bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of a mitochondrial ATP synthase with bound native cardiolipin
Authors: Mühleip Alexander , McComas Sarah E , Amunts Alexey
Published: November 2019

The mitochondrial ATP synthase fuels eukaryotic cells with chemical energy. Here we report the cryo-EM structure of a divergent ATP synthase dimer from mitochondria of Euglena gracilis, a member of the phylum Euglenozoa that also includes human parasites. It features 29 different subunits, 8 of which are newly identified. The membrane region was determined to 2.8 Å resolution, enabling the identification of 37 associated lipids, including 25 cardiolipins, which provides insight into protein-lipid interactions and their functional roles. The rotor-stator interface comprises four membrane-embedded horizontal helices, including a distinct subunit a. The dimer interface is formed entirely by phylum-specific components, and a peripherally associated subcomplex contributes to the membrane curvature. The central and peripheral stalks directly interact with each other. Last, the ATPase inhibitory factor 1 (IF1) binds in a mode that is different from human, but conserved in Trypanosomatids.
A stochastic framework of neurogenesis underlies the assembly of neocortical cytoarchitecture
Authors: Llorca Alfredo , Ciceri Gabriele , Beattie Robert , Wong Fong Kuan , Diana Giovanni , Serafeimidou-Pouliou Eleni , Fernández-Otero Marian , Streicher Carmen , Arnold Sebastian J , Meyer Martin , Hippenmeyer Simon , Maravall Miguel , Marin Oscar
Published: November 2019

The cerebral cortex contains multiple areas with distinctive cytoarchitectonic patterns, but the cellular mechanisms underlying the emergence of this diversity remain unclear. Here, we have investigated the neuronal output of individual progenitor cells in the developing mouse neocortex using a combination of methods that together circumvent the biases and limitations of individual approaches. Our experimental results indicate that progenitor cells generate pyramidal cell lineages with a wide range of sizes and laminar configurations. Mathematical modeling indicates that these outcomes are compatible with a stochastic model of cortical neurogenesis in which progenitor cells undergo a series of probabilistic decisions that lead to the specification of very heterogeneous progenies. Our findings support a mechanism for cortical neurogenesis whose flexibility would make it capable to generate the diverse cytoarchitectures that characterize distinct neocortical areas.
Host dietary specialization and neutral assembly shape gut bacterial communities of wild dragonflies
Authors: Deb Rittik , Nair Ashwin , Agashe Deepa
Published: November 2019

Host-associated gut microbiota can have significant impacts on host ecology and evolution and are often host-specific. Multiple factors can contribute to such host-specificity: (1) host dietary specialization passively determining microbial colonization, (2) hosts selecting for specific diet-acquired microbiota, or (3) a combination of both. The latter possibilities indicate a functional association and should produce stable microbiota. We tested these alternatives by analyzing the gut bacterial communities of six species of wild adult dragonfly populations collected across several geographic locations. The bacterial community composition was predominantly explained by sampling location, and only secondarily by host identity. To distinguish the role of host dietary specialization and host-imposed selection, we identified prey in the guts of three dragonfly species. Surprisingly, the dragonflies–considered to be generalist predators–consumed distinct prey; and the prey diversity was strongly correlated with the gut bacterial profile. Such host dietary specialization and spatial variation in bacterial communities suggested passive rather than selective underlying processes. Indeed, the abundance and distribution of 72% of bacterial taxa were consistent with neutral community assembly; and fluorescent in situ hybridization revealed that bacteria only rarely colonized the gut lining. Our results contradict the expectation that host-imposed selection shapes the gut microbiota of most insects, and highlight the importance of joint analyses of diet and gut microbiota of natural host populations.
Optimization of Aspergillus niger α-amylase Activity for Enhanced Glucose Production from Cassava Starch
Authors: Osaribie N. A. , Ndubuisi J. C. , Ewa O. , Karimah M. R. , Oda O.
Published: November 2019

The aim of this study was to optimize the hydrolytic activity of A. niger α-amylase on cassava starch. Isolation of Aspergillus niger, determination of α-amylase activity, α-amylase production and extraction were performed using standard protocols. Parameters such as pH, temperature, substrate concentration were studied using unifactorial approach. pH was varied from 3.6-5.6, temperature 30-80ºC, substrate concentration 0.3-1.5 g/l. In conclusion, for optimal utilization of α-amylase in the production of numerous products of economic significance, the outcome of this work can be relied upon to boost production of glucose and accessory products from starch.
Organization of Mathematics in the Application of Computers in the First Cycle of the Reformed Primary School
Authors: Mićanović Veselin , Labović Milica
Published: November 2019

The informational age and the age of knowledge that developed the developed countries and slowly touched upon, and the rest of the world implied that human society evolves into a knowledge society where knowledge is considered to be the most valuable resource of the human race. The future will definitely be determined by man's ability to use this knowledge effectively. Technological progress implies different and growing expectations from those who use them, exposing such education to increasing pressures and demands from the environment. Now it is imperative for educational institutions to develop in their student's such knowledge, skills, skills and skills as are required in the environment. The increasing role and importance of information and communication technologies in human society are undoubtedly one of the most important characteristics of today's world. ICT (Information and Communication Technologies) is incorporated into all levels of human organizational activities and has largely influenced communication among people. For this reason, the quality of school work and its direct product the quality of students' knowledge is an essential active and continuous use of ICT in the teaching process.
QSAR, Docking Study of Isatin Analogues as Anti-bacterial Agents for Design New Compounds
Authors: Sabet Razieh , Jafroudi Isar
Published: November 2019

