Hybrid active force control for fixed based rotorcraft

Disturbances are considered major challenges faced in the deployment of rotorcraft unmanned aerial vehicle (UAV) systems. Among different types of rotorcraft systems, the twin-rotor helicopter and quadrotor models are considered the most versatile flying machines nowadays due to their range of applications in the civilian and military sectors. However, these systems are multivariate and highly non-linear, making them difficult to be accurately controlled. Their performance could be further compromised when they are operated in the presence of disturbances or uncertainties. This dissertation presents an innovative hybrid control scheme for rotorcraft systems to improve disturbance rejection capability while maintaining system stability, based on a technique called active force control (AFC) via simulation and experimental works. A detailed dynamic model of each aerial system was derived based on the Euler–Lagrange and Newton-Euler methods, taking into account various assumptions and conditions. As a result of the derived models, a proportional-integral-derivative (PID) controller was designed to achieve the required altitude and attitude motions. Due to the PID's inability to reject applied disturbances, the AFC strategy was incorporated with the designed PID controller, to be known as the PID-AFC scheme. To estimate control parameters automatically, a number of artificial intelligence algorithms were employed in this study, namely the iterative learning algorithm and fuzzy logic. Intelligent rules of these AI algorithms were designed and embedded into the AFC loop, identified as intelligent active force control (IAFC)-based methods. This involved, PID-iterative learning active force control (PID-ILAFC) and PID-fuzzy logic active force control (PID-FLAFC) schemes. To test the performance and robustness of these proposed hybrid control systems, several disturbance models were introduced, namely the sinusoidal wave, pulsating, and Dryden wind gust model disturbances. Integral square error was selected as the index performance to compare between the proposed control schemes. In this study, the effectiveness of the PID-ILAFC strategy in connection with the body jerk performance was investigated in the presence of applied disturbance. In terms of experimental work, hardware-in-the-loop (HIL) experimental tests were conducted for a fixed-base rotorcraft UAV system to investigate how effective are the proposed hybrid PID-ILAFC schemes in disturbance rejection. Simulated results, in time domains, reveal the efficacy of the proposed hybrid IAFC-based control methods in the cancellation of different applied disturbances, while preserving the stability of the rotorcraft system, as compared to the conventional PID controller. In most of the cases, the simulated results show a reduction of more than 55% in settling time. In terms of body jerk performance, it was improved by around 65%, for twin-rotor helicopter system, and by a 45%, for quadrotor system. To achieve the best possible performance, results recommend using the full output signal produced by the AFC strategy according to the sensitivity analysis. The HIL experimental tests results demonstrate that the PID-ILAFC method can improve the disturbance rejection capability when compared to other control systems and show good agreement with the simulated counterpart. However, the selection of the appropriate learning parameters and initial conditions is viewed as a crucial step toward this improved performance

Minimally Invasive Approach in Surgical Management of Renal Neoplasms National Cancer Institute Experience

BACKGROUND: Minimally invasive nephrectomy is considered a technically challenging procedure requiring a long learning curve to reach acceptable warm ischemia time and perioperative complications. These minimally invasive techniques result in a shorter hospital stay and less post-operative pain. AIM: This study aims to demonstrate the National Cancer Institute experience regarding the benefits of laparoscopic and robot-assisted nephrectomy over open technique. METHODS: This is a retrospective descriptive cohort study including 62 patients with renal masses treated with nephrectomy whether partial, total or radical, 26 cases were treated by minimally invasive techniques (8 robotic and 18 laparoscopic), while 36 cases were treated by open technique. Inclusion criteria were patients between 20 and 70 years with renal neoplasm without renal vein thrombosis, with tumor stage T1 or T2 N0 M0. Exclusion criteria were patients with medical comorbidities that preclude surgical management or minimally invasive techniques and patients refusing surgery in general. RESULTS: Minimally invasive nephrectomy resulted in shorter hospital stay (mean hospital stay was 2.2 days for the minimally invasive group and 3.6 days for the open group) and less post-operative pain than open technique (p < 0.001 and = 0.002, respectively), while open technique resulted in shorter operation time (p = 0.039, mean operation time 147.8 min compared to 184.8 in the minimally invasive group). CONCLUSION: Minimally invasive nephrectomy (laparoscopic and robotic) resulted in less post-operative pain and shorter hospital stay compared to open technique despite consuming longer operation time which may be decreased by improving the learning curve of operating surgeons

