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We analyze a finite volume scheme for a nonlinear reaction-diffusion system applied to image processing. First, we demonstrate the existence of a solution to the finite volume scheme. Then, based on the derivation of a series of a priori estimates and the use of Kolmogorov’s compactness criterion, we prove that the solution to the finite volume scheme converges to the weak solution. In the numerical experiments, we show the effectiveness of the proposed model with respect to the modified (in the sense of Catté, Lions, Morel and Coll) Perona-Malik nonlinear image selective smoothing equation in terms of preserving small details, texture, and fine structures.

Purpose: The purpose of this study was to investigate the applicability of the adsorption process of a persistent organophosphorus pesticide (malathion) from aqueous solutions by using titanium dioxide- polypropylene nanocomposite (Nano-PP/TiO 2 )., Methods: The structure of Nano-PP/TiO 2 was specified by field emission scanning electron microscopes (FE-SEM), fourier-transform infrared spectroscopy (FTIR), brunauer-emmett-teller (BET), and transmission electron microscope (TEM) technologies. Response surface methodology (RSM) was applied to optimize the adsorption of malathion onto Nano-PP/TiO 2 and investigates the effects of various experimental parameters including contact time (5-60 min), adsorbent dose (0.5-4 g/l) and initial malathion concentration (5-20000 mg/l). Extraction and analysis of malathion were performed by dispersive liquid-liquid microextraction (DLLME) coupled with a gas chromatography, coupled with flame ionization detector (GC/FID)., Results: The isotherms obtained for Nano-PP/TiO 2 revealed that it was a mesoporous material with a total pore volume of 2.06 cm 3 /g, average pore diameters of 2.48 nm and a surface area of 51.52 m 2 /g. The obtained results showed that the Langmuir type 2 was the best-fitted model for delegating the equilibrium data of isotherm studies with adsorption capacity of 7.43 mg/g, and pseudo-second-order type 1 for kinetic model. The optimized conditions to achieve the maximum removal (96%) were at a malathion concentration of 7.13 mg/L, contact time of 52 min and adsorbent dose of 0.5 g/L., Conclusion: Due to its efficient and appropriate function in adsorbing malathion from aqueous solutions, it was revealed that Nano-PP/TiO 2 can be used as an effective adsorbent as well as in further studies., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s), under exclusive licence to Tehran University of Medical Sciences 2022, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Rationale: As there are no evidence based guidelines for the diagnosis and/or management of pulmonary nodules in children, there is an over reliance on the adult based algorithms when dealing with pulmonary nodules in children. We present our experience of pediatric patients evaluated for incidentally found pulmonary nodules., Methods: Retrospective chart review of patients diagnosed with a pulmonary nodule and evaluated at Goryeb Children's Hospital between January 2000 and December 2012., Primary Outcome: change in the size of the pulmonary nodule between the initial and follow-up imaging., Results: Thirty six patients with pulmonary nodule (21 male/15 female; Median [range] age 15 [5-20] years.) were included in the study. Chest CT was obtained for respiratory symptoms and/or abnormal chest radiograph in 19 (52%). Nine pulmonary nodules (25%) were identified on abdominal CT obtained for abdominal symptoms. A total of 46 nodules were identified in 36 patients. Nine of the pulmonary nodules (9 patients) were ≤4 mm in size, 37 of the pulmonary nodules (27 patients) were >4 mm in size. Twenty-two of the 27 (81%) patients with nodule size >4 mm had follow-up CT: 14 nodules (54%) remained unchanged in size, 5 nodules (19%) decreased in size, and 7 nodules (27%) were not detected., Conclusion: Our review of 36 patients with pulmonary nodules shows no obvious growth of the nodules over the study period, suggesting low risk of malignancy. Routine follow-up chest computer tomography using ACCP/Fleischner Society guidelines may not apply in children without known malignancy., (© 2014 Wiley Periodicals, Inc.)

