Aggregated Form Research Articles

Chemical gas sensor, surface enhanced Raman scattering and photoelectrics of composite Langmuir-Blodgett films consisting of polypeptide and dye molecules

Langmuir-Blodgett (LB) technology has attracted increasing interest to generate intelligent biomaterials combined with novel peptide molecules. In this work, the composite films based on palmitoyl pentapeptide-4 (PP4) and phthalocyanine dye molecules were prepared by LB technique. The aggregation forms of phthalocyanine dye molecules and the structures/properties of composite films were studied. UV-Vis, FT-IR and SEM and other characterizations proved that the LB films are successfully composited, which may be due to the H-bonding, π-π stacking and electrostatic forces. Interestingly, the TPPS/PP4 LB films show excellent acid-alkali gas response. In addition, the surface-enhanced Raman scattering (SERS) demonstrate that the TsNiPc/PP4 LB film exhibits surface-enhancing properties for crystal violet (CV) molecules. Furthermore, the result demonstrate that the prepared LB films show good photocurrent generation efficiency. This work provides new clues for the preparation of self-assembled films and their applications as gas sensors, SERS and photoelectric device.

Air pollution in the places of Betula pendula growth and development changes the physicochemical properties and the main allergen content of its pollen.

Pollen allergy becomes an increasing problem for humans, especially in the regions, where the air pollution level increases due to the traffic and urbanization. These factors may also affect the physiological activity of plants, causing changes in pollen allergenicity. The aim of the study was to estimate the influence of air pollutants on the chemical composition of birch pollen and the secondary structures of the Bet v1 protein. The research was conducted in seven locations in Malopolska region, South of Poland of a different pollution level. We have found slight fluctuations in the values of parameters describing the photosynthetic light reactions, similar spectra of leaf reflectance and the negligible differences in the discrimination values of the δ13C carbon isotope were found. The obtained results show a minor effect of a degree of pollution on the physiological condition B. pendula specimen. On the other hand, mean Bet v1 concentration measured in pollen samples collected in Kraków was significantly higher than in less polluted places (p = .03886), while FT-Raman spectra showed the most distinct variations in the wavenumbers characteristic of proteins. Pollen collected at sites of the increased NOx and PM concentration, show the highest percentage values of potential aggregated forms and antiparallel β-sheets in the expense of α-helix, presenting a substantial impact on chemical compounds of pollen, Bet v1 concentration and on formation of the secondary structure of proteins, what can influence their functions.

Phycobilisomes and Phycobiliproteins in the Pigment Apparatus of Oxygenic Photosynthetics: From Cyanobacteria to Tertiary Endosymbiosis.

Eukaryotic photosynthesis originated in the course of evolution as a result of the uptake of some unstored cyanobacterium and its transformation to chloroplasts by an ancestral heterotrophic eukaryotic cell. The pigment apparatus of Archaeplastida and other algal phyla that emerged later turned out to be arranged in the same way. Pigment-protein complexes of photosystem I (PS I) and photosystem II (PS II) are characterized by uniform structures, while the light-harvesting antennae have undergone a series of changes. The phycobilisome (PBS) antenna present in cyanobacteria was replaced by Chl a/b- or Chl a/c-containing pigment-protein complexes in most groups of photosynthetics. In the form of PBS or phycobiliprotein aggregates, it was inherited by members of Cyanophyta, Cryptophyta, red algae, and photosynthetic amoebae. Supramolecular organization and architectural modifications of phycobiliprotein antennae in various algal phyla in line with the endosymbiotic theory of chloroplast origin are the subject of this review.

Asphaltenes: Aggregates in Terms of A1 and A2 or Island and Archipielago Structures.

