Energy efficiency and living comfort certainly contribute to popularity of the passive house concept. Since these houses are weakly coupled to an environment, any internal energy gains are difficult ...to be released against small temperature gradients, i.e. in a typical situation occurring in hot summer months. In such a case already a small energy input raises the internal temperature significantly and dramatically affects the living comfort. To provide more information on this problem, we collected and analyzed data from a single family Slovenian passive house. Our goal was to estimate the general house response under real conditions and to investigate overheating in hot summer periods. Different energy gains were identified and explored with respect to their influence on the overheating of this passive house. Results show that windows-opening during the nights in hot summer days, strict shading of the southern and western windows as well as minimization of internal energy sources are necessary and sufficient to keep internal temperature on the comfort level.
In recent decades many studies have focused on the thermal performance of massive and lightweight constructions of energy-efficient houses. Surprisingly, temperature and humidity profiles have been ...addressed relatively rarely, despite the fact that they can influence the living conditions, the lifetime of the construction materials, as well as the energy efficiency of the house and consequently the environment as well. In the present study we compare different lightweight building blocks and the associated temperature and relative-humidity profiles. The studies were performed on residential as well as test passive houses. Small differences in the building blocks were identified as having a large influence on the performance of the building. The structural elements should be placed in such a way as to prevent shear forces due to humidity differences. It has been proven that ventilated wooden facades, in comparison with classical façade plaster, protect the building blocks from high thermal loads. Last but not least, the use of vapor barriers instead of vapor retarders and a lack of moisture-buffering materials led to a higher indoor relative humidity, as well as higher moisture loads on construction that could have an impact on the durability of a building and also on the energy performance of the house.
► Choice of building materials and building blocks influences living conditions. ► Vapor retarders and moisture-buffering materials maintain indoor comfort. ► Building blocks can be designed in a way to prevent large humidity differences. ► Ventilated wooden facades protect building blocks from high thermal loads.
Nanomaterial (NM) characteristics may affect the pulmonary toxicity and inflammatory response, including specific surface area, size, shape, crystal phase or other surface characteristics. Grouping ...of TiO2 in hazard assessment might be challenging because of variation in physicochemical properties. We exposed C57BL/6 J mice to a single dose of four anatase TiO2 NMs with various sizes and shapes by intratracheal instillation and assessed the pulmonary toxicity 1, 3, 28, 90 or 180 days post-exposure. The quartz DQ12 was included as benchmark particle. Pulmonary responses were evaluated by histopathology, electron microscopy, bronchoalveolar lavage (BAL) fluid cell composition and acute phase response. Genotoxicity was evaluated by DNA strand break levels in BAL cells, lung and liver in the comet assay. Multiple regression analyses were applied to identify specific TiO2 NMs properties important for the pulmonary inflammation and acute phase response. The TiO2 NMs induced similar inflammatory responses when surface area was used as dose metrics, although inflammatory and acute phase response was greatest and more persistent for the TiO2 tube. Similar histopathological changes were observed for the TiO2 tube and DQ12 including pulmonary alveolar proteinosis indicating profound effects related to the tube shape. Comparison with previously published data on rutile TiO2 NMs indicated that rutile TiO2 NMs were more inflammogenic in terms of neutrophil influx than anatase TiO2 NMs when normalized to total deposited surface area. Overall, the results suggest that specific surface area, crystal phase and shape of TiO2 NMs are important predictors for the observed pulmonary effects of TiO2 NMs.
•Inflammation and acute phase response was highest and more persistent for TiO2 tube.•TiO2 tube and DQ12 caused pulmonary alveolar proteinosis.•Rutile TiO2 NMs were more inflammogenic in terms of neutrophil influx than anatase.•BET surface area strongly correlated with neutrophil influx for both crystal phases.•BET surface area, crystal phase and shape of TiO2 NMs are predictors for the effects.
