n-Si/SiGe quantum cascade structures for THz emission

In this work we report on modelling the electron transport in n-Si/SiGe structures. The electronic structure is calculated within the effective-mass complex-energy framework, separately for perpendicular (Xz) and in-plane (Xxy) valleys, the degeneracy of which is lifted by strain, and additionally by size quantization. The transport is described via scattering between quantized states, using the rate equations approach and tight-binding expansion, taking the coupling with two nearest-neighbour periods. The acoustic phonon, optical phonon, alloy and interface roughness scattering are taken in the model. The calculated U/I dependence and gain profiles are presented for a couple of QC structures

α-Amylase inhibitory property, antioxidant activity and toxicological study of Salvia chloroleuca

Abstract Background and objectives: Salvia chloroleuca Rech. f. & Allen., is an endemic species growing wildly in north east and center parts of Iran but there is no information about its safety. To provide information about the safety of the species, we evaluated its acute and sub chronic toxicity in rats. Methods: In acute toxicity study, the aqueous methanol (80%) extract at a single dose of 2000 mg/kg/day was administered orally to male and female rats and signs of toxicity two weeks after administration were observed. For the subchronic toxicity test, the extract at doses of 250, 500 and 1000 mg/kg/day were orally administered to the rats of both sexes for 45 days. Mortality, clinical signs of toxicity and body weight changes were monitored during the study. Moreover, α-amylase enzyme inhibition, total phenol content, and antioxidant (DPPH and FRAP assays) activity of different fractions of aerial part were evaluated. Results: The methanol and aqueous methanol (80%) extracts showed α-amylase enzyme inhibition with IC 50 values 14.03 mg/mL and 18.05 mg/mL, respectively. The IC 50 value for ethyl acetate, methanol and aqueous methanol (80%) extracts in radical scavenging assay were calculated as 288.83, 97.93, and 108.02 μg/mL, respectively. Among all extracts, methanol (228.4±12.05) demonstrated the highest FRAP value, followed by methanol (80%) extract (220.4±8.08) and ethyl acetate extract (156.4±10.06). In acute toxicity and subchronic study, neither mortality nor changes in behavior or any other parameter were observed. Conclusion: Our findings indicate potent in vitro α-amylase and antioxidant activity of S. chloroleuca and propose its potential as an anti-diabetic agent for treatment of noninsulin-dependent diabetes mellitus (NIDDM) patients

Enhancement the removal capacity of heavy metals from aqueous solution using different aquatic organisms

151-162The Eichhornia sp had high ability for bioremoval of Pb and Cd (97.15 and 97.48%) during 15 min with some ultrastructure changes of the leaf such as, ruptured or disappeared plasma membrane, swollen mitochondria and malformation chloroplast and some anatomical studies; thickness of upper epidermis and mesophyll decreased with presences number of raphide crystals in treated leaf but it not found in untreated plants. It was noticed that treated with Pb was more effect on histological leaf than treated with Cd. While, Gelidium pectinatum had highest efficiency for removal of Cd but during 0.5 hr. The bioremoval efficiency of lead by Gelidium pectinatum increased with Epichlorohydrin 1 from 28.84 to 90.18 % during 240 min contact time and from 77.34 in raw (untreated) algae to 99.58% in case of cadmium during the same contact time

Imaging of hydrothermal altered zones in Wadi Al-Bana, in southern Yemen, using remote sensing techniques and very low frequency–electromagnetic data

© 2019, Saudi Society for Geosciences. Economic mineralization and hydrothermally altered zones are areas of great economic interests. This study focusses on hydrothermal altered zones of high mineralization potentials in Wadi Al-Bana, in southern Yemen. An azimuthal very low frequency–electromagnetic (AVLF-EM) data acquisition was conducted in search for mineralization in the study area. The study integrated observations from geophysical field data with others extracted from object-oriented principal component analysis (PCA) to better map and understand mineralization in the investigated area. This technique was applied to two data sets, ASTER and Landsat 8 Operational Land Imager (OLI) imagery. The results of PCA revealed high accuracy in detecting alteration minerals and for mapping zones of high concentration of these minerals. The PCA-based distribution of selected alteration zones correlated spatially with high conductivity anomalies in the subsurface that were detected by VLF measurements. Finally, a GIS model was built and successfully utilized to categorize the resulted altered zones, into three levels. [Figure not available: see fulltext.]

