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Highly-Soluble Cyanine J-aggregates Entrapped by Liposomes for <i>In Vivo</i> Optical Imaging around 930 nm
摘要： Near infrared (NIR) dyes are useful for in vivo optical imaging. Liposomes have been used extensively for delivery of diverse cargos, including hydrophilic cargos which are passively loaded in the aqueous core. However, most currently available NIR dyes are only slightly soluble in water, making passive entrapment in liposomes challenging for achieving high optical contrast. Methods: We modified a commercially-available NIR dye (IR-820) via one-step Suzuki coupling with dicarboxyphenylboronic acid, generating a disulfonated heptamethine; dicarboxyphenyl cyanine (DCP-Cy). DCP-Cy was loaded in liposomes and used for optical imaging. Results: Owing to increased charge in mildly basic aqueous solution, DCP-Cy had substantially higher water solubility than indocyanine green (by an order of magnitude), resulting in higher NIR absorption. Unexpectedly, DCP-Cy tended to form J-aggregates with pronounced spectral red-shifting to 934 nm (from 789 nm in monomeric form). J-aggregate formation was dependent on salt and DCP-Cy concentration. Dissolved at 20 mg/mL, DCP-Cy J-aggregates could be entrapped in liposomes. Full width at half maximum absorption of the liposome-entrapped dye was just 25 nm. The entrapped DCP-Cy was readily detectable by fluorescence and photoacoustic NIR imaging. Upon intravenous administration to mice, liposomal DCP-Cy circulated substantially longer than the free dye. Accumulation was largely in the spleen, which was visualized with fluorescence and photoacoustic imaging. Conclusions: DCP-Cy is simple to synthesize and exhibits high aqueous solubility and red-shifted absorption from J-aggregate formation. Liposomal dye entrapment is possible, which facilitates in vivo photoacoustic and fluorescence imaging around 930 nm.
关键词： liposomes,photoacoustic,cyanine,J-aggregate
更新于2025-09-23 15:22:29
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Nepafenac-Loaded Cyclodextrin/Polymer Nanoaggregates: A New Approach to Eye Drop Formulation
摘要： The topical administration route is commonly used for targeting therapeutics to the eye; however, improving the bioavailability of drugs applied directly to the eye remains a challenge. Different strategies have been studied to address this challenge. One of them is the use of aggregates that are formed easily by self-assembly of cyclodextrin (CD)/drug complexes in aqueous solution. The aim of this study was to design a new eye drop formulation based on aggregates formed between CD/drug complexes. For this purpose, the physicochemical properties of the aggregates associated with six CDs and selected water-soluble polymers were analysed. Complex formation was studied using differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (1H-NMR). Results showed that HPβCD performed best in terms of solubilization, while γCD performed best in terms of enhancing nanoaggregate formation. Formation of inclusion complexes was con?rmed by DSC, FT-IR and 1H-NMR studies. A mixture of 15% (w/v) γCD and 8% (w/v) HPβCD was selected for formulation studies. It was concluded that formulations with aggregate sizes less than 1 μm and viscosity around 10–19 centipoises can be easily prepared using a mixture of CDs. Formulations containing polymeric drug/CD nanoaggregates represent an interesting strategy for enhanced topical delivery of nepafenac.
关键词： cyclodextrin,self-assemble,nepafenac,aggregate,polymer,complexation,ocular drug delivery
更新于2025-09-23 15:22:29
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Influence of Platelet Aggregate Formation in Blood Samples on Light Transmission Aggregometry Results
摘要： Background: Light transmission aggregometry is a standard method used to evaluate platelet function. However, in clinical settings, light transmission aggregometry results sometimes fail to reflect actual platelet hyperactivity. In patients with suspected platelet hyperactivity such as thrombosis, platelet aggregates are frequently detected in citrated blood samples using a scattergram of a hematology analyzer. This study aimed to evaluate the effects of platelet aggregate formation on light transmission aggregometry results. Methods: We used 19 citrated blood samples in which platelet aggregate formation was intentionally induced by a hematology analysis process. Employing fully automated light transmission aggregometry and agonists including adenosine diphosphate or collagen, light transmission aggregometry maximum aggregation percentage, platelet count, and mean platelet volume of platelet-rich plasma before and after platelet aggregate formation were evaluated. Results: Light transmission aggregometry maximum aggregation percentage with adenosine diphosphate or collagen was significantly lower in the samples after than before platelet aggregate formation. Platelet count and mean platelet volume were both decreased by platelet aggregate formation (P < .01), suggesting that maximum aggregation percentage reduction was caused by the decrease in activated large platelets in the platelet-rich plasma. Conclusion: This study clarified that platelet aggregate formation in blood samples interfered with an accurate assessment of platelet hyperactivity. To ensure reliability of light transmission aggregometry results, we must confirm that platelet aggregates have not formed in the sample, especially in those of patients with platelet hyperactivity.
