345 research outputs found
Self-scheduling of wind-thermal systems using a stochastic MILP approach
In this work a stochastic (Stoc) mixed-integer linear programming (MILP) approach for the coordinated trading of a price-taker thermal (Ther) and wind power (WP) producer taking part in a day-ahead market (DAM) electricity market (EMar) is presented. Uncertainty (Uncer) on electricity price (EPr) and WP is considered through established scenarios. Thermal units (TU) are modelled by variable costs, start-up (ST-UP) technical operating constraints and costs, such as: forbidden operating zones, minimum (Min) up/down time limits and ramp up/down limits. The goal is to obtain the optimal bidding strategy (OBS) and the maximization of profit (MPro). The wind-Ther coordinated configuration (CoConf) is modelled and compared with the unCoConf. The CoConf and unCoConf are compared and relevant conclusions are drawn from a case study
Developing an Efficient Secure Query Processing Algorithm on Encrypted Databases using Data Compression
Distributed computing includes putting aside the data utilizing outsider storage and being able to get to this information from a place at any time. Due to the advancement of distributed computing and databases, high critical data are put in databases. However, the information is saved in outsourced services like Database as a Service (DaaS), security issues are raised from both server and client-side. Also, query processing on the database by different clients through the time-consuming methods and shared resources environment may cause inefficient data processing and retrieval. Secure and efficient data regaining can be obtained with the help of an efficient data processing algorithm among different clients. This method proposes a well-organized through an Efficient Secure Query Processing Algorithm (ESQPA) for query processing efficiently by utilizing the concepts of data compression before sending the encrypted results from the server to clients. We have addressed security issues through securing the data at the server-side by an encrypted database using CryptDB. Encryption techniques have recently been proposed to present clients with confidentiality in terms of cloud storage. This method allows the queries to be processed using encrypted data without decryption. To analyze the performance of ESQPA, it is compared with the current query processing algorithm in CryptDB. Results have proven the efficiency of storage space is less and it saves up to 63% of its space.
EFFECT OF SOME HORMONAL TREATMENTS ON GROWTH AND CHEMICAL COMPOSITION OF RHAPHIOLEPIS UMBELLATA SHRUB
A pot experiment was consummated on Rhaphiolepis umbellata seedlings grown under seran greenhouse at Al-Zohriya Garden, Hort. Res. Inst., ARC, Giza, Egypt during the two consecutive seasons 2017 and 2018, to study effects of five foliar spray treatments of a mixture containing three growth regulators (PGR), at the same concentration for each, on plant growth and chemical composition. The three-tested PGR were NAA, GA3 and BA, while the five concentrations for each were 0 (control treatment), 100, 200, 300 and 400 ppm. Obtained results indicated that, generally, all recorded vegetative and root growth traits; i.e., plant height, stem diameter, numbers of branches and number of leaves/plant, leaf area, root length and number of roots/plant increased significantly under the effect of all tested PGR treatments, compared to the control plants. The highest increases in this regard were recorded in plants sprayed with PGR at 200 ppm, while the least values were found in the untreated control plants, followed by plants sprayed with the highest PGR concentration of 400 ppm for the two seasons. The same trend was noticed in respect of leaf chemical constituents, as plants that recorded the highest vegetative and root growth (treated 200 ppm PGR) also contained the highest values of total chlorophyll and carotenoids (mg/g f.w.) as well as percentages oftotal carbohydrate, N, P and K in leaf tissues. Accordingly, it could be recommended to apply the mixture of these three growth regulators 200 ppm on seedlings of Rhaphiolepis umbellata, two times monthly during the growing season to get the best plant growth and quality
Creating Customized Hip-Spacers Using PMMA-Based Green Composites to Fulfill Specific Needs of Individuals with Disabilities
In the context of replacing damaged artificial hip joints, a common practice involves using antibiotic-infused bone cement as a spacer. However, the mechanical properties of polymethyl methacrylate (PMMA), which is commonly used for spacers, have certain limitations. To address this issue, the present study suggests incorporating a natural filler, specifically coffee husk, as a reinforcement for PMMA. Different composite samples were prepared by varying the weight fractions of coffee husk, and their mechanical properties were assessed. The results indicated that the inclusion of coffee husk particles in PMMA led to improvements in compressive strength, hardness, and stiffness. Furthermore, a finite element model was constructed and analyzed to evaluate the stress experienced on the spacer’s surface (load-carrying capacity), yielding findings consistent with the experimental results
Role of SIRT-1 Gene in The Development of Diabetic Retinopathy
Background: Diabetes mellitus (DM) has had a consistent increase in global prevalence. A common microvascular disease associated with diabetes is diabetic retinopathy (DR). As a complex, progressive, as well as asymptomatic neurovascular consequence of DM, DR is the leading cause of vision impairment and blindness in working-age people. The presence of retinal neovascularization classifies diabetic retinopathy (DR) as proliferative, non-proliferative, or diabetic macular edema.
