bluuebunny/crossref_metadata_2025 huggingface dataset:
Volume-invariant ionic liquid microbands as highly durable wearable biomedical sensors
Authors: Wang Yan , Gong Shu , Wang Stephen Jia , Simon George P. , Cheng Wenlong
Published: January 2016

Non-volatile and flow properties of ionic liquids allow for simple ‘fill and seal’ approach to fabricate high-performance wearable sensors without materials delamination or cracking.
A novel arsenic methyltransferase gene of Westerdykella aurantiaca isolated from arsenic contaminated soil: phylogenetic, physiological, and biochemical studies and its role in arsenic bioremediation
Authors: Verma Shikha , Verma Pankaj Kumar , Meher Alok Kumar , Dwivedi Sanjay , Bansiwal Amit Kumar , Pande Veena , Srivastava Pankaj Kumar , Verma Praveen Chandra , Tripathi Rudra Deo , Chakrabarty Debasis
Published: January 2016

The study explores new insights into the arsenic metabolism by WaarsM and provides a potential approach for the bioremediation process.
Synthesis and characterization of metal-substituted tetraalkylphosphonium polyoxometalate ionic liquids
Authors: Santos Filipe M. , Magina Sandra P. , Nogueira Helena I. S. , Cavaleiro Ana M. V.
Published: January 2016

Trihexyl(tetradecyl)phosphonium and Keggin polyoxotungstates [PW11O39M(H2O)]n−, M = Fe, Co, Mn, or related lacunary [PW11O39]7−and [P2W20O70(H2O)2]10−anions yield compounds that are liquids at room temperature.
Biosynthesis, characterization and catalytic activity of an Ag/zeolite nanocomposite for base- and ligand-free oxidative hydroxylation of phenylboronic acid and reduction of a variety of dyes at room temperature
Authors: Hatamifard Arezo , Nasrollahzadeh Mahmoud , Sajadi S. Mohammad
Published: January 2016

A green synthesis of an Ag/zeolite nanocomposite and its catalytic activity were investigated. Its catalytic efficiency remains unaltered even after several repeated cycles.
Ionic liquids: the view from Mount Improbable
Authors: Deetlefs Maggel , Fanselow Markus , Seddon Kenneth R.
Published: January 2016

The ionic liquid literature has grown at a remarkable rate since 1998, making it increasingly difficult to assess the important research directions and the underlying, fundamental understanding of ionic liquids.
Castor leaf mediated synthesis of iron nanoparticles for evaluating catalytic effects in transesterification of castor oil
Authors: Rengasamy Mookan , Anbalagan Krishnasamy , Kodhaiyolii Shanmugam , Pugalenthi Velan
Published: January 2016

A castor (Ricinus communis) leaf extract mediated process was developed for the synthesis of iron nanoparticles. The phytosynthesized iron nanoparticles were used as a catalyst for castor biodiesel production.
Grain size dependent magnetoelectric coupling of BaTiO3 nanoparticles
Authors: Woldu Tesfakiros , Raneesh B. , Reddy M. V. Ramana , Kalarikkal Nandakumar
Published: January 2016

We report the magnetoelectric (ME) coupling properties of BaTiO3 nanoparticles of different grain sizes ranging from 16–26 nm synthesized using a modified Pechini method.
Down shifting and quantum cutting from Eu3+, Yb3+ co-doped Ca12Al14O33 phosphor: a dual mode emitting material
Authors: Yadav R. V. , Yadav R. S. , Bahadur A. , Rai S. B.
Published: January 2016

We report the quantum cutting (QC) in a Eu3+, Yb3+ co-doped Ca12Al14O33 phosphor synthesized through combustion method.
CdSe QDs@UIO-66 composite with enhanced photocatalytic activity towards RhB degradation under visible-light irradiation
Authors: Gan Haijun , Wang Zhen , Li Huimin , Wang Yuanrui , Sun Linping , Li Yafeng
Published: January 2016

Preparation of core–shell CdSe QDs@UIO-66 by the method of ship-in-bottle and enhanced photocatalysis to RhB under visible-light irradiation.
Carbon dioxide capture by amino-functionalized ionic liquids: DFT based theoretical analysis substantiated by FT-IR investigation
Authors: Cao Bobo , Du Jiuyao , Liu Shuangyue , Zhu Xiao , Sun Xuejun , Sun Haitao , Fu Hui
Published: January 2016

Both computational and experimental studies show amino-functionalized ionic liquids, [aEMMIM][X] (X = F, Cl, Br, and I), can chemically capture CO2.
In situ transmission electron microscopy study of the electrochemical sodiation process for a single CuO nanowire electrode
Authors: Zhang Liqiang , Wang Yuecun , Xie Degang , Tang Yushu , Wu Chunyang , Cui Lishan , Li Yongfeng , Ning Xiaohui , Shan Zhiwei
Published: January 2016

The electrochemically driven sodiation and desodiation process in a CuO nanowire was characterized by using in situ TEM. This work contributes to understanding of the electrochemical conversion mechanism of CuO nanowire anodes applied in NIBs.
Soft-matter led hardening of concrete: enhancement of compressive and thermal strength of concrete by polymers and nanoparticles
Authors: Biswas Subharanjan , Vinnakota Sumanjani , Roy Soumyajit
Published: January 2016

Supramolecularly bound polyacrylic acid & urea based scaffolds & nanoparticles in form of defects improve strength and thermal resistivity of concrete.
Electronic structure and spectral properties of aurones as visible range fluorescent probes: a DFT/TDDFT study
Authors: Xue Yunsheng , Dou Yunyan , An Lin , Zheng Youguang , Zhang Ling , Liu Yi
Published: January 2016

