bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of raw materials and self‐organized Bi2O3–Ag eutectic by X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy
Authors: Szubka Magdalena , Talik Ewa , Sadecka Katarzyna , Pawlak Dorota Anna , Zajdel Pawel , Guzik Adam
Published: June 2017

Bi2O3–Ag raw materials were prepared using different synthetic routes: mortar and pestle and ball‐milling. They were later used as starting materials for the micro‐pulling down method. After the micro‐pulling down, the Bi2O3–Ag composites were annealed under vacuum, H2 and air atmospheres. All samples were characterized by the following methods: X‐ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and X‐ray photoelectron spectroscopy (XPS). The SEM/EDS and XPS analyses showed that the raw materials prepared by ball‐milling had a much more homogenous distribution of silver. XPS investigations of all Bi2O3–Ag composites showed that Bi ions are mainly in the 3+ oxidation state but additionally some may exist in the Bi0 (metallic) and defected Bi(3‐x)+ valence states. In the case of Bi2O3–Ag composites grown from ball‐milled raw materials and annealed in H2, XPS studies clearly showed the presence of metallic silver nanoparticles, Ag0. Besides the nanoparticles, bulk metallic silver Ag0 and two oxidation states for silver Ag2O and AgO for all examined eutectic were found. The estimated band gap, based on XPS was about 2.8 eV. In the case of samples obtained from ball‐milled raw materials, additional states near the Fermi level were found which could be related to partial transformation of Bi2O3 into Bi0.
Anionic Extraction for Efficient Recovery of Biobased 2,3‐Butanediol—A Platform for Bulk and Fine Chemicals
Authors: Drabo Peter , Tiso Till , Heyman Benedikt , Sarikaya Eda , Gaspar Paula , Förster Jochen , Büchs Jochen , Blank Lars Mathias , Delidovich Irina
Published: June 2017

2,3‐Butanediol (BDO) presents a promising platform molecule for the synthesis of basic and fine chemicals. Biotechnological production of BDO from renewable resources with living microbes enables high concentrations in the fermentation broth. The recovery of high‐boiling BDO from an aqueous fermentation broth presents a subsequent challenge. A method is proposed for BDO isolation based on reversible complexation with phenylboronate in an anionic complex. BDO can be recovered by back‐extraction into an acidic solution. The composition of the extracted species was determined by NMR spectroscopy, MS, and GC–MS methods. The conditions of extraction and back‐extraction were optimized by using commercial BDO and finally applied to different fermentation broths. Up to 72–93 % BDO can be extracted and up to 80–90 % can be back‐extracted under the optimized conditions. Purified bio‐BDO was used in the presence of sulfuric acid for the synthesis of methyl ethyl ketone, an established organic solvent and discussed tailor‐made biofuel.
Two‐stage metabolism inferred from diel oxygen dynamics in aquatic ecosystems
Authors: Schindler Daniel E. , Jankowski KathiJo , A'mar Z. Teresa , Holtgrieve Gordon W.
Published: June 2017

Dynamics of dissolved oxygen in aquatic ecosystems reflect the biological, physical, and chemical processes that regulate ecosystem metabolism. Organic matter that supports ecosystem respiration (ER) is produced both by in situ photosynthesis and via loading from terrestrial ecosystems. Terrestrial‐derived organic matter is relatively recalcitrant and its availability is stable at diel time scales relative to substrates produced through photosynthesis, which are more labile and often show distinct diel changes in availability. Here, we explored whether the contributions of these two sources of organic matter to ecosystem metabolism could be quantified by a process model of photosynthesis and ER fit to high‐frequency observations of oxygen concentration in streams. We found that a two‐stage model of respiration provided a better fit to diel oxygen dynamics in most streams than a model assuming that the substrates supporting ER were one temporally stable pool. Two‐stage models estimated peak daytime respiration rates that were ~2.9× higher on average than nighttime rates, but this increase was variable and ranged from 1.1 to 11.6×. Estimates of gross primary production were 1.35× higher, on average, (range = 1.04–7.91×) compared to estimates generated by a single‐stage model. Streams draining watersheds with less than about 7% gradient exhibited oxygen dynamics that provided comparable statistical support for single‐stage metabolism, likely due to the higher loading of allochthonous organic matter that swamped metabolism based on autochthonous production in these streams. Ecosystem metabolism in streams draining steeper watersheds was best characterized by two‐stage metabolism, reflecting the greater importance of autochthonous contributions to labile organic carbon pools in these ecosystems.
Dynamic Kinetic Resolution of Ethyl 1,2,3,4‐Tetrahydro‐β‐carboline‐1‐carboxylate: Use of Different Hydrolases for Stereocomplementary Processes
Authors: Megyesi Rita , Mándi Attila , Kurtán Tibor , Forró Enikő , Fülöp Ferenc
Published: June 2017

Both enantiomers of 1,2,3,4‐tetrahydro‐β‐carboline‐1‐carboxylic acid have been prepared by dynamic kinetic resolution of the corresponding ethyl ester (±)‐1. CAL‐B‐catalysed hydrolysis of (±)‐1·HCl in NH4OAc buffer (pH 8.0, 30 °C) provided amino acid (R)‐2·HCl with 98 % ee and 90 % yield in 20 min. The hydrolysis with Alcalase in borate buffer (pH 8.0, 30 °C) showed S selectivity and the product (S)‐2·HCl was obtained with 60 % ee and 66 % yield in 45 h. The absolute configuration of (S)‐2 was determined by TDDFT electronic circular dichroism and optical rotation calculations.
Recent Applications of Rh‐ and Pd‐Catalyzed C(sp3)–H Functionalization in Natural Product Total Synthesis
Authors: Brady Patrick B. , Bhat Vikram
Published: June 2017