关键词： platelet count,hematology analyzer,light transmission aggregometry,mean platelet volume,platelet-rich plasma,Platelet aggregate
更新于2025-09-23 15:22:29
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Photo-Annealing of Merocyanine Aggregates
摘要： In this work we elucidate the fundamental difference between aggregate formation of donor-π-acceptor merocyanines in their electronic ground and excited states. While increasing the π-bridge size favors formation of π-stacked aggregates in the dark, irradiation with visible light causes reorientation of the dyes to form prototype H-aggregates with compensating dipole moments. This photo-annealing changes the supramolecular structure and its UV-vis spectroscopic properties dramatically, thus being of importance for the function of active layers composed of these dyes. Aggregates of the ground state dyes are bound cooperatively through ππ-London dispersion interactions and hydrogen bonds between the polar α-cyano-carboxylic acid groups. However, charge transfer upon photoexcitation leads to repulsion of the polar acid groups. Electronic excitation of the dyes approximately doubles the ground state dipole moment, thus driving molecular reorientation into prototype H-aggregate structures. We show that this photo-induced supramolecular rearrangement can disrupt the large polymeric aggregates formed in the dark. The photo-induced supramolecular structural changes reported in this work will influence the performance of optoelectronic devices composed of these structures and must be controlled to avoid morphological decomposition of active layers upon operation.
关键词： merocyanines,photo-annealing,H-aggregates,supramolecular structure,UV-vis spectroscopy,dipole moments,aggregate formation
更新于2025-09-23 15:21:21
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Molecular Packing: Another Key Point for the Performance of Organic and Polymeric Optoelectronic Materials
摘要： Optoelectronic material properties are governed by the whole collective of organic moieties, and these aggregate states present the characteristic performance of extended assemblies with different molecular packing, not only of single molecules themselves. Thus, controlling molecular packing is an essential issue for obtaining the optimized optical and electronic properties. It is also a great challenge because of the unclear structures and complicated intermolecular interactions, including dispersion forces, electrostatic interactions and hydrogen bonding. Moreover, upon the introduction of some external force as the stimulus source, dynamic optical properties can be achieved with the transformation of the photoinduced room temperature molecular packing in some cases, phosphorescence (RTP) effect, mechanochromic luminescence, treatment-dependent mechanoluminescence effect, and the optimized nonlinear optical (NLO) property achieved after electric poling. Therefore, it is essential to understand the relation between characteristics of molecular packing and the resultant optoelectronic performance at the molecular level, which becomes increasingly demanding for the further development of functional materials for their applications in organic light-emitting diodes (OLEDs), chemo- and biosensors, organic solar cells, data storage, and anticounterfeiting devices.
关键词： aggregate states,dynamic optical properties,optoelectronic materials,molecular packing,intermolecular interactions
更新于2025-09-23 15:21:01
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Proposal of Photonic Analog-to-digital Conversion Using Weighted Multiwavelength Pulses and Balanced Photodetector
摘要： Nowadays, enhanced knowledge of the nature of the electricity demand is achieved through the progressively increasing deployment of smart meters and advanced data analysis techniques. One of the major challenges is to exploit this knowledge to support the introduction of strategies to modify the demand according to relevant objectives to be achieved, like users’ participation in demand response programmes. A key point for facing this challenge is to characterize the demand flexibility. In spite of many discussions about the concept of flexibility, the few mathematical definitions of flexibility available do not address the variation in time of the overall demand aggregation. This paper starts from the analysis of time-variable patterns of aggregate residential customers, ending up with suitable definitions of expected flexibility for aggregate demand. These definitions are based on assessing positive and negative pattern variations and are identified from the analysis of the collective behavior of the aggregate users. A set of results is shown for different numbers of aggregate customers, by considering different values of the averaging time step for load pattern representation.
