bluuebunny/crossref_metadata_2025_split huggingface dataset:
1‐Nitropropane [MAK Value Documentation, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: January 2019

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) for 1‐nitropropane, considering all toxicity endpoints. The critical effects of 1‐nitropropane [108‐03‐2] were inflammation and degeneration of the olfactory mucosa and inflammation of the squamous epithelium in rats after 28 or 47 days inhalation. The study yielded a NOAEC of 24 ml/m3for local effects. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. According to this approach, the MAK value for 1‐nitropropane has been lowered from 25 ml/m3to a concentration of 2 ml/m3. As local effects are critical, the assignment to Peak Limitation Category I is confirmed. The excursion factor of 8 is set as a human volunteer study revealed irritative effects only at considerably higher concentrations. Because there are no studies of teratogenicity, the substance is classified in Pregnancy Risk Group D. Skin contact is expected to contribute significantly to systemic toxicity and 1‐nitropropane is designated with an “H”. 1‐Nitropropane is not genotoxic and data for carcinogenicity are lacking. Sensitization is not expected from the limited data.
2‐Butoxyethanol (Ethylene glycol monobutyl ether) [MAK Value Documentation, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: January 2019

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the carcinogenicity classification of 2‐butoxyethanol [
111‐76‐2
]. In long‐term studies, 2‐butoxyethanol resulted in hepatocellular carcinomas, haemangiosarcomas and forestomach tumours in mice and phaeochromocytomas in rats and was classified in Carcinogen Category 4.

New studies indicate that the hepatic tumours and the phaeochromocytomas are consequences of the haemolysis which is caused by the metabolite butoxyacetic acid. The forestomach tumours in mice are judged to be irrelevant for humans. There are differences between rats and humans concerning the formation and the haemolytic potency of butoxyacetic acid, which renders humans much less susceptible for haemolysis than rats, although humans can develop signs of haemolysis after severe oral intoxication. However, the CNS‐depression and the irritation caused by 2‐butoxyethanol precludes that humans are exposed regularly to 2‐butoxyethanol concentrations at the workplace which might result in significant haemolysis. Therefore, the Commission has removed 2‐butoxyethanol from the Carcinogen Category 4.
trans‐1,3,3,3‐Tetrafluorpropen [MAK Value Documentation in German language, 2019]
Authors: Hartwig A. ,   MAK Commission
Published: January 2019

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of trans‐1,3,3,3‐tetrafluoropropene [
29118‐24‐9
]. As the blood:air partition coefficient of trans‐1,3,3,3‐tetrafluoropropene is < 5, the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c) does not have to be taken into account for the derivation of the MAK value. Even after extrapolation of 6‐hour exposure in the animal experiment to 8‐hour exposure at the workplace, the MAK value for trans‐1,3,3,3‐tetrafluoropropene of 1000 ml/m
3
can be retained.
Longitudinal trajectories of perpetration of adolescent dating abuse in a national sample
Authors: Mumford Elizabeth A. , Liu Weiwei , Taylor Bruce G. 
Published: January 2019

AbstractDespite extensive research regarding patterns and outcomes of victimization in dating relationships, there has been limited investigation of the developmental profiles of the perpetration of adolescent dating abuse (ADA). We estimated longitudinal latent growth models of ADA perpetration in a sample of 2,269 U.S. adolescents/young adults ages 12–18 at baseline, drawing on four waves (2013–2017) of data from the nationally representative Survey of Teen Relationships and Intimate Violence. Model results revealed three classes representing “nondaters,” respondents showing “increasing dating/ADA,” and respondents with “high/stable dating/ADA.” Results support prior research finding heightened patterns of ADA perpetration by older youth, and distinguish individual and family characteristics associated with adolescent/young adults’ ADA perpetration for the purpose of informing individual and programmatic prevention efforts.
van der Waals Epitaxial Growth of Atomically Thin 2D Metals on Dangling‐Bond‐Free WSe2 and WS2
Authors: Wu Ruixia , Tao Quanyang , Dang Weiqi , Liu Yuan , Li Bo , Li Jia , Zhao Bei , Zhang Zhengwei , Ma Huifang , Sun Guangzhuang , Duan Xidong , Duan Xiangfeng 
Published: January 2019

