Thermoelectric properties of double-substituted tetrahedrites Cu12-xCoxSb4-yTeyS13.

Tetrahedrites, a class of earth-abundant minerals, exhibit extremely low thermal conductivity values making them promising candidates for thermoelectric applications at high temperatures. Herein, we extend investigations on these materials to specimens substituted on both the Cu and Sb sites by reporting on the thermoelectric properties of polycrystalline Cu12-xCoxSb4-yTeyS13 in a wide range of temperatures (2-700 K). All prepared samples exhibit p-type heavily-doped semiconducting behavior with relatively low electrical resistivity values. These substitutions have little influence on the thermal conductivity, which remains very low in the whole temperature range (∼0.7 W m(-1) K(-1)). Although the double-substituted samples exhibit higher ZT values with respect to the parent tetrahedrite Cu12Sb4S13, the maximum ZT of 0.80 reached at 700 K for (x,y) = (0.82, 0.41) remains comparable to the values obtained in compounds solely substituted with Co or Te.

From crystal to glass-like thermal conductivity in crystalline minerals.

The ability of some materials with a perfectly ordered crystal structure to mimic the heat conduction of amorphous solids is a remarkable physical property that finds applications in numerous areas of materials science, for example, in the search for more efficient thermoelectric materials that enable to directly convert heat into electricity. Here, we unveil the mechanism in which glass-like thermal conductivity emerges in tetrahedrites, a family of natural minerals extensively studied in geology and, more recently, in thermoelectricity. By investigating the lattice dynamics of two tetrahedrites of very close compositions (Cu12Sb2Te2S13 and Cu10Te4S13) but with opposite glasslike and crystal thermal transport by means of powder and single-crystal inelastic neutron scattering, we demonstrate that the former originates from the peculiar chemical environment of the copper atoms giving rise to a strongly anharmonic excess of vibrational states.

Invited article: A round robin test of the uncertainty on the measurement of the thermoelectric dimensionless figure of merit of Co0.97Ni0.03Sb3.

A round robin test aiming at measuring the high-temperature thermoelectric properties was carried out by a group of European (mainly French) laboratories (labs). Polycrystalline skutterudite Co0.97Ni0.03Sb3 was characterized by Seebeck coefficient (8 labs), electrical resistivity (9 labs), thermal diffusivity (6 labs), mass volume density (6 labs), and specific heat (6 labs) measurements. These data were statistically processed to determine the uncertainty on all these measured quantities as a function of temperature and combined to obtain an overall uncertainty on the thermal conductivity (product of thermal diffusivity by density and by specific heat) and on the thermoelectric figure of merit ZT. An increase with temperature of all these uncertainties is observed, in agreement with growing difficulties to measure these quantities when temperature increases. The uncertainties on the electrical resistivity and thermal diffusivity are most likely dominated by the uncertainty on the sample dimensions. The temperature-averaged (300-700 K) relative standard uncertainties at the confidence level of 68% amount to 6%, 8%, 11%, and 19% for the Seebeck coefficient, electrical resistivity, thermal conductivity, and figure of merit ZT, respectively. Thermal conductivity measurements appear as the least accurate. The moderate value of the temperature-averaged relative expanded (confidence level of 95%) uncertainty of 17% on the mean of ZT is essential in establishing Co0.97Ni0.03Sb3 as a high temperature standard n-type thermoelectric material.

Successful management of a severe combat penetrating brain injury.

We report the case of successful management of a transcranial penetrating high-energy transfer injury in a 20-year-old soldier. The bullet traversed both cerebral hemispheres and lacerated the superior sagittal sinus rendering him unconscious. We detail the care received at all stages following injury from 'Buddy Aid' on the battlefield, resuscitation by a forward medical team through to prompt neurosurgery within 2 h of injury. Subsequent aeromedical evacuation and continuing aggressive critical care has allowed the patient to survive with acceptable neurological impairment after what is generally considered an unsurvivable injury.

[Management of penetrating abdominal trauma: what we need to know?]. / Prise en charge des traumatismes pénétrants de l'abdomen : des spécificités à connaître.

Penetrating traumas are rare in France and mainly due to stabbing. Knives are less lethal than firearms. The initial clinical assessment is the cornerstone of hospital care. It remains a priority and can quickly lead to a surgical treatment first. Urgent surgical indications are hemorrhagic shock, evisceration and peritonitis. Dying patients should be immediately taken to the operating room for rescue laparotomy or thoracotomy. Ultrasonography and chest radiography are performed before damage control surgery for hemodynamic unstable critical patients. Stable patients are scanned by CT and in some cases may benefit from non-operative strategy. Mortality remains high, initially due to bleeding complications and secondarily to infectious complications. Early and appropriate surgery can reduce morbidity and mortality. Non-operative strategy is only possible in selected patients in trained trauma centers and with intensive supervision by experienced staff.