In this work several issues related to asphaltenes and asphaltene aggregates such as isolation of real asphaltene molecules and comparison of these with average structures obtained using regular analytics laboratory techniques are presented. Several molecular organic models were used to simulate asphaltene in solution and aggregates formation in the two solvents toluene and THF employed. The results, obtained from simulation calculations using molecular dynamics were compared with experimental chromatography results obtained using the micro gel permeation chromatography (μGPC), inductively coupled plasma (ICP) mass spectra (MS) combined technique (GPC ICP MS for short). In this case reasonable hydrodynamic ratios and size distribution were obtained for asphaltenes and their corresponding subfractions A1 and subfraction A2. Comparison between experimental sample profiles, transmission of electron microscopy (TEM) data, and molecular dynamics allows for estimation of hydrodynamic ratios of around 8 nm. Highly aromatic and island type molecular model A30 and continental type molecular model A40 were employed in the molecular dynamics to built colloids. In this case open-like colloids (A40) and compact-like colloids A30 were obtained. Subjects such as trapped compounds (TC), metallic porphyrins, and colloidal dipole moments were also studied. Studies of the adsorption behavior of asphaltenes on several macroscopic and nanoscopic surfaces are presented and show the tendency of the asphaltene to adsorb in aggregate form.

Pathogenic tau decreases nuclear tension in cultured neurons.

Neurodegenerative tauopathies, including Alzheimer's disease, are pathologically defined by the presence of aggregated forms of tau protein in brains of affected individuals. Previous studies report that the negative effects of pathogenic tau on the actin cytoskeleton and microtubules cause a toxic destabilization of the lamin nucleoskeleton and formation of nuclear invaginations and blebs. Based on the known function of the nucleus as a mechanosensor, as well as the high incidence of nuclear pleomorphism in human Alzheimer's disease and related tauopathies, we investigated the effects of pathogenic tau on nuclear tension. We first find that tau-dependent nuclear envelope invagination and relocalization of LInker of Nucleoskeleton and Cytoskeleton (LINC) complex components are conserved in a newly-developed neuroblastoma cell line that features doxycycline-inducible expression of a tau mutant associated with autosomal dominant frontotemporal dementia. We next determine that a Förster resonance energy transfer (FRET)-based sensor of nuclear tension responds to cytoskeletal stabilization and destabilization when expressed in neuroblastoma cells. Using this nuclear tension sensor, we find that induced expression of pathogenic tau is sufficient to decrease nuclear tension. This work provides the initial proof-of-concept evidence that pathogenic forms of tau alter nuclear tension, paving the way for the future study of altered nuclear mechanosensing in the context of tau-mediated neurodegenerative disorders.

To Kill or to Be Killed: How Does the Battle between the UPS and Autophagy Maintain the Intracellular Homeostasis in Eukaryotes?

The ubiquitin-26S proteasome system and autophagy are two major protein degradation machineries encoded in all eukaryotic organisms. While the UPS is responsible for the turnover of short-lived and/or soluble misfolded proteins under normal growth conditions, the autophagy-lysosomal/vacuolar protein degradation machinery is activated under stress conditions to remove long-lived proteins in the forms of aggregates, either soluble or insoluble, in the cytoplasm and damaged organelles. Recent discoveries suggested an integrative function of these two seemly independent systems for maintaining the proteome homeostasis. One such integration is represented by their reciprocal degradation, in which the small 76-amino acid peptide, ubiquitin, plays an important role as the central signaling hub. In this review, we summarized the current knowledge about the activity control of proteasome and autophagosome at their structural organization, biophysical states, and turnover levels from yeast and mammals to plants. Through comprehensive literature studies, we presented puzzling questions that are awaiting to be solved and proposed exciting new research directions that may shed light on the molecular mechanisms underlying the biological function of protein degradation.

Filial imprinting in domestic chicks; cytoplasmic polyadenylation element binding protein 3, predispositions and learning.

