bluuebunny/crossref_metadata_2025 huggingface dataset:
Folate‐Conjugated and Dual Stimuli‐Responsive Mixed Micelles Loading Indocyanine Green for Photothermal and Photodynamic Therapy
Authors: Chien Yu‐Ying , Wang Tung‐Yun , Liao Po‐Wen , Wu Wen‐Chung , Chen Ching ‐Yi
Published: May 2018

A folic acid targeted mixed micelle system based on co‐assembly of poly(ε‐caprolactone)‐b‐poly(methoxytri(ethylene glycol) methacrylate‐co‐N‐(2‐methacrylamido)ethyl folatic amide) and poly(ε‐caprolactone)‐b‐poly(diethylene glycol monomethyl ether methacrylate) is developed to encapsulate indocyanine green (ICG) for photothermal therapy and photodynamic therapy. In this study, the use of folic acid is not only for specific cancer cell recognition, but also in virtue of the carboxylic acid on folic acid to regulate the pH‐dependent thermal phase transition of polymeric micelles for controlled drug release. The prepared ICG‐loaded mixed micelles possess several superior properties such as a preferable thermoresponsive behavior, excellent storage stability, and good local hyperthermia and reactive oxygen species generation under near‐infrared (NIR) irradiation. The photototoxicity induced by the ICG‐loaded micelles has efficiently suppressed the growth of HeLa cells (folate receptor positive cells) under NIR irradiation compared to that of HT‐29, which has low folate receptor expression. Hence, this new type of mixed micelles with excellent features could be a promising delivery system for controlled drug release, effective cancer cell targeting, and photoactivated therapy.
Liposomes‐Camouflaged Redox‐Responsive Nanogels to Resolve the Dilemma between Extracellular Stability and Intracellular Drug Release
Authors: Ma Jinfeng , Deng Hongzhang , Zhao Fuli , Deng Liandong , Wang Weiwei , Dong Anjie , Zhang Jianhua
Published: May 2018

Liposomes have shown great promises for pharmaceutical applications, but still suffer from the poor storage stability, undesirable drug leakage, and uncontrolled drug release. Herein, liposomes‐camouflaged redox‐responsive nanogels platform (denoted as “R‐lipogels”) is prepared to integrate the desirable features of sensitive nanogels into liposomes to circumvent their intrinsic issues. The results indicate that drug‐loaded R‐lipogels with controlled size and high stability not only can achieve a very high doxorubicin (DOX)‐loading capacity (12.9%) and encapsulation efficiency (97.3%) by ammonium sulfate gradient method and very low premature leakage at physiological condition, but also can quickly release DOX in the reducing microenvironment of tumor cells, resulting in effective growth inhibition of tumor cells. In summary, the strategy given here provides a facile approach to develop liposomes–nanogels hybrid system with combined beneficial features of stealthy liposomes and responsive nanogels, which potentially resolves the dilemma between systemic stability and intracellular rapid drug release.
Polyimide/Graphene Nanocomposites with Improved Gas Barrier and Thermal Properties due to a “Dual‐Plane” Structure Effect
Authors: Liu Yiwu , Liu Junjie , Ding Qian , Tan Jinghua , Chen Zhiquan , Chen Junyi , Zuo Xuri , Tang Ao , Zeng Kejian
Published: May 2018

Graphene nanosheets are prepared by solution‐phase exfoliation of graphite and successfully incorporated with polyimide to obtain polyimide/graphene (DABPI/G) nanocomposites via in situ polymerization. Compared with those of pure DABPI, the DABPI/G nanocomposites exhibit better barrier and thermal properties. The oxygen and water vapor transmission rates of the DABPI/G (0.5 wt%) nanocomposite are 0.69 cm3m−2d−1and 0.44 g m−2d−1, respectively, which are 92 and 85% lower than those of pure DABPI. Meanwhile, the DABPI/G (0.5 wt%) nanocomposite exhibits excellent thermal stability with a Td5%of 578 °C and a coefficient of thermal expansion of −0.19 ppm K−1. The excellent barrier and thermal properties of DABPI/G nanocomposites are mainly attributed to the fine dispersion and orientation of the graphene nanosheets, increased crystallinity, and low free volume of the DABPI matrix. These are the result of the “dual‐plane” structure effect, which is the synergistic orientation effect between the rigid planar molecular chains of DABPI and the nanosheets of graphene.
Nanocrystalline Cellulose for Anisotropic Magnetoelectric Composites
Authors: Zong Yan , Yue Zhilian , Higgins Michael J.
Published: May 2018

The emergence of piezoelectric polymers in magnetoelectric (ME) composites enables flexible and low‐cost device fabrication though notably gives rise to the highest ME output voltages to date. Accordingly, the highest piezoresponsive polymers, poly(vinylidene fluoride) (PVDF) and its copolymers, are exclusively studied despite an inventory of unexplored piezoelectric polymers such as naturally occurring cellulose, that is only recently demonstrated in ME composites. Herein, the development of nanocrystalline cellulose (CNC)‐based ME composites is reported on. Two types of CNC, nanospheres and nanowhiskers, are synthesized and incorporated in laminate composite, which exhibit a giant αME (>1 V cm−1 Oe−1). By successfully reconstructing the orientated cellulose fibril structures found in natural plants using spinning‐induced alignment of CNC nanowhiskers, an anisotropic effect originating from the piezoelectric phase in ME composites is attained. The anisotropic effect produces output voltages an order of magnitude higher than those in current polymer‐based particulate ME vector sensing composites with 0–3 configurations.
Scaffolds with Tunable Properties Constituted by Electrospun Nanofibers of Polyglycolide and Poly(ε‐caprolactone)
Authors: Keridou Ina , Franco Lourdes , Turon Pau , del Valle Luís J. , Puiggalí Jordi
Published: May 2018