[Low-pressure tamponade mimicking cholecystitis]. / Tamponnade à pression basse mimant une cholécystite.

Low-pressure tamponade is rare and little known with difficult clinical recognition. We report a case of this pathology in a patient admitted for abdominal severe sepsis. Pericardiocentesis led to identification of Salmonella typhimurium pericarditis. This case report emphasizes the clinical recognition difficulty and the interest of early fast echography in case of hemodynamic emergency.

[Antibodies against high frequency antigen and total knee replacement]. / Anticorps antipublic et prothèse totale de genou.

We report the perioperative management of a woman expressing an antibody against high frequency red cell antigen (anti-Kel4 antibody anti-kpb) who was scheduled for a total knee replacement. A specific strategy was designed to afford this major orthopedic surgery, considering specially the occurrence of unusual bleeding higher than the average bleeding assessed in our hospital in this indication. The transfusion of incompatible red cells may be responsible for acute hemolytic reaction. An autologous transfusion program, including cryopreservation, erythropoietin and iron support, was provided. Three autologous red cells units were collected before surgery. Compatible homologous red cells units were also available at the French bank for rare blood groups. We report logistical and medical problems that have occurred during the perioperative period.

Laser fragmentation in liquid medium: a new way for the synthesis of PbTe nanoparticles.

Synthesis of PbTe nanoparticles has been performed by pulsed laser fragmentation of PbTe micron-sized powders in distilled water with a Nd:YAG laser. The influence of various experimental parameters (wavelength, treatment duration, and output energy) on the yield of fragmentation, the size and the crystallographic structure of the nanoparticles produced has been investigated. Characterization of the nanopowders was performed by X-ray diffraction analyses and transmission electron microscopy observations. Thanks to a careful control of the synthesis parameters, PbTe nanoparticles with an average diameter close to 6 nm and exhibiting a sharp distribution in size have been produced.

[Understanding mistake-proofing]. / Comprendre la notion de détrompage.

The mistake-proofing concept often refers to physical devices that prevent actors from making a wrong action. In anaesthesiology, one immediately thinks to specific design of outlets for medical gases. More generally, the principle of mistake-proofing is to avoid an error, by placing knowledge in the world rather than knowledge in the head. As it often happens in risk management, healthcare has received information transfers from the industry. Computer is changing the concept of mistake-proofing, initially based on physical design, such as aerospace and automotive industry. The mistake-proofing concept may be applied to prevention, detection, and mitigation of errors. The forcing functions are a specific part of mistake-proofing: they prevent a wrong action or they force a virtuous one. Grout proposes a little shortcut to identify mistake-proofing devices: "If it is not possible to picture it in action, it is probably not a mistake-proofing device".

Crystal structure and transport properties of Ba8Ge43square3.

The single phase clathrate-I Ba(8)Ge(43)square(3) (space group Ia3d (no. 230), a = 21.307(1) A) was synthesized by quenching the melt between cold steel plates. Specimens for physical property measurements were characterized by microstructure analysis and X-ray diffraction on polycrystalline samples as well as single crystals. Transport properties including thermopower, electrical resistivity, thermal conductivity and specific heat were investigated in a temperature range of 2-673 K. The electrical resistivity exhibits a metal-like temperature dependence below 300 K turning into a semiconductor-like behaviour above 300 K. The analysis of the specific heat at low temperature indicates a finite density of states at the Fermi level, thus corroborating the metallic character below 300 K. The temperature dependence of the specific heat was modelled assuming Einstein-like localized vibrations of Ba atoms inside the cages of the Ge framework. A conventional crystal-like behaviour of the thermal conductivity with a low lattice contribution (kappa(l)(300 K) = 2.7 W m(-1) K(-1)) has been evidenced.

High temperature thermoelectric properties of Mo3Sb(7-x)Te(x) (0.0≤x≤1.8).

Polycrystalline Mo(3)Sb(7-x)Te(x) samples with nominal Te concentrations of x=0.0, 0.3, 1.0, 1.6 and 2.2 have been synthesized by a powder metallurgical route. High temperature thermoelectric properties measurements including thermopower (300-900 K), electrical resistivity (300-800 K) and thermal conductivity (300-1000 K) were carried out. The temperature and compositional variations of the thermopower can be satisfactorily explained by assuming a single parabolic band model with dominant acoustic phonon scattering. However, such a simple model fails to describe the electronic thermal conductivity for low Te concentration. The dimensionless figure of merit, ZT, increases on increasing both the temperature and the Te content to reach a maximum value of 0.3 at 800 K that can be extrapolated to ∼0.6 at 1000 K for Mo(3)Sb(5.4)Te(1.6).

[Mamba envenomation in mainland France: management of exotic envenomations needs rethinking]. / Envenimation cobraïque en France métropolitaine : repenser la prise en charge des envenimations exotiques.

