bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of membrane excitability in pancreatic β-cell glucotoxicity
Authors: Shyr Zeenat A. , Wang Zhiyu , York Nathaniel W. , Nichols Colin G. , Remedi Maria S.
Published: May 2019

Persistent hyperglycemia is causally associated with pancreatic β-cell dysfunction and loss of pancreatic insulin. Glucose normally enhances β-cell excitability through inhibition of KATP channels, opening of voltage-dependent calcium channels, increased [Ca2+]i, which triggers insulin secretion. Glucose-dependent excitability is lost in islets from KATP-knockout (KATP-KO) mice, in which β-cells are permanently hyperexcited, [Ca2+]i, is chronically elevated and insulin is constantly secreted. Mouse models of human neonatal diabetes in which KATP gain-of-function mutations are expressed in β-cells (KATP-GOF) also lose the link between glucose metabolism and excitation-induced insulin secretion, but in this case KATP-GOF β-cells are chronically underexcited, with permanently low [Ca2+]i and lack of glucose-dependent insulin secretion. We used KATP-GOF and KATP-KO islets to examine the role of altered-excitability in glucotoxicity. Wild-type islets showed rapid loss of insulin content when chronically incubated in high-glucose, an effect that was reversed by subsequently switching to low glucose media. In contrast, hyperexcitable KATP-KO islets lost insulin content in both low- and high-glucose, while underexcitable KATP-GOF islets maintained insulin content in both conditions. Loss of insulin content in chronic excitability was replicated by pharmacological inhibition of KATP by glibenclamide, The effects of hyperexcitable and underexcitable islets on glucotoxicity observed in in vivo animal models are directly opposite to the effects observed in vitro: we clearly demonstrate here that in vitro, hyperexcitability is detrimental to islets whereas underexcitability is protective.
Heat shock factor 1 protects germ cell proliferation during early ovarian differentiation in medaka
Authors: Furukawa Fumiya , Hamasaki Shin , Hara Seiji , Uchimura Tomoya , Shiraishi Eri , Osafune Natsumi , Takagi Hisanori , Yazawa Takashi , Kamei Yasuhiro , Kitano Takeshi
Published: May 2019

The heat shock response is important for the viability of all living organisms. It involves the induction of heat shock proteins whose expression is mainly regulated by heat shock factor 1 (HSF1). Medaka (Oryzias latipes) is a teleost fish with an XX/XY sex determination system. High water temperature (HT) inhibits the female-type proliferation of germ cells and induces the masculinisation of XX medaka in some cases during gonadal sex differentiation. Here, we investigated the roles of HSF1 on the proliferation of germ cells using HSF1 knockout medaka. Loss of HSF1 function under HT completely inhibited the female-type proliferation of germ cells, induced the expression of the anti-Mullerian hormone receptor type 2 (amhr2) and apoptosis-related genes, and suppressed that of the dead end (dnd) and heat shock protein-related genes. Moreover, the loss of HSF1 and AMHR2 function under HT recovered female-type proliferation in germ cells, while loss of HSF1 function under HT induced gonadal somatic cell apoptosis during early sex differentiation. These results strongly suggest that HSF1 under the HT protects the female-type proliferation of germ cells by inhibiting amhr2 expression in gonadal somatic cells. These findings provide new insights into the molecular mechanisms underlying environmental sex determination.
Effects of Pre-Anthesis Drought, Heat and Their Combination on the Growth, Yield and Physiology of diverse Wheat (Triticum aestivum L.) Genotypes Varying in Sensitivity to Heat and drought stress
Authors: Qaseem Mirza Faisal , Qureshi Rahmatullah , Shaheen Humaira
Published: May 2019

Independent and combined drought and heat stress negatively affect wheat yield and physiology. The present study was aimed to quantify effects of Drought [D], heat [H] and combined heat and drought [HD] during reproductive stage on wheat yield and to identify physio-biochemical traits which were strongly associated with improved yield and tolerance of wheat under stressful conditions. One hundred and eight elite diverse wheat genotypes were exposed to [H], [D] and [HD] treatments from heading till maturity. Grain yield was reduced by 56.47%, 53.05% and 44.66% under [HD], [H] and [D] treatment, respectively. The [HD] treatment affects the grain yield by reducing metabolism and mobilization of reserves to developing grains and leaves. Disintegration of membrane structure, chlorophyll and protein molecules was higher under [H] stress than [D] stress while water status of genotypes and sink strength was more affected by [D] than [H] stress. Multivariate analysis showed a strong correlation of chlorophyll content before and after anthesis, water-soluble carbohydrates (WSC), proline content (PC) and all other studies agronomic and physiological traits with grain yield while days to anthesis (DTA) and days to maturity (DTM) were negatively associated with grain yield under stress showing advantage of early maturity during stress. Traits having a major contribution in the first two principal components under different stress treatments may lead to improved varieties with heat and drought stress tolerance. To best of over knowledge, the present study is the first detailed study which used physiological and biochemical traits to explain the variation in grain yield and related traits in diverse wheat germplasm.
Acute-on-chronic liver disease enhances phenylephrine-induced endothelial nitric oxide release in rat mesenteric resistance arteries through enhanced PKA, PI3K/AKT and cGMP signalling pathways
Authors: Caracuel Laura , Sastre Esther , Llévenes Pablo , Prieto Isabel , Funes Tania , Aller Mª Ángeles , Arias Jaime , Balfagón Gloria , Blanco-Rivero Javier
Published: May 2019

