Self-Assembled Skin-Penetrating Peptides with Controlled Supramolecular Properties for Enhanced Transdermal Delivery.

The use of nanocarriers decorated with penetration-enhancing agents (PEAs) is considered to be a promising approach for efficient transdermal delivery. In this study, we developed short amphiphilic skin-penetrating peptides (17 amino acids) that functioned not only as PEAs but also as building blocks of nanocarriers without the incorporation of additional macromolecules for self-assembly and guest molecule encapsulation. Interestingly, varying only two amino acids in the hydrophobic moiety of the peptides resulted in significantly different self-assembly behavior, thermal stability, protease resistance, and skin-penetration efficiency in a human skin model. The analysis of the peptide secondary structure revealed that such characteristic changes arose due to the sequence variation-mediated conformational change in the hydrophobic block. These findings hold significant promise for the development of simple and effective delivery systems exhibiting controllable supramolecular properties.

Lightweight Transformer Model for Mobile Application Classification.

Recently, realistic services like virtual reality and augmented reality have gained popularity. These realistic services require deterministic transmission with end-to-end low latency and high reliability for practical applications. However, for these real-time services to be deterministic, the network core should provide the requisite level of network. To deliver differentiated services to each real-time service, network service providers can classify applications based on traffic. However, due to the presence of personal information in headers, application classification based on encrypted application data is necessary. Initially, we collected application traffic from four well-known applications and preprocessed this data to extract encrypted application data and convert it into model input. We proposed a lightweight transformer model consisting of an encoder, a global average pooling layer, and a dense layer to categorize applications based on the encrypted payload in a packet. To enhance the performance of the proposed model, we determined hyperparameters using several performance evaluations. We evaluated performance with 1D-CNN and ET-BERT. The proposed transformer model demonstrated good performance in the performance evaluation, with a classification accuracy and F1 score of 96% and 95%, respectively. The time complexity of the proposed transformer model was higher than that of 1D-CNN but performed better in application classification. The proposed transformer model had lower time complexity and higher classification performance than ET-BERT.

Characteristics of Staphylococcus aureus biofilm matured in tryptic soy broth, low-fat milk, or whole milk samples along with inactivation by 405 nm light combined with folic acid.

In the present study, the characteristics of Staphylococcus aureus biofilms matured in tryptic soy broth (TSB), low-fat milk, or whole milk samples were identified along with their resistance to 405 nm light with or without folic acid. Phenotypic properties of carbohydrate and protein contents in extracellular polymeric substance (EPS) of S. aureus biofilms matured in different conditions were identified. The carbohydrate content was higher in the biofilm matured in low-fat milk (1.27) than the samples matured in whole milk (0.58) and TSB (0.10). Protein content in the EPS of biofilm was higher in the sample matured in whole milk (6.59) than the samples matured in low-fat milk (3.24) and TSB (2.08). Moreover, the maturation condition had a significant effect on the membrane lipid composition of the biofilm, producing more unsaturated fatty acids in biofilm matured in milk samples. These changes in biofilm matured in milk samples increased the resistance of S. aureus to 405 nm light in the presence of folic acid (LFA). Additionally, transcriptomic analysis was conducted to identify the response of S. aureus biofilm to LFA treatment. Several genes related to DNA and protein protection from oxidative stress along with biofilm accumulation were overexpressed in the LFA-treated biofilms. These results indicate the maturation of S. aureus biofilm in various samples and the biofilms responses to bactericidal treatments.

TiO2-based photocatalyst Generated Reactive Oxygen Species cause cell membrane disruption of Staphylococcus aureus and Escherichia coli O157:H7.

Photocatalysts, including titanium dioxide (TiO2), have attracted much attention in food safety for controlling foodborne pathogens. However, the study of the photocatalytic activity on various food-surrounding media and the factors that affect the efficacy of photocatalytic inactivation is incomplete. In this study, to inactivate foodborne pathogens in food-surrounding environments, TiO2-based photocatalysts with ultraviolet A (UVA, 365 nm) and visible light (VIS, 405 nm) were employed. Three TiO2-based photocatalysts, namely, Degussa P25 TiO2, carbon-modified KRONOClean 7000® (C-TiO2), and Pt-doped Ishihara-Sangyo MPT-623 (Pt-TiO2) inactivated Staphylococcus aureus and Escherichia coli O157:H7 exposed to UVA and VIS light in both water and air samples. Among them, Degussa P25 under UVA showed the highest bactericidal effects in both water and air treatments, which induced 5.19 log reductions in S. aureus when treated for 11.68 J/cm2, and E. coli O157:H7 was reduced by more than 6.21 log for 1.32 J/cm2 in the water sample. For air treatment, the combination of Degussa P25 and UVA achieved 3.45 and 3.28 log reductions for Staphylococcus aureus and E. coli O157:H7, respectively, in a developed laboratory-scale chamber for 1 h and 20.02 J/cm2. Scavenger assays showed that regardless of the photocatalyst and wavelength used, reactive oxygen species (ROS) generation causes cell membrane disruption of foodborne pathogens. However, the types of ROS that are generated vary among the photocatalysts and are related to different bactericidal efficacies. These results indicated that TiO2-based photocatalytic activity can be used to control microbiological hazards in various environments in the food industry.

