bluuebunny/crossref_metadata_2025 huggingface dataset:
Ionic Conductivity of the NASICON‐Related Thiophosphate Na1+xTi2−xGax(PS4)3
Authors: Schlem Roman , Till Paul , Weiss Manuel , Krauskopf Thorben , Culver Sean P. , Zeier Wolfgang G.
Published: January 2019

Inspired by the recent interest in fast ionic conducting solids for electrolytes, the ionic conductivity of a novel ionic conductor Na1+xTi2−xGax(PS4)3 has been investigated. Using X‐ray diffraction and impedance spectroscopy the sodium ionic conductivity in this compound was demonstrated, in which bond valence sum analysis suggests a tunnel diffusion for Na+. Substitution with Ga3+ leads to an increasing Na+ content, an expansion of the lattice and an increasing conductivity with increasing x in Na1+xTi2−xGax(PS4)3. Given the relation to the NASICON family, upon replacement of the phosphate by a thiophosphate group, a rich structural chemistry can be expected in this class of materials. This work demonstrates the potential for making NaTi2(PS4)3 an ideal system to study structure‐property relationships in ionic conductors.
Direct Conversion of Benzothiadiazole to Benzimidazole: New Benzimidazole‐Derived Metal–Organic Frameworks with Adjustable Honeycomb‐Like Cavities
Authors: Zhao Yingnan , Han Xiao , Yu Feihu , Wei Donghui , Cheng Qing , Meng Xiangru , Ding Jie , Hou Hongwei
Published: February 2019

Up to now, the direct conversion of the thiadiazole ring to other heterocyclic rings has been a very challenging task. Herein, a CdII‐mediated alcohol‐substitution strategy for direct conversion from benzothiadiazole to benzimidazole is reported. Experimental and molecular modeling studies on the role of the chelated metal ion in this in situ alcohol‐substitution reaction revealed that it serves as an all‐rounder that is involved in the insertion of alcohol, activation of the thiadiazole ring by coordinative interaction, and the sulfur‐extrusion process. Interestingly, the insertion of alcohol occurs much earlier than the sulfur‐extrusion process, supported by a water‐mediated proton‐transfer process. This strategy also is suitable for constructing new benzimidazole‐derived MOFs [Cd2(HMBIDC2−)2]⋅4 H2O (Cd‐BID‐MOF‐1, HMBIDC2−=2‐methyl‐1H‐benzimidazole‐4,7‐dicarboxylate) and [Cd2(HPBIDC2−)2]⋅1/3 H2O (Cd‐BID‐MOF‐2, HPBIDC2−=2‐(3‐hydroxypropyl)‐2H‐benzimidazole‐4,7‐dicarboxylate). Because the terminal hydroxyl group on the imidazole ring protrudes into the circular channel in rhombohedral Cd‐BID‐MOF‐2, the cavity is closer to hydrophilic than the honeycomb‐like cavity in Cd‐BID‐MOF‐1 with similar 3D structure. This rare observation will provide a new strategy to develop in situ ligand‐reaction synthesis of functional MOFs and useful chelation‐assisted catalytic reactions in heteroaromatic chemistry.
Boosting Molecular Complexity with O2: Iron‐Catalysed Oxygenation of 1‐Arylisochromans through Dehydrogenation, Csp3−O Bond Cleavage and Hydrogenolysis
Authors: Gonzalez‐de‐Castro Angela , Robertson Craig M. , Xiao Jianliang
Published: February 2019

Oxidative cleavage of the Csp3−O bond in 1‐arylisochromans with stoichiometric oxidants, such as CrO3/H2SO4, has been practiced for decades in synthetic chemistry. Herein, we report that a structurally well‐defined FeII–pyridyl(bis‐imidazolidine) catalyst promotes the aerobic oxygenation of 1‐arylisochromans, affording highly selectively 2‐(hydroxyethyl)benzophenones, compounds of potential for neuroprotective agents. Key intermediates have been isolated, indicating that the reaction proceeds through dehydrogenative oxygenation of the isochromans at the 1‐position, Csp3−O bond cleavage at the iron centre and hydrogenolysis of the resulting Fe−O bond with the H2generated from the dehydrogenation step. In the absence of H2but under iron catalysis, the peroxide intermediate is converted into an unexpected ketal compound, which transfers into a 2‐(hydroxyethyl)benzophenone when both O2and H2are admitted. The unique ability of the iron catalyst for oxygenation and hydrogenation in the same catalytic process under mild conditions allows for the stepwise preparation of a variety of isolable oxygenated products on a preparative scale, circumventing the need for using wasteful and/or toxic oxidants.
Chemoenzymatic Cascade Synthesis of Optically Pure Alkanoic Acids by Using Engineered Arylmalonate Decarboxylase Variants
Authors: Enoki Junichi , Mügge Carolin , Tischler Dirk , Miyamoto Kenji , Kourist Robert
Published: January 2019

Arylmalonate decarboxylase (AMDase) catalyzes the cofactor‐free asymmetric decarboxylation of prochiral arylmalonic acids and produces the corresponding monoacids with rigorous R selectivity. Alteration of catalytic cysteine residues and of the hydrophobic environment in the active site by protein engineering has previously resulted in the generation of variants with opposite enantioselectivity and improved catalytic performance. The substrate spectrum of AMDase allows it to catalyze the asymmetric decarboxylation of small methylvinylmalonic acid derivatives, implying the possibility to produce short‐chain 2‐methylalkanoic acids with high optical purity after reduction of the nonactivated C=C double bond. Use of diimide as the reductant proved to be a simple strategy to avoid racemization of the stereocenter during reduction. The developed chemoenzymatic sequential cascade with use of R‐ and S‐selective AMDase variants produced optically pure short‐chain 2‐methylalkanoic acids in moderate to full conversion and gave both enantiomers in excellent enantiopurity (up to 83 % isolated yield and 98 % ee).
Rare‐Earth‐Metal Pentadienyl Half‐Sandwich and Sandwich Tetramethylaluminates–Synthesis, Structure, Reactivity, and Performance in Isoprene Polymerization
Authors: Barisic Damir , Buschmann Dennis A. , Schneider David , Maichle‐Mössmer Cäcilia , Anwander Reiner
Published: February 2019

