[Hepatitis B and pregnancy. Part 2. Nine practical issues about delivery and neonatal care]. / Hépatite B et grossesse. Partie 2. Neuf questions pratiques concernant l'accouchement et la prise en charge néonatale.

In France, the hepatitis B maternal-fetal transmission prevention strategy is based on serovaccination at birth. Serum therapy is to inject 30IU/kg of anti-HBs specific immunoglobulins of human origin in the first hours of life, which in practice corresponds to 1ml or 100IU. Vaccination should also be performed during the first hours of life, and a new injection should be performed at 1month and 6months. In infants less than 32weeks and/or less than 2kg, lower vaccine response leads to prescribe an additional injection at 2months. This serovaccination reduces the risk of mother to child transmission from 57 to 4 %. The failure risk factors of serovaccination are high maternal viral load (greater than or equal to 7 log) and/or the presence of HBeAg. The delivery route does not change the risk of maternal-fetal transmission of hepatitis B when serovaccination at birth was well conducted. Likewise, breastfeeding does not change the risk of maternal-fetal transmission of hepatitis B after serovaccination. It is recommended by WHO. During labor, the pH in utero should be done only when strictly necessary, the published data do not allow to conclude on the risk of transmission.

[Hepatitis B and pregnancy. Part 1. Thirteen practical issues in antenatal period]. / Hépatite B et grossesse. Partie 1. Treize questions pratiques en période anténatale.

In France, the prevalence of chronic hepatitis B is about 1% in pregnant women (usually asymptomatic carriers of HBsAg). The risk of maternal-fetal transmission of hepatitis B is particularly high when viral load measured by PCR is higher in mothers (above 7 log) or HBeAg is present. In case of maternal-fetal transmission of hepatitis B, the risk to the newborn of developing subsequent chronic hepatitis B is very high (90%), with long-term complications such as cirrhosis and hepatocellular carcinoma. The prevention of maternal-fetal transmission is based on systematic testing for hepatitis B during pregnancy, followed by serovaccination of the newborn at birth. If necessary, amniocentesis can be realised but will avoid the realization of a transplacental gesture. In case of high viral load, the establishment of a maternal antiviral treatment with lamivudine or tenofovir from 28SA can further reduce the risk of transmission. Given the low resistance it induces, tenofovir should be used preferentially.

Tissint martian meteorite: a fresh look at the interior, surface, and atmosphere of Mars.

Tissint (Morocco) is the fifth martian meteorite collected after it was witnessed falling to Earth. Our integrated mineralogical, petrological, and geochemical study shows that it is a depleted picritic shergottite similar to EETA79001A. Highly magnesian olivine and abundant glass containing martian atmosphere are present in Tissint. Refractory trace element, sulfur, and fluorine data for the matrix and glass veins in the meteorite indicate the presence of a martian surface component. Thus, the influence of in situ martian weathering can be unambiguously distinguished from terrestrial contamination in this meteorite. Martian weathering features in Tissint are compatible with the results of spacecraft observations of Mars. Tissint has a cosmic-ray exposure age of 0.7 ± 0.3 million years, consistent with those of many other shergottites, notably EETA79001, suggesting that they were ejected from Mars during the same event.

Oxygen isotope variation in stony-iron meteorites.

Asteroidal material, delivered to Earth as meteorites, preserves a record of the earliest stages of planetary formation. High-precision oxygen isotope analyses for the two major groups of stony-iron meteorites (main-group pallasites and mesosiderites) demonstrate that each group is from a distinct asteroidal source. Mesosiderites are isotopically identical to the howardite-eucrite-diogenite clan and, like them, are probably derived from the asteroid 4 Vesta. Main-group pallasites represent intermixed core-mantle material from a single disrupted asteroid and have no known equivalents among the basaltic meteorites. The stony-iron meteorites demonstrate that intense asteroidal deformation accompanied planetary accretion in the early Solar System.

