bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of graphene nanoscrolls on the crystallization behavior and nano‐mechanical properties of polylactic acid
Authors: Ajala Oluwakemi , Werther Caroline , Nikaeen Peyman , Singh Raj Pal , Depan Dilip
Published: April 2019

Graphene nanoscrolls (GNS), one‐dimensional carbon‐based nanomaterials, have been predicted to possess extraordinary characteristics due to their unique open topology with scrolled graphene monolayers. In this study, the conversion of planar 2‐D graphene nanoplatelets (GNPs) to tubular and scrolled 1‐D GNSs is described. The effects of GNS as a nucleating agent to modulate the morphology, crystallization, and nano‐mechanical properties of polylactic acid (PLA) were studied. The nucleating effect of GNS and its unique topological characteristics proves to influence the crystallization of PLA. Fourier transform infrared (FTIR) spectroscopy indicated nonpreferential interactions of PLA chains around GNS due to the bulky and helical PLA macromolecular chains. Superior interfacial interactions and strain in GNS provide better load transfer between GNS and PLA matrices, resulting in higher modulus and hardness. This study is the first detailed analysis to elucidate the role of unique GNS to favorably modulate the properties of a polymer.
Development and characterization of fully bio‐based polybenzoxazine‐silica hybrid composites for low‐k and flame‐retardant applications
Authors: Krishnamoorthy Krishnadevi , Subramani Devaraju , Eeda Naveena , Muthukaruppan Alagar
Published: April 2019

In the present work, new classes of bio‐based polybenzoxazines were synthesized using eugenol as phenol source and furfurylamine and stearylamine as amine sources separately through solventless green synthetic process routes and were further reinforced with varying percentages (1, 3, 5, and 10 wt%) of silica (from rice husk) to attain hybrid composites. The molecular structure, cure behaviour, thermal stability, dielectric properties, and flame‐retardant behaviour of both benzoxazine monomers and benzoxazine composites were characterized using appropriate modern analytical techniques. The eugenol‐based benzoxazines synthesized using furfurylamine (FBz) and stearylamine (SBz) were cured at 223°C and 233°C, respectively. The differential scanning calorimetry (DSC) data reveal the glass transition temperatures (Tg) of FBz and SBz were 157°C and 132°C, respectively, and the maximum decomposition temperature (Tmax) as obtained from thermogravimetric analysis (TGA), were found to be 464°C and 398°C for FBz and SBz, respectively. The dielectric constants for FBz and SBz obtained at 1 MHz were 3.28 and 3.62, respectively. Furthermore, varying weight percentages (1, 3, 5, and 10 wt%) of 3‐mercaptopropyltrimethoxysilane (3‐MPTMS) functionalized bio‐silica reinforced the composite materials as evidenced by their improved thermal stability and lower dielectric constant. Data obtained from thermal and dielectric studies suggested that these polybenzoxazines could be used in the form of adhesives, sealants, and composites for high performance inter‐layer low‐k dielectric applications in microelectronics.
Characterization of pediatric hepatocellular carcinoma reveals genomic heterogeneity and diverse signaling pathway activation
Authors: Haines Katherine , Sarabia Stephen F. , Alvarez Karla R. , Tomlinson Gail , Vasudevan Sanjeev A. , Heczey Andras A. , Roy Angshumoy , Finegold Milton J. , Parsons D. Williams , Plon Sharon E. , López‐Terrada Dolores
Published: April 2019

Background

Pediatric hepatocellular carcinoma (HCC) is a rare liver tumor in children with a poor prognosis. Comprehensive molecular profiling to understand the underlying genomic drivers of this tumor has not been completed, and it is unclear whether nonfibrolamellar pediatric HCC is more genomically similar to hepatoblastoma or adult HCC.

Procedure

To characterize the molecular landscape of these tumors, we analyzed a cohort of 15 pediatric non‐FL‐HCCs by sequencing a panel of cancer‐associated genes and conducting copy‐number and gene‐expression analyses.

Results

We detected multiple types of molecular alterations in Wnt signaling genes, including APC inversion, AMER1 somatic mutation, and most commonly CTNNB1 intragenic deletions. There were multiple alterations to the telomerase pathway via TERT activation or ATRX mutation. Therapeutically targetable activating mutations in MAPK/ERK signaling pathway genes, including MAPK1 and BRAF, were detected in 20% of tumors. TP53 mutations occurred far less frequently in our pediatric HCC cohort than reported in adult cohorts. Tumors arising in children with underlying liver disease were found to be molecularly distinct from the remainder and lacking detectable oncogenic drivers, as compared with those arising in patients without a history of underlying liver disease; the majority of both types were positive for glypican‐3, another potential therapeutic target.

