Simultaneous Determination of pH, CO2 Content, and Cell Volume in 0.1 ml. Aliquots of Cutaneous Blood

Abstract 1. A modificationhas been described for the Shock and Hastings technic of determining simultaneously, in 0.1 ml. aliquots of blood, the pH,CO2. content, and packed cell volume. Advantages of the modification are collection and handling of the blood in a way that avoids the use of oil, and a modified design of the micropipets so that pH readings can be obtained in a filter photometer. 2. The standard error of measurement of a single reading was ±0.009 for the pH, and ±0.22mM/L. for the whole blood CO2. concentration. The reproducibility of the photocolorimetric pH measurement was slightly better than that obtainable with the most accurate commercially available glass electrode. 3. Results have been presented to show that blood can be handled in the presence of brief, limited, exposure to air with no detectable change in pH and only negligible change in CO2 content (decrease of less than 0.2 mM/L.). Errors attributable to collection and handling of cutaneous blood by this "virtual anaerobic" technic are not of significant magnitude. 4. Results have also been presented in confirmation of the fact that arterial and cutaneous blood are virtually identical in acid-base properties. A sample of as little as 0.5 ml. of cutaneous blood, analyzed by the microtechnic, provides the necessary and sufficient data for a description of the state of acid-base balance. This includes calculation of the physiologically important variables, arterial CO2 pressure, and whole-blood buffer base concentration, thus furnishing a measure of the respiratory factor and the metabolic factor in any acid-base disturbance. With a sample size of 1.5 ml. it is also possible to determine other individual constituents of plasma, such as sodium, chioride, and total protein. 5. The technic is useful in the study of clinical disturbances of acid-base balance, especially in infants and children.</jats:p

Interfacial Effects during Rapid Lamination within MAPbI3 Thin Films and Solar Cells

Although hybrid halide perovskite solar cells (PSCs) have recently reached record efficiency among thin film photovoltaic technologies, the stability of these devices remains a pressing problem for commercialization. Lamination processes represent an attractive means of fabricating PSCs due to their self-encapsulating nature and compatibility with high-throughput manufacturing methods. These techniques often involve high temperature and pressure, which represents an underexplored region of the perovskite processing parameter space. In this work, we investigate the behavior of the archetypal halide perovskite, methylammonium lead iodide (MAPbI3), under elevated temperatures and pressures. We also characterize the interactions of MAPbI3 with the commonly used electron and hole transport layers (ETL and HTL) SnO2 and NiOx and find that the latter is particularly susceptible to detrimental interactions at temperatures not far above those commonly used in conventional perovskite film deposition techniques, with deleterious effects on device performance. SnO2 can also evince reactions with the perovskite precursor methylammonium iodide but is more robust than NiOx. Applying the above knowledge, we investigate a laminated bifacial device fabrication strategy that mitigates intrinsic and interface-related threats to the perovskite absorber and report that such devices can reach power conversion efficiencies of >12%. These results not only advance the state of the art in laminated PSCs but also reveal heretofore unknown interactions in commonplace device architectures that should be taken into account when developing device fabrication schemes