bluuebunny/crossref_metadata_2025 huggingface dataset:
Saúde e Doença: A Resistência Médica durante a Ditadura Militar na Revista Saúde em Debate (1977)
Authors: Mendes de Paula Éder
Published: May 2020

O presente artigo intenciona compreender a relação construída durante a ditadura militar entre os níveis de pobreza que assolavam a população e as implicações deste fenômeno no tocante ao acesso e prestação dos serviços de saúde, bem como a disseminação de patologias nas camadas mais populares. Esse estudo torna-se possível pela leitura e análise da Revista Saúde em Debate publicada no trimestre de Julho-Setembro de 1977. O periódico era organizado pelo Centro Brasileiro de Estudos de Saúde (Cebes). Os editoriais repletos de estudos que visavam problematizar questões sociais impactadas pelo contexto histórico daquele período, fomentavam mudanças na sociedade e auxiliam na compreensão do imaginário sobre a Saúde Pública durante o Regime Militar no Brasil.
O Ato Institucional nº 2: lutas judiciais, imprensa e divergências na ditadura civil-militar (1964-1965)
Authors: Gamba Torres Mateus
Published: May 2020

O ato institucional nº 2 trouxe para a ordem política e jurídica brasileira no período da ditadura uma série de mudanças que vão muito além da extinção dos partidos políticos. O presente artigo trata dos debates em diversos jornais de 1964 e 1965 sobre as propostas que ao final foram impostas a sociedade pelo segundo ato institucional. Tais propostas já vinham sendo lançadas e debatidas pela imprensa e intelectuais, antes de serem autoritariamente colocadas no ordenamento jurídico brasileiros. Tanto que durante 1964 e 1965, juristas de renome e os próprios ministros do Supremo Tribunal Federal entrarão em conflito com a ditadura, contrários às propostas de castelo que modificariam a constituição e restringiriam seu poderes, mas que ao final tiveram que aceitar e conviver com elas.
Factors Affecting Investment Decision in the Saudi Stock Market
Authors: Alhussain Meshari
Published: May 2020

This research aims to explore the factors influencing the decision of investment in the Saudi Arabian stock market which are the following factors: the analysis and financial ratios, the history and reputation of the company, dividends, date of the company’s founding, company size, recommendations and opinions of analysts, the nature of the company's activity) and its impact on investment decision. A questionnaire has been used as a research tool, the study group consisted of all individuals investing in the Saudi stock market in 2018, and the sample was selected in an available way which is one type of non-random sample, with a total of 128 valid questionnaires for analysis out of 130 questionnaires. The research on its theoretical side touched on the efficiency and importance of the market, the types of financial markets, the formation and evolution of the Saudi stock market, the period of collapse of the Saudi stock market, the post-collapse Saudi stock market. While the tests of reliability and stability (Cronbach's alpha coefficient), frequencies, percentages, arithmetic averages and standard deviation, (T- test) for differences between two independent samples (independent sample T-test), one-way analysis of variance (one-way ANOVA) were used in the practical aspect of the research. The research has found an effect of the following factors: analysis and financial ratios, the history and reputation of the company, dividends, date of the company’s founding, company size, recommendations and opinions of analysts, the nature of the company's activity) on investment decision.The most influential factor on investment decision is the analysis and financial ratios, followed by the reputation and history of the company, dividends and its impact on investment decision ranked third, while date of the company’s founding ranked fourth in terms of influencing investment decision, while the nature of the company's activity ranked fifth in terms of impact, followed by company size in the sixth rank, and finally recommendations and opinions of analysts ranked seventh and last in terms of influencing the decision of investment in the Saudi stock market.
Evaluating self-efficacy and personality differences of nursing students in clinical simulation
Authors: McIntosh Constance E. , Hernandez-Finch Maria E. , Thomas Cynthia M. , Finch W. Holmes , Hulse Asia R. , Brelage Pamela K. , McIntosh David E.
Published: May 2020

Background: This present research was conducted to evaluate the efficacy of a clinical simulation where senior nursing students cared for a standardized patient with Autism Spectrum Disorder (ASD). The goal of the simulation was to teach the nursing students how to work with children with autism. In addition, the study aimed to determine if individual differences in personality affect students’ abilities to complete the simulation and how a student’s personality may affect their perceptions of the simulation. Projected outcomes included learning the use of appropriate communication strategies, improved assessment skills, prioritization of care, development of problem-solving skills, and decision-making abilities when dealing with children with ASD.Methods: Simulations are verified as effective training mechanisms to increase students’ self-efficacy in multiple nursing settings. Therefore, seventy-five senior baccalaureate nursing students completed the standardized patient simulation for care of an individual with ASD. The effect on the students’ self-efficacy was measured using the Occupational and Academic Self-Efficacy for Nursing Measure, the IPEP-NEO short form, and an ASD simulation study questionnaire.Results and conclusions: Logistic regression was used to investigate the relationship between personality measures and experience with ASD. The higher the openness and extraversion scores the more likely respondents were to disclose positive benefits in relation to expectations, communication strategies, teamwork, and reflection.
To Find Accident Prone Zones and Nearest Health Facility by GIS Based Spatial and Network Analysis in Amritsar, Punjab
Authors: Chaudary Jatin , Mishra Vishal , Jain Bhavna , Akshay S , Reddy D Shivaram , Kaduluri Pridhvi Gangireddy
Published: May 2020

Context: The use of Geographic Information System (GIS) as a real-time monitoring system for the control and management of accident events is well known as it provides a platform to perform various spatial and network analysis and also in the presentation of descriptive data.

