Moderate temperature deposition of RF magnetron sputtered SnO2-based electron transporting layer for triple cation perovskite solar cells

The perovskite solar cells (PSCs) are still facing the two main challenges of stability and scalability to meet the requirements for their potential commercialization. Therefore, developing a uniform, efficient, high quality and cost-effective electron transport layer (ETL) thin film to achieve a stable PSC is one of the key factors to address these main issues. Magnetron sputtering deposition has been widely used for its high quality thin film deposition as well as its ability to deposit films uniformly on large area at the industrial scale. In this work, we report on the composition, structural, chemical state, and electronic properties of moderate temperature radio frequency (RF) sputtered SnO₂. Ar and O₂ are employed as plasma-sputtering and reactive gases, respectively. We demonstrate the possibility to grow a high quality and stable SnO₂ thin films with high transport properties by reactive RF magnetron sputtering. Our findings show that PSC devices based on the sputtered SnO₂ ETL have reached a power conversion efficiency up to 17.10% and an average operational lifetime over 200 h. These uniform sputtered SnO₂ thin films with improved characteristics are promising for large photovoltaic modules and advanced optoelectronic devices.

Study of wide bandgap SnOx thin films grown by a reactive magnetron sputtering via a two-step method

In the present work, we report on the microstructural and optoelectronic properties of SnO_x thin films deposited by a reactive radio frequency magnetron sputtering. After SnO_x growth by sputtering under O₂/Ar flow, we have used three different treatment methods, namely (1) as deposited films under O₂/Ar, (2) vacuum annealed films ex-situ, and (3) air annealed films ex-situ. Effects of the O₂/Ar ratios and the growth temperature were investigated for each treatment method. We have thoroughly investigated the structural, optical, electrical and morphology of the different films by several advanced techniques. The best compromise between electrical conductivity and optical transmission for the use of these SnO_x films as an n-type TCO was the conditions O₂/Ar = 1.5% during the growth process, at 250 °C, followed by a vacuum post thermal annealing performed at 5 × 10^–4 Torr. Our results pointed out clear correlations between the growth conditions, the microstructural and optoelectronic properties, where highly electrically conductive films were found to be associated to larger grains size microstructure. Effects of O₂/Ar flow and the thermal annealing process were also analysed and discussed thoroughly.

[Traumatic dissection of the left renal pedicle in a young adult]

Blunt trauma rarely causes renal pedicle dissection. Clinical signs are minimal and inconsistently reported. The diagnosis is based on computed tomographic angiography; arteriography is still useful when revascularization is considered. We report here a case of traumatic dissection with thrombosis of a juxta-aortic renal pedicle monitored in the intensive care unit. An endovascular procedure could not be proposed because of the juxta-aortic localization.

Insight into photon conversion of Nd3+ doped low temperature grown p and n type tin oxide thin films

p and n type SnO_x thin films are successfully functionalized with optically active Nd³⁺ ions for efficient UV photon conversion.

[Contribution of closed mitral commissurotomy in the surgery of rheumatic mitral stenosis]

The objective of this work was to study the indications, techniques and results of closed heart mitral commissurotomy in patients with rheumatic mitral stenosis in Morocco.

METHODS

All patients who had undergone closed heart mitral commissurotomy for rheumatic mitral stenosis, operated between 1999 and 2008 were collected in this study. Mitral stenosis was diagnosed and evaluated using Doppler echocardiography. Patients with commissural calcification, severe mitral regurgitation, and surgical tricuspid or aortic valvular disease were excluded from this study.

RESULTS

Six hundred and twenty-five patients have been collected. 62.2% were young with an age between 18 and 35 years and 491 (78.8%) were female. Seventy-nine percent of patients had stage III or IV NYHA and were in sinus regular rhythm. The closed heart mitral commissurotomy was performed for all patients through a left thoracotomy using either digital or dual dilatation. The mitral area was significantly increased postoperatively to 2.11 ± 0.32 with 100% opening of the anterior commissure, while the posterior commissure was opened only for 93.7% of patients. There were nine perioperative deaths (4.9%) and all patients who died had severe mitral stenosis (<0.8 cm(2)) with an elevated systolic pulmonary artery pressure (>60 mmHg).

CONCLUSION

The closed heart mitral commissurotomy provides excellent results in young patients with rheumatic mitral stenosis.

[Syphilitic aortic regurgitation: a sexually transmissible cardiopathy]

Syphilitic cardiovascular complications are currently rare. It concerns the tertiary phase of the disease and results in sacciform aneurysm of the thoracic aorta or ostial coronary artery stenosis. Syphilitic aortic regurgitation is even more rare. We illustrate it by a clinical observation and discuss its diagnosis and its treatment.