A DFT and TDDFT study was performed to understand the electronic and optical properties of aurone and its amine-substituted derivatives as potential fluorescent probes.
Interactions governing the entrapment of anticancer drugs by low-molecular-weight hydrogelator for drug delivery applications
Authors: Gupta Siddhi , Singh Manish , M. Amarendar Reddy , Yavvari Prabhu S. , Srivastava Aasheesh , Bajaj Avinash
Published: January 2016

We present the effect of size, charge, and hydrophobicity of anticancer drugs on their drug encapsulation efficacy in anl-alanine-based small-molecule hydrogelator.
Non-pitch coal-based activated coke introduced CeOx and/or MnOx for low temperature selective catalytic reduction of NOx by NH3
Authors: Fu Yali , Zhang Yongfa , Li Guoqiang , Zhang Jing , Tian Fang
Published: January 2016

On the modified activated coke, the CeOx species, promoting NOx adsorption, significantly increased the starting denitrification activity and the Mn species, helping NH3 adsorption, showed a gradual increase in activity after a time delay.
2,2′-Bis(trifluoromethyl)biphenyl as a building block for highly ambient-stable, amorphous organic field-effect transistors with balanced ambipolarity
Authors: Chaing Chi-Jui , Chen Jyh-Chien , Kuo Yu-Ju , Tsao Hsiang-Yen , Wu Kuan-Yi , Wang Chien-Lung
Published: January 2016

Ambipolar and annealing-free OFETs with high ambient-stability are achieved by introducing 2,2′-bis(trifluoromethyl)biphenyl as the acceptor.
A seawater triggered dynamic coordinate bond and its application for underwater self-healing and reclaiming of lipophilic polymer
Authors: Xia Nan Nan , Xiong Xiao Min , Wang Junhu , Rong Min Zhi , Zhang Ming Qiu
Published: January 2016

Bulk polymer capable of repeatedly underwater self-healing and reclaiming is synthesized under the inspiration of the formation of a mussel byssus cuticle.
Hyperbranched polysiloxane (HBPSi)-based polyimide films with ultralow dielectric permittivity, desirable mechanical and thermal properties
Authors: Lei Xingfeng , Chen Yanhui , Qiao Mingtao , Tian Lidong , Zhang Qiuyu
Published: January 2016

A 35 wt% HBPSi polyimide film exhibits an ultralow dielectric permittivity (2.24), accompanied by the most desirable comprehensive properties.
Correction: Division time-based amplifiers for stochastic gene expression
Authors: Wang Haohua , Yuan Zhanjiang , Liu Peijiang , Zhou Tianshou
Published: January 2016

Correction for ‘Division time-based amplifiers for stochastic gene expression’ by Haohua Wang et al., Mol. BioSyst., 2015, 11, 2417–2428.
Correction: Palladium-catalyzed oxidative annulation of in situ generated enones to pyrroles: a concise route to functionalized indoles
Authors: Guo Tenglong , Jiang Quanbin , Yu Zhengkun
Published: January 2016

Correction for ‘Palladium-catalyzed oxidative annulation of in situ generated enones to pyrroles: a concise route to functionalized indoles’ by Tenglong Guo et al., Org. Chem. Front., 2015, 2, 1361–1365.
Influence of the carrier mobility distribution on the Hall and the Nernst effect measurements in n-type InSb
Authors: Madon B. , Wegrowe J.-E. , Drouhin H.-J. , Liu X. , Furdyna J. , Khodaparast G. A.
Published: January 2016

In this study, we report magneto-resistance measurements on an n-doped InSb film, to separate the contributions of the electrical currents from the heat currents. We have demonstrated a prototype for a magnetic field sensor which is powered by heat currents and does not require any electrical current. We fabricated two Hall bars, where a low frequency (f = 0.05 Hz) AC current, was applied between the two contacts in one of the Hall bars. Separating the f and 2f components of the voltage measured across the second Hall bar was used to distinguish between the electrical and the heat contributions to the electron currents. Our observations can be modeled using a Gaussian distribution of mobility within the sample.
A fiber-coupled quantum-dot on a photonic tip
Authors: Cadeddu Davide , Teissier Jean , Braakman Floris R. , Gregersen Niels , Stepanov Petr , Gérard Jean-Michel , Claudon Julien , Warburton Richard J. , Poggio Martino , Munsch Mathieu
Published: January 2016

We present the experimental realization of a quantum fiber-pigtail. The device consists of a semiconductor quantum-dot embedded into a conical photonic wire that is directly connected to the core of a fiber-pigtail. We demonstrate a photon collection efficiency at the output of the fiber of 5.8% and suggest realistic improvements for the implementation of a useful device in the context of quantum information. We also discuss potential applications in scanning probe microscopy. The approach is generic and transferable to other materials including diamond and silicon.
Extraction of elastic modulus of porous ultra-thin low-k films by two-dimensional finite-element simulations of nanoindentation
Authors: Okudur O. O. , Vanstreels K. , De Wolf I. , Hangen U.
Published: January 2016