Abstract2D metals have attracted considerable recent attention for their special physical properties, such as charge density waves, magnetism, and superconductivity. However, despite some recent efforts, the synthesis of ultrathin 2D metals nanosheets down to monolayer thickness remains a significant challenge. Herein, by using atomically flat 2D WSe2 or WS2 as the growth substrate, the synthesis of atomically thin 2D metallic MTe2 (M = V, Nb, Ta) single crystals with the thickness down to the monolayer regime and the creation of atomically thin MTe2/WSe2 (WS2) vertical heterojunctions is reported. Comparison with the growth on the SiO2/Si substrate under the same conditions reveals that the utilization of the dangling‐bond‐free WSe2 or WS2 as the van der Waals epitaxy substrates is crucial for the successful realization of atomically thin MTe2 (M = V, Nb, Ta) nanosheets. It is further shown that the epitaxial grown 2D metals can function as van der Waals contacts for 2D semiconductors with little interface damage and improved electronic performance. This study defines a robust van der Waals epitaxy pathway to ultrathin 2D metals, which is essential for fundamental studies and potential technological applications of this new class of materials at the 2D limit.
Degradable Nanoparticles Restore Lysosomal pH and Autophagic Flux in Lipotoxic Pancreatic Beta Cells
Authors: Zeng Jialiu , Shirihai Orian S. , Grinstaff Mark W. 
Published: January 2019

AbstractChronic exposure to high levels of fatty acids (lipotoxicity) in pancreatic beta cells (β‐cells) decreases lysosomal acidity and inhibits autophagic flux. Today, there are a lack of approaches to modify lysosomal acidity to determine whether impaired lysosomal acidification is causally inhibiting autophagic flux and cellular functions. Biodegradable poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles (NPs) with diameters of ≈100 nm localize to lysosomes and serve as an ideal method to deliver lactic and glycolic acid to lysosomes upon NP polymer degradation. In this study, the ability of PLGA NPs to lower lysosomal pH and restore autophagic flux is investigated in pancreatic insulin secreting (INS1) β‐cells. PLGA NPs display a concentration dependent performance with higher concentrations of PLGA NPs, lowering lysosomal pH, as well as restoring autophagic flux and insulin secretion in pancreatic β‐cells. These results document that acidifying the lysosome, via an external perturbation, in lipotoxic pancreatic β‐cells affords a specific biological outcome of improved cellular degradative activity.
Biological and Engineered Topological Droplet Rectifiers
Authors: Li Jing , Li Jiaqian , Sun Jing , Feng Shile , Wang Zuankai 
Published: January 2019

AbstractThe power of the directional and spontaneous transport of liquid droplets is revealed through ubiquitous biological processes and numerous practical applications, where droplets are rectified to achieve preferential functions. Despite extensive progress, the fundamental understanding and the ability to exploit new strategies to rectify droplet transport remain elusive. Here, the latest progress in the fundamental understanding as well as the development of engineered droplet rectifiers that impart superior performance in a wide variety of working conditions, ranging from low temperature, ambient temperature, to high temperature, is discussed. For the first time, a phase diagram is formulated that naturally connects the droplet dynamics, including droplet formation modes, length scales, and phase states, with environmental conditions. Parallel approaches are then taken to discuss the basic physical mechanisms underlying biological droplet rectifiers, and a variety of strategies and manufacturing routes for the development of robust artificial droplet rectifiers. Finally, perspectives on how to create novel man‐made rectifiers with functionalities beyond natural counterparts are presented.
Templated Synthesis of Ultrafine Polyaniline Fibers and Their Transfer to Carbon Substrates for Highly Rapid Redox Reactions
Authors: Itoi Hiroyuki , Shimomura Kento , Hasegawa Hideyuki , Nomura Naoya , Ohta Yuina , Iwata Hiroyuki , Hoshikawa Yasuto , Ohzawa Yoshimi 
Published: January 2019

