bluuebunny/crossref_metadata_2025 huggingface dataset:
La televisión y pautas de conducta de los jóvenes salvadoreños
Authors: Vaquerano de Portillo Edith Ruth , Alfaro Alfaro Domingo Orlando
Published: May 2019

Este artículo es producto de una investigación correlacional descriptiva realizada entre 1.207 jóvenes salvadoreños, con el objetivo de determinar si existe relación entre sus hábitos de consumo televisivo y sus pautas de conducta. Los resultados apuntan a la televisión como medio dominante en el que se busca sobre todo entretenimiento, con la Internet afianzándose en un sólido segundo lugar. Sin embargo, esa preferencia por el medio, aun y cuando los datos obtenidos permiten percibir una asociación entre su consumo y la manera en la que los jóvenes hablan, se comportan, lucen o piensan, no llegan a establecerse correlaciones estadísticas, con lo que habría que virar la vista hacia los hechos de que los receptores tienen un papel activo, de que la influencia de la televisión no es una variable unidimensional, y de que las interacciones sociales y el contexto deben ser considerados en profundidad. Para ello, es necesario recurrir a otros enfoques en la investigación, al estudio cualitativo. No obstante, la adopción de estrategias de educación para los medios, y especialmente para el consumo de la televisión, es una necesidad que se impone.
Formación ciudadana en jóvenes y su impacto en el proceso democrático del país
Authors: Campos Morán Saúl
Published: May 2019

El objetivo de la investigación fue conocer el nivel de formación política, la formación ciudadana, el conocimiento hacia la participación y la actitud hacia la participación ciudadana existente en los jóvenes salvadoreños. La investigación fue de tipo ex post facto con diseño transversal. Los sujetos del estudio son la población joven de El Salvador, siendo representados con una muestra probabilística de 482 sujetos, distribuidos entre los catorce departamentos del país. Entre los resultados principales de la investigación se tiene que, de acuerdo al nivel escolar de los sujetos, se encuentran diferencias significativas en la participación política, la formación ciudadana y la actitud hacia la participación, y que el disponer de un trabajo influye en la actitud que se tiene hacia los procesos políticos nacionales.
Responsabilidad legal en el manejo y disposición de desechos sólidos en hospitales de El Salvador
Authors: Morán Carolina Lucero
Published: May 2019

El objetivo de esta investigación es determinar la responsabilidad legal que tienen los hospitales en el manejo de los residuos sólidos, peligrosos y bioinfecciosos. Estos desechos, provenientes del aparato nosocomial, a menudo no son tratados según las normas técnicas estipuladas para ello, por lo que no solo se convierten en amplios fómites transmisores de enfermedades, sino que han pasado a formar parte de las grandes acumulaciones de basura que día a día se observan en diferentes partes del país. A su vez, generan desbalances en el medio ambiente, considerando que se suman a la gran acumulación de residuos sólidos en el entorno, transformándose, desde sus vertederos, en generadores de gases de efecto invernadero, sumándose a los problemas ambientales existentes. A menudo esos desechos no son manipulados con el cuido y las recomendaciones estipuladas por el Ministerio de Salud y a la luz de las recomendaciones internacionales. Ha perseguido además establecer si los hospitales están cumpliendo con las medidas de seguridad recomendadas para el manejo de los desechos sólidos, a efecto de delimitar la frontera de su responsabilidad y el inicio de la responsabilidad del recolector.
Diseño de un modelo de vivienda bioclimática y sostenible. Fase II
Authors: Vidal Vidales Ana Cristina , Vásquez Guillermo Francisco
Published: May 2019

Con esta investigación se busca retroalimentar la propuesta de vivienda planteada en la primera fase de la investigación, por medio de un experimento en el cual se midieron datos de temperatura y humedad relativa, en modelos a escala hechos con tres sistemas constructivos livianos diferentes. De esta forma es posible determinar, cuál sistema constructivo es más apto para las distintas condiciones climáticas que se presentan en el país, de acuerdo con las características propias de cada sitio. La investigación se complementa con una profundización de los elementos que deben ser tomados en cuenta en el diseño de una vivienda que satisfaga las necesidades básicas y la aplicación del diseño bioclimático, proponiendo modelos conceptuales que contienen alternativas tecnológicas, y se analiza su factibilidad de aplicación.
Gravimetric Quantification of Hydrophobic Fulvic Acids in Lignite Material Using Acetone
Authors: Liem L. Edwin , Serben Tannis , Cano Mariana
Published: May 2019

This study evaluated the gravimetric quantification of fulvic components in lignite material. The current standard method considered only components soluble in both alkali and acid solutions and adsorpted to a hydrophobic resin (DAX-8) at pH 1, identified as hydrophobic fulvic acids
(HFA). HFA were desorpted using 0.1 M sodium hydroxide (NaOH) and run through a cation exchange resin (IR-120) to remove Na ions. HFA were quantified gravimetrically, including ash corrections. Steps involving IR-120, however, resulted in a large volume of analytical solution and a significant
time of analysis, which became a disadvantage of this method. A modification to this method was proposed by replacing NaOH with acetone to desorpt HFA from DAX-8. IR-120 was not required, and a smaller volume of analytical solution was produced. Gravimetric, Fourier transform infrared (FTIR),
and ionic analyses were completed in this study. Both standard and modified methods resulted in the presence of hydrophobic neutrals within the quantification of HFA. Acetone at 50% strength produced HFA results corresponding to those of NaOH. An adequate regeneration of DAX-8 was achieved
using the modified method but not with the standard method. The modified method produced higher ash contents, but they did not affect its accuracy. This method significantly reduced the overall analytical time. This study showed the potential of acetone as a desorpting agent in the gravimetric
quantification of HFA in lignite material.
Da Ernst Christiansen blev »opdaget«.
Authors: Fink Troels
Published: May 2019