Electrospun scaffolds constituted by different mixtures of two biodegradable polyesters are prepared. Specifically, materials with well differentiated properties can be derived from the blending of hydrophilic polyglycolide (PGA) and hydrophobic poly(ε‐caprolactone) (PCL), which are also two of the most applied polymers for biomedical uses. Electrospinning conditions are selected in order to get homogeneous and continuous fibers with diameters in the nano/micrometric range. These conditions are also applied to load the different scaffolds with curcumin (CUR) and polyhexamethylene biguanide (PHMB) as hydrophobic and hydrophilic bactericide compounds, respectively. Physicochemical characterization of both unloaded and loaded scaffolds is performed and involved Fourier transform infrared and 1H NMR spectroscopies, morphological observations by scanning electron microscopy, study of thermal properties through calorimetry and thermogravimetric analysis, and evaluation of surface characteristics through contact angle measurements. Release behavior of the loaded scaffolds is evaluated in two different media. Results point out a well differentiated behavior where the delivery of CUR and even PHMB are highly dependent on the PGA/PCL ratio, the capability of the medium to swell the polymer matrix, and the diffusion of the selected solvent into the electrospun fibers. All samples show a bactericide effect in both hydrophilic cell culture and hydrophobic agar media.
Complex interpolation of Herz‐type Triebel–Lizorkin spaces
Authors: Drihem Douadi
Published: May 2018

We study complex interpolation of Herz‐type Triebel–Lizorkin spaces by using the Calderón product method. Additionally we present complex interpolation between Herz‐type Triebel–Lizorkin spaces and Triebel–Lizorkin spaces . Moreover, we apply these results to obtain the complex interpolation of Triebel–Lizorkin spaces equipped with power weights and between (or ) spaces and Herz spaces.
Conformational Changes and Dynamics during Adsorption of Macromolecules with Different Degree of Polymerization Studied by Monte Carlo Simulations
Authors: Sabater i Serra Roser , Torregrosa Cabanilles Constantino , Meseguer Dueñas José María , Gómez Ribelles José Luis , Molina‐Mateo José
Published: May 2018

Dynamics of multilayer adsorption of macromolecules with different degree of polymerization is studied by coarse‐grained Monte Carlo simulations, focusing on both the interface macromolecule‐surface and chain–chain interaction in and out of equilibrium conditions. The interfacial interaction between the solid flat surface and the macromolecules is modeled by means of a Lennard–Jones potential, and inter‐ and intrachain interactions are simulated using bond angle, bond length, and Lennard–Jones potentials. The results show that local and conformational motions near the glass transition temperature promote configurations with minimal energy, which induce better space efficiency and favor aligned conformations at the interface. In this context, it is also found that restriction of movement, together with the connectivity effect exerted by the partially adsorbed segments, leads to a range of chain lengths that maximizes the molecular groups adsorbed.
Chimeric HDAC inhibitors: Comprehensive review on the HDAC‐based strategies developed to combat cancer
Authors: Hesham Heba M. , Lasheen Deena S. , Abouzid Khaled A.M.
Published: May 2018

Recently, molecular hybridization paradigm became an interesting and smart way to defeat the multifaceted cancer disease by a single molecular entity that acts via several mechanisms just like a magic bullet. Also, HDAC is an important epigenetic target in drug discovery, and the HDAC inhibitors showed successful pattern as cytotoxic agents. Because of their flexible structure activity relationship, it was easy to link them to other anticancer scaffolds. So, many dual action HDAC inhibitors have been developed and most of these hybrids have higher potency than the constituting parents in fighting of the cancer cells. This review describes potential applications of chimeric HDAC inhibitors, which simultaneously modulate not only HDAC but also multiple targets, in treatment of relapsing and drug‐resistant cancers. We have nearly collected most of the reported dual action HDAC inhibitors yet to provide a comprehensive guide for the drug discovery process for developing more efficient anticancer agents.
Modeling of Semibatch Solution Radical Copolymerization of Butyl Methacrylate and 2‐Hydroxyethyl Acrylate
Authors: Schier Jan E. S. , Zhang Min , Grady Michael C. , Hutchinson Robin A.
Published: May 2018

Nonfunctional monomer feedstocks containing alkyl meth(acrylate) components such as butyl acrylate (BA) and butyl methacrylate (BMA) are replaced or augmented with functional monomers such as 2‐hydroxyethyl methacrylate (HEMA) and 2‐hydroxyethyl acrylate (HEA) to produce reactive polymer chains of lowered molar mass for application in solvent‐borne automotive coatings. The introduction of such polar and functional reactants affects the radical copolymerization kinetics and introduces solvent dependencies. A series of BMA/HEA experiments are performed to determine the influence of these changing kinetic parameters under starved‐feed semibatch operating conditions. A comparison with BMA/BA copolymerizations shows that the influence of hydrogen bonding is small, with the semibatch system well controlled to HEA contents of up to 50 wt%. Thus, the experiments are well represented by a comprehensive generalized copolymerization model that considers relevant methacrylate and acrylate side‐reactions and uses the chain growth parameters measured in previous kinetic investigations.
The Effect of Water Temperature, Angling Time, and Dissolved Oxygen on the Survival of Largemouth Bass Subjected to Simulated Angling and Tournament Handling Procedures
Authors: Keretz Kevin R. , Dinken Colin P. , Allen Peter J. , Colvin Michael E. , Schramm Harold L.
Published: May 2018

