bluuebunny/crossref_metadata_2025 huggingface dataset:
Co‐immobilized Whole Cells with ω‐Transaminase and Ketoreductase Activities for Continuous‐Flow Cascade Reactions
Authors: Nagy‐Győr László , Abaházi Emese , Bódai Viktória , Sátorhelyi Péter , Erdélyi Balázs , Balogh‐Weiser Diána , Paizs Csaba , Hornyánszky Gábor , Poppe László
Published: June 2018

An improved sol–gel process involving the use of hollow silica microspheres as a supporting additive was applied for the co‐immobilization of whole cells of Escherichia coli with Chromobacterium violaceum ω‐transaminase activity and Lodderomyces elongisporus with ketoreductase activity. The co‐immobilized cells with two different biocatalytic activities could perform a cascade of reactions to convert racemic 4‐phenylbutan‐2‐amine or heptan‐2‐amine into a nearly equimolar mixture of the corresponding enantiomerically pure R amine and S alcohol even in continuous‐flow mode. The novel co‐immobilized whole‐cell system proved to be an easy‐to‐store and durable biocatalyst.
High‐Throughput Measurement of Small‐Molecule Enantiopurity by Using Flow Cytometry
Authors: Tan Zhesen , Heemstra Jennifer M.
Published: June 2018

Fluorescence‐activated cell sorting (FACS) offers a powerful approach to high‐throughput library screening in directed evolution experiments. However, FACS is rarely used in the evolution of stereoselective enzymes, due to the difficulty of designing fluorescence‐based assays for measuring enantiopurity. Here, we describe a new FACS‐based enantiopurity analysis approach that overcomes these limitations by using enantiomeric DNA biosensors labeled with orthogonal fluorophores. By co‐encapsulating the biosensors with a mixture of target enantiomers in microfluidic droplets, we could demonstrate the use of FACS to differentiate between droplets having various levels of target enantiopurity. We envision the utility of this method for high‐throughput screening of enantiopurity in the directed evolution of stereoselective enzymes, thereby facilitating the discovery of new asymmetric biocatalysts for the synthesis of pharmaceuticals and other high‐value chemicals.
Nanoparticle@Metal‐Organic Frameworks as a Template for Hierarchical Porous Carbon Sponges
Authors: Salazar‐Beltrán Daniel , Cabello Carlos Palomino , Guzmán‐Mar Jorge Luis , Hinojosa‐Reyes Laura , Palomino Gemma Turnes , Maya Fernando
Published: June 2018

The preparation of hierarchical porous carbon sponges (HCS) from metal oxide nanoparticle@metal‐organic frameworks is reported. ZnO nanoparticles are partially converted to zeolitic imidazolate framework‐8 (ZIF‐8) crystals in presence of n‐butylamine to obtain ZnO@ZIF‐8 porous hybrids. After direct carbonization, followed by ZnO acidic etching, ZnO@ZIF‐8 crystals were converted to submicrometric HCS. Due to the high surface area and accessible porosity, combining micro‐ and mesoporosity of HCS, their application for the extraction of water pollutants was studied by preparing HCS/polymer membranes, and showed a high efficiency for the fast (650 L m−2 h−1) removal of plastic degradation by‐products (DBP, dibutyl phthalate. DEHP, bis(2‐n‐ethylhexyl)phthalate). DBP and DEHP breakthroughs were lower than 3 % after the filtration of 100 mL of water containing simultaneously both phthalates at a high concentration level (300 μg L−1, each). HCS/polymer membranes were reusable up to 5 times, maintaining their extraction capacity, with relative errors of 6 % for DBP, and <1 % for DEHP.
Modular Preparation of Graphene‐Based Functional Architectures through Two‐Step Organic Reactions: Towards High‐Performance Energy Storage
Authors: Zhang Xiaoyan , Hou Lili , Richard Fanny , Samorì Paolo
Published: June 2018

Graphene‐based materials have recently attracted much attention due to their extraordinary physical and chemical properties, which make them attractive candidates for many technological applications in sensing, optoelectronics, catalysis, and energy storage. Their chemical functionalization is key to tuning their properties. Herein, a novel two‐step synthetic approach, which enables a high degree of covalent functionalization of graphene oxide (GO) is devised, thereby making the facile attachment of various robust functional molecules possible. Such a process relies initially on the grafting of an ethylenediamine linker followed by a second step consisting of the condensation reaction between aldehyde and amine groups to form imine bonds. As test beds, two kinds of graphene‐based functional systems, namely, porphyrin‐modified GO and ferrocene‐modified GO, are prepared. Such hybrid systems are characterized by various spectroscopic and microscopic techniques. The degree of functionalization is quantified as the attachment of one porphyrin or ferrocene unit to every 34 or 77 carbon atoms of the GO scaffold, respectively, which is much higher than that of values obtained upon using various established chemical approaches to functionalize GO, such as condensation, cycloaddition, or coupling reactions. For the first time, the reduced form of ferrocene‐modified GO was employed as an electrode material in supercapacitors, showing a specific capacitance of 127 F g−1 at a current density of 1 A g−1, with capacitance retention of about 93 % after 5000 cycles at the same current density; this demonstrates great potential for application in high‐performance energy‐storage devices.
Influence of Crosshead Speed and Particle Size on the Bursting Behavior of Agar Beads
Authors: Höft Steffi , Waluga Thomas , Scholl Stephan
Published: June 2018

