Technology and electrophysical properties of Mn4+, Sb3+, Dy3+ and W6+-doped Pb(Zr0.49Ti0.51)O3 ceramics

In paper three multicomponent PZT-type ceramics doped by Mn4+, Sb3+, Dy3+, W6+ have been prepared by the conventional mixed oxide method. The multicomponent PZT-type ceramic powders were synthetized by calcining route, while densification was carried out by pressureless sintering method. The paper presents XRD, SEM, EDS, dielectric and DC electric conductivity measurements of the multicomponent PZT-type ceramic samples. Conducted tests indicate obtained multicomponent PZT-type exhibit good dielectric properties giving the possibility for their use as actuators and piezoelectric transducers in modern micromechatronic and microelectronic applications

PZT-type ceramics doped with manganese, antimony, lanthanum and tungsten - technology and physical properties

The work three ceramic compositions based on PbZr0.49Ti0.51O3 doped with manganese (Mn), antimony (Sb), lanthanum (La) and tungsten (W) were obtained. The introduction of a set of admixtures was aimed at improving the sinterability of ceramic materials and optimizing its electrophysical parameters. Multi-component materials of the PZT-type with a general formula: Pb(Zr0.49Ti0.51)0.94Mn0.021Sb0.016LayWzO3 (where y from 0.008 to 0.012 and z from 0.012 to 0.014) were prepared by the conventional mixed oxide method. After mixing and drying the powder mixtures were calcined in air at 850°C for 4 h, while densification of the powders was carried out by the free sintering method at 1150°C for 2 h. The final steps of technology were grinding, polishing, annealing and putting silver paste electrodes onto both surfaces of the samples for electrical testing. XRD, SEM, EDS, dielectric, ferroelectric, piezoelectric properties and DC electrical conductivity of the obtained ceramic compositions were carried out. X-ray tests of the crystal structure conducted at room temperature have shown that all obtained the PZT-type materials were a single phase (perovskite type) without the presence of a foreign phase. Symmetry of the crystal lattice was identified as space group P4mm. Temperature dielectric studies have shown high values of dielectric permittivity and low dielectric loss. The presented physical properties of ceramic samples based on PZT confirm their predisposition for application in modern microelectronic and cromechatronic applications

Zaburzenia metabolizmu homocysteiny w stanie przedrzucawkowym

Summary Preeclampsia is one of the main causes of maternal and fetal mortality. We lack a reliable test that would identify the „at risk” group of pregnant women, thus allowing us to implement a specific prevention, management and treatment program. Recently, a number of theories regarding the pathophysiology of preeclampsia has been published. The role of vascular pathology as a result of an increase in homocysteine level is often mentioned. The aim of this paper is to review the current literature related to the pathology of preeclampsia and to evaluate the usefulness of assessment of homocysteine level and homocysteine metabolism disorders as a potential predictor of preeclamsia. Hiperhomocysteinemia is a known risk factor of cardiovascular diseases and hypertension. Different sources report a similar correlation between an increase in homocysteine level and the incidence of preeclampsia. As far as the topic of homocysteine in pregnancy is concerned, numerous questions and problems remain unanswered and unsolved. Although there exists a relationship between an increased values of homocysteine and the incidence of preeclampsia, there is not enough information about what group of patients should be included in the screening test to increase the rate of diagnosis and prevention of the most dangerous sequele.Streszczenie Stan przedrzucawkowy jest jedną z głównych przyczyn zgonów matek oraz umieralności okołoporodowej noworodków. Brakuje wiarygodnego testu pozwalającego zidentyfikować grupę ryzyka wśród ciężarnych celem wdrożenia adekwatnego postępowania, zapobiegania i leczenia. Na przestrzeni ostatnich lat pojawiło się w literaturze szereg teorii co do patomechanizmów doprowadzających do wystąpienia rzucawki. Podnosi się istotną rolę patologii naczyń łożyska, której przyczyną jest wzrost poziomu homocysteiny. Celem pracy jest przegląd literatury patologii stanu przedrzucawkowego pod katem oceny przydatności badania poziomu homocysteiny oraz zaburzeń jego metabolizmu jako potencjalnego predyktora wystąpienia stanu przedrzucawkowego. Hiperhomocysteinemia jest znanym czynnikiem ryzyka chorób układu krwionośnego i nadciśnienia. Liczne źródła podają podobną korelację między narastającym poziomem homocysteiny a występowaniem stanu przedrzucawkowego. Zagadnienie homocysteiny w ciąży nastręcza wiele pytań. Nie ma wiążących rekomendacji co do zasad postępowania. Wiele aspektów tego zagadnienia nadal pozostaje nie rozwiązanych. Chociaż wykazano związek między podwyższonymi wartościami homocysteiny a występowaniem stanu przedrzucawkowego to nie wiadomo jakimi badaniami objąć jaką grupę pacjentek aby istotnie wpłynąć na zwiększoną wykrywalność i zapobieganie występowania tych najpoważniejszych powikłań

