2-Isonicotinoyl-N-phenyl­hydrazine­carbothio­amide dimethyl­formamide hemisolvate

The title compound, C13H12N4OS·0.5C3H7NO, contains four hydrazine mol­ecules and two solvent mol­ecules in the asymmetric unit. The dihedral angles between the pyridine and phenyl rings in the hydrazine mol­ecules are 67.51 (16), 68.28 (16), 81.36 (15) and 83.32 (15)°. In the crystal, the mol­ecules are linked by N—H⋯N, N—H⋯O and N—H⋯S hydrogen bonds

Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake?

<p>Abstract</p> <p>Background</p> <p>Polycyclic aromatic hydrocarbons (PAHs) are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment.</p> <p>Results</p> <p>The possibility that plant roots may take up phenanthrene (PHE), a representative of PAHs, via active process was investigated using intact wheat (<it>Triticum acstivnm L</it>.) seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 μM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent <it>K</it>_mof 23.7 μM and a <it>V</it>_maxof 208 nmol g^-1fresh weight h^-1, suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP) could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 μM). The contribution of active uptake to total absorption was almost 40% within PHE water solubility. PHE uptake by wheat roots caused an increase in external solution pH, implying that wheat roots take up PHE via a PHE/nH⁺symport system.</p> <p>Conclusion</p> <p>It is concluded that an active, carrier-mediated and energy-consuming influx process is involved in the uptake of PHE by plant roots.</p

Thermal Analysis and Characterization of Polystyrene Initiated by Benzoyl Peroxide

PresentationBased on the complexity of the polystyrene polymerization mechanism initiated by benzoyl peroxide (BPO), the thermal risk of the reaction process was estimated using thermal analysis and characterization. The polymerization process was thermally analysed using an adiabatic rate calorimeter and differential scanning calorimeter. The results demonstrated that the onset reaction temperature, adiabatic temperature rise, and maximum temperature of the synthesis reaction of BPO-initiated polymerization were lower than those of thermos initiated polymerization. Moreover, nuclear magnetic resonance imaging, gel permeation chromatography, and Fourier transform infrared spectrometry were used to characterize the polymerization products obtained under the two initiation conditions. The polystyrene obtained using the two initiation methods had the same hydrogen structure; however, their molecular weight and distribution uniformity differed considerably, and the BPO-initiated process was discovered to include the effects of the thermos initiated process. Moreover, the free radicals produced by BPO decomposition participated in the chain reaction of polystyrene polymerization, accelerated instantaneous grain growth, and promoted the formation of short- chain polystyrene. In summary, the BPO-initiated polymerization process exhibited the desired thermal safety characteristics and has potential for practical use