A potential platform for simultaneous anticancer drug delivery and MRI cell imaging has been demonstrated by uniform hollow inorganic core/shell structured multifunctional mesoporous nanocapsules, ...which are composed of functional inorganic (Fe3O4, Au, etc.) nanocrystals as cores, a thin mesoporous silica shell, and a huge cavity in between. The synthetic strategy for the creation of huge cavities between functional core and mesoporous silica shell is based on a structural difference based selective etching method, by which solid silica middle layer of Fe2O3@SiO2@mSiO2 (or Au@SiO2@mSiO2) composite nanostructures was selectively etched away while the mesoporous silica shell could be kept relatively intact. The excellent biocompatibility of obtained multifunctional nanocapsules (Fe3O4@mSiO2) was demonstrated by very low cytotoxicity against various cell lines, low hemolyticity against human blood red cells and no significant coagulation effect against blood plasma. The cancer cell uptake and intracellular location of the nanocapsules were observed by confocal laser scanning microscopy and bio-TEM. Importantly, the prepared multifunctional inorganic mesoporous nanocapsules show both high loading capacity (20%) and efficiency (up to 100%) for doxorubicin simultaneously because of the formation of the cavity, enhanced surface area/pore volume and the electrostatic interaction between DOX molecules and mesoporous silica surface. Besides, the capability of Fe3O4@mSiO2 nanocapsules as contrast agents of MRI was demonstrated both in vitro and in vivo, indicating the simultaneous imaging and therapeutic multifunctionalities of the composite nanocapsules. Moreover, the concept of multifunctional inorganic nanocapsules was extended to design and prepare Gd−Si−DTPA grafted Au@mSiO2 nanocapsules for nanomedical applications, further demonstrating the generality of this strategy for the preparation of various multifunctional mesoporous nanocapsules.
Attribute-Based Encryption (ABE) is a promising cryptographic primitive which significantly enhances the versatility of access control mechanisms. Due to the high expressiveness of ABE policies, the ...computational complexities of ABE key-issuing and decryption are getting prohibitively high. Despite that the existing Outsourced ABE solutions are able to offload some intensive computing tasks to a third party, the verifiability of results returned from the third party has yet to be addressed. Aiming at tackling the challenge above, we propose a new Secure Outsourced ABE system, which supports both secure outsourced key-issuing and decryption. Our new method offloads all access policy and attribute related operations in the key-issuing process or decryption to a Key Generation Service Provider (KGSP) and a Decryption Service Provider (DSP), respectively, leaving only a constant number of simple operations for the attribute authority and eligible users to perform locally. In addition, for the first time, we propose an outsourced ABE construction which provides checkability of the outsourced computation results in an efficient way. Extensive security and performance analysis show that the proposed schemes are proven secure and practical.
Electrospinning provides an enabling nanotechnology platform for generating a rich variety of novel structured materials in many biomedical applications including drug delivery, biosensing, tissue ...engineering, and regenerative medicine. In this review article, we begin with a thorough discussion on the method of producing 1D, 2D, and 3D electrospun nanofiber materials. In particular, we emphasize on how the 3D printing technology can contribute to the improvement of traditional electrospinning technology for the fabrication of 3D electrospun nanofiber materials as drug delivery devices/implants, scaffolds or living tissue constructs. We then highlight several notable examples of electrospun nanofiber materials in specific biomedical applications including cancer therapy, guiding cellular responses, engineering in vitro 3D tissue models, and tissue regeneration. Finally, we finish with conclusions and future perspectives of electrospun nanofiber materials for drug delivery and regenerative medicine.
This review summarizes the methods for producing 1D electrospun fragment, 1D nanofiber bundles, 2D nanofiber membranes, and 3D nanofiber scaffolds. Next, the combination of electrospinning with 3D printing, flexible electrode, and microfluidcs are discussed. And the review highlights the biomedical applications of nanofiber scaffolds, including drug delivery, controlling cellular behaviors, engineering in vitro 3D tissue/tumor models, and regenerative medicine. Display omitted
An easy bottom–up method for the preparation of photoluminescent (PL) graphene quantum dots (GQDs) and graphene oxide (GO) has been developed by tuning the carbonization degree of citric acid and ...dispersing the carbonized products into alkaline solutions. The GQDs are nanosheets ∼15nm in width, and 0.5–2.0nm in thickness. They show a relatively strong (9.0%) PL quantum yield and an excitation-independent PL emission activity. In contrast, the GO nanostructures consist of sheets that are hundreds of nanometers in width and ∼1nm in height. They exhibit a relatively weak (2.2%) PL quantum yield and an excitation-dependent PL emission activity.