Properties of silicon nanoparticles embedded in SiNx deposited by microwave-PECVD

In this work, silicon-rich silicon nitride (SRN) layers were deposited on a silicon wafer by microwave-assisted plasma-enhanced chemical vapor deposition (MW-PECVD) using NH(3) and SiH(4) as precursor gases. The Si excess in the as-deposited layers as determined by the Rutherford backscattering technique was controlled by varying the precursor gas ratio. We were able to produce silicon nanoparticles (Si-nps) in the silicon nitride (SiN(x)) layers upon thermal annealing at high temperature. Energy-filtered TEM (EFTEM), complemented by photoluminescence measurements, were used to identify the experimental parameters in order to reach a high density of well-separated Si-nps (3 nm). Our results show that the MW-PECVD method is a suitable deposition tool for the formation of Si-nps in thin SRN layers.

The structural and optical properties of SiO2/Si rich SiNx multilayers containing Si-ncs

This work reports on the structural and optical properties of multilayers composed of silicon dioxide (SiO2) and silicon rich silicon nitride (SRN) films. These nanometer scale layers have been alternately deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) on quartz and silicon (Si) substrates. The samples have then been annealed at high temperature in order to obtain a crystallization of the Si atoms present in excess in the SRN films. The formation of crystalline Si has been witnessed by high resolution transmission electron microscopy (HREM) and micro-Raman measurements. Estimation of the Si-nanocrystal (Si-nc) sizes was possible by correlating the Raman's confinement model, the photoluminescence measurements and HREM imaging. The results clearly show that the band-gap of the Si-ncs formed can be controlled by this multilayer approach.

Right atrial rupture following a hoof kick to the chest wall

We report a case of right atrial rupture due to blunt trauma by a hoof kick to the anterior chest wall. We describe our successful management of this case. We suggest that a diagnosis of cardiac chamber rupture should be considered in all cases of blunt thoracic trauma.

[Ruptures of the posterior wall of the left ventricle after mitral valve replacement: surgical repair and prevention]

We report two cases of type III rupture of the left ventricle posterior wall, situated midway between the mitral annulus and the posterior papillary muscle and occurring in immediate continuations of a mitral valvular replacement. The first case has occurred at the moment of the canulas removal in a 28 years old patient operated for mitral stenosis. The tear was repaired with horizontal mattress sutures through felt strips on the external surface of the heart. The immediate post operative course was marked by bleeding recurrence and cardiac failure which has led to death. In the second case, a 68 years old man was operated for degenerative mitral insufficiency. The rupture has occurred just before closing the chest. The repair was realized successfully by using an intra-ventricular patch. The chordae tendinae removal constitutes a factor predisposing to the left ventricle posterior wall rupture. The repair has to use an intra-ventricular patch. The prevention is based on the preservation of the continuity between the mitral annulus and papillary muscles by preserving the sub-valvular apparatus or by using synthetic chordae.

[Quadriplegia secondary to potassium depletion]

Muscle paralysis due to potassium depletion are unusual. We report the case of a patient who developed quadriplegia and language disorders due to potassium depletion, following large intestinal resection. Potassium supplementation was given intravenously at a rate of 0.25 mmol.kg-1.h-1 during the first 48 h. This allowed complete total and rapid recovery from the paralysis.

[Emphysematous pyelonephritis: a case report]

In this study, a case of emphysematous pyelonephritis has been reported in a 70-year old diabetic male with a non-functional contralateral kidney. In spite of appropriate medical treatment and surgical drainage, the outcome was negative. The case in question concerned a rare form of the disease, i.e., emphysematous pyelonephritis, a severe and necrotizing infection which is characterized by the presence of intraparenchymal gas produced by anaerobic bacteria, and the rapid development of acute sepsis or septic shock. Medical treatment alone is seldom sufficient, and surgical intervention, in most instances consisting of radical nephrectomy rather than surgical drainage, is advocated due to the extent of the necrotic lesions.

[Pheochromocytoma. Severe and uncommon presentations]

We report five cases of phaeochromocytoma in patients admitted for myocardial infarction, severe cardiac failure, with shock, stroke and ischaemic gangrene of a lower limb respectively. The pathophysiology of these events is discussed. Early surgery prevents visceral damage from massive release of catecholamines.

[Cerebral infarction, pseudolupic syndrome and myxoma of the left atrium]

Left atrial myxomas are a rare stroke etiology (0.4%). They frequently present general symptoms such as fever, weight loss and an inflammatory syndrome, but the pseudolupic syndrome with cutaneous features and vasomotor symptoms is rarely described. We report the case of a 38-year old man who presented in March 1995 a stroke caused by a left atrial myxoma. There was also pseudolupic clinical and biological manifestations which disappeared after ablation of the myxoma. Cerebral angiography showed a small carotid aspect which evoked carotid dissection or carotid siphon occlusion. The authors discuss neurologic and pseudolupic manifestations of left atrial myxomas, and their physiopathologic mechanism.