Acute-on-chronic liver disease is a clinical syndrome characterized by decompensated liver fibrosis, portal hypertension and splanchnic hyperdynamic circulation. We aimed to determine whether the alpha-1 agonist phenylephrine (Phe) facilitates endothelial nitric oxide (NO) release by mesenteric resistance arteries (MRA) in rats subjected to an experimental microsurgical obstructive liver cholestasis model (LC). Sham-operated (SO) and LC rats were maintained for eight postoperative weeks. Phe-induced vasoconstriction (in the presence/absence of the NO synthase –NOS- inhibitor L-NAME) and vasodilator response to NO donor DEA-NO were analysed. Phe-induced NO release was determined in the presence/absence of either H89 (protein kinase –PK- A inhibitor) or LY 294002 (PI3K inhibitor). PKA and PKG activities, alpha-1 adrenoceptor, endothelial NOS (eNOS), PI3K, AKT and soluble guanylate cyclase (sGC) subunit expressions, as well as eNOS and AKT phosphorylation, were determined. The results show that LC blunted Phe-induced vasoconstriction, and enhanced DEA-NO-induced vasodilation. L-NAME increased the Phe-induced contraction largely in LC animals. The Phe-induced NO release was greater in MRA from LC animals. Both H89 and LY 294002 reduced NO release in LC. Alpha-1 adrenoceptor, eNOS, PI3K and AKT expressions were unchanged, but sGC subunit expression, eNOS and AKT phosphorylation and the activities of PKA and PKG were higher in MRA from LC animals. In summary, these mechanisms may help maintaining splanchnic vasodilation and hypotension observed in decompensated LC.
Formation of Surface Silver Nano-network Structures through Hot Electron Regulated Diffusion-limited Aggregation
Authors: Yao Yu-Feng , Yang Shaobo , Teng Chin-Chou , Chou Keng-Ping , Liu Chi-Wu , Kuo Yang , Kiang Yean-Woei , Yang Chih-Chung
Published: May 2019

A surface Ag nano-network pattern is formed by first depositing Ag nanoparticles (NPs) on a conductive template, which has a certain defect structure, and then illuminating the Ag NPs with ultraviolet (UV) light in a moist environment. Such an Ag nano-network pattern consists of multiple connected Brownian trees (BTs), which are produced through the diffusion-limited aggregation (DLA) process. In the DLA process, diffuse Ag+ ions, which are generated by UV light illumination and dissolved by a thin adsorbed water layer on the surfaces of the Ag NPs and used GaN template, settle to form a BT through the combination with excited hot electrons migrating into the template from the Ag NPs. The lateral transport of hot electrons in the template is regulated by the distributions of threading dislocation and point defect cluster in the template, which eventually become the centers of BTs. The structure of a surface Ag nano-network can potentially serve as a transparent conductor.
The effectiveness of hyposaline treatments against host-attached salmon lice
Authors: Sievers Michael , Oppedal Frode , Ditria Ellen , Wright Daniel W.
Published: May 2019

Understanding how salinity affects marine parasites is vital to understanding their ecology and treatment, particularly for host-parasite systems that traverse marine and freshwater realms such as the globally important Atlantic salmon (Salmo salar), salmon louse (Lepeophtheirus salmonis) system. Growing concerns for wild fish populations, and decreased efficiencies and burgeoning costs of lice treatments for farmed fish has necessitated more environmentally and socially acceptable delousing procedures, such as hyposaline treatments. The effect of brackish water on L. salmonis following primary attachment is largely unknown, with experimental evidence derived mostly from unattached or newly attached copepodids, or adult stages. We aimed to understand how attached lice respond to hyposaline environments to assess effectiveness as a parasite management strategy and to help better define delousing areas used by wild fish. Louse development at 4, 12, 19 and 26 ppt, and survival at 4 ppt, decreased as exposure times increased, but survival was otherwise unaffected. Subjecting salmon to fluctuating, repeat exposures did not influence efficacy. We confirm that free-swimming stages are susceptible, and show that attached copepodids were more tolerant than previously predicted based on experiments on alternate development stages. These results improve our understanding of the utility of hyposaline treatments in aquaculture and self-treating in wild fish, and could apply to other fish-lice parasite systems. Further, these data are important for models predicting host-parasite interactions and can contribute to predictive models on the transmission dynamics of sea lice from farm to wild fish.
Study on the icosahedral fullerene structure with ultra-light and pressure resistance character
Authors: Zhao Yifan , Lian Yin , Tan Huifeng
Published: May 2019

A large-scale helium-filled icosahedral fullerene structure is presented, which could be floatable in the air.
In vivo metal selectivity of metal-dependent biosynthesis of cobalt-type nitrile hydratase in Rhodococcus bacteria: a new look at the nitrile hydratase maturation mechanism?
Authors: Lavrov Konstantin V , Shemyakina Anna O , Grechishnikova Elena G , Novikov Andrey D , Kalinina Tatyana I , Yanenko Alexander S
Published: May 2019

