bluuebunny/crossref_metadata_2025 huggingface dataset:
Enantiomeric MOF Crystals Using Helical Channels as Palettes with Bright White Circularly Polarized Luminescence
Authors: Zhang Chong , Yan Zhi‐Ping , Dong Xi‐Yan , Han Zhen , Li Si , Fu Ting , Zhu Yan‐Yan , Zheng You‐Xuan , Niu Yun‐Yin , Zang Shuang‐Quan
Published: August 2020

The host–guest chemistry of metal–organic frameworks (MOFs) has enabled the derivation of numerous new functionalities. However, intrinsically chiral MOFs (CMOFs) with helical channels have not been used to realize crystalline circularly polarized luminescence (CPL) materials. Herein, enantiomeric pairs of MOF crystals are reported, where achiral fluorophores adhere to the inner surface of helical channels via biology‐like H‐bonds and hence inherit the helicity of the host MOFs, eventually amplifying the luminescence dissymmetry factor (glum) of the host l/d‐CMOF (±1.50 × 10−3) to a maximum of ±0.0115 for the composite l/d‐CMOF⊃fluorophores. l/d‐CMOF⊃fluorophores in pairs generate bright color‐tunable CPL and almost ideal white CPL (0.33, 0.32) with a record‐high photoluminescence quantum yield of ≈30%, which are further assembled into a white circularly polarized light‐emitting diode. The present strategy opens a new avenue for propagating the chirality of MOFs to realize universal chiroptical materials.
Graphene‐Quantum‐Dots‐Induced Centimeter‐Sized Growth of Monolayer Organic Crystals for High‐Performance Transistors
Authors: Wang Jinwen , Wu Xiaofeng , Pan Jing , Feng Tanglue , Wu Di , Zhang Xiujuan , Yang Bai , Zhang Xiaohong , Jie Jiansheng
Published: August 2020

Monolayer organic crystals have attracted considerable attention due to their extraordinary optoelectronic properties. Solution self‐assembly on the surface of water is an effective approach to fabricate monolayer organic crystals. However, due to the difficulties in controlling the spreading of organic solution on the water surface and the weak intermolecular interaction between the organic molecules, large‐area growth of monolayer organic crystals remains a great challenge. Here, a graphene quantum dots (GQDs)‐induced self‐assembly method for centimeter‐sized growth of monolayer organic crystals on a GQDs solution surface is reported. The spreading area of the organic solution can be readily controlled by tuning the pH value of the GQDs solution. Meanwhile, the π–π stacking interaction between the GQDs and the organic molecules can effectively reduce the nucleation energy of the organic molecules and afford a cohesive force to bond the crystals, enabling large‐area growth of monolayer organic crystals. Using 2,7‐didecyl benzothienobenzothiopene (C10‐BTBT) as an examples, centimeter‐sized monolayer C10‐BTBT crystal with uniform molecular packing and crystal orientation is attained. Organic field‐effect transistors based on the monolayer C10‐BTBT crystals exhibit a high mobility up to 2.6 cm2 V−1 s−1, representing the highest mobility value for solution‐assembled monolayer organic crystals. This work provides a feasible route for large‐scale fabrication of monolayer organic crystals toward high‐performance organic devices.
Time‐Gated FRET Nanoprobes for Autofluorescence‐Free Long‐Term In Vivo Imaging of Developing Zebrafish
Authors: Cardoso Dos Santos Marcelina , Colin Ingrid , Ribeiro Dos Santos Gabriel , Susumu Kimihiro , Demarque Michaël , Medintz Igor L. , Hildebrandt Niko
Published: August 2020

The zebrafish is an important vertebrate model for disease, drug discovery, toxicity, embryogenesis, and neuroscience. In vivo fluorescence microscopy can reveal cellular and subcellular details down to the molecular level with fluorescent proteins (FPs) currently the main tool for zebrafish imaging. However, long maturation times, low brightness, photobleaching, broad emission spectra, and sample autofluorescence are disadvantages that cannot be easily overcome by FPs. Here, a bright and photostable terbium‐to‐quantum dot (QD) Förster resonance energy transfer (FRET) nanoprobe with narrow and tunable emission bands for intracellular in vivo imaging is presented. The long photoluminescence (PL) lifetime enables time‐gated (TG) detection without autofluorescence background. Intracellular four‐color multiplexing with a single excitation wavelength and in situ assembly and FRET to mCherry demonstrate the versatility of the TG‐FRET nanoprobes and the possibility of in vivo bioconjugation to FPs and combined nanoprobe‐FP FRET sensing. Upon injection at the one‐cell stage, FRET nanoprobes can be imaged in developing zebrafish embryos over seven days with toxicity similar to injected RNA and strongly improved signal‐to‐background ratios compared to non‐TG imaging. This work provides a strategy for advancing in vivo fluorescence imaging applications beyond the capabilities of FPs.
Self‐Powered and Broadband Photodetector Based on SnS2/ZnO1−xSx Heterojunction
Authors: Jiang Jinchun , Huang Jiyu , Ye Zhizhen , Ruan Shuangchen , Zeng Yu‐Jia
Published: August 2020

