Search results for " alchemy"
showing 10 items of 16 documents
Temperature Dependent Suns-V<inf>oc</inf> of Multicrystalline Silicon Solar Cells from Different Ingot Positions
2018
This paper presents temperature dependent Suns- Voc measurements on multicrystalline silicon cells originating from different ingot positions. The effective lifetime is found to increase for all cells when the temperature is increased from 25°C to 6°C. However, cells from the top of the ingot show a considerably larger increas 40–50% for illumination conditions of 0.1-1 Sun, compared to an increase of 20-30% observed for cells from the bottom. The decrease in Voc with increasing temperature is found to be lower for cells from the top of the ingot compared to cells from the bottom. The temperature coefficient of the Voc is found to vary 5% along the ingot at 1 Sun, highlighting the influence…
Photocrosslinked Dextran-Based Hydrogels as Carrier System for the Cells and Cytokines Induce Bone Regeneration in Critical Size Defects in Mice
2018
Modified biomaterials have for years been the focus of research into establishing new bone substitutes. In our preceding in vitro study employing different cell cultures, we developed chemically and mechanically characterized hydrogels based on photocrosslinkable dextran derivatives and demonstrated their cytocompatibility and their beneficial effects on the proliferation of osteoblasts and endothelial cells. In the present in vivo study, we investigate photocrosslinked dextran-based hydrogels in critical size defects in mice to evaluate their potential as carrier systems for cells or for a specific angiogenesis enhancing cytokine to induce bone formation. We could demonstrate that, with op…
WASTE DUMPS IN LATVIA: FORMER LANDFILLING, CONSEQUENCES AND POSSIBLE RECULTIVATION
2012
Particular attention in this article is paid to the research of two waste dumps in the capital city of Latvia – Riga, which are planned to be re-cultivated in the nearest future and one site, which is former toxic hazardous soil dump site, where the remediation of site is of priority need. The present study is giving a general overview of contamination level in two waste dumps in Riga, which were made in the period from 50-ties to 70-ties of the 20th century, also the case of hazardous soil dump site formed in a period of more than 100 years is described. Planned actions as well as direct remediational technologies to reduce the poisonous impact to the urban environment and the role of re-c…
Functionalized Poly(N-isopropylacrylamide)-Based Microgels in Tumor Targeting and Drug Delivery
2021
Over the past several decades, the development of engineered small particles as targeted and drug delivery systems (TDDS) has received great attention thanks to the possibility to overcome the limitations of classical cancer chemotherapy, including targeting incapability, nonspecific action and, consequently, systemic toxicity. Thus, this research aims at using a novel design of Poly(N-isopropylacrylamide) p(NIPAM)-based microgels to specifically target cancer cells and avoid the healthy ones, which is expected to decrease or eliminate the side effects of chemotherapeutic drugs. Smart NIPAM-based microgels were functionalized with acrylic acid and coupled to folic acid (FA), targeting the f…
Poly(N-isopropylacrylamide) and Copolymers: A Review on Recent Progresses in Biomedical Applications.
2017
The innate ability of poly(N-isopropylacrylamide) (PNIPAAm) thermo-responsive hydrogel to copolymerize and to graft synthetic polymers and biomolecules, in conjunction with the highly controlled methods of radical polymerization which are now available, have expedited the widespread number of papers published in the last decade—especially in the biomedical field. Therefore, PNIPAAm-based hydrogels are extensively investigated for applications on the controlled delivery of active molecules, in self-healing materials, tissue engineering, regenerative medicine, or in the smart encapsulation of cells. The most promising polymers for biodegradability enhancement of PNIPAAm hydrogels are probably…
Physicochemical and Rheological Characterization of Different Low Molecular Weight Gellan Gum Products and Derived Ionotropic Crosslinked Hydrogels
2021
A series of four different low molecular weight gellan gum products was obtained by alkaline hydrolysis with the aim to investigate the impact of the molecular weight on the rheological properties of the polysaccharide aqueous dispersions and on the physicochemical characteristics of derived ionotropic crosslinked hydrogels. In particular, thermo-rheological analysis was conducted on aqueous dispersions to study the influence of molecular weight on the thermogelation properties typical of the native polysaccharide while strain sweep experiments were conducted to establish if aqueous dispersion shows a viscoelastic behavior. The effect of different Ca2+ on the rheological properties of hydro…
Caffeine as a Gelator
2016
Caffeine (a stimulant) and ethanol (a depressant) may have opposite effects in our body, but under in vitro conditions they can “gel” together. Caffeine, being one of the widely used stimulants, continued to surprise the scientific community with its unprecedented biological, medicinal and physicochemical properties. Here, we disclose the supramolecular self-assembly of anhydrous caffeine in a series of alcoholic and aromatic solvents, rendering a highly entangled microcrystalline network facilitating the encapsulation of the solvents as illustrated using direct imaging, microscopy analysis and NMR studies. Peer reviewed
1.6 suns at 58&#x00B0;20&#x2032;N - the solar resource in Southern Norway
2014
We measured an extreme overirradiance event of 1.6 suns at latitude 58°20′N during a solar resource assessment in southern Norway. The burst occurred when the sun showed in a narrow gap between broken, optically thin altocumulus clouds. The enhancement was most intense within 3° around the solar disk. The annual solar irradiation in the plane of an optimally tilted PV array peaked at 1.30 MWh/m2 in the year 2013, and measured 1.20 MWh/m2 in the previous two years. These values exclude irradiance below 0.05 suns but include reflections from the sea surface and terrain which have not been quantified. The long-term average predicted by the Photovoltaic Geographical Information System (PVGIS) i…
Direct sunlight facility for testing and research in HCPV
2014
A facility for testing different components for HCPV application has been developed in the framework of "Fotovoltaico ad Alta Efficienza" (FAE) project funded by the Sicilian Regional Authority (PO FESR Sicilia 2007/2013 4.1.1.1). The testing facility is equipped with an heliostat providing a wide solar beam inside the lab, an optical bench for mounting and aligning the HCPV components, electronic equipments to characterize the I-V curves of multijunction cells operated up to 2000 suns, a system to circulate a fluid in the heat sink at controlled temperature and flow-rate, a data logging system with sensors to measure temperatures in several locations and fluid pressures at the inlet and ou…
Optimal temporal resolution for detailed studies of cloud-enhanced sunlight (Overirradiance)
2013
Enhancement of sunlight by clouds can lead to irradiance peaks much exceeding the extraterrestrial levels - close to 2 suns near the Equator and at least 1.5 suns at latitudes of about 60°. Some extreme overirradiance events can last many minutes, but durations in the order of 1 second are also possible. The present paper reports the shortest bursts recorded in Southern Norway in the years 2012 and 2013. Our records of 10-millisecond resolution from 2012 show that the optimal instantaneous irradiance sampling interval is less than 0.15 s at the present test site, while the optimal averaging time is less than 0.13 s. We propose simple equations for deriving these times in an arbitrary geogra…