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Generation of endogenous pH-sensitive EGF receptor and its application in high-throughput screening for proteins involved in clathrin-mediated endocytosis
Authors: Larsen Mads Breum , Perez Verdaguer Mireia , Schmidt Brigitte F , Bruchez Marcel P , Watkins Simon C , Sorkin Alexander
Published: May 2019

Previously we used gene-editing to label endogenous EGF receptor (EGFR) with GFP and demonstrate that picomolar concentrations of EGFR ligand drive signaling and endocytosis of EGFR in tumors in vivo (Pinilla-Macua et al., 2017). We now use gene-editing to insert a fluorogen activating protein (FAP) in the EGFR extracellular domain. Binding of the tandem dye pair MG-Bis-SA to FAP-EGFR provides a ratiometric pH-sensitive model with dual fluorescence excitation and a single far-red emission. The excitation ratio of fluorescence intensities was demonstrated to faithfully report the fraction of FAP-EGFR located in acidic endosomal/lysosomal compartments. Coupling native FAP-EGFR expression with the high method sensitivity has allowed development of a high-throughput assay to measure the rates of clathrin-mediated FAP-EGFR endocytosis stimulated with physiological EGF concentrations. The assay was utilized to screen a phosphatase siRNA library. These studies highlight the utility of endogenous pH-sensitive FAP-receptor chimeras in high-throughput analysis of endocytosis.
Impact of metalorganic vapor phase epitaxy growth conditions on compressive strain relaxation in polar III-nitride heterostructures
Authors: Rudinsky Mikhail E. , Lobanova Anna V. , Karpov Sergey Yu. , Talalaev Roman A.
Published: May 2019

A novel approach to estimating the critical thicknesses (CTs) of compressively strained III-nitride layers is suggested, based on a quasi-thermodynamic growth model and accounted for the effect of material decomposition during dislocation half-loop formation on the CT value. The approach provides good quantitative agreement with available data on CTs of MOVPE-grown InGaN/GaN and AlGaN/AlN epilayers. The extremely large CTs observed for high Al-content AlGaN alloys grown on bulk AlN substrates may be attributed, in particular, to the dominant AlGaN decomposition mechanism, producing group-III metallic liquid and gaseous nitrogen. The suggested approach may also be helpful for analysis of threading dislocation inclination in compressively strained layers and applicable to studying point defect formation in semiconductors and its dependence on growth conditions.
Circular RNAs as potential biomarkers and therapeutics for cardiovascular disease
Authors: Wang Weitie , Wang Yong , Piao Hulin , Li Bo , Huang Maoxun , Zhu Zhicheng , Li Dan , Wang Tiance , Xu Rihao , Liu Kexiang
Published: May 2019

Circular RNAs (circRNAs) are genetic regulators that were earlier considered as “junk”. In contrast to linear RNAs, they have covalently linked ends with no polyadenylated tails. CircRNAs can act as RNA-binding proteins, sequestering agents, transcriptional regulators, as well as microRNA sponges. In addition, it is reported that some selected circRNAs are transformed into functional proteins. These RNA molecules always circularize through covalent bonds, and their presence has been demonstrated across species. They are usually abundant and stable as well as evolutionarily conserved in tissues (liver, lung, stomach), saliva, exosomes, and blood. Therefore, they have been proposed as the “next big thing” in molecular biomarkers for several diseases, particularly in cancer. Recently, circRNAs have been investigated in cardiovascular diseases (CVD) and reported to play important roles in heart failure, coronary artery disease, and myocardial infarction. Here, we review the recent literature and discuss the impact and the diagnostic and prognostic values of circRNAs in CVD.
Leaf functional trait variation in a humid temperate forest, and relationships with juvenile tree light requirements
Authors: Lusk Christopher H.
Published: May 2019

The species-rich arborescent assemblages of humid tropical forests encompass much of the known range of the leaf economics spectrum, often including >20-fold variation in leaf lifespan. This suite of traits underpins a life-history continuum from fast-growing pioneers to slow-growing shade-tolerant species. Less is known about the range of leaf traits in humid temperate forests, and there are conflicting reports about relationships of these traits with the light requirements of temperate evergreen angiosperms. Here I quantify the range of leaf functional traits in a New Zealand temperate evergreen forest, and relationships of these traits with light requirements of juvenile trees and shrubs. Foliage turnover of saplings of 19 evergreen angiosperms growing beneath gaps (12–29% canopy openness) and in understories (1.2–2.9%) was measured over 12 months. Dry mass per area (LMA), dry matter content, thickness, density and nitrogen content (N) of leaves were also measured. Species minimum light requirements were indexed as the 10th percentile of the distribution of saplings in relation to canopy openness. Interspecific variation of leaf lifespan was ∼6-fold in gaps (0.6 to 3.8 yrs), and ∼11-fold in the understorey (0.7 to 7.7 yrs). Six small tree and shrub species are effectively leaf-exchangers, with leaf lifespans of c.1 year in gaps—albeit usually longer in the shade. Interspecific variation in other leaf traits was 2.5 to 4-fold. Lifespans and LMA of both sun and shade leaves were negatively correlated with species light requirements i.e., positively correlated with shade tolerance. However, light environment (gap vs shade) explained about the same amount of variation in LMA as species’ identity did. Species light requirements were not significantly correlated with leaf N, dry matter content, density or thickness—except for a marginally significant correlation with dry matter content of shade leaves. Species light requirements were thus less consistently related to leaf structural traits than appears to be the case in humid tropical forests. Whereas the wide interspecific variation in leaf economic traits of tropical rainforest species outweighs plastic response to light availability, temperate evergreen woody angiosperms appear to occupy a narrower range of the leaf economic spectrum. Standardization of the light environments in which LMA is measured is vital in comparative studies of humid temperate forest evergreens, because of countergradient responses of this trait to light, and because of the relative magnitudes of plastic and interspecific variation in LMA in these forests.
Climate Predictions for Ludhiana District of Indian Punjab under RCP 4.5 and RCP 8.5
Authors: Dar Mehraj U. Din , Aggarwal Rajan , Kaur Samanpreet
Published: May 2019