Self‐powered photodetectors that can work without an external power source are expected to play a crucial role in future optoelectronic devices. Herein, SnS2/ZnO1−xSx heterojunctions are fabricated by a facile sputtering method and constructed as self‐powered broadband photodetectors covering from UV (365 nm) to NIR (850 nm). The self‐powered device shows a superior responsivity of 8.28 mAW−1, a photodetectivity of 5.09 × 1010 Jones, and a high Ion/Ioff ratio of 1.08 × 105 at 365 nm. Furthermore, the SnS2/ZnO0.7S0.3 heterojunction device presents a fast response speed with a rise time of 49.51 ms and a decay time of 25.93 ms. The high performance of the device is attributed to the type II band alignment of the heterojunction as well as the Schottky barrier. The high responsivity, fast response speed, large Ion/Ioff ratio, and broadband response enable the SnS2‐based heterojunction a potential candidate for self‐powered photodetectors in the range from UV to NIR.
Realizing Stretchable OLEDs: A Hybrid Platform Based on Rigid Island Arrays on a Stress‐Relieving Bilayer Structure
Authors: Kim Taehyun , Lee Hyeonwoo , Jo Woosung , Kim Taek‐Soo , Yoo Seunghyup
Published: August 2020

Optoelectronic devices that are stretchable can revolutionize various fields by enabling the functionalities that are not accessible from conventional rigid platforms. In this respect, many efforts are made to realize stretchable organic light‐emitting diodes (OLEDs) for their compatibility with various deformable substrates. Two representative examples of such efforts include a method based on intrinsically stretchable materials and a method to attach ultrathin OLEDs on a prestrained elastomer substrate. However, both of those methods have limitations either in material availability for high performance or in optical clarity. Here a hybrid platform is proposed for stretchable OLEDs free from such limitations. The proposed platform is composed of an array of rigid islands connected by serpentine‐shaped interconnectors formed on a bilayer elastomer substrate in which the top layer has an ultralow Young's modulus of ≈0.9 kPa, greatly relieving the rigid islands and interconnectors of the mechanical stress applied to them when stretched. With the proposed platform, stretchable OLEDs are demonstrated that can be repeatedly stretched by 140% and are based on thermally evaporable materials well established for fabrication of high‐performance OLEDs.
Consecutive C1‐Homologation / Displacement Strategy for Converting Thiosulfonates into O,S‐Oxothioacetals
Authors: Ielo Laura , Pillari Veronica , Miele Margherita , Holzer Wolfgang , Pace Vittorio
Published: August 2020

A conceptually intuitive synthesis of oxothioacetals is reported starting from thiosulfonates as electrophilic sulfur donors. The installation of a reactive CH2Cl motif with a homologating carbenoid reagent, followed by the immediate nucleophilic displacement with alcoholic groups [(hetero)‐aromatic, aliphatic] offer a convenient access to the title compounds. Genuine chemoselectivity is uniformly observed in the case of multi‐functionalized systems.

magnified image
Enhancing Delivery of Small‐Molecule‐ and Cell‐Based Therapies for Ovarian Cancer Using Advanced Delivery Strategies
Authors: O'Dwyer Joanne , O'Cearbhaill Roisin E. , Wylie Robert , O'Mahony Saoirse , O'Dwyer Michael , Duffy Garry P. , Dolan Eimear B.
Published: August 2020

Ovarian cancer is the most lethal gynecological malignancy with a global five‐year survival rate of 30–50%. First‐line treatment involves cytoreductive surgery and administration of platinum‐based small molecules and paclitaxel. These therapies are traditionally administered via intravenous infusion, although intraperitoneal delivery has also been investigated. Initial clinical trials of intraperitoneal administration for ovarian cancer indicate significant improvements in overall survival compared to intravenous delivery, but this result is not consistent across all studies performed. Recently, cell‐based immunotherapy has been of interest for ovarian cancer. Direct intraperitoneal delivery of cell‐based immunotherapies may prompt local immunoregulatory mechanisms to act synergistically with the delivered immunotherapy. Based on this theory, preclinical in vivo studies have delivered these cell‐based immunotherapies via the intraperitoneal route, with promising results. However, successful intraperitoneal delivery of cell‐based immunotherapy and clinical adoption of this technique depend on overcoming challenges of intraperitoneal delivery and finding the optimal combinations of dose, therapeutic, and delivery route. The potential advantages and disadvantages of intraperitoneal delivery of cell‐based immunotherapy for ovarian cancer and the preclinical and clinical work performed so far are reviewed. Potential advanced delivery strategies, which may improve the efficacy and adoption of intraperitoneal delivery of therapy for ovarian cancer, are also outlined.
Solar Power Can Substantially Prolong Maximum Achievable Airtime of Quadcopter Drones
Authors: Lin Ching‐Fuh , Lin Ta‐Jung , Liao Wei‐Sheng , Lan Hsiang , Lin Jiun‐Yu , Chiu Chi‐Han , Danner Aaron
Published: August 2020

Sunlight energy is potentially excellent for small drones, which can often operate during daylight hours and fly high enough to avoid cloud blockade. However, the best solar cells provide limited power, compared to conventional power sources, making their use for aerial vehicles difficult to realize, especially in rotorcraft where significant lift ordinarily generated by a wing is already sacrificed for the ability to hover. In recent years, advances in materials (use of carbon‐fiber components, improvement in specific solar cells and motors) have finally brought solar rotorcraft within reach. Here, the application is explored through a concise mathematical model of solar rotorcraft based on the limits of solar power generation and motor power consumption. Multiple solar quadcopters based on this model with majority solar power are described. One of them has achieved an outdoor airtime over 3 hours, 48 times longer than it can last on just battery alone with the solar cells carried as dead weight and representing a significant prolongation of drone operation. Solar‐power fluctuations during long flight and their interaction with power requirements are experimentally characterized. The general conclusion is that solar cells have reached high enough efficiencies and can outperform batteries under the right conditions for quadcopters.
ZnO–Ti3C2 MXene Electron Transport Layer for High External Quantum Efficiency Perovskite Nanocrystal Light‐Emitting Diodes
Authors: Lu Po , Wu Jinlei , Shen Xinyu , Gao Xupeng , Shi Zhifeng , Lu Min , Yu William W. , Zhang Yu
Published: August 2020

