Rhinogobius houheensis, a new species of freshwater goby (Teleostei: Gobiidae) from the Houhe National Nature Reserve, Hubei province, China

Wanghe, Kunyuan, Hu, Faxiang, Chen, Minhao, Luan, Xiaofeng (2020): Rhinogobius houheensis, a new species of freshwater goby (Teleostei: Gobiidae) from the Houhe National Nature Reserve, Hubei province, China. Zootaxa 4820 (2): 351-365, DOI: https://doi.org/10.11646/zootaxa.4820.2.

Structural Insight into DNA-Dependent Activation of Human Metalloprotease Spartan

Summary: The DNA-dependent metalloprotease Spartan (SPRTN) cleaves DNA-protein crosslinks (DPCs) and protects cells from DPC-induced genome instability. Germline mutations of SPRTN are linked to human Ruijs-Aalfs syndrome (RJALS) characterized by progeria and early-onset hepatocellular carcinoma. The mechanism of DNA-mediated activation of SPRTN is not understood. Here, we report the crystal structure of the human SPRTN SprT domain bound to single-stranded DNA (ssDNA). Our structure reveals a Zn2+-binding sub-domain (ZBD) in SprT that shields its active site located in the metalloprotease sub-domain (MPD). The narrow catalytic groove between MPD and ZBD only permits cleavage of flexible substrates. The ZBD contains an ssDNA-binding site, with a DNA-base-binding pocket formed by aromatic residues. Mutations of ssDNA-binding residues diminish the protease activity of SPRTN. We propose that the ZBD contributes to the ssDNA specificity of SPRTN, restricts the access of globular substrates, and positions DPCs, which may need to be partially unfolded, for optimal cleavage. : Li et al. determine the crystal structure of human Spartan bound to DNA. Spartan is a DNA-activated metalloprotease that cleaves DNA-protein crosslinks to preserve genome stability. Spartan mutations cause progeria and liver cancer in humans. The structure provides important insights into how DNA activates the protease activity of Spartan. Keywords: DNA repair, genome instability, DNA-protein crosslinks, metalloprotease, Spartan, Zn2+ binding, RJAL

Clinical features and risk factors of COVID-19-associated liver injury and function: A retrospective analysis of 830 cases

Introduction and objectives: The incidence of liver injury (LI) in hospitalized COVID-19 patients ranged from 14% to 53% based on sole or multiple elevated indexes for LI. The aims of our study were to investigate the changes of parameters (ALT, AST) in LI and determine the risk factors for LI in a cohort of 830 COVID-19 patients. Methods: Demographic information, clinical features, and laboratory testing outcomes on admission were compared between patients with and without liver biochemistry abnormality (LBA). The same comparisons were performed between the LBA and LI groups. The updated RUCAM was used to determine the causality between drugs application and LI. Univariable and multivariable logistic regression analyses were used to explore the potential risk factors associated with LBA and LI. Results: A total of 227 (27.3%) patients exhibited LBA and 32 (3.9%) patients were categorized as having LI based on the diagnostic criteria. 32.6% (74/227) of the LBA patients had RUCAM score >3, whereas the non-LBA patients had a slight lower at rate of 24.2% (146/603) (P?=?0.047). Multivariable regression showed that a higher incidence of LBA was associated with hepatic hypoattenuation on computed tomography (CT) (odds ratio: 2.243, 95% confidence interval: 1.410–3.592, p?=?0.001), lymphocyte proportion 1?mg/dL (2.650, 1.845–3.806, p?1 (2.558, 1.820-3.596, p?1.0?mg/dL, lymphocyte proportion 1.7?mol/L are potential risk factors for LI

On the Viscoelastic Parameters of Gussasphalt Mixture Based on Modified Burgers Model: Deviation and Experimental Verification

Viscoelasticity is an important characteristic of gussasphalt mixtures. The aim of this study is to find the correct viscoelastic material parameters of the novel gussasphalt applied in the 4th Yangtze River Bridge based on the modified Burgers model. This study firstly derives the explicit Prony series form of the shear relaxation modulus of viscoelastic material from Laplace transformation, to fulfill the parameter inputting requirements of commonly used finite element software suites. Secondly, a kind of uniaxial penetration creep experiment on the gussasphalt mixtures is conducted. By fitting the creep compliance, the viscoelastic parameters characterized by the modified Burgers model are obtained. And thirdly, based on the viscoelastic test data of asphalt mixtures, the Prony series formula derived in this study is verified through the finite element simulation. The comparison results of the relative errors between the finite element simulation and the theoretical calculation confirm the reliability of the Prony series formulas deduced in this research. And finally, a stress-correcting method is proposed, which can significantly improve the accuracy of model parameters identification and reduce the relative error between the finite element simulation and the experimental data

