bluuebunny/crossref_metadata_2025 huggingface dataset:
Examining the Relationship between Efficiency and Capital Adequacy Ratio: Islamic versus Conventional Banks --- An Empirical Evidence on Egyptian Banks
Authors: Mohamed Hafez Hassan Mohamed
Published: May 2018

This paper aims to investigate the relationship between the efficiency of banks in Egypt and capital adequacy ratios. We collected data on a sample of 40 banks comprising Islamic banks, conventional and conventional banks with Islamic windows pre and post the global financial crisis from year 2002 to 2015. We used data envelopment analysis liner programming (DEA) to calculate the efficiency of banks then we used a panel regression analysis through the application of Eviews software to investigate the relationship between the efficiency of banks and capital adequacy ratios. Pre the financial crisis, results, concluded that, there is a significant positive relationship between the efficiency of banks and capital adequacy ratios, credit risk, profitability, bank size and the quality of management. Whilst a significant negative relationship with the liquidity. The efficiency of conventional banks outperformed the efficiency of Islamic and conventional banks with Islamic windows. The increase in capital follows an increase in the level of risk borne by banks and increases capital adequacy ratios which leads to a rise in the loan portfolio and therefore, increase the level of loans provisions, which confirms the high level of efficiency for banks. Capital increase provide an additional protection against any additional risks. Post the financial crisis, the efficiency of banks has been affected especially for conventional banks. The efficiency of conventional and conventional banks with Islamic windows shows a negative significant relationship with capital adequacy ratios. The efficiency of Islamic banks outperformed other banks and shows a positive significant relationship with capital adequacy ratios. Results revealed that the efficiency of banks determines the level of capital and risk borne by banks.
Black Male Grief Through the Lens of Racialization and Oppression: Effective Instruction for Graduate Clinical Programs
Authors: Lipscomb Allen E. , Ashley Wendy
Published: May 2018

Although Black males have experienced mental health challenges analogous to other marginalized populations, Black men dealing with loss and trauma have a greater risk of experiencing severe mental health challenges than their White counterparts due to racism, classism, economic inequalities and socio-political injustices in existence since slavery. Although slavery was legally abolished in the United States in 1865, the legacy of slavery continues via systemic oppression, historical trauma and race based economic inequality. Thus, Black males’ lived experience is entrenched with elements of psychological, historical, interpersonal, and intrapsychic anguish. Black men experience grief from multiple avenues, including loss, trauma and the psychological impact of oppression. The authors explored the grief experiences of Racialized Black Men (N = 77) to identify the needs and challenges of this vulnerable population. Utilizing a Critical Race Theory (CRT) lens, recommendations are provided to educate mental health therapists both in graduate programs and as practitioners in the field regarding anti-oppressive clinical practices. Finally, effective clinical intervention practices are explored, with specific strategies for White and non-White therapists when working with this unique and often underserved population in the United States.
A Combination of Teacher-Led Assessment and Self-Assessment Drives the Learning Process in Online Master Degree in Transplantation
Authors: Halawa Ahmed , Sharma Ajay , Bridson Julie , Lyon Sarah , Prescott Denise , Guha Arpan , Taylor David
Published: May 2018

Background: Good performance in a summative assessment does not always equate to educational gain following acourse. An educational programme may focus on improving student’s performance on a particular test instrument.For example, practicing multiple choice questions may lead to mastery of the instrument itself rather than testing theknowledge and its application. We designed an assessment strategy that consistently valid and reliable that would fitwith the students with a range of 27 nationalities with a different institutional, cultural and educational background inthis totally online masters programme in transplantation.Methods: Based on the published evidence, we analyzed 2 main assessment domains: (a) self-assessment and (b)peer-assessment. We compared them with traditional teacher-led assessment considering the diversity of students.Conclusion: We conclude that traditional teacher-led assessment supplemented by self-assessment is a strong drivein the learning process in this on-line course, whilst peer-assessment is challenging and associated with many flawsgiving the diversity of our students. Peer-assessment may be unreliable and not valid due to the difference in theinstitutional background and variation in experience between the students.
African Poetry as an Expression of Agony
Authors: Chris Ajibade Adetuyi, , Adeola Adetomi Adeniran,
Published: May 2018

This study focuses on sociological study of selected African poems as an expression of agony which seeks to addressthe issues of oppression, psychological torture, injustice, apartheid, racism oppression and man’s inhumanity to manin the society. Since series of poems of culture, love, nature and animalistic voices are mostly presented by the critics,this study has as focus poetry as an expression of agony and pain in Africa.The study therefore adopted an analytic approach in its examination of the poems. The natures of agony as well assuggested resolution to this agony in the poems are pointed out with close reference to the selected poems. Poeticdevices of the two (2) poems (Nightfall in Soweto and Peasant) are also analysed in attempt to discuss the themes ofthe poems. In conclusion, it was discovered that the poems exposed the terrible state of affairs in Africa through thepoet’s effective use of symbols and images.
Roma People in Slovakia: Building a Wall Around an Ethnic Minority
Authors: Andjelic Neven
Published: May 2018

Slovakia, as multiethnic state, is home to significant Roma population making them third largest ethnic group in thecountry. Widespread discrimination in the society and inadequate state policies put many Roma in position ofunemployment, bad or no education, horrendous housing condition with no running water or electricity and otherinfrastructure, segregation and walled off communities. Europeanization of state policies might have changedlegislation but the practice is in many ways not affected.
Przedmioty lansu. O funkcjoznakach w badaniu praktyk codziennych służących autoprezentacji i budowaniu tożsamości
Authors: Rura Przemysław
Published: May 2018