The advent of C(sp3)–H functionalization has heralded a paradigm shift in natural product synthesis. Indeed, several reports in which C–H functionalization serves as the key step in the synthesis have appeared over the years. The purpose of this Microreview is briefly to summarize total syntheses reported during 2014–2016 with emphasis on the most innovative results relating to C–H functionalization. In addition, new advances in the field of Rh‐ and Pd‐catalyzed C(sp3)–H functionalization are discussed with the aim of providing readers with new disconnection ideas for their total synthesis endeavors.
Thermal Properties and Reliability of a Lauric Acid/Nonanoic Acid Binary Mixture as a Phase‐Change Material for Thermal Energy Storage
Authors: Wang Zhao , Sun Jinhe , Xie Shaolei , Ma Guixiang , Jia Yongzhong
Published: June 2017

The thermal properties of a binary system composed of lauric acid (LA) and nonanoic acid (NA) and its binary phase diagram were studied. To put this binary system into practice, the mixture containing 96 wt % of LA was selected, which has a phase‐change temperature of 41 °C and a latent heat of 163 J g−1, which is suitable for a domestic water heating application. Additionally, its thermal and chemical structure stability, thermal conductivity, degree of supercooling, and thermal reliability were investigated by using thermogravimetric analysis, FTIR spectroscopy, thermal conductivity analysis, the T‐history method, and an accelerated thermal cycle test for 1000 melt/freeze cycles, respectively. The results of these tests indicated that the mixture has a remarkable thermal stability, a good chemical structure stability, no supercooling, and an excellent thermal reliability. Therefore, the mixture can be a potential phase‐change material for thermal energy storage.
Integrating geographically isolated wetlands into land management decisions
Authors: Golden Heather E , Creed Irena F , Ali Genevieve , Basu Nandita B , Neff Brian P , Rains Mark C , McLaughlin Daniel L , Alexander Laurie C , Ameli Ali A , Christensen Jay R , Evenson Grey R , Jones Charles N , Lane Charles R , Lang Megan
Published: June 2017

Wetlands across the globe provide extensive ecosystem services. However, many wetlands – especially those surrounded by uplands, often referred to as geographically isolated wetlands (GIWs) – remain poorly protected. Protection and restoration of wetlands frequently requires information on their hydrologic connectivity to other surface waters, and their cumulative watershed‐scale effects. The integration of measurements and models can supply this information. However, the types of measurements and models that should be integrated are dependent on management questions and information compatibility. We summarize the importance of GIWs in watersheds and discuss what wetland connectivity means in both science and management contexts. We then describe the latest tools available to quantify GIW connectivity and explore crucial next steps to enhancing and integrating such tools. These advancements will ensure that appropriate tools are used in GIW decision making and maintaining the important ecosystem services that these wetlands support.
Geochronology, geochemistry, and tectonic implications of Jishou Cretaceous diabase, western Xuefengshan tectonic zone in South China
Authors: Su Jinbao , Dong Shuwen , Zhang Yueqiao , Ma Licheng , Chen Xuanhua
Published: June 2017

From the east of the Xuefengshan tectonic zone (XTZ) to the Pacific coast of the South China Block, there exist widespread Mesozoic magmatic rocks, which attract a great deal of attention for their forming mechanism and evolutional history. Among them, the Mesozoic Jishou diabase located at the west of the XTZ is reported in this study. Based on our geochronologic analysis, the diabase has a U–Pb age of 134 ± 2.3 Ma. The diabase belongs to calc‐alkaline series in a SiO2‐K2O diagram and illustrates significant enrichment in light rare earth elements and flat heavy rare earth elements without obvious Eu anomalies. Meanwhile, the diabase has negative εHf(t) and εNd(t) values and higher radiogenic 87Sr/86Sr(t) ratios, suggestive of EM2‐like Sr‐Nd isotopic compositions. The diabase shows high variations in 207Pb/204Pb(t; 15.609–15.671), 206Pb/204Pb(t; 17.943–18.742), and 208Pb/204Pb(t; 38.268–39.302). It is suggested that the Jishou diabase may be generated from the lithospheric mantle in response to the decompression melting accompanied by lithospheric extension during Pacific subduction process. During the Early Cretaceous (145–120 Ma), the upwelling and melting of the mantle occurred under the XTZ, causing intraplate Jishou diabase magma. Subsequently, the significantly descending of the subducted Paleo‐Pacific slab led progressively eastward generation and migration of subduction‐related magmas, resulting in a widespread distribution of igneous rocks in the Cathaysia Block.
The effect of adhesives on inflammatory immune‐markers during renal injury healing
Authors: Lloris‐Carsí José Miguel , Barrios Carlos , Prieto‐Moure Beatriz , Lloris‐Cejalvo José Miguel , Cejalvo‐Lapeña Dolores
Published: June 2017

