bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual techniques for cervical cancer screening in Colombia
Authors: Gamboa Óscar , González Mauricio , Bonilla Jairo , Luna Joaquín , Murillo Raul , INC Cervical Cancer Screening Study Group
Published: April 2019

Introduction: Direct visual inspection for cervical cancer screening remains controversial, whereas colposcopy-biopsy is considered the gold standard for diagnosis of preneoplastic cervical lesions.Objectives: To determine the rates of cervical intraepithelial neoplasia grade 2 or more and of false positives for colposcopy and direct visual inspection.Materials and methods: Women aged 25-59 underwent direct visual inspection with acetic acid (VIA), Lugol’s iodine (VIA-VILI), and colposcopy. Punch biopsies were obtained for all positive tests. Using histology as the gold standard, detection and false positive rates were compared for VIA, VIA-VILI, and colposcopy (two thresholds). Sensitivity and false positive ratios with the corresponding 95% confidence intervals were estimated.Results: We included 5,011 women in the analysis and we obtained 602 biopsies. Positivity rates for colposcopy high-grade and low-grade diagnosis were 1.6% and 10.8%. Positivity rates for VIA and VIA-VILI were 7.4% and 9.9%. VIA showed a significantly lower detection rate than colposcopy with low-grade diagnosis as the threshold (SR=0.72; 95% CI 0.57-0.91), and significantly lower false positive rate (FPR=0.70; 95% CI 0.65-0.76). No differences between VIA-VILI and colposcopy low-grade threshold were observed. VIA and VIA-VILI showed significantly higher detection and false positive rates than colposcopy high-grade threshold. Sensitivity rates for visual inspection decreased with age and false positive rates increased. For all age groups, false positive rates for VIA and VIA-VILI were significantly higher than colposcopy.Conclusions: Detection rates for VIA-VILI similar to colposcopy low-grade threshold represent a chance to reduce cervical cancer mortality through see-and-treat approaches among women with limited access to health care. Lower detection rates suggest reviewing high-grade colposcopy findings as the threshold for biopsy in certain settings.
Costos atribuidos a las infecciones asociadas con la atención en salud en un hospital de Colombia, 2011-2015
Authors: Ortiz-Mayorga Judith L. , Pineda-Rodríguez Ivonne G. , Dennis Rodolfo J. , Porras Alexandra
Published: April 2019

Introducción. El análisis de los costos derivados de las infecciones asociadas con la atención en salud representa un desafío para el sistema de salud en Colombia dados sus factores determinantes.Objetivo. Determinar los factores relacionados con el aumento y la variabilidad de los costos de la atención hospitalaria por las infecciones asociadas con la atención en salud en un hospital de cuarto nivel de Bogotá, entre el 2011 y el 2015.Materiales y métodos. Se analizaron los costos de la atención de 292 pacientes, los cuales se estimaron para cada una de las actividades realizadas desde el momento de sospechar el cuadro infeccioso hasta su resolución. Dichos costos se estandarizaron según el valor del manual tarifario del Instituto de Seguros Sociales, ajustándolos por el índice de precios al consumidor para salud hasta el año 2014. Se determinaron los factores relacionados con el aumento del costo del manejo mediante un modelo logístico condicional.Resultados. La estancia hospitalaria de nueve días o más antes de la infección, se asoció con el aumento del costo directo del manejo de las infecciones relacionadas con la atención en salud (odds ratio, OR=2,06; IC95% 1,11-3,63). El costo medio del manejo de las infecciones fue de COP $1.190.879. Los antibióticos representaron el 41 % del valor total del tratamiento, seguidos de los exámenes de laboratorio, con un costo equivalente al 13,5 %.Conclusión. Se encontró una relación entre el costo del manejo de las infecciones asociadas con la atención en salud y la estancia hospitalaria previa a su aparición. Los antecedentes patológicos de los pacientes no se relacionaron con el aumento de los costos.
Propiedades psicométricas de la escala EMUN-AR determinadas mediante el análisis de Rasch
Authors: Rivera Mauricio , Cano Óscar , Rodríguez-Losada Jorge , Sánchez Ricardo
Published: April 2019

Introducción. Las escalas de autorreporte se han considerado útiles para evaluar y vigilar los síntomas de la enfermedad maníaco-depresiva. Uno de estos instrumentos, la escala de medición de la enfermedad maníaco-depresiva mediante autorreporte (EMUN-AR), no se ha validado aún.Objetivo. Validar la escala EMUN-AR usando el modelo de Rasch.Materiales y métodos. La escala EMUN-AR mide 26 ítems que evalúan por dimensiones los síntomas de la enfermedad maníaco-depresiva en tres categorías: frecuencia, intensidad y grado de molestia causada. Para evaluar las propiedades psicométricas de la escala, se efectuaron análisis factoriales exploratorios con el fin de tener una aproximación de su estructura latente, y se usaron modelos de Rasch que incluyeron la 'unidimensionalidad', la confiabilidad, el ajuste de ítems, el ordenamiento de umbrales, y los mapas de personas e ítems.Resultados. Se seleccionó una muestra de 267 pacientes hospitalizados, 204 de los cuales había sufrido un episodio maníaco (76,4 %) y estaba recibiendo tratamiento farmacológico. Se encontró una estructura factorial que puede resumirse en cuatro dominios: activación, inhibición, ideas depresivas e inadaptación. El análisis de Rasch evidenció la unidimensionalidad en los factores, adecuados valores de confiabilidad, buen ajuste de los 26 ítems en general (excepto en el ítem que mide las ideas de muerte o suicidio), un funcionamiento deficiente del sistema de calificación de los ítems y un cubrimiento limitado de los síntomas de la enfermedad correspondientes a las formas atenuadas.Conclusión. Se modificó la escala original en dos aspectos: se ajustó un ítem cuyos indicadores marginales tenían mal ajuste y se redujo el número de categorías. En su forma actual, el instrumento es apropiado para medir las formas graves de la enfermedad maníaco-depresiva, mas no así las atenuadas.
Factores socioeconómicos y clínicos asociados con infecciones oportunistas en pacientes con HIV afiliados al sistema de salud
Authors: Lopera Mónica María , Lemos Yesly
Published: April 2019