Conclusion

Our study revealed pediatric HCC to be a molecularly heterogeneous group of tumors. Those non‐FL‐HCC tumors arising in the absence of underlying liver disease harbor genetic alterations affecting multiple cancer pathways, most notably Wnt signaling, and share some characteristics with adult HCC.
Identification, Quantification, and System Analysis of Protein N‐ε Lysine Methylation in Anucleate Blood Platelets
Authors: Rocheleau Anne D. , Melrose Alexander R. , Cunliffe Jennifer M. , Klimek John , Babur Özgün , Tassi Yunga Samuel , Ngo Anh T. P. , Pang Jiaqing , David Larry L. , McCarty Owen J. T. , Aslan Joseph E.
Published: April 2019

Protein posttranslational modifications critically regulate a range of physiological and disease processes. In addition to tyrosine, serine, and threonine phosphorylation, reversible N‐ε acylation and alkylation of protein lysine residues also modulate diverse aspects of cellular function. Studies of lysine acyl and alkyl modifications have focused on nuclear proteins in epigenetic regulation; however, lysine modifications are also prevalent on cytosolic proteins to serve increasingly apparent, although less understood roles in cell regulation. Here, the methyl‐lysine (meK) proteome of anucleate blood platelets is characterized. With high‐resolution, multiplex MS methods, 190 mono‐, di‐, and tri‐meK modifications are identified on 150 different platelet proteins—including 28 meK modifications quantified by tandem mass tag (TMT) labeling. In addition to identifying meK modifications on calmodulin (CaM), GRP78 (HSPA5, BiP), and EF1A1 that have been previously characterized in other cell types, more novel modifications are also uncovered on cofilin, drebin‐like protein (DBNL, Hip‐55), DOCK8, TRIM25, and numerous other cytoplasmic proteins. Together, the results and analyses support roles for lysine methylation in mediating cytoskeletal, translational, secretory, and other cellular processes. MS data for this study have been deposited into the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD012217.
Star‐shaped siloxane polymers with various cyclic cores: Synthesis and properties
Authors: Vysochinskaya Yulia S. , Anisimov Anton A. , Peregudov Alexander S. , Dubovik Alexander S. , Orlov Vladimir N. , Malakhova Yulia N. , Stupnikov Alexey A. , Buzin Mikhail I. , Nikiforova Galina G. , Vasil'ev Victor G. , Shchegolikhina Olga I. , Muzafarov Aziz M.
Published: April 2019

Six new star‐shaped polydimethylsiloxane (PDMS) with various cyclic siloxane cores were synthesized by the “grafting onto” method. The polymers obtained feature low dispersity and well‐defined structures. Two of them, Q
8‐PDMS and D
12‐PDMS, have a three‐dimensional spatial structure traditional for star‐shaped polymers where the arms are arranged in all directions from the branching center. The other four polymers, D
4‐PDMS–D
8‐PDMS, have quite a different spatial geometry (cis‐structure) where all the PDMS‐arms are arranged on one side of the branching center plane. Such star‐shaped structures were not reported before. The structures and purity of the polymers obtained were confirmed using a set of physicochemical methods of analysis. The effect of the macromolecule structure on the properties of the target polymers was identified. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019
Characterization of the deposition behavior and changes in bonding structures of hexamethyldisiloxane and decamethylcyclopentasiloxane atmospheric plasma‐deposited films*
Authors: Gilliam Mary A. , Farhat Susan A. , Garner Graham E. , Stubbs Barrack P. , Peterson Benjamin B.
Published: April 2019

The plasma deposition behavior of hexamethyldisiloxane (HMDSO) and decamethylcyclopentasiloxane (D5) is investigated for an atmospheric pressure plasma jet. The energy‐deficient and monomer‐deficient domains are revealed by normalized parameters and no significant difference between HMDSO and D5 is observed. The results are supported by Fourier‐transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy. The data is also evaluated using an Arrhenius‐type equation and an empirical equation reported in the literature, but the correlation is not as good as the normalized parameters. Changes in Si–O–Si bonding arrangements are analyzed by deconvolution of the FTIR absorbance band, showing an increase in porous cage structures with higher normalized energy input.
Metal–Organic Framework Supported Palladium Nanoparticles: Applications and Mechanisms
Authors: Yang Qi , Yao Fubing , Zhong Yu , Chen Fei , Shu Xiaoyu , Sun Jian , He Li , Wu Bo , Hou Kunjie , Wang Dongbo , Li Xiaoming
Published: April 2019

Heterogeneous palladium (Pd)‐based catalysts are extensively applied to improve the catalytic performance and/or expand the reaction scope in many catalytic processes, involving the cross‐coupling, hydrogenation, reduction, and oxidation reactions. Among them, metal–organic framework (MOF)‐supported Pd nanoparticles (Pd NPs) are becoming the most popular one for their excellent catalytic performance and reusable property. To motivate the development of this technology, the applications of MOF‐supported Pd NPs (Pd NPs/MOFs) in heterogeneous catalysis are critically summarized herein, including the hydrogenation reduction of nitro‐ and polyunsaturated compounds, synthesis of carbon–carbon (CC) bonds compounds, chromium (Cr(VI)) reduction, dehalogenation, alcohol oxidation, CO2 conversion, and CO oxidation. The influences of base, solvents, electron character of substitutes, and type of halogen on the catalytic performance are comprehensively discussed. Finally, the application prospects of Pd NPs/MOFs and existing shortcomings in the catalytic field are proposed.
Equilibrium, affinity, dissociation constants, IC5O: Facts and fantasies
Authors: Barbet Jacques , Huclier‐Markai Sandrine
Published: April 2019