What can the operator actually feel when performing a laparoscopy?

The designing of a laparoscopic simulator, particularly the parameterizing of a force feedback system, has drawn attention to the question of characterizing laparoscopic gestures and effecting quantitative measurement of the various interactions between the organs and the instruments used to operate in the case of animals. These measurements use an instrument previously developed by the authors' team. Laparoscopic gestures are characterized by a visual component and a haptic component. The visual component cannot, of course, be disregarded. The amplitude of the forces generated by interaction between organ and instrument in relation to that of the forces linked with other mechanical phenomena interfering with somesthesic information, such as friction of the operative instrument in the trocar or resistance of the abdominal wall to tilting movement, has led to a discussion about the extent of haptic components involved in the performance of laparoscopic gestures. After describing the measurement's device and the different forces applied on the surgical instrument, the authors describe the measurement of the rubbing strengths caused by the slippage of the instrument in the trocar and one of the elastic torques induced by the abdominal wall when the trocar in slanted. Comparison of values with those obtained during interactions with various organs shows that during some delicate surgical gestures, the influence of the instrument can disturb the haptic sensation. Interference of haptic sensation is greatest at maximal tilting angles and at maximal velocity of insertion and removal movement.

[Effect of laparoscopic trocar model on the quality of the movement: experimental study of friction]. / Influence du type des trocarts utilisés en coelioscopie sur la qualité du mouvement: étude expérimentale du frottement.

OBJECTIVE: To keep the pneumoperitoneum and the tightness of the abdominal and pelvic cavity during a laparoscopy, the sheaths of trocar are provided with a device (valvule, membranes etc.) inducing a friction during the handling of the instrument. The objective of this article is to analyse friction from different types of trocar's port. MATERIALS AND METHODS: We present here the experimental results obtained during a testing bench of three different trocar sheaths. The mechanism of tightness of the first trocar sheath is made of a fine membrane associated to a valve, of a thick membrane for the second trocar sheath, whereas the third trocar sheath is made of two membranes, a fine and a thick, associated to a valve. After reporting the experimental device and the analytic model adopted to describe the relationship between the measured physical parameters, we lay out our results. The identification of parameters of this model makes it possible to objectively compare the three trocars. RESULTS: Our results revealed that, under experimental conditions, the amplitude of friction was significantly lower with trocar's port provided with a valve and a fine membrane than with both other ports (fivefold weaker). DISCUSSION AND CONCLUSION: We evoke the importance of the possible disruption brought by these frictions while referring these values to those of other measurements concerning interactions between instrument and organs. These different behaviours of the material could have some consequences in choosing the tools for the performance of precise gestures.

MEP (Mars Environment Package): toward a package for studying environmental conditions at the surface of Mars from future lander/rover missions.

In view to prepare Mars human exploration, it is necessary to promote and lead, at the international level, a highly interdisciplinary program, involving specialists of geochemistry, geophysics, atmospheric science, space weather, and biology. The goal of this program will be to elaborate concepts of individual instruments, then of integrated instrumental packages, able to collect exhaustive data sets of environmental parameters from future landers and rovers of Mars, and to favour the conditions of their implementation. Such a program is one of the most urgent need for preparing human exploration, in order to develop mitigation strategies aimed at ensuring the safety of human explorers, and minimizing risk for surface operations. A few main areas of investigation may be listed: particle and radiation environment, chemical composition of atmosphere, meteorology, chemical composition of dust, surface and subsurface material, water in the subsurface, physical properties of the soil, search for an hypothesized microbial activity, characterization of radio-electric properties of the Martian ionosphere. Scientists at the origin of the present paper, already involved at a high degree of responsibility in several Mars missions, and actively preparing in situ instrumentation for future landed platforms (Netlander--now cancelled, MSL-09), express their readiness to participate in both ESA/AURORA and NASA programs of Mars human exploration. They think that the formation of a Mars Environment working group at ESA, in the course of the AURORA definition phase, could act positively in favour of the program, by increasing its scientific cross-section and making it still more focused on human exploration.