2D transition metal carbides, nitrides, and carbonitrides called MXenes show outstanding performance in many applications due to their superior physical and chemical properties. Herein, a ZnO–MXene mixture with different contents of Ti3C2 is applied as electron transport layers (ETLs) and the influence of the Ti3C2 MXene in all‐inorganic metal halide perovskite nanocrystal light‐emitting diodes (perovskite NC LEDs) is explored. The addition of Ti3C2 makes more balanced charge carrier transport in LEDs by changing the energy level structure and electron mobility of ETL. Moreover, lower surface roughness is obtained for the ETL, thus guaranteeing uniform distribution of the perovskite NCs layer and further reducing leakage current. As a result, a 17.4% external quantum efficiency (EQE) with low efficiency roll‐off is achieved with 10% Ti3C2, which is a 22.5% improvement compared to LEDs without Ti3C2.
Controlling Defect Formation of Nanoscale AlN: Toward Efficient Current Conduction of Ultrawide‐Bandgap Semiconductors
Authors: Wu Yuanpeng , Laleyan David A. , Deng Zihao , Ahn Chihyo , Aiello Anthony F. , Pandey Ayush , Liu Xianhe , Wang Ping , Sun Kai , Ahmadi Elaheh , Sun Yi , Kira Mackillo , Bhattacharya Pallab K. , Kioupakis Emmanouil , Mi Zetian
Published: August 2020

Ultrawide‐bandgap semiconductors such as AlN, BN, and diamond hold tremendous promise for high‐efficiency deep‐ultraviolet optoelectronics and high‐power/frequency electronics, but their practical application has been limited by poor current conduction. Through a combined theoretical and experimental study, it is shown that a critical challenge can be addressed for AlN nanostructures by using N‐rich epitaxy. Under N‐rich conditions, the p‐type Al‐substitutional Mg‐dopant formation energy is significantly reduced by 2 eV, whereas the formation energy for N‐vacancy related compensating defects is increased by ≈3 eV, both of which are essential to achieve high hole concentrations of AlN. Detailed analysis of the current−voltage characteristics of AlN p‐i‐n diodes suggests that current conduction is dominated by hole‐carrier tunneling at room temperature, which is directly related to the activation energy of Mg dopants. At high Mg concentrations, the dispersion of Mg acceptor energy levels leads to drastically reduced activation energy for a portion of Mg dopants, evidenced by the small tunneling energy of 67 meV, which explains the efficient current conduction and the very small turn‐on voltage (≈5 V) for the diodes made of nanoscale AlN. This work shows that nanostructures can overcome the dopability challenges of ultrawide‐bandgap semiconductors and significantly increase the efficiency of devices.
Current‐Induced Planar Resistive Switching Mediated by Oxygen Migration in NiO/Pt Bilayer
Authors: Hu Shuai , Yang Huanglin , Tang Meng , Chen Huanjian , Yang Yumeng , Zhou Shiming , Qiu Xuepeng
Published: August 2020

New materials and mechanisms to retain electrically tunable resistance states are highly pursed to advance information technology. In this study, a novel scenario of current‐induced planar resistive switching mediated by oxygen migration is unveiled in the NiO/Pt bilayers. Sawtooth‐like switching is successfully realized in various crystalline NiO, and the switching amplitude monotonically increases with the Pt thickness. On the other hand, the critical switching current is found to be strongly correlated with the substrate thermal conductivity hence suggesting a thermal origin. By directly probing the Ni2+ and O2− distribution before and after switching via electron energy loss spectrum, the switching behavior in NiO/Pt is assuredly associated with the planar redistribution of O2−, thereby setting forth an oxygen migration scenario underlying the switching process. Under this scenario, the planar resistive switching is extended to the SrTiO3/Pt, GdOx/Pt, and TbOx/Pt, and the manipulation of the switching characteristics is successfully achieved by controlling the oxygen content in the GdOx/Pt and TbOx/Pt bilayers. The results offer novel strategy to design new emergent memory devices through oxygen mediated planar resistive switching.
Using statistical learning algorithms to predict cover crop biomass and cover crop nitrogen content
Authors: Marcillo Guillermo S. , Mirsky Steven , Poncet Aurelie , Reberg‐Horton Chris , Timlin Dennis , Schomberg Harry , Ramos Paula
Published: August 2020

Cereal rye (Secale cereale sp.) is a cover crop species known to improve soil and water quality. Late‐season biomass production is information growers need to maximize cover crop benefits and schedule field operations. Statistical learning, built upon statistical and computational algorithms that “learn” from data, may help to improve predictions of cover crop biomass as a function of initial soil inorganic nitrogen levels. Three models—Least Absolute Shrinkage and Selection Operator (LASSO), Ridge, and Random Forest (RF)—were trained and optimized on a 3‐yr allometric and remote sensing dataset of cereal rye responses to N fertilization in the mid‐Atlantic northern and southeastern United States. Shoot biomass (mean, 9,800 kg ha−1) was accurately predicted with a RF model (RMSE, 2,039 kg ha−1). Targeting shoot N content (mean, 107 kg ha−1), on the other hand, LASSO made accurate and more stable predictions (RMSE, 34 kg ha−1). Early‐season information (cover crop C/N ratio, tiller counts, and ground‐sensed normalized difference vegetation index) contributed to enhancing biomass and N content predictions. A final test on untrained data revealed that 92 and 73% of the predictions from either algorithm corresponded to ground‐truthed biomass and shoot N content observed under different N regimes. Modern data‐intensive approaches, such as statistical learning, show promise to characterize end‐season performance of a cover crop and may contribute to better farm decision‐making.
Fetal brain ultrasound measures and maternal nutrition: A feasibility study in Ecuador
Authors: Sibbald Carrie A. , Nicholas Jennifer L. , Chapnick Melissa , Ross Naima , Gandor Patricia L. , Waters William F. , Palacios Iván , Iannotti Lora L.
Published: August 2020

Objective

Nutrition during pregnancy is an important modifiable determinant of fetal growth and development. This pilot study aimed to characterize the association between fetal anthropometry, fetal brain development, and maternal diet among women in Ecuador using portable ultrasound in resource‐limited clinics, including measurements of brain structures not typically imaged in this setting.

