145 research outputs found
Egg white-mediated green synthesis of silver nanoparticles with excellent biocompatibility and enhanced radiation effects on cancer cells
A simple, cost-effective, and environmentally friendly approach to the aqueous-phase synthesis of silver (Ag) nanoparticles was demonstrated using silver nitrate (AgNO3) and freshly extracted egg white. The bio-conjugates were characterized by UV-visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectrometry, and dynamic light scattering. These results indicated that biomolecule-coated Ag nanoparticles are predominantly spherical in shape with an average size of 20 nm. The proteins of egg white, which have different functional groups, played important roles in reducing Ag+ and maintaining product attributes such as stability and dispersity. In vitro cytotoxicity assays showed that these Ag-protein bio-conjugates showed good biocompatibility with mouse fibroblast cell lines 3T3. Furthermore, X-ray irradiation tests on 231 tumor cells suggested that the biocompatible Ag-protein bio-conjugates enhanced the efficacy of irradiation, and thus may be promising candidates for use during cancer radiation therapy
NaCl-induced hot corrosion behaviors of NiSiAlY coatings
In the marine environments, NiCrAlY coatings with high content of Cr would suffer much severer corrosion due to the effect of NaCl. Thus, NiSiAlY coatings with different Si content were proposed and deposited on Ni-based superalloys by multi-arc ion plating. The as-deposited coating was mainly composed of γ’-Ni3Al phase with a small amount of β-NiAl phase. NaCl-induced hot corrosion tests were performed on the coatings at 500°C, 600°C, and 700°C, respectively. Compared with Ni-based alloy substrates, the NiSiAlY coatings exhibited a good corrosion resistance to NaCl at elevated temperatures. However, with an excessive amount of Si, the NiSiAlY coating showed a degradation in the hot corrosion resistance. In this work, the corrosion mechanisms of the tested coatings were discussed. Moreover, the role of Si was also investigated
Strategy for evaluating the status of relay protection equipment for the new generation of intelligent substations
With the rapid development of power grid, the structure and technology of the secondary system in substations are also constantly innovating. The new generation of intelligent substations has achieved online monitoring functions for secondary equipment, making some state variables of relay protection equipment become observable indicators. Based on this, this paper proposes a novel relay protection equipment status evaluation strategy. Firstly, considering the fuzziness and uncertainty of the boundary division of relay protection evaluation levels, a relay protection risk assessment method based on normal cloud model has been proposed. Then, due to the particularity of historical statistical data, a weight calculation method combining analytical hierarchy process (AHP) and entropy weight method is adopted to eliminate subjective factors in the weight calculation process. Meanwhile, the equipment operation risk level was determined by calculating the certainty of the corresponding evaluation level for each indicator. Finally, in case study, the proposed method is used to evaluate the status of relay protection equipment, and the feasibility and accuracy of this method are verified through the analysis of the results
A Rapid Method for Detection of Salmonella in Milk Based on Extraction of mRNA Using Magnetic Capture Probes and RT-qPCR
Magnetic separation is an efficient method for target enrichment and elimination of inhibitors in the molecular detection systems for foodborne pathogens. In this study, we prepared magnetic capture probes by modifying oligonucleotides complementary to target sequences on the surface of amino-modified silica-coated magnetic nanoparticles and optimized the conditions and parameters of probe synthesis and hybridization. We innovatively put the complexes of magnetic capture probes and target sequences into qPCR without any need for denaturation and purification steps. This strategy can reduce manual steps and save time. We used the magnetic capture probes to separate invA mRNA from Salmonella in artificially contaminated milk samples. The detection sensitivity was 104Â CFU/ml, which could be increased to 10Â CFU/ml after a 12Â h enrichment step. The developed method is robust enough to detect live bacteria in a complex environmental matrix
Observation of room-temperature ferroelectricity in elemental Te nanowires
Ferroelectrics are essential in low-dimensional memory devices for multi-bit
storage and high-density integration. A polar structure is a necessary premise
for ferroelectricity, mainly existing in compounds. However, it is usually rare
in elemental materials, causing a lack of spontaneous electric polarization.
Here, we report an unexpected room-temperature ferroelectricity in few-chain Te
nanowires. Out-of-plane ferroelectric loops and domain reversal are observed by
piezoresponse force microscopy. Through density functional theory, we attribute
the ferroelectricity to the ion-displacement created by the interlayer
interaction between lone pair electrons. Ferroelectric polarization can induce
a strong field effect on the transport along the Te chain, supporting a
self-gated field-effect transistor. It enables a nonvolatile memory with high
in-plane mobility, zero supply voltage, multilevel resistive states, and a high
on/off ratio. Our work provides new opportunities for elemental ferroelectrics
with polar structures and paves a way towards applications such as low-power
dissipation electronics and computing-in-memory devices
The Effect of 6-Week Combined Balance and Plyometric Training on Change of Direction Performance of Elite Badminton Players
The study aimed to investigate the effect of combined balance and plyometric training on the change of direction (COD) performance of badminton athletes. Sixteen elite male badminton players volunteered to participate and were randomly assigned to a balance-plyometric group (BP: n = 8) and plyometric group (PL: n = 8). The BP group performed balance combined with plyometric training three times a week over 6 weeks; while the PL group undertook only plyometric training three times a week during the same period. Meanwhile, both groups were given the same technical training. All participants were tested to assess the COD ability before and after the training period: Southeast Missouri (SEMO) test and 5-0-5 test, dynamic balance ability (Y-Balance test, YBT), and reactive strength index (RSI). Repeated-measure ANOVA revealed that after the intervention there was a significant time × group interaction for 5-0-5 COD test, YBT of both legs and RSI (p < 0.05, partial η2 = 0.26–0.58) due to the better performance observed at post-test compared with a pre-test for the BP group [effect size (ES) = 1.20–1.76], and the improvement was higher than that of the PL group. The change in SEMO test did not differ between BP and PL (p < 0.159, partial η2= 0.137), but the magnitude of the with-group improvement for BP (ES = 1.55) was higher than that of PL (ES = 0.81). These findings suggest that combined training could further improve the COD performance of badminton athletes than plyometric training alone and might provide fitness trainers a more efficient COD training alternative
Stress-Induced Epinephrine Enhances Lactate Dehydrogenase A and Promotes Breast Cancer Stem-Like Cells
Chronic stress triggers activation of the sympathetic nervous system and drives malignancy. Using an immunodeficient murine system, we showed that chronic stress–induced epinephrine promoted breast cancer stem-like properties via lactate dehydrogenase A–dependent (LDHA-dependent) metabolic rewiring. Chronic stress–induced epinephrine activated LDHA to generate lactate, and the adjusted pH directed USP28-mediated deubiquitination and stabilization of MYC. The SLUG promoter was then activated by MYC, which promoted development of breast cancer stem-like traits. Using a drug screen that targeted LDHA, we found that a chronic stress–induced cancer stem-like phenotype could be reversed by vitamin C. These findings demonstrated the critical importance of psychological factors in promoting stem-like properties in breast cancer cells. Thus, the LDHA-lowering agent vitamin C can be a potential approach for combating stress-associated breast cancer
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