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THE INVARIANT OF IMMERSIONS UNDER ISOTWIST FOLDING
Mabrouk Salam El-Ghoul,Mohamed Esmail Basher 충청수학회 2005 충청수학회지 Vol.18 No.1
In this paper we will introduce all types of the isotwist foldings of a manifold M into itself. The limits of the isotwist foldings of a manifold are obtained. Also the relations between conditional retraction and this type of the folding are achieved. Finally the variant and invariant of the immersion under the type of folding are deduced.
Mabrouk Salem El-Ghoul,Mohamed Esmail Basher 충청수학회 2005 충청수학회지 Vol.18 No.2
In this paper, we introduced the tiling, for closed plane curves α(s), and we discussed the properties of tiling. Also if α(s) was arbitrary plane closed curve equipped by tiling ℑ then we studied the effect of retraction and tiling retraction on it.
Fibrin Sealant and Lipoabdominoplasty in Obese Grade 1 and 2 Patients
Mabrouk, Amr Abdel Wahab,Helal, Hesham Aly,Al Mekkawy, Soha Fathy,Mahmoud, Nada Abdel Sattar,Abdel-Salam, Ahmed Mohamed Korean Society of Plastic and Reconstructive Surge 2013 Archives of Plastic Surgery Vol.40 No.5
Background Ever since lipoabdominoplasty was first developed to achieve better aesthetic outcomes and less morbidity, the rate of seroma formation, especially in obese patients, has disturbed plastic surgeons. The aim of this study was to evaluate the effect of fibrin sealant in the prevention of seroma formation after lipoabdominoplasty in obese patients. Methods Sixty patients with a body mass index (BMI) between 30 and 39.9 were assigned randomly to 1 of 2 groups (30 patients each). Group A underwent lipoabdominoplasty with fibrin glue, while group B underwent traditional lipoabdominoplasty; both had closed suction drainage applied to the abdomen. The patients' demographics and postoperative complications were recorded. Seroma was detected using abdominal ultrasound examinations at two postoperative periods: between postoperative days 10 and 12 and, between postoperative days 18 and 21. Results The age range was 31 to 55 years ($38.5{\pm}9.5$ years) in group A and 25 to 58 years ($37.8{\pm}9.1$ years) in group B, while the mean BMI was 31.4 to 39.9 $kg/m^2$ (32.6 $kg/m^2$) in group A and 32.7 to 37.4 $kg/m^2$ (31.5 $kg/m^2$) in group B. In group A, the patients had a complication rate of 10% in group A versus 43% in group B (P<0.05). The incidence of seroma formation was 3% in the fibrin glue group but 37% in the lipoabdominoplasty-alone group (P<0.05). Conclusions Lipoabdominoplasty with the use of autologous fibrin sealant is a very effective method that significantly reduces the rate of postoperative seroma.
Clinical characteristics and outcomes of critically ill COVID-19 patients in Sfax, Tunisia
Mabrouk Bahloul,Sana Kharrat,Kamilia Chtara,Malek Hafdhi,Olfa Turki,Najeh Baccouche,Rania Ammar,Nozha Kallel,Majdi Hsairi,Olfa Chakroun-Walha,Chokri Ben Hamida,Hedi Chelly,Khaiereddine Ben Mahfoudh,Ab 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.1
Background: Africa, like the rest of the world, has been impacted by the coronavirus disease 2019 (COVID-19) pandemic. However, only a few studies covering this subject in Africa have been published. Methods: We conducted a retrospective study of critically ill adult COVID-19 patients—all of whom had a confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection—admitted to the intensive care unit (ICU) of Habib Bourguiba University Hospital (Sfax, Tunisia). Results: A total of 96 patients were admitted into our ICU for respiratory distress due to COVID-19 infection. Mean age was 62.4±12.8 years and median age was 64 years. Mean PaO2/FiO2 ratio was 105±60 and ≤300 in all cases but one. Oxygen support was required for all patients (100%) and invasive mechanical ventilation for 38 (40%). Prone positioning was applied in 37 patients (38.5%). Within the study period, 47 of the 96 patients died (49%). Multivariate analysis showed that the factors associated with poor outcome were the development of acute renal failure (odds ratio [OR], 6.7), the use of mechanical ventilation (OR, 5.8), and serum cholinesterase (SChE) activity lower than 5,000 UI/L (OR, 5.9). Conclusions: In this retrospective cohort study of critically ill patients admitted to the ICU in Sfax, Tunisia, for acute respiratory failure following COVID-19 infection, the mortality rate was high. The development of acute renal failure, the use of mechanical ventilation, and SChE activity lower than 5000 UI/L were associated with a poor outcome.