The interaction between ligands and receptors is often described in terms of 50% inhibitory concentrations (IC50). However, IC50 values do not accurately reflect the dissociation constants (Kd), and the domain of application and precision of proposed approximations for Kd estimation are unclear. The effect of affinity and of experimental conditions on the differences between IC50 and Kd has been assessed from exact mass action law calculations and from computer simulations. Competitions between [111In]DTPA‐indium and a few metal‐DTPA complexes for binding to a specific antibody are discussed as a practical example. Exact calculations of competition assays have been implemented in Microsoft Excel and performed for a variety of concentrations of receptor, tracer, and competitor. The results are identical to those of software packages. IC50 is found larger than Kd by less than 20% only when tracer concentration is small compared with Kd and to the receptor concentration and when this receptor concentration is small compared with Kd. Otherwise, Kd and IC50 may be very different and approximations proposed in the literature to obtain Kd values from graphically derived IC50 are not acceptable as soon as the concentrations of tracer or of receptor approach Kd. Under most experimental conditions, IC50 values do not reflect Kd values. Using available software packages to determine and report Kd values would allow for more meaningful comparisons of results obtained under different experimental conditions.
Spatio‐temporal variability in underwater light climate in a turbid river‐floodplain system: Driving factors and estimation using Secchi disc
Authors: Mayora Gisela , Devercelli Melina
Published: April 2019

The underwater light climate has important effects on primary producers. The aim of this research was to evaluate its variability in a turbid river‐floodplain system. Photosynthetically active radiation (PAR) was measured in the Middle Paraná River during different hydrological phases to (a) analyse the photosynthetically active radiation attenuation coefficient (k) and euphotic depth (Zeu) as well as their associations with optically active components and (b) develop and evaluate indices and regression models based on Secchi disc (SD) measurements to estimate k and Zeu. Values of k were higher in the fluvial system than in the floodplain and during low‐water stage than high‐water stage. Particulate components controlled the light climate variability. Chromophoric dissolved organic matter and chlorophyll‐a had significant effects during floods. The estimation of k and Zeu was sensitive to temporal but not to spatial variations. The highest prediction accuracy was observed when using specific non‐linear regressions for each hydrological phase, especially for Zeu estimation (low stage: k = 1.76 × SD−0.80, Zeu = 2.62 × 1/SD−0.80; high stage: k = 2.04 × SD−0.53, Zeu = 2.26 × 1/SD−0.53). The indices k × SD and Zeu/SD were significantly different from those proposed for clear water environments. It is concluded that temporal variations should be considered when estimating k and Zeu in turbid river‐floodplain systems because of the temporal heterogeneity in optically active components. Considering that ecological implication of the light climate depends on Zeu:depth ratio, we propose to estimate Zeu instead of k. Finally, indices proposed for clear water environments are not recommended to be applied to turbid environments.
Generation of a Functioning and Self-Renewing Diaphragmatic Muscle Construct
Authors: Trevisan Caterina , Fallas Mario Enrique Alvrez , Maghin Edoardo , Franzin Chiara , Pavan Piero , Caccin Paola , Chiavegato Angela , Carraro Eugenia , Boso Daniele , Boldrin Francesco , Caicci Federico , Bertin Enrica , Urbani Luca , Milan Anna , Biz Carlo , Lazzari Lorenza , De Coppi Paolo , Pozzobon Michela , Piccoli Martina
Published: April 2019

Surgical repair of large muscular defects requires the use of autologous graft transfer or prosthetic material. Naturally derived matrices are biocompatible materials obtained by tissue decellularization and are commonly used in clinical practice. Despite promising applications described in the literature, the use of acellular matrices to repair large defects has been only partially successful, highlighting the need for more efficient constructs. Scaffold recellularization by means of tissue engineering may improve not only the structure of the matrix, but also its ability to functionally interact with the host. The development of such a complex construct is challenging, due to the complexity of the native organ architecture and the difficulties in recreating the cellular niche with both proliferative and differentiating potential during growth or after damage. In this study, we tested a mouse decellularized diaphragmatic extracellular matrix (ECM) previously described by our group, for the generation of a cellular skeletal muscle construct with functional features. The decellularized matrix was stored using different conditions to mimic the off-the-shelf clinical need. Pediatric human muscle precursors were seeded into the decellularized scaffold, demonstrating proliferation and differentiation capability, giving rise to a functioning three-dimensional skeletal muscle structure. Furthermore, we exposed the engineered construct to cardiotoxin injury and demonstrated its ability to activate a regenerative response in vitro promoting cell self-renewal and a positive ECM remodeling. Functional reconstruction of an engineered skeletal muscle with maintenance of a stem cell pool makes this a promising tool toward future clinical applications in diaphragmatic regeneration. Stem Cells Translational Medicine  2019;8:858–869
Economic growth and human development: Evidence from Zambia
Authors: Chikalipah Sydney , Makina Daniel
Published: April 2019

In this paper, we examine the two‐way relationship between economic growth and human development in Zambia over the period 1970 to 2015. By applying the cointegration and vector error correction model techniques, our estimates demonstrate, in the first instance, that economic growth and human development are cointegrated. Second, there is no evidence of two‐way causal effect observable between economic growth and human development in the short run. In marked contrast, we find that economic growth has long‐run effect on human development, with no evidence of reverse causality. This shows that the endless fixation on economic growth has manifestly and consistently proven that GDP growth has had sluggish multiplier effect on inclusive development in Zambia. Finally, we draw country‐specific policy recommendations from our empirical findings.
Effect of deposition temperature on the growth mechanism of chemically prepared CZTGeS thin films
Authors: Shamardin A. , Kurbatov D. , Medvids A.
Published: April 2019