This study highlights the effect of heavy metal ions on the expression of cobalt-containing nitrile hydratase (NHase) in Rhodococcus strains, which over-produce this enzyme. Both metal-dependent derepression of transcription and maturation of NHase were considered. We demonstrated that nickel ions can derepress the NHase promoter in several Rhodococcus strains. The cblA gene of a cobalt-dependent transcriptional repressor was shown to be indispensable for nickel-mediated derepression. As for maturation, we showed that nickel ions could not replace cobalt ions during the synthesis of active NHase. We also revealed that the amount of β-subunit decreased during NHase expression without added cobalt. We showed this using three variants of NHase in vivo synthesis: by using nickel- or urea-induced synthesis in cblA+ strains, and by using metal-independent constitutive synthesis in cblA− strains. In all cases, we found that the amount of β-subunit was significantly lower than the amount of α-subunit. In contrast, equimolar amounts of both subunits were synthesized after growth in the presence of added cobalt. Nickel did not affect NHase synthesis in mixtures with cobalt. This suggests that the metal selectivity in cblA-dependent regulation of NHase transcription was too low to discriminate between cobalt and nickel, but the selectivity of the NHase maturation mechanism was high enough to do so. Moreover, we can assume that the β-subunit is more subject to proteolytic degradation without the addition of cobalt, than the α-subunit. This indicates that cobalt ions presumably play an unknown role in the stability of the β-subunit in vivo.
Copper-catalyzed enantioselective Mukaiyama aldol reaction of silyl enol ethers with isatins
Authors: Li Jindong , Li Yanan , Sun Jianan , Gui Yang , Huang Yekai , Zha Zhenggen , Wang Zhiyong
Published: May 2019

A highly enantioselective Mukaiyama aldol reaction of silyl enol ethers with isatins was developed. A series of chiral 3-substituted 3-hydroxy-2-oxindoles could be obtained exclusively with high yields (up to 95%) and excellent enantioselectivities (up to 99%). In particular, water was essential to improve the diastereoselectivity.
Supramolecular calix[4]pyrrole polymers from a complementary pair of homoditopic host–guest molecules
Authors: Yuvayapan Samet , Aydogan Abdullah
Published: May 2019

Calix[4]pyrrole based thermoresponsive supramolecular polymers were demonstrated by using a complementary pair of homoditopic host and guest molecules.
Fluorine-substituted quinoidal thiophene with a F–H hydrogen bond locked conformation for high-performance n-channel organic transistors
Authors: Wang Deliang , Qiao Xiaolan , Ouyang Guangcheng , Wu Hongzhuo , Li Hongxiang
Published: May 2019

The novel dicyanomethylene-substituted 1,2-bis(thieno[3,2-b]thiophene-2-yl)ethene based quinoidal compounds QBTTE and F2-QBTTE are reported.
Cost-effective approach to detect Cu(ii) and Hg(ii) by integrating a smartphone with the colorimetric response from a NBD-benzimidazole based dyad
Authors: Anand Thangaraj , Sahoo Suban K.
Published: May 2019

A new optical chemosensor N1 was designed and synthesized by condensing 4-chloro-7-nitrobenzofurazan with 2-aminophenylbenzimidazole. In CH3OH : H2O (1 : 1, v/v) medium, sensor N1 exhibited high selectivity and sensitivity towards Cu2+ and Hg2+ ions by showing a distinct colour change from pale yellow to pink due to the internal charge transfer occurring between the sensor N1 and the Cu2+/Hg2+ ions upon complexation in 1 : 1 stoichiometry.
Coherent phase equilibria of systems with large lattice mismatch
Authors: Phan Anh Thu , Gheribi Aïmen E. , Chartrand Patrice
Published: May 2019

The elastic contribution to the Gibbs energy, representing the elastic energy stored in the coherent boundary, is formulated based on the linear elasticity theory in both the small and large deformation regimes. Several case studies have been examined in cubic systems, and the proposed formalism is showing an appropriate predictive capability.
Hydrogenation-controlled mechanical properties in graphene helicoids: exceptional distribution-dependent behavior
Authors: Sharifian Ali , Moshfegh Abouzar , Javadzadegan Ashkan , Hassanzadeh Afrouzi Hamid , Baghani Mostafa , Baniassadi Majid
Published: May 2019

Mechanical properties of pristine GHs along with patterned and randomly hydrogenated GHs have been investigated for various geometries and H-coverages.
Improved visible-light photoactivities of porous LaFeO3 by coupling with nanosized alkaline earth metal oxides and mechanism insight
Authors: Khan Iltaf , Sun Ning , Zhang Ziqing , Li Zhijun , Humayun Muhammad , Ali Sharafat , Qu Yang , Jing Liqiang
Published: May 2019

It is significant to improve visible-light photoactivities of porous LaFeO3 by coupling with nanosized alkaline earth metal oxides as dual-functional platform for accepting the high level electrons and activating CO2.
Confinement of Cu nanoparticles in the nanocages of large pore SBA-16 functionalized with carboxylic acid: enhanced activity and improved durability for 4-nitrophenol reduction
Authors: Deka Juti Rani , Lee Mu-Hsin , Saikia Diganta , Kao Hsien-Ming , Yang Yung-Chin
Published: May 2019

Fabrication of a highly active mesoporous silica SBA-16 supported Cu nanocatalyst with superb durability for the reduction of 4-nitrophenol into 4-aminophenol.
Luminescence color alteration induced by trapped solvent molecules in crystals of tetrahedral gold(i) complexes: near-unity luminescence mixed with thermally activated delayed fluorescence and phosphorescence
Authors: Osawa Masahisa , Yamayoshi Hiroto , Hoshino Mikio , Tanaka Yuya , Akita Munetaka
Published: May 2019

Emission color alteration caused by captured solvent molecules in the crystal lattice of tetrahedral gold(i) complexes.
Chelate rings of different sizes with non-innocent ligands
Authors: Kaim Wolfgang
Published: May 2019

Redox-active unsaturated chelate ligands can be realised with different ring sizes of the resulting metallacycles.
Self-grafting copper oxide nanoparticles show a strong enhancement of their anti-algal and anti-yeast action
Authors: Halbus Ahmed F. , Horozov Tommy S. , Paunov Vesselin N.
Published: May 2019

