An Analysis of Causes of Urban Landslides in Residual Lateritic Soil

Landslides in natural slopes of residual soil are a common problem encountered in tropical regions. Guwahati city, located in Assam in the north-eastern part of India, is an urban watershed covered by a number of hills and hillocks that are capped with lateritic soil. Although the slopes originally consisted of hard and strong rocks, their stability have been impaired by weathering, heavy rainfall and seepage flows. Encroachments and cuttings on the hill slopes due to unplanned urbanisation and earthquake tremors have aggravated the problem. A study of landslides was undertaken focussing on degree of weathering of the rock units, their mineralogy and petrography, physical and mechanical properties as well as various structural features to identify the role of geology in initiating the slides. Soil samples obtained from the sites were tested. Data obtained from the field and laboratory were analysed to determine the causes of the landslides

Coexpression of PPE 34.9 Antigen of Mycobacterium avium subsp. Paratuberculosis with Murine Interferon Gamma in HeLa Cell Line and Study of Their Immunogenicity in Murine Model

Mycobacterium avium subsp. paratuberculosis (Map) is the causative agent of johne's disease whose immunopathology mainly depends on cell mediated immuneresponse. Genome sequencing revealed various PPE (Proline-Proline-Glutamic acid) protein family of Map which are immunologically importance candidate genes In present study we have developed a bicistrionic construct pIR PPE/IFN containing a 34.9 kDa PPE protein (PPE 34.9) of Map along with a cytokine gene encoding murine gamma Interferon gene (IFNγ) and a monocistrionic construct pIR PPE using a mammalian vector system pIRES 6.1. The construct were transfected in HeLa cell line and expression were studied by Western blot as well as Immunefluroscent assay using recombinant sera. Further we have compared the immunereactivity of these two constructs in murine model by means of DTH study, LTT, NO assay and ELISA. DTH response was higher in pIR PPE/IFN than pIR PPE group of mice, similar finding also observed in case of LTT and NO production assay . ELISA titer of the pIR PPE/IFN was less than that with PPE only. These preliminary finding can revealed a CMI response of this PPE protein of Map and IFNγ having synergistic effect on this PPE protein to elicit a T cell based immunity in mice

Expression of a Gene Encoding 34.9 kDa PPE Antigen of Mycobacterium avium subsp. paratuberculosis in E. coli

Mycobacterium avium subsp. paratuberculosis (Map) contains PPE family antigens which are Proline and glutamic acid rich and may play important role as T cell antigens. Hence the identification and generation of antigens are necessary for immunological characterization. In the present study, the epitopic region of a unique PPE gene encoding 34.9 kDa protein from Map was amplified by polymerase chain reaction. The gene was cloned into Escherichia coli vector pQE30 UA. The recombinant plasmid designated as pQPPE was transformed into E. coli M15 and induced with IPTG revealed the high level expression of 37.1 kDa His-fusion protein (34.9 kDa PPE and 2.2 kDa His-tag), which was confirmed by immunoblotting. Recombinant PPE protein was then purified by Ni-NTA agarose chromatography. The polyclonal antiserum raised against purified recombinant PPE protein reacted with expressed 37.1 kDa His-fusion protein as well as with Map sonicate. The protein elicited significant delayed type hypersensitivity (DTH) skin reaction in mice sensitized with Map. The results indicated that the recombinant PPE protein of Map was associated with cellular immune response

Stability Analysis of Flood Protection Embankments and Riverbank Protection Works

Frequent and widespread flooding is a major problem in Assam, which is a north-eastern state of India. The problem is caused mainly by the Brahmaputra river whose erratic riverbank erosion has been leading to general widening of channels and large-scale instability of banks. In the last century, the river has widened by more than 50% in several stretches causing serious threat to nearby urban centres apart from eroding several thousand hectares of fertile agricultural land including tea gardens. As of now, the width between outer banks ranges from as low as 1.2 km at some sections to as high as 18 km at some reaches. Both the flooding and erosion in the river valley can be tackled only through an adaptive response that includes the use of structural protection systems. A practicability study was conducted for raising the height of existing flood embankments in a particular reach of the river. Stability analysis was carried out to determine safety factors under static conditions and earthquake loading. Riverbank protection works are also discussed

Author Correction:Charge disproportionate molecular redox for discrete memristive and memcapacitive switching (Nature Nanotechnology, (2020), 15, 5, (380-389), 10.1038/s41565-020-0653-1)

Correction to: Nature Nanotechnology. Published online 23 March 2020. In the version of this article initially published, there were presentation errors in the range of y-axis values displayed in Extended Data Figure 4a,b, and Extended Data Figure 5b. The errors have been corrected in the HTML and PDF versions of the article.</p

Thermal analysis of Si-IGBT based power electronic modules in 50kW traction inverter application

Estimation of accurate IGBT junction temperature is crucial for reliability assessment. The well-known RC lumped approach can help predict junction temperature. However, this method suffers from inaccuracy while characterizing the thermal behaviour of several IGBT modules mounted to the liquid-cooled heatsink. Specifically, the thermal challenge originates from the thermal cross-coupling and module-to-module heat spreading and the converter cooling condition. This article demonstrates a methodology to study the impact of heat spreading, thermal interface material, and massive size liquid cold-plate on the overall thermal behaviour. A case study of 50 kW traction inverter is chosen to demonstrate the benefit of early assessment of electro-thermal simulation before making costly prototype design. Power loss is initially estimated using an analytical loss model and later the estimated power loss is used in FEA (Finite Element Analysis) thermal model. This paper also compares the performance of single-phase and two-phase liquid cooling and various thermal interface materials (TIM) to determine which type of cooling system and TIM is most suitable for real applications. Simulation results suggest that combination of two-phase liquid cooling and TIM can improve the thermal performance and reduce junction temperature by 4.5%, 4.2%, 4.6% for the traction power load 30 kW, 40 kW, and 50 kW, respectively. The proposed methodology can be used as useful reference guidance for thermal design and modelling of IGBT based power converter applications