Targeting the synthesis of rare‐earth‐metal pentadienyl half‐sandwich tetramethylaluminate complexes, homoleptic [Ln(AlMe4)3] (Ln=Y, La, Ce, Pr, Nd, Lu) were treated with equimolar amounts of the potassium salts K(2,4‐dmp) (2,4‐dmp=2,4‐dimethylpentadienyl), K(2,4‐dipp) (2,4‐dipp=2,4‐diisopropylpentadienyl), and K(2,4‐dtbp) (2,4‐dtbp=2,4‐di‐tert‐butylpentadienyl). The reactions involving the larger rare‐earth‐metal centers lanthanum, cerium, praseodymium, and neodymium gave selectively the desired half‐sandwich complexes [(2,4‐dmp)La(AlMe4)2], [(2,4‐dipp)La(AlMe4)2], and [(2,4‐dtbp)Ln(AlMe4)2] (Ln=La, Ce, Pr, Nd) in high crystalline yields. Smaller rare‐earth‐metal centers yielded preferentially the sandwich complexes [(2,4‐dmp)2Ln(AlMe4)] (Ln=Y, Lu) and [(2,4‐dipp)2Y(AlMe4)]. Activation with fluorinated borate/borane co‐catalysts gave highly active catalyst systems for the fabrication of polyisoprene, displaying molecular weight distributions as low asMw/Mn=1.09 and a maximumcis‐1,4 selectivity of 90.4 %. The equimolar reaction of half‐sandwich complex [(2,4‐dtbp)La(AlMe4)2] with B(C6F5)3led to the isolation and full characterization of the single‐component catalyst {{(2,4‐dtbp)La[(μ‐Me)2AlMe(C6F5)]}[Me2Al(C6F5)2]}2. The reaction of the latter complex with 10 equivalents of isoprene could be monitored by1H NMR spectroscopy. Also, a donor‐induced aluminato/gallato exchange was achieved with [(2,4‐dtbp)La(AlMe4)2] and GaMe3(OEt2) leading to [(2,4‐dtbp)La(GaMe4)2].
Enantioselective Synthesis of the Platensimycin Core by Silver(I)‐Promoted Cyclization of Δ6‐α‐Iodoketone
Authors: Trajkovic Milos , Ferjancic Zorana , Saicic Radomir N. , Bihelovic Filip
Published: February 2019

A chiral‐pool‐based synthesis of the platensimycin core was achieved using (S)‐lactic acid as an inexpensive starting material. The cyclohexenone ring was closed in a Mukaiyama–Michael domino sequence, while the quaternary stereocenter was created by a highly stereoselective decarboxylative allylation. The spirobicyclic skeleton was constructed by a RCM reaction. A new silver(I)‐promoted cyclization reaction of Δ6‐ and Δ7‐α‐iodoketones was developed and applied for the pivotal carbon–carbon bond formation. The scope and limitations of this methodology are also presented.
Design, synthesis and application of chiral tetraoxacalix[2]arene[2]triazine‐based organocatalysts in asymmetric Michael addition reactions
Authors: Genc Hayriye Nevin , Ozgun Ummu , Sirit Abdulkadir
Published: January 2019

A novel type of oxacalix[2]arene[2]triazine‐based organocatalysts for asymmetric Michael reactions are reported for the first time. Chiral subunits were attached to the heteroatom‐bridged calixaromatic platform by a reaction of (R)‐ and (S)‐1‐aminotetraline with tetraoxacalix[2]arene[2]triazine in both enantiomeric forms. To evaluate the catalytic efficiency of the novel organocatalysts, isobutyraldehyde reacted with various substituted and unsubstituted aromatic trans‐β‐nitrostyrenes in tetrahydrofuran (THF), leading to Michael adducts in excellent yields and enantioselectivites (up to 97% yield and 99% ee).
Rigidity and Edge Universality of Discrete β‐Ensembles
Authors: Guionnet Alice , Huang Jiaoyang
Published: February 2019

We study discrete β‐ensembles as introduced in [17]. We obtain rigidity estimates on the particle locations; i.e., with high probability, the particles are close to their classical locations with an optimal error estimate. We prove the edge universality of the discrete β‐ensembles; i.e., for β ≥ 1, the distribution of extreme particles converges to the Tracy‐Widom β‐distribution. As far as we know, this is the first proof of general Tracy‐Widom β‐distributions in the discrete setting. A special case of our main results implies that under the Jack deformation of the Plancherel measure, the distribution of the lengths of the first few rows in Young diagrams converges to the Tracy‐Widom β‐distribution, which answers an open problem in [38]. Our proof relies on Nekrasov's (or loop) equations, a multiscale analysis, and a comparison argument with continuous β‐ensembles. © 2019 Wiley Periodicals, Inc.
pH Controlled Intersystem Crossing and Singlet Oxygen Generation of 8‐Azaadenine in Aqueous Solution
Authors: Zhou Zhongneng , Hu Zhubin , Zhang Xianwang , Jia Menghui , Wang Xueli , Su Hongmei , Sun Haitao , Chen Jinquan , Xu Jianhua
Published: January 2019