EXOCAM: Mars in a box to simulate soil-atmosphere interactions.

We present the principle of the EXOCAM chamber, devoted to the study of physical-chemical interactions between the atmosphere and the surface and subsurface in Mars conditions. The purpose of this experiment is to reach a better knowledge of the physical and chemical processes that altered the atmosphere-soil coupled system. We describe the scientific goals of EXOCAM, the multiple fields that will benefit from this experiment and the instrumentation that is devoted to the analysis of the results. We also give a description of the chamber and its main devices.

[SPIC: a training simulator for coelioscopic interventions with gynecologic purpose]. / SPIC: simulateur pédagogique d'interventions coelioscopiques à visée gynécologique.

There is much demand for laparoscopy training. We have developed a training simulator for initial training in gynecological laparoscopy. The simulator includes a mannequin with 3 located trocars, a PC and software for managing the graphical part of the training protocol. The objective is to learn how to achieve spatial localization and handle tools within the abdominal cavity. A series of exercises are proposed with increasing degree of difficulty. The simulator can be customized to simulate many different scenarios. The trainer must be present to provide an ultimate assessment of the trainee's experience. This new training tool cannot replace traditional surgical training but can help make it more efficient. The simulator is now being used by residents. Further technical developments are in progress to add further indispensable mechanical interactions (force feed back) to visualize the organ deformations and organ dissections within the abdominal cavity.

[Triploidies]. / Les triploïdies.

Triploidies are pregnancies that show a 69 chromosome karyotype. This chromosomal abnormality gives rise to early abortion in most cases. Triploid pregnancies, after the first three months, become molar pregnancies (molar changes inside the placenta with identifiable embryonic structures and a preeclampsia) or non molar pregnancies (isolated intauterin growth retardation). Several possibilities concerning the origin of the additional set of chromosomes exist: dispermy (the most common), diandry and digyny. The maternal and fetal clinical manifestations of this chromosomal abnormality are very diverse, which explains the difficulty of finding and recognizing this pathology. Mac Fadden's classification does not explain all the phenotypic triploid physiopathology. Formal diagnosis of triploidy depends on the fetal karyotype. The better the maternal prognosis is, the worst the fetal prognosis is. Postnatal life expectancy is not more than a few weeks. In most cases, maternal associated complications disappear with the molar evacuation. The risk of post molar tumor is discussed. However, good management of triploidy is based on an early diagnosis, before birth if that is possible.

Experimental dehydration of natural obsidian and estimation of DH2O at low water contents.

Water diffusion experiments were carried out by dehydrating rhyolitic obsidian from Valles Caldera (New Mexico, USA) at 510-980 degrees C. The starting glass wafers contained approximately 0.114 wt% total water, lower than any glasses previously investigated for water diffusion. Weight loss due to dehydration was measured as a function of experiment duration, which permits determination of mean bulk water diffusivity, mean Dw. These diffusivities are in the range of 2.6 to 18 X 10(-14) m2/s and can be fit with the following Arrhenius equation: ln mean Dw (m2/s) = -(25.10 +/- 1.29) - (46,480 +/- 11,400) (J/mol) / RT, except for two replicate runs at 510 degrees C which give mean Dw values much lower than that defined by the above equation. When interpreted according to a model of water speciation in which molecular H2O is the diffusing species with concentration-independent diffusivity while OH units do not contribute to the transport but react to provide H2O, the data (except for the 510 degrees C data) are in agreement with extrapolation from previous results and hence extend the previous data base and provide a test of the applicability of the model to very low water contents. Mean bulk water diffusivities are about two orders of magnitude less than molecular H2O diffusivities because the fraction of molecular H2O out of total water is very small at 0.114 wt% total water and less. The 510 degrees C experimental results can be interpreted as due to slow kinetics of OH to H2O interconversion at low temperatures.