Evidence of improvement in thermoelectric parameters of n-type Bi2Te3/graphite nanocomposite

Improvement of thermoelectric parameters is reported with graphite incorporation in n-type Bi2Te3/graphite nanocomposite system. In-depth thermoelectric properties of nanostructured Bi2Te3/graphite composites are probed both microscopically and macroscopically using X-ray diffraction, Raman spectroscopy, inelastic neutron scattering and measurement of the temperature dependence of thermal conductivity , Seebeck coefficient S, resistivity ρ, and carrier concentration nH. Raman spectroscopic analysis confirms that graphite introduces defects and disorder in the system. Graphite addition induces a large (17%) decrease of , originating from a strong phonon scattering effect. A low lattice thermal conductivities L, value of 0.77 Wm-1K-1, approaching the min value, estimated using the Cahill-Pohl model, is reported for Bi2Te3+1 wt% graphite sample. Graphite dispersion alters the low energy inelastic neutron scattering spectrum providing evidence for modification of the Bi2Te3 Phonon Density of States (PDOS). Improvement of the other thermoelectric parameters, viz., Seebeck Coefficient and resistivity, is also reported. Theoretical modeling of electrical and thermal transport parameters is carried out and a plausible explanation of the underlying transport mechanism is provided assuming a simple model of ballistic electron transport in 1D contact channels with two different energies

Effects of Payena dasyphylla (Miq.) on hyaluronidase enzyme activity and metalloproteinases protein expressions in interleukin-1beta stimulated human chondrocytes cells

Background: Hyaluronidases have been found as the target enzymes in the development of osteoarthritis (OA) disease. While there is still no curative treatment for this disease, recent studies on the treatment of OA were focused on the effectiveness of natural products which are expected to improve the symptoms with minimal side effects. The aim of this study was to screen selected Malaysian plants on their anti-hyaluronidase activity as well as to evaluate the active plant and its derived fractions on its potential anti-arthritic and antioxidant activities.Methods: A total of 20 methanolic crude extracts (bark and leaf) from ten different plants were screened using a colorimetric hyaluronidase enzymatic assay. The active plant extract (Payena dasyphylla) was then studied for its hyaluronidase inhibitory activity in the interleukin-1β (IL-1β) stimulated human chondrocytes cell line (NHAC-kn) using zymography method. The Payena dasyphylla methanolic bark extract was then fractionated into several fractions in where the ethyl acetate (EA) fraction was evaluated for its inhibitory effects on the HYAL1 and HYAL2 gene expressions using reverse transcription-polymerase chain reaction (RT-PCR) technique. While the MMP-3 and MMP-13 protein expressions were evaluated using western blot method. The phenolic and flavonoid contents of the three fractions as well as the antioxidant property of the EA fraction were also evaluated.Results: Bark extract of Payena dasyphylla (100 μg/ml) showed the highest inhibitory activity against bovine testicular hyaluronidase with 91.63%. The plant extract also inhibited hyaluronidase expression in the cultured human chondrocyte cells in response to IL-1β (100 ng/ml). Similarly, treatment with Payena dasyphylla ethyl acetate (EA) fraction (100 μg/ml) inhibited the HYAL1 and HYAL2 mRNA gene expressions as well as MMP-3 and MMP-13 protein expression in a dose dependent manner. Payena dasyphylla EA fraction has demonstrated the highest amount of phenolic and flavonoid content with 168.62 ± 10.93 mg GAE/g and 95.96 ± 2.96 mg RE/g respectively as compared to water and hexane fractions. In addition, the Payena dasyphylla EA fraction showed strong antioxidant activity with IC50 value of 11.64 ± 1.69 μg/mL.Conclusion: These findings have shown that Payena dasyphylla might contained potential phenolic compounds that inhibiting the key enzyme in osteoarthritis development, which is the hyaluronidase enzyme through interruption of HYAL1 and HYAL1 gene expressions. The degradation of cartilage could also be inhibited by the plant through suppression of MMP-3 and MMP-13 protein expressions. We also reported that the inhibitory effect of Payena dasyphylla on hyaluronidase activity and expression might be due to its anti-oxidant property

Challenges and opportunities in the design and construction of a GIS-based emission inventory infrastructure for the Niger Delta region of Nigeria