Azabases are intriguing DNA and RNA analogues and have been used as effective antiviral and anticancer medicines. However, photosensitivity of these drugs has also been reported. Here, pH‐controlled intersystem crossing (ISC) process of 9H 8‐azaadenine (8‐AA) in aqueous solution is reported. Broadband transient absorption measurements reveal that the hydrogen atom at N9 position can greatly affect ISC of 8‐AA and ISC is more favorable when 8‐AA is in its neutral form in aqueous solution. The initial excited ππ* (S2) state evolves through ultrafast internal conversion (IC) (4.2 ps) to the lower‐lying nπ* state (S1), which further stands as a door way state for ISC with a time constant of 160 ps. The triplet state has a lifetime of 6.1 μs. On the other hand, deprotonation at N9 position promotes the IC from the ππ* (S2) state to the ground state (S0) and the lifetime of the S2 state is determined to be 10 ps. The experimental results are further supported by time‐dependent density functional theory (TDDFT) calculations. Singlet oxygen generation yield is measured to be 13.8 % for the neutral 8‐AA while the deprotonated one exhibit much lower yield (<2 %), implying that this compound could be a potential pH‐sensitized photodynamic therapy agent.
Ion Mobility Mass Spectrometric Investigation on the Photoisomerization of a 4,4’‐Diamidoazobenzene Model
Authors: Wollschläger Jan M. , Schalley Christoph A.
Published: February 2019

The photoisomerization of a new 4,4′‐diamidoazobenzene model is investigated with ion mobility mass spectrometry. Taking observations of previous studies and new control experiments into consideration, a mechanism for a fast thermal (Z)→(E) isomerization of azobenzenes during ionization is proposed. The experiments clearly show that a fast (Z)→(E) isomerization is operative when the azo group is protonated, while it can be prevented when another protonation site remote from the azo group is offered. Besides this, the peak integration ratio in the ion mobilogram is shown to closely correlate with the photoisomer ratio in solution. Future prospects for applications in photocatalysis and systems chemistry are discussed.
Inducing a Mucosal Barrier–Sparing Inflammatory Response in Laboratory‐Grown Primary Human Nasal Epithelial Cells
Authors: Ramezanpour Mahnaz , Bolt Harrison , Psaltis Alkis , Wormald Peter‐John , Vreugde Sarah
Published: February 2019

Here we use the toll‐like receptor (TLR) 3 agonist poly I:C (LMW) to induce an inflammatory response in cells of submerged and/or air‐liquid interface (ALI) cultures of human nasal epithelial cells (HNECs). The inflammatory response is determined by measuring interleukin‐6 (IL‐6) protein levels by enzyme‐linked immunosorbent assay (ELISA). The mucosal barrier integrity is determined by measuring transepithelial electrical resistance (TEER) and passage of fluorescently labeled dextrans. Stimulation with poly (I:C) LMW induces a 15‐ to 17‐fold increase in IL‐6 production by HNEC‐ALI cells. © 2019 by John Wiley & Sons, Inc.
The effect of magnetic field on plasma particles in dusty plasma
Authors: Karasev V.Yu. , Dzlieva E.S. , D'yachkov L.G. , Novikov L.A. , Pavlov S.I. , Tarasov S.A.
Published: February 2019

In this work, we present the investigation of the formation features and internal structure of dust clouds created in plasma of glow discharge in the external magnetic field corresponding to a range of moderate and strong fields, at which the ion component is magnetized. The analysis of the plasma magnetization in the presence of dust components is carried out. We defined the values of magnetic induction at which the changes in dynamics of plasma particles in magnetic field in light inert gases are expected. The experimental setup was built in two versions. For the purpose of generating of magnetic field, the first setup was equipped with ordinary magnetic coils, and the second one included a superconducting solenoid. The discharge tubes, the main chambers where plasma was ignited and maintained in a glow discharge in lowered pressure, also have certain peculiarities, which we describe below. While using helium as a bulk gas, our study focused only on the dust trap in the region of narrowing discharge current. For neon, we used two traps: the striation trap and one just mentioned above placed in the narrowing of the discharge tube. As a result, the steady dust structures in a glow discharge under the magnetization of ions and electrons were obtained for the first time. Dust structures were rotated and tended to form a dust cluster and shell structure. A number of parameters of magnetization achieved in experiments were calculated.
FxCycle™ Based Ploidy Correlates with Cytogenetic Ploidy in B‐Cell Acute Lymphoblastic Leukemia and Is Able to Detect the Aneuploid Minimal Residual Disease Clone
Authors: Gupta Nishit , Parihar Mayur , Banerjee Sambhunath , Brahma Subhajit , Pawar Ravikiran , Rath Asish , Shewale Sundar , Singh Manish , Sasikumaran Nair Remani Arun , Krishnan Shekhar , Bhatacharyya Arpita , Das Anirban , Kumar Jeevan , Bhave Saurabh , Radhakrishnan Vivek , Nair Reena , Chandy Mammen , Mishra Deepak , Arora Neeraj
Published: February 2019

Background

Flow cytometry (FCM) is a simple, sensitive, and specific technique that can potentially determine DNA ploidy in B‐cell precursor ALL (BCP‐ALL) and is complementary to cytogenetics.

