Influence of an Axial-Electromagnetic Field Treatment Device with a Solenoid Structure on Crystallization Fouling on the Tube Side of a Shell-and-Tube Heat Exchanger.

In this study, the influence of an axial-electromagnetic field treatment device (AEFTD) with a solenoid structure using different electromagnetic frequencies on calcium carbonate (CaCO3) crystallization fouling on the tube side of a shell-and-tube heat exchanger was investigated. The experimental results indicated that the application of the AEFTD could effectively reduce fouling resistance and decelerate the growth rate of CaCO3 fouling. The opposite trend between fouling resistance and the outlet temperature of an experimental fluid indicated that the application of the AEFTD could enhance heat transfer. Meanwhile, the crystal morphologies of the fouling samples were analyzed by means of scanning electron microscopy (SEM). The axial-electromagnetic field favored the formation of vaterite as opposed to calcite. Non-adhesive vaterite did not easily aggregate into clusters and was suspended in bulk to form muddy fouling that could be carried away by turbulent flow. Furthermore, the anti-fouling mechanism of the axial-electromagnetic field is discussed in detail. The anti-fouling effect of the AEFTD on CaCO3 fouling exhibited extreme characteristics in this study. Therefore, the effectiveness of the AEFTD is contingent upon the selection of the electromagnetic parameters.

Volume-Targeted Versus Pressure-Limited Noninvasive Ventilation in Subjects With Acute Hypercapnic Respiratory Failure: A Multicenter Randomized Controlled Trial.

BACKGROUND: Volume-targeted noninvasive ventilation (VT-NIV), a hybrid mode that delivers a preset target tidal volume (VT) through the automated adjustment of pressure support, could guarantee a relatively constant target VT over pressure-limited noninvasive ventilation (PL-NIV) with fixed-level pressure support. Whether VT-NIV is more effective in improving ventilatory status in subjects with acute hypercapnic respiratory failure (AHRF) remains unclear. Our aim was to verify whether, in comparison with PL-NIV, VT-NIV would be more effective in correcting hypercapnia, hence reducing the need for intubation and improving survival in subjects with AHRF. METHODS: We performed a prospective randomized controlled trial in the general respiratory wards of 8 university-affiliated hospitals in China over a 12-month period. Subjects with AHRF, defined as arterial pH <7.35 and ≥7.25 and PaCO2 >45 mm Hg, were randomly assigned to undergo PL-NIV or VT-NIV. The primary end point was the decrement of PaCO2 from baseline to 6 h after randomization. Secondary end points included the decrement of PaCO2 from baseline to 2 h after randomization as well as outcomes of subjects (eg, need for intubation, in-hospital mortality). RESULTS: A total of 58 subjects were assigned to PL-NIV (29 subjects) or VT-NIV (29 subjects) and included in the analyses. The decrement of PaCO2 from baseline to 6 h after randomization was not statistically different between the PL-NIV group and the VT-NIV group (9.3 ± 12.6 mm Hg vs 11.7 ± 12.9 mm Hg, P = .48). There were no differences between the PL-NIV group and the VT-NIV group in the decrement of PaCO2 from baseline to 2 h after randomization (6.4 ± 12.7 mm Hg vs 5.0 ± 15.8 mm Hg, P = .71) as well as in the need for intubation (17.2% vs 10.3%, P = .70), and in-hospital mortality (10.3% vs 6.9%, P > .99). CONCLUSIONS: Regardless of whether a VT- or PL-NIV strategy is employed, it is possible to provide similar support to subjects with AHRF. (ClinicalTrials.gov registration NCT02538263.).

[Clinical analysis of thoracoscopy of 30 coalworker's pneumoconiosiswith pleural effusion cases].

OBJECTIVE: To investigate the diagnostic value of thoracoscopy on idiopathic coalworker's pneumoconiosis with pleural effusion in general medicine. METHOD: Routine (general medicine) thoracoscopyof patients suffering from iIdiopathiccoalworker's pneumoconiosis with pleural effusion, pathological examination of lesions obtained (direct vision). RESULT: Pathological examination revealed grayish-white miliary nodules with multiple protruding nodules, irregular focal pleura thickening, pulmonary congestion, edema, fibrous adhesion. Thorascopy produced a diagnostic rate of 93.3%. Confirmed cases includes 13 cases of tuberculous pleurisy, 11 cases of malignant pleural effusion, 4 cases of cardiac insufficiency with pleural effusion and 2 cases of idiopathic pleural effusion, with no serious complications. CONCLUSION: Thoracoscopy of idiopathic coalworker's pneumoconiosis with pleural effusion is a safe, accurate diagnostic methodin general medicine, and could benefit the establishment of a treatment method quickly, visual observation of the lesions of patients suffering from coalworker's pneumoconiosis with pleural effusion using thoracoscopy, and at the same time offer preliminary investigationof the correlation between the intensity and compactibilityof coal macule distribution and clinical stages of coalworker's Pneumoconiosis.

[Analysis of pathogen isolated from lower respiratory tract in coalminer's pneumoconiosis patients complicated with infection].

OBJECTIVE: To investigate the composition and resistance of main pathogens isolated form Lower respiratory tract in coalminer's pneumoconiosis patients complicated with infection to provide the basis for clinical treatment. METHOD: Coalminer's pneumoconiosis patients complicated with infection during 2009 to 2010 were divided into mechanical ventilation group and non mechanical ventilation group. Specimens were obtained from lower respiratory tract by fibrobronchoscopy with protected specimen brush in patients of both groups to perform isolation, culture, identification and susceptibility test of pathogen. RESULT: Total 111 patients were enrolled, 36 of them in mechanical ventilation group and 75 patients in non mechanical ventilation group. The pathogenic bacteria detection rate of patients in mechanical ventilation group was significantly higher than that of patients in non mechanical ventilation group (88.9% vs. 46.7%, P < 0.01). In non mechanical ventilation group, Mycobacterium tuberculosis was detected in 3 patients, and 27 strains of G- bacilli, 3 strains of G+ coccus, and 2 strains of fungus; and 26 strains of G- bacilli, 3 strains of G+ coccus, and 3 strains of fungus were detected in mechanical ventilation group. There was no significant difference in term of strains between the two groups (P > 0.05). Rate of resistance to main antibiotics of patients in mechanical ventilation group was higher than that of patients in non mechanical ventilation group. CONCLUSION: Resistance of pathogenic bacteria isolated from lower respiratory tract was severe in coalminer's pneumoconiosis patients complicated with infection, which was higher in patients treated with mechanical ventilation than patients without mechanical ventilation. Mycobacterium tuberculosis and fungal infection and increasing resistance prompted that clinicians must attach importance to rational drug use and keep to monitoring bacterial resistance.