London penetration depth in the tight binding approximation: Orthorhombic distortion and oxygen isotope effects in cuprates

We present a simple derivation of an expression for the superfluid density $n_s \propto 1/\lambda^2$ in superconductors with the tight binding energy dispersion. The derived expression is discussed in detail because of its distinction from the known expressions for ordinary superconductors with parabolic energy dispersion. We apply this expression for the experimental data analysis of the isotope effect in London penetration depth parameter $\lambda$ in the BiSrCuO and YBaCuO family compounds near optimal doping, taking into account the orthorhombic distortion of crystal structure, and estimate the isotopic change of hopping parameters from the experimental data. We point out that $1/\lambda^2$ temperature behaviour is very sensitive to the ratio $2\Delta_m(T=0)/ k_B T_c$ and estimate this quantity for a number of compounds.Comment: 10 pages, 4 figure

Specific features of immunity in neonatal infants with localized and generalized bacterial infections

Cellular immunity indicators were investigated in infants with localized (и=10) and generalized (и=15) bacterial infections (sepsis). The blood levels of different groups of white blood cells (neutrophils, lymphocytes, monocytes) and lymphocyte subpopulations (CD3, CD4, CD8, CD16/56, and CD19) were estimated. The development of sepsis was accompanied by leukocytosis and leukopenia in 47 and 20% of the cases, respectively. In localized infections, there was leukocytosis in 30% of the infants and leukopenia in 10%. Absolute lymphopenia was present in 40% of the cases of sepsis and in 20% of those of localized infections. The acute period of neonatal sepsis was accompanied by a substantial reduction in the level of CD3+, CD4+, CD8+, and CD16/56+ lymphocyte subpopulations. The highest changes were recorded in the CD4+ and CD16/56+: their counts were decreased by an average of 3,9 and 3,6 times, respectively, compared to the control values; CD8+ lymphocytes dropped by 2,7 times. Localized infections were characterized by a predominant fall in the number of CD4+ and CD16/56+ subpopulations. Moreover, the level of CD4+ lymphocytes was significantly lower than that in the sepsis group. Thus, the acute period of both localized and generalized bacterial infections took place in the presence of cellular immunity suppression. The most marked changes were recorded in sepsis. The f

Neonatal sepsis caused by Klebsiella

Klebsiella is one of the most common causes of neonatal sepsis. Cases caused by extended-spectrum β-lactamase-producing Klebsiella strains are of the most relevance. The infections caused by these bacterial strains are resistant to the majority of cephalosporins commonly used in practice and lead to significant mortality. The development of their clinical forms, including severe ones, is determined by a number of virulence factors that include capsular antigen, lipopolysaccharide, pili, and siderophores. Despite the fact that the probability of sepsis is highest in premature infants, full-term ones are equally at risk in the situations associated by the infection due to extended-spectrum β-lactamase-producing Klebsiella. Our investigation of the specific features of the course of neonatal sepsis caused by Klebsiella established that hemorrhagic syndrome evolving in the presence of thrombocytopenia is the most common condition developing in Klebsiella-induced sepsis that determines the severity of a patient’s condition and affects the outcome of the disease

Mie resonant diamond nanoantennas for spontaneous light emission

The size of the hosting particle affects the spontaneous light emission of embedded emitters. Here we study submicron-sized diamond particles containing silicon-vacancy color centers. We measure size-dependent scattering spectra, fluorescence emission rate, and Raman scattering intensity. Obtained results are found to agree with our calculations and demonstrate the potential of Mie resonances in nanoantennas design