Analysis of the Main Factors Influencing the Dominant Frequency of Blast Vibration

At present, the study on the dominant frequency of blasting vibration is still a worldwide problem. Compared with the mature research on the particle peak velocity of blasting vibration, the researches on the dominant frequency of blasting vibration are much less. In this paper, by analyzing the main influencing factors of the dominant frequency, an attenuation equation of the dominant frequency induced by blasting vibration has been proposed by dimensional analysis combined with the theory of radial spherical wave propagation. The proposed equation is applied to the fitting analysis on the dominant frequency measured in Zhoushan Green Petrochemical Base in China, which has obtained a favorable fitting correlation. Based on the fitting analysis, it has found that the correlation coefficient of radial vibration obtained by the proposed equation is higher than that of vertical vibration, which is resulted from the reason that the vibration in vertical is considered to be influenced most by the R-wave on the ground and perceived to be quite different from the radial vibration affected by P-wave. In generally, different components of blasting waves will affect the attenuation of dominant frequency

Superhydrophobic Shape Memory Polymer Arrays with Switchable Isotropic/Anisotropic Wetting

Smart surfaces with tunable wettability have aroused much attention in the past few years. However, to obtain a surface that can reversibly transit between the lotus-leaf-like superhydrophobic isotropic and rice-leaf-like superhydrophobic anisotropic wettings is still a challenge. This paper, by mimicking microstructures on both lotus and rice leaves, reports such a surface that is prepared by creating micro/nanostructured arrays on the shape memory polymer. On the surface, the microstructure shapes can be reversibly changed between the lotus-leaf-like random state and the rice-leaf-like 1D ordered state. Accordingly, repeated switch between the superhydrophobic isotropic and anisotropic wettings can be displayed. Research results indicate that the smart controllability is ascribed to the excellent shape memory effect of the polymer, which endows the surface with special ability in memorizing different microstructure shapes and wetting properties. Meanwhile, based on the smart wetting performances, the surface is further used as a rewritable functional platform, on which various droplet transportation programmes are designed and demonstrated. This work reports a superhydrophobic surface with switchable isotropic/anisotropic wettings, which not only provides a novel functional material but also opens a new avenue for application in controlled droplet transportation

Controllable Drug Release System in Living Cells Triggered by Enzyme–Substrate Recognition

Vehicles can deliver the drug molecules into cells, yet immunoreaction of the commonly used capping agents and release triggers limit their biomedical use. This shortcoming might be circumvented through replacing these chemicals with certain biomolecules. Here, we show a new and facile way to encapsulate the drug delivery vehicles and release the cargos in a highly controllable manner via modulating supramolecular interactions between enzyme, substrate, and vehicle. The cargo release from the vehicles within cells can be achieved upon substrate treatment. Yeast cells were used, allowing for a fast and cost-effective way for imaging and morphological analysis. We believe this new platform can be readily extended to various carrier systems for different purposes based on shifting the recognition pattern of enzyme–substrate pairs

Homocysteine level of Tibetan population settled down at different altitudes

Objective To investigate and analyze the level of homocysteine (Hcy) in Tibet and to analyze the differences of Hcy level in different altitude regions, genders and ages, and thus to provide the prevalence profile of hyperhomocysteine and the differences in relevant tests between HHcy(hyperhomocysteinemia) and non-HHcy populations. Methods Totally 1 615(male n=585) subjects were selected from Ngari, Lhasa, Shigatse and Nyingchi plateau areas of Tibet by stratified cluster sampling. Serum Hcy level was analyzed and the difference of Hcy level in populations located at different altitude plateau areas, gender groups were found. The prevalence of hyperhomocysteine and related test were analyzed. Kruskal Wallis test was used to compare Hcy levels in different altitudes, genders and age groups, and Pearson Chi-square test was used to compare HHcy prevalence. Variance analysis was used for the differences of different test indicators between non-HHcy and HHcy populations. Results The level of Hcy in different regions and different genders were statistically significant, which was higher in males than that in females, and higher in Lhasa and Shigatse than in Nyingchi and Ngari. There was difference in serum HHcy prevalence among different genders, regions and age groups. Males showed a higher level than females, people from Lhasa and Shigatse showed a higher level than those from Nyingchi and Ngari. Conclusions The incidence of hyperhomocysteinemia in Tibet is statistically significant in different areas, different genders and different age groups. So this study provides a scientific basis for the rational use of Hcy as an indicator in clinical practice of prevention and treatment of related diseases in plateau areas

DNA–Carbon Dots Function as Fluorescent Vehicles for Drug Delivery

Carbon dots (CDs) are a new representative in the carbon-based material family, attracting tremendous interest in a large variety of fields, including biomedicine. In this report, we described a facile and green system for synthesizing DNA–CDs using genomic DNA isolated from <i>Escherichia coli</i>. DNA–CDs can be purified using a simple column centrifugation-based system. During DNA–CD synthesis, ribose was collapsed, accompanied by the release of nitrogen, and several new bonds (C–OH, N–O, and N–P) were formed, while the other covalent bonds of DNA were largely maintained. The presence of abundant chemical groups, such as amino or hydroxyl groups on DNA–CDs, may facilitate their future functionalization. These highly biocompatible DNA–CDs can serve as a new type of fluorescent vehicle for cell imaging and drug delivery studies. Our research may hasten the development of CDs for prominent future biomedical applications

Protein–Gold Hybrid Nanocubes for Cell Imaging and Drug Delivery

Multifunctional biocompatible nanomaterials containing both fluorescent and vehicle functions are highly favored in bioimaging, therapeutic, and drug delivery applications. Nevertheless, the rational design and synthesis of highly biocompatible multifunctional materials remain challenging. We present here the development of novel protein–gold hybrid nanocubes (PGHNs), which were assembled using gold nanoclusters, bovine serum albumin, and tryptophan as building blocks. The green-synthesized PGHNs in this study are blue-emitting under UV exposure and cube-shaped with a size of approximately 100 nm. These hybrid nanomaterials are highly biocompatible as shown by cytotoxicity experiments and can be readily internalized by different types of cells. Moreover, PGHNs can act as nanovehicles that successfully deliver dyes or drugs into the cells. The protein–metal hybrid nanocubes can serve as a new type of dual-purpose tool: a blue-emitting cell marker in bioimaging investigation and a nanocarrier in drug delivery studies