bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water‐Stable Lanthanide Coordination Polymers with Triple Luminescent Centers for Tunable Emission and Efficient Self‐Calibration Sensing Wastewater Pollutants
Authors: Gao Enjun , Wu Shuangyan , Wang Jing , Zhu Mingchang , Zhang Ying , Fedin Vladimir P. 
Published: February 2020

AbstractConventional luminescent sensors relying on single emission responsive to analytes demonstrate limited sensitivity and selectivity and developing novel self‐calibration probes is highly required. A series of water‐stable coordination polymers (CPs) with three emitting centers for tunable emissions is reported. They are facilely synthesized by simultaneously doping red‐emitting Eu3+ and green‐emitting Tb3+ into the same framework. The versatile Eu0.67Tb0.33–CP is applied to conveniently distinguishing different nitroaromatics pollutants and multidimensional ratiometric sensing CrO42−/Cr2O72−. Specific nitroaromatics can cause unique changes to the ligand→Eu3+/Tb3+ energy transfer efficiency, while CrO42−/Cr2O72− intriguingly quench the three emissions at different rates. Each nitroaromatic exhibits notably correlation to a unique combination of the two ligand→Eu3+/Tb3+ emission intensity ratios, enabling a 2D fingerprint recognition. Furthermore, the concentration‐dependent evolution of the two ratios upon exposure to CrO42−/Cr2O72− can be mapped out, achieving a 3D code recognition. As a result, the sensor demonstrates selective recognition of 4‐nitrophenol and CrO42−/Cr2O72− with high sensitivity and selectivity as well as great recycling ability. Both the synthetic and sensing strategies present a promising strategy to develop facile and effective ratiometric sensors.
Manipulating Photoluminescence of Carbon G‐center in Silicon Metasurface with Optical Bound States in the Continuum
Authors: Zhu Liangqiu , Yuan Shuai , Zeng Cheng , Xia Jinsong 
Published: February 2020

AbstractIn this paper, a dielectric metasurface is demonstrated to manipulate the photoluminescence of the G‐centers introduced by nanopatterning of crystalline silicon. The metasurface consists of asymmetric holes arranged in a square array, which can transform the bound states in the continuum (BICs) with infinite quality factor to a quasi‐BICs, while maintaining high quality factor of the optical resonance. Compared with the photoluminescence of G‐centers with nonresonance enhancement, ≈40 times photoluminescence enhancement is achieved, accompanied by a near‐zero threshold at cryogenic temperature. In addition, the polarization of the photoluminescence is controlled by the structural asymmetry. These findings provide a novel approach to enhance and manipulate the photoluminescence of G‐centers and may anticipate for realizing light source in silicon.
A Thin‐Film Flexible Defect‐Mode Laser
Authors: Ali Taimoor , Lin Jia‐De , Snow Benjamin , Wang Xiuze , Elston Steve J. , Morris Stephen M. 
Published: February 2020

AbstractLaser emission from a flexible defect‐mode structure consisting of two photopolymerized liquid crystal thin films separated by a dye‐doped polymethylmethacrylate defect layer is demonstrated. A simple and cost‐effective film transfer technique is used to fabricate the flexible laser and the corresponding laser emission characteristics, which shows single‐mode laser emission at λ = 582 nm, with an excitation threshold of Eth = 12.3 ± 0.5 µJ cm−2 per pulse and a slope efficiency of ηs = 6.0 ± 0.3%, are presented. The polarization state of the laser emission are also presented and are compared with the findings reported in the literature. Finally, laser‐beam steering is demonstrated up to 42° by subjecting the device to a mechanically induced deformation that creates a radius of curvature of 5 mm, which is of potential interest for conformable and wearable technology platforms.
X‐Shaped Alignment of Chromophores: Potential Alternative for Efficient Organic Terahertz Generators
Authors: Lee Ji‐Ah , Kim Won Tae , Jazbinsek Mojca , Kim Deokjoong , Lee Seung‐Heon , Yu In Cheol , Yoon Woojin , Yun Hoseop , Rotermund Fabian , Kwon O‐Pil 
Published: February 2020