In this paper I discuss the results of research on „Lans” in relation to the "tool box" provided by semiology. Particular attention I pay to constructing meanings of co-participating in the construction of identity and self-presentation. I also diagnose contemporary sign-functions. The article consists of three parts. The first part is an introduction, in which I outline the theoretical basis of research and use analysis of the semiological categories. In the second part I present fragments of research results. In the last part I undertake to explain the results and relate them to broader contexts of meaning, taking into account the multiplicity of optics and ways of interpreting sign-functions.
Polska dla Polaków, nie żaden kurwa Ahmed – analiza narracji islamofobicznych w polskim rapie
Authors: Majewski Piotr
Published: May 2018

The “invented” Muslim-migrants became contemporary “folk devils”. They are portrayed by the media – which play a crucial role in this process – as deviants, who pose a threat to the social order, national culture and values shared by all the Polish people. Thus, refugees, perceived en masse as Islamic fundamentalists, became an object of media symbolization. This mechanism allows for a mobilization against those who would like to welcome refugees to Poland – various traitors of the fatherland, lefties, liberals, post-communists or opposition politicians, who “collaborate” with the European Union and the Venice Commission. Paradoxically, the hunt for “Muslim witches” does not intend to eliminate them, but rather discursively construct them through moral panic.

The Islamophobic rap demonstrates the relationship between the Polish and the followers of Islam through binary oppositions. The Muslims and the Polish are presented as two antagonistic civilizations, although the positive connotations of this notion are rather reserved for the Polish Catholics, the sole guardians of the Christian Europe. Within this narrative the category of “Muslim” (Islamist, Arab, refugee, etc.) is essentialized, as well as the category of the “true” Polish (patriot, Catholic, heterosexual man, etc.). Anti-Muslim rappers firmly announce that if Poland decided to accept any refugees, the Polish would become a minority in their own country, stripped of their culture and faith, possibly even persecuted. They seek evidence for such extraordinary claims in the alleged transformations that other European states underwent. These radical changes are the result of an array of criminal policies introduced by the European elites, who consciously unleashed an ideological war, instrumentally utilizing Muslims as a weapon.
Usta milkły, dusza śpiewała. Wokół ostatnich nagrań Marka Grechuty
Authors: Pessel Włodzimierz Karol
Published: May 2018

In the following article the author tries to show the artistic model presented by MarekGrechuta (1945-2006) on his last music album Niezwykłemiejsca (Wondrous places), as well as various consequences of this model`s realisation. It is stressed that they were determined by singer`s psychomotor form and emotional health. Focusing on peculiar Grechuta`s case the author engages in the much wider project of anthropology of reception. It ought to explain how ambitious code of culture has collocated with pop culture over the years in Poland.
A Home on the Range and the (Near) Extinction of the American Bison
Authors: Rachwał Tadeusz
Published: May 2018

Fredreric Jackson Turner’s seminal essay on the significance of frontier in American culture interestingly posits the development of railways as extension of the buffalo trail. The presentation of his ideas in 1893 not only followed the announcement of the closing of the frontier by the superintendent of the U.S. Census (1890), but was also the time of the near-extinction of bison whose number declined from about 600,000,000 at the end of the 18th century to 300 in 1900. In the paper I will try to tone the Indian traders’ transformation of the buffalo trail into a railway with the replacement of buffalo herds by cow droves as well as the popularity the song “Home on the Range” which in a way mythologized the domestic coexistence of people with the roaming buffalo. Drawing from Thoreau’s hypothesis that cows are buffalos within and capable of reasserting their “native rights,” I will look at some examples of the return of the buffalo in the 20th and 21st centuries as, however simulated, attempts at a return to homes on the range, and at living on the frontier, even if the frontier has been relocated to the vicinity of the Fermilab bosons where a small buffalo herd is maintained.
Maude Abbott and the Origin and Mysterious Disappearance of the Canadian Medical War Museum
Authors: Wright James R. , Alberti Samuel J.M.M. , Lyons Christopher , Fraser Richard S.
Published: May 2018

Context.—

In the early 1900s, it was common practice to retain, prepare, and display instructive pathologic specimens to teach pathology to medical trainees and practitioners; these collections were called medical museums. Maude Abbott, MD, established her reputation by developing expertise in all aspects of medical museum work. She was a founder of the International Association of Medical Museums (later renamed the International Academy of Pathology) and became an internationally renowned expert on congenital heart disease. Her involvement in the Canadian Medical War Museum (CMWM) is less well known.

Objective.—

To explore Abbott's role in the development of the CMWM during and after World War I and to trace its history.

Design.—

Available primary and secondary historical sources were reviewed.

Results.—

Instructive pathologic specimens derived from Canadian soldiers dying during World War I were shipped to the Royal College of Surgeons in London, which served as a clearinghouse for museum specimens from Dominion forces. The Canadian specimens were repatriated to Canada, prepared by Abbott, and displayed at several medical meetings. Abbott, because she was a woman, could not enlist and so she reported to a series of enlisted physicians with no expertise in museology. Plans for a permanent CMWM building in Ottawa eventually failed and Abbott maintained the collection at McGill (Montreal, Quebec, Canada) until her death in 1940. We trace the CMWM after her death.