The Largemouth Bass Micropterus salmoides is the most sought-after species by recreational and tournament anglers in the United States. Survival of angled and tournament-handled Largemouth Bass has been related to numerous factors, but the independent effects of water temperature, angling time, and live-well dissolved oxygen (DO) concentration on survival have not been measured. Understanding the independent effects of these factors on fish survival is necessary to formulate realistic models to predict population effects of catch-and-release and tournament angling throughout the year. Survival responses to water temperature, angling time, and live-well DO concentration are also needed to develop guidelines useful for maximizing survival of released Largemouth Bass. Five-day survival of Largemouth Bass larger than 300 mm was evaluated after simulated catch-and-release and tournament handling (8 h of confinement in aerated live wells and a weigh-in before release) over the range of water temperatures typically encountered by Largemouth Bass anglers (17–33°C) while also testing independent effects of simulated angling time (1 and 3 min), live-well temperature change (∆T = 0, −4, and +4°C), and live-well DO (2.0, 5.5, and 8.5 mg/L). Survival of fish subjected to catch and immediate release was 100% at all temperatures measured, and survival of tournament-caught fish was over 80% at temperatures of 29°C or less but declined at 33°C. Survival decreased with increased simulated angling time at high temperatures and at a DO level of 2.0 mg/L in live wells. Survival rates and probabilities provided in this study should be considered best-case estimates because all fish were handled carefully and not subjected to hook wounding. However, results suggest that high survival of angled and tournament-handled Largemouth Bass is possible with short angling times and appropriate live-well management.
A novel scaled boundary finite element formulation with stabilization and its application to image‐based elastoplastic analysis
Authors: He Ke , Song Chongmin , Ooi Ean Tat
Published: May 2018

Digital images are increasingly being used as input data for computational analyses. This study presents an efficient numerical technique to perform image‐based elastoplastic analysis of materials and structures. The quadtree decomposition algorithm is employed for image‐based mesh generation, which is fully automatic and highly efficient. The quadtree cells are modeled by scaled boundary polytope elements, which eliminate the issue of hanging nodes faced by standard finite elements. A novel, simple, and efficient scaled boundary elastoplastic formulation with stablisation is developed. In this formulation, the return‐mapping calculation is only required to be performed at a single point in a polytope element, which facilitates the computational efficiency of the elastoplastic analysis and simplicity of implementation. Numerical examples are presented to demonstrate the efficiency and accuracy of the proposed technique for performing the elastoplastic analysis of high‐resolution images.
CD206‐positive myeloid cells bind galectin‐9 and promote a tumor‐supportive microenvironment
Authors: Enninga Elizabeth Ann L , Chatzopoulos Kyriakos , Butterfield John T , Sutor Shari L , Leontovich Alexey A , Nevala Wendy K , Flotte Thomas J , Markovic Svetomir N
Published: May 2018

In patients with metastatic melanoma, high blood levels of galectin‐9 are correlated with worse overall survival and a bias towards a Th2 inflammatory state supportive of tumor growth. Although galectin‐9 signaling through TIM3 on T cells has been described, less is known about the interaction of galectin‐9 with macrophages. We aimed to determine whether galectin‐9 is a binding partner of CD206 on macrophages and whether the result of this interaction is tumor‐supportive. It was determined that incubation of CD68+ macrophages with galectin‐9 or anti‐CD206 blocked target binding and that both CD206 and galectin‐9 were detected by immunoprecipitation of cell lysates. CD206 and galectin‐9 had a binding affinity of 2.8 × 10−7 m. Galectin‐9 causes CD206+ macrophages to make significantly more FGF2 and monocyte chemoattractant protein (MCP‐1), but less macrophage‐derived chemokine (MDC). Galectin‐9 had no effect on classical monocyte subsets, but caused expansion of the non‐classical populations. Lastly, there was a positive correlation between increasing numbers of CD206 macrophages and galectin‐9 expression in tumors, and high levels of CD206 macrophages correlated negatively with melanoma survival. These results indicate that galectin‐9 binds to CD206 on M2 macrophages, which appear to drive angiogenesis and the production of chemokines that support tumor growth and poor patient prognoses. Targeting this interaction systemically through circulating monocytes may therefore be a novel way to improve local anti‐tumor effects by macrophages. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Small RNA and transcriptome sequencing reveal the role of miR‐199a‐3p in inflammatory processes in cystic fibrosis airways
Authors: Bardin Pauline , Marchal‐Duval Emmeline , Sonneville Florence , Blouquit‐Laye Sabine , Rousselet Nathalie , Le Rouzic Philippe , Corvol Harriet , Tabary Olivier
Published: May 2018