Visual imprinting is a learning process, whereby young animals come to prefer a visual stimulus after exposure to it (training). Available evidence indicates that the intermediate medial mesopallium (IMM) in the domestic chick forebrain is a site of memory formation during visual imprinting. We have found previously that cytoplasmic polyadenylation element binding protein 3 in the P2 plasma membrane-mitochondrial fraction (CPEB3-P2) is upregulated in a learning-dependent way in the left IMM 24 h after training. CPEB3 has two forms, soluble and aggregated. Soluble CPEB3 represses translation; the aggregated form (CPEB3-AF) is amyloid-like and can promote translation. Our previous study did not show which of these two forms is increased after imprinting. We have now resolved this matter by measuring, 24 h after training, CPEB3-P2 and CPEB3-AF in the IMM and a control brain region, the posterior pole of nidopallium (PPN). The methods include imprinting training with a visual stimulus, behavioral measurement of preference, preparation of aggregated CPEB3, western immunoblotting, quantitation of proteins, statistical linear modeling. Only in the left IMM were the level of CPEB3-AF and learning strength correlated, increased CPEB3-AF level reflecting a predisposition to learn readily. CPEB3-P2 level also increased with learning strength in the left IMM, but as a result of learning. No correlations were detected in the right IMM or PPN. We propose two separate systems, both modulating synaptic strength through control of local translation. They are represented by CPEB3-AF (associated with a predisposition to learn) and soluble CPEB3 (associated with learning itself).

Alpha-synuclein oligomers alter the spontaneous firing discharge of cultured midbrain neurons.

The aim of this work was to monitor the effects of extracellular α-synuclein on the firing activity of midbrain neurons dissociated from substantia nigra TH-GFP mice embryos and cultured on microelectrode arrays (MEA). We monitored the spontaneous firing discharge of the network for 21 days after plating and the role of glutamatergic and GABAergic inputs in regulating burst generation and network synchronism. Addition of GABA A , AMPA and NMDA antagonists did not suppress the spontaneous activity but allowed to identify three types of neurons that exhibited different modalities of firing and response to applied L-DOPA: high-rate (HR) neurons, low-rate pacemaking (LR-p), and low-rate non-pacemaking (LR-np) neurons. Most HR neurons were insensitive to L-DOPA, while the majority of LR-p neurons responded with a decrease of the firing discharge; less defined was the response of LR-np neurons. The effect of exogenous α-synuclein (α-syn) on the firing discharge of midbrain neurons was then studied by varying the exposure time (0-48 h) and the α-syn concentration (0.3-70 μM), while the formation of α-syn oligomers was monitored by means of AFM. Independently of the applied concentration, acute exposure to α-syn monomers did not exert any effect on the spontaneous firing rate of HR, LR-p, and LR-np neurons. On the contrary, after 48 h exposure, the firing activity was drastically altered at late developmental stages (14 days in vitro, DIV, neurons): α-syn oligomers progressively reduced the spontaneous firing discharge (IC50 = 1.03 μM), impaired burst generation and network synchronism, proportionally to the increased oligomer/monomer ratio. Different effects were found on early-stage developed neurons (9 DIV), whose firing discharge remained unaltered, regardless of the applied α-syn concentration and the exposure time. Our findings unravel, for the first time, the variable effects of exogenous α-syn at different stages of midbrain network development and provide new evidence for the early detection of neuronal function impairment associated to aggregated forms of α-syn.

Enhanced loss but limited mobility of pyrogenic and organic matter in continuous permafrost-affected forest soils