We report a case of accidental green mamba (Dendroaspis viridis) envenomation in the suburbs of Paris. Although moderate, neurotoxic symptoms were clearly present. Immunotherapy with polyvalent serum FAV-Afrique was decided, but logistical problems prevented reasonably quick serum delivery to the hospital. Despite a spontaneously favourable outcome probably due to minimal envenomation, this case exemplifies a near-miss of the care system. Given the increasing incidence of potentially life-threatening exotic envenomations, management of similar cases should be improved. Besides breeders and health care professionals' information, we suggest that victims of an exotic envenomation be referred to a facility with experienced staff and ready access to a limited bank of carefully chosen antivenins.

[Paraspecific antivenins and exotic bites of snakes: about two case reports]. / Antivenins paraspécifiques et morsures de serpents exotiques : à propos de deux cas cliniques.

Envenomation from bite of exotic snakes is rare in France and represent a serious therapeutic problem: only an adapted antivenom is effective and obtaining such a treatment is a real difficulty. The authors report two clinical cases of envenomation with defibrination after bite by pit vipers from South America. The two patients were treated with nonspecific antivenom therapy with divergent results. The use of the paraspecific effects of antivenom can allow an effective treatment in the absence of specific antivenom, but requires to be known better.

[How the drug allergy risk in the intensive care software is considered? About a comparative study]. / Comment est pris en compte le risque allergique dans les logiciels spécifiques à la réanimation ? A propos d'une étude comparative.

The aim of this study was to evaluate the way the drug allergy risk was considered in five intensive care software available for the French market. It is an observational study conducted by a survey with the five firms asked during the 26th International Symposium on Intensive Care and Emergency Medicine in Brussels (March 2006). The drug allergic risk is documented to various degrees among the software selections. However, no software proposes an alternative or blocking of the prescription in case of allergy to a drug.

Cardiac troponin I release after hip surgery correlates with poor long-term cardiac outcome.

BACKGROUND AND OBJECTIVE: The aim of this study was to assess the incidence of perioperative myocardial damage detected by serial measurements of troponin I after hip surgery and its association with late cardiovascular outcome. METHODS: Troponin I was measured during the first three postoperative days in 88 consecutive patients undergoing hip surgery. Values above the 99th percentile (0.08 ng mL(-1)) were considered positive. Major cardiac events (cardiac death, myocardial infarction and cardiac failure) were recorded during hospital stay and 1 yr after surgery. RESULTS: Eleven patients (12.5%) exhibited elevated troponin I levels during hospital stay. Nine of them remained asymptomatic. During follow-up, 45% of them (5/11) suffered from a major cardiac event vs. 4% (3/76) for patients with normal postoperative troponin I levels (P = 0.0006). All-cause mortality rate was 36% (4/11) at 1 yr vs. 7% (5/71, P = 0.0131). Using multivariate Cox regression analysis adjusted for baseline data, independent factors associated with the occurrence of a cardiac event were troponin I elevation (OR=17.4-CI 95% 3.7-82) and age (OR=1.1 yr(-1)-CI 95% 1.01-1.21). Independent factors for all-cause mortality were troponin I elevation (OR=41.4-CI 95% 5.4-320.4), and age (OR=1.3 yr(-1)-CI 95% 1.1-1.4). CONCLUSION: Troponin I release is common after hip surgery and is associated with a 10-fold increased incidence of long-term major cardiac events as compared to patients with normal troponin I levels (45% vs. 4%).

[Use of rFVIIa (Novoseven) in the case of a patient with mitral valvular prothesis and anticoagulant accident]. / Utilisation du rFVIIA (Novoseven) lors d'un accident des anticoagulants chez une patiente porteuse d'une prothèse valvulaire mitrale.

We report the case of an haemorrhagic shock observed in a woman who received heparin for a cardiac valve in mitral position, efficiently treated with rFVIIa. The haemorrhagic complications under anticoagulation treatment remain rare, but can lead to real therapeutic dilemma. The use of rFVIIa has been evaluated in different clinical situations, including traumatic or post-operative haemorrhagic shock. The use of rFVIIa in the treatment of haemorrhagic complication under anticoagulation treatment is discussed.

[Treatment of a septic shock due to multiresistant Acinetobacter baumannii with tigecycline in combination]. / Traitement d'un choc septique à Acinetobacter baumannii multirésistant par tigécycline en association.

We report a case of pulmonary and bloodstream infection due to multiresistant Acinetobacter baumannii six days after a severe trauma. Clinical condition transiently improved following antimicrobial treatment with ticarcillin-clavulanate and rifampicin. However, a septic shock developed on the fourth day due to the emergence of a strain only sensible to cotrimoxazole, colistin and tigecycline. Cure was achieved after a two week treatment with piperacillin-tazobactam, cotrimoxazole and tigecycline. This case shows that combined antimicrobial therapy including tigecycline can be relevant in some severe pulmonary infections due to multiresistant A. baumannii.