Conclusions.—

Sadly, after Abbott had meticulously prepared these precious teaching specimens so that their previous owners' ultimate sacrifice would continue to help their military brethren, the relics were bureaucratically lost.
Comparative Performance of Breast Cancer Human Epidermal Growth Factor Receptor 2 Fluorescence In Situ Hybridization and Brightfield In Situ Hybridization on College of American Pathologists Proficiency Tests
Authors: Geiersbach Katherine B. , Bridge Julia A. , Dolan Michelle , Jennings Lawrence J. , Persons Diane L. , Souers Rhona J. , Tsuchiya Karen D. , Vasalos Patricia H. , Moncur Joel T.
Published: May 2018

Context.—

Fluorescence in situ hybridization (FISH) and brightfield in situ hybridization (ISH) are 2 clinically approved laboratory methods for detecting ERBB2 (HER2) amplification in breast cancer.

Objective.—

To compare the performance of FISH and brightfield ISH on proficiency testing administered by the College of American Pathologists Laboratory Accreditation Program.

Design.—

Retrospective review was performed on 70 tissue core samples in 7 separate proficiency testing surveys conducted between 2009 and 2013.

Results.—

The samples included 13 consensus-amplified tissue cores, 53 consensus-nonamplified cores, and 4 cores that did not reach consensus for FISH and/or brightfield ISH. There were 2552 individual responses for FISH and 1871 individual responses for brightfield ISH. Consensus response rates were comparable for FISH (2474 of 2524; 98.0%) and brightfield ISH (2135 of 2189; 97.5%). The FISH analysis yielded an average HER2 copy number per cell that was significantly higher (by 2.86; P = .02) compared with brightfield ISH for amplified cores. For nonamplified cores, FISH yielded slightly, but not significantly, higher (by 0.17; P = .10) HER2 copy numbers per cell. There was no significant difference in the average HER2 to control ratio for either consensus-amplified or consensus-nonamplified cores. Participants reported “unable to analyze” more frequently for brightfield ISH (244 of 2453; 9.9%) than they did for FISH (160 of 2684; 6.0%).

Conclusions.—

Our study indicates a high concordance rate in proficiency testing surveys, with some significant differences noted in the technical performance of these assays. In borderline cases, updated American Society of Clinical Oncology/College of American Pathologists cutoff thresholds that place greater emphasis on HER2 copy number per cell could accentuate those differences between FISH and brightfield ISH.
Desempenho agronômico da soja cultivada em diferentes épocas e distribuição de plantas
Authors:   Universidade de Rio Verde, Carmo Eduardo Lima do , Braz Guilherme Braga Pereira , Simon Gustavo André , Silva Alessandro Guerra da , Rocha Antônio Germano Carpim
Published: May 2018

Períodos favoráveis à semeadura bem como a disposição espacial em que plantas se encontram na área de cultivo são fatores que influenciam diretamente a produtividade da soja. A melhor equidistância entre plantas para determinada época de cultivo pode resultar em maior aproveitamento de água, luz e nutrientes. Nesse contexto, por duas safras agrícolas de verão contínuas, foram realizados experimentos de campo com o objetivo de avaliar o desempenho agronômico da soja semeada em diferentes épocas e distribuição espacial de plantas. O delineamento utilizado foi de blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. Nas parcelas, foram alocadas quatro épocas de semeadura equidistantes de 15 dias a partir de 3 de outubro (2014/15 e 2015/16) e nas subparcelas foram dispostos, aleatoriamente, os espaçamentos entre linhas de semeadura de 0,5 e 0,25 m (tradicional e adensado, respectivamente). Na colheita, avaliaram-se características morfológicas, componentes do rendimento e a produtividade de grãos. A época de semeadura influenciou as características morfológicas e componentes do rendimento da soja. O retardamento da época de semeadura proporcionou menores rendimentos de grãos. As cultivares de soja se comportaram de maneira distinta quanto à redução no espaçamento entre linhas. A BMX Desafio RR® apresentou maior produtividade quando cultivada em espaçamento entre linhas de 0,25 m em relação ao tradicional (0,5 m).
Efeito protetor do bentazon sobre a fitotoxicidade de herbicidas inibidores de ALS em duas cultivares de feijoeiro
Authors:   Universidade do Estado de Santa Catarina, Marchioretto Lucas De Ross , Magro Taísa Dal ,   Universidade de Caxias do Sul
Published: May 2018

O presente experimento teve por objetivo avaliar a seletividade de herbicidas e o controle de plantas daninhas, na pós-emergência da cultura do feijoeiro. Foram testados os herbicidas cloransulam e imazethapyr, isoladamente e em associação com bentazon e comparados com uma testemunha capinada e uma infestada, nas cultivares de feijão Agronorte (Anfc9) e IPR Uirapuru. O experimento foi conduzido a campo, em delineamento de blocos casualizados, com quatro repetições. Foram analisadas: fitotoxidez, controle de plantas daninhas, altura de inserção de primeiro legume, número de legumes por planta, peso de mil grãos e produtividade. Cada cultivar possui nível de tolerância diferente aos herbicidas cloransulam e imazethapyr. A cultivar ANfc9 foi, em geral, mais tolerante aos herbicidas que a IPR Uirapuru. A adição de bentazon aos herbicidas cloransulam ou imazethapyr, diminui a fitotoxidez causada à cultura do feijão, cultivares Agronorte (Anfc9) e IPR Uirapuru e não altera o controle de plantas daninhas, demonstrando não haver antagonismo na mistura.
Generation of Energy from a Single Fuel Cell Using Synthesized Solid Electrolyte Membrane from Functionalized Polyisoprene/ Carbon Nanotubes
Authors: Idibie C.A. , Awatefe K.J. , Ogboru R.O.
Published: May 2018