Die mechanische Charakterisierung von Enzym‐ und Zellimmobilisaten stellt eine wesentliche Voraussetzung für deren Auswahl und Design zum Einsatz in Bioreaktoren dar. Vor diesem Hintergrund wurde das Bruchverhalten von Agarperlen unterschiedlicher Agarkonzentrationen mithilfe eines Texture Analyzers untersucht. Hierbei konnten ein Einfluss des umgebenden Mediums ausgeschlossen und signifikante Abhängigkeiten des Bruchverhaltens von Beanspruchungsgeschwindigkeit und Perlengröße festgestellt werden.
Chinin, ein legendäres Alkaloid
Authors: Rudo Anna , Zeller Klaus‐Peter , Siehl Hans‐Ullrich , Berger Stefan , Sicker Dieter
Published: June 2018

Chinin, schon 1820 als eines der ersten Alkaloide rein isoliert, ist eines der wertvollsten Medikamente, mit dem seit Jahrhunderten und noch heute Malaria behandelt wird. Wie seine Quelle, der Chinarindenbaum, ist es legendenumwoben. Wir belegen mit Zitaten aus Reviews sowohl diesen spektakulären Hintergrund als auch die Anstrengungen zur Isolierung, Strukturaufklärung und Totalsynthese, die die Organische Chemie vorangebracht haben. Wenn wir Tonic Water oder Gin Tonic trinken, nehmen wir selbst Chinin als Bitterstoff auf. Wir zeigen seine eindrucksvolle blaue Fluoreszenz unter UV‐Bestrahlung und diskutieren weitere Anwendungen. Im Zentrum des Artikels steht die spektroskopische Analyse des Alkaloids für das wir eine Laborvorschrift zum Isolieren aus Chinarinde angeben.
Verifiable Chebyshev maps‐based chaotic encryption schemes with outsourcing computations in the cloud/fog scenarios
Authors: Li Jing , Wang Licheng , Wang Lihua , Wang Xianmin , Huang Zhengan , Li Jin
Published: June 2018

Based on cloud servers' powerful storage and computing resources, users can store mass encrypted data in the cloud and outsource complex encryption computations to the cloud servers. Since cloud servers cannot be completely trusted, then data privacy and integrity are concerned about hot issues. We focus on the following problems in outsourced encryptions: how to protect the data privacy and how to check the integrity of data and the correctness of cloud server's outsourcing computations. In this paper, we at first propose a verifiable chaotic encryption based on Chebyshev polynomials. The scheme supports verifiable function for data integrity. To further improve the efficiency of the scheme, a corresponding outsourced encryption scheme is constructed, where the heavy overhead evaluations of Chebyshev polynomials are transferred from the user side to the cloud server. The outsourced encryption also provides the checkability for data integrity and correctness of cloud computations. The scheme is suitable for mobile users with limited computing resources. Moreover, the newly proposed scheme no longer depends upon the simple heuristic analysis. It achieves the indistinguishability under chosen‐ciphertext attacks (IND‐CCA) in the standard model based on the Chebyshev‐based Decisional Diffie‐Hellman (CDDH) assumption. Thus, we answer a long‐term open problem for building a chaotic encryption scheme with provable security in the sense of the IND‐CCA.
Boron‐Substituted Coronene: Intriguing Geometric and Electronic Properties, and Large Nonlinear Optical Response
Authors: Sun Wei‐Ming , Chen Cheng‐Yun , Li Chun‐Yan , Wu Di , Kang Jie , Li Ying , Li Zhi‐Ru
Published: June 2018

By substituting boron atoms for selected carbon atoms of a graphene quantum dot (GQD) model, namely a coronene molecule, the substituent effect on its geometric and electronic structure, as well as nonlinear optical response has been systemically investigated in theory. Our computations reveal that the boron substitution leads to a similar noncentrosymmetric apophysis structure for the boron‐substituted coronene in singlet and triplet states. Noticeably, due to the small energy difference of 2.5 kcal mol−1 between the singlet and triplet states, the boron‐substituted molecule can easily be switched between the antiferromagnetic (singlet state) and ferromagnetic (triplet state) state by slightly changing the external conditions. Notably, the boron‐substituted coronene exhibits a considerably large first hyperpolarizability of 36241 au, because boron substitution yields a raised structure with an intermediate singlet diradical character. Hence, it is expected that this study not only provides new insights for the boron‐substituent effect on the structure and properties of graphene but also may promote practical applications of GQDs in the fields of spintronics and nonlinear optics.
Complexes of Crown Ether Macrocycles with Methyl Guanidinium: Insights into the Capture of Charge in Peptides
Authors: Avilés‐Moreno Juan Ramón , Berden Giel , Oomens Jos , Martínez‐Haya Bruno
Published: June 2018

Crown ethers are well known as modulating agents of protein function and interactions. The action of crown ethers is driven by an alteration of the charged moieties of proteins through the capping of cationic amino acid side chains. This study evaluates the conformational features involved in the binding of crown ethers to the side chain of arginine. For this purpose, isolated complexes of methyl guanidinium with 12‐crown‐4 and 18‐crown‐6 are characterized with infrared action vibrational spectroscopy and quantum chemical computations. The conformational landscapes of the two complexes comprise an extensive ensemble of conformations close in energy. In the 12‐crown‐4 complex, the crown ether has the plane of its backbone approximately perpendicular to that of the guanidinium moiety and coordinates to two or three of its NHδ+ bonds. In the 18‐crown‐6 complex, the crown ether backbone is partially folded and tilted with respect to guanidinium and fixes its position in order to facilitate up to a four‐fold coordination in the complex. The access of the complexes to multiple conformations leads to broad band structures in the N−H stretching region of their vibrational spectra.
The Combination of Hydrogen and Methanol Production through Artificial Photosynthesis—Are We Ready Yet?
Authors: Le Trung‐Anh , Huynh Tan‐Phat
Published: June 2018