We report a strong amplification of the anti-algal and anti-yeast action of CuO nanoparticles surface-grafted with 4-hydroxyphenylboronic acid functional groups due to their covalent binding to carbohydrates on the cell membranes.
Highly efficient thermophones based on freestanding single-walled carbon nanotube films
Authors: Romanov Stepan A. , Aliev Ali E. , Fine Boris V. , Anisimov Anton S. , Nasibulin Albert G.
Published: May 2019

We present the state-of-the-art performance of air-coupled thermophones made of thin, freestanding films of randomly oriented single-walled carbon nanotubes (SWCNTs).
A single nanowire sensor for intracellular glucose detection
Authors: Liao Quan-Lan , Jiang Hong , Zhang Xin-Wei , Qiu Quan-Fa , Tang Yun , Yang Xiao-Ke , Liu Yan-Ling , Huang Wei-Hua
Published: May 2019

We report for the first time the development of a single nanowire electrochemical sensor for the detection of intracellular glucose levels.
Synthesis of far-red- and near-infrared-emitting Cu-doped InP/ZnS (core/shell) quantum dots with controlled doping steps and their surface functionalization for bioconjugation
Authors: Lim Mihye , Lee Wonseok , Bang Gyuhyun , Lee Woo Jin , Park Youngrong , Kwon Yongju , Jung Yebin , Kim Sungjee , Bang Jiwon
Published: May 2019

Non-cadmium-based highly bright and stable far-red- and near-infrared (NIR)-emitting Cu-doped InP/ZnS (core/shell) quantum dots were synthesized with precisely controlled doping steps and were employed for bioimaging probes.
Phosphine-catalyzed dearomative (3 + 2) annulation of 2-nitrobenzofurans and nitrobenzothiophenes with allenoates
Authors: Zhao Jian-Qiang , Yang Lei , You Yong , Wang Zhen-Hua , Xie Ke-Xin , Zhang Xiao-Mei , Xu Xiao-Ying , Yuan Wei-Cheng
Published: May 2019

An efficient Ph2PMe-catalyzed dearomative (3 + 2) annulation of 2-nitrobenzofurans, 2-nitrobenzothiophenes, and 3-nitrobenzothiophenes with allenoates is reported.
Bianthryl-based organocatalysts for the asymmetric Henry reaction of fluoroketones
Authors: Otevrel Jan , Svestka David , Bobal Pavel
Published: May 2019

An efficient organocatalyzed asymmetric Henry reaction between α-fluoroketones and nitroalkanes has been developed.
Radical polymerization of ‘dehydroaspirin’ with the formation of a hemiacetal ester skeleton: a hint for recyclable vinyl polymers
Authors: Kazama Akane , Kohsaka Yasuhiro
Published: May 2019

A recyclable vinyl polymer was developed via radical polymerization of ‘dehydroaspirin’ derived from acetylsalicylic acid.
Mechanochemistry allows carrying out sensitive organometallic reactions in air: glove-box-and-Schlenk-line-free synthesis of oxidative addition complexes from aryl halides and palladium(0)
Authors: Kubota Koji , Takahashi Rina , Ito Hajime
Published: May 2019

We have demonstrated that mechanochemistry allows synthesizing a wide range of palladium oxidative addition complexes in air.
Photoelectric effect accelerated electrochemical corrosion and nanoimprint processes on gallium arsenide wafers
Authors: Guo Chengxin , Zhang Lin , Sartin Matthew M. , Han Lianhuan , Tian Zhao-Wu , Tian Zhong-Qun , Zhan Dongping
Published: May 2019

Here we report photoelectric-effect-enhanced interfacial charge transfer reactions.
Cooperative photocatalytic selective aerobic oxidation of alcohols on anatase TiO2
Authors: Wang Ningning , Shi Ji-Long , Hao Huimin , Yuan Hong , Lang Xianjun
Published: May 2019

5(6)-Carboxyfluorescein-sensitized anatase TiO2 photocatalyst with 4-methoxy-2,2,6,6-tetramethylpiperidine1-oxyl as a cocatalyst were selected to undertake the cooperative photocatalytic selective aerobic oxidation of alcohols.
Colonic electrical stimulation promotes colonic motility through regeneration of myenteric plexus neurons in slow transit constipation beagles
Authors: Wang Yongbin , Wang Qian , Kuerban Kudelaidi , Dong Mengxue , Qi Feilong , Li Gang , Ling Jie , Qiu Wei , Zhang Wenzhong , Ye Li
Published: May 2019

Slow transit constipation (STC) is a common disease characterized by markedly delayed colonic transit time as a result of colonic motility dysfunction. It is well established that STC is mostly caused by disorders of relevant nerves, especially the enteric nervous system (ENS). Colonic electrical stimulation (CES) has been regarded as a valuable alternative for the treatment of STC. However, little report focuses on the underlying nervous mechanism to normalize the delayed colonic emptying and relieve symptoms. In the present study, the therapeutic effect and the influence on ENS triggered by CES were investigated in STC beagles. The STC beagle model was established by oral administration of diphenoxylate/atropine and alosetron. Histopathology, electron microscopy, immunohistochemistry, Western blot analysis and immunofluorescence were used to evaluate the influence of pulse train CES on myenteric plexus neurons. After 5 weeks of treatment, CES could enhance the colonic electromyogram (EMG) signal to promote colonic motility, thereby improving the colonic content emptying of STC beagles. HE staining and transmission electron microscopy confirmed that CES could regenerate ganglia and synaptic vesicles in the myenteric plexus. Immunohistochemical staining showed that synaptophysin (SYP), protein gene product 9.5 (PGP9.5), cathepsin D (CAD) and S-100B in the colonic intramuscular layer were up-regulated by CES. Western blot analysis and immunofluorescence further proved that CES induced the protein expression of SYP and PGP9.5. Taken together, pulse train CES could induce the regeneration of myenteric plexus neurons, thereby promoting the colonic motility in STC beagles.
Oxidative and endoplasmic reticulum stresses are involved in palmitic acid-induced H9c2 cell apoptosis
Authors: Yang Lei , Guan Gaopeng , Lei Lanjie , Liu Jianyun , Cao Lingling , Wang Xiangguo
Published: May 2019