Renal injury is common in abdominal trauma. Adhesives and sealants can be used to repair and preserve damaged organs. We describe the effect of three biomaterial treatments (TachoSil, GelitaSpon, and Adhflex) on injured renal tissue. Renal traumatic injuries were experimentally induced in male Wistar rats (n = 90) using a punch. Animals were divided into five groups: (1) sham noninjured (n = 3) and punch injury groups; (2) nontreated (n = 6); (3) TachoSil (n = 27); (4) GelitaSpon (n = 27); and (5) Adhflex (n = 27). Wound healing was evaluated 2, 6, and 18 days postinjury by inflammatory cytokines response, histopathological evolution of lesions, inflammatory reaction markers (CD68), and vascular neoformation (CD31). The TachoSil group showed the least inflammatory reaction among the three treated groups, which showed similarly low inflammatory reaction 18 days postinjury. Ciliary neurotrophic factor, soluble intercellular adhesion molecule‐1, L‐selectin, thymus chemokine, and TIMP metallopeptidase inhibitor 1 expression peaked between 2 and 6 days postinjury. TachoSil promoted the highest cytokine expression. The Adhflex group had the highest CD31 inflammatory immune‐marker levels at 2 and 6 days postinjury, but there was a similar decrease in CD31 levels in all three groups at 18 days postinjury. The results show that all three sealant treatments induced a normal healing process with the typical pattern of proinflammatory cytokine and immune‐marker expression. Each tested sealant substance could be suitable treatment for renal lacerations. The findings of this study indicate that Adhflex® elastic cyanoacrylate does not induce an adverse inflammatory reaction, and therefore, could be considered as one of the first‐line treatments for renal injuries. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1444–1455, 2018.
Immediate Initiation of Antiretroviral Therapy for HIV Infection Accelerates Bone Loss Relative to Deferring Therapy: Findings from the START Bone Mineral Density Substudy, a Randomized Trial
Authors: Hoy Jennifer F , Grund Birgit , Roediger Mollie , Schwartz Ann V , Shepherd John , Avihingsanon Anchalee , Badal-Faesen Sharlaa , de Wit Stephane , Jacoby Simone , La Rosa Alberto , Pujari Sanjay , Schechter Mauro , White David , Engen Nicole Wyman , Ensrud Kristine , Aagaard Peer D , Carr Andrew ,   for the INSIGHT START Bone Mineral Density Substudy Group
Published: June 2017

Both HIV infection and antiretroviral therapy (ART) are associated with lower bone mineral density (BMD) and increased fracture risk. Because the relative contributions of ART and untreated HIV to BMD loss are unclear, it is important to quantify the effect of ART on bone. We compared the effect of early ART initiation (CD4 >500 cells/μL) with deferred ART on change in BMD in the START Bone Mineral Density substudy, a randomized trial evaluating the effect of immediate ART initiation versus deferring ART (to CD4 <350 cells/μL). BMD was measured annually at the lumbar spine and hip by dual-energy X-ray absorptiometry (DXA). Percent change in BMD by treatment assignment (intent-to-treat analysis) was estimated using longitudinal mixed models and linear regression. Baseline and follow-up DXA scans were available for 399 (195 immediate, 204 deferred) participants (median age 32 years, 80% non-white, 26% women, median CD4 count 642 cells/μL). ART (most commonly including tenofovir and efavirenz) was used for 95% and 18% of follow-up in the immediate and deferred ART groups, respectively. Through 2.2 years mean follow-up, immediate ART resulted in greater BMD declines than deferred ART at the hip (–2.5% versus –1.0%; difference –1.5%, 95% confidence interval [CI] –2.2 to –0.8, p < 0.001) and spine (–1.9% versus –0.4%; difference –1.6%, 95% CI –2.2 to –1.0, p < 0.001). BMD declines were greatest in the first year of ART. In the immediate ART group, spine BMD stabilized after year 1, whereas hip BMD declined progressively over 2 years. After year 1, BMD changes were similar in the immediate and deferred groups. No clinical, HIV-related, or ART characteristic predicted greater BMD loss in either group. All HIV treatment guidelines now recommend ART initiation at HIV diagnosis because of the reduced risk of serious clinical outcomes. Better understanding of the longer-term consequences of the observed reductions in BMD is needed. Clinical Trials Registration: NCT00867048. © 2017 American Society for Bone and Mineral Research.
The value of N staging with the positive lymph node ratio, and splenectomy, for remnant gastric cancer: A multicenter retrospective study
Authors: Son Sang‐Yong , Kong Seong‐Ho , Ahn Hye Seong , Park Young Suk , Ahn Sang‐Hoon , Suh Yun‐Suhk , Park Do Joong , Lee Hyuk‐Joon , Kim Hyung‐Ho , Yang Han‐Kwang
Published: June 2017

Background

Surgery for remnant gastric cancer (RGC) frequently fails to obtain the >15 lymph nodes necessary for tumor‐node‐metastasis (TNM) staging. We aimed to evaluate the utility of the recently developed tumor‐ratio‐metastasis (TRM) staging system. We also examined the pattern of lymph node metastasis and the role of prophylactic splenectomy in RGC.

Methods

Between May 2003 and December 2012, data from 170 patients who underwent surgery for RGC were retrospectively analyzed.

Results

RGC arising after previous benign disease (n = 46) was associated with retrieval of more lymph nodes (27.3 vs 10.0; P < 0.001), and a lower rate of retrieving ≤15 lymph nodes (15.6% vs 77.4%, P < 0.001), than after previous malignant disease (n = 122). The 5 year survival rate according to TNM staging was 75% in stage I, 77.1% in stage II, and 23.5% in stage III, whereas by TRM staging it was 75%, 81.6%, and 23.2%, respectively. Overall survival was not different between the splenectomy and non‐splenectomy groups at each stage (P = 0.751, 0.723, 0.151, and 0.706 for stage I, II, III, and IV, respectively).

