ATP and nucleic acids competitively modulate LLPS of the SARS-CoV2 nucleocapsid protein.

SARS-CoV-2 nucleocapsid (N) protein with very low mutation rates is the only structural protein which not only functions to package viral genomic RNA, but also manipulates host-cell machineries, thus representing a key target for drug development. Recent discovery of its liquid-liquid phase separation (LLPS) opens up a new direction for developing anti-SARS-CoV-2 strategies/drugs. However, so far the high-resolution mechanism of its LLPS still remains unknown. Here by DIC and NMR characterization, we have demonstrated: 1) nucleic acids modulate LLPS by dynamic and multivalent interactions over both folded NTD/CTD and Arg/Lys residues within IDRs; 2) ATP with concentrations > mM in all living cells but absent in viruses not only binds NTD/CTD, but also Arg residues within IDRs with a Kd of 2.8 mM; and 3) ATP dissolves nucleic-acid-induced LLPS by competitively displacing nucleic acid from binding the protein. Our study deciphers that the essential binding of N protein with nucleic acid and its LLPS are targetable by small molecules including ATP, which is emerging as a cellular factor controlling the host-SARS-CoV-2 interaction. Fundamentally, our results imply that the mechanisms of LLPS of IDR-containing proteins mediated by ATP and nucleic acids appear to be highly conserved from human to virus.

Quantum State Preparation with Optimal Circuit Depth: Implementations and Applications.

Quantum state preparation is an important subroutine for quantum computing. We show that any n-qubit quantum state can be prepared with a Θ(n)-depth circuit using only single- and two-qubit gates, although with a cost of an exponential amount of ancillary qubits. On the other hand, for sparse quantum states with d⩾2 nonzero entries, we can reduce the circuit depth to Θ(log(nd)) with O(ndlogd) ancillary qubits. The algorithm for sparse states is exponentially faster than best-known results and the number of ancillary qubits is nearly optimal and only increases polynomially with the system size. We discuss applications of the results in different quantum computing tasks, such as Hamiltonian simulation, solving linear systems of equations, and realizing quantum random access memories, and find cases with exponential reductions of the circuit depth for all these three tasks. In particular, using our algorithm, we find a family of linear system solving problems enjoying exponential speedups, even compared to the best-known quantum and classical dequantization algorithms.

Arg/Lys-containing IDRs are cryptic binding domains for ATP and nucleic acids that interplay to modulate LLPS.

Most membrane-less organelles (MLOs) formed by LLPS contain both nucleic acids and IDR-rich proteins. Currently while IDRs are well-recognized to drive LLPS, nucleic acids are thought to exert non-specific electrostatic/salt effects. TDP-43 functions by binding RNA/ssDNA and its LLPS was characterized without nucleic acids to be driven mainly by PLD-oligomerization, which may further transit into aggregation characteristic of various neurodegenerative diseases. Here by NMR, we discovered unexpectedly for TDP-43 PLD: 1) ssDNAs drive and then dissolve LLPS by multivalently and specifically binding Arg/Lys. 2) LLPS is driven by nucleic-acid-binding coupled with PLD-oligomerization. 3) ATP and nucleic acids universally interplay in modulating LLPS by competing for binding Arg/Lys. However, the unique hydrophobic region within PLD renders LLPS to exaggerate into aggregation. The study not only unveils the first residue-resolution mechanism of the nucleic-acid-driven LLPS of TDP-43 PLD, but also decodes a general principle that not just TDP-43 PLD, all Arg/Lys-containing IDRs are cryptic nucleic-acid-binding domains that may phase separate upon binding nucleic acids. Strikingly, ATP shares a common mechanism with nucleic acids in binding IDRs, thus emerging as a universal mediator for interactions between IDRs and nucleic acids, which may underlie previously-unrecognized roles of ATP at mM in physiology and pathology.

Implementation Evaluation of a Cluster Randomized Controlled Trial to Promote the Use of Respiratory Protective Equipment Among Migrant Workers Exposed to Organic Solvents in Small and Medium-Sized Enterprises.