Study on the electrical energy generated from a single fuel cell using a synthesized solid electrolyte membrane from polyisoprene that was impregnated with carbonanotubes was carried out. The initial functionalization of the polymer yielded an ion exchange capacity (IEC) of 4.04, 7.82, 11.1 and 15.53 mmol/g with their corresponding degrees of sulphonation (DS) of 10.93, 21.1, 30.03 and 42.02 %, respectively. The later but highest DS achieved water uptake of 49.23 wt % and proton conductivities of 4.3 x 10-3, 1.2 x 10-3 and 2.6 x 10-2 S/cm for membrane of thickness 250, 215 and 120 mm, respectively. The performance testing of the membrane in a single fuel cell achieved an open circuit voltage (OCV) of 647.23 mV with the synthesised membrane of 35 wt % catalyst loading, 589.79 mV and 410.48 mV of 25 wt % and 15 wt % catalyst loading, respectively at constant DS (42.02 %). Their corresponding power densities achieved were 68.67, 49.20 and 35.83 Mw/cm2, respectively. Thus the functionalization of polyisoprene impregnated with carbon nanotubes through the process of sulphonation with chlorosulphonic acid resulted into the development of solid polymer electrolyte membrane for fuel cell application.
Comparative Study on Experimental and Kerner Model Predictions of Viscoelastic Properties of Polyamide 6/ Polyvinyl Alcohol Blends
Authors: Pradeepa K.G. , Shashidhara G.M.
Published: May 2018

The Polyamide 6 (PA6) / Polyvinyl alcohol (PVOH) blends of different compositions (80/20, 60/40 and 50/50) were prepared by melt mixing in a Haake Rheomixer. The selected blend systems (80/20 and 60/40) were modified with dicumyl peroxide (DCP) and tertiary butyl cumyl peroxide (TBCP). The dynamic mechanical properties of blends were systematically investigated with special reference to the effect of blend ratio and effect of presence of peroxide over a temperature range -20°C to 110°C. The effect of change in the composition of the polymer blends on tan δ was studied to understand the damping characteristics. The mean field theory developed by Kerner has been used to estimate the dynamic properties and the estimated values are compared with the experimental values. The loss tangent curve of the blend exhibited single transition peak corresponding to the glass transition temperature (Tg) of Polyamide 6. Kerner model was found to satisfactorily predict the viscoelastic properties of the blends with polyamide content in the range 50 to 80 wt% assuming PA6 as matrix and for all compositions except 80/20 assuming PVOH as matrix. The Kerner model predictions for the selected blend systems with peroxides are not satisfactory and the co-continuous morphology of the peroxide treated blends were revealed by SEM observations.
Learning OJS 3. A Visual Guide to Open Journal Systems. Version 3.0
Authors: Public Knowledge Project The
Published: May 2018

Opdatering som dækker OJS 3.1 -Learning OJS 3.1: A Visual Guide to Open Journal Systems
CONFIGURING MATERIALITY, MOBILITY, AND MULTIACTIVITY: INTERACTIONS WITH OBJECTS IN CARS
Authors: Nevile Maurice
Published: May 2018

This paper explores how material objects feature within social interaction in the car. Objects in the car commonly include phones or other technologies, food, bags and carry items, body care products, written materials, clothing, and toys. The paper considers two examples to show how participants’ interaction with objects can be occasioned and conducted. In the first, driver spontaneously initiates involvement with the object to materially support an already-developing course of social activity (singing to passenger). In the second, driver prepares an object as a new focus of social activity with passenger (an envelope containing photos and a thank-you card). In both cases, we see especially how driver and passenger, as both vehicle occupants and social participants, organise the demands of attending to and handling objects with the dynamic demands of driving, and relative to the car’s movement in the external environment. We see how driver, in particular, embodiedly orients to objects (gaze, handling) so that driving is treated as the primary activity in a multiactivity setting. This study therefore highlights interaction in cars as a site for configuring materiality, mobility, and multiactivity. Data examples are from a corpus (27 hours, 90 journeys) of video recordings of ordinary car journeys in Australia. The language is English.
Global genomic similarity and core genome sequence diversity of the Streptococcus genus as a toolkit to identify closely related bacterial species in complex environments.
Authors: Barajas de la Torre Hugo R , Romero Miguel , Martínez-Sánchez Shamayim , Alcaraz Luis D
Published: May 2018

Background. Comparative genomics between closely related bacterial strains can distinguish important features determining pathogenesis, antibiotic resistance, and phylogenetic structure. The Streptococcus genus is relevant to public health and food safety and it is well-represented (>100 genomes) in databases of publicly available databases. Streptococci are cosmopolitan, with multiple sources of isolation, from humans to dairy products. The Streptococcus genus has been classified by morphology, serotypes, 16S rRNA gene, and Multi Locus Sequence Types (MLST). The Genomic Similarity Score (GSS) is proposed as a tool to quantify genome level relatedness between species of Streptococcus. The Streptococcus core genome can be used to assess strain specific abundances in metagenomic sequences.