Conclusion

The analyses did not identify a survival benefit from prophylactic splenectomy or show an improvement in staging with the TRM system for RGC.
Point‐of‐Care Ultrasound in General Surgery Residency Training: A Proposal for Milestones in Graduate Medical Education Ultrasound
Authors: Beal Eliza W. , Sigmond Benjamin R. , Sage‐Silski Latifa , Lahey Samantha , Nguyen Victor , Bahner David P.
Published: June 2017

The use of point‐of‐care ultrasound (US) in the clinical setting has undergone massive growth, although its incorporation into training and practice is variable. Surgeons are interested in using point‐of‐care US and can incorporate it effectively into clinical practice. However, the current state of point‐of‐care US training in general surgery is inadequate. The Accreditation Council for Graduate Medical Education introduced the Milestones Project to evaluate resident and fellow performance. Emergency medicine is the only specialty with a point‐of‐care US milestone. We have successfully implemented a US training program into our general surgery residency curriculum and now propose milestones in point‐of‐care US for all general surgery residents.
Seasonal variability in phytoplankton stable carbon isotope ratios and bacterial carbon sources in a shallow Dutch lake
Authors: Lammers J. M. , Reichart G. J. , Middelburg J. J.
Published: June 2017

Ecosystem metabolism of lakes strongly depends on the relative importance of local vs. allochthonous carbon sources and on microbial food‐web functioning and structure. Over the year ecosystem metabolism varies as a result of seasonal changes in environmental parameters such as nutrient levels, light, temperature, and variability in the food web. This is reflected in isotopic compositions of phytoplankton and bacteria. Here, we present the results of a 17‐month study on carbon dynamics in two basins of Lake Naarden, The Netherlands. One basin was restored after anthropogenic eutrophication, whereas the other basin remained eutrophic. We analyzed natural stable carbon isotope abundances (δ13C) of dissolved inorganic carbon, dissolved organic carbon and macrophytes, and combined these data with compound‐specific δ13C analyses of phospholipid‐derived fatty acids, produced by phytoplankton and bacteria. Isotopic fractionation (ε) between phytoplankton biomass and CO2(aq) was similar for diatoms and other eukaryotic phytoplankton, and differences between sampling sites were small. Highest ε values were observed in winter with values of 23.5 ± 0.6‰ for eukaryotic phytoplankton and 13.6 ± 0.3‰ for cyanobacteria. Lowest ε values were observed in summer: 10.5 ± 0.3‰ for eukaryotic phytoplankton and 2.7 ± 0.1‰ for cyanobacteria. The annual range in δ13Cbact was between 6.9‰ and 8.2‰ for the restored and eutrophic basin, respectively, while this range was between 11.6‰ and 13.1‰ for phytoplankton in the restored and eutrophic basin, respectively. Correlations between δ13Cphyto and δ13Cbact were strong at both sites. During summer and fall, bacterial biomass derives mainly from locally produced organic matter, with minor allochthonous contributions. Conversely, during winter, bacterial dependence on allochthonous carbon was 39–77% at the restored site, and 17–46% at the eutrophic site.
Stable Covalently Photo‐Crosslinked Poly(Ionic Liquid) Membrane with Gradient Pore Size
Authors: Dani Alessandro , Täuber Karoline , Zhang Weiyi , Schlaad Helmut , Yuan Jiayin
Published: June 2017

Porous polyelectrolyte membranes stable in a highly ionic environment are obtained by covalent crosslinking of an imidazolium‐based poly(ionic liquid). The crosslinking reaction involves the UV light‐induced thiol–ene (click) chemistry, and the phase separation, occurring during the crosslinking step, generates a fully interconnected porous structure in the membrane. The porosity is on the order of the micrometer scale and the membrane shows a gradient of pore size across the membrane cross‐section. The membrane can separate polystyrene latex particles of different size and undergoes actuation in contact with acetone due to the asymmetric porous structure.
Microstructural Characterization and Mechanical Properties across Thickness of Ultra‐Heavy Steel Plate
Authors: Zhou Tao , Yu Hao , Wang Shaoyang
Published: June 2017

The microstructural homogeneity across thickness and the interior toughness are significant factors challenging the development of ultra‐heavy steel plate (above 200 mm) limited by the thermal transfer capacity of material and the loading capacity of mill. A complete understanding of the relationship between processing, structure, and property is essential for the optimization of alloying and heat treatment of ultra‐heavy steel plate. Hence, in the present work, the authors focus on the microstructural evolution and resultant mechanical properties across the thickness of ultra‐heavy steel plate under three potential heat treatment technologies, including quenching and tempering, double quenching and tempering, and intercritical quenching and tempering. The results show that the refined signal‐phase lath martensite microstructure after double quenching technology can improve toughness stability, while dual‐phase intercritical ferrite‐martensite microstructure resulted from intercritical quenching technology achieves excellent toughness stability and ductility, and a potential optimal combination of strength and toughness for ultra‐heavy steel plate. However, limited cooling capacity of the interior leads to the formation of massive coarse martensite/austenite constituents with high carbon concentration, which significantly deteriorate the toughness. Thus, the control or suppression of coarse martensite/austenite constituents is critical for optimization of low‐alloyed ultra‐heavy steel plate.
Easy as AcHGzrjq: The Quick Letter Name Knowledge Assessment
Authors: Tortorelli Laura S. , Bowles Ryan P. , Skibbe Lori E.
Published: June 2017