Cystic fibrosis (CF) is the most common lethal genetic disease, caused by CFTR (cystic fibrosis transmembrane conductance regulator) gene mutations. CF is characterized by an ionic imbalance and thickened mucus, which impair mucociliary clearance and promote bacterial colonization and the establishment of infection/inflammation cycles. However, the origin of this inflammation remains unclear, although microRNAs (miRNAs) are suspected to be involved. MiRNAs are small non‐coding RNAs that bind to the 3′‐untranslated regions (UTRs) of target gene mRNA, thereby repressing their translation and/or inducing their degradation. The goal of this study was to investigate the role of microRNAs associated with pulmonary inflammation in CF patients. Through the analysis of all miRNAs (miRNome) in human primary air–liquid interface cultures, we demonstrated that miR‐199a‐3p is the only miRNA downregulated in CF patients compared to controls. Moreover, through RNA sequencing (transcriptome) analysis, we showed that 50% of all deregulated mRNAs are linked directly or indirectly to the NF‐κB pathway. To identify a specific target, we used bioinformatics analysis to predict whether miR‐199a‐3p targets the 3′‐UTR of IKBKB, which encodes IKKβ, a major protein in the NF‐κB pathway. Subsequently, we used bronchial explants from CF patients to show that miR‐199a‐3p expression is downregulated compared to controls and inversely correlated with increases in expression of IKKβ and IL‐8. Through functional studies, we showed that miR‐199a‐3p modulates the expression of IKBKB through a direct interaction at its 3′‐UTR in bronchial epithelial cells from CF patients. In miR‐199a‐3p overexpression experiments, we demonstrated that for CF cells, miR‐199a‐3p reduced IKKβ protein expression, NF‐κB activity, and IL‐8 secretion. Taken together, our findings show that miR‐199a‐3p plays a negative regulatory role in the NF‐κB signalling pathway and that its low expression in CF patients contributes to chronic pulmonary inflammation. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Experimental optimization and static characterization of modified fiber metal laminates with integrated mechanical interlock bonding system for aerospace applications
Authors: Nong Tran‐Vu , ElSayed Mostafa S.A. , Biseul Camille
Published: May 2018

This article presents a modified version of fiber metal laminates with integrated mechanical interlock bonding system for aerospace applications. Sheet metals of Al 2024‐T3 with surface machined infinitesimal hooks are used along with impregnated glass fiber composites to manufacture a modified version of GLAss REinforced aluminum (GLARE). Static performance of the modified GLARE is examined through tensile, in‐plane shearing, and three‐point flexural bending tests. To optimize the geometry of the machined hooks to maximize the modified GLARE static performance, we developed and tested four configurations of modified GLARE with four variants of hooks' geometry, including two hook sizes, namely, nano and micro and two hook profiles, namely, curved and straight. Experimental results show that modified GLARE with Straight Nano Hooks (SNH) outperform all samples tested including the standard GLARE (without hooks) in shear, and three‐point bending tests. Whereas, a drop of about 4.5% and 3% is observed, respectively, in the elastic modulus and tensile yield strength of modified GLARE with SNHs, compared to standard GLARE. Microscopic inspection of the four configurations of modified GLARE also illustrates that SNHs generate modified GLARE with minimal manufacturing defects. The results obtained indicate that SNH is the optimum hook geometry for the development of modified GLARE. It can be considered as an alternative surface treatment for sheet metals in Fibre‐metal laminates development process as it offers a modified version of the material with comparable static performance to those manufactured by the industrial standard methodology but at a fraction of production cost. POLYM. COMPOS., 40:1510–1525, 2019. © 2018 Society of Plastics Engineers
Understanding the fundamental properties of epoxy molybdenum disulfide nanocomposites
Authors: Peddamallu Nagachandrika , Sridharan Krishnamurthy , Nakayama Tadachika , Sarathi Ramanujam
Published: May 2018

The surface discharge inception voltage (SDIV) of epoxy MoS2 nanocomposite is high under DC voltage compared to AC voltages. It is also observed that SDIV increases up to 0.5 wt% of MoS2 added epoxy resin and above which a marginal reduction in SDIV is observed. Surface charge accumulation is less with epoxy nanocomposite compared with epoxy resin. With increase in percentage of MoS2, complete reduction in charge retention time is observed. Surface roughness measurement with the surface discharge caused damage zone with epoxy nanocomposites indicate that surface roughness is less when the percentage of MoS2 is increased and above certain weight percentage, the surface roughness is almost same. Epoxy nanocomposites show a marginal increase in contact angle with increase in weight percentage of molybdenum disulfide. LIBS studies indicate that the crater depth and the plasma temperarure measured is low for epoxy nanocomposites with 0.5 wt% MoS2. POLYM. COMPOS., 40:1556–1563, 2019. © 2018 Society of Plastics Engineers
Toughening of bamboo fibers/unsaturated polyester composites with 2‐acetoacetoxyethyl methacrylate
Authors: Fei Ming‐En , Xie Tianshun , Liu Wendi , Qiu Renhui
Published: May 2018

Bamboo fibers (BFs)‐reinforced unsaturated polyester (UPE) composites were prepared by hand lay‐up compression molding. The UPE resins were modified with 2‐acetoacetoxyethyl methacrylate (AAEM) and designed to improve the flexibility and toughness of the BFs–UPE composites. The results indicated that the toughness of the composites significantly increased as the AAEM usage increased. When compared with the untreated UPE composites, the composites obtained from AAEM modified UPE resins (with a 20:80 weight ratio of AAEM to UPE) had 21.7% higher impact strength. Dynamic mechanical analysis showed that incorporation of AAEM significantly increased the damping parameter and decreased glass transition temperature of the composites due to the introduction of flexible segments of AAEM into the UPE resins. Scanning electron microscopy images of the impact‐fractured surfaces of the composites revealed that AAEM modification improved the interfacial adhesion between BFs and UPE matrices. The main mechanism for the increase in the toughness of the composites could be due to the increased ductility of the matrices. POLYM. COMPOS., 40:1595–1601, 2019. © 2018 Society of Plastics Engineers
New approach for fast identification of cyclitols by MALDI‐TOF mass spectrometry
Authors: Al‐Suod Hossam , Pomastowski Paweł , Ligor Magdalena , Railean‐Plugaru Viorica , Buszewski Bogusław
Published: May 2018

Introduction

Alfalfa (Medicago sativa L.) is the subject of many studies due to its numerous chemical constituents and beneficial properties. Among these constituents are cyclitols, which have attracted attention due to the variety of biological properties they have.