Prostate Cancer Cell Lines under Hypoxia Exhibit Greater Stem-Like Properties

Hypoxia is an important environmental change in many cancers. Hypoxic niches can be occupied by cancer stem/progenitor-like cells that are associated with tumor progression and resistance to radiotherapy and chemotherapy. However, it has not yet been fully elucidated how hypoxia influences the stem-like properties of prostate cancer cells. In this report, we investigated the effects of hypoxia on human prostate cancer cell lines, PC-3 and DU145. In comparison to normoxia (20% O2), 7% O2 induced higher expressions of HIF-1α and HIF-2α, which were associated with upregulation of Oct3/4 and Nanog; 1% O2 induced even greater levels of these factors. The upregulated NANOG mRNA expression in hypoxia was confirmed to be predominantly retrogene NANOGP8. Similar growth rates were observed for cells cultivated under hypoxic and normoxic conditions for 48 hours; however, the colony formation assay revealed that 48 hours of hypoxic pretreatment resulted in the formation of more colonies. Treatment with 1% O2 also extended the G0/G1 stage, resulting in more side population cells, and induced CD44 and ABCG2 expressions. Hypoxia also increased the number of cells positive for ABCG2 expression, which were predominantly found to be CD44bright cells. Correspondingly, the sorted CD44bright cells expressed higher levels of ABCG2, Oct3/4, and Nanog than CD44dim cells, and hypoxic pretreatment significantly increased the expressions of these factors. CD44bright cells under normoxia formed significantly more colonies and spheres compared with the CD44dim cells, and hypoxic pretreatment even increased this effect. Our data indicate that prostate cancer cells under hypoxia possess greater stem-like properties

Peridotites from the Khoy Ophiolitic Complex, NW Iran : evidence of mantle dynamics in a supra-subduction-zone context

The Khoy Ophiolitic Complex as a part of the Tethyan ophiolites is exposed in the northwestern part of the Iranian-Azerbaijan province, extending to the Anatolian ophiolites in southeastern Turkey. Petrography, geochemistry and microstructural studies of the residual mantle sequence in the Khoy Ophiolitic Complex provide important information about the degree of partial melting and deformation in the oceanic mantle lithosphere. Ultramafic tectonites dominantly composed of lherzolite and clinopyroxene-bearing harzburgite (TiO₂ = 0.012-0.024 wt.%; Al₂O₃ = 1.36-1.81 wt.%). Chondrite-normalized rare-earth-element patterns are characteristically U-shaped. These peridotites can be divided into two types: (1) type 1 peridotites with Al-rich spinels (Cr number of 0.16-0.26, and Mg number of 0.64-0.76), resembling the fertile abyssal peridotites, supposed to have originated as the residue from 20% partial melting, followed by segregation of basaltic magmas. Microstructural fabrics of olivine grains in peridotites highlight a sequence of dislocation creep on the (0 1 0) [1 0 0] slip system, plus subsidiary slip along the (0 0 1) [1 0 0] slip system. These systems, as well as coarse and fine-grained porphyroclastic textures, indicate deformation at high temperatures of ~1000–1250 ℃. The observed subsidiary (0 0 1) [1 0 0] slip system is considered to have been triggered by elevated H₂O activity, and that deformation phases took place in a wet subduction-related environment. The geochemical and microstructural data suggest that the mantle sequence of the Khoy Ophiolitic Complex is consistent with a supra-subduction-zone environment in relation to a slow-spreading back-arc basin.16 page(s