The Cu2ZnSnGeS4 (CZTGeS) thin films were deposited by the spray pyrolysis method at different substrate temperatures without further sulfurization. The influence of various deposition temperatures on the surface morphology, microstructure, optical properties, chemical, and phase composition were investigated. The substitution mechanism of Sn/Ge in the crystal lattice of CZTGeS depending on deposition temperatures was studied. It was shown that a variation in substrate temperature has a strong effect on the surface morphology of the films. The X‐ray diffractometer (XRD), transmission electron microscope (TEM), and Raman spectroscopy (RS) analysis showed that CZTGeS films were polycrystalline with a kesterite‐type single‐phase structure and a preferential orientation of (112). The RS‐mapping analysis showed the distribution of intensities on the surfaces of the films. Optical measurements showed that CZTGeS films are highly absorbing in the visible region, and the optical band gap is shifted from 1.89 to 1.84 eV.
Effect of surface modification on the properties of plasma‐polymerized hexamethyldisiloxane thin films
Authors: Saloum Saker , Abou Shaker Samer , Alkafri M.Nidal , Obaid Asmhan , Hussin Rokayya
Published: April 2019

Plasma‐polymerized hexamethyldisiloxane (pp‐HMDSO) thin films have been deposited in a radiofrequency (RF) remote plasma‐enhanced chemical vapor deposition (PECVD) system, on different types of substrates: silicon wafers, glass, quartz crystals, and chemiresistor structure. The as‐grown thin films have been post treated in two types of reactive plasmas produced in SF6 and O2 gases. The effect of this surface modification on different properties of the as‐grown pp‐HMDSO thin film (chemical structure, elemental composition, surface morphology, film density and thickness, optical bandgap, and electrical resistivity) has been investigated. It is found that SF6 plasma and O2 plasma surface modifications of the as‐grown pp‐HMDSO thin film induce property changes different from each other. SF6 plasma converted the as‐grown pp‐HMDSO film to a more porous material and caused a narrowing of its optical band gap of about 33%, while O2 plasma induced a lowering of film electrical resistivity of about two orders of magnitude.
Score tests based on a finite mixture model of Markov processes under intermittent observation
Authors: Jiang Shu , Cook Richard J.
Published: April 2019

A mixture model is described, which accommodates different Markov processes governing disease progression in a finite set of latent classes. We give special attention to the setting in which individuals are examined intermittently and transition times are consequently interval censored. A score test is developed to identify genetic markers associated with class membership. Simulation studies are conducted to validate the algorithm, assess the finite sample properties of the estimators, and assess the frequency properties of the score tests. A permutation test is recommended for settings when there is concern that the asymptotic approximation to the score test is poor. An application involving progression in joint damage in psoriatic arthritis (PsA) provides illustration and identifies human leukocyte antigen markers associated with unilateral and bilateral sacroiliac damage in individuals with PsA.
Effect of Reaction Temperature on the Properties of Polyimide Dielectric Composites
Authors: Mao Xin , Wu Bo , Zhang Fangfang , Wang Chunyan , Deng Ting , Tang Xianzhong
Published: April 2019

Polymer dielectric composites are fabricated by blending polyimide (PI) with poly(vinylidene fluoride) (PVDF) base on different temperature conditions. The dielectric and thermal properties of the composites are studied. Experimental results indicate that the dielectric properties of the composites are enhanced by increasing the reaction temperature, while all the resulted composites exhibit excellent thermal stability. Specifically, the sample showing optimized dielectric properties can be obtained at a reaction temperature of 50 °C.
An In Situ Infrared Study of CO2 Hydrogenation to Formic Acid by Using Rhodium Supported on Titanate Nanotubes as Catalysts
Authors: Ruiz‐García Jesús Roberto , Fierro‐Gonzalez Juan Carlos , Handy Brent E. , Hinojosa‐Reyes Laura , De Haro Del Río David A. , Lucio‐Ortiz Carlos J. , Valle‐Cervantes Sergio , Flores‐Escamilla Gerardo A.
Published: April 2019

Titanate nanotubes (TiNT) were synthesized by hydrothermal method and used as support of rhodium nanoparticles. Results of X‐Ray diffraction (XRD) and Raman spectroscopy of TiNT revealed its structure of Na2Ti3O7, while the results of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and physisorption of N2 confirmed the multilayer nanotubular morphology with external diameter of ∼12 nm, length > 100 nm and a BET surface area of 195 m2 g−1. The TEM analysis of the rhodium supported sample (Rh/TiNT) showed evidence of small (∼1 nm) and highly dispersed rhodium particles. Results of X‐Ray Photoelectron Spectroscopy (XPS) revealed a strong electronic interaction between TiNT and Rh sites. The catalytic activity of Rh/TiNT for the hydrogenation of CO2 to formic acid at moderate temperature (∼40 °C) and atmospheric pressure was demonstrated as evidenced by results of Mass Spectrometry (MS) and in‐situ Diffuse Reflectance Infrared with Fourier Transform Spectroscopy (DRIFTS). The in‐situ studies showed active surface species bonded to support sites and to rhodium sites. It is proposed that under H2 atmosphere, Na+ cations near to Rh particles promote the conversion of CO2 via dissociated H, allowing the formation of formate species at low temperature. The formate species and the hydride rhodium complexes are considered reaction intermediates.
A Solid‐State‐Emissive 1,8‐Naphthalimide Probe Based on Photoinduced Electron Transfer and Aggregation‐Induced Emission
Authors: Georgiev Nikolai I. , Bakov Ventsislav V. , Bojinov Vladimir B.
Published: April 2019

