133 research outputs found
Secure and Privacy-Preserving Data Sharing and Collaboration in Mobile Healthcare Social Networks of Smart Cities
Mobile healthcare social networks (MHSN) integrated with connected medical sensors and cloud-based health data storage provide preventive and curative health services in smart cities. The fusion of social data together with real-time health data facilitates a novel paradigm of healthcare big data analysis. However, the collaboration of healthcare and social network service providers may pose a series of security and privacy issues. In this paper, we propose a secure health and social data sharing and collaboration scheme in MHSN. To preserve the data privacy, we realize secure and fine-grained health data and social data sharing with attribute-based encryption and identity-based broadcast encryption techniques, respectively, which allows patients to share their private personal data securely. In order to achieve enhanced data collaboration, we allow the healthcare analyzers to access both the reencrypted health data and the social data with authorization from the data owner based on proxy reencryption. Specifically, most of the health data encryption and decryption computations are outsourced from resource-constrained mobile devices to a health cloud, and the decryption of the healthcare analyzer incurs a low cost. The security and performance analysis results show the security and efficiency of our scheme
Identification of the enterprise financialization motivation on crowding out R&D innovation: evidence from listed companies in China
Enterprise financial asset allocation depends on its motivation, which significantly influences its R&D innovation. In this study, we theoretically analyzed the motivation behind the crowding-out effect of enterprise financialization on R&D innovation and constructed a panel data model to identify enterprise financialization behavior. Furthermore, we analyzed the characteristics of enterprises with two types of effects on R&D innovation: Crowding-out and non-crowding-out. Using disclosed data from listed companies in China as the sample, the following conclusions were drawn. First, there are two types of motivation for enterprise financial assets: reservoir motivation and substitute motivation. This difference in motivation leads to whether there is a crowding-out effect of enterprise financialization on R&D innovation. Second, based on whether there is a crowding-out effect on enterprise R&D innovation, we found that the difference in reservoir motivation between the two types of samples is reflected in the intensity of inhibition, while the difference in substitute motivation is reflected in significance. Third, there are differences in the mechanism variables of financialization motivation among different samples. The moderating effect of equity concentration is reflected in its intensity, while the moderating effect of financing constraints is reflected in its significance
An Improved D-α-Tocopherol-Based Nanocarrier for Targeted Delivery of Doxorubicin with Reversal of Multidrug Resistance
Nanocarriers have recently emerged as an attractive platform for delivery of various types of therapeutics including anticancer agents. Previously, we developed an improved TPGS delivery system (PEG5K-VE2) which demonstrated improved colloidal stability and greater in vivo antitumor activity. Nevertheless, the application of this system is still limited by a relatively low drug loading capacity (DLC). In this study we report that incorporation of a fluorenylmethyloxycarbonyl (Fmoc) motif at the interfacial region of PEG5K-VE2 led to significant improvement of the system through the introduction of an additional mechanism of drug/carrier interaction. Doxorubicin (DOX) could be effectively loaded into PEG5K-Fmoc-VE2 micelles at a DLC of 39.9%, which compares favorably to most reported DOX nanoformulations. In addition, PEG5K-Fmoc-VE2/DOX mixed micelles showed more sustained release of DOX in comparison to the counterpart without Fmoc motif. MTT assay showed that PEG5K-Fmoc-VE2/DOX exerted significantly higher levels of cytotoxicity over DOX, Doxil as well as PEG5K-VE2/DOX in PC-3 and 4T1.2 cells. Cytotoxicity assay with NCI/ADR-RES, a drug resistant cell line, suggested that PEG5K-Fmoc-VE2 may have a potential to reverse the multidrug resistance, which was supported by its inhibition on P-gp ATPase. Pharmacokinetics (PK) and biodistribution studies showed an increased half-life in blood circulation and more effective tumor accumulation for DOX formulated in PEG5K-Fmoc-VE2 micelles. More importantly, DOX-loaded PEG5K-Fmoc-VE2 micelles showed an excellent safety profile with a MTD (~30 mg DOX/kg) that is about 3 times as much as that for free DOX. Finally, superior antitumor activity was demonstrated for PEG5K-Fmoc-VE2/DOX in both drug-sensitive (4T1.2 and PC-3) and drug-resistant (KB 8-5) tumor models compared to DOX, Doxil, and PEG5K-VE2/DOX
A PEG-Fmoc conjugate as a nanocarrier for paclitaxel
We report here that a simple, well-defined, and easy-to-scale up nanocarrier, PEG5000-lysyl-(α-Fmoc-ε-t-Boc-lysine)2 conjugate (PEG-Fmoc), provides high loading capacity, excellent formulation stability and low systemic toxicity for paclitaxel (PTX), a first-line chemotherapeutic agent for various types of cancers. 9-Fluorenylmethoxycarbonyl (Fmoc) was incorporated into the nanocarrier as a functional building block to interact with drug molecules. PEG-Fmoc was synthesized via a three-step synthetic route, and it readily interacted with PTX to form mixed nanomicelles of small particle size (25–30 nm). The PTX loading capacity was about 36%, which stands well among the reported micellar systems. PTX entrapment in this micellar system is achieved largely via an Fmoc/PTX π-π stacking interaction, which was demonstrated by fluorescence quenching studies and 13C-NMR. PTX formulated in PEG-Fmoc micelles demonstrated sustained release kinetics, and in vivo distribution study via near infrared fluorescence imaging demonstrated an effective delivery of Cy5.5-labled PTX to tumor sites. The maximal tolerated dose for PTX/PEG-Fmoc (MTD > 120 mg PTX/kg) is higher than those for most reported PTX formulations, and in vivo therapeutic study exhibited a significantly improved antitumor activity than Taxol, a clinically used formulation of PTX. Our system may hold promise as a simple, safe, and effective delivery system for PTX with a potential for rapid translation into clinical study