Computational chemistry is unique method in drug discovery which reduce cost. In this study 86 molecules containing isatin core were subjected to quantitative structure-activity relationship analysis and docking study to find the structure requirements for ligand binding. The structures were sketched and optimized in Hyperchem. The structural invariants used in this study were those obtained from whole molecular structures: by both hyperchem and dragon software (16 types of descriptors). Four chemometrics methods including MLR, FA-MLR, PCR and GA-PLS were employed to make connection between structural parameters and anticancer effects. MLR analysis explained the positive effect of the number of urea derivatives, thio urea, amide, thioamide, hydrazone, thiocarbohydrazone, nBnz with the halogen substitution on 5 position of isatin ring on the antimicrobial activity. It also shows nArCN, nPyridines have negative effects on the antimicrobial activity of studied compound.

The FA-MLR describes the effect of 3D-MORSE and Galvez Topological charge descriptors and on antimicrobial activity of the studied compounds. The quality of PCRA equation is better than those derived from FA-MLR. A comparison between the different statistical methods employed revealed that GA-PLS represented superior results and it could explain and predict 73% and 68% of variances in the –LogMIC data, respectively. Comparison between QSAR and docking analysis revealed that by decreasing in number of ring and lipophilicity (also Logp) for design of new compounds can have better activity. Substitutions such as urea, thiourea, thiocarbohydrazone, benzhydrazide as on isatin ring, can cause better interaction with receptor.
Optimal stimulation toward the dermal papilla lineage can be promoted by combined use of osteogenic and adipogenic inducers
Authors: Kazi Taheruzzaman , Niibe Ichitaro , Nishikawa Akio , Matsuzaki Takashi
Published: November 2019

Dermal papilla cells (DPCs) play crucial roles in hair regeneration, but they readily lose their hair‐forming ability during in vitro culture. Although the formation of spheroids partially restores the ability, shrinkage of the spheroids makes it difficult to maintain cellular viability. To address this problem, we stimulated DPCs with factors known to induce adipogenic and/or osteogenic differentiation, because DPCs share unique gene expression profiles with adipocytes and osteocytes. We isolated DPCs from versican (vcan)–GFP mice, in which GFP is expressed under the control of a vcan promoter, which is strongly active in DPCs of anagen hair follicles. GFP fluorescence was most intense when the spheroids were made from DPCs cultured in a half‐diluted combination of adipogenic and osteogenic media (CAO1/2), a Dulbecco’s modified Eagle’s medium‐based medium that contains 10% FBS, 275 nm dexamethasone, 2.5 mm β‐glycerol phosphate, 12.5 µg·mL−1 ascorbic acid, 0.125 µm isobutylmethylxanthine and 2.5 ng·mL−1 insulin. The dose of each additive used was less than the optimal dose for adipogenic or osteogenic differentiation, and shrinkage of the spheroids was avoided through the addition of fibroblast growth factor 2 and platelet‐derived growth factor‐AA to  CAO1/2. In addition, the gene and protein expression of vcan, osteopontin, alkaline phosphatase and α‐smooth muscle actin in the spheroids were augmented to levels similar to those of the intact dermal papillae, which exhibited restored hair‐forming activity. In conclusion, a combination of certain adipogenic and osteogenic inducers, together with fibroblast growth factor 2 and platelet‐derived growth factor‐AA, can promote differentiation toward the DPC lineage.
Stalactite Plot
Authors: Atkinson Anthony C. , Riani Marco
Published: November 2019

This is a line‐printer graphic for exhibiting outliers in multivariate data. It is based on a robust procedure, the forward search. The article contrasts the stalactite plot with more modern plots for the same purpose that use the power and versatility of contemporary computer graphics.
Estimation: General Aspects
Authors: Bedrick Edward J.
Published: November 2019

This entry is concerned with the relationship between sample data and the probability distribution (, which is supposed to have generated them. The estimation of using an empirically derived distribution is discussed along with specific estimators such as the sample mean, the sample median, and a histogram. Estimation by the method of moments, minimum least squares, and least absolute errors are explained, as are the concepts of bias, mean square error, and sufficiency.
Markov Chain Monte Carlo
Authors: Ekvall Karl Oskar , Jones Galin L.
Published: November 2019

Practically relevant statistical models often give rise to probability distributions that are analytically intractable. Fortunately, we now have a collection of algorithms, known as
Markov chain Monte Carlo (MCMC)
, that has brought many of these models within our computational reach. MCMC is a simulation technique that allows us to make (approximate) draws from complex, high‐dimensional probability distributions. A staggering amount of research has been done on both the theoretical and applied aspects of MCMC. This article does not intend to be a complete overview of MCMC but only hopes to get the reader started in the right direction. To this end, this article begins with a general description of the types of problems that necessitate the use of MCMC. It then introduces the fundamental algorithms and addresses some general implementation issues.
Electricity Price Forecasting
Authors: Maciejowska Katarzyna , Weron Rafał
Published: November 2019

Electricity price forecasting (EPF) is an actively developing research field, which aims at predicting the spot and forward prices in wholesale electricity markets. Since day‐ahead forecasting has gained the most attention, in this article we review the modeling approaches for short‐term predictions, with a particular focus on variable selection.
Superimposed Renewal Processes in Reliability
Authors: Wu Shaomin
Published: November 2019

This article reviews the existing literature on the superimposed renewal process, with its foci on probabilistic and statistical properties, statistical inference, and applications in reliability analysis and maintenance policy optimization. It then proposes future research topics.
Diet quality and chronic axonal polyneuropathy: a population‐based study
Authors: Taams Noor E. , Voortman Trudy , Hanewinckel Rens , Drenthen Judith , van Doorn Pieter A. , Ikram Mohammad A.
Published: November 2019

Objective

To investigate the association between diet quality and chronic axonal polyneuropathy.

