Synthesis of Long Alkyl and Fluoroalkyl Substituted Siloxane Copolymers for the Water Repellency of Rammed Earth Walls.

Rammed earth in a built environment has vapor diffusion characteristics and humidity control abilities, each of which is respectively attributed to the porous structures and the hydrophilic properties. Indeed, these structures and properties allow for the easy absorbance of water particles, hence affecting the durability of a rammed earth wall. This paper presents the water-repellency method for rammed earth walls, which utilizes siloxane copolymers containing fluorine. The water-repellent properties are investigated by measuring the contact angle, water absorption rate, and compressive strength after spray-coating with the synthesized siloxane copolymers on the surface of the rammed earth specimens under study. The water contact angle of the specimen, coated with a siloxane copolymer containing 10 mol.% of a silane monomer with a fluorine group, is about 140°. The water absorption of the specimen obtained after immersing in water for 24 h is low, at about 3.5 wt.%. In addition, the compressive strength remains more than 80% of the corresponding strength of the specimen which is not immersed in water. It is confirmed that the use of a 10% by volume of the siloxane copolymer containing the fluorine group may enhance the water-repellent performance and economic competitiveness.

2,3-Butanedione monoxime facilitates successful resuscitation in a dose-dependent fashion in a pig model of cardiac arrest.

PURPOSE: Ischemic contracture compromises the hemodynamic effectiveness of cardiopulmonary resuscitation (CPR) and resuscitability from cardiac arrest. In a pig model of cardiac arrest, 2,3-butanedione monoxime (BDM) attenuated ischemic contracture. We investigated the effects of different doses of BDM to determine whether increasing the dose of BDM could improve the hemodynamic effectiveness of CPR further, thus ultimately improving resuscitability. METHODS: After 16minutes of untreated ventricular fibrillation and 8minutes of basic life support, 36 pigs were divided randomly into 3 groups that received 50mg/kg (low-dose group) of BDM, 100mg/kg (high-dose group) of BDM, or an equivalent volume of saline (control group) during advanced cardiovascular life support. RESULTS: During advanced cardiovascular life support, the control group showed an increase in left ventricular (LV) wall thickness and a decrease in LV chamber area. In contrast, the BDM-treated groups showed a decrease in the LV wall thickness and an increase in the LV chamber area in a dose-dependent fashion. Mixed-model analyses of the LV wall thickness and LV chamber area revealed significant group effects and group-time interactions. Central venous oxygen saturation at 3minutes after the drug administration was 21.6% (18.4-31.9), 39.2% (28.8-53.7), and 54.0% (47.5-69.4) in the control, low-dose, and high-dose groups, respectively (P<.001). Sustained restoration of spontaneous circulation was attained in 7 (58.3%), 10 (83.3%), and 12 animals (100%) in the control, low-dose, and high-dose groups, respectively (P=.046). CONCLUSION: 2,3-Butanedione monoxime administered during CPR attenuated ischemic contracture and improved the resuscitability in a dose-dependent fashion.

Femoral venous oxygen saturation obtained during CPR predicts successful resuscitation in a pig model.

PURPOSE: Central venous oxygen saturation has been shown to reflect the adequacy of tissue oxygenation during cardiopulmonary resuscitation (CPR), thereby enabling the assessment of CPR quality and the prediction of restoration of spontaneous circulation (ROSC). The femoral vein can be easily accessed during CPR. We determined if femoral venous oxygen saturation (SFVO2) values obtained during CPR could reliably predict ROSC in a pig model. METHODS: After 15 minutes of untreated ventricular fibrillation followed by 8 minutes of basic life support, 19 pigs underwent advanced cardiovascular life support. During advanced cardiovascular life support, femoral venous blood samples were obtained at 4-minute intervals. The abilities of SFVO2 and coronary perfusion pressure (CPP) to predict ROSC were evaluated by calculating the areas under receiver operating characteristic curves (AUCs). RESULTS: Eight pigs (42.1%) achieved ROSC. The resuscitated animals had significantly higher CPP (P < .001) and SFVO2 (P < .001) values than the nonresuscitated animals, and there was a significant correlation between SFVO2 and CPP values (r = 0.684; P < .001). The CPPs of the resuscitated and nonresuscitated animals overlapped considerably; however, there was minimal overlap between the 2 groups for SFVO2. Femoral venous oxygen saturation significantly predicted ROSC with an AUC of 0.997 (95% confidence interval, 0.911-1.000; P < .001), and it had a larger AUC than CPP (AUC, 0.964; 95% confidence interval, 0.855-0.997; P < .001). The AUC difference, however, was not statistically significant (P = .157). CONCLUSION: In this study, SFVO2 values obtained during CPR exhibited a significant correlation with CPP and reliably predicted ROSC.

Augmentation of the cooling capacity of refrigerated fluid by minimizing heat gain of the fluid using a simple method of cold insulation.

OBJECTIVES: This study was undertaken to determine how rapidly refrigerated fluids gain heat during bolus infusion and to determine whether the refrigerated fluids could be kept cold by a simple cold-insulation method. METHODS: One liter of refrigerated fluid was run through either a 16-gauge catheter (16G(-) and 16G(+) groups) or an 18-gauge catheter (18G(-) and 18G(+) groups) while monitoring the temperature in the fluid bag and the outflow site. In the 16G(+) and the 18G(+) groups, the fluid bag was placed with an ice pack inside an insulating sleeve during the fluid run. RESULTS: In the 16G(-) and the 18G(-) groups, the outflow temperature increased to 10-12 degrees C during the fluid run. Meanwhile, outflow temperatures in the 16G(+) and the 18G(+) groups remained below 4.6 and 6.8 degrees C, respectively. The temperatures differed significantly between the 16G(-) and the 16G(+) groups (p < 0.001) and between the 18G(-) and the 18G(+) groups (p < 0.001), respectively. CONCLUSIONS: Substantial heat gain occurred in the refrigerated fluid even during the relatively short duration of bolus infusion. The heat gain could, however, be easily minimized by cold insulation of the fluid bag.

Performance of an automated external defibrillator in a moving ambulance vehicle.

AIM OF THE STUDY: The available data suggest that automated external defibrillators (AED) can be safely used in vibration-like moving conditions such as rigid inflatable boats and aircraft environments. However, little literature exists examining their performance in a moving ambulance. The present study was undertaken to determine whether an AED is able to analyse the heart rhythm correctly during ambulance transport. METHODS: An ambulance was driven on paved (20-100 km/h) and unpaved (10 km/h) roads. The performance of two AED devices (CU ER 2, CU Medical Systems Inc., Korea, and Heartstart MRx, Phillips, USA) was determined in a moving ambulance using manikins. Vibration intensity was measured simultaneously with a digital vibrometer. AED performance was then evaluated again on manikins and on a swine model under simulated vibration intensities (0.5-5m/s(2)) measured by the vibrometer in the previous phase of the investigation. RESULTS: The vibration intensity increased with increasing speeds on paved roads (1.98+/-0.44 m/s(2) at 100 km/h). While driving on unpaved roads, it increased to 6.40+/-1.06 m/s(2). Both AED algorithms analysed the heart rhythm correctly under resting state. When tested on pigs, both algorithms showed substantially degraded performances, even at low vibration intensities of 0.5-1m/s(2), which corresponded to vibration intensities while driving on paved roads at 20-60 km/h. This study also showed that electrocardiograms generated on manikins were more resistant to motion artifacts than were the pig electrocardiograms. CONCLUSION: Ambulance personnel should consider the possibility of misinterpretation by an AED when this device is used while transporting a patient.