Isonitrile-responsive and bioorthogonally removable tetrazine protecting groups.

In vivo compatible reactions have a broad range of possible applications in chemical biology and the pharmaceutical sciences. Here we report tetrazines that can be removed by exposure to isonitriles under very mild conditions. Tetrazylmethyl derivatives are easily accessible protecting groups for amines and phenols. The isonitrile-induced removal is rapid and near-quantitative. Intriguingly, the deprotection is especially effective with (trimethylsilyl)methyl isocyanide, and serum albumin can catalyze the elimination under physiological conditions. NMR and computational studies revealed that an imine-tautomerization step is often rate limiting, and the unexpected cleavage of the Si-C bond accelerates this step in the case with (trimethylsilyl)methyl isocyanide. Tetrazylmethyl-removal is compatible with use on biomacromolecules, in cellular environments, and in living organisms as demonstrated by cytotoxicity experiments and fluorophore-release studies on proteins and in zebrafish embryos. By combining tetrazylmethyl derivatives with previously reported tetrazine-responsive 3-isocyanopropyl groups, it was possible to liberate two fluorophores in vertebrates from a single bioorthogonal reaction. This chemistry will open new opportunities towards applications involving multiplexed release schemes and is a valuable asset to the growing toolbox of bioorthogonal dissociative reactions

Synthesis of Bio-Dimethyl Ether Based on Carbon Dioxide-Enhanced Gasification of Biomass: Process Simulation Using Aspen Plus

YesProcess simulation of a single-step synthesis of DME based on CO2-enhanced gasification of rice straw was conducted using Aspen PlusTM. The process consists of gasification unit, heat recovery unit, gas purification unit, single-step DME synthesis, and DME separation unit. In the simulation, highly pure DME was produced by the control of CO2 concentration in syngas to a very low level prior to synthesis. A gasification system efficiency of 36.7% and CO2 emission of 1.31 kg/kg of DME were achieved. Bio-DME production based on CO2-enhanced gasification of biomass was found to be more cost-effective as it required 19.6% less biomass than that of DME production based on conventional biomass gasification. The performance and environmental benefits of the proposed process could be further improved by the utilization of unreacted gases and the handling of CO2 generated via incorporating poly-generation concept or carbon storage, which could also potentially improve process economics.Ningbo Bureau of Science and Technology; Innovation Team Scheme; Major R&D Programme; Provincial Innovation Team on the Commercialisation of SOx and NOx Removal Technologies; University of Nottingham Ningbo Chin

Optimizing seed rate for summer mungbean varieties

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from March to June, 2007 to investigate the effect of cultivar and seed rate on morphological characters, yield attributes and yield of summer mungbean. The experiment comprised four varieties viz., BINA moog2, BINA moog5, BINA moog6 and BINA moog7 and four seed rates viz. 30, 40, 50 and 60 kg ha-1. The experiment was laid out in a randomized complete block design with four replications. Results revealed that variety and seed rate had significant effect on the studied crop characters and yield. The variety BINA moog7 showed superiority in relation to plant height, number of branches and effective pods per plant, number of seeds pod-1 compared to other varieties, which resulted in the highest seed yield both per plant and per hectare. The plant height, stover yield and number of non-effective pods per plant increased with the increase in seed rate, while branch number, number of effective pods per plant, seeds per pod, 100-seed weight, as well as seed weight per plant decreased with increasing seed rate. The higher number of branches and effective pods per plant, number of seeds pod, 100-seed weight and seed yield per plant were recorded at the rate of 30 and 40 kg seeds ha-1 and the lowest values for the above parameters were observed at the rate of 60 kg seeds ha-1. But per unit area basis, the highest seed yield was recorded in 40 kg seeds ha-1 followed by 50 kg seeds ha-1 due to accommodation of higher number of plants. BINA moog7 interacted favorably with the seed rate of 30 kg ha-1 to produce the highest seed yield

A dimer of 4-(4-methoxyphenyl)-1,2,3,5-diselenadiazole

Sherpa Romeo green journalThe analysis of the title compound, C8H7N2OSe2, shows that its crystals are composed of weakly linked dimers, with intramolecular Se--Se distances of 2.343(3) and 2.345 (2)A,, intermolecular Se-.-Se distances of 3.193(3) and 3.316 (3) /k, and lateral Se...Se interactions of 3.514 (2) and 3.579 (3) A,.Ye

catena-Poly[[triphenyl­tin(IV)]-μ-2-[(3,5-di-tert-butyl-4-hydroxy­benz­yl)sulfan­yl]acetato-κ2 O:O′]

The title compound, [Sn(C6H5)3(C17H25O3S)]n, comprises two symmetry-independent five-coordinated triphenyl­tin mol­ecules which are linked by carboxyl­ate bridges into a polymeric chain. The SnIV atom is in a distorted trans-C3SnO2 trigonal-bipyramidal geometry. The presence of two bulky tert-butyl groups on the benzene ring prevents any hydrogen-bonding inter­actions involving the hydroxyl substituents

