Liquid Desiccant-Polymeric Membrane Dehumidification System for Improved Cooling Efficiency in Built Environments

We have recently demonstrated a new type of moisture absorber using a silicone-based liquid desiccant and a nonporous hydrophilic membrane. The setup consists of a core-shell structure where the desiccant flows inside the hydrophilic membrane (core) surrounded with humid air and confined inside a larger diameter tube (shell). In this work, we propose to extend the capabilities of this moisture absorber prototype by addressing two additional characteristics in order to fully validate its capabilities in the built environment. In the first section of this study, we developed a new setup to demonstrate the regeneration process of the liquid desiccant. The regeneration process takes into account the following parameters: (i) air temperature and relative humidity level, (ii) desiccant temperature and water saturation amount, (iii) air/desiccant contact length, (iv) air and liquid desiccant flow rates. In the second part of this paper, we extend our earlier work with this absorber and propose to further improve its performance. We investigate in detail the water absorption kinetics to favor water access to the bulk liquid desiccant surface through efficient mixing inside a confined volume

Metal complex catalysis in living biological systems

This feature article discusses synthetic metal complexes that are capable of catalyzing chemical transformations in living organisms. Photodynamic therapy exemplifies what is probably the most established artificial catalytic process exploited in medicine, namely the photosensitized catalytic generation of cell-damaging singlet oxygen. Different redox catalysts have been designed over the last two decades to target a variety of redox alterations in cancer and other diseases. For example, pentaazamacrocyclic manganese(II) complexes catalyze the dismutation of superoxide to O-2 and H2O2 in vivo and thus reduce oxidative stress in analogy to the native enzyme superoxide dismutase. Recently, piano-stool ruthenium and iridium complexes were reported to influence cellular redox homeostasis indirectly by catalytic glutathione oxidation and catalytic transfer hydrogenation using the coenzyme NADH, respectively. Over the last few years, significant progress has been made towards the application of non-biological reactions in living systems, ranging from the organoruthenium-catalyzed cleavage of allylcarbamates and a gold-catalyzed intramolecular hydroarylation to palladium-catalyzed Suzuki-Miyaura and Sonogashira cross-couplings within the cytoplasm or on the surface of living cells. The design of bioorthogonal catalyst/substrate pairs, which can passively diffuse into cells, combines the advantages of small molecules with catalysis and promises to provide exciting new tools for future chemical biology studies

Thioether-based anchimeric assistance for asymmetric coordination chemistry with ruthenium(II) and osmium(II)

National Science Foundation of P. R. China; "National Thousand Plan" Foundation of P. R. China; "985 Program" of the Chemistry and Chemical Engineering disciplines of Xiamen University(R)-4-(Alkylthiomethyl)-5,5-dimethyl-2-(2'-hydroxyphenyl)-2-oxazolines are demonstrated to be highly suitable chiral auxiliaries for the two-step conversion of the half-sandwich complex [Ru(eta(6)-C6H6)(bpy)Cl]Cl, bpy = 2,2'-bipyridine, into Delta-configured ruthenium polypyridyl complexes. The tailored thioether substituent at the oxazoline ring is essential for this conversion and not only promotes the removal of the benzene moiety but also controls the absolute metal-centered configuration. Applied to osmium, this strategy resulted in the first highly asymmetric synthesis of Delta-[Os(bpy)(3)](PF6)(2)

Correlation between the Stereochemistry and Bioactivity in Octahedral Rhodium Prolinato Complexes

Controlling the relative and absolute configuration of octahedral metal complexes constitutes a key challenge that needs to be overcome in order to fully exploit the structural properties of octahedral metal complexes for applications in the fields of catalysis, materials sciences, and life sciences. Herein, we describe the application of a proline-based chiral tridentate ligand to decisively control the coordination mode of an octahedral rhodium(III) complex. We demonstrate the mirror-like relationship of synthesized enantiomers and differences between diastereomers. Further, we demonstrate, using the established pyridocarbazole pharmacophore ligand as part of the organometallic complexes, the importance of the relative and absolute stereochemistry at the metal toward chiral environments like protein kinases. Protein kinase profiling and inhibition data confirm that the proline-based enantiopure rhodium(III) complexes, despite having all of the same constitution, differ strongly in their selectivity properties despite their unmistakably mutual origin. Moreover, two exemplary compounds have been shown to induce different toxic effects in an ex vivo rat liver model.</p

