RESUMO
Four covalently-bonded tin(ii) coordination polymers, (1)-(4), were hydrothermally prepared in aqueous alkaline media by the reactions of SnSO4 with 1,2,4,5-benzenetetracarboxylic acid (1), 1,3,5-benzenetricarboxylic acid (2), 4-hydroxypyridine-2,6-dicarboxylic acid (3), and 1,3,5-cyclohexanetricarboxylic acid (4). All products were structurally authenticated by single-crystal X-ray diffraction, and the number of different tin centres and their oxidation states were confirmed by 119Sn Mössbauer spectroscopy. In addition, the comparison between experimental and simulated X-ray powder diffraction patterns confirmed the authenticity of the samples. Our crystallographic results for (1)-(4) show that the Sn(ii) centres are tetracoordinated and exhibit distorted disphenoidal geometries, corroborating the presence of one stereochemically active lone electron pair at each metal site. Products (1) and (2) display bi-dimensional polymeric structures, (3) exhibits a one-dimensional architecture, whereas (4) shows a remarkable three-dimensional coordination network. Hirshfeld surface and supramolecular analyses for the repeating units of (1)-(4) were also performed in order to identify structurally important non-covalent interactions.
RESUMO
BACKGROUND: There is scanty information about bone mineral density in newborns. Normal values are needed to assess the effects of diseases and drugs used during the neonatal period. AIM: To assess bone mineral density in normal newborns. PATIENTS AND METHODS: Total body bone mineral density was measured in 16 newborns with 39 +/- 1.2 weeks of gestational age, using a Norland dual photon densitometer. RESULTS: The mean weight of newborns was 3.366 +/- 325 g. Bone mineral content was 58.3 +/- 10.8 g and bone mineral density was 0.369 +/- 9.6 g/cm2. RESULTS: The availability of normal bone mineral content values in newborns will be useful for the assessment of conditions that affect bone mineralisation.
Assuntos
Absorciometria de Fóton/normas , Densidade Óssea , Feminino , Humanos , Recém-Nascido , Masculino , Padrões de ReferênciaRESUMO
Nickel-titanium instruments purportedly resist deformation and loss of sharpness better than do stainless steel instruments but may be more susceptible to breakage. The processes of wear and breakage of nickel-titanium and stainless steel instruments were examined. Sixty files of five types (12 each) and three manufacturers were used. All were used repeatedly in curved canals until failure or for a maximum of 22 minutes. Each instrument was examined with scanning electron microscopy both new (control) and at spaced intervals for evidence of wear and fatigue. All new instruments were of good quality. Stainless steel instrument tended to wear the most rapidly, and next were nickel-titanium rotary instruments; the most resistant to wear were nickel-titanium hand instruments. There were few instrument separations. In general, nickel-titanium (particularly hand) instruments resisted deterioration better than did stainless steel. Nickel-titanium rotary instruments (2 of 12) had the most breakage.
Assuntos
Ligas Dentárias , Instrumentos Odontológicos , Níquel , Aço Inoxidável , Titânio , Falha de Equipamento , Análise de Falha de Equipamento , Microscopia Eletrônica de Varredura , Propriedades de SuperfícieRESUMO
We present segregation distortions for the MNSs system and for the sex ratio found among 400 mother-newborn pairs, from the northern Area of Santiago and the middle-low and low socioeconomic strata. Three subsamples were taken: from the non private patients of the Clinical Hospital of the University of Chile; from the Hospital San José, a public hospital of this Area; controls of malformed newborns belonging to an international study from the Clinical Hospital of the University of Chile. In spite of the almost homogeneity of socioeconomic strata and area, the differences among these subsamples did not allow us to take them as only one sample. We found excess of heterozygous individuals for the MN locus, specially among mothers. Ss heterozygotes had a higher sex ratio than ss homozygotes. Several distortions could not be dealt with as having a regular pattern in the three subsamples. A possible technical error is discussed.
Assuntos
Variação Genética/genética , Sistema do Grupo Sanguíneo MNSs/genética , Chile , Feminino , Frequência do Gene/genética , Humanos , Recém-Nascido , Masculino , Mães , Fenótipo , Razão de Masculinidade , Classe SocialRESUMO
Canal Master instruments have a short, fluted cutting area and a small flexible shaft; they may be predisposed to rapid wear and breakage. This study examined new and used files as to tip, flute, and shaft design when new and with increasing time of canal preparation. One hundred files prepared 140 curved canals. Sizes #20, #40, and #60 files were examined unused and after 1, 3, 5, and 7 min of use. Evaluation was for uniformity when new and for deterioration and breakage with usage. The smaller sizes (#20 and #40) had some inconsistencies when new and were most predisposed to wear and breakage with time. Findings suggest that smaller files could have had improved quality control by the manufacturer. Also, they should be used with caution and discarded after short times of use in small, curved canals. This should minimize instrument separation and maximize cutting efficiency.