A firm foundation in alphabet knowledge is critical for children learning to read. Under new literacy standards, letter name knowledge in preschool and kindergarten can function as a gatekeeper to the rest of the curriculum. Teachers need data about their students’ alphabet knowledge early and often to plan differentiated instruction that moves all students forward in their literacy development. This article describes the Quick Letter Name Knowledge Assessment (Q‐LNK), a rigorous, research‐based letter name knowledge assessment designed for screening and benchmark testing that can be administered in less than a minute per student. The authors discuss the need for alphabet screening and benchmark assessments, the research on how students develop knowledge of letter names, and how the Q‐LNKassessment was developed and tested. The procedure for using the Q‐LNKis illustrated with the description of a teacher administering, scoring, and interpreting results from the assessment in her kindergarten class.
Danish Perioperative Nurses’ Documentation: A Complex, Multifaceted Practice Connected With Unit Culture and Nursing Leadership
Authors: Søndergaard Susanne F. , Lorentzen Vibeke , Sørensen Erik E. , Frederiksen Kirsten
Published: June 2017

Researchers have described the documentation practices of perioperative nurses as flawed and characterized by subjectivity and poor quality, which is often related to both the documentation tool and the nurses’ level of commitment. Studies suggest that documentation of nursing care in the OR places special demands on electronic health records (EHRs). The purpose of this study was to explore how the use of an EHR tailored to perioperative practice affects Danish perioperative nurses’ documentation practices. This study was a follow‐up to a baseline study from 2014. For three months in the winter of 2015 to 2016, six participants tested an EHR containing a Danish edition of a selected section of the Perioperative Nursing Data Set. This study relied on realistic evaluation and participant observations to generate data. We found that nursing leadership was essential for improving perioperative nurses’ documentation practices and that a tailored EHR may improve documentation practices.
The Information Regulation of Business Actors
Authors: Parella Kishanthi
Published: June 2017

A transnational legal order (TLO) is emerging regarding the role of businesses in respecting human rights. This legal order includes multistakeholder initiatives, international organization recommendations and guidelines, NGO certifications, and other voluntary instruments. Many of the norms within this TLO are nonbinding and therefore lack mandatory compliance; what they may possess is persuasive power, particularly when the norms are developed, endorsed, and managed by reputable organizations. It is that reputational, or legitimacy, advantage that matters for encouraging industry associations to comply with the nonbinding norms associated with these organizations. Industry associations and other business actors will gravitate more towards legitimacy enhancing organizations when their own legitimacy is at stake. They pivot towards public organizations such as the United Nations or private NGO initiatives like the Rainforest Alliance, seeking to associate themselves publicly with these organizations that enjoy more perceived legitimacy. These business relationships with legitimizing bodies can take the form of partnerships, certifications, or other arrangements where an industry association adopts and incorporates nonbinding norms when it otherwise might not. In this essay, I discuss three transnational legal processes that encourage industry associations, their members, and other business actors to abide by nonbinding transnational legal norms concerning business and human rights.
On the large-time behaviour of the solution of a stochastic differential equation driven by a Poisson point process
Authors: Nassar Elma , Pardoux Etienne
Published: June 2017

We study a stochastic differential equation driven by a Poisson point process, which models the continuous change in a population's environment, as well as the stochastic fixation of beneficial mutations that might compensate for this change. The fixation probability of a given mutation increases as the phenotypic lagXtbetween the population and the optimum grows larger, and successful mutations are assumed to fix instantaneously (leading to an adaptive jump). Our main result is that the process is transient (i.e. converges to -∞, so that continued adaptation is impossible) if the rate of environmental changevexceeds a parameterm, which can be interpreted as the rate of adaptation in case every beneficial mutation becomes fixed with probability 1. Ifv<m, the process is Harris recurrent and possesses a unique invariant probability measure, while in the limiting casem=v, Harris recurrence with an infinite invariant measure or transience depends upon additional technical conditions. We show how our results can be extended to a class of time varying rates of environmental change.
Asymptotics for the discrete-time average of the geometric Brownian motion and Asian options
Authors: Pirjol Dan , Zhu Lingjiong
Published: June 2017

The time average of geometric Brownian motion plays a crucial role in the pricing of Asian options in mathematical finance. In this paper we consider the asymptotics of the discrete-time average of a geometric Brownian motion sampled on uniformly spaced times in the limit of a very large number of averaging time steps. We derive almost sure limit, fluctuations, large deviations, and also the asymptotics of the moment generating function of the average. Based on these results, we derive the asymptotics for the price of Asian options with discrete-time averaging in the Black–Scholes model, with both fixed and floating strike.
Psychotherapeutische Versorgung von Geflüchteten aus der Sicht niedergelassener Psychotherapeuten in Deutschland
Authors: Thöle Anna-Maria , Penka Simone , Brähler Elmar , Heinz Andreas , Kluge Ulrike
Published: June 2017

Zusammenfassung. Angesichts gestiegener Geflüchtetenzahlen und sich ändernder Regelungen zur gesundheitlichen Versorgung von Asylsuchenden ist anzunehmen, dass perspektivisch mehr niedergelassene Psychotherapeuten Geflüchtete behandeln werden. Bisher gibt es in Deutschland kaum Studien, die sich mit den Schwierigkeiten in der psychotherapeutischen Arbeit mit Geflüchteten aus Sicht niedergelassener Psychotherapeuten befassen. Ziel des vorliegenden Beitrags ist es, diese Lücke zu schließen. Bundesweit wurden mit 20 niedergelassenen Psychotherapeuten problemzentrierte Interviews geführt, die entsprechend den Prinzipien der Grounded Theory ausgewertet wurden. Insgesamt wurden acht Schwierigkeiten identifiziert, die das psychotherapeutische Setting beeinflussen: Die Lebensbedingungen von Asylsuchenden in Deutschland (1), die Finanzierung der psychotherapeutischen Versorgung von Geflüchteten (2), kulturelle Unterschiede (3), fehlende Vernetzung (4), die Arbeit mit Dolmetschern (5), das Hören von Berichten über traumatische Erlebnisse (6), die aktuelle Situation im Heimatland (7), sowie das Gesundheitssystem und das Jobcenter (8). Der Fokus auf kulturellen, sprachlichen und finanziellen Barrieren in bisherigen Untersuchungen wird von den befragten Psychotherapeuten um das Zusammenspiel mit weiteren Schwierigkeiten ergänzt. Abgeleitet aus den Ergebnissen werden Empfehlungen zur Erleichterung der Arbeit der niedergelassenen Psychotherapeuten mit Geflüchteten ausgesprochen.
Membrane-binding and activation of LKB1 by phosphatidic acid is essential for development and tumour suppression
Authors: Dogliotti Giada , Kullmann Lars , Dhumale Pratibha , Thiele Christian , Panichkina Olga , Mendl Gudrun , Houben Roland , Haferkamp Sebastian , Püschel Andreas W. , Krahn Michael P.
Published: June 2017