Methods

A prospective FCM DNA ploidy analysis using FxCycle™ Violet (assay sensitivity 0.01%) was done in 125 consecutive new cases of BCP‐ALL (90 cases <15 years of age) and compared with corresponding cytogenetic ploidy (karyotyping and/or FISH) data wherever available. This assay was also subsequently evaluated for detection of residual aneuploid clone in few BCP‐ALL cases.

Results

Of the total 125 BCP‐ALL cases evaluated, flow ploidy analysis revealed diploidy (DI 0.96–1.05) in 44.8% (n= 56), low‐hyperdiploidy (DI 1.06 to 1.15) in 13.6% (n= 17), high‐hyperdiploidy (DI 1.16–1.39) in 32.8% (n= 41) and near‐tetraploidy (DI ≥ 1.80) in 2.4% (n= 3) cases. The high risk sub‐group of low‐hypodiploidy (DI 0.70 to 0.88)/near‐triploidy (DI 1.40 to 1.79) constituted 5.6% (n= 7) cases while there was only one case with haploidy (DI 0.58). Overall, high concordance of 90.4% (n= 113) was noted between the combined cytogenetics ploidy and FCM ploidy. Of the total discordant cases (n= 12), the maximum discordance was seen in the low‐hyperdiploid DI subgroup (n= 10), which included seven cases with low DNA index high hyperdiploidy (LDI‐HHD). FCM DNA ploidy assay was able to detect the residual clone in all six MRD positive aneuploid cases evaluated.

Conclusions

FxCycle™ based DNA ploidy ascertains strong correlation with cytogenetic profiles and yields complementary information that can be used by the cytogenetics laboratories or otherwise. © 2019 International Clinical Cytometry Society
Obesity and its cardiovascular effects
Authors: Ortega‐Loubon Christian , Fernández‐Molina Manuel , Singh Gauri , Correa Ricardo
Published: February 2019

Obesity is described in terms of body fat percentage or body mass index (BMI), despite the fact that these measures do not give full insight about the body fat distribution. It is presently a consistently growing universal challenge since it has tripled in the last 10 years, killing approximately 28 million people each year. In this review, we aim to clarify the different results of obesity on the working and physiology of the cardiovascular system and to reveal changes in the obesity “paradox”—a variety of cardiovascular outcomes in typical/overweight people. Central fat build‐up in ordinary/overweight populaces has been related to expanded occurrences of myocardial infarction, heart failure, or all‐cause mortality when contrasted with the obese populace. These discoveries are additionally clarified as the abundance and prolonged vulnerability to free fatty acids (FFAs) in obesity. This has been believed to cause the myocardial substrate to move from glucose to FFAs digestion, which causes lipid gathering in cardiomyocytes, spilling over to other lean tissues, and prompting a general atherogenic impact. This cardiomyocyte lipid aggregation has been demonstrated to cause insulin resistance and cardiovascular hypertrophy, and to lessen the heart functions in general. There is a proof backing the fact that fat tissue is not only an energy reservoir, it also coordinates hormones and proinflammatory cytokines and deals with the energy transition of the body by putting away abundant lipids in diverse tissues.
Is stage of change enough? Confidence as a predictor of outcome in inpatient treatment for eating disorders
Authors: Iyar Megumi M. , Cox Daniel W. , Kealy David , Srikameswaran Suja , Geller Josie
Published: January 2019

Objective

While stage of change has been shown to be a robust predictor of eating disorder treatment outcome, little attention has been paid to the role of confidence. This study sought to better understand the role of confidence and the possible interaction it may have with stage of change in promoting eating disorder symptom change.

Method

Participants were adult women in inpatient treatment for eating disorders. They completed measures of motivation for change, which assessed precontemplation, action, confidence and internality (changing for oneself vs. others) and eating disorder symptom severity at pretreatment (N = 159) and posttreatment (n = 59). Only treatment completer analyses were used.

Results

Precontemplation and confidence had significant effects on pretreatment and posttreatment symptom severity, while action only had a significant effect on pretreatment symptoms. Confidence was shown to moderate relations between both measures of stage of change (i.e., precontemplation and action) and symptoms posttreatment. Follow‐up analyses indicated that high precontemplation was associated with poor outcome, irrespective of confidence, however, low precontemplation was associated with better outcome at high levels of confidence. The interaction between confidence and action was also significant at very high levels of confidence. That is, among individuals who had high action at baseline, those with low confidence had significantly poorer outcomes relative to those with high confidence.

Discussion

Findings indicate that stage of change and confidence are both important prognostic factors and suggest that early behavior change in the absence of confidence may not guarantee best outcomes in inpatient eating disorder treatment.
Menopausal status and disordered eating and body image concerns among middle‐aged women
Authors: Thompson Katherine A. , Bardone‐Cone Anna M.
Published: January 2019

Objective

Eating disorders are present among middle‐aged women, yet most eating disorder knowledge comes from adolescents and young adults. There is arguably a need for research specific to middle‐aged women and eating pathology. One biological factor that may contribute to eating disorder symptoms and is unique to middle‐aged women is menopause, given the changes in body shape and weight that direct women's bodies away from the young, thin beauty standard.

Method

This study explored group differences in disordered eating and body image by menopausal status. Participants were 310 middle‐aged women between the ages of 40 and 68. They completed an online survey about their menopausal status, disordered eating, and body image concerns. We compared disordered eating behaviors and attitudes across three groups: premenopausal women, perimenopausal women, and postmenopausal women.

Results

Results indicated no group differences on either disordered eating or body image concerns by menopausal status.