Preparation and x-ray structure of 4-N,N'-bis(trimethylsilyl)- amino-3,5-diisopropylphenylselenium trichloride

Open access article. Creative Commons Attribution 4.0 International License (CC BY 4.0) applies.The reaction of SeCU or SeCF with /V,/V’-bis(trimethylsilyl)-2,6-diisopropylaniline occurs not at the nitrogen atom but by electrophilic aromatic substitution at C-4 of the phenyl ring to give [(CH3)3Si]2NC6H2('Pr:)SeCl3, which crystallizes as the chloro-bridged dimer in the triclinic system, space group Pi, a - 10.2598(17), b = 13.665(3), c = 9.7838(10) A, a = 90.056(13), ß = 102.439(11), 7 = 70.922(14)°, V = 1262.3(4) A \Z = 1. The dimer contains an essentially planar CUSe^-Cl^SeCU unit, with trans apical (Me3SihNC6H2('Pr)2 groups, resulting in approximately square pyramidal geometry at Se. The bridging Se-Cl distances are unequal at 2.587(2) and 2.749(2) A.Ye

Differential Susceptibility of Human Peripheral Blood T Cells to Suppression by Environmental Levels of Sodium Arsenite and Monomethylarsonous Acid

Human exposure to arsenic in drinking water is known to contribute to many different health outcomes such as cancer, diabetes, and cardiopulmonary disease. Several epidemiological studies suggest that T cell function is also altered by drinking water arsenic exposure. However, it is unclear how individual responses differ to various levels of exposure to arsenic. Our laboratory has recently identified differential responses of human peripheral blood mononuclear cell (HPMBC) T cells as measured by polyclonal T cell activation by mitogens during sodium arsenite exposure. T cells from certain healthy individuals exposed to various concentrations (1–100 nM) of arsenite in vitro showed a dose-dependent suppression at these extremely low concentrations (∼0.1–10 ppb) of arsenite, whereas other individuals were not suppressed at low concentrations. In a series of more than 30 normal donors, two individuals were found to be sensitive to low concentration (10 nM equivalent ∼1 ppb drinking water exposure) to sodium arsenite-induced inhibition of T cell proliferation produced by phytohemagglutinin (PHA) and anti-CD3/anti-CD28. In an arsenite-susceptible individual, arsenite suppressed the activation of Th1 (Tbet) cells, and decreased the percentage of cells in the double positive Th17 (RORγt) and Treg (FoxP3) population. While the majority of normal blood donors tested were not susceptible to inhibition of proliferation at the 1–100 nM concentrations of As+3, it was found that all donors were sensitive to suppression by 100 nM monomethylarsonous acid (MMA+3), a key metabolite of arsenite. Thus, our studies demonstrate for the first time that low ppb-equivalent concentrations of As+3 are immunosuppressive to HPBMC T cells in some individuals, but that most donor HPBMC are sensitive to suppression by MMA+3 at environmentally relevant exposure levels

3,7-Di-tert-butyl-1,5,2,4,6,8-dithiatetrazocine

Sherpa Romeo green journalThe eight-membered ring in the title compound, C10HI8N4S2, lies about an inversion centre and is essentially planar with normal bond lengths and angles [mean C--S 1.569 (2) and mean C--N 1.326 (3)A].Ye

Bio-DME production based on conventional and CO2-enhanced gasification of biomass: A comparative study on exergy and environmental impacts

YesIn this study, a novel single-step synthesis of dimethyl ether (DME) based on CO2-enhanced biomass gasification was proposed and simulated using ASPEN PlusTM modelling. The exergetic and environmental evaluation was performed in comparison with a conventional system. It was found that the fuel energy efficiency, plant energy efficiency and plant exergetic efficiency of the CO2-enhanced system were better than those of the conventional system. The novel process produced 0.59 kg of DME per kg of gumwood with an overall plant energy efficiency of 65%, which were 28% and 5% higher than those of conventional systems, respectively. The overall exergetic efficiency of the CO2-enhanced system was also 7% higher. Exergetic analysis of each individual process unit in both the CO2-enhanced system and conventional systems showed that the largest loss occurred at gasification unit. However, the use of CO2 as gasifying agent resulted in a reduced loss at gasifier by 15%, indicating another advantage of the proposed system. In addition, the LCA analysis showed that the use of CO2 as gasifying agent could also result in less 21 environmental impacts compared with conventional systems, which subsequently made the CO2-22 enhanced system a promising option for a more environmental friendly synthesis of bio-DME.Part of this work is sponsored by Ningbo Bureau of Science and Technology under its Innovation Team Scheme (2012B82011) and Major R&D Programme (2012B10042)