Larvicidal activity of Illicium difengpi BN Chang (Schisandraceae) Stem Bark and its Constituent Compounds against Aedes aegypti L

Purpose: To determine the larvicidal activity of the essential oil derived from Illicium difengpi B.N. Chang stem bark (Schisandraceae) and its major constituents against the larvae of Aedes aegypti L.Methods: Essential oil of I. difengpi stem bark was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mas spectrometry (GC-MS). The activity of the essential oil and its major constituents was evaluated, using World Health Organization (WHO) procedures, against the fourth instar larvae of A. aegypti for 24 h, and larval mortalities recorded at essential oil/compound concentrations ranging from 6.0 - 200 μg/mL.Results: A total of 36 components of the essential oil of I. difengpi were identified. The principal compounds are safrole (18.21 %), linalool (13.47 %), 1,8-cineole (12.84 %), and myristicin (8.06 %) followed by α-terpineol (4.77 %), β-pinene (4.45 %) and 4-terpineol (4.38 %). The essential oil exhibited larvicidal activity against A. aegypti with LC50 (median lethal concentration) of 31.68 μg/mL. The major constituents, myristicin, safrole, and 1, 8-cineole, exhibited LC50 of 15.26, 39.45, and 72.18 μg/mL, respectively.Conclusion: The findings obtained indicate that the essential oil of I. difengpi and its major constituents have potentials for use in the control of A. aegypti larvae and may therefore be useful in the search for newer, safer and more effective natural compounds as larvicides.Keywords: Illicium difengpi, Aedes aegypti, Larvicidal activity, Myristicin, Safrole, 1,8-Cineole, Linaloo

A dual cube hashing scheme for solving LPP integrity problem

In digital forensics, data stored in a hard disk usually contains valuable evidence. Preserving the integrity of the data in the hard disk is a critical issue. A single hash value for the whole hard disk is not appropriate as the investigation may take a long time and latent sector errors (LSEs) (bad sectors due to media imperfection, for example) which cause a sector suddenly unreadable will make the hash value inconsistent. On the other hand, using a hash per sector may need to store a lot of hash values. Previous research has been conducted to use fewer hash values, but can resist some of LSEs to decrease the number of unverifiable sectors even if there are LSEs. This integrity problem is more complicated in the presence of Legal Professional Privileged (LPP) data inside a seized hard disk in digital forensic as the hard disk has to be cloned once seized and the original hard disk will be sealed after cloning. Hash values need to be computed during this cloning process. However, the cloned copy will be returned to the suspect for the deletion of LPP data before the investigator can work on the sanitized copy. Thus, the integrity of unmodified sectors has to be verified using the hash values computed based on the original hard disk. This paper found that existing schemes are not good enough to solve the integrity problem in the presence of both LSEs and deletion of LPP data. We then propose the idea of a "Dual Cube" hashing scheme to solve the problem. The experiments show the proposed scheme performs better than the previous schemes and fits easily into the digital forensic procedure. © 2011 IEEE.published_or_final_versionThe 6th International Workshop on Systematic Approaches to Digital Forensic Engineering In conjunction with the IEEE Security and Privacy Symposium (IEEE/SADFE 2011), Oakland, CA., 26 May 2011. In IEEE/SADFE Proceedings, 2011, p. 1-

Multivalency-Driven Formation of Te-Based Monolayer Materials: A Combined First-Principles and Experimental study

published_or_final_versio

Temporal and Spatial Profiling of Root Growth Revealed Novel Response of Maize Roots under Various Nitrogen Supplies in the Field

A challenge for Chinese agriculture is to limit the overapplication of nitrogen (N) without reducing grain yield. Roots take up N and participate in N assimilation, facilitating dry matter accumulation in grains. However, little is known about how the root system in soil profile responds to various N supplies. In the present study, N uptake, temporal and spatial distributions of maize roots, and soil mineral N (Nmin) were thoroughly studied under field conditions in three consecutive years. The results showed that in spite of transient stimulation of growth of early initiated nodal roots, N deficiency completely suppressed growth of the later-initiated nodal roots and accelerated root death, causing an early decrease in the total root length at the rapid vegetative growth stage of maize plants. Early N excess, deficiency, or delayed N topdressing reduced plant N content, resulting in a significant decrease in dry matter accumulation and grain yield. Notably, N overapplication led to N leaching that stimulated root growth in the 40–50 cm soil layer. It was concluded that the temporal and spatial growth patterns of maize roots were controlled by shoot growth and local soil Nmin, respectively. Improving N management involves not only controlling the total amount of chemical N fertilizer applied, but also synchronizing crop N demand and soil N supply by split N applications

Large-scale Synthesis of β-SiC Nanochains and Their Raman/Photoluminescence Properties

Although the SiC/SiO2 nanochain heterojunction has been synthesized, the chained homogeneous nanostructure of SiC has not been reported before. Herein, the novel β-SiC nanochains are synthesized assisted by the AAO template. The characterized results demonstrate that the nanostructures are constructed by spheres of 25–30 nm and conjoint wires of 15–20 nm in diameters. Raman and photoluminescence measurements are used to explore the unique optical properties. A speed-alternating vapor–solid (SA-VS) growth mechanism is proposed to interpret the formation of this typical nanochains. The achieved nanochains enrich the species of one-dimensional (1D) nanostructures and may hold great potential applications in nanotechnology

