832 research outputs found
Planning, creating and documenting a NASTRAN finite element model of a modern helicopter
Mathematical models based on the finite element method of structural analysis as embodied in the NASTRAN computer code are widely used by the helicopter industry to calculate static internal loads and vibration of airframe structure. The internal loads are routinely used for sizing structural members. The vibration predictions are not yet relied on during design. NASA's Langley Research Center sponsored a program to conduct an application of the finite element method with emphasis on predicting structural vibration. The Army/Boeing CH-47D helicopter was used as the modeling subject. The objective was to engender the needed trust in vibration predictions using these models and establish a body of modeling guides which would enable confident future prediction of airframe vibration as part of the regular design process
Modelatge de Pellets de Zeolita: Formulació i Procediments per Millorar les Propietats del Material com a Suport Catalític
Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2023, Tutors: Jordi Guilera Sala, Elena Martín MoralesThis study focuses on the shaping of zeolites for their application as catalyst supports for nickel-based catalysts in hydrocracking reactions. Zeolites are porous materials with high surface areas and unique structures that offer excellent catalytic properties. The shaping process involves forming zeolite particles into desired shapes to enable their application in industrial reactors and enhance their performance and stability in catalytic reactions. The effects of shaping parameters, including binder and plasticizer selection, shaping conditions, and post-treatment techniques, are investigated to achieve improved mechanical strength, porosity, and catalytic performance.
A rheological study has been carried out which has shown to reduce the work of formulation. It was found that the use of a plasticizer, such as methylcellulose, is necessary to achieve good extrusion. An inorganic binder, specifically boehmite, accompanied by a peptizer like acetic acid, is used to achieve good mechanical strength. Additionally, the effects of the alkaline desilication technique and the dealumination caused by the use of acetic acid on the zeolite structure are investigated. These treatments aim to modify the zeolite framework by reducing the silica and alumina content, respectively, in order to improve diffusion properties by increasing the pore size. The resulting shaped zeolites exhibit improved mechanical strength and increased pore siz
Secretory Carcinoma of Male Breast: Case Report and Review of the Literature
Secretory carcinoma is a rare low-grade breast carcinoma, initially termed “juvenile breast cancer,” but it is now known to occur in adults of both sexes. It is the only epithelial tumor of the breast with a balanced translocation, t(12;15), that creates an ETV6-NTRK3 gene translocation. In this paper, a 19-year-old male patient has had a right breast mass for 9 years which suddenly increased in size with no evidence of palpable axillary lymph nodes. The mass was excised for frozen section and was diagnosed as malignant growth for simple mastectomy. Microscopic examination revealed the classical features of secretory carcinoma. The tumor cells were positive for EMA and S-100 protein and focally positive for cytokeratin and ER but negative for progesterone receptor, CD34, and CEA. Four months later the patient developed ipsilateral axillary lymph node enlargement, with lymph node metastases in five of the dissected 19 lymph nodes. The patient was treated with six courses of chemotherapy and radiotherapy. Conclusion. Though considered an indolent neoplasm, secretory carcinoma does metastasize to lymph nodes. Surgery in the form of mastectomy with axillary clearance is the treatment of choice. This paper includes a rare case report of secretory carcinoma in young male patient, with axillary lymph node metastasis in spite of the indolent nature that this tumor is known to display
PROTECTIVE AND CURATIVE EFFECTS OF FRESH ORANGE JUICE (CITRUS SINENSIS L.) SUPPLEMENTATION AGAINST LIVER INJURIES, HEPATIC LIPID, PROTEIN, AND DNAOXIDATIVE DAMAGE INDUCED CYCLOOXYGENASE-2/PROSTAGLANDIN E2 INFLAMMATORY PATHWAY IN FEMALE IRRADIATED RATS
Objective: Our study aimed to examine the protective and curative ability of fresh orange juice (OJ) (Citrus sinensis L.) to counteract the adverse side effects of ionizing radiation (IR) on hepatic tissues of female irradiated rats and that has not been studied in advance.
Methods: Forty-nine adult female Sprague-Dawley albino rats (170±5 g) were divided into four sets of 12 animals, except the healthy control group contained 10 rats only and the irradiated control group contained 15 rats and was divided as follow Group I: Healthy control; Group II: Irradiated control, rats receiving a single dose (20 gray absorbed dose [Gy]) of whole-body γ-rays; Group III: Protective group, rats received (5 ml OJ/kg body weight) once daily for 14 days and after 24 h exposed to irradiation; and Group IV: Curative group, then rats were submitted to irradiation than after 24 h, treated with (5 ml OJ/kg body weight) once every day for 14 successive days.
