Cell Membrane Oscillations under Radiofrequency Electromagnetic Modulation.

Cell responses to external radiofrequencies (RF) are a fundamental problem of much scientific research, clinical applications, and even daily lives surrounded by wireless communication hardware. In this work, we report an unexpected observation that the cell membrane can oscillate at the nanometer scale in phase with the external RF radiation from kHz to GHz. By analyzing the oscillation modes, we reveal the mechanism behind the membrane oscillation resonance, membrane blebbing, the resulting cell death, and the selectivity of plasma-based cancer treatment based on the difference in the membrane's natural frequencies among cell lines. Therefore, a selectivity of treatment can be achieved by aiming at the natural frequency of the target cell line to focus the membrane damage on the cancer cells and avoid normal tissues nearby. This gives a promising cancer therapy that is especially effective in the mixing lesion of the cancer cells and normal cells such as glioblastoma where surgical removal is not applicable. Along with these new phenomena, this work provides a general understanding of the cell coupling with RF radiation from the externally stimulated membrane behavior to the cell apoptosis and necrosis.

A Thermal Infrared Pedestrian-Detection Method for Edge Computing Devices.

The thermal imaging pedestrian-detection system has excellent performance in different lighting scenarios, but there are problems regarding weak texture, object occlusion, and small objects. Meanwhile, large high-performance models have higher latency on edge devices with limited computing power. To solve the above problems, in this paper, we propose a real-time thermal imaging pedestrian-detection method for edge computing devices. Firstly, we utilize multi-scale mosaic data augmentation to enhance the diversity and texture of objects, which alleviates the impact of complex environments. Then, the parameter-free attention mechanism is introduced into the network to enhance features, which barely increases the computing cost of the network. Finally, we accelerate multi-channel video detection through quantization and multi-threading techniques on edge computing devices. Additionally, we create a high-quality thermal infrared dataset to facilitate the research. The comparative experiments on the self-built dataset, YDTIP, and three public datasets, with other methods show that our method also has certain advantages.

Cold Plasma Discharge Tube Enhances Antitumoral Efficacy of Temozolomide.

Glioblastoma (GBM) is a fatal human brain tumor with a low survival rate. Temozolomide (TMZ) has been widely used in GBM therapy with noticeable side effects. Cold plasma is an ionized gas that is generated near room temperature. Here, we demonstrated the enhancement therapeutic efficacy of TMZ via using a cold plasma source based on nonequilibrium plasma in a sealed glass tube, named a radial cold plasma discharge tube (PDT). The PDT affected glioblastoma cells' function just by its electromagnetic (EM) emission rather than any chemical factors in the plasma. The PDT selectively increased the cytotoxicity of TMZ on two typical glioblastoma cell lines, U87MG and A172, compared with normal astrocyte cell line hTERT/E6/E7 to some extent. Furthermore, on the basis of a patient-derived xenograft model, our preliminary in vivo studies demonstrated the drastically improved mean survival days of the tumor-barrier mice by more than 100% compared to control. The PDT is not only independent of continuous helium supply but is also capable of resisting the interference of environmental changes. Thus, the PDT was a stable and low-cost cold atmospheric plasma source. In short, this study is the first to demonstrate the promising application of PDTs in GBM therapy as a noninvasive and portable modality.

Anti-Melanoma Capability of Contactless Cold Atmospheric Plasma Treatment.

In this study, we demonstrated that the widely used cold atmospheric plasma (CAP) jet could significantly inhibit the growth of melanoma cells using a contactless treatment method, The flow rate of helium gas was a key operational parameter to modulate electromagnetic (EM) effect on melanoma cells. Metal sheets with different sizes could be used as a strategy to control the strength of EM effect. More attractive, the EM effect from CAP could penetrate glass/polystyrene barriers as thick as 7 mm. All these discoveries presented the profound non-invasive nature of a physically based CAP treatment, which provided a solid foundation for CAP-based cutaneous/subcutaneous tumor therapy.

Random Mutagenesis by Insertion of Error-Prone PCR Products to the Chromosome of Bacillus subtilis.

Bacillus subtilis is an attractive host for the directed evolution of the enzymes whose substrates cannot be transported across cell membrane. However, the generation of a mutant library in B. subtilis suffers problems of small library size, plasmid instability, and heterozygosity. Here, a large library of random mutant was created by inserting error-prone PCR (epPCR) products to the chromosome of B. subtilis. Specifically, the epPCR product was fused with flanking regions and antibiotic resistant marker using a PCR-based multimerization method, generating insertion construct. The epPCR product was integrated into the chromosome via homologous recombination after the insertion construct was transformed into the supercompetent cells of B. subtilis strain SCK6. The transformation efficiency of the insertion construct was improved through co-expressing homologous recombination-promoting protein NgAgo, raising the number of competent cells, and increasing the length of flanking regions. A library containing 5.31 × 105 random mutants was constructed using per µg insertion construct, which is sufficient for directed evolution. The library generation process was accomplished within 1 day. The effectiveness of this method was confirmed by improving the activity of Methyl Parathion Hydrolase (MPH) toward chlorpyrifos and by enhancing the secretion level of MPH in B. subtilis. Taken together, the present work provides a fast and efficient method to integrate epPCR products into the chromosome of B. subtilis, facilitating directed evolution and expression optimization of target proteins.