Climate change poses significant threats to global food security and water resources. In a present study, a Global Climate Model HAD GEM2-ES under RCPs 4.5 and 8.5 was used for climate prediction study. The study spanned 46 years of baseline (1970-2015) as well as two future periods’ mid-century (MC) (2020-2050) and end century EC (2060-2090). The results showed that the temperature would increase by 1.56°C and rainfall would decrease by 98 mm in MC (2020-2050); and 3.11°C and 90 mm in EC (2060-2090), respectively under RCP 4.5. In RCP 8.5 the increase in temperature and rainfall was 2.75°C and 153 mm, respectively in MC and the corresponding values in EC was 5.46°C and 251 mm, respectively.
Solving Delay Differential Equations Using Reformulated Block Backward Differentiation Formulae Methods
Authors: Sirisena U. W. , Yakubu S. Y.
Published: May 2019

In this paper, the conventional backward differentiation formulae methods for step numbers k = 3 and 4 were reformulated by shifting them one-step backward to produce two and three approximate solutions respectively, in a step when implemented in block form. The derivation of the continuous formulations of the reformulated methods were carried out through multistep collocation method by matrix inversion technique. The discrete schemes were deduced from their respective continuous formulations. The convergence analysis of the discrete schemes were discussed. The stability analysis of these schemes were ascertained and the P- and Q-stability were also investigated. When the discrete schemes were implemented in block form to solve some first order delay differential equations together with an accurate and efficient formula for the solution of the delay argument, it was observed that the results obtained from the schemes for step number k = 4 performed slightly better than the schemes for step number k = 3 when compared with the exact solutions. More so, on comparing these methods with some existing ones, it was observed that the methods derived performed better in terms of accuracy.
Gender Responsive Pedagogy: Practices, Challenges & Opportunities - A Case of Secondary Schools of North Wollo Zone, Ethiopia
Authors: Abraha Mollaw , Dagnew Asrat , Seifu Amera
Published: May 2019

The purpose of the current study was to examine the general secondary school (GSS) science teachers’ gender responsive pedagogy (GRP) implementation status. To do so, descriptive survey research design was employed.  Teachers, department heads and school principals were taken as respondents of the study comprehensively. And students were also participants of the study conveniently. Questionnaire, interview, and focus group discussion (FGD) were considered as the principal data collection tools. The collected data was analyzed both qualitatively and quantitatively: the data collected through questionnaire was analyzed via mean, std., one sample t-test.  And the data gathered by open ended items, interview, and FGD as well was analyzed via words, phrases, statements and narration.  The analyzed data noted that GSS science teachers of the North Wollo Zone had facilitated GRP fairly.  Thus, they found as effective in relation to language usage, classroom setups, classroom interaction, and addressing sexual harassment. To do so, availability of qualified school supervisors and principals, and realization of new education training policy (NETP) were considered as possible opportunities.  However, teachers as well ineffective to prepare gender responsive (GR) lesson plan, to prepare and use GR instructional materials and to have GR management of sexual maturation.  This vanity of teachers was sourced from ranges of challenges: economic, culture, school and teacher related.  Therefore, extra support in natural sciences should be given for girls beginning from lower primary education; Confidence building dialogues through involvement of female role model need to be initiated in schools; Gender based counseling, information and remedial learning programs like tutorial classes should be strengthened in schools; Since they used as experience sharing center, gender-sensitive expansion of ICT facilities, including computer labs and internet delivery infrastructure should be expanded in schools.
Lysosomal degradation of GMPPB is associated with limb‐girdle muscular dystrophy type 2T
Authors: Tian Wo‐Tu , Zhou Hai‐Yan , Zhan Fei‐Xia , Zhu Ze‐Yu , Yang Jie , Chen Sheng‐Di , Luan Xing‐Hua , Cao Li
Published: May 2019

Objective

GDP‐mannose pyrophosphorylase B (GMPPB) related phenotype spectrum ranges widely from congenital myasthenic syndrome (CMS), limb‐girdle muscular dystrophy type 2T (LGMD 2T) to severe congenital muscle‐eye‐brain syndrome. Our study investigates the clinicopathologic features of a patient with novel GMPPB mutations and explores the pathogenetic mechanism.

Methods

The patient was a 22‐year‐old woman with chronic proximal limb weakness for 9 years without cognitive deterioration. Weakness became worse after fatigue. Elevated serum creatine kinase and decrements on repetitive nerve stimulation test were recorded. MRI showed fatty infiltration in muscles of lower limbs and shoulder girdle on T1 sequence. Open muscle biopsy and genetic analysis were performed.