Objective

A rapid and sensitive analytical procedure based on matrix‐assisted laser desorption ionisation technique with time‐of‐flight and mass spectrometry (MALDI‐TOF‐MS) analysis was used for the first time for the identification of three cyclitols from different parts of alfalfa.

Methodology

Plant extracts were prepared and purified using Soxhlet extraction and solid‐phase extraction (SPE). Then, samples were dissolved in α‐cyano‐4‐hydroxycinnamic acid (HCCA) matrix, and subjected to MALDI‐TOF‐MS analysis.

Results

The ion at m/z 524.0 was distributed in all standards and in leaves and stem extracts. In turn, the signal at m/z 335.1 was found in all standards and all alfalfa extracts. The ion at m/z144.1 was found just for d‐chiro‐inositol and distributed in all extracts. Both signals at m/z 265.9 and 250.0 were found only in l‐chiro‐inositol standard and the extract of stem. However, the ion at m/z 177.1 was found in d‐pinitol standard and the extract of leaves. Based on molecular weights, information on fragment ions obtained by MALDI‐TOF‐MS, and the chemistry of cyclitols, we successfully identified three cyclitols (d‐chiro‐inositol, l‐chiro‐inositol, d‐pinitol) in different parts of alfalfa (leaves, stem, flowers).

Conclusion

The obtained results in this study proved that MALDI‐TOF‐MS is a rapid, sensitive and very powerful tool for identification of cyclitols within plants and has the potential to differentiate between enantiomers.
Microcellular silicone rubber foams: The influence of reinforcing agent on cellular morphology and nucleation
Authors: Xiang Bin , Deng Zhaoping , Zhang Fengshun , Wen Na , Lei Yajie , Liu Tao , Luo Shikai
Published: May 2018

A series of microcellular silicone rubber foams were prepared by supercritical carbon dioxide (scCO2). The effect of reinforcing agent (silica) on the rheological behavior, cellular morphology and nucleation of silicone rubber composites was investigated. The results show that the silica not only acts as reinforcing agent but also plays an important role in the cellular nucleation. When the content of silica increases from 40 phr to 70 phr, the range of the calculated surface tension of silicon rubber composites/scCO2(γmix) and radius of the critical nucleus (r*) are 158.95∼1,092.74 nN/m and 14.45–99.34 nm, respectively. Meanwhile, aggregated silica has good heterogeneous nucleation as the diameter of aggregated silica particles is approximate to twicer*. The smallest cell diameter and the highest cell density of the silicone rubber foam can reach to 708 nm and 1.02 × 1011cells/cm3, which indicate that the silicone rubber nanofoams can be obtained by means of the supercritical foaming technology. POLYM. ENG. SCI., 59:5–14, 2019. © 2018 Society of Plastics Engineers
Enhanced Near‐Infrared Shielding and Light Scattering Using Surface‐Roughened Hybrid Hollow Microparticles Synthesized with Polymer and TiO2@Al(OH)3 for Cosmetic Applications
Authors: Han Nuri , Kim Min Gyu , Kim Sung Wook , Shin Min Kyu , Kim Su Ji , Kim Moo Sung , Lee Sang Rin , Lee Jun Bae , Pyun Seung Beom , La Ju A , Song Ji Eun , Cho Eun Chul
Published: May 2018

Some materials and their micro‐/nanostructures are explored to shield near‐infrared (NIR) light. However, the structural role of polymeric matrices in terms of the sensitivity to NIR light and the scattering/absorption characteristics of particles bearing inorganic colloids lack understanding. To understand this issue further, a polymer–inorganic hybrid microparticle is synthesized, where submicrometer‐sized TiO2 core‐thin aluminium hydroxide shell colloids (TiO2@Al(OH)3) are dispersed in a roughened polymer hollow particle matrix. They exhibit higher light extinction at NIR frequencies and higher light scattering efficiencies in the NIR regions compared to hybrid solid microparticles and a simple mixture of inorganic and polymer hollow microparticles. Owing to these characteristics, a cosmetic formulation containing the roughened hybrid hollow microparticles effectively suppresses the increase in the temperatures of artificial skin upon the illumination of a simulated sunlight, without displaying skin whitening which is caused by including much inorganic colloids in the formulation. The present results are helpful to those who manipulate the optical characteristics of inorganic particles whose geometries are hardly tailored. The results are also practically helpful to those who want to block NIR light by reducing the amount of inorganic particles.
Redox‐regulated methionine oxidation of Arabidopsis thaliana glutathione transferase Phi9 induces H‐site flexibility
Authors: Tossounian Maria‐Armineh , Wahni Khadija , Van Molle Inge , Vertommen Didier , Astolfi Rosado Leonardo , Messens Joris
Published: May 2018