AbstractEfficient broadband organic terahertz (THz) generators using X‐shaped alignment of the nonlinear optical chromophores, as an alternative to the parallel alignment of chromophores in benchmark organic crystals, are reported. All the developed six organic benzothiazolium crystals exhibit an isomorphic X‐shaped alignment of chromophores, resulting in an unprecedentedly large off‐diagonal optical nonlinearity (>100 × 10−30 esu), which presents one of the largest off‐diagonal optical nonlinearity of organic crystals. The benzothiazolium crystals exhibit efficient broadband THz wave generation employing the off‐diagonal optical nonlinearity, in contrast to the present state‐of‐the‐art organic THz generators that mostly utilize diagonal optical nonlinearity. For using off‐diagonal and diagonal optical nonlinearities, the polarization of the optical pump is perpendicular and parallel, respectively, to the polar axis of crystals. In addition to a large THz wave generation efficiency with one order of magnitude higher peak‐to‐peak THz electric field than that generated in a 1.0‐mm‐thick inorganic benchmark ZnTe crystal, the benzothiazolium crystals generate broadband THz spectra with an upper cut‐off frequency of near 8 THz, and the absence of strong absorption dimples in the range of 0.5−4 THz. Therefore, the X‐shaped alignment of chromophores presents an interesting potential alternative for efficient broadband organic THz generators.
Nanophotonic Polarization Routers Based on an Intelligent Algorithm
Authors: Lu Cuicui , Liu Zhouhui , Wu You , Xiao Zhiyuan , Yu Dongyi , Zhang Hongyu , Wang Chenyang , Hu Xiaoyong , Liu Yong‐Chun , Liu Xiaohong , Zhang Xiangdong 
Published: February 2020

AbstractNanophotonic polarization routers, which can separate and steer light with different polarizations of transverse electric and transverse magnetic modes into different output ports, are an essential component of on‐chip integrated photonic circuits. By developing an intelligent algorithm that combines the genetic algorithm and the finite element method, various polarization routers possessing different operation bands, different structures, and different materials, which can be easily fabricated and integrated, are successfully designed. On‐chip ultrasmall silicon‐based polarization routers are experimentally demonstrated in the near‐infrared range. The footprint is only 970 nm × 1240 nm, which is the smallest demonstrated. The measured normalized transmission is up to 85% in the near infrared range. Additionally, a broadband highly efficient photon coupler is also achieved based on disordered‐grating configurations designed by the intelligent algorithm. This breaks the restrictions of traditional structures, provides a universal platform for the realization of nanophotonic polarization routers, and paves a way for the design and high‐density on‐chip integration of nanophotonic devices.
Multiscale Simulation of Photoluminescence Quenching in Phosphorescent OLED Materials
Authors: Symalla Franz , Heidrich Shahriar , Friederich Pascal , Strunk Timo , Neumann Tobias , Minami Daiki , Jeong Daun , Wenzel Wolfgang 
Published: February 2020

AbstractBimolecular exciton‐quenching processes such as triplet–triplet annihilation (TTA) and triplet–polaron quenching play a central role in phosphorescent organic light‐emitting diode (PhOLED) device performance and are, therefore, an essential component in computational models. However, the experiments necessary to determine microscopic parameters underlying such processes are complex and the interpretation of their results is not straightforward. Here, a multiscale simulation protocol to treat TTA is presented, in which microscopic parameters are computed with ab initio electronic structure methods. With this protocol, virtual photoluminescence experiments are performed on a prototypical PhOLED emission material consisting of 93 wt% of 4,4ʹ,4ʺ‐tris(N‐carbazolyl)triphenylamine and 7 wt% of the green phosphorescent dye fac‐tris(2‐phenylpyridine)iridium. A phenomenological TTA quenching rate of 8.5 × 10−12 cm3 s−1, independent of illumination intensity, is obtained. This value is comparable to experimental results in the low‐intensity limit but differs from experimental rates at higher intensities. This discrepancy is attributed to the difficulties in accounting for fast bimolecular quenching during exciton generation in the interpretation of experimental data. This protocol may aid in the experimental determination of TTA rates, as well as provide an order‐of‐magnitude estimate for device models containing materials for which no experimental data are available.
Threshold investment and firm viability: Evidence from commercial poultry farms in Nigeria
Authors: Sanou Awa , Liverpool‐Tasie Lenis S. O. , Kerr John M. 
Published: February 2020