Background: Tracheoesophageal fistula (TEF) is the most common congenital tracheal abnormality, frequently associated with esophageal atresia. Respiratory symptoms are associated with all types of TEF, even after surgical repair of the fistula. Gastroesophageal reflux (GER) with aspiration of gastric contents, structural instability of the airways (tracheomalacia), abnormal respiratory epithelium, abnormal esophageal motility, recurrent TEF, and esophageal stenosis contribute to postsurgical complications., Methods: We review 7 patients between 4 and 14 years of age with a history of TEF repair and persistent or worsening respiratory symptoms despite conventional airway clearance techniques and treatment of GER., Results: Bronchoscopic evaluation in all 7 patients revealed tracheomalacia and a diverticulum on the posterior wall of the trachea at the fistula repair site., Conclusion: We hypothesize that the diverticula impaired airway clearance and contributed to persistent respiratory symptoms. Possible mechanisms for the diverticulum contributing to poor airway clearance include facilitating the pooling of secretions and acting as a "barrier" to the lower airway clearance mechanism. The diagnosis of a diverticulum should be considered early in patients with persistent respiratory symptoms after management of GER and tracheomalacia. Early obliteration of tracheal diverticula might improve respiratory status in some patients.

Introduction: Inhaled short-acting bronchodilators are recommended for the quick relief of bronchospasm symptoms in children including those less than five years of age. However, limited safety data is available in this young population., Methods: Safety data were analyzed from a randomized, double-blind, parallel group, placebo-controlled multicenter, study evaluating albuterol HFA 90microg or 180microg versus placebo three times a day for 4 weeks using a valved holding chamber, Aerochamber Plus and facemask in children birth

Between July 1985 and March 1992, 20 children received either heart-lung (11), double lung (8), or single lung (1) transplants at our center. Since 1988, flexible fiberoptic bronchoscopy with bronchoalveolar lavage and transbronchial biopsy have been carried out to monitor for rejection or infection in these patients. As of March 31, 1992, we have performed a total of 112 transbronchial biopsies in our patients, who ranged from 6.8 to 18 years of age and 19.3 to 67.3 kg in weight. All but two of these procedures were carried out using conscious sedation and a transnasal approach. Four to seven biopsy samples were obtained at each procedure. One patient had hemorrhage (< 100 ml) and no patient had pneumothorax as a complication. Of the biopsy samples, 72.4 percent had a surface area of greater than 2 mm2, and 89.5 percent of the biopsy samples were deemed adequate for pathologic interpretation. We believe that for the majority of pediatric lung or heart-lung recipients, flexible bronchoscopy and transbronchial biopsy using conscious sedation and a transnasal approach is safe and permits the recovery of adequate tissue for pathologic evaluation. The avoidance of general anesthesia, endotracheal intubation, and mechanical ventilation at the time of bronchoscopy and transbronchial biopsy probably decreases the likelihood of pneumothorax as a complication of the procedure.

Stenosis of the tracheobronchial tree can be a life-threatening problem. Management options for symptomatic stenosis include serial dilation, cryotherapy, laser resection, and open surgical correction. Recently, balloon angioplasty catheters have been used to dilate stenotic airway segments. The experience in infants is limited and has for the most part utilized guide wires and fluoroscopy for balloon placement. We present two infants with symptomatic bronchial stenosis who underwent endoscopic angioplasty balloon catheter dilation. Operative technique involved catheter placement under direct vision with a rigid bronchoscope. Catheters (6F) with 8-mm-diameter balloons were used. Balloon expansion was controlled with a hand-held manometer. Both infants demonstrated significant lumen size improvement intraoperatively and marked clinical improvement postoperatively, substantiated by endoscopy and radiographs. One infant has required one repeat dilation and has subsequently been asymptomatic. The other infant has had no further respiratory problems. Our technique, using a rigid bronchoscope with direct visualization of catheter placement, obviates the need for guide wires and C-arm fluoroscopy as previously described. Endoscopic placement enables direct visualization of balloon position, and fine adjustments are possible if further dilation is necessary. Rigid bronchoscopic balloon catheter dilation can be a successful technique for bronchial stenosis and should be considered prior to attempting more invasive surgical correction.