Results: Our results explored that fresh OJ contains significant amounts of antioxidants as flavonoids and polyphenols and consequently pre- or post-fresh OJ supplementation to female irradiated rats attenuated significantly (p≤0.05) hepatic lipid, protein, and DNA-oxidative damage, hepatic inflammation, and activated inflammatory cyclooxygenase-2/prostaglandin E2 pathway, liver fibrosis, impaired liver functions, and hepatic lipid metabolism when compared with irradiated control rats. Furthermore, fresh OJ improved significantly (p≤0.05) the hepatic antioxidant capacity in protective and curative groups in comparison with the irradiated control group.
Conclusion: The current research illustrated that fresh OJ may improve and normalize the various hepatic biochemical abnormalities resulted from irradiation due to its high content of active constituents of flavonoids and polyphenols. It is advised for people who exposed to IR, especially females, to consume about (5 ml OJ/kg body weight) before exposure as the most significant improvements were recorded in the protective group that supplemented with OJ before irradiation
Immunohistochemical Expression of Fibroblast Growth Factor Receptor 3 and Cyclooxygenase-2 in Urinary Bladder Carcinomas with Correlation of Schistosomiasis in Egyptian Patients
BACKGROUND: In Egypt, schistosomal infestation is a leading cause of bladder cancer. A mutation in the fibroblast growth factor receptor 3 (FGFR-3) gene is the most common and most specific genetic abnormality in bladder cancer. Similarly, cyclooxygenase-2 (COX-2) is an inducible, pro-inflammatory enzyme with previous studies showing higher expression in schistosomal-associated bladder cancer.
AIM OF THE STUDY: The aim of the study was to evaluate the immunohistochemical expression of FGFR3 and COX2 in bladder carcinoma and correlates their expression to the associated schistosomal infestation to implicate possible therapeutic treatments.
MATERIALS AND METHODS: This retrospective study included a total of 90 cases of archived, formalin fixed, paraffin-embedded tissue blocks that included variable subtypes and grades of urothelial carcinomas. Immunohistochemistry for expression of FGFR-3 and COX2 was performed using a standard avidin-biotin-peroxidase system.
RESULTS: About 73.3% of the total cases (66 cases) showed variable positive reactivity for FGFR3, of which 33.3% (22 cases) were associated with bilharzia infection. A statistically significant correlation was detected between FGFR-3 and tumor size, grade, histologic subtype, LN status, lymphovascular invasion, and stage. About 83.3% of the total cases (75 cases) showed variable positive immunoreactivity for COX-2, of which 37.3% (28 cases) were bilharzial-associated. A positive correlation was established between COX-2 and grade, concomitant in situ changes and cases associated with bilharzia infection.
CONCLUSION: FGFR-3 can be used as a prognostic marker for low-grade urothelial tumors. Results also portray that COX-2 has an inflammatory inciting role in bladder carcinoma development, especially in patients with a history of schistosomiasis (bilharziasis). Both COX-2 and FGFR-3 should be explored further for its use alone or in combination with conventional treatment, to reduce the recurrence rate and progression of superficial (low grade) tumors
“Clean” Liquid Helium
Liquid helium is the coldest fluid that exists in nature. By virtue of this fact, any unwanted substance present in liquid helium, that is, any impurity, will be “frozen” and will be in solid form. In practice, these solid impurities can be easily eliminated to obtain “optically clean” liquid. However, even “optically clean” filtered liquid helium may contain a non-negligible quantity of molecular hydrogen. These minute traces of molecular hydrogen are the causes of a known problem worldwide: the blockage of capillary tubes in helium evaporation cryostats. This problem seriously affects a wide range of cryogenic equipment used in low-temperature physics research at a considerable operational cost increase. In this chapter, we propose an underlying mechanism for this effect and provide a definitive solution by means of production of hydrogen-free liquid helium, that is, not only “optically clean” liquid helium but completely “clean” liquid helium. Moreover, basic superfluidity research studies could benefit from the availability of “clean” liquid helium
Prevalence of metabolic syndrome and cardiovascular risk factors among voluntary screened middle-aged and elderly Egyptians
Background: Central obesity and diabetes mellitus are recorded at high percentages among Egyptians. The aim of this study is to determine the prevalence of metabolic syndrome (MetS) and cardiovascular risk factors among a group of middle-aged and elderly Egyptians.