Palmitic acid (PA) is the most common saturated long-chain fatty acid that causes damage to heart muscle cells. However, the molecular mechanism of PA toxicity in myocardial cells is not fully understood. In the present study, we explored the effects of PA on proliferation and apoptosis of H9c2 cardiomyocytes, and uncovered the signaling pathways involved in PA toxicity. Our study revealed induction of both oxidative and endoplasmic reticulum (ER) stresses and exacerbation of apoptosis in PA-treated H9c2 cells. Inhibition of oxidative stress by N-acetylcysteine (NAC) reduced apoptosis and decreased ER stress in PA-treated H9c2 cells. Moreover, inhibition of ER stress by 4-phenyl butyric acid decreased apoptosis and attenuated oxidative stress. In summary, the present study demonstrated that oxidative stress coordinates with ER stress to play important roles in PA-induced H9c2 cell apoptosis.
Proximate molecular quasar absorbers
Authors: Noterdaeme P. , Balashev S. , Krogager J.-K. , Srianand R. , Fathivavsari H. , Petitjean P. , Ledoux C.
Published: May 2019

We present results from a search for strong H2 absorption systems proximate to quasars (zabs ≈ zem) in the Sloan Digital Sky Survey (SDSS) Data Release 14. The search is based on the Lyman-Werner band signature of damped H2 absorption lines without any prior on the associated metal or neutral hydrogen content. This has resulted in the detection of 81 systems with N(H2) ∼ 1019 − 1020 cm−2 located within a few thousand km s−1 from the quasar. Compared to a control sample of intervening systems, this implies an excess of proximate H2 systems by about a factor of 4 to 5. The incidence of H2 systems increases steeply with decreasing relative velocity, reaching an order of magnitude higher than expected from intervening statistics at Δv <  1000 km s−1. The most striking feature of the proximate systems compared to the intervening ones is the presence of Ly − α emission in the core of the associated damped H I absorption line in about half of the sample. This puts constraints on the relative projected sizes of the absorbing clouds to those of the quasar line emitting regions. Using the SDSS spectra, we estimate the H I, metal and dust content of the systems, which are found to have typical metallicities of one tenth Solar, albeit with a large spread among individual systems. We observe trends between the fraction of leaking Ly − α emission and the relative absorber-quasar velocity as well as with the excitation of several metal species, similar to what has been seen in metal-selected proximate DLAs. With the help of theoretical H I-H2 transition relations, we show that the presence of H2 helps to break the degeneracy between density and strength of the UV field as main sources of excitation and hence provides unique constraints on the possible origin and location of the absorbing clouds. We suggest that most of these systems originate from galaxies in the quasar group, although a small fraction of them could be located in the quasar host as well. We conclude that follow-up observations are still required to investigate the chemical and physical conditions in individual clouds and to assess the importance of AGN feedback for the formation and survival of H2 clouds.
Standing in the shadow of dark gas: ALMA observations of absorption from dark CO in the molecular dark neutral medium of Chamaeleon
Authors: Liszt H. , Gerin M. , Grenier I.
Published: May 2019

Context. We previously detected 89.2 GHz J = 1−0 HCO+ absorption in 12 directions lacking detected CO emission in the outskirts of the Chamaeleon cloud complex and toward one sightline with integrated CO emission WCO = 2.4 K km s−1. Eight sightlines had a much larger mean column density of dark neutral medium (DNM) – gas not represented in HI or CO emission – and were found to have much higher mean molecular column density. The five other sightlines had little or no DNM and were found to have much smaller but still detectable N(HCO+).

Aims. To determine the CO column density along previously observed Chamaeleon sightlines and to determine why CO emission was not detected in directions where molecular gas is present.

Methods. We took 12CO J = 1−0 absorption profiles toward five sightlines having higher DNM and HCO+ column densities and one sightline with smaller N(DNM) and N(HCO+). We converted the integrated HCO+ optical depths to N(H2) in the weak-excitation limit using N(HCO+)/N(H2) = 3 × 10−9 and converted the integrated CO optical depths ϒCO to CO column density using the relationship N(CO) = 1.861 × 1015 cm−2 ϒCO1.131 found along comparable lines of sight that were previously studied in J = 1−0 and J = 2−1 CO absorption and emission.

Results. CO absorption was detected along the five sightlines in the higher-DNM group, with CO column densities 4 × 1013 cm−2≲ N(CO) ≲1015 cm−2 that are generally below the detectability limit of CO emission surveys.