© 2017, Springer-Verlag Berlin Heidelberg. Environmental monitoring in middle- and low-income countries is hampered by many factors which include enactment and enforcement of legislations; deficiencies in environmental data reporting and documentation; inconsistent, incomplete and unverifiable data; a lack of access to data; and technical expertise. This paper describes the processes undertaken and the major challenges encountered in the construction of the first Niger Delta Emission Inventory (NDEI) for criteria air pollutants and CO2 released from the anthropogenic activities in the region. This study focused on using publicly available government and research data. The NDEI has been designed to provide a Geographic Information System-based component of an air quality and carbon management framework. The NDEI infrastructure was designed and constructed at 1-, 10- and 20-km grid resolutions for point, line and area sources using industry standard processes and emission factors derived from activities similar to those in the Niger Delta. Due to inadequate, incomplete, potentially inaccurate and unavailable data, the infrastructure was populated with data based on a series of best possible assumptions for key emission sources. This produces outputs with variable levels of certainty, which also highlights the critical challenges in the estimation of emissions from a developing country. However, the infrastructure is functional and has the ability to produce spatially resolved emission estimates

Neoplastic transformation of epithelial cells in whole mammary gland \u3ci\u3ein vitro\u3c/i\u3e

Biological characteristics of nodule-like alveolar lesions (NLAL) induced by 7,12-dimethylbenz[a]anthracene (DMBA) in organ culture of whole mammary gland (BALB/c female mice) were assessed after transplantation into gland-free mammary fat pads of syngeneic virgin mice. (i)Tissue- fragment explants from NLAL areas of the gland produced abnormal lobuloalveolar (LA) outgrowths in 3 of 10 fat pads. (ii) Transplantation of dissociated cells of NLAL-derived LA outgrowths into 36 fat pads showed 100% LA outgrowths and 3 (8%) of these 36 outgrowths produced mammary carcinomas. (iii) The explants of dissociated cells from whole mammary glands treated with DMBA in culture produced full or partial LA structures in 2 of 56 outgrowths. (iv) The explants of dissociated cells prepared from outgrowths derived from explants as in iii produced 9 LA outgrowths in 16 instances; mammary tumor incidence in these outgrowths was 3 of 16 (18%). (v) The explants of tissue fragments from LA outgrowths as in iv produced LA outgrowths in 20 of 20 fat pads; mammary carcinomas appeared in 16 of 20 (80%) of these outgrowths. No NLAL was detectable in control glands treated with dimethyl sulfoxide (solvent for DMBA); explants of the control glands consistently produced ductal outgrowths and no tumor. This accomplishment of chemical carcinogen-induced neoplastic transformation of epithelial cells in vitro provides a model for studying carcinogenesis in an entire isolated organ

Effects of addition of tilapia Oreochromis niloticus and substrates for periphyton developments on pond ecology and production in C/N-controlled freshwater prawn Macrobrachium rosenbergii farming systems

The present research investigated the effect of addition of tilapia and substrates for periphyton development on pond ecology, production and economic performances in C/N controlled freshwater prawn farming system. The absence and presence (0 and 0.5 individual m- 2) of tilapia were investigated in 40 m2 ponds stocked with 3 prawn juveniles (individual weight 5 g) m- 2 with or without added substrates for periphyton development. A locally formulated and prepared feed containing 30% crude protein (C/N ratio10) was applied daily, initially at 10% of the prawn stocked biomass and was gradually reduced to 3% of prawn biomass. Tapioca starch was used as carbohydrate source for increasing the C/N ratio from 10 (as in feed) to 20 and was applied to the water column separately from the feed. Addition of periphyton substrates significantly reduced the inorganic N-species (NH3-N, NO2-N and NO3-N) in the water column. It decreased the abundance of plankton in the overlying water and increased the abundance of benthic macroinvertebrates. The abundance of periphytic algae and periphyton biomass (dry matter, ash free dry matter and chlorophyll a) were significantly higher in tilapia free ponds compared to tilapia added ponds. Both substrates and tilapia had significant effects on feed conversion ratio (FCR) of freshwater prawn: substrates decreased FCR by 14% while tilapia addition increased it by 16%. The addition of substrates did not influence prawn and tilapia size at harvest but improved the survival of prawn from 54 to 77%. Substrates contributed 44% and 19% higher net yield of prawn and tilapia, respectively whereas tilapia addition decreased the net yield of prawn by 14%. The economic analysis showed that addition of tilapia and periphyton substrates jointly improved the benefit¿cost ratio. Addition of tilapia and periphyton substrates in C/N controlled system benefited the freshwater prawn culture practices through (1) reducing toxic inorganic nitrogenous compounds in water (2) enhancing the utilization of natural foods (3) improving survival, production and economic benefit