Pyrogenic organic matter (PyOM) is a product of incomplete combustion during wildfires and an important pool of soil organic carbon (SOC). The dynamics of PyOM and SOC in boreal and permafrost-affected soils are largely unknown, while storing large amounts of global carbon and being vulnerable to climate change. Here, we traced the vertical mobility, allocation in soil fractions and decomposition losses of highly 13C-labeled PyOM and its precursor ryegrass organic matter (grass OM) after two years of in-situ incubation in soil cores installed in the upper 10 cm of continuous (northern sites) and discontinuous to sporadic (southern sites) permafrost-affected forest soils in Northern Canada. At the northern sites, up to three times more PyOM was lost by decomposition (39% of initial) compared to the southern sites (11% of initial). Losses of grass OM were substantial (69–84% of initial) and larger in southern soils. The vertical incorporation was limited and >90% of recovered PyOM and grass OM were found at the applied depth (0–3 cm). The PyOM strongly interacted with mineral surfaces, as indicated by around 40% recovered in the mineral-associated heavy density fractions (<63 μm). Microscale analyses by SEM and NanoSIMS showed that PyOM was mainly allocated towards the fine fraction in a particulate and aggregated form, highlighting the importance of abiotic processes for the incorporation of PyOM in permafrost-affected soils. The grass OM was mainly recovered in the mineral fractions at southern soils with enhanced allocation towards mineral surfaces as well as increased distribution at the microscale after initial decomposition, while it remained as particulate OM in northern soils. Our results highlight that permafrost-affected boreal forest soils are sensitive to fresh PyOM and OM inputs with substantial losses. Especially PyOM persistence depended on site and soil specific properties and not solely on its physico-chemical persistence. The responses are decoupled for PyOM and non-pyrolyzed OM and require a better understanding to evaluate carbon feedbacks of high-latitude soils with global warming and associated shifts in vegetation and wildfire regimes.

Study on the cracking behavior of asphalt mixture by discrete element modeling with real aggregate morphology

This research aimed to investigate the crack resistance of asphalt mixtures via laboratory tests and discrete element modelling. For the construction of virtual cracking model, the interactive 2D modeling method based on various software and the establishment method of 3D aggregate are proposed. The description method of crack path is also improved.When establishing the 2D model, considering the mesostructural characteristics of an AC-20 asphalt mixture, the aggregate-asphalt mortar-void three-phase structure was established based on PFC2D software and image processing. Taking into account the gradation and form of coarse aggregate, a 3D model incorporating real aggregate shapes was constructed by PFC3D. Based on the numerical model, semi-circular bending and tensile tests of specimens with pre-cut slits of different lengths were conducted to analyse their stress levels, cracking process and crack locations under low-temperature conditions. Taking the fracture performance parameters as an evaluation index, the feasibility of the numerical simulations was verified in comparison to laboratory test data. In the early phase of model loading, the stress distribution has the characteristics of a compression-tension zone. Crack formation undergoes a process of smooth expansion and rapid penetration, and cracks in the compression zone pass through the aggregate. The failure state presented by the particle flow program was in general agreement with the crack evolution results obtained from the tests. Additionally, the fracture parameters of the simulations had a favourable overlap with the experimental observations, indicating that the discrete element simulations can adequately represent the crack propagation process in asphalt mixes. This approach is effective for in-depth and efficient exploration of the cracking performance of asphalt mixtures.

Optimized operation of distributed energy resources: The opportunities of value stacking for Power-to-Gas aggregated with PV

This analysis investigates the business case of a virtually aggregated unit with PV and Power-to-Gas, outlining the added value of enhanced operation modes for the deepened market integration of distributed energy resources in an aggregated form. Based on empirical generation and market data, the presented analysis outlines the added benefit of the so-called value stacking that considers the exploitation of short-term arbitrage opportunities, the provision of secondary and tertiary frequency reserve, and active imbalance management to balance forecast errors. A multi-stage and multi-period optimization approach is presented to generate an aggregated bidding strategy on multiple energy and ancillary service markets. On a case study basis with hourly resolution, annual energy flows and financial outcomes are derived for the modelled plant. Overall, nine different operating modes with different levels of market integration of the aggregated unit are analysed. While static baseline operation results barely profitable, proper integration into energy markets raises the annual cash flow from operating activities to around 60 k€ per aggregated MW. This six-fold increase is accompanied by a much more price-specific dispatch with the equivalent full-load hours of controllable output effectively dropping to about one-third. Integrating the aggregated unit further into balancing markets and performing active imbalance management leverages the freed-up capacity margin and further increases the operational results up to 150 k€ per MW. The provided empirical insights from the case study are beneficial for both practitioners in the energy sector that want to evaluate the potential value of virtual aggregation with enhanced operation and policymakers that consider further regulatory amendments to open markets and enable further integration of new energy sources.

