Carbon nanotube-amorphous silicon hybrid solar cell with improved conversion efficiency.

We report a hybrid solar cell based on single walled carbon nanotubes (SWNTs) interfaced with amorphous silicon (a-Si). The high quality carbon nanotube network was dry transferred onto intrinsic a-Si forming Schottky junction for metallic SWNT bundles and heterojunctions for semiconducting SWNT bundles. The nanotube chemical doping and a-Si surface treatment minimized the hysteresis effect in current-voltage characteristics allowing an increase in the conversion efficiency to 1.5% under an air mass 1.5 solar spectrum simulator. We demonstrated that the thin SWNT film is able to replace a simultaneously p-doped a-Si layer and transparent conductive electrode in conventional amorphous silicon thin film photovoltaics.

Psychogenic seizures: long-term outcome in patients with and without epilepsy.

OBJECTIVES: Psychogenic non-epileptic seizures (PNES) may resemble epileptic events. Epileptic and non-epileptic seizures are not mutually exclusive phenomena and may coexist in the same patient. The aim of this study was to evaluate the long-term outcome of psychogenic events in patients with PNES alone and those with both PNES and epilepsy (PNES + EPI) as diagnosed by video-EEG (vEEG) monitoring. MATERIALS AND METHODS: All adult admissions to the Tel-Aviv Medical Center's vEEG unit between 2004 and 2009 were screened for the presence of PNES. We retrospectively retrieved data from their medical files and supplemented the follow-up by a telephonic questionnaire. RESULTS: Eligible patients (n = 51) were divided into those with PNES + EPI (n = 24) and those with PNES alone (n = 27). The follow-up period was 4.8 ± 0.3 and 4.3 ± 0.3 years, respectively. Both groups had similar female predominance and similar age at admission to the vEEG unit. Time from PNES onset to hospitalization was longer in PNES patients compared to those with PNES + EPI. The majority of subjects in each group reported a history of at least one major stressful life event. Opisthotonus was significantly more frequently observed in PNES patients, and they had more events during vEEG hospitalization. Psychogenic events ceased during the follow-up period in 22% of the PNES patients and in 58% of the PNES + EPI patients (P > 0.001). CONCLUSION: Our results indicate that following vEEG-based diagnosis of PNES, the long-term outcome of PNES cessation may be more favorable for patients with concomitant epilepsy than for patients without epilepsy.

[Inter-hospital transfer for severe postpartum hemorrhage]. / Modalités d'un transfert inter-hospitalier dans le cadre d'une hémorragie sévère du post-partum.

OBJECTIVES: To elaborate guidelines for inter-hospital transfer for severe postpartum hemorrhage. MATERIALS AND METHODS: Bibliographic search in Medline and Cochrane Database by PubMed. RESULTS: Severe postpartum hemorrhage sometimes needs inter-hospital transfer for arterial embolization or admission in intensive care unit. Validation of this transfer needs multidisciplinary decision, including obstetricians, anesthesiologist-intensivists of primary and tertiary center and prehospital medical team. If bleeding is too important or in case of uncontrolled hemorrhagic shock, inter-hospital transfer may be dangerous and local surgical hemostasis should be preferred. In such situation, prehospital medical team should stay on scene for help especially in small institutions where medical and paramedical resources are sometimes insufficient. In case of inter-hospital transportation, organ failure should be controlled and blood transfusion, if needed, should be initiated before. The patient should be transferred to a multidisciplinary center (surgery, anesthesiology and ICU, interventional radiologist, blood bank). CONCLUSION: Inter-hospital transfer for severe postpartum hemorrhage is possible under certain conditions including continuation of blood transfusion and organ failure correction.

Prehospital use of minimally invasive direct cardiac massage (MID-CM): a pilot study.

