Metal-organic frameworks for water adsorption applications in the automotive filtration industry

In dieser Arbeit werden verschiedene MOF Materialien die sich für die Wasseradsorption eignen hinsichtlich Ihrer Wasseradsorptionseigenschaften untersucht. Das vielversprechendste Material wird ausgewählt und an einem Prüfstand für Lufttrocknerkartuschen untersucht. Für diese Messungen ist eine geeignete Formgebung des Pulvers von Nöten, welche eine wichtige Rolle in dieser Arbeit spielt. Das Material Cu3(BTC)2 wurde hier zu monolithischen Formkörpern verarbeitet. Eine weitere Art der Formgebung war das Pressen von Papieren sowie das direkte Kristallwachstum auf Zellulose Fasern. Desweiteren wurden die Materialien hinsichtlich der Trocknung von n-Heptan untersucht, was hier als Referenz für Dieselkraftstoffe herangezogen wurde. Die Analytik wurde mittels Karl-Fischer Titration duchgeführt. MOF Materialien wurden in beiden Fällen mit kommerziell verwendeten Zeolithen und Silikagel verglichen.Metal-organic frameworks (MOFs) were investigated for their possible use in drying of compressed air in air braking systems for commercial vehicles. Another possible application was the drying of diesel fuel. In this context, n-heptane was chosen as a reference for diesel fuel. Selected metal-organic frameworks were characterized regarding the water adsorption properties by recording water adsorption isotherms. The most promising material was further investigated on a air-drying cartridge test rig. In order to perform these tests, the powder had to be processed to monolithic structures, beads or paper sheets,i.e. a shape that is suitable for the given application. The MOF Cu3(BTC)2 was sucessfully extruded to monolithic structures, which were used in the test rig experiments. Another possibility for immobilization of Cu3(BTC)2 was the crystal growth on pulp fibers. N-heptane drying isotherms were measured on selected samples making use of Karl-Fischer coulometric titration. In both applications, MOF materials were compared with silica based desiccants

Enhanced Synthesis of Metal-Organic Frameworks on the Surface of Electrospun Cellulose Nanofibers

This study reports the in situ crystal growth of HKUST-1 on electrospun cellulose nanofibers. Two different methods for introducing carboxyl groups on the nanofiber surface were used; HKUST-1 was then synthesized on the cellulose nanofiber surface using a layer-by-layer approach. The distribution of HKUST-1 on the nanofiber surface was highly dependent on the type of anionic pretreatment. The loading of HKUST-1 on the nanofiber surface could be controlled by the layer-by-layer synthesis and the BET surface area could be increased by a factor of 44 to 440 m2 g-1

The Influence of Cu\u3csub\u3e3\u3c/sub\u3e(BTC)\u3csub\u3e2\u3c/sub\u3e metal organic framework on the permeability and perm-selectivity of PLLA-MOF mixed matrix membranes

Poly(l-lactic acid) (PLLA) - 20% (w/w) and Cu3(BTC)2 metal organic framework (MOF) based mixed matrix membranes (MMMs) were fabricated by a vertical corotating twin screw microcompounder followed by an injection molding process. Water vapor, CO2, O2, and selected aroma mass transfer properties of PLLA and PLLA MMMs were evaluated. The CO2/O2 perm-selectivity of PLLA (αCO2/O2) MMMs increased from 7.6 to 10.3 with the incorporation of 20% Cu3(BTC)2 MOF. Gravimetric permeability studies of trans-2-hexenal performed at 23°C and 50% RH indicated that permeability coefficient of PLLA MMMs increased by around 60% as compared to regular PLLA film. However, no changes in mass transfer rates were observed for acetaldehyde. Furthermore, the thermal processing parameters as well as the presence of MOF did not show any significant effect on the molecular weight of the PLLA matrix nor on the crystalline structure of the Cu3(BTC)2 MOF, which was confirmed by both gel permeation chromatography and X-ray diffraction studies

Hygrothermal simulation-informed design of mesoporous desiccants for optimised energy efficiency of mixed mode air conditioning systems

