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

This work reports on a detailed study of the thermoelectric properties of the double-substituted tetrahedrites Cu_12−xCo_xSb_4−yTe_yS₁₃ in a wide range of temperatures (5–700 K) with a peak ZT of 0.8 at 700 K.

Electronic structure, low-temperature transport and thermodynamic properties of polymorphic β-As2Te3

The first-order lattice distortion undergone by β-As₂Te₃ around 200 K results in a cycling effect on its transport properties.

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.

[Antibodies against high frequency antigen and total knee replacement]

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.

[Understanding mistake-proofing]

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".

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).

[Use of rFVIIa (Novoseven) in the case of a patient with mitral valvular prothesis and anticoagulant accident]

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.

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%).

Spin fluctuations and superconductivity in Mo3Sb7

Temperature dependences of the magnetic susceptibility, specific heat, and electrical resistivity have been measured for the Mo(3)Sb(7) compound in the 0.6-350 K range. This compound exhibits bulk superconductivity occurring at 2.25 K and follows the Kadowaki-Woods relation, A/gamma(2)=1.0 x 10(-5) microOmega x cm(K x mol/mJ)(2), as a heavy-fermion system does. We show, from experimental evidence and theoretical argument, that Mo(3)Sb(7) can be classified as a coexistent superconductor-spin fluctuation system. The McMillan equation including paramagnon effects was found to give an accurate estimation of the transition temperature.

Les complications cardiovasculaires aiguës de la cocaïne. À propos de deux observations

Concerning any socioprofessional category, some addictive drugs like cocaine are responsible for many complications. The authors relate two case reports of young patients who suffered from cardiovascular accidents due to this drug. The first one was diagnosed with an ischemic stroke caused by carotid artery dissection and a leg distal vascular obliteration, the second one with a myocardial infarction with transient left ventricular dysfunction. Through these two case reports, the authors take stock of the pathophysiological and therapeutic knowledge of cardiovascular accidents after cocaine intake.

[Anaesthesia and amiodarone-associated hyperthyroidism]

Amiodarone can induce severe hyperthyroidism that justifies its withdrawal and initiation of antithyroid drugs. Impossibility to stop amiodarone, failure to control hyperthyroidism and unfavourable evolution can lead to thyroidectomy. Cardiac manifestations, persistence of hyperthyroidism and interactions between amiodarone and anaesthetic or haemodynamic drugs may contraindicate anaesthesia. We report nine consecutive cases of amiodarone-associated hyperthyroidism that prompted us to perform thyroidectomy under general anaesthesia. The features and anaesthetic data of patients were noted. The antithyroid medical treatment failed in all patients. After thyroidectomy, evolution was favourable in all nine cases, without any intra or postoperative complication, in spite of the extent of hyperthyroidism and the severity of the associated cardiac problems. Despite potential high risks, thyroidectomy for amiodarone-induced hyperthyroidism does not seem to increase morbidity or mortality and allows a quick return to euthyroidism and reintroduction of amiodarone.

L’embolie pulmonaire au secours de la tamponnade cardiaque

The association of cardiac tamponade and pulmonary embolism has not previously been described. We report the case of a patient, who presented with such an association, due to an underlying pulmonary carcinoma. When a major pericardial effusion is associated with pulmonary hypertension, some echocardiographic signs of tamponade may appear, such as a moderate right ventricular collapse, or the absence of a paradoxical septum. The presence of pulmonary hypertension in this context of tamponade may have paradoxically saved the life of this patient.

Allogenic bone marrow transplantation with a donor presenting with an acute hepatitis A

We report the unique occurrence of an allogenic bone marrow transplantation performed as the donor was suffering from an acute hepatitis A. The bone marrow was contaminated at the time of collection, as demonstrated by hepatitis A virus (HAV) RNA detected by RT-PCR. Hepatitis A virus infection in such a situation could have resulted in a severe liver disease in the recipient. However, although we could demonstrate that the recipient had been infected, he did not develop a symptomatic hepatitis A but only minor disturbances of liver function tests between days 35 and 55. Both the postponement of the transplantation and the use of intravenous polyvalent immunoglobulins have probably played a key role in decreasing the viral load and allowing a rapid clearance of the virus. A possible role of the grafted immune system might also be envisaged, as suggested by the de novo synthesis of IgM in the recipient.

