Validity of single-channel model for a spin-orbit coupled atomic Fermi gas near Feshbach resonances

We theoretically investigate a Rashba spin-orbit coupled Fermi gas near Feshbach resonances, by using mean-field theory and a two-channel model that takes into account explicitly Feshbach molecules in the close channel. In the absence of spin-orbit coupling, when the channel coupling $g$ between the closed and open channels is strong, it is widely accepted that the two-channel model is equivalent to a single-channel model that excludes Feshbach molecules. This is the so-called broad resonance limit, which is well-satisfied by ultracold atomic Fermi gases of $^{6}$Li atoms and $^{40}$K atoms in current experiments. Here, with Rashba spin-orbit coupling we find that the condition for equivalence becomes much more stringent. As a result, the single-channel model may already be insufficient to describe properly an atomic Fermi gas of $^{40}$K atoms at a moderate spin-orbit coupling. We determine a characteristic channel coupling strength $g_{c}$ as a function of the spin-orbit coupling strength, above which the single-channel and two-channel models are approximately equivalent. We also find that for narrow resonance with small channel coupling, the pairing gap and molecular fraction is strongly suppressed by SO coupling. Our results can be readily tested in $^{40}$K atoms by using optical molecular spectroscopy.Comment: 6 pages, 6 figure

Temporal and spatial distributions of soil nutrients in Hani terraced paddy fields, Southwestern China

AbstractHani terraced paddy fields are one of the most important ways for agricultural products and greatly influence regional landscapes in mountainous areas of Southwestern China. However, the knowledge of soil nutrient conditions from Hani terraced paddy fields is limited. This paper investigates such soil nutrient parameters as organic matter (OM), total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), total potassium (TK), available potassium (AK) of four sampling sites of paddy fields under special geographical environment and agricultural technology, and compares the differences of soil nutrients related to spatial patterns and temporal periods. Correlation analysis is performed to analyze the impact of environmental factors on soil nutrients, as well as the relationships between soil nutrient parameters and altitude, slope direction, gradient and distance from village. The results show that there were some differences separately in the content of soil nutrients such as OM, TN, TP, AP, TK and AK. The AK and AP levels are lower in the fallow period than that in the tillage period, only OM level in the fallow period is higher than that in the tillage period; TN, TK, TP levels are nearly similar in the tillage and the fallow period. Unlike great differences in two periods, soil nutrient content in the ridge of fields is identical basically with the content in the corresponding paddy fields. Correlation analysis shows that soil nutrients of AK, TP, TN and OM have distinctive negative correlations with distance from villages, while AP and TK display a slight fluctuation

A comparative study of natural immune responses against Plasmodium vivax C-terminal merozoite surface protein-1 (PvMSP-1) and apical membrane antigen-1 (PvAMA-1) in two endemic settings

The mechanisms of cellular and humoral immune responses against P. vivax parasite remain poorly understood. Several malaria immunological studies have been conducted in endemic regions where both P. falciparum and P. vivax parasites co-exist. In this study, a comparative analysis of immunity to Plasmodium vivax antigens in different geography and incidence of Plasmodium spp. infection was performed. We characterised antibodies against two P. vivax antigens, PvMSP-1 and PvAMA-1, and the cross-reactivity between these antigens using plasma from acute malaria infected patients living in the central region of China and in the western border of Thailand. P. vivax endemicity is found in central China whereas both P. vivax and P. falciparum are endemic in Thailand. There was an increased level of anti-PvMSP-1/anti-PvAMA-1 in both populations. An elevated level of antibodies to total P. vivax proteins and low level of antibodies to total P. falciparum proteins was found in acute P. vivax infected Chinese, suggesting antibody cross-reactivity between the two species. P. vivax infected Thai patients had both anti-P. vivax and anti-P. falciparum antibodies as expected since both species are present in Thailand. More information on humoral and cell mediated immunity during acute P. vivax-infection in the area where only single P. vivax species existed is of great interest in the relation of building up anti-disease severity caused by P. falciparum. This knowledge will support vaccine development in the future

Global Transcriptome Changes of Biofilm-Forming Staphylococcus epidermidis Responding to Total Alkaloids of Sophorea alopecuroides

Transcriptome changes of biofilm-forming Staphylococcus epidermidis response to total alkaloids of Sophorea alopecuroides was observed. Bioinformatic analyses were further used to compare the differential gene expression between control and the treated samples. It was found that 282 genes were differentially expressed, with 92 up-regulated and 190 down-regulated. These involved down-regulation of the sulfur metabolism pathway. It was suggested that inhibitory effects on Staphylococcus epidermidis and its biofilm formation of the total alkaloids of S. alopecuroides was mainly due to the regulation of the sulfur metabolism pathways of S. epidermidis

TRACE ELEMENTS MAY BE RESPONSIBLE FOR MEDICINAL EFFECTS OF SAUSSUREA LANICEPS, SAUSSUREA INVOLUCRATE, LYCIUM BARBARUM AND LYCIUM RUTHENICUM