A Physically Triggered Cell Death via Transbarrier Cold Atmospheric Plasma Cancer Treatment.

Cold atmospheric plasma (CAP) is a near room-temperature ionized gas composed of highly reactive species. CAP also generates thermal radiation, ultraviolet radiation, and electromagnetic (EM) waves. So far, nearly all biological effects of CAP have relied on the chemical factors in CAP. Here, we first show that the EM emission from CAP can lead to the death of melanoma cells via a transbarrier contactless method. Compared with reactive species, the effect of the physical factors causes much stronger growth inhibition on a reactive species-resistant melanoma cell line B16F10. Such a physically triggered growth inhibition is due to a new cell death type, characterized by the rapid leakage of bulk solutions from the cells, resulting in cytoplasm shrinkage and bubbling on the cell membrane. The physically based CAP-triggered cell death can occur even there is a macroscale gap between the bulk CAP and cells, which includes an air gap (∼8 mm) and a dielectric material of the dish or plate (∼1 mm). Either a too large or a too small gap will inhibit such cell death. The physically triggered cellular pressure may cause the bubbling on cells, which can be inhibited in a hypotonic environment via the extracellular osmotic pressure. This study builds a foundation to use CAP as a physically based noninvasive cancer treatment.

The Cell Activation Phenomena in the Cold Atmospheric Plasma Cancer Treatment.

Cold Atmospheric Plasma (CAP) is an ionized gas with a near room temperature. CAP is a controllable source for reactive species, neutral particles, electromagnetic field and UV radiation. CAP showed the promising application in cancer treatment through the demonstration in vitro and in vivo. In this study, we first demonstrate the existence of an activation state on the CAP-treated cancer cells, which drastically decreases the threshold of cell vulnerability to the cytotoxicity of the CAP-originated reactive species such as H2O2 and NO2-. The cytotoxicity of CAP treatment is still dependent on the CAP-originated reactive species. The activation state of cancer cells will not cause noticeable cytotoxicity. This activation is an instantaneous process, started even just 2 s after the CAP treatment begins. The noticeable activation on the cancer cells starts 10-20 s during the CAP treatment. In contrast, the de-sensitization of activation takes 5 hours after the CAP treatment. The CAP-based cell activation explains the mechanism by which direct CAP treatment causes a much stronger cytotoxicity over the cancer cells compared with an indirect CAP treatment do, which is a key to understand what the effect of CAP on cancer cells.

Photolithographic-stereolithographic-tandem fabrication of 4D smart scaffolds for improved stem cell cardiomyogenic differentiation.

4D printing is a highly innovative additive manufacturing process for fabricating smart structures with the ability to transform over time. Significantly different from regular 4D printing techniques, this study focuses on creating novel 4D hierarchical micropatterns using a unique photolithographic-stereolithographic-tandem strategy (PSTS) with smart soybean oil epoxidized acrylate (SOEA) inks for effectively regulating human bone marrow mesenchymal stem cell (hMSC) cardiomyogenic behaviors. The 4D effect refers to autonomous conversion of the surficial-patterned scaffold into a predesigned construct through an external stimulus delivered immediately after printing. Our results show that hMSCs actively grew and were highly aligned along the micropatterns, forming an uninterrupted cellular sheet. The generation of complex patterns was evident by triangular and circular outlines appearing in the scaffolds. This simple, yet efficient, technique was validated by rapid printing of scaffolds with well-defined and consistent micro-surface features. A 4D dynamic shape change transforming a 2-D design into flower-like structures was observed. The printed scaffolds possessed a shape memory effect beyond the 4D features. The advanced 4D dynamic feature may provide seamless integration with damaged tissues or organs, and a proof of concept 4D patch for cardiac regeneration was demonstrated for the first time. The 4D-fabricated cardiac patch showed significant cardiomyogenesis confirmed by immunofluorescence staining and qRT-PCR analysis, indicating its promising potential in future tissue and organ regeneration applications.

[Delayed gastric emptying in 5 case].

It is a common way for estimating of time of death in forensic science by the extent of gastric emptying, but this method may be less accurate in sometimes. Here, we report 5 cases with significant delayed gastric emptying and made discussion about it.