Design of a fractional-order atmospheric model via a class of ACT-like chaotic system and its sliding mode chaos control.

Investigation of the dynamical behavior related to environmental phenomena has received much attention across a variety of scientific domains. One such phenomenon is global warming. The main causes of global warming, which has detrimental effects on our ecosystem, are mainly excess greenhouse gases and temperature. Looking at the significance of this climatic event, in this study, we have connected the ACT-like model to three climatic components, namely, permafrost thaw, temperature, and greenhouse gases in the form of a Caputo fractional differential equation, and analyzed their dynamics. The theoretical aspects, such as the existence and uniqueness of the obtained solution, are examined. We have derived two different sliding mode controllers to control chaos in this fractional-order system. The influences of these controllers are analyzed in the presence of uncertainties and external disturbances. In this process, we have obtained a new controlled system of equations without and with uncertainties and external disturbances. Global stability of these new systems is also established. All the aspects are examined for commensurate and non-commensurate fractional-order derivatives. To establish that the system is chaotic, we have taken the assistance of the Lyapunov exponent and the bifurcation diagram with respect to the fractional derivative. To perform numerical simulation, we have identified certain values of the parameters where the system exhibits chaotic behavior. Then, the theoretical claims about the influence of the controller on the system are established with the help of numerical simulations.

Navigating climate complexity and its control via hyperchaotic dynamics in a 4D Caputo fractional model.

This interdisciplinary study critically analyzes current research, establishing a profound connection between sea water, sea ice, sea temperature, and surface temperature through a 4D hyperchaotic Caputo fractional differential equation. Emphasizing the collective impact on climate, focusing on challenges from anthropogenic global warming, the study scrutinizes theoretical aspects, including existence and uniqueness. Two sliding mode controllers manage chaos in this 4D fractional system, assessed amid uncertainties and disruptions. The global stability of these controlled systems is also confirmed, considering both commensurate and non-commensurate 4D fractional order. To demonstrate the intricate chaotic motion within the system, we employ the Lyapunov exponent and Poincare sections. Numerical simulations are conducted by using the predictor-corrector method. The effects of surface temperature on chaotic dynamics are discussed. The crucial role of sea ice reflection in climate stability is highlighted in two scenarios. Correlation graphs, comparing model and observational data using the predictor-corrector method, enhance the proposed 4D hyperchaotic model's credibility. Subsequently, numerical simulations validate theoretical assertions about the controllers' influence. These controllers indicate which variable significantly contributes to controlling the chaos.

Primary amyloidosis causing diffuse alveolar hemorrhage.

Diffuse alveolar hemorrhage is a serious complication that has been described in various disease states including several vasculitic syndromes as well as conditions that may resemble vasculitis clinically. In this article, we present a case of 79-year-old man, who was admitted with productive cough, blood-tinged sputum, and a positive atypical antineutrophil cytoplasmic antibody pattern on indirect immunofluorescence microscopy. He subsequently developed frank hemoptysis and respiratory failure. Open lung biopsy demonstrated amyloid deposition within blood vessels. He was treated with 1 g of intravenous methylprednisolone over 3 days with rapid improvement in hemoptysis and hypoxemia. This case report and a review of literature illustrate unusual clinical manifestations of vascular amyloidosis that may be confused with vasculitis. Accurate diagnosis of this condition may improve clinical outcome and spare the patient from unwarranted, potentially harmful treatments.

A prospective open-label study of mycophenolate mofetil for the treatment of diffuse systemic sclerosis.

OBJECTIVE: To evaluate the efficacy and safety of mycophenolate mofetil for the treatment of SSc. METHODS: We recruited 15 patients with dcSSc to take part in an open-label study using mycophenolate mofetil to treat their disease over a 12-month period. The primary outcome measure was the modified Rodnan skin score (mRSS), whereas secondary outcomes included the Medsger severity score, pulmonary function studies, 2D echocardiograms and the Short Form Health Survey (SF)-36 questionnaire. RESULTS: The mRSS significantly improved in those patients who tolerated the medication for >3 months (P < 0.0001), and there was a statistically significant improvement in the Medsger severity scores of the general (P = 0.05), peripheral vascular involvement (P = 0.05) and skin (P = 0.0003) scores. The SF-36 scores improved (P = 0.05) and the pulmonary function studies showed a trend towards improvement, though not of statistical significance. The mean pulmonary artery pressure by 2D echocardiography did not change. CONCLUSIONS: In this prospective open-label study of mycophenolate mofetil for the treatment of dcSSc, we observed significant improvements in skin scores, peripheral vascular involvement and patient-perceived health status. Pulmonary function studies did not worsen as expected, but instead showed a trend towards improvement. Controlled trials are needed to further investigate this trend for improved pulmonary function studies.

The use of mycophenolate mofetil for the treatment of systemic sclerosis.

Mycophenolate mofetil (MMF) is an inosine monophosphate dehydrogenase inhibitor, that inhibits the de novo pathway of guanosine nucleotide synthesis, the proliferative responses of T and B lymphocytes as well as antibody production by B-lymphocytes. It is indicated for the prophylaxis of organ rejection after allogeneic cardiac, hepatic and renal transplants . It has recently also been used with good success in patients with lupus nephritis . Based on these actions, MMF appears to be a novel agent for the treatment of systemic sclerosis, especially during early disease where an inflammatory infiltrate preceeds the development of fibrosis. Disease modification early on during the inflammatory stage of systemic sclerosis may lead to an overall decrease in fibrotic complications both in relation to cutaneous and internal organ involvement.