Influence of atmospheric turbulences on laser beam intensity profile

Optické bezkabelové spoje poskytují přirozenou alternativu k mikrovlnným a kabelovým systémům. Tato technologie je použita pro optické spoje mezi pozemními stanicemi a také mezi platformami ve vysokých výškách (HAPs). Hlavním cílem práce je ucelení poznatků o degradaci optického svazku v atmosféře. Optický svazek je v atmosférickém přenosovém prostředí vystavován jevům, které jej ovlivňují, např. fluktuace optické intenzity vlivem turbulencí, atmosférický útlum zapříčiněný absorpcí či rozptylem. Dále se práce zaobírá vznikem a působením atmosférických turbulencí na intenzitní profil laserového svazku a určením míry atmosférických turbulencí a jejich popisem.Free space optical communications provide a reliable alternative to microwave and cable system applications. This technology is utilized for an optical links between ground stations, and moreover for links between High Altitude Platforms (HAPs). The main goal of the project is to gather knowledge about degradation of an optical beam in the atmosphere. The optical beam is being exposed to many factors such as intensity fluctuation based on turbulence, attenuation due to absorption and scattering. Furthermore, an emergence and influence of the atmospheric turbulences on the intensity profile of the laser beam are discussed. At the end, the methods of atmospheric turbulence measurement are given.

LIDAR sensing of the atmosphere: application to CO2 detection

Znalost o prostorovém rozložení, koncentraci a zdrojích CO2 v atmosféře je klíčová k pochopení přírodního cyklu oxidu uhličitého, k předpovědi vývoje a vlivu CO2 na klimatické změny. Tato práce se zabývá problematikou optického dálkového snímání za použití LIDAR (Light Detection and Ranging) systému. Obsahuje potřebné teoretické znalosti o LIDAR systému, použití a principy. Z mnoha aplikací využívající LIDAR je v této práci nastíněno provedení a měření pomocí DIAL (Differential Absorption LIDAR) systému určeného k určení koncentrace CO2 v atmosféře, tak i využití dalších aktivních či pasivních způsobů snímání CO2.Knowledge of the spatial distribution, concentration and sources of atmospheric CO2 is a key factor for understanding of the carbon natural cycle, predicting evolution and the impact of carbon dioxide on climate changes. This work deals with optical remote sensing using LIDAR (Light Detection and Ranging). It contains necessary theoretical background of LIDAR system, the use and principles. LIDAR is used in many applications. The application, realization and measurement of concentration CO2 in the atmosphere with DIAL (Differential Absorption LIDAR) are outlined and also the use of other active and passive sensing techniques of CO2.

Nanoparticle-based rifampicin delivery system development

The alkaline milieu of chronic wounds severely impairs the therapeutic effect of antibiotics, such as rifampicin; as such, the development of new drugs, or the smart delivery of existing drugs, is required. Herein, two innovative polyelectrolyte nanoparticles (PENs), composed of an amphiphilic chitosan core and a polycationic shell, were synthesized at alkaline pH, and in vitro performances were assessed by H-1 NMR, elemental analysis, FT-IR, XRD, DSC, DLS, SEM, TEM, UV/Vis spectrophotometry, and HPLC. According to the results, the nanostructures exhibited different morphologies but similar physicochemical properties and release profiles. It was also hypothesized that the simultaneous use of the nanosystem and an antioxidant could be therapeutically beneficial. Therefore, the simultaneous effects of ascorbic acid and PENs were evaluated on the release profile and degradation of rifampicin, in which the results confirmed their synergistic protective effect at pH 8.5, as opposed to pH 7.4. Overall, this study highlighted the benefits of nanoparticulate development in the presence of antioxidants, at alkaline pH, as an efficient approach for decreasing rifampicin degradation.Ministry of Education, Youth and Sport of the Czech Republic-DKRVO [RP/CPS/2020/005

Composite based on PLA with improved shape stability under high-temperature conditions

