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1.
Acta Crystallogr B Struct Sci Cryst Eng Mater ; 77(Pt 2): 225-231, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33843730

RESUMO

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.

2.
Am J Hum Biol ; 33(1): e23436, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32445509

RESUMO

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.


Assuntos
Desenvolvimento do Adolescente , Menarca , Comportamento Sexual , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Polônia , Fatores Socioeconômicos , Fatores de Tempo
3.
Acta Crystallogr B Struct Sci Cryst Eng Mater ; 76(Pt 3): 336-342, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32831254

RESUMO

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 dTs/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.

4.
Anthropol Anz ; 76(1): 37-47, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30648186

RESUMO

Objectives: The purpose of the study was to evaluate the relationship between BMI at menarche and selected growth spurt parameters, such as age at take-off of the pubertal growth spurt (ATO), age at peak height velocity (APHV), growth spurt duration (APHV-ATO), and the pubertal growth rate. Methods: The study group consisted of 243 girls aged 10-16 years. Several measurements of body height and weight have been taken for each girl during the girls' development (longitudinal study). Nutritional status has been assessed using the IOTF (Cole et al. 2000; Cole et al. 2007). Girls were asked about their age at menarche. To investigate the growth rate, the age at TO and PHV for each girl was calculated using AUXAL.3 software and a structural model JPA2. Statistical analyses were made in Statistica 12.0 using Kruskal-Wallis test Kruskal-Wallis test and multiple regression analysis. Results: The mean age at menarche for the entire group was 12.59 (Me = 12.52, Min = 9.9, Max = 16.2). There was a significant statistical relationship between the level of BMI and age at menarche. The age at menarche decreased significantly with increasing levels of nutritional status (H = 33.2, p < 0.001). Also, TO and PHV occurred earlier in girls with higher values of BMI indicator (TO: H = 12.25, p < 0.05; PHV: H = 12.25, p < 0.05). Conclusions: The level of nutritional status at the age of menarche is significantly related to growth and the rate of biological maturation in girls. Higher BMI at menarche is associated with an earlier occurrence of menarche, TO and PHV.


Assuntos
Índice de Massa Corporal , Menarca , Maturidade Sexual , Adolescente , Estatura , Criança , Feminino , Humanos , Estudos Longitudinais , Polônia , Puberdade
5.
J Biosoc Sci ; 51(5): 669-682, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30632477

RESUMO

The aim of this study was to examine the effect of economic changes in the Polish territories under Austrian partition at the end of the 19th and the beginning of the 20th centuries on the trend in adult body height, and to examine the effect of number of children in a family, as a socioeconomic factor, on the differences in heights of males and females. Data collected in a 1939 survey for a group of 350 Lemkos living in Polish lands under the Austrian partition were obtained from archive material. Individual data were obtained for body height and number of siblings, to calculate family size. Linear regression analysis confirmed an increase in body height in males by about 1.2 cm per decade over the period 1860 to 1922. The number of children in a family did not appear to influence the mean body height of men and women. The observed positive mean body height trend probably resulted from the improvement in the economic conditions in the Austrian sector over the survey period.


Assuntos
Estatura , Características da Família/história , Adulto , Criança , Feminino , História do Século XIX , História do Século XX , Humanos , Modelos Lineares , Masculino , Polônia , Fatores Socioeconômicos/história
6.
Anthropol Anz ; 75(3): 185-191, 2018 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-29892777

RESUMO

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.


Assuntos
Fatores Etários , Comportamento Sexual/estatística & dados numéricos , Mulheres , Adolescente , Adulto , Estudos de Coortes , Feminino , Humanos , Polônia , Fatores Socioeconômicos , Adulto Jovem
7.
Econ Hum Biol ; 28: 23-28, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29197239

RESUMO

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.


Assuntos
Menarca , Estudantes/estatística & dados numéricos , II Guerra Mundial , Adolescente , Peso Corporal , Pesos e Medidas Corporais , Feminino , Humanos , Masculino , Sobrepeso/epidemiologia , Polônia , Fatores Socioeconômicos , Universidades
8.
Am J Hum Biol ; 29(6)2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28688197

RESUMO

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, Poznan). 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.


Assuntos
Estatura , Peso Corporal , Estudos de Coortes , Feminino , História do Século XX , Humanos , Polônia , Estudos Retrospectivos , Estudantes , II Guerra Mundial , Adulto Jovem
9.
J Biosoc Sci ; 49(3): 364-379, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27724998

RESUMO

The aim of this study was to assess the impact of social and occupational status on the BMI of the gentry and peasantry in the Kingdom of Poland at the turn of 19th and early 20th centuries. Use was made of data on the height and weight of 304 men, including 200 peasants and 104 gentlemen, and 275 women, including 200 from the peasantry and 75 from the gentry. Gentlemen were characterized by a greater body height than peasants (169.40 cm and 166.96 cm, respectively), a greater body weight (67.09 kg and 60.99 kg, respectively) and a higher BMI (23.33 kg/m2 and 21.83 kg/m2, respectively). Landowners and intelligentsia had a greater BMI than peasants (23.12 kg/m2 and 24.20 kg/m2 vs 21.83 kg/m2, respectively). In the case of women, there were no statistically significant differences in mean height, weight and BMI by their social position, and in BMI by occupational status. Underweight occurred less frequently in the gentry and more frequently in the peasantry (0.97% and 2.04%, respectively). Overweight was five times more common in gentlemen than in peasants (26.21% and 5.10%, respectively). Differences in the BMI of gentlefolk and peasants resulted from differences in diet and lifestyle related to socioeconomic status.