Aim and Objective: This paper presents a GIS-based approach to find out areas prone to road traffic accidents based on spatial analysis and to analyze the spatial accessibility using network analysis

Material and Methods Accident particulars like date, location, time and outcome for the year 2015 were included in the GIS database. Moran’s I method of spatial autocorrelation was used for the assessment of spatial clustering of accidents and hotspots spatial densities. The clusters of high and low values of the severity of accidents were obtained using cluster and outlier analysis. Location-allocation was performed as part of network analysis to find the nearest hospital to these high-value clusters.

Results: Spatial autocorrelation showed that there was overall clustering present, cluster and outlier analysis gave clusters of severe accidents at NH-1 and Fortis hospital was the nearest facility to these clusters.

Conclusion: This system is highly useful and provides information about accident locations, accident and service diagnosis and fast delivery of emergency services.
Evaluation of New born Stabilization Units in the Health Facilities in Uttarakhand, India
Authors: Sharma Anusha , Khapre Meenakshi , Kishore Surekha
Published: May 2020

Background: Our country is adding to one-fifth of live births globally and an enormous number of neonatal deaths (<25%). In India, although the number of new-born stabilization units (NBSU) reported operational is increasing but there is lack of clarity of the role of NBSUs as well as suboptimal utilization and quality of services in these units.

Material and method: A cross-sectional study was conducted from December 2017 to Jan 2018 in health facilities with functioning NBSUs in three blocks of Haridwar and two blocks in Tehri.

Results: Out of total 2602 deliveries, 221 neonatal admissions were reported with an average length of stay at the hospital in most of the centres was one and a half-day. There were a limited number of trained doctors and nurses in the health facilities. The maximum deficit was found with the availability of resuscitator and oxygen cylinder (80%) followed by a digital thermometer (75%).

Conclusion: To ensure essential care to the new-borns by keeping quality at the centre it is important to focus upon adequate number of medical staff, properly functioning equipment, continuous supply of medicines, regular training sessions and appropriate referral mechanism to higher centres.
Examining the Relationship Between School Mindfulness and Organizational Trust
Authors: Tabancalı Erkan , Öngel Gülay
Published: May 2020

The purpose of the study is to investigate the relationship between organizational trust and school mindfulness. To achieve this purpose, a quantitative approach and relational design were preferred, and School Mindfulness Scale and Organizational Trust Scale were used as data collection tools. The study sample consisted of 495 participants working in public schools in İstanbul province. The data was evaluated using arithmetic mean, correlation and regression analysis. According to the results, trust in the principal and colleagues improves school mindfulness. Furthermore, trust in the principal increases the mindfulness of the school principal, while trust in colleagues enhances mindfulness among the faculty. It can therefore be said that school principals may prefer to strengthen organizational trust to increase the level of mindfulness within the school.
Examining the Scientific Argumentation Implemented Through a Social Constructivism-Based Curriculum Designed for Primary Science Education in a Confucian Heritage Culture: A Case Study in Vietnam
Authors: Hằng Ngô Vũ Thu , Bulte Astrid M.W. , Pilot Albert
Published: May 2020

This study describes the improvement of a science curriculum based on a social constructivist approach in order to support primary students in a Confucian heritage culture in practicing scientific argumentation. The former design is adjusted by the application of an adapted model of the learning placemat for argumentation and by the formulation of concrete teaching-learning activities which are articulated with the application of the adapted learning placemat. The practice of a designed curriculum unit reveals that the designed curriculum can support the primary students in practicing scientific argumentation and in attaining consensually agreed knowledge. Nevertheless, the study also shows that primary teachers and students in a Confucian heritage culture do not pay much attention to the activities of qualifying and rebutting in scientific argumentation. The study recommends that further developmental research needs to deal with the refined problem of how to improve qualifying and rebutting in scientific argumentation in the practice of science lessons in a Confucian heritage culture.
Quality Education Accreditation of the United States and Vietnam's Management Model
Authors: Hanh Nguyen Duc
Published: May 2020

Accreditation is a solution for improving the quality of education in higher education institutions. Quality accreditation plays a dominant role that supports quality assurance management in the higher education system. The accreditation frameworks and external quality assurance are different between countries. The United States started quality accreditation very early, so it has a robust educational quality accreditation system, excellent support for the development of higher education institutions. Vietnam has only begun to conduct quality accreditation in recent years. At present, there are still some differences between Vietnam and the United States in quality management activities, but education quality accreditation of Vietnam is approximately similar the United States and carried out in three models: the model of central control of quality assurance of state; model of quality assurance combining between state control with the market competition; and model in which the state primarily leave responsibility for quality assurance to self-accrediting universities.
Women’s expectations and preferences for care of the newborn in the immediate postpartum period
Authors: Kremska Anna , Zych Barbara , Wróbel Romana , Kraśnianin Elżbieta , Jeżowska Malwina
Published: May 2020