The serine/threonine kinase LKB1 regulates various cellular processes such as cell proliferation, energy homeostasis and cell polarity and is frequently downregulated in various tumours. Many downstream pathways controlled by LKB1 have been described but little is known about the upstream regulatory mechanisms. Here we show that targeting of the kinase to the membrane by a direct binding of LKB1 to phosphatidic acid is essential to fully activate its kinase activity. Consequently, LKB1 mutants that are deficient for membrane binding fail to activate the downstream target AMPK to control mTOR signalling. Furthermore, the in vivo function of LKB1 during development of Drosophila depends on its capacity to associate with membranes. Strikingly, we find LKB1 to be downregulated in malignant melanoma, which exhibit aberrant activation of Akt and overexpress phosphatidic acid generating Phospholipase D. These results provide evidence for a fundamental mechanism of LKB1 activation and its implication in vivo and during carcinogenesis.
Attenuation of RNA polymerase II pausing mitigates BRCA1-associated R-loop accumulation and tumorigenesis
Authors: Zhang Xiaowen , Chiang Huai-Chin , Wang Yao , Zhang Chi , Smith Sabrina , Zhao Xiayan , Nair Sreejith J. , Michalek Joel , Jatoi Ismail , Lautner Meeghan , Oliver Boyce , Wang Howard , Petit Anna , Soler Teresa , Brunet Joan , Mateo Francesca , Angel Pujana Miguel , Poggi Elizabeth , Chaldekas Krysta , Isaacs Claudine , Peshkin Beth N. , Ochoa Oscar , Chedin Frederic , Theoharis Constantine , Sun Lu-Zhe , Curiel Tyler J. , Elledge Richard , Jin Victor X. , Hu Yanfen , Li Rong
Published: June 2017

Most BRCA1-associated breast tumours are basal-like yet originate from luminal progenitors. BRCA1 is best known for its functions in double-strand break repair and resolution of DNA replication stress. However, it is unclear whether loss of these ubiquitously important functions fully explains the cell lineage-specific tumorigenesis. In vitro studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcription and genetic instability. Here we show that R-loops accumulate preferentially in breast luminal epithelial cells, not in basal epithelial or stromal cells, of BRCA1 mutation carriers. Furthermore, R-loops are enriched at the 5′ end of those genes with promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of Cobra1, which encodes a Pol II-pausing and BRCA1-binding protein, ameliorates R-loop accumulation and reduces tumorigenesis in Brca1-knockout mouse mammary epithelium. Our studies show that Pol II pausing is an important contributor to BRCA1-associated R-loop accumulation and breast cancer development.
Uniform electroactive fibre-like micelle nanowires for organic electronics
Authors: Li Xiaoyu , Wolanin Piotr J. , MacFarlane Liam R. , Harniman Robert L. , Qian Jieshu , Gould Oliver E. C. , Dane Thomas G. , Rudin John , Cryan Martin J. , Schmaltz Thomas , Frauenrath Holger , Winnik Mitchell A. , Faul Charl F. J. , Manners Ian
Published: June 2017

Micelles formed by the self-assembly of block copolymers in selective solvents have attracted widespread attention and have uses in a wide variety of fields, whereas applications based on their electronic properties are virtually unexplored. Herein we describe studies of solution-processable, low-dispersity, electroactive fibre-like micelles of controlled length from π-conjugated diblock copolymers containing a crystalline regioregular poly(3-hexylthiophene) core and a solubilizing, amorphous regiosymmetric poly(3-hexylthiophene) or polystyrene corona. Tunnelling atomic force microscopy measurements demonstrate that the individual fibres exhibit appreciable conductivity. The fibres were subsequently incorporated as the active layer in field-effect transistors. The resulting charge carrier mobility strongly depends on both the degree of polymerization of the core-forming block and the fibre length, and is independent of corona composition. The use of uniform, colloidally stable electroactive fibre-like micelles based on common π-conjugated block copolymers highlights their significant potential to provide fundamental insight into charge carrier processes in devices, and to enable future electronic applications.
An L-threonine transaldolase is required for L-threo-β-hydroxy-α-amino acid assembly during obafluorin biosynthesis
Authors: Scott Thomas A. , Heine Daniel , Qin Zhiwei , Wilkinson Barrie
Published: June 2017