Because 100 % quantum efficiency for the photosynthetic production of H2 from H2O under visible illumination has been achieved recently, the oxidation of H2O to O2 remains the bottleneck to the overall water‐splitting reaction. Oxidation of CH4 to CH3OH might be combined with water reduction instead, so that H2 and CH3OH chemical fuels can be simultaneously produced through a one‐step process under solar illumination. This combination would be a promising approach towards a more sustainable future of chemistry, in which developing different strategies for artificial photosynthesis is of paramount importance. By using free and adsorbed HO. radicals on the semiconductor surface, CH4 can be activated to H3C. radicals and converted into CH3OH, respectively, with great selectivity up to 100 %. The present lack of efficient photosynthetic systems for the formation of H2 and CH3OH from abundant H2O and CH4 motivates future research for basic science and industrial applications.
Differences in the persistence of spatial memory deficits induced by a chronic stressor in adolescents compared to juveniles
Authors: Stylianakis Anthea A. , Harmon‐Jones Sylvia K. , Richardson Rick , Baker Kathryn D.
Published: June 2018

Adolescence is thought of as a stress‐sensitive developmental period. While many studies have compared adolescent responses to stress relative to that of adults, a growing body of work has examined stress responses in juveniles. Here we investigated if a chronic stressor has a differential effect on spatial memory in rats depending on whether it occurs during adolescence or the juvenile period. Male rats were exposed to the stress hormone corticosterone (Cort) in their drinking water, a vehicle control (2.5% ethanol), or water, for 7 days before being tested on a novel Object/Place task 6 days or 6 weeks later. Exposure to Cort or ethanol at either age impaired spatial memory at the 6‐day test. The ethanol induced impairment was attenuated 6 weeks later. However, rats given Cort during adolescence, but not the juvenile period, were still impaired. Together, these results suggest that adolescence is indeed a stress‐sensitive period.
A novel cardiac output response to stress test developed to improve diagnosis and monitoring of heart failure in primary care
Authors: Charman Sarah J. , Okwose Nduka C. , Stefanetti Renae J. , Bailey Kristian , Skinner Jane , Ristic Arsen , Seferovic Petar M. , Scott Mike , Turley Stephen , Fuat Ahmet , Mant Jonathan , Hobbs Richard F.D. , MacGowan Guy A. , Jakovljevic Djordje G.
Published: June 2018

Aims

Primary care physicians lack access to an objective cardiac function test. This study for the first time describes a novel cardiac output response to stress (CORS) test developed to improve diagnosis and monitoring of heart failure in primary care and investigates its reproducibility.

Methods and results

Prospective observational study recruited 32 consecutive primary care patients (age, 63 ± 9 years; female, n = 18). Cardiac output was measured continuously using the bioreactance method in supine and standing positions and during two 3 min stages of a step‐exercise protocol (10 and 15 steps per minute) using a 15 cm height bench. The CORS test was performed on two occasions, i.e. Test 1 and Test 2. There was no significant difference between repeated measures of cardiac output and stroke volume at supine standing and Stage 1 and Stage 2 step exercises (all P > 0.3). There was a significant positive relationship between Test 1 and Test 2 cardiac outputs (r = 0.92, P = 0.01 with coefficient of variation of 7.1%). The mean difference in cardiac output (with upper and lower limits of agreement) between Test 1 and Test 2 was 0.1 (−1.9 to 2.1) L/min, combining supine, standing, and step‐exercise data.

Conclusions

The CORS, as a novel test for objective evaluation of cardiac function, demonstrates acceptable reproducibility and can potentially be implemented in primary care.
Able to purchase? Agency problems in China's social health insurance system and the pitfalls of third‐party strategic purchasing
Authors: Liu Kai , He Alex Jingwei
Published: June 2018

The notion of strategic purchasing has gained increasing currency in the global health policy discourse. It is believed that an active prudent purchaser is able to act in the best interest of both government and consumers as a third party negotiating with providers for cost‐effective care. It would be wrong, however, to assume that the formation of a third‐party purchaser automatically leads to such desired outcomes. A variety of agency problems relating to incompetence often prevent purchasers from fulfilling their mandates, aggravating cost inflation. This study provides an alternative explanation for the rapid cost inflation in the Chinese health system, by focusing on the unique role played by the social health insurance administration. Provincial‐level panel data analysis reveals that misaligned bureaucratic incentives and limited administrative capacity of the social health insurance administration contribute significantly to rapidly escalating costs. This study argues that despite the merit of the notion of third‐party strategic purchasing, it must not be forgotten that effective purchasing hinges on certain crucial prerequisites that may not necessarily be present in reality. Appropriate alignment of the social health insurance administration's organizational mandates and development of its capacity is essential to China's move towards strategic purchasing of health services.
Management of intersex newborns: Legal and ethical developments
Authors: Dickens Bernard M.
Published: June 2018