Aim of the Study: to evaluate the level of expression of mRNA sirt1- gene in cases of type 2 DM that have retinopathy or vulnerable to it.
Patients and Methods: In this research, 60 cases (15 patients with diabetic retinopathy, 15 diabetic cases without retinopathy (PDR), and 30 non-diabetic controls) were recruited. SIRT1 mRNA expression from the two groups was analyzed. Notably, patients with DR exhibited a decrease in the expression of SIRT1 mRNA. ELISA was also used to measure the levels of IL-17 expression in the serum. The results showed that the sera of people with DR had higher levels of IL-17 expression than the sera of healthy people.
Results: The findings of this research indicate that imbalanced IL-17 & SIRT1 expression levels may play a role in the etiology of DR, with SIRT1 potentially exerting a protective effect by suppressing IL-17 production
EFFECT OF PRE-SOWING TREATMENTS, SEED ORIENTATION AND THEIR INTERACTIONS ON SEED GERMINATION AND SEEDLING GROWTH OF AFRICAN MAHOGANY (KHAYA SENEGALENSIS (DESR.) A. JUSS) TREE
An investigation was consummated under shade condition at the nursery of Orman Botanical Garden, Giza, Egypt during 2020 and 2021 seasons to study the effect of pre-sowing treatments; i.e. seeds without any treatment (as control), soaking in tap water for 24 h at ambient temperature and soaking in hot water (70-80 °C) for 24 h, seed orientation treatments; horizontal with the micropyle oriented laterally and vertical with the micropyle positioned either upwards or downwards and their interactions on germination characters and seedling growth traits of African mahogany timber tree (Khaya senegalensis (Desr.) A. Juss) seeds. The results indicated that seeds soaked in hot water for 24 h failed to germinate in both seasons, while those soaked in tap water at room temperature for 24 h gave the highest percent of germination, the least No. days to either maximum or 50% germination as well as the best means of germination rate index, vigour index, seed viability and plumule length compared to control in the two seasons. Horizontal sowing method recorded the maximal germination percent, quickest germination, strongest vigour index and seed viability as well as the longest plumule length and followed by vertical one, in which the micropyle oriented upwards. So, the best results at all were obtained from combining soaking the seeds in tap water treatment and positioned them horizontally. A similar trend to that of germination characteristics was also occurred regarding seedling growth parameters. Accordingly, it can be proposed to soak Khaya senegalensis seeds in ordinary water pre-sowing for 24 h at ambient temperature and embedding them horizontally at 2 cm depth with the micropyle positioned laterally to obtain better germination and the best growth traits of the seedling
Liver transplantation is a preferable alternative to palliative therapy for selected patients with advanced hepatocellular carcinoma
Background: Patients with hepatocellular carcinoma (HCC) beyond the traditional criteria (advanced HCC) are typically offered palliation, which is associated with a 3-year survival rate lower than 30%. This study aimed to describe the outcomes for a subset of patients with advanced HCC who satisfied the Extended Toronto Criteria (ETC) and were listed for liver transplantation (LT).
Materials & Methods: All patients listed in the Toronto liver transplant program with HCC beyond both the Milan and University of California, San Francisco criteria were included in this study. Data were extracted from the prospectively collected electronic database. All radiological images were reviewed by two independent radiologists. The primary endpoint was patient survival.
Results: Between January 1999 and August 2014, 96 patients with advanced HCC were listed for LT, and 62 (65%) of these patients received bridging therapy while on the waiting list. Bridging therapy led to a significant reduction in tumor progression (p=0.02) and tumor burden (p <0.001). The majority of those listed underwent LT (n=69, 72%). Both tumor progression on waiting list (HR 4.973 [1.599 – 15.464], p=0.006) and peak AFP ≥400ng/ml (HR 4.604 [1.660 – 12.768], p=0.003) were independently associated with waiting list dropout. Post-LT HCC recurrence occurred in 35% (n=24). Among those with HCC recurrence, survival was significantly better for those who received curative treatment (p=0.004). The overall actuarial survival rates from the listing were 76% at 1 year, 56% at 3 years, and 47% at 5 years, and the corresponding rates from LT were 93%, 71%, and 66%.