Results

Muscle biopsy showed myogenic changes. Two missense mutations in GMPPB gene (c.803T>C and c.1060G>A) were identified in the patient. Western blotting and immunostaining showed GMPPB and α‐dystroglycan deficiency in the patient's muscle. In vitro, mutant GMPPB forming cytoplasmic aggregates completely colocalized with microtubule‐associated protein 1 light chain 3‐II (LC3‐II), a classical marker of autophagosome. Degradation of GMPPB was accompanied by an upregulation of LC3‐II, which could be restored by lysosomal inhibitor leupeptin.

Interpretation

We identified two novel GMPPB mutations causing overlap phenotype between LGMD 2T and CMS. We provided the initial evidence that mutant GMPPB colocalizes with autophagosome at subcellular level. GMPPB mutants degraded by autophagy‐lysosome pathway is associated with LGMD 2T. This study shed the light into the enzyme replacement which could become one of the therapeutic targets in the future study.
Blood Pressure Trends in Patients With Seropositive Rheumatoid Arthritis Compared With Controls Without Rheumatoid Arthritis: A Retrospective Cohort Study
Authors: Boersma Peter , McElwee Matthew K. , Hashmi Hiba , Schreiner Pamela , Demmer Ryan T. , Shmagel Anna
Published: May 2019

Objective

Rheumatoid arthritis (RA) conveys an increased risk of cardiovascular disease (CVD), making it imperative that traditional CVD risk factors are well controlled. This study compared blood pressure (BP) trends over 13 years among patients with seropositive RA and patients without RA who received care within a large health care system in Minnesota.

Methods

This retrospective cohort study compared 774 patients with seropositive RA and 3254 patients without RA who were matched on sex and year of birth (±5 years) and observed between 2005 and 2017. Generalized estimating equation models were used for longitudinal analyses, with adjustment for demographics, body mass index, smoking status, Charlson Comorbidity Index, number of BP measurements, and number of antihypertensive and oral glucocorticoid medications.

Results

Patients both with and without RA had a mean age of 55 and were predominately female (78% with RA; 79% without RA). The mean follow‐up was 6.3 (SD 3.4) years for patients with RA and 7.2 (SD 3.3) years for patients without RA. Overall, systolic BP, diastolic BP, and the number of prescribed antihypertensive medications did not differ between groups. Patients with RA were more likely to be current smokers compared with patients without RA (23% vs 11%; P < 0.01) and were less likely to have serum lipid measurements (75% vs 85%; P < 0.01).

Conclusion

BP was similarly controlled in patients with seropositive RA and patients without RA. However, diastolic BP in patients with RA was trending up in most recent years. Patients with RA were also more likely to smoke compared with controls and were less likely to have serum lipid measurements.
Temperature‐ and Light‐Regulated Gas Transport in a Liquid Crystal Polymer Network
Authors: Cao Anping , van Raak Roel J. H. , Pan Xinglong , Broer Dirk J.
Published: May 2019

Azobenzene‐containing liquid crystal polymer networks (LCNs) are developed for temperature‐ and light‐regulated gas permeation. The order in a chiral‐nematic LCN (LCN*) is found to be essential to couple the unique structure of the membrane and its gas permeation responses to external stimuli such as temperature and varying irradiation conditions. An LCN membrane polymerized in the isotropic phase exhibits enhanced N2 permeation with increasing temperature, like most traditional polymers, but barely responds to exposure with 455 and 365 nm light. In sharp contrast, a reversible decrease of N2 transport is observed for the LCN* membrane of exactly the same chemical composition, but molecularly ordered, when submitted to an elevated temperature. More importantly, alternating in situ illumination with 455 and 365 nm light modulates reversibly N2 permeation performance of the LCN* membrane, through the trans–cis isomerization of azo moieties. The authors postulate that, besides the anisotropic deformation of LCN*, the decreased order in LCN* membrane caused by external stimuli (i.e., increasing temperature or UV light illumination) is responsible for an inhibition of gas permeation. These results show potential applications of liquid crystal polymers in the gas transport and separation, and also contribute to the development of “smart” membranes.
Compositional and Dimensional Control of 2D and Quasi‐2D Lead Halide Perovskites in Water
Authors: Jana Atanu , Ba Qiankai , Kim Kwang S.
Published: May 2019

Blue light emitting two dimensional (2D) and quasi‐2D layered halide perovskites (LHPs) are gaining attention in solid‐state lighting applications but their fragile stability in humid condition is one of the most pressing issues for their practical applications. Though water is much greener and cost effective, organic solvents must be used during synthesis as well as the device fabrication process for these LHPs due to their water‐sensitivity/instability and consequently, water‐stable blue‐light emitting 2D and quasi‐2D LHPs have not been documented yet. Here, water‐mediated facile and cost‐effective syntheses, characterizations, and optical properties of 16 organic–inorganic hybrid compounds are reported including 2D (A′)2PbX4 (A′ = butylammonium, X = Cl/Br/I) (8 compounds), 3D perovskites (4), and quasi‐2D (A′)pAx−1BxX3x+1 LHPs (A = methylammonium) (4) in water. Here, both composition and dimension of LHPs are tuned in water, which has never been explored yet. Furthermore, the dual emissive nature is observed in quasi‐2D perovskites, where the intensity of two photoluminescence (PL) peaks are governed by 2D and 3D inorganic layers. The Pb(OH)2‐coated 2D and quasi‐2D perovskites are highly stable in water even after several months. In addition, single particle imaging is performed to correlate structural–optical property of these LHPs.
Defect Engineering in Two Common Types of Dielectric Materials for Electromagnetic Absorption Applications
Authors: Quan Bin , Shi Wenhao , Ong Samuel Jun Hoong , Lu Xiaochi , Wang Paul Luyuan , Ji Guangbin , Guo Yufeng , Zheng Lirong , Xu Zhichuan J.
Published: May 2019