Background: While the effectiveness of several occupational healthcare interventions has been demonstrated, successful implementation of such programs among internal migrant workers (IMWs) in small and medium-sized enterprises (SMEs) has been limited. This study aimed to evaluate the implementation of a three-arm cluster randomized controlled trial promoting respiratory protective equipment (RPE) use among IMWs exposed to organic solvents in SMEs and to assess the association between participants' compliance and effectiveness of intervention. Methods: A total of 60 SMEs were randomly allocated to a low- or high-intensive intervention group, or a control group that did not receive any intervention. The low-intensive intervention group was subjected to both traditional and mHealth occupational health education. The high-intensive intervention group was subjected to the low-intensive group activities and peer education. The Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework was used to guide implementation evaluation of this 6-months intervention. Generalized linear mixed models (GLMMs) were used to evaluate the effects of participants' compliance with the intervention on the primary outcomes, regarding the appropriate use of RPE. Results: Of 4,527 potentially eligible participants, 1,211 individuals were enrolled, with a reach rate of 26.8%. Sixty of the 66 SMEs approached (90.9%) SMEs adopted the intervention. Fidelity to traditional education (100.0%) and mHealth intervention (97.5%) was higher than fidelity to peer education (20.0%). Peer leaders cited inconvenient time and unfamiliarity with peers as two major barriers to delivering peer education. Compared with the control group, IMWs who complied with the interventions in both groups were more likely to wear RPE appropriately [low-intensive group: adjusted odds ratio (aOR) = 2.58, 95% confidence interval (CI): 1.56-4.28; high-intensive group: aOR = 7.52, 95% CI: 3.72-15.23]. Most participants (95.8%) were satisfied with the program and 93.1% stated that they would maintain the use of RPE in the future. Conclusions: A multi-component occupational health intervention to promote the use of RPE among IMWs in SMEs was feasible and acceptable. Peer education had great potential to enhance the occupational health behavior of IMWs, and thus strategies to improve participants' adherence to this component warrant further investigation. Clinical Trial Registration: http://www.chictr.org.cn, identifier: ChiCTR-IOR-15006929.

Research about the capacitance properties of ion-induced multilayer and self-assembled monolayer Ti3C2T x.

MXenes materials are two-dimensional inorganic materials with abundant surface sites as capacitors. Better control of its morphology and expression of surface groups helps to improve the performance of capacitors. Herein, we controlled the morphology of MXenes with HF, HCl-LiF etching conditions, alkali and metal ions inducing factors. Benefiting from the nanostructures, the capacitance of HCl-LiF-prepared self-assembled monolayer Ti3C2T x soared to 370.96 F g-1 from 32.09 F g-1 of HF-etched multilaminate Ti3C2T x . As a result of the introduction of ions, the surface termination group is replaced by -OH with -F. Profit from this, the alkalized single-deck plicated Ti3C2T x exhibited a supernal capacitance up to 684.53 F g-1 because of the wrinkled morphology and more -OH terminal groups. Meanwhile, metal ion abduction brought some negative effects to electrochemical properties due to the oxidation of high-valent metal ions potentially.

Hamiltonian Simulation with Random Inputs.

The algorithmic error of digital quantum simulations is usually explored in terms of the spectral norm distance between the actual and ideal evolution operators. In practice, this worst-case error analysis may be unnecessarily pessimistic. To address this, we develop a theory of average-case performance of Hamiltonian simulation with random initial states. We relate the average-case error to the Frobenius norm of the multiplicative error and give upper bounds for the product formula (PF) and truncated Taylor series methods. As applications, we estimate average-case error for the digital Hamiltonian simulation of general lattice Hamiltonians and k-local Hamiltonians. In particular, for the nearest-neighbor Heisenberg chain with n spins, the error is quadratically reduced from O(n) in the worst case to O(sqrt[n]) on average for both the PF method and the Taylor series method. Numerical evidence suggests that this theory accurately characterizes the average error for concrete models. We also apply our results to error analysis in the simulation of quantum scrambling.

A Novel Fast-Setting Strontium-Containing Hydroxyapatite Bone Cement With a Simple Binary Powder System.

