Robust H∞ output feedback design for networked control systems with partially known delay probabilities

This article develops a predictive robust H_∞ static output feedback control approach for networked control systems where random network-induced delays in both forward and feedback communication channels are modeled as two mutually uncorrelated Markov chains. By making use of the system augmentation method, the closed-loop system is formulated as a singular Markovian jump system with two modes, wherein the transition probability matrices of the underlying Markov chains are considered to be partially accessible. Necessary and sufficient conditions for the stochastic admissibility and robust H_∞ performance of the closed-loop system are given under the assumption of partially known transition probability matrices. A linear matrix inequality condition is proposed to determine the two-mode-dependent static output feedback controller gains to compensate for the random network-induced delays efficiently and provide the desired control performance. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed approach.     

Esophagus adenocarcinoma in a young patient with celiac disease; Is celiac disease a predisposing factor for esophagus adenocarcinoma as well as squamous cell carcinoma?

We report a 36-year-old female with longstanding oily diarrhea and new-onset dysphagia that was diagnosed as celiac disease and esophagus adenocarcinoma. Celiac is a multisystemic autoimmune disease associated with a longstanding inflammatory process, especially in the gastrointestinal tract. This chronic inflammation may lead to a modest increase in neoplasia risk. There is a modest increased risk of malignancy in celiac disease, particularly adenocarcinoma and T-cell lymphoma of the small intestine and squamous cell carcinoma (SCC) of the esophagus, mouth, and pharynx. Although there is an association between SCC of the esophagus and celiac disease, there are no reports in the English literature about a relationship between celiac disease and esophageal adenocarcinoma. This case shows that as well as SCC, adenocarcinoma of the esophagus may also occur in patients with longstanding celiac disease.     

Controlled release from a mechanically-stimulated thermosensitive self-heating composite hydrogel

Temperature has been extensively explored as a trigger to control the delivery of a payload from environment-sensitive polymers. The need for an external heat source only allows limited spatiotemporal control over the delivery process. We propose a new approach by using the dissipative properties of a hydrogel matrix as an internal heat source when the material is mechanically loaded. The system is comprised of a highly dissipative hydrogel matrix and thermo-sensitive nanoparticles that shrink upon an increase in temperature. Exposing the hydrogel to a cyclic mechanical loading for a period of 5 min leads to an increase of temperature of the nanoparticles. The concomitant decrease in the volume of the nanoparticles increases the permeability of the hydrogel network facilitating the release of its payload. As a proof-of-concept, we showed that the payload of the hydrogel is released after 5–8 min following the initiation of the mechanical loading. This delivery method would be particularly suited for the release of growth factor as it has been shown that cell receptor to growth factor is activated 5–20 min following a mechanical loading.     

Clinical and obstetric characteristics of pregnant women with Covid-19: A case series study on 26 patients

ObjectiveTo evaluate the clinical characteristics and outcomes of pregnant women with Covid-19.Materials and methodsThis case series study was performed to investigate demographic, clinical and obstetric characteristics of 26 pregnant women with COVID-19 referring to a university hospital of Kashan during the epidemic of COVID-19 (March to May 2020).ResultsThe mean gestational age of the patients at admission and delivery was 31.8 ± 5.2 and 36.3 ± 3.4 weeks, respectively. The most common symptoms were fever (96.2%) followed by dyspnea and cough (30.8%). The findings of lung CT scan showed abnormalities confirming the pneumonia in 22 patients (84.6%). Cesarean section was performed in 69.2% of the mothers. The most common maternal–fetal outcome was preterm delivery (38%). Two mothers were transferred to the ICU due to deterioration in clinical condition and they underwent mechanical ventilation without any maternal death. The most common neonatal outcomes were prematurity (38%) and low birth weight (34.6%). No cases of confirmed COVID-19 were observed in the neonates.ConclusionClinical manifestations and laboratory and radiographic findings in pregnant women with COVID-19 are similar to the general population. Common outcomes of pregnancy and delivery in mothers included increased rate of preterm delivery and cesarean section. The most prevalent neonatal outcomes included prematurity and LBW. Careful monitoring of pregnant women with COVID-19 is recommended.     

Alpha heavy-chain disease in Southern Iran

A prospective study of 32 patients with primary upper small intestinal lymphoma in our region revealed 10 cases of alpha heavy-chain disease. Patients were mostly in the second and third decades of life and males predominated. Weight loss, diarrhea, and abdominal pain were the most common complaints and clubbing the most frequent physical findings. Laboratory tests revealed a malabsorption pattern on intestinal x-rays, and malabsorption of xylose, fat, and vitaminB ₁₂ was frequently noted. Dense plasmacytic infiltrate of the lamina propria of small bowel was the most frequent pathologic finding while true neoplasm of the lymphoid system (ie, immunoblastic sarcoma) was encountered in 20% of the cases.