Efficacy of Magnetic Field on Risk of Falling and Bone Mineral Density in Elderly Osteoporotic Women

Background: Osteoporosis, a prevalent condition affecting equally women and men, has been marked by reduced bone mass and structural degeneration. PEMFs promote bone formation, reduce inflammation, and improve bone remodeling by boosting osteoblast development and differentiation. Objective: The aim of this study was to examine the efficacy of pulsed electromagnetic field on bone mineral density and risk of falling in old women with osteoporosis. Methods: The study included sixty older women with osteoporosis. The subjects were separated into two groups: 30 in each one. Group A received pulsed electromagnetic field and closed chain exercise; and group B received the closed chain exercises. Results: A statistically significant improvement in the study group compared to the control group with percentage of improvement in femur BMD, lumbar BMD, risk of falling, BBS, ALP, VAS for L.L, VAS for back and OQLQ by 27.71 %, 27.84 %, 21.86 %, 21.64 %, 31.29 %, 54.06 %, 53.01 % and 33.45 % respectively. Conclusion: Pulsed Electro Magnetic Field (PEMF) is a significant intervention, and it is recommended to be a part of physical therapy & rehabilitation protocols of elderly osteoporotic women

Increased Risk of Hypoglycemia Following Roux-en-Y Gastric Bypass Surgery in Patients Without Diabetes: a Propensity Score-Matched Analysis.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) surgery is an effective treatment for obesity. However, the incidence and long-term risk of hypoglycemia after surgery in patients without diabetes remains unclear. This study aimed to investigate the prevalence of hypoglycemia following RYGB surgery in patients with obesity and without diabetes. METHODS: A retrospective cohort study was conducted using the TriNetX database. The study population included 15,085 patients with obesity (BMI ≥ 30 kg/m2) who underwent RYGB surgery and 3,200,074 non-surgical controls, all without a history of diabetes or GLP-1 receptor agonist use. Propensity score matching was performed to balance baseline characteristics. The primary outcome was the incidence of hypoglycemia, defined by ICD-10-CM codes or laboratory values (glucose ≤ 70 mg/dL). Cox regression analysis was employed to calculate hazard ratios (HR) and 95% confidence intervals (CI). RESULTS: In the overall study population, the risk of hypoglycemia was significantly higher in the RYGB group (18.70%, n = 2,810) compared to the control group (3.80%, n = 120,923; HR 4.3, 95% CI 4.14-4.46, p < 0.001). After propensity score matching (n = 14,916 per group), RYGB patients maintained an elevated risk (18.70%, n = 2,795) compared to matched controls (5.0%, n = 749; HR 3.7, 95% CI 3.44-4.05, p < 0.001). Time-series analysis revealed consistently higher hypoglycemia risk in the RYGB group, with hazard ratios ranging from 5.37 (95% CI 4.09-7.03) at 1 week to 3.75 (95% CI 3.45-4.06) at 10 years post-surgery (all p < 0.001). Subgroup analysis of RYGB patients who developed hypoglycemia showed a 30-day hospitalization rate of 21.3% and a mortality rate of 0.71%. CONCLUSION: RYGB surgery is associated with a significantly increased risk of hypoglycemia in patients with obesity and without diabetes, both in the short-term and long-term follow-up. These findings underscore the importance of monitoring and managing hypoglycemia in patients undergoing RYGB surgery, even in the absence of preexisting diabetes

Ceramide 24 Level in Hepatitis C Virus- Patients and Healthy Persons

Background: There are 170 million people in the globe living with hepatitis C virus (HCV) infection, which causes inflammation and hepatic fibrosis in various degrees. A portion of these patients will develop cirrhosis and other end-stage liver disease problems over the course of twenty to forty years. Low levels of serum ceramide 24 (Cer24) are linked to severe liver fibrosis and poor response to antiviral therapy in those with chronic HCV infection. Objective: This study was designed to assess level of ceramide 24 in chronic HCV and normal individuals. Subjects and Methods: The study was carried out as a case control study at Tropical Medicine Department, Clinical Pathology Department in Zagazig University Hospitals and at Viral Hepatitis Treatment Unit in Al-Ahrar Teaching Hospital. The study included 60 individuals who were divided into 2 groups. Group 1 included 30 case and group 2 was 30 healthy subjects as control. All patients were clinically evaluated, had routine laboratory investigations and measurements of circulating levels of ceramide 24. Abdominal ultrasonography was done. Results: Serum ceramide 24 level in HCV patients (cases) is 15.16 ± 6.93 while its level in normal individuals (control) is 65.01 ± 65.84. Conclusion: It was found that serum ceramide 24 level was significantly reduced in case group

