140 research outputs found
Dip coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project
The research program to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by dip-coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon is reported. The initial effort concentrated on the design and construction of the experimental dip-coating facility. The design was completed and its experimental features are discussed. Current status of the program is reported, including progress toward solar cell junction diffusion and miscellaneous ceramic substrate procurement
Dip coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project
To date, an experimental dip-coating facility was constructed. Using this facility, relatively thin (1 mm) mullite and alumina substrates were successfully dip-coated with 2.5 - 3.0 ohm-cm, p-type silicon with areas of approximately 20 sq cm. The thickness and grain size of these coatings are influenced by the temperature of the melt and the rate at which the substrate is pulled from the melt. One mullite substrate had dendrite-like crystallites of the order of 1 mm wide and 1 to 2 cm long. Their axes were aligned along the direction of pulling. A large variety of substrate materials were purchased or developed enabling the program to commence a substrate definition evaluation. Due to the insulating nature of the substrate, the bottom layer of the p-n junction may have to be made via the top surface. The feasibility of accomplishing this was demonstrated using single crystal wafers
Dip coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project
The technical and economic feasibility of producing solar cell quality sheet silicon by dip-coating one surface of carbonized ceramic substrates with a thin layer of large grain polycrystalline silicon was investigated. The dip-coating methods studied were directed toward a minimum cost process with the ultimate objective of producing solar cells with a conversion efficiency of 10% or greater. The technique shows excellent promise for low cost, labor-saving, scale-up potentialities and would provide an end product of sheet silicon with a rigid and strong supportive backing. An experimental dip-coating facility was designed and constructed, several substrates were successfully dip-coated with areas as large as 25 sq cm and thicknesses of 12 micron to 250 micron. There appears to be no serious limitation on the area of a substrate that could be coated. Of the various substrate materials dip-coated, mullite appears to best satisfy the requirement of the program. An inexpensive process was developed for producing mullite in the desired geometry
Automated implantable cardiac defibrillator and biventricular thoratec assist device as bridge to transplantation in a patient with sarcoidosis
AbstractJ Thorac Cardiovasc Surg 2001;121:1198-
Coliform pyosalpinx as a rare complication of appendicectomy: a case report and review of the literature on best practice
<p>Abstract</p> <p>Introduction</p> <p>Coliform pyosalpinx is a rare entity. We report a case that occurred three months after appendicectomy for gangrenous appendicitis. There follows a literature review on best practice for the treatment of pyosalpinx.</p> <p>Case presentation</p> <p>A seventeen year old girl presented with an acute abdomen three months after an appendicectomy for gangrenous appendicitis. Intraoperative findings were bilateral pyosalpinx treated by aspiration, saline and Betadine irrigation and intravenous antibiotics.</p> <p>Conclusion</p> <p>Microbiological analysis of the pus revealed <it>Escherichia coli </it>and anaerobes. Chlamydia and Candida were not isolated. This is the first known reported case of Coliform Pyosalpinx following appendicectomy. The best treatment does not necessarily involve salpingectomy especially in women of reproductive age where fertility may become compromised.</p
One year follow-up of the multi-centre European PARTNER transcatheter heart valve study