AbstractRapidly increasing demand for animal protein in many countries in the Global South has generated an expansion of the poultry subsector. This sector is typically diverse, ranging from small backyard farms to commercial farms of varying sizes. As the subsector expands, little is known about the performance or viability of different sizes of operation. Is there a minimum investment required to establish a viable commercial farm? Focusing on Nigeria, Africa's largest economy and most populous country, this study uses nonparametric statistics, transition matrices, and parametric estimations to identify the equilibrium poultry farm size. We find consistent evidence of multiple equilibria, particularly a high‐ and low‐stable equilibrium separated by a threshold between small and large farms. Farms are highly likely to remain in the size category in which they begin; small poultry farms are unlikely to cross the threshold and transition to large ones. We also find that larger farms are better able to withstand a price shock than smaller farms, which are more likely to cease operations in the event of a shock. These underlying dynamics should be given due consideration by governments, donors and private sector as they enter the industry or encourage others to engage in it [EconLit citations: O12‐Microeconomic Analyses of Economic Development, L11‐Production, Pricing, and Market Structure • Size Distribution of Firms, Q12‐Micro Analysis of Farm Firms, Farm Households, and Farm Input Markets].
Clinical manifestations of osteogenesis imperfecta in adulthood: An integrative review of quantitative studies and case reports
Authors: Chougui Khadidja , Addab Sofia , Palomo Telma , Morin Suzanne N. , Veilleux Louis‐Nicolas , Bernstein Mitchell , Thorstad Kelly , Hamdy Reggie , Tsimicalis Argerie 
Published: February 2020

AbstractOsteogenesis imperfecta (OI) is a rare genetic disorder of the bones caused by a mutation in Type I collagen genes. As adults with OI are aging, medical concerns secondary to OI may arise. This integrative review sought to review, appraise, and synthesize the clinical manifestations faced by adults with OI. Four electronic bibliographic databases were searched. Published quantitative, qualitative, and mixed‐methods studies, as well as case reports from 2000 to March 2019, addressing a clinical manifestation in adulthood, were reviewed. Eligible studies and case reports were subsequently appraised using the Mixed Methods Appraisal Tool and Case Report Checklist, respectively. Twenty quantitative studies and 88 case reports were included for review regardless of the varying methodological quality score. These studies collectively included 2,510 adults with different OI types. Several clinical manifestations were studied, and included: hearing loss, cardiac diseases, pregnancy complications, cerebrovascular manifestations, musculoskeletal manifestations, respiratory manifestations, vision impairment, and other clinical manifestations. Increased awareness may optimize prevention, treatment, and follow‐up. Opportunities to enhance the methodological quality of research including better design and methodology, multisite collaborations, and larger and diverse sampling will optimize the generalizability and transferability of findings.
Isotopic niche partitioning in two sympatric howler monkey species
Authors: Flores‐Escobar Elizabeth , Sanpera Carolina , Jover Lluís , Cortés‐Ortiz Liliana , Rangel‐Negrín Ariadna , Canales‐Espinosa Domingo , Dias Pedro Américo D. 
Published: February 2020

AbstractObjectivesEcological similarity between species can lead to interspecific trophic competition. However, when ecologically similar species coexist, they may differ in foraging strategies and habitat use, which can lead to niche partitioning. As the body tissues of consumers contain a stable isotope signature that reflects the isotopic composition of their diet, stable isotope analysis is a useful tool to study feeding behavior. We measured the isotopic niche width, which is a proxy for trophic niche width, of mantled (Alouatta palliata) and black (A. pigra) howler monkeys. Specifically, studied populations in allopatry and sympatry to assess whether these species showed niche partitioning.Materials and MethodsBetween 2008 and 2012, we collected hair samples from 200 subjects (113 black and 87 mantled howler monkeys) and used continuous flow isotope ratio mass spectrometry to estimate δ13C and δ15N. We described the isotopic niche width of each species in allopatry and sympatry with the Bayesian estimation of the standard ellipse areas.ResultsIn allopatry, isotopic niche width and isotopic variation were similar in both species. In sympatry, black howler monkeys had a significantly broader isotopic niche, which was mainly determined by high δ15N values, and included the majority of mantled howler monkeys' isotopic niche. The isotopic niche of mantled howler monkeys did not differ between sympatry and allopatry.ConclusionsThe coexistence of these ecologically similar species may be linked to trophic niche adjustments by one species, although the particular features of such adjustments (e.g., dietary, spatial, or sensory partitioning) remain to be addressed.
Wood and meat as complementary sources of sodium for Kanyawara chimpanzees (Pan troglodytes)
Authors: Venable Emily M. , Machanda Zarin , Hagberg Lindsey , Lucore Jordan , Otali Emily , Rothman Jessica M. , Uwimbabazi Moreen , Wrangham Richard 
Published: February 2020

