bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated GNSS Attitude and Position Determination based on an Affine Constrained Model
Authors: Liu Haiying , Xu Lei , Meng Xiaolin , Chen Xibei , Li Junyi
Published: August 2017

Global Navigation Satellite System (GNSS) attitude determination and positioning play an important role in many navigation applications. However, the two GNSS-based problems are usually treated separately. This ignores the constraint information of the GNSS antenna array and the accuracy is limited. To improve the performance of navigation, an integrated attitude and position determination method based on an affine constraint model is presented. In the first part, the GNSS array model and affine constrained attitude determination method are compared with the unconstrained methods. Then the integrated attitude and position determination method is presented. The performance of the proposed method is tested with a series of static data and dynamic experimental GNSS data. The results show that the proposed method can improve the success rate of ambiguity resolution to further improve the accuracy of attitude determination and relative positioning compared to the unconstrained methods.
Asymptotic Enumeration of Difference Matrices over Cyclic Groups
Authors: MONTGOMERY AARON M.
Published: August 2017

We identify a relationship between a certain family of random walks on Euclidean lattices and difference matrices over cyclic groups. We then use the techniques of Fourier analysis to estimate the return probabilities of these random walks, which in turn yields the asymptotic number of difference matrices over cyclic groups as the number of columns increases.
Super-Exponential Extinction Time of the Contact Process on Random Geometric Graphs
Authors: CAN VAN HAO
Published: August 2017

In this paper we prove lower and upper bounds for the extinction time of the contact process on random geometric graphs with connection radius tending to infinity. We obtain that for any infection rate λ > 0, the contact process on these graphs survives a time super-exponential in the number of vertices.
Packing Loose Hamilton Cycles
Authors: FERBER ASAF , LUH KYLE , MONTEALEGRE DANIEL , NGUYEN OANH
Published: August 2017

A subsetCof edges in ak-uniform hypergraphHis aloose Hamilton cycleifCcovers all the vertices ofHand there exists a cyclic ordering of these vertices such that the edges inCare segments of that order and such that every two consecutive edges share exactly one vertex. The binomial randomk-uniform hypergraphHkn,phas vertex set [n] and an edge setEobtained by adding eachk-tuplee∈ ($\binom{[n]}{k}$) toEwith probabilityp, independently at random.

Here we consider the problem of finding edge-disjoint loose Hamilton cycles covering all buto(|E|) edges, referred to as thepacking problem. While it is known that the threshold probability of the appearance of a loose Hamilton cycle inHkn,pis$p=\Theta\biggl(\frac{\log n}{n^{k-1}}\biggr),$the best known bounds for the packing problem are aroundp= polylog(n)/n. Here we make substantial progress and prove the following asymptotically (up to a polylog(n) factor) best possible result: forp≥ logCn/nk−1, a randomk-uniform hypergraphHkn,pwith high probability contains$N:=(1-o(1))\frac{\binom{n}{k}p}{n/(k-1)}$edge-disjoint loose Hamilton cycles.

Our proof utilizes and modifies the idea of ‘online sprinkling’ recently introduced by Vu and the first author.
“ArgumenteHin, ArgumenteHer.” Regularity and Idiomaticity in GermanN Hin,N Her
Authors: Finkbeiner Rita
Published: August 2017

This paper seeks to find the best linguistic analysis of the German semispecified, productive patternN hin, N her(for example,Krieg hin, Krieg her, es muss eine gute Show werden‘War or no war, it must be a good show’). The basic question is whether the properties ofN hin, N hercan be accounted for in a rule-based approach or whether they are to be regarded as idiosyncratic properties of this construction. One of the characteristic features ofN hin, N heris the identity of the nouns. This raises the question of whether or notN hin, N heris an instance of syntactic reduplication. It is shown that rule-based copying accounts fail when they are applied to the case ofN hin, N her. The paper argues for an alternative, constructionist account ofN hin, N her, which is able to cover both regular and idiosyncratic aspects of the construction in a systematic fashion. However, the paper goes beyond a standard constructionist account by also arguing that the idiosyncratic features of the construction can be further explained if one takes into account general pragmatic principles. This requires a theory that incorporates a systematic interface with pragmatics.*
The Diachrony of Semantic Gender Agreement: Findings from Middle Dutch
Authors: Kraaikamp Margot
Published: August 2017

This paper presents the results of a corpus study of pronominal gender agreement in Middle Dutch. In present-day Dutch and in several other Germanic varieties, pronouns show semantic gender agreement that is based on the degree of individuation of the referent. Dutch pronouns show variation between this type of agreement and lexical gender agreement. This study investigates how old semantic agreement based on individuation is. In particular, it aims to answer the question of whether semantic agreement has developed in response to the change from the Germanic three-gender system to a two-gender system or dates back to before this change. The results show that agreement based on individuation already existed in Middle Dutch, when the original three-gender system was still in place. This shows that this type of agreement did not develop in response to the change from three to two nominal genders. The semantic interpretation of the genders along the lines of individuation apparently existed already and could be an old Germanic, possibly Indo-European, feature. What seems to have changed over time is the proportion of semantic to lexical agreement, as semantic agreement appears to occur more frequently in present-day Dutch than in Middle Dutch. This shift in agreement preference may be due to the loss of adnominal gender marking and the resulting reduced visibility of lexical gender in the noun phrase.
Global Populisms and Their Impact
Authors: Grzymala-Busse Anna
Published: August 2017