Composite materials based on PLA have been studied in depth for many applications, including food packaging. This manuscript describes extensive research conducted on a biodegradable polymer (PLA), inorganic filler (CaCO3), and polyester-based plasticizer (PEP, based on a copolymer of low-molecular-weight PLA and PEG) prepared under semi-industrial conditions, as applicable for the packaging of hot food. The properties of the composite were achieved by post-processing annealing, notably its thermal stability, thereby permitting contact of the material with hot food. The manner of processing was deemed suitable for deployment at an industrial scale, moreover, the thermal stability of the final product endured, evidencing its applicability for such packaging. Change in the morphology of the structure of the composite material depended on the composition and annealing process, as detailed herein. The effect of the post-production thermal annealing on the molecular weight of samples was studied using the gel permeation chromatography. The thermal properties of the composites were investigated by differential scanning calorimetry, dynamic mechanical analysis, and thermogravimetric analysis. The crystallinity was assessed using X-ray diffraction technique, while mechanical behavior was tested in relation to the given tensile properties, shape stability at high temperature, and permeability by the transmission rates of gas/water vapor.Technology Agency of the Czech Republic, TACR: TH02020836; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: 8JPL19031, RP/CPS/2022/00

Structure-based design of charge-conversional drug self-delivery systems for better targeted cancer therapy

Various design and fabrication strategies of carrier-based drug delivery systems have been quickly established and applied for cancer therapy in recent years. These systems contribute greatly to current cancer treatments but further development needs to be made to eliminate obstacles such as low drug loading capacity and severe side effects. To achieve better drug delivery, we propose an innovative strategy for the construction of easy manufactured drug self-delivery systems based on molecular structures, which can be used for the co-delivery of curcuminoids and all the nitrogen-containing derivatives of camptothecin for better targeted cancer therapy with minimized side effects. The formation mechanism investigation demonstrates that the rigid planar structures of camptothecin derivatives and curcuminoids with relevant leaving hydrogens make it possible for them to be assembled into nanoparticles under suitable conditions. These nanoparticles show stabilized particle sizes (100 nm) under various conditions and tunable surface charges which increase from around −10 mV in a normal physiological condition (pH 7.4) to +40 mV under acidic tumor environments. In addition, in vivo mice experiments have demonstrated that, compared to irinotecan (a derivative of camptothecin) itself, the co-delivered irinotecan curcumin nanoparticles exhibited significantly enhanced lung and gallbladder targeting, improved macrophage-clearance escape and ameliorated colorectal cancer treatment with an eradication of life-threatening diarrhea, bringing hope for better targeted chemotherapy and clinical translation. Lastly, the strategy of structure based design of drug self-delivery systems may inspire more research and discoveries of similar self-delivered nano systems for wider pharmaceutical applications. © 2019 Elsevier LtdMinistry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LO 1504]; Internal Grant Agency of the Tomas Bata University in Zlin [IGA/CPS/2017/005, IGA/CPS/2018/003, IGA/CPS/2019/006]; Fund for Fostering Talents in Basic Science of the National Natural Science Foundation of ChinaNational Natural Science Foundation of China [J1310034-18]; Quantitative and Systems Biology program, University of California, Merced, United State

Nanoparticle-Based Rifampicin Delivery System Development

The alkaline milieu of chronic wounds severely impairs the therapeutic effect of antibiotics, such as rifampicin; as such, the development of new drugs, or the smart delivery of existing drugs, is required. Herein, two innovative polyelectrolyte nanoparticles (PENs), composed of an amphiphilic chitosan core and a polycationic shell, were synthesized at alkaline pH, and in vitro performances were assessed by 1H NMR, elemental analysis, FT-IR, XRD, DSC, DLS, SEM, TEM, UV/Vis spectrophotometry, and HPLC. According to the results, the nanostructures exhibited different morphologies but similar physicochemical properties and release profiles. It was also hypothesized that the simultaneous use of the nanosystem and an antioxidant could be therapeutically beneficial. Therefore, the simultaneous effects of ascorbic acid and PENs were evaluated on the release profile and degradation of rifampicin, in which the results confirmed their synergistic protective effect at pH 8.5, as opposed to pH 7.4. Overall, this study highlighted the benefits of nanoparticulate development in the presence of antioxidants, at alkaline pH, as an efficient approach for decreasing rifampicin degradation