bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace Iodide Dramatically Accelerates the Peroxidase Activity of VOx at ppb‐Concentration Levels
Authors: Niu Xiangheng , He Yanfang , Li Xin , Song Hongwei , Zhang Wenchi , Peng Yinxian , Pan Jianming , Qiu Fengxian
Published: December 2017

Despite artificial nanozymes, as compared to natural enzymes, exhibit distinct superiorities of low cost, robustness against harsh environments, high stability and easy mass‐production, the relatively lower activity and efficiency still seriously restrict their application in high‐performance photometric chemosensing and biosensing. Promoting the activity and efficiency of nanozymes turns to be a significant yet challenging goal of the nanozyme community. Here we found, for the first time, that trace I− can dramatically boost the peroxidase‐like activity (over 50‐fold higher) of VOx at ppb‐concentration levels. It was deduced that the significant enhancement of nanozymatic activity mainly results from the synergetic modulation of surface redox and electronic structure of VOx. Based on this finding, ultrasensitive photometric detection of both H2O2 and I− (down to nM) was realized.
Dynamic Recrystallization and Flow Behavior in Low Carbon Nb–Ti Microalloyed Steel
Authors: Yang Yong , Li Tian Rui , Jia Tao , Wang Zhao Dong , Misra Raja Devesh Kumar
Published: December 2017

Single‐pass hot compression tests are performed to study the hot deformation behavior of a low carbon microalloyed steel at temperatures in the range of 950–1050 °C and strain rate from 0.01 to 0.5 s–1. Based on true stress–strain data, the effect of strain rate and temperature on the flow behavior of this steel is analyzed and peak stress is determined as well. The partial derivative of the strain hardening rate to stress is used to determine the critical stress. The value of activation energy and the ratio of critical stress (strain) to peak stress (strain) are estimated. The relationship between characteristic points and Zener–Hollomon parameter is established. The kinetic model for the calculation of volume fraction of dynamic recrystallization is also established. The strain dependence of material constants are determined from fifth‐order polynomials and the flow stresses under different deformation conditions are predicted, consistent with the experimental results.
Oxocentered Units in Three Novel Rb‐Containing Copper Compounds Prepared by CVT Reaction Method
Authors: Kornyakov Ilya V. , Krivovichev Sergey V. , Gurzhiy Vladislav V.
Published: December 2017

Three novel copper compounds, Rb4Cu4OCl10 (I), Rb[Cu3O](SeO3)2Cl (II), and RbCu3(OH)(SeO3)Cl4(H2O)3 (III) were prepared by chemical vapor transport (CVT) reactions method from mixtures of CuO, SeO2, RbCl, and CuCl2. The crystal structures of the three compounds were determined by direct methods. Compound I is a Rb analogue of ponomarevite, K4Cu4OCl10. Its crystal structure contains {[OCu4]Cl10}4– clusters with oxocentered [OCu4]6+ tetrahedra as cores. The clusters are linked by the Rb+ cations. The crystal structure of II contains complex {[O2Cu6](SeO3)4Cl2}2– layers formed by dimers of edge‐sharing [OCu4]6+ tetrahedra interlinked via selenite groups and Cl– anions. The crystal structure of III is based upon {[(OH)Cu3](SeO3)}3+ layers formed by the [(OH)Cu3]5+ tetrahedra attached to (SeO3)2– groups. The layers are linked via Cl– anions and via hydrogen bonds to H2O molecules.
Sachs’ free data in real connection variables
Authors: De Paoli Elena , Speziale Simone
Published: December 2017

Abstract

We discuss the Hamiltonian dynamics of general relativity with real connection variables on a null foliation, and use the Newman-Penrose formalism to shed light on the geometric meaning of the various constraints. We identify the equivalent of Sachs’ constraint-free initial data as projections of connection components related to null rotations, i.e. the translational part of the ISO(2) group stabilising the internal null direction soldered to the hypersurface. A pair of second-class constraints reduces these connection components to the shear of a null geodesic congruence, thus establishing equivalence with the second-order formalism, which we show in details at the level of symplectic potentials. A special feature of the first-order formulation is that Sachs’ propagating equations for the shear, away from the initial hypersurface, are turned into tertiary constraints; their role is to preserve the relation between connection and shear under retarded time evolution. The conversion of wave-like propagating equations into constraints is possible thanks to an algebraic Bianchi identity; the same one that allows one to describe the radiative data at future null infinity in terms of a shear of a (non-geodesic) asymptotic null vector field in the physical spacetime. Finally, we compute the modification to the spin coefficients and the null congruence in the presence of torsion.
Chiral global embedding of fibre inflation models
Authors: Cicoli Michele , Ciupke David , Diaz Victor A. , Guidetti Veronica , Muia Francesco , Shukla Pramod
Published: December 2017

