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Transcriptional regulation is one of the key steps in determining gene expression. Diverse single-molecule techniques have been applied to characterize the stepwise progression of transcription, yielding complementary results. These techniques include, but are not limited to, fluorescence-based microscopy with single or multiple colors, force measuring and manipulating microscopy using magnetic field or light, and atomic force microscopy. Here, we summarize and evaluate these current methodologies in studying and resolving individual steps in the transcription reaction, which encompasses RNA polymerase binding, initiation, elongation, mRNA production, and termination. We also describe the advantages and disadvantages of each method for studying transcription. [ABSTRACT FROM AUTHOR]

Piezoelectric vibratory conveyors are widely used in many industrial fields such as factory automation. However, there is still a limitation for most cases that the vibratory conveyor can only feed in the designed direction. In today's multitasking intelligent machinery, how to sort different parts from the same feed source and convey them efficiently in different directions remains a challenge to be overcome. This study proposes an innovative design that uses a composite sinusoidal control signal to drive a linear two-stage piezoelectric vibratory feeder. By simply tuning the amplitude and phase of the input composite signal, the conveying velocity and direction can be altered easily. The dynamic characteristics of this feeder were both investigated by theoretical formulation and experimental measurement. It is found that the conveying performance of this feeder is better suited for using the composite signal with two sinusoidal components of double frequency. With the composite control signal synthesized by two sinusoidal components of 237.5 Hz and 475.0 Hz, which were close to the feeder's first two resonance frequencies to increase the response gain of the structure, and the input voltage of 60 V, which corresponded to the trough's displacement amplitude of 54.5 µm, the measured conveying speeds were +30.8 mm/s and -33.3 mm/s for setting the phase angles 180° and 0°, respectively. The result demonstrates the feasibility of the proposed two-way vibratory feeder design. [ABSTRACT FROM AUTHOR]

DNA interstrand crosslink (ICL) repair requires a complex network of DNA damage response pathways. Removal of the ICL lesions is vital, as they are physical barriers to essential DNA processes that require the separation of duplex DNA, such as replication and transcription. The Fanconi anemia (FA) pathway is the principal mechanism for ICL repair in metazoans and is coupled to DNA replication. In Saccharomyces cerevisiae, a vestigial FA pathway is present, but ICLs are predominantly repaired by a pathway involving the Pso2 nuclease, which is hypothesized to use its exonuclease activity to digest through the lesion to provide access for translesion polymerases. However, Pso2 lacks translesion nuclease activity in vitro, and mechanistic details of this pathway are lacking, especially relative to FA. We recently identified the Hrq1 helicase, a homolog of the disease-linked enzyme RecQ-like helicase 4 (RECQL4), as a component of Pso2-mediated ICL repair. Here, using genetic, biochemical, and biophysical approaches, including single-molecule FRET (smFRET)- and gel-based nuclease assays, we show that Hrq1 stimulates the Pso2 nuclease through a mechanism that requires Hrq1 catalytic activity. Importantly, Hrq1 also stimulated Pso2 translesion nuclease activity through a site-specific ICL in vitro. We noted that stimulation of Pso2 nuclease activity is specific to eukaryotic RecQ4 subfamily helicases, and genetic and biochemical data suggest that Hrq1 likely interacts with Pso2 through their N-terminal domains. These results advance our understanding of FA-independent ICL repair and establish a role for the RecQ4 helicases in the repair of these detrimental DNAlesions. [ABSTRACT FROM AUTHOR]

Abstract A DC electroplated Ni Mo coating in a citrate bath was used in this tribocorrosion study. The cylindrical specimen was tested in the block-on-ring configuration with immersion in 5 wt% NaCl solution and the applied overpotential ranging from open-circuit potential (OCP) to +600 mV SCE. The weight loss, composition and microstructure of the tested specimen were measured and examined. The polarization curve showed no passivation of corrosion film at high overpotential. Thus, a continuous increase of weight loss in simple corrosion with applied overpotential was observed. On the contrary, a minimum friction coefficient at +200 mV SCE was obtained due to the better oxide film lubrication and better liquid support from the enclosed pitted holes. The synergy effect of wear and corrosion on the weight loss of this Ni Mo alloy coating was found to be less dominant than its other Ni-alloy counterparts, such as Ni P, Ni W, and Ni-W-P. The passivation of the corrosion film was considered to be the main factor for this difference. Highlights • Electroplating of Ni Mo alloy with 5A/dm2 and Ni2+ molar ratio of 0.91 produced low strained coating. • Corrosion weight loss increased with applied overpotential while minimum friction obtained at +200 mV SCE. • Synergy between wear and corrosion was less dominant than simple corrosion. • Different synergy effect of Ni Mo alloy from others was caused by the passivation behavior. [ABSTRACT FROM AUTHOR]