Methods. A 16S rRNA gene phylogeny was calculated for 108 strains, belonging to 16 Streptococcus species and compared to a dendrogram using GSS pairwise distances for the same genomes. The core and pan-genome were calculated for these 108 genomes. The core genome sequences were analyzed and used as a resource to discriminate homologous fragment reads from closely related strains in metagenomic samples.

Results. A total of 404 proteins are shared by all 108 Streptococcus genomes, which is the core genome. The pairwise amino acid identity values of the core proteins for all the compared strains and outgroups are reported. Lower sequence identity variation (90-100%) is predominantly found in core clusters containing ribosomal and translation-related proteins. For 48 core proteins (11.8%) no functional assignment could be made and those proteins have larger sequence identity variations than other core proteins. The sequence identity of the core genome diminishes as GSS score between species decreases. The GSS dendrogram recovers most of the clades in the 16S rRNA gene phylogeny while distinguishing between 16S polytomies (unresolved nodes). Finally, the core genome was used to distinguish between closely related species within human oral metagenomes.

Discussion. The Streptococcus genus provides a benchmark dataset for comparative genomic studies due to the breath depth of genomic coverage. Comparing metagenomic shotgun fragment reads to the core genome using rapid alignment tools allows species-specific abundance estimates in metagenomic samples. Understanding of genomic variability and strains relatedness is the goal of tools like GSS, which make use of both pairwise shared core and pan-genomic homologous shared sequences for its calculation.
Low bacterial community diversity in two introduced aphid pests revealed with 16S rRNA amplicon sequencing
Authors: Zepeda-Paulo Francisca , Ortiz-Martínez Sebastían , Silva Andrea X. , Lavandero Blas
Published: May 2018

Bacterial endosymbionts that produce important phenotypic effects on their hosts are common among plant sap-sucking insects. Aphids have become a model system of insect-symbiont interactions. However, endosymbiont research has focused on a few aphid species, making it necessary to make greater efforts to other aphid species through different regions, in order to have a better understanding of the role of endosymbionts in aphids as a group. Aphid endosymbionts have frequently been studied by PCR-based techniques, using species-specific primers, nevertheless this approach may omit other non-target bacteria cohabiting a particular host species. Advances in high-throughput sequencing technologies are complementing our knowledge of microbial communities by allowing us the study of whole microbiome of different organisms. We used a 16S rRNA amplicon sequencing approach to study the microbiome of aphids in order to describe the bacterial community diversity in introduced populations of the cereal aphids, Sitobion avenae and Rhopalosiphum padi in Chile (South America). An absence of secondary endosymbionts and two common secondary endosymbionts of aphids were found in the aphids R. padi and S. avenae, respectively. Of those endosymbionts, Regiella insecticola was the dominant secondary endosymbiont among the aphid samples. In addition, the presence of a previously unidentified bacterial species closely related to a phytopathogenic Pseudomonad species was detected. We discuss these results in relation to the bacterial endosymbiont diversity found in other regions of the native and introduced range of S. avenae and R. padi. A similar endosymbiont diversity has been reported for both aphid species in their native range. However, variation in the secondary endosymbiont infection could be observed among the introduced and native populations of the aphid S. avenae, indicating that aphid-endosymbiont associations can vary across the geographic range of an aphid species. In addition, we discuss the potential role of aphids as vectors and/or alternative hosts of phytopathogenic bacteria.
Screening of polyhydroxyalkanoate-producing bacteria and PhaC-encoding genes in two hypersaline microbial mats from Guerrero Negro, Baja California Sur, Mexico
Authors: Martínez-Gutiérrez Carolina A. , Latisnere-Barragán Hever , García-Maldonado José Q. , López-Cortés Alejandro
Published: May 2018

Hypersaline microbial mats develop through seasonal and diel fluctuations, as well as under several physicochemical variables. Hence, resident microorganisms commonly employ strategies such as the synthesis of polyhydroxyalkanoates (PHAs) in order to resist changing and stressful conditions. However, the knowledge of bacterial PHA production in hypersaline microbial mats has been limited to date, particularly in regard to medium-chain length PHAs (mcl-PHAs), which have biotechnological applications due to their plastic properties. The aim of this study was to obtain evidence for PHA production in two hypersaline microbial mats of Guerrero Negro, Mexico by searching for PHA granules and PHA synthase genes in isolated bacterial strains and environmental samples. Six PHA-producing strains were identified by 16S rRNA gene sequencing; three of them corresponded to aHalomonassp. In addition,Paracoccussp.,Planomicrobiumsp. andStaphylococcussp. were also identified as PHA producers. Presumptive PHA granules and PHA synthases genes were detected in both sampling sites. Moreover, phylogenetic analysis showed that most of the phylotypes were distantly related to putative PhaC synthases class I sequences belonging to members of the classes Alphaproteobacteria and Gammaproteobacteria distributed within eight families, with higher abundances corresponding mainly to Rhodobacteraceae and Rhodospirillaceae. This analysis also showed that PhaC synthases class II sequences were closely related to those ofPseudomonas putida, suggesting the presence of this group, which is probably involved in the production of mcl-PHA in the mats. According to our state of knowledge, this study reports for the first time the occurrence ofphaCandphaC1sequences in hypersaline microbial mats, suggesting that these ecosystems may be a novel source for the isolation of short- and medium-chain length PHA producers.
In Vitro Microscale Models for Embryogenesis
Authors: Rico‐Varela Jennifer , Ho Dominic , Wan Leo Q.
Published: May 2018

