255 research outputs found

    Integrated Sensors to Experimentally Measure Microheater Uniformity: Geometry Implications in Meander-Based Structures

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    This work was supported by the Research Foundation Flanders (FWO Vlaanderen) for funding in the research project under Grant G087422N

    Optical Detection of Volatile Organic Compounds: A Review of Methods and Functionalized Sensing Materials

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    With growing awareness of the detrimental effects of volatile organic compounds (VOCs) on human health and their potential in disease screening, the demand for effective detection methods has surged. Optical detectors are highly desirable because of their excellent versatility, fast response time, and suitability for remote detection. This review aims to analyze various optical sensors for VOC detection, focusing on the functionalizing materials used in different optical transducers. The review is organized into six sections, each covering a different sensor category based on the type of optical phenomenon utilized for VOC detection: diffraction, interference, polarization change, optical resonance, absorption, and evanescent wave propagation. Achievable sensitivities, limitations, and advantages of each approach are discussed, providing valuable insights for the development of advanced VOC detection technologies

    Mechanical properties of electrochemically synthesised metal-organic framework thin films

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    We investigated the mechanical properties of metal-organic framework thin-film coatings grown by an electrochemical method, which allows fast deposition in environmentally friendly solvents. For the first time, Cu(CHDA) and Cu(INA)2 are electrochemically synthesised as dense coatings on Cu-electrodes, alongside the well-known Cu3(BTC)2 (CHDA = trans-cyclohexane-1,4-dicarboxylate; INA = isonicotinate; BTC = benzene-1,3,5-tricarboxylate). In order to probe the mechanical behaviour of the MOF coatings, both nanoindentation and nanoscratch experiments are performed. The indentation of a polycrystalline film allows the determination of average Young's moduli and hardness of the coatings. Cu(CHDA) exhibits the highest stiffness and hardness, with values of 10.9 GPa and 0.46 GPa, respectively. Intermediate values are obtained for the well-known Cu3(BTC) 2 and the smallest values for Cu(INA)2. A close inspection of the crystal lattice of the MOF materials under investigation allows for correlating the mechanical properties and structural building units of these materials. Finally, the effect of the fundamental mechanical properties of MOF films on their scratch and wear resistance is illustrated

    Influence of Precursor Density and Conversion Time on the Orientation of Vapor-Deposited ZIF-8

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    ZIF-8 was synthesized by subjecting ZnO thin films deposited via plasma-enhanced atomic layer deposition to a 2-methylimidazole vapor. The impact of the conversion time as well as the density and thickness of the ZnO precursor on the resulting ZIF-8 layers were investigated. Grazing Incidence X-ray diffraction reveals a preferred (100) or (111) orientation of the ZIF-8 crystals, depending on thickness and density of the precursor, and with a more prominent orientation at longer conversion times. The onset of crystallization occurs after 20 min of conversion for the less dense precursor, compared to 40 min for the denser one. The ZIF-8 thickness and roughness increase with conversion time. The final thickness of the ZIF-8 layer depends on the thickness and density of the precursor layer, and can be up to 15-fold higher than the precursor thickness

    Aqueous Flow Reactor and Vapour-Assisted Synthesis of Aluminium Dicarboxylate Metal-Organic Frameworks with Tuneable Water Sorption Properties

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    Energy-efficient indoors temperature and humidity control can be realised by using the reversible adsorption and desorption of water in porous materials. Stable microporous aluminium-based metal-organic frameworks (MOFs) present promising water sorption properties for this goal. The development of synthesis routes that make use of available and affordable building blocks and avoid the use of organic solvents is crucial to advance this field. In this work, two scalable synthesis routes under mild reaction conditions were developed for aluminium-based MOFs: (1) in aqueous solutions using a continuous-flow reactor and (2) through the vapour-assisted conversion of solid precursors. Fumaric acid, its methylated analogue mesaconic acid, as well as mixtures of the two were used as linkers to obtain polymorph materials with tuneable water sorption properties. The synthesis conditions determine the crystal structure and either the MIL-53 or MIL-68 type structure with square-grid or kagome-grid topology, respectively, is formed. Fine-tuning resulted in new MOF materials thus far inaccessible through conventional synthesis routes. Furthermore, by varying the linker ratio, the water sorption properties can be continuously adjusted while retaining the sigmoidal isotherm shape advantageous for heat transformation and room climatisation applications

    Integrated cleanroom process for the vapor-phase deposition of large-area zeolitic imidazolate framework thin films

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    Robust and scalable thin-film deposition methods are key to realize the potential of metal-organic frameworks (MOFs) in electronic devices. Here, we report the first integration of the chemical vapor deposition (CVD) of MOF coatings in a custom reactor within a cleanroom setting. As a test case, the MOF-CVD conditions for the zeolitic imidazolate framework-8 are optimized to enable smooth, pinhole-free, and uniform thin films on full 200 mm wafers under mild conditions. The single-chamber MOF-CVD process and the impact of the deposition parameters are elucidated via a combination of in situ monitoring and ex situ characterization. The resulting process guidelines will pave the way for new MOF-CVD formulations and a plethora of MOF-based devices

    Higher versus lower mean arterial blood pressure after cardiac arrest and resuscitation (MAP-CARE): A protocol for a randomized clinical trial.