In recent years, strontium-substituted calcium phosphate bone cement (Sr-CPC) has attracted more and more attentions in the field of bone tissue repair due to its comprehensive advantages of both traditional CPC and Sr ions. In this study, a crucial Sr-containing α-Ca3 - x Sr x (PO4)2 salt has been synthesized using a simplified one-step method at lower synthesis temperature. A novel Sr-CPC has been developed based on the simple binary Sr-containing α-Ca3 - x Sr x (PO4)2/Ca4(PO4)2O cement powder. The physicochemical properties and hydration mechanism of this Sr-CPC at various Sr contents were intensively investigated. The setting product of this Sr-CPC after a set for 72 h is a single-phase Sr-containing hydroxyapatite, and its compressive strength slightly decreased and its setting time extended with the increase of Sr content. The hydration process included the initial formation of the medium product CaHPO4⋅2H2O (30 min∼1 h), the following complete hydration of Ca4(PO4)2O and the initially formed CaHPO4⋅2H2O (2∼6 h), and the final self-setting of α-Ca3 - x Sr x (PO4)2 (6 h∼). The compressive strength of Sr-CPC, which was closely related to the transformation rate of Sr-containing hydroxyapatite, tended to increase with the extension of hydration time. In addition, Sr-CPC possessed favorable cytocompatibility and the effect of Sr ions on cytocompatibility of Sr-CPC was not obvious at low Sr contents. The present study suggests α-Ca3 - x Sr x (PO4)2 is a kind of vital Sr-containing salt source which is useful to develop some novel Sr-containing biomaterials. In addition, the new Sr-containing cement system based on this simple binary α-Ca3 - x Sr x (PO4)2/Ca4(PO4)2O cement powder displayed an attractive clinical application potential in orthopedics.

Improvement of Moloney murine leukemia virus reverse transcriptase thermostability by introducing a disulfide bridge in the ribonuclease H region.

Moloney murine leukemia virus (MMLV) reverse transcriptase (RT) is widely used in research and clinical diagnosis. Improvement of MMLV RT thermostability has been an important topic of research for increasing the efficiency of cDNA synthesis. In this study, we attempted to increase MMLV RT thermostability by introducing a disulfide bridge in its RNase H region using site-directed mutagenesis. Five variants were designed, focusing on the distance between the two residues to be mutated into cysteine. The variants were expressed in Escherichia coli and purified. A551C/T662C was determined to be the most thermostable variant.

Insight into the mechanism of thermostabilization of GH10 xylanase from Bacillus sp. strain TAR-1 by the mutation of S92 to E.

The mechanism of thermostabilization of GH10 xylanase, XynR, from Bacillus sp. strain TAR-1 by the mutation of S92 to E was investigated. Thermodynamic analysis revealed that thermostabilization was driven by the decrease in entropy change of activation for thermal inactivation. Crystallographic analysis suggested that this mutation suppressed the fluctuation of the amino acid residues at position 92-95.

Downregulation of microRNA-30c-5p was responsible for cell migration and tumor metastasis via COTL1-mediated microfilament arrangement in breast cancer.

BACKGROUND: Breast cancer metastasis is the main problem that affects the therapy and prognosis of breast cancer patients. Studies have indicated the role of microRNAs in breast cancer regulation, but the mechanisms are largely unknown. METHODS: In this study, we determined the expression of microRNA-30c-5p (miR-30c-5p) and coactosin-like protein 1 (COTL1) gene in breast cancer tissues, and revealed their effects on breast cancer metastasis regulation. Breast cancer and paracancerous tissues were collected. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to analyze the expression of miR-30c-5p and COTL1, and breast cancer cell line (MCF-7) was employed to verify the relationship between miR-30c-5p and COTL1. Western blot analysis and immunofluorescence were used for proteins analysis and microfilament observation, respectively. A dual-luciferase reporter gene was used for microRNA-gene interaction assay. RESULTS: The results showed that the expression of miR-30c-5p decreased, while the expression of COTL1 increased in breast cancer tissues. The results of luciferase reporting gene assay showed that, COTL1 was the target of miR-30c-5p. After miR-30c-5p was upregulated, the expression of COTL1 was reduced, microfilament arrangement was in disorder, and cell migration ability was inhibited. After miR-30c-5p was downregulated, the expression of COTL1 was increased, and the cell migration ability was enhanced. COTL1 protein expression levels were significantly higher in cancer tissues with lymph node metastasis. CONCLUSIONS: These findings indicate that miR-30c-5p/COTL1 pathway regulates breast cancer metastasis and can be used as a potential therapy target.