Abstract

We construct explicit examples of fibre inflation models which are globally embedded in type IIB orientifolds with chiral matter on D7-branes and full closed string moduli stabilisation. The minimal setup involves a Calabi-Yau threefold with h
1,1 = 4 Kähler moduli which features multiple K3 fibrations and a del Pezzo divisor supporting non-perturbative effects. We perform a consistent choice of orientifold involution, brane setup and gauge fluxes which leads to chiral matter and a moduli-dependent Fayet-Iliopoulos term. After D-term stabilisation, the number of Kähler moduli is effectively reduced to 3 and the internal volume reduces to the one of fibre inflation models. The inflationary potential is generated by suitable string loop corrections in combination with higher derivative effects. We analyse the inflationary dynamics both in the single-field approximation and by numerically deriving the full multi-field evolution in detail. Interestingly, we find that the Kähler cone conditions set strong constraints on the allowed inflaton field range.
High yield production of four-carbon dicarboxylic acids by metabolically engineered Escherichia coli
Authors: Martinez Irene , Gao Haijun , Bennett George N , San Ka-Yiu
Published: December 2017

Several metabolic engineered Escherichia coli strains were constructed and evaluated for four-carbon dicarboxylic acid production. Fumarase A, fumarase B and fumarase C single, double and triple mutants were constructed in a ldhA adhE mutant background overexpressing the pyruvate carboxylase from Lactococcus lactis. All the mutants produced succinate as the main four-carbon (C4) dicarboxylic acid product when glucose was used as carbon source with the exception of the fumAC and the triple fumB fumAC deletion strains, where malate was the main C4-product with a yield of 0.61–0.67 mol (mole glucose)−1. Additionally, a mdh mutant strain and a previously engineered high-succinate-producing strain (SBS550MG-Cms pHL413-Km) were investigated for aerobic malate production from succinate. These strains produced 40.38 mM (5.41 g/L) and 50.34 mM (6.75 g/L) malate with a molar yield of 0.53 and 0.55 mol (mole succinate)−1, respectively. Finally, by exploiting the high-succinate production capability, the strain SBS550MG-Cms243 pHL413-Km showed significant malate production in a two-stage process from glucose. This strain produced 133 mM (17.83 g/L) malate in 47 h, with a high yield of 1.3 mol (mole glucose)−1 and productivity of 0.38 g L−1 h−1.
Divergent tree growth response to recent climate warming ofAbies faxonianaat alpine treelines in east edge of Tibetan Plateau
Authors: Zhang Yuandong , Guo Mingming , Wang Xiaochun , Gu Fengxue , Liu Shirong
Published: December 2017

An anomalous reduction in tree growth indices has been detected in tree ring records from many circumpolar northern latitude sites in recent years, which was known as the divergence phenomenon. In order to understand whether the divergence phenomenon appeared at altitudinal treelines in east edge of Tibetan Plateau, we analyzed the correlation coefficients between tree growth and climate variables before and after recent climate warming, respectively. The results showed that divergence phenomenon took place and varied with sites. Compared with those in 1955–1982, the correlation coefficient of growth to mean temperature in June declined during 1983–2012. In Songpan site, more than half of the sampled trees showed an increasing positive correlation with temperature from July to September, while others turned to be a negative correlation. The positive responses to the mean temperature in previous‐year November and December declined in Markang site. Only in Miyaluo site, the positive correlation between tree ring index and temperature from July to September increased. Both the anomalous reduction or disappearance of the responses to the mean temperature and the divergent growth responses suggested that the divergence phenomenon was universal at altitudinal treelines in east edge of Tibetan Plateau, which had potentially significant influences on the estimation of forest productivity and climatic reconstructions based on tree ring.
A Brief Instrument to Assess Both Burnout and Professional Fulfillment in Physicians: Reliability and Validity, Including Correlation with Self-Reported Medical Errors, in a Sample of Resident and Practicing Physicians
Authors: Trockel Mickey , Bohman Bryan , Lesure Emi , Hamidi Maryam S. , Welle Dana , Roberts Laura , Shanafelt Tait
Published: December 2017

Objective

The objective of this study was to evaluate the performance of the Professional Fulfillment Index (PFI), a 16-item instrument to assess physicians’ professional fulfillment and burnout, designed for sensitivity to change attributable to interventions or other factors affecting physician well-being.

Methods

A sample of 250 physicians completed the PFI, a measure of self-reported medical errors, and previously validated measures including the Maslach Burnout Inventory (MBI), a one-item burnout measure, the World Health Organization’s abbreviated quality of life assessment (WHOQOL-BREF), and PROMIS short-form depression, anxiety, and sleep-related impairment scales. Between 2 and 3 weeks later, 227 (91%) repeated the PFI and the sleep-related impairment scale.

Results

Principal components analysis justified PFI subscales for professional fulfillment, work exhaustion, and interpersonal disengagement. Test-retest reliability estimates were 0.82 for professional fulfillment (α = 0.91), 0.80 for work exhaustion (α = 0.86), 0.71 for interpersonal disengagement (α = 0.92), and 0.80 for overall burnout (α = 0.92). PFI burnout measures correlated highly (r ≥ 0.50) with their closest related MBI equivalents. Cohen’s d effect size differences in self-reported medical errors for high versus low burnout classified using the PFI and the MBI were 0.55 and 0.44, respectively. PFI scales correlated in expected directions with sleep-related impairment, depression, anxiety, and WHOQOL-BREF scores. PFI scales demonstrated sufficient sensitivity to detect expected effects of a two-point (range 8–40) change in sleep-related impairment.