Methods

Between June 2013 and January 2017, among 1650 participants of the Rotterdam Study (median age 69.1 years, 54.2% women), diet quality was quantified based on food frequency questionnaires as a sum score of adherence (yes/no) to 14 components of the Dutch dietary guidelines. Presence of polyneuropathy was determined based on a questionnaire, neurological examination of the legs, and nerve conduction studies. We used logistic regression to associate diet quality with the presence of chronic axonal polyneuropathy and linear regression to associate with sural sensory nerve action potential (SNAP) amplitude in participants without polyneuropathy. Results were adjusted for age, sex, time between measurements, body mass index, blood pressure, diabetes mellitus, smoking, kidney function, and education.

Results

Overall diet quality was not associated with chronic axonal polyneuropathy (odds ratio [OR] = 0.99, 95% confidence interval [CI] 0.88; 1.12, P = 0.842), nor with sural SNAP amplitude in participants without polyneuropathy (difference = 0.01, 95% CI −0.14; 0.15, P = 0.993). Although not surviving multiple testing, a nominally significant association was found between salt intake ≤6 g/day and presence of chronic axonal polyneuropathy (OR = 0.55, 95% CI 0.35; 0.86, P = 0.008).

Interpretation

We did not find an association between diet quality and chronic axonal polyneuropathy.
Gas Sensing of NiO‐SCCNT Core–Shell Heterostructures: Optimization by Radial Modulation of the Hole‐Accumulation Layer
Authors: Raza Muhammad Hamid , Movlaee Kaveh , Leonardi Salvatore Gianluca , Barsan Nicolae , Neri Giovanni , Pinna Nicola
Published: November 2019

Hierarchical core–shell (C–S) heterostructures composed of a NiO shell deposited onto stacked‐cup carbon nanotubes (SCCNTs) are synthesized by atomic layer deposition (ALD). A film of NiO particles (0.80–21.8 nm in thickness) is uniformly deposited onto the inner and outer walls of the SCCNTs. The electrical resistance of the samples is found to increase of many orders of magnitude with the increasing of the NiO thickness. The response of NiO–SCCNT sensors toward low concentrations of acetone and ethanol at 200 °C is studied. The sensing mechanism is based on the modulation of the hole‐accumulation region in the NiO shell layer upon chemisorption of the reducing gas molecules. The electrical conduction mechanism is further studied by the incorporation of an Al2O3 dielectric layer at NiO and SCCNT interfaces. The investigations on NiO–Al2O3–SCCNT, Al2O3–SCCNT, and NiO–SCCNT coaxial heterostructures reveal that the sensing mechanism is strictly related to the NiO shell layer. The remarkable performance of the NiO–SCCNT sensors toward acetone and ethanol benefits from the conformal coating by ALD, large surface area of the SCCNTs, and the optimized p‐NiO shell layer thickness followed by the radial modulation of the space‐charge region.
Ultralong‐Life Chloride Ion Batteries Achieved by the Synergistic Contribution of Intralayer Metals in Layered Double Hydroxides
Authors: Yin Qing , Luo Jianeng , Zhang Jian , Zhang Shuoxiao , Han Jingbin , Lin Yanjun , Zhou Jisheng , Zheng Lirong , Wei Min
Published: November 2019

Chloride ion batteries (CIBs) are a promising type of energy storage device due to their high theoretical volumetric energy density and abundant reserves of chlorine‐containing precursors. However, the unsatisfactory cycling performance and structural instability of cathode materials hinder their practical application. In this work, layered double hydroxides (LDHs), which consist of a trimetallic NiVAl hydroxide host matrix and interlayer Cl−, are demonstrated to be high‐performance cathode materials for CIBs. The Ni2V0.9Al0.1‐Cl LDH is capable of delivering a high initial capacity of 312.2 mAh g−1 at 200 mA g−1 and an ultralong life over 1000 cycles (with a capacity higher than 113.8 mAh g−1). Such a long cycling life exceeds that of any reported CIBs. The remarkable Cl−‐storage performance of the Ni2V0.9Al0.1‐Cl LDH is ascribed to the synergetic contributions from Vm+ (high redox activity), Ni2+ (favorable electronic structure), and inactive Al3+ (enhances the structural stability), which is revealed by a comprehensive study that utilizes synchrotron X‐ray absorption near‐edge structure experiments, kinetic investigations, and theoretical calculations. This study provides an effective strategy to achieve superior rechargeable batteries, which are applicable to large‐scale energy storage and power grids.
Well‐Controlled Decomposition of Copper Complex Inks Enabled by Metal Nanowire Networks for Highly Compact, Conductive, and Flexible Copper Films
Authors: Zhang Bowen , Chen Chuantong , Li Wanli , Yeom Jeyun , Suganuma Katsuaki
Published: November 2019