Results of a Cluster Randomized Controlled Trial to Promote the Use of Respiratory Protective Equipment among Migrant Workers Exposed to Organic Solvents in Small and Medium-Sized Enterprises.

Background: Existing evidence shows an urgent need to improve respiratory protective equipment (RPE) use, and more so among migrant workers in small and medium-sized enterprises (SMEs). The study aimed to assess the effectiveness of a behavioral intervention in promoting the appropriate use of RPE among internal migrant workers (IMWs) exposed to organic solvents in SMEs. Methods: A cluster randomized controlled trial was conducted among 1211 IMWs from 60 SMEs in Baiyun district in Guangzhou, China. SMEs were deemed eligible if organic solvents were constantly used in the production process and provided workers with RPE. There were 60 SMEs randomized to three interventions on a 1:1:1 ratio, namely a top-down intervention (TDI), a comprehensive intervention, and a control group which did not receive any intervention. IMWs in the comprehensive intervention received a module encompassing three intervention activities: An occupational health education and training component (lectures and leaflets/posters), an mHealth component in the form of messages illustrative pictures and short videos, and a peer education component. The TDI incorporated two intervention activities, namely the mHealth and occupational health education and training components. The primary outcome was the self-reported appropriate RPE use among IMWs, defined as using an appropriate RPE against organic solvents at all times during the last week before measurement. Secondary outcomes included IMWs' occupational health knowledge, attitude towards RPE use, and participation in occupational health check-ups. Data were collected and assessed at baseline, and three and six months of the intervention. Generalized linear mixed models were performed to evaluate the effectiveness of the trial. Results: Between 3 August 2015 and 29 January 2016, 20 SMEs with 368 IMWs, 20 SMEs with 390 IMWs, and 20 SMEs with 453 IMWs were assigned to the comprehensive intervention, the TDI, and the control group, respectively. At three months, there were no significant differences in the primary and secondary outcomes among the three groups. At six months, IMWs in both intervention groups were more likely to appropriately use RPE than the control group (comprehensive intervention: Adjusted odds ratio: 2.99, 95% CI: 1.75-5.10, p < 0.001; TDI: 1.91, 95% CI: 1.17-3.11, and p = 0.009). Additionally, compared with the control group, the comprehensive intervention also improved all three secondary outcomes. Conclusions: Both comprehensive and top-down interventions were effective in promoting the appropriate use of RPE among IMWs in SMEs. The comprehensive intervention also enhanced IMWs' occupational health knowledge, attitude, and practice. Trial registration: ChiCTR-IOR-15006929. Registered on 15 August 2015.

A Comparative Study on Johnson Cook, Modified Zerilli-Armstrong, and Arrhenius-Type Constitutive Models to Predict Compression Flow Behavior of SnSbCu Alloy.

The flow behavior of the SnSbCu alloy is studied experimentally by the compression tests in the range of the strain rates from 0.0001 to 0.1 s-1 and temperature from 293 to 413 K. Based on the experimental data, three constitutive models including the Johnson-Cook (J-C), modified Zerilli-Armstrong (Z-A), and Arrhenius-type (A-type) models are compared to find out an optimum model to describe the flow behavior of the SnSbCu alloy. The results show that the J-C model could predict the flow behavior of the SnSbCu alloy accurately only at some specific strain rates and temperature near the reference values. The modified Z-A and A-type constitutive models can give better fitting results than the J-C model. While, at high strains, the predictive values of the modified Z-A model have larger errors than those at low strains, which means this model has limitations at high strains. By comparison, the A-type model could predict the experimental results accurately at the whole strain range, which indicates that it is a more suitable choice to describe the flow behavior of the SnSbCu alloy in the focused range of strain rates and temperatures. The work is beneficial to solve the tribological problem of the bearing of the marine engine by integrating the accurate constitutive model into the corresponding numerical model.

Accurate fidelity analysis of the reverse transcriptase by a modified next-generation sequencing.