Ruthenacarborane–Phenanthroline Derivatives as Potential Metallodrugs

Ruthenium-based complexes have received much interest as potential metallodrugs. In this work, four RuII complexes bearing a dicarbollide moiety, a carbonyl ligand, and a phenanthroline-based ligand were synthesized and characterized, including single crystal diffraction analysis of compounds 2, 4, and 5 and an observed side product SP1. Complexes 2–5 are air and moisture stable under ambient conditions. They show excellent solubility in organic solvents, but low solubility in water

Thermoheliodome Testing: Evaluation Methods for Testing Directed Radiant Heat Reflection☆

Abstract The Thermoheliodome is a prototype experimental pavilion that produces comfort through the manipulation of the mean radiant temperature generated by a combination of evaporative cooling and radiant heat reflection. We present the development of a sensing and analysis method for measuring the impact on radiant temperature and other performance data for the space, along with the initial system measurements. This is an environmental control station through which low cost microcontrollers enable distributed networked nodes to take measurements of relevant system parameters. The system measurements show a reduction of mean radiant temperature by 2-3 °C using evaporative cooling and strategic reflection

Extracting Radiant Cooling From Building Exhaust Air Using the Maisotsenko Cycle Principle

Indirect evaporative cooling has exciting implications for air based thermal comfort. With recent advances in the research and commercialization of Maisotsenko Cycle (M-Cycle), or dew-point, evaporative cooling, thermodynamics can be fully leveraged to provide effectively free air cooling. However, few studies seek to generate cool surfaces by evaporation for radiant cooling. As a method to reduce building energy consumption, such an evapo-radiative system would maintain occupant thermal comfort at higher ventilation air temperatures and provide cooling at low cost. This study explores an analytical model for an M-Cycle evapo-radiative cooling system that derives a 1-D temperature profile throughout an experimental module and compares the outputs to experimental data to begin the model validation process

Condensation-free radiant cooling using infrared-transparent enclosures of chilled panels

Radiant cooling power in the humid climates is inherently limited by condensation. This research investigates a type of radiant cooling methodology whereby the cold temperature source is convectively and conductively isolated from the environment with a membrane transparent to visible radiation to allow supply temperatures to be decreased for radiant cooling systems in humid climates. We conduct an FTIR analysis on three candidate membrane materials and fabricate a prototype experimental test panel that allows for thermal performance evaluation at different panel orientation and depths. Our study shows that for a 5 °C chilled panel temperature, the exterior membrane surface temperature reaches 26 °C in a 32 °C / 70% RH environment resulting in an effective panel temperature of 15.8 °C. Such a panel construction would avoid condensation in many humid environments and allow for radiant cooling without any latent load handling

Continuous synthesis of pyridocarbazoles and initial photophysical and bioprobe characterization

Pyridocarbazoles when ligated to transition metals yield high affinity kinase inhibitors. While batch photocyclizations enable the synthesis of these heterocycles, the non-oxidative Mallory reaction only provides modest yields and difficult to purify mixtures. We demonstrate here that a flow-based Mallory cyclization provides superior results and enables observation of a clear isobestic point. The flow method allowed us to rapidly synthesize ten pyridocarbazoles and for the first time to document their interesting photophysical attributes. Preliminary characterization reveals that these molecules might be a new class of fluorescent bioprobe

Resolving indoor shortwave and longwave human body irradiance variations for mean radiant temperature and local thermal comfort

A spatially and directionally resolved longwave and shortwave radiant heat transfer model is presented via a series of experiments in a thermal lab to input surface temperatures and geometries, as well as skin temperature readings from a human subject, in order to test mean radiant temperature (MRT) and thermal comfort results for the person. Combining novel scanning and thermography methods together with ray-tracing simulation, high-resolution thermal models are derived fully characterizing the longwave and shortwave radiant heat fluxes in space and resolving the impact of these variations on MRT. The study demonstrates the significant amount of spatial variation of both shortwave and longwave radiant heat transfer on MRT through the room and also across body segments: the experimental results show variations of up to 14.5°C across the room, leading to PMV comfort variations from −0.27 to 2.45, clearly demonstrating the importance of mapping the entire radiant field rather than assuming one MRT value for a thermal zone. Furthermore, local radiant temperature, newly defined Body Segment Plane Radiant Temperature (BSPRT), variations across the body of more than 30°C are found. Finally, a detailed human thermo-physiology model was used to evaluate the possible variation in thermal sensation between the different body segments due to the large differences in local MRT