Analiza zmian strukturalnych monokryształów niobianu strontowo - barowego w obszarze przejścia fazowego

The aim of this thesis was to characterize a structural phase transition. The high quality single crystals of SrxBa1-xNb2O6 (0.35 < x < 0.72) solid solutions obtained by the Czochralski method were investigated. Using X-ray Bond's method lattice parameters of this crystals are determined with high accuracy in the order of Δd/d ≈ 10-5. The accurate values of lattice parameters were educed from absolute shift of the reflex position which was due to systematic uncertainty. Registered temperature changes a and c parameters have permitted accurate determination of the phase transition temperature TC. The occurrence of anisotropy of thermal expansion below TC was affirmed. The c parameters exhibit a negative coefficient of thermal expansion along [001] direction while the a parameters exhibit a positive one along [100] direction for all studied compositions. A conventional analysis of lattice parameter data in terms of spontaneous strain and strain/order parameter coupling shows that a normal structural phase transition does occur. The ferroelectric systems (SBN35, SBN40 and SBN42) display a nearly tricritical behavior, β ≈ 0.20. While the relaxor ones (SBN59 and SBN72) complies with the two-dimensional Ising-model-like criticality, β ≈ 0.17. Additionally, analysis of recorded diffraction patterns obtained using the four circle diffractometer, allowed to observe several signs of crystal structure modulation

Primary crystal orientation of the thin-walled area of single-crystalline turbine blade airfoils

The thin-walled airfoil areas of as-cast single-crystalline turbine blades made of CMSX-4 superalloy were studied. The blades were produced by the industrial Bridgman technique at withdrawal rates of 2, 3 and 4 mm/min. The angle between the [001] crystallographic direction and blade axis, related to the primary orientation, was defined by the Ω-scan X-ray diffraction method at points on the camber line located near the tip of an airfoil and at points of a line located in parallel and near the trailing edge. Additionally, primary crystal orientation was determined by Laue diffraction at the selected points of an airfoil. The influence of mould wall inclination on the primary crystal orientation of the thin-walled areas is discussed. The effect of change in the [001] crystallographic direction, named as "force directing", was considered with regard to the arrangement of primary dendrite arms in relation to the trailing edge and the camber line. It was stated that when the distance between the mould walls is less than the critical value of about 1.5 mm the "force directing" increases as the distance between the walls of the mould decreases. The effect may be controlled by selecting an appropriate secondary orientation using a seed crystal in the blade production process. The model of dendrite interaction with the mould walls, including bending and "deflection", was proposed

Use of a levonorgestrel-releasing intrauterine device for menorrhagia treatment during adjuvant therapy of adrenocortical carcinoma with mitotane

Adrenocortical carcinoma is a rare tumour with high malignancy and poor prognosis. This tumour is rarely diagnosed in the reproductive age. Complete surgical resection is the only curative treatment for adrenal cancer in all stages. After surgery adjuvant chemotherapy is required. Mitotane is the most important drug in adrenal cancer chemotherapy. Mitotane’s mode of action is not entirely explained. Animal studies have shown that the substance exerts a direct cytotoxic effect on the cells of the adrenal cortex. This activity is selective, progressive and affects only the zona reticularis and fasciculata of the adrenal cortex. Mitotane inhibits cortisol synthesis by disrupting the chain of cholesterol. It has been suggested, that mitotane also affects the peripheral metabolism of steroids, especially of transcortin (CBG). This results in an increase of CBG blood concentration and a reduction of the amount of free hormones

Electric field and aging effects of uniaxial ferroelectrics Sr x Ba1-x Nb2O6 probed by Brillouin scattering