Conclusions. In the outskirts of the Chamaeleon complex, the presence of molecular DNM resulted primarily from small CO column densities at the onset of CO formation around the HI/H2 transition in diffuse molecular gas. CO relative abundances N(CO)/H2 ≲2 × 10−6 in the outskirts of Chamaeleon are comparable to those seen in UV absorption toward early-type stars, including in Chamaeleon.
petitRADTRANS
Authors: Mollière P. , Wardenier J. P. , van Boekel R. , Henning Th. , Molaverdikhani K. , Snellen I. A. G.
Published: May 2019

We present the easy-to-use, publicly available, Python package petitRADTRANS, built for the spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission and emission spectra within a few seconds at low resolution (λ/Δλ = 1000; correlated-k method) and high resolution (λ/Δλ = 106; line-by-line method), using only a few lines of input instruction. The somewhat slower, correlated-k method is used at low resolution because it is more accurate than methods such as opacity sampling. Clouds can be included and treated using wavelength-dependent power law opacities, or by using optical constants of real condensates, specifying either the cloud particle size, or the atmospheric mixing and particle settling strength. Opacities of amorphous or crystalline, spherical or irregularly-shaped cloud particles are available. The line opacity database spans temperatures between 80 and 3000 K, allowing to model fluxes of objects such as terrestrial planets, super-Earths, Neptunes, or hot Jupiters, if their atmospheres are hydrogen-dominated. Higher temperature points and species will be added in the future, allowing to also model the class of ultra hot-Jupiters, with equilibrium temperatures Teq ≳ 2000 K. Radiative transfer results were tested by cross-verifying the low- and high-resolution implementation of petitRADTRANS, and benchmarked with the petitCODE, which itself is also benchmarked to the ATMO and Exo-REM codes. We successfully carried out test retrievals of synthetic JWST emission and transmission spectra (for the hot Jupiter TrES-4b, which has a Teq of ∼1800 K).
Precession of the non-rigid Earth: Effect of the mass redistribution
Authors: Baenas T. , Escapa A. , Ferrándiz J. M.
Published: May 2019

This research is focused on determining the contribution to the precession of the Earth’s equator due to the mass redistribution stemming from the gravitational action of the Moon and the Sun on a rotating solid Earth. In the IAU2006 precession theory, this effect is taken into account through a contribution of −0.960 mas cy−1for the precession in longitude (with the unspecific name of non-linear effect). In this work, the revised value of that second-order contribution reaches −37.847 mas cy−1when using the Love numbers values given in IERS Conventions, and −43.945 mas cy−1if those values are supplemented with the contributions of the oceanic tides. Such variations impose a change of the first-order precession value that induces relative changes of the Earth’s dynamical ellipticity of about 7.3 and 8.5 ppm, respectively. The corresponding values for the obliquity rate are 0.0751 and 0.9341 mas cy−1, respectively, in contrast to 0.340 mas cy−1considered in IAU2006. The fundamentals of the modeling have been revisited by giving a clear construction of the redistribution potential of the Earth through the corresponding changes in the Earth tensor of inertia. The dynamical problem is tackled within the Hamiltonian framework of a two-layer Earth model, introduced and developed by Getino and Ferrándiz. This approach allows for the achievement of closed-analytical formulae for the precession in longitude and obliquity. It makes it possible to obtain numerical values for different Earth models once a set of associated Love numbers is selected. The research is completed with a discussion on the permanent tide and the related estimation of the variation of the second degree zonal Stokes parameter,J2, and also the indirect effects on nutations arising from the relative change of the Earth’s dynamical ellipticity.
Cluster induced quenching of galaxies in the massive cluster XMMXCS J2215.9−1738 at z ∼ 1.5 traced by enhanced metallicities inside half R200
Authors: Maier C. , Hayashi M. , Ziegler B. L. , Kodama T.
Published: May 2019

Aims. Cluster environments at z <  0.5 were found to increase the gas metallicities of galaxies which enter inner regions of the clusters where the density of the intracluster medium is high enough to remove their hot halo gas by ram-pressure stripping effects and to stop the inflow of pristine gas. To extend these studies to z >  1, the most massive clusters known at these redshifts are the sites where these environmental effects should be more pronounced and more easily observed with present day telescopes.

Methods. We explore the massive cluster XMMXCS J2215.9−1738 at z ∼ 1.5 with KMOS spectroscopy of Hα and [N II] λ 6584 covering a region that corresponds to about one virial radius. Using published spectroscopic redshifts of 108 galaxies in and around the cluster we computed the location of galaxies in the projected velocity-versus-position phase-space to separate our cluster sample into a virialized region of objects accreted longer ago (roughly inside half R200) and a region of infalling galaxies. We measured oxygen abundances for ten cluster galaxies with detected [N II] λ 6584 lines in the individual galaxy spectra and compared the mass–metallicity relation of the galaxies inside half R200 with the infalling galaxies and a field sample at similar redshifts.

Results. We find that the oxygen abundances of individual z ∼ 1.5 star-forming cluster galaxies inside half R200 are comparable, at the respective stellar mass, to the higher local SDSS metallicity values. We compare our measurements with a field galaxy sample from the KMOS3D survey at similar redshifts. We find that the [N II] λ 6584/Hα line ratios inside half R200 are higher by 0.2 dex and that the resultant metallicities of the galaxies in the inner part of the cluster are higher by about 0.1 dex, at a given mass, than the metallicities of infalling galaxies and of field galaxies at z ∼ 1.5. The enhanced metallicities of cluster galaxies at z ∼ 1.5 inside 0.5R200 indicate that the density of the intracluster medium in this massive cluster becomes high enough toward the cluster center such that the ram pressure exceeds the restoring pressure of the hot gas reservoir of cluster galaxies. This can remove the gas reservoir and initiate quenching; although the galaxies continue to form stars, albeit at slightly lower rates, using the available cold gas in the disk which is not stripped.
Solid-liquid exchange between uranium and a synthetic apatite: towards uranium decorporation from bone matrix
Authors: Wang Jingxian , Bourgeois Damien , Meyer Daniel
Published: May 2019