Assuntos
Preparo da Cavidade Dentária/instrumentação , Tratamento do Canal Radicular/instrumentação , Falha de Equipamento , Microscopia Eletrônica de Varredura , Controle de Qualidade , Propriedades de SuperfícieRESUMO
33 curved canals were prepared to quantify both the increase in canal area and predentin removal in the apical region. Compared were three different file designs/instrumentation techniques, that is "stepback" with K-flex file, "balanced force" with Flex-R file, and the Canal Master system. Following canal preparation and histological processing, cross-sections at 1 and 3 mm levels were examined using the Bioquant image analysis system. Results showed that, at the 3 mm leve, the mean increase in canal area and predentin removal showed no statistically significant difference (p > 0.05) between the techniques. At 1 mm, the step-back technique (with K-flex files) resulted in a significant increase in canal area and greater predentin removal than did the "balanced forces" (with Flex-R files) or the Canal Master system. However, although there were statistical differences, the actual differences were small; these may not translate to clinically significant differences in the 3 techniques.
Assuntos
Preparo da Cavidade Dentária/instrumentação , Tratamento do Canal Radicular/instrumentação , Preparo da Cavidade Dentária/métodos , Humanos , Tratamento do Canal Radicular/métodosRESUMO
This study describes the method and principles of fetal echocardiography, analyzing the technics and the utility of bidimensional mode, M mode and Doppler ultrasound on congenital fetal cardiopathies. The importance of early diagnosis in the structural alterations and fetal cardiac arrhythmias is emphasized.
Assuntos
Ecocardiografia Doppler/métodos , Ecocardiografia/métodos , Ultrassonografia Pré-Natal/métodos , Arritmias Cardíacas/congênito , Arritmias Cardíacas/diagnóstico por imagem , Ecocardiografia/instrumentação , Ecocardiografia Doppler/instrumentação , Feminino , Coração Fetal/anormalidades , Coração Fetal/diagnóstico por imagem , Cardiopatias Congênitas/diagnóstico por imagem , Humanos , Gravidez , Ultrassonografia Pré-Natal/instrumentaçãoRESUMO
Normal fetal hearth biometry is analyzed by echocardiography in 80 pregnant women with 20 and 40 gestational weeks. Intraventricular septum, aorta, left and right ventricular dimensions were obtained. All dimensions showing progression with gestational age.
Assuntos
Ecocardiografia/métodos , Coração Fetal/diagnóstico por imagem , Ultrassonografia Pré-Natal/métodos , Biometria/métodos , Ecocardiografia/instrumentação , Feminino , Idade Gestacional , Humanos , Gravidez , Valores de Referência , Ultrassonografia Pré-Natal/instrumentaçãoRESUMO
We present 119 echocardiographies in 90 high-risk pregnancies, 20 to 40 weeks gestational age. There were found 18 fetuses with abnormal examinations (20%), six of them with structural alteration (6.6%), and 14 arrhythmias (15.5%). The diagnostic correlation in structural alterations with a sensibility of 83% and 100% specificity, and 100% of sensibility and specificity in arrhythmias. The importance of antenatal diagnosis in cardiac malformations and arrhythmias is described.
Assuntos
Arritmias Cardíacas/diagnóstico por imagem , Ecocardiografia/métodos , Cardiopatias Congênitas/diagnóstico por imagem , Ultrassonografia Pré-Natal/métodos , Adulto , Arritmias Cardíacas/congênito , Arritmias Cardíacas/epidemiologia , Chile/epidemiologia , Ecocardiografia/instrumentação , Ecocardiografia/estatística & dados numéricos , Feminino , Cardiopatias Congênitas/epidemiologia , Humanos , Gravidez , Fatores de Risco , Ultrassonografia Pré-Natal/instrumentação , Ultrassonografia Pré-Natal/estatística & dados numéricosRESUMO
The step-back method of root canal preparation may not be suitable for endosonic files as they may be prevented from working efficiently within the apical region. This study determined the debris present in the apical portion of the canal after using three different endosonic instruments and compared the step-back versus the step-down technique; the latter involves initial preparation of the upper regions of the root canal which may reduce file constraint. Thirty-six teeth were prepared by either the step-back or step-down method using endosonic generators (magnetostrictive, piexoelectric, and sonic). Preparation times were standardized so that files were used for the same period. From scanning electron micrographs, debris removal was scored on a four-point scale by four clinicians. A log linear analysis showed that there was significantly less debris present with the step-down method using piezoelectric and sonic devices. More debris was present when files driven by a magnetostrictive instrument were used with the step-back method. This study showed that the step-down method may be useful when using certain types of endosonic generators.