Embryogenesis is a highly regulated developmental process requiring complex mechanical and biochemical microenvironments to give rise to a fully developed and functional embryo. Significant efforts are taken to recapitulate specific features of embryogenesis by presenting the cells with developmentally relevant signals. The outcomes, however, are limited partly due to the complexity of this biological process. Microtechnologies such as micropatterned and microfluidic systems, along with new emerging embryonic stem cell‐based models, can potentially serve as powerful tools to study embryogenesis. The aim of this article is to review major studies involving the culturing of pluripotent stem cells using different geometrical patterns, microfluidic platforms, and embryo/embryoid body‐on‐a‐chip modalities. Indeed, new research opportunities have emerged for establishing in vitro culture for studying human embryogenesis and for high‐throughput pharmacological testing platforms and disease models to prevent defects in early stages of human development.
O Phase Precipitation and Variant Selection in Ti–22Al–25Nb Alloy during the Hot Shear Spinning
Authors: Wu Yang , Kou Hongchao , Tang Bin , Liu Degui , Li Jizhen , Li Jinshan
Published: May 2018

O phase precipitation and variant selection in Ti–22Al–25Nb alloy during the hot shear spinning are investigated using scanning electron microscope (SEM), electron backscattered second diffraction (EBSD), and transmission electron microscope (TEM). The results show that the random O phase precipitates from the B2 matrix during the hot shear spinning. With the increase of reduction ratio, the average thickness of O precipitates increases from ≈0.18 to ≈0.50 μm. Meanwhile, the O precipitates show various morphologies, including lamella, short rod, and sphere. Twelve O variants simultaneously form in the parent B2 phase and the orientation relationship between the B2–O phases is confirmed as [−111] B2//[1–10] O and (110) B2//(001) O. Different patterns of dislocation are also found in the B2 matrix, such as dislocation tangles, dislocation nets, and dislocation arrays. They play an important role in the variant selection of O precipitates, resulting in the different angled combinations of O variants. In addition, massive dislocation piles up along the O/B2 interface and some dislocation wall generates within the O phase, which are benefit for the globularization of O precipitates.
A Strategy for Architecture Design of Crystalline Perovskite Light‐Emitting Diodes with High Performance
Authors: Shi Yifei , Wu Wen , Dong Hua , Li Guangru , Xi Kai , Divitini Giorgio , Ran Chenxin , Yuan Fang , Zhang Min , Jiao Bo , Hou Xun , Wu Zhaoxin
Published: May 2018

All present designs of perovskite light‐emitting diodes (PeLEDs) stem from polymer light‐emitting diodes (PLEDs) or perovskite solar cells. The optimal structure of PeLEDs can be predicted to differ from PLEDs due to the different fluorescence dynamics and crystallization between perovskite and polymer. Herein, a new design strategy and conception is introduced, “insulator–perovskite–insulator” (IPI) architecture tailored to PeLEDs. As examples of FAPbBr3 and MAPbBr3, it is experimentally shown that the IPI structure effectively induces charge carriers into perovskite crystals, blocks leakage currents via pinholes in the perovskite film, and avoids exciton quenching simultaneously. Consequently, as for FAPbBr3, a 30‐fold enhancement in the current efficiency of IPI‐structured PeLEDs compared to a control device with poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) as hole‐injection layer is achieved—from 0.64 to 20.3 cd A−1—while the external quantum efficiency is increased from 0.174% to 5.53%. As the example of CsPbBr3, compared with the control device, both current efficiency and lifetime of IPI‐structured PeLEDs are improved from 1.42 and 4 h to 9.86 cd A−1 and 96 h. This IPI architecture represents a novel strategy for the design of light‐emitting didoes based on various perovskites with high efficiencies and stabilities.
Few‐Layer Silicene Nanosheets with Superior Lithium‐Storage Properties
Authors: Liu Jingjing , Yang Yang , Lyu Pengbo , Nachtigall Petr , Xu Yuxi
Published: May 2018

Silicene, a 2D silicon allotrope with unique low‐buckled structure, has attracted increasing attention in recent years due to its many superior properties. So far, epitaxial growth is one of the very limited ways to obtain high‐quality silicene, which severely impedes the research and application of silicene. Therefore, large‐scale synthesis of silicene is a great challenge, yet urgently desired. Herein, the first scalable preparation of free‐standing high‐quality silicene nanosheets via liquid oxidation and exfoliation of CaSi2 is reported. This new synthesis strategy successfully induces mild oxidation of the (Si2n)2n− layers in CaSi2 into neutral Si2n layers without damage of pristine silicene structure and promotes the exfoliation of stacked silicene layers. The obtained silicene sheets are dispersible and ultrathin ones with monolayer or few‐layer thickness and exhibit excellent crystallinity. As a unique 2D layered silicon allotrope, the silicene nanosheets are further explored as new anodes for lithium‐ion batteries and exhibit a nearly theoretical capacity of 721 mAh g−1 at 0.1 A g−1 and an extraordinary cycling stability with no capacity decay after 1800 cycles in contrast to previous most silicon anodes showing rapid capacity decay, thus holding great promise for energy storage and beyond.
Phase Manipulation of Electromagnetic Waves with Metasurfaces and Its Applications in Nanophotonics
Authors: Chen Shuqi , Li Zhi , Zhang Yuebian , Cheng Hua , Tian Jianguo
Published: May 2018

