Use Of Separate Systems Research Articles

Latent porosity of planar tris(phenylisoxazolyl)benzene.

Interest in developing separation systems for chemical entities based on crystalline molecules has provided momentum for the fabrication of synthetic porous materials showing selectivity in molecular encapsulation, such as metal-organic frameworks, covalent organic frameworks, hydrogen-bonded organic frameworks, zeolites, and macrocyclic molecular crystals. Among these, macrocyclic molecular crystals have generated renewed interest for use in separation systems. Selective encapsulation relies on the sizes, shapes, and dimensions of the pores present in the macrocyclic cavities; thus, nonmacrocyclic molecular crystals with high selectivity for molecular encapsulation via porosity-without-pore behaviors have not been studied. Here, we report that planar tris(phenylisoxazolyl)benzene forms porous molecular crystals possessing latent pores exhibiting porosity-without-pore behavior. After exposing the crystals to complementary guest molecules, the latent pores encapsulate cis- and trans-decalin while maintaining the structural rigidity responsible for the high selectivity. The encapsulation via porosity without pores is a kinetic process with remarkable selectivity for cis-decalin over trans-decalin with a cis-/trans-ratio of 96:4, which is confirmed by single-crystal X-ray diffraction and powder X-ray diffraction analyses. Hirshfeld surface analysis and fingerprint plots show that the latent intermolecular pores are rigidified by intermolecular dipole‒dipole and π-π stacking interactions, which determines the remarkable selectivity of molecular recognition.

Evaluation of the stability and safety of Venolipid MCT/LCT 20% administered by an all-in-one system in patients after major gastrointestinal surgery

Summary Background & aims A structured fat emulsion containing 50% medium-chain triglycerides (MCTs) is used for total parenteral nutrition for surgical patients. Due to stability and safety considerations, it is commonly infused separately from dextrose solution, increasing cost and risk of contamination. We evaluated the physiochemical stability and clinical safety of an all-in-one admixture. Methods The physiochemical stability of an all-in-one admixture containing 20% medium- and long-chain triglycerides (Venolipid MCT/LCT 20%), dextrose, amino acids, electrolytes, trace elements and vitamins was compared to a two-in-one system. Solutions were stored at 4 °C for 1 week; appearance, pH, osmolality and particle size and distribution were analyzed at room temperature on days 1, 4 and 7. Clinical safety of the all-in-one admixture versus use of separate systems was determined in patients after major upper abdominal surgery in a prospective, randomized, controlled study (total n = 30). Results During storage, the all-in-one admixture maintained its colour. No precipitation, flocculation or creaming was observed. The pH and average particle size did not change significantly. There were no adverse clinical events related to the all-in-one admixture after continuous infusion for 5 days. Conclusion The all-in-one admixture containing Venolipid MCT/LCT 20% can be stored at 4 °C for 1 week and safely used in patients after major upper abdominal surgery.

Life Cycle Assessment of Wastewater Systems: Influence of System Boundaries and Scale on Calculated Environmental Loads

Life cycle assessment (LCA) methodology was used to compare the environmental loads from wastewater systems with different technical solutions. This study compared proposed conventional wastewater systems, both large and small scale, with separation systems: one in which urine is handled separately and one in which black water is treated in a liquid composting process. The study showed that large economies of scale, in environmental terms, could be gained both for the operation and for the construction phase. The separation systems outperformed the conventional systems by showing lower emissions to water and more efficient recycling of nutrients to agriculture, especially of nitrogen but also of phosphorus. This implies that the use of separation systems could significantly reduce the need for, and hence the production of, mineral fertilizers and thus reduce the overall use of energy and phosphate minerals. The combination of large-scale wastewater treatment and urine separation was found to be especially advantageous in these respects. It is concluded that some of the most important environmental advantages of separation systems emerge only when models of wastewater systems are expanded to also include potential effects on the production of fertilizers.