BACKGROUND: Internal cardiac compressions are more efficient than closed chest compressions (CCC) in cardiac arrest (CA). AIM OF THE STUDY: To evaluate the prehospital feasibility of performing a new method of minimally invasive direct cardiac massage (MID-CM TheraCardia Inc.). METHODS: Prospective non-randomized open study, after ethical committee approval. Inclusion of 18-85 years old patients in witnessed CA if BLS>5 min and unsuccessful ACLS>20 min after CA. The MID-CM is an atraumatic manual cardiac pumping system deployed in the thoracic cavity through a small incision. Evaluation of: ease of insertion and performing MID-CM, complications, end-tidal CO(2) (PETCO(2)), non invasive arterial blood pressure (NIBP) and return of spontaneous circulation (ROSC). Values are mean+/-SD (min-max). RESULTS: Twenty-five patients included. Mean age 59+/-16 years (26-85); BLS started at 8+/-5 min (0-20), compressions started at 47+/-10 min (29-74) after CA. Dissection and insertion was fast and easy (<1 min). Deployment of the MID-CM was difficult in two patients because of pericardium adhesions and cardiomegaly. In six patients compressions were more difficult because of a 'stone heart' phenomenon. Compressions were possible during ambulance transport of four patients. There was a good palpable carotid pulse in all patients receiving internal compressions. There was a trend in increase of PETCO(2) compared to CCC. NIBP could be measured during MID-CM compressions in 9 patients (systolic>85 mmHg), never during CCC. Seven patients had a ROSC, but only four patients were admitted alive. There was no long term survival. One patient had a serious complication (heart rupture). DISCUSSION: Prehospital use of MID-CM is possible, but it is not comparable to any other resuscitation technique. Training of medical teams is mandatory to obtain good skills and to avoid complications. Further studies are necessary to evaluate efficiency and survival compared to closed chest compressions.

[Cardiac arrest outside the hospital]. / Arrêt cardiaque extra-hospitalier.

Out-of-hospital cardiac arrest remains a clinical problem with a survival rate of less than 5%. Prompt initiation of cardiopulmonary resuscitation and rapid delivery of advanced cardiac-life procedures are required. Combined in-hospital management by experienced cardiologists and intensive care specialists is recommended. Acute coronary-artery occlusion is frequent and poorly predicted by clinical and electrocardiographic findings. Accurate diagnosis by immediate coronary angiography can be followed if necessary by coronary angioplasty. Survivors undergo extensive work-up to determine the indications of an implantable defibrillator or coronary revascularization.

[Is the direct admission to the recovery service or to the intensive care unit of patients cared for by the Smur system justified?]. / L'admission directe en service de réanimation ou de soins intensifs des patients pris en charge par le Smur est-elle justifiée?

STUDY DESIGN: The French system of Samu-Smur allows the admission of patients directly in intensive care unit (ICU). The aim of this study is to examine the utility of the Samu-Smur with regard to such direct admission (DA). PATIENTS AND METHODS: This retrospective study was performed by the Samu of Paris. Patient details were gathered from three reports: namely hospitalization, transport and regulation reports. These were analysed to decide whether the admission diagnostic was exact, whether the patient's condition was serious, whether the prehospital treatment justified direct admission into an ICU and whether the management was coherent. RESULTS: In 1997, 409 (31%) cases were studied among the 1,350 admitted patients in ICU. Three groups of patients were classified according to admission to surgical (n = 54), medical (n = 180), cardiological ICU (n = 175). The prehospital diagnosis was confirmed by the hospitalization report in 91% of patients in the all three groups. The patient's condition was found to the serious in all cases. Justification of the treatment was respectively found in 96, 88 and 84% of patients. The coherence of management was confirmed in 94, 96 and 89%. DISCUSSION: This study has shown that Samu-Smur management lead to justified DA in ICU for all patients in the study. Prospective studies are needed to show the advantages of this strategy in term of speed of management and outcome.

Recent innovations in total liquid ventilation system and component design.

In addition to partial liquid ventilation (PLV), total liquid ventilation (TLV) is being explored as a potential therapy to mitigate ventilator-associated lung injury and acute lung failure. TLV is ventilation of the completely liquid-filled lung using tidal flow of oxygenated perfluorochemical (PFC) liquid delivered by a "liquid ventilator." Most TLV research to date has focused on "small" lung (animals < 20 kg; vast majority < 5 kg), with primary relevance to its use in children. Recent investigations regarding TLV in larger lungs have helped define new design challenges for liquid ventilator systems to succeed as clinical products. Adult TLV requires the delivery of significantly higher liquid tidal volumes, with proportionately greater O2 and CO2 exchange. Although a simple scale-up of liquid ventilator components such as pumps, tubing, fittings, and gas and heat exchangers might be considered the most straightforward way to compensate for the increased demand, there are a number of practical problems with this approach. These include requirements to: 1) minimize priming volume, 2) minimize PFC evaporative loss, 3) suppress flow-induced cavitation in fittings and components, 4) monitor and control ventilation based on pressure signals exhibiting noise, 5) maintain ability and accuracy of delivered breaths in a fluid mechanical environment having higher inertial forces and pressure losses than for small lung systems, 6) use disposable or sterilizable fluid-contacting components, and 7) maintain PFC materials compatibility. TLV system and component innovations implemented on a new large-animal liquid ventilator prototype are presented. The advantages of new pumps, gas exchangers, and temperature-control components are discussed.