Introducción. A pesar de los avances clínicos, las infecciones oportunistas son la principal causa de morbimortalidad en pacientes con el virus de la inmunodeficiencia humana (HIV).Objetivos. Estimar la prevalencia de las infecciones oportunistas en pacientes con HIV afiliados al sistema de salud, y establecer su asociación con factores sociodemográficos y clínicos.Materiales y métodos. Se hizo un estudio observacional con enfoque analítico. Se analizaron 37.325 registros de personas con HIV afiliadas al sistema de salud. Se hizo el análisis bivariado usando las pruebas de ji al cuadrado y de varianza (ANOVA) ajustadas por Bonferroni y una regresión logística múltiple para la población adulta, con el fin de establecer la asociación entre los factores sociodemográficos y clínicos, y la presencia, por lo menos, de una infección oportunista como variable de respuesta.Resultados. El 18 % de las personas había tenido, por lo menos, una infección oportunista. Las más frecuentes en adultos fueron la tuberculosis y la toxoplasmosis cerebral, y en menores de 13 años, las neumonías y las diarreas. La prevalencia fue significativamente mayor en hombres (OR=1,5; IC95% 1,4-1,6), en mayores de 40 años (OR=1,6; IC95% 1,3-2,0), en desplazados (OR=1,7; IC95% 1,5-1,9) y en afiliados al régimen subsidiado y de excepción (OR=2,7; IC95% 2,1-3,4). En cuanto a los factores clínicos, la asociación fue significativa en pacientes diagnosticados más de diez años atrás (OR=1,6; IC95 1,5-1,7) y en aquellos con tratamiento antirretroviral (OR=4,4; IC95% 3,9-5,1) o discontinuidad en el tratamiento (OR=1,7; IC95 1,6-1,8). El análisis multivariado se hizo en adultos en estadio A de la infección, con resultados similares.Conclusiones. A pesar de la naturaleza prevenible de las infecciones oportunistas, su prevalencia fue alta y afectó predominantemente a los grupos más desfavorecidos de la sociedad.
Effect of Biofertilizers and Biocontrol Agents on Growth and Yield in off Season Brinjal under Low Cost Polyhouse
Authors: Lily Devi Khwairakpam , Chettri Smriti , Sharma Aribam Priya Mahanta , Jhajharia Deepak , Singh R. K.
Published: April 2019

An experiment was conducted to determine the combined effect of biofertilizers and biocontrol agents on growth and yield of brinjal (Solanum melongena L.) under low cost polyhouse during off season in the experimental polyhouse of the College of Agricultural Engineering and Post Harvest Technology (CAEPHT), Central Agricultural University (CAU), Ranipool, Sikkim, India. The experiment was planned with 3 treatments and six replications viz. T1- Farm Yard Manure 5 kg/m2, T2- FYM 5 kg/m2 + biofertilizer (a mixture of Azotobactor + PSB at the rate 10 g/kg FYM each), T3- FYM 5 kg/m2 + biofertilizer + biocontrol agent (a mixture of Pseudomonas fluorescens + Trichoderma at the rate 5 g/kg FYM each). There was a significant variation in vegetative growth and yield among all the treatments. The maximum plant height (45.62 cm), the number of branches/ plant (11.17) and the number of leaves/ plant (50.05),the number of fruits/ plant (38.9) and fruit yield/ plant (810 g) were observed with treatment T3 which was at par with the treatment T2 and were significantly higher than the treatment T1 receiving FYM singly. Organic manure (FYM) inoculated with biofertilizers may therefore, be recommended for organic brinjal production for cultivation under low cost polyhouses in Sikkim (India) and application of biocontrol agents may be limited to areas having some history of occurrence of diseases because it involves an extra production cost in the application of biocontrol agents.
Carbon Sequestration in Relation to Topographic Aspects and Land Use in Northeast of Thailand
Authors: Islam Kazi Kaimul , Anusontpornperm Somchai , Kheoruenromne Irb , Thanachit Suphicha
Published: April 2019

The Distribution of Species Abundances within natural communities – when properly analysed – can provide essential information regarding general aspects of the internal organisation of these communities. In particular, true species richness on the one hand and the intensity of the process of hierarchical structuring of species abundances on the other hand may be estimated independently and, thereby, can provide truly complementary information. In turn, specific issues may thereby be addressed. For example, whether one unique dominant factor or numerous combined factors are involved in the structuring process of a community can be tested contradictorily. Although these methods are not new conceptually, their implementation in common practice remains scarce. The reason is that the relevant implementation of these methods requires to be sure that virtually all member-species in the community have been sampled. As exhaustive samplings often reveal difficult to achieve in practice, an appropriate, least-biased procedure of numerical extrapolation of incomplete inventories is imperatively required.