Methods: Our study included 220 middle-aged and senior Egyptians voluntary screened in an Egyptian private hospital with 800-bed capacity. Detailed medical history was obtained from all subjects, followed by clinical examination with weight and height measurement, body mass index calculation, waist hip ratio and arterial blood pressure measurement. Laboratory investigations done were complete blood picture, lipid profile and fasting blood glucose measurements. The diagnosis of MetS was based on the American Heart Association/Updated NCEP ATP III criteria. Cardiovascular risk assessment was calculated for each subject based on the Framingham/ATP III criteria.
Results: The prevalence of MetS in this study was of 55% among the whole sample, 85.6% among diabetics and 76.6% among hypertensive patients. Based on Framingham scoring system, 48.2% of the sample had moderate to high risk of developing cardiovascular disease. Odds ratio for patients with MetS for developing cardiovascular disease in the next 10 years was 2.8 (95% confidence interval: 1.6-4.8).
Conclusion: The high prevalence of MetS among middle-aged and elderly Egyptians with the documented high prevalence of chronic diseases in Egypt calls for a nationwide screening program to detect MetS and tackle preventive strategies to face the epidemic of obesity and outcomes of MetS, particularly cardiovascular diseases
Accesibilidad y movilidad en el municipio de Aínsa-Sobrarbe. Perspectiva social y de comunicación con la Administración Local
La Administración como gestor de servicios públicos no siempre tiene la perspectiva real de las problemáticas del ciudadano. La accesibilidad y libre desplazamiento son dos elementos fundamentales para aquellos con diversidad funcional por razones de movilidad. Aínsa es uno de los municipios más bonitos de España, reconocido internacionalmente. Los gestores públicos de este pueblo deberían de adelantarse a los problemas no solo de los ciudadanos del municipio sino de aquellos turistas que deciden que Aínsa sea su lugar de vacaciones. El presente estudio tiene como finalidad valorar la percepción social, de residentes y turistas, sobre la accesibilidad y movilidad en Aínsa. Para la erradicación de las barreras existentes, las vías alternativas para solucionar el problema, la oferta de un turismo accesible, así como la propuesta de un plan de sensibilización y formación sobre el tema a la población habitante de dicha localidad. Todo ello desde una perspectiva integradora y una triangulación metodológica.<br /
Immunohistochemical Study of Androgen Receptor Expression in Estrogen Receptor-Negative Invasive Breast Carcinoma and its Relation with Clinicopathologic Factors
BACKGROUND: Estrogen receptor (ER)-negative breast carcinomas lack the expression of ER and they have no targeted hormone therapies. The androgen receptor (AR) is a newly emerge biomarker. Detecting AR in these tumors may provide a target for future therapies.
AIM: The aim of the study is to examine the immunohistochemical expression profiles of AR protein in ER-negative invasive breast carcinomas and to assess the relation between AR expression and the clinicopathologic factors such as age, tumor size, tumor grade, tumor type, immunohistochemical type, lymph node status, and Ki67 expression.
METHODS: Sixty paraffin blocks of ER-negative invasive breast carcinoma cases were stained immunohistochemically by AR. Positive expression was defined as ≥1% nuclear staining.
RESULTS: AR positivity was detected in 55% of the studied cases. The positive cases were scored by H-score with a median=117, and a range of 3–285 and by Allred score with a median=7, and a range of 3-8. AR is expressed in 60.9% of triple-negative breast carcinoma cases. AR expression was higher in older age, and there were significant positive correlations between the degree of AR expression (AR%, AR intensity, and H-score) and age (p=0.050, 0.007, 0.033, respectively). There was non-significant negative correlation between Ki67% and the degree of AR expression (AR%, AR intensity, H-score, and Allred score). Regarding different histological types, tumor grade, tumor size, lymph node status, and immunohistochemical types, there was no significant difference between AR positive and AR negative cases.
CONCLUSION: AR is frequently expressed in ER-negative invasive breast carcinoma; especially in older age, and in a large number of triple-negative subtypes. This may give chance to benefit from future AR target therapy. We recommend further research work on AR expression in the special histologic subtypes of ER-negative breast carcinoma and in the triple negative group
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