Countries worldwide are increasingly expanding male/female binary sex classifications to recognize a third status. Intersex newborns may be included in this third category on birth certification. Parents, families, and communities require counselling and education to accommodate intersex newborns without stigma or discrimination. Whatever its biological or genetic origin, intersex status is a natural if relatively uncommon condition (one in 1500–2000 live births) that distinguishes sex from gender. The tendency of societies to recognize only male and female genders at birth has resulted in intersex children being subjected to invasive surgery and related, sometimes lifelong, medication to confirm them as male or female. On gaining maturity, some are severely distressed and resentful that early gender assignment was mistaken, particularly when excision of testes to enforce femininity or of ovaries to enforce masculinity has denied them procreative capacity. Emerging principles support postponement of such interventions until intersex individuals can make a gender choice for themselves.
Systematic review and meta‐analysis of complementary treatments for women with symptomatic endometriosis
Authors: Mira Ticiana A.A. , Buen Mariana M. , Borges Murilo G. , Yela Daniela A. , Benetti‐Pinto Cristina L.
Published: June 2018

Background

Despite advances in treatments for endometriosis, some symptoms persist owing to the chronic inflammation observed in this disease.

Objective

To identify resources, methods, and/or complementary treatments to alleviate the pain symptoms of endometriosis, and to identify adverse effects of treatments.

Search strategy

Lilacs, Scielo, PEDro, Scopus, Pubmed, CENTRAL Cochrane, Science Direct, and Google Scholar were searched for studies published in Portuguese, English, and Spanish to July 31, 2017, using the terms “physical therapy” OR “complementary treatment” AND “endometriosis”.

Selection criteria

Randomized controlled trials relating to complementary pelvic pain treatment and adverse effects.

Data collection and analysis

Eight studies were identified; two studies were included in the meta‐analysis.

Main results

The complementary interventions studied were acupuncture, exercise, electrotherapy, and yoga. All were inconclusive in affirming benefit, but demonstrated a positive trend in the treatment of symptoms of endometriosis. Meta‐analysis of acupuncture showed a significant benefit in pain reduction as compared with placebo (P=0.007).

Conclusions

Numerous complementary treatments have been used to alleviate the symptoms of endometriosis, but only acupuncture has demonstrated a significant improvement in outcomes. Nevertheless, other approaches demonstrated positive trends toward improving symptoms; this should encourage investigators to design controlled studies to support their applicability.
How information and communication technology affects decision‐making on innovation diffusion: An agent‐based modelling approach
Authors: Fernández‐Márquez Carlos M. , Vázquez Francisco J.
Published: June 2018

We introduce a computational agent‐based model of innovation diffusion that allows us to analyse the influence of information and communication technology (ICT) development on decision‐making. Model dynamics are based on local emulation between pairs of individuals that generate an evolving social network on which an innovation is virally spread (by word of mouth). Results suggest that ICT development affects the data usefulness for decision‐making by changing the topology of the social network (the means whereby the innovation is propagated). Paradoxically, a higher level of ICT development (providing a larger volume of data) narrows the differences between better and worse launch strategies, thus reducing data‐driven decision‐making usefulness, which then shows diminishing returns on the ICT level.
The Need for Cosmopolitan Literacy in a Global Age: Implications for Teaching Literature
Authors: Choo Suzanne S.
Published: June 2018

Given the realities of this increasingly connected, complex, and conflicting age, governments and policymakers around the world are recognizing the importance of global education. The field of literacy has not been immune to the pressure to globalize. Today, the notion of literacy must account not merely for social processes but also for global processes. The global turn in literacy studies affirms the cultural and linguistic diversity of students and acknowledges the need to empower them with a plurality of literacies—critical, digital, information, and multilingual literacies, among others—to prepare them for future workplaces. Among the range of new literacies, the most fundamental is cosmopolitan literacy because it entails critical, aesthetic, and empathetic skills and dispositions needed to engage with diverse values in our globalized world. In this commentary, the author discusses the principles informing cosmopolitan literacy and how it can be developed through literature.
The relationship between serum rheumatoid factor level and no‐reflow phenomenon in patients with acute ST‐segment elevation myocardial infarction undergoing primary percutaneous coronary intervention
Authors: Quisi Alaa , Alıcı Gökhan
Published: June 2018

Objective

This study aimed to evaluate the relationship between serum rheumatoid factor (RF) levels and no‐reflow phenomenon in patients with acute ST‐segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

Methods

This single‐center, cross‐sectional study included a total of 318 consecutive patients who were diagnosed with STEMI and underwent primary PCI within 12 hours of the onset of symptoms. Baseline serum RF levels of all patients were measured. The diagnosis of no‐reflow phenomenon was defined as a flow of TIMI II or less without the presence of dissection, mechanical obstruction, significant residual stenosis, or other plausible causes. The patients were divided into reflow group (n = 283) and no‐reflow group (n = 46) regarding the angiographic features of thrombolysis in myocardial infarction (TIMI) flow of the infarct‐related artery.

Results

No‐reflow phenomenon was observed in 13.8% of the patients. Median RF level was significantly higher in no‐reflow group than in reflow group (18.5 (7.0‐27.6) vs 8.0 (4.6‐50.8), P < .001). Forward conditional logistic regression analysis demonstrated that body mass index (OR = 0.845, 95% CI: 0.765 to 0.933, P = .001), diabetes mellitus (OR = 5.257, 95% CI: 1.124 to 24.587, P = .035), baseline RF level (OR = 1.198, 95% CI: 1.108 to 1.295, P < .001), and SYNTAX score I (OR = 1.065, 95% CI: 1.025 to 1.107, P = .001) were the independent predictors of no‐reflow phenomenon.