Ferroptosis in hematological malignant tumors
Ferroptosis is a kind of iron-dependent programmed cell death discovered in recent years. Its main feature is the accumulation of lipid reactive oxygen species in cells, eventually leading to oxidative stress and cell death. It plays a pivotal role in normal physical conditions and the occurrence and development of various diseases. Studies have shown that tumor cells of the blood system, such as leukemia cells and lymphoma cells, are sensitive to the response to ferroptosis. Regulators that modulate the Ferroptosis pathway can accelerate or inhibit tumor disease progression. This article reviews the mechanism of ferroptosis and its research status in hematological malignancies. Understanding the mechanisms of ferroptosis could provide practical guidance for treating and preventing these dreaded diseases
Electrochemical Synthesis of Silver-Tetracyanoquinodimethane Nanorods at Agar Supported Water/1,2-Dichloroethane Interface
具有高导电性和独特电学性质的金属有机络合物AgTCNQ是一种重要的电荷转移盐.本文采用琼脂作为胶凝剂构成水|1,2-二氯乙烷液液界面;施加电压时银离子由水相穿过水凝胶进入有机相,与TCNQ-反应生成AgTCNQ纳米棒.结果表明液/液界面电化学方法为合成有机金属功能材料的有效途径.Silver-tetracyanoquinodimethane (AgTCNQ) is an important charge transfer salt due to its high conductivity and other electronic properties. In this communication, we report the synthesis of AgTCNQ at the liquid/liquid interface. Agar was used as a gelling agent to support water/1,2-dichloroethane (DCE) interface. Silver ions were transferred from the hydrogel into DCE phase, where they combined with TCNQ- to form AgTCNQ nanorods. The developed method can provide a new route for synthesis of functional materials based on the electrochemistry at the liquid/liquid interface.This work was supported by National Science Foundation of China (No. 20973142, No. 21061120456, and No. 21021002), National Basic Research Program of China (2011CB933700) and the National Science Foundation (CHE-1026582; MVM).This work was supported by National Science Foundation of China (No. 20973142, No. 21061120456, and No. 21021002), National Basic Research Program of China (2011CB933700) and the National Science Foundation (CHE-1026582; MVM).作者联系地址:1. 厦门大学化学化工学院化学系, 福建厦门361005; 2. 厦门大学固体表面物理化学国家重点实验室, 福建厦门361005; 3. 纽约市立大学皇后学院化学与生物化学系袁美国纽约11367Author's Address: 1. Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China; 2. State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, Fujian, China; 3. Department of Chemistry and Biochemistry, Queens College-CUNY, Flushing, New York 11367, USA通讯作者E-mail:[email protected]
Biosynthesis of Gold Nanoparticles by Foliar Broths: Roles of Biocompounds and Other Attributes of the Extracts
Biosynthesis of nanoparticles has arisen as a promising alternative to conventional synthetic methodologies owing to its eco-friendly advantages, and the involved bioprotocol still needs further clarification. This research, for the first time from the standpoint of statistics, confirmed an electrostatic force or ionic bond-based interaction between the chloroauric ions and the involved bioconstituents and manifested that reducing sugars and flavonoids were both important reductants responsible for conversion of Au(III) to Au(0). The result also demonstrated that the proteins were not the reducing agents, yet they might be protection agents in biosynthesis of gold nanoparticles (GNPs). Besides, a significant linear relationship was found between the anti-oxidant ability of the foliar broths and their capability to reduce Au(III) into Au(0). Furthermore, the preliminary investigation based on the boxplot on the size/shape distribution of the biosynthesized GNPs revealed that gold nanospheres with higher degree of homogeneity in size tended to be promoted by foliar broths containing higher content of reducing sugars/flavonoids and proteins. Otherwise, i.e., for those broths with lower content of the above biocompounds, sphere GNPs of wider size distribution or even gold nanotriangles tended to be fabricated
New Trends in Impedimetric Biosensors for the Detection of Foodborne Pathogenic Bacteria
The development of a rapid, sensitive, specific method for the foodborne pathogenic bacteria detection is of great importance to ensure food safety and security. In recent years impedimetric biosensors which integrate biological recognition technology and impedance have gained widespread application in the field of bacteria detection. This paper presents an overview on the progress and application of impedimetric biosensors for detection of foodborne pathogenic bacteria, particularly the new trends in the past few years, including the new specific bio-recognition elements such as bacteriophage and lectin, the use of nanomaterials and microfluidics techniques. The applications of these new materials or techniques have provided unprecedented opportunities for the development of high-performance impedance bacteria biosensors. The significant developments of impedimetric biosensors for bacteria detection in the last five years have been reviewed according to the classification of with or without specific bio-recognition element. In addition, some microfluidics systems, which were used in the construction of impedimetric biosensors to improve analytical performance, are introduced in this review
- …