neutral phosphinic acid ligands form strong H‐bonds to adjacent anionic phosphinates. At higher Co loading, oligomers such as [(L1·L1H)Co(L12Co)n(L1·L1H)] are formed with µ2‐phosphinate bridging, resulting in a substantial increase in the viscosity of the water‐immiscible phase. The presence of tris(2,4,4‐trimethylpentyl)phosphine oxide (L2) in the commercial formulation reduces the viscosity because its incorporation into oligomeric complexes such as [(L2)Co{L13CoL1CoL13Co}mL1] can terminate chains, resulting in a lower average molecular weight. The uptake of Zn byL1H shows a very similar dependence of viscosity on loading, and DOSY spectra and mass spectrometry demonstrate that higher molecular weight species are present at high Zn loading.
An Inverse Opal Structured Halide Perovskite Photocatalyst
Authors: Schünemann Stefan , Tüysüz Harun
Published: February 2018

We employ a colloidal crystal templating approach to fabricate ordered macro‐mesoporous CsPbBr3 and demonstrate its superior photocatalytic activity compared to its non‐templated counterpart in the degradation of an organic pollutant. The presented templating approach reduces charge carrier diffusion pathways and increases the surface area of the halide perovskite. Furthermore, the crystal structure, and the morphology of the templated halide perovskite are stable under photocatalytic conditions, which results in a constant photocatalytic performance in recycling experiments. The presented concept is applicable for other photocatalytic reactions and can thus advance the novel field of halide perovskites in photocatalysis.
Synthesis, Structures, and Catalytic Properties of Dinuclear Iridium(I) Complexes with a Hexadentate Macrocyclic Diamine‐Tetracarbene Ligand
Authors: Fei Fan , Lu Taotao , Yang Chu‐Fan , Chen Xue‐Tai , Xue Zi‐Ling
Published: February 2018

Two dinuclear macrocyclic IrI NHC complexes, [Ir2(L1)(COD)2](PF6)2 (1, COD = 1,5‐cyclooctadiene) and [Ir2Cl(L1)(COD)]Cl (2), were prepared by the reaction between [{IrCl(COD)}2] and macrocyclic N‐heterocyclic carbene (NHC) ligand precursor (H4L1)(PF6)4 containing four benzimidazolium and two secondary amino groups. Furthermore, 1 and 2 were carbonylated to give [Ir2(L1)(CO)4](PF6)2 (3) and [Ir2Cl(L1)(CO)2]Cl (4), respectively. Notably, 1 can capture the chloride ion to turn itself into 2 with accompanying transformation from cis to trans configuration. Complexes 2 and 4 have unusual five‐coordinate IrI centers, which are rarely reported for IrI NHC complexes. The catalytic properties of 1, 2, and related mononuclear IrI complex [Ir(L2)(COD)](PF6) (5, L2 = bis‐NHC ligand) were evaluated in 1,4 conjugate addition reactions of arylboronic acids to cyclohex‐1‐en‐2‐one. These three complexes are the first examples of IrI NHC species showing such catalytic properties in 1,4‐addition reactions, and have higher catalytic activities than the reported IrI complex [Ir(hydroquinone)(COD)]BF4.
[Co(MeTAA)] Metalloradical Catalytic Route to Ketenes via Carbonylation of Carbene Radicals
Authors: Chirila Andrei , van Vliet Kaj M. , Paul Nanda D. , de Bruin Bas
Published: February 2018