[A cause of intubation failure: a subglottic bridge]

We report the case of a patient with a history of facio-thoracic burns, the treatment of which included prolonged intubation, whose trachea could not be intubated because of a subglottic obstacle. The ventilation was easily controlled with a laryngeal mask. At the end of surgery for postburn cheloids, laryngoscopy through the laryngeal mask showed a transversal subglottic laryngeal band, a probable sequela of the previous prolonged intubation. The band was resected one week later. The conventional indicators for difficult intubation cannot detect the laryngotracheal obstacles to tracheal tube insertion.

Development of enzyme-linked immunoassays for human angiotensin I converting enzyme suitable for large-scale studies

OBJECTIVE

To develop and validate a simple immunological assay for human angiotensin converting enzyme (ACE) based on monoclonal antibodies.

METHODS

Microtitre plates were coated with mouse monoclonal antibody (MoAb) to human ACE (9B9) and incubated with diluted samples of human plasma. In the sandwich enzyme-linked immunosorbent assay (ELISA), the plasma ACE, bound to MoAb 9B9, was revealed using polyclonal anti-ACE antibodies and alkaline phosphatase conjugated to goat anti-rabbit immunoglobulin G. In the plate precipitation assay the ACE activity, quantitatively precipitated from human plasma by MoAb 9B9, was measured by enzymatic fluorimetric assay with p-benzyloxycarboxyl-glycyl-L-histidyl-L-leucine or p-benzyloxycarboxyl-L-phenylalanyl-L-histidyl-L-leucine as substrate, directly in the wells.

RESULTS

These assays are specific for the amino-terminal domain of ACE and recognize differences in the conformations of native and recombinant ACE. The sensitivity of the sandwich ELISA was 200 pg/ml assay medium; it quantifies the ACE in 10 microliters human plasma or less. Intra- and inter-assay variability coefficients were 6.2 and 13.6%, respectively. Both variants of the assay determined the plasma ACE concentration in the presence of ACE inhibitors or EDTA. The ACE concentrations were determined by sandwich ELISA in a population of 138 middle-aged healthy Caucasian subjects. They were strongly correlated with the ACE gene insertion/deletion (I/D) polymorphism, which accounted for 20% of the variance of plasma ACE concentration in this population and 16-24% of the variance in plasma ACE activity as measured with three different enzymatic assays.

CONCLUSION

The ACE concentration (but not inhibition) can be determined by this ELISA which is suitable for large-scale studies of plasma ACE levels.

[Risks of hydrogen peroxide irrigation in military surgery]

Two cases of severe complications due to injection of hydrogen peroxide under pressure into areas of muscular attrition in war wounds are reported. In both cases the administration of hydrogen peroxide was associated with tachypnoea, with major arterial desaturation and a precordial "mill-wheel" murmur was heard. In one case, these symptoms were followed by hemiplegia caused by paradoxical arterial gas embolism, and in the other case by a pulmonary oedema confirmed by computerized tomography. Both patients recovered under hyperbaric oxygen therapy. The release of gaseous oxygen under the effect of tissue catalase and the membrane peroxydasic activity of hydrogen peroxide initiate such complications. The injection of hydrogen peroxide under pressure into a closed or partially closed cavity should therefore be strictly prohibited.

[Cesarean section, mitral valve disease and pulmonary hypertension. Implications of hemodynamic monitoring on anesthetic management]

We present the case of a 25-year-old woman with mitral valve disease and severe pulmonary hypertension scheduled for Caesarean section under general anaesthesia. General anaesthesia for such cardiac patients requires usually high doses of fentanyl prior to intubation, which favours maternal inhalation and neonatal ventilatory depression. Invasive haemodynamic monitoring allowed a rapid sequence induction, with an optimal drug titration and an early recovery.

Self-poisoning with the beta-blocker bisoprolol

A case of bisoprolol self-poisoning resulting in full recovery of the patient is described. The peak plasma level of bisoprolol was 541 ng ml-1. Sinus bradycardia was the only symptom observed, suggesting that cardioselectivity and absence of membrane stabilizing activity contribute to reduce the severity of beta-blocker intoxication.