AbstractPolyaniline ultrafine fibers (PANI‐UFs) prepared using commercial activated carbon (AC) as a template are transferred to conductive carbon substrates. This method starts with the adsorption of aniline in AC, followed by its subsequent electrochemical polymerization to produce PANI‐UFs inside the AC pores. The resulting PANI‐UFs can be transferred onto carbon substrates under an applied potential. In this study, two kinds of AC with different pore sizes (≈2 and ≈4 nm) are used, and carbon black, graphite rods, highly oriented pyrolytic graphite, and stainless steel are examined as conductive substrates. It is found that the transfer of PANI‐UFs fails only in the case of stainless steel. The transfer of PANI‐UFs cannot be confirmed by transmission electron microscopy observation because of their ultrafine structures. However, their existence is confirmed by energy dispersive X‐ray spectroscopy, atomic force microscopy, and electrochemical analyses. The electrochemical analyses reveal that the electrochemical behavior of the PANI‐UFs is not affected by the pore size of the AC template. In addition, the PANI‐UFs are characterized by extremely rapid redox responses. This template method can be applied for the fabrication of PANI‐UFs on versatile conductive carbon substrates for use in highly sensitive sensors and other electronic devices.
Multiple Reaction Paths for CO Oxidation on a 2D SnOx Nano‐Oxide on the Pt(110) Surface: Intrinsic Reactivity and Spillover
Authors: Zheng Jian , Busch Michael , Artiglia Luca , Skála Tomáš , Rossmeisl Jan , Agnoli Stefano 
Published: January 2019

AbstractAn interface stabilized SnOx/Pt(110) nano‐oxide characterized by a c(2 × 4) surface reconstruction is prepared and characterized by low‐energy electron diffraction (LEED), synchrotron radiation photoemission spectroscopy (SRPES), and scanning tunneling microscopy (STM). Based on the experimental data, atomic models for the nano‐oxide are proposed and then validated by comparing the experimental results with the outcome of first‐principle calculations. The reactivity of the nano‐oxide toward CO is investigated, obtaining that the c(2 × 4) reconstruction efficiently oxidizes CO to CO2. The SnOx nano‐oxide on the Pt(110) surface can act as a reservoir for oxygen that can diffuse on the adjacent Pt areas where it oxidizes CO. This spillover effect endows the SnOx/Pt(110) system with enhanced tolerance to CO poisoning.
A Light‐Driven Micromotor with Complex Motion Behaviors for Controlled Release
Authors: Sun Yunyu , Liu Ye , Song Bo , Zhang Hui , Duan Ruomeng , Zhang Dafeng , Dong Bin 
Published: January 2019

AbstractMicromotor that exhibits various movement behaviors has attracted more attention in recent years. However, most researchers focus on its motion behavior and few have studied the fluid flow surrounding it. In this work, a novel micromotor with both controlled motion behavior and surrounding fluid flow, which is driven by near‐infrared (NIR) light based on the unique Marangoni effect caused by the light irradiation of its constituent, i.e., polypyrrole (PPy), is reported. Interestingly, these motion behaviors and the surrounding fluid flow can be easily switched by adjusting the incident angle of the NIR laser. This unique property may have potentials in different fields. Among others, its application in remotely controlled targeted delivery and release is demonstrated.
High Throughput Nanoliposome Formation Using 3D Printed Microfluidic Flow Focusing Chips
Authors: Chen Zhu , Han Jung Yeon , Shumate Laura , Fedak Renee , DeVoe Don L. 
Published: January 2019

AbstractThe use of additive manufacturing to fabricate microfluidic devices capable of high throughout synthesis of nanoscale liposomes with tunable dimensions is demonstrated. Employing a high‐resolution 3D printing process based on stereolithography and digital light projection, microchannel geometries and printing parameters are optimized to enable reliable patterning of channel features with critical dimensions of 200 µm, supporting the production of lipid vesicles below 100 nm in diameter by microfluidic flow focusing. The additive manufacturing approach enables the fabrication of flow focusing microchannels with high aspect ratios, together with seamless fabrication of high‐pressure fluidic ports for world‐to‐chip interfacing, supporting large volumetric flow rates and high‐throughput nanoparticle synthesis, with demonstrated production rates for optimized liposomes as high as 4 mg min−1 from a single device.
Local Chemistry Engineering in Doped Photonic Glass for Optical Pulse Generation
Authors: Chen Jiejie , Shi Zhuo , Zhou Shifeng , Fang Zaijin , Lv Shichao , Yu Haohai , Hao Jianhua , Zhang Huaijin , Wang Jiyang , Qiu Jianrong 
Published: January 2019