Methods

Pregnant women (n = 47) from four resource‐limited health centers were surveyed on demographic, socioeconomic, morbidity, and dietary information. Maternal height, weight, and blood pressure were taken. A sonographer took 15 images per participant, including those standardly assessed during the fetal survey and additional brain structures identified as potentially responsive to maternal nutrition, but not part of the standard fetal survey.

Results

Mean percentiles for all standard fetal survey measurements generated from WHO Fetal Growth Curves fell below 50%, and negative meanZscores were found for biparietal diameter (−0.95 ± 1.11) and femur length (−0.22 ± 1.10). Generalized linear modeling adjusting for gestational age and other covariates showed frequency of seafood consumption was positively associated with fetal biparietal diameterZscore (P= 0.005), beans and legumes positively associated with femur length (P= 0.006), and a negative association was found for soda consumption and fetal head circumference (P= 0.013).

Conclusions

This pilot study demonstrated the feasibility of capturing images of nutrition‐relevant fetal brain structures not part of the standard fetal survey in resource‐limited settings using portable ultrasound. Our study revealed associations between anthropometry, brain structure size, and maternal diet demonstrating potential for prenatal nutrition research using ultrasound in the field.
Prenatal genetic diagnosis of cranioectodermal dysplasia in a Polish family with compound heterozygous variants in WDR35
Authors: Walczak‐Sztulpa Joanna , Wawrocka Anna , Leszczynska Beata , Mikulska Boyana , Arts Heleen H. , Bukowska‐Olech Ewelina , Daniel Maria , Krawczynski Maciej R. , Latos‐Bielenska Anna , Obersztyn Ewa
Published: August 2020

The ciliary chondrodysplasias represent a group of clinically and genetically heterogeneous disorders that affect skeleton development. Cilia are organelles that project from the surface of many cell types and play an important role during prenatal and postnatal human development. Cranioectodermal dysplasia (Sensenbrenner syndrome, CED) is a ciliopathy primarily characterized by craniofacial, skeletal, and ectodermal abnormalities. To date six genes have been associated with CED: IFT122, WDR35, WDR19, IFT140, IFT43, and IFT52. Prenatal diagnosis of CED is challenging, and genetic testing can facilitate making a correct diagnosis. Here, we report on a family with two male siblings affected by CED: a 3.5 year‐old patient and his 2 year‐old brother. Molecular analysis of the proband at 1 year of age revealed compound heterozygous variants in WDR35: c.3G>A [p.(Met1‐Ala30delinsMetfsTer4)] and c.2522A>T [p.(Asp841Val)]. Ultrasound examination during the second pregnancy revealed an increased nuchal translucency of 4.5 mm and a hypoplastic nasal bone at 12 weeks of gestation. Prenatal diagnostic testing was offered because of an increased risk for chromosomal abnormalities and recurrence risk for CED. Prenatal genetic analysis of a chorionic villus sample detected the WDR35 variants previously identified in the elder brother. This is the first report of a prenatal genetic diagnosis in CED.
A founder RAB27A variant causes Griscelli syndrome type 2 with phenotypic heterogeneity in Qatari families
Authors: Al‐Sulaiman Reem , Othman Amna , El‐Akouri Karen , Fareed Shehab , AlMulla Hajer , Sukik Aseel , Al‐Mureikhi Mariam , Shahbeck Noora , Ali Rehab , Al‐Mesaifri Fatma , Musa Sara , Al‐Mulla Mariam , Ibrahim Khalid , Mohamed Khalid , Al‐Nesef Maryam Ali , Ehlayel Mohammad , Ben‐Omran Tawfeg
Published: August 2020

Griscelli syndrome type 2 (GS2) is a rare autosomal recessive disorder caused by pathogenic variants in the RAB27A gene and characterized by partial albinism, immunodeficiency, and occasional hematological and neurological involvement. We reviewed and analyzed the medical records of 12 individuals with GS2 from six families belonging to a highly consanguineous Qatari tribe and with a recurrent pathogenic variant in the RAB27A gene (NM_004580.4: c.244C > T, p.Arg82Cys). Detailed demographic, clinical, and molecular data were collected. Cutaneous manifestations were the most common presentation (42%), followed by neurological abnormalities (33%) and immunodeficiency (25%). The most severe manifestation was HLH (33%). Among the 12 patients, three patients (25%) underwent HSCT, and four (33%) died. The cause of death in all four patients was deemed HLH, providing evidence for this complication's fatal nature. Interestingly, two affected patients (16%) were asymptomatic. This report highlights the broad spectrum of clinical presentations of GS2 associated with a founder variant in the RAB27A gene (c.244C > T, p.Arg82Cys). Early suspicion of GS2 among Qatari patients with cutaneous manifestations, neurological findings, immunodeficiency, and HLH would shorten the diagnostic odyssey, guide early and appropriate treatment, and prevent fatal outcomes.
A polygenic risk score analysis of ASD and ADHD across emotion recognition subtypes
Authors: Waddington Francesca , Franke Barbara , Hartman Catharina , Buitelaar Jan K. , Rommelse Nanda , Mota Nina Roth
Published: August 2020

