Preparation and Reactions of Zincated Thymine Derivatives

Preparation and Reactions of Zincated Thymine Derivative

Infrared Optical Constants of Crystalline Sodium Chloride Dihydrate: Application To Study the Crystallization of Aqueous Sodium Chloride Solution Droplets at Low Temperatures

Complex refractive indices of sodium chloride dihydrate, NaCl·2H₂O, have been retrieved in the 6000–800 cm^–1 wavenumber regime from the infrared extinction spectra of crystallized aqueous NaCl solution droplets. The data set is valid in the temperature range from 235 to 216 K and was inferred from crystallization experiments with airborne particles performed in the large coolable aerosol and cloud chamber AIDA at the Karlsruhe Institute of Technology. The retrieval concept was based on the Kramers–Kronig relationship for a complex function of the optical constants <i>n</i> and <i>k</i> whose imaginary part is proportional to the optical depth of a small particle absorption spectrum in the Rayleigh approximation. The appropriate proportionality factor was inferred from a fitting algorithm applied to the extinction spectra of about 1 μm sized particles, which, apart from absorption, also featured a pronounced scattering contribution. NaCl·2H₂O is the thermodynamically stable crystalline solid in the sodium chloride–water system below the peritectic at 273.3 K; above 273.3 K, the anhydrous NaCl is more stable. In contrast to anhydrous NaCl crystals, the dihydrate particles reveal prominent absorption signatures at mid-infrared wavelengths due to the hydration water molecules. Formation of NaCl·2H₂O was only detected at temperatures clearly below the peritectic and was first evidenced in a crystallization experiment conducted at 235 K. We have employed the retrieved refractive indices of NaCl·2H₂O to quantify the temperature dependent partitioning between anhydrous and dihydrate NaCl particles upon crystallization of aqueous NaCl solution droplets. It was found that the temperature range from 235 to 216 K represents the transition regime where the composition of the crystallized particle ensemble changes from almost only NaCl to almost only NaCl·2H₂O particles. Compared to the findings on the NaCl/NaCl·2H₂O partitioning from a recent study conducted with micron-sized NaCl particles deposited onto a surface, the transition regime from NaCl to NaCl·2H₂O is shifted by about 13 K to lower temperatures in our study. This is obviously related to the different experimental conditions of the two studies. The partitioning between the two solid phases of NaCl is essential for predicting the deliquescence and ice nucleation behavior of a crystalline aerosol population which is subjected to an increasing relative humidity

Flow chart study cohort and evaluated parameters.

Fig 1 shows a flow chart on the outcome of patients with different duration of ICU treatment with an overview of available numbers of examined parameters at the respective time points.</p

Data set.

(XLSX)</p

Clinician satisfaction and preference for central venous catheter systems promoting patient safety, ease-of-use and reduced clinician error

Central venous catheters (CVC) are frequently utilized with limited data on user preferences. A simulation/survey-based study was conducted among anesthesia providers to evaluate attitudes toward general CVC system attributes, and satisfaction with elements of the most-commonly used and a novel CVC system. Forty providers completed a simulation using both CVC systems and a 29-item questionnaire, including multiple-choice, free-text, ranking, and Likert-like questions. Ranking scores were reported using a scale of 0 (least important/satisfactory) to 100 (most important/satisfactory). Statistical significances were evaluated via Wilcoxon signed-rank sum test. Participants chose (mean±SD) patient safety (83.9 ± 25.3), ease-of-use (64.6 ± 26.1), and reduced risk for error (61.1 ± 26.7) as the most important attributes when considering a CVC system. Satisfaction levels were significantly higher for the novel system: overall (p p p p = 0.012). Mean satisfaction scores were significantly higher for the novel system’s potential to reduce 5 of 7 common issues, including clinician error (p p  Anesthesia providers preferred CVC systems promoting patient safety, ease-of-use and reduce clinician error. Significantly higher (p < 0.05) satisfaction scores were awarded to a novel system featuring a sequentially organized tray, enhanced labeling, and a guidewire funnel.</p

Characteristics of complete cases (patients with duration of ICU treatment >48 h) compared to patients with ICU treatment <48 h.

Characteristics of complete cases (patients with duration of ICU treatment >48 h) compared to patients with ICU treatment <48 h.</p

Characteristics of study cohort.

Characteristics of study cohort.</p

Fig 2 -

ROC analysis of mortality by maximum lactate (A), minimum base excess (B) and minimum pH (C) in the first 24 h after admission. Abbreviations: AUROC, Area under the receiver operating characteristics curve; max., maximum; min., minimum; sens., sensitivity; spec., specificity; J, Youden-Index.</p

Univariate correlations with mortality: ROC and Cox regression.

Univariate correlations with mortality: ROC and Cox regression.</p

Univariate hazard ratios for subgroups of primary diagnosis.

Univariate hazard ratios for subgroups of primary diagnosis.</p