Titanium dioxide nanoparticles (TiO2 NPs) are one of the most widely used nanomaterials in the consumer products, agriculture, and energy sectors. Their large demand and widespread applications will ...inevitably cause damage to organisms and ecosystems. A better understanding of TiO2 NP toxicity in living organisms may promote risk assessment and safe use practices of these nanomaterials. This review summarizes the toxic effects of TiO2 NPs on multiple taxa of microorganisms, algae, plants, invertebrates, and vertebrates. The mechanism of TiO2 NP toxicity to organisms can be outlined in three aspects: The Reactive Oxygen Species (ROS) produced by TiO2 NPs following the induction of electron–hole pairs; cell wall damage and lipid peroxidation of the cell membrane caused by NP-cell attachment by electrostatic force owing to the large surface area of TiO2 NPs; and TiO2 NP attachment to intracellular organelles and biological macromolecules following damage to the cell membranes.
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In recent years, a chaotic system is considered as an important pseudo-random source to pseudo-random number generators (PRNGs). This paper proposes a PRNG based on a modified logistic chaotic ...system. This chaotic system with fixed system parameters is convergent and its chaotic behavior is analyzed and proved. In order to improve the complexity and randomness of modified PRNGs, the chaotic system parameter denoted by floating point numbers generated by the chaotic system is confused and rearranged to increase its key space and reduce the possibility of an exhaustive attack. It is hard to speculate on the pseudo-random number by chaotic behavior because there is no statistical characteristics and infer the pseudo-random number generated by chaotic behavior. The system parameters of the next chaotic system are related to the chaotic values generated by the previous ones, which makes the PRNG generate enough results. By confusing and rearranging the output sequence, the system parameters of the previous time cannot be gotten from the next time which ensures the security. The analysis shows that the pseudo-random sequence generated by this method has perfect randomness, cryptographic properties and can pass the statistical tests.
Aptamers are oligonucleotide sequences with a length of about 25–80 bases which have abilities to bind to specific target molecules that rival those of monoclonal antibodies. They are attracting ...great attention in diverse clinical translations on account of their various advantages, including prolonged storage life, little batch-to-batch differences, very low immunogenicity, and feasibility of chemical modifications for enhancing stability, prolonging the half-life in serum, and targeted delivery. In this Review, we demonstrate the emerging aptamer discovery technologies in developing advanced techniques for producing aptamers with high performance consistently and efficiently as well as requiring less cost and resources but offering a great chance of success. Further, the diverse modifications of aptamers for therapeutic applications including therapeutic agents, aptamer–drug conjugates, and targeted delivery materials are comprehensively summarized.
The accuracy of InSAR in monitoring mining surface subsidence is always a matter of concern for surveyors. Taking a mining area in Shandong Province, China, as the study area, D-InSAR and SBAS-InSAR ...were used to obtain the cumulative subsidence of a mining area over a multi-period, which was compared with the mining progress of working faces. Then dividing the mining area into regions with different magnitudes of subsidence according to the actual mining situation, the D-InSAR-, SBAS-InSAR- and leveling-monitored results of different subsidence magnitudes were compared and the Pearson correlation coefficients between them were calculated. The results show that InSAR can accurately detect the location, range, spatial change trend, and basin edge information of the mining subsidence. However, InSAR has insufficient capability to detect the subsidence center, having high displacement rates, and its monitored results are quite different from those of leveling. To solve this problem, the distance from each leveling point to the subsidence center was calculated according to the layout of the rock movement observation line. Besides, the InSAR-monitored error at each leveling point was also calculated. Then, according to the internal relationship between these distances and corresponding InSAR-monitored errors, a correction model of InSAR-monitored results was established. Using this relationship to correct the InSAR-monitored results, results consistent with the actual situation were obtained. This method effectively makes up for the deficiency of InSAR in monitoring the subsidence center of a mining area.
The core of urbanization is land use change, resulting in the urban sprawl and urban population explosion. The problem of land resources shortage and ecological environment destruction has become ...increasingly prominent. Land use change and human activities can directly lead to urban soil pollution. This study analyzed the concentration of Cd, Cr, Cu, Ni, Pb, Zn, Hg and As in the original site of Xi'an chlor-alkali chemical plant, which was know as a brownfield. The results showed the concentrations of Hg, Pb and Zn in research areas were obviously higher than soil background value. Through pollution index (PI) method and Geo-accumulation Index (Igeo) method, totally 26 sample points in different areas (A, B, C, D) were classified into different pollution degrees. The CPI results indicated 9 sample points were heavily polluted, accounting for 34.6% of the total. Among them, 6 out of 9 were located in area A. 12 samples points were not polluted. The average Igeo values of single heavy metal were arranged in the order of Hg (1.83) > Zn (1.26) > Pb (0.33). The pollution of Hg was relatively serious and extensive, especially in area A. It was mainly because of the historical pollution produced by chemical plant. The pollution of Pb in each point was quite different. Mainly influenced by automobile related activities, Igeo(Pb) in sample point 15 and 16 were all beyond 4.00. The average potential ecological risk (PER) of each area was in the order of A (1428) > B (297) > D (249) > C (163). The ecological risk was mainly determined by previous industrial production and present human activity at the same time. People and land are interdependent and interactive. The understanding on the mechanism of man-land interralations, regarding to urban land use and ecological environment, will promote urban sustainability.