This paper describes an optimization technique using hygrothermal numerical modelling to determine an ideal and unknown isotherm in order to inform the design of optimised mesoporous desiccants. Their suitability for passive humidity buffering as well as their impact on energy efficiency was assessed when assisting a mixed mode air-conditioning (AC) system. Three clear stages of water vapour adsorption were found that strongly correspond to the Dw gradient when assessing the kinetics of adsorption and exchange rates for periodic moisture loads. Consistent agreement was found between the latent heat of dehumidification used by the AC system and the desiccant decay time after successive sorption loop cycles. This confirmed the material's suitability for specific applications and was found to be highly sensitive to the portion of the isotherm between φi,L - φi,U (Dw gradient), compared with full adsorption capacity (total w) when assessing total energy consumption. The experimental results of sorption kinetics appeared to be slightly underestimated between the Dw gradient and the response time to reach equilibrium moisture content (EMC). The major underestimations were found to be consistent with the kinetics of adsorption/desorption when analysing their significance based on w differences. These were largely attributed to a combination of adsorption kinetics (time-response) and adsorption/desorption hysteresis. However, this was not evident when comparing long-term experimental data and numerical estimations for water vapour sorption isotherms, since numerical model accurately predicted them. This suggests that both adsorption kinetics and the scanning curve prediction, within a hysteresis loop, are not accurately represented by current hygrothermal models and are hence a priority for future research

Sublethal necroptosis signaling promotes inflammation and liver cancer

It is currently not well known how necroptosis and necroptosis responses manifest in vivo. Here, we uncovered a molecular switch facilitating reprogramming between two alternative modes of necroptosis signaling in hepatocytes, fundamentally affecting immune responses and hepatocarcinogenesis. Concomitant necrosome and NF-κB activation in hepatocytes, which physiologically express low concentrations of receptor-interacting kinase 3 (RIPK3), did not lead to immediate cell death but forced them into a prolonged "sublethal" state with leaky membranes, functioning as secretory cells that released specific chemokines including CCL20 and MCP-1. This triggered hepatic cell proliferation as well as activation of procarcinogenic monocyte-derived macrophage cell clusters, contributing to hepatocarcinogenesis. In contrast, necrosome activation in hepatocytes with inactive NF-κB-signaling caused an accelerated execution of necroptosis, limiting alarmin release, and thereby preventing inflammation and hepatocarcinogenesis. Consistently, intratumoral NF-κB-necroptosis signatures were associated with poor prognosis in human hepatocarcinogenesis. Therefore, pharmacological reprogramming between these distinct forms of necroptosis may represent a promising strategy against hepatocellular carcinoma

Psychosocial work load and stress in the geriatric care

<p>Abstract</p> <p>Background</p> <p>Due to the decrease in informal care by family members and the demographic development, the importance of professional geriatric care will rise considerably. Aim of this study was to investigate the psychosocial workplace situation for employees in this profession.</p> <p>Methods</p> <p>The German version of the COPSOQ (Copenhagen Psychosocial Questionnaire) was used for the assessment of psychosocial factors at work. The instrument includes 22 scales and 3 single items concerning demands, control, stress, support, and strain.</p> <p>Results between two study groups of geriatric care were compared to each other as well as to employees in general hospital care and a general population mean (COPSOQ database).</p> <p>Statistical analysis included t-tests, ANOVA and multiple comparisons of means. Statistical significance (p < 0.01, two-tailed) and a difference of at least 5 points in mean values were defined as the relevant threshold.</p> <p>Results</p> <p>In total 889 respondents from 36 institutions took part in the study. 412 worked in Home Care (HC), 313 in Geriatric Nursing Homes (GNH), 164 in other professions (e.g. administration).</p> <p>Comparison between HC and GNH showed more favourable values for the first group for the most scales, e.g. lower quantitative and emotional demands and less work-privacy conflict, better possibilities for development etc. Compared to external values from the German COPSOQ database for general hospital care (N = 1.195) and the total mean across all professions, COPSOQ-total (N = 11.168), the results are again positive for HC workers on most of the scales concerning demands and social support. The only negative finding is the very low amount of social relations at work due to the obligation to work alone most of the time. Employees in GNH rate predictability, quality of leadership and feedback higher when compared to general hospital care and show some further favourable mean values compared to the COPSOQ mean value for all professions. A disadvantage for GNH is the high rating for job insecurity.</p> <p>A supplementary subgroup analysis showed that the degree of negative evaluation of psychosocial factors concerning demands was related to the amount of working hours per week and the number of on-call duties.</p> <p>Conclusions</p> <p>Compared to employees in general hospital care and the COPSOQ overall mean value across all professions, geriatric care employees and especially home care workers evaluate their psychosocial working situation more positive for most aspects. However, this seems partly due to the very high proportion of part-time workers. Critical results for the two study groups are the relatively high job insecurity in nursing homes and the lack of social relations for the HCrs.</p