This study investigated the genetic components of ADHD and ASD by examining the cross‐disorder trait of emotion recognition problems. The genetic burden for ADHD and ASD on previously identified emotion recognition factors (speed and accuracy of visual and auditory emotion recognition) and classes (Class 1: Average visual, impulsive auditory; Class 2: Average‐strong visual & auditory; Class 3: Impulsive & imprecise visual, average auditory; Class 4: Weak visual & auditory) was assessed using ASD and ADHD polygenic risk scores (PRS). Our sample contained 552 participants: 74 with ADHD, 85 with ASD, 60 with ASD + ADHD, 177 unaffected siblings of ADHD or ASD probands, and 156 controls. ADHD‐ and ASD‐PRS, calculated from the latest ADHD and ASD GWAS meta‐analyses, were analyzed across these emotion recognition factors and classes using linear mixed models. Unexpectedly, the analysis of emotion recognition factors showed higher ASD‐PRS to be associated with faster visual emotion recognition. The categorical analysis of emotion recognition classes showed ASD‐PRS to be reduced in Class 3 compared to the other classes (p value threshold [pT] = 1, p = .021). A dimensional analysis identified a high ADHD‐PRS reduced the probability of being assigned to the Class 1 or Class 3 (pT = .05, p = .028 and p = .044, respectively). Though these nominally significant results did not pass FDR correction, they potentially indicate different indirect causative chains from genetics via emotion recognition to ADHD and ASD, which need to be verified in future research.
Ophthalmic genetics in South America
Authors: Daich Varela Malena , Moya Rene , Schlottmann Patricio G. , Hufnagel Robert B. , Arberas Claudia , Fernández Federico M. , Inga M. Eugenia , Lores Juliana , Pachajoa Harry , Prada Carlos E. , Sallum Juliana M. Ferraz
Published: August 2020

South America comprises of heterogeneous topographies, populations, and health care systems. Therefore, it is not surprising to see differences among the countries regarding expertise, education, and practices of ophthalmic genetics for patients with rare eye diseases. Nevertheless, common challenges such as limited genetics training in medical schools and among ophthalmologists, scarcity of diagnostic tools for phenotyping, and expensive genetic testing not covered by the public healthcare systems, are seen in all of them. Here, we provide a detailed report of the current status of ophthalmic genetics, described by the personal views of local ophthalmologists from Brazil, Colombia, Argentina, and Chile. By reporting our strengths and weaknesses as a region, we intend to highlight the need for guidelines on how to manage these patients aligned with public health policies. Our region contributes to research worldwide, with thousands of well diagnosed patients from a number of unique and genetically diverse populations. The constant expansion of ophthalmic genetics and molecular diagnostics requires us to join forces to collaborate across South America and with other countries to improve access to next‐generation diagnostics and ultimately improve patient care.
Contrasting the ancestry patterns of three distinct population groups from the northernmost region of South America
Authors: Mogollón Olivares Fernanda , Moncada Madero Julie , Casas‐Vargas Andrea , Zea Montoya Sara , Suárez Medellín Dayana , Gusmão Leonor , Usaquén William
Published: August 2020

Colombia, located in the north of the South American subcontinent is a country of great interest for population genetic studies given its high ethnic and cultural diversity represented by the admixed population, 102 indigenous peoples and African descent populations. In this study, an analysis of the genetic structure and ancestry was performed based on 46 ancestry informative INDEL markers (AIM‐INDELs) and considering the genealogical and demographic variables of 451 unrelated individuals belonging to nine Native American, two African American, and four multiple ancestry populations. Measures of genetic diversity, ancestry components, and genetic substructure were analyzed to build a population model typical of the northernmost part of the South American continent. The model suggests three types of populations: Native American, African American, and multiple ancestry. The results support hypotheses posed by other authors about issues like the peopling of South America and the existence of two types of Native American ancestry. This last finding could be crucial for future research on the peopling of Colombia and South America in that a single origin of all indigenous communities should not be assumed. It then would be necessary to consider other events that could explain their genetic variability and complexity throughout the continent.
Does thiamine protect the brain from iron overload and alcohol‐related dementia?
Authors: Listabarth Stephan , König Daniel , Vyssoki Benjamin , Hametner Simon
Published: August 2020

Alcohol‐related dementia (ARD) is a common and severe co‐morbidity in alcohol use disorder (AUD). We propose brain iron overload (BIO) to be an important and previously neglected pathogenic process, accelerating cognitive decline in AUD. Furthermore, we suggest thiamine, which is frequently depleted in AUD, to be a key modulator in this process: Thiamine deficiency impairs the integrity of the blood‐brain barrier, thereby enabling iron to pass through and accumulate in the brain. This hypothesis is based on findings from animal, translational, and neuroimaging studies, discussed in this article. To validate this hypothesis, translational studies focusing on brain iron homeostasis in AUD, as well as prospective clinical studies investigating prevalence and clinical impact of BIO in AUD, should be conducted. If proven right, this would change the understanding of ARD and may lead to novel therapeutic interventions in prevention and treatment of ARD.
Visible‐Light‐Mediated Heterocycle Functionalization via Geometrically Interrupted [2+2] Cycloaddition
Authors: Popescu Mihai V. , Mekereeya Aroonroj , Alegre‐Requena Juan V. , Paton Robert S. , Smith Martin D.
Published: August 2020