Highly compact and conductive Cu films are successfully fabricated by introducing mechanically robust and highly conductive metal nanowires (NWs) as fillers and optimizing amine‐based ligands in Cu complex inks. The metal NWs (AgNWs and CuNWs) dispersed in the complex inks provide networks of nucleation sites for the in situ formed Cu particles and thereby control the decomposition of Cu complex inks at low temperatures to realize Cu films with high uniformity and integrality. The high affinity between metal NWs and the in situ formed Cu element enables the growth of Cu particles along the metal NWs to create a compact structure. Besides, the amine‐based ligands such as 2‐amino‐2‐methyl‐1‐propanol (AMP), 2‐ethylhexylamine (Ethy), and hexylamine (Hexy) are varied to adjust the size of Cu particles and further improve the microstructure and conductivity of the sintered Cu films. The Cu‐Ethy complex/metal NW inks sintered at 140 °C exhibit the lowest resistivity of 14.9 µΩ cm, which is about one‐third that fabricated from the pure Cu‐AMP complex inks. The flexible light‐emitting diode circuits and V‐shaped dipole antennas prepared from the Cu complex/metal NW inks have excellent performance due to their outstanding conductivity and flexibility, showing great potential in the fabrication of cost‐effective, flexible printed electronic devices.
Postdeposition Ligand Exchange Allows Tuning the Transport Properties of Large‐Scale CuInSe2 Quantum Dot Solids
Authors: Gorris Friederieke E. S. , Deffner Michael , Priyadarshi Shekhar , Klinke Christian , Weller Horst , Lange Holger
Published: November 2019

Colloidal quantum dots assembled into quantum dot solids usually suffer from poor conductivity. The most common charge transport mechanism through the solid is hopping transport where the hopping probability depends on the barrier type (stabilizing/connecting ligand molecule) and the interparticle distance. It is demonstrated that the electronic structure of the ligand molecule strongly alters the transport behavior through CuInSe2 quantum dot solids. Transport measurements and optical‐pump terahertz‐probe experiments after a ligand exchange to fully conjugated molecules show an increase of the conductivity by orders of magnitude, as well as a change of the hopping transport mechanism. This change is not due to a reduced interparticle distance, but the electronic structure: the obtained frequency‐dependent complex conductivities point toward an efficient hole transport enabled by an alignment of the quantum dot valence bands and ligand states.
Efficiency Enhancement of All‐Solution‐Processed Inverted‐Structure Green Quantum Dot Light‐Emitting Diodes Via Partial Ligand Exchange with Thiophenol Derivatives Having Negative Dipole Moment
Authors: Moon Hyungsuk , Chae Heeyeop
Published: November 2019

Thiophenol derivatives having a negative dipole moment such as thiophenol (TP), 4‐methylthiophenol (4‐MTP), and 4‐(dimethylamino)thiophenol (4‐DMATP) are incorporated into quantum dots (QDs) and the efficiency of all‐solution‐processed inverted‐structure quantum dot light‐emitting diodes (QLEDs) is enhanced. The negative dipole moments of TP, 4‐MTP, and 4‐DMATP are attributed to the enhancement of the efficiency of the QLEDs. The valence band maximum (VBM) of the QDs is upshifted, and the energy gap between the VBM and the highest molecular orbital level of the hole transport layer is reduced to −0.16 from 0.46 eV by the negative dipole moment of thiophenol derivatives. The electron and hole transport of the QDs are accelerated, and charge balance is achieved at 5 V with a reduction of 1.25 V by the thiophenol derivatives. The QLEDs with 4‐DMATP exhibit a maximum luminance of 106 400 cd m−2, a maximum current efficiency of 98.2 cd A−1, and an external quantum efficiency (EQE) of 24.8%. The EQE of 24.8% is the highest value reported thus far for all‐solution‐processed inverted‐structure single‐device QLEDs, to the best of knowledge. Improvement by factors of 2.99, 1.57, and 1.54 are achieved in the maximum luminescence, maximum current efficiency, and EQE respectively, compared with a QLED with OA ligands.
Factors that Limit Continuous‐Wave Lasing in Hybrid Perovskite Semiconductors
Authors: Jia Yufei , Kerner Ross A. , Grede Alex J. , Rand Barry P. , Giebink Noel C.
Published: November 2019

Metal halide perovskites are a promising platform for solution‐processed semiconductor lasers but have so far only achieved continuous‐wave (cw) operation at low temperature. Here, the origin of this limitation is investigated in prototypical methylammonium lead iodide (MAPbI3) distributed feedback (DFB) lasers and is found to stem from a combination of pump‐induced heating and the accumulation of photoinduced defects. A temperature rise of more than 30 K in the first few hundred ns following pump turn‐on is observed, which leads to a dynamic increase in threshold owing to the strong temperature dependence of stimulated emission in MAPbI3 thin films. In parallel, it is found that the Shockley–Read–Hall rate coefficient increases by an order of magnitude on a similar timescale, suppressing the carrier density generated by the pump. The combined impact of both effects is understood using a comprehensive model that quantitatively explains the duration of lasing as a function of pump intensity and predicts that the threshold of current DFB lasers must be decreased by an order of magnitude to achieve cw operation at room temperature.
Machine Learning Stability and Bandgaps of Lead‐Free Perovskites for Photovoltaics
Authors: Stanley Jared C. , Mayr Felix , Gagliardi Alessio
Published: November 2019

