Investigation of gain enhancement of electrically small antennas using double-negative, single-negative, and double-positive materials

In this paper, it is shown that a double-negative or a mu-negative shell can be used to achieve a very high gain for an electrically small loop. It is also seen that together with the high gain, the metamaterial shell can be used to achieve a very uniform gain characteristic with respect to the shell dimensions. This is accomplished by a proper choice of the media parameters of the metamaterial shell and the region surrounding the antenna. This significantly eases the fabrication constraints and the close tolerances on the shell which was a major drawback towards the practical realization of the shell. Also, significant power gain can be obtained when the radiated power from the metamaterial shell is compared to the power radiated by a loop of the same radius as the outer radius of the shell. In addition, it is also found that a double-positive shell of the same dimensions as the metamaterial shell can be used to significantly increase the gain of the infinitesimal antenna. The power gain characteristics show distinct resonant peaks in this case. Excellent matching characteristics are observed corresponding to the radiated power gain.

A single nucleotide polymorphism (A --> G) in intron 3 of IFNgamma gene is associated with asthma

Interferon-gamma (IFNgamma) is located on chromosome 12, and a number of studies have detected very strong linkage signals around this gene and asthma. The aim of this study was to analyze the association of a (CA)n repeat in intron 1 and six single nucleotide polymorphisms (((rs2069705, T/C) (promoter)), ((rs1861494, A/G), (rs1861493, T/C), (rs2069718, C/T) (intron 3)), ((rs2069727, A/G) and (rs2069728, G/A) (3' untranslated region))) spanning the whole gene with asthma. We report here the association of rs1861494 A/G with atopic asthma in a case-control cohort (n=189 and n=270 cases and controls, respectively) (P=0.0006), which was replicated (P=0.006) in a family study (n=137) as well. Allele G was found to be negatively associated (odds ratio=0.50, 95% confidence interval, P=0.0006). A five-locus haplotype also showed significant association with asthma in the case-control (P=0.002) and the family studies (P=0.0004). In our three-locus sliding window haplotypic analysis, we found the (CA)n repeat, rs1861494 A/G and rs2069718 C/T to be of high priority (P=0.0003). Using electrophoretic mobility shift assay, we provide evidence that the alleles of rs1861494 A/G have differential affinity to bind to putative nuclear factor(s). In conclusion, we report for the first time association of rs1861494 A/G polymorphism with asthma, which may regulate the IFNgamma levels and, hence, modulate asthma pathogenesis.

Association of TNF polymorphisms with sarcoidosis, its prognosis and tumour necrosis factor (TNF)-alpha levels in Asian Indians

Tumour necrosis factor (TNF)-alpha, an important proinflammatory cytokine, has been implicated in the pathogenesis of sarcoidosis, a multi-systemic granulomatous disorder of unknown aetiology. Here, we report for the first time the association of TNF haplotypes and genotypes with sarcoidosis and its prognosis in the Indian population. Five potentially functional promoter polymorphisms in the TNFA gene and a LTA_NcoI polymorphism (+252 position) of the LTA gene were genotyped in a clinically well-defined cohort of North-Indian patients with sarcoidosis (n = 96) and their regional controls (n = 155). Serum TNF-alpha (sTNF-alpha) and serum angiotensin converting enzyme (SACE) levels were measured and correlated with genotypes and haplotypes. The TNFA_-1031 and TNFA_-863 polymorphisms were identified as markers for disease onset (FET P = 0.006 and 0.042 for TNFA_-1031 and TNFA_-863, respectively). Additionally, the allele A of LTA_NcoI polymorphism was shown to be prevalent in the 'no treatment' group (FET P = 0.005), while the G allele was associated with frequent relapses on drug withdrawal (P = 0.057). Furthermore, the TNFA-308G>A and the TNFA-238G>A polymorphisms were found to influence sTNF-alpha (P = 0.054 and 0.0005, respectively) and SACE levels (P = 0.0017 and 0.056, respectively). The haplotype frequencies were significantly different in the patients and the controls (P = 0.0067). The haplotype GTCCGG was identified as the major risk/susceptibility haplotype (P = 0.003) and was associated with increased SACE levels in the patient population. In conclusion, our study suggests an association of TNF polymorphisms with sarcoidosis.