We evaluated fidelity of various reverse transcriptases (RTs) by a novel method with modified next-generation sequencing (NGS). In the optimized condition, one NGS run could handle cDNA products from multiple cDNA synthesis reactions performed at different conditions. This was achieved using a primer containing not only the tag of 14 randomized bases to label each cDNA molecule but also a tag of five bases to label each reaction condition. With this method, we quantitated the error rates of 44 cDNA synthesis reactions by retroviral RTs or genetically engineered DNA polymerases with RT activity under different conditions. The results indicated that high concentrations of MgCl2, Mn(OCOCH3)2, and dNTP decrease the fidelity and that these effects are more pronounced in reactions using RT from human immunodeficiency virus type 1. This is the first report about a precise fidelity monitoring of various RTs by a direct sequence determination.

Aliasing Signal Separation of Superimposed Abrasive Debris Based on Degenerate Unmixing Estimation Technique.

Leakage is the most important failure mode in aircraft hydraulic systems caused by wear and tear between friction pairs of components. The accurate detection of abrasive debris can reveal the wear condition and predict a system's lifespan. The radial magnetic field (RMF)-based debris detection method provides an online solution for monitoring the wear condition intuitively, which potentially enables a more accurate diagnosis and prognosis on the aviation hydraulic system's ongoing failures. To address the serious mixing of pipe abrasive debris, this paper focuses on the superimposed abrasive debris separation of an RMF abrasive sensor based on the degenerate unmixing estimation technique. Through accurately separating and calculating the morphology and amount of the abrasive debris, the RMF-based abrasive sensor can provide the system with wear trend and sizes estimation of the wear particles. A well-designed experiment was conducted and the result shows that the proposed method can effectively separate the mixed debris and give an accurate count of the debris based on RMF abrasive sensor detection.

Generation of thermostable Moloney murine leukemia virus reverse transcriptase variants using site saturation mutagenesis library and cell-free protein expression system.

We attempted to increase the thermostability of Moloney murine leukemia virus (MMLV) reverse transcriptase (RT). The eight-site saturation mutagenesis libraries corresponding to Ala70-Arg469 in the whole MMLV RT (Thr24-Leu671), in each of which 1 out of 50 amino acid residues was replaced with other amino acid residue, were constructed. Seven-hundred and sixty eight MMLV RT clones were expressed using a cell-free protein expression system, and their thermostabilities were assessed by the temperature of thermal treatment at which they retained cDNA synthesis activity. One clone D200C was selected as the most thermostable variant. The highest temperature of thermal treatment at which D200C exhibited cDNA synthesis activity was 57ºC, which was higher than for WT (53ºC). Our results suggest that a combination of site saturation mutagenesis library and cell-free protein expression system might be useful for generation of thermostable MMLV RT in a short period of time for expression and selection.

Study protocol: a cluster randomized controlled trial to assess the effectiveness of a multi-pronged behavioural intervention to improve use of personal protective equipment among migrant workers exposed to organic solvents in small and medium-sized enterprises.

BACKGROUND: In China, most of migrant workers work in the small and medium-sized enterprises (SMEs) and are a vulnerable group for occupational health. Migrant workers are at increased risk of occupational health risks due to poor occupational health behaviours such as the low use of personal protective equipment (PPE). However, there is a lack of solid evidence regarding how to improve the use of PPE among migrant workers in SMEs. The current study will assess the effectiveness of a multi-pronged behavioural intervention designed to promote PPE utilization among migrant workers exposed to organic solvents in SMEs. METHODS/DESIGN: This is a single blind, three-arm cluster randomized trial with 60 SMEs equally randomized to receive a top-down intervention (i.e. general health education and mHealth intervention provided by researchers) or a comprehensive intervention (which includes both top-down intervention and peer education) or a control condition (participants will not receive the intervention, but study measures will be obtained). Interventions will be conducted at the SMEs level for 6 months and all eligible migrant workers in these SMEs will be enrolled into the trial. The primary outcome is effective use of PPE during the last week. The secondary outcomes are occupational health knowledge and attitude and participation in occupational health check-up. Data will be collected and assessed at baseline; 3 months post baseline and the end of the intervention. DISCUSSION: This theory- and evidence based intervention will contribute to the limited evidence of behaviour change intervention in improving PPE utilization of migrant workers in SMEs, and provide timely evidence for the development of basic occupational health services in China and elsewhere with similar industrialization contexts. TRIAL REGISTRATION: ChiCTR-IOR-15006929 . Registered on 16 August 2015.