Compositional engineering of perovskites has enabled the precise control of material properties required for their envisioned applications in photovoltaics. However, challenges remain to address efficiency, stability, and toxicity simultaneously. Mixed lead‐free and inorganic perovskites have recently demonstrated potential for resolving such issues but their composition space is gigantic, making it difficult to discover promising candidates even using high‐throughput methods. A machine learning approach employing a generalized element‐agnostic fingerprint is shown to rapidly and accurately predict key properties using a new database of 344 perovskites generated with density functional theory. Bandgap, formation energy, and convex hull distance are predicted using validation subsets to within 146 meV, 15 meV per atom, and 11 meV per atom, respectively. The resulting model is used to predict trends in entirely different chemical spaces, and perform rapid composition and configuration space sampling without the need for expensive ab initio simulations.
Realizing Wafer‐Scale and Low‐Voltage Operation MoS2 Transistors via Electrolyte Gating
Authors: Tang Hongwei , Niu Wei , Liao Fuyou , Zhang Haima , Xu Hu , Deng Jianan , Chen Jing , Qiu Zhijun , Wan Jing , Pu Yong , Bao Wenzhong
Published: November 2019

Electrolyte gating, based on the electric double‐layer effect, has been widely used for 2D layered materials (2DLMs), since it is capable of inducing an ultrahigh charge‐carrier density while requiring only a low gate voltage. However, the wafer‐scale fabrication of high‐performance field effect transistors (FETs) based on electrolyte gating remains challenging, due to the lack of an appropriate electrolyte film coating technique. Wafer‐scale MoS2 FETs gated by high‐quality thin electrolyte film are demonstrated. The electrolyte film, formed by spin‐coating method, has a characteristic capacitance in the order of 10 µF cm−2 and shows a great compatible capability in the device fabrication process. Such electrolyte‐based top‐gated FETs arrays are successfully manufactured based on the wafer‐scale MoS2 film thereafter. The resulting MoS2 FETs operate at a low voltage (<1 V) with a current on/off ratio exceeding 104, as well as a small steep subthreshold swing (110 mV dec−1). Moreover, the realization of enhancement mode (E‐mode) MoS2 FET induced by electrolyte gating shows great potential for multistage logic circuits. A resistance‐loaded MoS2 inverter is also demonstrated with an operation frequency up to 500 Hz. The results provide the possibilities for realizing large‐scale electrolyte‐gated logic circuits based on 2DLMs.
Intrinsic Dipole Coupling in 2D van der Waals Ferroelectrics for Gate‐Controlled Switchable Rectifier
Authors: Dai Mingjin , Li Kai , Wang Fakun , Hu Yunxia , Zhang Jia , Zhai Tianyou , Yang Bin , Fu Yongqing , Cao Wenwu , Jia Dechang , Zhou Yu , Hu PingAn
Published: November 2019

Miniaturization of device elements, such as ferroelectric diodes, depends on the downscaling of ferroelectric film, which is also crucial for developing high‐density information storage technologies of ferroelectric random access memories (FeRAMs). Recently emerged ferroelectric two‐dimensional (2D) van der Waals (vdWs) layered materials bring an additional opportunity to further increase the density of FeRAMs. A lateral, switchable rectifier is designed and fabricated based on atomically thin 2D α‐In2Se3 ferroelectric diodes, thus breaking the thickness limitation of conventional ferroelectric films and achieving an unprecedented level of miniaturization. This is realized through the interrelated coupling between out‐of‐plane and in‐plane dipoles at room temperature; that is, horizontal polarization reversal can be effectively controlled through a vertical electric field. Being further explored as a switchable rectifier, the obtained maximum value of rectification ratio for the α‐In2Se3 based ferroelectric diode can reach up to 2.5 × 103. These results indicate that 2D ferroelectric semiconductors can offer a pathway to develop next‐generation multifunctional electronics.
Growth hormone deficiency in megalencephaly‐capillary malformation syndrome: An association with activating mutations in PIK3CA
Authors: Davis Shanlee , Ware Meredith A. , Zeiger Jordan , Deardorff Matthew A. , Grand Katheryn , Grimberg Adda , Hsu Stephanie , Kelsey Megan , Majidi Shideh , Matthew Revi P. , Napier Melanie , Nokoff Natalie , Prasad Chitra , Riggs Andrew C. , McKinnon Margaret L. , Mirzaa Ghayda
Published: November 2019

Megalencephaly‐capillary malformation syndrome (MCAP) is a brain overgrowth disorder characterized by cortical malformations (specifically polymicrogyria), vascular anomalies, and segmental overgrowth secondary to somatic activating mutations in the PI3K‐AKT–MTOR pathway (PIK3CA). Cases of growth failure and hypoglycemia have been reported in patients with MCAP, raising the suspicion for unappreciated growth hormone (GH) deficiency. Here we report an observational multicenter study of children with MCAP and GH deficiency. Eleven participants were confirmed to have GH deficiency, all with very low or undetectable circulating concentrations of insulin‐like growth factor‐1 and insulin‐like growth factor binding protein‐3. Seven underwent GH stimulation testing and all had insufficient responses with a median GH peak of 3.7 ng/ml (range 1.1–8.6). Growth patterns revealed a drastic decline in length z‐scores within the first year of life but then stabilized afterward. Five were treated with GH; one discontinued due to inconsolability. The other four participants continued on GH with improvement in linear growth velocity. Other endocrinopathies were identified in 7 of the 11 participants in this cohort. This study indicates that GH deficiency is associated with MCAP and that children with MCAP and hypoglycemia and/or postnatal growth failure should be evaluated for GH deficiency and other endocrinopathies.
Predictors of long‐term success and failure in primary and revision endoscopic dacryocystorhinostomy
Authors: Lehmann Ashton E. , Scangas George A. , Jafari Aria , Banks Catherine G. , Fullerton Zoe H. , Metson Ralph
Published: November 2019

Background

Although endoscopic dacryocystorhinostomy (endo‐DCR) is a common treatment of nasolacrimal duct obstruction, little is known about the determinants of surgical success and failure. The purpose of this study was to identify patient‐ and technique‐specific factors that may influence surgical outcomes of primary and revision endo‐DCR.