Conclusion

Baseline serum RF concentrations are independently associated with the no‐reflow phenomenon in patients undergoing primary PCI for acute STEMI.
Leucocyte telomere length and paroxysmal atrial fibrillation: A prospective cohort study and systematic review with meta‐analysis
Authors: Zhang Nixiao , Fan Chong , Gong Mengqi , Liang Xue , Zhang Weili , Li Guangping , Tse Gary , Liu Tong
Published: June 2018

Background

Telomere length is a surrogate marker of biological aging. Whether telomere length predicts the risk of atrial fibrillation (AF) independently of biological aging is controversial. We conducted a cohort study to examine the relationship between telomere length and paroxysmal AF (PAF), followed by a systematic review and meta‐analysis of the published literature, incorporating our own data.

Methods

DNA was extracted from peripheral blood. Leucocyte telomere length was measured by a real‐time polymerase chain reaction‐based method, normalized to a single copy gene, and presented as telomere/single gene ratio (t/s).

Results

A total of 100 non‐AF patients and 50 PAF patients (mean age: 61.0 ± 9.4 and 64.0 ± 10.7 years, respectively) were included. T/s for subjects without AF tended to be shorter than for those with AF (0.21 [0.06‐0.36] vs 0.28 [0.11‐0.71], P = .077). T/s was associated with a 1.60‐fold increase in the risk of AF but this was not significant (95% CI: 0.988‐2.597, P = .056). Our meta‐analysis confirms no difference in telomere length between AF and non‐AF patients and t/s was not associated with higher risk of AF in multivariate analysis.

Conclusions

Our prospective data showed that leucocyte telomere length was similar between AF and non‐AF patients but was significantly longer in male patients with PAF than those without AF in our subgroup analysis. Our meta‐analysis found that t/s did not predict AF. These findings support the notion that chronological aging, but not markers of biological aging, predicts the risk of AF.
Retracted: Zerumbone inhibits epithelial‐mesenchymal transition and cancer stem cells properties by inhibiting the β‐catenin pathway through miR‐200c
Authors: Dermani Fatemeh Karimi , Amini Razieh , Saidijam Massoud , Pourjafar Mona , Saki Sahar , Najafi Rezvan
Published: June 2018

Colorectal cancer (CRC) is one of the most lethal and rampant human malignancies in the world. Zerumbone, a sesquiterpene isolated from subtropical ginger, has been found to exhibit an antitumor effect in various cancer types. However, the effect of Zerumbone on the biological properties of CRC, including epithelial‐mesenchymal transition (EMT) and cancer stem cells (CSCs) has not been fully elucidated. Here, we investigated the inhibitory action of Zerumbone on the EMT process, CSC markers, and the β‐catenin signaling pathway in the presence or absence of miR‐200c. The effect of Zerumbone on HCT‐116 and SW‐48 cells viability was examined by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide assay. The effects of Zerumbone on EMT‐related genes, CSCs markers, cell migration, invasion, sphere‐forming, and β‐catenin signaling pathway were explored. To evaluate the role of miR‐200c in anticancer effects by Zerumbone, miR‐200c was downregulated by LNA‐anti‐miR‐200c. Zerumbone significantly inhibited cell viability, migration, invasion, and sphere‐forming potential in HCT‐116 and SW‐48 cell lines. Zerumbone significantly suppressed the EMT and CSC properties as well as downregulated the β‐catenin. Silencing of miR200c reduced the inhibitory effects of Zerumbone on EMT and CSCs in CRC cells. These data indicated that Zerumbone may be a promising candidate for reducing the risk of CRC progression by suppressing the β‐catenin pathway via miR‐200c.
Biomarker hydrogen isotope composition (δD) as proxy for Holocene hydroclimatic change and seismic activity in SW Peloponnese, Greece
Authors: Norström Elin , Katrantsiotis Christos , Finné Martin , Risberg Jan , Smittenberg Rienk H. , Bjursäter Stefan
Published: June 2018

We present a 6000‐year‐long record tracing hydroclimate changes in SW Greece, based on hydrogen isotope composition of aquatic plant‐derived n‐C23 alkanes (δDC23) in a sediment core from the Messenian plain, Peloponnese. The δDC23 record co‐varies with other eastern Mediterranean records, suggesting relatively wetter conditions c. 6–4.5 ka, followed by progressively drier conditions leading up to maximum aridity c. 2.8 ka. This arid phase was interrupted by a shift in δDC23 between 3.3 and 3.1 ka inferring wetter conditions and/or tentative responses to anthropogenic water regulating activities during the Late Bronze Age. After 2.7 ka, a return to more humid conditions was followed by increased dryness and stronger seasonality contrasts from c. 2.0 ka. The δDC23 record shows three short‐lived excursions (5.7, 5.3, 2.8 ka), where isotope values dropped by >20‰ and immediately stabilized again. The events were paralleled by abrupt increases in sedimentation rates. We hypothesize that the isotopic shifts represent a response to mixing of ground water systems during tectonic events, followed by sealing of seismically derived cracks in the active fault. The outcome of the study is promising for future expansion of isotope‐based proxies on sediments in the region, to reconstruct both hydroclimate and past seismic activity.
Basalt fibers grafted with a poly(ionic liquids) coating for in‐tube solid‐phase microextraction
Authors: Feng Juanjuan , Wang Xiuqin , Tian Yu , Luo Chuannan , Sun Min
Published: June 2018

