First report on phytoplankton communities of Barishal City, Bangladesh

Phytoplanktons, also called microalgae, are microscopic photosynthetic living organisms that generally found in aquatic environments. Although they are considered as the most important primary producers and bioindicators of aquatic ecosystems, there was no previous report found for Barishal City about these tiny organisms. Consequently, the present study selected 10 freshwater reservoirs from the city to investigate phytoplankton communities and listed 110 taxa under 4 phyla, 7 classes, 18 orders, 24 families and 49 genera. The distribution of Chlorophytes was abundant relatively in terms of species number (45 taxa) followed by Euglenophytes, Chlorophytes and Cyanophytes in this area. Only Euglenaceae possessed one-third of the total species of this report. Among all stations, the highest number of taxa was recorded from station 2 and according to nine biodiversity indices, the station 2 and 9 showed comparatively good results. All of the recorded taxa were previously mentioned by different authors from Bangladesh

Effect of plant growth regulators on growth and yield of chili (Capsicum annuum L.)

Chili (Capsicum annuum L.) is an important food additive with high medicinal value. To investigate the effect of plant growth regulators on chili, seedlings of chili were collected from the local market and grown in the experimental field of the University of Barishal, Bangladesh. Foliar spray of different degrees of plant growth regulators, Gibberellin (50 mg/l, 100 mg/l, 250mg/l, 350 mg/l GA3) and Cytokinin (50 mg/l, 100 mg/l, 250mg/l, 350mg/l Kn) were applied from 15 days of germination. Data on different growth and yield parameters were collected and analyzed statistically. The result reveals that there is a significant difference in growth and yield related traits in chili due to the application of plant growth regulators. An optimum level of PGRs application shows better performance compare with control. Plant height particularly influenced by GA3 whereas other attributes like the number of leaves, branches, flowers and fruits are greatly influenced by the application of kinetin

Impact of Chemical Reaction on MHD Mixed Convection Heat and Mass Transfer Flow with Thermophoresis

A mathematical model is analyzed in order to study the effects of chemical reaction and thermophoresis on MHD mixed convection boundary layer flow of an incompressible, electrically conducting fluid past a heated vertical permeable flat plate embedded in a uniform porous medium, by taking into account the radiative heat flux and variable suction. The governing partial differential equations are transformed into a set of coupled ordinary differential equations which are solved analytically using the regular perturbation technique. Numerical results for dimensionless velocity, temperature, concentration as well as the skin friction coefficient, Nusselt number and Sherwood number are presented through graphs and a table for pertinent parameters to show interesting aspects of the solution. doi:10.14456/WJST.2014.3

Anti-Microbial Study of Shwasakuthar Rasa: In Vitro Study

Shwasa kuthar Rasa is well known drug used in Respiratory disorders in Indian System of Medicine. It is herbomineral formulation made up of Parada, Gandhaka, Vatsanabha, Tankana, Manashila, Maricha, Pippali, Sunthi by triturating in Tambula patra Swarasa and indicated in Shwasa, Kasa, Mandagni, disorders prominent in Vata-Shleshma doshas. These action of Shwas kuthar rasa may be due to its antimicrobial activity, so that in vitro antimicrobial activity was assessed by Agar Disc Diffusion method with reference to staphylococcus aureus. In-vitro tests are necessary to help determine initial dose-response data as well as to evaluate potential susceptibility and/or resistance of specific pathogens. In-vitro systems include the ability to control the number of bacteria, extent of antimicrobial-bacteria contact time, as well as the influence of various environmental factors, such as oxygen tension, pH, and temperature. Agar dilution methods are to determine the lowest concentration of the assayed Shwas kuthar rasa as antimicrobial agent (minimal inhibitory concentration, MIC) that, under defined test conditions, inhibits the visible growth of the bacterium being investigated. MIC values are used to determine susceptibilities of bacteria to drugs and also to evaluate the activity of new antimicrobial agents