关键词： binomial probability,customers,demand flexibility,Aggregate demand,electrical load,demand response,load variation pattern,maximum likelihood estimation
更新于2025-09-23 15:21:01
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Evaluation of the Efficacy of Erbium, Chromium-doped Yttrium, Scandium, Gallium, and Garnet Laser in Partial Pulpotomy in Permanent Immature Molars: A Randomized Controlled Trial
摘要： Introduction: The use of the erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser in vital pulp therapy contributes to the formation of dentin bridges and a sterile zone as well as the maintenance of the vitality of the pulp. However, no prior studies have used the Er,Cr:YSGG laser in partial pulpotomy of immature permanent teeth. The aim of this study was to compare the ef?cacy of partial pulpotomy treatment using mineral trioxide aggregate (MTA) alone and MTA with the Er,Cr:YSGG laser in permanent immature molars. Methods: A total of 90 caries-exposed permanent immature molar teeth were included and randomly divided into 2 groups: the MTA group (n 5 45) and the laser 1 MTA group (n 5 45). In the MTA group, MTA was applied to the exposed area on the pulp after bleeding control. In the same session, the tooth was restored with a composite resin. In the laser 1 MTA group, before MTA condensation, the Er,Cr:YSGG laser was applied to the exposure area. Patients were recalled at 1, 3, 6, and 12 months after treatment. The Mann-Whitney U and chi-Square tests were used for statistical analysis. Results: The success rate (95.5%) of the laser 1 MTA group was similar to that of the MTA group (88.8%). There was no signi?cant difference between groups in terms of the frequency of at least 1 pathologic clinical or radiographic failure at 12 months (P . .05). Conclusions: Partial pulpotomy treatment showed a high success rate in immature permanent molars; however, the use of the laser did not contribute to the success rate compared with MTA alone.
关键词： mineral trioxide aggregate,partial pulpotomy,Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser,immature teeth
更新于2025-09-23 15:21:01
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Null Exciton Splitting in Chromophoric Greek Cross?(+) Aggregate
摘要： Exciton interactions in molecular aggregates play a crucial role in tailoring the optical behaviour of p-conjugated materials. Though vital for optoelectronic applications, ideal Greek cross-dipole (a = 908) stacking of chromophores remains elusive. We report a novel Greek cross (+) assembly of 1,7-dibromoperylene-3,4,9,10-tetracarboxylic tetrabutylester (PTE-Br2) which exhibits null exciton coupling mediated monomer-like optical characteristics in the crystalline state. In contrast, nonzero exciton coupling in X-type (a = 70.28, PTE-Br0) and J-type (a = 08, q = 48.48, PTE-Br4) assemblies have perturbed optical properties. Additionally, the semi-classical Marcus theory of charge-transfer rates predicts a selective hole transport phenomenon in the orthogonally stacked PTE-Br2. Precise rotation angle dependent optoelectronic properties in crystalline PTE-Br2 can have consequences in the rational design of novel p-conjugated materials for photonic and molecular electronic applications.
关键词： crystal engineering,chromophore aggregate,fluorescence,charge mobility,exciton splitting
更新于2025-09-23 15:21:01
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - 2Gps OFDM Visible Light Communication Using Light-emitting Diodes with Photonic Crystals
摘要： Nowadays, enhanced knowledge of the nature of the electricity demand is achieved through the progressively increasing deployment of smart meters and advanced data analysis techniques. One of the major challenges is to exploit this knowledge to support the introduction of strategies to modify the demand according to relevant objectives to be achieved, like users’ participation in demand response programmes. A key point for facing this challenge is to characterize the demand flexibility. In spite of many discussions about the concept of flexibility, the few mathematical definitions of flexibility available do not address the variation in time of the overall demand aggregation. This paper starts from the analysis of time-variable patterns of aggregate residential customers, ending up with suitable definitions of expected flexibility for aggregate demand. These definitions are based on assessing positive and negative pattern variations and are identified from the analysis of the collective behavior of the aggregate users. A set of results is shown for different numbers of aggregate customers, by considering different values of the averaging time step for load pattern representation.
关键词： demand response,binomial probability,maximum likelihood estimation,customers,demand flexibility,electrical load,Aggregate demand,load variation pattern
更新于2025-09-23 15:19:57
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Secure Smart Cameras by Aggregate-Signcryption with Decryption Fairness for Multi-Receiver IoT Applications
摘要： Smart cameras are key sensors in Internet of Things (IoT) applications and often capture highly sensitive information. Therefore, security and privacy protection is a key concern. This paper introduces a lightweight security approach for smart camera IoT applications based on elliptic-curve (EC) signcryption that performs data signing and encryption in a single step. We deploy signcryption to efficiently protect sensitive data onboard the cameras and secure the data transfer from multiple cameras to multiple monitoring devices. Our multi-sender/multi-receiver approach provides integrity, authenticity, and confidentiality of data with decryption fairness for multiple receivers throughout the entire lifetime of the data. It further provides public verifiability and forward secrecy of data. Our certificateless multi-receiver aggregate-signcryption protection has been implemented for a smart camera IoT scenario, and the runtime and communication effort has been compared with single-sender/single-receiver and multi-sender/single-receiver setups.
关键词： elliptic-curve signcryption,resource efficiency,smart cameras,Internet of Things,multi-receiver aggregate-signcryption,data security
更新于2025-09-19 17:15:36