Chiral Phonons in Chiral Materials

The concept of chirality makes ubiquitous appearance in nature. Particularly, both a structure and its collective excitations may acquire well defined chiralities. In this work, we reveal an intrinsic connection between the chiralities of a crystal structure and its phonon excitations. We show that the phonon chirality and its propagation direction are strongly coupled with the lattice chirality, which will be reversed when a chiral lattice is switched to its enantiomorph. In addition, distinct from achiral lattices, propagating chiral phonons exist for chiral crystals also on the principal axis through the $\Gamma$ point, which strengthens its relevance to various physical processes. We demonstrate our theory with a 1D helix-chain model and with a concrete and important 3D material, the $\alpha$-quartz. We predict a chirality diode effect in these systems, namely, at certain frequency window, a chiral signal can only pass the system in one way but not the other, specified by the system chirality. Experimental setups to test our theory are proposed. Our work discovers fundamental physics of chirality coupling between different levels of a system, and the predicted effects will provide a new way to control thermal transport and design information devices.Comment: 5 pages, 5 figure

Whole Brain Mapping of Long-Range Direct Input to Glutamatergic and GABAergic Neurons in Motor Cortex

Long-range neuronal circuits play an important role in motor and sensory information processing. Determining direct synaptic inputs of excited and inhibited neurons is important for understanding the circuit mechanisms involved in regulating movement. Here, we used the monosynaptic rabies tracing technique, combined with fluorescent micro-optical sectional tomography, to characterize the brain-wide input to the motor cortex (MC). The whole brain dataset showed that the main excited and inhibited neurons in the MC received inputs from similar brain regions with a quantitative difference. With 3D reconstruction we found that the distribution of input neurons, that target the primary and secondary MC, had different patterns. In the cortex, the neurons projecting to the primary MC mainly distributed in the lateral and anterior portion, while those to the secondary MC distributed in the medial and posterior portion. The input neurons in the subcortical areas also showed the topographic shift model, as in the thalamus, the neurons distributed as outer and inner shells while the neurons in the claustrum and amygdala were in the ventral and dorsal part, respectively. These results lay the anatomical foundation to understanding the organized pattern of motor circuits and the functional differences between the primary and secondary MC

Multi-functional hybrid protonated titanate nanobelts with tunable wettability

We present the preparation of millimetre-sized liquid marbles with strong mechanical strength and good deformability using self-assembled fluoroalkylsilane functionalized titanate nanobelt powder. The strength and deformability of the marbles are adjustable by changing the intrinsic wetting state of the titanate nanoparticles. The excellent chemical stability of surface layer on the liquid marbles consisting of the titanate nanobelts provides the possibility for qualitative and quantitative chemical sensing under a wide range of pH values.Environment and Water Industry Programme Office (EWI) under the National Research Foundation of Singapore[MEWR651/06/160]; National Nature Science Foundation of China[20773100, 51072170, 20620130427]; National Basic Research Program of China (973 Program)[2007CB935603]; Technical Program of Fujian Province, China[2007H0031

Research on construction projects from a social network perspective: based on knowledge graph analysis

In order to comprehensively reflect the current status, research hotspots and evolutionary trends of research on construction projects from a social network perspective, 143 HJrelevant papers in the WoS database from 1999 to 2020 were taken as the research objects, and the bibliometric method and CiteSpace V were used to reveal the research development and evolution of the field during the 20 years and explore the future research trends. The study shows that the hotspots of construction project research from social network perspective include performance, governance, stakeholder management, risk management, and communication; research on construction project organizational network innovation, stakeholder risk and governance, BIM technology application, and social capital perspective to improve project organization become future research trends

Mitochondrial Cytochrome c Oxidase and F1Fo-ATPase Dysfunction in Peppers (Capsicum annuum L.) with Cytoplasmic Male Sterility and Its Association with orf507 and Ψatp6-2 Genes

Cytoplasmic male sterility (CMS) in pepper (Capsicum annuum L.) has been associated with novel genes in the mitochondria, such as orf507 and Ψatp6-2. Plant sterility has been proved to result from the rearrangement of the mitochondrial genome. Previous studies have demonstrated that orf507 is co-transcribed with the cox II gene, and Ψatp6-2 is truncated at the 3' region of the atp6-2 that is found in the maintainer line. Until this time, little has been known about the relationship between the novel gene and the function of its corresponding enzyme in mitochondria from the CMS pepper line. Moreover, the aberrant function of the mitochondrial enzymes is seldom reported in pepper. In this study, we observed that anther abortion occurred after the tetrad stage in the CMS line (HW203A), which was accompanied by premature programmed cell death (PCD) in the tapetum. The spatiotemporal expression patterns of orf507 and Ψatp6-2 were analyzed together with the corresponding enzyme activities to investigate the interactions of the genes and mitochondrial enzymes. The two genes were both highly expressed in the anther. The orf507 was down-regulated in HW203A (CMS line), with nearly no expression in HW203B (the maintainer line). In contrast, the cytochrome c oxidase activity in HW203A showed the opposite trend, reaching its highest peak at the tetrad stage when compared with HW203B at the same stage. The Ψatp6-2 in the CMS line was also down-regulated, but it was up-regulated in the maintainer line. The corresponding F1Fo-ATPase activity in the CMS line was gradually decreased along with the development of the anther, which showed the same trend for Ψatp6-2 gene expression. On the contrary, with up-regulated gene expression of atp6-2 in the maintainer line, the F1Fo-ATPase activity sharply decreased after the initial development stage, but gradually increased following the tetrad stage, which was contrary to what happened in the CMS line. Taken together, all these results may provide evidence for the involvement of aberrant mitochondrial cytochrome c oxidase and F1Fo-ATPase in CMS pepper anther abortion. Moreover, the novel orf507 and Ψatp6-2 genes in the mitochondria may be involved in the dysfunction of the cytochrome c oxidase and F1Fo-ATPase, respectively, which are responsible for the abortion of anthers in the CMS line

Self-organized TiO2 nanotube arrays with uniform platinum nanoparticles for highly efficient water splitting

Highly efficient water splitting electrode based on uniform platinum (Pt) nanoparticles on self-organized TiO2 nanotube arrays (TNTAs) was prepared by a combination of multi-step electrochemical anodization with facile photoreduction process. Uniform platinum (Pt) nanoparticles with an average diameter of 8 nm are distributed homogeneously on nanoporous top layer and underneath TiO2 nanotube wall. In comparison to pristine TNTAs, Pt@TNTAs show substantially enhanced photocurrent density and the incident photon-to-current conversion efficiency (IPCE) in the entire wavelength window. The maximum photocurrent density and IPCE from the optimized Pt@TNTAs photoelectrode (Pt, similar to 1.57 wt%) were about 24.2 mA cm(-2) and 87.9% at 350 nm, which is much higher than that of the pure nanotubes sample (16.3 mA cm(-2) and 67.3%). The resultant Pt@TNTAs architecture exhibited significantly enhanced photoelectrochemical activities for solar water splitting with hydrogen evolution rate up to 495 mu mol h(-1) cm(-2) in 2 M Na2CO3 + 0.5 M ethylene glycol under the optimal external bias of -0.3 V-SCE. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.National Natural Science Foundation of China [51072170, 21021002]; National Basic Research Program of China [2012CB932900]; Alexander von Humboldt (AvH) Foundation of German