To improve the durability and extraction efficiency of an ionic liquid coating, 1‐dodecyl‐3‐vinylimidazolium bromide was polymerized and grafted onto basalt fibers for in‐tube solid‐phase microextraction. To develop an extraction tube, basalt fibers grafted with the poly(ionic liquids) coating were filled into a polyether ether ketone tube with a 0.75 mm inner diameter. The extraction tube was connected to high‐performance liquid chromatography system equipped with a sampling pump to build an online enrichment and analysis system. Using four common phthalates as model analytes, the extraction tube was investigated by the online analysis system. Good enrichment performance was exhibited by high enrichment factors ranging from 851 to 1858. Under the optimum conditions, an online analysis method was established, and good linearity (0.03–12 and 0.15–12 μg/L) and low limits of detection (0.01–0.05 μg/L) were achieved. This analysis method was applied to real samples including water in a disposable plastic box and the bottled water, some targets were detected but not quantified, and the relative recoveries spiked at 2, 5 and 10 μg/L were in the range of 86.4–119.5%.
Movement and habitat use of headstarted Blanding's turtles in Michigan
Authors: Starking‐Szymanski Melissa D. , Yoder‐Nowak Teresa , Rybarczyk Greg , Dawson Heather A.
Published: June 2018

Captive breeding or headstarting is a management option to increase population numbers in threatened and endangered animals. The success of these programs depends on increasing population numbers while maintaining fitness within populations that contain some captive‐reared individuals. As part of an ongoing conservation project with Shiawassee National Wildlife Refuge (SNWR) in Saginaw, Michigan, USA, the Detroit Zoological Society (DZS) headstarted Blanding's turtles (Emydoidea blandingii) to 18 months of age. To determine survival, movements, and habitat use of these headstarted Blanding's turtles, we externally attached radio‐transmitters to 24 turtles and released them at 4 sites in release groups of 6 along a transect in a wetland within SNWR during June 2014. We located turtles weekly during the active season (May–Sep) and every 2 weeks during the inactive season (Oct–Apr) for 18 months, starting immediately after release and ending November 2015. We calculated straight‐line distances between release sites and home range centers over the study period. We examined habitat use of the turtles in relation to habitat availability. To predict movement of headstarted Blanding's turtles away from release sites, we used geographically weighted regression (GWR) with measured habitat factors and release sites as independent variables. There were differences in home range sizes across release groups but not between years. Headstarted juvenile Blanding's turtles in this study have home range sizes similar to those measured in other studies for wild‐hatched juveniles but smaller home ranges than those measured for wild‐hatched adults. Our study showed that headstarted Blanding's turtles used habitats with muskrat (Ondatra zibethica) dens and cattails (Typhaspp.) more than proportionally available, and used open water, willows (Salixspp.), and lowland forest less than proportionally available. The GWR model was able to predict habitat characteristics (water depth and temperature, duckweed [Lemna minor], cattails, muskrat dens and fields, buttonbush [Cephalanthus occidentalis]) that influenced the movement of turtles away from the release sites. The habitat coefficient's influence on movement varied in relation to the current location of the turtle and as habitat characteristics increased or decreased. Turtle distance from release sites decreased as water depth, water temperature, and duckweed increased, and increased as cattails, muskrat dens and fields, and buttonbush increased. Habitat in the small spatial extent at release sites may affect movement of headstarted Blanding's turtles. Furthermore, this study uses novel methodologies for assessing headstart programs that can aid future conservation and management efforts by providing information on habitat use and movement patterns of headstarted Blanding's turtles after release. © 2018 The Wildlife Society.
Cognitive overload in organizational knowledge management: Case study research
Authors: Bolisani Ettore , Scarso Enrico , Padova Antonella
Published: June 2018

The advancements in social media are producing important effects on the way organizations manage knowledge internally, because they facilitate active participation of all employees and free knowledge sharing. This can improve the capability of companies to effectively manage tacit knowledge, which has always been considered a crucial issue in the knowledge management (KM) literature. However, the impacts of social media on KM activities have only been partially analyzed. In particular, although the benefits and advantages of social media have often been emphasized, less attention has been devoted to their limitations and problems. The paper contributes to filling this gap by examining an unintended consequence of the use of social media, namely, the “cognitive overload” effect. The experience of a big consulting company that uses social media to support knowledge creation and transfer within its global communities of professionals has been analyzed. The findings of the study provide inspiration for future research and lessons for companies seeking to use social media to support innovative approaches to KM.
How Low Can You Go? Low Densities of Poly(ethylene glycol) Surfactants Attract Stealth Proteins
Authors: Seneca Senne , Simon Johanna , Weber Claudia , Ghazaryan Arthur , Ethirajan Anitha , Mailaender Volker , Morsbach Svenja , Landfester Katharina
Published: June 2018

It is now well‐established that the surface chemistry and “stealth” surface functionalities such as poly(ethylene glycol) (PEG) chains of nanocarriers play an important role to decrease unspecific protein adsorption of opsonizing proteins, to increase the enrichment of specific stealth proteins, and to prolong the circulation times of the nanocarriers. At the same time, PEG chains are used to provide colloidal stability for the nanoparticles. However, it is not clear how the chain length and density influence the unspecific and specific protein adsorption keeping at the same time the stability of the nanoparticles in a biological environment. Therefore, this study aims at characterizing the protein adsorption patterns depending on PEG chain length and density to define limits for the amount of PEG needed for a stealth effect by selective protein adsorption as well as colloidal stability during cell experiments. PEG chains are introduced using the PEGylated Lutensol AT surfactants, which allow easy modification of the nanoparticle surface. These findings indicate that a specific enrichment of stealth proteins already occurs at low PEG concentrations; for the decrease of unspecific protein adsorption and finally the colloidal stability a full surface coverage is advised.
Circular RNA circITGA7 inhibits colorectal cancer growth and metastasis by modulating the Ras pathway and upregulating transcription of its host gene ITGA7
Authors: Li Xiaomin , Wang Jianjun , Zhang Chao , Lin Chun , Zhang Jianming , Zhang Wei , Zhang Wenjuan , Lu Yanxia , Zheng Lin , Li Xuenong
Published: June 2018

