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Abstract: Choline acetyltransferase (ChAT, acetylCoA:choline O-acetyltransferase, EC 2.3.1.6) is the biosynthetic enzyme of neurotransmitter acetylcholine. Here we showed for the first time that transgenic mice with human ChAT kept excellent learning and memory ability during aging process. Transgenic mice were prepared through microinjection of human ChAT into mouse fertilized eggs, and PCR reaction was used to screen out the transgenic mice. The results of measurements of ChAT activity and acetylcholine level in mouse brain indicated that human ChAT gene was expressed throughout the life of the transgenic mice. The results of step-through test and water maze test suggested that learning and memory ability was improved in transgenic mice compared to that of their age-matched littermates. The results support our idea that supplement of ChAT might serve as a potential therapeutic strategy for cognitive deficit. [Copyright &y& Elsevier]

Abstract: We examined if the relative expression of JNK-interacting protein 1 (JIP1) and phosphorylated c-Jun N-terminal kinase (JNK) regulates cell signaling and contributes to selective neuronal vulnerability in response to environmental stress. In clonal neuroblastoma cultures, stresses such as hypoxia, ischemia, Aβ peptides, and UV irradiation rapidly reduced JIP1 expression. JIP1 mRNA expression was also down-regulated by UV stress and was accompanied by increased JNK and c-Jun activation and cell death. JIP1 protein reduction was partially reversed both by inhibitors predominantly of caspase 3 and of the JNK pathway and resulted in significantly increased cell survival. Conversely, overexpression of JIP1 decreased both nuclear translocation of activated-JNK, and c-Jun phosphorylation induced by either UV irradiation, or the JNK upstream activators, MKK7 or MEKK1. Cell death was reduced about 50% compared to GFP-transfected controls. JIP1 overexpression did not facilitate either JNK expression or activation. In the normal, non-stressed human hippocampus and rat hippocampal organotypic cultures, JIP1 and JNK3 were inversely expressed with more JIP1 in CA2 and CA3 and less in CA1 neurons. In the human hippocampus, transient hypoxia/ischemia selectively spares neurons in CA2 and CA3 and induces death of neurons in the hippocampal CA1 subregion. In the cultures, ischemia reduced JIP1 expression and activated JNK, c-Jun, and caspase 3. Inhibitors of the JNK pathway, JNK activation directly and of caspase 3 activation each partially reversed these effects. Thus, under certain stress conditions, down-regulation of JIP1 expression makes neurons more susceptible to apoptosis, suggesting JIP may serve as an anti-apoptosis factor. [Copyright &y& Elsevier]

Metallic glasses (MGs) have unusual structural characteristics and resulting unique properties, but effectively modulating their structure is difficult. The recently achieved two-way structural tuning (ordering-disordering) between distinct states in MGs offers an opportunity to overcome this challenge. However, pressures up to tens of GPa were required for the process, which limits sample sizes at the micrometer scale and challenges further comprehensive research. Here, by introducing concurrent shear straining with compressive force using high-pressure torsion, the pressure to trigger the disordering transition is significantly reduced to a few GPa. This enables the acquisition of millimeter-sized samples for comprehensive study, including synchrotron x-ray diffraction and small angle x-ray scatting, nanoindentation, electrical resistivity, and differential scanning calorimetry. It is evidenced that the two-way tuning of MG can be achieved both structurally and thermodynamically, which could help deepen our understanding of the mechanism behind the two-way tuning and promote exploration of distinct MGs. [Display omitted] [ABSTRACT FROM AUTHOR]