Amyloid Against Amyloid: Dimeric Amyloid Fragment Ameliorates Cognitive Impairments by Direct Clearance of Oligomers and Plaques

AbstractAmyloid‐β (Aβ) in the form of neurotoxic aggregates is regarded as the main pathological initiator and key therapeutic target of Alzheimer's disease. However, anti‐Aβ drug development has been impeded by the lack of a target needed for structure‐based drug design and low permeability of the blood–brain barrier (BBB). An attractive therapeutic strategy is the development of amyloid‐based anti‐Aβ peptidomimetics that exploit the self‐assembling nature of Aβ and penetrate the BBB. Herein, we designed a dimeric peptide drug candidate based on the N‐terminal fragment of Aβ, DAB, found to cross the BBB and solubilize Aβ oligomers and fibrils. Administration of DAB reduced amyloid burden in 5XFAD mice, and downregulated neuroinflammation and prevented memory impairment in the Y‐maze test. Peptide mapping assays and molecular docking studies were utilized to elucidate DAB‐Aβ interaction. To further understand the active regions of DAB, we assessed the dissociative activity of DAB with sequence modifications.

Amyloid Against Amyloid: Dimeric Amyloid Fragment Ameliorates Cognitive Impairments by Direct Clearance of Oligomers and Plaques.

Amyloid-β (Aβ) in the form of neurotoxic aggregates is regarded as the main pathological initiator and key therapeutic target of Alzheimer's disease. However, anti-Aβ drug development has been impeded by the lack of a target needed for structure-based drug design and low permeability of the blood-brain barrier (BBB). An attractive therapeutic strategy is the development of amyloid-based anti-Aβ peptidomimetics that exploit the self-assembling nature of Aβ and penetrate the BBB. Herein, we designed a dimeric peptide drug candidate based on the N-terminal fragment of Aβ, DAB, found to cross the BBB and solubilize Aβ oligomers and fibrils. Administration of DAB reduced amyloid burden in 5XFAD mice, and downregulated neuroinflammation and prevented memory impairment in the Y-maze test. Peptide mapping assays and molecular docking studies were utilized to elucidate DAB-Aβ interaction. To further understand the active regions of DAB, we assessed the dissociative activity of DAB with sequence modifications.

Tau and tubulin protein aggregation characterization by solid-state nanopore method and atomic force microscopy

In this study, a silicon nitride nanopore-based sensing system was used to measure tau and tubulin monomers and their aggregations in salt solution at a single molecule level. Nanopores (6–30 nm) were fabricated on silicon nitride membranes supported by silicon substrates using a combination of focused ion beam milling and ion beam sculpting. When a charged protein molecule in the salt solution passes through a nanopore driven by an applied voltage, the protein molecule increases pore resistivity, which induces an ionic current drop that can be measured. The current drop amplitude is directly proportional to the local excluded volume of the protein molecule in the nanopore. We measured the monomers and aggregations of tau and tubulin proteins at biased voltages from 60 to 210 mV in a solution of pH 7.0–10. Our results showed that (1) the nanopore method was able to differentiate tau and tubulin proteins in their monomer and aggregated forms by their excluded volumes; (2) the most probable aggregation form was dimer for α- and β-tubulin and pentamer for αβ tubulin plus tau under experimental conditions; (3) the protein excluded volumes measured by the nanopore method depended on the applied voltage, and this observation could be explained by the nonuniform charge distribution of proteins. The monomer and aggregated proteins were further analyzed using atomic force spectroscopy (AFM), and protein volumes estimated by AFM were consistent with nanopore results.