In this work we focused on the design and synthesis of a fluorescence sensing 4‐chloro‐1,8‐naptalimide derivative operating simultaneously by photoinduced electron transfer (PET) and aggregation induced emission (AIE) mechanisms. Absorption and fluorescence properties of the probe were studied as a function of pH in solution and in solid state as compared to the properties of similar 1,8‐naphthalimide derivatives without a substituent at the 1,8‐naphthalimide C‐4 position. The photoinduced fluorescence enhancement of the probe was FE = 22 after protonation in solution (λF = 405 nm, pKa = 8.50±0.08) and FE = 44 (λF = 472 nm) in solid state after reversible exposure on HCl and ammonia vapours due to the amalgamation of monomer emission and AIE. In solid state on paper support the PET process in the probe was switched “off” in a pH window 2.5‐1.5. Due to the remarkable changes in the fluorescence emission the synthesized compound was successfully applied as a solid‐state chemosensing material for rapid detection of acid‐base vapours and pH in aqueous solutions. The concept proposed herein could drive the classic AIE and PET molecular sensors towards new directions and practical applications.
Synthesis of Flower‐Like Carbon‐Doped Nickel Phosphides Electrocatalysts for Oxygen Evolution Reaction
Authors: Cheng Xian , Zheng Jianfeng , Li Jintang , Luo Xuetao
Published: April 2019

Motivated by the challenge to find a low‐cost catalyst with efficient activity for the oxygen evolution reaction (OER), transition metal phosphides (TMPs) recently have been gained attentions as promising earth‐abundant alternatives to nobel metal based electrocatalysts. Here, we present a facile strategy for the synthesis of flower‐like carbon doped nickel phosphides (NiP/C) for OER catalysis, which templated by nickel phenylphosphonate through thermal treatment under H2(5%)/Ar. The phenylphosphonic acid ligand used here has excellent affinity toward metal ions and thus can act as P and C source at the molecular scale. Benefiting from the incorporation of conductive carbon and higher Ni atomic percentage provide more active sites, the sample denoted as NiP/C‐850 exhibits outstanding electrocatalytic activity, with a lower overpotential of 290 mV to achieve the current density of 10 mA⋅cm−2, a small Tafel slope of 74 mV⋅dec−1 and superior durability in 1.0 M KOH solution. This work provides insights for the rich metal organophosphonate chemistry for fabricating carbon doped metal phosphides applied to the electrochemical conversion technologies.
Steric Clashes, Doughnuts and Exploding Cigars: Some Comments on Non‐Covalent Interactions
Authors: Lomas John S.
Published: April 2019

Isosurfaces appearing in three‐dimensional Non‐Covalent Interactions (NCI) representations of molecules are attributed to bonding interactions (sign(λ2)*ρ < 0) or to non‐bonding interactions, often referred to as “steric clashes” and typical of ring systems (sign(λ2)*ρ > 0). Since the second eigenvalue of the Hessian of the electron density, λ2, is positive for a ring or a cage critical point and negative for a bond critical point, in many cases NCI isosurfaces simply surround QTAIM critical points, which means that the attribution of positive‐λ2 isosurfaces to steric clashes in rings or cages is not justified. Examples are given for sterically congested hydrocarbons, where isosurfaces associated with C–H…H–C interactions enclose bond and ring critical points. In the same way, their appearance in the absence of critical points can be attributed to a variation of λ2. It is shown that for small, very strained rings, positive‐λ2 isosurfaces are not found when the recommended plot parameters are used.
Enantiospecific Synthesis of 2‐Substituted Piperidine‐4‐carboxylic Acids from α‐Amino Acids
Authors: Ramesh Subbiah , Balakumar Ramadas , Rizzo John R. , Zhang Tony Y.
Published: April 2019

A feasible route to access chiral 2‐substituted piperidine‐4‐carboxylic acids as versatile pharmaceutical intermediates was established from easily accessible N‐Cbz amino acids derivatives and Meldrum's acid in simple synthetic sequence. The relatively broad scope was demonstrated by the synthesis of various 2‐substituted piperidine‐4‐carboxylic acids and exemplified in the selective synthesis of AZD6564, a fibrinolysis inhibitor.
Mild Hydrogenation of Urban Biowaste Hydrolysates to Biopolymers with Improved Properties.
Authors: Montoneri Enzo , Fabbri Gloria , Grillo Giorgio , Tabasso Silvia , Cravotto Giancarlo , Quagliotto Pierluigi , Baglieri Andrea , Boero Valter , Negre Michèle
Published: April 2019

This work reports the hydrogenation of soluble biopolymers (SBP) obtained by hydrolysis of municipal biowaste anaerobic digestate (D) and compost (CP). The SBP are mix of heterogenous molecules with 5–750 kDa molecular weight constitued by aliphatic and aromatic C moieties substitued by acid and basic functional groups. They are mutipurpose products for use in the chemical industry as biosurfactants and plastics’ additives, in agriculture and in animal husbandry. Purpose of hydrogenation was to improve SBP properties, while keeping macromolecularity. Hydrogenation was carried out in 4–5% water solution at pH 10 at 100 °C and 35 bar H2 pressure for 2–30 min. Results show hydrogenation of up to 35% SBP C to products containing more aliphatic C and different molecular weight distribution. Relative to pristine SBP, the molecular weight of hydrogenated CP SBP and of D SBP are, respectively, higher and lower. Surfactants properties improve upon hydrogenation. Hydrogenated D SBP are better surfactants than hydrogenated CP SBP. Further improvement and uses of hydrogenated SBP are discussed.
Synthesis and Characterization of Fluorescent Carbon Dots from Tapioca
Authors: Pudza Musa Y. , Abidin Zurina Z. , Abdul‐Rashid Suraya , Yassin Faizah Md. , Noor Ahmad S. M , Abdullah Mohammed
Published: April 2019

