SUMMARY The child's skin microcirculation (MCC) undergoes changes from the first days of life until adolescence. Through video capillaroscopy (VC), in vivo and non-invasive visualization of the CCM is accessed in children of any age. The site of the election is the nail fold of the fingers of the hands. The capillary loops arranged in a crown over the nail matrix and the superficial vascular plexus are observed. The newborns present a primitive network, which later evolves reaching around 10 years the parameters similar to the adult. There are structural differences in MCC if the findings in children are compared with those of adults. In children the capillary density per linear millimeter is lower, the tortuosity index is higher, the superficial vascular plexus is more visible and bizarre capillary forms are found Knowledge of the parameters of MCC preserved in children will be of great importance in the diagnostic exploration of pathologies that affect this vascular territory such as rheumatic diseases.

RESUMEN En el niño, la microcirculación cutánea (MCC) experimenta cambios desde sus primeros días de vida hasta la adolescencia. Mediante la video capilaroscopia (VC), se puede acceder a la visualización in vivo e incruenta de la MCC, en niños de cualquier edad. El sitio de elección es el pliegue peri ungular de los dedos de las manos. Se observan las asas capilares, dispuestas en corona sobre la matriz peri ungular y el plexo vascular superficial. Los recién nacidos presentan una red primitiva. Posteriormente, evolucionaalcanzando alrededor de los 10 años, los parámetros similares al adulto.El conocimiento de los parámetros de la MCC preservada en niños,será de gran importancia en la exploración diagnóstica de las patologías que afectan este territorio vascular, como las enfermedades reumáticas.

Nailfold capillaroscopy is a technique to visualize the skin microcirculation in vivo. This is of the utmost importance to establish the differential diagnosis between primary and secondary Raynaud. We hereby present the capillaroscopic image of the alterations, both structural and functional, detected in a female adolescent with Raynaud's phenomenon. In the next months the patient developed a systemic lupus erythematosus. The presence of these prior to the development of lupus disease is rare findings.

La capilaroscopía periungular es una técnica de estudio, de la microcirculación cutánea in vivo. Es de elección en el diagnóstico diferencial entre Raynaud primario y secundario. Presentamos la descripción de los hallazgos capilaroscópicos mediante imágenes, en una adolescente que padece fenómeno de Raynaud. Se hallan alteraciones estructurales y funcionales de los capilares. En los meses posteriores la paciente desarrolla lupus eritematoso sistémico. La presencia de estos hallazgos previos al desarrollo de enfermedad lúpica, no es frecuente.

The article discusses the nature of the gravimetric survey as applied and used in dolomite stability investigations on areas underlain by the Chuniespoort Group in South Africa. A short discussion is given on the gravimetric survey procedure along with its uses and alternative methods. Finally, two case studies illustrate the application of the method on a high-density survey grid spacing in comparison with three-dimensional geological modelling based on the lithology and karst weathering horizons of the Chuniespoort Group deduced from rotary percussion borehole data and limited rotary core borehole data. The two different case studies highlight the advantages and limitations of the high-density gravimetric survey. The first case studies shows that the high-density gravimetric survey can be applied to great effect to sites with a complex, variable profile, provided the grid spacing of the survey is adequate to identify the sub-surface features. Simultaneously, the findings of the second case study illustrate how the method has exactly the same limitations as regular gravimetric surveys if the scale of the grid is not compatible with sub-surface conditions.

Synthetic hydroxyapatite, Ca10(PO4)6(OH)2, is a biomaterial used to reconstruct damaged bone tissue or to recover protheses. Indeed, the chemical composition and structure is similar to the mineral phase contained in the scheleton. This similarity favors the formation of bonds with the bone, it becomes then a biocompatible material. Hydroxyapatite may be obtained from bones, but, nowadays, it is synthesized through various chemical procedures such as: solid state, sol-gel, double decomposition, neutralization and hydrothermal reactions. The hydrothermal method is the most employed due to its simplicity but it presents the disadvantage of the required high temperatures (600-1000 °C) and very long times (2-14 days) to obtain hydroxyapatite crystals. A recent improvement in the synthesis of solids as pillared clays, hydrotalcites or zeolites has been the microwave irradiation, as it reduces time and crystallization temperature. In this work, hydroxyapatite is synthesized in presence of microwave irradiation in an autoclave at 80 °C for 10 minutes, 1 atm and 200 W power. The influence of pH is studied. The microwave treatment reduced considerably the synthesis time if compared to the other methods. The properties, texture and morphology of the obtained compounds were significantly modified.

La hidroxiapatita sintética, Ca10(PO4)6(OH)2, es un biomaterial que se emplea para reconstruir tejido óseo dañado o como recubrimiento de prótesis, ya que su composición química y su estructura se asemejan a la fase mineral contenida en el esqueleto; esta similitud favorece la formación de enlaces con el hueso, siendo por consiguiente un material biocompatible. La hidroxiapatita se puede obtener a partir de huesos, pero hoy en día se sintetiza mediante diferentes procedimientos químicos, como las reacciones en estado sólido, el método sol-gel, la reacción por doble descomposición, la neutralización o el método hidrotérmico. El método hidrotérmico es el más empleado por su simplicidad, pero los inconvenientes del proceso son las altas temperaturas (600-1000 ºC) y los largos tiempos (2-14 días) necesarios para obtener los cristales de hidroxiapatita. Por otro lado, una mejora novedosa en la síntesis de sólidos como las arcillas pilareadas, las hidrotalcitas o las zeolitas es la irradiación con microondas que tiene la particularidad de reducir los tiempos y las temperaturas de cristalización. En este trabajo se presenta la síntesis de hidroxiapatita por medio de irradiación con microondas en una autoclave a 80 ºC, por 10 minutos, 1 atm y una potencia de 200 W. Además, se estudió la influencia del pH en la preparación. El tratamiento con microondas redujo considerablemente el tiempo de síntesis en comparación con otros métodos y las propiedades, la textura y la morfología de la hidroxiapatita obtenida resultaron ser significativamente diferentes.

In all mammalian species studied to date, sperm cells are arrested in the caudal isthmus before ovulation to form an oviductal reservoir. When ovulation occurs, discrete numbers of sperm are released from this region and ascend to the ampulla where fertilization normally occurs. Experimental evidence indicates that the sperm reservoir is instrumental in delivering the appropriate number of sperm in the correct physiological state for normal fertilization. In this paper, we present a comprehensive review of the sperm reservoir formation and functions in mammals. Sperm reservoir manipulation as a potential tool to improve reproductive performance is also discussed