Assuntos
Preparo da Cavidade Dentária/instrumentação , Preparo da Cavidade Dentária/métodos , Tratamento do Canal Radicular/instrumentação , Tratamento do Canal Radicular/métodos , Terapia por Ultrassom , HumanosRESUMO
A prospective study on 25 adolescent pregnant women was carried out. A single measurement of the systolic-diastolic ratio (S/D) was taken using continuous Doppler on arcuate arteries on both sides of the uterus. All measurements were taken after the 16th week of amenorrhea. The relationship between Doppler velocimetry and birthweight was established. Seven newborns were small for gestational age. The sensitivity of this method was 94.4% and specificity was 57.1%. Positive predictive value was 80.0% while negative predictive value was 85.0%. The importance of measuring both arcuate arteries and determining the site of placental insertion for proper interpretation of results is stressed.
Assuntos
Retardo do Crescimento Fetal/diagnóstico , Recém-Nascido Pequeno para a Idade Gestacional , Ultrassonografia Pré-Natal , Útero/irrigação sanguínea , Adolescente , Artérias/fisiologia , Velocidade do Fluxo Sanguíneo , Feminino , Humanos , Recém-Nascido , Valor Preditivo dos Testes , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Diagnóstico Pré-Natal , Estudos Prospectivos , Sensibilidade e Especificidade , Útero/diagnóstico por imagemRESUMO
Its related the development of two application in Computer Aided Instruction (CAI) in Medical Education with an Apple IIc and 128 K. The first using the PILOT for student; and the second a program of "Simulation of Labor Troubles" for interns and specialty training developed in BASIC. Am special point is the lower time training for the teacher with the PILOT. Its demonstrate the improvement through the qualification in relation to other evaluation in the same year and the relations with other questions during the same test.
Assuntos
Simulação por Computador , Instrução por Computador , Ginecologia/educação , Obstetrícia/educação , Avaliação Educacional , SoftwareRESUMO
Growth after menarche is described in 149 six to twenty year old girls from a growth and development follow-up study in a northern suburb of Santiago. Mean height at menarche and final adult height were obtained. The mean post-menarche growth was 6.40 +/- 2.70 cm. There was a large dispersion in post-menarche growth; three of them grew more than 15 cm and one 22 cm. We conclude that prediction of post-menarche growth is uncertain.
Assuntos
Estatura , Crescimento , Menarca/fisiologia , Adolescente , Adulto , Criança , Feminino , Humanos , Estudos Longitudinais , Fatores SocioeconômicosRESUMO
Healthy lying-in women admitted to the Clinical Hospital of the University of Chile, most of them belonging to the low socioeconomic of Santiago (Chile), showed a steady decrease in the plasma levels of total protein, albumin, beta-globulin, IgA, and IgM, and also a striking increase in the plasma level of alpha 1-Globulin. This trend was ascertained from december 1982 to august 1985, and the pattern of plasma protein change is similar to that found in human malnutrition. The observed changes in the immunoglobulins levels suggest a different behavior between IgM and IgA that do not cross the placenta and IgG that crosses it.
Assuntos
Proteínas Sanguíneas/análise , Imunoglobulinas/análise , Período Pós-Parto/sangue , Chile , Feminino , Humanos , Paridade , Gravidez , Desnutrição Proteico-Calórica/sangue , Fatores SocioeconômicosRESUMO
PIP: 1607 women were interviewed about their gyneco-obstetrical health in a survey of 469 randomly selected households in the province of Santiago, Chile. The dependent variables correspond to the frequency of gynecologic or obstetrical morbidity and demand for medical attention in 2 weeks of April, 1987. Independent variables were age, educational status, and health insurance coverage. 125 of the households were headed by uninsured persons. The average woman was 34.4 years old. 43.1% had 8 years or less of education, 42.6% had 9.12 years, and 14.2% had 13 or more years. 21 new cases of acute obstetrical or gynecological disorders were reported, including 15 of vulvovaginitis, 3 abortions, 1 bartholinitis, 1 intrahepatic cholestasis of pregnancy, and 1 urinary tract infection. There were 55 cases of chronic disorders, including 12 benign ovarian lesions, 8 dysmenorrheas, 8 uterine dystropias, 10 cases of menstrual disturbances, 1 of infertility, 4 benign cervical lesions, 5 benign uterine lesions, 2 pelvic inflammations, 2 cervical cancers, 2 breast cancers, and 1 ovarian cancer. Among the 1607 women, 11 had consulted for family planning in the 2 weeks, 25 for pregnancy, 22 for gynecological conditions, and 9 for postpartum care. 58.3% of the women aged 15-49 used a contraceptive method. The proportions of users of oral contraceptives and IUDs respectively were 62.5% and 37.5% for women under 20, 60% and 40% for women 20-29, 27% and 61% for women 30-39, and 15.1% and 60.6% for women 40-49. 28.2% of women over 15 had had a Pap test in the past year. The proportions of different age groups having Pap tests ranged from 2.0% for women under 20 to 46.7% for women aged 30-39. 3 women in the sample households had died in the past year of gyneco-obstetric causes, 1 of complications of childbirth and 2 of cervical cancer.^ieng