Background: The Regulation of the Minister of Health issued on 16th August 2018 addressed the matter of the organizational standard of perinatal care which determines guidelines concerning care of the newborn baby, in which skin-to-skin contact and early breastfeeding are important.
Aim of the study: The aim of this study is to explore women's preferences concerning care of the newborn in the immediate postpartum period.
Material and methods: 130 patients attending the Pro-Familia specialist hospital in Rzeszow participated in this research. The cohort consisted of pregnant women who had attended the doctor supervising their pregnancy before delivery. The research was carried out from March to April 2013 and the data collected was statistically analyzed, assuming a significance level of p<0.05.
Results: Pregnant women most often expressed a preference of an accompanying person to cut the newborn’s umbilical cord (59.2%), with 23.1% preferring a member of the medical team to do so. The majority (89.2%) of pregnant women wanted their baby to be laid on their stomach immediately following delivery to ensure skin-to-skin contact. In terms of Apgar scoring, 69.2% of women expected information about the Apgar score of their newborn immediately after delivery. Most women (60%) wished their newborn to be given routine vaccinations for hepatitis B and tuberculosis (BCG). Patients most often declare that they want to breastfeed exclusively (77.7%), with 29.2% of women expressing a wish to obtain more information about breastfeeding and 31.5% wishing to consult with a lactation specialist.
Conclusions: Pregnant women expect skin-to-skin contact immediately after delivery, the umbilical cord to be cut by an accompanying person and would like to be told their newborn’s Apgar score. The women studied prefer exclusively breastfeeding, and express a wish to obtain information regarding lactation, and expect to be able to consult with a lactation specialist.
DAS CINZAS À PURPURINA: bichas que cintilam em leitura e escrita biografemática
Authors: Pereira Tales Santos , Mitidieri André Luis
Published: May 2020

Pela perspectiva biografemática, conforme proposição de Roland Barthes (1990), propomos uma leitura homoerótica da narrativa jornalística de cunho biográfico “Manuel nunca dijo adiós”, de Tomás Eloy Martínez, e do roteiro cinematográfico La tajada, de Manuel Puig, a fim de flagrar vestígios e pormenores de identidades e subjetividades homoeroticamente inclinadas. Dessa forma, os biografemas revelados, em cenas de flertes, paqueras, flashs da infância e memórias de grandes ícones, constituem-se enquanto espaço de discussão das representações da dissidência sexual e da multiplicidade de agenciamentos, modos de ler, ser, viver e interpretar o mundo.
MULTIPLICIDADE E PLURISSIGNIFICAÇÃO: O VERMELHO MULTICOR DE HELENA PARENTE CUNHA
Authors: Souto Andrea Do Roccio
Published: May 2020

Nesse estudo, a partir da proposta de leitura analítica e interpretativa de Sérgio Farina, analisa-se As doze cores do vermelho, de Helena Parente Cunha. Publicada originalmente em 1989, a obra busca desconstruir o discurso homogêneo da cultura patriarcalista hegemônica, discutir questões relacionadas à mulher em nossa sociedade, repensar o caráter da produção literária feminina e construir discursos em que a mulher seja vista como sujeito.
Invisibilidade? A potência do não-ser: resistência e memória em Com armas sonolentas, de Carola Saavedra
Authors: Vivian Ilse Maria Da Rosa
Published: May 2020

A poética de Com armas sonolentas aponta dois sentidos emergenciais: a resistência e a memória. O romance é a história de quatro mulheres que, em meio aos silenciamentos e às violências, encontram nas fissuras da realidade hierarquizante e heteronormativa o caminho para desvelar suas identidades. Objetiva-se evidenciar, a partir da noção de resistência (Agamben, 2018), as opções de construção do discurso que culmina com a proposição de uma antimemória. Não ser é a primeira arma para resistir à invisibilidade do eu produzida pelo outro. Na contramão da hegemonia do conhecimento, da razão, revela-se a sabedoria de uma memória em devir.
Escrita e performance na poesia de autoria feminina contemporânea
Authors: Pavani Cinara
Published: May 2020

A poesia de autoria feminina produzida a partir da segunda metade do século XX no Brasil destaca-se por seu caráter performático, na medida em que propõe a encenação do feminino e seu universo íntimo, assim como a dramatização de problemas relacionados às políticas de gênero. Levando em consideração estudos sobre escrita e performance, em especial de Roland Barthes e Graciela Ravetti, propõe-se a análise da poesia de autoras contemporâneas, com vistas a examinar sua performatividade e a repercussão dessa característica nos debates atuais sobre gênero.
“A distopia de ontem é a realidade de hoje”: uma entrevista com Susana Bornéo Funck
Authors: Bornéo Funck Susana , Alós Anselmo
Published: May 2020

Nesta entrevista, o professor Anselmo Peres Alós conversa com Susana Bornéo Funck, professora aposentada de Literaturas de Língua Inglesa da Universidade federal de Santa Catarina. Susana possui uma longa trajetória como docente e pesquisadora, sendo um dos nomes de destaque no cenário da crítica literária feminista no Brasil. Ao longo da entrevista, Susana fala de sua formação, de sua trajetória como docente e como pesquisadora universitária, do início da crítica feminista no Brasil, da institucionalização da pesquisa feminista na academia brasileira
OS BENEFICIÁRIOS DO PROGRAMA BOLSA FAMÍLIA E O MERCADO DE TRABALHO: UMA ANÁLISE SOBRE O “EFEITO PREGUIÇA”
Authors: Prosperi Luciene Oliveira , Frias Lincoln
Published: May 2020