Natural uranium exhibits chemical toxicity, especially known with its acute effects on kidney. Simultaneously, it has been proved that uranium accumulates in bones during long-term exposure[1] but its chronical effects on bones are not clear. Particularly the mechanisms associated to accumulation into and release from bones are unknown, which is key to design and test decorporation reagents in future. Bone is a complicated organ, composed of mineralized apatite and organic compounds (mostly type I collagen). Our work is dedicated to the understanding of how uranium is accumulated in the inorganic bone matrix through chemical pathways, and what factors influence the solid/liquid equilibrium between uranium and the bone. To fulfil this goal, apatite materials which mimic bone apatite have been synthesized, with and without uranium. Such apatite materials have been pre-equilibrated with a fluid mimicking blood plasma at physiological pH=7.4.
Blue light hazard: does rat retina make relevant model for discussing exposure limit values applicable to humans?
Authors: Point S. , Beroud M.
Published: May 2019

Recent scientific papers have drawn attention to potential blue light hazard associated with the use of LED lighting and the validity of exposure limit values of safety norms has been called into question. But can data coming from rat model experiments be extrapolated to human? This article provides some basic recommendations regarding rat retinal irradiance calculations and its potential extrapolation to human.
Palladium-Catalyzed C12-Selective Direct Arylation of [1,2-c]Quinazolin-6(5H)-ones
Authors: Arcadi Antonio , Cacchi Sandro , Fabrizi Giancarlo , Fochetti Andrea , Ghirga Francesca , Goggiamani Antonella , Iazzetti Antonia , Marinelli Fabio
Published: May 2019

A straightforward approach to the synthesis of the challenging 12-arylindolo[1,2-c]quinazolin-6(5H)-ones through the palladium-catalyzed direct arylation of N-benzyl and NH-free [1,2-c]quinazolin-6(5H)-ones with aryl halides is described.
Enantioselective Synthesis of 2-Substituted Pyrrolidines via Intramolecular­ Reductive Amination
Authors: Zhou Huan , Zhao Wenlei , Zhang Tao , Guo Haodong , Huang Haizhou , Chang Mingxin
Published: May 2019

Catalyzed by the complex generated in situ from iridium and the chiral ferrocene ligand, tert-butyl (4-oxo-4-arylbutyl)carbamate substrates were deprotected and then reductively cyclised to form 2-substituted arylpyrrolidines in a one-pot manner, in which the intramolecular reductive amination was the key step. A range of chiral 2-substituted arylpyrrolidines were synthesised in up to 98% yield and 92% ee.
Recent Advances in Electrochemistry for the Synthesis of N-Heterocycles
Authors: Sbei Najoua , Listratova Anna V. , Titov Alexander A. , Voskressensky Leonid G.
Published: May 2019

The construction of N-heterocyclic rings represents a very important and fast-developing area of organic synthesis. In this context, electrochemistry has emerged as a mild solution for generating in situ the required electrophilic substrates, bases and nucleophiles derived from low-level and extremely stable reagents, the further application of which makes some heterocycles more accessible. In this review, we have covered the recent advances in the electrochemical synthesis of five- and six-membered N-heterocyclic compounds published from 2017 to October 2018.

1 Introduction

2 Electrochemical Synthesis of Five-Membered N-Containing Heterocycles

2.1 Pyrrolidines

2.2 Imidazoles

2.3 Pyrazoles

2.4 Triazoles

2.5 Oxazoles

2.6 Indoles

2.7 Thiazoless

3 Electrochemical Synthesis of Six-Membered N-Containing Heterocycles

3.1 Piperidines and Pyridines

3.2 Quinazolinones

3.3 Benzoxazines

4 Conclusions
Self-diffusion of water–cyclohexane mixtures in supercritical conditions as studied by NMR and molecular dynamics simulation
Authors: Yoshida Ken , Nakahara Masaru
Published: May 2019

The self-diffusion coefficients of water (Dw) and cyclohexane (Dch) in their binary mixtures were determined using the proton pulsed field gradient spin-echo method from medium to low densities in subcritical and supercritical conditions. The density (ρ), temperature (T), and water mole fraction (xw) are studied in the ranges 0.62–6.35 M (M = mol dm−3), 250–400 °C, and 0.109–0.994, respectively. A polynomial fitting function was developed for a scaled value of Ξ = ρDT−1/2 with ρ, T, and xw as variables in combination with a comprehensive molecular dynamics (MD) simulation. The NMR and MD results agree within 5% for water and 6% for cyclohexane, on average. The differences between Dw and Dch in the dependence on ρ, T, and xw are characterized by the activation energy Ea and the activation volume ΔVΞ‡ expressed by the scaled fitting function. The decrease in the ratio Dw/Dch and the increase in the Ea of water with increasing xw are related to the increase in the number of hydrogen bonds (HBs). The Dw value for a solitary water molecule at a low xw is controlled by the solvation shell, most of which is occupied by nonpolar cyclohexane molecules that provide less friction as a result of weaker interactions with water. A microscopic diffusion mechanism is discussed based on an analysis of the HB number as well as the first-peak height of the radial distribution functions that are taken as measures of the potential of the mean field controlling self-diffusion.
A dynamic-difference approach to scan probe microwave reflectivity mapping of the nanoscale electronic properties of single-walled carbon nanotubes
Authors: Seabron Eric , MacLaren Scott , Jones Keith , Wilson William L.
Published: May 2019

