Electron scattering by methanol and ethanol: a joint theoretical-experimental investigation.

We present a joint theoretical-experimental study on electron scattering by methanol (CH(3)OH) and ethanol (C(2)H(5)OH) in a wide energy range. Experimental differential, integral and momentum-transfer cross sections for elastic electron scattering by ethanol are reported in the 100-1000 eV energy range. The experimental angular distributions of the energy-selected electrons are measured and converted to absolute cross sections using the relative flow technique. Moreover, elastic, total, and total absorption cross sections for both alcohols are calculated in the 1-500 eV energy range. A complex optical potential is used to represent the dynamics of the electron-alcohol interaction, whereas the scattering equations are solved iteratively using the Padé's approximant technique. Our calculated data agree well with those obtained using the Schwinger multichannel method at energies up to 20 eV. Discrepancies at high energies indicate the importance of absorption effects, included in our calculations. In general, the comparison between our theoretical and experimental results, as well as with other experimental data available in the literature, also show good agreement. Nevertheless, the discrepancy between the theoretical and experimental total cross sections at low incident energies suggests that the experimental cross sections measured using the transmission technique for polar targets should be reviewed.

Nuevas aplicaciones en el diagnóstico ecográfico en 3D-4D en malformaciones fetales / New applications of 3D-4D ultrasonographic diagnosis of fetal malformations

Durante los tres últimos años han aparecido numerosas revisiones y nuevas modalidades ecográficas, tales como la tomografía con ultrasonidos, el VOCAL, el STIC, el modo inverso, el reverso, etc., que han revolucionado nuevamente las posibilidades de mejorar o completar el diagnóstico de las malformaciones fetales. El empleo de la tecnología 3D-4D puede aplicarse en la gran mayoría de las malformaciones y, combinado con la visión de la cinética fetal, ha mostrado que permite reducir el tiempo de exploración precisado para una completa visualización y mejor definición de las malformaciones

In the last 3 years, numerous revisions and new ultrasound modalities have emerged, such as ultrasound tomography, VOCAL, STIC, inverse mode, reverse mode, etc. These state of the art technologies have improved and/or completed the diagnosis of fetal malformations. These 3D-4D techniques can be applied to most malformations. In combination with fetal kinetics, this technology reduces the time spent in examination and improves visualization of malformations

Ecografía tridimensional y diagnóstico prenatal. Pasado, presente y futuro / Ultrasound 3D and prenatal diagnosis. Past, present and future

Sin dejar a un lado la ecografía bidimensional, la ecografía 3D combinada con la 2D permite la visualización de imágenes inaccesibles a la ecografía convencional. La ecografía 3D abre unas amplias perspectivas en el campo del diagnóstico prenatal, no sólo malformativo, sino en la confirmación de una extensa gama de marcadores de cromosomopatías, posicionándose además, firmemente, en el campo ginecológico, patología reproductiva y oncología. La última palabra sobre los avances tecnológicos de este modo ecográfico aún no se ha dicho (AU)

Prenatal diagnosis of sacrococcygeal teratomas by two- and three-dimensional ultrasound.

We suspected two fetuses of having sacrococcygeal teratomas following initial two-dimensional ultrasound scanning at 18 and 22 weeks' gestation. The fetuses were then scanned with three-dimensional multiplanar surface and three-dimensional orthogonal planar ultrasound to establish a definitive diagnosis. Although we made a presumptive diagnosis in both cases after initial two-dimensional scanning, with three-dimensional ultrasound we were better able to define the degree of involvement of the sacrum and other pelvic structures of prognostic importance.

Fetus acardius: two- and three-dimensional ultrasonographic diagnoses.

