Structure, ferroelasticity and Goldilocks zone phase transitions in C3H5N2Al(SO4)2·6H2O

The single crystal growth and sequence of reversible phase transition are described for C₃H₅N₂Al(SO₄)₂·6H₂O. Thermal and structural analyses combined with dielectric studies and optical observations revealed the structural phase transition at T₁ = 339/340 K (I↔II) and T₂ = 347/348 K (II↔III) on heating and cooling, respectively. Both phase transitions are of the first-order type. The symmetry changes from monoclinic to trigonal phase. At 293 K, the large crystals are usually divided into numerous domains of the ferroelastic type that disappear above T₁ on heating and reappear below T₁ on cooling. The domain structure pattern is characteristic for the transition between trigonal and monoclinic phases. The changes of entropy and clear increase of permittivity at T₁ provide evidence for the order-disorder character of this phase transition. The transition at T₂ seems to be displacive.

A closer look at superionic phase transition in (NH4)4H2(SeO4)3: impedance spectroscopy under pressure

The proton-conducting material (NH₄)₄H₂(SeO₄)₃ is examined to check whether its conductivity spectra are sensitive to subtle changes in the crystal structure and proton dynamics caused by external pressure. The AC conductivity was measured using impedance spectroscopy, in the frequency range from 100 Hz to 1 MHz, at temperatures 260 K < T < 400 K and pressures 0.1 MPa < p < 500 MPa. On the basis of the impedance spectra, carefully analyzed at different thermodynamic conditions, the p-T phase diagram of the crystal is constructed. It is found to be linear in the pressure range of the experiment, with the pressure coefficient value dT_s/dp = -0.023 K MPa^-1. The hydrostatic pressure effect on proton conductivity is also presented and discussed. Measurements of the electrical conductivity versus time were performed at a selected temperature T = 352.3 K and at pressures 0.1 MPa < p < 360 MPa. At fixed thermodynamic conditions (p = 302 MPa, T = 352.3 K), the sluggish solid-solid transformation from low conducting to superionic phase was induced. It is established that the kinetics of this transformation can be described by the Avrami model with an effective Avrami index value of about 4, which corresponds to the classical value associated with the homogeneous nucleation and three-dimensional growth of a new phase.

Time intervals between the age at menarche and the onset of sexual activity in Polish women born between 1959 and 2001

OBJECTIVES

The aim of this study was to assess time intervals between the age at menarche (AM) and age at sexual initiation (ASI) in Polish women born before and after the political transformation period in Poland.

METHODS

Participants were 518 women born between 1959 and 2001 in Poland. AM and ASI were based on self-report. Three birth cohorts were distinguished based on the year of birth: I (1959-1979), II (1980-1989), III (1990-2001). Three categories of AM were distinguished: early maturing (<12.0 years), average (12.0-13.0 years), and late maturing (≥14.0 years). Temporal intervals between AM and ASI were calculated.

RESULTS

Both AM and ASI decreased in subsequent birth cohorts, with the greatest changes observed in the women born after 1989. No significant differences in the time interval between AM and ASI were observed between birth cohorts. However, the time interval between AM and ASI differed by AM category (H = 74.16; P < .001). The longest time period between AM and ASI occurred in early maturing girls (7.13 years) and the shortest in late maturing girls (3.25 years).

CONCLUSIONS

Despite the transformation and decline in both AM and ASI, the time interval between these two characteristics remained stable. Significant differences in the time interval were found among women stratified by AM. The time interval between AM and ASI was longer in girls who matured early in comparison to those maturing late or at the average time.

Trends over time in age at sexual debut among Polish women and underlying socio-economic determinants

ABSTRACT

The aim of the study was to evaluate (1) changes over time in age at sexual initiation among Polish women and (2) underlying socio-economic determinants. 273 women born between 1975 and 1995 in Wielkopolska region (Poland) filled in a questionnaire of sexual behavior. The questionnaire included questions about the age of sexual initiation and women's socio-economic status such as place of residence, level of education, type of school, marital status. Database and statistical analyzes were performed using Statistica 10.0. Age of sexual initiation differed significantly among the cohorts of women stratified by birth cohort (H = 61.4, p < 0.001). In cohort I (born between 1970-1975), mean age of initiation was 18.97 years, in cohort II (1976-1980) 18.67 years, in cohort III (1981-1985) 18.53 years; cohort IV (1986-1990) 18.27 years, and cohort V (1991-1995) 16.41 years. Two socio-economic variables significantly affected the age of the sexual activity onset: the type of school and level of education. The mean age of sexual debut among Polish women has significantly decreased over the last 40 years, with the largest, statistically significant difference observed between the most recent cohort of women (born between 1991-1995) and the other cohorts (born between 1970-1990). The most significant socio-economic determinants of age at first sex were the type of school and level of education.