Understanding carbon nanotubes (CNTs) based electronic devices requires strategies to characterize individual nanotube electronic properties. We will explore a new nonevasive approach to microwave impedance microscopy (MIM) which, we hypothesize, utilizes the ambient water layer as a nanoscale high permittivity medium. This approach eliminates the need for a thin metal oxide surface layer, used in contact mode MIM-AFM of CNTs, which completely obscures resistance mapping and can increase surface roughness by >10×. The potential novelty of our proposed MIM methodology is that the water meniscus, known to form beneath the tip, creates a localized high permittivity environment between the tip and the surface. The materials microwave response image is extracted from the “capacitive difference” observed on trajectories’ measures via the transmission line cantilever during approach. We can mechanically detect the water meniscus formation using AFM force curves while simultaneously mapping resistance, capacitance, and topography. When comparing signal-to-noise (SNR), to contact MIM-AFM, our results suggest a >2× increase in MIM capacitance SNR, 10–100× improvement in MIM resistance SNR, and up to 3× increase in the capacitance mapping resolution by reducing the effects of tip–surface spatial convolution.
Reactive power optimization of an active distribution network including a solid state transformer using a moth swarm algorithm
Authors: Shi Jiying , Yang Wenjing , Xue Fei , Qiao Wen , Zhang Di
Published: May 2019

This paper presents a reactive power optimization model for an active distribution network (ADN), including a solid state transformer (SST). In this model, the SST, as a power electronic device, compensates the system reactive power by adjusting the modulation coefficients and phase angles of the voltage source converter. A sequential multiscenario technique is implemented to simulate the transient characteristics of distributed generators (DGs). By optimizing the continuous variables of the SST and the reactive power output of a controllable DG, voltage deviation and power loss of the ADN are minimized. Meanwhile, although the cost of an SST is higher than that of a traditional transformer, using this model reduces the total cost of the system through reactive power optimization. In addition, a moth swarm algorithm is proposed. By adopting a position updating strategy of Lévy mutation, lateral positioning, and celestial navigation, the convergence speed and global optimization capability of the algorithm are improved. Finally, the rationality and validity of the proposed model and algorithm are verified by simulation of the IEEE 33-bus system.
Describing nonequilibrium soft matter with mean field game theory
Authors: Welch P. M. , Rasmussen K. Ø. , Welch C. F.
Published: May 2019

We demonstrate that combining an emerging approach to game theory with self-consistent mean field theory provides realistic treatments of diblock copolymer phase evolution. We especially examine order-order phase transformations upon quenched temperature change involving hexagonal cylinders, lamellae, and the gyroid. Our findings demonstrate that (i) the game theoretical dynamics produce realistic trajectories for the evolution of the local compositions, (ii) the predicted small-angle scattering follows experimentally observed trends, (iii) nucleation and growth is active when the system is quenched far from the critical point, and (iv) epitaxial growth is manifest. To our knowledge, the methodology presented provides the first merger of mean field game theory and statistical mechanics for soft matter systems, giving a new inroad to studying polymer dynamics.
Shape oscillation of a sessile drop under the effect of high frequency amplitude-modulated magnetic field
Authors: Zhu Hong-da , Lei Zuo-sheng , Zhang Li-jie , Guo Jia-hong
Published: May 2019

The shape oscillation behavior of a sessile mercury drop under the effect of high frequency amplitude-modulated magnetic field (AMMF) is investigated experimentally. It is an effective method to excite the shape oscillation of a liquid metal sessile drop. The high frequency AMMF is generated by a solenoid inductor fed by a specially designed alternating electric current. The surface contour of the sessile drop is observed by a digital camera. At a given modulation frequency and magnetic flux density of the high frequency AMMF, the edge deformations of the drop with azimuthal wave numbers (modes n = 2, 3, 4, 5, 6) were excited. A stability diagram of the shape oscillation of the drop is obtained by analysis of the experimental data. It turns out that when the modulation frequency and magnetic flux density reach a point in the stability diagram which can trigger shape oscillations of the drop of several modes, the shape oscillation of different modes may be seen alternatively.
The effect of ice type on ice adhesion
Authors: Rønneberg Sigrid , Laforte Caroline , Volat Christophe , He Jianying , Zhang Zhiliang
Published: May 2019

To lower the ice adhesion strength is the most efficient technique for passive ice removal for several applications. In this paper, the effect of different types of ice on the ice adhesion strength was investigated. The ice types precipitation ice, in-cloud ice and bulk water ice on the same aluminum substrate and under similar environmental conditions were investigated. The ice adhesion strength was measured with a centrifugal adhesion test and varied from 0.78 ± 0.10 MPa for precipitation ice, 0.53 ± 0.12 MPa for in-cloud ice to 0.28 ± 0.08 MPa for bulk water ice. The results indicate that the ice adhesion strength inversely correlates with the density of ice. The results inspire a new strategy in icephobic surface development, specifically tailored to the relevant ice type.
Excited state dynamics of CH2I2 and CH2BrI studied with UV pump VUV probe photoelectron spectroscopy
Authors: Horton Spencer L. , Liu Yusong , Forbes Ruaridh , Makhija Varun , Lausten Rune , Stolow Albert , Hockett Paul , Marquetand Philipp , Rozgonyi Tamás , Weinacht Thomas
Published: May 2019

We compare the excited state dynamics of diiodomethane (CH2I2) and bromoiodomethane (CH2BrI) using time resolved photoelectron spectroscopy. A 4.65 eV UV pump pulse launches a dissociative wave packet on excited states of both molecules and the ensuing dynamics are probed via photoionization using a 7.75 eV probe pulse. The resulting photoelectrons are measured with the velocity map imaging technique for each pump-probe delay. Our measurements highlight differences in the dynamics for the two molecules, which are interpreted with high-level ab initio molecular dynamics (trajectory surface hopping) calculations. Our analysis allows us to associate features in the photoelectron spectrum with different portions of the excited state wave packet represented by different trajectories. The excited state dynamics in bromoiodomethane are simple and can be described in terms of direct dissociation along the C–I coordinate, whereas the dynamics in diiodomethane involve internal conversion and motion along multiple dimensions.