An efficient synthetic strategy towards beta‐lactams, amides, and esters involving “in situ” generation of ketenes and subsequent trapping with nucleophiles is presented. Carbonylation of carbene radical intermediates using the cheap and highly active cobalt(II) tetramethyltetraaza[14]annulene catalyst [Co(MeTAA)] provides a convenient one‐pot synthetic protocol towards substituted ketenes. N‐tosylhydrazones are used as carbene precursors, thereby bridging the gap between aldehydes and ketenes. Activation of these carbene precursors by the metalloradical cobalt(II) catalyst affords CoIII‐carbene radicals, which subsequently react with carbon monoxide to form ketenes. In the presence of a nucleophile (imine, alcohol, or amine) in the reaction medium the ketene is immediately trapped, resulting in the desired products in a one‐pot synthetic protocol. The β‐lactams formed upon reaction with imines are produced in a highly trans‐selective manner.
A Bird's Eye View of Atropisomers Featuring a Five‐Membered Ring
Authors: Bonne Damien , Rodriguez Jean
Published: February 2018

An atropisomer is a member of a subclass of restricted rotational conformers – this restricted rotation giving rise to stereogenic sigma bonds – that can be isolated as separate chemical species. Most atropisomer are six‐membered‐ring biaryl or heterobiaryl derivatives. The aim of this microreview is to shed light on a less common class of atropisomers, those containing at least one five‐membered hetero‐ or carbocycle and displaying variously a stereogenic C–N, C–C, or even N–N chemical bond. After a short introduction, the occurrence of atropisomers in nature is presented, as well as the synthetic efforts – encompassing non‐stereoselective and diastereoselective strategies, together with an update on very recent enantioselective approaches – devoted to such axially chiral compounds. Finally, a special focus is placed on their important utilization as original and efficient ligands for metal complexes.
A New Facet of Azatriene Reactivity: A Short Cut to 5‐Amino‐3‐methyl‐4‐(1H‐pyrrol‐1‐yl)thiophene‐2‐carboxylates and 5‐Amino‐3‐methyl‐4‐(1H‐pyrrol‐1‐yl)thiophene‐2‐carbonitriles
Authors: Nedolya Nina A. , Tarasova Olga A. , Albanov Alexander I. , Trofimov Boris A.
Published: February 2018

An simple and expedient approach to highly functionalized tetrasubstituted thiophenes from readily accessible starting materials [(1H‐pyrrol‐1‐yl)allene, isothiocyanates, and alkyl 2‐bromoacetates or 2‐bromoacetonitrile] has been developed. The method is based on the one‐pot synthesis and fast in‐situ cyclization of alkyl 2‐{[2‐(1H‐pyrrol‐1‐yl)buta‐2,3‐dienimidoyl]sulfanyl}acetates or cyanomethyl 2‐(1H‐pyrrol‐1‐yl)buta‐2,3‐dienimidothioates (1‐aza‐1,3,4‐trienes) to give previously unknown thiophene‐2‐carboxylates and thiophene‐2‐carbonitriles, respectively, both bearing pyrrole substituents.
A Novel Sensitive Electrochemical Sensor Based on Nickel Chloride Solution Modified Glassy Carbon Electrode for Curcumin Determination
Authors: Zokhtareh Rosan , Rahimnejad Mostafa
Published: February 2018

In this research, the high conductivity of nickel chloride solution as well as the ability of nickel ions in establishing particular bonds with curcumin was benefited to fabricate a new electrochemical sensor based on nickel chloride solution modified glassy carbon electrode (NiCl2/GCE) for detection and measurement of curcumin in human blood serum. Atomic force microscope (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods indicated that using nickel chloride solution for the modification of the glassy carbon electrode (GCE) surface had a significant effect on improvement of the electrode performance. Differential pulse voltammetry (DPV) was used for quantitative measurement of curcumin, which exhibited the linear response of NiCl2/GCE toward curcumin within the concentration range of 10–600 μM and provided the detection limit of 0.109 μM for curcumin in human blood serum.
Glycosphingolipidomics of donkey milk by hydrophilic interaction liquid chromatography coupled to ESI and multistage MS
Authors: Calvano Cosima Damiana , Glaciale Marco , Palmisano Francesco , Cataldi Tommaso R.I.
Published: February 2018