Considering the steadily increasing threats to the environment and biodiversity, especially facing the on-going climatic change, time has come now with ever greater urgency to go beyond the apparent limits of non-exhaustive sampling and make the most of what is available in terms of recorded field data, whatever the degree of incompleteness of species inventories.

As a modest and limited attempt to concretise this wish at the local level, I try, hereafter, to highlight the importance of additional information that may be unveiled  through adequate post-analysis of a set of eight frog communities, recently inventoried by Katwate, Apte & Raut in an amphibian hot-spot in the north-western Ghats of India. At last, the likely variations of both total species richness and the intensity of hierarchical structuring of species abundance are simulated as an answer to the steadily increasing influence of the ongoing climatic change.
Climate Change Impacts on Livelihood Vulnerability Assessment-Adaptation and Mitigation Options in Marine Hot Spots in Kerala, India
Authors: S. Salim Shyam , Narayanakumar R. , Remya R. , Safeena P. K. , Rahman M. Ramees , James Harsha Elizabeth
Published: April 2019

Climate change, a global challenge facing mankind necessitates governments to develop mitigation and adaptation plans. The climate change has multidimensional impacts on environment, fishery, social, economic and development drivers.  Climate change hot spots –can be defined as the ‘live labs’ where the manifestation of the climate change impacts is observed “first”. The South west India has been recognised as one among the twenty four hot spot regions identified globally. The present paper assessed the climate change vulnerability of over 800 fisher households in two major fishing villages of Kerala from the south west hotspot regions of India. Exposure (E), Sensitivity (S) and Adaptive Capacity (AC) are the pertinent factors that determine the vulnerability of households which were captured using a structured household questionnaire. One ninety eight  indicators were identified in the construction of vulnerability indices of which 37 related to sensitivity, 36 related to exposure and the other 125 indicators dealt with adaptive capacity. The overall vulnerability of the regions was assessed and the analysis revealed that the Poonthura village of Kerala was more vulnerable when compared to Elamkunnapuzha. The coastal population on their vulnerability scores were categorised into low, moderate, high and very high based on score values and geo-spatial analysis was attempted.  The results revealed that majority of fisher households in both villages were highly vulnerable to climate change, which is a major cause of concern. The study advocates the need for a bottom up approach with the proactive participation of the fishers in developing location specific adaptation and mitigation plans to ensure the livelihood of the fishers and the sustainable development of the fisheries sector in the climate change regime.
Human Interaction with the Natural Environment: The POETICAS Model as a Framework for Understanding and Praxis in Late Modernity
Authors: J. Burns Thomas , Hekmatpour Peyman , C. Speer Kristen
Published: April 2019

Using the acronym POETICAS, we explore eight major facets of humankind’s relationship with the natural environment. We make the case that, while they are not mutually exclusive, they are nonetheless analytically distinct. We explore the roles of: 1) Population & demography; 2) Organizations & institutions; 3) Ecology; 4) Technology; 5) Illness & health; 6) Culture; 7) Affluence & inequality; and 8) Scale & time. We examine each of these facets in turn, looking not only at their main effects, but also considering many of the interactions among these factors in a broader ecological context. Building on earlier models, we make a case that this broader and more robust model can offer a framework for civic discourse about the human-environment interface that is useable to a wide array of audiences, including students and researchers as well as policy makers, members of social movement organizations, and engaged citizens seeking an overarching framework that can help make sense of a variety of otherwise disparate findings.
Water Resources Dynamics and Vulnerability in Rusizi National Park (Burundi) from 1984 to 2015, in the Context of Climate Change and Global Warming
Authors: Elysée Ntiranyibagira , Bienvenu Sambou , Thiam Abou , Xavier Naramabuye François , Thacienne Uwiringiyimana , Gloriose Umuziranenge , Fabien Muhirwa
Published: April 2019

The study of water resources’ dynamics and vulnerability in Rusizi national Park aimed to achieve the following objectives: (1) to identify, characterize and map water bodies, (2) to analyze and explain their periodical evolutions and (3) to analyze the spatial transformation processes affecting them. It is a contribution to the knowledge of the Park’s water resources for the development of monitoring systems and the sustainability of their functions as strategic ecosystems. It is based on the diachronic analysis of land cover from multi-date Landsat images of years 1984, 1990 and 2011 (TM), 2000 (ETM+) and 2015 (OLI-TIRS), landscape ecology tools and socio-economic and climate data. Supervised classification of images allowed the identification of 9 to 10 land cover classes including water bodies, according to years. A total number of 17 water bodies were detected from 1984 to 2015. During this period, regularly detected and dried up water bodies represent 18.2% and 54.6% respectively. The rates of water bodies’ drying up were 69.2% in 2000 and 64.2% in 2015. Water bodies are experiencing a great deterioration in number, size and stability. The Park's water coverage has decreased from 3.56% in 1984 to 2.43% in 2015. This corresponds to a decline of 31.2%. The water bodies’ stability, which was 75.70% between 1984 and 1990, represents only 42.78% between 1984 and 2015. The stability of individual water bodies is decreasing as well while low spatial connectivities are being observed between some close water bodies. The spatial transformation processes carrying these dynamics are patch enlargement, patch creation, patch attrition and patch dissection, depending on the period. Global warming, rainfall variability and farming activities like land drainage and irrigation are the most important threats to water resources.
Explaining the Non-significant Changes in Ice-off Date over Six Decades at Lake of Bays and Lake Nipissing, South-Central Ontario
Authors: Yao Huaxia , Fu Congsheng
Published: April 2019