AlH3 is a promising hydrogen storage material due to its high hydrogen capacity (10 wt%) and relatively low dehydriding temperature. In this work, γ-AlH3 was prepared by organometallic synthesis method and the effects of ball milling on dehydriding properties of γ-AlH3 were investigated systematically. Experimental results shows that as-prepared γ-AlH3 releases about 8.3 wt% of hydrogen in the temperature range of 130–160 °C at a heating rate of 2 °C/min. Ball milling significantly improves the dehydriding behavior of γ-AlH3. DSC-MS analysis reveals that the dehydriding temperature of γ-AlH3 ball-milled for 10 h decreases by around 30 °C. In addition, the dehydriding activation energy of γ-AlH3 ball-milled for 2 h decreased from 87 to 68 kJ/mol. Isothermal dehydriding measurements demonstrate that duration needed to release 90% hydrogen for as-prepared γ-AlH3 is 280 min, but it takes only 82 min after ball milled for 10 h to release the same amount of hydrogen. Moreover, the dehydriding path of γ-AlH3 is changed by ball milling. As-prepared γ-AlH3 transforms to α-AlH3 before dehydriding, while ball-milled γ-AlH3 prefers to dehydride directly without firstly transforming to α-AlH3. [ABSTRACT FROM AUTHOR]

A simple method of improving hydrogen generation from the reaction between highly activated Mg powder and water is established. The Mg–H2O reaction is found to become faster and more intense when magnesium is mixed with salts and subjected to by high-energy ball milling. Among the studied salts, AlCl3 has the best performance. The milling time and salt content significantly affect the final hydrogen yield and reaction kinetics. Among all studied samples, 6 h-milled Mg–3 mol% AlCl3 shows the best performance with a hydrogen yield of 93.86% and IHGR (initial hydrogen generation rate) of 455.9 ml min−1·(g Mg)−1 within 1 h. The initial temperature is also found to have a remarkable influence on the hydrolysis of the Mg–AlCl3 mixture, and the reaction can proceed to 100% conversion in 1 min with an IHGR of 933.3 ml min−1·(g Mg)−1 at 80 °C. [ABSTRACT FROM AUTHOR]

Hypoxic stress induces apoptosis of hippocampal CA1 neurons while selectively sparing those in CA2–3. Proliferation and differentiation of local stem cells may potentially replace lost neurons. We examined MAP kinase signaling regulation of these dual responses. Rat organotypic hippocampal cultures were exposed to hypoxia for up to 6 h followed by reoxygenation. JNKs and ERKs were maximally activated by 4 h, returning approximately to basal levels by 6 h. Apoptosis of CA1 neurons was maximal by 6-h hypoxia, although JNK activation had returned to basal levels. A neuroprotective protein, JNK-interacting protein 1 (JIP1), an inhibitor of JNK-mediated apoptosis, was reduced by 6-h hypoxia and markedly decreased by 24-h reoxygenation in CA1 neurons as was DENN/MADD, which also modulates JNK-mediated cell death. A second peak of ERK1 activation occurred at 24-h reoxygenation and declined to control levels by 48 h. Stem cells were detected by antinestin and cell proliferation confirmed with anti-PCNA immunohistochemistry and BrdU incorporation. With U0126, an inhibitor of ERK activation, BrdU labeling was strikingly reduced implicating ERKs in the proliferation response. Antidoublecortin (DCX), which detects neural progenitor cells, colabeled a subset of BrdU-positive cells that extended from the dentate granule neurons into CA1. Astrocytes were colabeled with BrdU. Thus, hypoxia concurrently triggered both JNK and ERK signaling, and with reoxygenation, ERK1 activation and stem cell proliferation followed by neuronal progenitor cell differentiation and targeted migration to the site of pyramidal neuronal loss. [Copyright &y& Elsevier]