Utilization of Different Forms of Demolished Clay Brick and Granite Wastes for Better Performance in Cement Composites

Clay brick and granite waste are part of the waste generated by construction and demolition activities. The amount of these wastes generated is enormous, but on the one hand, they can be used as a raw material for cement mixtures; thus, it is important to find ways to utilize them efficiently. In this study, clay brick and granite waste were crushed and screened into two size fractions (0.15–2.36 mm for sand replacement and smaller than 0.15 mm for cement replacement), and a total of four different forms of recycled materials were obtained (recycled brick aggregate, recycled brick powder, recycled granite aggregate and recycled granite powder) and used in cement mortar. Various properties (workability, mechanical strength and drying shrinkage) of the mortars were assessed according to standardized test methods. The results showed that the various material forms had different effects on the various properties of cement mortar. At replacement ratios of 10% and 20%, recycled granite showed better workability when used as powder, whereas recycled brick used as aggregate had higher workability. In common, using recycled brick and recycled granite in the form of aggregate was advantageous for the strength development of mortar, while using them in the form of powder helped to mitigate drying shrinkage.

Diabetes mellitus and inequalities in the equipment and use of information technologies as a socioeconomic determinant of health in Spain.

Inequalities in the equipment and use of information and communications technology (ICT) in Spanish households can lead to users being unable to access certain information or to carry out certain procedures. Accessibility to ICT is considered a social determinant of health (SDOH) because it can generate inequalities in access to information and in managing access to health services. In the face of a chronic illness such as diabetes mellitus (DM)-for which a comprehensive approach is complex and its complications have a direct impact on current healthcare systems-all the resources that patients may have are welcome. We aimed to analyze hospitalizations and amputations as direct consequences of DM among the autonomous communities of Spain (ACS) in 2019, along with socioeconomic factors related to health, including inequalities in access to ICT between territories, as well as citizens' interest in online information searches about DM. We used different databases such as that of the Ministerio de Sanidad (Spain's health ministry), Ministerio de Asuntos Económicos y transformación (Ministry of Economic Affairs and Digital Transformation), Google Trends (GT), and the Instituto Nacional de Estadística (Spain's national institute of statistics). We examined the data with R software. We employed a geolocation approach and performed multivariate analysis (specifically factor analysis of mixed data [FAMD]) to evaluate the aggregate interest in health information related to DM in different regions of Spain grounded in online search behavior. The use of FAMD allowed us to adjust the techniques of principal component analysis (PCA) and multiple correspondence analysis (MCA) to detect differences between the direct consequences of DM, citizen's interest in this non-communicable disease, and socioeconomic factors and inequalities in access to ICT in aggregate form between the country's different ACS. The results show how SDOH, such as poverty and education level, are related to the ACS with the highest number of homes that cite the cost of connection or equipment as the reason for not having ICT at home. These regions also have a greater number of hospitalizations due to DM. Given that in Spain, there are certain differences in accessibility in terms of the cost to households, in the case of DM, we take this issue into account from the standpoint of an integral approach by health policies.

Dissolvable alginate hydrogel-based biofilm microreactors for antibiotic susceptibility assays

Biofilms are found in many infections in the forms of surface-adhering aggregates on medical devices, small clumps in tissues, or even in synovial fluid. Although antibiotic resistance genes are studied and monitored in the clinic, the structural and phenotypic changes that take place in biofilms can also lead to significant changes in how bacteria respond to antibiotics. Therefore, it is important to better understand the relationship between biofilm phenotypes and resistance and develop approaches that are compatible with clinical testing. Current methods for studying antimicrobial susceptibility are mostly planktonic or planar biofilm reactors. In this work, we develop a new type of biofilm reactor—three-dimensional (3D) microreactors—to recreate biofilms in a microenvironment that better mimics those in vivo where bacteria tend to form surface-independent biofilms in living tissues. The microreactors are formed on microplates, treated with antibiotics of 1000 times of the corresponding minimal inhibitory concentrations (1000 × MIC), and monitored spectroscopically with a microplate reader in a high-throughput manner. The hydrogels are dissolvable on demand without the need for manual scraping, thus enabling measurements of phenotypic changes. Bacteria inside the biofilm microreactors are found to survive exposure to 1000 × MIC of antibiotics, and subsequent comparison with plating results reveals no antibiotic resistance-associated phenotypes. The presented microreactor offers an attractive platform to study the tolerance and antibiotic resistance of surface-independent biofilms such as those found in tissues.