Conclusions

PFI scales have good performance characteristics including sensitivity to change and offer a novel contribution by assessing professional fulfillment in addition to burnout.
A study of Chinese medical students as dictionary users and potential users for an online medical termfinder
Authors: Ding Jun
Published: December 2017

This paper examines the dictionary use of Chinese medical students as ESP learners and their trial experience with the online Health Termfinder (HTF), a specialized dictionary tool for medical terms. Empirical data were collected first from a survey among a group of medical students at Fudan University on their previous dictionary-use behaviors and initial response to the introduction to the HTF and its bilingualization, and second from an assignment of using the bilingualized HTF for reading comprehension with the same group of students. The survey findings reveal that the medical students in general are aware of the importance of dictionaries in their ESP learning in spite of the alarming fact that the majority of them have not even used any English medical dictionaries (monolingual or bilingual). They are thus quite open to the idea of using an online termbank of specialized medical terms. But the HTF assignment findings also show that proper guidance and training is necessary for the termbank to be made actually useful for the lexical needs of Chinese ESP learners. It is also expected that the students’ feedback on their HTF experience, especially their demand for the termbank to include more cross-disciplinary medical terms, could be taken into consideration by the HTF builders.
Understanding the Role of Serotonin in Female Hypoactive Sexual Desire Disorder and Treatment Options
Authors: Croft Harry A.
Published: December 2017

Background

The neurobiology of sexual response is driven in part by dopamine and serotonin—the former modulating excitatory pathways and the latter regulating inhibitory pathways. Neurobiological underpinnings of hypoactive sexual desire disorder (HSDD) are seemingly related to overactive serotonin activity that results in underactive dopamine activity. As such, pharmacologic agents that decrease serotonin, increase dopamine, or some combination thereof, have therapeutic potential for HSDD.

Aim

To review the role of serotonin in female sexual function and the effects of pharmacologic interventions that target the serotonin system in the treatment of HSDD.

Methods

Searches of the Medline database for articles on serotonin and female sexual function.

Outcomes

Relevant articles from the peer-reviewed literature were included.

Results

Female sexual response is regulated not only by the sex hormones but also by several neurotransmitters. It is postulated that dopamine, norepinephrine, oxytocin, and melanocortins serve as key neuromodulators for the excitatory pathways, whereas serotonin, opioids, and endocannabinoids serve as key neuromodulators for the inhibitory pathways. Serotonin appears to be a key inhibitory modulator of sexual desire, because it decreases the ability of excitatory systems to be activated by sexual cues. Centrally acting drugs that modulate the excitatory and inhibitory pathways involved in sexual desire (eg, bremelanotide, bupropion, buspirone, flibanserin) have been investigated as treatment options for HSDD. However, only flibanserin, a multifunctional serotonin agonist and antagonist (5-hydroxytryptamine [5-HT]1A receptor agonist and 5-HT2A receptor antagonist), is currently approved for the treatment of HSDD.

Clinical Implications

The central serotonin system is 1 biochemical target for medications intended to treat HSDD.

Strengths and Limitations

This narrative review integrates findings from preclinical studies and clinical trials to elucidate neurobiological underpinnings of HSDD but is limited to 1 neurotransmitter system (serotonin).

Conclusion

Serotonin overactivity is a putative cause of sexual dysfunction in patients with HSDD. The unique pharmacologic profile of flibanserin tones down inhibitory serotonergic function and restores dopaminergic and noradrenergic function.
The Vulvar Pain Assessment Questionnaire: Factor Structure, Preliminary Norms, Internal Consistency, and Test-Retest Reliability
Authors: Dargie Emma , Holden Ronald R. , Pukall Caroline F.
Published: December 2017

Background

The Vulvar Pain Assessment Questionnaire (VPAQ) was developed to assist in the assessment and diagnosis of chronic vulvar pain (vulvodynia).

Aim

To further establish the psychometric properties of the VPAQ by examining factor structure, test-retest reliability, internal consistency, and scale normative data, and to gather feedback from those with vulvar pain about the usefulness and accessibility of the questionnaire.

Methods

182 participants completed a confidential online study and 70 participated again at time 2 (4 weeks later).

Outcomes

Participants were asked to complete the full VPAQ, which assesses pain characteristics, effects on various parts of their lives, coping strategies used, and romantic partner factors. Additional questions captured sociodemographics and feedback about the instrument.

Results

Exploratory structural equation modeling indicated that the previously established subscales, except the coping scale, had adequate model fit, and all items loaded significantly onto relevant factors. Pearson product moment correlations (r = 0.57–0.96) established strong 4-week test-retest reliability for most subscale scores, and Cronbach α indicated overall acceptable to high internal consistency (α = 0.56–0.95). Preliminary norms for the scales are supplied. Approximately half the participants reported an increase in their comfort level in discussing a range of topics after completing the VPAQ. Most participants reported that the length, readability, and range of VPAQ questions were “good” or “excellent.”

Clinical Implications

The results of this study provide further justification for using the VPAQ scales in clinical and research settings, preliminary norms for a vulvar pain population, and suggestions for interpretation.

Strengths and Limitations

This study established the psychometric properties of the VPAQ scales using multiple methods at 2 time points and gathered feedback from participants. However, data were collected online so diagnoses could not be confirmed and more than half the initial sample did not complete the survey at time 2.