Discussion

These findings suggest the perimenopausal period may not be a window of vulnerability for women in general. Given these mixed findings, future research should examine moderators to determine when there are menopausal status group differences on eating pathology.
Independently evolved and gene flow‐accelerated pesticide resistance in two‐spotted spider mites
Authors: Shi Pan , Cao Li‐Jun , Gong Ya‐Jun , Ma Ling , Song Wei , Chen Jin‐Cui , Hoffmann Ary A. , Wei Shu‐Jun
Published: February 2019

Pest species are often able to develop resistance to pesticides used to control them, depending on how rapidly resistance can emerge within a population or spread from another resistant population. We examined the evolution of bifenazate resistance in China in the two‐spotted spider mite (TSSM) Tetranychus uticae Koch (Acari: Tetranychidae), one of the most resistant arthropods, by using bioassays, detection of mutations in the target cytb gene, and population genetic structure analysis using microsatellite markers. Bioassays showed variable levels of resistance to bifenazate. The cytb mutation G126S, which confers medium resistance in TSSM to bifenazate, had previously been detected prior to the application of bifenazate and was now widespread, suggesting likely resistance evolution from standing genetic variation. G126S was detected in geographically distant populations across different genetic clusters, pointing to the independent origin of this mutation in different TSSM populations. A novel A269V mutation linked to a low‐level resistance was detected in two southern populations. Widespread resistance associated with a high frequency of the G126S allele was found in four populations from the Beijing area which were not genetically differentiated. In this case, a high level of gene flows likely accelerated the development of resistance within this local region, as well as into an outlying region distant from Beijing. These findings, therefore, suggest patterns consistent with both local evolution of pesticide resistance as well as an impact of migration, helping to inform resistance management strategies in TSSM.
Nutrient acquisition strategies augment growth in tropical N2‐fixing trees in nutrient‐poor soil and under elevated CO2
Authors: Nasto Megan K. , Winter Klaus , Turner Benjamin L. , Cleveland Cory C.
Published: February 2019

Tropical forests play a dominant role in the global carbon (C) cycle, and models predict increases in tropical net primary productivity (NPP) and C storage in response to rising atmospheric carbon dioxide (CO2) concentrations. The extent to which increasing CO2 will enhance NPP depends in part on the availability of nitrogen (N) and phosphorus (P) to support growth. Some tropical trees can potentially overcome nutrient limitation by acquiring N via symbiotic dinitrogen (N2) fixation, which may provide a benefit in acquiring P via investment in N‐rich phosphatase enzymes or arbuscular mycorrhizal (AM) fungi. We conducted a seedling experiment to investigate the effects of elevated CO2 and soil nutrient availability on the growth of two N2‐fixing and two non‐N2‐fixing tropical tree species. We hypothesized that under elevated CO2 and at low nutrient availability (i.e., low N and P), N2 fixers would have higher growth rates than non‐N2 fixers because N2 fixers have a greater capacity to acquire both N and P. We also hypothesized that differences in growth rates between N2 fixers and non‐N2 fixers would decline as nutrient availability increases because N2 fixers no longer have an advantage in nutrient acquisition. We found that the N2 fixers had higher growth rates than the non‐N2 fixers under elevated CO2 and at low nutrient availability, and that the difference in growth rates between the N2 and non‐N2 fixers declined as nutrient availability increased, irrespective of CO2. Overall, N2 fixation, root phosphatase activity, and AM colonization decreased with increasing nutrient availability, and increased under elevated CO2 at low nutrient availability. Further, AM colonization was positively related to the growth of the non‐N2 fixers, whereas both N2 fixation and root phosphatase activity were positively related to the growth of the N2 fixers. Though our results indicate all four tree species have the capacity to up‐ or down‐regulate nutrient acquisition to meet their stoichiometric demands, the greater capacity for the N2 fixers to acquire both N and P may enable them to overcome nutritional constraints to NPP under elevated CO2, with implications for the response of tropical forests to future environmental change.
Recent Advances in Catalytic Enantioselective Rearrangement
Authors: Wu Hua , Wang Qian , Zhu Jieping
Published: February 2019

Among the fundamental chemical transformations in organic synthesis, rearrangement has been recognized as powerful and reliable reactions for the construction of carbon–carbon or carbon–heteroatom bonds. Benefiting from the advance of the novel catalytic system, catalyst design and activation mode, the chemistry of enantioselective rearrangements has experienced ever‐growing development recently and has been successfully used in the synthesis of chiral non‐racemic building blocks, natural products, and other valuable compounds. We present herein a survey of the recent development on the catalytic enantioselective rearrangement (from 2013 onward) organized according to the rearrangement type.
Synthesis of Diazanorcaradienes and 1,2‐Diazepines via the Tandem [4+2]‐Cycloaddition/Retro‐[4+2]‐Cycloaddition Reaction between Methoxycarbonylcyclopropenes and Dimethoxycarbonyltetrazine
Authors: Belyy Alexander Yu. , Levina Anastasia A. , Platonov Dmitry N. , Salikov Rinat F. , Medvedev Michael G. , Tomilov Yury V.
Published: February 2019

The reaction of di(methoxycarbonyl)tetrazine with substituted cycloprop‐2‐ene‐1‐carboxylates gives a series of 3,4‐diazanorcaradienes and 1,2‐diazepines. The influence of the nature of cyclopropenes and the reaction conditions on its selectivity was investigated. The addition of nucleophiles to norcaradienes was studied and a rare example of the “walk” rearrangement in this class of compounds was revealed.
Regioselective Synthesis of Symmetrical and Unsymmetrical Bis(heteroaryl)methane (BHM)‐Containing Amino Acids
Authors: Ali Rafat , Ahamad Mohd. Zisan , Singh Shalini , Haq Wahajul
Published: February 2019