Age at menarche in Polish University students born before, during and after World War II: Economic effects

Although the relationships between economic conditions and biological variables over the past two centuries in Poland are reasonably well-documented, the influence of economic and political disruptions, including nutritional privation, during the years immediately before, during and shortly after World War II (WWII) has received less attention. This paper considers the association between age at menarche and body size of university students born before, during and after WWII and father's level of education, a commonly used indicator of family economic status in Poland. Subjects were 518 university students surveyed between 1955 and 1972, birth years 1931 through 1951. The sample was divided into three birth cohorts: before (n=237), during (n=247) and after (n=34) WWII. Age at menarche was compared among birth cohorts, and by weight status and father's level of education. Age at menarche increased slightly but significantly among women born during WWII (14.4 yrs) compared to those born before (14.2 yrs) and after (13.9 yrs) the war. Controlling for year of birth and age of the student, age at menarche was significantly earlier in overweight (13.42±0.35 yrs) than in normal weight (14.33±0.06 yrs) and thin (14.54±0.21 yrs) women. Adjusted mean ages at menarche in small samples of overweight women did not differ by father's level of education, and were earlier than corresponding ages of thin and normal weight women. Adjusted mean ages at menarche did not differ between thin and normal weight women with fathers having primary or no education, but were slightly later in thin than in normal weight women with fathers having a vocational, secondary or higher education. Although age at menarche was associated with father's level of education, young adult weight status was a somewhat more important correlate.

Body size of young adult Polish college-age women born before, during, and after WWII

OBJECTIVES

The aim of this study was to compare the young adult body size of Polish female university students born before, during, and after WWII.

METHODS

Age, height, and weight of 492 students measured between 1956 and 1972 were accessed from the Department of Anthropology archives (Adam Mickiewicz University, Poznań). The sample was divided into three birth year cohorts relative to WWII: before (n = 120), during (n = 196), and after (n = 176). Birth years spanned 1935 through 1952. BMI was calculated. Body size among birth cohorts was compared with age of the student and education level of the father as covariates (ANCOVA).

RESULTS

The birth cohorts differed significantly in height (P < .01), but not in weight and BMI. Women born during WWII were shorter than women born before and after the war; heights of latter cohorts did not differ. The trend for weight was similar, but differences were not significant. Birth cohorts did not differ in BMI.

CONCLUSIONS

Young adult heights of women born during WWII were shorter than the heights of women born before and immediately after the war, although differences were relatively small.

Filler's impact on structure and physical properties in polyester resin–oxide nanocomposites

Impact of nanosized oxide particles of titania (titanium dioxide, rutile) and silica–titania fumed compound on structure relaxation processes in nanocomposites of an orthophtalic unsaturated styrene cross-linked polyester resin has been experimentally studied using the thermal desorption mass spectroscopy, the dielectric spectroscopy, and the positron annihilation lifetime spectroscopy. All the nanocomposites showed unmonotonous variations in the thermal resistance, the dielectric permittivity and losses, and the annihilation rates for both positrons and ortho-positronium atoms with increasing filler’s loading. The nanoparticle-loading effects can be explained on the assumption that the oxide particles embedded into a cross-linked polyester resin induce rearrangements in its structure. Several mechanisms of particle–polymer interface interaction compete simultaneously and thus promote the alterations in molecular structure of the nanocomposites. The mechanisms may include both chemical and electrostatic fastening of polyester chains and styrene cross-links to the active surface sites, the destruction of the styrene cross-links, and redistribution of electron density in polymers. The features of the loading effects observed in the different nanocomposites can be ascribed to distinctions in both of active surface sites and intrinsic dielectric properties of the filling oxide particles.