Conclusion

The results of this study suggest that most VPAQ subscales (except the coping subscale) have moderate to strong psychometric properties and that the VPAQ is user friendly.
Testosterone Deficiency Causes Endothelial Dysfunction via Elevation of Asymmetric Dimethylarginine and Oxidative Stress in Castrated Rats
Authors: Kataoka Tomoya , Hotta Yuji , Maeda Yasuhiro , Kimura Kazunori
Published: December 2017

Background

Testosterone is believed to mediate the penile erectile response by producing adequate nitric oxide; therefore, testosterone deficiency results in erectile dysfunction through decreased nitric oxide bioavailability. However, the mechanisms underlying endothelial dysfunction in testosterone deficiency remain unclear.

Aim

To investigate the mechanism of endothelial dysfunction in a rat model of testosterone deficiency.

Methods

Rats were distributed into 3 groups: castrated (Cast), castrated and supplemented with testosterone (Cast + T), and sham (Sham). In the Cast + T group, castrated rats were treated daily with subcutaneous testosterone (3 mg/kg daily) for 4 weeks; Sham and Cast rats received only the vehicle.

Outcomes

Erectile function using intracavernosal pressure and mean arterial pressure measurements after electrical stimulation of the cavernous nerve, endothelial function using isometric tension, asymmetric dimethylarginine (ADMA) levels using ultra-performance liquid chromatography and tandem mass spectrometry, and inflammatory biomarker expression were performed 4 weeks after the operation.

Results

In the Cast group, the ratio of intracavernosal pressure to mean arterial pressure significantly decreased, acetylcholine-induced relaxation was lower, and serum ADMA, oxidative stress, and inflammation biomarker levels were significantly increased (P < .01). Testosterone injection significantly improved each of these parameters (P < .01).

Clinical Translation

The present results provide scientific evidence of the effect of testosterone deficiency on erectile function and the effect of testosterone replacement therapy.

Strengths and Limitations

This study provides evidence of the influence of testosterone deficiency on endothelial function by investigating ADMA and oxidative stress. A major limitation of this study is the lack of a direct link of increased ADMA by oxidative stress to inflammation.

Conclusion

Testosterone deficiency increased not only ADMA levels but also oxidative stress and inflammation in castrated rats, which can cause damage to the corpus cavernosum, resulting in erectile dysfunction.
Optimal heat transfer enhancement in plane Couette flow
Authors: Motoki Shingo , Kawahara Genta , Shimizu Masaki
Published: December 2017

Optimal heat transfer enhancement has been explored theoretically in plane Couette flow. The vector field (referred to as the ‘velocity’) to be optimised is time independent and divergence free, and temperature is determined in terms of the velocity as a solution to an advection-diffusion equation. The Prandtl number is set to unity, and consistent boundary conditions are imposed on the velocity and the temperature fields. The excess of a wall heat flux (or equivalently total scalar dissipation) over total energy dissipation is taken as an objective functional, and by using a variational method the Euler–Lagrange equations are derived, which are solved numerically to obtain the optimal states in the sense of maximisation of the functional. The laminar conductive field is an optimal state at low Reynolds number$Re\sim 10^{0}$. At higher Reynolds number$Re\sim 10^{1}$, however, the optimal state exhibits a streamwise-independent two-dimensional velocity field. The two-dimensional field consists of large-scale circulation rolls that play a role in heat transfer enhancement with respect to the conductive state as in thermal convection. A further increase of the Reynolds number leads to a three-dimensional optimal state at$Re\gtrsim 10^{2}$. In the three-dimensional velocity field there appear smaller-scale hierarchical quasi-streamwise vortex tubes near the walls in addition to the large-scale rolls. The streamwise vortices are tilted in the spanwise direction so that they may produce the anticyclonic vorticity antiparallel to the mean-shear vorticity, bringing about significant three-dimensionality. The isotherms wrapped around the tilted anticyclonic vortices undergo the cross-axial shear of the mean flow, so that the spacing of the wrapped isotherms is narrower and so the temperature gradient is steeper than those around a purely streamwise (two-dimensional) vortex tube, intensifying scalar dissipation and so a wall heat flux. Moreover, the tilted anticyclonic vortices induce the flow towards the wall to push low- (or high-) temperature fluids on the hot (or cold) wall, enhancing a wall heat flux. The optimised three-dimensional velocity fields achieve a much higher wall heat flux and much lower energy dissipation than those of plane Couette turbulence.
Combined 14C Analysis of Canvas and Organic Binder for Dating a Painting
Authors: Hendriks Laura , Hajdas Irka , Ferreira Ester S B , Scherrer Nadim C , Zumbühl Stefan , Küffner Markus , Wacker Lukas , Synal Hans-Arno , Günther Detlef
Published: December 2017

The use of accelerator mass spectrometry (AMS) for age determinations of paintings is growing due to decreasing sample size requirements. However, as only the support material is usually dated, the validity of the results may be questioned. This work describes a novel sampling and preparation technique for dating the natural organic binder using radiocarbon (14C) AMS. In the particular case of oil paintings, the natural oil used has a high probability of being representative of the time of creation, hereby circumventing the problem of the originality of the support material. A multi-technique approach was developed for a detailed characterization of all paint components to identify the binder type as well as pigments and additives present in the sample. The technique was showcased on a painting of the 20th century. The results by 14C AMS dating show that both the canvas and binding medium predate the signed date by 4–5 yr. This could be the time span for keeping painting material in the atelier. The method developed provides, especially given the low amounts of material needed for analysis, a superior precision and accuracy in dating and has potential to become a standard method for oil painting dating.
The calcium-dependent protein kinase 1 from Toxoplasma gondii as target for structure-based drug design
Authors: CARDEW EMILY M. , VERLINDE CHRISTOPHE L. M. J. , POHL EHMKE
Published: December 2017