The simple and straightforward method for the preparation of symmetrical bis(heteroaryl)methane (BHM)‐containing amino acids by the reaction of cyclic enecarbamate with heteroaromatics has been developed. The reaction goes in regioselective manner and we get only 3, 3′‐bis(heteroaryl)methane (BHM)‐containing amino acids. In addition to this synthesis, of unsymmetrical bisindolylmethane (BIM)‐containing amino acids is also reported. These symmetrical and unsymmetrical BIM‐containing amino acids are reported first time and are considered as bishomotryptophan derivatives, a biologically important homolog of tryptophan. These important monomers may serve as important tools for peptide design and engineering.
Dielectrophoretic trapping of single leukemic cells using the conventional and compact optical measurement systems
Authors: Sharifi Noghabi Hamideh , Soo Mandy , Khamenehfar Avid , Li Paul C.H.
Published: January 2019

Here, we report a microfluidic same‐single‐cell analysis to study the inhibition of multidrug resistance due to drug efflux on single leukemic cells. Drug efflux inhibition was investigated in the microfluidic chip using two different fluorescence detection systems, namely, a compact single‐cell bioanalyzer and the conventional optical detection system constructed from an inverted microscope and a microphotometer. More importantly, a compact signal generator was used to conduct dielectrophoretic cell trapping together with the compact SCB. By using the DEP force, a single acute myeloid leukemia cell was trapped in the cell retention structure of the chip. This allowed us to detect dye accumulation in the MDR leukemic cells in the presence of cyclosporine A (CsA). CsA and rhodamine 123 were used as the P‐glycoprotein inhibitor and fluorescent dye, respectively. The result showed that the Rh123 fluorescence signal in a single‐cell increased dramatically over its same‐cell control on both fluorescence detection systems due to the inhibition by CsA.
Highly Reversible Phase Transition Endows V6O13 with Enhanced Performance as Aqueous Zinc‐Ion Battery Cathode
Authors: Shan Lutong , Zhou Jiang , Zhang Wanying , Xia Chengtao , Guo Shan , Ma Xuemei , Fang Guozhao , Wu Xianwen , Liang Shuquan
Published: January 2019

Aqueous zinc‐ion batteries (ZIBs), with favorable merits of high security and low cost, have gained much interest in the energy storage field. However, their development is still in its infancy. Herein, V6O13 is investigated as aqueous ZIB cathodes with excellent Zn2+ storage performance, as compared with VO2 and V2O5. The intrinsic open structure of V6O13 with mixed‐valance states of vanadium (V4+/V5+) is favorable to enable fast Zn2+ ion diffusion and improved electronic conductivity, outperforming VO2 and V2O5. Significantly, the highly reversible phase transition of zinc vanadate (Zn0.25V2O5·H2O) can be detected during discharging, which enables the insertion of more Zn2+ ions into the host structure. As a result, V6O13 can exhibit enhanced electrochemical properties, including high capacity and excellent long‐term cyclability (206 mA h g−1 at 10 A g−1 after 3000 cycles).
Analysis of a reactive distillation process to recover tertiary amines and acid for use in a combined nickel extraction‐mineral carbonation process
Authors: Zappala Lauren C. , Balucan Reydick D. , Vaughan James , Steel Karen M.
Published: February 2019

A range of carbon capture, utilization, and storage (CCUS) technologies are under development to suit the needs of different geographies and industries. Nickel laterites are a form of naturally weathered ultramafic rock, which makes them a suitable feedstock for CCUS via mineral carbonation. The pH swing processes developed for mineral carbonation use acid and base in a similar manner to nickel laterite refining, thus there is an opportunity to integrate the two processes.

The success of pH swing processes is heavily dependent on the ability to regenerate the acid and base within the process and have low energy requirements. This contribution presents a pH swing nickel extraction‐mineral carbonation process, which uses triethylamine as the base and sulfuric acid, and reports results of regeneration experiments performed by distillation of triethylamine and sulfuric acid solutions.

From the studies, the optimal pH of the regenerated acid is approximately 2.5 and at this point a highly selective separation is achieved with 70% recovery of amine while removing 13% of the water. It is proposed that formation of triethylammonium bisulphate (Et3NH+HSO4−) limits the recovery of amine. Future studies will assess the leaching efficacy of the regenerated acid. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13141, 2019
Synergetic combination of H2Zr1PW12O40 and Sn‐Beta as potential solid acid catalyst for direct one‐step transformation of glucose to ethyl levulinate, a biofuel additive
Authors: Mulik Nagesh , Niphadkar Prashant , Bokade Vijay
Published: February 2019

Ethyl levulinate (EL) has found wide applications as chemicals and biofuel additives. Efficient catalytic conversion of abundantly available glucose to ELs over solid acid catalyst having optimum Brønsted (B) and Lewis (L) acidity is highly appreciated. Present work demonstrated, direct one‐step synthesis of EL from glucose over synergized Brønsted (H2Zr1PW12O40) and Lewis (Sn‐Beta) acid catalyst. H2Zr1PW12O40 is prepared by exchanging H+ of tungstophosphoric acid (H3PW12O40‐heteropolyacid) with Zr, improves the heterogeneity in polar medium by 50%. The combination of a physical mixture of H2Zr1PW12O40 + Sn‐Beta with 80:20 weight ratio was found to be optimum for the maximum EL yield formation of 54% from glucose at 180°C for 3 h, which is probably the highest than reported over the heterogeneous catalyst in ethanol medium. An optimal combination of B and L catalyst and its ratio is found to be crucial for the direct transformation of glucose to EL in one step. The present study also explored that this combined physical mixture of H2Zr1PW12O40 + Sn‐Beta can tolerate glucose concentration up to 30 g/L, which is probably the higher than reported. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019
What Political Settings Promote Renewable Energy Investments by Energy Utilities?—A Qualitative Comparative Analysis in Swiss Cantons
Authors: Schmid Benjamin , Bornemann Basil
Published: January 2019

