Three-Component,One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Catalyzed by TiCl4-SiO2 Under Conventional Heating Conditions or Microwave Irradiation

In this study, silica-supported titanium tetrachloride was prepared and used as a novel catalyst for rapid and efficient synthesis of 2,4,5-trisubstituted imidazoles by a three-component, one-pot condensation of 1,2-diketones and aryl aldehydes in excellent yield under solvent-free conditions using conventional heating or microwave irradiation.

Bismuth-containing layered double hydroxide as a novel efficient photocatalyst for degradation of methylene blue under visible light

Layered double hydroxide (LDH)-based photocatalysts have emerged as a very promising candidate to replace TiO₂, owing to their unique layered structure, tunable band gaps, low cost, ease of scale-up, and good photocatalytic activity. Bismuth-doped ZnCr-LDH was studied as photocatalyst in the photodegradation of methylene blue (MB). The structure and morphology of ZnCr-LDH and ZnCrBi-LDH were characterized using a different mode of delegated tools, e.g., FTIR, XRD, UV–Vis, FESEM–EDX, and TEM measurements. FESEM and TEM image of the synthesized LDHs showed that the synthesized LDH is smooth overlapping crystals, and they are approximately in hexagonal form. The material was found to be a good photocatalyst for degradation of methylene blue in visible light, and the results showed that the photocatalytic activity of ZnCrBi-LDH sample is higher than of ZnCr-LDH sample. According to the kinetic data, the reaction rate constant of ZnCrBi-LDH is approximately four times higher than the apparent reaction rate constant of ZnCr-LDH. The catalytic activity was retained even after four methylene blue degradation cycles, indicating that the LDH could be an important addition to the field of wastewater treatment.     

A general approach to high-yielding asymmetric synthesis of chiral 3-alkyl-4-nitromethylchromans via cascade Barbas-Michael and acetalization reactions

A general approach to the high-yielding asymmetric synthesis of chiral 3-alkyl-4-nitromethylchromans as drug intermediates was achieved through cascade Barbas-Michael and acetalization (BMA) reactions on 2-(2-nitrovinyl)phenols with aldehydes in the presence of a catalytic amount of (R)-DPPOTMS and PhCO(2)H. Herein, we have also demonstrated the application of chiral BMA products in the synthesis of functionalized chromanes and chromenes in very good yields with high optical purity, which are very useful compounds in medicinal chemistry.     

DNA detection on lateral flow test strips: enhanced signal sensitivity using LNA-conjugated gold nanoparticles

A lateral flow test strip assay, enabling sensitive detection of DNA specific to the foodborne pathogen E. coli O157:H7, is described. The use of LNA-conjugated gold nanoparticle probes, along with signal amplification protocols, results in minimum detectable concentrations of ~0.4 nM.     

Deactivation of Escherichia coli with different volumes in drinking water using cold atmospheric plasma

This experimental study aimed to evaluate the potential of cold atmospheric plasma jet to deactivate Escherichia coli from drinking water. We studied the effect of the volume of water samples on the performance of plasma jet on deactivation of E. coli of 1, 500, 1,000, 1,500, and 2,000 cubic centimetres. The results of deactivation of E. coli in 500 and 1,000 cc water samples were the same as one cc of a water sample and we observed 8-log reduction of E. coli using 50 W. In 1,500 and 2,000 cc water samples at 8 min using a power of 50 W, 4.5 and 2.9 log reduction of E. coli was achieved and while we used 20 W, 2.5 and 1.8 log reduction of E. coli bacteria was performed. This indicated that the increasing volume of water above 1,500 cc caused the reduction of the efficiency of E. coli removal. Also, increasing power caused to increase E. coli removal efficiency. In addition, we monitored changes in pH values and temperature during experiments. Using 20 W, the temperature was increased (natural temperature of the water was 22 °C) 2 °C after 8 min while applying 50 W, the temperatures were raised 5 °C. pH of the water after 8 min in the 1,000 cc water sample, with an input power of 20 W, decreased from 7.1 to 5.5; while the input power was 50 W, pH changed from 7.1 to 4.3. With an increase in plasma irradiation time, the number of E. coli had a significant decrease per min while using in samples of 1 cc. After 8 min, we observed 4-log reductions of E. coli with the input power of 20 W and 8-log reduction of bacteria with the input power of 50 W. In 1,500 and 2,000 cc of water samples using plasma radiation for 8 min, 2.5 log and 1.8 log reduction of E. coli was achieved, respectively. This means that an increasing volume of water above 1,500 cc needs more power and time to deactivate E. coli from the water.     

Carbon-13 nuclear magnetic resonance spectra of substituted-s-triazolyl tetrazoles

The natural abundance carbon-13 nuclear magnetic resonance spectra of various 5-aryltetrazoles, 1-(5-aryltetrazol-2-ylacetyl)-4-phenyl thiosemicarbazides and 5-(5-aryltetrazol-2-ylmethyl)-4-phenyl-s-triazole-3-thiols were recorded using Fourier transform techniques. The chemical shifts of various carbon resonances have been assigned on the basis of chemical shift theory, the signal multiplicity observed in the single-frequency off-resonance decoupled (SFORD) spectra and comparison with the chemical shifts of the model compounds.     

On the probability of Magnus Carlsen reaching 2900

How likely is it that Magnus Carlsen will achieve his goal of a 2900 Elo rating? At what level of play does Magnus have a reasonable chance of reaching the 2900 goal? These two questions are of great current interest to Magnus and the chess community. The probabilistic properties of Elo's rating system are well known, and together with a Brownian motion model of rating evolution, we use simulation-based methods to address these questions. Our model assesses that Magnus has a 4.5% chance of reaching 2900 if he continues his 2020–2022 level of play. However, this increases dramatically to $80$% chance if he can repeat his hot streak performance of 2019 which is not an easy undertaking. The probabilities are intimately related to Elo's choice $K$-factor used for grandmaster chess play. Finally, we conclude with a discussion of the policy issues involved with the choice of $K$-factor.