The apicomplexan protozoan parasites include the causative agents of animal and human diseases ranging from malaria (Plasmodium spp.) to toxoplasmosis (Toxoplasma gondii). The complex life cycle of T. gondii is regulated by a unique family of calcium-dependent protein kinases (CDPKs) that have become the target of intensive efforts to develop new therapeutics. In this review, we will summarize structure-based strategies, recent successes and future directions in the pursuit of specific and selective inhibitors of T. gondii CDPK1.
Resveratrol and inflammatory bowel disease: the evidence so far
Authors: Nunes Sandra , Danesi Francesca , Del Rio Daniele , Silva Paula
Published: December 2017

Despite the fact that inflammatory bowel disease (IBD) has still no recognised therapy, treatments which have proven at least mildly successful in improving IBD symptoms include anti-inflammatory drugs and monoclonal antibodies targeting pro-inflammatory cytokines. Resveratrol, a natural (poly)phenol found in grapes, red wine, grape juice and several species of berries, has been shown to prevent and ameliorate intestinal inflammation. Here, we discuss the role of resveratrol in the improvement of inflammatory disorders involving the intestinal mucosa. The present review covers three specific aspects of resveratrol in the framework of inflammation: (i) its content in food; (ii) its intestinal absorption and metabolism; and (iii) its anti-inflammatory effects in the intestinal mucosain vitroand in the very fewin vivostudies present to date. Actually, if several studies have shown that resveratrol may down-regulate mediators of intestinal immunity in rodent models, only two groups have performed intervention studies in human subjects using resveratrol as an agent to improve IBD conditions. The effects of resveratrol should be further investigated by conducting well-designed clinical trials, also taking into account different formulations for the delivery of the bioactive compound.
Characteristics of Medical Teams in Disaster
Authors: Redmond Anthony D.
Published: December 2017

RedmondAD. Characteristics of medical teams in disaster. Prehosp Disaster Med. 2017:32(6):700.
Treating complex depression with cognitive behavioural therapy
Authors: Barton Stephen , Armstrong Peter , Wicks Louise , Freeman Elizabeth , Meyer Thomas D.
Published: December 2017

Cognitive behavioural therapy (CBT) for major depression is an effective treatment, but outcomes for complex cases, with co-occurring biological, psychological and social factors, are variable. Complexity factors can cause treatment to become diffuse, disorganized and over-complicated. At Step 3, disorder-specific protocols should be provided with therapy kept as simple as possible and delivered responsively, e.g. barriers to treatment should be tackled, ensure the client is well-prepared and seek to form a strong therapeutic alliance. At Step 4, if disorder-specific protocols have been ineffective, the priority is to formulate how complexity factors are interacting with the client's depression. An individualized formulation is used to carefully target these interactions. The treatment is still evidence-based and simple at the point of delivery, but there is greater emphasis on case-level interactions that are unique to each individual. Case examples are used to illustrate both approaches.
Rare symbionts may contribute to the resilience of coral–algal assemblages
Authors: Ziegler Maren , Eguíluz Víctor M , Duarte Carlos M , Voolstra Christian R
Published: December 2017

The association between corals and photosynthetic dinoflagellates (Symbiodinium spp.) is the key to the success of reef ecosystems in highly oligotrophic environments, but it is also their Achilles‘ heel due to its vulnerability to local stressors and the effects of climate change. Research during the last two decades has shaped a view that coral host–Symbiodinium pairings are diverse, but largely exclusive. Deep sequencing has now revealed the existence of a rare diversity of cryptic Symbiodinium assemblages within the coral holobiont, in addition to one or a few abundant algal members. While the contribution of the most abundant resident Symbiodinium species to coral physiology is widely recognized, the significance of the rare and low abundant background Symbiodinium remains a matter of debate. In this study, we assessed how coral–Symbiodinium communities assemble and how rare and abundant components together constitute the Symbiodinium community by analyzing 892 coral samples comprising >110 000 unique Symbiodinium ITS2 marker gene sequences. Using network modeling, we show that host–Symbiodinium communities assemble in non-random ‘clusters‘ of abundant and rare symbionts. Symbiodinium community structure follows the same principles as bacterial communities, for which the functional significance of rare members (the ‘rare bacterial biosphere’) has long been recognized. Importantly, the inclusion of rare Symbiodinium taxa in robustness analyses revealed a significant contribution to the stability of the host–symbiont community overall. As such, it highlights the potential functions rare symbionts may provide to environmental resilience of the coral holobiont.
Microbial life on a sand grain: from bulk sediment to single grains
Authors: Probandt David , Eickhorst Thilo , Ellrott Andreas , Amann Rudolf , Knittel Katrin
Published: December 2017