Populism is on the rise: but to understand this phenomenon, we should first clearly conceptualize it and recognize that populism takes on different forms in various historical and political contexts. These “populisms” pose a threat to modern liberal democracy. As Poland and Hungary show, populists exclude entire swathes of society from the polity, and undermine the formal institutions and the informal norms of democracy.
Assessing Self-Efficacy in Presentation and Moderation	Skills
Authors: Ringeisen Tobias , Rohrmann Sonja , Bürgermeister Anika , Tibubos Ana N.
Published: August 2017

Abstract. By means of two studies, a self-report measure to assess self-efficacy in presentation and moderation skills, the SEPM scales, was validated. In study 1, factorial and construct validity were examined. A sample of 744 university students (41% females; more than 50% between 20 and 25 years) completed newly constructed self-efficacy items. Confirmatory factor analyses (CFAs) substantiated two positively correlated factors, presentation (SEPM-P) and moderation self-efficacy (SEPM-M). Each factor consists of eight items. The correlation patterns between the two SEPM subscales and related constructs such as extraversion, the preference for cooperative learning, and conflict management indicated adequate construct validity. In study 2, criterion validity was determined by means of latent change modeling. One hundred sixty students ( Mage = 24.40, SD = 4.04; 61% females) took part in a university course to foster key competences and completed the SEPM scales at the beginning and the end of the semester. Presentation and moderation self-efficacy increased significantly over time of which the latter was positively associated with the performance in a practical moderation exam. Across both studies, reliability of the scales was high, ranging from McDonald’s ω .80 to .88.
Methanethiol-dependent dimethylsulfide production in soil environments
Authors: Carrión Ornella , Pratscher Jennifer , Curson Andrew R J , Williams Beth T , Rostant Wayne G , Murrell J Colin , Todd Jonathan D
Published: August 2017

Dimethylsulfide (DMS) is an environmentally important trace gas with roles in sulfur cycling, signalling to higher organisms and in atmospheric chemistry. DMS is believed to be predominantly produced in marine environments via microbial degradation of the osmolyte dimethylsulfoniopropionate (DMSP). However, significant amounts of DMS are also generated from terrestrial environments, for example, peat bogs can emit ~6 μmol DMS m−2 per day, likely via the methylation of methanethiol (MeSH). A methyltransferase enzyme termed ‘MddA’, which catalyses the methylation of MeSH, generating DMS, in a wide range of bacteria and some cyanobacteria, may mediate this process, as the mddA gene is abundant in terrestrial metagenomes. This is the first study investigating the functionality of MeSH-dependent DMS production (Mdd) in a wide range of aerobic environments. All soils and marine sediment samples tested produced DMS when incubated with MeSH. Cultivation-dependent and cultivation-independent methods were used to assess microbial community changes in response to MeSH addition in a grassland soil where 35.9% of the bacteria were predicted to contain mddA. Bacteria of the genus Methylotenera were enriched in the presence of MeSH. Furthermore, many novel Mdd+ bacterial strains were isolated. Despite the abundance of mddA in the grassland soil, the Mdd pathway may not be a significant source of DMS in this environment as MeSH addition was required to detect DMS at only very low conversion rates.
Gap-state engineering of visible-light-active ferroelectrics for photovoltaic applications
Authors: Matsuo Hiroki , Noguchi Yuji , Miyayama Masaru
Published: August 2017

Photoferroelectrics offer unique opportunities to explore light energy conversion based on their polarization-driven carrier separation and above-bandgap voltages. The problem associated with the wide bandgap of ferroelectric oxides, i.e., the vanishingly small photoresponse under visible light, has been overcome partly by bandgap tuning, but the narrowing of the bandgap is, in principle, accompanied by a substantial loss of ferroelectric polarization. In this article, we report an approach, ‘gap-state’ engineering, to produce photoferroelectrics, in which defect states within the bandgap act as a scaffold for photogeneration. Our first-principles calculations and single-domain thin-film experiments of BiFeO3 demonstrate that gap states half-filled with electrons can enhance not only photocurrents but also photovoltages over a broad photon-energy range that is different from intermediate bands in present semiconductor-based solar cells. Our approach opens a promising route to the material design of visible-light-active ferroelectrics without sacrificing spontaneous polarization.
Erratum: A hitchhiker’s guide to an ISS experiment in under 9 months
Authors: Nadir Andrei James
Published: August 2017

A correction to this article has been published and is linked from the HTML version of this article.
Mapping sulphadoxine-pyrimethamine-resistant Plasmodium falciparum malaria in infected humans and in parasite populations in Africa
Authors: Okell Lucy C. , Griffin Jamie T. , Roper Cally
Published: August 2017

Intermittent preventive treatment (IPT) with sulphadoxine-pyrimethamine in vulnerable populations reduces malaria morbidity in Africa, but resistance mutations in the parasite dhps gene (combined with dhfr mutations) threaten its efficacy. We update a systematic review to map the prevalence of K540E and A581G mutations in 294 surveys of infected humans across Africa from 2004-present. Interpreting these data is complicated by multiclonal infections in humans, especially in high transmission areas. We extend statistical methods to estimate the frequency, i.e. the proportion of resistant clones in the parasite population at each location, and so standardise for varying transmission levels. Both K540E and A581G mutations increased in prevalence and frequency in 60% of areas after 2008, highlighting the need for ongoing surveillance. Resistance measures within countries were similar within 300 km, suggesting an appropriate spatial scale for surveillance. Spread of the mutations tended to accelerate once their prevalence exceeded 10% (prior to fixation). Frequencies of resistance in parasite populations are the same or lower than prevalence in humans, so more areas would be classified as likely to benefit from IPT if similar frequency thresholds were applied. We propose that the use of resistance frequencies as well as prevalence measures for policy decisions should be evaluated.
Circulating microRNA profiles of Hendra virus infection in horses
Authors: Cowled Christopher , Foo Chwan-Hong , Deffrasnes Celine , Rootes Christina L. , Williams David T. , Middleton Deborah , Wang Lin-Fa , Bean Andrew G. D. , Stewart Cameron R.
Published: August 2017