Uma das críticas recorrentes ao Programa Bolsa Família (PBF) é o receio de que os beneficiários trabalhem menos do que trabalhariam se não recebessem a transferência de renda, o chamado “efeito preguiça”. Este artigo é uma revisão bibliográfica sobre esse assunto. Após a introdução, a segunda seção apresenta o perfil do beneficiário do PBF, visando caracterizar o público alvo do programa, enquanto a seção seguinte resume os principais estudos econométricos sobre a participação dos beneficiários no mercado de trabalho. Os estudos analisados não encontraram evidências do efeito preguiça – ou apenas efeitos muito pequenos em alguma subpopulação, p. ex., uma redução pequena no número de horas trabalhadas pelas mães. Outro resultado é a constatação de que estes estudos oferecem poucas informações sobre as opções de trabalho para a pessoas pobres e extremamente pobres. Por isso, a quarta seção se dedica a uma tarefa mais sociológica: a contextualização do mercado de trabalho para essa população, abordando o microempreendedorismo como uma porta de saída para as situações de trabalho degradante. Portanto, o receio de que o PBF faça com que os beneficiários trabalhem menos não é um fundamento consistente para criticar o programa.
Culturing Periprosthetic Tissues in BacT/Alert® Virtuo Blood Culture Bottles for a Short Duration of Post-operative Empirical Antibiotic Therapy
Authors: Duployez Claire , Wallet Frédéric , Migaud Henri , Senneville Eric , Loiez Caroline
Published: May 2020

Abstract. Introduction: A post-operative empirical antibiotic therapy (PEAT) is required in periprosthetic joint infections. It commonly uses broad-spectrum antibiotics to cover most Gram-positive cocci and Gram-negative bacilli. It is currently continued until first microbiological results are available, no less than five days later.Methods: We performed a retrospective study in order to evaluate duration of incubation required for surgical samples using the BacT/Alert® Virtuo blood culture bottles system.Results: Among 216 surgical interventions and 199 clinical strains (53.8% staphylococci, 22,1% streptococci and enterococci, 14,6% Gram-negative bacilli, 5,5% anaerobes), 90.5% of the strains were detected between day 0 and day 2; 15 infective strains are cultured from day 3 including 8 Cutibacterium sp., 4 staphylococci, 2 streptococci and 1 Enterococcus.Conclusions: We suggest that the duration of PEAT in patients operated for a periprosthetic joint infection may be shortened to three days as Gram-negative rods are unlikely to grow after three days of culture by using BacT/Alert® Virtuo blood culture bottles. This is likely to shorten the overall length of hospital stay, to diminish the occurrence of adverse side effects, and the emergence of antimicrobial resistance. However, coverage of Gram-positive cocci should be maintained for 14 days until the definite culture results are available.
Revealing the selective mechanisms of inhibitors to PARP-1 and PARP-2 via multiple computational methods
Authors: Hu Hongye , Chen Buran , Zheng Danni , Huang Guanli
Published: May 2020

Background

Research has shown that Poly-ADP-ribose polymerases 1 (PARP-1) is a potential therapeutic target in the clinical treatment of breast cancer. An increasing number of studies have focused on the development of highly selective inhibitors that target PARP-1 over PARP-2, its closest isoform, to mitigate potential side effects. However, due to the highly conserved and similar binding sites of PARP-1 and PARP-2, there is a huge challenge for the discovery and design of PARP-1 inhibitors. Recently, it was reported that a potent PARP-1 inhibitor named NMS-P118 exhibited greater selectivity to PARP-1 over PARP-2 compared with a previously reported drug (Niraparib). However, the mechanisms underlying the effect of this inhibitor remains unclear.

Methods

In the present study, classical molecular dynamics (MD) simulations and accelerated molecular dynamics (aMD) simulations combined with structural and energetic analysis were used to investigate the structural dynamics and selective mechanisms of PARP-1 and PARP-2 that are bound to NMS-P118 and Niraparib with distinct selectivity.

Results

The results from classical MD simulations indicated that the selectivity of inhibitors may be controlled by electrostatic interactions, which were mainly due to the residues of Gln-322, Ser-328, Glu-335, and Tyr-455 in helix αF. The energetic differences were corroborated by the results from aMD simulations.

Conclusion

This study provides new insights about how inhibitors specifically bind to PARP-1 over PARP-2, which may help facilitate the design of highly selective PARP-1 inhibitors in the future.
Comparative Diagnosis of Latent Tuberculosis Infection amongst HIV and Diabetic Patients Attending Tertiary Hospitals in Anambra State
Authors: Chukwudi Ugwu Kenneth , Chuka Ene Paschal , MaryAnn. Orji  Nkeiru , Chinelo U. Umedum , Nnamdi Umetiti Chukwuemeka , Okwudiri Ikeanumba Michael
Published: May 2020

Aims: The aim of this research work was to survey the epidemiology and diagnosis of Latent Tuberculosis Infection (LTBI) amongst HIV and Diabetic patients in Anambra state of Nigeria using Tuberculin Skin Test (TST) and Interferon Gamma Release Assay (IGRA).

Study Design: This was a multicenter study covering three tertiary hospitals in Anambra State involving 480 adult HIV positive and Diabetic patients with 240 normal participants as control.

Place and Duration of Study:  This study conducted from February 2016 to April 2018 involved the general hospitals chosen from the three senatorial zones in the state. 