Relative to conventional phase‐modulation optical elements, metasurfaces (i.e., 2D versions of metamaterials) have shown novel optical phenomena and promising functionalities with more compact platforms and more straightforward fabrication processes. With the ability to generate a spatial phase variation, optical wavefronts can be manipulated into arbitrary shapes at will, enabling new phenomena and integrated ultrathin optical devices to be explored. This review is focused on recent developments regarding phase manipulation of electromagnetic waves with metasurfaces. Starting from their underlying physics for realizing full 2π phase manipulation, an overview of the applications of such metasurfaces in nanophotonics is discussed, concluding with a discussion of future prospects in this field.
Multifunctional Hybrid Metasurfaces for Dynamic Tuning of Terahertz Waves
Authors: Cai Honglei , Chen Shi , Zou Chongwen , Huang Qiuping , Liu Yu , Hu Xiang , Fu Zhengping , Zhao Yi , He Hongchuan , Lu Yalin
Published: May 2018

Actively tuning optical transmission through hybrid metasurfaces incorporated with multifunctional active media holds great promise for the next generation optical devices. In the terahertz (THz) range, they remain rare due to the lack of dynamic and multifunctional designs and materials. Here, a vanadium dioxide (VO2)‐based hybrid metasurface is proposed to present multifunctional control of THz waves via electrically triggering and ultrafast optical excitation. By minimizing the thermal mass of VO2 and optimizing the VO2 patterns within two side gaps of the asymmetric split‐ring resonators, a hybrid metasurface which can tune the THz wave with an absolute modulation depth up to 54% and a figure of merit as high as 138% is hereby presented. The hybrid metasurface achieves a switching time of 2.2 s under the electrically triggering and offers an ultrafast modulation within 30 ps under the femtosecond pulse excitation. More interestingly, owing to the intrinsic hysteresis behavior of VO2, the hybrid metasurface exhibits distinguishing multistate transmission amplitudes with a single electrical input. In short, this study paves the way for robust multifunctionality in electric‐controlled terahertz switching, photonic memory, and ultrafast terahertz optics.
A Highly Sensitive UV–vis–NIR All‐Inorganic Perovskite Quantum Dot Phototransistor Based on a Layered Heterojunction
Authors: Zou Chen , Xi Yuyin , Huang Chun‐Ying , Keeler Ethan G. , Feng Tianyu , Zhu Shihao , Pozzo Lilo D. , Lin Lih Y.
Published: May 2018

All‐inorganic perovskite quantum dots (IPQDs) are a promising material for use in various optoelectronic devices due to their excellent optoelectronic properties and high environmental stability. Here, a high‐performance phototransistor based on a layered heterojunction composed of CsPbI3 QDs and a narrow‐bandgap conjugated polymer DPP‐DTT is reported, which shows a high responsivity of 110 A W−1, a specific detectivity of 2.9 × 1013 Jones and a light to dark current ratio up to 6 × 103. The heterojunction phototransistor exhibits unipolar p‐type and gate bias modulated behaviors. In addition, the device exhibits a broad spectral detection range from ultraviolet to near infrared. The high sensitivity of the device is attributed to the layered heterojunction and the gate bias modulation property. The work overcomes the existing limitations in sensitivity of IPQD photodetectors due to the poor charge transport between QDs. The convenient solution‐processed fabrication and excellent device performance especially suggest the IPQD/narrow‐bandgap conjugate polymer heterojunction as a promising structure for potential applications of ultrasensitive broadband photodetectors compatible with a wide variety of substrates.
Large‐Area Tunable Visible‐to‐Near‐Infrared Luminescent Solar Concentrators
Authors: Correia Sandra F. H. , Frias Ana R. , Fu Lianshe , Rondão Raquel , Pecoraro Edison , Ribeiro Sidney J. L. , André Paulo S. , Ferreira Rute A. S. , Carlos Luís D.
Published: May 2018

Luminescent solar concentrators (LSCs) appear as an intriguing way to cope with the limitation of the mismatch between the photovoltaic (PV) cells response and the solar spectrum, with the additional advantage of facilitating urban integration of photovoltaics. A new LSCs geometry based on triangular hollow‐core plastic optical fibers (POFs) filled with organic–inorganic hybrid materials doped with Rhodamine 6G, Rhodamine 800, or an Europium β‐diketonate complex is presented. Large‐area LSCs are built from POFs bundle structures, whose assembling is favored by the fiber triangular cross section that also maximizes the coverage of a PV cell surface compared with cylindrical POFs. Each bundle fiber behaves as an individual LSC absorbing UV/blue components of the solar spectrum and emitting visible/NIR radiation. The LSCs are characterized by optical conversion efficiency values up to ηopt ≈5.3%, among the largest values reported for single‐layer LSCs. Moreover, the coupling between the LSCs to commercial Si PV cells yields maximum power conversion efficiency values of PCE ≈0.74%. The individual waveguiding features of each fiber in the bundle contribute to reduce the reabsorption, as lower performance values (ηopt ≈1.5%; PCE ≈0.09%) are estimated for a planar LSC with analogous surface collection area and light‐harvesting absorbance.
Conversion of Iron Ore into an Active Catalyst for the Oxygen Evolution Reaction
Authors: Sayeed Md Abu , Fernando Joseph F. S. , O'Mullane Anthony P.
Published: May 2018