[Pre-hospitalization reanimation in cardiac arrest]. / La réanimation préhospitalière des arrêts cardiaques.

THE SURVIVAL CHAIN: The delay to restoration of spontaneous circulation is the key to prognosis of cardiac arrest occurring outside the hospital. Among the many etiologies of cardiac arrest, sudden onset ventricular fibrillation is the number one cause of sudden death in adults. Better prognosis depends on effective organisation founded on the concept of a "survival chain". ALERT AND RESUSCITATION: By alerting the emergency units and performing the basic gestures of cardiopulmonary resuscitation (freeing the airways, mouth-to-mouth ventilation and closed chest cardiac massage) those witnessing the event take the first steps in the survival chain while waiting for the paramedical and medical teams to arrive. DEFIBRILLATION: In case of ventricular fibrillation, prognosis is directly related to the delay to defibrillation. Defibrillators used by specially trained paramedics before a physician arrives on the scene have considerably improved prognosis. SPECIALIZED RESUSCITATION: Precise algorithms help guide treatment in accordance with the observed cardiac rhythm. Tracheal intubation and artificial ventilation are fundamental. Among the useful drugs, epinephrine is by far the most important for improving myocardial and cerebral perfusion, improving the chances of recovering spontaneous circulation. The only anti-arrhythmic drug currently used is lidocaine. Infusion of alkaline fluid is only useful in specific cases of prolonged resuscitation. Expired CO2 monitoring may be a useful guide, but discontinuing resuscitation is strictly a medical decision. AFTER RESUSCITATION: When spontaneous circulation has been achieved, the patient must be transported to a cardiac hospital for specialized care and etiological treatment.

The autowave modes of solid phase polymerization of metal-containing monomers in two- and three-dimensional fiberglass-filled matrices.

The phenomenon of autowave (frontal) solid phase polymerization of metal-containing monomers based on metal-acrylamide complexes is considered. The comparison of the features of autowave processes realized in both the single-component matrices of the monomer and the matrices filled by the fiberglass materials is performed. The unstable regimes of the polymerization wave as well as the conditions for the stabilization of the flat front in the filled matrices are described. The peculiarities of the frontal regimes in the three- and two-dimensional media are studied. Some possibilities for using of autowave polymerization in the fabrication of the polymer-fiberglass composites and composition prepregs are discussed. (c) 1999 American Institute of Physics.

End-tidal carbon dioxide during out-of-hospital cardiac arrest resuscitation: comparison of active compression-decompression and standard CPR.

STUDY OBJECTIVES: To compare the maximal end-tidal carbon dioxide pressure (ETCO2 peak) values obtained during standard (S-CPR) and active compression-decompression CPR (ACD-CPR) during prolonged resuscitation in out-of-hospital cardiac arrest. DESIGN: Prospective, randomized crossover study. SETTING: City with a population of 3.5 million, served by an emergency medical service system providing advanced cardiac life support. PARTICIPANTS: Patients with nontraumatic out-of-hospital cardiac arrest. INTERVENTIONS: Patients were randomly assigned to receive first, for a period of 3 minutes, either ACD-CPR or S-CPR; then the two methods were alternated. ETCO2 was continuously monitored and computed. MEASUREMENTS AND RESULTS: Sixteen patients (48 +/- 20 years old) were included; in 12, return of spontaneous circulation was achieved, and 5 were admitted alive to the hospital. A statistically significant increase in ETCO2 peak was obtained with ACD-CPR (27.6 +/- 3 mm Hg) compared with S-CPR (15.6 +/- 2.2 mm Hg). No major adverse effect possibly related to ACD-CPR was observed. CONCLUSION: This prospective study suggests that ACD-CPR may improve cardiac output compared with S-CPR.

