In recent years, various complex systems and real-world phenomena have been shown to include memory and hereditary properties that change with respect to time, space, or other variables. ...Consequently, fractional partial differential equations containing variable-order fractional operators have been extensively resorted for modeling such phenomena accurately. In this paper, we consider the two-dimensional fractional cable equation with the Caputo variable-order fractional derivative in the time direction, which is preferable for describing neuronal dynamics in biological systems. A point-wise scheme, namely, the Crank–Nicolson finite difference method, along with a group-wise scheme referred to as the explicit decoupled group method are proposed to solve the problem under consideration. The stability and convergence analyses of the numerical schemes are provided with complete details. To demonstrate the validity of the proposed methods, numerical simulations with results represented in tabular and graphical forms are given. A quantitative analysis based on the CPU timing, iteration counting, and maximum absolute error indicates that the explicit decoupled group method is more efficient than the Crank–Nicolson finite difference scheme for solving the variable-order fractional equation.
In recent years, the application of variable-order (VO) fractional differential equations for describing complex physical phenomena ranging from biology, hydrology, mechanics and viscoelasticity to ...fluid dynamics has become one of the most hot topics in the context of scientific modeling. An interesting aspect of VO operators is their capability to address the behavior of scientific and engineering systems with time and spatially varying properties. The VO fractional diffusion equation is a fundamental model that allows transitions among sub-diffusive, diffusive and super-diffusive behaviors without altering the underlying governing equations. In this paper, we considered the two-dimensional fractional diffusion equation with the Caputo time VO derivative, which is essential for describing anomalous diffusion in real-world complex systems. A new Crank-Nicolson (C-N) difference scheme and an efficient explicit decoupled group (EDG) method were proposed to solve the problem under consideration. The proposed EDG method is based on a skewed difference scheme in conjunction with a grouping procedure of the solution grid points. Special attention was devoted to investigating the stability and convergence of the proposed methods. Three numerical examples with known exact analytical solutions were provided to illustrate our considerations. The proposed methods were shown to be stable and convergent theoretically as well as numerically. In addition, a comparative study was done between the EDG method and the C-N difference scheme. It was found that the proposed methods are accurate in simulating the considered problem, while the EDG method is superior to the C-N difference method in terms of Central Processing Unit (CPU) timing, verifying the efficiency of the former method in solving the VO problem.
Transversus abdominis plane block (TAPB) guided by laparoscopy and ultrasound showed promise in enhancing the multimodal analgesic approach following several abdominal procedures. This study aimed to ...compare the efficacy and safety between Laparoscopic (LAP) TAP block (LTAP) and ultrasound-guided TAP block (UTAP) block in patients undergoing LAP bariatric surgery.
This non-inferiority randomized controlled single-blind study was conducted on 120 patients with obesity scheduled for LAP bariatric surgeries. Patients were allocated into two equal groups: LTAP and UTAP, administered with 20 mL of 0.25% bupivacaine on each side.
There was no statistically significant difference in the total morphine consumption, Visual Analogue Scale (VAS) score at all times of measurements, and time to the first rescue analgesia (p > .05) between both groups. The duration of anesthesia and duration of block performance were significantly shorter in the LTAP group than in the UTAP group (p < .001). Both groups had comparable post-operative heart rate, mean arterial pressure, adverse effects, and patient satisfaction.
In LAP bariatric surgery, the analgesic effect of LTAP is non-inferior to UTAP, as evidenced by comparable time to first rescue analgesia and total morphine consumption with similar safety blocking through the low incidence of post-operative complications and patient satisfaction.
The study was registered in Pan African Clinical Trials Registry (PACTR) (ID: PACTR202206871825386) on June 29, 2022.
Statins are known to affect brain function in a manner not related to their dyslipidemic effects. The purpose of the present study was to assess the behavioral response of a chick model (7-14 days ...old) after single treatments with the statins atorvastatin, fluvastatin or simvastatin at 100 mg/kg, orally, to a pharmacological challenge with an anesthetic regimen of xylazine (5 mg/kg)-ketamine (20 mg/kg), intramuscularly, and a toxicological challenge with the reversible cholinesterase inhibiting insecticide carbaryl (250 mg/kg, orally). Only simvastatin significantly reduced the duration of xylazine-ketamine anesthesia by 47%. Carbaryl at 250 mg/kg, orally induced signs of cholinergic poisoning (57.1 - 100%) in chicks within 3.14 min, and 57.1% death occurred within 85 min. Toxicological challenge of statin-treated chicks with carbaryl also induced signs of cholinergic poisoning, but with varying percentages of reductions compared to the control (carbaryl) group. The reductions in 4 h carbaryl-induced lethality in chicks pre-treated with atorvastatin, fluvastatin and simvastatin were 43, 57 and 29%, respectively, below that of the control value. Correspondingly, their toxicity scores decreased by 18, 18 and 11%, respectively. These data suggest that statins might modulate the functional status of the brain in a manner that affects the impact of centrally acting drugs or toxicants, and hence the behavioral outcomes in chicks. Further studies are warranted on the behavioral effects of statins after prolonged therapy.