There are potential opportunistic risks in the partnerships of enterprises in different industries. Asymmetric information, incomplete decision-making and Human bounded rationality are factors for ...the formation of opportunistic risks, and adopting external governance is a feasible way to defuse the risks. Supply chain governance is a new type of governance which is different from enterprise governance. Its scope of governance is wider than enterprise governance. It is the performance of environmental evolution and organizational innovation. Based on the incomplete contract, this paper analyzes the game between the supplier and the manufacturer. It is found that in the process of the game, the cooperation benefits of both parties are the largest and the distribution of benefits is the fairest. Therefore, combined with the theory of supply chain governance, this paper hopes to maximize the value of supply chain by optimizing the supply chain governance strategy under the condition of incomplete contract.
Chlorpyrifos is a type of organophosphate insecticide used extensively in the plantation of tomatoes, a worldwide popular food. However, chlorpyrifos residues on tomatoes bring risks to human health ...considering the consumption level of tomato is relatively high across many countries. Accurate detection and strict regulation of chlorpyrifos residues are very important in controlling health risks related to chlorpyrifos. Therefore, we developed a rapid, highly sensitive, economical, and nondestructive surface-enhanced Raman spectroscopy (SERS)-based method that can quantitatively determine the content of chlorpyrifos in tomatoes. Silver colloid was optimized and used as the enhance substrate for SERS. Chlorpyrifos residues on tomato surface and in tomato extract were both measured with SERS, and the results acquired under these practical conditions well matched those of chlorpyrifos standard solutions. Linear relationships between chlorpyrifos concentrations and SERS intensities at crucial characteristic peaks under both conditions were established, and the results showed linearity across the entire measured range from 10
−3
to 10
−9
mol L
−1
. The detection limit of the proposed method was 10
−9
mol L
−1
, which was much lower than the standards of chlorpyrifos use for China, Japan and EU, and was the lowest reported concentration chlorpyrifos had been measured on any fruit/vegetable surface or in its extract. The proposed method was very promising in the accurate, quantitative detection of pesticide residues, and it may be adapted to a variety of agricultural products and other areas in food science.
Parkinson's disease (PD) remains one of the most common neurodegenerative movement disorders with limited treatment options available. A dopamine derivative N-3,4-bis(pivaloyloxy)-dopamine (BPD) ...previously developed in our group has demonstrated superior therapeutic outcome compared to levodopa in a PD mice model. To further improve the therapeutic performance of BPD, a brain targeted drug delivery system was designed using a 29 amino-acid peptide (RVG29) derived from rabies virus glycoprotein as the targeting ligand. RVG29 functionalized liposomes (RVG29-lip) showed significantly higher uptake efficiency in murine brain endothelial cells and dopaminergic cells, and high penetration efficiency across the blood brain barrier (BBB) in vitro. In vivo and ex vivo distribution studies demonstrated RVG29-lip selectively distributed to the brain, striatum and substantia nigra. Furthermore, BPD loaded RVG29-lip (BPD-RVG29-lip) exhibited improved therapeutic efficacy in a PD mouse model, while causing no obvious systemic toxicity after intravenous administration. Thus, BPD-RVG29-lip represents a highly promising approach for the brain targeted treatment of PD.
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•It’s the first time to design a brain targeted drug delivery system using dopamine derivative BPD for the treatment of PD;•The application of a brain targeted drug delivery system has improved the therapeutic performance of BPD;•The findings provide novel insights into the solutions to the druggability of small molecule drugs.•For the first time, RVG29 was used as a dual-targeting ligand for the treatment of PD.
Body fat distribution is a well-established predictor of adverse medical outcomes, independent of overall adiposity. Studying body fat distribution sheds insights into the causes of obesity and ...provides valuable information about the development of various comorbidities. Compared to total adiposity, body fat distribution is more closely associated with risks of cardiovascular diseases. The present review specifically focuses on the sexual dimorphism in body fat distribution, the biological clues, as well as the genetic traits that are distinct from overall obesity. Understanding the sex determinations on body fat distribution and adiposity will aid in the improvement of the prevention and treatment of cardiovascular diseases (CVD).
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