The rapid development of the Internet of Things (IoT) and the explosive growth of valuable data produced by user equipment have led to strong demand for access control, especially hierarchical access ...control, which is performed from a group communication perspective. However, the key management strategies for such a future Internet are based mostly on a trusted third party that requires full trust of the key generation center (KGC) or central authority (CA). Recent studies indicate that centralized cloud centers will be unlikely to deliver satisfactory services to customers because we place too much trust in third parties; therefore, these centers do not apply to user privacy-oriented scenarios. This paper addresses these issues by proposing a novel blockchain-based distributed key management architecture (BDKMA) with fog computing to reduce latency and multiblockchains operated in the cloud to achieve cross-domain access. The proposed scheme utilizes blockchain technology to satisfy the decentralization, fine-grained auditability, high scalability, and extensibility requirements, as well as the privacy-preserving principles for hierarchical access control in IoT. We designed system operations methods and introduced different authorization assignment modes and group access patterns to reinforce the extensibility. We evaluated the performance of our proposed architecture and compared it with existing models using various performance measures. The simulation results show that the multiblockchain structure substantially improves system performance, and the scalability is excellent as the network size increases. Furthermore, dynamic transaction collection time adjustment enables the performance and system capacity to be optimized for various environments.
A new type of eco-friendly molecularly imprinted polymer (MIP) was synthesized through an efficient one-pot room-temperature sol–gel polymerization and applied as a molecular recognition element to ...construct dopamine (DA) fluorescence (FL) optosensor. Highly luminescent carbon dots (CDs) were firstly synthesized via a one-step reaction in organosilane, and their surface were anchored with MIP matrix (CDs@MIP). The resulting composite of a synergetic combination of CDs with MIP showed high photostability and template selectivity. Moreover, the composite allowed a highly sensitive determination of DA via FL intensity decreasing when removal of the original templates. The new MIP-based DA sensing protocol was applied to detect DA concentration in aqueous solution, the relative FL intensity of CDs@MIP decreased linearly with the increasing DA in the concentration range of 25–500nM with a detection limit (3σ) of 1.7nM. Furthermore, the proposed method was successfully intended for the determination of trace DA in human urine samples without the interference of other molecules and ions.
► An eco-friendly CDs@MIP composite was synthesized. ► The synthesis process was a one-pot room-temperature sol–gel polymerization. ► CDs@MIP was the molecular recognition element of fluorescence optosensor. ► The optosensor exhibited high sensitive and selective towards dopamine.
Recently, more and more attention is paid to reversible data hiding (RDH) in encrypted images, since it maintains the excellent property that the original cover can be losslessly recovered after ...embedded data is extracted while protecting the image content's confidentiality. All previous methods embed data by reversibly vacating room from the encrypted images, which may be subject to some errors on data extraction and/or image restoration. In this paper, we propose a novel method by reserving room before encryption with a traditional RDH algorithm, and thus it is easy for the data hider to reversibly embed data in the encrypted image. The proposed method can achieve real reversibility, that is, data extraction and image recovery are free of any error. Experiments show that this novel method can embed more than 10 times as large payloads for the same image quality as the previous methods, such as for PSNR=40 dB.
► We synthesized a novel molecular imprinted polymer based on surface imprinting method. ► The free radical polymerization was occurred at the graphene sheets surface. ► The synthesized polymer ...possesses fast adsorption dynamics and excellent template recognition capacity. ► Therefore, the polymer was applied as a molecular recognition element to construct dopamine electrochemical sensor. ► And this sensor exhibit many outstanding performances.
A novel composite of graphene sheets/Congo red-molecular imprinted polymers (GSCR-MIPs) was synthesized through free radical polymerization (FRP) and applied as a molecular recognition element to construct dopamine (DA) electrochemical sensor. The template molecules (DA) were firstly absorbed at the GSCR surface due to their excellent affinity, and subsequently, selective copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) was further achieved at the GSCR surface. Potential scanning was presented to extract DA molecules from the imprinted polymers film, and as a result, DA could be rapidly and completely removed by this way. With regard to the traditional MIPs, the GSCR-MIPs not only possessed a faster desorption and adsorption dynamics, but also exhibited a higher selectivity and binding capacity toward DA molecule. As a consequence, an electrochemical sensor for highly sensitive and selective detection of DA was successfully constructed as demonstration based on the synthesized GSCR-MIPs nanocomposites. Under experimental conditions, selective detection of DA in a linear concentration range of 1.0×10−7–8.3×10−4M was obtained, which revealed a lower limit of detection and wider linear response compared to some previously reported DA electrochemical MIPs sensors. The new DA electrochemical sensor based on GSCR-MIPs composites also exhibited excellent repeatability, which expressed as relative standard deviation (RSD) was about 2.50% for 30 repeated analyses of 20μM DA.
Background
Trichotillomania (TTM) is a difficult‐to‐treat psychiatric condition with no first‐line medications approved by the Food and Drug Administration. Individuals with TTM often feel that ...clinicians know little about this disorder. Here, we present an updated meta‐analysis of randomized controlled trials (RCTs) examining treatments for TTM.
Methods
Pubmed, PsychINFO, Embase, and CENTRAL were searched with the terms “Trichotillomania OR Hair Pulling Disorder” to identify randomized controlled clinical trials evaluating treatments for TTM.
Results
Twenty‐four trials involving 26 comparisons and 857 participants were included in this meta‐analysis. Behavioral therapy with habit‐reversal training components (BT‐HRT) demonstrated a large benefit compared to control conditions (standardized mean difference SMD 95% CI = −1.22 −1.71, −0.73, p < .0001) for improving TTM symptoms. Clomipramine (SMD 95% CI = −0.71 −1.38, −0.05, p = .036), N‐acetylcysteine (SMD 95% CI = −0.75 −1.36, −0.13, p = .017) and olanzapine (SMD 95% CI = −0.94 −1.77, −0.12, p = .025) demonstrated significant benefits compared to placebo in RCTs.