Hendra virus (HeV) is an emerging zoonotic pathogen harbored by Australian mainland flying foxes. HeV infection can cause lethal disease in humans and horses, and to date all cases of human HeV disease have resulted from contact with infected horses. Currently, diagnosis of acute HeV infections in horses relies on the productive phase of infection when virus shedding may occur. An assay that identifies infected horses during the preclinical phase of infection would reduce the risk of zoonotic viral transmission during management of HeV outbreaks. Having previously shown that the host microRNA (miR)-146a is upregulated in the blood of HeV-infected horses days prior to the detection of viremia, we have profiled miRNAs at the transcriptome-wide level to comprehensively assess differences between infected and uninfected horses. Next-generation sequencing and the miRDeep2 algorithm identified 742 mature miRNA transcripts corresponding to 593 miRNAs in whole blood of six horses (three HeV-infected, three uninfected). Thirty seven miRNAs were differentially expressed in infected horses, two of which were validated by qRT-PCR. This study describes a methodology for the transcriptome-wide profiling of miRNAs in whole blood and supports the notion that measuring host miRNA expression levels may aid infectious disease diagnosis in the future.
A novel family of mammalian transmembrane proteins involved in cholesterol transport
Authors: Méndez-Acevedo Kevin M. , Valdes Victor Julián , Asanov Alexander , Vaca Luis
Published: August 2017

Cholesterol is an essential compound in mammalian cells because it is involved in a wide range of functions, including as a key component of membranes, precursor of important molecules such as hormones, bile acids and vitamin D. The cholesterol transport across the circulatory system is a well-known process in contrast to the intracellular cholesterol transport, which is poorly understood. Recently in our laboratory, we identified a novel protein in C. elegans involved in dietary cholesterol uptake, which we have named ChUP-1. Insillicoanalysis identified two putative orthologue candidate proteins in mammals. The proteins SIDT1 and SIDT2 share identity and conserved cholesterol binding (CRAC) domains with C. elegans ChUP-1. Both mammalian proteins are annotated as RNA transporters in databases. In the present study, we show evidence indicating that SIDT1 and SIDT2 not only do not transport RNA, but they are involved in cholesterol transport. Furthermore, we show that single point mutations directed to disrupt the CRAC domains of both proteins prevent FRET between SIDT1 and SIDT2 and the cholesterol analogue dehydroergosterol (DHE) and alter cholesterol transport.
A few-emitter solid-state multi-exciton laser
Authors: Lichtmannecker S. , Florian M. , Reichert T. , Blauth M. , Bichler M. , Jahnke F. , Finley J. J. , Gies C. , Kaniber M.
Published: August 2017

We report on non-conventional lasing in a photonic-crystal nanocavity that operates with only four solid-state quantum-dot emitters. In a comparison between microscopic theory and experiment, we demonstrate that irrespective of emitter detuning, lasing with$${g}^{\mathrm{(2)}}=1$$g(2)=1is facilitated by means of emission from dense-lying multi-exciton states. In the spontaneous-emission regime we find signatures for radiative coupling between the quantum dots. The realization of different multi-exciton states at different excitation powers and the presence of electronic inter-emitter correlations are reflected in a pump-rate dependence of theβ-factor.
Limits of Resolution and Sensitivity of Proton Detected MAS Solid-State NMR Experiments at 111 kHz in Deuterated and Protonated Proteins
Authors: Xue Kai , Sarkar Riddhiman , Motz Carina , Asami Sam , Camargo Diana C. Rodriguez , Decker Venita , Wegner Sebastian , Tosner Zdenek , Reif Bernd
Published: August 2017

MAS solid-state NMR is capable of determining structures of protonated solid proteins using proton-detected experiments. These experiments are performed at MAS rotation frequency of around 110 kHz, employing 0.5 mg of material. Here, we compare 1H, 13C correlation spectra obtained from protonated and deuterated microcrystalline proteins at MAS rotation frequency of 111 kHz, and show that the spectral quality obtained from deuterated samples is superior to those acquired using protonated samples in terms of resolution and sensitivity. In comparison to protonated samples, spectra obtained from deuterated samples yield a gain in resolution on the order of 3 and 2 in the proton and carbon dimensions, respectively. Additionally, the spectrum from the deuterated sample yields approximately 2–3 times more sensitivity compared to the spectrum of a protonated sample. This gain could be further increased by a factor of 2 by making use of stereospecific precursors for biosynthesis. Although the overall resolution and sensitivity of 1H, 13C correlation spectra obtained using protonated solid samples with rotation frequencies on the order of 110 kHz is high, the spectral quality is still poor when compared to the deuterated samples. We believe that experiments involving large protein complexes in which sensitivity is limiting will benefit from the application of deuteration schemes.
Common origin of methylenedioxy ring degradation and demethylation in bacteria
Authors: Takeda Hisashi , Ishikawa Kazuki , Yoshida Hinaka , Kasai Daisuke , Wakana Daigo , Fukuda Masao , Sato Fumihiko , Hosoe Tomoo
Published: August 2017