Effects of storage temperature on microbiota shifts in raw milk biofilm developed on stainless steel.

This study aimed to investigate the microbiota in raw milk and the influence of storage temperature on the microbiota shift after biofilm formation. Raw milk stored at 4 °C and biofilms developed in raw milk incubated at 4 °C or 25 °C for 7 days were subjected to microbiota analysis as well as quantitative analyses of aerobic or anaerobic bacteria. The levels of aerobic bacteria increased during biofilm formation, while no significant changes were observed within anaerobic bacteria. In addition, there was a difference between aerobic and anaerobic bacterial counts in raw milk and biofilm stored for 7 days. The pattern of microbial composition differed by temperature. In addition, the genus Pseudomonas (53-71%) occupied a high proportion in raw milk, and the raw milk biofilm developed at 4 °C, while the genus Lactobacillus (75-83%) was predominant in biofilms developed at 25 °C. Intriguingly, bacterial richness was higher in raw milk on day 0 and biofilm developed at 4 °C than raw milk after 7 days of storage at 4 °C. These findings suggest that temperature critically affects the bacterial composition of both raw milk and its associated biofilm.

Bacterial composition of refrigerators in households and inactivation of airborne Staphylococcus aureus using a TiO2-UVLED module in a 512 L aerobiology chamber.

This study aimed to investigate the microbiota in the air and on the surface of a refrigerator and to inactivate aerosolized Staphylococcus aureus using a TiO2-UVLED module. A total of 100 L of the air and 5000 cm2 surfaces in seven household refrigerators were collected using an air sampler and a swab, respectively. Samples were subjected to microbiota analysis as well as quantitative analyses of aerobic or anaerobic bacteria. The level of airborne aerobic bacteria was 4.26 log CFU/vol (100 L), while that of surface aerobic bacteria was 5.27 log CFU/surface (5000 cm2). PCoA based on the Bray-Curtis metric revealed that the bacterial composition differed between samples collected from refrigerators with and without a vegetable drawer. Moreover, pathogenic bacteria containing genera and order from each sample were found, such as Enterobacaterales, Pseudomonas, Staphylococcus, Listeria, and Bacillus. Among them, Staphylococcus aureus was determined to be a core hazardous pathogen in air. Therefore, three S. aureus strains isolated from the air in refrigerators, as well as a reference strain of S. aureus (ATCC 6538P), were inactivated by a TiO2-UVLED module in a 512 L aerobiology chamber. All aerosolized S. aureus were reduced over 1.6 log CFU/vol after treatment with TiO2 under UVA (365 nm) light at 40 J/cm2. These findings suggest that TiO2-UVLED modules have the potential to be used to control airborne bacteria in household refrigerators.

FragTracer: Real-Time Fragmentation Monitoring Tool for F2FS File System.

Emerging hardware devices (e.g., NVMe SSD, RISC-V, etc.) open new opportunities for improving the overall performance of computer systems. In addition, the applications try to fully utilize hardware resources to keep up with those improvements. However, these trends can cause significant file system overheads (i.e., fragmentation issues). In this paper, we first study the reason for the fragmentation issues on an F2FS file system and present a new tool, called FragTracer, which helps to analyze the ratio of fragmentation in real-time. For user-friendly usage, we designed FragTracer with three main modules, monitoring, pre-processing, and visualization, which automatically runs without any user intervention. We also optimized FragTracer in terms of performance to hide its overhead in tracking and analyzing fragmentation issues on-the-fly. We evaluated FragTracer with three real-world databases on the F2FS file system, so as to study the fragmentation characteristics caused by databases, and we compared the overhead of FragTracer. Our evaluation results clearly show that the overhead of FragTracer is negligible when running on commodity computing environments.

The Role of CPNE7 (Copine-7) in Colorectal Cancer Prognosis and Metastasis.

Colorectal cancer (CRC) is one of the most common and deadly cancers in the world. However, no effective treatment for the disease has yet been found. For this reason, several studies are being carried out on the treatment of CRC. Currently, there is limited understanding of the role of CPNE7 (copine-7) in CRC progression and metastasis. The results of this study show that CPNE7 exerts an oncogenic effect in CRC. First, CPNE7 was shown to be significantly up-regulated in CRC patient tissues and CRC cell lines compared to normal tissues according to IHC staining, qRT-PCR, and western blotting. Next, this study used both systems of siRNA and shRNA to suppress CPNE7 gene expression to check the CPNE7 mechanism in CRC. The suppressed CPNE7 significantly inhibited the growth of CRC cells in in vitro experiments, including migration, invasion, and semisolid agar colony-forming assay. Moreover, the modified expression of CPNE7 led to a decrease in the levels of genes associated with epithelial-mesenchymal transition (EMT). The epithelial genes E-cadherin (CDH1) and Collagen A1 were upregulated, and the levels of mesenchymal genes such as N-cadherin (CDH2), ZEB1, ZEB2, and SNAIL (SNAL1) were downregulated after CPNE7 inhibition. This study suggests that CPNE7 may serve as a potential diagnostic biomarker for CRC patients.

