Bis(2,2′-bipyrid­yl)bromidocopper(II) bromide bromo­acetic acid hemihydrate

In the title compound, [CuBr(C10H8N2)2]Br·BrCH2COOH·0.5H2O, the CuII ion is coordinated by four N atoms [Cu—N = 1.985 (6)–2.125 (7) Å] from two 2,2′-bipyridine ligand mol­ecules and a bromide anion [Cu—Br = 2.471 (2) Å] in a distorted trigonal-bipyramidal geometry. Short centroid–centroid distances [3.762 (5) and 3.867 (5) Å] between the aromatic rings of neighbouring cations suggest the existence of π–π inter­actions. Inter­molecular O—H⋯Br hydrogen bonds and weak C—H⋯O and C—H⋯Br inter­actions consolidate the crystal packing

Study on QSTR of Benzoic Acid Compounds with MCI

Quantitative structure-toxicity relationship (QSTR) plays an important role in toxicity prediction. With the modified method, the quantum chemistry parameters of 57 benzoic acid compounds were calculated with modified molecular connectivity index (MCI) using Visual Basic Program Software, and the QSTR of benzoic acid compounds in mice via oral LD50 (acute toxicity) was studied. A model was built to more accurately predict the toxicity of benzoic acid compounds in mice via oral LD50: 39 benzoic acid compounds were used as a training dataset for building the regression model and 18 others as a forecasting dataset to test the prediction ability of the model using SAS 9.0 Program Software. The model is LogLD50 = 1.2399 × 0JA +2.6911 × 1JA – 0.4445 × JB (R2 = 0.9860), where 0JA is zero order connectivity index, 1JA is the first order connectivity index and JB = 0JA × 1JA is the cross factor. The model was shown to have a good forecasting ability

High impact bug report identification with imbalanced learning strategies

Supplementary code and data available from GitHub: https://github.com/goddding/JCST</p

A simple and efficient method for extraction of Taq DNA polymerase

Background: Thermostable DNA polymerase (Taq Pol \u399) from Thermus aquaticus has beenwidely used in PCR, which was usually extracted with Pluthero's method. Themethod used ammonium sulfate to precipitate the enzyme, and it saved effort and money but not time. Moreover, we found that 30\u201340% activity of Taq Pol I was lost at the ammonium sulfate precipitation step, and the product contained a small amount of DNA. Results: We provided a novel, simplified and low-costmethod to purify the Taq Pol \u399 after overproduction of the enzyme in Escherichia coli , which used ethanol instead of ammonium sulfate to precipitate the enzyme. The precipitate can be directly dissolved in the storage buffer without dialysis. In addition, DNA and RNA contamination was removed with DNase I and RNase A before precipitation, and the extraction procedure was optimized. Our improvements increase recovery rate and specific activity of the enzyme, and save labor, time, and cost. Conclusions: Our method uses ethanol, DNase I, and RNase A to purify the Taq Pol \u399, and simplifies the operation, and increases the enzyme recovery rate and quality

Current induced resistance change of magnetic tunnel junctions with ultra-thin MgO tunnel barriers

Ultra-thin magnetic tunnel junctions with low resistive MgO tunnel barriers are prepared to examine their stability under large current stress. The devices show magnetoresistance ratios of up to 110 % and an area resistance product of down to 4.4 ohm micrometer squared. If a large current is applied, a reversible resistance change is observed, which can be attributed to two different processes during stressing and one relaxation process afterwards. Here, we analyze the time dependence of the resistance and use a simple model to explain the observed behavior. The explanation is further supported by numerical fits to the data in order to quantify the timescales of the involved phenomena