BackgroundTranscatheter aortic valve implantation (TAVI) has emerged as a new therapeutic option in high-risk patients with severe aortic stenosis.AimsPARTNER EU is the first study to evaluate prospectively the procedural and mid-term outcomes of transfemoral (TF) or transapical (TA) implantation of the Edwards SAPIEN® valve involving a multi-disciplinary approach.Methods and resultsPrimary safety endpoints were 30 days and 6 months mortality. Primary efficacy endpoints were haemodynamic and functional improvement at 12 months. One hundred and thirty patients (61 TF, 69 TA), aged 82.1 ± 5.5 years were included. TA patients had higher logistic EuroSCORE (33.8 vs. 25.7, P <0.0005) and more peripheral disease (49.3 vs. 16.4, P< 0.0001). Procedures were aborted in four TA (5.8) and six TF cases (9.8). Valve implantation was successful in the remaining patients in 95.4 and 96.4, respectively. Thirty days and 6 months survival were 81.2 and 58.0 (TA) and 91.8 and 90.2 (TF). In both groups, mean aortic gradient decreased from 46.9 ± 18.1 to 10.9 ± 5.4 mmHg 6 months post-TAVI. In total, 78.1 and 84.8 of patients experienced significant improvement in New York Heart Association (NYHA) class, whereas 73.9 and 72.7 had improved Kansas City Cardiomyopathy Questionnaire (KCCQ) scores in TA and TF cohorts, respectively.ConclusionThis first team-based multi-centre European TAVI registry shows promising results in high-risk patients treated by TF or TA delivery. Survival rates differ significantly between TF and TA groups and probably reflect the higher risk profile of the TA cohort. Optimal patient screening, approach selection, and device refinement may improve outcomes
Trajectory Estimation for Particles Observed in the Vicinity of (101955) Bennu
We analyze the trajectories of 313 particles seen in the near‐Bennu environment between December 2018 and September 2019. Of these, 65% follow sub‐orbital trajectories, 20% undergo more than one orbital revolution around the asteroid, and 15% directly escape on hyperbolic trajectories. The median lifetime of these particles is ~6 h. The trajectories are sensitive to Bennu's gravitational field, which allows us to reliably estimate the spherical harmonic coefficients through degree 8 and to resolve nonuniform mass distribution through degree 3. The particles are perturbed by solar radiation pressure, enabling effective area‐to‐mass ratios to be estimated. By assuming that particles are oblate ellipsoids of revolution, and incorporating photometric measurements, we find a median axis ratio of 0.27 and diameters for equivalent‐volume spheres ranging from 0.22‐‐6.1 cm, with median 0.74 cm. Our size distribution agrees well with that predicted for fragmentation due to diurnal thermal cycling. Detailed models of known accelerations do not produce a match to the observed trajectories, so we also estimate empirical accelerations. These accelerations appear to be related to mismodeling of radiation pressure, but we cannot rule out contributions from mass loss. Most ejections take place at local solar times in the afternoon and evening (12:00‐‐24:00), although they occur at any time of day. We independently identify ten ejection events, some of which have previously been reported. We document a case where a particle ricocheted off the surface, revealing a coefficient of restitution 0.57±0.01 and demonstrating that some apparent ejections are not related to surface processes
Prevalencija infekcije Neisseriom gonorrhoeae ili Chlamydiom trachomatis kod akutnoga mukopurulentnog cervicitisa
The aim of this study was to determine the incidence of N. gonorrhoae (NG) and/or C. trachomatis (CT) in acute mucopurulent cervicitis (MPC). The study included 617 non-pregnant women with MPC, who had not been receiving any antimicrobial treatment. The average age of patients was 22.2 years. There were no statistically significant differences according to place of residence, education, and marital status. Samples for laboratory analysis were collected using a routine procedure; NG was identified using the cytochrome oxidase test and Gram staining. CT was isolated on McCoy cell culture and stained with Lugol solution. NG was isolated in three women (0.8 %) and CT in 58 women (9.4 %). Fifty-six of the CT-positive patients were nullipara and only two were unipara. All NG-positive patients were also nullipara. The mean number of sexual partners was 2.2 in all study subjects, 2.4 in CT-positive subjects, and 2.9 in NG-positive subjects. Vaginal