Error analysis of idealized nanopore sequencing

This numerical study provides an error analysis of an idealized nanopore sequencing method in which ionic current measurements are used to sequence intact single‐stranded DNA in the pore, while an enzyme controls DNA motion. Examples of systematic channel errors when more than one nucleotide affects the current amplitude are detailed, which if present will persist regardless of coverage. Absent such errors, random errors associated with tracking through homopolymer regions are shown to necessitate reading known sequences (Escherichia coli K‐12) at least 140 times to achieve 99.99% accuracy (Q40). By exploiting the ability to reread each strand at each pore in an array, arbitrary positioning on an error rate versus throughput tradeoff curve is possible if systematic errors are absent, with throughput governed by the number of pores in the array and the enzyme turnover rate.     

Anti-corrosion and anti-microbial evaluation of novel water-soluble bis azo pyrazole derivative for carbon steel pipelines in petroleum industries by experimental and theoretical studies

In this research, we investigated the synthesis of a novel water-soluble bis azo pyrazolin-5-one (ABP) which was synthesized efficiently via the regioselective reaction of hydrazine with coumarin hydrazone (CMH). Also, we evaluate their anti-corrosion and anti-bacterial behavior. The inhibition efficiency of ABP in an acidic medium (1.0 M HCl) was evaluated using various electrochemical and surface morphology measurements. The novel bis pyrazole-based azo dye ABP (16 × 10^?6 M) demonstrated a higher protection capacity (93.3 %). Tafel curves revealed that ABP was a mixed-type inhibitor. The adsorption of ABP on the C-steel (CS) surface is proven by the alteration in (R_ct and C_dl) impedance characteristics and obeyed the Langmuir isotherm model. SEM/EDX, AFM, and XPS surface examinations confirmed the enhancement of an adsorbed film protects the CS surface from acid corrosion at the appropriate dose. Furthermore, theoretical calculations using DFT and MC simulations were performed to identify the active sites on ABP molecules in charge of the adsorption and surface protection of the CS. The adsorption of bis pyrazole-based azo dye on the metal surface explained the protection mechanism. Moreover, the ABP screened for its antimicrobial activity against sulfate-reducing bacteria (SRB), and the calculated inhibition efficiency was 100 %. The current work presents significant results in manufacturing and producing novel water-soluble bis pyrazole-based azo dye derivative with high anti-corrosion and anti-microbial efficiency.     

DFT study on the chemical sensitivity of C3N nanotubes toward acetone

Potential application of single-walled C₃N nanotubes was investigated as chemical sensors for acetone molecules based on the density functional theory calculations. It was found that the pristine nanotube weakly adsorbs an acetone molecule with the adsorption energy of − 9.7 kcal/mol, and its electronic properties are not sensitive to this molecule. By replacing a C atom with a Si atom, the nanotube becomes a p-type semiconductor. The adsorption energy of the acetone molecule on the Si-doped nanotube becomes much more negative (E_ad=−67.4 kcal/mol). The adsorption process leads to a sizable increase in the resistance of the Si-doped tube, thereby, it can show the presence of acetone molecule, creating an electronic signal. Also, the sensitivity of these devices can be controlled by the doping level of Si atoms. By increasing the number of dopant atoms from 1 to 4, the sensitivity is gradually increased.     

Electrochemical devices obtained from biochar: Advances in renewable and environmentally-friendly technologies applied to analytical chemistry

Biochar is the carbon-rich material produced from organic feedstock such as agricultural wastes and municipal solid waste in limited oxygen atmosphere and under certain thermal combustion. Due to its high carbon content, high cation exchange capacity, large surface and stability structure, it has been applied in different field of knowledge. In relation to environment analytical chemistry the studies about biochar majorly focus in degradation of contaminants and soil and water remediation. However, due to its excellent electrical conductivity, biochar has been also applied to the manufacture of sensitive, robust, efficient and inexpensive devices applied to supercapacitor-based energy storage and chemically modified electrodes or sensors. Therefore, this review describes about obtention, modification and characterization of biochar as well as the pertinent aspects of electrochemical devises based on biochar and a general discussion about the environmental concern of biochar, challenges and prospects.     

原子吸收光度法测定钢铁及合金中的铌量

本法叙述了一氧化二氮－乙炔火焰原子吸收光度法测定铌量，用鞣酸沉淀分离和在盐酸－氢氟酸介质中加入增感剂三氯化铝，灵敏度１２μｇ／ｍＬ／１％吸收，检出限６．１μｇ／ｍＬ。     

7-(苯并噻唑-2-偶氮)-8-羟基喹啉-5-磺酸与镉显色反应的研究和应用

在 p H4 .8的邻苯二甲酸氢钾 - Na OH介质中 ,非离子表面活性剂 Tween- 80存在下 ,7- (苯并噻唑 - 2 -偶氮 ) - 8-羟基喹啉 - 5 -磺酸 (BTAQS)与镉形成 2∶ 1的紫红色配合物 ,其最大吸收波长 λmax=5 6 0 nm,表观摩尔吸光系数为 8.71× 10 4L· mol-1·cm-1,镉含量在 0— 6 μg/ 10 m L范围内服从比耳定律。用于矿样中镉的测定 ,相对误差小于 3% ,相对标准偏差小于 2 .5 % (n=5 )。     

Inverse estimation of indoor airflow patterns using singular value decomposition

The fast pace in the development of indoor sensors and communication technologies is allowing a great amount of sensor data to be utilized in various areas of indoor air applications, such as estimating indoor airflow patterns. The development of such an inverse model and the design of a sensor system to collect appropriate data are discussed in this study. Algebraic approaches, including singular value decomposition (SVD), are evaluated as methods to inversely estimate airflow patterns given limited sensor measurements. In lieu of actual sensor data, computational fluid dynamics data are used to evaluate the accuracy of the airflow patterns estimated by the inverse models developed in this study. It was found that the airflow patterns estimated by the linear inverse SVD model were as accurate as those estimated by the nonlinear inverse-multizone model. For the zones tested, sensor measurements along on the walls and near the inlet and outlet provided the greatest improvement in the accuracy of the estimated airflow patterns when compared with the results using measurements from other locations.     

基于STC单片机的紫外火焰探测器设计

介绍了一种基于STC单片机的紫外线火焰探测器。紫外传感器采用OSRAM公司的SFH530-R,设计了传感器信号处理电路获取火焰信号的闪烁频率及其辐射的紫外线强度,通过判断传感器输出交流量的频率及幅值来识别火焰,将直流量转换成0~5V电压信号输出指示火焰强度。     

A Chemical Proteomic Strategy Reveals Inhibitors of Lipoate Salvage in Bacteria and Parasites

The development of novel anti-infectives requires unprecedented strategies targeting pathways which are solely present in pathogens but absent in humans. Following this principle, we developed inhibitors of lipoic acid ( LA ) salvage, a crucial pathway for the survival of LA auxotrophic bacteria and parasites but non-essential in human cells. An LA -based probe was selectively transferred onto substrate proteins via lipoate protein ligase (LPL) in intact cells, and their binding sites were determined by mass spectrometry. Probe labeling served as a proxy of LPL activity, enabling in situ screenings for cell-permeable LPL inhibitors. Profiling a focused compound library revealed two substrate analogs ( LAMe and C3 ) as inhibitors, which were further validated by binding studies and co-crystallography. Importantly, LAMe exhibited low toxicity in human cells and achieved killing of Plasmodium falciparum in erythrocytes with an EC₅₀ value of 15 μM, making it the most effective LPL inhibitor reported to date.