Understanding the cell–biomaterial interface from the very first contact is of crucial importance for their successful implementation and function in damaged tissues. However, the lack of bio- and ...mechano-analytical methods to investigate and probe the initial processes on the interface, especially in 3D, raises the need for applying new experimental techniques. In our study, optical tweezers combined with confocal fluorescence microscopy were optimized to investigate the initial cell–scaffold contact and to investigate its correlation with the material-dependent cell growth. By the optical tweezers-induced cell manipulation accompanied by force detection up to 100 pN and position detection by fluorescence microscopy, accurate adhesion dynamics and strength analysis was implemented, where several attachment sites were formed on the interface in the first few seconds. More importantly, we have shown that dynamics of cell adhesion on scaffold surfaces correlates with cell growth on the days scale, which indicates that the first seconds of the contact could markedly direct further cell response. Such a contact dynamics analysis on 3D scaffold surfaces, applied for the first time, can thus serve to predict scaffold biocompatibility.
We studied the influence of sodium and calcium chloride on the global and local membrane properties of fluid palmitoyl-oleoyl phosphatidylcholine bilayers, applying synchrotron small-angle x-ray ...diffraction, spin-labeling electron paramagnetic resonance spectroscopy, and differential scanning calorimetry, as well as simultaneous density and acoustic measurements. The salt concentration was varied over a wide range from 0 to 5
M. We found that NaCl leads to a continuous swelling of the bilayers, whereas the behavior of the bilayer separation
d
W in the presence of CaCl
2 is more complex, showing an initial large
d
W value, which decreased upon further addition of salt and finally increased again in the high concentration regime. This can be understood by a change of balance between electrostatic and van der Waals interactions. We were further able to show that both salts lead to a significant increase of order within the lipid bilayer, leading to a decrease of bilayer elasticity and shift of main phase transition temperature. This effect is more pronounced for Ca
2+, and occurs mainly in the high salt-concentration regime. Thus, we were able to reconcile previous controversies between molecular dynamics simulations and x-ray diffraction experiments regarding the effect of salts on neutral lipid bilayers.
Generating activatable probes that report about molecular vicinity through contact-based mechanisms such as aggregation can be very convenient. Specifically, such probes change a particular spectral ...property only at the intended biologically relevant target. Xanthene derivatives, for example rhodamines, are able to form aggregates. It is typical to examine aggregation by absorption spectroscopy but for microscopy applications utilizing fluorescent probes it is very important to perform characterization by measuring fluorescence spectra. First we show that excitation spectra of aqueous solutions of rhodamine 6G can be very informative about the aggregation features. Next we establish the dependence of the fluorescence emission spectral maximum shift on the dimer concentration. The obtained information helped us confirm the possibility of aggregation of a recently designed and synthesized rhodamine 6G-based pH-activatable fluorescent probe and to study its pH and concentration dependence. The size of the aggregation-induced emission spectral shift at specific position on the sample can be measured by fluorescence microspectroscopy, which at particular pH allows estimation of the local concentration of the observed probe at microscopic level. Therefore, we show that besides aggregation-caused quenching and aggregation-induced emission also aggregation-induced emission spectral shift can be a useful photophysical phenomenon.
Display omitted
•Rhodamine aggregation in aqueous solutions was studied by fluorescence.•The effect of aggregation on excitation and emission spectra was determined.•Dependence of the emission red-shift on concentration was quantified.•pH dependence of the shift for a probe internalized in cells was explained.•Imaging application of aggregation-induced emission spectral shift was showed.