Globally, marine surface sediments constitute a habitat for estimated 1.7 × 1028 prokaryotes. For benthic microbial community analysis, usually, several grams of sediment are processed. In this study, we made the step from bulk sediments to single sand grains to address the microbial community directly in its micro-habitat: the individual bacterial diversity on 17 sand grains was analyzed by 16S ribosomal RNA gene sequencing and visualized on sand grains using catalyzed reporter deposition fluorescence in situ hybridization. In all, 104–105 cells were present on grains from 202 to 635 µm diameter. Colonization was patchy, with exposed areas largely devoid of any epi-growth (mean cell–cell distance 4.5±5.9 µm) and protected areas more densely populated (0.5±0.7 µm). Mean cell–cell distances were 100-fold shorter compared with the water column. In general, growth occurred in monolayers. Each sand grain harbors a highly diverse bacterial community as shown by several thousand species-level operational taxonomic units (OTU)0.97. Only 4–8 single grains are needed to cover 50% of OTU0.97 richness found in bulk sediment. Although bacterial communities differed between sand grains, a core community accounting for >50% of all cells was present on each sand grain. The communities between sediment grains are more similar than between soil macroaggregates.
On the impact of capillarity for strength at the nanoscale
Authors: Mameka Nadiia , Markmann Jürgen , Weissmüller Jörg
Published: December 2017

The interior of nanoscale crystals experiences stress that compensates for the capillary forces and that can be large, in the order of 1 GPa. Various studies have speculated on whether and how this surface-induced stress affects the stability and plasticity of small crystals. Yet, experiments have so far failed to discriminate between the surface contribution and other, bulk-related size effects. To clarify the issue, here we study the variation of the flow stress of a nanomaterial while distinctly different variations of the two capillary parameters, surface tension, and surface stress, are imposed under control of an applied electric potential. Our theory qualifies the suggested impact of surface stress as not forceful and instead predicts a significant contribution of the surface energy, as measured by the surface tension. The predictions for the combined potential-dependence and size-dependence of the flow stress are quantitatively supported by the experiment. Previous suggestions, favoring the surface stress as the relevant capillary parameter, are not consistent with our experiment.
Evidence for a topological excitonic insulator in InAs/GaSb bilayers
Authors: Du Lingjie , Li Xinwei , Lou Wenkai , Sullivan Gerard , Chang Kai , Kono Junichiro , Du Rui-Rui
Published: December 2017

Electron–hole pairing can occur in a dilute semimetal, transforming the system into an excitonic insulator state in which a gap spontaneously appears at the Fermi surface, analogous to a Bardeen–Cooper–Schrieffer (BCS) superconductor. Here, we report optical spectroscopic and electronic transport evidence for the formation of an excitonic insulator gap in an inverted InAs/GaSb quantum-well system at low temperatures and low electron–hole densities. Terahertz transmission spectra exhibit two absorption lines that are quantitatively consistent with predictions from the pair-breaking excitation dispersion calculated based on the BCS gap equation. Low-temperature electronic transport measurements reveal a gap of ~2 meV (or ~25 K) with a critical temperature of ~10 K in the bulk, together with quantized edge conductance, suggesting the occurrence of a topological excitonic insulator phase.
Characterization of a membrane-bound C-glucosyltransferase responsible for carminic acid biosynthesis in Dactylopius coccus Costa
Authors: Kannangara Rubini , Siukstaite Lina , Borch-Jensen Jonas , Madsen Bjørn , Kongstad Kenneth T. , Staerk Dan , Bennedsen Mads , Okkels Finn T. , Rasmussen Silas A. , Larsen Thomas O. , Frandsen Rasmus J. N. , Møller Birger Lindberg
Published: December 2017

Carminic acid, a glucosylated anthraquinone found in scale insects likeDactylopius coccus, has since ancient times been used as a red colorant in various applications. Here we show that a membrane-bound C-glucosyltransferase, isolated fromD.coccusand designated DcUGT2, catalyzes the glucosylation of flavokermesic acid and kermesic acid into their respective C-glucosides dcII and carminic acid. DcUGT2 is predicted to be a type I integral endoplasmic reticulum (ER) membrane protein, containing a cleavable N-terminal signal peptide and a C-terminal transmembrane helix that anchors the protein to the ER, followed by a short cytoplasmic tail. DcUGT2 is found to be heavily glycosylated. Truncated DcUGT2 proteins synthesized in yeast indicate the presence of an internal ER-targeting signal. The cleavable N-terminal signal peptide is shown to be essential for the activity of DcUGT2, whereas the transmembrane helix/cytoplasmic domains, although important, are not crucial for its catalytic function.
The end-joining factor Ku acts in the end-resection of double strand break-free arrested replication forks
Authors: Teixeira-Silva Ana , Ait Saada Anissia , Hardy Julien , Iraqui Ismail , Nocente Marina Charlotte , Fréon Karine , Lambert Sarah A. E.
Published: December 2017

Replication requires homologous recombination (HR) to stabilize and restart terminally arrested forks. HR-mediated fork processing requires single stranded DNA (ssDNA) gaps and not necessarily double strand breaks. We used genetic and molecular assays to investigate fork-resection and restart at dysfunctional, unbroken forks in Schizosaccharomyces pombe. Here, we report that fork-resection is a two-step process regulated by the non-homologous end joining factor Ku. An initial resection mediated by MRN-Ctp1 removes Ku from terminally arrested forks, generating ~110 bp sized gaps obligatory for subsequent Exo1-mediated long-range resection and replication restart. The mere lack of Ku impacts the processing of arrested forks, leading to an extensive resection, a reduced recruitment of RPA and Rad51 and a slower fork-restart process. We propose that terminally arrested forks undergo fork reversal, providing a single DNA end for Ku binding. We uncover a role for Ku in regulating end-resection of unbroken forks and in fine-tuning HR-mediated replication restart.
Observation of superparamagnetism in coexistence with quantum anomalous Hall C = ±1 and C = 0 Chern states
Authors: Lachman Ella O. , Mogi Masataka , Sarkar Jayanta , Uri Aviram , Bagani Kousik , Anahory Yonathan , Myasoedov Yuri , Huber Martin E. , Tsukazaki Atsushi , Kawasaki Masashi , Tokura Yoshinori , Zeldov Eli
Published: December 2017