The effect of heated wire circuits on humidification of inspired gases.

We performed this study to determine the effect of heated wire circuits on humidity delivered by several humidifiers commonly used during anesthesia. Humidifier bases from three manufacturers with several humidifying chambers for each base were tested using both heated and unheated circuits. Delivered humidity and circuit temperature were measured at the distal end of the circuit. Each chamber was tested under both continuous flow (CF) and intermittent flow (IF) conditions. IF was provided by a Servo 900 B ventilator. Adjustments of flow and volume were made for pediatric chambers. At 90 L/m CF, humidifier performance was unsatisfactory with both heated and unheated circuits. At 15 and 45 L/m CF, both distal circuit temperature (DCT) and humidity were within acceptable limits; unheated circuits delivered more humidity than heated circuits (P < 0.05). Relative humidity was lower at 45 L/m CF than at 15 L/m (P < 0.05). During IF while all chambers provided satisfactory humidity, humidity was greater when unheated circuits were used. We conclude that when heated circuits are used, humidifying systems may fail to deliver 100% humidity to patients.

[Cardio-respiratory arrest. New concepts and physiopathological consequences]. / Arrêt cardio-respiratoire. Conceptions nouvelles et conséquences physiopathologiques.

In the past few years, many studies have been devoted to cardiac arrest (CA) resuscitation. The "Chain of Survival" concept is considered as the best comprehensive approach of CA prognostic improvement. It includes 4 links: early access (recognition of early signs of CA and activation of the emergency medical system), early cardiopulmonary resuscitation, early defibrillation of ventricular fibrillations and early advanced cardiac life support (intubation, intravenous medication). Non withstanding all the recent progress en physiology or therapeutics, the early management is still the basis of the prognosis. That is why prehospital care organization is the main determinant of CA survival.

Modular indirect calorimeter suitable for long-term measurements in multipatient intensive care units.

OBJECTIVE: The construction of an indirect calorimeter capable of long-term automated sequential monitoring of multiple patients in adult and pediatric ICUs. DESIGN: A prototype system utilizing modular engineering principles, including central respiratory mass spectrometer; validation by organic solvent combustion and nitrogen dilution methods, and Tissot spirometer. SETTING: Surgical and pediatric ICUs in a tertiary care university hospital. RESULTS: When expired minute volume was measured over a range of 4 to 28 L in six intubated patients, expired minute volume measured by the prototype system demonstrated a correlation coefficient of .998 compared with simultaneous expired minute volume measured by a Tissot spirometer. Organic solvent combustion demonstrated a maximum error of 3.8% for oxygen consumption (VO2) and an average error of 1.73 +/- 1.25% (SEM). The maximum error for the respiratory quotient was 3.0%, with an average error of 1.75 +/- 1.07%. VO2 (predicted) vs. VO2 (measured) demonstrated a correlation coefficient of .997. Validation with the nitrogen dilution method over a range of FIO2 from 0.21 to 0.60 demonstrated a maximum error of 7.9%, with an average error of -1.72 +/- 1.1% (n = 51). CONCLUSIONS: Indirect calorimetry by means of a shared system for measurements in multiple patients in ICUs is feasible and cost effective utilizing modular principles and a centralized respiratory gas analyzer.

[Diagnosis and treatment of neoplastic and cystic formations of the mediastinum]. / Diagnostika i lechenie opukholevykh i kistoznykh obrazovanii sredosteniia.

The article analyses problems of the diagnosis and surgical and complex treatment of 56 patients with neoplastic and cystic structures in the mediastinum. In the group of 56 patients 28 had neoplastic diseases of the mediastinum, in 11 of them the tumors were malignant. According to the data presented, postoperative mortality in mediastinal cysts was zero. In mediastinal tumors the preoperative diagnosis was authentically established in 11 of 28 patients (39.3%), postoperative mortality was 7%. An original method for hemostasis in bleeding from the seat of the mediastinal tumor is described. The survival of patients with malignant mediastinal structures treated by partial resection of the tumor, radiotherapy and polychemotherapy varies from 6 months to 4 years, which allows the conclusion that wider application of complex treatment is expedient.