β-Lactone natural products occur infrequently in nature but possess a variety of potent and valuable biological activities. They are commonly derived from β-hydroxy-α-amino acids, which are themselves valuable chiral building blocks for chemical synthesis and precursors to numerous important medicines. However, despite a number of excellent synthetic methods for their asymmetric synthesis, few effective enzymatic tools exist for their preparation. Here we report cloning of the biosynthetic gene cluster for the β-lactone antibiotic obafluorin and delineate its biosynthetic pathway. We identify a nonribosomal peptide synthetase with an unusual domain architecture and an L-threonine:4-nitrophenylacetaldehyde transaldolase responsible for (2S,3R)-2-amino-3-hydroxy-4-(4-nitrophenyl)butanoate biosynthesis. Phylogenetic analysis sheds light on the evolutionary origin of this rare enzyme family and identifies further gene clusters encoding L-threonine transaldolases. We also present preliminary data suggesting that L-threonine transaldolases might be useful for the preparation of L-threo-β-hydroxy-α-amino acids.
A pan-cancer genome-wide analysis reveals tumour dependencies by induction of nonsense-mediated decay
Authors: Hu Zhiyuan , Yau Christopher , Ahmed Ahmed Ashour
Published: June 2017

Nonsense-mediated decay (NMD) eliminates transcripts with premature termination codons. Although NMD-induced loss-of-function has been shown to contribute to the genesis of particular cancers, its global functional consequence in tumours has not been characterized. Here we develop an algorithm to predict NMD and apply it on somatic mutations reported in The Cancer Genome Atlas. We identify more than 73 K mutations that are predicted to elicit NMD (NMD-elicit). NMD-elicit mutations in tumour suppressor genes (TSGs) are associated with significant reduction in gene expression. We discover cancer-specific NMD-elicit signatures in TSGs and cancer-associated genes. Our analysis reveals a previously unrecognized dependence of hypermutated tumours on hypofunction of genes that are involved in chromatin remodelling and translation. Half of hypermutated stomach adenocarcinomas are associated with NMD-elicit mutations of the translation initiators LARP4B and EIF5B. Our results unravel strong therapeutic opportunities by targeting tumour dependencies on NMD-elicit mutations.
Iron-mediated soil carbon response to water-table decline in an alpine wetland
Authors: Wang Yiyun , Wang Hao , He Jin-Sheng , Feng Xiaojuan
Published: June 2017

The tremendous reservoir of soil organic carbon (SOC) in wetlands is being threatened by water-table decline (WTD) globally. However, the SOC response to WTD remains highly uncertain. Here we examine the under-investigated role of iron (Fe) in mediating soil enzyme activity and lignin stabilization in a mesocosm WTD experiment in an alpine wetland. In contrast to the classic ‘enzyme latch’ theory, phenol oxidative activity is mainly controlled by ferrous iron [Fe(II)] and declines with WTD, leading to an accumulation of dissolvable aromatics and a reduced activity of hydrolytic enzyme. Furthermore, using dithionite to remove Fe oxides, we observe a significant increase of Fe-protected lignin phenols in the air-exposed soils. Fe oxidation hence acts as an ‘iron gate’ against the ‘enzyme latch’ in regulating wetland SOC dynamics under oxygen exposure. This newly recognized mechanism may be key to predicting wetland soil carbon storage with intensified WTD in a changing climate.
Engineered botulinum neurotoxin B with improved efficacy for targeting human receptors
Authors: Tao Liang , Peng Lisheng , Berntsson Ronnie P.-A. , Liu Sai Man , Park SunHyun , Yu Feifan , Boone Christopher , Palan Shilpa , Beard Matthew , Chabrier Pierre-Etienne , Stenmark Pål , Krupp Johannes , Dong Min
Published: June 2017

Botulinum neurotoxin B is a Food and Drug Administration-approved therapeutic toxin. However, it has lower binding affinity toward the human version of its major receptor, synaptotagmin II (h-Syt II), compared to mouse Syt II, because of a residue difference. Increasing the binding affinity to h-Syt II may improve botulinum neurotoxin B’s therapeutic efficacy and reduce adverse effects. Here we utilized the bacterial adenylate cyclase two-hybrid method and carried out a saturation mutagenesis screen in the Syt II-binding pocket of botulinum neurotoxin B. The screen identifies E1191 as a key residue: replacing it with M/C/V/Q enhances botulinum neurotoxin B binding to human synaptotagmin II. Adding S1199Y/W or W1178Q as a secondary mutation further increases binding affinity. Mutant botulinum neurotoxin B containing E1191M/S1199Y exhibits ~11-fold higher efficacy in blocking neurotransmission than wild-type botulinum neurotoxin B in neurons expressing human synaptotagmin II, demonstrating that enhancing receptor binding increases the overall efficacy at functional levels. The engineered botulinum neurotoxin B provides a platform to develop therapeutic toxins with improved efficacy.
Observation of reflectionless absorption due to spatial Kramers–Kronig profile
Authors: Ye Dexin , Cao Cheng , Zhou Tianyi , Huangfu Jiangtao , Zheng Guoan , Ran Lixin
Published: June 2017

As a fundamental phenomenon in electromagnetics and optics, material absorption has been extensively investigated for centuries. However, omnidirectional, reflectionless absorption in inhomogeneous media has yet to be observed. Previous research on transformation optics indicated that such absorption cannot easily be implemented without involving gain media. A recent theory on wave propagation, however, implies the feasibility to implement such absorption requiring no gain, provided that the permittivity profile of this medium can satisfy the spatial Kramers–Kronig relations. In this work, we implement such a profile over a broad frequency band based on a novel idea of space–frequency Lorentz dispersion. A wideband, omnidirectionally reflectionless absorption is then experimentally observed in the gigahertz range, and is in good agreement with theoretical analysis and full-wave simulations. The proposed method based on the space–frequency dispersion implies the practicability to construct gain-free omnidirectionally non-reflecting absorbers.
Designed α-sheet peptides suppress amyloid formation in Staphylococcus aureus biofilms
Authors: Bleem Alissa , Francisco Robyn , Bryers James D. , Daggett Valerie
Published: June 2017