Simultaneous transport and scanning nanoSQUID-on-tip magnetic imaging studies in Cr-(Bi,Sb)2Te3 modulation-doped films reveal the presence of superparamagnetic order within the quantum anomalous Hall regime. In contrast to the expectation that a long-range ferromagnetic order is required for establishing the quantum anomalous Hall state, superparamagnetic dynamics of weakly interacting nanoscale magnetic islands is observed both in the plateau transition regions, as well as within the fully quantized C = ±1 Chern plateaus. Modulation doping of the topological insulator films is found to give rise to significantly larger superparamagnetic islands as compared to uniform magnetic doping, evidently leading to enhanced robustness of the quantum anomalous Hall effect. Nonetheless, even in this more robust quantum state, attaining full quantization of transport coefficients requires magnetic alignment of at least 95% of the superparamagnetic islands. The superparamagnetic order is also found within the incipient C = 0 zero Hall plateau, which may host an axion state if the top and bottom magnetic layers are magnetized in opposite directions. In this regime, however, a significantly lower level of island alignment is found in our samples, hindering the formation of the axion state. Comprehension and control of superparamagnetic dynamics is thus a key factor in apprehending the fragility of the quantum anomalous Hall state and in enhancing the endurance of the different quantized states to higher temperatures for utilization of robust topological protection in novel devices.
The evolution of the macrophage-specific enhancer (Fms intronic regulatory element) within the CSF1R locus of vertebrates
Authors: Hume David A. , Wollscheid-Lengeling Evi , Rojo Rocio , Pridans Clare
Published: December 2017

The Csf1r locus encodes the receptor for macrophage colony-stimulating factor, which controls the proliferation, differentiation and survival of macrophages. The 300 bp Fms intronic regulatory element (FIRE), within the second intron of Csf1r, is necessary and sufficient to direct macrophage-specific transcription. We have analysed the conservation and divergence of the FIRE DNA sequence in vertebrates. FIRE is present in the same location in the Csf1r locus in reptile, avian and mammalian genomes. Nearest neighbor analysis based upon this element alone largely recapitulates phylogenies inferred from much larger genomic sequence datasets. One core element, containing binding sites for AP1 family and the macrophage-specific transcription factor, PU.1, is conserved from lizards to humans. Around this element, the FIRE sequence is conserved within clades with the most conserved elements containing motifs for known myeloid-expressed transcription factors. Conversely, there is little alignment between clades outside the AP1/PU.1 element. The analysis favours a hybrid between “enhanceosome” and “smorgasbord” models of enhancer function, in which elements cooperate to bind components of the available transcription factor milieu.
MicroRNA-like RNAs from the same miRNA precursors play a role in cassava chilling responses
Authors: Zeng Changying , Xia Jing , Chen Xin , Zhou Yufei , Peng Ming , Zhang Weixiong
Published: December 2017

MicroRNAs (miRNAs) are known to play important roles in various cellular processes and stress responses. MiRNAs can be identified by analyzing reads from high-throughput deep sequencing. The reads realigned to miRNA precursors besides canonical miRNAs were initially considered as sequencing noise and ignored from further analysis. Here we reported a small-RNA species of phased and half-phased miRNA-like RNAs different from canonical miRNAs from cassava miRNA precursors detected under four distinct chilling conditions. They can form abundant multiple small RNAs arranged along precursors in a tandem and phased or half-phased fashion. Some of these miRNA-like RNAs were experimentally confirmed by re-amplification and re-sequencing, and have a similar qRT-PCR detection ratio as their cognate canonical miRNAs. The target genes of those phased and half-phased miRNA-like RNAs function in process of cell growth metabolism and play roles in protein kinase. Half-phased miR171d.3 was confirmed to have cleavage activities on its target gene P-glycoprotein 11, a broad substrate efflux pump across cellular membranes, which is thought to provide protection for tropical cassava during sharp temperature decease. Our results showed that the RNAs from miRNA precursors are miRNA-like small RNAs that are viable negative gene regulators and may have potential functions in cassava chilling responses.
Active-site plasticity revealed in the asymmetric dimer of AnPrx6 the 1-Cys peroxiredoxin and molecular chaperone from Anabaena sp. PCC 7120
Authors: Mishra Yogesh , Hall Michael , Locmelis Roland , Nam Kwangho , Söderberg Christopher A. G. , Storm Patrik , Chaurasia Neha , Rai Lal Chand , Jansson Stefan , Schröder Wolfgang P. , Sauer Uwe H.
Published: December 2017