Continuous scaling of integrated circuits has led to the introduction of highly porous low dielectric constant (low-k) materials, whose inferior mechanical properties raise concerns regarding the reliability of integrated circuits. Nanoindentation is proven to be a straightforward method to study mechanical properties of films. However, in the case of low-k, the measurement and analysis are complex due to the porous nature of the films and reduced film thicknesses which give rise to substrate effects. A methodology that combines nanoindentation experiments with finite-element simulations is proposed and validated in this study to extract the substrate-free elastic modulus of porous ultra-thin low-k films. Furthermore, it is shown that imperfections of the nanoindentation probe significantly affect the finite-element results. An effective analytical method that captures the actual nanoindenter behavior upon indentation is proposed by taking both tip radius and conical imperfections into account. Using this method combined with finite element modeling, the elastic modulus of sub-100 nm thick low-k films is successfully extracted. Standard indentation tests clearly overestimated the actual modulus for such thin films, which emphasizes the importance of the proposed methodology.
Comparative analysis of the effects of tantalum doping and annealing on atomic layer deposited (Ta2O5)x(Al2O3)1−x as potential gate dielectrics for GaN/AlxGa1−xN/GaN high electron mobility transistors
Authors: Partida-Manzanera T. , Roberts J. W. , Bhat T. N. , Zhang Z. , Tan H. R. , Dolmanan S. B. , Sedghi N. , Tripathy S. , Potter R. J.
Published: January 2016

This paper describes a method to optimally combine wide band gap Al2O3 with high dielectric constant (high-κ) Ta2O5 for gate dielectric applications. (Ta2O5)x(Al2O3)1−x thin films deposited by thermal atomic layer deposition (ALD) on GaN-capped AlxGa1−xN/GaN high electron mobility transistor (HEMT) structures have been studied as a function of the Ta2O5 molar fraction. X-ray photoelectron spectroscopy shows that the bandgap of the oxide films linearly decreases from 6.5 eV for pure Al2O3 to 4.6 eV for pure Ta2O5. The dielectric constant calculated from capacitance-voltage measurements also increases linearly from 7.8 for Al2O3 up to 25.6 for Ta2O5. The effect of post-deposition annealing in N2 at 600 °C on the interfacial properties of undoped Al2O3 and Ta-doped (Ta2O5)0.12(Al2O3)0.88 films grown on GaN-HEMTs has been investigated. These conditions are analogous to the conditions used for source/drain contact formation in gate-first HEMT technology. A reduction of the Ga-O to Ga-N bond ratios at the oxide/HEMT interfaces is observed after annealing, which is attributed to a reduction of interstitial oxygen-related defects. As a result, the conduction band offsets (CBOs) of the Al2O3/GaN-HEMT and (Ta2O5)0.16(Al2O3)0.84/GaN-HEMT samples increased by ∼1.1 eV to 2.8 eV and 2.6 eV, respectively, which is advantageous for n-type HEMTs. The results demonstrate that ALD of Ta-doped Al2O3 can be used to control the properties of the gate dielectric, allowing the κ-value to be increased, while still maintaining a sufficient CBO to the GaN-HEMT structure for low leakage currents.
Carrier localization length in edge-disordered graphene nanoribbons with sub-100 nm length
Authors: Takashima Kengo , Konabe Satoru , Yamamoto Takahiro
Published: January 2016

We theoretically and computationally examined carrier localization in semiconducting edge-disordered graphene nanoribbons (ED-GNRs) with sub-100 nm lengths that correspond to the typical gate length for field-effect transistors. We numerically found that the localization length of ED-GNRs is proportional to the square of ribbon width and inversely proportional to the edge-disorder concentration. Furthermore, we obtained an analytical formula of the localization length in terms of the GNR width and the roughness concentration.
Resolution enhancement in transmission electron microscopy with 60-kV monochromated electron source
Authors: Morishita Shigeyuki , Mukai Masaki , Suenaga Kazutomo , Sawada Hidetaka
Published: January 2016

Transmission electron microscopy (TEM) at low accelerating voltages is useful to obtain images with low irradiation damage. For a low accelerating voltage, linear information transfer, which determines the resolution for observation of single-layered materials, is largely limited by defocus spread, which improves when a narrow energy spread is used in the electron source. In this study, we have evaluated the resolution of images obtained at 60 kV by TEM performed with a monochromated electron source. The defocus spread has been evaluated by comparing diffractogram tableaux from TEM images obtained under nonmonochromated and monochromated illumination. The information limits for different energy spreads were precisely measured by using diffractograms with a large beam tilt. The result shows that the information limit reaches 0.1 nm with an energy width of 0.10 eV. With this monochromated source and a higher-order aberration corrector, we have obtained images of single carbon atoms in a graphene sheet by TEM at 60 kV.
Defect-engineered optical bandgap in self-assembled TiO2 nanorods on Si pyramids
Authors: Saini C. P. , Barman A. , Satpati B. , Bhattacharyya S. R. , Kanjilal D. , Kanjilal A.
Published: January 2016

Transformation of self-assembled crystalline TiO2 nanorods to amorphous layer, and the corresponding impact on optical-bandgap (Eg) on Si pyramids are investigated by irradiating with 50 keV Ar+-ions. Initially, Eg is found to be reduced from 3.23 to 2.94 eV up to a fluence of 1 × 1016 ions/cm2, and discussed in terms of the rise in oxygen vacancies (VO). However, a sudden increase in Eg to 3.38 eV is detected at a fluence of 1 × 1017 ions/cm2 through evolution of voids by over-saturating VO, manifesting the appearance of degenerate states by shifting the Fermi level above the conduction band minimum via Burstein-Moss effect.
Contrasting and complex evolutionary histories within the terapontid grunter genus Hephaestus revealed by nuclear and mitochondrial genes
Authors: Pusey Bradley J. , Bentley Andrew , Burrows Damien , Perna Colton , Davis Aaron , Hughes Jane
Published: January 2016