Hydrophilic interaction liquid chromatography coupled to negative‐ion electrospray linear ion‐trap multiple‐stage MS (HILIC‐ESI‐MSn, n = 2,3) was used to characterize polar lipids occurring in donkey milk. Besides the detection of abundant phospholipids, the structural characterization and content evaluation of minor glycosphingolipids (GSLs) were assessed. We report an unprecedented characterization of 11 hexosyl‐ceramides (HexCer), 10 Hex2Cer, and 4 Hex3Cer. CID–MS/MS spectra in negative ion mode mainly afford information on the monosaccharide number and ceramide constitution (i.e., N‐acyl residue and long‐chain base), whereas MS/MS/MS spectra on the ceramide anions allow to recognize for each GSL the sphingoid base. The occurrence of sphingosine (S), sphinganine (DS), and phytosphingosine (P) was inferred from the fragmentation patterns. The milk samples exhibit a relatively high number of phytosphingosine substitutes, perhaps because of the feeding of donkeys, mainly based on pasture grass. However, the incidence of hydroxylated species on the α‐carbon of the acyl chain was also revealed. The fatty acid composition of N‐acyl chains showed high values of long‐chain saturated fatty acids such as 20:0, 22:0, 23:0, and 24:0. An average content of GSL is also provided and three representative mono‐, di‐, and tri‐HexCer in donkey milk are the following: HexCer 18:0/24:1 phytosphingosine nonhydroxylated [PN] at m/z 862.6 as chloride adduct [M+Cl]−, and content 225.9 ± 2.8 μg 100 mL−1; Hex2Cer 18:0/16:0 sphinganine nonhydroxylated [DSN] at m/z 862.7 as deprotonated adduct [M‐H]−, and content 70.8 ± 1.4 μg 100 mL−1; and Hex3Cer 18:1/24:1 [SN] at m/z 1132.8 as [M‐H]−, and content 38.5 ± 0.7 μg 100 mL−1.
Catalytic Transfer Hydrogenation of Furfural for the Production of Ethyl Levulinate: Interplay of Lewis and Brønsted Acidities
Authors: Tang Kan , Xie Shaoqu , Cofield Gabriel Ross , Yang Xiaokun , Tian Emmy , Lin Hongfei
Published: February 2018

Ethyl levulinate is sought after due to its applications as a fuel additive in biodiesel fuels. Currently it's industrially produced using harmful, highly reactive acids like H2SO4 and HCl, which are used to produce levulinic acid, the common precursor used for EL production. Herein, ethyl levulinate is produced from the synergistic effect of Brønsted and Lewis acids, which catalyze the hydrogenation of furfural leading to the alternative precursor for EL production, furfuryl alcohol. The subsequent ethanolysis reaction of furfuryl alcohol to produce EL, is also enhanced by using an optimal ratio of Brønsted to Lewis acids. Ethanol is chosen as the sacrificial hydrogen donor for proton transfer hydrogenation since it is environmentally friendly, more abundant and affordable than other alcohols that are commonly used for large‐scale production processes. The tandem catalytic reaction can be effectively used to sustainably and responsibly produce ethyl levulinate in relatively short reaction times.
Separation of polyaromatic hydrocarbons from model diesel composition via pervaporation using a fabricated aromatic polyimide membrane and process optimization
Authors: Roychowdhury Sayan , Mitra Debarati
Published: February 2018