AbstractObjectivesSodium, a vital micronutrient that is often in scarce supply for tropical herbivores, is sometimes found at high concentration in decaying wood. We tested two hypotheses for chimpanzees: first, that wood‐eating facilitates acquisition of sodium; second, that wood‐eating occurs in response to the low availability of sodium from other dietary sources.Materials and MethodsWe studied the behavior of more than 50 chimpanzees of all age‐sex classes in the Kanyawara community of Kibale National Park, Uganda. We quantified the sodium content of dietary items, including wood samples from tree species that chimpanzees consumed or did not consume. To assess variation in sodium intake, we used 7 years of data on time spent feeding on plant foods, 18 months of data on rates of food intake by adult females, and 20 years of data on meat‐eating.ResultsMajor dietary sources of sodium were wood, fruits and meat. Chimpanzees consumed wood primarily from decaying trees of Neoboutonia macrocalyx (Euphorbiaceae), which had substantially higher sodium content than all other dietary items tested. Wood‐eating was negatively correlated with fruit‐eating. Females ate wood more often than males, while males had a greater probability of consuming meat at predation events.DiscussionWe propose that females ate wood more often than males because females had reduced access to meat, their preferred source of sodium. This hypothesis suggests that the need for sodium is a motivating reason for chimpanzees to consume both meat and wood.
A Direct Fluorescent Activity Assay for Glycosyltransferases Enables Convenient High‐Throughput Screening: Application to O‐GlcNAc Transferase
Authors: Alteen Matthew G. , Gros Christina , Meek Richard W. , Cardoso David A. , Busmann Jil A. , Sangouard Gontran , Deen Matthew C. , Tan Hong‐Yee , Shen David L. , Russell Cecilia C. , Davies Gideon J. , Robinson Phillip J. , McCluskey Adam , Vocadlo David J. 
Published: February 2020

AbstractGlycosyltransferases carry out important cellular functions in species ranging from bacteria to humans. Despite their essential roles in biology, simple and robust activity assays that can be easily applied to high‐throughput screening for inhibitors of these enzymes have been challenging to develop. Herein, we report a bead‐based strategy to measure the group‐transfer activity of glycosyltransferases sensitively using simple fluorescence measurements, without the need for coupled enzymes or secondary reactions. We validate the performance and accuracy of the assay using O‐GlcNAc transferase (OGT) as a model system through detailed Michaelis–Menten kinetic analysis of various substrates and inhibitors. Optimization of this assay and application to high‐throughput screening enabled screening for inhibitors of OGT, leading to a novel inhibitory scaffold. We believe this assay will prove valuable not only for the study of OGT, but also more widely as a general approach for the screening of glycosyltransferases and other group‐transfer enzymes.
A Benchtop Method for Appending Protic Functional Groups to N‐Heterocyclic Carbene Protected Gold Nanoparticles
Authors: DeJesus Joseph F. , Sherman Lindy M. , Yohannan Darius J. , Becca Jeffrey C. , Strausser Shelby L. , Karger Leonhard F. P. , Jensen Lasse , Jenkins David M. , Camden Jon P. 
Published: February 2020

AbstractThe remarkable resilience of N‐heterocyclic carbene (NHC) gold bonds has quickly made NHCs the ligand of choice when functionalizing gold surfaces. Despite rapid progress using deposition from free or CO2‐protected NHCs, synthetic challenges hinder the functionalization of NHC surfaces with protic functional groups, such as alcohols and amines, particularly on larger nanoparticles. Here, we synthesize NHC‐functionalized gold surfaces from gold(I) NHC complexes and aqueous nanoparticles without the need for additional reagents, enabling otherwise difficult functional groups to be appended to the carbene. The resilience of the NHC−Au bond allows for multi‐step post‐synthetic modification. Beginning with the nitro‐NHC, we form an amine‐NHC terminated surface, which further undergoes amide coupling with carboxylic acids. The simplicity of this approach, its compatibility with aqueous nanoparticle solutions, and its ability to yield protic functionality, greatly expands the potential of NHC‐functionalized noble metal surfaces.
Total Synthesis of α‐ and β‐Amanitin
Authors: Lutz Christian , Simon Werner , Werner‐Simon Susanne , Pahl Andreas , Müller Christoph 
Published: February 2020