Contrasting evolutionary histories may be revealed by mitochondrial and nuclear information. Divergent New Guinean and eastern and western Australian lineages of Hephaestus fuliginosus (sooty grunter) were detected using mitochondrial data, with the extent of divergence consistent with cryptic speciation events. However, this phylogeographic pattern was not supported by nuclear gene data, and evidence for cryptic speciation appears driven almost entirely by introgression between H. fuliginosus and congeners on the periphery of its distribution (e.g. with H. tulliensis, H. jenkinsi or H. roemeri). Hephaestus fuliginosus is a single species with a complex evolutionary history. Introgression on the eastern coast is consistent with transfer of the mitochondrial genome of the resident species (H. tulliensis) to the invading species (H. fuliginosus) and may have provided the metabolic capacity for H. fuliginosus to spread into the cooler rainforest environment of the Wet Tropics region. Mitochondrial and nuclear analyses both identified the genus Hephaestus as polyphyletic with H. carbo and H. habbemai placed in a clade with Leiopotherapon unicolor and Amniataba percoides. The present study demonstrated the need to consider a variety of genetic information when assessing species identity in a widespread species and the need for a systematic revision of the genus and family as a whole.
Avoid predation or take risks in basic activities? Predator–prey relationship in subtropical streams between decapods and caddisflies
Authors: Cerezer Cristina , Biasi Cristiane , Cogo Gláucia Bolzan , Santos Sandro
Published: January 2016

The objective of the present study was to analyse the movement, feeding and case-building behaviours of Phylloicus in the presence and absence of a likely decapod predator, Aegla longirostri. We used aquaria divided by a perforated acrylic plate, with one side containing a Phylloicus and the other containing A. longirostri. Movement was quantified through the time spent in active movement, feeding was quantified through the amount of consumed leaves and the case-building was assessed by comparing the number of leaf discs selected of each plant species. The Phylloicus movement activity was affected by A. longirostri, being higher in the predator absence than in its presence. The caddisfly feeding behaviour was not affected by the presence of the crab. Phylloicus was selective in the choice of plant species for case-building; in the presence of the predator, harder discs were more often employed, whereas softer and less resistant discs were chosen in the absence of the predator. The anti-predator responses of caddisfly demonstrated that they are able to detect the presence of crabs and modify their activities, thereby increasing their chances of survival.
Covert digital manipulation of vocal emotion alter speakers’ emotional states in a congruent direction
Authors: Aucouturier Jean-Julien , Johansson Petter , Hall Lars , Segnini Rodrigo , Mercadié Lolita , Watanabe Katsumi
Published: January 2016

Significance

We created a digital audio platform to covertly modify the emotional tone of participants’ voices while they talked toward happiness, sadness, or fear. Independent listeners perceived the transformations as natural examples of emotional speech, but the participants remained unaware of the manipulation, indicating that we are not continuously monitoring our own emotional signals. Instead, as a consequence of listening to their altered voices, the emotional state of the participants changed in congruence with the emotion portrayed. This result is the first evidence, to our knowledge, of peripheral feedback on emotional experience in the auditory domain. This finding is of great significance, because the mechanisms behind the production of vocal emotion are virtually unknown.
Gain-of-function mutations of
Ptpn11
(Shp2) cause aberrant mitosis and increase susceptibility to DNA damage-induced malignancies
Authors: Liu Xia , Zheng Hong , Li Xiaobo , Wang Siying , Meyerson Howard J. , Yang Wentian , Neel Benjamin G. , Qu Cheng-Kui
Published: January 2016

Significance

Genetic mutations of protein tyrosine phosphatase nonreceptor type 11
Ptpn11
(Shp2) are associated with childhood leukemias and solid tumors. The mechanisms by which
Ptpn11
mutations induce malignancies are not fully understood. In this study, we demonstrate that
Ptpn11
disease mutations disturb mitosis and cytokinesis, causing chromosomal instability and greatly increased susceptibility to DNA damage-induced malignancies. This finding reveals a novel mechanism by which deregulation of Shp2 induces malignancies and has important clinical implications. Given that
Ptpn11
mutations enhance DNA damage-induced tumorigenesis, caution should be taken when considering DNA-damaging preconditioning for stem cell transplantation therapy or DNA-damaging chemotherapy for
Ptpn11
-associated malignancies, especially in Noonan syndrome patients with germ-line
Ptpn11
mutations, as the risk of therapy-induced malignancies in these patients may be increased.
Stochastic modeling reveals an evolutionary mechanism underlying elevated rates of childhood leukemia
Authors: Rozhok Andrii I. , Salstrom Jennifer L. , DeGregori James
Published: January 2016

Significance

Elevated incidence of childhood leukemia relative to young adult ages is difficult to explain from the standpoint of oncogenic mutation accumulation. We applied a stochastic Monte Carlo model of hematopoietic stem cell (HSC) clonal dynamics based on published age-dependent parameters of HSCs. Our modeling results demonstrate that childhood and adult HSC clonal dynamics differ by the factors that determine the number of cell divisions per clonal context. Late in life, positive selection leading to clonal expansions increases the number of cell divisions per clone, whereas in childhood a similar increase is achieved by the much higher HSC division frequencies and drift-affected clonal expansions. We provide a mathematical argument that the obtained clonal dynamics and cell division measurements can explain the age-dependent incidence of leukemia.
Private algorithms for the protected in social network search
Authors: Kearns Michael , Roth Aaron , Wu Zhiwei Steven , Yaroslavtsev Grigory
Published: January 2016