Objective: To differentiate the insulin-dependent glucose intolerance associated with cystic fibrosis from type I diabetes mellitus in patients with cystic fibrosis., Design: Patient report., Setting: Tertiary care referral center., Participant: An 11-year-old boy with cystic fibrosis who developed diabetic ketoacidosis. MEASUREMENT/MAIN RESULT: Biochemical, immunologic, and molecular techniques were used to support the sporadic association of type I diabetes mellitus in a patient with cystic fibrosis. Cystic fibrosis was confirmed by sweat test and further supported by the demonstration of a heterozygous deletion of the F508 locus. Evidence for the diagnosis of type I diabetes mellitus was developed from the clinical presentation of diabetic ketoacidosis with hyperglycemia, ketonemia, and ketonuria. Immunologic evidence included the demonstration of anti-insulin antibodies. The demonstration of homozygous absence of aspartic acid at position 57 of the HLA DQ-beta chain placed this child at high risk of type I diabetes mellitus., Conclusion: The clinical presentation and the presence of immunologic and genetic markers characteristic of type I diabetes mellitus supports the concordance of cystic fibrosis and type I diabetes mellitus in this patient.

Metallothioneins (MT) are low molecular weight proteins that are important in providing protection against heavy metals such as cadmium. Other precise physiologic roles for this family of proteins are less clear, but fetal hepatic cell proliferation and differentiation may be regulated through changes in MT levels and attendant MT-mediated regulation of zinc levels. The role of MT in other developing tissue, most notably lung, is far less clear. Although expression of MT has been reported to be extremely low in early postnatal and mature lung, we hypothesized that MT has a more ubiquitous role in organ development and that pulmonary MT levels may be elevated during periods of rapid lung growth. Thus, we studied expression of MT in late-gestation fetal lambs. Sheep are particularly useful because alveolarization of lung parenchyma occurs before birth (by d 120 of a normal 147-d gestation). Immunoreactive MT was localized to bronchial epithelium of fetal, newborn, and mature sheep. The intensity of staining was greatest in the 130-d gestational age (saccular) lung, where positive reaction product was noted in the cytoplasm and nucleus of alveolar epithelial and interstitial cells. We next evaluated MT expression in developing lung tissue using Northern blot analysis and 32P-cDNA probes against the 3'-untranslated regions of mRNA encoding each of four known functional sheep MT (sMT) isoforms. Expression of sMT-II, sMT-Ia, and sMT-Ib was restricted to the saccular stage (120-132 d gestational age), and sMT-Ic mRNA was not detected in pulmonary samples from any stage of development.(ABSTRACT TRUNCATED AT 250 WORDS)

Five young children with cystic fibrosis and abdominal pain were found to have pancreatitis. Diagnosis was delayed in four patients because of the belief that pancreatitis occurs only in older patients with cystic fibrosis. In one patient pancreatitis was diagnosed before cystic fibrosis and diagnosis of cystic fibrosis was delayed. Pancreatitis should be considered as a possible cause of abdominal pain in pancreatic-sufficient children with cystic fibrosis and cystic fibrosis should be considered as a possible cause of pancreatitis, even in the young child.

The capacity of bovine tracheal epithelial cells to convert arachidonic acid to oxygenation products with potential biologic activity was studied in homogeneous preparations of isolated cells. Purified epithelial cell suspensions were incubated with radiolabeled arachidonic acid, and oxygenated metabolites were identified using high-pressure liquid chromatography and gas chromatography-mass spectrometry. The cells released predominantly two products during incubation with 0.3 to 150 microM arachidonic acid for 1 to 60 min at 37 degrees C: prostaglandin E2 (PGE2) and 12-hydroxyeicosatetraenoic acid (12-HETE). Concentration-response curves for the two products yielded half-maximal effects at 2 and 45 microM arachidonic acid, respectively. Stereochemical analysis by chiral-phase high-pressure liquid chromatography demonstrated that the epithelial 12-HETE consisted exclusively of the 12(S) isomer, providing supporting evidence that it was derived from an arachidonate 12-lipoxygenase. Epithelial cells prelabeled with arachidonic acid and incubated with 5 microM A23187 to stimulate endogenous arachidonic acid metabolism also released two predominant products with the chromatographic properties of PGE2 and 12-HETE. The findings demonstrate that bovine tracheal epithelial cells express both a cyclooxygenase:PGE isomerase and a 12-lipoxygenase pathway and therefore implicate this pathway as a new source of epithelial cell mediators.