Legionella pneumophila can cause a potentially fatal form of humane pneumonia (Legionnaires' disease), which is most problematic in immunocompromised and in elderly people. Legionella species is ...present at low concentrations in soil, natural and artificial aquatic systems and is therefore constantly entering man-made water systems. The environment temperature for it's ideal growth range is between 32 and 42°C, thus hot water pipes represent ideal environment for spread of Legionella. The bacteria are dormant below 20°C and do not survive above 60°C. The primary method used to control the risk from Legionella is therefore water temperature control. There are several other effective treatments to prevent growth of Legionella in water systems, however current disinfection methods can be applied only intermittently thus allowing Legionella to grow in between treatments. Here we present an alternative disinfection method based on antibacterial coatings with Cu-TiO2 nanotubes deposited on preformed surfaces. In the experiment the microbiocidal efficiency of submicron coatings on polystyrene to the bacterium of the genus Legionella pneumophila with a potential use in a water supply system was tested. The treatment thus constantly prevents growth of Legionella pneumophila in presence of water at room temperature. Here we show that 24-hour illumination with low power UVA light source (15 W/m2 UVA illumination) of copper doped TiO2 nanotube coated surfaces is effective in preventing growth of Legionella pneumophila. Microbiocidal effects of Cu-TiO2 nanotube coatings were dependent on the flow of the medium and the intensity of UV-A light. It was determined that tested submicron coatings have microbiocidal effects specially in a non-flow or low-flow conditions, as in higher flow rates, probably to a greater possibility of Legionella pneumophila sedimentation on the coated polystyrene surfaces, meanwhile no significant differences among bacteria reduction was noted regarding to non or low flow of medium.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
It is important to understand the nanomaterials intracellular trafficking and distribution and investigate their targeting into the nuclear area in the living cells. In our previous study, we firstly ...observed penetration of nonmodified positively charged carbon dots decorated with quaternary ammonium groups (QCDs) into the nucleus of mouse NIH/3T3 fibroblasts. Thus, in this work, we focused on deeper study of QCDs distribution inside two healthy mouse NIH/3T3 and L929 cell lines by fluorescence microspectroscopy and performed a comprehensive cytotoxic and DNA damage measurements. Real-time penetration of QCDs across the plasma cell membrane was recorded, concentration dependent uptake was determined and endocytic pathways were characterized. We found out that the QCDs concentration of 200 µg/mL is close to saturation and subsequently, NIH/3T3 had a different cell cycle profile, however, no significant changes in viability (not even in the case with QCDs in the nuclei) and DNA damage. In the case of L929, the presence of QCDs in the nucleus evoked a cellular death. Intranuclear environment of NIH/3T3 cells affected fluorescent properties of QCDs and evoked fluorescence blue shifts. Studying the intracellular interactions with CDs is essential for development of future applications such as DNA sensing, because CDs as DNA probes have not yet been developed.
To avoid a devastating effect of eye vision impairment on the information flow from the eye to our brain, enormous effort is being put during the last decades into the development of more sensitive ...diagnostics and more efficient therapies of retinal tissue. While morphology can be impressively imaged by optical coherence tomography, molecular-associated pathology information can be provided almost exclusively by auto-fluorescence-based methods. Among the latter, the recently developed fluorescence lifetime imaging ophthalmoscopy (FLIO) has the potential to provide both structural information and interacting pictures at the same time. The requirements for FLIO laser sources are almost orthogonal to the laser sources used in phototherapy that is expected to follow up the FLIO diagnostics. To make theranostics more effective and cheaper, the complete system would need to couple at least the modalities of low-power high-repetition-rate FLIO and precision high-pulse energy-adjustable repetition rate phototherapy. In addition, the intermediate-power high repetition rate for two-photon excitation would also be desired to increase the depth resolution. In our work, compact fiber-laser based on high-speed gain-switched laser diode has been shown to achieve adaptable/independently tunable repetition rate and energy per pulse allowing coupled fluorescence lifetime diagnostics via two-photon excitation and phototherapy via laser-induced photodisruption on a local molecular environment in a complex ex vivo retinal tissue.
Knowing the temperature distribution within the conducting walls of various multilayer-type materials is crucial for a better understanding of heat-transfer processes. This applies to many ...engineering fields, good examples being photovoltaics and microelectronics. In this work we present a novel fluorescence technique that makes possible the non-invasive imaging of local temperature distributions within a transparent, temperature-sensitive, co-doped Er:GPF1Yb0.5Er glass-ceramic with micrometer spatial resolution. The thermal imaging was performed with a high-resolution fluorescence microscopy system, measuring different focal planes along the
-axis. This ultimately enabled a precise axial reconstruction of the temperature distribution across a 500-µm-thick glass-ceramic sample. The experimental measurements showed good agreement with computer-modeled heat simulations and suggest that the technique could be adopted for the spatial analyses of local thermal processes within optically transparent materials. For instance, the technique could be used to measure the temperature distribution of intermediate, transparent layers of novel ultra-high-efficiency solar cells at the micron and sub-micron levels.
PDF
