Topological Crystalline Insulator Nanomembrane with Strain-Tunable Band Gap

The ability to fine-tune band gap and band inversion in topological materials is highly desirable for the development of novel functional devices. Here we propose that the electronic properties of a free-standing nanomembrane of topological crystalline insulator (TCI) SnTe and Pb$_{1-x}$Sn$_x$(Se,Te) are highly tunable by engineering elastic strain and controlling membrane thickness, resulting in tunable band gap and giant piezoconductivity. Membrane thickness governs the hybridization of topological electronic states on opposite surfaces, while elastic strain can further modulate the hybridization strength by controlling the penetration length of surface states. We propose a frequency-resolved infrared photodetector using force-concentration induced inhomogeneous elastic strain in TCI nanomembrane with spatially varying width. The predicted tunable band gap accompanied by strong spin-textured electronic states will open up new avenues for fabricating piezoresistive devices, thermoelectrics, infrared detectors and energy-efficient electronic and optoelectronic devices based on TCI nanomembrane.Comment: 10 pages, 9 figure

Near Neutrality of an Oxygen Molecule Adsorbed on a Pt(111) Surface

The charge state of paramagnetic or nonmagnetic O2 adsorbed on a Pt(111) surface is analyzed using density functional theory. We find no significant charge transfer between Pt and the two adsorbed molecular precursors, suggesting these oxygen reduction reaction (ORR) intermediates are nearly neutral, and changes in magnetic moment come from self adjustment of O2 spin-orbital occupations. Our findings support a greatly simplified model of electrocatalyzed ORR, and also point to more subtle pictures of adsorbates or impurities interacting with crystal than literal integer charge transfers

Significant Improvement in TiO₂ Photocatalytic Activity through Controllable ZrO₂ Deposition

ZrO2 was deposited on anatase TiO2 nanoparticles using 5-80 cycles of atomic layer deposition (ALD). The photocatalytic activity of all samples was evaluated based on the degradation of methylene blue (MB) solution under UV light. The TiO2 sample with 45 cycles of ZrO2 deposition (45c-Zr/TiO2, 1.1 wt% ZrO2) was proved to be the most efficient catalyst with a degradation kinetic constant 10 times larger than that of the pure TiO2 sample. All samples were characterized using inductively coupled plasma atomic emission spectroscopy (ICP-AES), nitrogen adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra analysis (UV-DRS), Raman and photoluminescence (PL) techniques. The high photocatalytic activity of 45c-Zr/TiO2 can be attributed to stronger adsorption in the ultraviolet region and a reduction in the recombination rate of electron/hole pairs

Investigating the feasibility of supply chain-centric business models in 3D chocolate printing: a simulation study

This is the author accepted manuscript. The final version is available from Science Direct via the DOI in this record.3D chocolate printing provides the technology for manufacturing chocolates layer-by-layer, thus offering customers enhanced product value and personalized consumption experience. As business models in the chocolate industry are closely associated with the profitability of the supply chain constituents, it seems appropriate to investigate the financial viability of these supply-chain centric business models prior to their introduction in the real world. In this paper we present two business models pertaining to the supply chain for 3D printed chocolates; we evaluate the financial viability of these innovative models through the use of computer modelling and simulation. The study is based on the commercialization efforts of a UK based 3D chocolate printing technology provider (Choc Edge). The results of the study indicate that 1) the retailer dominant supply chain model is a potentially disruptive business model innovations that are enabled by the 3D food printing technology, and as such, may pose a challenge to traditional high end chocolate products; 2) the manufacturer dominant model helps manufacturers gain more profits while retailer profits tend to be stagnant.We would like to thank the financial support of Chartered Institute of Logistics and Transport (CILT) and the Bridging the gap of EPSRC in the UK and Humanities and Social Sciences Foundation of Ministry of Education in China (Grant number: 14YJC630130)

FAM222A encodes a protein which accumulates in plaques in Alzheimer's disease.