The real behaviour of connections in the steel buildings is often underestimated by designers at the structural analysis and design stages, despite their influences on the structural performance, ...deflection limits and a possibility of achieving a reduction in the material weights, which can significantly reduce the overall cost and amount of energy embodied. This paper, therefore, described systematic and simplified procedures to conduct a first-order elastic structural analysis of the semi-rigid steel portal frames in order to implement a design optimization using a Generalized Reduced Gradient (GRG) algorithm within Solver Add-in tool in Microsoft Excel. The written program used the robustness and efficiency of the Finite Element (FE) method with the versatility of a spreadsheet format in Excel. To simulate the semi-rigid response of the connections, the mathematical representation through End-Fixity Factor and the Modified Stiffness Matrix were used to incorporate such behaviour into structural analysis packages. To validate the written program, a computer-based analysis was conducted using Prokon® software and comparing analysis results with those obtained from the Excel spreadsheet. It demonstrates that Excel's results were perfectly accurate. Consequently, the procedure of establishing spreadsheets as a finite element analysis software for a certain form of frames demonstrates its validity.
In this article, we developed a new higher-order implicit finite difference iterative scheme (FDIS) for the solution of the two dimension (2-D) time fractional Cable equation (FCE). In the new ...proposed FDIS, the time fractional and space derivatives are discretized using the Caputo fractional derivative and fourth-order implicit scheme, respectively. Moreover, the proposed scheme theoretical analysis (convergence and stability) is also discussed using the Fourier analysis method. Finally, some numerical test problems are presented to show the effectiveness of the proposed method.
Background
Magnetic resonance imaging (MRI) is the best diagnostic tool for suspected diabetic foot osteomyelitis (DFO); adding T1-based Dixon to MR technique can identify the bone marrow edema-like ...signal observed in neuropathic joints and differentiate it from that observed in DFO. The aim of this study was to assess the diagnostic efficacy of chemical shift imaging (T1 in-phase and out-of-phase) and related Dixon sequence in differentiation between infectious edema-like signal found in osteomyelitis and bland edema signals observed in osteomyelitis mimickers (as neuropathic arthropathy). The study was conducted on 50 patients who were referred by surgical outpatient clinics between January 2020 and January 2022; they underwent MRI of the foot including T1-Dixon sequence.
Results
There were variable bone and joint affection, and the most common location of bony affection in the study was the hind-foot. Forty-four out of fifty patients had bone marrow edema-like signals. Thirty-seven patients (74%) were diagnosed with osteomyelitis, whereas seven (14%) patients were diagnosed with non-infective/bland bone marrow edema signals which were related to Charcot arthropathy and/or nearby infection. Both visual and quantitative assessments of chemical shift imaging showed high sensitivity and specificity in diagnosis of DFO. The optimal cut-off point of signal intensity ratio for diagnosis of DFO was 1.005 with high sensitivity and specificity.
Conclusions
Chemical shift imaging and related Dixon sequence were reliable methods in diabetic foot evaluation; they could help differentiate infectious edema-like changes of osteomyelitis from and bland edema of osteomyelitis mimickers with high sensitivity and specificity especially on using quantitative analysis of their signal abnormality.
Background and objective The hypolipidemic statins have been associated with various side effects, and in some cases, adverse reactions in humans and experimental animals, such as myotoxicity, ...neurobehavioral toxicity, as well as liver and kidney injuries. The purpose of the present study was to examine the possibility of the induction of oxidative stress in the brain and plasma of mice dosed with single or repetitive doses of three statins (atorvastatin, simvastatin, and rosuvastatin). Methods Male Swiss-origin mice were dosed orally with single doses of each of the three statins at 500 or 1000 mg/kg of body weight. Other groups of mice were dosed orally with repeated daily doses of each of the statins at 200 mg/kg of body weight/day for 14 or 28 consecutive days. These doses of statins were chosen to not produce overt toxicity in mice within the time frame allocated for each experiment. Brain and plasma glutathione (GSH) and malondialdehyde (MDA) levels, as well as liver enzymes activities alanine transaminase (ALT) and aspartate transaminase (AST), were determined using commercial kits. Results Single-dose treatments of the mice with the statins at either 500 or 1000 mg/kg significantly and dose-dependently (p < 0.05) reduced the GSH level in the plasma and the whole brain when compared with respective control values. Atorvastatin was the least effective statin, as only the high dose achieved a significant reduction in brain GSH level in comparison with the respective control value. Repetitive administration of the three statins at 200 mg/kg of body weight/day for 14 or 28 consecutive days significantly and time-dependently reduced plasma and brain GSH levels in comparison with respective control values. The oxidative stress biomarker MDA level significantly increased in the plasma and brain of mice following single or repetitive treatments with the three statins, and the most effective one was rosuvastatin. In association with these changes, activities of the liver enzymes ALT and AST were also increased in the plasma with single and repetitive statin treatments, and the most effective one was rosuvastatin. Conclusion The data suggest an association of high doses of three statins (atorvastatin, simvastatin, and rosuvastatin) with the induction of oxidative stress manifested as GSH reduction and MDA elevation as adverse effects in the brain and plasma of mice, which suffered from the additional burden of liver injury. These effects could be the basis of an in-depth exploration of statin adverse effects in experimental animals and to find an animal model, probably the mice, for the induction of adverse effects of statins that target the brain, as well as to shed light on potential statin intolerance outcomes following single-dose treatments in this species.
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