Significance

Motivated by tensions between data privacy for individual citizens, and societal priorities such as counterterrorism, we introduce a computational model that distinguishes between parties for whom privacy is explicitly protected, and those for whom it is not (the “targeted” subpopulation). Within this framework, we provide provably privacy-preserving algorithms for targeted search in social networks. We validate the utility of our algorithms with extensive computational experiments on two large-scale social network datasets.
Neotropical forest expansion during the last glacial period challenges refuge hypothesis
Authors: Leite Yuri L. R. , Costa Leonora P. , Loss Ana Carolina , Rocha Rita G. , Batalha-Filho Henrique , Bastos Alex C. , Quaresma Valéria S. , Fagundes Valéria , Paresque Roberta , Passamani Marcelo , Pardini Renata
Published: January 2016

Significance

The tropical forests of South America are among the most diverse and unique habitats in the world in terms of plant and animal species. One of the most popular explanations for this diversity and endemism is the idea that forests retracted and fragmented during glacial periods, forming ecological refuges, surrounded by dry lands or savannas. These historically stable forest refuges would have been responsible for maintaining the pattern of diversity and endemism observed today. Here, we show that the Atlantic Forest of eastern South America probably expanded, rather than contracted, during the last glacial period. In addition, the emerged Brazilian continental shelf played a major, yet neglected, role on the evolution of this biodiversity hotspot during the last glacial period.
Nuclear TRAF3 is a negative regulator of CREB in B cells
Authors: Mambetsariev Nurbek , Lin Wai W. , Stunz Laura L. , Hanson Brett M. , Hildebrand Joanne M. , Bishop Gail A.
Published: January 2016

Significance

Uniquely in B cells, deletion of the adaptor protein TRAF3 (TNF receptor-associated factor 3) causes enhanced survival; TRAF3 deficiency is observed in a substantial percentage of human B-cell malignancies. Here, we report that TRAF3 is a resident nuclear protein in B cells that regulates stability of the CREB (cAMP response element binding protein) transcription factor. This regulation is important for restraining B-cell survival by preventing transcription of prosurvival genes and may be a key mechanism by which loss of TRAF3 contributes to B-cell malignancies. Considering the high frequency ofTRAF3mutations in B-cell tumors, our findings of an important nuclear role for TRAF3 present a new paradigm in understanding both normal regulation of B-cell survival and pathogenesis of B-cell cancers.
Decanalization of wing development accompanied the evolution of large wings in high-altitude
Drosophila
Authors: Lack Justin B. , Monette Matthew J. , Johanning Evan J. , Sprengelmeyer Quentin D. , Pool John E.
Published: January 2016

Significance

Developmental buffering mechanisms that stabilize phenotypes against perturbations (such as harmful mutations or environmental stress) have previously been inferred. However, it is unclear whether this “canalization” can be maintained when adaptive evolution causes phenotypes and developmental processes to change. Here, we report a loss of canalization accompanying the evolution of larger wings in high-altitude fruit flies (
Drosophila melanogaster
). We redeploy a classic genetics technique (mutagenesis) to show that wing development of Ethiopian flies is less robust to new mutations and that large wing size is inherited together with decanalized wing development. These results represent the first example, to our knowledge, of adaptive evolution apparently undermining the developmental buffering of a recently evolved trait. Decanalized development, thus, represents a potential “cost of adaptation.”
Molecular mechanism of viomycin inhibition of peptide elongation in bacteria
Authors: Holm Mikael , Borg Anneli , Ehrenberg Måns , Sanyal Suparna
Published: January 2016

Significance

Antibiotics are widely used to treat bacterial infections, but their mechanisms of action are often poorly understood. Viomycin is a tuberactinomycin antibiotic used for treating multidrug-resistant tuberculosis. Using an in vitro translation system that displays kinetic rates comparable to those in living cells we have characterized the mechanism of action of viomycin and constructed a kinetic model for how viomycin inhibits the translocation step of the peptide elongation cycle. Our results are vital for understanding the mechanism of the antimicrobial activity of viomycin and its sister drugs in living bacteria as well as resistance mechanisms against them, which can have strong implications for global health.
Close relation between quantum interference in molecular conductance and diradical existence
Authors: Tsuji Yuta , Hoffmann Roald , Strange Mikkel , Solomon Gemma C.
Published: January 2016

Significance

It might seem that the existence of a dramatic diminution in molecular conductance across a hydrocarbon (quantum interference, QI) would be unrelated to the existence of an important class of organic molecules with two electrons in two orbitals, diradicals. However, if you add two carbons to a planar π-electron hydrocarbon, you get a diradical if and only if there is a QI feature in conductance when two electrodes are attached to the molecule at the same sites. When you remove the two carbons where the electrodes are attached, you also generate a diradical. The connection, first empirically observed, is proven. Two kinds of diradicals, with different ground state spin consequences, are also easily distinguished by the relationship.
Neuregulin1 displayed on motor axons regulates terminal Schwann cell-mediated synapse elimination at developing neuromuscular junctions
Authors: Lee Young il , Li Yue , Mikesh Michelle , Smith Ian , Nave Klaus-Armin , Schwab Markus H. , Thompson Wesley J.
Published: January 2016