Removal of polyaromatics from diesel is important to meet automobile emission specifications. According to Worldwide Fuel Charter, the maximum allowable concentration of polyaromatic hydrocarbons (PAHs) in automotive diesel should be less than 2% vol (max). An aromatic polyimide membrane was fabricated by solution casting a mixture of polyamic acid, N,N‐dimethylacetamide and phenanthrene. This membrane was utilized for the separation of a multicomponent mixture consisting of acenaphthene and 2‐methyl naphthalene (PAHs) in toluene and n‐tetradecane, chosen as model diesel composition via pervaporation. The prepared membrane was characterized by mechanical strength testing, SEM and TGA‐DTA study. The influence of varying downstream pressure, feed composition, and operating temperature on the pervaporative separation performance in terms of combined permeation flux of the PAHs was investigated. A central composite experimental design along with response surface methodology was conducted to optimize these process factors for maximizing the combined permeation flux. The maximum value of combined permeation flux obtained was 0.071 kg m−2 h−1. Hence, it can be concluded that the novel membrane fabricated using a simple and relatively inexpensive method has good potentiality for pervaporative removal of PAHs from the chosen system. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018
A secure lightweight signature based authentication for Cloud‐IoT crowdsensing environments
Authors: Kumar Manoj , Verma Harsh Kumar , Sikka Geeta
Published: February 2018

Crowdsensing utilizes the wisdom of crowd by sensing the information through different types of smart devices such as a smartphone, tablet, and sensors to serve the problem of common interests. It can be achieved by the concept of Internet of Things (IoT), which considers a large set of smart sensing interconnected devices. However, these devices are resource constrained in terms of storage, infrastructure, and computation power, and therefore, cloud technology is required. In order to minimize the storage overhead, only authentic extracted information from crowdsourcing is desirable to store in the cloud space. A number of signature‐based authentication schemes have been designed using either bilinear pairing or random oracle model (ROM) for the IoT devices. However, due to the high computational pairing cost and improper ROM implementation, schemes are found to be inefficient and vulnerable under the chosen‐message and chosen‐ID attack. To reduce the computational cost, we propose a pairing‐free quadratic residue–based signature scheme that authenticates IoT devices and cloud centric data. In addition, the proposed signature does not consider ROM, and it is secure in the standard model based on the proposed modified interactive quadratic residuosity assumption. Performance evaluation and comparisons ensure that our scheme is more efficient than earlier related schemes.
Centralization errors in comparative genomic hybridization array analysis of pituitary tumor samples
Authors: Lasolle Hélène , Alix Eudeline , Bonnefille Clément , Elsensohn Mad‐Hélénie , Michel Jessica , Sanlaville Damien , Roy Pascal , Raverot Gérald , Bardel Claire
Published: February 2018

Reliable interpretation of comparative genomic hybridization array (aCGH) results requires centralization and normalization of the data. We evaluated the reliability of aCGH centralization by comparing aCGH results (with classical centralization‐normalization steps) to fluorescence in situ hybridization (FISH) results. In addition, we propose a method to correct centralization bias. Sixty‐six pituitary tumors were analyzed (Agilent aCGH + SNP 4 × 180K microarray). For each tumor, the FISH‐based log2(ratios) of a subset of chromosomes were compared with the corresponding aCGH raw log2(ratios). With our new normalization‐centralization process, this difference was added to all log2(ratios), before performing loess regression on non‐altered probes only. Finally, the mean log2(ratio) and the percentage of normal probes were compared between CGHnormaliter and our new FISH‐based method. For 11 tumors, FISH results and raw CGH log2(ratios) differed significantly. In addition, nine tumors showed discrepancies between results generated by CGHnormaliter and our new‐method. Such discrepancies seemed to occur with tumours with many abnormalities (0%‐40% normal probes), rather than in those tumours with fewer abnormalities (31%‐100% normal probes). Five tumors had too few normal probes to allow normalization. In these tumors, which can exhibit many changes in DNA copy number, we found that centralization bias was frequent and uncorrected by current normalization methods. Therefore, an external control for centralization, such as FISH analysis, is required to insure reliable interpretation of aCGH data.
Mapping and characterization of positive and negative BOLD responses to visual stimulation in multiple brain regions at 7T
Authors: Jorge João , Figueiredo Patrícia , Gruetter Rolf , van der Zwaag Wietske
Published: February 2018