Investment decisions by power utilities significantly shape sustainable energy systems. While it is known that different political factors influence investment decisions, the interaction of these factors remains unclear. Using a fuzzy set qualitative comparative analysis of 22 cases in 19 Swiss cantons, this study analyses which combinations of political conditions promote investment decisions by utilities in renewable energies. The analysis reveals the significance of different combinations of political conditions. High investments in renewable energies can be explained above all by political settings in which high administrative capacity is linked to ambitious policy goals, to the considerable power of a parliamentary pro‐ecology coalition or to non‐privatized utilities. The results support other findings on the importance of complex governance settings with hierarchical elements. They raise further questions about the precise mechanisms that mediate between political conditions and investment decisions of energy utilities, and the role of public administrations in this respect.
The Critical Juncture Concept’s Evolving Capacity to Explain Policy Change
Authors: Hogan John
Published: February 2019

This article examines the evolution of our understanding of the critical junctures concept. The concept finds its origins in historical intuitionalism, being employed in the context of path dependence to account for sudden and jarring institutional or policy changes. We argue that the concept and the literature surrounding it—now incorporating ideas, discourse, and agency—have gradually become more comprehensive and nuanced as historical institutionalism was followed by ideational historical institutionalism and constructivist and discursive institutionalism. The prime position of contingency has been supplanted by the role of ideas and agency in explaining critical junctures and other instances of less than transformative change. Consequently, the concept is now capable of providing more comprehensive explanations for policy change.
A Vitellogenin Antibody in Honey Bees (Apis mellifera): Characterization and Application as Potential Biomarker for Insecticide Exposure
Authors: Christen Verena , Vogel Maren Susanne , Hettich Timm , Fent Karl
Published: February 2019

The insect yolk precursor vitellogenin is a lipoglycoprotein synthesized and stored in the fat body and secreted into the hemolymph. In honey bees, vitellogenin displays crucial functions in hormone signaling, behavioral transition of nurse bees to foragers, stress resistance, and longevity in workers. Plant protection products such as neonicotinoids, pyrethroids, and organophosphates alter the transcriptional expression of vitellogenin. To assess plant protection product-induced alterations on the protein level, we developed a rabbit polyclonal vitellogenin antibody. After characterization, we assessed its specificity and vitellogenin levels in different tissues of worker bees. The vitellogenin antibody recognized full-length 180-kDa vitellogenin and the lighter fragment of 150 kDa in fat body, hemolymph, and brain. In hemolymph, a band of approximately 75 kDa was detected. Subsequent mass spectrometric analysis (liquid chromatography–mass spectrometry) confirmed the 180- and 150-kDa bands as vitellogenin. Subsequently, we evaluated vitellogenin expression in brain, fat body, and hemolymph on 24-h exposure of bees to 3 ng/bee to the neonicotinoid clothianidin. Full-length vitellogenin was upregulated 3-fold in the fat body, and the 150-kDa fragment was upregulated in the brain of exposed honey bees, whereas no alteration occurred in the hemolymph. Upregulation of the vitellogenin protein by the neonicotinoid clothianidin is in line with the previously shown induction of its transcript. We conclude that vitellogenin might serve as a potential biomarker for neonicotinoid and other pesticide exposure in bees. Environ Toxicol Chem 2019;00:1–10. © 2019 SETAC

Abstract

Vitellogenin: A pesticide biomarker?
Essential oils of Moldavian Thymus species: Chemical composition, antioxidant, anti‐Aspergillus and antigenotoxic activities
Authors: Aprotosoaie Ana Clara , Miron Anca , Ciocârlan Nina , Brebu Mihai , Roşu Crăiţa Maria , Trifan Adriana , Vochiţa Gabriela , Gherghel Daniela , Luca Simon Vlad , Niţă Alexandru , Costache Irina‐Iuliana , Mihai Cosmin Teodor
Published: January 2019

Thymus species are important aromatic, medicinal and culinary plants with a significant economic value. This study evaluated for the first time the chemical composition and in vitro bioactivities of the essential oils (EOs) from five Moldavian Thymus species (T. vulgaris, T. × citriodorus, T. calcareus) and cultivars (T. vulgaris ‘Faustini’, T. citriodorus ‘Aureus’). The main compounds in Thymus EOs were: thymol in T. vulgaris and T. calcareus EOs (55.44% and 55.45%, respectively), lavandulol in T. × citriodorus EO (54.27%), and geraniol in T. citriodorus ‘Aureus’ and T. vulgaris ‘Faustini’ EOs (60.31% and 31.45%, respectively). T. vulgaris and T. calcareus EOs showed the most potent antioxidant activities (EC50=0.003 mg/mL in ABTS radical cation scavenging assay) and exhibited significant inhibitory effects against aflatoxin‐producing Aspergillus flavus fungus (MIC=0.25 μL/mL). At doses that provided micromolar concentrations of thymol, T. vulgaris and T. calcareus EOs acted genoprotective at preventive and interventional levels against H2O2‐induced genomic damage in V79 cells, the former being more active (6.21% and 5.52% vs. 25.13% and 7.26% tail DNA in pre‐ and post‐treatment protocols, respectively). The genoprotective effects may be ascribed to antioxidant potential and, possibly, to stimulation of DNA repair processes. The Moldavian Thymus species are valuable resources of bioactive EOs for pharmaceutical and food industries (T. vulgaris, T.calcareus) but also for flavor industry and perfumery (T. × citriodorus, T. citriodorus ‘Aureus’, T. vulgaris ‘Faustini’).
The usefulness of visual rating of posterior atrophy in predicting rapid cognitive decline in Alzheimer disease: A preliminary study
Authors: Suh Jeewon , Park Young Ho , Kim Hang‐Rai , Jang Jae‐Won , Kang Min Ju , Yang Jimin , Baek Min Jae , Kim SangYun
Published: February 2019