The [2+2] photocycloaddition is the most valuable and intensively investigated photochemical process. Here we demonstrate that irradiation of N‐acryloyl heterocycles with blue LED light (440 nm) in the presence of an IrIII complex leads to efficient and high yielding fused γ‐lactam formation across a range of substituted heterocycles. Quantum calculations show that the reaction proceeds via cyclization in the triplet excited state to yield a 1,4‐diradical; intersystem crossing leads preferentially to the closed shell singlet zwitterion. This is geometrically restricted from undergoing recombination to yield a cyclobutane by the planarity of the amide substituent. A prototropic shift leads to the observed bicyclic products in what can be viewed as an interrupted [2+2] cycloaddition.
Probing Cooperativity of N‐Terminal Domain Orientations in the p97 Molecular Machine: Synergy Between NMR Spectroscopy and Cryo‐EM
Authors: Huang Rui , Ripstein Zev A. , Rubinstein John L. , Kay Lewis E.
Published: August 2020

The hexameric p97 enzyme plays an integral role in cellular homeostasis. Large changes to the orientation of its N‐terminal domains (NTDs), corresponding to NTD‐down (p97‐ADP) or NTD‐up (p97‐ATP), accompany ATP hydrolysis. The NTDs in a series of p97 disease mutants interconvert rapidly between up and down conformations when p97 is in the ADP‐bound state. While the populations of up and down NTDs can be determined from bulk measurements, information about the cooperativity of the transition between conformations is lacking. Here we use cryo‐EM to determine populations of the 14 unique up/down NTD states of the homo‐hexameric R95G disease‐causing p97 ring, showing that NTD orientations do not depend on those of neighboring subunits. In contrast, NMR studies establish that inter‐protomer cooperativity is important for regulating the orientation of NTDs in p97 particles comprising mixtures of different subunits, such as wild‐type and R95G, emphasizing the synergy between cryo‐EM and NMR in establishing how the components of p97 function.
Antiproliferative and bactericidal activity of diiron and monoiron cyclopentadienyl carbonyl complexes comprising a vinyl‐aminoalkylidene unit
Authors: Rocco Dalila , Busto Natalia , Pérez‐Arnaiz Cristina , Biancalana Lorenzo , Zacchini Stefano , Pampaloni Guido , Garcia Begoña , Marchetti Fabio
Published: August 2020

A series of diiron complexes with two cyclopentadienyls, two carbonyls, and one bridging vinyl‐aminoalkylidene as ligands, [3a–h]CF3SO3 and [4a–d]CF3SO3, was synthesized in 66–94% yields from diiron μ‐aminocarbyne precursors. The subsequent reactions with pyrrolidine led to selective fragmentation to aminoalkylidene‐ferracyclopentenone derivatives (5a–h and 6a–c) in 30–84% yields. The compounds were characterized by elemental analysis, Fourier transform infrared and NMR spectroscopy, and by single crystal X‐ray diffraction in three cases. The stability in aqueous media relevant to biological trials, the carbon monoxide release, and the catalytic activity in NADH oxidation were evaluated for selected compounds by NMR spectroscopy and gas chromatography. The in vitro antiproliferative activity of the compounds was determined towards cancer (A2780, A2780cisR) and noncancer (HEK‐293) cell lines. Moreover, the antibacterial activity was tested on Gram‐positive (vancomycin‐resistant E. faecium and methicillin‐resistant S. aureus) and Gram‐negative strains (A. baumannii and P. aeruginosa).
Strengthening Student Nurses’ Sense of Belonging Through Attendance at a Professional Nursing Conference
Authors: Kruse Julie A. , Didion Judy , Perzynski Kathy
Published: August 2020

Nursing faculty members at one midwestern college provided a professional development opportunity for baccalaureate nursing students by organizing a trip to a nursing association conference (ie, the AORN Global Surgical Conference & Expo). Preconference and postconference survey results showed a statistically significant increase in sense‐of‐belonging scores; and the eta‐squared statistic (0.14) indicated a large effect size, suggesting the students’ conference attendance enhanced their sense of belonging to the profession. A Pearson's correlation analysis revealed a strong, positive correlation between a student's intention to join a professional organization and his or her belief that membership in a professional organization was important (r = 0.82, n = 26, P < .001). This type of professional experience may improve students’ perception of nursing professionalism, sense of belonging, intention to join a professional organization, and confidence in nursing as a career.
Effect of ionic liquid segments of copolymer on compatibilization process and dielectric behavior of polylactide/polyvinylidene fluoride blends
Authors: Wang Ping , Cui Zhaopei , Hu Xianhai , Xu Pei , Ding Yunsheng
Published: August 2020

Biodegradable polylactide (PLA) and polyvinylidene fluoride (PVDF) blends containing the copolymer of PEGMA and 1‐vinyl‐3‐ethylimidazolium bromide (PMI) were prepared, and the effects of ionic liquid segments of PMI on the compatibility of PLA and PVDF were investigated by dielectric relaxation spectroscopy (DRS). PMI can obviously improve the compatibility of PLA and PVDF, compared with the copolymer of PEGMA and vinyl imidazole (PMV). DRS showed that the compatibility of PLA and PVDF was related to the relaxation behavior of the blends, which was identified with Maxwell‐Wagner‐Sillars (MWS) interfacial polarization. The ε' of PLA/PVDF/PMI blends was much higher than that of PLA/PVDF/PMV blends in the same temperature, resulting from the stimulation of MWS interfacial polarization by the ion mobility of PMI.
Direct laser etching of hierarchical nanospheres on silicon rubber surface with robust dynamic superhydrophobic stability
Authors: Xie Heng , Xu Wenhua , Wu Ting
Published: August 2020