External stimuli and tasks often elicit negative BOLD responses in various brain regions, and growing experimental evidence supports that these phenomena are functionally meaningful. In this work, the high sensitivity available at 7T was explored to map and characterize both positive (PBRs) and negative BOLD responses (NBRs) to visual checkerboard stimulation, occurring in various brain regions within and beyond the visual cortex. Recently‐proposed accelerated fMRI techniques were employed for data acquisition, and procedures for exclusion of large draining vein contributions, together with ICA‐assisted denoising, were included in the analysis to improve response estimation. Besides the visual cortex, significant PBRs were found in the lateral geniculate nucleus and superior colliculus, as well as the pre‐central sulcus; in these regions, response durations increased monotonically with stimulus duration, in tight covariation with the visual PBR duration. Significant NBRs were found in the visual cortex, auditory cortex, default‐mode network (DMN) and superior parietal lobule; NBR durations also tended to increase with stimulus duration, but were significantly less sustained than the visual PBR, especially for the DMN and superior parietal lobule. Responses in visual and auditory cortex were further studied for checkerboard contrast dependence, and their amplitudes were found to increase monotonically with contrast, linearly correlated with the visual PBR amplitude. Overall, these findings suggest the presence of dynamic neuronal interactions across multiple brain regions, sensitive to stimulus intensity and duration, and demonstrate the richness of information obtainable when jointly mapping positive and negative BOLD responses at a whole‐brain scale, with ultra‐high field fMRI.
Bax inhibitor‐1 protects from nonalcoholic steatohepatitis by limiting inositol‐requiring enzyme 1 alpha signaling in mice
Authors: Lebeaupin Cynthia , Vallée Déborah , Rousseau Déborah , Patouraux Stéphanie , Bonnafous Stéphanie , Adam Gilbert , Luciano Frederic , Luci Carmelo , Anty Rodolphe , Iannelli Antonio , Marchetti Sandrine , Kroemer Guido , Lacas‐Gervais Sandra , Tran Albert , Gual Philippe , Bailly‐Maitre Béatrice
Published: February 2018

Endoplasmic reticulum (ER) stress is activated in nonalcoholic fatty liver disease (NAFLD), raising the possibility that ER stress‐dependent metabolic dysfunction, inflammation, and cell death underlie the transition from steatosis to steatohepatitis (nonalcoholic steatohepatitis; NASH). B‐cell lymphoma 2 (BCL2)‐associated X protein (Bax) inhibitor‐1 (BI‐1), a negative regulator of the ER stress sensor, inositol‐requiring enzyme 1 alpha (IRE1α), has yet to be explored in NAFLD as a hepatoprotective agent. We hypothesized that the genetic ablation of BI‐1 would render the liver vulnerable to NASH because of unrestrained IRE1α signaling. ER stress was induced in wild‐type and BI‐1
–/– mice acutely by tunicamycin (TM) injection (1 mg/kg) or chronically by high‐fat diet (HFD) feeding to determine NAFLD phenotype. Livers of TM‐treated BI‐1
–/– mice showed IRE1α‐dependent NOD‐like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation, hepatocyte death, fibrosis, and dysregulated lipid homeostasis that led to liver failure within a week. The analysis of human NAFLD liver biopsies revealed BI‐1 down‐regulation parallel to the up‐regulation of IRE1α endoribonuclease (RNase) signaling. In HFD‐fed BI‐1
–/– mice that presented NASH and type 2 diabetes, exaggerated hepatic IRE1α, X‐box binding protein 1 (XBP1), and C/EBP homologous protein (CHOP) expression was linked to activated NLRP3 inflammasome and caspase‐1/‐11. Rises in interleukin (IL)‐1β, IL‐6, monocyte chemoattractant protein 1 (MCP1), chemokine (C‐X‐C motif) ligand 1 (CXCL1), and alanine transaminase (ALT)/aspartate transaminase (AST) levels revealed significant inflammation and injury, respectively. Pharmacological inhibition of IRE1α RNase activity with the small molecules, STF‐083010 or 4μ8c, was evaluated in HFD‐induced NAFLD. In BI‐1
–/– mice, either treatment effectively counteracted IRE1α RNase activity, improving glucose tolerance and rescuing from NASH. The hepatocyte‐specific role of IRE1α RNase activity in mediating NLRP3 inflammasome activation and cell death was confirmed in primary mouse hepatocytes by IRE1α axis knockdown or its inhibition with STF‐083010 or 4μ8c. Conclusion: Targeting IRE1α‐dependent NLRP3 inflammasome signaling with pharmacological agents or by BI‐1 may represent a tangible therapeutic strategy for NASH. (Hepatology 2018).
New scoring classification for primary biliary cholangitis–autoimmune hepatitis overlap syndrome
Authors: Zhang Wei , De Debapriya , Mohammed Kahee A. , Munigala Satish , Chen Guilan , Lai Jin‐Ping , Bacon Bruce R.
Published: February 2018