Genetic variant in CXCL13 gene is associated with susceptibility to intrauterine infection of hepatitis B virus.

Intrauterine infection of hepatitis B virus (HBV), which accounts for the majority of mother-to-child transmission, is one of the main reasons for the failure of combined immunoprophylaxis against the transmission. Recent studies have identified that genetic background might influence the susceptibility to intrauterine infection of HBV. We conducted this study to investigate the associations between 10 genetic variants in 9 genes (SLC10A1, HLA-DP, HLA-C, CXCR5, CXCL13, TLR3, TLR4, TLR9 and UBE2L3) of mothers and their neonates and HBV intrauterine infection. A significantly decreased risk of HBV intrauterine transmission were found among mothers who carried the rs355687 CT genotypes in CXCL13 gene compared to those with CC genotypes (OR = 0.25, 95% CI, 0.08-0.82, P = 0.022); and a marginally significantly decreased risk was also observed under the dominant model (OR = 0.34, 95% CI, 0.11-1.01, P = 0.052). Besides, neonatal rs3130542 in HLA-C gene was found to be marginally significantly associated with decreased risk of HBV intrauterine infection under the additive model (OR = 0.55, 95% CI, 0.29-1.04, P = 0.064). However, we found no evidence of associations between the remaining 8 SNPs and risk of HBV intrauterine infection among mothers and their neonates. In conclusion, this study suggested that genetic variant in CXCL13 gene was associated with susceptibility to intrauterine infection of HBV.

Controversy and Strategies Exploration in Blocking Mother-to-Child Transmission of Hepatitis B.

Hepatitis B, a serious infectious disease caused by the hepatitis B virus (HBV), remains a worldwide social and public health problem. Hepatitis B has a particularly high incidence rate in the world, whereas approximately 35-50% HBV carriers are infected through vertical transmission. Even after newborn immunoprophylaxis, vertical transmission still accounts for 5-10% in China according to plenty of literature in Chinese language. For these reasons, it is important to determine how to effectively intervene in mother-to-child transmission (MTCT). To date, though, intervention methods and measures remain controversial. In order to understand the mechanism of MTCT intervention further and develop effective preventions and interventions, a comprehensive analysis and presentation on some of its more controversial issues will be given in this paper. And eventually we conclude three measures and strategies for these issues: (1) emancipate the mind and seek truth from facts to understand the controversial issues pertaining to MTCT of HBV; (2) treat the basic rules and changing characteristics of MTCT blocking process of hepatitis B with holistic medical thought dialectically and (3) further explore the interaction of genetic susceptibility and environmental factors of MTCT of hepatitis B.

[Fractal structure of Abies fabri, dominant tree species in dark coniferous forest at the upper reach of Yangtze River].

Based on the theory of fractal geometry, branching patterns of primitive Abies fabri in the dark coniferous forest ecosystem at the upper reach of Yangtze River were studied. The results showed that the maximum crown width was appeared at inferior 20% of the crown height, and its volume could be simulated by the combination of a round table and a cone. The surface of the crown and their branching patterns of Abies fabri had the common typical fractal characters, the fractal dimensions (FD) were 2.3232 and 1.8119, and the correlation coefficient was 0.99.

[Plot analysis in the dark coniferous ecosystem using GPS and GIS techniques].

It is generally difficult to survey in primary forests located on high-altitude region. However, it is convenient to identify and to recognize plots accompanied by GPS and GIS techniques, which can also display the spatial pattern of arbors precisely. Using the method of rapid-static positioning cooperated with tape-measure, it is concluded that except some points, the positioning was relatively precise, the average value of RMS was 2.84, variance was 2.96, and delta B, delta L, and delta H were 1.2, 1.2, and 4.3 m with their variances being +/- 0.6, +/- 1.1, and +/- 21.1, respectively, which could meet the needs of forestry management sufficiently. Accompanied by some other models, many ecological processes under small and even medium scale, such as the dynamics of gap succession, could also be simulated visually by GIS. Therefore, the techniques of "2S" were patent for forest ecosystem management under the fine scale, especially in the area of high altitude.