Robust-flatness Controller Design for a Differentially Driven Wheeled Mobile Robot
Mabrouk Boubezoula,Abdelouhab Hassam,Oussama Boutalbi 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4
This paper addresses the problem of robust motion control of a Differentially Driven Wheeled Mobile Robot (DWMR). Using the fact that DWMRs are differentially flat systems, the motion control design is relatively simplified by defining the desired motions of the robot in the flat output space of the system. The accurate and the robust trajectories tracking are provided firstly, by imposing the sliding manifold from the flat output space of the system. Secondly, an adaptive gain discontinuous control law -adaptive sliding mode controller- is introduced to drive to zero in finite time such sliding manifold, despite model uncertainties and external disturbances. The system stability is proven using the Lyapunov theory. Compared with classical Feedback control algorithms and using the laboratory test prototype, Pioneer 3DX, simulation and practical tests are presented to illustrate the performances of the proposed approach in the presence of unknown external disturbances.
Impact of prone position on outcomes of COVID-19 patients with spontaneous breathing
Mabrouk Bahloul,Sana Kharrat,Malek Hafdhi,Anis Maalla,Olfa Turki,Kamilia Chtara,Rania Ammar,Basma Suissi,Chokri Ben Hamida,Hedi Chelly,Khaiereddine Ben Mahfoudh,Mounir Bouaziz 대한중환자의학회 2021 Acute and Critical Care Vol.36 No.3
Background: In this study, we explored whether early application of the prone position (PP) can improve severe hypoxemia and respiratory failure in coronavirus disease 2019 (COVID-19) patients with spontaneous breathing. Methods: This is a prospective observational study of severe, critically ill adult COVID-19 patients admitted to the intensive care unit. All vital parameters were recorded in real time for all patients. Moreover, the results of chest computed tomography (CT), when available, were analyzed. Results: PP was applied in 21 patients who were breathing spontaneously. The application of PP was associated with a significant increase in oxygen saturation measured by pulse oximetry (SpO2) from 82%±12% to 96%±3% (P<0.001) 1 hour later. Moreover, PP was associated with a significant reduction in respiratory rate from 31±10 to 21±4 breaths/min (P<0.001). Furthermore, the number of patients who exhibited signs of respiratory distress after PP was reduced from 10 (47%) to 3 (14%) (P=0.04). Early PP application also led to a clear improvement on CT imaging. It was not, however, associated with a reduction in mortality rate or in the use of invasive mechanical ventilation (P>0.05 for both). Conclusions: Our study confirmed that the early application of PP can improve hypoxemia and tachypnea in COVID-19 patients with spontaneous breathing. Randomized controlled trials are needed to confirm the beneficial effects of PP in COVID-19 patients with spontaneous breathing.
Mabrouk Ben Brahim,Hafedh Belhadj Ammar,Ridha Abdelhédi,Youssef Samet 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9
The removal of pesticides from water is a major environmental concern. This study investigates the electrochemical removal of the insecticide imidacloprid (IMD) from aqueous solutions on a boron-doped diamond (BDD) and Ta/PbO2 anodes under galvanostatic electrolysis. The influence of operating parameters, such as applied current density (50-100 mA cm−2), initial chemical oxygen demand COD (0) (281-953mg L−1), temperature (25-65 oC) and pH (3.0-10.0) on COD and instantaneous current efficiency (ICE), was studied using the BDD electrode. The degradation efficiency of IMD increased by increasing current density and temperature, but noticeably decreased by the increase of initial pH value and initial concentration of IMD. The COD decay follows a pseudo-first-order kinetic, and the process was under mass transport control. COD removal reaches 90% when using an apparent current density of 100mA cm−2, initial COD of 953mg L−1, pH of 3.0 and at 25 oC after 4.5 h electrolysis time. Compared with Ta/PbO2, BDD anode has shown better performance and rapidity in the COD removal using the same electrolysis device.
MAPPING PRESERVING NUMERICAL RANGE OF OPERATOR PRODUCTS ON C<sup>*</sup>-ALGEBRAS
MABROUK, MOHAMED Korean Mathematical Society 2015 대한수학회보 Vol.52 No.6
Let $\mathcal{A}$ and $\mathcal{B}$ be two unital $C^*$-algebras. Denote by W(a) the numerical range of an element $a{\in}\mathcal{A}$. We show that the condition W(ax) = W(bx), ${\forall}x{\in}\mathcal{A}$ implies that a = b. Using this, among other results, it is proved that if ${\phi}$ : $\mathcal{A}{\rightarrow}\mathcal{B}$ is a surjective map such that $W({\phi}(a){\phi}(b){\phi}(c))=W(abc)$ for all a, b and $c{\in}\mathcal{A}$, then ${\phi}(1){\in}Z(B)$ and the map ${\psi}={\phi}(1)^2{\phi}$ is multiplicative.