Glutathione transferase enzymes help plants to cope with biotic and abiotic stress. They mainly catalyze the conjugation of glutathione (GSH) onto xenobiotics, and some act as glutathione peroxidase. With X‐ray crystallography, kinetics, and thermodynamics, we studied the impact of oxidation on Arabidopsis thaliana glutathione transferase Phi 9 (GSTF9). GSTF9 has no cysteine in its sequence, and it adopts a universal GST structural fold characterized by a typical conserved GSH‐binding site (G‐site) and a hydrophobic co‐substrate‐binding site (H‐site). At elevated H2O2 concentrations, methionine sulfur oxidation decreases its transferase activity. This oxidation increases the flexibility of the H‐site loop, which is reflected in lower activities for hydrophobic substrates. Determination of the transition state thermodynamic parameters shows that upon oxidation an increased enthalpic penalty is counterbalanced by a more favorable entropic contribution. All in all, to guarantee functionality under oxidative stress conditions, GSTF9 employs a thermodynamic and structural compensatory mechanism and becomes substrate of methionine sulfoxide reductases, making it a redox‐regulated enzyme.
Transparency Engineering in Quantum Dot‐Based Memories
Authors: Arikan Ismail Firat , Cottet Nathanaël , Nowozin Tobias , Bimberg Dieter
Published: May 2018

Quantum dot (QD) based memories offer new functionalities as compared to present main stream ones by combining the advantages of DRAM (fast access and write/erase time, good endurance) and Flash memories (long storage time). The present storage times in such memories are demonstrated to be several days at room temperature for GaP‐based devices, while write times as short as picoseconds are possible. There exists however a trade‐off between storage time and erase time. To eliminate this trade‐off, resonant tunneling effects in single or double quantum well structures are studied here as a promising approach. The quantum well structures based on GaAs/Al0.9Ga0.1As and GaP/AlP quantum wells inserted in QD‐based memories are designed and simulated using a Schrödinger‐Poisson solver and non‐equilibrium Green's functions (NEGF) to calculate the transparency at a given voltage. By choosing the width of the quantum wells, precise positioning of their energy levels allows for transparency engineering. Our simulations show an increase in transparency by at least 7 orders of magnitude at resonance, leading indeed to sufficiently fast erase times, thus solving the trade‐off problem.
Transmission channels in the time‐energy uncertainty relation approach to molecular conductance: Symmetry rules for the electron transport in molecules
Authors: Ramos‐Berdullas Nicolás , Gil‐Guerrero Sara , Mandado Marcos
Published: May 2018

The concept of transmission channel plays a key role in the theory of molecular conductors. They are usually constructed from one‐electron functions (molecular spin orbitals) in the extensively employed LCAO‐MO method. Thus, the electric conductance can be obtained from the transmission matrix, whose diagonalization leads to a set of transmission eigenchannels. In this work, it is shown how using the time‐energy uncertainty relation approach, the electron transport can be also analysed in terms of coupled transmission channels. Here, the transmission channels are constructed in terms of electron deformation orbitals (EDOs), which in turn arise from linear combinations of occupied and unoccupied one‐electron functions. These transmission channels allow linking the electric conduction in molecular junctions with the traditional interpretation in mesoscopic systems, where the electron transport occurs by promotion of electrons from the valence to the conduction bands. Moreover, they lead to an expression of the electric conductance within the Landauer formalism, with the conductance given by the product of the quantum conductance and a transmission function. Transmission channels of junctions formed by polycyclic aromatic chains attached to gold atoms are analysed in detail. Symmetry rules for the MOs involved in these channels are established, giving rise to a straightforward method for the analysis of the transport ability in molecular systems.
Relevance and relational responsibility in justice‐oriented science education research
Authors: Tolbert Sara , Schindel Alexa , Rodriguez Alberto J.
Published: May 2018

In this article, we critically examine what a commitment to equity, diversity, and social justice in science and science education means for our research practices and methods. Using a blend of critical cross‐cultural and feminist lenses, we explore relationships of power in our research, specifically in terms of knowledge production, representation, and positionality. We also consider our ethical obligations and relational responsibilities as researchers in terms of caring and solidarity. We argue that relevance should be measured as a function of the transformative impact of the research enterprise. We also argue that to do this, researchers need to examine and expose their own positioning and positionality. We propose a variety of strategies, drawn from our work and from that of many others, which illustrate how to build and sustain more caring, ethical, responsive, and responsible relationships with research participants.
Aminomethylanthracene Dyes as High‐Ionic‐Strength DNA‐Photocleaving Agents: Two Rings are Better than One
Authors: Safiarian Mohammad S. , Sawoo Sudeshna , Mapp Carla T. , Williams Dominique E. , Gude Lourdes , Fernández María‐José , Lorente Antonio , Grant Kathryn B.
Published: May 2018

This paper compares the DNA interactions of a bis 9‐aminomethylanthracene dye (2) vs. a mono‐anthracene (4) under high ionic strength conditions similar to those in the cell nucleus (∼150 mM NaCl and 260 mM KCl). The chloride salts triggered an enhancement in anthracene‐sensitized DNA photocleavage, where bis‐anthracene 2 exhibited superior DNA binding affinity, faster reaction kinetics, and higher levels of DNA damage at low‐ to sub‐micro molar dye concentrations (350 nm hν, pH 7.0). While spectroscopic and viscometric data suggested that the chloride salts reduced DNA intercalation in favor of a non‐intercalative binding mode in which 2 and 4 were better able to generate hydroxyl radicals, there was evidence of persistent intercalation of the second anthracene ring of 2. We propose that such an interaction anchored the bis‐anthracene to DNA under the high ionic strength conditions, increasing its binding affinity and photocleaving capabilities relative to the mono analog (4).
Shy Organic Photovoltaics: Digitally Printed Organic Solar Modules With Hidden Interconnects
Authors: Maisch Philipp , Tam Kai Cheong , Schilinsky Pavel , Egelhaaf Hans‐Joachim , Brabec Christoph J.
Published: May 2018