• CsPbBr 3 nanocrystals with EuBr 2 addition exhibit dual-band luminescence. • EuBr 2 induces phase transformation from CsPbBr 3 to Cs 4 PbBr 6. • The blue emission is originated from Eu3+-modified perovskite crystal surface. • EuBr 2 -solvent interaction influences perovskite crystallization process. Caesium lead bromide perovskite nanocrystals (PNCs) are synthesized using a room-temperature sonochemical method. By mixing equimolar of CsBr and PbBr 2 in Dimethylformamide (DMF), PNCs of CsPbBr 3 structure are formed. Under an identical reaction condition, when EuBr 2 is introduced with the CsBr/PbBr 2 precursor, the resulted product (Eu-PNCs) becomes zero-dimensional Cs 4 PbBr 6 nanocrystals. In addition to the typical green emission observed in both CsPbBr 3 and Cs 4 PbBr 6 , Eu-PNCs has a blue emission band. The overall photoluminescence quantum yield is much higher than the pristine PNCs. We perform detailed analysis of the crystal structure and luminescence properties of the nanocrystals with and without EuBr 2 modification. An X-ray absorption fine structure analysis reveals the local structure of Eu in the PNCs. We propose that the cation-solvent interaction strongly influences the crystallization process of ternary Cs x Pb y Br z , and the formation of Eu-solvent complexes further modifies the PNCs surface resulting in unique luminescence properties. [ABSTRACT FROM AUTHOR]

We present a study on the crystal structure and luminescence of Eu3+-doped calcium phosphate (Eu-CaP) nanoparticles. The sintering treatment on the pristine Eu-CaP leads to its crystallization into hydroxyapatite (HA) and further to biphasic structure that contains both HA and β-tricalcium phosphate (β-TCP). Photoluminescence spectroscopy has been a widely used technique to identify the site occupancy of Eu3+ and its thermal-induced migration behavior in pure phase CaP. However, for sintering process that involves the emergence of a second phase or the doped CaP is not luminescent, PL alone is insufficient to characterize how the dopant ions behave during the formation of a biphasic structure. In this work, we utilize X-ray absorption fine structure (XAFS) as an alternative structure probe, targeting the local structure around Eu3+, and track the change in the interatomic distance and coordination number of Eu with its neighboring O, P, and Ca atoms. A model describing formation process of a biphasic structure from HA with the presence of Eu3+ is proposed. [ABSTRACT FROM AUTHOR]

• Introduce a robust traveling salesman problem with multiple drones, which is formulated as a second-order cone program. • Reveal that robust (near-)optimal solutions can offer a large reduction of synchronization risk at a small price of makespan increase. • Develop an empirical approach to determine the ideal number of drones deployed on a truck under uncertainty. The improved unmanned aerial vehicle (UAV, or drone) delivery systems allow an unattended truck to pair two or more drones to accelerate delivery. Although such systems have been addressed in the literature, the extent to which approach can design a robust truck-drone schedule under uncertainty is not yet understood. This paper introduces a robust traveling salesman problem with multiple drones (RTSP-mD), in which a truck coordinates with a heterogeneous fleet of drones to make deliveries under uncertain navigation environments. The RTSP-mD is first formulated as a second-order cone programming (SOCP) to minimize makespan and synchronization risk simultaneously. To solve this complex problem, a three-phased adaptive large neighborhood search (ALNS) algorithm is proposed. The experiment results show that nominal optimal solution generally has a lower expected makespan but rarely remains efficient or feasible under a small perturbation to schedules. About one-third of robust optimal solutions can be against a large reduction of synchronization risk at a negligible price in makespan. And we demonstrate that the drone number remains stable for robust (near-)optimal solutions rather than growing along with customer density increase. [ABSTRACT FROM AUTHOR]

Sputtered W/B 4 C multilayers were determined by X-ray photoelectron spectroscopy, Raman scattering spectroscopy, scanning electron microscopy and atomic force microscopy synthetically. Two defect modes were observed in multilayers: buckle delamination and oxidation. This paper compares the chemical composition varies along multilayer depth and at different regions and tries to interpret the mechanism of defect evolution. The X-ray grazing incidence reflection profiles were compared to the theoretical value to estimate the influences from different defects. [ABSTRACT FROM AUTHOR]