Methodology: IGRA using T spot TB as well as TST were done for all the participants. HIV screening, CD4 count and Fasting Blood Sugar were also done accordingly.

Results: Overall prevalence of Latent Tuberculosis Infection (LTBI) was 24.4% and 22.5% for IGRA and TST respectively, of the two health groups, HIV group had 35% and 20% for IGRA and TST respectively in their overall prevalence, this was significant (P<.05) compared with the controls which had 2.5% and 4% respectively to IGRA and TST. The diabetics group on the other hand had 13.8% and 25% for IGRA and TST respectively, this also was significant (P<.05) in comparison to its control group with 1.6% each for both IGRA and TST. Out of the 480 patients, 74(15.4%) of them had concordant result, this was 63.2% of the total positive value in the two groups worked on while 43(8.95%) and 34(7%) patients constituted the discordant figures for IGRA and TST respectively.CD4 count was inversely proportional to the presence of LTBI amongst HIV patients using the TST method. Age and duration of illness were significantly associated with LTBI in diabetics (P<.05). Participation rates were higher among males, though females recorded a non significant higher prevalence on the two test methods.

Conclusion: There was a high prevalence of latent tuberculosis infection amongst HIV and Diabetic patients in Anambra State. IGRA and TST diagnostic results were not concordant with each other but IGRA appeared to be more specific than TST in diagnosing LTBI.
Plant Tissue Cultures as Sources of Ingredients for Skin Care Applications
Authors: Apone Fabio , Tito Annalisa , Arciello Stefania , Carotenuto Gennaro , Colucci Maria Gabriella
Published: May 2020

In order to support their sessile lifestyle, plants evolved sophisticated defence mechanisms that result in the synthesis of a vast spectrum of chemical compounds. Plants have been the main source of natural ingredients for human use since ancient times and nowadays, with the development of plant tissue culture techniques, remarkable progresses towards the production of bioactive compounds on an industrial scale have been achieved, as plant tissue cultures represent standardized, contaminant‐free, and bio‐sustainable systems. In cosmetics, particularly as skin care applications, plant tissue cultures represent a valuable and promising source of active ingredients with a wide range of biological activities. While plant cells, grown as undifferentiated suspension cultures, could be a valuable source of active molecules which are normally synthesized in low amounts in differentiated tissues, hairy roots or somatic embryo cultures, due to their more specialized nature, synthetize compounds that can address more specific functions in skin care; although widespread in the pharmaceutical industry, plant tissue culture technology is not yet very common in the cosmetic field. The aim of the present article is to focus on the successful research accomplishments in the development of plant tissue cultures‐derived active ingredients for cosmetic applications.
But Weight, There's More: Genetic and Hormonal Control of Fruit Size in Fleshy Fruits
Authors: Read Nicola C. , Schaffer Robert J. , David Karine M.
Published: May 2020

Fleshy fruits come in a range of shapes and sizes, but each fruit is derived from a single meristematic growing point, with the final size determined by the number and plane of cell divisions and cell expansion during ovary and fruit development. During domestication, fruit size has been a selection criterion for most commercial fleshy fruits, and it is an important industry requirement. Extensive molecular work in model and non‐model plants has identified key genes that regulate fruit size including cell‐cycle‐related genes, meristem‐size‐associated genes, controllers of cell division, and genes associated with cell expansion and endoreduplication. These genes operate in a strongly regulated hormonal context that is also influenced by the environment of the plant. While the interaction of all three of these contributes to the final shape and size of the fruit, much research is still needed to fully understand fruit shape and size in fruits. However, key genes are emerging as potential targets to manipulate fruit size, allowing the development of new fruit cultivars.
An Ordered and Fail‐Safe Electrical Network in Cable Bacteria
Authors: Thiruvallur Eachambadi Raghavendran , Bonné Robin , Cornelissen Rob , Hidalgo‐Martinez Silvia , Vangronsveld Jaco , Meysman Filip J. R. , Valcke Roland , Cleuren Bart , Manca Jean V.
Published: May 2020

Cable bacteria are an emerging class of electroactive organisms that sustain unprecedented long‐range electron transport across centimeter‐scale distances. The local pathways of the electrical currents in these filamentous microorganisms remain unresolved. Here, the electrical circuitry in a single cable bacterium is visualized with nanoscopic resolution using conductive atomic force microscopy. Combined with perturbation experiments, it is demonstrated that electrical currents are conveyed through a parallel network of conductive fibers embedded in the cell envelope, which are electrically interconnected between adjacent cells. This structural organization provides a fail‐safe electrical network for long‐distance electron transport in these filamentous microorganisms. The observed electrical circuit architecture is unique in biology and can inspire future technological applications in bioelectronics.
Mechanical Properties Improvement in Highly and Aligned Dispersed Graphene Oxide/Bismaleimide Nanocomposites based on Graphene Oxide Sponge
Authors: Zhao Xu , Zhou Min , Peng Qingyu , Ding Renjie , Li Pengyang , Chen Qiang , Xu Liangliang , He Xiaodong
Published: May 2020