Enhanced shot noise at bilayer graphene-superconductor junction

Transport properties of graphene-superconductor junction have been studied extensively to understand the interplay of the relativistic Dirac quasiparticles and superconductivity. Though shot noise measurements in graphene have been performed to realize many theoretical predictions, both at zero magnetic field as well as quantum Hall (QH) regime, its junction with superconductor remain unexplored. Here, we have carried out the shot noise measurements in an edge contacted bilayer graphene-niobium superconductor junction at zero magnetic field as well as QH regime. At the Dirac point we have observed a Fano factor similar to 1/3 above the superconducting gap (Delta) and a transition to an enhanced Fano factor similar to 0.5 below the superconducting gap. By changing the carrier density we have found a continuous reduction of Fano factor for both types of carriers; however, the enhancement of Fano factor within the superconducting gap by a factor of similar to 1.5 is always preserved. The enhancement of shot noise is also observed in the QH regime, where the current is carried by the edge state, below the critical magnetic field and within the superconducting gap. These observations clearly demonstrate the enhanced charge transport at the graphene-superconductor interface

Bio-tribological response of duplex surface engineered SS316L for hip-implant application

Here we report on intelligently planned duplex surface engineering concept that utilizes a combination of plasma nitriding and multi-layering for optimizing cyclic fatigue resistance. This new concept of duplex surface engineering treatment is utilized to achieve improvement in cyclic fatigue as well as bio-tribological response of SS316L (SS) based hip-implants. The samples are SS316L (SS), Ti/TiN multi-layer-coated SS i.e., SSML and Ti/TiN multi-layer-coated plasma nitrided SS i.e., SSPNML. The samples are characterized by XRD, FESEM, TEM, nanoindentation, micro-scratch and sliding wear. In addition, cyclic fatigue behaviour up to 1 million cycles of SS and SSPNML femur heads against UHMWPE acetabular cups are studied using a hip simulator. The results prove that under comparable conditions, the nanohardness, micro-scratch resistance and sliding wear resistance of the SSPNML samples in SBF are much better than those of the corresponding SSML and SS samples. Further, as compared to the SS femoral head, the SSPNML femoral head is found to be much more resistant to cyclic fatigue. These results establish beyond doubt the superiority of the duplex surface engineering treatment utilized in the present work to achieve superb cyclic fatigue resistance in SS based femoral heads for bio-prosthetic hip implants

Nanotribological response of a plasma nitrided bio-steel

AISI 316L is a well known biocompatible, austenitic stainless steel (SS). It is thus a bio-steel. Considering its importance as a bio-prosthesis material here we report the plasma nitriding of AISI 316L (SS) followed by its microstructural and nanotribological characterization. Plasma nitriding of the SS samples was carried out in a plasma reactor with a hot wall vacuum chamber. For ease of comparison these plasma nitrided samples were termed as SSPN. The experimental results confirmed the formations of an embedded nitrided metal layer zone (ENMLZ) and an interface zone (IZ) between the ENMLZ and the unnitrided bulk metallic layer zone (BMLZ) in the SSPN sample. These ENMLZ and IZ in the SSPN sample were richer in iron nitride (FeN) chromium nitride (CrN) along with the austenite phase. The results from nanoindentation, microscratch, nanoscratch and sliding wear studies confirmed that the static contact deformation resistance, the microwear, nanowear and sliding wear resistance of the SSPN samples were much better than those. of the SS samples. These results were explained in terms of structure property correlations. (C) 2016 Elsevier Ltd. All rights reserved

Nano- and micro-tribological behaviours of plasma nitrided Ti6Al4V alloys

Plasma nitriding of the Ti-6Al-4V alloy (TA) sample was carried out in a plasma reactor with a hot wall vacuum chamber. For ease of comparison these plasma nitrided samples were termed as TAPN. The TA and TAPN samples were characterized by XRD, Optical microscopy, FESEM, TEM, EDX, AFM, nanoindentation, micro scratch, nanotribology, sliding wear resistance evaluation and in vitro cytotoxicity evaluation techniques. The experimental results confirmed that the nanohardness, Young's modulus, micro scratch wear resistance, nano wear resistance, sliding wear resistance of the TAPN samples were much better than those of the TA samples. Further, when the data are normalized with respect to those of the TA alloy, the TAPN sample showed cell viability about 11% higher than that of the TA alloy used in the present work. This happened due to the formation of a surface hardened embedded nitrided metallic alloy layer zone (ENMALZ) having a finer microstructure characterized by presence of hard ceramic Ti2N, TiN etc. phases in the TAPN samples, which could find enhanced application as a bioimplant material