Dielectric materials are greatly desired for electromagnetic absorption applications. Lots of research shows that conduction loss and polarization are two of the most important factors determining complex permittivity. However, the detailed dissipation mechanisms for the improved microwave absorption performance are often based on semiempirical rules, lacking practical data relationships between conduction loss/polarization and dielectric behaviors. Here, a strategy of introducing point defects is used to understand such underlying relationships, where polarizability and conductivity are adjustable by manipulating oxygen deficiency or heteroatoms. Based on first principles calculations and the applied oxygen‐deficient strategy, dielectric polarization is shown to be dominant in determining the permittivity behaviors in semiconductors. Meanwhile, the presented nitrogen doping strategy shows that conduction loss is dominant in determining the permittivity behavior in graphitized carbon materials. The validity of the methods for using point defects to explore the underlying relations between conduction loss/polarization and dielectric behaviors in semiconductor and graphitized carbon are demonstrated for the first time, which are of great importance in optimizing the microwave absorption performance by defect engineering and electronic structure tailoring.
Treefrog Toe Pad‐Inspired Micropatterning for High‐Power Triboelectric Nanogenerator
Authors: Bui Van‐Tien , Zhou Qitao , Kim Jong‐Nam , Oh Jung‐Hwan , Han Kwan‐Woo , Choi Ho‐Suk , Kim Sang‐Woo , Oh Il‐Kwon
Published: May 2019

Inspired by treefrog's toe pads that show superior frictional properties, herein, an industrially compatible approach is reported to make an efficient dielectric tribosurface design using customizable nonclose‐packed microbead arrays, mimicking the friction pads of treefrogs, in order to significantly enhance electrification performance and reliability of triboelectric nanogenerator (TENG). The approach involves using an engineering polymer to prepare a highly ordered large‐area concave film, and subsequently the molding of a convex patterned triboreplica in which the concave film is exploited as a reusable master mold. A nature‐inspired TENG based on the patterned polydimethylsiloxane (PDMS) paired with flat aluminum (Al) can generate a relatively high power density of 8.1 W m−2 even if a very small force of ≈6.5 N is applied. Moreover, the convex patterned PDMS‐based TENG possesses exceptional durability and reliability over 25 000 cycles of contact–separation. Considering the significant improvements in power generation of TENG; particularly at very small force, together with cost‐effectiveness and possibility of mass production, the present methodology may pave the way for large‐scale blue energy harvesting and commercialization of TENGs for many practical applications.
Photoelectric Synaptic Plasticity Realized by 2D Perovskite
Authors: Sun Yilin , Qian Liu , Xie Dan , Lin Yuxuan , Sun Mengxing , Li Weiwei , Ding Liming , Ren Tianling , Palacios Tomás
Published: May 2019

Recently, several light‐stimulated artificial synaptic devices have been proposed to mimic photonic synaptic plasticity for neuromorphic computing. Here, the photoelectric synaptic plasticity based on 2D lead‐free perovskite ((PEA)2SnI4) is demonstrated. The devices show a photocurrent activation in response to a light stimulus in a neuron‐like way and exhibit several essential synaptic functions such as short‐term plasticity (STP) and long‐term plasticity (LTP) as well as their transmission based on spike frequency control. The strength of synaptic connectivity can be effectively modulated by the duration, irradiance, and wavelength of light spikes. The ternary structure of (PEA)2SnI4 causes it to possess varied photoelectric properties by composition control, which enhances the complexity and freedoms required by neuromorphic computing. The physical mechanisms of the memory effect are attributed to two distinct lifetimes of photogenerated carrier trapping/detrapping processes modulated by controlling the proportion of Sn vacancies. This work demonstrates the great potential of (PEA)2SnI4 as a platform to develop future multifunctional artificial neuromorphic systems.
Printing Therapeutic Proteins in 3D using Nanoengineered Bioink to Control and Direct Cell Migration
Authors: Peak Charles W. , Singh Kanwar Abhay , Adlouni Mu'ath , Chen Jeffrey , Gaharwar Akhilesh K.
Published: May 2019

A nanoengineered bioink loaded with therapeutic proteins is designed to direct cell function in a 3D printed construct. The bioink is developed from a hydrolytically degradable polymer and 2D synthetic nanoparticle. The synthesis of poly(ethylene glycol)‐dithiothreitol (PEGDTT) via a Michael‐like step growth polymerization results in acrylate terminated degradable macromer. The addition of 2D nanosilicates to PEGDTT results in formation of shear‐thinning bioinks with high printability and structural fidelity. The mechanical properties, swelling kinetics, and degradation rate of 3D printed constructs can be modulated by changing the ratio of PEG:PEGDTT and nanosilicates concentration. Due to high surface area and charged characteristic of nanosilicates, protein therapeutics can be sequestered in 3D printing structure for prolong duration. Sustained release of pro‐angiogenic therapeutics from 3D printed structure, promoted rapid migration of human endothelial umbilical vein cell. This approach to design biologically active inks to control and direct cell behavior can be used to engineer 3D complex tissue structure for regenerative medicine.
Grain Boundary Engineering Nanostructured SrTiO3 for Thermoelectric Applications
Authors: Dylla Maxwell T. , Kuo Jimmy Jiahong , Witting Ian , Snyder Gerald Jeffrey
Published: May 2019

