12 research outputs found
Phase Randomness in a Semiconductor Laser: the Issue of Quantum Random Number Generation
Gain-switched lasers are in demand in numerous quantum applications,
particularly, in systems of quantum key distribution and in various optical
quantum random number generators. The reason for this popularity is natural
phase randomization between gain-switched laser pulses. The idea of such
randomization has become so familiar that most authors use it without regard to
the features of the laser operation mode they use. However, at high repetition
rates of laser pulses or when pulses are generated at a bias current close to
the threshold, the phase randomization condition may be violated. This paper
describes theoretical and experimental methods for estimating the degree of
phase randomization in a gain-switched laser. We consider in detail different
situations of laser pulse interference and show that the interference signal
remains quantum in nature even in the presence of classical phase drift in the
interferometer provided that the phase diffusion in a laser is efficient
enough. Moreover, we formulate the relationship between the previously
introduced quantum reduction factor and the leftover hash lemma. Using this
relationship, we develop a method to estimate the quantum noise contribution to
the interference signal in the presence of phase correlations. Finally, we
introduce a simple experimental method based on the analysis of statistical
interference fringes, providing more detailed information about the
probabilistic properties of laser pulse interference
How does renewable energy consumption affect economic growth? Evidence from the European Union countries
Research background: Fossil fuels are used at such a high rate that they are currently being depleted. Moreover, they are associated with a greenhouse effect leading to global warming. Meanwhile, green energy is naturally replenished and fosters sustainable development (Nelson and Starcher, 2015). However, the empirical evidence of the impact of green energy on economic growth is controversial (Adewuyi and Awodumi, 2017; Chen et al., 2020; Destek and Aslan, 2017; Zafar et al., 2018).
Purpose of the article: This paper analyses the impact of renewable energy consumption on economic growth in the European Union (EU) countries. This is important in line with the goals of EU to shift towards green energy during the coming years (Directive (EU) 2018/2001).
Methods: We use data of the World Bank and Our World in Data over 1990 to 2015 for 28 EU countries. We estimate the impact of renewable energy consumption on the countriesâ gross domestic product. The control variables are labor force, research and development, and foreign direct investment. We apply the pooled mean group, mean group, the dynamic fixed effect estimators (Pesaran, 1997; Pesaran et al., 1999), and generalized method of moments (Arellano & Bond, 1991).
Findings & Value added: Results show that the renewable energy consumption positively affects economic growth of the EU countries. We contribute by shedding light on the possibility to develop renewable energy, while achieving economic growth. The results have important implications for economic policy
An Integrated Approach for Formation Micro-Image Rock Typing Based on Petrography Data: A Case Study in Shallow Marine Carbonates
Synthesis of Novel Lipophilic Polyamines via Ugi Reaction and Evaluation of Their Anticancer Activity
Natural polyamines (PAs) are involved in the processes of proliferation and differentiation of cancer cells. Lipophilic synthetic polyamines (LPAs) induce the cell death of various cancer cell lines. In the current paper, we have demonstrated a new method for synthesis of LPAs via the multicomponent Ugi reaction and subsequent reduction of amide groups by PhSiH3. The anticancer activity of the obtained compounds was evaluated in the A-549, MCF7, and HCT116 cancer cell lines. For the first time, it was shown that the anticancer activity of LPAs with piperazine fragments is comparable with that of aliphatic LPAs. The presence of a diglyceride fragment in the structure of LPAs appears to be a key factor for the manifestation of high anticancer activity. The findings of the study strongly support further research in the field of LPAs and their derivatives
Air-Filled Bubbles Stabilized by Gold Nanoparticle/Photodynamic Dye Hybrid Structures for Theranostics
Microbubbles have already reached clinical practice as ultrasound contrast agents for angiography. However, modification of the bubblesâ shell is needed to produce probes for ultrasound and multimodal (fluorescence/photoacoustic) imaging methods in combination with theranostics (diagnostics and therapeutics). In the present work, hybrid structures based on microbubbles with an air core and a shell composed of bovine serum albumin, albumin-coated gold nanoparticles, and clinically available photodynamic dyes (zinc phthalocyanine, indocyanine green) were shown to achieve multimodal imaging for potential applications in photodynamic therapy. Microbubbles with an average size of 1.5 ± 0.3 ÎŒm and concentration up to 1.2 Ă 109 microbubbles/mL were obtained and characterized. The introduction of the dye into the system reduced the solutionâs surface tension, leading to an increase in the concentration and stability of bubbles. The combination of gold nanoparticles and photodynamic dyesâ influence on the fluorescent signal and probesâ stability is described. The potential use of the obtained probes in biomedical applications was evaluated using fluorescence tomography, raster-scanning optoacoustic microscopy and ultrasound response measurements using a medical ultrasound device at the frequency of 33 MHz. The results demonstrate the impact of microbubblesâ stabilization using gold nanoparticle/photodynamic dye hybrid structures to achieve probe applications in theranostics
Plasmonic Nanopowders for Photothermal Therapy of Tumors
We describe a novel strategy for the fabrication of plasmonic
nanopowders
(dried gold nanoparticles) by using wet chemical nanoparticle synthesis,
PEG-SH functionalization, and a standard freeze-drying technique.