AbstractThe control of the optical response of multicomponent photonic glass through short‐ to medium‐range chemistry design has led to the development of high‐performance devices with efficient stimulated radiation, broadband optical amplification, and sensitive optical sensing. However, the success of optical modulation with an all‐fiber configuration is limited by the difficulty in creating smart structural units that can dynamically switch light–matter interactions. Here, a local chemistry design strategy is reported that can help realize dynamic energy storage and its controllable release, based on the simultaneous management of the chemical state and ligand field of transition‐metal dopant through glass crystallization. The theoretical analysis indicates that a four‐level configuration, such as that of tetrahedral Cr4+, can enable efficient photon–electron–photon conversion. Experimental data further reveal that this configuration can be stable in nanostructured glass. A nanostructured fiber with perfect core‐clad configuration is successfully fabricated by the melt‐in‐tube approach. The optical modulation function in bulk glass with estimated σgs and σes values of (1.39 ± 0.03) × 10−16 and (1.20 ± 0.02) × 10−16 cm2, respectively, is also demonstrated. Therefore, a principle pulse laser device with operation wavelength at 1.06 µm and pulse duration of 176 ns is fabricated for the first time.
Preparation and characterization of carbon fiber/polypropylene composites via a tri‐screw in‐line compounding and injection molding
Authors: Xiaochun Yin , Youhua Yin , Yanhong Feng , Guizhen Zhang , Jinsong Wen 
Published: January 2019

AbstractIn this study, a novel process called tri‐screw in‐line compounding and injection molding (TSICM) and corresponding apparatus had been developed for carbon fiber (CF) reinforced polypropylene (PP) composites. The structure and working principle were introduced in detail. Effects of carbon fiber loadings and screw rotation rates on mechanical, thermal, and morphological properties of CF/PP composites were experimentally investigated. Fiber length distributions of the composites were determined by using a vision measuring machine. It was found that the maximum number of fibers observed was in the range of 0–50 μm and the maximum length of the fiber in the composites is about 1 mm. Differential scanning calorimetry results showed that the melting enthalpy crystallinity of the composites decreased slightly with the increase in CF loading. Thermogravimetric analysis results showed that the thermal stability of the composites improved with increasing CF loading. Mechanical test results showed that the tensile, flexural strength, modulus, and impact strength increased with increasing CF loadings. The strain at break decreased with the increase in CF content. The increasing screw rotation rate decreased not only the tensile strength and modulus but also the flexural strength and modulus. However, it increased the strain at break values of composites.
Electrochemical Fluoroalkynylation of Aryl Alkenes with Fluoride Ions and Alkynyltrifluoroborate Salts
Authors: Xiong Peng , Long Hao , Xu Hai‐Chao 
Published: January 2019

AbstractAn electrochemical fluoroalkynylation reaction of aryl alkenes has been developed using fluoride ions and alkynyltrifluoroborate salts as the source of functional groups. The electric‐powered vicinal alkene difunctionalization reactions add a fluorine and an alkynyl group across the alkene regioselectively without the need for transition‐metal catalysts and oxidizing reagents.
Site‐Specific Oxidation State Assignments of the Iron Atoms in the [4Fe:4S]2+/1+/0 States of the Nitrogenase Fe‐Protein
Authors: Wenke Belinda B. , Spatzal Thomas , Rees Douglas C. 
Published: January 2019

AbstractThe nitrogenase iron protein (Fe‐protein) contains an unusual [4Fe:4S] iron‐sulphur cluster that is stable in three oxidation states: 2+, 1+, and 0. Here, we use spatially resolved anomalous dispersion (SpReAD) refinement to determine oxidation assignments for the individual irons for each state. Additionally, we report the 1.13‐Å resolution structure for the ADP bound Fe‐protein, the highest resolution Fe‐protein structure presently determined. In the dithionite‐reduced [4Fe:4S]1+ state, our analysis identifies a solvent exposed, delocalized Fe2.5+ pair and a buried Fe2+ pair. We propose that ATP binding by the Fe‐protein promotes an internal redox rearrangement such that the solvent‐exposed Fe pair becomes reduced, thereby facilitating electron transfer to the nitrogenase molybdenum iron‐protein. In the [4Fe:4S]0 and [4Fe:4S]2+ states, the SpReAD analysis supports oxidation states assignments for all irons in these clusters of Fe2+ and valence delocalized Fe2.5+, respectively.
One‐Step Synthesis of Dendritic Highly Branched Polystyrenes by Organotellurium‐Mediated Copolymerization of Styrene and a Dienyl Telluride Monomer
Authors: Lu Yangtian , Yamago Shigeru 
Published: January 2019