[Multiple myxoma of the right ventricle with infiltration of the pulmonary infundibulum and arteries]

The authors report a case of multiple myxoma of the right ventricle treated surgically. One of the myxomas infiltrated the right ventricular ourflow tract, the main pulmonary artery and its branches. This case underlines the difficulty of radical resection of infiltrating cardiac myxomas.

[Double recurrence of myxoma of the left atrium. Apropos of a case]

Multiple recurrences of cardiac myxomas are rare and high-light the problem of re-operation. We report a case of double recurrence of left atrial myxoma and analyse the causes of recurrence. In our case, the first myxoma was inserted in the left inter-atrial septum, and the first recurrent tumor was inserted near the pulmonary vein, forming adhesion with the inter-atrial septum. The second recurrent tumor was inserted in the inter-atrial septum. The first operation resected the tumor, including part of the inter-atrial septum, and the sides of the septum were sutured. The two following operations used a patch for the septoplasty. This case is sporadic and not included in the high risk myxoma recurrence syndrome. Incomplete tumor resection is incriminated in one third of recurrences but seems unlikely in our case.

[Ulcero-hemorrhagic rectocolitis: operative morbidity and mortality. Apropos of 100 cases]

We performed a retrospective analysis of morbidity and mortality in 100 cases of ulcerative colitis treated at the surgical care unit of the Ibn Sina hospital over a 10 year period from 1984 to 1994. One major complication, usually infection, was observed in 40% of the cases. Overall mortality was 22%, a rate higher than the larger published series. The main factor incriminated in our study ; besides surgical circumstances, was the delay in care, including in the intensive care unit. It must be concluded that medical and surgical management must be initiated as soon as a flare up is diagnosed.

[Hydatid cysts of the liver. Therapeutic and prognostic classification. 378 cases]

OBJECTIVES

We retrospectively examined our clinical data on hydatic cysts of the liver collected over the last 10 years in order to determine a classification which could be used to guide future therapeutic decisions.

METHODS

From 1982 to 1992, hydatic cysts of the liver were surgically removed in 378 patients (mean age 38 +/- 12 years). Echography had been performed in all patients. Other preoperative investigations included computerized tomodensitometry (n = 57) and arteriography of the caeliomesenteric arteries (n = 12). Histological examination of surgical specimens included research for parasite inclusions within the pericyst and the hepatic parenchyma.

RESULTS

Single cysts were found in 65.7% of the cases, double cysts in 20% and multiple cysts in 12.5%. Histology revealed parasites in the pericyst in 129 cases (34%) and a fistula from the cyst to the bile duct was observed in 47 cases (12.5%). A classification was obtained based on 5 criteria: localization and number of cysts, cyst content, morphology of the pericyst and biliary-cyst fistula.

CONCLUSION

The excellent correlation between this classification and prognosis provides a valuable tool for the management of hepatic hydatic cysts.

Low Teperature Synthesis of Silicon Oxide and Oxynitride Films by Reactive Laser Ablation

Silicon oxide and oxynitride films are deposited, at low temperature (≤ 450°C) by pulsed ArF excimer laser ablation from silicon, silicon monoxide, fused silica and silicon nitride targets, performed under vacuum and in oxygen atmosphere. We investigate in this paper the specific influence of laser fluence, target materials, substrate temtperature and oxygen pressure on the composition and final properties of SiOxNy grown layers. The synthesis of good quality SiO2 films is demonstratedx. By contrast, the preparation of stoichiometric Si7N4 layers by laser ablation has to be optimized.

[Orthotopic transplantation of segmental hepatic graft from living donors in the dog. Technic and results]

The authors describe new technic of non-auxiliary orthotopic transplantation of segmental liver harvested from living dogs. 32 dogs were utilized. In the donor dogs, the left medial and lateral lobes were mibilized. The left portal branch, left hepatic artery, left biliary branch and the left hepatic vein were dissected free. The segmental liver graft was perfused and cooled in-situ through the left portal vein. The recipient dogs underwent two steps total hepatectomy: First the segments I, II, III, IV and V were resected. The segments VI and VII were maintained as well as the right portal vein and the retro-hepatic inferior vena cava order to keep the splanchnic and caval flux and to avoid the spleno-cavo-jugular by-pass. The segmental liver graft was then transplanted in an orthotopic position. Termino-lateral hepatico-caval anastomosis and left porto-portal anastomosis as well as arterial and biliary reconstruction were executed. All the donors survived more than 30 days. Nine recipient dogs died during the first three post-operative days from hemorrhage (3 dogs), fibrinolysis (2 dogs), primary non function of the graft (2 dogs) and hepatic artery thrombosis (1 dog). Seven recipients survived more than 30 days.