Body mass index values of conscripts in the Polish lands under Prussian rule in the late 19th and early 20th centuries

The Body Mass Index (BMI) of conscripts from the Polish lands under Prussian rule and its causative factors and changes over time was to characterize. A total of 9965 conscripts aged 20 were examined. Differences in the mean BMI were tested using one-way analysis of variance ANOVA and Tukey's-test (post-hoc test). Factor analysis and multiple regression were employed. The highest BMI values characterized sons of peasants, workers and craftsmen, and the lowest, sons of intelligentsia: the difference for peasants/intelligentsia -0.59kg/m(2) (p=0.0004), and that for workers/intelligentsia and craftsmen/intelligentsia, 0.48 and 0.5kg/m(2) (p=0.0004 and p=0.0057, respectively). The difference in BMI of conscripts from the first and last birth cohorts was 0.61kg/m(2) (p=0.0001). The highest BMI values were noted in conscripts from villages (21.50kg/m(2)), and the lowest, in those from towns (21.15kg/m(2)) and cities (21.19kg/m(2)). The differences for village/town and village/city were statistically significant (p=0.0026 and p=0.0026, respectively). The BMI difference between Poles and Germans was 0.35kg/m(2) (higher value among Poles).

Attention-Deficit/Hyperactivity Disorder is Related to Decreased Weight in the Preschool Period and to Increased Rate of Overweight in School-Age Boys

OBJECTIVE

Previous studies have associated attention-deficit/hyperactivity disorder (ADHD) with growth deviations and obesity. However, available data regarding the growth of children with ADHD in their early childhood are insufficient. Therefore, we aimed to examine whether there are differences in body size between preschool boys with and without ADHD.

METHODS

The study used cross-sectional and retrospective longitudinal data concerning 112 boys with ADHD and a community-based sample of 308 boys without ADHD. The groups were homogeneous in terms of socioeconomic status, place of residence, term of birth, and birth weight. The average age of diagnosis was 8.3 years, and none of boys had been treated with stimulants before they were 7 years of age. Comparisons were made at the ages of 2, 4, and 6 years, for World Health Organization (WHO)-norm-standardized height, weight, body mass index (BMI), prevalence of underweight, overweight, and obesity. Separate analysis were made for the cross-sectional measurements of current body size.

RESULTS

Boys with ADHD at the age of 2 had significantly lower z scores for weight (t=-1.98, p=0.04) and BMI (t=-2.09, p=0.04), and at the age of 4 for weight (t=-2.05, p=0.04) than the boys from the control group. A significantly lower percentage of overweight/obesity was observed in boys with ADHD at the age of 2 in comparison with the control group. At the age of 6, boys with ADHD were underweight more often. Cross-sectional analysis of current body size showed that boys with ADHD had lower z scores for height (t=-3.08, p=0.002) and higher z scores (t=3.13, p=0.002) for BMI. Overweight was more frequent in this group.

CONCLUSIONS

Preschool boys with ADHD (age of 2-6 years) have a tendency toward lower body weight than their peers. But in subsequent phases of development, they are shorter and more frequently overweight than boys without ADHD, when place of residence, socioeconomic status, term of birth, birth weight, comorbid conditions, and treatment are controlled.

Electrophoretic mobility of cell nuclei (EMN index) as a biomarker of the biological aging process: Considering the association between EMN index and age

The present study examined whether a specific property of cell microstructures may be useful as a biomarker of aging. Specifically, the association between age and changes of cellular structures reflected in electrophoretic mobility of cell nuclei index (EMN index) values across the adult lifespan was examined. This report considers findings from cross sections of females (n=1273) aged 18-98 years, and males (n=506) aged 19-93 years. A Biotest apparatus was used to perform intracellular microelectrophoresis on buccal epithelial cells collected from each individual. EMN index was calculated on the basis of the number of epithelial cells with mobile nuclei in reference to the cells with immobile nuclei per 100cells. Regression analyses indicated a significant negative association between EMN index value and age for men (r=-0.71, p<0.001) and women (r=-0.60, p<0.001); demonstrating a key requirement that must be met by a biomarker of aging. The strength of association observed between EMN index and age for both men and women was encouraging and supports the potential use of EMN index for determining a biological age of an individual (or a group). In this study, a new attempt of complex explanation of cellular mechanisms contributing to age related changes of the EMN index was made. In this study, a new attempt of complex explanation of cellular mechanisms contributing to age related changes of the EMN index was made. EMN index has demonstrated potential to meet criteria proposed for biomarkers of aging and further investigations are necessary.