Alzheimer's disease (AD) is characterized by amyloid plaques and progressive cerebral atrophy. Here, we report FAM222A as a putative brain atrophy susceptibility gene. Our cross-phenotype association analysis of imaging genetics indicates a potential link between FAM222A and AD-related regional brain atrophy. The protein encoded by FAM222A is predominantly expressed in the CNS and is increased in brains of patients with AD and in an AD mouse model. It accumulates within amyloid deposits, physically interacts with amyloid-β (Aβ) via its N-terminal Aβ binding domain, and facilitates Aβ aggregation. Intracerebroventricular infusion or forced expression of this protein exacerbates neuroinflammation and cognitive dysfunction in an AD mouse model whereas ablation of this protein suppresses the formation of amyloid deposits, neuroinflammation and cognitive deficits in the AD mouse model. Our data support the pathological relevance of protein encoded by FAM222A in AD

Crustal and mantle velocity models of southern Tibet from finite frequency tomography

Using traveltimes of teleseismic body waves recorded by several temporary local seismic arrays, we carried out finite‐frequency tomographic inversions to image the three‐dimensional velocity structure beneath southern Tibet to examine the roles of the upper mantle in the formation of the Tibetan Plateau. The results reveal a region of relatively high P and S wave velocity anomalies extending from the uppermost mantle to at least 200 km depth beneath the Higher Himalaya. We interpret this high‐velocity anomaly as the underthrusting Indian mantle lithosphere. There is a strong low P and S wave velocity anomaly that extends from the lower crust to at least 200 km depth beneath the Yadong‐Gulu rift, suggesting that rifting in southern Tibet is probably a process that involves the entire lithosphere. Intermediate‐depth earthquakes in southern Tibet are located at the top of an anomalous feature in the mantle with a low Vp, a high Vs, and a low Vp/Vs ratio. One possible explanation for this unusual velocity anomaly is the ongoing granulite‐eclogite transformation. Together with the compressional stress from the collision, eclogitization and the associated negative buoyancy force offer a plausible mechanism that causes the subduction of the Indian mantle lithosphere beneath the Higher Himalaya. Our tomographic model and the observation of north‐dipping lineations in the upper mantle suggest that the Indian mantle lithosphere has been broken laterally in the direction perpendicular to the convergence beneath the north‐south trending rifts and subducted in a progressive, piecewise and subparallel fashion with the current one beneath the Higher Himalaya

DESIGNING SPEECH INTERFACE APPLICATIONS FOR ACQUISITION OF AGRICULTURAL INFORMATION

It will be argued that customary software design strategies, by themselves, fall short when designing speech recognition applications. Concepts of experimental design and analysis are also necessary for developing speech interface software. This study demonstrates that these tools can be advantageous to the software developer, especially if the prototype methodology model of software development is applied. A case study for the problem of developing a speech interface for collecting, or mapping, information on cotton plant growth is presented. The acquisition of cotton plant map data is a \u27hands and eyes\u27 busy task that requires considerable investment to record and convert hand-written data sheets into computer data files. The project goal is to develop software that converts spoken key words and phrases describing a cotton plant into text \u27strings\u27 that are subsequently manipulated into a computer ready data file

Regulating effect of β-ketoacyl synthase domain of fatty acid synthase on fatty acyl chain length in de novo fatty acid synthesis

Fatty acid synthase (FAS) is a multifunctional homodimeric protein, and is the key enzyme required for the anabolic conversion of dietary carbohydrates to fatty acids. FAS synthesizes long-chain fatty acids from three substrates: acetyl-CoA as a primer, malonyl-CoA as a 2 carbon donor, and NADPH for reduction. The entire reaction is composed of numerous sequential steps, each catalyzed by a specific functional domain of the enzyme. FAS comprises seven different functional domains, among which the β-ketoacyl synthase (KS) domain carries out the key condensation reaction to elongate the length of fatty acid chain. Acyl tail length controlled fatty acid synthesis in eukaryotes is a classic example of how a chain building multienzyme works. Different hypotheses have been put forward to explain how those sub-units of FAS are orchestrated to produce fatty acids with proper molecular weight. In the present study, molecular dynamics simulation based binding free energy calculation and access tunnels analysis showed that the C16 acyl tail fatty acid, the major product of FAS, fits to the active site on KS domain better than any other substrates. These simulations supported a new hypothesis about the mechanism of fatty acid production ratio: the geometric shape of active site on KS domain might play a determinate role