Plants produce many specific secondary metabolites as a response to environmental stress, especially biological stress. These compounds show strong biological activities and high stability against degradation by microbes and animals. Berberine, a benzylisoquinoline alkaloid, is found in many plant species and has strong antimicrobial activity, and is often included in traditional herbal medicines. We previously investigated how berberine is degraded in nature and we isolated two berberine-utilizing bacteria. In this study, we characterized the gene encoding the enzyme that degrades the 2,3-methylenedioxy ring of berberine; this ring is important for its activity and stability. Further characterization of several other berberine-utilizing bacteria and the genes encoding key demethylenation enzymes revealed that these enzymes are tetrahydrofolate dependent and similar to demethylation enzymes such as GcvT. Because the degradation of O-methyl groups or the methylenedioxy ring in phenolic compounds such as lignin, lignan and many other natural products, including berberine, is the key step for the catabolism of these compounds, our discovery reveals the common origin of the catabolism of these stable chemicals in bacteria.
A camelid single-domain antibody neutralizes botulinum neurotoxin A by blocking host receptor binding
Authors: Yao Guorui , Lam Kwok-ho , Weisemann Jasmin , Peng Lisheng , Krez Nadja , Perry Kay , Shoemaker Charles B. , Dong Min , Rummel Andreas , Jin Rongsheng
Published: August 2017

Antibody treatment is currently the only available countermeasure for botulism, a fatal illness caused by flaccid paralysis of muscles due to botulinum neurotoxin (BoNT) intoxication. Among the seven major serotypes of BoNT/A-G, BoNT/A poses the most serious threat to humans because of its high potency and long duration of action. Prior to entering neurons and blocking neurotransmitter release, BoNT/A recognizes motoneurons via a dual-receptor binding process in which it engages both the neuron surface polysialoganglioside (PSG) and synaptic vesicle glycoprotein 2 (SV2). Previously, we identified a potent neutralizing antitoxin against BoNT/A1 termed ciA-C2, derived from a camelid heavy-chain-only antibody (VHH). In this study, we demonstrate that ciA-C2 prevents BoNT/A1 intoxication by inhibiting its binding to neuronal receptor SV2. Furthermore, we determined the crystal structure of ciA-C2 in complex with the receptor-binding domain of BoNT/A1 (HCA1) at 1.68 Å resolution. The structure revealed that ciA-C2 partially occupies the SV2-binding site on HCA1, causing direct interference of HCA1 interaction with both the N-glycan and peptide-moiety of SV2. Interestingly, this neutralization mechanism is similar to that of a monoclonal antibody in clinical trials, despite that ciA-C2 is more than 10-times smaller. Taken together, these results enlighten our understanding of BoNT/A1 interactions with its neuronal receptor, and further demonstrate that inhibiting toxin binding to the host receptor is an efficient countermeasure strategy.
The HIV Genomic Incidence Assay Meets False Recency Rate and Mean Duration of Recency Infection Performance Standards
Authors: Park Sung Yong , Love Tanzy M. T. , Reynell Lucy , Yu Carl , Kang Tina Manzhu , Anastos Kathryn , DeHovitz Jack , Liu Chenglong , Kober Kord M. , Cohen Mardge , Mack Wendy J. , Lee Ha Youn
Published: August 2017

HIV incidence is a primary metric for epidemic surveillance and prevention efficacy assessment. HIV incidence assay performance is evaluated via false recency rate (FRR) and mean duration of recent infection (MDRI). We conducted a meta-analysis of 438 incident and 305 chronic specimens’ HIV envelope genes from a diverse global cohort. The genome similarity index (GSI) accurately characterized infection stage across diverse host and viral factors. All except one chronic specimen had GSIs below 0.67, yielding a FRR of 0.33 [0-0.98] %. We modeled the incidence assay biomarker dynamics with a logistic link function assuming individual variabilities in a Beta distribution. The GSI probability density function peaked close to 1 in early infection and 0 around two years post infection, yielding MDRI of 420 [361, 467] days. We tested the assay by newly sequencing 744 envelope genes from 59 specimens of 21 subjects who followed from HIV negative status. Both standardized residuals and Anderson-Darling tests showed that the test dataset was statistically consistent with the model biomarker dynamics. This is the first reported incidence assay meeting the optimal FRR and MDRI performance standards. Signatures of HIV gene diversification can allow precise cross-sectional surveillance with a desirable temporal range of incidence detection.
Human Lipoproteins at Model Cell Membranes: Effect of Lipoprotein Class on Lipid Exchange
Authors: Browning K. L. , Lind T. K. , Maric S. , Malekkhaiat-Häffner S. , Fredrikson G. N. , Bengtsson E. , Malmsten M. , Cárdenas M.
Published: August 2017

High and low density lipoproteins (HDL and LDL) are thought to play vital roles in the onset and development of atherosclerosis; the biggest killer in the western world. Key issues of initial lipoprotein (LP) interactions at cellular membranes need to be addressed including LP deposition and lipid exchange. Here we present a protocol for monitoring the in situ kinetics of lipoprotein deposition and lipid exchange/removal at model cellular membranes using the non-invasive, surface sensitive methods of neutron reflection and quartz crystal microbalance with dissipation. For neutron reflection, lipid exchange and lipid removal can be distinguished thanks to the combined use of hydrogenated and tail-deuterated lipids. Both HDL and LDL remove lipids from the bilayer and deposit hydrogenated material into the lipid bilayer, however, the extent of removal and exchange depends on LP type. These results support the notion of HDL acting as the ‘good’ cholesterol, removing lipid material from lipid-loaded cells, whereas LDL acts as the ‘bad’ cholesterol, depositing lipid material into the vascular wall.
Angulin proteins ILDR1 and ILDR2 regulate alternative pre-mRNA splicing through binding to splicing factors TRA2A, TRA2B, or SRSF1
Authors: Liu Yueyue , Nie Hongyun , Liu Chengcheng , Zhai Xiaoyan , Sang Qing , Wang Yanfei , Shi Deli , Wang Lei , Xu Zhigang
Published: August 2017