Conclusions
BT‐HRT has demonstrated the largest treatment effects and has the strongest evidence base for reducing TTM symptoms. In contrast, several pharmacological agents have demonstrated efficacy in single randomized clinical trials that would benefit from replication. Additional trials are needed to identify other effective medications for TTM and determine the relative efficacy of available agents.
Abstract An efficient DNA impedance biosensing platform is constructed, in which positively charged N,N -bis-(1-aminopropyl-3-propylimidazol salt)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) ...is anchored to graphene sheets. The π–π stacking and electronic interactions are elucidated by the distinct absorption features in UV–vis spectra and by quenching perylene fluorescence in contact with graphene. The rational design and tailoring of graphene surface invest it with desired properties (dispersive, structural, photoelectrical and conductive, etc.) and boost its application. Electrostatic interaction between PDI’s positively charged imidazole rings and negatively charged phosphate backbones of single-stranded DNA (ssDNA) facilitates ssDNA immobilization. This manner is different from these mainly based on the attraction between the rings in DNA bases and the hexagonal cells of graphene, which is disturbed after hybridization and causes the leaving of formed double-stranded DNA from graphene surface. The electrostatic ssDNA grafting occupies phosphate backbones and particularly leaves the bases available for efficient hybridization. DNA immobilization and hybridization lead to PDI/graphene interfacial property changes, which are monitored by electrochemical impedance spectroscopy and adopted as the analytical signal. The conserved sequence of the pol gene of human immunodeficiency virus 1 is satisfactorily detected via this PDI/graphene platform and shows high reproducibility, selectivity.
With the rapid development of information technology and the continuous evolution of personalized services, huge amounts of data are accumulated by large internet companies in the process of serving ...users. Moreover, dynamic data interactions increase the intentional/unintentional persistence of private information in different information systems. However, problems such as the cask principle of preserving private information among different information systems and the difficulty of tracing the source of privacy violations are becoming increasingly serious. Therefore, existing privacy-preserving schemes cannot provide systematic privacy preservation. In this paper, we examine the links of the information life-cycle, such as information collection, storage, processing, distribution, and destruction. We then propose a theory of privacy computing and a key technology system that includes a privacy computing framework, a formal definition of privacy computing, four principles that should be followed in privacy computing, algorithm design criteria, evaluation of the privacy-preserving effect, and a privacy computing language. Finally, we employ four application scenarios to describe the universal application of privacy computing, and discuss the prospect of future research trends. This work is expected to guide theoretical research on user privacy preservation within open environments.
Enhanced photocatalytic activities by Au core Novel Au/Cu2ZnSnS4 core/shell nanoparticles (NPs) are synthesized for the first time via wet chemistry approach. The insertion of Au core into CZTS NPs ...dramatically enhances light absorption due to surface plasmon resonance effect, especially in the Vis‐NIR region. Au/CZTS core/shell NPs show much higher photocatalytic activities for hydrogen evolution compared with other CZTS nanostructures.
The effects of substituting Bacillus subtilis, Astragalus membranaceus, and enzymes for aureomycin to improve the growth performance of broilers during specific phases were studied to develop ...alternatives to in-feed antibiotics and decrease drug residues in meat food and antibiotic resistance. Six hundred one-day-old broilers were randomly assigned to 5 groups. Broilers in the control group were supplied with basal diets (CT), and those in the remaining 4 groups were supplied with feed containing aureomycin premix (AU), B. subtilis powder (BS), A. membranaceus root powder (AM), and enzyme compound powder (EN), respectively. Compared to the control group, broilers in the other groups exhibited better growth performance during different phases. Microbial analysis of cecal contents suggested that treatment with BS or EN significantly increased the abundance of Lactobacillus or Bifidobacteria but inhibited Escherichia coli or Clostridium welchii; however, these bacteria were suppressed by AU treatment except C. welchii. The digestibility of the feed in vitro was significantly enhanced by adding BS or EN to the feed, consistent with findings for growth performance. In conclusion, dietary supplementation with 3 additives could improve the growth performance of broilers during specific phases. Future studies should focus on designing suitable schedules to partially replace in-feed antibiotics.
This paper for the first time reports a chemical method to prepare graphene quantum dots (GQDs) from GO. Water soluble and surface unmodified GQDs, serving as a novel, effective and simple ...fluorescent sensing platform for ultrasensitive detection of 2,4,6-trinitrotoluene (TNT) in solution by fluorescence resonance energy transfer (FRET) quenching. The fluorescent GQDs can specifically bind TNT species by the π–π stacking interaction between GQDs and aromatic rings. The resultant TNT bound at the GQDs surface can strongly suppress the fluorescence emission by the FRET from GQDs donor to the irradiative TNT acceptor through intermolecular polar–polar interactions at spatial proximity. The unmodified GQDs can sensitively detect down to ∼0.495ppm (2.2μM) TNT with the use of only 1mL of GQDs solution. The simple FRET-based GQDs reported here exhibit high and stable fluorescence. Eliminating further treatment or modification, this method simplifies and shortens the experimental process. It possesses good assembly flexibility and can thus find many applications in the detection of ultratrace analytes.
► To prepare graphene quantum dots via a chemical method for the first time. ► GQDs showed excellent water soluble and multicolored characterizations. ► GQDs served as a novel, effective and simple fluorescent sensing platform. ► FRET quenching for ultrasensitive detection of TNT.
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