AbstractDendritic highly branched polystyrenes (HB‐PSts) were prepared by a one‐step copolymerization of dienyl telluride 6 and St in the presence of organotellurium chain transfer agent 2. The molecular weight (MW), dendritic generation, and branching density were easily controlled by the ratio of 2 to 6 to styrene (St) with maintaining monodispersity. The branching efficiency estimated by a deuterium‐labeling experiment showed that 6 quantitatively (>95 %) served as the branching point. The end group fidelity was high (ca. 90 %) as determined by the end group transformation to pyrene‐derivative. Intrinsic viscosity of the HP‐polystyrenes was significantly lower than that of linear polystyrenes and were easily tuned by the branching number and branching density. The method is compatible of various functional groups and chloro and acetoxy‐substituted styrenes were also used as a comonomer. A tadpole block copolymer was also synthesized starting from linear PSt as a macroinitiator.
Porosity Switching in Polymorphic Porous Organic Cages with Exceptional Chemical Stability
Authors: Bera Saibal , Dey Kaushik , Pal Tapan K. , Halder Arjun , Tothadi Srinu , Karak Suvendu , Addicoat Matthew , Banerjee Rahul 
Published: January 2019

AbstractPorous solids that can be switched between different forms with distinct physical properties are appealing candidates for separation, catalysis, and host–guest chemistry. In this regard, porous organic cages (POCs) are of profound interest because of their solution‐state accessibility. However, the application of POCs is limited by poor chemical stability. Synthesis of an exceptionally stable imine‐linked (4+6) porous organic cage (TpOMe‐CDA) is reported using 2,4,6‐trimethoxy‐1,3,5‐triformyl benzene (TpOMe) as a precursor aldehyde. Introduction of the ‐OMe functional group to the aldehyde creates significant steric and hydrophobic characteristics in the environment around the imine bonds that protects the cage molecules from hydrolysis in the presence of acids or bases. The electronic effect of the ‐OMe group also plays an important role in enhancing the stability of the reported POCs. As a consequence, TpOMe‐CDA reveals exceptional chemical stability in neutral, acidic and basic conditions, even in 12 m NaOH. Interestingly, TpOMe‐CDA exists in three different porous and non‐porous polymorphic forms (α, β, and γ) with respect to differences in crystallographic packing and the orientation of the flexible methoxy groups. All of the polymorphs retain their crystallinity even after treatment with acids and bases. All the polymorphs of TpOMe‐CDA differ significantly in their properties as well as morphology and could be reversibly switched in the presence of an external stimulus.
Effect of modified rubber powder on the morphology and thermal and mechanical properties of blown poly(lactic acid)–hydroxyl epoxidized natural rubber films for flexible film packaging
Authors: Phetphaisit Chor Wayakron , Wapanyakul Wittawat , Phinyocheep Pranee 
Published: January 2019

ABSTRACTIn this study, we prepared and used modified natural rubber powder to increase the toughness of poly(lactic acid) (PLA) films. We blended PLA and hydroxyl epoxidized natural rubber (HENR) via a melt‐mixing process with twin‐screw extruder and a blowing machine. We investigated the influence of the HENR content in the blend films on the microstructure, thermal, mechanical, and optical properties. The morphology of the blend showed a coarse surface and elongated fibrils of HENR in the PLA matrix. After blowing, the dispersion of small particles of HENR in the substrate was seen. The size of the remaining HENR particles was smaller than that of the starting powder. The compatibility of HENR and the remaining rubber particles may have synergistically contributed to improvements in the elongation at break, impact strength, and ultraviolet–visible transition protection of the PLA films. The elongation at break drastically increased from 3 to 228% after PLA was blended with 20 wt % HENR. On the other hand, all of the blends exhibited lower glass‐transition temperatures and cold crystallization temperatures than the pure PLA films. We concluded that the blend was partially compatible and may have increased the flexibility of the PLA films. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47503.