This study was supported in part by the Marubun Research Promotion Foundation and JSPS KAKENHI Grant Number JP17K05030.Static and dynamic heterogeneity of disordered system is one of the current topics in materials science. In disordered ferroelectric materials with random fields, dynamic polar nanoregions (PNRs) appear at Burns temperature and freeze into nanodomain state below Curie temperature (T C). This state is very sensitive to external electric field and aging by which it gradually switches into macrodomain state. However, the role of PNRs in such states below T C is still a puzzling issue of materials science. Electric field and aging effects of uniaxial ferroelectric Sr x Ba1-x Nb2O6 (x = 0.40, SBN40) single crystals were studied using Brillouin scattering to clarify the critical nature of PNRs in domain states below T C. On field heating, a broad anomaly in longitudinal acoustic (LA) velocity at low temperature region was due to an incomplete alignment of nanodomains caused by the interaction between PNRs. A sharp anomaly near T C was attributed to the complete switching of nanodomain to macrodomain state owing to the lack of interaction among PNRs. After isothermal aging below T C, the noticeable increase of LA velocity was observed. It was unaffected by cyclic temperature measurements up to T C, and recovered to initial state outside of a narrow temperature range above and below aging temperature.Japan Society for the Promotion of Scienc

The low-angle boundaries misorientation and lattice parameter changes in the root of single-crystalline CMSX-4 superalloy blades

The relationship between the angles of misorientation of macroscopic low-angle boundaries (LABs) and changes in the lattice parameter of the 0-phase around the LABs in the root of singlecrystalline (SX) turbine blades made of CMSX-4 superalloy were studied. The blades with an axial orientation of the [001] type were solidified using an industrial Bridgman furnace with a 3 mm/min withdrawal rate. X-ray diffraction topography, the EFG W-scan X-ray diffraction method, scanning electron microscopy, and Laue diffraction were used to study the thin lamellar samples with a thickness of 0.5 mm and orientation of the surface perpendicular to the [001] direction. It is found that in the areas with a width of a few millimetres around LABs, decreases in the lattice parameter of the 0-phase occur. These lattice parameter changes are related to the internal stresses of the 0-phase caused by local changes in the concentration of alloying elements and/or to the dendrite bending near the LABs. X-ray topography used on two surfaces of thin lamellar samples coupled with the lattice parameter measurements of the 0-phase near the LAB allows separating the misorientation component of LAB diffraction contrast from the component and visualising the internal stresses of the 0-phase

Ascites Index — a novel technique to evaluate ascites in ovarian hyperstimulation syndrome: a concept-proof study

 Objectives: Controlled ovarian hyperstimulation is an important step in infertility treatment. In some cases, however, ovar­ian hyperstimulation syndrome (OHSS) can occur. In its severe forms, ascites is likely to develop, associated with dyspnea. The aim of this study was to explore the usefulness of Ascites Index (AsI), a new tool for quantitative determination of ascites in patients with OHSS, to obtain data for planning further trials. Material and methods: Twelve patients with OHSS and ascites were included in the study. All patients were admitted to the hospital because of abdominal pain and dyspnea due to increasing ascites. Ultrasound measurements of ascites extent were performed in four external quadrants of the abdomen. Pockets of free fluid were measured. The obtained values were totaled, forming the Ascites Index (AsI), similarly to the amniotic fluid index. Because of dyspnea, paracentesis was performed in all cases. Results: Median AsI at which patients reported dyspnea was 29.0 cm (range 21.6–38.6 cm). At AsI values less than 21.6 cm, no dyspnea was observed in any of the 12 studied patients. To avoid complications, 2000 mL of ascitic fluid was collected in each patient. After paracentesis, range of AsI decreased to 12.1–14.5 cm. Conclusions: The proposed AsI seems to be a promising tool for estimating and monitoring the ascites extent in OHSS. It can be estimated using basic ultrasound equipment. AsI requires further studies for standardization and transferability to other causes of ascites

Defect Creation in the Root of Single-Crystalline Turbine Blades Made of Ni-Based Superalloy

