Element dependence of enhancement in optics emission from laser-induced plasma under spatial confinement

In this study, the element dependence of spatial confinement effects in LIBS has been studied. Hemispheric cavities were used to confine laser-induced plasmas from aluminum samples with other trace elements. The enhancement factors were found to be dependent on the elements. Equations describing the element dependent enhancement factors were successfully deduced from the local thermodynamic equilibrium conditions, which have also been verified by the experimental results. Research results show that enhancement factors in LIBS with spatial confinement depend on the temperature, electron density, and compression ratio of plasmas, and vary with elements and atomic/ionic emission lines selected. Generally, emission lines with higher upper level energies have higher enhancement factors. Furthermore, with enhancement factor of a spectral line, temperatures and electron densities of plasmas known, enhancement factors of all the other elements in the plasmas could be estimated by the equations developed in this study

Preparation and Characterization of Potato Starch Film with Various Size of Nano-SiO2

The various sizes (15, 30, 80, and 100 nm) of nano-SiO2/potato starch films were synthesized and characterized. The gas permeability, antibacterial properties, and mechanical properties of the films were evaluated to their potential for application as food packaging materials. Results indicated that the 100 nm nano-SiO2 was well dispersed in the starch matrix, which induced an active group on the surface of 100 nm nano-SiO2 adequately combined with starch macromolecule. The water resistance and mechanical properties of the films were improved with the addition of nano-SiO2. Notably, resistance to ultraviolet and thermal aging was also enhanced. The nano-SiO2/potato starch films were more efficient against Escherichia coli (E. coli) than Staphylococcus aureus (S. aureus). Remarkable preservation properties of the films packaging the white mushrooms were obtained, with those of the 100 nm films considered superior. This study can significantly guide the rational choice of the nano-SiO2 size to meet the packaging requirements of various agricultural products

Synthesis and Characterization of <i>Konjac Glucomannan</i>/<i>Carrageenan</i>/Nano-silica Films for the Preservation of Postharvest White Mushrooms

In this study, the konjac glucomannan (KGM)/carrageenan (KC)/nano-silica film was prepared and characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The preservation quality of white mushrooms (Agaricus bisporus) packed using the films was also determined. The nano-silica dosage was found to affect the properties of the nanocomposite KGM/KC films. The results indicated that the properties of the films were significantly improved with the addition of nano-silica. The water vapor permeability, water solubility, moisture absorption, and light transmittance of KGM/KC/nano-silica films were significantly affected by the nano-silica dosage. In this study, the optimal nano-silica dosage to incorporate into the film in order to achieve excellent performance was 0.3%. Strong intermolecular hydrogen bonds were also observed between KGM/KC and nano-silica in the KGM/KC/nano-silica film by FTIR. In addition, the KGM/KC/nano-silica film markedly reduced the browning index, delayed the weight loss and softening, and extended the shelf life of mushrooms during storage at 4 &#176;C. The KGM/KC film modified using nano-silica can provide a potential method for improving the preservation quality of white mushrooms during storage

Pressure‐Temperature Dual‐Parameter Flexible Sensors Based on Conformal Printing of Conducting Polymer PEDOT:PSS on Microstructured Substrate

Abstract Flexible sensors play an important role in collecting stimuli information and sending them to a central processing unit or cloud for analysis and decision‐making. As much information is needed to be collected, the fabrication of multiparameter flexible sensors is becoming increasingly urgent. To this end, conducting polymer‐based composites have been proven as promising materials for developing pressure‐temperature dual‐parameter sensors. However, fabrication of ideal dual‐parameter sensors with fully decoupled pressure‐temperature readings, good sensitivity, and a simple preparation process remain challenges. Here, a strategy of fabricating a pressure‐temperature dual‐parameter sensor based on conformal printing of conducting polymer poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) on the surface of microstructured polydimethylsiloxane (PDMS) substrate is demonstrated. It is found that secondary doped PEDOT:PSS provides temperature‐independent conductivity. Combined with the sea‐island microstructured PDMS substrate, a screen‐printed flexible sensor demonstrates fully decoupled pressure‐temperature reading ability, competitive sensitivity, and good stability. The excellent sensing properties of the devices, with a maximum pressure sensitivity of 134.25 kPa−1 and linear response region over 300 kPa as well as highly sensitive temperature sensing for finger touch, together with their unique advantages of low‐cost and large‐area fabrication, make the printed flexible dual‐parameter sensors promising applications in electric‐skin (e‐skin), human‐machine interaction, and robotics

Characterization and Release Kinetics Study of Active Packaging Films Based on Modified Starch and Red Cabbage Anthocyanin Extract

Active packaging films were prepared by adding red cabbage anthocyanin extract (RCAE) into acetylated distarch phosphate (ADSP). This paper investigated the influence of the interaction relationship between RCAE and the film matrix on the structure, barrier, antioxidant and release properties of active films. Sixteen principal compounds in RCAE were identified as anthocyanins based on mass spectroscopic analysis. Micromorphological observations indicated that the RCAE distribution uniformity in the films decreased as the RCAE content increased. When the concentration of RCAE was not higher than 20%, the moisture absorption and oxygen permeability of films decreased. The stability of RCAE in the films was enhanced by the electrostatic interaction between RCAE and ADSP with the formation of hydrogen bonds, which facilitated the sustainability of the antioxidant properties of films. The release kinetics of RCAE proved that the release rate of RCAE in active films was the fastest in distilled water, and Fickian&rsquo;s law was appropriate for portraying the release behavior. Moreover, the cytocompatibilty assay showed that the test films were biocompatible with a viability of &gt;95% on HepG2 cells. Thus, this study has established the suitability of the films for applications in active and food packaging

CRISPR-Cas12a-integrated transgenes in genomic safe harbors retain high expression in human hematopoietic iPSC-derived lineages and primary cells

Discovery of genomic safe harbor sites (SHSs) is fundamental for multiple transgene integrations, such as reporter genes, chimeric antigen receptors (CARs), and safety switches, which are required for safe cell products for regenerative cell therapies and immunotherapies. Here we identified and characterized potential SHS in human cells. Using the CRISPR-MAD7 system, we integrated transgenes at these sites in induced pluripotent stem cells (iPSCs), primary T and natural killer (NK) cells, and Jurkat cell line, and demonstrated efficient and stable expression at these loci. Subsequently, we validated the differentiation potential of engineered iPSC toward CD34+ hematopoietic stem and progenitor cells (HSPCs), lymphoid progenitor cells (LPCs), and NK cells and showed that transgene expression was perpetuated in these lineages. Finally, we demonstrated that engineered iPSC-derived NK cells retained expression of a non-virally integrated anti-CD19 CAR, suggesting that several of the investigated SHSs can be used to engineer cells for adoptive immunotherapies