Hydrogen generation from ball milled Al–LiH-salts mixture is studied. Different salts are used to test their effects on the hydrolysis properties of Al–LiH composite. KCl is found to be more effective than other salts and shows the best performance. Raising initial reaction temperature can effectively improve hydrogen yield and HG (hydrogen generation) rate of the Al–LiH–KCl mixture. Optimizing the milling conditions is necessary to improve the hydrogen generation performances of the composites. The addition amounts of KCl and LiH are varied and 10 mol% proves to be the optimum value for both of them in this work. Too much addition of LiH or KCl will cause the decrease of the hydrogen yield. A proper milling time of 10 h is discovered in this work which is beneficial for the decrease of grain size and improvement of reactivity. The 10 h milled Al-10 mol%LiH-10 mol% KCl mixture reaches a hydrogen yield of 97.1% in 10 min at 60 °C. Preliminary mechanism for the improvement has been discussed. [ABSTRACT FROM AUTHOR]

A novel Al based hydrogen production material is prepared by high energy ball milling using Al, CaH 2 and different salts as the starting materials. The parameters affecting the Al–H 2 O reaction are investigated and discussed. Among the salts added, NiCl 2 shows the best activation capability. The addition amount of both CaH 2 and NiCl 2 is found to be an important factor affecting the hydrolysis process during which a kind of hydrocalumite, Ca 2 Al(OH) 6 Cl(H 2 O) 2 , is generated and facilitates the removal of the by-product layer. Milling time can also generate significant impacts on the hydrogen generation performances of the mixture and 3 h proves to be the optimum choice in this work. The 3 h milled Al-10 mol% CaH 2 -10 mol% NiCl 2 sample shows a hydrogen yield of 92.1% and mHGR (maximum hydrogen generation rate) of 1566.3 ml min −1 g −1 . A preliminary study is carried out to understand the optimization mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: On-site on-demand hydrogen generation from a new Mg–LiBH4–AlCl3 system has been established. The hydrogen yield, mHGR (maximum hydrogen generation rate) and reaction stability can be adjusted by changing the samples' compositions, milling time and water/mixture ratios. The Mg-9 wt.%LiBH4-1 wt.%AlCl3 composite reaches a conversion yield of 87%, corresponding to 1083.5 ml H2 g−1 (composite), and the mHGR is 1256.9 ml min−1 g−1 in 60 min at 298 K. The synergistic effect between Mg and LiBH4 as well as the catalytic effects of LiBH4–AlCl3 additives both contribute to the improved hydrolytic performances. Compared with the hydrolysis of single Mg or Mg–LiBH4 system, the Mg–LiBH4–AlCl3 mixture has greatly improved its hydrogen yield and mHGR. This mixture is promising for its application as portable hydrogen sources. [Copyright &y& Elsevier]

• The zero-stiffness flexure hinge based on spring four-bar linkage is designed. • The rectangular leaf spring string is constructed for the spring four-bar linkage. • The range of negative stiffness of the spring four-bar linkage is determined. • The zero-stiffness quality of the zero-stiffness flexure hinge is analyzed in detail. • Samples of the zero-stiffness flexure hinge are made and tested. In order to overcome the spring back behavior of the conventional flexure hinge, the positive and negative stiffness matching method is used. The spring four-bar linkage(4BSL) is designed as a negative stiffness rotation mechanism, while the inner and outer ring of the flexure hinge (IORFH) is used as a positive stiffness mechanism. By coupling the 4BSL and the IORFH, a novel Zero-stiffness Flexure Hinge(ZSFH) is constructed. The negative stiffness characteristics of the 4BSL are analyzed and the spring of 4BSL is designed as linear rectangular leaf spring string. The zero-stiffness quality of the ZSFH based on 4BSL (ZSFH_4BSL) is analyzed, and the influence of structural parameters of the ZSFH_4BSL on zero-stiffness quality is explored. Samples are made and verified by experiments. The test results show that in the range of ±20°, the torque is reduced by 95% compared with the IORFH, and the relative error between the test result and the theoretical result is less than 7%, which verifies the validity of the theoretical analysis and the excellence of the design scheme. [ABSTRACT FROM AUTHOR]