Nanostructuring to reduce thermal conductivity is among the most promising strategies for designing next‐generation, high‐performance thermoelectric materials. In practice, electrical grain boundary resistance can overwhelm the thermal conductivity reduction induced by nanostructuring, which results in worse overall performance. Since a large body of work has characterized the transport of both polycrystalline ceramics and single crystals of SrTiO3, it is an ideal material system for conducting a case study of electrical grain boundary resistance. An effective mass model is used to characterize the transport signatures of electrical grain boundary resistance and evaluate thermodynamic design principles for controlling that resistance. Treating the grain boundary as a secondary phase to the bulk crystallites explains the transport phenomena. Considering that the interface can be engineered by controlling oxygen partial pressure, temperature, and the addition of extrinsic elements into the grain boundary phase, the outlook for SrTiO3 as a nanostructured thermoelectric is promising, and the zT could be greater than 0.5 at room temperature.
MnO/Metal/Carbon Nanohybrid Lithium‐Ion Battery Anode With Enhanced Electrochemical Performance: Universal Facile Scalable Synthesis and Fundamental Understanding
Authors: Wang Xiaoyan , Ma Liujia , Ji Qing , Meng Jian‐Qiang , Liang Suzhe , Xu Zhuijun , Wang Meimei , Zuo Xiuxia , Xiao Ying , Zhu Jin , Xia Yonggao , Müller‐Buschbaum Peter , Cheng Ya‐Jun
Published: May 2019

MnO holds a great promise as an alternative lithium‐ion battery anode. It is crucial to improve the cyclic stability and rate capability of MnO‐based anodes. A facile scalable strategy to incorporate metal nanoparticles into the MnO/carbon anodes is developed as demonstrated by the MnO/Ag/C and MnO/Ni/C nanohybrids. Difunctional methacrylate monomers are used as solvent and carbon source, where the precursors of MnO and metal are homogeneously mixed at the molecular level and converted into a thermosetting polymer. MnO and metal nanoparticles are in situ formed and homogeneously embedded in the in situ formed carbon matrix after the carbonization process. The influence of the metal nanoparticles on the structure and properties of the MnO‐based anodes is systematically investigated. The mass composition of the MnO phase within the nanohybrid is controlled to be at a relatively low level, which is helpful for maintaining a good cyclic stability at the expense of the reversible capacities. However, the reversible capacities are increased by the incorporation of the metal nanoparticles due to enhanced electrochemical kinetics, where both excellent cyclic stability and rate performance are exhibited simultaneously. The mechanism responsible for the performance improvement is explored by electrochemical impedance spectroscopy, cyclic voltammetry, and temperature‐dependent resistivity measurements.
Multicolor Semiconductor Lasers
Authors: Zhuang Xiujuan , Ouyang Yu , Wang Xiaoxia , Pan Anlian
Published: May 2019

The ever‐increasing demand for information density and accuracy in highly integrated photonic devices calls for miniaturization of a coherent light source with broadband tunability and high stability. Wavelength tuning range, cavity Q factor, and threshold are three indicators of evaluating the performance of a nanoscale laser. Herein, the latest, effective materials and fundamental structures for multicolor semiconductor lasers including low dimensional II–VI semiconductors, III–V semiconductors, and lead halide perovskites are reviewed. Composition and bandgaps, novel cavity designs, lasing wavelength, Q factors of resonators, and lasing thresholds of the multicolor semiconductor lasers are compared and discussed. Finally, a summary and a future perspective of broadband tunable semiconductor lasers are given.
Arsenic Trioxide Impacts Viral Latency and Delays Viral Rebound after Termination of ART in Chronically SIV‐Infected Macaques
Authors: Yang Qing , Feng Fengling , Li Pingchao , Pan Enxiang , Wu Chunxiu , He Yizi , Zhang Fan , Zhao Jin , Li Ruiting , Feng Liqiang , Hu Fengyu , Li Linghua , Zou Huachun , Cai Weiping , Lehner Thomas , Sun Caijun , Chen Ling
Published: May 2019

The latent viral reservoir is the source of viral rebound after interruption of antiretroviral therapy (ART) and is the major obstacle in eradicating the latent human immunodeficiency virus‐1 (HIV‐1). In this study, arsenic class of mineral, arsenic trioxide, clinically approved for treating acute promyelocytic leukemia, is demonstrated to reactivate latent provirus in CD4+ T cells from HIV‐1 patients and Simian immunodeficiency virus (SIV)‐infected macaques, without significant systemic T cell activation and inflammatory responses. In a proof‐of‐concept study using chronically SIVmac239‐infected macaques, arsenic trioxide combined with ART delays viral rebound after ART termination, reduces the integrated SIV DNA copies in CD4+ T cells, and restores CD4+ T cells counts in vivo. Most importantly, half of arsenic trioxide‐treated macaques show no detectable viral rebound in the plasma for at least 80 days after ART discontinuation. Mechanistically, the study reveals that CD4 receptors and CCR5 co‐receptors of CD4+ T cells are significantly downregulated by arsenic trioxide treatment, which reduces susceptibility to infection after provirus reactivation. Furthermore, an increase in SIV‐specific immune responses after arsenic trioxide treatment may contribute to suppression of viral rebound. This work suggests that arsenic trioxide in combination with ART is a novel regimen in down‐sizing or even eradicating latent HIV‐1 reservoir.
Mesoporous Decoration of Freestanding Palladium Nanotube Arrays Boosts the Electrocatalysis Capabilities toward Formic Acid and Formate Oxidation
Authors: Ding Jia , Liu Zhi , Liu Xiaorui , Liu Jie , Deng Yida , Han Xiaopeng , Zhong Cheng , Hu Wenbin
Published: May 2019