Abstractα‐Amanitin and related amatoxins have been studied for more than six decades mostly by isolation from death cap mushrooms. The total synthesis, however, remained challenging due to unique structural features. α‐Amanitin is a potent inhibitor of RNA polymerase II. Interrupting the basic transcription processes of eukaryotes leads to apoptosis of the cell. This unique mechanism makes the toxin an ideal payload for antibody–drug conjugates (ADCs). Only microgram quantities of toxins, when delivered selectively to tumor sites through conjugation to antibodies, are sufficient to eliminate malignant tumor cells of almost every origin. By solving the stereoselective access to dihydroxyisoleucine, a photochemical synthesis of the tryptathion precursor, solid‐phase peptide synthesis, and macrolactamization we obtained a scalable synthetic route towards synthetic α‐amanitin. This makes α‐amanitin and derivatives now accessible for the development of new ADCs.
Identification of the nucleotide exchange factor BmGrpE and its role under high‐temperature stress in silkworm, Bombyx mori
Authors: Li Jinxin , Lu Zhengting , Mao Tingting , Li Mengxue , Wang Hui , Qu Jianwei , Chen Jian , Fang Yilong , Li Fanchi , Li Bing 
Published: February 2020

AbstractThe high‐temperature stress gene GrpE plays an important role in coping with high‐temperature stress. The mutation of key sites of this gene can improve the high‐temperature resistance of organisms. In the present study, using complementary DNAs from the silkworm fat body as the template, the open reading frame sequence of the GrpE gene (BmGrpE) was amplified and was found to be 644 bp in length and encode a protein with a predicted molecular weight of 24.1 kDa. The presence of a binding site for the heat shock transcription factor (Hsf1) at −1440 bp upstream of its coding region indicates that BmGrpE may respond to high‐temperature stress. BmGrpE was constitutively expressed throughout developmental stages, with the highest level observed in the 5th instar larvae stage. Moreover, in 5th instar larvae (the 3th day), BmGrpE was expressed in all tissues examined, with the highest levels in the fat body, silk gland, and midgut. Interestingly, under high‐temperature stress, TiO2 nanoparticle treatment increased the messenger RNA levels of BmGrpE in the fat body and silk gland. After treatment with dsRNA of BmGrpE, the cell viability of BmN cells was significantly decreased under 34°C and H2O2 stress (p < .05). Mutation of BmGrpE (H163L) enhanced the resistance of BmN cells under high‐temperature stress. These results provide new clues for the study of molecular mechanisms of insect resistance to high temperatures.
Novel pyrazolopyrimidine urea derivatives: Synthesis, antiproliferative activity, VEGFR‐2 inhibition, and effects on the cell cycle profile
Authors: Kassab Asmaa E. , El‐Dash Yara , Gedawy Ehab M. 
Published: February 2020

AbstractA series of novel diaryl urea pyrazolopyrimidine derivatives was designed and synthesized. All the synthesized compounds were evaluated for cytotoxic activity by the National Cancer Institute. A significant antiproliferative activity at a 10‐µM dose was shown by four compounds (5c, 5e, 5g, and 5h), and they were accordingly evaluated at five concentrations. They showed a potent and broad‐spectrum antiproliferative activity, with GI50 values between 0.553 and 3.80 µM and TGI values in the range of 2.17–100 µM. These four compounds potently inhibited the vascular endothelial growth factor receptor‐2 (VEGFR‐2) with IC50 values in the nanomolar range. Molecular docking attributed their potent VEGFR‐2 inhibitory activity to their interactions with key amino acids in the VEGFR‐2 active site. Their flow cytometric analysis showed that they exerted their cytotoxic activity by reduction of the cellular proliferation and by induction of cell cycle arrest at the G2/M phase. Additionally, they induced DNA degradation or fragmentation, confirming the role of apoptosis in the cancer cell death and cytotoxicity induced by these compounds.