Significance

Refinement of synaptic connections occurs throughout the nervous system and is essential for its proper function. Significant gaps remain in our understanding of the mechanisms that mediate pruning of synaptic connections—a form of synaptic plasticity known as synapse elimination. Recently it has become clear there is significant glial cell involvement. The present study of the rodent neuromuscular junction addresses two outstanding questions involving this glial involvement: which molecules determine the Schwann cell behavior present during pruning, and whether these behaviors actually alter synaptic structure. Our findings identify axon-tethered neuregulin1 as a molecular determinant for Schwann cell-driven neuromuscular synaptic plasticity.
Origin of the
p
-process radionuclides
92
Nb and
146
Sm in the early solar system and inferences on the birth of the Sun
Authors: Lugaro Maria , Pignatari Marco , Ott Ulrich , Zuber Kai , Travaglio Claudia , Gyürky György , Fülöp Zsolt
Published: January 2016

Significance

Radioactive nuclei with half-lives of the order of millions of years were present in the solar system at its birth and can be used as clocks to measure the events that predated the birth of the Sun. Two of these nuclei are heavy and rich in protons and can be produced only by particular chains of nuclear reactions during some supernova explosions. We have used their abundances to derive that at least 10 million years passed between the last of these explosions and the birth of the Sun. This means that the region where the Sun was born must have lived at least as long, which is possible only if it was very massive.
A dynamic Asp–Arg interaction is essential for catalysis in microsomal prostaglandin E
2
synthase
Authors: Brock Joseph S. , Hamberg Mats , Balagunaseelan Navisraj , Goodman Michael , Morgenstern Ralf , Strandback Emilia , Samuelsson Bengt , Rinaldo-Matthis Agnes , Haeggström Jesper Z.
Published: January 2016

Significance

Microsomal prostaglandin E
2
synthase type 1 (mPGES-1) is an integral membrane protein that produces prostaglandin E
2
(PGE
2
), a mediator of inflammation, fever, pain, and tumorigenesis. Here we show that a serine residue implicated by the crystal structure is not required for function, whereas an arginine and aspartate residue in the active site, observed to be interacting within the crystal structure, are essential and mutually dependent during catalysis. We also demonstrate that a contact signaling network can interrupt the arginine–asparagine interaction and facilitate their participation in the chemical mechanism. Our work has broad implications for development of effective mPGES-1 inhibitors, potential drugs with clinical application in treatment of inflammatory diseases and cancer.
Intermediates in the assembly of mitotic checkpoint complexes and their role in the regulation of the anaphase-promoting complex
Authors: Kaisari Sharon , Sitry-Shevah Danielle , Miniowitz-Shemtov Shirly , Hershko Avram
Published: January 2016

Significance

The mitotic checkpoint system has important roles to ensure accurate segregation of chromosomes in mitosis. This system regulates the activity of the ubiquitin ligase Anaphase-Promoting Complex/Cyclosome (APC/C) by the formation of inhibitors including the Mitotic Checkpoint Complex (MCC). The mode of the assembly of MCC is not sufficiently understood, and it is also not known whether checkpoint complexes different from MCC also inhibit the APC/C. We find that complexes lacking Mad2, a protein component of MCC, have greatly reduced APC/C inhibitory action. On the other hand, a previously unknown species of MCC that contains an additional molecule of Cdc20 is a strong inhibitor of APC/C. These results reveal important molecular mechanisms in the action of the mitotic checkpoint system.
Calcium sensor regulation of the Ca
V
2.1 Ca
2+
channel contributes to short-term synaptic plasticity in hippocampal neurons
Authors: Nanou Evanthia , Sullivan Jane M. , Scheuer Todd , Catterall William A.
Published: January 2016

Significance

Information processing in the brain is mediated through synaptic connections between neurons, where neurotransmitter molecules released from presynaptic nerve terminals stimulate postsynaptic cells. Strength of synaptic transmission is increased transiently by short-term synaptic facilitation in response to repeated stimulation of nerve fibers. Synaptic transmission is initiated by calcium influx through calcium channels in presynaptic nerve terminals, which are regulated by calcium sensor proteins. We found that genetically modified mice in which we introduced a mutation in the binding site for calcium sensor proteins in presynaptic calcium channels have substantially altered facilitation in hippocampal synapses in response to pairs or trains of repetitive high-frequency stimuli. Our results show that disruption of calcium channel regulation by calcium sensor proteins impairs short-term facilitation in native synapses.
Altered short-term synaptic plasticity and reduced muscle strength in mice with impaired regulation of presynaptic Ca
V
2.1 Ca
2+
channels
Authors: Nanou Evanthia , Yan Jin , Whitehead Nicholas P. , Kim Min Jeong , Froehner Stanley C. , Scheuer Todd , Catterall William A.
Published: January 2016

Significance

Muscle contraction begins with release of neurotransmitter molecules from motor-nerve terminals onto muscle fibers. Strength of contraction depends on high-frequency stimulation of the nerve, which induces short-term increases in neurotransmitter release through presynaptic facilitation. Neurotransmitter release is initiated via calcium influx through voltage-gated calcium channels, which are regulated by calcium sensor (CaS) proteins. We found that genetically modified mice with a mutation in the binding site for CaS proteins on presynaptic calcium channels have reduced synaptic facilitation during high-frequency stimulation, resulting in reduced muscle strength, endurance, and coordination. Our results demonstrate critical roles for the regulation of calcium channels by CaS proteins in short-term presynaptic facilitation, with important consequences for motor control and muscle function in vivo.
Stress-dependent deformation behaviour in bulk nanocrystalline titanium–nickel alloys
Authors: Zhang Q. , Song W. P. , Li X. H. , Stolyarov V. V. , Zhang X. Y.
Published: January 2016