Patogeneza i ryzyko zakażenia HIV u kobiet – przegląd aktualnego piśmiennictwa

Summary In Poland, as well as worldwide, HIV prevalence is increasing among women and their children. Women acquire the infection mainly through heterosexual contacts, while children get it from their mothers. Identification of the factors leading to the infection is essential in order to work out effective strategies for prevention of HIV transmission among women and children. In Polish literature there are no detailed clinical guidelines how to prevent mother-to-child HIV infection – a fact which is not without meaning as it put Poland in an unfavourable position when comparing to other European countries with a higher number of infected children. In this review authors present recent data concerning women susceptibility to HIV infection, virus pathogenesis, the role of co-infections with other pathogens, as well as the role of sex hormones on HIV infection risk. Authors hope that the information will help to establish Polish standards on prevention of HIV infection in women and their children, and that they will soon be put into practice.Streszczenie Zakażenie HIV na świecie, także w Polsce, coraz częściej dotyczy kobiet oraz ich dzieci. Najczęstszą drogą zakażenia HIV u kobiet są kontakty heteroseksualne, a u dzieci – zakażenia wertykalne. Poznanie czynników prowadzących do zakażenia HIV jest warunkiem niezbędnym do opracowania skutecznych strategii zapobiegania zakażeniom HIV/AIDS u kobiet oraz dzieci. W polskim piśmiennictwie brak jest szczegółowych rekomendacji dotyczących zapobiegania przeniesieniu zakażenia HIV od matki do dziecka, co przyczynia się do niechlubnej, znacznie wyższej w Polsce niż w innych krajach UE, liczby dzieci zakażonych HIV. W tym przeglądzie przedstawiono aktualne dane dotyczące podatności kobiet na zakażenie HIV, informacje dotyczące patogenezy zakażenia, roli współzakażeń innymi drobnoustrojami chorobotwórczymi w zwiększaniu ryzyka zakażenia HIV u kobiet oraz wpływ hormonów płciowych na ryzyko zakażenia HIV. Autorzy wyrażają nadzieję, że prezentowane informacje pomogą w szybkim opracowaniu krajowych rekomendacji w zakresie prewencji zakażeń HIV u kobiet oraz ich dzieci oraz ich wdrożeniu do codziennej praktyki klinicznej

Development of Harvesting Machines for Willow Small-Sizes Plantations in East-Central Europe

The production of plant biomass in small farms within the Central and Eastern European countries requires the application of agricultural machines adjusted to the scale of production. In the article, new machines for small-sized plantations of energy crops have been presented. Furthermore, the results of strength analysis of three-point linkage mower frame are presented by finite element method. The advantage of the proposed solutions is their simple construction, which is connected with low production cost and simple machine operation. The energy-crop harvesting machines are especially intended for small biomass producers in East-Central Europe, and the purchase of professional machines is financially inaccessible. The proposed machines are mounted in front or at the back of a typical farm tractor and the chipping units are power-take-off driven. The numerical simulation was carried out using finite element method to study the structural strength of a mower frame. All machine designs proposed by the Rzeszow University of Technology are legally protected by patents and utility models. The presented agricultural solutions have been worked out by authors and a part of them is still being developed in cooperation with biomass producers

Obrzezanie kobiet – nowy problem w praktyce lekarza ginekologa w krajach Unii Europejskiej?