Modeling Study of Rusticyanin-Cytochrome C4Complex: An Insight to Possible H-Bond Mediated Recognition and Electron—Transfer Process

Rusticyanin (RCy) mediated transfer of electron to Cytochrome C(4) (Cytc(4)) from the extracellular Fe(+2) ion is primarily involved in the Thiobacillus ferrooxidans induced bio-leaching of pyrite ore and also in the metabolism of this acidophilic bacteria. The modeling studies have revealed the two possible mode of RCy-Cytc(4) complexation involving nearly the same stabilization energy approximately -15 x 10(3) kJ/mol, one through N-terminal Asp 15 and another -C terminal Glu 121 of Cytc(4) with the Cu-bonded His 143 of RCy. The Asp 15:His 143 associated complex (DH) of Cytc(4)-RCy was stabilized by the intermolecular H-bonds of the carboxyl oxygen atoms O(delta1) and O(delta2) of Asp 15 with the Nepsilon-atom of His 143 and O(b) atoms of Ala 8 and Asp 5 (of Cytc(4)) with the Thr 146 and Phe 51 (of RCy). But the other Glu 121:His 143 associated complex (EH) of Cytc(4)-RCy was stabilized by the H-bonding interaction of the oxygen atoms O(epsilon1) and O(epsilon2) of Glu 121 with the Nepsilon and Ogamma atoms of His 143 and Thr 146 of RCy. The six water molecules were present in the binding region of the two proteins in the energy minimized autosolvated DH and EH-complexes. The MD studies also revealed the presence of six interacting water molecules at the binding region between the two proteins in both the complexes. Several residues Gly 82 and 84, His 143 (RCy) were participated through the water mediated (W 389, W 430, W 413, W 431, W 373, and W 478) interaction with the Asp 15, Ile 82, and 62, Tyr 63 (Cytc(4)) in DH complex, whereas in EH complex the Phe 51, Asn 80, Tyr 146 (RCy) residues were observed to interact with Asn 108, Met 120, Glu 121 (of Cytc(4)) through the water molecules W 507, W 445, W 401, W 446, and W 440. The direct water mediated (W 478) interaction of His 143 (RCy) to Asp 15 (of Cytc(4)) was observed only in the DH complex but not in EH. These direct and water mediated H-bonding between the two respective proteins and the binding free energy with higher interacting buried surface area of the DH complex compare to other EH complex have indicated an alternative possibility of the electron transfer route through the interaction of His 143 of RCy and the N-terminal Asp 15 of Cytc(4).

Total serum immunoglobulin E levels in a case-control study in asthmatic/allergic patients, their family members, and healthy subjects from India

BACKGROUND

Total immunoglobulin E (IgE) is an important indicator of allergic disorders. However, its role in allergic patients in India has not been evaluated in relation to atopic status for a reference range as compared with healthy subjects.

OBJECTIVE

The aim of the study was to establish serum IgE levels in a diseased group, study its relationship with atopy, and to compare the same with healthy volunteers in Indian subjects.

METHODS

Four hundred and eighty asthmatics/allergic patients, 100 first-degree relatives of asthmatics, and 120 unrelated normal healthy volunteers from Delhi region were recruited for the study. Atopy was established by family history and skin test to common indigenous allergens and, total and specific IgE measurements. Statistical analysis was performed with the help of SPSS software program.

RESULTS

The mean IgE levels were the highest in asthmatic patients and the lowest in the control healthy group. IgE was significantly high in the male than the female healthy volunteers (P<0.05), but not in the diseased group. Prosopis juliflora among pollen allergens and Alternaria alternata among fungal allergens were important sensitizers in allergic patients with 34.7% and 17.7% skin positivity, respectively. Atopic status and asthma were found to be the best predictor of IgE, which was highly significant (r(2)=0.239, P<0.00001). However, at 95% confidence interval as many as 50% of asthmatic patients had their IgE values in the normal range.

CONCLUSION

The IgE levels in Indian allergic patients is significantly related to atopy, but due to wide overlap of IgE levels in patients and healthy subjects, its diagnostic significance in Indian population seems to be limited.

Conserved Water Molecular Dynamics of the Different X-ray Structures of Rusticyanin: An Unique Aquation Potentiality of the Ligand Bonded Cu++Center

The invariant water molecular interaction involving in the Rusticyanin of Thiobacillus ferrooxidans is thought to be important for its molecular complexation with other proteins at differential acidophilic situation. The comparative analysis of the different x-ray, energy minimized, and auto solvated structures of Rusticyanin revealed the presence of five specific invariant bound water molecules (among the approximately 150 water molecules per monomer) in the crystals. The five W 205, W 206, W 112, W 214, and W 221 water molecules (in Rusticyanin PDB code: 1RCY) were seem to be invariant in all the seven structures (PDB codes: 1RCY, 1A3Z, 1A8Z, 1E3O, 1GY1, 1GY2, 2CAL). Among the five conserved water molecules the W 221 (of 1 RCY or the equivalent water molecules in the other oxidized form of Rusticyanin structures) had endowed an interesting coordination potentiality to Cu(+2) ion during the energy minimization. The W 221 was observed to approach toward the tetrahedrally bonded Cu(+2) ion through the opposite (or trans) route of metal-bonded Met 148. This direct water molecular coordination affected the tetrahedral geometry of Cu(+2) to trigonal bipyramidal. Presumably this structural dynamics at the Cu(+2) center could involve in the electron transport process during protein-protein complexation.