Silicone rubbers with high dynamic superhydrophobic stability have an extensive application prospect. Applying direct laser etching technology, a fast and efficient method is proposed for the preparation of silicone rubber surfaces with hierarchical nanospheres and robust dynamic superhydrophobicity. A 4 μl water droplet on the laser modified silicone rubber surface exhibits a contact angle (CA) of 154 ± 3° and a roll‐off angle (RA) of 5 ± 1°, there is a 65.6% increase in CA compared with the pristine silicon rubber. Moreover, the modified surface can stabilize its superhydrophobic state under a dynamic pressure of 1960.2 Pa. Interestingly, no significant change in the contacting time for the droplets with different impacting speed is found, which means that the stabilized contact time and robust dynamic superhydrophobicity are induced on the modified silicone rubber surface. The self‐cleaning and anti‐icing properties on the modified surface can effectively reduce the damage caused by surface pollution, ice formation, and other natural factors when applied to power lines, sealing elements, and automotive.
Ionic liquids as dispersing agents of graphene nanoplatelets in poly(methyl methacrylate) composites with microwave absorbing properties
Authors: Caldas Camila Mouta , Soares Bluma Guenther , Indrusiak Tamara , Barra Guilherme Mariz Oliveira
Published: August 2020

Graphene nanoplatelets (GNP) is noncovalently functionalized with imidazolium‐, pyridinium‐, and vinyl‐pyridinium‐based ionic liquids containing bromide or bis(trifluoromethyl‐sulfonyl)imide (TFSI) as the counteranions, and used to prepare poly (methyl methacrylate) (PMMA) nanocomposites by solution casting approach followed by compression molding technique. The PMMA composites loaded with 1.9 and 1.8 wt% of GNP in PMMA/GNP composite and PMMA/GNP/ionic liquids, respectively, were characterized by melting viscosity, thermogravimetric analysis and AC electrical conductivity (σAC). The microwave absorption properties at the X‐band (8.2–12.4 GHz) frequency were measured for systems with 1 mm thickness using the metal‐backed configuration. PMMA nanocomposites loaded with GNP/N‐dodecyl‐4‐vinyl‐pyridinium.TFSI (C12ViPy.TFSI) displayed higher thermal stability and higher σAC. This system also presented the best response in terms of microwave absorbing properties, with minimum reflection loss (RL) of around −6 dB at 8.7 GHz. Triple layered composite structures with layers of different conductivities and different stacking orders were also investigated in terms of reflection loss. Broadband absorption with minimum RL ≤ −10 dB (90% of electromagnetic attenuation) in the frequency between 10.2 and 12.4 GHz and better absorbing effectiveness were observed for the PMMA/GNP‐PMMA/GNP/C12ViPy.TFSI‐PMMA/GNP/C12ViPy.Br triple‐layered system with 3 mm thickness.
The capability‐enhancing role of government‐driven industrial districts for new technology‐based firms in South Korea
Authors: Jo Yuri , Chung Won Young , Lee Daeho
Published: August 2020

Government‐driven industrial clusters have attracted considerable attention from academic research as well as practical fields, mainly because of their contributions to regional economic growth and sustainable innovation performance. This article investigates the impact of government‐driven industrial districts on the efficiency of new technology‐based firms in information and communications technology industries. Using a meta‐frontier analysis with a unique Korean start‐up dataset, we find that the government's provision of industrial districts increases firm efficiency level compared with that of others outside the districts. Specifically, being located in industrial districts not only improves the efficiency of individual start‐ups but also positively affects the maximum efficiency levels that firms can achieve. Our findings suggest that locational support by public administration, such as utility infrastructure, tax benefits and inter‐firm informal network opportunities, enhances firms' dynamic capability to search for and combine resources to create new markets and innovations, especially for newly established technology firms.
Vulnerability of the biota in riverine and seasonally flooded habitats to damming of Amazonian rivers
Authors: Latrubesse Edgardo M. , d'Horta Fernando M. , Ribas Camila C. , Wittmann Florian , Zuanon Jansen , Park Edward , Dunne Thomas , Arima Eugenio Y. , Baker Paul A.
Published: August 2020

The extent and intensity of impacts of multiple new dams in the Amazon basin on specific biological groups are potentially large, but still uncertain and need to be better understood.

It is known that river disruption and regulation by dams may affect sediment supplies, river channel migration, floodplain dynamics, and, as a major adverse consequence, are likely to decrease or even suppress ecological connectivity among populations of aquatic organisms and organisms dependent upon seasonally flooded environments.

This article complements our previous results by assessing the relationships between dams, our Dam Environmental Vulnerability Index (DEVI), and the biotic environments threatened by the effects of dams. Because of the cartographic representation of DEVI, it is a useful tool to compare the potential hydrophysical impacts of proposed dams in the Amazon basin with the spatial distribution of biological diversity. As the impact of Amazonian dams on the biota of both rivers and periodically flooded riparian environments is severe, DEVIs from different Amazonian tributary basins are contrasted with patterns of diversity and distribution of fish, flooded forest trees and bird species.

There is a consistent relationship between higher DEVI values and the patterns of higher species richness and endemism in all three biological groups. An assessment of vulnerability at the scale of tributary basins, the assessment of biodiversity patterns related to DEVI, and the analysis of teleconnections at basin scale, demonstrate that recent construction of dams is affecting the biota of the Amazon basin.