Vibration-Assisted Roll-Type Polishing System Based on Compliant Micro-Motion Stage

This paper aims to create a high-quality surface based on the linear contact material removal mechanism. For this paper, a piezo-driven, flexure-based micro-motion stage was developed for the vibration-assisted roll-type precision polishing system. Meanwhile, the compliance matrix method was employed to establish the amplification ratio and compliance model of the flexure mechanism. The dimensions of the mechanism were optimized using the grey wolves optimization (GWO) algorithm, aiming to maximize the natural frequencies. Using the optimal parameters, the established models for the mechanical performance evaluation of the flexure stage were verified with the finite-element method. Through closed-loop test, it was proven that the proposed micro-motion stage performs well in positioning micro motions. Finally, high quality surface using silicon carbide (SiC) ceramic with 36 nm Sa was generated by the independently developed vibration-assisted roll-type polishing machine to validate the performance of the established polishing system

Development of a novel three degrees-of-freedom rotary vibration-assisted micropolishing system based on piezoelectric actuation

The limited degrees of freedom (DOF) and movement form of the compliant vibration-assisted processing device are inherent constraints of the polishing technique. In this paper, a concept of a 3-DOF rotary vibration-assisted micropolishing system (3D RVMS) is proposed and demonstrated. The 3-DOF means the proposed vibration-assisted polishing device (VPD) is driven by three piezo-electric (PZT) actuators. Compared with the current vibration-assisted polishing technology which generates a trajectory with orthogonal actuators or parallel actuators, a novel 3-DOF piezoelectrically actuated VPD was designed to enable the workpiece to move along the rotational direction. Meanwhile, the proposed VPD can deliver large processing stoke in mrad scale and can be operated at a flexible non-resonant mode. A matrix-based compliance modeling method was adopted for calculating the compliance and amplification ratio of the VPD. Additionally, the dynamic and static properties of the developed VPD were verified using finite element analysis. Then, the VPD was manufactured and experimentally tested to investigate its practical performance. Finally, various polished surfaces which used silicon carbide (SiC) ceramic as workpiece material were uniformly generated by the high-performance 3D RVMS. Compared with a nonvibration polishing system, surface roughness was clearly improved by introducing rotary vibration-assisted processing. Both the analysis and experiments verified the effectiveness of the present 3D RVMS for micro-machining surfaces

Study on the Characters of Phase-Shifted Fiber Bragg Grating in Asymmetric Perturbation and Its Application in Fiber Laser Acoustic Sensor

Abstract A π phase-shifted fiber Bragg grating theoretical model is established, and the effects of an asymmetric and symmetrical perturbation field on a phase-shifted fiber Bragg grating are investigated in this paper. The trends of wavelength shifting caused by effective refraction index of phase shift grating in symmetric and asymmetric acoustic field are investigated in detail. Then, the fiber laser acoustic sensors packaged in asymmetric and symmetrical structures are designed and tested, respectively. The results show that the acoustic response of the wavelength of the distributed feedback (DFB) fiber laser (FL) in an asymmetric packaging structure is much more sensitive than in that in the symmetrical structure. The sensor packaged in the asymmetrical structure has a better low frequency (0 Hz–500 Hz) performance and a higher sensitivity than that in the symmetrical structure, and the sensitivity is improved about 15 dB in average and 32.7 dB in maximum. It provides a new method to improve the sensitivity of the fiber acoustic sensor

Nicotinamide Promotes Cell Survival and Differentiation as Kinase Inhibitor in Human Pluripotent Stem Cells

Summary: Nicotinamide, the amide form of vitamin B3, is widely used in disease treatments and stem cell applications. However, nicotinamide's impact often cannot be attributed to its nutritional functions. In a vitamin screen, we find that nicotinamide promotes cell survival and differentiation in human pluripotent stem cells. Nicotinamide inhibits the phosphorylation of myosin light chain, suppresses actomyosin contraction, and leads to improved cell survival after individualization. Further analysis demonstrates that nicotinamide is an inhibitor of multiple kinases, including ROCK and casein kinase 1. We demonstrate that nicotinamide affects human embryonic stem cell pluripotency and differentiation as a selective kinase inhibitor. The findings in this report may help researchers design better strategies to develop nicotinamide-related stem cell applications and disease treatments. : In this report, Guokai Chen and colleagues show that nicotinamide is a kinase inhibitor with multiple targets. Nicotinamide improves human pluripotent stem cell (hPSC) survival as a ROCK inhibitor, and it also induces hPSC differentiation as a casein kinase 1 inhibitor. This discovery highlights nicotinamide's regulatory function beyond its common roles in metabolism, PARP, and sirtuin pathways. Keywords: nicotinamide, human pluripotent stem cell, cell survival, cell differentiation, kinase inhibito