Background: The pharmacodynamics of Saussurea laniceps, Saussurea involucrata, Lycium barbarum and Lycium ruthenicum have been researched, and trace elements have been considered as the essential elements, but little attention has been paid to the trace elements of the herbal medicine. We would like to report on the content of copper (Cu), manganese (Mn), iron (Fe), zinc (Zn) and selenium (Se) levels in the four herbal medicines. Materials and Methods: A total of 20 whole plant materials were collected of each species in China. The content of Cu, Mn, Fe and Zn in the dried aerial parts was estimated by the standard atomic absorption spectrophotometry. The level of Se was detected using hydride generation atomic fluorescence spectrometry. Results: The mean concentrations of Cu, Mn, Fe, Zn and Se in S. laniceps were 7.758±0.924μg/g, 201.3±16.24μg/g, 222.7±35.10μg/g, 18.48±2.913μg/g and 1.42±0.16μg/g, respectively; S. involucrata were 19.56±2.20μg/g, 88.75±8.53μg/g, 812.7±126.9μg/g, 34.85±3.81μg/g and 1.04±0.05μg/g, respectively; L. barbarum were 10.83±0.26μg/g, 9.598±0.32μg/g, 55.65±3.83μg/g, 11.92±0.27μg/g and 11.84±0.59μg/kg, respectively; L. ruthenicum were 12.67±0.39μg/g, 13.78±1.13μg/g, 98.04±5.03μg/g, 14.46±1.27μg/g and 35.12±2.34μg/kg, respectively. Conclusion: This study provided the trace elements content of Cu, Mn, Fe, Zn and Se in the four herbal medicines. The trace elements are maybe other functional compounds for medicinal effects. Deep relationship between pharmacological and trace elements contents, especially its mechanism of action should be future research

Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer.

Engineering magnetic anisotropy in two-dimensional systems has enormous scientific and technological implications. The uniaxial anisotropy universally exhibited by two-dimensional magnets has only two stable spin directions, demanding 180° spin switching between states. We demonstrate a previously unobserved eightfold anisotropy in magnetic SrRuO3 monolayers by inducing a spin reorientation in (SrRuO3)1/(SrTiO3) N superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial 〈001〉 direction (N < 3) to eightfold 〈111〉 directions (N ≥ 3). This eightfold anisotropy enables 71° and 109° spin switching in SrRuO3 monolayers, analogous to 71° and 109° polarization switching in ferroelectric BiFeO3. First-principle calculations reveal that increasing the SrTiO3 layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO3 monolayer easy axis. Our work demonstrates that correlation effects can be exploited to substantially change spin-orbit interactions, stabilizing unprecedented properties in two-dimensional magnets and opening rich opportunities for low-power, multistate device applications

Genome-wide identification and characterization of LcCCR13 reveals its potential role in lignin biosynthesis in Liriodendron chinense

IntroductionWood formation is closely related to lignin biosynthesis. Cinnamoyl-CoA reductase (CCR) catalyzes the conversion of cinnamoyl-CoA to cinnamaldehydes, which is the initiation of the lignin biosynthesis pathway and a crucial point in the manipulation of associated traits. Liriodendron chinense is an economically significant timber tree. Nevertheless, the underlying mechanism of wood formation in it remains unknown; even the number of LcCCR family members in this species is unclear.Materials and ResultsThis study aimed to perform a genome-wide identification of genes(s) involved in lignin biosynthesis in L. chinense via RT-qPCR assays and functional verification. Altogether, 13 LcCCR genes were identified that were divided into four major groups based on structural and phylogenetic features. The gene structures and motif compositions were strongly conserved between members of the same groups. Subsequently, the expression patterns analysis based on RNA-seq data indicated that LcCCR5/7/10/12/13 had high expression in the developing xylem at the stem (DXS). Furthermore, the RT-qPCR assays showed that LcCCR13 had the highest expression in the stem as compared to other tissues. Moreover, the overexpression of the LcCCR13 in transgenic tobacco plants caused an improvement in the CCR activity and lignin content, indicating that it plays a key role in lignin biosynthesis in the stems.DiscussionOur research lays a foundation for deeper investigation of the lignin synthesis and uncovers the genetic basis of wood formation in L. chinense

Closed-channel block of BK potassium channels by bbTBA requires partial activation

Blockade of large-conductance Ca2+-activated K+ (BK) channels by the bulky quaternary ammonium compound, N-(4-[benzoyl]benzyl)-N,N,N-tributylammonium (bbTBA), exhibits features consistent with blockade of both closed and open states. Here, we examine block of closed BK channels by bbTBA and how it may differ from block of open channels. Although our observations generally confirm earlier results, we describe three observations that are inconsistent with a model in which closed and open channels are equally accessible to blockade by bbTBA. First, block by bbTBA exhibits Ca2+-dependent features that are inconsistent with strictly state-independent block. Second, the steady-state voltage dependence of bbTBA block at negative potentials shows that any block of completely closed states either does not occur or is completely voltage independent. Third, determination of the fractional unblock by bbTBA at either low or high Ca2+ reveals deviations from a model in which open- and closed-state block is identical. The results support the view that bbTBA blockade of fully closed channels does not occur. We imagine two general types of explanation. First, a stronger voltage dependence of closed-channel block may minimize the contribution of closed-channel block at negative potentials. Second, voltage-dependent conformational changes among closed-channel states may permit block by bbTBA. The analysis supports the latter view, suggesting that bbTBA blockade of fully closed channels does not occur, but the ability of bbTBA to block a closed channel requires movement of one or more voltage sensors. Models in which block is coupled to voltage sensor movement can qualitatively account for (1) the ability of open-channel block to better fit block of conductance–voltage curves at high Ca2+; (2) the voltage dependence of fractional availability; and (3) the fractional unblock at different open probabilities. BK channels appear to undergo voltage-dependent conformational changes among closed states that are permissive for bbTBA block