(μ-Acetato){μ-1,3-bis[2-(2-oxidobenzylideneamino)ethyl]-2-(2-oxidophenyl)-1,3-imidazolidine}dizinc(II) ethanol disolvate dihydrate

In the title binuclear compound, [Zn2(C27H27N4O3)(C2H3O2)]·2CH3CH2OH·2H2O, both Zn cations adopt distorted ZnO3N2 trigonal-bipyramidal geometries with one N atom in a axial site and one N atom in an equatorial site, arising from coordination by the N,N,N,N,O,O,O-hepta­dentate ligand and a bridging acetate ion. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the component units into a three-dimensional network. Two short C—H⋯O contacts are also seen

Two halosesquiterpenes from Laurencia composita

Two new chamigrane sesquiterpenes, yicterpenes A (1) and B (2) each with an unprecedented halogenation at C-9 and a hemiketal unit at C-10, were isolated from the marine red algaLaurencia composita. The structures and absolute configurations of them were identified by NMR, ECD, and mass spectrometric methods as well as quantum chemical calculations. Compound 1 with a chlorination at C-9 was more active against some tested marine-derived organisms than 2 with a bromination at C-9.  Two new chamigrane sesquiterpenes, yicterpenes A (1) and B (2) each with an unprecedented halogenation at C-9 and a hemiketal unit at C-10, were isolated from the marine red alga Laurencia composita. The structures and absolute configurations of them were identified by NMR, ECD, and mass spectrometric methods as well as quantum chemical calculations. Compound 1 with a chlorination at C-9 was more active against some tested marine-derived organisms than 2 with a bromination at C-9

Sesquiterpenes from the marine red alga Laurencia composita.

Four new chamigrane derivatives, laurecomin A (1). laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5), and three known halogenated structures, deoxyprepacifenol (6), 1-bromoselin-4(14),11-diene (7), and 9-bromoselin-4(14).11-diene (8), were isolated from the marine red alga Laurencia cornposita collected from Pingtan Island, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 2 was active against both brine shrimp and fungus Colletotrichum lagenarium. (C) 2012 Elsevier B.V. All rights reserved.Four new chamigrane derivatives, laurecomin A (1). laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5), and three known halogenated structures, deoxyprepacifenol (6), 1-bromoselin-4(14),11-diene (7), and 9-bromoselin-4(14).11-diene (8), were isolated from the marine red alga Laurencia cornposita collected from Pingtan Island, China. The structures of these compounds were unambiguously established by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 2 was active against both brine shrimp and fungus Colletotrichum lagenarium. (C) 2012 Elsevier B.V. All rights reserved

Time and spatial distribution of multidrug-resistant tuberculosis among Chinese people, 1981–2006: a systematic review

SummaryObjectivesWe aimed to investigate trends in the prevalence of multidrug-resistant tuberculosis (MDR-TB) among Chinese people from first report to 2006, and to detect the high prevalence regions in order to guide control efforts.Materials and methodsThe CBM, VIP, CNKI, and MEDLINE databases were searched through both keywords and subject headings. The literature was screened, and two investigators assessed the quality and extracted the data. Trends in MDR-TB prevalence in three groups – primary, acquired, and combined MDR-TB – were examined separately, using the Cochran–Armitage trend test. Differences were tested with the Kruskal–Wallis test. High prevalence provinces were explored through comparison of the 95% confidence interval (95% CI) with the national average level.ResultsOverall 169 studies were included, with 165 in Chinese and four in English. One hundred and sixteen studies concerned primary MDR-TB, 103 acquired MDR-TB, and 130 combined MDR-TB, with total positive Mycobacterium tuberculosis (MTB) isolates of 110 076, 25 187, and 150 233, respectively. The prevalences of MDR-TB in the three groups in 2005 were 2.64-, 6.20-, and 3.84-times that of 1985, respectively, all showing an upward trend (p<0.05). The prevalences among the three groups were significantly different (p<0.05), with acquired drug resistance (27.5%, 95% CI 26.9–28.1%) much higher than primary drug resistance (4.3%, 95% CI 4.2–4.4%), and combined resistance (9.9%, 95% CI 9.8–10.1%) in between. The top three prevalence regions for primary, acquired, and combined MDR-TB were distributed in the zone from the northeast to the southwest of China, with Hebei, Tibet, and Shanxi having an extremely high prevalence.ConclusionsThe prevalence of MDR-TB among the Chinese people has shown an upward trend since 1985. It is necessary to continue to monitor this trend in China. Special attention should be paid to provinces distributed in the zone from the northeast to the southwest of China for MDR-TB surveillance, research, and control

Imidazolium trans-bis­(imino­diacetato-κ3 O,N,O′)cobaltate(III)

In the title compound, (C3H5N2)[Co(C4H5NO4)2], the cation and anion are located on a twofold rotation axis and inversion center, respectively. Inter­molecular N—H⋯O hydrogen bonds link the cations and anions into layers parallel to the ab plane. The crystal packing also exhibits weak C—H⋯O hydrogen bonds, including bifurcated hydrogen bonds, and C=O⋯π inter­actions

Strangeon matter and strangeon stars in a linked bag model

Inspired by various astrophysical phenomenons, it was suggested that pulsar-like compact stars may in fact be strangeon stars, comprised entirely of strangeons (quark-clusters with three-light-flavor symmetry) and a small amount of electrons. To examine such possibilities, in this work we propose a linked bag model, which can be adopted for strong condensed matter in both 2-flavoured (nucleons) and 3-flavoured (hyperons, strangeons, etc.) scenarios. The model parameters are calibrated to reproduce the saturation properties of nuclear matter, which are later applied to hyperonic matter and strangeon matter. The obtained energy per baryon of strangeon matter is reduced if we adopt larger quark numbers inside a strangeon, which stiffens the equation of state and consequently increases the maximum mass of strangeon stars. In a large parameter space, the maximum mass and tidal deformability of strangeon stars predicted in the linked bag model are consistent with the current astrophysical constraints. It is found that the maximum mass of strangeon stars can be as large as $\sim 2.5M_\odot$, while the tidal deformability of a $1.4M_\odot$ strangeon star lies in the range of $180\lesssim \Lambda_{1.4} \lesssim 340$. More refined theoretical efforts as well as observational tests to these results are necessary in the future