Angulin proteins are a group of evolutionally conserved type I transmembrane proteins that contain an extracellular Ig-like domain. In mammals, three angulin proteins have been identified, namely immunoglobulin-like domain containing receptor 1 (ILDR1), immunoglobulin-like domain containing receptor 2 (ILDR2), and lipolysis-stimulated lipoprotein receptor (LSR). All three proteins have been shown to localize at tight junctions (TJs) and are important for TJ formation. Mutations in ILDR1 gene have been shown to cause non-syndromic hearing loss (NSHL). In the present work, we show that ILDR1 binds to splicing factors TRA2A, TRA2B, and SRSF1, and translocates into the nuclei when the splicing factors are present. Moreover, ILDR1 affects alternative splicing of Tubulin delta 1 (TUBD1), IQ motif containing B1 (IQCB1), and Protocadherin 19 (Pcdh19). Further investigation show that ILDR2, but not LSR, also binds to the splicing factors and regulates alternative splicing. When endogenous ILDR1 and ILDR2 expression is knockdown with siRNAs in cultured cells, alternative splicing of TUBD1 and IQCB1 is affected. In conclusion, we show here that angulin proteins ILDR1 and ILDR2 are involved in alternative pre-mRNA splicing via binding to splicing factors TRA2A, TRA2B, or SRSF1.
GluA1 AMPAR subunit deletion reduces the hedonic response to sucrose but leaves satiety and conditioned responses intact
Authors: Austen Joseph M. , Sprengel Rolf , Sanderson David J.
Published: August 2017

The GluA1 subunit of the AMPA receptor has been implicated in schizophrenia. While GluA1 is important for cognition, it is not clear what the role of GluA1 is in hedonic responses that are relevant to the negative symptoms of disorders such as schizophrenia. Here, we tested mice that lack GluA1 (Gria1−/− mice) on consumption of sucrose solutions using a licking microstructure analysis. GluA1 deletion drastically reduced palatability (as measured by the mean lick cluster size) across a range of sucrose concentrations. Although initial lick rates were reduced, measures of consumption across long periods of access to sucrose solutions were not affected by GluA1 deletion and Gria1−/− mice showed normal satiety responses to high sucrose concentrations. GluA1 deletion also failed to impair flavour conditioning, in which increased intake of a flavour occurred as a consequence of prior pairing with a high sucrose concentration. These results demonstrate that GluA1 plays a role in responding on the basis of palatability rather than other properties, such as the automatic and learnt post-ingestive, nutritional consequences of sucrose. Therefore, Gria1−/− mice provide a potential model of anhedonia, adding converging evidence to the role of glutamatergic dysfunction in various symptoms of schizophrenia and related disorders.
Radiative recombination of confined electrons at the MgZnO/ZnO heterojunction interface
Authors: Choi Sumin , Rogers David J. , Sandana Eric V. , Bove Philippe , Teherani Ferechteh H. , Nenstiel Christian , Hoffmann Axel , McClintock Ryan , Razeghi Manijeh , Look David , Gentle Angus , Phillips Matthew R. , Ton-That Cuong
Published: August 2017

We investigate the optical signature of the interface in a single MgZnO/ZnO heterojunction, which exhibits two orders of magnitude lower resistivity and 10 times higher electron mobility compared with the MgZnO/Al2O3 film grown under the same conditions. These impressive transport properties are attributed to increased mobility of electrons at the MgZnO/ZnO heterojunction interface. Depth-resolved cathodoluminescence and photoluminescence studies reveal a 3.2 eV H-band optical emission from the heterointerface, which exhibits excitonic properties and a localization energy of 19.6 meV. The emission is attributed to band-bending due to the polarization discontinuity at the interface, which leads to formation of a triangular quantum well and localized excitons by electrostatic coupling.
MicroRNA-98 negatively regulates myocardial infarction-induced apoptosis by down-regulating Fas and caspase-3
Authors: Sun Chuan , Liu Huibin , Guo Jing , Yu Yang , Yang Di , He Fang , Du Zhimin
Published: August 2017

Acute myocardial infarction (MI) is the leading cause of sudden death worldwide. MicroRNAs (miRs) is a novel class of regulators of cardiovascular diseases such as MI. This study aimed to explore the role of miR-98 in MI and its underlying mechanisms. We found that miR-98 was downregulated both in infarcted and ischemic myocardium of MI mice as well as H2O2-treated neonatal rat ventricular myocytes (NRVCs). miR-98 overexpression remarkably increased cell viability and inhibited apoptosis of H2O2-treated NRVCs. Meanwhile, overexpression of miR-98 reversed H2O2-induced Bcl-2 downregulation and Bax elevation and significantly reduced JC-1 monomeric cells. Meanwhile, miR-98 overexpression attenuated the upregulation of Fas and caspase-3 in H2O2-treated cardiomyocytes at the mRNA and protein levels. Dual-luciferase reporter assay showed that miR-98 directly targeted to Fas 3′-UTR. Furthermore, MI mice injected with miR-98-agomir had a significant reduction of apoptotic cells, the serum LDH levels, myocardial caspase-3 activity, Fas and caspase-3 expression in heart tissues. Administration of miR-98-agomir also showed decreased infarct size and improved cardiac function. Collectively, miR-98 is downregulated in the MI heart and NRVCs in response to H2O2 stress, and miR-98 overexpression protects cardiomyocytes against apoptosis. Anti-apoptotic effects of miR-98 are associated with regulation of Fas/Caspase-3 apoptotic signal pathway.
Development of RNAi method for screening candidate genes to control emerald ash borer, Agrilus planipennis
Authors: Rodrigues Thais B. , Rieske Lynne K. , J. Duan Jian , Mogilicherla Kanakachari , Palli Subba R.
Published: August 2017