An analysis of the defects in the vicinity of the selector–root connection plane occurring during the creation of single-crystalline turbine blades made of CMSX-6 Ni-based superalloy was performed. X-ray diffraction topography, scanning electron microscopy, and positron annihilation lifetime spectroscopy were used. Comparing the area of undisturbed axial growth of dendrites to the area of lateral growth concluded that the low-angle boundaries-like (LAB-like) defects were created in the root as a result of unsteady-state lateral growth of some secondary dendrite arms in layers of the root located directly at the selector–root connection plane. Additional macroscopic low-angle boundaries (LABs) with higher misorientation angles were created as a result of concave curvatures of liquidus isotherm in platform-like regions near selector–root connections. Two kinds of vacancy-type defects, mono-vacancies and vacancy clusters, were determined in relation to the LABs and LAB-like defects. Only mono-vacancies appeared in the areas of undisturbed axial growth. Reasons for the creation of macroscopic LABs and LAB-like defects, and their relationships with vacancy-type defects were discussed

Variation of crystal orientation and dendrite array generated in the root of SX turbine blades

The variation of the crystal orientation and the dendrite array generated in the root of the single-crystalline (SX) turbine blades made of CMSX-4 superalloy were studied. The blades with an axial orientation of the [001] type were solidified by the industrial Bridgman technique using a spiral selector at a withdrawal rate of 3 mm/min. The analysis of the crystal orientation and dendrite arrangement was carried out using scanning electron microscopy, X-ray di raction topography, and Laue di raction. It was found that the lateral growth of such secondary dendrite arms, which are defined as “leading” and grow in the root at first, is related to the rotation of their crystal lattice, which is the reason for creation of the low-angle boundary (LAB) type defects. The primary crystal orientation of the selector extension (SE) area determines the areas and directions of the lateral growth of the leading arms. Additionally, it was found that in the SE areas of the root, near the connection with the selector, the spatial distribution of the [001] 0 crystallographic direction has a complex wave-like character and may be related to the shape of the crystallization front

Ten years of anti-HPV vaccinations : what do we know?

Human papillomavirus (HPV) is one of the most important carcinogens in humans. Vaccines against HPV are now considered the first anti-cancer vaccinations. Since 2007, in many developed countries, there have been recommendations present for preventive vaccines against HPV. At present, the degree of implementation of these recommendations depends on a number of country-specific factors such as the health care system organization or the ways of funding. HPV vaccines are primarily to prevent the development of cervical cancer and other genital cancers. Therefore, only their long-term effectiveness can be measured, when a correspondingly large cohort of vaccinated teenagers reaches the age of the greatest incidence of these cancers. However, great care should be taken in assessing the results of vaccinations due to the possibility of misinterpretation and possible erroneous data. Undoubtedly, teenagers are the target population of HPV vaccines. However, vaccinating young sexually active women is also justified from an individual point of view. A 9-valent vaccine has been registered in the USA and in Europe - including Poland - as one of the three preventive vaccines. It is recommended to vaccinate women between 13 and 26 and men between 13 and 21, previously unvaccinated. It is also recommended to vaccinate men aged 26 years or less who have sexual relations with other men and people with reduced immunity, including HIV-positive people who have not been vaccinated previously

Heterogeneity of the dendrite array created in the root of cored SX turbine blades during initial stage of crystallization

The roots of cored single-crystalline turbine blades made of a nickel-based CMSX-4 superalloy were studied. The casts were solidified by the vertical Bridgman method in an industrial ALD furnace using the spiral selector and selector continuer situated asymmetrically in the blade root transverse section. Scanning electron microscopy, the Laue diffraction and X-ray diffraction topography were used to visualize the dendrite array and the local crystal misorientation of the roots. It has been stated that heterogeneity of the dendrite array and creation of low-angle boundaries (LABs) are mostly related to the lateral dendrite branching and rapid growth of the secondary and tertiary dendrites near the surface of the continuer–root connection. These processes have an unsteady character. Additionally, the influence of the mould walls on the dendrite array heterogeneity was studied. The processes of the lateral growth of the secondary dendrites and competitive longitudinal growth of the tertiary dendrites are discussed and a method of reducing the heterogeneity of the root dendrite array is proposed