The phenomenon of non-significant trends in ice-off date under a warming climate was quantitatively explained by three efforts:  exploring possible driving factors where possible and defining new factors to represent snow conditions, identifying the contributing factors through correlation and trend tests, and evaluating relative contributions through partial Mann-Kendall method. Why the ice-off became only slightly earlier over 62 years at Lake of Bays has been satisfactorily assessed: the increased winter temperature, increased total rain and decreased days of snow on ground acted as three promoting drivers to earlier ice-off date, but their promoting functions were effectively offset by adverse changes in four other factors (snowfall slope, precipitation slope, snowpack slope, and last day of snow). The ice-off date at Lake Nipissing did not have a significant trend over 58 years, although there were five factors  contributing to the ice-off decline without sufficient offsetting, suggesting that the ice-off of this lake may not be sensitive, or basically elastic, to the climatic variation stressor. Relative contributions of drivers as calculated helped explain how much they contributed to ice-off trends or how much they offset the influences.
Improved Online Security Framework for e-Banking Services in Nigeria: A Real World Perspective
Authors: Sarjiyus O. , Oye N. D. , Baha B. Y.
Published: April 2019

Internet technology has given Banks the opportunity to provide customers robust, convenient and flexible banking services including, but not limited to fund transfers, account checking and payment of bills. Despite these huge benefits, e-banking has given rise to so many security concerns arising from countless threats. The rise in security threats against e-banking has caused a decline in the use of online banking and has negatively affected customer confidence in the ability of banks to protect their money and information and are looking up to the banks to fix the problems. This research, Improved Online Security Framework for e-banking services is geared towards developing an improved security framework that solves the issues of authentication, confidentiality, integrity and non-repudiation as it pertains to online banking attacks. Data was collected from primary and secondary sources ranging from interviewing relevant stakeholders that use internet banking to consultations of related journals articles and technical reports. Design and modeling tools such as UML usecases, Entity relationship (E-R) diagrams, process flow modeling and MySQL for a robust database design were used to capture basic system functionalities and artifacts required. The entire design was implemented on Visual studio platform. Upon running and testing on a XAMPP server, the system was found to meet all design objectives and operationally effective.
Effect of Deep Cryogenic Treatment on Microstructure and Properties of Pure Copper Processed by Equal Channel Angular Pressing
Authors: Wei Kun Xia , Chu Zhu Qi , Wei Wei , Du Qing Bo , Alexandrov Igor V. , Hu Jing
Published: April 2019

A new process combing equal channel angular pressing (ECAP) and deep cryogenic treatment (DCT) is proposed to balance the tensile strength and electrical conductivity of pure copper. The effect of the DCT on the microstructure and properties of pure copper processed by the ECAP is investigated. The optical microscopy (OM), transmission electron microscopy (TEM), and X‐ray diffraction (XRD) analyses are used to investigate the microstructure evolution. It shows that as a result of the ECAP, the shear bands are developed, the grains are obviously refined and the dislocation density increases. After the subsequent DCT, the grains are further refined and a large number of dislocations appear. With the increase of ECAP passes, the microhardness and tensile strength increase, however, the elongation to failure and electrical conductivity are degraded. The microhardness, tensile strength, elongation to failure, and electrical conductivity are enhanced by the DCT. The combination of tensile strength ≈423 MPa and electrical conductivity ≈97.9% international annealed copper standard (IACS) is simultaneously achieved after the ECAP (four passes) and DCT (24 h). Tensile properties can be improved by the DCT due to the increase of dislocation density and the grain refinement.
Nonstoichiometric Oxygen‐Dependent Microstructures and Phase Transitions in Post‐Annealed Vanadium Dioxides
Authors: Wang Shuxia , Wei Wei , Huang Tiantian , Zhang Tianning , Chen Zhimin , Chen Xin , Dai Ning
Published: April 2019

Vanadium dioxide (VO2) has a metal‐insulator transition (MIT) near room temperature and has attracted considerable interest in both the fundamental science and technological application communities. It is a challenging goal to facilitate a phase transition in complex vanadium oxides by manipulating the stoichiometry. More importantly, the specific hypoxic or hyperoxic microstructure phases simultaneously form when nonstoichiometric oxygen changes in the vanadium dioxides. Here, it is presented that the nonstoichiometric oxygen‐dependent microstructure, bandgap and MITs in post‐annealed VO2 thin films with V6O11 and V6O13 phases at the nanoscale. With an increase in nonstoichiometric oxygen, both the bandgap energies and the phase transition temperatures simultaneously increase. Controlling the hypoxic and hyperoxic states at the nanoscale is an alternative way to explore and manipulate MIT behaviors that depend on the microstructure and composition. It is believed that the dual perspectives help to both understand the underlying physical mechanism of collaborative MITs and construct functional Mott transistors based on multivalent VO2 thin films.
Anodic Synthesis of Hierarchical SnS/SnOx Hollow Nanospheres and Their Application for High‐Performance Na‐Ion Batteries
Authors: Bian Haidong , Li Zebiao , Xiao Xufen , Schmuki Patrik , Lu Jian , Li Yang Yang
Published: April 2019