Fabricating high‐performance electrocatalysts is the most critical step in commercializing direct formic acid or formate fuel cells. In this work, a dual‐template electrodeposition method is used to create freestanding mesoporosity decorated palladium nanotube arrays (P‐PdNTA) as a bifunctional electrocatalyst toward formic acid and formate oxidation (FAO/FOR). The phytantriol‐based soft template modifies the superficial chemistry of aluminum anodic oxide inner surfaces, thereby facilitating the regulated electrodeposition of highly stable palladium nanotubes. The sacrifice of the soft template generates substantial mesoporosity on the nanotubes, resulting in a 189% increase in the electrochemically active surface area with respect to the mesopore‐free PdNTA baseline. In addition, the soft template significantly increases the density of catalytically active sites per unit area via perturbation on routine nanotube growth, as evidenced by the doubled areal catalytic activity of P‐PdNTA versus PdNTA. Remarkably, the P‐PdNTA delivered gravimetric catalytic currents of 3.65 and 3.87 A mg−1 for FAO and FOR, which are 8.5 and 6.5 times higher, respectively, than those of commercial Pt/C. These values are among the most favorable reported and benefit from the unique synergy of fast substance transport, large electrochemical active surface area and high areal population of catalytically active sites.
Spatiotemporal distribution of individuals as an indicator for the social system of Lepilemur sahamalaza
Authors: Mandl Isabella , Holderied Marc , Schwitzer Christoph
Published: May 2019

Primate social systems are highly diverse, complicating the classification of particularly elusive species that are difficult to observe. The spatial distribution of individuals over time is a critica lindicator for the social organization and long‐term studies are important to establish patterns of social interactions. In recent years, species of the cryptic, nocturnal sportive lemurs of the genus Lepilemur were found to live in pairs in which a single male and a single female share and defend a mutual home range. The present study aimed to forward research into this underrepresented genus by determining the social organization and structure of the Sahamalaza sportive lemur, L. sahamalaza. We collected 773.15 hr of behavioral and GPS data during a period of 10 months (between 2015 and 2016) on 14 individuals: eight females and six males. There was no evidence of pair‐specific home range use as intra‐ and intersexual home range overlap was high. No pattern of social interactions between focal individuals could be distinguished despite high range overlap. Individuals met and interacted infrequently, resulting in an interaction rate of 0.32 interactions/hr. Sleeping associations between adult individuals were never observed. While both sexes had access to multiple potential mating partners, range sizes or ranging distances did not increase in mating periods. Overall, the social system of Sahamalaza sportive lemurs exhibits aspects of a solitary social organization and structure with potential for the polygamous mating system. These findings underline the importance of detailed social ecology studies that can provide the basis for understanding potential environmental influences on social system variability of closely related species.
Combined Alkali‐Organoammonium Structure Direction of High‐Charge‐Density Heteroatom‐Containing Aluminophosphate Molecular Sieves
Authors: Seo Seungwan , Ahn Nak Ho , Lee Jeong Hwan , Knight Lisa M. , Moscoso Jaime G. , Sinkler Wharton A. , Prabhakar Sesh , Nicholas Christopher P. , Hong Suk Bong , Lewis Gregory J.
Published: May 2019

The charge density mismatch concept was applied to the synthesis of high‐charge‐density silicoaluminophosphate SAPO‐69 (OFF) and SAPO‐79 (ERI) and zincoaluminophosphate PST‐16 (CGS), PST‐17 (BPH), PST‐19 (SBS), and ZnAPO‐88 (MER) molecular sieves. Combined alkali‐organoammonium structure direction in these systems is thus enabled. Structure direction is treated from the perspective of stabilizing an ionic framework, the relationships between reaction charge density (OH−/H3PO4), alkali and organoammonium content, and ionicity of tetrahedral framework atoms in successful structure direction are presented.
The Second Spacer Cation Assisted Growth of a 2D Perovskite Film with Oriented Large Grain for Highly Efficient and Stable Solar Cells
Authors: Lian Xiaomei , Chen Jiehuan , Qin Minchao , Zhang Yingzhu , Tian Shuoxun , Lu Xinhui , Wu Gang , Chen Hongzheng
Published: May 2019

The fabrication of high‐quality film with large grains oriented along the direction of film thickness is important for 2D Ruddlesden–Popper perovskite‐based solar cells (PVSCs). High‐quality 2D BA2MAn−1PbnI3n+1 (BA+=butylammonium, MA+=methylammonium, n=5) perovskite films were fabricated with a grain size of over 1 μm and preferential orientation growth by introducing a second spacer cation (SSC+) into the precursor solution. Dynamic light scattering showed that SSC+ addition can induce aggregation in the precursor solution. The precursor aggregates are favorable for the formation of large crystal grains by inducing nucleation and decreasing the nucleation sites. Applying phenylethylammonium as SSC+, the optimized inverted planar PVSCs presented a maximum PCE of 14.09 %, which is the highest value of the 2D BA2MAn−1PbnI3n+1 (n=5) PVSCs. The unsealed device shows good moisture stability by maintaining around 90 % of its initially efficiency after 1000 h exposure to air (Hr=25±5 %).
S‐Adamantyl Group Directed Site‐Selective Acylation: Applications in Streamlined Assembly of Oligosaccharides
Authors: Blaszczyk Stephanie A. , Xiao Guozhi , Wen Peng , Hao Hua , Wu Jessica , Wang Bo , Carattino Francisco , Li Ziyuan , Glazier Daniel A. , McCarty Bethany J. , Liu Peng , Tang Weiping
Published: May 2019