Summary An increasing number of immigrants from countries practicing female genital mutilation (FGM) has begun to concern Europe as well. The aim of this article is to present recent medical data about FGM which, in the age of globalisation and migration of people, may become essential for gynaecologists working in Poland, but also those practising abroad.Streszczenie Rosnąca liczba imigrantów z krajów, w których wykonywane jest obrzezanie kobiet stanowi także europejski problem. Celem tego przeglądu literatury jest dostarczenie aktualnych informacji dotyczących obrzezania u kobiet (female genital mutilation – FGM), które w dobie globalizacji, migracji ludności mogą stać się niezbędne dla lekarzy ginekologów pracujących w Polsce, ale takle wyjeżdżających do pracy do innych krajów

Assessment of three-level selective perinatal care based on the analysis of early perinatal death rates and cesarean sections in Poland in 2008

Abstract Aim: The aim of the following work was to assess three-level selective perinatal care in Polish voivodeships in 2008 on the basis of the following parameters: birth rates as well as perinatal death rates, divided into three classes of neonatal weights, in hospitals on each of the three levels. The goal of selective perinatal care is, among other things, to diagnose threats to the mother and/or fetus and direct women with high-risk pregnancies to higher level obstetrics and neonatology clinics and units. The structure of a regional three-level perinatal care, as well as the rules and procedures governing the process of redirecting patients to different levels of perinatal care have been defined in great detail. Material and methods: Perinatal death rates analysis has been carried out on the basis of data received from Voivodeship Public Health Centers in sixteen voivodeships in Poland in 2008. The main document constituted MZ-29 form section X, modified by the authors and subdivided into levels of perinatal care. All data contained in the form have been verified: the numbers concerning birth and death rates as well as perinatal deaths and birth weight subgroups from given voivodeship hospitals. Statistic analysis was limited to the presentation of result tables and graphs within voivodeships. Results: Birth rates and perinatal death rates revealed that in the course of ten years the level of perinatal care, introduced gradually in Poland between the years 1997-1999, resulted in its improvement. Perinatal death rates decreased in the course of ten years from 9.5% in 1999 to 6.45% in 2008, i.e. by 0.3% annually. On the first level, the rate of neonates with very low birth weight, 500-999g, decreased by 5.5% and was 21.1% in 2008 and 36.6% in 1999, whereas on the third level, the birth rate in the same group (500-999g) increased by 12.7% and was 47.7% in 2008 and 35.5% in 1999. There is a growing and alarming tendency to perform cesarean sections. The increase amounted up to 1.2% annually (18.2% in 19999 and 30.5% in 2008), with vast differences among hospitals and voivodeships. In 2008 there were 28.4% of cesarean sections in level one-hospitals, 29.3% in level two-hospitals and 40.6% in level three-hospitals. Conclusions: The results of an overall decrease in perinatal deaths rate and an increase in birth rates in the group of neonates with very low birth weight on the third level are not satisfactory. Reintroduction of the program and strategy from the years 1995 and 1997 will enable us to improve the situation. Particularly this should be the case on the basic level perinatal care. In the context of three-level selective strategy

Regulation of apoptosis in endometrium preparation for menstruation or embryo implantation

Recent studies have presented apoptosis as the key mechanism of endometrial tissue reconstruction. Regulation of apoptosis leads to the menstruation or prepare the mucose layer for the implantation of the embryo. Thus, the factors controlling apoptosis determine proper endometrial preparation for blastocyst implantation. Among these factors, not only the progesterone but also embryonic factors (chorion gonadotropin) and those produced by endometrium affected by interaction with blastocyst (prolactin, IGFBP-1) plays the pivotal role

Radiation spectra and polarization in magnetar bursts

We present Monte Carlo simulations of radiative transfer in magnetar atmospheres. We include the effects of vacuum polarization, electron and proton scattering, and free-free absorption. Simulations are performed for the atmosphere model with the magnetic field perpendicular and also tilted with respect to the neutron star surface, and we show that the average spectrum does not strongly depend on the orientation of the magnetic field. We investigate the region of the parameter space where the vacuum absorption-like feature appears in the spectrum and we analyze the shape of the proton cyclotron line. Our results indicate that the existence of the vacuum polarization feature should be a general attribute of soft gamma-ray repeaters burst spectra, provided that the energy release takes place at the sufficiently dense region, and the atmosphere scaleheight is large enough. We discuss the existence of such a feature in recent observational data on these sources.Comment: submitted to Ap