Graphene oxide (GO) as an excellent nanofiller is widely used to improve the mechanical properties of the resin matrix. The dispersion and distribution of GO sheets in the resin matrix have a strong impact on the mechanical properties of composites. Based on the action principle of GO sponge, a simple method for solving the highly and aligned dispersion of GO in the bismaleimide (BMI) resin is investigated. The GO bulk prepared by vacuum infusion using a porous GO sponge as a frame is smashed in the resin by the large shear force generated through the high‐speed stirring method. It is found that GO sheets have a highly dispersion in the BMI resin. A sample and new method for preparing GO aligned dispersion in resin by large deformation is provided to further enhance the mechanical properties of the resin. As expected, the flexural strength and flexural modulus of GO/BMI nanocomposites are enhanced by 39.6% and 45.5% than BMI resin. This simple dispersion method is easier to generalize to solve the dispensability of GO in other kinds of resins. In the future, there will be a broader application prospect in engineering applications.
An On‐Chip Break Junction System for Combined Single‐Molecule Conductance and Raman Spectroscopies
Authors: Jeong Hyunhak , Li Haipeng B. , Domulevicz Lucas , Hihath Joshua
Published: May 2020

Systems that are capable of robustly reproducing single‐molecule junctions are an essential prerequisite for enabling the wide‐spread testing of molecular electronic properties, the eventual application of molecular electronic devices, and the development of single‐molecule based electrical and optical diagnostics. Here, a new approach is proposed for achieving a reliable single‐molecule break junction system by using a microelectromechanical system device on a chip. It is demonstrated that the platform can (i) provide subnanometer mechanical resolution over a wide temperature range (≈77–300 K), (ii) provide mechanical stability on par with scanning tunneling microscopy and mechanically controllable break junction systems, and (iii) operate in a variety of environmental conditions. Given these fundamental device performance properties, the electrical characteristics of two standard molecules (hexane‐dithiol and biphenyl‐dithiol) at the single‐molecule level, and their stability in the junction at both room and cryogenic temperatures (≈77 K) are studied. One of the possible distinctive applications of the system is demonstrated, i.e., observing real‐time Raman scattering in a single‐molecule junction. This approach may pave a way to achieving high‐throughput electrical characterization of single‐molecule devices and provide a reliable platform for the convenient characterization and practical application of single‐molecule electronic systems in the future.
Tunable Dopants with Intrinsic Counterion Separation Reveal the Effects of Electron Affinity on Dopant Intercalation and Free Carrier Production in Sequentially Doped Conjugated Polymer Films
Authors: Aubry Taylor J. , Winchell K. J. , Salamat Charlene Z. , Basile Victoria M. , Lindemuth Jeffrey R. , Stauber Julia M. , Axtell Jonathan C. , Kubena Rebecca M. , Phan Minh D. , Bird Matthew J. , Spokoyny Alexander M. , Tolbert Sarah H. , Schwartz Benjamin J.
Published: May 2020

Carrier mobility in doped conjugated polymers is limited by Coulomb interactions with dopant counterions. This complicates studying the effect of the dopant's oxidation potential on carrier generation because different dopants have different Coulomb interactions with polarons on the polymer backbone. Here, dodecaborane (DDB)‐based dopants are used, which electrostatically shield counterions from carriers and have tunable redox potentials at constant size and shape. DDB dopants produce mobile carriers due to spatial separation of the counterion, and those with greater energetic offsets produce more carriers. Neutron reflectometry indicates that dopant infiltration into conjugated polymer films is redox‐potential‐driven. Remarkably, X‐ray scattering shows that despite their large 2‐nm size, DDBs intercalate into the crystalline polymer lamellae like small molecules, indicating that this is the preferred location for dopants of any size. These findings elucidate why doping conjugated polymers usually produces integer, rather than partial charge transfer: dopant counterions effectively intercalate into the lamellae, far from the polarons on the polymer backbone. Finally, it is shown that the IR spectrum provides a simple way to determine polaron mobility. Overall, higher oxidation potentials lead to higher doping efficiencies, with values reaching 100% for driving forces sufficient to dope poorly crystalline regions of the film.
Toward the Prediction and Control of Glass Transition Temperature for Donor–Acceptor Polymers
Authors: Zhang Song , Alesadi Amirhadi , Selivanova Mariia , Cao Zhiqiang , Qian Zhiyuan , Luo Shaochuan , Galuska Luke , Teh Catherine , Ocheje Michael U. , Mason Gage T. , St. Onge P. Blake J. , Zhou Dongshan , Rondeau‐Gagné Simon , Xia Wenjie , Gu Xiaodan
Published: May 2020

Semiconducting donor–acceptor (D–A) polymers have attracted considerable attention toward the application of organic electronic and optoelectronic devices. However, a rational design rule for making semiconducting polymers with desired thermal and mechanical properties is currently lacking, which greatly limits the development of new polymers for advanced applications. Here, polydiketopyrrolopyrrole (PDPP)‐based D–A polymers with varied alkyl side‐chain lengths and backbone moieties are systematically designed, followed by investigating their thermal and thin film mechanical responses. The experimental results show a reduction in both elastic modulus and glass transition temperature (Tg) with increasing side‐chain length, which is further verified through coarse‐grained molecular dynamics simulations. Informed from experimental results, a mass‐per‐flexible bond model is developed to capture such observation through a linear correlation between Tg and polymer chain flexibility. Using this model, a wide range of backbone Tg over 80 °C and elastic modulus over 400 MPa can be predicted for PDPP‐based polymers. This study highlights the important role of side‐chain structure in influencing the thermomechanical performance of conjugated polymers, and provides an effective strategy to design and predict Tg and elastic modulus of future new D–A polymers.
Quasi‐Binary Transition Metal Dichalcogenide Alloys: Thermodynamic Stability Prediction, Scalable Synthesis, and Application
Authors: Hemmat Zahra , Cavin John , Ahmadiparidari Alireza , Ruckel Alexander , Rastegar Sina , Misal Saurabh N. , Majidi Leily , Kumar Khagesh , Wang Shuxi , Guo Jinglong , Dawood Radwa , Lagunas Francisco , Parajuli Prakash , Ngo Anh Tuan , Curtiss Larry A. , Cho Sung Beom , Cabana Jordi , Klie Robert F. , Mishra Rohan , Salehi‐Khojin Amin
Published: May 2020