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    peer reviewed[en] BACKGROUND: In patients resuscitated after cardiac arrest, a higher mean arterial pressure (MAP) may increase cerebral perfusion and attenuate hypoxic brain injury. Here we present the protocol of the mean arterial pressure after cardiac arrest and resuscitation (MAP-CARE) trial aiming to investigate the influence of MAP targets on patient outcomes. METHODS: MAP-CARE is one component of the Sedation, Temperature and Pressure after Cardiac Arrest and Resuscitation (STEPCARE) 2 x 2 x 2 factorial randomized trial. The MAP-CARE trial is an international, multicenter, parallel-group, investigator-initiated, superiority trial designed to test the hypothesis that targeting a higher (>85 mmHg) (intervention) versus a lower (>65 mmHg) (comparator) MAP after resuscitation from cardiac arrest reduces 6-month mortality (primary outcome). Trial participants are adults with sustained return of spontaneous circulation who are comatose following resuscitation from out-of-hospital cardiac arrest. The two other components of the STEPCARE trial evaluate sedation and temperature control strategies. Apart from the STEPCARE trial interventions, all other aspects of general intensive care will be according to the local practices of the participating site. Neurological prognostication will be performed according to European Resuscitation Council and European Society of Intensive Care Medicine guidelines by a physician blinded to allocation group. The sample size of 3500 participants provides 90% power with an alpha of 0.05 to detect a 5.6 absolute risk reduction in 6-month mortality, assuming a mortality of 60% in the control group. Secondary outcomes will be poor functional outcome 6 months after randomization, patient-reported overall health 6 months after randomization, and the proportion of participants with predefined severe adverse events. CONCLUSION: The MAP-CARE trial will investigate if targeting a higher MAP compared to a lower MAP during intensive care of adults who are comatose following resuscitation from out-of-hospital cardiac arrest reduces 6-month mortality

    Continuous deep sedation versus minimal sedation after cardiac arrest and resuscitation (SED-CARE): A protocol for a randomized clinical trial.

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    peer reviewed[en] BACKGROUND: Sedation is often provided to resuscitated out-of-hospital cardiac arrest (OHCA) patients to tolerate post-cardiac arrest care, including temperature management. However, the evidence of benefit or harm from routinely administered deep sedation after cardiac arrest is limited. The aim of this trial is to investigate the effects of continuous deep sedation compared to minimal sedation on patient-important outcomes in resuscitated OHCA patients in a large clinical trial. METHODS: The SED-CARE trial is part of the 2 × 2 × 2 factorial Sedation, Temperature and Pressure after Cardiac Arrest and Resuscitation (STEPCARE) trial, a randomized international, multicentre, parallel-group, investigator-initiated, superiority trial with three simultaneous intervention arms. In the SED-CARE trial, adults with sustained return of spontaneous circulation (ROSC) who are comatose following resuscitation from OHCA will be randomized within 4 hours to continuous deep sedation (Richmond agitation and sedation scale (RASS) -4/-5) (intervention) or minimal sedation (RASS 0 to -2) (comparator), for 36 h after ROSC. The primary outcome will be all-cause mortality at 6 months after randomization. The two other components of the STEPCARE trial evaluate sedation and temperature control strategies. Apart from the STEPCARE trial interventions, all other aspects of general intensive care will be according to the local practices of the participating site. Neurological prognostication will be performed according to European Resuscitation Council and European Society of Intensive Care Medicine guidelines by a physician blinded to the allocation group. To detect an absolute risk reduction of 5.6% with an alpha of 0.05, 90% power, 3500 participants will be enrolled. The secondary outcomes will be the proportion of participants with poor functional outcomes 6 months after randomization, serious adverse events in the intensive care unit, and patient-reported overall health status 6 months after randomization. CONCLUSION: The SED-CARE trial will investigate if continuous deep sedation (RASS -4/-5) for 36 h confers a mortality benefit compared to minimal sedation (RASS 0 to -2) after cardiac arrest
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