Topoisomerases play crucial roles in DNA replication, transcription, and recombination. For instance, topoisomerase II (Top2) is critically important for resolving DNA tangles during cell division, and as such, it is a broad anticancer drug target. Top2 regulates DNA topology by transiently breaking one double-stranded DNA molecule (cleavage), allowing a second double strand to pass through the opened DNA gate (opening), and then closing the gate by rejoining the broken ends. Drugs that modulate Top2 catalysis may therefore affect enzymatic activity at several different steps. Previous studies have focused on examining DNA cleavage and ligation; however, the dynamic opening and closing of the DNA gate has been less explored. Here, we used the single-molecule Förster resonance energy transfer (smFRET) method to observe the open and closed state of the DNA gate and to measure dwell times in each state. Our results show that Top2 binds and bends DNA to increase the energy transfer efficiency (EFRET), and ATP treatment further induces the fluctuation of EFRET, representing the gate opening and closing. Additionally, our results demonstrate that both types of Top2-targeting anticancer drugs, the catalytic inhibitor dexrazoxane (ICRF187) and mechanistic poison teniposide (VM26), can interfere with DNA gate dynamics and shorten the dwell time in the closed state. Moreover, Top2 bound to the nonhydrolyzable ATP analog 5'-adenylyl-β,γ-imidodiphosphate exhibits altered DNA gate dynamics, but the DNA gate appears to open and close even after N-gate closure. In summary, we have utilized single-molecule detection to unravel Top2 DNA gate dynamics and reveal previously unknown effects of Top2 drugs on these dynamics. [ABSTRACT FROM AUTHOR]

Metamaterials are materials having artificially tailored internal structure and unusual physical and mechanical properties. Due to their unique characteristics, metamaterials possess great potential in engineering applications. This study proposes a tunable metamaterial for the applications in acoustic isolation. Therefore, a stopband in the dispersion curve can be created because of the energy gap. For the conventional metamaterial, the stopband is fixed. Although the metamaterial with tunable characteristics has been proposed in the literature to extend its working stopband, the efficacy is usually compromised. In this study, cantilevers of tunable shape memory materials (SMM) via controlled phase transformation are incorporated into the metamaterial plate. Its theoretical finite element formulation for determining the dynamic characteristics is established. The effect of the configuration of the SMM cantilever absorbers on the metamaterial plate for the desired stopband in wave propagation is simulated by using finite element model and a commercial multi-physics software. The result demonstrates the tunable capability on the stopband of the metamaterial plate under different activation controls of the SMM absorbers, and shows the ability to trap the vibration at the designed frequency and prevent vibration wave from propagating downstream in different absorber arrangements and alloy phases. It should be beneficial to precision machinery and defense industries which have desperate need in vibration and noise isolation. [ABSTRACT FROM AUTHOR]

Due to its widely tunable mechanical property and incompatibility with most solders, Ni-Mn alloy can become a viable candidate in the fabrication of testing probe for microelectronic devices. In this study, the electrodeposition of Ni-Mn alloy in nickel sulphamate electrolyte with the addition of manganese sulphate was investigated under direct current (DC) power source. The effects of current density and Mn2+ concentration in the electrolyte on the coating composition, cathodic efficiency, microstructure and mechanical properties were explored. The results showed that the raise of the Mn2+ concentration in the electrolyte alone did not effectively increase the Mn content in the coating but reduce the cathodic efficiency. On the other hand, increasing the current density facilitated the codeposition of the Mn and rendered the crystallite from coarse columnar grain to the refined one. Thus, both hardness and internal stress of the coating increased. The fabrication of testing probes at 1 A/dm² was shown to satisfy the high hardness, low internal stress, reasonable fatigue life, and nonsticking requirements for this microelectronic application. [ABSTRACT FROM AUTHOR]

Nickel alloy electrodes both in plane and nanowire morphologies were fabricated by electrodeposition in sulfamate bath. With the increasing concentration of phosphorous acid in the electrolyte, the P content in the deposition increased accordingly. In the meantime, the grain refined and even became amorphous in microstructure as the P content was raised. For the nanowire electrode, vibrating sample magnetometer (VSM) measurement showed that its coercivity was anisotropic and decreased with P-content. In addition, the easy axis for magnetization of the electrode was parallel to the axial direction of nanowire. The electrocatalytic activity measurement of the electrode in 0.5M H2SO4 electrolyte showed that the nanowire electrode had higher activity than the plane one, and the alloying of P in Ni electrode raised its hydrogen evolution reaction (HER) performance. The enhanced performance of nanowire electrode was attributed to the smaller and more uniform hydrogen bubbles generated in HER reaction. Finally, the applied magnetic field (3.2 T) improved significantly the HER activity of Ni but not Ni-P electrode. By using nanowire morphology and applying magnetic field, the current density at -0.75V HER stability test of the Ni electrode increased fourfold more than its plane counterpart. [ABSTRACT FROM AUTHOR]

Objective: The enormous job stress of police work may result in depression, which is highly correlated with work disability and poor quality of life. We investigated the quality of life, the probability of depression, and the related risk factors for police officers in Kaohsiung, Taiwan. Methods: We used the 12-item Short-Form Health Survey (SF-12) and the Disaster-Related Psychological Screening Test (DRPST) to assess the quality of life and prevalence of depression for 832 police officers in Kaohsiung. Results: The estimated rate of probable major depression was 21.6% (180/832). Those with an educational level of university or above and nondepressed police officers had higher scores in every subscale for quality of life. Police officers older than 50 had higher scores in the mental aspects of quality of life. Family problems and job stress related to achievement, peer pressure about performance, and heavy workloads were predictive factors for depression. Conclusion: Police officers might have a higher estimated rate of depression than previously thought, and those with depression have a poorer quality of life. [ABSTRACT FROM AUTHOR]