Conclusion: LT provides significantly better survival rates than palliation for patients with selected advanced HCC
Functional and MRI follow-up after reconstruction of chronic ruptures of the Achilles tendon Myerson type III using the triple-loop plantaris tendon wrapped with central turndown flap: a case series
BACKGROUND: Reconstruction of chronic ruptures of the Achilles tendon poses a great challenge for the orthopaedic surgeon both technically and functionally. The aim of this study was to assess the results of a new technique for reconstruction of chronic Achilles tendon ruptures with defects longer than 5 cm using the triple-loop plantaris tendon autograft wrapped in a central turndown flap from the proximal portion of the Achilles tendon. PATIENTS AND METHODS: Eighteen patients (14 female and 4 male; mean age, 40.7 years), having chronic ruptures of the Achilles tendon Myerson type III, were enrolled in this study. The mean follow-up period of our patients was 21.8 months. All patients were assessed via the following parameters: lag of interference since the first complaint, length of the defect, length of the turndown flap and length of the harvested plantaris tendon, surgery time, complications, active range of motion at the ankle and the final score. Average values were presented as means. Independent sample t test, Mann Whitney test, paired sample t test and Pearson’s correlation coefficient were used to evaluate the clinical and functional results. The results were considered statistically significant if a P value was <0.05. To analyse the time course of the gap following surgery, the data from the first MRI session were compared with those from the second and third sessions using the Wilcoxon’s signed rank test. In addition, the paired data of the tendon gap disappearance rate between T1-weighted and T2-weighted images were also compared using the McNemar test. RESULTS: The mean preoperative American Orthopaedic Foot and Ankle Society score was 62.2 points while at the patients’ last follow-up, the mean postoperative score was 94.9 points. The results of this study confirmed that both the Achilles tendon healing and tendon gap disappearance have been perceived with higher sensitivity in T2-weighted images than in T1-weighted images. CONCLUSIONS: We believe that this new technique is biologic, synchronous and reliable in cases of chronic Achilles tendon ruptures with defects longer than 5 cm
Effect of Synthesized Titanium Dioxide Nanofibers Weight Fraction on the Tribological Characteristics of Magnesium Nanocomposites Used in Biomedical Applications
Biomedical applications, such as artificial implants, are very significant for the disabled due to their usage in orthopedics. Nevertheless, available materials in such applications have insufficient mechanical and tribological properties. The current study investigated the mechanical and tribological properties of a biomedical metallic material, magnesium (Mg), after incorporating titanium dioxide nanofibers (TiO2) with different loading fractions. The TiO2 nanofibers were synthesized using the electrospinning technique. The ball-milling technique was utilized to ensure the homogenous distribution of TiO2 nanofibers inside the Mg matrix. Then, samples of the mixed powder with different loading fractions of TiO2 nanofibers, 0, 1, 3, 5, and 10 wt.%, were fabricated using a high-frequency induction heat sintering technique. The physicomechanical and tribological properties of the produced Mg/TiO2 nanocomposites were evaluated experimentally. Results showed an enhancement in mechanical properties and wear resistance accompanied by an increase in the weight fraction of TiO2 nanofibers up to 5%. A finite element model was built to assess the load-carrying capacity of the Mg/TiO2 composite to estimate different contact stresses during the frictional process. The finite element results showed an agreement with the experimental results
Investigation of the Mechanical and Tribological Behavior of Epoxy-Based Hybrid Composite
The main target of this study is to evaluate the impact of hybrid reinforcement using Al2O3 nanoparticles and graphite on the epoxy nanocomposites’ mechanical and tribological properties. Various weight fractions of the reinforcement materials, ranging from 0 to 0.5 wt.%, were incorporated into the epoxy. The aim is to enhance the characteristics and durability of the polymers for potential utilization in different mechanical applications. The addition of hybrid additives consisting of Al2O3 nanoparticles and graphite to the epoxy resin had a noticeable effect on the performance of the epoxy nanocomposites. The incorporation of these additives resulted in increased elasticity, strength, toughness, ductility, and hardness as the concentration of reinforcement increased. The enhancement in the stiffness, mechanical strength, toughness and ductility reached 33.9%, 25.97%, 25.3% and 16.7%, respectively. Furthermore, the frictional tests demonstrated a notable decrease in both the coefficient of friction and wear with the rise of the additives’ weight fraction. This improvement in the structural integrity of the epoxy nanocomposites led to enhanced mechanical properties and wear resistance. The SEM was utilized to assess the surfaces of tested samples and provide insights into the wear mechanism
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