Investigation of Thermodynamic Properties of Dimethyl Phosphate-Based ILs for Use as Working Fluids in Absorption Refrigeration Technology

In the current research, the binary solution containing ionic liquid (IL), 1-ethyl-1-methylmorpholinium dimethyl phosphate ([C₁C₂MOR][DMP]), 1-ethyl-1-methylpiperidinium dimethyl phosphate ([C₁C₂PIP][DMP]), or N,N,N-triethyl-N-methylammonium dimethyl phosphate ([N_1,2,2,2][DMP]) with ethanol are investigated as new working fluids for absorption refrigeration technology. The IL was mixed with ethanol, which was considered as a refrigerant. Experimental (vapor + liquid) phase equilibria (VLE) of these binary systems were measured by an ebulliometric method within a temperature range from T = (328.15 to 348.15) K with an increment of 10 K and pressures up to 90 kPa. Experimental VLE data were correlated using non-random two-liquid (NRTL) within the maximum average relative deviation of 0.45%, which confirms the effectiveness of using such a model for calculations. Each of the proposed binary systems exhibit a negative deviation from Raoult's law, which is a very important characteristic for working pairs used in absorption heat pumps or absorption refrigerators. From a technological point of view, measurements of physicochemical properties play an important role. In this research, liquid density and dynamic viscosity were determined at temperatures from T = (293.15 to 338.15) K at ambient pressure over the whole concentration range. These properties were correlated using empirical equations. From experimental density data, the excess molar volumes were determined and correlated using the Redlich-Kister type equation. Ionic liquid: [C₁C₂MOR][DMP] and [C₁C₂PIP][DMP] were synthesized and characterized using NMR analysis. The thermophysical characterization of pure ILs, including glass transition temperature (T_g) and heat capacity at the glass transition temperature (Δ_gC_p), was determined using the differential scanning calorimetry technique (DSC) at atmospheric pressure. In this work, the combination of basic studies on the effect of the cation structure of an ionic liquid on the properties of their solutions with ethanol and the possibility of future application of the tested systems in a viable refrigeration system are presented.

A blended learning teaching strategy strengthens the nursing students' performance and self-reported learning outcome achievement in an anatomy, physiology and biochemistry course - A quasi-experimental study

In nursing, bioscience is regarded as one of the cornerstones of nursing practice. However, bioscience disciplines as anatomy, physiology and biochemistry are considered challenging for students and the failure rate is high. In this study we explore a blended learning teaching strategy in an anatomy, physiology and biochemistry course for first year Bachelor nursing students. In the blended learning teaching strategy, short narrated online digital resources of bioscientific terms and concepts were integrated into the teaching design along with digital metacognitive evaluations of learning outcomes. Results show that compared to students receiving traditional face-to-face teaching, the students with a blended learning approach performed better on their national exam with a small to medium effect size (Cohen's d=0.23). Student course evaluations supported the blended learning delivery with small to medium effect sizes. The students reported that the digital resources supported their learning outcome achievement, that they better understood the teacher's expectations and that they were more satisfied with their virtual learning environment. This study adds to the growing literature of blended learning effectiveness in higher education, and suggests the use of digital resources as an enrichment of teaching and enhancement of students' study experience.

Molecular simulation data for the vapor-liquid phase equilibria of binary mixtures of HFO-1123 with R-32, R-1234yf, R-1234ze(E), R-134a and CO2 and their modelling by the PCP-SAFT equation of state

In this Data in Brief article, we present predictive data for the vapor-liquid equilibria of the binary mixtures of HFO-1123 with R-32, HFO-1234yf, HFO-1234ze(E), R-134a and CO₂ from molecular simulation. The VLE in the binary mixtures are then modeled by the PCP-SAFT equation of state. Therefore we determined PCP-SAFT parameters for the pure HFO compounds as well as binary interaction parameters for all mixtures. The simulation data and the PCP-SAFT modelling are discussed in a related research article (Raabe, 2019).

Second generation optical coherence tomography: Preliminary experience in pancreatic and biliary strictures

INTRODUCTION

Evaluation of indeterminate biliary strictures remains a diagnostic challenge. Optical coherence tomography (OCT) provides in-vivo, wide-field, cross-sectional imaging at the microstructure level. We present the first preliminary data using a second-generation OCT system using volumetric laser endomicroscopy (VLE) in biliary and pancreatic duct strictures.

METHODS

10 consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and OCT for indeterminate biliary or pancreatic stricture evaluation were captured in a registry. Following ductal cannulation and guidewire placement, an imaging probe was advanced into the duct and images were interpreted in-vivo. Tissue sampling with cytology brushing was performed in all cases. Demographics, procedural information, imaging data, and histologic findings were collected.

RESULTS

8 had biliary strictures and 2 had pancreatic duct strictures. VLE was successfully performed in all patients (100%). Histology revealed malignancy in 3 patients (cholangiocarcinoma) and benign disease in the remaining 7 patients, including 1 with primary sclerosing cholangitis (PSC). All 3 cholangiocarcinoma patients demonstrated epithelial thickening with projections, a hyper-reflective surface with shadowing, and layering effacement (loss of visualization and haziness of inner mucosal layers). A PSC patient showed onion skin layering and hyper-reflective sub-surface structures but with preserved wall layering. Benign biliary strictures showed clearly delineated epithelial layer and clear layering in the inner mucosal layers as well as the presence of dilated hypo-reflective structures.

CONCLUSION

There may be characteristic VLE findings for malignant, inflammatory, and benign biliary strictures.

E learning in surgery

E learning means use of electronic media and information technologies in education. Virtual learning environment (VLE) provides learning platforms consisting of online tools, databases and managed resources. This article is a review of use of E learning in medical and surgical education including available evidence favouring this approach. E learning has been shown to be more effective, less costly and more satisfying to the students than the traditional methods. E learning cannot however replace direct consultant supervision at their place of work in surgical trainees and a combination of both called blended learning has been shown to be most useful. As an example of university-based qualification, one such programme is presented to clarify the components and the process of E learning. Increasing use of E learning and occasional face to face focussed supervision by the teacher is likely to enhance surgical training in the future.