Microstructural characterisation and analysis of coarse aggregates in asphalt drill cores

The research presented in this paper is focused on the three-dimensional characterisation of coarse aggregates ( mm) within real asphalt structures. It is based on three-dimensional images acquired by micro X-ray Computed Tomography (μXRCT). A method to segment the aggregates from the other asphalt mixture components and each other, using these images is presented in detail. Subsequently, they are converted into basic data on the aggregate size, form, structure and orientation of every individual aggregate. On this database, fundamental and generally used parameters are calculated to characterise the aggregate properties. Finally, the parameters are evaluated regarding the aggregate form, angularity, location within the drill core and alignment of its main dimension. The results show that the segmentation method delivers quite precise results about the aggregates. The analysis of those basic parameters points out that the aggregates' positioning is evenly distributed but the orientation behaviour inside the structure is dependent on their shape characteristics.

Effect of microwave electric field on asphaltene aggregation in a heavy oil system: MD and DFT investigation

An in-depth understanding of asphaltene aggregation is vital for the viscosity reduction of heavy oils, and essential for fully utilizing heavy oil resources. Therefore, the influence of microwave electric field on the aggregation of asphaltene in the heavy oil system was investigated via Molecular Dynamic simulation and Density Functional Theory calculation. The aggregation forms, interaction types and rheological behavior of asphaltene and other components were calculated by processing the trajectories. The results reveal that microwave electric fields play a significant role in the packing morphology of asphaltenes and other components at the micro-molecular level, leading to changes in the apparent viscosity of heavy oil system. It can be clearly manifested that under 5 V/nm of microwave electric field, asphaltenes primarily stack in π - π, connecting intimately with resin, constructing a stable colloidal structure of the system with high viscosity. Whereas, by enhancing the electric field, π-π stacking will gradually be destroyed, resulting in viscosity reduction. The T-shaped stacking of asphaltenes is favorable to form at 20 V/nm, inducing a stable network among the components, which is detrimental to the viscosity reduction. The achievements further confirm that an appropriate microwave electric field is the key to reducing the viscosity. In addition, considering the thermal and non-thermal effects of microwave, it is explored that microwave is more effective at low temperature. Therefore, the efficient combination of microwave power and treatment temperature is the critical factor to achieve better viscosity reduction effect.

Mixing of Excitons in Nanostructures Based on a Perylene Dye with CdTe Quantum Dots.

Semiconductor quantum dots of the A2B6 group and organic semiconductors have been widely studied and applied in optoelectronics. This study aims to combine CdTe quantum dots and perylene-based dye molecules into advanced nanostructure system targeting to improve their functional properties. In such systems, new electronic states, a mixture of Wannier-Mott excitons with charge-transfer excitons, have appeared at the interface of CdTe quantum dots and the perylene dye. The nature of such new states has been analyzed by absorption and photoluminescence spectroscopy with picosecond time resolution. Furthermore, aggregation of perylene dye on the CdTe has been elucidated, and contribution of Förster resonant energy transfer has been observed between aggregated forms of the dye and CdTe quantum dots in the hybrid CdTe-perylene nanostructures. The studied nanostructures have strongly quenched emission of quantum dots enabling potential application of such systems in dissociative sensing.