Our strategy is illustrated by successful fabrication of different
plasmonic nanopowders, including gold nanorods, goldâsilver
nanocages, and gold nanospheres. Importantly, the dried nanoparticles
can be stored for a long time under usual conditions and then can
easily be dissolved in water at a desired concentration without such
hard manipulations as sonication or heating. Redispersed samples maintain
the plasmonic properties of parent colloids and do not form aggregates.
These properties make pegylated freeze-dried gold nanoparticles attractive
candidates for plasmonic photothermal therapy in clinical settings.
In this work, redispersed gold nanorods were intravenously administered
to mice bearing Ehrlich carcinoma tumors at doses of 2 and 8 mg (Au)/kg
(animal). Particle biodistribution was measured by atomic absorption
spectroscopy, and tumor hyperthermia effects were studied under laser
NIR irradiation. Significant tumor damage was observed only at the
higher dose of the nanorods
Plasmonic Nanopowders for Photothermal Therapy of Tumors
We describe a novel strategy for the fabrication of plasmonic
nanopowders
(dried gold nanoparticles) by using wet chemical nanoparticle synthesis,
PEG-SH functionalization, and a standard freeze-drying technique.
Our strategy is illustrated by successful fabrication of different
plasmonic nanopowders, including gold nanorods, goldâsilver
nanocages, and gold nanospheres. Importantly, the dried nanoparticles
can be stored for a long time under usual conditions and then can
easily be dissolved in water at a desired concentration without such
hard manipulations as sonication or heating. Redispersed samples maintain
the plasmonic properties of parent colloids and do not form aggregates.
These properties make pegylated freeze-dried gold nanoparticles attractive
candidates for plasmonic photothermal therapy in clinical settings.
In this work, redispersed gold nanorods were intravenously administered
to mice bearing Ehrlich carcinoma tumors at doses of 2 and 8 mg (Au)/kg
(animal). Particle biodistribution was measured by atomic absorption
spectroscopy, and tumor hyperthermia effects were studied under laser
NIR irradiation. Significant tumor damage was observed only at the
higher dose of the nanorods
Hematopoietic Disorders, Renal Impairment and Growth in Mucopolysaccharidosis-Plus Syndrome
Mucopolysaccharidoses (MPS) are rare lysosomal storage disorders (LSD) characterized by the excessive accumulation of glycosaminoglycans (GAG). Conventional MPS, caused by inborn deficiencies of lysosomal enzymes involved in GAG degradation, display various multisystemic symptomsâincluding progressive neurological complications, ophthalmological disorders, hearing loss, gastrointestinal and hepatobiliary issues, cardiorespiratory problems, bone and joint abnormalities, dwarfism, and coarse facial features. Mucopolysaccharidosis-Plus Syndrome (MPSPS), an autosomal recessive disease caused by a mutation in the endo-lysosomal tethering protein VPS33A, shows additional renal and hematopoietic abnormalities (âPlus symptomsâ) uncommon in conventional MPS. Here, we analyze data from biochemical, histological, and physical examinationsâparticularly of blood counts and kidney functionâto further characterize the clinical phenotype of MPSPS. A series of blood tests indicate hematopoietic symptoms including progressive anemia and thrombocytopenia, which correlate with histological observations of hypoplastic bone marrow. High urinary excretion of protein (caused by impairments in renal filtration), hypoalbuminemia, and elevated levels of creatinine, cholesterol, and uric acid indicate renal dysfunction. Histological analyses of MPSPS kidneys similarly suggest the extensive destruction of glomerular structures by foamy podocytes. Height and weight did not significantly deviate from the average, but in some cases, growth began to decline at around six months or one year of age