This research demonstrates an economical and efficient reduction of carbon foot print. Tapioca powder as a source of organic carbon was utilized in the synthesis of carbon dots through optimization of the synthesis parameters such as temperature, dosage and time. Photoluminescent quantum yield (PLQY) was obtained under the visible region of 340 nm at 34.9%, which was achieved without dopants such as sulfur and nitrogen that are popularly used to increase the value of photoluminescence. The characterization of carbon dots such as FTIR and HrTem, were carried out for the analysis of functional groups, particle sizes (1‐5 nm) and shapes (quasi‐spherical). The high carbon‐carbon bonds and oxygen groups detected in FTIR analysis validates the basis of fluorescence of carbon dots and also presence of hydroxyl (OH), carboxylic acids (COO), and other vital functional groups (C=O, C−O‐C, C−H). These characteristics makes tapioca based carbon dots suitable for application in the fields of environmental studies including sensitive detection and absorbance of pollutants in water and bio imaging in health sciences.
Intrinsically Optimizing Charge Transfer via Tuning Charge/Discharge Mode for Lithium–Oxygen Batteries
Authors: Liu Wei , Shen Yue , Yu Yao , Lu Xia , Zhang Wang , Huang Zhaoming , Meng Jintao , Huang Yunhui , Guo Zaiping
Published: April 2019

Lithium–oxygen batteries have an ultrahigh theoretical energy density, almost ten times higher than lithium‐ion batteries. The poor conductivity of the discharge product Li2O2, however, severely raises the charge overpotential and pulls down the cyclability. Here, a simple and effective strategy is presented for regular formation of lithium vacancies in the discharge product via tuning charge/discharge mode, and their effects on the charge transfer behavior. The effects of the discharge current density on the lithium vacancies, ionic conductivity, and electronic conductivity of the discharge product Li2O2 are systematically investigated via electron spin resonance, spin‐alignment echo nuclear magnetic resonance, and tungsten nanomanipulators, respectively. The study by density functional theory indicates that the lithium vacancies in Li2O2 generated during the discharge process are highly dependent on the current density. High current can induce a high vacancy density, which enhances the electronic conductivity and reduces the overpotential. Meanwhile, with increasing discharge current, the morphology of the Li2O2 changes from microtoroids to thin nanoplatelets, effectively shortening the charge transfer distance and improving the cycling performance. The Li2O2 grown in fast discharge mode is more easily decomposed in the following charging process. The lithium–oxygen battery cycling in fast‐discharge/slow‐charge mode exhibits low overpotential and long cycle life.
Polyproline Tri‐Helix Macrocycles as Nanosized Scaffolds to Control Ligand Patterns for Selective Protein Oligomer Interactions
Authors: Lin Cin‐Hao , Wen Hsin‐Chuan , Chiang Cheng‐Chin , Huang Jen‐Sheng , Chen Yunching , Wang Sheng‐Kai
Published: April 2019

Multivalent ligand–receptor interactions play essential roles in biological recognition and signaling. As the receptor arrangement on the cell surface can alter the outcome of cell signaling and also provide spatial specificity for ligand binding, controlling the presentation of ligands has become a promising strategy to manipulate or selectively target protein receptors. The lack of adjustable universal tools to control ligand positions at the size of a few nanometers has prompted the development of polyproline tri‐helix macrocycles as scaffolds to present ligands in designated patterns. Model lectin Helix pomatia agglutinin has shown selectivity toward the matching GalNAc ligand pattern matching its binding sites arrangement. The GalNAc pattern selectivity is also observed on intact asialoglycoprotein receptor oligomer on human hepatoma cells showing the pattern‐selective interaction can be achieved not only on isolated protein oligomers but also the receptors arranged on the cell surface. As the scaffold design allows convenient creation of versatile ligand patterns, it can be expected as a promising tool to probe the arrangement of receptors on the cell surface and as nanomedicine to manipulate signaling or cell recognition.
Flexible Micropillar Electrode Arrays for In Vivo Neural Activity Recordings
Authors: Du Mingde , Guan Shouliang , Gao Lei , Lv Suye , Yang Siting , Shi Jidong , Wang Jinfen , Li Hongbian , Fang Ying
Published: April 2019

Flexible electronics that can form tight interfaces with neural tissues hold great promise for improving the diagnosis and treatment of neurological disorders and advancing brain/machine interfaces. Here, the facile fabrication of a novel flexible micropillar electrode array (µPEA) is described based on a biotemplate method. The flexible and compliant µPEA can readily integrate with the soft surface of a rat cerebral cortex. Moreover, the recording sites of the µPEA consist of protruding micropillars with nanoscale surface roughness that ensure tight interfacing and efficient electrical coupling with the nervous system. As a result, the flexible µPEA allows for in vivo multichannel recordings of epileptiform activity with a high signal‐to‐noise ratio of 252 ± 35. The ease of preparation, high flexibility, and biocompatibility make the µPEA an attractive tool for in vivo spatiotemporal mapping of neural activity.
Highly Reproducible Physiological Asymmetric Membrane with Freely Diffusing Embedded Proteins in a 3D‐Printed Microfluidic Setup
Authors: Heo Paul , Ramakrishnan Sathish , Coleman Jeff , Rothman James E. , Fleury Jean‐Baptiste , Pincet Frederic
Published: April 2019

