Pawandeep Kaur

Complex permittivity, permeability and microwave absorbing properties of Co–Ti substituted strontium hexaferrite

Abstract M-type strontium ferrite with compositions SrFe(12-2x)CoxTixO19 (x = 0.0, 0.3, 0.5, 0.7, 1.0), were prepared by two route ceramic method. The effects of Co–Ti substitution on their microstructure, electromagnetic properties, and microwave absorptive behavior were analyzed. The complex permittivity (∊′-j∊″) and complex permeability (μ′-jμ″) have been measured from 8.2 to 12.4 GHz using a network analyzer. Scanning electron microscope was used to analyze the grain size distribution and porosity of the ferrite. X-ray diffraction confirmed the M-type structure of the doped strontium ferrite. Vibrating sample magnetometer was used to study hysteresis loop of the ferrite. This study suggests that the control of grain size, decrease in coercivity and enhanced values of dielectric constant and loss are effective means to improve microwave absorption. The dielectric constant and loss were enhanced in comparison to the permeability constant and loss over the entire frequency range.

Lymphocytic Chromosomal Instability in Sporadic Gastrointestinal Tract (GIT) Cancer Patients and their First-Degree Relatives

Abstract The present study was an attempt to assess utility of chromosomal instability in peripheral blood lymphocytes of first-degree relatives (FDR) of sporadic gastrointestinal tract (GIT) cancer patients for genetic surveillance. Standard lymphocyte culture technique was used for the purpose. Cultured peripheral blood lymphocyte metaphases were scored for aberrations in 10 sporadic cases of GIT cancer patients (6-esophageal, 1-gastric, 2-rectum and 1-cecum), 10 first-degree relatives and 10 healthy unrelated controls. There were significantly increased number of aberrations in cancer patients as compared to FDRs and controls. A perceptible increase in the level of metaphases with structural aberrations, including gaps, breaks, rings, centromeric separation and terminal deletions, was observed in first-degree relatives of cancer patients as compared to healthy unrelated controls taken from the same geographical area. There was high frequency of aberrations, mainly structural aberrations, involving specific chromosomes in firstdegree relatives and in cancer patients. Majority of aberrations were at chromosomal loci harboring genes involved directly or indirectly in tumorigenesis, thus indicating the probability of a constitutional chromosomal instability in first-degree relatives of even sporadic GIT cancer patients.

Fabrication and microwave absorption properties of hexaferrite composites in Ku-band

In this research, M-type hexaferrites doped with Co,Ti, Sr(CoTi)xFe(12-2x)O19 (x=0.0, 0.2, 0.4, 0.8, 1.0) have been synthesized using normal ceramic technique. Properties like complex permittivity, complex permeability and reflection loss of composites of these hexaferrites with epoxy resin have been measured in Ku-band i.e. 12.4-18 GHz.