HIV incidence and recreational drug use among men who have sex with men aged 18-24 years in Tianjin, China: a retrospective cohort study.

Background: Recreational drug use has been identified as a significant risk factor for the transmission of human immunodeficiency virus (HIV). This behavior is particularly prevalent among young men who have sex with men (YMSM). However, limited research has been conducted to investigate the correlation between recreational drug use and HIV incidence within this population.

(E)-N'-[1-(4-Bromo-phen-yl)ethyl-idene]benzohydrazide.

The asymmetric unit of the title compound, C(15)H(13)BrN(2)O, contains two independent mol-ecules with different conformations; the two aromatic rings form dihedral angles of 32.4 (4) and 27.5 (4)° in the two mol-ecules.

(E)-N'-(4-Methoxy-benzyl-idene)benzohydrazide.

In the title mol-ecule, C(15)H(14)N(2)O(2), the dihedral angle between the benzene rings is 5.93 (17)°. In the crystal, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains propagating in [010].

catena-Poly[[[2,6-bis-(pyrazol-1-yl-κN)pyridine-κN](nitrato-κO,O')cadmium(II)]-μ-thio-cyanato-κN:S].

In the title crystal structure, [Cd(NCS)(NO(3))(C(11)H(9)N(5))](n), the unique Cd(II) ion is coordinated in a distorted penta-gonal-bipyramidal environment. The axial thio-cyanate ligands act in a μ(1,3)-bridging mode to connect symmetry-related Cd(II) ions into one-dimensional chains along [010]. In addition, there are inter-molecular C-H⋯O contacts between chains.

Dichlorido(2,6-dipyrazol-1-ylpyridine)zinc(II).

In the title complex, [ZnCl(2)(C(11)H(9)N(5))], the Zn(II) ion assumes a distorted trigonal-bipyramidal ZnN(3)Cl(2) coordination geometry [Zn-N = 2.1397 (16)-2.2117 (17) Å, Zn-Cl = 2.

Diaqua-bis[2-(2-pyridylmeth-oxy)pyrazine-κN]bis-(thio-cyanato-κN)cobalt(II).

In the title complex, [Co(NCS)(2)(C(10)H(9)N(3)O)(2)(H(2)O)(2)], the Co(II) ion is located on a crystallographic twofold rotation axis and is in a slightly distorted octa-hedral CoN(4)O(2) coordination environment. The dihedral angle between the pyridine and pyrazine rings is 85.86 (10)°.

catena-Poly[[bis-[2-chloro-6-(1H-1,2,4-triazol-1-yl-κN)pyridine]cadmium(II)]-di-μ-thio-cyanato-κN:S;κS:N]: a one-dimensional coordination polymer.

In the crystal structure of the title complex, [Cd(NCS)(2)(C(7)H(5)ClN(4))(2)](n), the Cd(II) atom lies on a crystallographic inversion center and assumes a distorted octa-hedral geometry. The 2-chloro-6-(1H-1,2,4-triazol-1-yl)pyridine mol-ecule acts as a terminal ligand. The thio-cyanate ligands function as μ(1,3)-bridging units connecting adjacent Cd(II) atoms with a separation of 5.