Experimental setups to produce and to monitor model membranes have been successfully used for decades and brought invaluable insights into many areas of biology. However, they all have limitations that prevent the full in vitro mimicking and monitoring of most biological processes. Here, a suspended physiological bilayer‐forming chip is designed from 3D‐printing techniques. This chip can be simultaneously integrated to a confocal microscope and a path‐clamp amplifier. It is composed of poly(dimethylsiloxane) and consists of a ≈100 µm hole, where the horizontal planar bilayer is formed, connecting two open crossed‐channels, which allows for altering of each lipid monolayer separately. The bilayer, formed by the zipping of two lipid leaflets, is free‐standing, horizontal, stable, fluid, solvent‐free, and flat with the 14 types of physiologically relevant lipids, and the bilayer formation process is highly reproducible. Because of the two channels, asymmetric bilayers can be formed by making the two lipid leaflets of different composition. Furthermore, proteins, such as transmembrane, peripheral, and pore‐forming proteins, can be added to the bilayer in controlled orientation and keep their native mobility and activity. These features allow in vitro recapitulation of membrane process close to physiological conditions.
Artificial Photosynthesis with Polymeric Carbon Nitride: When Meeting Metal Nanoparticles, Single Atoms, and Molecular Complexes
Authors: Li Yanrui , Kong Tingting , Shen Shaohua
Published: April 2019

Artificial photosynthesis for solar water splitting and CO2 reduction to produce hydrogen and hydrocarbon fuels has been considered as one of the most promising ways to solve increasingly serious energy and environmental problems. As a well‐documented metal‐free semiconductor, polymeric carbon nitride (PCN) has been widely used and intensively investigated for photocatalytic water splitting and CO2 reduction, owing to its physicochemical stability, visible‐light response, and facile synthesis. However, PCN as a photocatalyst still suffers from the fast recombination of electron‐hole pairs and poor water redox reaction kinetics, greatly restricting its activity for artificial photosynthesis. Among the various modification approaches developed so far, decorating PCN with metals in different existences of nanoparticles, single atoms and molecular complexes, has been evidently very effective to overcome these limitations to improve photocatalytic performances. In this Review article, a systematic introduction to the state‐of‐the‐art metal/PCN photocatalyst systems is given, with metals in versatility of nanoparticles, single atoms, and molecular complexes. Then, the recent processes of the metal/PCN photocatalyst systems in the applications of artificial photosynthesis, e.g., water splitting and CO2 reduction, are reviewed. Finally, the remaining challenges and opportunities for the development of high efficiency metal/PCN photocatalyst systems are presented and prospected.
Modulation of Bi2MoO6‐Based Materials for Photocatalytic Water Splitting and Environmental Application: a Critical Review
Authors: Yu Hanbo , Jiang Longbo , Wang Hou , Huang Binbin , Yuan Xingzhong , Huang Jinhui , Zhang Jin , Zeng Guangming
Published: April 2019

Highly active photocatalysts driving chemical reactions are of paramount importance toward renewable energy substitutes and environmental protection. As a fascinating Aurivillius phase material, Bi2MoO6 has been the hotspot in photocatalytic applications due to its visible light absorption, nontoxicity, low cost, and high chemical durability. However, pure Bi2MoO6 suffers from low efficiency in separating photogenerated carriers, small surface area, and poor quantum yield, resulting in low photocatalytic activity. Various strategies, such as morphology control, doping/defect‐introduction, metal deposition, semiconductor combination, and surface modification with conjugative π structures, have been systematically explored to improve the photocatalytic activity of Bi2MoO6. To accelerate further developments of Bi2MoO6 in the field of photocatalysis, this comprehensive Review endeavors to summarize recent research progress for the construction of highly efficient Bi2MoO6‐based photocatalysts. Furthermore, benefiting from the enhanced photocatalytic activity of Bi2MoO6‐based materials, various photocatalytic applications including water splitting, pollutant removal, and disinfection of bacteria, were introduced and critically reviewed. Finally, the current challenges and prospects of Bi2MoO6 are pointed out. This comprehensive Review is expected to consolidate the existing fundamental theories of photocatalysis and pave a novel avenue to rationally design highly efficient Bi2MoO6‐based photocatalysts for environmental pollution control and green energy development.
Cloud‐based healthcare management: Identifying the privacy concerns and their moderating effect on the cloud‐based health‐care services
Authors: Misra Subhas C. , Kumar Ashutosh , Munnangi Aswani K.
Published: April 2019

This article studies about cloud healthcare management, where the cloud computing services seems as one of the viable options to improve the health‐care services but simultaneously faces certain deterrents in the form of privacy concerns of the service users. This study aims to identify the privacy concerns, followed by analyzing the moderating effect of these concerns over the success parameters which favors the successful adoption of cloud‐based healthcare services. A total of 20 success parameters and nine privacy concerns of cloud‐based healthcare service users have been identified by doing a thorough literature review. The success parameters are the independent variables, privacy concerns are the moderating variables, and the factors defining success measures are the dependent variables. These three types of variables have been constituted to propose three models which identify the direct as well as the moderating effect of these privacy concerns over the critical success factors (CSFs) for the successful adoption of cloud‐based healthcare services. These have been factually tested by analysis done on data collected from 105 respondents of the related domain. Structural equation modeling has been used to determine the moderating effect of the privacy concerns over the success factors. The latent variables used in the models successfully pass discriminant validity, composite reliability, multicollinearity, indicator correlation, and factor analysis test. The observed outcome demonstrates that privacy concerns of cloud‐based healthcare service users are moderating the organizational and people‐related success factors, whereas it does not moderate the technology‐related success factors for successful adoption of cloud‐based healthcare services. The privacy concerns of such service users and the CSFs (ie, organizational‐, people‐, technology‐related success factors) directly and significantly affect the adoption rate of cloud‐based healthcare services. Thus the article produces a data‐based proof and statistically analyzed basis for the companies and healthcare organizations involved in the development and maintenance of cloud‐based healthcare services by categorically breaking down the effect of success parameters of cloud adoption along with pointing out the concerns to be addressed to convincingly satisfy the service users.
Numerische Untersuchungen einer energiedissipierenden Schutzvorrichtung gegen Schiffsanprall
Authors: Morgenthal Guido , Wang Wei , Kraus Matthias
Published: April 2019