Constructing hollow nanostructures is attractive for both fundamental research and practical applications. However, how to prepare hollow nanostructures in a simple, scalable, and cost‐effective way still remains a great challenge. In this study, for the first time, the anodization technique is applied to construct hollow nanostructures. Specifically, hollow nanospheres of SnS/SnOx with a hierarchical porous structure are self‐assembled directly on the Sn substrate, via a convenient one‐step anodization method. When applied for sodium‐ion batteries, the thus fabricated SnS/SnOx hollow nanospheres on the substrate readily serve as a binder‐free electrode, delivering remarkably high cycling stability and rate capability.
Branched and Dendritic Polymer Architectures: Functional Nanomaterials for Therapeutic Delivery
Authors: Cook Alexander B. , Perrier Sébastien
Published: April 2019

Barriers to therapeutic transport in biological systems can prevent accumulation of drugs at the intended site, thus limiting the therapeutic effect against various diseases. Advances in synthetic chemistry techniques have recently increased the accessibility of complex polymer architectures for drug delivery systems, including branched polymer architectures. This article first outlines drug delivery concepts, and then defines and illustrates all forms of branched polymers including highly branched polymers, hyperbranched polymers, dendrimers, and branched–linear hybrid polymers. Many new types of branched and dendritic polymers continue to be reported; however, there is often confusion about how to accurately describe these complex polymer architectures, particularly in the interdisciplinary field of nanomedicine where not all researchers have in‐depth polymer chemistry backgrounds. In this context, the present review describes and compares different branched polymer architectures and their application in therapeutic delivery in a simple and easy‐to‐understand way, with the aim of appealing to a multidisciplinary audience.
Boosting the Electrical Double‐Layer Capacitance of Graphene by Self‐Doped Defects through Ball‐Milling
Authors: Dong Yue , Zhang Su , Du Xian , Hong Song , Zhao Shengna , Chen Yaxin , Chen Xiaohong , Song Huaihe
Published: April 2019

Improving the capacitance of carbon materials for supercapacitors without sacrificing their rate performance, especially volumetric capacitance at high mass loadings, is a big challenge because of the limited assessable surface area and sluggish electrochemical kinetics of the pseudocapacitive reactions. Here, it is demonstrated that “self‐doping” defects in carbon materials can contribute to additional capacitance with an electrical double‐layer behavior, thus promoting a significant increase in the specific capacitance. As an exemplification, a novel defect‐enriched graphene block with a low specific surface area of 29.7 m2 g−1 and high packing density of 0.917 g cm−3 performs high gravimetric, volumetric, and areal capacitances of 235 F g−1, 215 F cm−3, and 3.95 F cm−2 (mass loading of 22 mg cm−2) at 1 A g−1, respectively, as well as outstanding rate performance. The resulting specific areal capacitance reaches an ultrahigh value of 7.91 F m−2 including a “self‐doping” defect contribution of 4.81 F m−2, which is dramatically higher than the theoretical capacitance of graphene (0.21 F m−2) and most of the reported carbon‐based materials. Therefore, the defect engineering route broadens the avenue to further improve the capacitive performance of carbon materials, especially for compact energy storage under limited surface areas.
Hydrogel Adhesion: A Supramolecular Synergy of Chemistry, Topology, and Mechanics
Authors: Yang Jiawei , Bai Ruobing , Chen Baohong , Suo Zhigang
Published: April 2019

Adhering hydrogels to various materials is fundamental to a large array of established and emerging applications. The last few years have seen transformative advances in achieving strong hydrogel adhesion, which is a supramolecular phenomenon. Two adherends connect through covalent bonds, noncovalent complexes, polymer chains, polymer networks, or nanoparticles. Separating the adherends dissipates energy through cascading events across length scales, including bond cleavage, chain retraction, and bulk hysteresis. A unifying principle has emerged: strong hydrogel adhesion requires the synergy of chemistry of bonds, topology of connection, and mechanics of dissipation. This synergy characterizes hydrogel adhesion to various materials (another hydrogel, tissue, elastomer, plastic, metal, glass, and ceramic) in various operations (cast, coat, print, attach, pierce, and glue). Strong adhesion can be made permanent, reversible, degradable, or on‐demand detachable. The development of hydrogel adhesion and its applications adheres disciplines, discovers interlinks, and forges cohesion. Discussed throughout the review are immediate opportunities for fundamental studies and practical applications.
Electrosynthesis of Hydrogen Peroxide Synergistically Catalyzed by Atomic Co–Nx–C Sites and Oxygen Functional Groups in Noble‐Metal‐Free Electrocatalysts
Authors: Li Bo‐Quan , Zhao Chang‐Xin , Liu Jia‐Ning , Zhang Qiang
Published: April 2019

Hydrogen peroxide (H2O2) is a green oxidizer widely involved in a vast number of chemical reactions. Electrochemical reduction of oxygen to H2O2 constitutes an environmentally friendly synthetic route. However, the oxygen reduction reaction (ORR) is kinetically sluggish and undesired water serves as the main product on most electrocatalysts. Therefore, electrocatalysts with high reactivity and selectivity are highly required for H2O2 electrosynthesis. In this work, a synergistic strategy is proposed for the preparation of H2O2 electrocatalysts with high ORR reactivity and high H2O2 selectivity. A Co−Nx−C site and oxygen functional group comodified carbon‐based electrocatalyst (named as Co–POC–O) is synthesized. The Co–POC–O electrocatalyst exhibits excellent catalytic performance for H2O2 electrosynthesis in O2‐saturated 0.10 m KOH with a high selectivity over 80% as well as very high reactivity with an ORR potential at 1 mA cm−2 of 0.79 V versus the reversible hydrogen electrode (RHE). Further mechanism study identifies that the Co−Nx−C sites and oxygen functional groups contribute to the reactivity and selectivity for H2O2 electrogeneration, respectively. This work affords not only an emerging strategy to design H2O2 electrosynthesis catalysts with remarkable performance, but also the principles of rational combination of multiple active sites for green and sustainable synthesis of chemicals through electrochemical processes.
Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency
Authors: Hanus Riley , Agne Matthias T. , Rettie Alexander J. E. , Chen Zhiwei , Tan Gangjian , Chung Duck Young , Kanatzidis Mercouri G. , Pei Yanzhong , Voorhees Peter W. , Snyder G. Jeffrey
Published: April 2019