Transition metal dichalcogenide (TMDCs) alloys could have a wide range of physical and chemical properties, ranging from charge density waves to superconductivity and electrochemical activities. While many exciting behaviors of unary TMDCs have been demonstrated, the vast compositional space of TMDC alloys has remained largely unexplored due to the lack of understanding regarding their stability when accommodating different cations or chalcogens in a single‐phase. Here, a theory‐guided synthesis approach is reported to achieve unexplored quasi‐binary TMDC alloys through computationally predicted stability maps. Equilibrium temperature–composition phase diagrams using first‐principles calculations are generated to identify the stability of 25 quasi‐binary TMDC alloys, including some involving non‐isovalent cations and are verified experimentally through the synthesis of a subset of 12 predicted alloys using a scalable chemical vapor transport method. It is demonstrated that the synthesized alloys can be exfoliated into 2D structures, and some of them exhibit: i) outstanding thermal stability tested up to 1230 K, ii) exceptionally high electrochemical activity for the CO2 reduction reaction in a kinetically limited regime with near zero overpotential for CO formation, iii) excellent energy efficiency in a high rate Li–air battery, and iv) high break‐down current density for interconnect applications. This framework can be extended to accelerate the discovery of other TMDC alloys for various applications.
Graded 2D/3D Perovskite Heterostructure for Efficient and Operationally Stable MA‐Free Perovskite Solar Cells
Authors: Yao Qin , Xue Qifan , Li Zhenchao , Zhang Kaicheng , Zhang Teng , Li Ning , Yang Shihe , Brabec Christoph J. , Yip Hin‐Lap , Cao Yong
Published: May 2020

Almost all highly efficient perovskite solar cells (PVSCs) with power conversion efficiencies (PCEs) of greater than 22% currently contain the thermally unstable methylammonium (MA) molecule. MA‐free perovskites are an intrinsically more stable optoelectronic material for use in solar cells but compromise the performance of PVSCs with relatively large energy loss. Here, the open‐circuit voltage (Voc) deficit is circumvented by the incorporation of β‐guanidinopropionic acid (β‐GUA) molecules into an MA‐free bulk perovskite, which facilitates the formation of quasi‐2D structure with face‐on orientation. The 2D/3D hybrid perovskites embed at the grain boundaries of the 3D bulk perovskites and are distributed through half the thickness of the film, which effectively passivates defects and minimizes energy loss of the PVSCs through reduced charge recombination rates and enhanced charge extraction efficiencies. A PCE of 22.2% (certified efficiency of 21.5%) is achieved and the operational stability of the MA‐free PVSCs is improved.
Phase‐Separated, Printed Organic Thin‐Film Transistor‐Based Nonvolatile Memory with Enhanced Data Retention
Authors: Kim Woojo , Kwon Jimin , Lee Yongwoo , Baek Sanghoon , Jung Sungjune
Published: May 2020

A nonvolatile memory thin film transistor (TFT) is an essential building block in all electronic applications for calculation and identification. In particular, organic memory TFTs using bilayered polymer electrets have attracted significant attention due to excellent mechanical flexibility and fast operating speed. However, the data retention characteristics over an extended period of time remains a major reliability issue for nonvolatile memory devices. Here, the enhancement of data retention in flexible and printed organic memory TFTs by introducing a phase‐separated tunneling layer is demonstrated. The tunneling layer is formed during an active layer printing process with a blend ink of small‐molecule organic semiconductor and polystyrene insulator. The effect of the dielectric tunneling layer on data retention characteristics is systematically investigated. The printed nonvolatile memory devices with the phase‐separated tunneling layer exhibit significantly improved data retention time of over 10 years, validating the feasibility of applying flexible memory into wearable electronics and smart Internet‐of‐Things devices.
Color‐Tunable Boron‐Based Emitters Exhibiting Aggregation‐Induced Emission and Thermally Activated Delayed Fluorescence for Efficient Solution‐Processable Nondoped Deep‐Blue to Sky‐Blue OLEDs
Authors: Kim Hyung Jong , Godumala Mallesham , Kim Seong Keun , Yoon Jiwon , Kim Chae Yeong , Park Hanun , Kwon Jang Hyuk , Cho Min Ju , Choi Dong Hoon
Published: May 2020