Circular RNAs (circRNAs) are significantly dysregulated in various cancer types. However, the roles and mechanisms of circRNAs in cancer remain largely unknown. In this study, we demonstrated that a novel circRNA (circITGA7) and its linear host gene ITGA7 are both significantly downregulated in colorectal cancer (CRC) tissues and cell lines. These decreased expression levels correlated with CRC progression. Functional assays demonstrated that ectopic circITGA7 expression suppressed the growth and metastasis of CRC cells in vitro and in vivo. Knockdown of circITGA7 or ITGA7 promoted the proliferation and migration of CRC cells in vitro, and enhanced CRC growth in vivo. Mechanistically, by using RNA‐sequencing and KEGG enrichment analysis, we found that circITGA7 is a negative regulator of the Ras signalling pathway, and that ITGA7 is associated with cytokine‐related signalling pathways. In addition, circITGA7 binds to miR‐370‐3p to antagonise its suppression of neurofibromin 1, which is a well‐known negative regulator of the Ras pathway. Finally, circITGA7 upregulates the transcription of ITGA7 by suppressing RREB1 via the Ras pathway. In conclusion, our findings indicate a suppressor role of circITGA7 and ITGA7 in CRC, and reveal that circITGA7 inhibits the proliferation and metastasis of CRC cells by suppressing the Ras signalling pathway and promoting the transcription of ITGA7, suggesting that circITGA7 is a potential target for CRC treatment. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Calendar time as an instrumental variable in assessing the risk of heart failure with antihyperglycemic drugs
Authors: Gokhale Mugdha , Buse John B. , DeFilippo Mack Christina , Jonsson Funk Michele , Lund Jennifer , Simpson Ross J. , Stürmer Til
Published: June 2018

Objective

In recent years, second‐line diabetes treatment with dipeptidyl peptidase–4 inhibitors (DPP‐4i) increased with a corresponding decrease in thiazolidinediones (TZDs). Using hospitalization for heart failure (HF) as a positive control outcome, we explored the use of calendar time as an instrumental variable (IV) and compared this approach to an active comparator new‐user study.

Methods

We identified DPP‐4i or TZD initiators after a 6‐month washout using Medicare claims 2006–2013. The IV was defined as a binary variable comparing initiators during October 2010 to December 2013 (postperiod) versus January 2008 to May 2010 (preperiod). We examined IV strength and estimated risk differences (RDs) for HF using Kaplan‐Meier curves, which were compared with propensity score (PS)–weighted RD for DPP‐4i versus TZD.

Results

The IV compared 22 696 initiators (78% DPP‐4i) in the postperiod versus 20 283 initiators (38% DPP‐4i) in the preperiod, resulting in 40% compliance. The active‐comparator (PS‐weighted) approach compared 26 198 DPP‐4i and 18 842 TZD initiators. Covariate balance across IV levels was slightly better than across treatments (standardized difference, 3% vs 4.5%). The 1‐ and 2‐year local average treatment effects of RD of HF per 100 patients in the “compliers” (95% confidence intervals) were −0.62 (−0.99 to −0.25) and −0.88 (−1.46 to −0.25). Corresponding PS‐weighted results were −0.20 (−0.33 to −0.05) and −0.18 (−0.30 to 0.03).

Conclusion

Both approaches indicated lesser risk of HF hospitalizations among DPP‐4i vs TZD initiators. The magnitude of the estimated effects may differ due to differences in the target populations and assumptions. Calendar time can be leveraged as an IV when market dynamics lead to profound changes in treatments.
Field experience and performance analysis of floating PV technologies in the tropics
Authors: Liu Haohui , Krishna Vijay , Lun Leung Jason , Reindl Thomas , Zhao Lu
Published: June 2018

The interest in floating photovoltaic (FPV) power plants has grown rapidly in recent years. In many established and emerging markets, such as Japan, South Korea, UK, China, and India, FPV is already considered as an attractive and viable option for PV deployment. In 2016, Singapore launched the world's largest FPV testbed, with a total installed capacity close to 1 MWp. This testbed aims to study the economic and technical feasibility, as well as the environmental impacts of deploying large‐scale FPV systems on inland fresh water reservoirs. The testbed currently consists of 8 systems, with different configurations in terms of PV modules, inverters, and floating structures. The field experience of deploying, operating, and maintaining these systems, together with a comparison of their performance and reliability offers highly valuable learning points for the FPV community. In this work, we present extensive, high‐quality field measurement data; compare operating environments on water and on a rooftop; analyze system performance of different FPV systems; and share some issues encountered. We found that FPV does confer some performance benefits, but best practices should also be established to avoid new issues and pitfalls associated with deploying PV on water.
Exposure to polycyclic aromatic hydrocarbons, vitamin D, and lung function in children with asthma
Authors: Han Yueh‐Ying , Rosser Franziska , Forno Erick , Celedón Juan C.
Published: June 2018

Background

It is unclear whether exposure to polycyclic aromatic hydrocarbons (PAH) affects lung function in children with asthma. Whether vitamin D insufficiency enhances any detrimental effects of PAH on lung function in asthmatic children is also unknown.