The ingestion of double-strand RNAs (dsRNA) targeting essential genes in an insect could cause mortality. Based on this principle, a new generation of insect control methods using RNA interference (RNAi) are being developed. In this work, we developed a bioassay for oral delivery of dsRNA to an invasive forest and urban tree pest, the emerald ash borer (EAB, Agrilus planipennis). EAB feeds and develops beneath the bark, killing trees rapidly. This behavior, coupled with the lack of a reliable artificial diet for rearing larvae and adults, make them difficult to study. We found that dsRNA is transported and processed to siRNAs by EAB larvae within 72 h after ingestion. Also, feeding neonate larvae with IAP (inhibitor of apoptosis) or COP (COPI coatomer, β subunit) dsRNA silenced their target genes and caused mortality. Both an increase in the concentration of dsRNA fed and sequential feeding of two different dsRNAs increased mortality. Here we provide evidence for successful RNAi in EAB, and demonstrate the development of a rapid and effective bioassay for oral delivery of dsRNA to screen additional genes.
Highly Sensitive, Engineered Magnetic Nanosensors to Investigate the Ambiguous Activity of Zika Virus and Binding Receptors
Authors: Shelby Tyler , Banerjee Tuhina , Zegar Irene , Santra Santimukul
Published: August 2017

The aim of this research is twofold: 1) to shed light on zika’s binding and entry mechanism while 2) demonstrating the effectiveness of our magnetic relaxation platform to achieve this goal. Magnetic relaxation-sensitive nanoparticles (MRNPs) are used in a novel fashion to analyze binding interactions between the zika envelope protein (ZENV) and proposed host cell receptors: AXL, HSP70, and TIM-1. Computational analysis is also utilized to examine these binding interactions for the first time. In addition, the role of crizotinib as a potential binding inhibitor is demonstrated and the possibility of ligand-independent phosphatidylserine-mediated binding is explored. Our findings suggest that while the extracellular domain of AXL has the highest affinity for ZENV; HSP70, TIM-1, and phosphatidylserine might also play active roles in zika tropism, which offers a potential explanation for the variety of zika-associated symptoms. This is, to our knowledge, the first time that MRNPs have been used to examine and quantify host-zika interactions. Our magnetic relaxation platform allows for timely and sensitive analysis of these intricate binding relationships, and it is easily customizable for further examination of additional host-pathogen interactions.
Suspended Liquid Subtractive Lithography: One-step generation of 3D channel geometries in viscous curable polymer matrices
Authors: Helmer D. , Voigt A. , Wagner S. , Keller N. , Sachsenheimer K. , Kotz F. , Nargang T. M. , Rapp B. E.
Published: August 2017

The miniaturization of synthesis, analysis and screening experiments is an important step towards more environmentally friendly chemistry, statistically significant biology and fast and cost-effective medicinal assays. The facile generation of arbitrary 3D channel structures in polymers is pivotal to these techniques. Here we present a method for printing microchannels directly into viscous curable polymer matrices by injecting a surfactant into the uncured material via a steel capillary attached to a 3D printer. We demonstrate this technique using polydimethylsiloxane (PDMS) one of the most widely used polymers for the fabrication of, e. g. microfluidic chips. We show that this technique which we term Suspended Liquid Subtractive Lithography (SLSL) is well suited for printing actuators, T-junctions and complex three dimensional structures. The formation of truly arbitrary channels in 3D could revolutionize the fabrication of miniaturized chips and will find broad application in biology, chemistry and medicine.
ssAAVs containing cassettes encoding SaCas9 and guides targeting hepatitis B virus inactivate replication of the virus in cultured cells
Authors: Scott Tristan , Moyo Buhle , Nicholson Samantha , Maepa Mohube Betty , Watashi Koichi , Ely Abdullah , Weinberg Marc S. , Arbuthnot Patrick
Published: August 2017

Management of infection with hepatitis B virus (HBV) remains a global health problem. Persistence of stable covalently closed circular DNA (cccDNA) during HBV replication is responsible for modest curative efficacy of currently licensed drugs. Novel gene editing technologies, such as those based on CRISPR/Cas9, provide the means for permanently disabling cccDNA. However, efficient delivery of antiviral sequences to infected hepatocytes is challenging. A limiting factor is the large size of sequences encoding Cas9 from Streptococcus pyogenes, and resultant incompatibility with the popular single stranded adeno-associated viral vectors (ssAAVs). We thus explored the utility of ssAAVs for delivery of engineered CRISPR/Cas9 of Staphylococcus aureus (Sa), which is encoded by shorter DNA sequences. Short guide RNAs (sgRNAs) were designed with cognates in the S open reading frame of HBV and incorporated into AAVs that also encoded SaCas9. Intended targeted mutation of HBV DNA was observed after transduction of cells with the all-in-one vectors. Efficacy against HBV-infected hNTCP-HepG2 cells indicated that inactivation of cccDNA was successful. Analysis of likely off-target mutagenesis revealed no unintended sequence changes. Use of ssAAVs to deliver all components required to disable cccDNA by SaCas9 is novel and the technology has curative potential for HBV infection.
Genuine antiplasticizing effect of water on a glass-former drug
Authors: Ruiz Guadalupe N. , Romanini Michela , Hauptmann Astrid , Loerting Thomas , Shalaev Evgenyi , Tamarit Josep Ll. , Pardo Luis C. , Macovez Roberto
Published: August 2017