In this study, the deformation mechanisms operating with stress in bulk nanocrystalline (NC) titanium–nickel with an average grain size below a critical size of 10–20 nm have been investigated. We demonstrate a sequential variation of the deformation mechanism from grain boundary (GB) sliding and grain rotation to grain growth and dislocation activity with the increase of the deformation stress. These deformation mechanisms are different from the previous understanding that below a critical grain size of 10–20 nm, GB sliding and grain rotation govern plastic deformation of NC materials.
Formation of nanosized grain structure in martensitic 100Cr6 bearing steels upon rolling contact loading studied by atom probe tomography
Authors: Li Y. J. , Herbig M. , Goto S. , Raabe D.
Published: January 2016

To understand the origin of white etching cracks (WECs), a systematic microstructural characterisation in the regions affected from the near-surface region down to the subsurface layers where WECs occur is necessary. As a starting point, we focus on the near-surface region of an axial thrust bearing, made of martensitic 100Cr6 steel, to study the influence of rolling contact loading on the microstructure and the resulting distributions of the major alloying elements C and Cr using atom probe tomography. We find that upon rolling contact loading the original plate-like martensitic structure evolves into a nanosized equiaxed grain structure with C segregation up to 5 at.-% at the grain boundaries. Cementite particles, located at grain boundaries and triple junctions, undergo spheroidisation. The originally homogeneously distributed Cr becomes enriched in spheroidised cementite particles. The microstructural changes give strong hints that rolling contact loading induces plastic deformation and an increased temperature on the near-surface region.

This paper is part of a Themed Issue on Recent developments in bearing steels.
Scratch and wear resistance of nano-silica-modified silicate conversion coating on aluminium
Authors: Bahri H. , Danaee I. , Rashed G. R. , Dabiri A. R.
Published: January 2016

The silicate conversion coating was modified with nano-silica and applied on the surface of AA2024 by dip-coating technique. The mechanical properties of produced modified silicate layer were investigated by the pencil scratch hardness, cross-cut and abrasion resistance tests. The characterisation of coated surface before and after the tests was studied with optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy and atomic force microscopy. Addition of nano-silica to the silicate coating caused an enhancement in the SiO2:K2O ratio. The results showed that the homogeneity of coating surfaces increased in the presence of nano-silica. The wear and scratch resistance of the modified silicate layer improved against the sliding conditions. In addition, the adhesion of coating layer to the substrate metal increased.
Antioxidant and starch hydrolase inhibitory properties of extracts of the antidiabetic herb Pterocarpus marsupium
Authors: Lee Yian Hoon , Choo Candy , Waisundara Viduranga Y.
Published: January 2016

Pterocarpus marsupiumis a popular spice incorporated into culinary preparations around the world, which is also used for its antidiabetic treatment in traditional medicine. The objective of the study was to evaluate the antioxidant and starch hydrolase inhibitory properties ofPterocarpus marsupiumleaves. The total antioxidant capacity, total phenolics content, starch hydrolase inhibitory activities and superoxide dismutase mimetic (SODm) activity of various leaf extracts ofPterocarpus marsupiumwere studied. Extracts of dichloromethane (DCM), ethanol (EtOH), ethyl acetate (EtOAc), hexane (HEX), methanol (MeOH) and water were compared. The total phenolics contents of the extracts decreased in the order of water > EtOH > EtOAc > MeOH > DCM > HEX. The antioxidant and SODm activity values of the extracts decreased in the same order as the total phenolics contents, while the DPPH EC50values increased in the reverse order. Pterosupin and pterostilbene had the highest content out of all the phenolic compounds quantified across all solvent extracts. The highest starch hydrolase inhibitory activities were observed in the water extract.Pterocarpus marsupiumwas observed to be a good source of antioxidant compounds and therapeutic properties.
Class III myosins shape the auditory hair bundles by limiting microvilli and stereocilia growth
Authors: Lelli Andrea , Michel Vincent , Boutet de Monvel Jacques , Cortese Matteo , Bosch-Grau Montserrat , Aghaie Asadollah , Perfettini Isabelle , Dupont Typhaine , Avan Paul , El-Amraoui Aziz , Petit Christine
Published: January 2016

The precise architecture of hair bundles, the arrays of mechanosensitive microvilli-like stereocilia crowning the auditory hair cells, is essential to hearing. Myosin IIIa, defective in the late-onset deafness form DFNB30, has been proposed to transport espin-1 to the tips of stereocilia, thereby promoting their elongation. We show that Myo3a−/−Myo3b−/− mice lacking myosin IIIa and myosin IIIb are profoundly deaf, whereas Myo3a-cKO Myo3b−/− mice lacking myosin IIIb and losing myosin IIIa postnatally have normal hearing. Myo3a−/−Myo3b−/− cochlear hair bundles display robust mechanoelectrical transduction currents with normal kinetics but show severe embryonic abnormalities whose features rapidly change. These include abnormally tall and numerous microvilli or stereocilia, ungraded stereocilia bundles, and bundle rounding and closure. Surprisingly, espin-1 is properly targeted to Myo3a−/−Myo3b−/− stereocilia tips. Our results uncover the critical role that class III myosins play redundantly in hair-bundle morphogenesis; they unexpectedly limit the elongation of stereocilia and of subsequently regressing microvilli, thus contributing to the early hair bundle shaping.
Carbenoxolone inhibits Pannexin1 channels through interactions in the first extracellular loop
Authors: Michalski Kevin , Kawate Toshimitsu
Published: January 2016