The evidence presented here predicts that, if currently planned dams are built without considering the balance between energy production and environmental conservation, their cumulative effects will increase drastically and represent a major threat to Amazonian biodiversity.
Locomotion on the edge: Structural properties of the third metacarpal in Thoroughbred and Quarter Horse racehorses and feral Assateague Island ponies
Authors: Goldstein Deanna M. , Engiles Julie B. , Rezabek Grant B. , Ruff Christopher B.
Published: August 2020

The elongated, distally tapered limbs of horses are adapted for high‐speed locomotion. Because these traits are artificially selected for in modern racehorses, they operate at a morphological extreme with a high risk of fracture. Racehorses are subject to different training and racing regimes depending on their breed and gait, and are therefore an interesting model to examine bone functional adaptation under variable biomechanically intense conditions. This study compares bone structural properties in the third metacarpal (MCIII) of Thoroughbred (n= 9) and Quarter Horse (n= 11) racehorses, using feral Assateague Island ponies (n= 6) as an untrained/unraced outgroup, to determine whether structural properties reflect variable racing and training regimes. Geometric section properties and bone mineral densities were determined using peripheral quantitative CT at two diaphyseal sites and through the distal epiphysis. Diaphyseal strength of the MCIII in all three breeds does not differ relative to body size, but in the mid‐diaphyseal region Thoroughbreds have higher antero‐posterior relative to medio‐lateral bending strength than Quarter Horses, as well as higher bone mineral densities in left MCIII epiphyses (particularly in the lateral condyle). Interestingly, all breeds have lower bone mineral densities in the lateral versus medial condyle, an inherent structural feature that may influence predisposition to fracture when running around turns. Our results suggest that despite subtle differences in bone structure between different racehorse breeds, basic morphology of the third metacarpus is relatively similar among racing and non‐racing horses, possibly reflecting intense selection (natural and artificial) across domestic equids for similar structural features within distal limb elements.
Adaptive stabilization for uncertain hyperbolic PDE‐ODE cascade systems
Authors: Li Xia , Liu Yungang , Li Jian , Man Yongchao
Published: August 2020

This paper is devoted to the adaptive stabilization for uncertain hyperbolic PDE‐ODE cascade systems. Remarkably, unknown spatially varying and unknown constant parameters exist in the PDE and ODE subsystems, respectively. This brings essential difficulties in the design of compensator and boundary controller, and in the involved performance analysis. To solve the control problem, an infinite‐dimensional backstepping transformation (simplified as IDBT) and its inverse are first introduced to change the original system into a new system (called target system). Then, a state‐feedback boundary controller is constructed for the target system by incorporating the adaptive technique based on projection operator, which can guarantee the desirable stability of the resulting closed‐loop system. Finally, a simulation example is provided to illustrate the effectiveness of the proposed adaptive controller.
A Novel Chd8 Mutant Mouse Displays Altered Ultrasonic Vocalizations and Enhanced Motor Coordination
Authors: Hulbert Samuel W. , Wang Xiaoming , Gbadegesin Simisola O. , Xu Qiong , Xu Xiu , Jiang Yong‐Hui
Published: August 2020

Mutations in CHD8 are among the most common autism‐causing genetic defects identified in human genomics studies. Therefore, many labs have attempted to model this disorder by generating mice with mutations in Chd8. Using a gene trap inserted after Exon 31, we created a novel Chd8 mutant mouse (Chd8+/E31T) and characterized its behavior on several different assays thought to have face validity for the human condition, attempting to model both the core symptoms (repetitive behaviors and social communication impairments) and common comorbidities (motor deficits, anxiety, and intellectual disability). We found that Chd8+/E31T mice showed no difference compared to wild‐type mice in amount of self‐grooming, reproducing the negative finding most other studies have reported. Unlike some of the other published lines, Chd8+/E31T mice did not show deficits in the three‐chamber test for social novelty preference. A few studies have examined ultrasonic vocalizations in Chd8 mutant mice, but we are the first to report an increase in call length for adult mice. Additionally, we found that in contrast to previous published lines, Chd8+/E31T mice displayed no anxiety‐like behaviors or learning impairments but showed paradoxically significant improvement in motor function. The inconsistencies in behavioral phenotypes in the Chd8 mutant mice generated by different laboratories poses a challenge for modeling autism spectrum disorder and preclinical studies in mice going forward and warrants further investigation into the molecular consequences of the different mutations in Chd8 and the functional impact on behavior.

Lay Summary

Several different mouse models carrying mutations in the Chd8 gene have been created to study the effects of these autism‐causing mutations in the laboratory. The current study characterizes a novel Chd8 mutant mouse model as well as summarizes data from previously published Chd8 mutant mice. The inconsistencies between different studies are concerning, but future research into the reasons why these inconsistencies occur may help us understand why patients with various mutations have different degrees of symptom severity. Autism Res 2020, 13: 1685–1697. © 2020 International Society for Autism Research and Wiley Periodicals LLC
Optimierungsgestützt entwerfen und bemessen
Authors: Forman Patrick , Gaganelis Georgios , Mark Peter
Published: August 2020

Beton ist frei formbar. Auch Bewehrungen lassen sich beliebig im Raum verlegen. Dennoch wird selten von diesen Möglichkeiten Gebrauch gemacht. Typische Stahlbetonkonstruktionen besitzen rechteckige Grundformen, Bewehrungsnetze parallel der Oberflächen und große Massen. Der Beitrag zeigt, wie mit topologischen Optimierungen kraftflussaffine Betonstrukturen entstehen können. Der Materialverbrauch sinkt dabei rapide. Vorgestellt werden die äußere Formfindung, der Entwurf effektiver Querschnitte und die an Trajektorien orientierte Bewehrungsführung ähnlich bekannter Stabwerkmodelle. Dazu werden die Grundgleichungen der Optimierungsaufgabe abgeleitet, eine baustoffgerechte Steuerung in Richtung von zug‐ oder druckspannungsdominantem Tragverhalten eingeführt und Grundaspekte zur Sicherung der Robustheit erläutert. Zahlreiche Beispiele zeigen die Anwendung für Brücken, Pylone, Schalen, Balken, Trägerroste oder Auflagerdetails und verdeutlichen das enorme Potenzial für eine tiefgreifende Materialreduktion in der Betonbauweise.