Three new color‐tunable (deep‐blue to sky‐blue) and solution‐processable emitters—9′‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐9′H‐9,3′:6′,9″‐tercarbazole (TB‐3Cz), 9′‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐9,9″‐diphenyl‐9H,9′H,9″H‐3,3′:6′,3″‐tercarbazole (TB‐P3Cz), and 9‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐N3,N3,N6,N6‐tetraphenyl‐9H‐carbazole‐3,6‐diamine (TB‐DACz)—are demonstrated, which are cleverly designed and synthesized by appending a boron‐fused entity as an electron acceptor to different electron‐rich entities containing carbazole derivatives as donors. The thermal, photophysical, electrochemical, and electroluminescent characteristics of all the new materials are extensively investigated. Comprehensive photophysical investigations reveal that these emitters exhibit not only thermally activated delayed fluorescence (TADF) but also aggregation‐induced emission (AIE) properties. Consequently, solution‐processable organic light‐emitting diodes (OLEDs) fabricated using these new materials as nondoped emitters in the emissive layer exhibit a maximum external quantum efficiency (EQE) and Commission Internationale de l'Éclairage (CIE) color coordinates of 9.90% and (0.17, 0.07), respectively, for TB‐3Cz; 6.13% and (0.15, 0.08), respectively, for TB‐P3Cz; and 6.04% and (0.18, 0.40), respectively, for TB‐DACz. As far as it is known, the performance and ultrahigh color purity satisfying the deep‐blue CIE coordinates of the National Television System Committee (NTSC) for TB‐3Cz and TB‐P3Cz are the highest reported thus far for nondoped solution‐processable TADF emitters, indicating the great potential of these materials as deep‐blue luminogens in OLED applications.
Enabling Ultrathin Metamaterial Absorbers with Narrow Slits
Authors: Fu Jichao , Dong Hongguang , He Jinlong , Sun Yuwei , Jin Yi , He Sailing
Published: May 2020

Metamaterial absorbers (MAs) consisting of subwavelength units offer flexible design freedom and prominent advantages over traditional absorbers. Here, it is found that narrow slits provide the MAs a significant passageway to control the absorption behavior and obtain an ultrasmall thickness. As narrowing the slits in an MA gradually, two effects appear in turn, of which the former is that the slits help the localized energy leak away from the resonant units to balance the material absorption and radiation leakage rates and sustain perfect absorption, and the latter is that acting as a capacitor, the slits red‐shift the absorption peak. A record ultrathin microwave MA with a thickness of only 1/474 of the working wavelength is demonstrated. Colossal electric field is excited inside ultranarrow slits by the assistance of localized resonance in collecting the incident wave. The finding can be extended to other frequencies, and is fascinating for some areas requiring ultrathin absorption structures or strong interaction between waves and matters.
Rotational Offset Microlens Arrays for Highly Efficient Structured Pattern Projection
Authors: Yang Sung‐Pyo , Kim Jae‐Beom , Seo Yeong‐Hyeon , Jeong Ki‐Hun
Published: May 2020

This article reports the diffractive optical elements of rotational offset microlens arrays for generating highly efficient structured light patterns in active stereoscopic 3D imaging. The double‐side configuration of microlens arrays increases the uniformity of diffraction patterns by using two successive refractions on microlens surfaces. In addition, the rotational offsets between the frontside and the backside microlens arrays with rectangular or hexagonal arrangements control the contrast and the density of structured dot array patterns. Two layers of microlens arrays with high curvature and high fill‐factor are microfabricated on both sides of the glass wafer by using ultrathin fluorocarbon encapsulation, thermal reflow, and parylene gap filling. The rotational offset angles of 22.5°, 28°, and 37° in rectangular and 13.25°, 21.75°, and 27.75° in hexagonal arrangements efficiently provide diffractive dot arrays with high uniformity, contrast, and density by minimizing the overlapping of diffractive patterns. The active stereo imaging using rotational offset microlens arrays successfully acquire high‐resolution depth map for 3D plaster objects with smooth and curved surfaces. The structured light pattern projection using rotational offset microlens arrays will provide promising opportunities for compact advanced imaging systems in industrial, medical, or military applications.
Halogen Substitution in Zero‐Dimensional Mixed Metal Halides toward Photoluminescence Modulation and Enhanced Quantum Yield
Authors: Li Mingze , Li Yawen , Molokeev Maxim S. , Zhao Jing , Na Guangren , Zhang Lijun , Xia Zhiguo
Published: May 2020

Zero‐dimensional (0D) organic−inorganic hybrid metal halides haveunprecedented degrees of freedom for structural tunability and photoluminescence modulation. Here, the 0D isomorphic hybrid metal mixed halides (C9NH20)9Pb3Zn2Br19(1−x)Cl19x (x = 0–1) with continuous halogen contents control, exhibiting tunable emission and enhancement of photoluminescence quantum yield (PLQY) are reported. The competitive bromine to chlorine substitution process in (C9NH20)9Pb3Zn2Br19(1−x)Cl19x occurs first in [ZnBr4−xClx]2− tetrahedron before the [Pb3Br11−xClx]5− trimer. The increasing Cl content in samples from x = 0 to 1 results in an expected blue shift of emission peak from 565 to 516 nm, and meanwhile a strikingly room temperature PL quantum yield increase from 8% to 91%. Combined experimental characterizations and theoretical calculations indicate that the blue shift of interband transition energy is responsible for the emission peak shift. Moreover, with the increasing Cl content, the enhanced electron−phonon interaction and the weakened thermal‐assisted nonradiative recombination result in more efficient radiative transition channels and ultimately enhanced PLQY. The impact of halogen substitution on electronic structures and optical properties in 0D hybrid metal halides is emphasized in this work as a new strategy to promote the future development of new luminescent materials.