The influence of micro/nanostructure on thermal conductivity is a topic of great scientific interest, particularly to thermoelectrics. The current understanding is that structural defects decrease thermal conductivity through phonon scattering where the phonon dispersion and speed of sound are assumed to remain constant. Experimental work on a PbTe model system is presented, which shows that the speed of sound linearly decreases with increased internal strain. This softening of the materials lattice completely accounts for the reduction in lattice thermal conductivity, without the introduction of additional phonon scattering mechanisms. Additionally, it is shown that a major contribution to the improvement in the thermoelectric figure of merit (zT > 2) of high‐efficiency Na‐doped PbTe can be attributed to lattice softening. While inhomogeneous internal strain fields are known to introduce phonon scattering centers, this study demonstrates that internal strain can modify phonon propagation speed as well. This presents new avenues to control lattice thermal conductivity, beyond phonon scattering. In practice, many engineering materials will exhibit both softening and scattering effects, as is shown in silicon. This work shines new light on studies of thermal conductivity in fields of energy materials, microelectronics, and nanoscale heat transfer.
Janus Graphene: Scalable Self‐Assembly and Solution‐Phase Orthogonal Functionalization
Authors: Jeon Intak , Peeks Martin D. , Savagatrup Suchol , Zeininger Lukas , Chang Sehoon , Thomas Gawain , Wang Wei , Swager Timothy M.
Published: April 2019

Orthogonal functionalization of 2D materials by selective assembly at interfaces provides opportunities to create new materials with transformative properties. Challenges remain in realizing controllable, scalable surface‐selective, and orthogonal functionalization. Herein, dynamic covalent assembly is reported that directs the functionalization of graphene surfaces at liquid–liquid interfaces. This process allows facile addition and segregation of chemical functionalities to impart Janus characteristics to graphenes. Specifically, dynamic covalent functionalization is accomplished via Meisenheimer complexes produced by reactions of primary amines with pendant dinitroaromatics attached to graphenes. Janus graphenes are demonstrated to be powerful surfactants that organize at water/organic, water/fluorocarbon, and organic/fluorocarbon liquid interfaces. This approach provides general access to the creation of diverse surfactant materials and promising building blocks for 2D materials.
Dynamics of Antimonene–Graphene Van Der Waals Growth
Authors: Fortin‐Deschênes Matthieu , Jacobberger Robert M. , Deslauriers Charles‐Antoine , Waller Olga , Bouthillier Étienne , Arnold Michael S. , Moutanabbir Oussama
Published: April 2019

Van der Waals (vdW) heterostructures have recently been introduced as versatile building blocks for a variety of novel nanoscale and quantum technologies. Harnessing the unique properties of these heterostructures requires a deep understanding of the involved interfacial interactions and a meticulous control of the growth of 2D materials on weakly interacting surfaces. Although several epitaxial vdW heterostructures have been achieved experimentally, the mechanisms governing their synthesis are still nebulous. With this perspective, herein, the growth dynamics of antimonene on graphene are investigated in real time. In situ low‐energy electron microscopy reveals that nucleation predominantly occurs on 3D nuclei followed by a self‐limiting lateral growth with morphology sensitive to the deposition rate. Large 2D layers are observed at high deposition rates, whereas lower growth rates trigger an increased multilayer nucleation at the edges as they become aligned with the Z2 orientation leading to atoll‐like islands with thicker, well‐defined bands. This complexity of the vdW growth is elucidated based on the interplay between the growth rate, surface diffusion, and edges orientation. This understanding lays the groundwork for a better control of the growth of vdW heterostructures, which is critical to their large‐scale integration.
Self‐Cleaning of Interfacial Oil Between Polymer Composites with Porous Zeolite Microparticles and Their Self‐Lubrication Properties
Authors: Ji Zhengjia , Xie Guoxin , Xu Wenhu , Wu Shuai , Zhang Lin , Luo Jianbin
Published: April 2019

Oil stain self‐cleaning and anti‐adhesion at the contacting interface between planar surfaces is a worldwide challenge and is rarely explored. Inspired by the low adhesion of Coccinella septempunctata to rough nanoporous substrates, it is attempted to reduce adhesion between the contacting interfaces of polymer composite due to the oil stain by constructing porous structures. A facile method is proposed to fabricate porous polymer composites by adding zeolite microparticles. Zeolite microparticles are used as oil cleaner to build the self‐cleaning system. The surface morphology, the mechanical properties, the anti‐adhesion and lubrication properties of the polymer composites are studied. It is suggested that the porous structure possesses self‐cleaning and high mechanical strength in ambient conditions. In addition, the excellent anti‐adhesion behavior can be realized due to the absorption of oil stain of the porous structure in the composite. The results show that the synergistic interaction of the roughness and the oleophilic properties decrease the adhesion between two planar surfaces under the oil stain condition. The present work provides a new route for the development of anti‐adhesion materials.
The Motivation for and Challenges to Scaling Down Organic Field‐Effect Transistors
Authors: Chan Paddy Kwok Leung
Published: April 2019

