We demonstrate, by numerical solution of Maxwell's equations, near-perfect solar light-trapping and absorption over the 300-1100 nm wavelength band in silicon photonic crystal (PhC) architectures, amenable to fabrication by wet-etching and requiring less than 10 lm (equivalent bulk thickness) of crystalline silicon. These PhC's consist of square lattices of inverted pyramids with sides comprised of various (111) silicon facets and pyramid center-to-center spacing in the range of 1.3-2.5 lm. For a wet-etched slab with overall height H ¼ 10 lm and lattice constant a ¼ 2.5 lm, we find a maximum achievable photo-current density (MAPD) of 42.5 mA/cm 2 , falling not far from 43.5 mA/cm 2 , corresponding to 100% solar absorption in the range of 300-1100 nm. We also demonstrate a MAPD of 37.8 mA/cm 2 for a thinner silicon PhC slab of overall height H ¼ 5 lm and lattice constant a ¼ 1.9 lm. When H is further reduced to 3 lm, the optimal lattice constant for inverted pyramids reduces to a ¼ 1.3 lm and provides the MAPD of 35.5 mA/cm 2. These wetetched structures require more than double the volume of silicon, in comparison to the overall mathematically optimum PhC structure (consisting of slanted conical pores), to achieve the same degree of solar absorption. It is suggested these 3-10 lm thick structures are valuable alternatives to currently utilized 300 lm-thick textured solar cells and are suitable for large-scale fabrication by wet-etching. V
Introduction: Sarcomas of the ovary can either be histologically pure or can represent components of a more complex tumor. Ovarian angiosarcomas are rare, and probably arise from carcinosarcomas, teratomas or the rich ovarian vasculature. To date, only two small case series have been published, one with four cases and the other with seven. Case presentation: A 41-year-old Saudi woman presented to our gynecological clinic with abnormal vaginal bleeding. The initial clinical diagnosis was left ovarian cyst. The results of the remainder of her abdominopelvic examination were normal. Peri-operatively, the left ovarian mass resembled a hemorrhagic solid tumor. It was sent for frozen sectioning, which revealed it was an undifferentiated neoplasm. The final histopathological examination showed a vascular neoplasm showing vasoformative arborizing channels of variable sizes and shapes lined by atypical endothelial cells with intact capsule. Areas of necrosis were seen, along with fused anastomosing solid vascular area. She was diagnosed as having an angiosarcoma of intermediate grade, International Federation of Gynecology and Obstetrics stage IA. Conclusions: Patients with ovarian angiosarcomas most commonly present with abdominal pain, however some patients present with distant metastases, often in the lungs. Spread beyond the ovary is present at the time of diagnosis in most reported cases, with disease progression within less than a year after diagnosis. Cases of advanced stage disease behave aggressively and demonstrate poor response to surgery and chemotherapy, with an overall poor prognosis. They have a tendency for local recurrence and metastases, and prognosis is hence poor; the reported five-year survival rate is 10 percent to 35 percent, however, cases confined to the ovary have survived up to nine years.
Hemangiopericytoma is a rare vascular tumour of infants. Although generally considered to be benign, local recurrence and metastases can occur. Herein, we report on two full term girls, delivered with lumbosacral swelling and left thigh swelling respectively. Complete surgical excision with safety margins was performed for each lesion. Histologic examination of both lesions showed picture of infantile hemangiopericytoma. There is no evidence of local recurrence or distant metastasis during last 20 and 17 months for 1 st case and 2 nd case respectively. In conclusion; most infantile hemangiopericytoma follow a benign course. Rarely these tumours behave aggressively with local infiltration, recurrences and even distant metastases. Careful follow up is therefore essential.
Background: Endoscopic ultrasonography (EUS) is well-established, highly accurate clinical diagnostic test for detection and staging of gastrointestinal tract lesions and related organs. The addition of endoscopic guided fine needle aspiration cytology (EUS-FNAC) has improved the performance characteristics of EUS. Aim: Evaluate the validity of EUS-FNAC in diagnosis of gastrointestinal tract lesions and related organs and assess predictive factors for an accurate EUS-FNAC diagnosis. Methods: Our study included cytological sampling from one hundred sixty-six lesions obtained from gastrointestinal tract and related organs. Factors affecting EUS-FNA accuracy were analyzed. The histopathological results or clinical follow-up were used as the gold standard method. Results: Samples were obtained from: pancreatic masses (n = 80), gastric masses (n = 34), lymph nodes (n = 22), hepatobiliary masses (n = 18) and rectal masses (n = 2). Statistical analysis of sensitivity, specificity, Positive Predictive Value, Negative Predictive Value, and diagnostic accuracy of EUS alone was 80.4%, 51.6%, 75.8%, 76.2% and 75.9% respectively. The sensitivity, specificity, positive predictive value and negative predictive value of EUS-FNAC are 78.8%, 96.8%, 97.6% and 73.2% respectively. Addition of FNAC to EUS improved diagnostic accuracy to 85.5%. Positive statistical association was present between cytological adequacy and adequate cell block preparations, larger lesion size, presence of rapid on site evaluation (ROSE) and obtaining at least two passes from target lesion. Conclusions: EUS is valuable diagnostic and cost effective tool for gastrointestinal tract lesions and related organs when combined with FNAC.
Aim of the work: The aim of this study was to determine the prevalence of the cervical cellular Abnormalities using liquid based thin-layer preparations as screening test for women who attended the gynaecology outpatient clinic at King Abdul Aziz Specialist Hospital, Taif, Saudi Arabia. Material and method: In this retrospective chart review study, we reviewed the records and data of all women for whom liquid base cytological studies were performed as screening test to detect the cervical cellular abnormalities at King Abdul Aziz Specialist Hospital, Taif, Saudi Arabia from June 2010 to June 2012. Results:The total number of women for whom liquid base, thin-layer cytological studies were performedwas 2168 patients 79.9% of them were symptomatic. The mean age was 38.6 years. Liquid based thin-layer preparations were used for all patients. Cervical abnormality was seen in 25.6% of the patients, of which 6.5% were malignant or premalignant and 19.1% were of benign nature. Conclusion: Liquid-based, thin-layer cytology reduces sampling and preparation errors of the conventional smear; however, screening should include human papilloma virus (HPV), DNA testing to increase the sensitivity and specificity of primary screening.
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