Growth and nutritional status of children from dysfunctional families with alcohol addicted parents in Poland

The study was aimed at assessment of impact of parents' alcohol addiction on growth and prevalence of underweight and overweight in their children. Two groups of subjects were compared: 80 children of alcohol addicted parents (ChAAP) aged from 7 to 14 years and reference group (RG) of 1000 children selected in terms of age and place of residence. Differences in z scores for height and Body Mass Index (BMI), prevalence of underweight and overweight were assessed. Families of ChAAP were characterized by: lower parents' education, higher unemployment rate, a greater number of children than in RG. The differences between ChAAP and RG in z scores for height (z scores: -0.54 vs. 0.45, t = -7.01, p < 0.001) and BMI (z scores: -0.61 vs. 0.29, t = -6.28, p < 0.001) remained significant when impact of the parents' employment (for height: F = 8.88, p = 0.003; for BMI: F = 21.90, p < 0.001) and the number of children (for height: F = 30.89, p < 0.001; for BMI: F = 21.89, p < 0.001) were controlled. Children raised in families with alcohol addicted parents were shorter and had lower BMI than children of the reference group. Underweight was more frequent in that group, and overweight and obesity were more rare. The observed differences seem to result from other factors than bad living conditions, e.g.: chronic post-natal stress, or adverse events during fetal development.

ADHD and overweight in boys: cross-sectional study with birth weight as a controlled factor

Population studies indicate a strong relationship between birth weight (BW) and body size in later life. However, BW as a variable was never accounted for in studies on the relationship between attention-deficit/hyperactivity disorder (ADHD) and overweight. This study aims to assess the relationship between ADHD and overweight with control of birth weight and other confounding factors. Prevalence of overweight was compared in clinical sample of 219 boys with ADHD and 396 boys without ADHD, aged 6-18 years. The following factors were controlled: BW, parents income and education level, place of residence, ADHD type, selected comorbid disorders and stimulant treatment. Overweight and obesity were diagnosed according to the criteria proposed by the International Obesity Task Force. Logistic regression analysis was used to estimate the association between ADHD and the prevalence of overweight and obesity. Boys with ADHD differed significantly from the control group in distribution of low BW (8.2 vs. 3.0 %, χ (2) = 8.23, p = 0.02). Low BW was associated with a lower prevalence of overweight than normal and high BW (0 vs. 12.14 %, χ (2) = 4.12, p = 0.04). Overweight was observed significantly more often in boys with ADHD (17.3 vs. 8.3 %, χ (2) = 11.23, p < 0.001) even after adjustment for BW and other variables (OR = 2.44, 95 % CI 1.38-4.29, p = 0.002) and after controlling for ADHD type, stimulant treatment and selected comorbid disorders. Independently to applied analysis, obesity was not associated with ADHD. Lower birth weight is over twice more often observed in boys with ADHD than in control group. Although this phenomenon may reduce the rate of overweight in the studied group, ADHD remains strongly associated with increased prevalence of overweight.

Ultrasonic Studies of Ferroelectric Phase Transition in Gly-H3PO3 Crystals

The temperature behaviour of the longitudinal and transverse ultrasound wave velocities and attenuation in the region of the ferroelectric phase transition (Tc = 225 K) of the glycine phosphite (Gly-H3PO3) crystals is studied. The obtained results are considered within the framework of phenomenological theory.

Adaptive changes of the electrophoretic mobility of cell nuclei (EMN) index in the intensive physical exercise of male rowers with different training experience

The aim of this study is to attempt to determine the relationship between the degree of the EMN index and the depth of changes of selected hormones and metabolic parameters as an effect of intensive physical exercise during the training process in male rowers. Juniors (N = 62; chronological age 16.4 y.o. SD = 1.14 y.; training experience 3.0 y.o. SD = 1.05 y.) and seniors (N = 27; chronological age 21.4 y. SD = 1.73 y.; training experience 5.5 y.o. SD = 1.10 y.), in the preparatory period of the training process, performed physical exercise of maximum intensity on a rowing ergometer. Acid-base balance parameters (pH, BE) and the concentration of lactic acid (LA) were determined as the result of physical exercise. Some selected hormones were also indicated (hGH, PrL and Prg) to show their exercise changes. A sample of buccal epithelium cells was taken from each of the male rowers, before and after the exercise, to evaluate the percentage of the EMN index by intracellular microelectrophoresis. A greater differentiation of metabolic changes during exercise was manifested in juniors than seniors. This was reflected in changes of acid-base balance parameters, exercise physiological parameters, hormone concentration and also in changes of the EMN index. These changes were probably dependent on deep metabolic processes of an acid character during exercise. This could prove a more stable homeostasis through more economical metabolic reactions in seniors as the effect of the training process, meaning that seniors were better adapted to heavy physical exercise than juniors.