The development of organic field‐effect transistors (OFETs) in the past few decades has emphasized the carrier mobility of the active layer. It is true that carrier mobility is an important parameter to quantify transistor performance; however, it should not be considered as the only parameter necessary to evaluate the devices. To date, for extraction of the basic electrical properties of the active layers, OFETs fabricated in laboratories are mainly relatively large, with channel lengths ranging from tens to hundreds of micrometers. However, for practical applications, which demand more complicated circuits, scaling down of the OFETs, in particular the channel, is required. In these short‐channel OFETs, the roles of contact resistance, requirements on uniformity, and patterning techniques are all remarkably different from long‐channel devices. The challenges to scaling down OFETs are discussed and some potential approaches to address them.
Does obstetric protection apply to small‐bodied females?: A comparison between small‐bodied Jomon foragers and large‐bodied Yayoi agriculturalists in the prehistoric Japanese archipelago
Authors: Takamuku Hirofumi
Published: April 2019

Objectives

This study examined the relationship between maternal pelvic and body size in the transition from the Middle‐Final Jomon period (c. 5000–3000 BC) to the Middle Yayoi period (c. 400~200 BC to around AD 1) in Japan.

Methods

Eight measurements, including the left hip bone, articulated pelvis, and femur, were taken from Jomon (females: 37, males: 26) and Yayoi skeletal remains (females: 32, males: 29).

Results

A statistically significant decrease in the anterior diameter of the true pelvic inlet was demonstrated in females from the Jomon to the Yayoi period, but not in males. While significant increases in stature from the Jomon to the Yayoi period were found in both males and females, no significant changes in body mass were seen. The correlation coefficients between true and false pelvic measurements (maximum pelvic height and maximum pelvic breadth) and body size (stature and body mass) suggested few significant relationships between true and false pelvic measurements or body size among the samples, but no significant correlations in small‐bodied Jomon females. Results of principal component analysis using the log‐size and log‐shape variables suggested that the true pelvic size in Jomon and Yayoi females was not correlated with their general pelvic or body size, and there were correlations between sexually dimorphic aspects of true pelvis shape and either the false pelvis or body size in males but not females.

Conclusions

These results suggest that the obstetrical dimensions in small‐bodied Jomon females were maintained for obstetric needs.
Palladium‐Catalyzed Negishi Cross‐Coupling Reaction of Difluoroiodomethane with Arylzinc Reagents
Authors: Nitta Junki , Motohashi Hirotaka , Aikawa Kohsuke , Mikami Koichi
Published: April 2019

The catalytic difluoromethylation of arylzinc reagents with difluoroiodomethane in the presence of Pd2(dba)3/Xantphos is described to produce difluoromethyl products. Mechanistic investigations reveal that the oxidative addition of difluoroiodomethane to [(Xantphos)Pd0] provides trans‐[(Xantphos)PdII(I)CF2H], which is subsequently transformed to cis‐[(Xantphos)PdII(Ph)CF2H] through transmetalation of phenylzinc. Next, reductive elimination occurs (t1/2=44.7 min at −10 °C) to give PhCF2H. The structural changes in [(Xantphos)PdII(Ph)CF2H] from trans to cis facilitates reductive elimination of PhCF2H.
Electron Density Analysis for the H2+ System Confined by Hard Walls: The Chemical Bond Under Extreme Conditions
Authors: Hernández‐Esparza Raymundo , Landeros‐Rivera Bruno , Vargas Rubicelia , Garza Jorge
Published: April 2019

For the first time, the electron density of the H molecule is analyzed when this system is confined by spheroidal walls with an infinite potential. Typically, this system is studied to obtain information of the total energy and its components or to gain insight of some expected values when such a system is squeezed by this kind of confinement. However, this is the first report where the electron density and its derivatives, under the quantum theory of atoms in molecules (QTAIM), are analyzed to study the chemical bond involved with this molecule. This confinement induces an unexpected behavior of the chemical bond and gives an idea about atomic interactions under high pressures, where the QTAIM approach indicates that the chemical bond disappears. For strong confinements, there is a significant contribution of the electron kinetic energy and the nuclear‐electron energy contribution can be neglected. Under this situation, the confined H system is another example where the notion of the topological atom given by the QTAIM is no longer suitable.
Plasmonic Nanocavities Enable Self‐Induced Electrostatic Catalysis
Authors: Climent Clàudia , Galego Javier , Garcia‐Vidal Francisco J. , Feist Johannes
Published: April 2019

The potential of strong interactions between light and matter remains to be further explored within a chemical context. Towards this end herein we study the electromagnetic interaction between molecules and plasmonic nanocavities. By means of electronic structure calculations, we show that self‐induced catalysis emerges without any external stimuli through the interaction of the molecular permanent and fluctuating dipole moments with the plasmonic cavity modes. We also exploit this scheme to modify the transition temperatureT1/2of spin‐crossover complexes as an example of how strong light–matter interactions can ultimately be used to control a materials responses.
A Triskelion‐Shaped Saddle–Helix Hybrid Nanographene
Authors: Cruz Carlos M. , Márquez Irene R. , Castro‐Fernández Silvia , Cuerva Juan M. , Maçôas Ermelinda , Campaña Araceli G.
Published: April 2019