Methods

A retrospective review was conducted of 596 patients who underwent endo‐DCR over a 30‐year period (1989‐2018). Patients’ demographics and surgical techniques were assessed.

Results

Among the cohort of patients (n = 478) who underwent primary endo‐DCR, 10% (n = 48) required revision surgery. Patients who failed primary DCR tended to be younger (p = 0.015) and were less likely to have chronic sinonasal inflammation on histopathology (p = 0.047) than the successful surgery group. After adjusting for patient demographics and comorbidities, the occurrence of a postoperative complication was significantly associated with primary DCR failure (odds ratio [OR], 2.2; p = 0.032). Among the cohort of patients (n = 118) who underwent revision endo‐DCR, 8.5% (n = 10) required additional revision surgery. Patients who failed revision DCR tended to be younger (p = 0.022), more likely to have had intraoperative laser usage (p = 0.031), and more likely to have had an intraoperative complication (p = 0.013) than the successful revision surgery group. Endo‐DCR failure was not associated with smoking status, middle turbinate resection, or intraoperative visualization of the internal common punctum (p > 0.05).

Conclusion

An understanding of factors associated with primary and revision endo‐DCR failure can help to inform preoperative counseling, intraoperative surgical technique, and postoperative care in the treatment of patients with nasolacrimal duct obstruction.
Efficient Heterogeneous Palladium‐Catalyzed Oxidative Cascade Reactions of Enallenols to Furan and Oxaborole Derivatives
Authors: Li Man‐Bo , Posevins Daniels , Geoffroy Antoine , Zhu Can , Bäckvall Jan‐E.
Published: November 2019

A heterogeneous palladium‐catalyzed oxidative cyclization of enallenols has been developed for the construction of highly substituted furan and oxaborole derivatives. The heterogeneous catalyst (Pd‐AmP‐MCF) exhibits high activity, high site‐ and stereoselectivity, and efficient palladium recyclability in the transformations.
Dodecatwistarene Imides with Zigzag‐Twisted Conformation for Organic Electronics
Authors: Liu Guogang , Xiao Chengyi , Negri Fabrizia , Li Yan , Wang Zhaohui
Published: November 2019

1D nonplanar graphene nanoribbons generally have three possible conformers: helical, zigzag, and mixed conformations. Now, a kind of 1D nonplanar graphene nanoribbon, namely dodecatwistarene imides featuring twelve linearly fused benzene rings, was obtained by bottom‐up synthesis of palladium‐catalyzed Stille coupling and C−H activation. Single‐crystal X‐ray diffraction analyses revealed that it displays a zigzag‐twisted conformation caused by steric hindrance between imide groups and neighboring annulated benzene rings with the pendulum angle of 53°. This conformation is very stable and could not convert into other conformations even when heated up to 250 °C for 6 h. Despite of the highly twisted topology, organic field‐effect transistor based on it exhibits electron mobility up to 1.5 cm2 V−1 s−1 after annealing.
Stereospezifische und chemoselektive kupferkatalysierte, deaminierende Silylierung von Benzylammoniumtriflaten
Authors: Scharfbier Jonas , Gross Benjamin M. , Oestreich Martin
Published: November 2019

Es wird über eine Methode zur Synthese von Benzylsilanen ausgehend von den entsprechenden Ammoniumtriflaten berichtet. Dafür werden Silylboronsäureester als Siliciumpronukleophile eingesetzt, und die Reaktion wird von Kupfer(I)‐Salzen katalysiert. Enantiomerenangereicherte Benzylammoniumsalze reagieren stereospezifisch über eine SN2‐artige Verdrängung der Ammoniumgruppe, wodurch die α‐chiralen Silane mit Inversion der Konfiguration erzeugt werden. Ein cyclopropylsubstituiertes Substrat geht keine Ringöffnung ein, was einen ionischen Reaktionsmechanismus ohne Beteiligung einer radikalischen Zwischenstufe nahelegt.
Self‐Stabilized and Strongly Adhesive Supramolecular Polymer Protective Layer Enables Ultrahigh‐Rate and Large‐Capacity Lithium‐Metal Anode
Authors: Wang Gang , Chen Chao , Chen Yunhua , Kang Xiongwu , Yang Chenghao , Wang Fei , Liu Yong , Xiong Xunhui
Published: November 2019