Water is the most important plasticizer of biological and organic hydrophilic materials, which generally exhibit enhanced mechanical softness and molecular mobility upon hydration. The enhancement of the molecular dynamics upon mixing with water, which in glass-forming systems implies a lower glass transition temperature (T
g
), is considered a universal result of hydration. In fact, even in the cases where hydration or humidification of an organic glass-forming sample result in stiffer mechanical properties, the molecular mobility of the sample almost always increases with increasing water content, and its T
g
decreases correspondingly. Here, we present an experimental report of a genuine antiplasticizing effect of water on the molecular dynamics of a small-molecule glass former. In detail, we show that addition of water to prilocaine, an active pharmaceutical ingredient, has the same effect as that of an applied pressure, namely, a decrease in mobility and an increase of T
g
. We assign the antiplasticizing effect to the formation of prilocaine-H2O dimers or complexes with enhanced hydrogen bonding interactions.
Genomic surveillance reveals low prevalence of livestock-associated methicillin-resistant Staphylococcus aureus in the East of England
Authors: Harrison Ewan M. , Coll Francesc , Toleman Michelle S. , Blane Beth , Brown Nicholas M. , Török M. Estee , Parkhill Julian , Peacock Sharon J.
Published: August 2017

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an emerging problem in many parts of the world. LA-MRSA has been isolated previously from animals and humans in the United Kingdom (UK), but the prevalence is unknown. The aim of this study was to determine the prevalence and to describe the molecular epidemiology of LA-MRSA isolated in the East of England (broadly Cambridge and the surrounding area). We accessed whole genome sequence data for 2,283 MRSA isolates from 1,465 people identified during a 12-month prospective study between 2012 and 2013 conducted in the East of England, United Kingdom. This laboratory serves four hospitals and 75 general practices. We screened the collection for multilocus sequence types (STs) and for host specific resistance and virulence factors previously associated with LA-MRSA. We identified 13 putative LA-MRSA isolates from 12 individuals, giving an estimated prevalence of 0.82% (95% CI 0.47% to 1.43%). Twelve isolates were mecC-MRSA (ten CC130, one ST425 and one ST1943) and single isolate was ST398. Our data demonstrate a low burden of LA-MRSA in the East of England, but the detection of mecC-MRSA and ST398 indicates the need for vigilance. Genomic surveillance provides a mechanism to detect and track the emergence and spread of MRSA clones of human importance.
Seed dispersal by macaws shapes the landscape of an Amazonian ecosystem
Authors: Baños-Villalba Adrián , Blanco Guillermo , Díaz-Luque José A. , Dénes Francisco V. , Hiraldo Fernando , Tella José L.
Published: August 2017

Seed dispersal is one of the most studied plant–animal mutualisms. It has been proposed that the dispersal of many large-seeded plants from Neotropical forests was primarily conducted by extinct megafauna, and currently by livestock. Parrots can transport large fruits using their beaks, but have been overlooked as seed dispersers. We demonstrate that three macaws (Ara ararauna,A.glaucogularisandA.severus) are the main dispersers of the large-seeded motacú palmAttalea princeps, which is the biomass-dominant tree in the Bolivian Amazonian savannas. Macaws dispersed fruits at high rates (75–100% of fruits) to distant (up to 1200 m) perching trees, where they consumed the pulp and discarded entire seeds, contributing to forest regeneration and connectivity between distant forests islands. The spatial distribution of immature palms was positively associated to the proximity to macaws’ perching trees and negatively to the proximity to cattle paths. The disperser role of livestock, presumably a substitute for extinct megafauna, had little effect due to soil compaction, trampling and herbivory. Our results underscore the importance of macaws as legitimate, primary dispersers of large-seeded plants at long distances and, specifically, their key role in shaping the landscape structure and functioning of this Amazonian biome.
Exploiting nonlinear properties of pure and Sn-doped Bi2Te2Se for passive Q-switching of all-polarization maintaining ytterbium- and erbium-doped fiber lasers
Authors: Bogusławski Jakub , Kowalczyk Maciej , Iwanowski Przemysław , Hruban Andrzej , Diduszko Ryszard , Piotrowski Kazimierz , Dybko Krzysztof , Wojciechowski Tomasz , Aleszkiewicz Marta , Sotor Jarosław
Published: August 2017

Due to their broadband nonlinear optical properties, low-dimensional materials are widely used for pulse generation in fiber and solid-state lasers. Here we demonstrate novel materials, Bi2Te2Se (BTS) and Sn-doped Bi2Te2Se (BSTS), which can be used as a universal saturable absorbers for distinct spectral regimes. The material was mechanically exfoliated from a bulk single-crystal and deposited onto a side-polished fiber. We have performed characterization of the fabricated devices and employed them in polarization-maintaining ytterbium- and erbium-doped fiber lasers. This enabled us to obtain self-starting passively Q-switched regime at 1 µm and 1.56 µm. The oscillators emitted stable, linearly polarized radiation with the highest single pulse energy approaching 692 nJ. Both lasers are characterized by the best performance observed in all-polarization maintaining Q-switched fiber lasers with recently investigated new saturable absorbers, which was enabled by a very high damage threshold of the devices. This demonstrates the great potential of the investigated materials for the ultrafast photonics community.
Proton Transfer in Molten Lithium Carbonate: Mechanism and Kinetics by Density Functional Theory Calculations
Authors: Lei Xueling , Huang Kevin , Qin Changyong
Published: August 2017