Pannexin1 (Panx1) is an ATP release channel important for controlling immune responses and synaptic strength. Various stimuli including C-terminal cleavage, a high concentration of extracellular potassium, and voltage have been demonstrated to activate Panx1. However, it remains unclear how Panx1 senses and integrates such diverse stimuli to form an open channel. To provide a clue on the mechanism underlying Panx1 channel gating, we investigated the action mechanism of carbenoxolone (CBX), the most commonly used small molecule for attenuating Panx1 function triggered by a wide range of stimuli. Using a chimeric approach, we discovered that CBX reverses its action polarity and potentiates the voltage-gated channel activity of Panx1 when W74 in the first extracellular loop is mutated to a nonaromatic residue. A systematic mutagenesis study revealed that conserved residues in this loop also play important roles in CBX function, potentially by mediating CBX binding. We extended our experiments to other Panx1 inhibitors such as probenecid and ATP, which also potentiate the voltage-gated channel activity of a Panx1 mutant at position 74. Notably, probenecid alone can activate this mutant at a resting membrane potential. These data suggest that CBX and other inhibitors, including probenecid, attenuate Panx1 channel activity through modulation of the first extracellular loop. Our experiments are the first step toward identifying a previously unknown mode of CBX action, which provide insight into the role of the first extracellular loop in Panx1 channel gating.
Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders
Authors: Bocksteins Elke
Published: January 2016

Members of the electrically silent voltage-gated K+ (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K+ channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.
Loss of the smallest subunit of cytochrome c oxidase, COX8A, causes Leigh-like syndrome and epilepsy
Authors: Hallmann Kerstin , Kudin Alexei P. , Zsurka Gábor , Kornblum Cornelia , Reimann Jens , Stüve Burkhard , Waltz Stephan , Hattingen Elke , Thiele Holger , Nürnberg Peter , Rüb Cornelia , Voos Wolfgang , Kopatz Jens , Neumann Harald , Kunz Wolfram S.
Published: January 2016

Isolated cytochrome c oxidase (complex IV) deficiency is one of the most frequent respiratory chain defects in humans and is usually caused by mutations in proteins required for assembly of the complex. Mutations in nuclear-encoded structural subunits are very rare. In a patient with Leigh-like syndrome presenting with leukodystrophy and severe epilepsy, we identified a homozygous splice site mutation in COX8A, which codes for the ubiquitously expressed isoform of subunit VIII, the smallest nuclear-encoded subunit of complex IV. The mutation, affecting the last nucleotide of intron 1, leads to aberrant splicing, a frame-shift in the highly conserved exon 2, and decreased amount of the COX8A transcript. The loss of the wild-type COX8A protein severely impairs the stability of the entire cytochrome c oxidase enzyme complex and manifests in isolated complex IV deficiency in skeletal muscle and fibroblasts, similar to the frequent c.845_846delCT mutation in the assembly factor SURF1 gene. Stability and activity of complex IV could be rescued in the patient’s fibroblasts by lentiviral expression of wild-type COX8A. Our findings demonstrate that COX8A is indispensable for function of human complex IV and its mutation causes human disease.
Clinical Practice Guideline for the Management of Candidiasis: 2016 Update by the Infectious Diseases Society of America
Authors: Pappas Peter G. , Kauffman Carol A. , Andes David R. , Clancy Cornelius J. , Marr Kieren A. , Ostrosky-Zeichner Luis , Reboli Annette C. , Schuster Mindy G. , Vazquez Jose A. , Walsh Thomas J. , Zaoutis Theoklis E. , Sobel Jack D.
Published: January 2016

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.
Human Cytomegalovirus Up-Regulates Endothelin Receptor Type B: Implication for Vasculopathies?
Authors: Yaiw Koon-Chu , Mohammad Abdul-Aleem , Costa Helena , Taher Chato , Badrnya Sigrun , Assinger Alice , Wilhelmi Vanessa , Ananthaseshan Sharan , Estekizadeh Atosa , Davoudi Belghis , Ovchinnikova Olga , Shlyakhto Eugene , Rafnsson Arnar , Khan Zahidul , Butler Lynn , Rahbar Afsar , Pernow John , Söderberg-Nauclér Cecilia
Published: January 2016

Background.  Both endothelin receptor type B ([ETBR], a G protein-coupled receptor that mediates the vascular effects of the potent vasoconstrictor endothelin-1) and human cytomegalovirus ([HCMV], a ubiquitous herpesvirus) have been implicated in the pathogenesis of cardiovascular disease (CVD). The effects of HCMV infection on ETBR expression are unknown. We hypothesized that HCMV may contribute to the pathogenesis of CVD via ETBR modulation.

Methods.  Human CMV effects on ETBR were studied in vitro in endothelial cells (ECs) and smooth muscle cells (SMCs) and ex vivo in human carotid plaque tissue specimens. Expression of ETBR and viral immediate-early were quantified using quantitative polymerase chain reaction. Functional consequences after ETBR blockade in ECs were examined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide proliferation, wound healing, tube formation, and flow adhesion assays.

Results.  Human CMV is capable of upregulating both ETBR mRNA and protein expression in ECs and SMCs. The ETBR was also abundantly expressed in ECs, foam cells, and SMCs, and, more importantly, in HCMV-positive cells in human carotid plaques. Endothelin receptor type B blockade led to decreased proliferation and reduced tumor necrosis factor α-mediated leukocyte recruitment in both uninfected and HCMV-infected ECs. Direct HCMV infection was antimigratory and antiangiogenic in ECs.

Conclusions.  Human CMV may contribute to CVD via ETBR induction.