Protecting metal-organic framework crystals from hydrolytic degradation by spray-dry encapsulating them into polystyrene microspheres

A one-step, alternative, rapid, and scalable spray-drying (SD) synthesis of metal-organic frameworks (MOF)@polymer composites with enhanced hydrolytic stabilities was reported. SD was used to encapsulate preformed MOF crystals in a polymeric matrix to generate microscale MOF@polymer spheres. For proof-of-concept Hong-Kong University of Science and Technology-1 (HKUST-1) was chosen as the water-sensitive MOF, and polystyrene (PS) as the organic polymer. The synthesis of HKUST-1@PS began with preparation of a stable colloidal suspension of HKUST-1 crystals and a solution of PS in dichloromethane (DCM). This mixture was atomized using a two-fluid nozzle. After 40 min of continuous spraying, 1.7 g of a blue powder was recovered. The sample was then washed with ethanol and dried at 120°C under vacuum. This product was analyzed through field-emission scanning electron microscopy (FESEM), which indicated that it comprised smooth microspheres of HKUST-1@PS composites and did not contain any free HKUST-1. X-ray powder diffraction (XRPD) analysis of these spheres revealed a perfect match with the HKUST-1 pattern. The exclusive presence of microspheres and the match in XRPD patterns evidenced that HKUST-1 crystals were indeed entrapped within the polymeric matrix of PS

Metal-organic frameworks for water adsorption applications in the automotive filtration industry

In dieser Arbeit werden verschiedene MOF Materialien die sich für die Wasseradsorption eignen hinsichtlich Ihrer Wasseradsorptionseigenschaften untersucht. Das vielversprechendste Material wird ausgewählt und an einem Prüfstand für Lufttrocknerkartuschen untersucht. Für diese Messungen ist eine geeignete Formgebung des Pulvers von Nöten, welche eine wichtige Rolle in dieser Arbeit spielt. Das Material Cu3(BTC)2 wurde hier zu monolithischen Formkörpern verarbeitet. Eine weitere Art der Formgebung war das Pressen von Papieren sowie das direkte Kristallwachstum auf Zellulose Fasern. Desweiteren wurden die Materialien hinsichtlich der Trocknung von n-Heptan untersucht, was hier als Referenz für Dieselkraftstoffe herangezogen wurde. Die Analytik wurde mittels Karl-Fischer Titration duchgeführt. MOF Materialien wurden in beiden Fällen mit kommerziell verwendeten Zeolithen und Silikagel verglichen.Metal-organic frameworks (MOFs) were investigated for their possible use in drying of compressed air in air braking systems for commercial vehicles. Another possible application was the drying of diesel fuel. In this context, n-heptane was chosen as a reference for diesel fuel. Selected metal-organic frameworks were characterized regarding the water adsorption properties by recording water adsorption isotherms. The most promising material was further investigated on a air-drying cartridge test rig. In order to perform these tests, the powder had to be processed to monolithic structures, beads or paper sheets,i.e. a shape that is suitable for the given application. The MOF Cu3(BTC)2 was sucessfully extruded to monolithic structures, which were used in the test rig experiments. Another possibility for immobilization of Cu3(BTC)2 was the crystal growth on pulp fibers. N-heptane drying isotherms were measured on selected samples making use of Karl-Fischer coulometric titration. In both applications, MOF materials were compared with silica based desiccants