Anomoeodus aegypticus n. sp. (Pisces, †Pycnodontiformes) from the late Cretaceous of the Dakhla Formation, Western Desert, Egypt

EnBased on a single right prearticular bone section with partial dentition collected from the lower part of the Beris member, Dakhla Formation (Egypt), dated to the Maastrichtian, the authors describe a new Pycnodont, Anomoeodus aegypticus. The planktonic foraminiferal assemblages indicate deposition in a marginal marine environment with open marine influx. The dental apparatus demonstrates the characteristic disposition of the teeth, which are typically semi-spherical, kidney-shaped and elliptical, as seen for the genus Anomoeodus. The new species is primarily characterised by the largest teeth not being those of the medial row (located near the symphysis; as seen for all Anomoeodus), but those of the primary lateral row.ItBasandosi su un osso pre-articolare destro frammentario, con dentatura parziale, raccolto dalla parte inferiore dei cosiddetti "strati di Beris" della Formazione di Dakhla (Egitto), datata al Maastrichtiano, gli autori descrivono il picnodonte Anomoeodus aegypticus n. sp. Il fossile è stato trovato in associazione con un'ampia varietà di vertebrati marini (mosasauri, plesiosauri, tartarughe marine, coccodrilli, denti di squalo, ossa e denti di pesci) e occasionali resti vegetali. Le associazioni di foraminiferi planctonici indicano la deposizione in un ambiente marino marginale, con afflusso sporadico dal mare aperto. L'apparato dentario descritto mostra la caratteristica disposizione dei denti, che sono peraltro tipicamente semisferici, allungati, reniformi, come si vede tipicamente nel genere Anomoeodus. La nuova specie è caratterizzata dal fatto che i denti di dimensioni maggiori non appartengono alla fila mediale (localizzati in prossimità della sinfisi), come avviene in tutti gli Anomoeodus, ma appartengono alla fila laterale primaria. Ulteriori caratteri sono: (i) I denti di maggiori dimensioni appartengono alla serie primaria laterale; (ii) assenza di diastema; (iii) bassissimo numero di serie dentarie preartcolari (tre); (iv) basso numero di elementi dentari per ciascuna serie prearticolare; (v) le due serie laterali (la primaria e la secondaria) formano fra loro un angolo diedro aperto buccalmente; (vi) la superfice occlusale è concava nei denti di entrambe le serie laterali (primaria e secondaria), convessa in quella dei denti della serie mediale. Anomoeodus aegypticus n. sp. ha le sue maggiori affinità anatomiche con Anomoeodus "specie B" descritto da Cooper and Mantill (2020) nel Cretaceo superiore del Marocco, che – pertanto – cade nella sinonimia della nuova specie Anomoeodus aegypticus

The impact of Oligo-miocene basaltic intrusions on the petroleum system in Gulf of Suez rift basin, Egypt: new insights into tikhermal maturity and reservoir quality

In recent years, the petroleum industry has prioritized the exploration of new and unconventional petroleum reservoirs. As a result, this study assessed the significance of basaltic intrusions from two key aspects: their impact on the thermal maturity of pre-rift source rocks and their potentiality as reservoirs. The present study attempts to integrate surface field investigations of basaltic dykes in Wadi Nukhul and Wadi Matulla as surface analogs with petroleum system modeling of pre-rift source rocks containing subsurface basaltic intrusions in the Abu Rudeis-Sidri field. Therefore, the fracture networks were observed in Wadi Nukhul and Wadi Matulla, suggesting that both the basaltic dykes and host rocks have interconnected fractures, which is critical for a high-quality reservoir of the dykes and efficient oil expulsion. As a result, the analysis of burial history, temperature, maturity, generation, transformation ratio, and expelled oil quantity revealed a significantly high value for basaltic intrusions. Moreover, the Abu Rudeis-Sidri field had a good petroleum system with thermally mature source rocks by basaltic intrusions. Furthermore, the fractured basaltic intrusions presented a high-quality oil reservoir well-sealed by the thick Rudeis Formation. Oil production has doubled since the discovery of this reservoir. This study introduces a novel approach to understanding the distribution pattern of basaltic intrusions in subsurface and surface analogs, which can serve as a model for exploring new potential unconventional basaltic reservoirs in the Gulf of Suez rift basin

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020