Thyroid cancer risk in Belarus among children and adolescents exposed to radioiodine after the Chornobyl accident

BACKGROUND: Previous studies showed an increased risk of thyroid cancer among children and adolescents exposed to radioactive iodines released after the Chornobyl (Chernobyl) accident, but the effects of screening, iodine deficiency, age at exposure and other factors on the dose-response are poorly understood. METHODS: We screened 11 970 individuals in Belarus aged 18 years or younger at the time of the accident who had estimated (131)I thyroid doses based on individual thyroid activity measurements and dosimetric data from questionnaires. The excess odds ratio per gray (EOR/Gy) was modelled using linear and linear-exponential functions. RESULTS: For thyroid doses \u3c5 \u3eGy, the dose-response was linear (n=85; EOR/Gy=2.15, 95% confidence interval: 0.81-5.47), but at higher doses the excess risk fell. The EOR/Gy was significantly increased among those with prior or screening-detected diffuse goiter, and larger for men than women, and for persons exposed before age 5 than those exposed between 5 and 18 years, although not statistically significant. A somewhat higher EOR/Gy was estimated for validated pre-screening cases. CONCLUSION: 10-15 years after the Chornobyl accident, thyroid cancer risk was significantly increased among individuals exposed to fallout as children or adolescents, but the risk appeared to be lower than in other Chornobyl studies and studies of childhood external irradiation

The Flux-Line Lattice in Superconductors

Magnetic flux can penetrate a type-II superconductor in form of Abrikosov vortices. These tend to arrange in a triangular flux-line lattice (FLL) which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-$T_c$ supercon- ductors (HTSC's) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft mainly because of the large magnetic penetration depth: The shear modulus of the FLL is thus small and the tilt modulus is dispersive and becomes very small for short distortion wavelength. This softness of the FLL is enhanced further by the pronounced anisotropy and layered structure of HTSC's, which strongly increases the penetration depth for currents along the c-axis of these uniaxial crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause thermally activated depinning of the flux lines or of the 2D pancake vortices in the layers. Various phase transitions are predicted for the FLL in layered HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do not exist as postscript file

Prevention of neutropenia during chemotherapy by prolonged myelostimulatory preparations

Neutropenia and associated infection, resulting in hospitalization and use of antibiotics, has a negative effect on chemotherapy. The need to reduce the dose of cytotoxic drugs during neutropenia leads to lower survival rates in patients with hematological malignancies and solid tumors. Since 1990s myelocytokines – proteins that accelerate neutrophil recovery after cytostatic chemotherapy and reduce the risk of infection – is widely used in the clinical practice. The use of these drugs can support the planned dose intensity of chemotherapy and improves the treatment efficacy. The disadvantages of these drugs include the need for their daily parenteral administration for 7–10 days. The development of long-acting forms (pegfilgrastim and lipegfilgrastim) has solved this problem. Self-regulating clearance of prolonged forms allowed to use them only once on a chemotherapy course. Results of pegfilgrastim administration in 25 patients with hematological malignancies (8 patients) and solid tumors (17 patients) included in our analysis. Prolonged preparation showed high efficacy in secondary prophylaxis of neutropenia and infection decreasing the risk by 82 %. The single administration of pegfilgrastim allowed safe dose intensity chemotherapy with shorter intervals between courses (AC-14) in 8 patients with breast cancer. Tolerability was good; cases of hyperleukocytosis have notbeen reported. Recently in Europe and the Russian Federation a new drug from prolonged myelocytokine group – lipegfilgrastim – has been registered. The results of two controlled trials in patients with breast cancer (n = 410) receiving doxorubicin/docetaxel showed high efficacy of the drug as the pegfilgrastim with comparable tolerability

Prevention of neutropenia during chemotherapy by prolonged myelostimulatory preparations

Neutropenia and associated infection, resulting in hospitalization and use of antibiotics, has a negative effect on chemotherapy. The need to reduce the dose of cytotoxic drugs during neutropenia leads to lower survival rates in patients with hematological malignancies and solid tumors. Since 1990s myelocytokines – proteins that accelerate neutrophil recovery after cytostatic chemotherapy and reduce the risk of infection – is widely used in the clinical practice. The use of these drugs can support the planned dose intensity of chemotherapy and improves the treatment efficacy. The disadvantages of these drugs include the need for their daily parenteral administration for 7–10 days. The development of long-acting forms (pegfilgrastim and lipegfilgrastim) has solved this problem. Self-regulating clearance of prolonged forms allowed to use them only once on a chemotherapy course. Results of pegfilgrastim administration in 25 patients with hematological malignancies (8 patients) and solid tumors (17 patients) included in our analysis. Prolonged preparation showed high efficacy in secondary prophylaxis of neutropenia and infection decreasing the risk by 82 %. The single administration of pegfilgrastim allowed safe dose intensity chemotherapy with shorter intervals between courses (AC-14) in 8 patients with breast cancer. Tolerability was good; cases of hyperleukocytosis have notbeen reported. Recently in Europe and the Russian Federation a new drug from prolonged myelocytokine group – lipegfilgrastim – has been registered. The results of two controlled trials in patients with breast cancer (n = 410) receiving doxorubicin/docetaxel showed high efficacy of the drug as the pegfilgrastim with comparable tolerability.</p

Optical transmission of nematic liquid crystal 5CB doped by single-walled and multi-walled carbon nanotubes

Comparative studies of optical transmission of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs), dispersed in nematic liquid crystal matrix 5CB, were carried out. The data evidence violations of Beer-Lambert-Bouguer (BLB) law both in cell thickness and concentration dependencies. The most striking is the fact that optical transmission dependencies for SWCNTs and MWCNTs were quite different in the nematic phase, but they were practically indistinguishable in the isotropic phase. Monte Carlo simulations of the impact of aggregation on direct transmission and violation of BLB law were also done. The results were discussed accounting for the tortuous shape of CNTs, their physical properties and aggregation, as well as strong impact of perturbations of the nematic 5CB structure inside coils and in the vicinity of CNT aggregates