The storage of electricity from intermittent renewable energy sources in the form of hydrogen via water electrolysis is an attractive approach to reducing CO2 levels, as well as powering future transportation with hydrogen fuel cells. Earth‐abundant transition metal oxide like materials are synthesized and extensively studied in research laboratories to replace expensive IrO2 and RuO2 anodes for the oxygen evolution half reaction. However, pristine materials mined from the earth's crust are yet to be explored for such an application. Here the electrocatalytic activity of iron ore is investigated and a novel approach is reported to significantly improve its catalytic properties via formation of a nickel hydroxide layer on the surface. This electrocatalyst achieves a current density of 10 mA cm−2 at a low overpotential of 280 mV and maintains its activity for extended periods of electrolysis under alkaline conditions. This simple process to convert an abundant commodity into a value‐added product should be of considerable interest.
An Ultrahigh Capacity Graphite/Li2S Battery with Holey‐Li2S Nanoarchitectures
Authors: Ye Fangmin , Noh Hyungjun , Lee Hongkyung , Kim Hee‐Tak
Published: May 2018

The pairing of high‐capacity Li2S cathode (1166 mAh g−1) and lithium‐free anode (LFA) provides an unparalleled potential in developing safe and energy‐dense next‐generation secondary batteries. However, the low utilization of the Li2S cathode and the lack of electrolytes compatible to both electrodes are impeding the development. Here, a novel graphite/Li2S battery system, which features a self‐assembled, holey‐Li2S nanoarchitecture and a stable solid electrolyte interface (SEI) on the graphite electrode, is reported. The holey structure on Li2S is beneficial in decomposing Li2S at the first charging process due to the enhanced Li ion extraction and transfer from the Li2S to the electrolyte. In addition, the concentrated dioxolane (DOL)‐rich electrolyte designed lowers the irreversible capacity loss for SEI formation. By using the combined strategies, the graphite/holey‐Li2S battery delivers an ultrahigh discharge capacity of 810 mAh g−1 at 0.1 C (based on the mass of Li2S) and of 714 mAh g−1 at 0.2 C. Moreover, it exhibits a reversible capacity of 300 mAh g−1 after a record lifecycle of 600 cycles at 1 C. These results suggest the great potential of the designed LFA/holey‐Li2S batteries for practical use.
Bifunctional Nitrogen and Cobalt Codoped Hollow Carbon for Electrochemical Syngas Production
Authors: Song Xiaokai , Zhang Hao , Yang Yuqi , Zhang Bin , Zuo Ming , Cao Xin , Sun Jianhua , Lin Chao , Li Xiaopeng , Jiang Zheng
Published: May 2018

Electrochemical conversion of CO2 and H2O into syngas is an attractive route to utilize green electricity. A competitive system economy demands development of cost‐effective electrocatalyst with dual active sites for CO2 reduction reaction (CO2RR) and hydrogen evolution reaction (HER). Here, a single atom electrocatalyst derived from a metal–organic framework is proposed, in which Co single atoms and N functional groups function as atomic CO2RR and HER active sites, respectively. The synthesis method is based on pyrolysis of ZnO@ZIF (zeolitic imidazolate framework). The excess in situ Zn evaporation effectively prevents Co single atoms (≈3.4 wt%) from aggregation and maintains appropriate Co/N ratio. The as‐prepared electrocatalyst is featured with high graphitic degree of carbon support for rapid electron transport and sponge‐like thin carbon shells with hierarchical pore system for facilitating active site exposure and mass transport. Therefore, the electrocatalyst exhibits a nearly 100% Faradic efficiency and a high formation rate of ≈425 mmol g−1 h−1 at 1.0 V with the gaseous product ratio (CO/H2) approximating ideal 1/2. With the assistance of an extensive material characterization and density functional theory (DFT) calculations, it is identified that Co single atoms are uniformly coordinated in the form of Co–C2N2 moieties, and act as the major catalytic sites for CO2 reduction.
Fabrication of Sub‐Micrometer‐Thick Solid Electrolyte Membranes of β‐Li3PS4 via Tiled Assembly of Nanoscale, Plate‐Like Building Blocks
Authors: Hood Zachary D. , Wang Hui , Pandian Amaresh Samuthira , Peng Rui , Gilroy Kyle D. , Chi Miaofang , Liang Chengdu , Xia Younan
Published: May 2018

Solid electrolytes represent a critical component in future batteries that provide higher energy and power densities than the current lithium‐ion batteries. The potential of using ultrathin films is among the best merits of solid electrolytes for considerably reducing the weight and volume of each battery unit, thereby significantly enhancing the energy density. However, it is challenging to fabricate ultrathin membranes of solid electrolytes using the conventional techniques. Here, a new strategy is reported for fabricating sub‐micrometer‐thick membranes of β‐Li3PS4 solid electrolytes via tiled assembly of shape‐controlled, nanoscale building blocks. This strategy relies on facile, low‐cost, solution‐based chemistry to create membranes with tunable thicknesses. The ultrathin membranes of β‐Li3PS4 show desirable ionic conductivity and necessary compatibility with metallic lithium anodes. The results of this study also highlight a viable strategy for creating ultrathin, dense solid electrolytes with high ionic conductivities for the next‐generation energy storage and conversion systems.