Using static and dynamic density functional theory (DFT) methods with a cluster model of [(Li2CO3)8H]+, the mechanism and kinetics of proton transfer in lithium molten carbonate (MC) were investigated. The migration of proton prefers an inter-carbonate pathway with an energy barrier of 8.0 kcal/mol at the B3LYP/6-31 G(d,p) level, which is in good agreement with the value of 7.6 kcal/mol and 7.5 kcal/mol from experiment and FPMD simulation, respectively. At transition state (TS), a linkage of O–H–O involving O 2p and H 1 s orbitals is formed between two carbonate ions. The calculated trajectory of H indicates that proton has a good mobility in MC, oxygen can rotate around carbon to facilitate the proton migration, while the movement of carbon is very limited. Small variations on geometry and atomic charge were detected on the carbonate ions, implying that the proton migration is a synergetic process and the whole carbonate structure is actively involved. Overall, the calculated results indicate that MC exhibits a low energy barrier for proton conduction in IT-SOFCs.
Preparation and characterization of a new graphite superconductor: Ca0.5Sr0.5C6
Authors: Nishiyama Saki , Fujita Hidenori , Hoshi Masatoshi , Miao Xiao , Terao Takahiro , Yang Xiaofan , Miyazaki Takafumi , Goto Hidenori , Kagayama Tomoko , Shimizu Katsuya , Yamaoka Hitoshi , Ishii Hirofumi , Liao Yen-Fa , Kubozono Yoshihiro
Published: August 2017

We have produced a superconducting binary-elements intercalated graphite, CaxSr1−xCy, with the intercalation of Sr and Ca in highly-oriented pyrolytic graphite; the superconducting transition temperature, Tc, was ~3 K. The superconducting CaxSr1−xCy sample was fabricated with the nominal x value of 0.8, i.e., Ca0.8Sr0.2Cy. Energy dispersive X-ray (EDX) spectroscopy provided the stoichiometry of Ca0.5(2)Sr0.5(2)Cy for this sample, and the X-ray powder diffraction (XRD) pattern showed that Ca0.5(2)Sr0.5(2)Cy took the SrC6-type hexagonal-structure rather than CaC6-type rhombohedral-structure. Consequently, the chemical formula of CaxSr1−xCy sample could be expressed as ‘Ca0.5(2)Sr0.5(2)C6’. The XRD pattern of Ca0.5(2)Sr0.5(2)C6 was measured at 0–31 GPa, showing that the lattice shrank monotonically with increasing pressure up to 8.6 GPa, with the structural phase transition occurring above 8.6 GPa. The pressure dependence of Tc was determined from the DC magnetic susceptibility and resistance up to 15 GPa, which exhibited a positive pressure dependence of Tc up to 8.3 GPa, as in YbC6, SrC6, KC8, CaC6 and Ca0.6K0.4C8. The further application of pressure caused the rapid decrease of Tc. In this study, the fabrication and superconducting properties of new binary-elements intercalated graphite, CaxSr1−xCy, are fully investigated, and suitable combinations of elements are suggested for binary-elements intercalated graphite.
Neural correlates of proactive and reactive motor response inhibition of gambling stimuli in frequent gamblers
Authors: Brevers D. , He Q. , Keller B. , Noël X. , Bechara A.
Published: August 2017

We used functional magnetic resonance imaging to examine whether motivational-salient cues could exert a differential impact on proactive (the restrain of actions in preparation for stopping) and reactive (outright stopping) inhibition. Fourteen high-frequency poker players, and 14 matched non-gambler controls, performed a modified version of the stop-signal paradigm, which required participants to inhibit categorization of poker or neutral pictures. The probability that a stop-signal occurs (0%, 17%, 25%, 33%) was manipulated across blocks of trials, as indicated by the color of the computer screen. Behavioral analyses revealed that poker players were faster than controls in categorizing pictures across all levels of proactive motor response inhibition (go trials). Brain imaging analyses highlighted higher dorsal anterior cingulate cortex activation in poker players, as compared to controls, during reactive inhibition. These findings suggest that, due to their faster rates of stimulus discrimination, poker players might have recruited more cognitive resources than controls when required to stop their response (reactive inhibition). Nevertheless, no main effect of stimulus type was found, on either proactive or reactive inhibition. Additional studies are, therefore, needed in order to confirm that investigating the dynamics between reactive and proactive inhibition offers a discriminative analysis of inhibitory control toward motivational-salient cues.
Twisting of DNA Origami from Intercalators
Authors: Zadegan Reza M. , Lindau Elias G. , Klein William P. , Green Christopher , Graugnard Elton , Yurke Bernard , Kuang Wan , Hughes William L.
Published: August 2017

DNA nanostructures represent the confluence of materials science, computer science, biology, and engineering. As functional assemblies, they are capable of performing mechanical and chemical work. In this study, we demonstrate global twisting of DNA nanorails made from two DNA origami six-helix bundles. Twisting was controlled using ethidium bromide or SYBR Green I as model intercalators. Our findings demonstrate that DNA nanorails: (i) twist when subjected to intercalators and the amount of twisting is concentration dependent, and (ii) twisting saturates at elevated concentrations. This study provides insight into how complex DNA structures undergo conformational changes when exposed to intercalators and may be of relevance when exploring how intercalating drugs interact with condensed biological structures such as chromatin and chromosomes, as well as chromatin analogous gene expression devices.