Nosocomial infections affect hundreds of millions of patients worldwide each year, and ~60% of these infections are associated with biofilm formation on an implanted medical device. Biofilms are dense communities of microorganisms in which cells associate with surfaces and each other using a self-produced extracellular matrix composed of proteins, polysaccharides, and genetic material. Proteins in the extracellular matrix take on a variety of forms, but here we focus on functional amyloid structures. Amyloids have long been associated with protein misfolding and neurodegenerative diseases, but recent research has demonstrated that numerous bacterial species utilize the amyloid fold to fortify the biofilm matrix and resist disassembly. Consequently, these functional amyloids, in particular the soluble oligomeric intermediates formed during amyloidogenesis, represent targets to destabilize the extracellular matrix and interrupt biofilm formation. Our previous studies suggested that these amyloidogenic intermediates adopt a non-standard structure, termed “α-sheet”, as they aggregate into soluble oligomeric species. This led to the design of complementary α-sheet peptides as anti-α-sheet inhibitors; these designs inhibit amyloidogenesis in three unrelated mammalian disease-associated systems through preferential binding of soluble oligomers. Here we show that these anti-α-sheet peptides inhibit amyloid formation in Staphylococcus aureus biofilms. Furthermore, they inhibit aggregation of pure, synthetic phenol soluble modulin α1, a major component of Staphylococcus aureus functional amyloids. As it aggregates phenol soluble modulin α1 adopts α-helix then α-sheet and finally forms β-sheet fibrils. The binding of the designed peptide inhibitors coincides with the formation of α-sheet.
Dislocations interaction induced structural instability in intermetallic Al2Cu
Authors: Zhou Qing , Wang Jian , Misra Amit , Huang Ping , Wang Fei , Xu Kewei
Published: June 2017

Intermetallic precipitates are widely used to tailor mechanical properties of structural alloys but are often destabilized during plastic deformation. Using atomistic simulations, we elucidate structural instability mechanisms of intermetallic precipitates associated with dislocation motion in a model system of Al2Cu. Interaction of non-coplanar <001> dislocation dipoles during plastic deformation results in anomalous reactions—the creation of vacancies accompanied with climb and collective glide of <001> dislocation associated with the dislocation core change and atomic shuffle—accounting for structural instability in intermetallic Al2Cu. This process is profound with decreasing separation of non-coplanar dislocations and increasing temperature and is likely to be operative in other non-cubic intermetallic compounds as well.
The role of the FliD C-terminal domain in pentamer formation and interaction with FliT
Authors: Kim Hee Jung , Yoo Woongjae , Jin Kyeong Sik , Ryu Sangryeol , Lee Hyung Ho
Published: June 2017

Flagellar biogenesis is controlled by a negative feedback loop. When FliD was secreted at the late step of flagellar assembly, the FliD-FliT complex disassembled and free FliT bound to the FlhDC complex, a master regulator of flagellar biogenesis, subsequently inhibiting the overall expression of flagellar proteins. In this study, we analyzed the role of the FliD C-terminal domain in pentamer formation and interaction with FliT. Our study showed that the FliD L443R mutant exists as a monomer in solution, indicating that the Leu443 residue of FliD, which contributes to its interaction with FliT, plays a crucial role in the pentameric oligomerization of FliD. Consistently, the increased levels of free FliT proteins caused by FliD L443R mutation had negative effects on the gene expression of flagellar synthesis and reduced the expression of flagellar proteins. The lengths of flagella in each cell were significantly reduced in L443R mutant strain, suggesting that normal flagellar biogenesis was impeded. These results suggest that the C-terminal domain of FliD plays a crucial role in the pentameric oligmerization of FliD and the binding of FliT to the C-terminal domain of FliD is critical to inhibit the premature assembly of the FliD pentamer in the cytosol.
Evaluation of muscular changes by ultrasound Nakagami imaging in Duchenne muscular dystrophy
Authors: Weng Wen-Chin , Tsui Po-Hsiang , Lin Chia-Wei , Lu Chun-Hao , Lin Chun-Yen , Shieh Jeng-Yi , Lu Frank Leigh , Ee Ting-Wei , Wu Kuan-Wen , Lee Wang-Tso
Published: June 2017

Duchenne muscular dystrophy (DMD) is the most common debilitating muscular disorder. Developing a noninvasive measure for monitoring the progression of this disease is critical. The present study tested the effectiveness of using ultrasound Nakagami imaging to evaluate the severity of the dystrophic process. A total of 47 participants (40 with DMD and 7 healthy controls) were recruited. Patients were classified into stage 1 (presymptomatic and ambulatory), stage 2 (early nonambulatory), and stage 3 (late nonambulatory). All participants underwent ultrasound examinations on the rectus femoris, tibialis anterior, and gastrocnemius. The results revealed that the ultrasound Nakagami parameter correlated positively with functional severity in the patients with DMD. The median Nakagami parameter of the gastrocnemius muscle increased from 0.50 to 0.85, corresponding to the largest dynamic range between normal and stage 3. The accuracy, sensitivity, and specificity of diagnosing walking function were 85.52%, 76.31%, and 94.73%, respectively. The Nakagami parameter of the rectus femoris and gastrocnemius muscles correlated negatively with the 6-minute walking distance in the ambulatory patients. Therefore, changes in the Nakagami parameter for the gastrocnemius muscle are suitable for monitoring disease progression in ambulatory patients and for predicting ambulation loss. Ultrasound Nakagami imaging shows potential for evaluating patients with DMD.