Peroxiredoxins (Prxs) are vital regulators of intracellular reactive oxygen species levels in all living organisms. Their activity depends on one or two catalytically active cysteine residues, the peroxidatic Cys (CP) and, if present, the resolving Cys (CR). A detailed catalytic cycle has been derived for typical 2-Cys Prxs, however, little is known about the catalytic cycle of 1-Cys Prxs. We have characterized Prx6 from the cyanobacteriumAnabaenasp. strain PCC7120 (AnPrx6) and found that in addition to the expected peroxidase activity, AnPrx6 can act as a molecular chaperone in its dimeric state, contrary to other Prxs. The AnPrx6 crystal structure at 2.3 Å resolution reveals different active site conformations in each monomer of the asymmetric obligate homo-dimer. Molecular dynamic simulations support the observed structural plasticity. A FSH motif, conserved in 1-Cys Prxs, precedes the active site PxxxTxxCp signature and might contribute to the 1-Cys Prx reaction cycle.
Pre-treatment inflammatory indexes as predictors of survival and cetuximab efficacy in metastatic colorectal cancer patients with wild-type RAS
Authors: Yang Jing , Guo Xinli , Wang Manni , Ma Xuelei , Ye Xiaoyang , Lin Panpan
Published: December 2017

This study aims at evaluating the prognostic significance of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic immune-inflammation indexes (SII) in metastatic colorectal cancer (mCRC) patients treated with cetuximab. Ninety-five patients receiving cetuximab for mCRC were categorized into the high or low NLR, PLR, LMR, and SII groups based on their median index values. Univariate and multivariate survival analysis were performed to identify the indexes’ correlation with progression-free survival (PFS) and overall survival (OS). In the univariate analysis, ECOG performance status, neutrphil counts, lymphocyte counts, monocyte counts, NLR, PLR, and LDH were associated with survival. Multivariate analysis showed that ECOG performance status of 0 (hazard ratio [HR] 3.608, p < 0.001; HR 5.030, p < 0.001, respectively), high absolute neutrophil counts (HR 2.837, p < 0.001; HR 1.922, p = 0.026, respectively), low lymphocyte counts (HR 0.352, p < 0.001; HR 0.440, p = 0.001, respectively), elevated NLR (HR 3.837, p < 0.001; HR 2.467, p = 0.006) were independent predictors of shorter PFS and OS. In conclusion, pre-treatment inflammatory indexes, especially NLR were potential biomarkers to predict the survival of mCRC patients with cetuximab therapy.
Proteomics and antivenomics of Echis carinatus carinatus venom: Correlation with pharmacological properties and pathophysiology of envenomation
Authors: Patra Aparup , Kalita Bhargab , Chanda Abhishek , Mukherjee Ashis K.
Published: December 2017

The proteome composition of Echis carinatus carinatus venom (ECV) from India was studied for the first time by tandem mass spectrometry analysis. A total of 90, 47, and 22 distinct enzymatic and non-enzymatic proteins belonging to 15, 10, and 6 snake venom protein families were identified in ECV by searching the ESI-LC-MS/MS data against non-redundant protein databases of Viperidae (taxid 8689), Echis (taxid 8699) and Echis carinatus (taxid 40353), respectively. However, analysis of MS/MS data against the Transcriptome Shotgun Assembly sequences (87 entries) of conger E. coloratus identified only 14 proteins in ECV. Snake venom metalloproteases and snaclecs, the most abundant enzymatic and non-enzymatic proteins, respectively in ECV account for defibrinogenation and the strong in vitro pro-coagulant activity. Further, glutaminyl cyclase, aspartic protease, aminopeptidase, phospholipase B, vascular endothelial growth factor, and nerve growth factor were reported for the first time in ECV. The proteome composition of ECV was well correlated with its biochemical and pharmacological properties and clinical manifestations observed in Echis envenomed patients. Neutralization of enzymes and pharmacological properties of ECV, and immuno-cross-reactivity studies unequivocally point to the poor recognition of <20 kDa ECV proteins, such as PLA2, subunits of snaclec, and disintegrin by commercial polyvalent antivenom.
Semantic discrimination impacts tDCS modulation of verb processing
Authors: Niccolai Valentina , Klepp Anne , Indefrey Peter , Schnitzler Alfons , Biermann-Ruben Katja
Published: December 2017

Motor cortex activation observed during body-related verb processing hints at simulation accompanying linguistic understanding. By exploiting the up- and down-regulation that anodal and cathodal transcranial direct current stimulation (tDCS) exert on motor cortical excitability, we aimed at further characterizing the functional contribution of the motor system to linguistic processing. In a double-blind sham-controlled within-subjects design, online stimulation was applied to the left hemispheric hand-related motor cortex of 20 healthy subjects. A dual, double-dissociation task required participants to semantically discriminate concrete (hand/foot) from abstract verb primes as well as to respond with the hand or with the foot to verb-unrelated geometric targets. Analyses were conducted with linear mixed models. Semantic priming was confirmed by faster and more accurate reactions when the response effector was congruent with the verb’s body part. Cathodal stimulation induced faster responses for hand verb primes thus indicating a somatotopical distribution of cortical activation as induced by body-related verbs. Importantly, this effect depended on performance in semantic discrimination. The current results point to verb processing being selectively modifiable by neuromodulation and at the same time to a dependence of tDCS effects on enhanced simulation. We discuss putative mechanisms operating in this reciprocal dependence of neuromodulation and motor resonance.