The Evolution of Intermittent Mandatory Ventilation.

Intermittent mandatory ventilation (IMV) is one kind of breath sequence used to classify a mode of ventilation. IMV is defined as the ability for spontaneous breaths (patient triggered and patient cycled) to exist between mandatory breaths (machine triggered or machine cycled). Over the course of more than a century, IMV has evolved into 4 distinct varieties, each with its own advantages and disadvantages in serving the goals of mechanical ventilation (ie, safety, comfort, and liberation). The purpose of this paper is to describe the evolution of IMV, review relevant supporting evidence, and discuss the rationales for each of the 4 varieties. Also included is a brief overview of the background information required for a proper perspective of the purpose and design of the innovations. Understanding these different forms of IMV is essential to recognizing the similarities and differences among many dozens of different modes of ventilation. This recognition is important for clinical application, education of caregivers, and research in mechanical ventilation.

The Effect of Inspiratory Effort on Circuit Compensation for Volume-Targeted Modes.

BACKGROUND: Critical-care ventilators provide patient circuit compensation (CC) to counteract the loss of volume due to patient circuit compliance. No studies show the effect of inspiratory efforts (indicating maximal value of the muscle pressure waveforms [Pmax]) on CC function. The goal of this study was to determine how Pmax affects volume delivery with or without CC for both volume control continuous mandatory ventilation with set-point targeting scheme (VC-CMVs) and pressure control continuous mandatory ventilation with adaptive targeting scheme (PC-CMVa) modes on the Servo-u ventilator. METHODS: A breathing simulator was programmed to represent an adult with moderate ARDS with different Pmax. It was connected to a ventilator set to VC-CMVs or PC-CMVa. The change in tidal volume (ΔVT) was defined as the difference between VT with CC on versus off. VT error was defined as the difference between the simulator displayed VT and the set VT with CC on versus off. RESULTS: For both VC-CMVs and PC-CMVa modes, ΔVT decreased as Pmax increased. The VT error decreased as Pmax increas-ed for VC-CMVs. In contrast, VT error increased on PC-CMVa mode as Pmax increased and peaked 39.0% for Pmax = 15 cm H2O. For both modes, the difference in VT errors for CC on versus CC off decreased as Pmax increased. CONCLUSIONS: CC corrected the delivered VT for volume lost due to compression in the patient circuit as expected. This compensation volume decreases as airway pressure drops due to patient Pmax.

[Contrast study on natural radioactive nuclides contents of rice between Xiangshan uranium deposit area, Jiangxi and non-uranium depsoit area].

The contents of natural radioactive nuclides such as uranium and thorium in paddies were analyzed and compared by means of ICP-MS. Totally 14 paddy samples were distinguished into two groups and collected from two rice planting area. One group (12 paddy samples) was collected from the Xiangshan uranium deposit area, Jiangxi province; while the other group (2 samples) collected from non-uranium deposit suburban area of Fuzhou city, Jiangxi, as comparison samples. The distance between the two sampling areas is about 80 kilometers. Before analysis, those paddy samples were continuously carbonized by two hours first, then continuously incinerated for 8 hours at the temperature of 600 degrees centigrade. The results show that the uranium contents in the paddy ash of samples gotten from Xiangshan uranium deposit area range from 0.053 to 1.482 microg x g(-1). The uranium contents of two comparison paddy samples ash are 0.059 and 0.061 microg x g(-1), respectiovely. The average uranium content of paddy ash of uranium deposit area is 0.323 microg x g(-1). Compared with the comparison samples, the uranium contents of paddy ash of uranium deposit area are considerably high, 5.30 times that of non-uranium deposit area. The thorium contents in paddy ash of the uranium deposit area, however, are relatively low and less than that of samples collected from non-uranium deposit area, which range from 0.029 to 0.311 microg x g(-1); The average level is 0.104 microg x g(-1), only about 50% of that of paddy ash sampled from non-urnaium deposit area. Moreover, there is significant linearity correlation between uranium and thorium contents of paddy sampled from Xiangshan uranium deposit area. The positive effects show that the thorium contents of paddy increase as uranium contents of paddy in uranium deposit area increase. The causes for the remarkable difference in uranium contents in paddy between urianium deposit area and non-uranium deposit area are not clear yet. The research on this topic, however, is very important and significant to the regional rice quality and food security.

Increased flammability hazard when ionic liquid [C6mim][Cl] is exposed to high temperatures.

Industrial use of ionic liquids may require exposure to high temperatures. We demonstrate that such applications may result in an increase in flammability hazard due to chemical decomposition. The ionic liquid, 1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]), was selected as the study sample. The flash point and other properties were measured using a commercially available flash point analyzer, a thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR), an integrated TGA-FTIR system, and pyrolysis-gas chromatography-mass spectrometer. We found that thermal decomposition occurred with the release of chloromethane, 1-chlorohexane, 1-hexene, 1-methylimidazole, and 1-hexylimidazole as [C6mim][Cl] was heated. Such decomposition changed the components of the residual liquid phase. Vaporization of the [C6mim][Cl] decomposition products increased the mass loss rate on TGA as [C6mim][Cl] was heated to high temperatures, resulting in a high concentration of flammable gases and a decrease in the flash point, which increased the flammability hazard.

[Effects of soil on the concentration of rare earth in Nanfeng orange].

Nanfeng orange is a famous fruit in the world, but the content of rare earth in the fruit and its relation to the content in soil were little studied. The present paper studied the contents of rare earth in Nanfeng orange fruit and the effects of soil planting Nanfeng orange on the contents of rare earth in Nanfeng orange fruit by ICP-MS/ICP-AES in order to find the relation of rare earth content in the soil to that in Nanfeng orange fruit. The results showed that ten kinds of rare earths were detected, namely La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Yb, whose contents range from 0.63 to 0.01 ng x g(-1), while the contents of the ten elements range from 29.36 to 0.07 microg x g(-1) in the soil All data showed that the content of rare earth in fruits is right relative to that in soil. So the authors can conclude that fertilizing with rare earth should be the best way to enhance the content of rare earth in Nanfeng orange fruits.

[Application of ICP-MS/ICP-AES to detecting factors influencing the quality of Nanfeng orange].

Nanfeng orange is a world famous fruits, but its quality changes remarkably with the producing area. The present paper studied the contents of heavy metal mineral elements and microelements in soil planting Nanfeng orange by ICP-MS/ICP-AES and in order to find the dominant factors that affect the quality of Nanfeng orange in soil. The results showed that the contents of B, P, K, Mg and Ca, especially B, P and K were much higher in soil where the quality of Nanfeng orange is palatable than those where Nanfeng orange is unpalatable; but the contents of Fe, Mn, Si, Cu and Zn were lower in soil where the quality of Nanfeng orange is palatable than those where Nanfeng orange is unpalatable. These data indicate that B, P, K, Mg and Ca, especially B, P and K, affect the quality of Nanfeng orange significantly.