Constructing a solid electrolyte interface (SEI) is a highly effective approach to overcome the poor reversibility of lithium (Li) metal anodes. Herein, an adhesive and self‐healable supramolecular copolymer, comprising of pendant poly(ethylene oxide) (PEO) segments and ureido‐pyrimidinone (UPy) quadruple‐hydrogen‐bonding moieties, is developed as a protection layer of Li anode by a simple drop‐coating. The protection performance of in‐situ‐formed LiPEO–UPy SEI layer is significantly enhanced owing to the strong binding and improved stability arising from a spontaneous reaction between UPy groups and Li metal. An ultrathin (approximately 70 nm) LiPEO–UPy layer can contribute to stable and dendrite‐free cycling at a high areal capacity of 10 mAh cm−2 at 5 mA cm−2 for 1000 h. This coating together with the promising electrochemical performance offers a new strategy for the development of dendrite‐free metal anodes.
A Light‐Triggerable Nanoparticle Library for the Controlled Release of Non‐Coding RNAs
Authors: Blersch Josephine , Francisco Vitor , Rebelo Catarina , Jiménez‐Balsa Adrian , Antunes Helena , Gonzato Carlo , Pinto Sandra , Simões Susana , Liedl Klaus , Haupt Karsten , Ferreira Lino
Published: November 2019

RNA‐based therapies offer a wide range of therapeutic interventions including the treatment of skin diseases; however, the strategies to efficiently deliver these biomolecules are still limited due to obstacles related to the cellular uptake and cytoplasmic delivery. Herein, we report the synthesis of a triggerable polymeric nanoparticle (NP) library composed of 160 formulations, presenting physico‐chemical diversity and differential responsiveness to light. Six formulations were more efficient (up to 500 %) than commercially available lipofectamine in gene‐knockdown activity. These formulations showed differential internalization by skin cells and the endosomal escape was rapid (minutes range). The NPs were effective in the release of siRNA and miRNA. Acute skin wounds treated with the top hit NP complexed with miRNA‐150‐5p healed faster than wounds treated with scrambled miRNA. Light‐activatable NPs offer a new strategy to topically deliver non‐coding RNAs.
Tandem Cross‐Coupling/Spirocyclization/Mannich‐Type Reactions of 3‐(2‐Isocyanoethyl)indoles with Diazo Compounds toward Polycyclic Spiroindolines
Authors: Chen Guo‐Shu , Chen Shu‐Jie , Luo Jian , Mao Xiang‐Yu , Chan Albert Sun‐Chi , Sun Raymond Wai‐Yin , Liu Yun‐Lin
Published: November 2019

Tandem reactions of Pd‐catalyzed cross‐coupling of 3‐(2‐isocyanoethyl)indoles with diazoacetates and subsequent spirocyclization/Mannich‐type reaction have been developed to assemble polycyclic spiroindoline skeletons. Formation of spiroindolenines has been proven as the crucial step for the following Mannich‐type cyclization reaction. Accordingly, a novel approach on chiral phosphoric acid catalyzed Mannich‐type cyclization toward the formation of diastereomerically and enantiomerically enriched pentacyclic spiroindolines has been established. Moreover, the products of the reaction are versatile building blocks in synthetic chemistry, as demonstrated by the synthesis of the key framework of aspidosperma and kopsia alkaloids.
Revealing the Nature of Singlet Fission under the Veil of Internal Conversion
Authors: Wang Long , Bai Shuming , Wu Yishi , Liu Yanping , Yao Jiannian , Fu Hongbing
Published: November 2019

Singlet fission (SF) holds the potential to boost the maximum power conversion efficiency of photovoltaic devices. Internal conversion (IC) has been considered as one of the major competitive deactivation pathways to transform excitation energy into heat. Now, using time‐resolved spectroscopy and theoretical calculation, it is demonstrated that, instead of a conventional IC pathway, an unexpected intramolecular singlet fission (iSF) process is responsible for excited state deactivation in isoindigo derivatives. The 1TT state could form at ultrafast rate and nearly quantitatively in solution. In solid films, the slipped stacked intermolecular packing of a thiophene‐functionalized derivative leads to efficient triplet pair separation, giving rise to an overall triplet yield of 181 %. This work not only enriches the pool of iSF‐capable materials, but also contributes to a better understanding of the iSF mechanism, which could be relevant for designing new SF sensitizers.
Real‐Time NMR Spectroscopy for Studying Metabolism
Authors: Alshamleh Islam , Krause Nina , Richter Christian , Kurrle Nina , Serve Hubert , Günther Ulrich L. , Schwalbe Harald
Published: November 2019

Current metabolomics approaches utilize cellular metabolite extracts, are destructive, and require high cell numbers. We introduce here an approach that enables the monitoring of cellular metabolism at lower cell numbers by observing the consumption/production of different metabolites over several kinetic data points of up to 48 hours. Our approach does not influence cellular viability, as we optimized the cellular matrix in comparison to other materials used in a variety of in‐cell NMR spectroscopy experiments. We are able to monitor real‐time metabolism of primary patient cells, which are extremely sensitive to external stress. Measurements are set up in an interleaved manner with short acquisition times (approximately 7 minutes per sample), which allows the monitoring of up to 15 patient samples simultaneously. Further, we implemented our approach for performing tracer‐based assays. Our approach will be important not only in the metabolomics fields, but also in individualized diagnostics.
On‐Surface Synthesis and Characterization of Triply Fused Porphyrin–Graphene Nanoribbon Hybrids
Authors: Mateo Luis M. , Sun Qiang , Liu Shi‐Xia , Bergkamp Jesse J. , Eimre Kristjan , Pignedoli Carlo A. , Ruffieux Pascal , Decurtins Silvio , Bottari Giovanni , Fasel Roman , Torres Tomas
Published: November 2019