Herrn Univ.‐Prof. Dr.‐Ing. habil. Frank Werner zur Vollendung seines 70. Lebensjahres gewidmet

Ein Schiffsanprall stellt eine außergewöhnliche Beanspruchungssituation dar, die die Sicherheit von Brückenbauwerken im Bereich von Wasserstraßen gefährdet. Zur Vermeidung des unmittelbaren Anpralls gegen Brückenpfeiler kommen unterschiedliche Schutzvorrichtungen zum Einsatz. Derartige Schutzsysteme dissipieren einen Großteil der Anprallenergie durch die Entwicklung plastischer Deformationen, sodass die vom Pfeiler bzw. Schiff zu absorbierende Energie auf ein Minimum reduziert wird. In diesem Beitrag werden numerische Untersuchungen und das strukturelle Verhalten einer neuartigen kollisionssichernden Konstruktion vorgestellt, bei der sich beim Anprall plastische Mechanismen in klar definierten Bauteilbereichen entwickeln und übrige Konstruktionselemente im elastischen Zustand verbleiben. Da die Konstruktion nach einem Anprallereignis dadurch in weiten Bereichen nicht geschädigt ist, können sich Wiederherstellungsmaßnahmen auf lokal begrenzte Bereiche beschränken. Die konstruktive Durchbildung von Konstruktionsdetails steht bei den Untersuchungen nicht im Mittelpunkt und soll in weitergehenden Studien entwickelt werden.
A dialogic approach to exploring culture in community‐based adult ESL classrooms
Authors: Shufflebarger Snell Amanda Marie
Published: April 2019

Despite the robust literature about teaching intercultural competence, little has been written on exploring culture in community‐based English as a second language (ESL) settings, such as classes for adults with immigrant and refugee backgrounds. Educational materials about culture designed for these contexts tend to be prescriptive and essentializing, displaying rules and norms without inviting dialogue or accounting for variation. This article addresses this gap by dialogically exploring perceptions of adults in a community‐based ESL class toward cultural themes, with the goal of moving toward reflective pedagogy about culture in community‐based ESL contexts. Data, which were collected throughout a 14‐week course, include surveys about students’ perceived cultural knowledge, interest in learning about culture, and comfort interacting with Americans, as well as student‐produced texts and responses to texts exploring cultural themes. Students were eager to dialogue about culture, and they indicated increased cultural understanding and interest after the 14‐week course, as well as interest in forming more intercultural relationships. The article presents examples of student‐produced texts and invites instructors to consider how to reflectively choose materials, teach, and dialogue about culture in community‐based ESL classes.
Ultrasound feedback training increases trainee accuracy in vaginal assessment of fetal head position in labor
Authors: Goldkamp J. , Vricella L. , Mostello D. , Tomlinson T.
Published: April 2019

Objective

To evaluate the impact of an immediate ultrasound feedback intervention on trainee accuracy in vaginal‐examination‐based assessment of fetal head position.

Methods

This was a prospective cohort study conducted at a single tertiary care center. Six third‐year and six fourth‐year residents in an obstetrics and gynecology residency training program were the study subjects. The third‐year residents underwent a training intervention in which they assessed fetal head position by transvaginal digital examination and then received immediate feedback through ultrasound demonstration of the actual position. All examinations were performed in women with a singleton gestation ≥ 35 weeks and cervical dilation ≥ 8 cm, following rupture of membranes. The comparison groups were third‐year residents before, during and after training and fourth‐year residents who were not exposed to the training intervention. The primary outcome was the difference in accuracy of fetal‐head‐position assessment on vaginal examination by third‐year residents before and after ultrasound feedback training. Univariate and multivariate analyses were performed to identify factors associated with digital examination accuracy.

Results

Overall, 390 examinations were performed. The accuracy of fetal‐head‐position assessments of third‐year residents was 55% (53/96) before training, 65% (74/114) during training and 70% (63/90) after training, while that of fourth‐year residents who did not undergo training was 52% (47/90) (P = 0.04). Fourth‐year residents who did not undergo ultrasound training demonstrated similar baseline accuracy to that of third‐year residents pretraining (52% (47/90)vs55% (53/96),P = 0.68), but had significantly lower accuracy than had the third‐year residents post‐training (52% (47/90)vs70% (63/90);P = 0.01). Multivariable analysis revealed a positive association between ultrasound feedback training and the ability to assess accurately fetal head position. After adjusting for the variables included in the final model, examinations performed by third‐year residents pretraining and those performed by fourth‐year residents who did not undergo training were less likely to be accurate than those performed by third‐year residents post‐training (adjusted odds ratio, 0.48 (95% CI, 0.26–0.91) and 0.42 (95% CI, 0.22–0.80), respectively).

Conclusion

Immediate ultrasound feedback training increased trainee accuracy in vaginal assessment of fetal head position in labor. Its integration into obstetric training programs should be considered. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.