One of the biggest attractions of the organic photovoltaics (OPV) technology is the easiness with which it can be integrated. However, despite its semitransparency and wide variety of colors, a major unresolved challenge is to fabricate optically inconspicuous organic photovoltaic modules (OPV‐M) that can be integrated into visually demanding products. This is dominantly due to the visual obstruction from Z‐interconnection lines inherent to module processing with classical patterning methods. We now present for the first time a solution to this problem, which utilizes a visually seamless interconnection method to elegantly minimize the conspicuity of the interconnection regime. We realize such invisible interconnects by inkjet printing highly conductive silver lines, which penetrate the solar cell stack and form an electrical connection between adjacent cells. A combined characterization approach utilizing in‐depth electrical characterization and finite element (FEM) simulation rationalizes the excellent electrical cell‐to‐cell contact established with this interconnection technology. We combine this technology with a variable‐geometry module design into an innovative digital inkjet printing platform for the production of state‐of‐the art but visually attractive solar modules. The full potential of this concept is demonstrated by a fully inkjet printed arbitrarily shaped OPV‐M portrait.
Synthesis of High‐Quality Wurtzite Cu2ZnSn(S1−x,Sex)4 Nanocrystals With Non‐Toxic Selenium Precursor and the Photoelectrochemical Performance of ZnO NAs/CZTSSe Heterojunction
Authors: Gao Yao , Wang Jilin , Mo Shuyi , Wang Fuwen , Long Fei , Zou Zhengguang
Published: May 2018

Fabrication of high performing CZTSSe absorber material from environmental benign nanocrystals ink is very important for large‐scale manufacturing production. Herein, the high‐quality metastable wurtzite Cu2ZnSnS4 (W‐CZTS) and wurtzite Cu2ZnSn(S1−x,Sex)4 (W‐CZTSSe) nanocrystals with small sizes have been synthesized successfully using dodecanethiol (DDT) and Se‐octadecylamine (Se‐ODA) as the sulfur and selenium sources, respectively. Compared to the thin film obtained from W‐CZTS nanocrystals ink, the thickness of small grain layer in the thin film obtained from W‐CZTSSe nanocrystals is reduced significantly. Further the ZnO nanoarrays (NAs)/CZTSSe heterojunction thin‐film grows on fluorine‐doped tin oxide (FTO) substrate and it exhibits superior photoelectrochemical (PEC) performance under light illumination. The ZnO NAs/CZTSSe heterojunction thin film shows the photocurrent density of 3.44 mA cm−2, which is nearly 2.7‐fold higher than the photocurrent density of ZnO NAs. The PEC efficiencies of ZnO NAs and ZnO NAs/CZTSSe are 0.4% and 1.89%, respectively. Our results demonstrate that the as‐synthesized W‐CZTSSe nanocrystals by using Se‐ODA are a promising precursor to fabricate high performing thin film, the Se‐ODA can be applied to prepare the precursors of chalcogenide thin film (including CISe, CIGSe, and CZTSSe).
Laser Desorption/Ionization Mass Spectrometry of Perovskite Solar Cells: Identification of Interface Interactions and Degradation Reactions
Authors: Sultana Nishat , Demarais Nicholas J. , Shevchenko Denys , Derrick Peter J.
Published: May 2018

It is demonstrated that laser desorption/ionization mass spectrometry (LDI‐MS) is a promising technique for the study of molecular interactions as well as the direct identification of degradation products from perovskite solar cells (PSCs) without the necessity to dissolve the device, remove the metal cathode, or add an external matrix. The chemical stability of the individual layers and starting materials are assessed and compared to full device structures. Mechanisms for degradation products, interfacial interactions, and intra‐device reactions are proposed. Reactive oxygen species quickly degrade the perovskite layer to form lead oxyiodide and iodine. The iodine released from this process or other perovskite degradation products like HI and CH3NH3I undergo further reactions with the other layers within 1 day and are detected as and . Alternatively, the interfacial interaction between the perovskite and spiro‐OMeTAD layer to form a charge‐transfer complex appears to increase over time, which may enhance device efficiency.
Planung und Fertigung des Starttisches und des Versorgungsmastes für die Ariane 6
Authors: Nicolay Thorsten , Kühnemund Frank , Moses Frank , Brössel Holger
Published: May 2018

Herrn Prof. Dr.‐Ing Jörg Lange zur Vollendung seines 60. Lebensjahres gewidmet

Für die neue europäische Trägerrakete Ariane 6 wird auf dem Weltraumbahnhof Kourou in Französisch‐Guyana eine neue Startanlage gebaut. Zentrale Bauwerke der Startanlage werden der Starttisch und der Versorgungsmast für die Rakete sein. Der Starttisch dient als Plattform für die Rakete, muss die Belastung aus dem Start abtragen und beinhaltet umfangreiche technische Ausstattung. Der Mast ist bis zum Start für die Versorgung der Rakete verantwortlich und ebenfalls mit umfangreichen Überwachungsgeräten ausgestattet. Beide Bauwerke sind komplexe Stahlkonstruktionen. Nachfolgend wird auf die Planung sowie die Fertigung dieser beiden Konstruktionen eingegangen und die einzelnen Bauteile werden detailliert beschrieben.
Zum Stabilitätsnachweis von Stahlbauteilen aus einfach‐ und doppeltsymmetrischen I‐Querschnitten unter Biegung, Druck und Torsion
Authors: Winkler Rebekka , Walter Adrian , Knobloch Markus
Published: May 2018

