N′-(3-Hy­droxy­benzyl­idene)-4-nitro­benzohydrazide

The title mol­ecule, C14H11N3O4, is approximately planar, with an inter­planar angle between the two benzene rings of 5.8 (2)°. In the crystal, four mol­ecules are linked by an R 4 4(12) motif with pairs of strong O—H⋯O and N—H⋯O hydrogen bonds. The motif is situated about the crystallographic centres of symmetry and it is composed of two pairs of parallel mol­ecules. This quadruplet of mol­ecules is further extended by symmetry-equivalent hydrogen bonds to form layers parallel to the (10) plane. In addition to the hydrogen bonds, there is also a weak π–π inter­action between the benzene rings

N′-(4-Hy­droxy­benzyl­idene)-4-nitro­benzohydrazide

The title compound, C14H11N3O4, was prepared by the reaction of 4-nitro­benzohydrazide with 4-hy­droxy­benz­alde­hyde. The whole mol­ecule of the compound is approximately planar, with a mean deviation from the least-squares plane through all the non-H atoms of 0.050 (2) Å; the dihedral angle between the two benzene rings is 2.0 (2)°. In the crystal, the benzohydrazide mol­ecules are linked through inter­molecular O—H⋯O and N—H⋯O hydrogen bonds, forming layers in the bc plane

A Retrospective Cohort Study Comparing Stroke Recurrence Rate in Ischemic Stroke Patients With and Without Acupuncture Treatment.

Little was known about the effects of acupuncture on stroke recurrence. The aim of this study is to investigate whether ischemic stroke patients receiving acupuncture treatment have a decreased risk of stroke recurrence. A retrospective cohort study of 30,058 newly diagnosed cases of ischemic stroke in 2000 to 2004 was conducted based on the claims of Taiwan National Health Insurance Research Database. The use of acupuncture treatment and stroke recurrence were identified during the follow-up period from 2000 to 2009. This study compared the risk of stroke recurrence between ischemic stroke cohorts with and without acupuncture treatment by calculating adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of acupuncture associated with stroke recurrence in the Cox proportional hazard model. The stroke recurrence rate per 1000 person-years decreased from 71.4 without to 69.9 with acupuncture treatment (P < 0.001). Acupuncture treatment was associated with reduced risk of stroke recurrence (HR 0.88; 95% CI 0.84-0.91). The acupuncture effect was noted in patients with or without medical treatment for stroke prevention but its impact decreased with aging of stroke patients. Compared with stroke patients without acupuncture treatment and medication therapy, the hazard ratios of stroke recurrence for those had medication therapy only, acupuncture only, and both were 0.42 (95% CI 0.38-0.46), 0.50 (95% CI 0.43-0.57), and 0.39 (95% CI 0.35-0.43), respectively. This study raises the possibility that acupuncture might be effective in lowering stroke recurrence rate even in those on medications for stroke prevention. Results suggest the need of prospective sham-controlled and randomized trials to establish the efficacy of acupuncture in preventing stroke

A Unique Seasonal Pattern in Phytoplankton Biomass in Low-Latitude Waters in the South China Sea

A distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth integrated chlorophyll-a and primary production were elevated to 0.3 mg/m3, ~35 mg/m2 and 300 mg-C/m2/d, respectively, in the winter but stayed low, at 0.1 mg/m3, ~15 mg/m2 and 110 mg-C/m2/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became readily detectable in the winter. The elevation of phytoplankton biomass coincided approximately with the lowest sea surface temperature and the highest wind speed in the year. Only the combined effect of convective overturn by surface cooling and wind-induced mixing could have enhanced vertical mixing sufficiently to make the nutrients in the upper nutricline available for photosynthetic activities and accounted for the higher biomass in the winter

(E)-N′-(2,4-Dichloro­benzyl­idene)-3-nitro­benzohydrazide

The title compound, C14H9Cl2N3O3, was prepared by the reaction of 3-nitro­benzohydrazide with 2,4-dichloro­benzalde­hyde. The mol­ecule adopts an E configuration about the C=N bond. The dihedral angle between the two benzene rings is 4.6 (2)°. In the crystal, the hydrazone mol­ecules are linked through inter­molecular N—H⋯O hydrogen bonds, forming chains along the c axis

(E)-N′-(3-Hy­droxy­benzyl­idene)-3-nitro­benzohydrazide

The title compound, C14H11N3O4, was prepared by the reaction of 3-nitro­benzohydrazide with 3-hy­droxy­benzalde­hyde. The mol­ecule adopts an E configuration about the C=N bond. The dihedral angle between the two benzene rings is 32.3 (2)°. In the crystal, the mol­ecules are linked through inter­molecular N—H⋯O, O—H⋯N, and O—H⋯O hydrogen bonds, forming chains in the a-axis direction