OBJECTIVE: To determine whether ultrasonographic detection of acardiac fetuses and diagnostic accuracy of related malformations improve with complementary use of two-dimensional ultrasonography, three-dimensional ultrasonography, and Doppler scanning. METHODS: Three pregnant women with multifetal gestations who were found to have discordant fetuses on initial two-dimensional ultrasonographic scanning were subsequently scanned with three-dimensional ultrasonography and color Doppler ultrasonography. RESULTS: Although the possibility of acardiac fetuses was entertained in all cases after two-dimensional ultrasonographic scanning, the diagnosis was confirmed, and the accuracy and extent of fetal malformations were established with three-dimensional ultrasonography and color Doppler scanning. Two of the women had twin gestations, and the third woman had a triplet gestation. Among the women with twin gestations, 1 donor twin had no abnormalities, and the other donor twin had a diagnosis of arthrogryposis and gastroschisis. The woman with triplets had 1 acardiac fetus; the donor fetus was anencephalic; and the third fetus had alobar holoprosencephaly. CONCLUSIONS: Complementary use of two-dimensional ultrasonography, three-dimensional ultrasonography, and color Doppler scanning improves diagnostic accuracy and the ability to evaluate the extent and severity of organ compromise in pregnancies complicated by acardiac fetuses.

Two- and three-dimensional ultrasound in malformations of the medullary canal: report of four cases.

A comparison between two-dimensional (2D), and three-dimensional (3D) ultrasonography was made in four fetuses diagnosed with neural tube defect (NTD) in the first half of pregnancy. 3D ultrasonography (orthogonal and multiplanar systems) proved to be an excellent complement to 2D, particularly when using orthogonal planes. When using the 3D multiplanar surface imaging system, excellent images of the malformations can be rapidly obtained.

Abdominal wall defects: two- versus three-dimensional ultrasonographic diagnosis.

We diagnosed 12 cases of abdominal wall defects. The cases diagnosed occurred in 6 fetuses with omphalocele, 3 with gastroschisis, 2 with prune-belly syndrome, and 1 with pentalogy of Cantrell. Except for 1 case of gastroschisis first diagnosed on the basis of three-dimensional ultrasonography at 14 weeks' gestation, all cases were first detected by two-dimensional transabdominal ultrasonography and then reevaluated with three-dimensional ultrasonography using multiplanar and orthogonal plane modes. Although the original diagnosis was accurate on the basis of two-dimensional ultrasonography in 11 of 12 cases, additional information was obtained by three-dimensional scanning in all cases. Our experience suggests that in cases in which abdominal wall defects are first detected by two-dimensional ultrasonographic scanning, the additional information gained by complementary three-dimensional ultrasonographic scanning can be useful for more-efficient counseling and postnatal therapeutic planning.

Thanatophoric dysplasia: ultrasound diagnosis.

Six pregnant women with singleton fetuses were referred to our Prenatal Diagnostic Centers because of an initial diagnosis of intrauterine growth restriction (n = 4) or short femoral length (n = 2). We first examined the patients with two-dimensional (2D) ultrasonography (US), and then with three-dimensional (3D) US, and arrived at a definitive diagnosis of thanatophoric dysplasia. Although in experienced hands a diagnosis of thanatophoric dysplasia can be made with 2D US before the 24th week of gestation, our experience suggests that 3D US is a valuable complement to 2D US for the evaluation of fetuses with skeletal dysplasias.

A problemática dos condilomas atípicos do cérvix / The problem of atypical cervical condylomas

Com base em uma revisäo dos casos de condilomas cervicais estudados clinicamente, colpo-cito-histologicamente e mediante auto-radiografia e microscopia eletrônica, investigou-se o problema dos condilomas atípicos. Descrevem-se as últimas variedades de HPV descobertas, a relaçäo dos condilomas com as CIN e seu possível diagnóstico diferencial. Finalmente, destaca-se a importância do estudo das células de Langerhans e dos mercadores imunológicos para o diagnóstico dos condilomas atípicos

Diagnostico de hidrotorax fetal bilateral pela ultra-sonografia. / Bilateral fetal hydrothorax diagnosis by the ultrasound

Um caso raro de hidrotorax fetal bilateral foi diagnosticado pela ultra-sonografia gray-scale no terceiro trimestre da gravidez em paciente sem queixa e aparentemente normal. O neonato morreu menos de trinta minutos depois do parto insuficiencia respiratoria aguda