Extracting road networks from very-high-resolution (VHR) aerial and satellite imagery has been a long-standing problem. In this article, a neural-dynamic tracking framework is proposed to extract ...road networks based on deep convolutional neural networks (DNN) and a finite state machine (FSM). Inspired by autonomous mobile systems, the authors train a DNN to recognize the pattern of input data, which is an image patch extracted in a detection window centred at the current location of the tracker. The pattern is predefined according to the environment and associated with the states in the FSM. A vector-guided sampling method is proposed to generate the training data set for the DNN, which extracts massive image-direction pairs from the imagery and existing vector road maps. In the tracking procedure, the size of the detection window is determined by a fusion strategy and the extracted image patches represent the orientation features of the road (local environment) that can be recognized by the trained DNN. The reactive unit in FSM associates states with behaviours of the tracker while continually modifying the orientation to follow the road and generating a sequence of states and locations. In this way, our framework combines the DNN and FSM. DNN acts as a key component to recognize patterns from a complex and changing environment; FSM translates the recognized patterns to states and controls the behaviour of the tracker. The results illustrate that our approach is more accurate and efficient than the traditional ones.
Mounting environmental pressures led China to focus on the effectiveness of the environmental regulation to control pollution. Since the shadow economy, or underground economic activities that are ...not included in official statistics, accounts for an increasing fraction of China's economy, its impacts on environmental quality should be carefully evaluated. In this study, the main research questions are as follows: 1) What is the extent of the effect of environmental regulation on environmental quality? and 2) What are the factors that influence the impact of environmental regulation on environmental pollution? A theoretical model is developed to explain the relationship among the environmental regulation, shadow economy, and environmental quality in China. An empirical analysis is conducted to test the three propositions of the model, thereby examining the explanatory power of the theoretical model. Concretely, using panel data from 30 provinces for the period of 1998–2012, the generalized method of moments (GMM) method is employed to control for potential endogeneity and introduce dynamic effects. The estimation results indicate that stringent environmental regulation and the level of the shadow economy are both positively related to China's environmental pollution; however, the results also indicate that tighter environmental control would help reduce pollution at a given level of the shadow economy. Moreover, an increase in the proportion of corrupt officials may weaken the environmental regulation, which would consequently lead to the increase in illegal production and total pollutant emissions. Besides, many economic and social factors may also affect the environmental quality. For instance, the development of secondary industry contributes toward an increase in pollutant emissions; however, increased research and development (R&D) spending on eco-friendly industrial operations can help to reduce pollution.
•Impact of environmental regulation, shadow economy and corruption on the environment is examined.•A theoretical model is built to explain the relationship.•Three propositions of the theoretical model are empirically tested.•Levels of environmental regulation and shadow economy are positively related with pollution.•Environmental regulation is effective only when shadow economy and corruption are controlled.
We recognized 6 sets of reflecting P- and S-wave events from Moho and other interfaces within the crust, respectively, with the wide-angle seismic data acquired from 510 km-long Selincuo-Ya'anduo ...profile in the northern Tibet, fitted the observed events with forward modeling, and interpreted crustal structure of P- and S-wave velocities and Poisson's ratio under the profile. The results demonstrate that the crustal structure between Yarlungzangbo and Bangong-Nujiang sutures changes abruptly, and the crust is the thickest at the middle part of the profile with thickness of 80 km or more. The "down-bowing" Moho is the striking feature for the crustal variation along the west-east direction. The Moho uplifts with steps, and the uplifting rate westward is greater than that eastward. The heterogeneity of P- and S-wave velocities exists both vertically and horizontally, and one lower velocity layer (LVL) exists with the depth range of 27-34 km and the thickness range of 5-7 km. For the upper crust, Poisson's ratio is the lowest at the middle part of the profile; for the lower crust, the Poisson's ratio at the east segment is lower than that at west segment, which means that the crustal rigidity for the upper crust is different from the lower crust, and the lower crust under the east segment of the profile is more ductile. We infer that the substance in the lower crust endured eastward flow along with the collision between Eurasian and Indian plates, and the "down-bowing" Moho is attributable to the multi-phase E-W tectonic processes.