Methods

Cross‐sectional study of 1,821 children (6‐17 years) who participated in the 2007‐2012 National Health and Nutrition Examination Survey. Multivariable linear regression was used to analyze the relation between molar mass of urinary PAH metabolites (sum of all PAH (ΣmolPAH), sum of PAH with 2 benzene rings (Σmol2‐PAH), or sum of PAH with 3 or 4 benzene rings (Σmol3,4‐PAH)) and lung function or exhaled fraction of nitric oxide (FeNO) in children with and without asthma. In this multivariable analysis, we tested whether vitamin D insufficiency (a serum 25(OH)D level <30 ng/mL) interacts with PAH exposure on lung function in children with asthma.

Results

Children in the highest quartiles of urinary Σmol3,4‐PAH had 2.3 times increased odds of asthma than those in the lowest quartile of Σmol3,4‐PAH. Urinary PAH were not associated with lung function in children with or without asthma. Given a significant interaction between vitamin D insufficiency and PAH metabolites on lung function in asthmatic children, we stratified the analysis by vitamin D status. In this analysis, urinary PAH metabolites were significantly associated with 2.7‐3.9% reduced %predicted FEV1 and %predicted FEV1/FVC in children with asthma and vitamin D insufficiency, but not in those with asthma and vitamin D sufficiency.

Conclusions

Vitamin D insufficiency and PAH exposure may have synergistic detrimental effects on lung function in asthmatic children.
Site Occupancies and Their Effects on the Physical Properties of Spinel : An Ab Initio Study
Authors: Das Debashish , Ghosh Subhradip
Published: June 2018

Recent experiments on Fe substituted spinel CoCr2O4 have discovered multiple functional properties in the system such as temperature and composition dependent magnetic compensation, and tunable exchange bias. These properties are attributed to the renormalization of the inter‐atomic magnetic exchange interactions arising due to the non‐regular site occupancies of the magnetic cations. We perform ab initio electronic structure calculations by DFT + U method and combine with a generalized thermodynamic model to compute the site occupancy patterns of magnetic cations, structural properties and magnetic exchange interactions of CoO4 for the entire composition range 0 < x < 1. We find that the substituting Fe atoms prefer to occupy the tetrahedral sites of the spinel structure for the entire range of , in agreement with the experimental inferences. By computing the variations of the various inter‐atomic magnetic exchange interactions as a function of site occupancy, we provide a microscopic picture of the evolution of a collinear structure from a non‐collinear one due to substitution of Fe in CoCr2O4. The computed results are analyzed using the electronic structures. This work is a systematic study exploring the interrelations of site occupancy, composition, electronic structure and magnetic interactions in Fe‐substituted CoCr2O4 which helps gain fundamental knowledge of this material.
All‐Optical Detection of Periodic Structure of Chalcogenide Superlattice Using Coherent Folded Acoustic Phonons
Authors: Suzuki Takara , Saito Yuta , Fons Paul , Kolobov Alexander V. , Tominaga Junji , Hase Muneaki
Published: June 2018

Chalcogenide superlattices (SL) consist of alternately stacked GeTe and Sb2Te3 layers. The structure can act as a 3D topological insulator depending on the constituent layer thicknesses, making the design of the SL period a central issue for advancing chalcogenide SL as potential candidates for spin devices as well as for optimization of the current generation of phase‐change memory devices. Here we explore the periodic structure of chalcogenide SL by observing coherent folded longitudinal acoustic (FLA) phonons excited by femtosecond laser pulse irradiation. The peak frequency of the FLA modes is observed to change upon variation of the thickness of the GeTe layer, which is well reproduced by means of an elastic continuum model. In addition, a new SL structure is unveiled for a sample consisting of thin GeTe and Sb2Te3 layers, which suggests intermixing of Ge atoms. This all‐optical technique based on observation of coherent FLA modes offers a non‐destructive characterization of superlattice structures at atomic resolution.
Ozone sensitivity of tropical upper‐troposphere and stratosphere temperature in the MetOffice Unified Model
Authors: Oh Jiyoung , Son Seok‐Woo , Williams Keith , Walters David , Kim Junsu , Willett Martin , Earnshaw Paul , Bushell Andrew , Kim Yoonjae , Kim Joowan
Published: June 2018

A systematic warm bias in the tropical tropopause layer (TTL) is commonly found in both climate and numerical weather prediction models. In this study, the nature of this temperature bias is examined by integrating the MetOffice Unified Model (MetUM) with various ozone concentrations in the TTL. Like other models, the long‐term integration of MetUM with the Atmospheric Model Intercomparison Project (AMIP) configuration shows a notable warm bias (∼2 K) in the TTL with a comparable cold bias in the tropical stratosphere above ∼70 hPa. We demonstrate that these biases are particularly sensitive to the tropical ozone concentration prescribed in the model. By replacing the background ozone, which is typically used for AMIP‐type simulations, with the Southern Hemisphere ADditional OZonesondes (SHADOZ) measurements or the Binary Data Base of Profiles (BDBP), the dipolar temperature biases in the TTL and tropical stratosphere are significantly reduced. Further sensitivity tests show that the tropical ozone amount in a 14–20 km layer is a key contributor to this change. These results suggest that accurate ozone forcing in the TTL is crucial for reliable weather and climate simulations.