A Fast Calibration Method for Pneumotachograph with a 3L Syringe.

The pneumotachograph (PNT), a commonly used flowmeter in pulmonary function diagnostic equipment, is the required frequency calibration to maintain high accuracy. Aiming to simplify calibration steps, we developed a fast calibration system with a commercially available 3L syringe to provide a real output flow waveform. The acquisition of the real output flow waveform is based on the reliable measurement of in-cylinder pressure and the real-time detection of plunger speed. To improve the calibration accuracy, the tapping position for measuring in-cylinder pressure was optimized by CFD dynamic-mesh updating technique. The plunger speed was obtained by tracking the handle of the plunger with a smart terminal. Then, the real output flow was corrected using a compensation model equation. The calibration system was verified by the pulmonary waveform generator that the accuracy satisfied the requirements for respiratory flow measurement according to ATS standardization. The experimental results suggest that the developed method promises the fast calibration of PNT.

Synergistic effect of photo-thermal oxidation for a low concentration of HCHO over Bi3+-TiO2/MnFeOx catalysts at ambient temperature.

Formaldehyde (HCHO) has been one of the important air pollutants, and the effective removal of HCHO at ambient temperature has been a big challenge. In this work, the synergistic effect of photo-thermal oxidation with Bi3+-TiO2/MnFeOx for a low concentration of HCHO was investigated. MnFeOx was synthesized by the complexation method (CM) and co-precipitation (CP), and TiO2 with Bi3+ doping supported on MnFeOx was prepared by using the hydrothermal method to obtain a higher oxidation performance. The results demonstrated an excellent oxidation activity of MnFeOx (CM) for HCHO at ambient temperature, attributed to the morphology effect (large surface areas and small crystal sizes), the large absorption of oxygen, and the interaction and oxygen vacancy formed between MnO2 and FeOx. Although Bi3+-TiO2/MnFeOx showed a similar result as MnFeOx at 48 h, the oxidation activities for HCHO were improved prominently under photo-thermal oxidation at 12 h. The improvement was ascribed to the synergistic effect of Bi3+-TiO2 and MnFeOx with surface adsorbed oxygen, and more generated reactive oxygen species on the surface. In particular, 2 wt% Bi3+-TiO2/MnFeOx displayed the highest activity (90.2%) and good stability (5 cycles), and the HCHO average conversion was increased from 46.2 to 58.2% at 12 h. The feasible oxidation mechanism and reaction pathway were also interpreted. This work provides a new insight for the development of photocatalysts supported on transition metal oxides to oxidize HCHO at ambient temperature.

Improved activity and stability for chlorobenzene oxidation over ternary Cu-Mn-O-Ce solid solution supported on cordierite.

A series of CuMnOx/CeO2/cordierite and CuMnCeOx/cordierite catalysts prepared by a complex method with citric acid were investigated for the performance of chlorobenzene (CB) oxidation. The effects of the molar ratio of Mn/Cu, transition metal oxide loading, calcination temperature and time were investigated as the main investigation factor for the performance. Meanwhile, XRD, SEM, BET, H2-TPR, O2-TPD and XPS were conducted to characterize the physicochemical properties of these catalysts. The results demonstrated that CuMnOx/CeO2/cordierite catalysts prepared by step-by-step synthesis with the Cu/Mn molar ratio of 5:2 exhibited a high activity (T90 = 350 °C), owing to the incorporation of CuO and MnOx for forming CuMn2O4 spinel oxide supported on CeO2 surface. More importantly, CuMnCeOx/cordierite catalysts prepared by one-step exhibited the highest oxidation activity (T90 < 300 °C) attributed to the low H2 reduction temperature and desorption energy of surface oxygen, and the formed Cu-Mn-O-Ce solid solution and CeO2 promoted the high dispersion of CuMnOx in the supported catalysts. In addition, the possible oxidation mechanism was described to demonstrate the by-products generation and oxygen transfer of CuMnCeOx catalysts.

A Flexible Ultrasound Array for Local Pulse Wave Velocity Monitoring.

Pulse wave velocity (PWV) measured at a specific artery location is called local PWV, which provides the elastic characteristics of arteries and indicates the degree of arterial stiffness. However, the large and cumbersome ultrasound probes require an appropriate sensor position and pressure maintenance, introducing usability constraints. In this paper, we developed a light (0.5 g) and thin (400 µm) flexible ultrasound array by encapsulating 1-3 composite piezoelectric transducers with a silicone elastomer. It can capture the distension waveforms of four arterial positions with a spacing of 10 mm and calculate the local PWV by multi-point fitting. This is illustrated by in vivo experiments, where the local PWV value of five normal subjects ranged from 3.07 to 4.82 m/s, in agreement with earlier studies. The beat-to-beat coefficient of variation (CV) is 12.0% ± 3.5%, showing high reliability. High reproducibility is shown by the results of two groups of independent measurements of three subjects (the error between the mean values is less than 0.3 m/s). These properties of the developed flexible ultrasound array enable the bandage-like application of local PWV monitoring to skin surfaces.

[Influencing factors on AIDS-related deaths in Guangzhou 1991-2013].

OBJECTIVE: To analyze the influencing factors on AIDS-related deaths among HIV/AIDS patients in Guangzhou, Guangdong province. METHODS: A retrospective cohort was formed, based on available data of HIV/AIDS patients between 1991 and 2013 in Guangzhou, that were gathered from the Chinese AIDS Prevention and Control Information System. Cox proportional hazard model was used to identify the influencing factors for AIDS-related deaths. RESULTS: Data showed that factors as: existence of full-bloom AIDS when HIV infection was diagnosed (HR =2.717, 95%CI: 2.039-3.621) , diagnose of AIDS was made in the hospitals (HR=1.516, 95%CI: 1.159-1.981) , never received no CD(4) count testing (HR=4.866, 95%CI: 3.674-6.444) , no drugs were provided to those who met the criteria for treatment (HR=12.213, 95%CI: 8.467-17.616) , and patients at aged ≥40 years when HIV infection was diagnosed etc., were related to the risk for AIDS deaths. The risk of AIDS-related death was also high in those who did not meet the treatment criteria or receiving no treatment, when compared to those who had received the antiviral treatment (HR=1.936, 95%CI: 1.145-3.272). CONCLUSION: Factors as: earlier diagnosis of HIV/AIDS cases, provision of CD(4) count testing and antiviral treatment to more cases etc, could decrease the risk for AIDS-related deaths and improve the survival rate on HIV/AIDS cases.