Abstract
Background
Deregulated circular RNAs (circRNAs) are associated with the development of cancer and therapy resistance. However, functional research of circRNAs mostly focus on potential miRNA ...or protein binding and more potential regulation of circRNA on host gene DNA in cancers are yet to be inspected.
Method
We performed total RNA sequencing on clinical breast cancer samples and identified the expression patterns of circRNAs and corresponding host genes in patient blood, tumor and adjacent normal tissues. qPCR, northern blot and in situ hybridization were used to validate the dysregulation of circRNA circSMARCA5. A series of procedures including R-loop dot-blotting, DNA-RNA immunoprecipitation and mass spectrum, etc. were conducted to explore the regulation of circSMARCA5 on the transcription of exon 15 of SMARCA5. Moreover, immunofluorescence and in vivo experiments were executed to investigate the overexpression of circSMARCA5 with drug sensitivities.
Results
We found that circRNAs has average higher expression over its host linear genes in peripheral blood. Compared to adjacent normal tissues, circSMARCA5 is decreased in breast cancer tissues, contrary to host gene SMARCA5. The enforced expression of circSMARCA5 induced drug sensitivity of breast cancer cell lines in vitro and in vivo. Furthermore, we demonstrated that circSMARCA5 can bind to its parent gene locus, forming an R-loop, which results in transcriptional pausing at exon 15 of SMARCA5. CircSMARCA5 expression resulted in the downregulation of SMARCA5 and the production of a truncated nonfunctional protein, and the overexpression of circSMARCA5 was sufficient to improve sensitivity to cytotoxic drugs.
Conclusion
Our results revealed a new regulatory mechanism for circRNA on its host gene and provided evidence that circSMARCA5 may serve as a therapeutic target for drug-resistant breast cancer patients.
Bio-catalytic degradation of recalcitrant micropollutants with enzymes such as laccase provides an environmentally attractive alternative to the conventional filtration and adsorption processes. ...However, enzyme loss and denaturation remain key challenges for their potential use in water treatment applications. In this work, laccase immobilization on TiO2 nanoparticles and TiO2 blended polyethersulfone (PES) membranes were investigated due to TiO2's chemical stability, ease of functionalization, and architecture. Different surface modification and functionalization strategies on support materials were compared based on enzyme loading, apparent activity, activity recovery, and stability. When coupling agent 3-aminopropyltriethoxysilane (APTES) and cross-linker glutaraldehyde (GLU) were applied sequentially, effective coupling of laccase was achieved based on 2,2′-azino-bis-(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS) assays. TiO2 functionalized PES membrane showed better enzyme immobilization efficiency than the non-functionalized membrane. Optimal performance was observed for PES membrane containing 4wt% TiO2, where TiO2 not only provided the enzyme coupling sites but also affected the membrane surface morphology and hydrophilicity to favor the enzyme immobilization. These bio-catalytic membranes also displayed good enzyme stability, tolerance to wider pH range and vigorous filtration conditions required for water treatment applications. Kinetic study also indicated that the enzyme affinity to assay substrate was maintained after immobilization when compared with packed bed and batch reactors.
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•Laccase is immobilized on TiO2 nanoparticles and TiO2 functionalized membranes.•TiO2 loading has significant effect on bio-catalytic membrane performance.•Bio-catalytic membrane stability is mainly determined by immobilization technique.•Laccase on membrane has higher affinity to ABTS than batch and packed bed reactors.
Developing nonprecious hydrogen evolution electrocatalysts that can work well at large current densities (e.g., at 1000 mA/cm2: a value that is relevant for practical, large-scale applications) is of ...great importance for realizing a viable water-splitting technology. Herein we present a combined theoretical and experimental study that leads to the identification of α-phase molybdenum diboride (α-MoB2) comprising borophene subunits as a noble metal-free, superefficient electrocatalyst for the hydrogen evolution reaction (HER). Our theoretical finding indicates, unlike the surfaces of Pt- and MoS2-based catalysts, those of α-MoB2 can maintain high catalytic activity for HER even at very high hydrogen coverage and attain a high density of efficient catalytic active sites. Experiments confirm α-MoB2 can deliver large current densities in the order of 1000 mA/cm2, and also has excellent catalytic stability during HER. The theoretical and experimental results show α-MoB2’s catalytic activity, especially at large current densities, is due to its high conductivity, large density of efficient catalytic active sites and good mass transport property.
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