Structural phase transitions in tetra(isopropylammonium) decachlorotricadmate(II), [(CH3)2CHNH3]4Cd3Cl10, crystal with a two-dimensional cadmium(II) halide network

Single crystals of tetra(isopropylammonium) decachlorotricadmate(II) as a rare example of a two-dimensional cadmium(II) halide network of [Cd(3)Cl(10)](n)(4-) have been synthesized and characterized by means of calorimetry and X-ray diffraction. The crystals exhibit polymorphism in a relatively narrow temperature range (three phase transitions at 353, 294 and 259 K). Our main focus was to establish the mechanism of these successive transformations. The crystal structure was solved and refined in the space group Cmce at 375 K (Phase I), Pbca at 320 K (Phase II) and P2(1)2(1)2(1) (Phase III) at 275 K in the same unit-cell metric. The structure is composed of face-sharing polyanionic [Cd(3)Cl(10)](4-) units which are interconnected at the bridging Cl atom into four-membered rings forming a unique two-dimensional network of [Cd(3)Cl(10)](n)(4-). The interstitial voids within the network are large enough to accommodate isopropylammonium cations and permit thermally activated rotations. While in Phase I isopropylammonium tetrahedra rotate almost freely about the C-N bond, the low-temperature phases are the playground of competition between the thermally activated disorder of isopropylammonium cations and stabilizing N-H···Cl hydrogen-bond interactions. The transition from Phase I to II is dominated by a displacive mechanism that leads to significant rearrangement of the polyanionic units. Cation order-disorder phenomena become prominent at lower temperatures.

The Electrophoretic Mobility of Cell Nuclei (EMN) index and changes in acid-base homeostasis under conditions of the intensive physical exercise

The relationship between the Electrophoretic Mobility of Cell Nuclei (EMN) index before and after super-maximal and maximal exercises and changes in physiological parameters associated with acid-base balance of the blood (pH, BE) and lactic acid concentration (LA) were examined in junior (N = 33, X = 15.6 y.o. SD = 1.16 y.), and senior (N = 10, X = 22.0 y.o. SD = 2.70 y.) female rowers. The following parameters: pH, BE and LA changed significantly (p < 0.05) from pre- to post-exercise status, while the EMN index changed only in junior female rowers under super-maximal conditions. Correlations between the EMN index and physiological parameters reflect the homeostatic disturbance associated with intensive exercise conditions. The decline in the EMN index appears to depend on the post-exercise changes of an organism's acidity. The results suggest that changes in the EMN index are associated with variation in physiological parameter, i.e. changes in acidity. We conclude that the EMN index reflects acid-base alterations and may be useful in evaluating systematic reactions to stress.

Fast-neutron OSL sensitivity of thallium-doped ammonium salts

The main problem in selecting suitable thermoluminescent (TL) materials for fast-neutron dosimetry is finding a material that is both tissue-equivalent and not damaged upon heating. Optically stimulated luminescence (OSL) avoids the need to heat the materials and allows the use of materials with a high content of hydrogen (responsible for 90% of the absorbed dose of fast-neutrons). The choice of studying the ammonium salts for their OSL properties was based on the calculation of their neutron kerma factor. A constant ratio of an ammonium salt's kerma coefficients to the tissue's kerma coefficients (in the fast-neutron range) is a prerequisite for a similar energy response to neutrons, i.e. tissue equivalency. The salts studied are NH4Br and (NH4)2SiF6 both doped with Tl+. This paper describes the OSL properties of Tl(+)-doped NH4Br and (NH4)2SiF6 after exposure to 14.5 MeV neutrons to explore their potential for developing new, tissue-equivalent OSL materials suitable for fast-neutron dosimetry. The relative neutron sensitivity, k, defined as the ratio of the sensitivity of the material to neutrons to its sensitivity to gamma rays, has been determined for 14.5 MeV neutrons and varies between k = 0.15 and k = 0.5. The latter value is a factor 2.5 higher than that found for known TL materials (k < or = 0.2). A drawback of these materials is the fast fading of the OSL signal.

Interferences in light deflection by ferroelastic domain walls

Deflection of light is studied in a crystal of glycine phosphite containing two twin walls. When the crystal is rotated in the incident laser beam, interferences are observed in both the direct beam and in the main deflected beam (A or B) for both polarizations of the incident light. The contrast is especially high, because the mutual tilt angle of the principal axes is close to 45 degrees in this twinned crystal. On this principle, fundamental-harmonic beam splitters could be built from as-grown twin crystals. Furthermore, the electrical modulation of the light deflected by ferroelectric-ferroelastic crystals can be now explained in terms of interference effects.