Induction of proliferation in isolated guinea pig gastric epithelium during restitution after superficial injury

Immediate repair of the gastrointestinal epithelium after superficial injury is called restitution. It is based on the migration of the surviving mucoid neck cells over the area of injury. The involvement of growth factors in the process has been recently documented. They are known to enhance the process (ie, EGF, FGF, TGF-beta) and to activate the basolateral Na+-H+-antiport (EGF). They may exert their effect by activating intracellular tyrosine kinases or by inducing chemotaxis. Yet, their precise mechanism of action in the process is unknown. The aim of the present study was to investigate the effect of modulation of the signal transduction pathway on the occurrence of proliferative mucoid neck and foveolar cells in guinea pig gastric epithelium. Therefore guinea pig gastric epithelium was mounted in Ussing chambers in vitro and perfused 4 hr after superficial injury with 1.25 M NaCl. The potential difference over the epithelium and tissue resistance were recorded simultaneously. The tissue was exposed either to cycloheximide, genistein, or to 4-phorbol myristate 13-acetate (PMA) during the 4-hr recovery, and the expression of proliferative cells was assessed by staining the tissue for proliferative cells (Ki-67). The mean proliferative index of tissues subjected to NaCl injury was significantly higher than that of uninjured control tissues after 4 hr of restitution. Inhibition of the signaling pathway with genistein decreased the proliferative index significantly, while its stimulation with phorbol myristate increased it. Both electrophysiologic and morphologic restitution were sensitive to genistein, but not to PMA or cycloheximide. Superficial epithelial injury results in a significantly increased occurrence of proliferative cells in isolated guinea pig gastric epithelium. This endogenous activation of the tissue is sensitive to inhibition by tyrosine kinases and to stimulation by protein kinases. Electrophysiologic and morphologic recovery are also affected by the modulation of the signaling pathway. This suggests that it is involved in the immediate repair process.     

Synthesis and characterization of conducting poly (1-aminonaphthalene), poly (2-aminonaphthalene) and poly (aniline-co-1-aminonaphthalene)

Poly (1&2)-aminonaphthalene and poly (aniline-co-1-aminonaphthalene) have been synthesized in high yields by chemical oxidative polymerization method. The polymers are soluble in polar solvents such as DMSO, NMP etc. In PNA-2 as head-to-tail coupling cannot occur, the electrical conductivity is lower than PNA-1. The copolymer exhibits distinct morphology, higher viscosity, characteristic exciton peak, appreciable thermal stability and electrical conductivity compared to PNA-1.     

Performance Study of 90° Bend Substrate Integrated Waveguide Band-Pass Filter with Multi-transmission Zeroes for MIC Applications

Wireless Personal Communications - In wireless sensor networks, the privacy of an event is critical to its safety. The location privacy of the sensor node that reports the event is imperative to...     

Characteristics Study of Physical,Mechanical and Tribological Behaviour of SiC/TiB2 Dispersed Aluminium Matrix Composite

Silicon - SiC and TiB2 particle reinforced Al7075 matrix composite has numerous applications such as aircraft structures, mould tool manufacturing, and structural application due to less weight to...     

mTrust: Call Behavioral Trust Predictive Analytics Using Unsupervised Learning in Mobile Cloud Computing

Filtering spam voice calls are a still major challenge in today’s technology contrary to SMS or email-based spamming. A numerical measure of the trust between users can help us filter calls based on relevance. Given the abundance of user-generated information available from the huge number of online devices, we can harness the power of this data to develop software adapting to user behavior. Existing research works for trust computation face various challenges when it comes to global applicability and understandability of trust values. Our investigation includes detailed surveillance of user call patterns based on the call data available from mobile devices and proposes a novel approach to filter calls that are of higher relevance to users based on their call-trust values. Our implementation realizes the diversity in call patterns of different people due to varying usage and uses classification and clustering algorithms to generate personalized, accurate numerical, and categorical trust values for every user. Categorical trust makes it easier to apply and understand trust ratings on a global scale. The implementation also incorporates a cloud facility to crowd-source trust values from multiple users, in a single database to generate the global trust of a user which can be used for spam filtering on a global scale. A software named “mTrust” is developed in this work for the future generation of a trustworthy mobile cloud network.

     

Synthesis and characterization of poly(2,5-dimethoxyaniline) and poly(aniline-Co-2,5-dimethoxyaniline): The processable conducting polymers

Poly(2,5-dimethoxyaniline) (PDMOA) and its copolymers with aniline (PADMOA), which exhibit remarkably improved solubility in common organic solvents, were obtained by chemical polymerization, and characterized by a host of physical techniques. The lowering of the quinoid absorption in the IR spectra and the upshifting of the N_1s envelope in the XPS spectra indicate residual doping in the XPS polymers and thermal characteristic of the polymers provide evidence for hydrogen bonding, which appear to enhance the thermal stability of the homopolymer. These polymers are highly planar and conjugated, with well-developed polaronic features, shown by the XRD, ESR and UV-spectral data. The conductivity, however, is not high and apparently may be due to localization of polaronic charges at the hydrogen-bonding sites and the increased proportion of the insulating methoxy component in the polymer matrix.