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are two major immune‐mediated chronic liver diseases. Overlap syndrome (OS) is diagnosed if patients have features of both AIH and PBC; however, there is no consensus on the definition or diagnostic criteria for OS. Here, we report a new scoring classification for OS and evaluate its usefulness. This new scoring classification was developed by modifying the International Autoimmune Hepatitis Group classification by selecting histologic features of AIH and PBC along with modifications of biochemical and immunologic characteristics. We evaluated 272 patients with chronic liver disease, including 105 with AIH, 102 with PBC, and 65 with OS. The best performance for the diagnosis of OS was noted among patients with an overlap score of ≥21 who had a sensitivity of 98.5%, a specificity of 92.8%, a positive predictive value of 81.0%, and a negative predictive value of 99.5%. By using a cut‐off score of 21, 64 (98.5%) patients were diagnosed with OS as opposed to 9 (8.8%) and 6 (5.7%) with PBC and AIH, respectively. All patients with OS had an aggregate score of >19, whereas most patients with PBC or AIH scored <19, making this a safe discriminatory cut‐off point against OS. Conclusion: The new scoring system for the diagnosis of OS has a high sensitivity and specificity for scores ≥21, while a score <19 suggests a diagnosis other than OS. This classification can identify patients and diagnose OS with a reasonable amount of accuracy and may be superior to current OS scoring systems in detecting mild forms of OS. (Hepatology Communications 2018;2:245‐253)
A graphical approach for documenting peatland hydrodiversity and orienting land management strategies
Authors: Rosa Eric , Dallaire Pierre‐Luc , Nadeau Simon , Cloutier Vincent , Veillette Jean , van Bellen Simon , Larocque Marie
Published: February 2018

This study focuses on the development of an approach to document the hydrological characteristics of peatlands and understand their potential influence on runoff processes and groundwater flow dynamics. Spatial calculations were performed using geographic information systems data in order to evaluate the distribution of peatlands according to (a) neighbouring hydrogeological units and (b) their position within the hydrographic network. The data obtained from these calculations were plotted in a multiple trilinear diagram (two ternary plots projected into a diamond‐shaped diagram) that illustrates the position of a given peatland within the hydrogeological environment. The data allow for the segregation of peatlands according to groups sharing similarities as well as the identification of peatlands that are most likely to have similar hydrological functions. The approach was tested in a 19,549 km2 region of the southern portion of the Barlow‐Ojibway Clay Belt (in Abitibi‐Témiscamingue, Canada) and lead to a conceptual model representing the hydrological interactions between peatlands, aquifers, and surface waters. This approach allows for a geographic information systems‐based differentiation of headwater peatland complexes that are likely to interact with aquifers and to supply continuous baseflow to small streams from lowland peatland complexes of the clay plain that are isolated from surrounding aquifers but that can act as storage reservoirs within the hydrographic network. The typology is further used to discuss land management strategies aimed at preserving peatland hydrodiversity within the study region. The proposed approach relies on widely applicable hydrogeological and hydrographic criteria and provides a tool that could be used for assessing peatland hydrodiversity in other regions of the planet.