Herrn Prof. Dr.‐Ing. Jörg Lange zur Vollendung seines 60. Lebensjahres gewidmet

Das vereinfachte Nachweisverfahren mit Abminderungsfaktoren wird für die Bemessung von Stahlbauteilen trotz zunehmender Computerunterstützung und Verwendung numerischer Verfahren weiterhin angewendet. Die Interaktionsgleichungen der EN 1993‐1‐1 gelten für Bauteile mit doppeltsymmetrischen I‐ und H‐Querschnitten sowie Hohlprofilen und schließen den Fall der planmäßigen Torsion bisher aus. Eine Erweiterung des Nachweisverfahrens auf einfachsymmetrische Querschnitte und planmäßige Torsion wird gegenwärtig im Rahmen der Überarbeitung und Weiterentwicklung des Eurocodes 3 evaluiert. Der vorliegende Beitrag berichtet über numerische Simulationen zum Tragverhalten einfach‐ und doppeltsymmetrischer I‐/H‐Querschnitte unter Druck, Biegung und Torsion sowie die Ableitung eines vereinfachten Nachweisverfahrens mit Abminderungsfaktoren und dessen Hintergründe. Er leistet somit einen Beitrag zur aktuellen Diskussion.
Jörg Lange – Vorbild und Vorreiter für Studium und Lehre
Authors: Merle Heiko , Rädel Felicitas
Published: May 2018

Herrn Prof. Dr.‐Ing. Jörg Lange zur Vollendung seines 60. Lebensjahres gewidmet
“A Give Grief Kind of Guy”: Help‐Seeking, Status, and the Experience of Helpers at a University IT Help Desk
Authors: Seeley J. Lotus
Published: May 2018

Returning the helper to studies of help‐seeking highlights how organizational status is interactionally (re)produced. Using interview and ethnographic data of IT support workers in a medical school, I illuminate how organizational status hierarchies develop independently of organizational rank or authority. Status both structures and is (re)produced through requestors' enactment of deference and/or face‐threatening acts; backstage interpretive processes among helpers naturalize and legitimate status‐based interaction styles. High‐status requestors' failure to protect helpers' face does not flow naturally from organizational status but is the result of active meaning‐making processes with meso‐level implications.
Multinational companies and human resource management in Ireland during recession: A retrospective from a highly globalized economy
Authors: Gunnigle Patrick , Lavelle Jonathan , Monaghan Sinéad
Published: May 2018

This article provides a retrospective investigation of the impact of the recent “great recession” on human resource management (HRM) in multinational companies (MNCs) in Ireland. Ireland represents a particularly fitting location within which to address this topic given its standing as one of the world's most economically globalized and MNC‐dependent economies and also because the country was very severely impacted by the global financial crisis. Using both primary and secondary data from a variety of sources, our analysis considers the impact of recession on HRM in MNCs, with particular focus on employment, pay and benefits, industrial relations, and the role of the human resource (HR) function. The findings suggest that HR practitioners played a central role in implementing a series of initiatives, many of which were operational in nature, to improve business performance. In so doing, we argue that practitioners in MNCs in Ireland behaved as archetypical “conformist innovators” during the recent recession, delivering operational HR responses to improve their organization's bottom line.
A preliminary assessment of microstructural and compositional characteristics of two variants of precarbonated and postcarbonated concrete mixes
Authors: Verma Shwetambara , Sengupta Somesh , Varadharajan Srinivasan , Kumar Arun
Published: May 2018

The hydration, precarbonation, and postcarbonation microstructural and compositional attributes of 2 variants of concrete were studied using scanning electron microscope, energy dispersive spectroscopy, and X‐ray diffraction techniques. Results obtained showed presence of large number of diffraction peaks indicative of SiO2 as major phase. Higher pH, alkalinity, and absence of effects of carbonation were suggested from the presence of portlandite peaks. Evidence of effect of carbonation was studied through the analysis of the experimental diffraction peaks obtained postexposure to accelerated carbonation in a controlled environment. Presence of all the 3 polymorphs of calcium carbonate (CaCO3) such as aragonite, vaterite, and calcite depending upon the moisture content and the material constituting the concrete sample were envisaged signifying carbonation. Precipitation of these CaCO3 crystals was responsible for depletion of CH as well as calcium–silicate–hydrate, ettringite with the progress of carbonation as suggested by their absence in the X‐ray diffraction diffractograms of the carbonated samples. The crystal structure of the newly formed minerals in both the variants of concrete sample was highly controlled by the stages of carbonation, with development of amorphous CaCO3 (amalgamated with that of calcium hydrates) in early stages of carbonation as well as fully developed rhombohedral CaCO3 crystals in later stages.
N‐shell ionization cross sections by proton impact in the BEA
Authors: Mukoyama Takeshi
Published: May 2018

The N‐subshell ionizations cross sections of heavy elements by proton impact have been calculated in the binary‐encounter approximation. The momentum distribution of target electrons is taken into account by the use of the nonrelativistic and relativistic hydrogenic models and the Hartree–Fock–Roothaan and the relativistic Hartree–Fock–Roothaan methods. The obtained subshell ionization cross sections are compared with the experimental data and other theoretical calculations. The electronic relativistic effect and the wave‐function effect on N‐shell ionization cross sections are discussed.