On‐surface synthesis offers a versatile approach to prepare novel carbon‐based nanostructures that cannot be obtained by conventional solution chemistry. Graphene nanoribbons (GNRs) have potential for a variety of applications. A key issue for their application in molecular electronics is in the fine‐tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non‐benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) is a highly appealing strategy. Herein we present the selective on‐surface synthesis of a Por–GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the Por–GNR hybrid has been characterized by bond‐resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc‐AFM). The electronic properties have been investigated by scanning tunneling spectroscopy (STS), in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV.
Organotin (IV) Complexes as Catalyst for Biodiesel Formation: Synthesis, Structural Elucidation and Computational Studies
Authors: Zubair Muhammad , Sirajuddin Muhammad , Haider Ali , Hussain Ishtiaq , Tahir Muhammad Nawaz , Ali Saqib
Published: November 2019

Here we have presented the synthesis of three novel triorganotin (IV) complexes: trimethylstannyl 4‐(3‐chloro‐2‐methylphenylamino)‐4‐oxobut‐2‐enoate (1); tributylstannyl 4‐(3‐chloro‐2‐methylphenylamino)‐4‐oxobut‐2‐enoate (2) and triphenylstannyl 4‐(3‐chloro‐2‐methylphenylamino)‐4‐oxobut‐2‐enoate (3). The ligand and its three complexes were spectroscopically characterized by NMR (1H and 13C) in solution and by FT‐IR in solid state. Complexes 1 and 2 were further characterized by single crystal X‐ray diffraction analysis. The X‐ray crystallographic data reveal that complexes 1 and 2 both are structurally trialkytin(IV) analogs with distorted trigonal bipyramidal geometry. The geometry around tin atom is constituted by three alkyl groups (methyl in complex 1 and butyl in complex 2) occupying the equatorial positions and two oxygen atoms of 4‐(3‐chloro‐2‐methylphenylamino)‐4‐oxobut‐2‐enoic acid ligand occupying the axial positions. The computational study was performed applying LANL2DZ (Los Alamos National Laboratory 2 Double‐Zeta) functional with B3LYP (Lee, Yang and Parr) level of theory to obtain the optimized geometry, spectroscopic analysis, frontier molecular orbitals as well as global and local reactivity. A good correlation was found between the experimental and computational results. The homogeneous catalytic performance of synthesized compounds was evaluated for the transesterification of corn oil with methanol into biodiesel. The obtained corn oil biodiesel (COB) was confirmed by FT‐IR, 1H NMR and GC–MS. The catalytic results revealed that the complexes were active at optimized conditions and therefore can be potential candidates for the development of new catalytic system for biodiesel production.
Microlayer and nanolayer tubing and piping via layer multiplication coextrusion. I. Validation
Authors: Schneider Tyler , Danda Chaitanya , Ling Gerald , Colton Mark F. , McCauley Kevin M. , Maia João
Published: November 2019

Layered annular structures produced with layer multiplication coextrusion, utilizing both a standard in‐line “spider” die, and a custom annular die, are compared in structures up to 129 layers. One multilayered system, of a Dow LDPE 5004I was utilized in generating experimental results to validate the custom die design performance. It was found that the custom design demonstrates successful extrusion of high layer number annular structures with substantial benefits over the standard spider die. Moreover, a design method incorporating angular rotation was implemented within the custom die to eliminate weld lines and attain concentric layer structures to further enhance commercial viability and mechanical integrity. Results indicate angular rotation may be utilized to generate idealized annular products with concentric layer structures. Additionally, exploration of flow through the annular die land was conducted with ANSYS Polyflow in under several conditions of angular rotation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48683.
Mechanical and biodegradation properties of bamboo fiber‐reinforced starch/polypropylene biodegradable composites
Authors: Yang Feiwen , Long Haibo , Xie Baojun , Zhou Wuyi , Luo Ying , Zhang Chaoqun , Dong Xianming
Published: November 2019

Bamboo fiber (BF)‐reinforced starch/polypropylene (PP) composites were prepared by extrusion and injection molding methods. The mechanical and thermal properties and water absorption were evaluated by different methods. Moreover, composite samples were subjected to biodegradation through soil burial test and microbes medium degradation. Different stages of biodegradation were investigated by weight loss, attenuated total reflection Fourier transformed infrared spectroscopy, differential scanning calorimeter, and scanning electron microscope. It was found that contents of BF and starch resin had a significant influence on the properties of the composites. With more content of BF, the composite exhibited a better flexural property and biodegradation. A distinct decrease of weight loss and mechanical properties indicated the degradation caused by the microbes. After biodegradation, thermal stability of the composites decreased while the crystallinity of PP increased. The results prove that the composites more easily tend to be degraded and assimilated by microbes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48694.
Lessons learned from the developmental origins of childhood renal cancer
Authors: Chong Wai Chin , Cain Jason E.
Published: November 2019

Despite the rarity of renal tumors in children, many different types of malignant and nonmalignant renal neoplasms have been described. Therefore, the correct diagnosis and clinical management of these patients can represent a challenge. Here we provide a comprehensive review of the commonly diagnosed pediatric renal malignancies, including nephroblastoma (commonly known as Wilms tumor), clear cell sarcoma of the kidney, rhabdoid tumor of the kidney, several subtypes of renal cell tumors (often collectively termed renal cell carcinoma), and congenital mesoblastic nephroma. The epidemiology, pathology, treatments, underlying genetic and molecular mechanisms, and proposed developmental origins are discussed in detail, highlighting differential features and potential improved therapeutic strategies for affected individuals.