The site‐selective functionalization of carbohydrates is an active area of research. Reported here is the surprising observation that the sterically encumbered adamantyl group directed site‐selective acylation at the C2 position of S‐glycosides through dispersion interactions between the adamantyl C−H bonds and the π system of the cationic acylated catalyst, which may have broad implications in many other chemical reactions. Because of their stability, chemical orthogonality, and ease of activation for glycosylation, the site‐selective acylation of S‐glycosides streamlines oligosaccharide synthesis and will have wide applications in complex carbohydrate synthesis.
Non‐natural Photoenzymatic Controlled Radical Polymerization Inspired by DNA Photolyase
Authors: Zhou Fanfan , Li Ruoyu , Wang Xiao , Du Simin , An Zesheng
Published: May 2019

Inspired by DNA photolyase, a non‐natural photoenzymatic catalysis of common flavoproteins is developed for controlled radical polymerization under irradiation of visible light. This photoenzymatic polymerization is highly efficient under mild conditions, applicable to various monomer families, suitable for both homogeneous and heterogeneous media, and can be externally modulated by switching light on and off. A unique combination of the natural enzymatic deoxygenation with the non‐natural photoenzymatic process enables an unprecedented oxygen‐tolerant, visible‐light‐controlled radical polymerization using a single enzyme to be developed. Visible light activation of non‐natural catalytic functions of the widely distributed flavoproteins is an exciting conceptual advance and may uncover a hitherto underexplored field of photoenzymatic catalysis.
Encapsulating Perovskite Quantum Dots in Iron‐Based Metal–Organic Frameworks (MOFs) for Efficient Photocatalytic CO2 Reduction
Authors: Wu Li‐Yuan , Mu Yan‐Fei , Guo Xiao‐Xuan , Zhang Wen , Zhang Zhi‐Ming , Zhang Min , Lu Tong‐Bu
Published: May 2019

Improving the stability of lead halide perovskite quantum dots (QDs) in a system containing water is the key for their practical application in artificial photosynthesis. Herein, we encapsulate low‐cost CH3NH3PbI3 (MAPbI3) perovskite QDs in the pores of earth‐abundant Fe‐porphyrin based metal organic framework (MOF) PCN‐221(Fex) by a sequential deposition route, to construct a series of composite photocatalysts of MAPbI3@PCN‐221(Fex) (x=0–1). Protected by the MOF the composite photocatalysts exhibit much improved stability in reaction systems containing water. The close contact of QDs to the Fe catalytic site in the MOF, allows the photogenerated electrons in the QDs to transfer rapidly the Fe catalytic sites to enhance the photocatalytic activity for CO2 reduction. Using water as an electron source, MAPbI3@PCN‐221(Fe0.2) exhibits a record‐high total yield of 1559 μmol g−1 for photocatalytic CO2 reduction to CO (34 %) and CH4 (66 %), 38 times higher than that of PCN‐221(Fe0.2) in the absence of perovskite QDs.
Ligand‐Controlled Regiodivergent Enantioselective Rhodium‐Catalyzed Alkene Hydroboration
Authors: Bochat Andrew J. , Shoba Veronika M. , Takacs James M.
Published: May 2019

Regiocontrol in the rhodium‐catalyzed boration of vinyl arenes is typically dominated by the presence of the conjugated aryl substituent. However, small differences in TADDOL‐derived chiral monophosphite ligands can override this effect and direct rhodium‐catalyzed hydroboration of β‐aryl and β‐heteroaryl methylidenes by pinacolborane to selectively produce either chiral primary or tertiary borated products. The regiodivergent behavior is coupled with enantiodivergent addition of the borane. The nature of the TADDOL backbone substituents and that of the phosphite moiety function synergistically to direct the sense and extent of regioselectivity and enantioinduction. Twenty substrates are shown to undergo each reaction mode with regioselectivity values reaching greater than 20:1 and enantiomer ratios reaching up to 98:2. A variety of subsequent transformations illustrate the potential utility of each product.
Four‐Coordinate Copper Halonitrosyl {CuNO}10 Complexes
Authors: Bower Jamey K. , Sokolov Alexander Yu. , Zhang Shiyu
Published: May 2019

While copper nitrosyl complexes are implicated in numerous biological systems, isolable examples remain limited. In this report, we show that [Cl3CuNO]−, with a {CuNO}10 electron configuration, can be generated by nitrite reduction at a copper(I) dichloride anion or by nitric oxide addition to a copper(II) trichloride precursor. The bromide analogue, [Br3CuNO]− was synthesized analogously, and both copper halonitrosyl complexes were characterized by X‐ray diffraction and a variety of spectroscopic methods. Experimental data and multireference (CASSCF/NEVPT2) calculations provide strong evidence for a CuII–NO. ground state. Both [Cl3CuNO]− and [Br3CuNO]− release and recapture NO. reversibly, and exhibit nitrosative reactivities toward a wide range of biological nucleophiles, such as amines, alcohols, and thiols.
Demethylenation of Cyclopropanes via Photoinduced Guest‐to‐Host Electron Transfer in an M6L4 Cage
Authors: Cullen William , Takezawa Hiroki , Fujita Makoto
Published: May 2019

Unusual demethylenation reactions of cyclopropanes under UV‐light irradiation were found within a cavity of a photoactive coordination cage. The reaction proceeded via a guest‐to‐host electron transfer owing to the highly electron‐deficient nature of the cage. The reactions were highly chemoselective and enabled late‐stage derivatization of a steroid molecule, which led to a totally new un‐natural steroid.