A unique rippled nanographene consisting of 52 fused rings is presented in which six out‐of‐plane motifs are fully fused into a triangular aromatic surface with a size of approximately 2.5 nm. Three units of an unprecedented fully lateral π‐extended octabenzo[5]helicene together with three units of saddle‐shaped heptagonal rings are combined in a single structure, leading to a well‐soluble warped nanographene. The two diastereomeric pairs of possible enantiomers were isolated, and their linear, non‐linear, and chiroptical properties were evaluated, revealing outstanding quantum yield and brightness values at low energy, together with good chiroptical responses in both absorption and emission.
The Natural Product Elegaphenone Potentiates Antibiotic Effects against Pseudomonas aeruginosa
Authors: Zhao Weining , Cross Ashley R. , Crowe‐McAuliffe Caillan , Weigert‐Munoz Angela , Csatary Erika E. , Solinski Amy E. , Krysiak Joanna , Goldberg Joanna B. , Wilson Daniel N. , Medina Eva , Wuest William M. , Sieber Stephan A.
Published: April 2019

Natural products represent a rich source of antibiotics that address versatile cellular targets. The deconvolution of their targets via chemical proteomics is often challenged by the introduction of large photocrosslinkers. Here we applied elegaphenone, a largely uncharacterized natural product antibiotic bearing a native benzophenone core scaffold, for affinity‐based protein profiling (AfBPP) in Gram‐positive and Gram‐negative bacteria. This study utilizes the alkynylated natural product scaffold as a probe to uncover intriguing biological interactions with the transcriptional regulator AlgP. Furthermore, proteome profiling of a Pseudomonas aeruginosa AlgP transposon mutant provided unique insights into the mode of action. Elegaphenone enhanced the elimination of intracellular P. aeruginosa in macrophages exposed to sub‐inhibitory concentrations of the fluoroquinolone antibiotic norfloxacin.
Electronic Communication across Porphyrin Hexabenzocoronene Isomers
Authors: Martin Max M. , Lungerich Dominik , Haines Philipp , Hampel Frank , Jux Norbert
Published: April 2019

Single‐molecule electronic components (SMECs) are envisioned as next‐generation building blocks in quantum circuit systems. However, challenges such as the reproducibility of the electrode attachment to the individual molecules hamper their fundamental investigation. For our purpose, we introduced quasi optoelectronic electrodes (QOEs) that allow for rapid investigations of the properties and suitability of compounds for molecular electronic devices. In particular, we probed hexa‐peri‐hexabenzocoronene (HBC) as a model system for D6h‐symmetrical nanographenes, with porphyrins as QOEs attached to the periphery. We prepared selectively bis‐porphyrin‐functionalized HBCs with ortho‐, meta‐ and para‐substitution and studied their communication properties, in correlation to the geometrical alignment and size of the system, by electrochemistry and optical spectroscopy. Further insights into structure–property relationships were gained by DFT calculations and X‐ray diffraction analysis.
Selective Sexual Dimorphisms in Musculoskeletal and Cardiopulmonary Pathologic Manifestations and Mortality Incidence in the Tumor Necrosis Factor–Transgenic Mouse Model of Rheumatoid Arthritis
Authors: Bell Richard D. , Wu Emily K. , Rudmann Christopher A. , Forney Megan , Kaiser Claire R. W. , Wood Ronald W. , Chakkalakal Joe V. , Paris Nicole D. , Klose Alanna , Xiao Guang‐Qian , Rangel‐Moreno Javier , Garcia‐Hernandez Maria L. , Ritchlin Christopher T. , Schwarz Edward M. , Rahimi Homaira
Published: April 2019

Objective

To examine and quantify the sexual dimorphism in pathologic features manifested in the musculoskeletal and cardiopulmonary systems and incidence of mortality in the tumor necrosis factor–transgenic (TNF‐Tg; Tg3647 strain) mouse model of inflammatory erosive arthritis.

Methods

Kaplan‐Meier survival estimates were determined in male and female Tg3647 mice and sex‐matched wild‐type (WT) littermate mice. Longitudinal and cross‐sectional pathologic outcomes in the musculoskeletal and cardiopulmonary systems were assessed via ultrasound, micro–computed tomography, grip strength measurements, histologic and serologic analyses, flow cytometry, and skeletal muscle physiologic measures.

Results

Compared to male Tg3647 mice (n = 30), female Tg3647 mice (n = 34) had significantly shorter lifespans (P < 0.001) and exhibited the following pathologic features (n = 4–6 per group; P < 0.05 versus male Tg3647 littermates): gross deficits in body mass and muscle weight, early‐onset inflammatory arthritis with severity of end‐stage arthritis that was as severe as that seen in male transgenic mice, and early onset and increased severity of inflammatory interstitial lung disease (ILD). Histologically, the ILD observed in Tg3647 mice was characterized by inflammatory cell accumulation and pulmonary arteriole thickening, which was concomitant with the presence of right ventricular hypertrophy, a feature that was also more severe in the female compared to male Tg3647 mice (P < 0.05). No sexual dimorphisms in TNF‐induced deficient grip strength, axial skeletal growth, or bone loss were found. Globally, the extent of the pathologic changes observed in female Tg3647 mice was greater than that observed in male Tg3647 mice when each group was compared to their sex‐matched WT littermates.

Conclusion

These findings indicate that TNF selectively drives the early onset of arthritis and progression of pathologic changes in the cardiopulmonary system in female Tg3647 mice. These results in the Tg3647 mouse identify it as a suitable model to better understand the mechanisms underlying sexual dimorphism and cardiopulmonary disease in the setting of inflammatory arthritis and other connective tissue diseases.