The VEGF -634G>C promoter polymorphism is associated with risk of gastric cancer

<p>Abstract</p> <p>Background</p> <p>Both TGF-β1 and VEGF play a critic role in the multiple-step process of tumorgenesis of gastric cancer. Single nucleotide polymorphisms (SNPs) of the <it>TGFB1 </it>and <it>VEGF </it>genes have been associated with risk and progression of many cancers. In this study, we investigated the association between potentially functional SNPs of these two genes and risk of gastric cancer in a US population.</p> <p>Methods</p> <p>The risk associated with genotypes and haplotypes of four <it>TGFB1 </it>SNPs and four <it>VEGF </it>SNPs were determined by multivariate logistic regression analysis in 171 patients with gastric cancer and 353 cancer-free controls frequency-matched by age, sex and ethnicity.</p> <p>Results</p> <p>Compared with the <it>VEGF</it>-634GG genotype, the -634CG genotype and the combined -634CG+CC genotypes were associated with a significantly elevated risk of gastric cancer (adjusted OR = 1.88, 95% CI = 1.24-2.86 and adjusted OR = 1.56, 95% CI = 1.07-2.27, respectively). However, none of other <it>TGFB1 </it>and <it>VEGF </it>SNPs was associated with risk of gastric cancer.</p> <p>Conclusion</p> <p>Our data suggested that the <it>VEGF</it>-634G>C SNP may be a marker for susceptibility to gastric cancer, and this finding needs to be validated in larger studies.</p

Partial oxidation of methane to syngas over Rh/SiO2 catalyst

Partial oxidation of methane (POM) over Rh/SiO2 Catalyst was investigated by using several techniques, such as TPD, TPR, TPSR and trapping agent, combined with MS. At the beginning of POM reaction, only gaseous CO2 can be detected over the catalyst. With the increase in space velocity, the conversion of CH4 and the selectivity for CO and H-2 increase, while the selectivity for CO2 decreases. During the pulse reaction with CH4 as reactant, over the catalyst prereduced at 700 degreesC, CO and H-2 can be detected as main products with trace C2H6 and C2H4. When the catalyst is exposed to CH4-He, there are two kinds of carbonaceous species formed, and they are designated CHalpha and CHbeta, as identified by their hydrogenation temperature of 210 similar to 260 degreesC and 450 similar to 800 degreesC, respectively. The CHalpha is assigned to H-rich form and the CHbeta is assigned to H-deficient form. When the catalyst is exposed to CH4-O-2-He, the carbonaceous species are mainly CHalpha with trace CHbeta. The two kinds of carbonaceous species may play different roles in POM reaction. The CHbeta accumulated during CH4 activation is the possible cause for catalyst deactivation, and the CHalpha may be responsible for CO formation. The CHx may be the intermediate of POM reaction. In the trapping reaction, a series of ions with M-r/z = 2 similar to 46 have been detected at 300 similar to 600 degreesC. The CHxO (x = 1 similar to 3) may be the O-containing intermediate of POM reaction. Based on the above results, the POM mechanism has been proposed. Over the reduced catalyst, CH4 is firstly dissociated, forming the surface species CHx. By reacting with the active species OH-, the CHalpha is oxidized to O-containing intermediate, CHxO, which can be dehydrogenated to give the adsorbed and gaseous CO

Synthesis, Magnetic Anisotropy and Optical Properties of Preferred Oriented Zinc Ferrite Nanowire Arrays

Preferred oriented ZnFe2O4 nanowire arrays with an average diameter of 16 nm were fabricated by post-annealing of ZnFe2 nanowires within anodic aluminum oxide templates in atmosphere. Selected area electron diffraction and X-ray diffraction exhibit that the nanowires are in cubic spinel-type structure with a [110] preferred crystallite orientation. Magnetic measurement indicates that the as-prepared ZnFe2O4 nanowire arrays reveal uniaxial magnetic anisotropy, and the easy magnetization direction is parallel to the axis of nanowire. The optical properties show the ZnFe2O4 nanowire arrays give out 370–520 nm blue-violet light, and their UV absorption edge is around 700 nm. The estimated values of direct and indirect band gaps for the nanowires are 2.23 and 1.73 eV, respectively

Characterization and Separation Performance of a Novel Polyethersulfone Membrane Blended with Acacia Gum

Novel polyethersulfone (PES) membranes blended with 0.1–3.0 wt. % of Acacia gum (AG) as a pore-former and antifouling agent were fabricated using phase inversion technique. The effect of AG on the pore-size, porosity, surface morphology, surface charge, hydrophilicity, and mechanical properties of PES/AG membranes was studied by scanning electron microscopy (SEM), Raman spectroscopy, contact angle and zeta potential measurements. The antifouling -properties of PES/AG membranes were evaluated using Escherichia coli bacteria and bovine serum albumine (BSA). The use of AG as an additive to PES membranes was found to increase the surface charge, hydrophilicity (by 20%), porosity (by 77%) and permeate flux (by about 130%). Moreover, PES/AG membranes demonstrated higher antifouling and tensile stress (by 31%) when compared to pure PES membranes. It was shown that the prepared PES/AG membranes efficiently removed lead ions from aqueous solutions. Both the sieving mechanism of the membrane and chelation of lead with AG macromolecules incorporated in the membrane matrix contributed to lead removal. The obtained results indicated that AG can be used as a novel pore-former, hydrophilizing and antifouling agent, as well as an enhancer to the mechanical and rejection properties of the PES membranes