Assuntos
Índice de Massa Corporal , Classe Social/história , Adulto , Estatura , Peso Corporal , Feminino , História do Século XIX , História do Século XX , Humanos , Masculino , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Polônia/epidemiologia , Inquéritos e Questionários , Magreza/epidemiologia
10.
Econ Hum Biol ; 21: 75-83, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26799228

RESUMO

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).


Assuntos
Índice de Massa Corporal , Militares/história , Características de Residência/história , Estatura , Peso Corporal , Alemanha/epidemiologia , História do Século XIX , História do Século XX , Humanos , Masculino , Militares/estatística & dados numéricos , Polônia/epidemiologia , Características de Residência/estatística & dados numéricos , Fatores Socioeconômicos , Adulto Jovem
11.
J Child Adolesc Psychopharmacol ; 25(9): 691-700, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26401547

RESUMO

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.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Obesidade/epidemiologia , Sobrepeso/epidemiologia , Magreza/epidemiologia , Índice de Massa Corporal , Peso Corporal , Criança , Pré-Escolar , Comorbidade , Estudos Transversais , Humanos , Estudos Longitudinais , Masculino , Polônia/epidemiologia , Prevalência , Estudos Retrospectivos
12.
Econ Hum Biol ; 18: 101-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26042531

RESUMO

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.


Assuntos
Alcoolismo/epidemiologia , Estatura , Índice de Massa Corporal , Pais , Adolescente , Criança , Feminino , Humanos , Masculino , Estado Nutricional , Polônia , Prevalência , Fatores Socioeconômicos , Magreza/epidemiologia
13.
Eur Child Adolesc Psychiatry ; 24(1): 41-53, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24633695

RESUMO

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.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Sobrepeso/epidemiologia , Adolescente , Peso ao Nascer , Criança , Estudos Transversais , Humanos , Recém-Nascido , Masculino , Obesidade/epidemiologia , Prevalência , Fatores de Risco
14.
J Biosoc Sci ; 46(5): 686-97, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24041152

RESUMO

Height is regarded as one of the indicators of environmental stress at population level, being an excellent barometer of standard of living. The aim of this study was to describe diversity in height among populations living in different regions of the Kingdom of Poland in terms of the economic factors in the second half of the 19th and early 20th century. This study examines the height of adult inhabitants from five guberniyas (provinces) of the Kingdom of Poland (Lomza, Warsaw, Radom, Kalisz and Plock) collected in the years 1897-1914 (N = 732 men, N = 569 women). Differences in average height of male and female inhabitants across the five guberniyas were examined using ANOVA and the Fisher's LSD (Least Significant Difference) test of multiple comparisons. Statistically significant differences in the height between the guberniyas were observed. Diversity in the economic development in the studied guberniyas of the Kingdom of Poland translated into differences in the height of their inhabitants. Moreover, an increase in mean height over time was noted.


Assuntos
Estatura , Classe Social/história , Adulto , Agricultura/história , Análise de Variância , Feminino , História do Século XIX , História do Século XX , Humanos , Masculino , Polônia , Federação Russa , Salários e Benefícios/história , Fatores Socioeconômicos
15.
Anthropol Anz ; 70(4): 455-70, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24620570

RESUMO

The aim of the study is to determine the influence of socioeconomic factors on age at menarche in Polish girls. Questionnaire data of 2016 girls were collected during the cross-sectional research. Within the socioeconomic variables parents' education, urbanization, number of children in the family and date of menarche were considered. To examine the effects of the analyzed socioeconomic factors on age at menarche, the analysis of variance and the Kaplan-Meier method were used. To estimate the mutual relations between the analyzed variables, the method of classification and regression trees (CART) was applied. The socioeconomic factors significantly affect age at menarche. The latest crossed threshold of puberty is observed in girls whose parents inhabit rural areas. Family size also affects age at menarche: girls from large families are the latest who have crossed the pubertal threshold. The method of classification and regression trees indicates that the most important predictive factor is the number of children in the family. The obtained results confirmed the complex effect of the analyzed variables. A factor that conditions occurrence of menarche most of all is the number of children in the family and then the urbanization degree of mother's place of residence. Further research is clearly required--especially research including analyses of mutual relations between variables and their complex effect.


Assuntos
Menarca , Adolescente , Fatores Etários , Criança , Feminino , Humanos , Estimativa de Kaplan-Meier , Polônia/epidemiologia , Fatores Socioeconômicos , Inquéritos e Questionários
16.
Coll Antropol ; 36(4): 1241-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23390817

RESUMO

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.


Assuntos
Adaptação Fisiológica/fisiologia , Núcleo Celular/fisiologia , Células Epiteliais/fisiologia , Esforço Físico/fisiologia , Esportes/fisiologia , Adolescente , Eletroforese/métodos , Humanos , Masculino , Mucosa Bucal/citologia , Mucosa Bucal/fisiologia , Adulto Jovem
17.
Acta Crystallogr B ; 67(Pt 2): 122-9, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21422611

RESUMO

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.

18.
Coll Antropol ; 31(4): 973-8, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18217444

RESUMO

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.


Assuntos
Equilíbrio Ácido-Base/fisiologia , Núcleo Celular/fisiologia , Exercício Físico/fisiologia , Adolescente , Eletroforese , Feminino , Homeostase , Humanos , Ácido Láctico/sangue , Mucosa Bucal/citologia
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