discharge purity according to Schröder was significantly deteriorated in CT-positive patients (p=0.011). When asked about the use of contraceptives, as many as 32.7 % patients answered that they did not use any protection, 39 % women used the rhythm method and coitus interruptus, 20 % were taking oral contraceptives, 6.1 % used mechanical devices, and 1.9 % used chemical protection. Previous acute and chronic pelvic infl ammatory diseases correlated with MPC (p<0.01). Our statistical analysis suggests that chlamydial infection significantly reduces the purity of vaginal discharge, which is more pronounced in nulliparae. Pap smear was not specific enough to demonstrate chlamydial infection. In view of the MPC findings, the prevalence of CT and NG infection is low.Cilj istraživanja jest utvrditi koincidenciju N. gonorrhoae (NG) i/ili C. trachomatis (CT) u akutnim mukopurulentnim cervicitisima (MPC). Istraživanje je provedeno na populaciji 617 žena izvan trudnoće koje prethodno nisu uzimale antimikrobnu terapiju. NG i CT su izolirane iz obrisaka vrata maternice primjenom standardnih metoda. NG je transportirana na selektivnoj hranjivoj podlozi i identificirana citokrom-oksidaznim testom bojenjem po Gramu. CT je izolirana McCoyevom staničnom kulturom nakon bojenja Lugolovom otopinom. NG je izolirana u tri ispitanice (0,8 %), a CT u 58 ispitanica (9,4 %). Srednja dob bolesnica iznosila je 22,2 godine. Školovanje i bračno stanje nisu statistički značajno utjecali na rezultate istraživanja. Među bolesnicama s izoliranom CT prevladavaju nulipare, a u slučaju NG sve su pozitivne bolesnice također bile nulipare. Srednja vrijednost broja partnera za čitavu populaciju iznosi 2,2. Bolesnice s potvrđenom CT imale su prosječno 2,4, a one s potvrđenom NG 2,9 partnera. Vrijednost određivanja stupnja čistoće rodničkog iscjetka po Schroderu značajno je povišena u CT-pozitivnih bolesnica (p=0.011). Utvrđeno je da 32.7 % ispitanica uopće nije koristilo kontracepciju, dok je većina (39 %) rabila ritmičke metode i prekinuti snošaj. Preostale ispitanice uzimale su oralne kontraceptive (20 %), mehaničku zaštitu (6,1 %) ili lokalne kemijske kontraceptive (1,9 %). Također je dokazano da prethodna akutna i kronična zdjelična upalna bolest korelira s MPC-om (p<0.01). Zaključeno je da klamidijska infekcija statistički značajno korelira sa stupnjem čistoće rodničkog iscjetka, posebice u nulipara. Papanicolaouov razmaz nije specifičan u određivanju klamidijske infekcije. Rezultati istraživanja pokazuju da je učestalost klamidijske i gonokokne infekcije ipak relativno niska u odnosu na nalaz MPC-a
The clinical diagnosis of pelvic inflammatory disease – reuse of electronic medical record data from 189 patients visiting a Swedish university hospital emergency department
BACKGROUND: The pelvic inflammatory disease (PID) diagnosis is mostly based on clinical findings. However, few studies have examined the clinical basis for the diagnostics of PID, which was the aim of this study. METHODS: A retrospective study was performed of 189 out-patients diagnosed as having PID at the obstetric and gynecological emergency department of a Swedish university hospital. Data on symptoms, signs, pelvic examination and laboratory tests were extracted from the electronic medical records in comparison with the diagnostic criteria of the PID Guideline of the US Center of Disease Control from 2002 (CDC 2002 Guidelines). RESULTS: Eight symptoms in varying combinations were associated with the PID diagnosis. Most of them are mentioned in the CDC 2002 Guidelines. Detected rates of C. Trachomatis (CT) and N. Gonorrhoeae (NG) were 5% and 0%, respectively, among the tested patients (CT = 52% and NG = 12%). The C-reactive protein was normal in the majority of tested patients. CONCLUSION: The clinical basis for the diagnostics of PID was largely in accordance with the criteria in the CDC 2002 Guidelines. The limited number of CT tests performed is somewhat disappointing, considering the fact that effective disease prevention includes widespread CT screening. Further studies in different settings are needed in order to analyze how the testing rate for CT can be improved in clinical praxis
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