Background

Approximately 10% to 30% of Alzheimer disease (AD) patients progress rapidly in severity and become more dependent on caregivers. Although several studies have investigated whether imaging biomarkers such as medial temporal atrophy (MTA) and posterior atrophy (PA) are useful for predicting the rapid progression of AD, their results have been inconsistent.

Objective

The study aims to investigate the association of visually rated MTA and PA with rapid disease progression in AD.

Methods

This was a retrospective cohort study of 159 AD patients who were initially diagnosed with mild AD and were followed for 1 year to determine whether they progressed rapidly (a decrease of three points or more on the Mini‐Mental State Examination over 1 year). We used 5‐point and 4‐point visual rating scales to assess MTA and PA, respectively. MTA and PA scores for each patient were dichotomized as normal (without atrophy) or abnormal (atrophy). We performed a logistic regression analysis to determine the odds ratios (ORs) of MTA and PA for rapid disease progression with adjustment for covariates.

Results

Within the study population, 47 (29.6%) patients progressed rapidly. Visual assessment of the magnetic resonance imaging (MRI) scans revealed that 112 patients (70.4%) showed MTA, whereas 80 patients (50.3%) showed PA. The ORs with 95% confidence intervals for MTA and PA were 1.825 (0.819‐4.070) and 2.844 (1.378‐5.835), respectively. The association of visually assessed PA, but not MTA, with rapid progression was significant after adjustment for covariates.

Conclusion

In patients with mild AD, visual assessment of PA exhibits independent predictive value for rapid disease progression.
Prevalence and determinants of subjective cognitive decline in a representative Greek elderly population
Authors: Vlachos George S. , Cosentino Stephanie , Kosmidis Mary H. , Anastasiou Costas A. , Yannakoulia Mary , Dardiotis Efthimios , Hadjigeorgiou Georgios , Sakka Paraskevi , Ntanasi Eva , Scarmeas Nikolaos
Published: February 2019

Objectives

We studied the prevalence of subjective cognitive decline (SCD) and its determinants in a sample of 1456 cognitively normal Greek adults ≥65 years old.

Methods/design

Subjects were evaluated by a multidisciplinary team on their neurological, medical, neuropsychological, and lifestyle profile to reach consensus diagnoses. We investigated various types of SCD, including single‐question, general memory decline, specific subjective memory decline based on a list of questions and three types of subjective naming, orientation, and calculation decline.

Results

In a single general question about memory decline, 28.0% responded positively. The percentage of our sample that reported at least one complaint related to subjective memory decline was 76.6%. Naming difficulties were also fairly common (26.0%), while specific deficits in orientation (5.4%) and calculations/currency handling (2.6%) were rare. The majority (84.2%) of the population reported subjective deficits in at least one cognitive domain. Genetic predisposition to dementia increased the odds for general memory decline by more than 1.7 times. For each one‐unit reduction in the neuropsychological composite score (a mean of memory, executive, language, visuospatial, and attention‐speed composite scores), the odds for decline in orientation increased by 40.3%. Depression/anxiety and increased cerebrovascular risk were risk factors for almost all SCD types.

Conclusions

SCD regarding memory is more frequent than non‐memory decline in the cognitively normal Greek elderly population. Genetic predisposition to dementia, lower cognitive performance, affective symptoms, and increased cerebrovascular risk are associated with prevalent SCD. Further prospective research is needed to improve understanding of the evolution of SCD over time.
Quality of education impacts late‐life cognition
Authors: Mantri Sneha , Nwadiogbu Chinwe , Fitts Whitney , Dahodwala Nabila
Published: February 2019

Objectives

Screening tests of global cognition detect racial differences in scores even after adjustment for educational attainment. Differential educational environments in adolescence may affect individual cognitive function. This study examines the impact of high school educational quality on late‐life cognition among community‐dwelling older adults.

Methods/design

Data were collected from community‐dwelling individuals from the Philadelphia Healthy Brain Aging (PHBA) cohort at the University of Pennsylvania Health System. The present analysis included subjects from the PHBA over the age of 55 years without a diagnosis of Parkinson's disease or dementia, who had attended high school in the City of Philadelphia. Cognition was assessed using the Montreal Cognitive Assessment (MoCA); clinical information was abstracted from the subject's electronic health record. High school information was obtained from the Philadelphia Board of Education. After univariable correlations were defined, we performed stepwise multiple linear regression models to determine the most significant predictors of late‐life cognitive status.

Results

A total of 130 subjects meeting inclusion criteria were included in the analysis. Years of education, race, educational level, school district, and financial status were all positively associated with MoCA. Significant negative associations included composite vascular risk, attendance at highly segregated schools, and historical poverty status. In stepwise multiple linear regression modeling, the impact of race on cognition remained significant when educational attainment was added to the model but was no longer significant once segregation status was added.

Conclusions

This work suggests that academic and community factors beyond years of education have a marked impact on late‐life cognition.