SEPHS1: Its evolution, function and roles in development and diseases.

Selenophosphate synthetase (SEPHS) was originally discovered in prokaryotes as an enzyme that catalyzes selenophosphate synthesis using inorganic selenium and ATP as substrates. However, in contrast to prokaryotes, two paralogs, SEPHS1 and SEPHS2, occur in many eukaryotes. Prokaryotic SEPHS, also known as SelD, contains either cysteine (Cys) or selenocysteine (Sec) in the catalytic domain. In eukaryotes, only SEPHS2 carries out selenophosphate synthesis and contains Sec at the active site. However, SEPHS1 contains amino acids other than Sec or Cys at the catalytic position. Phylogenetic analysis of SEPHSs reveals that the ancestral SEPHS contains both selenophosphate synthesis and another unknown activity, and that SEPHS1 lost the selenophosphate synthesis activity. The three-dimensional structure of SEPHS1 suggests that its homodimer is unable to form selenophosphate, but retains ATPase activity to produce ADP and inorganic phosphate. The most prominent function of SEPHS1 is that it is implicated in the regulation of cellular redox homeostasis. Deficiency of SEPHS1 leads to the disturbance in the expression of genes involved in redox homeostasis. Different types of reactive oxygen species (ROS) are accumulated in response to SEPHS deficiency depending on cell or tissue types. The accumulation of ROS causes pleiotropic effects such as growth retardation, apoptosis, DNA damage, and embryonic lethality. SEPHS1 deficiency in mouse embryos affects retinoic signaling and other related signaling pathways depending on the embryonal stage until the embryo dies at E11.5. Dysregulated SEPHS1 is associated with the pathogenesis of various diseases including cancer, Crohn's disease, and osteoarthritis.

Inactivation of Escherichia coli O157:H7 and Salmonella Typhimurium in black and red pepper by vacuumed hydrogen peroxide vapour.

AIMS: In this study, the efficacy of using vacuumed hydrogen peroxide vapour (VHPV) to inactivate foodborne pathogens in whole dried black pepper (Piper nigrum) and powdered dried red pepper (Capsicum annuum) was evaluated. METHODS AND RESULTS: Black and red pepper inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium were subjected to 3.81, 7.93, 12.33, 17.04 and 21.67 mg l-1 VHPV for 1 min, and the change in pepper colour was evaluated after treatment. Pathogen quantities decreased with increasing hydrogen peroxide concentration. For black pepper, the 21.67 mg l-1 VHPV treatment decreased E. coli O157:H7 and S. Typhimurium quantities by >6.12 and 4.52 log CFU per gram, respectively, without causing colour change. In addition, the 21.67 mg l-1 VHPV treatment caused 4.35 and 2.36 log CFU per gram reductions in these two pathogen quantities in red pepper, respectively. During the VHPV treatment, colour values of peppers did not significantly change. CONCLUSIONS: VHPV effectively reduced the levels of foodborne pathogens in black and red pepper while inducing minimal colour changes. SIGNIFICANCE AND IMPACT OF THE STUDY: Hydrogen peroxide vapour (HPV) is typically used as a sterilization method for medical devices, and many studies have confirmed the effectiveness of HPV or the gaseous phase of hydrogen peroxide on the inactivation of micro-organisms. However, using HPV for food pasteurization has rarely been studied. In the present study, we confirmed that VHPV effectively reduced the levels of pathogens in black and red pepper without colour changes.

L. monocytogens exhibited less cell membrane damage, lipid peroxidation, and intracellular reactive oxygen species accumulation after plasma-activated water treatment compared to E. coli O157:H7 and S. Typhimurium.

This study investigated the bactericidal activity of plasma-activated water (PAW) generated with a remote discharge reactor against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes. PAW-40, -80, and -120, prepared by activating distilled water for 40, 80, and 120 min, respectively, showed inactivation activity against pathogenic bacteria, which increased as the activation time increased due to decrease in pH and increase in oxidation-reduction potential and reactive oxygen/nitrogen species (RONS) of PAW. In addition, Gram-positive bacteria L. monocytogenes showed superior resistance to PAW than Gram-negative bacteria E. coli O157:H7 and S. Typhimurium. Compared with E. coli O157:H7 and S. Typhimurium, L. monocytogens exhibited less cell membrane damage, lipid peroxidation, and intracellular ROS accumulation after PAW treatment, which indicated that L. monocytogenes exhibited greater resistance because the thick cell wall buffered RONS diffusion into the cell. PAW also showed a control effect on the pathogenic bacteria on cherry tomato, and the effect was maintained throughout five repeated applications; thus, proposing high reusability of PAW. The results of this study propose that PAW generated with a remote discharge reactor can be utilized for pathogen control and provides basic data for related research and practical industrial applications.

Antibacterial Activity of Caffeic Acid Combined with UV-A Light against Escherichia coli O157:H7, Salmonella enterica Serovar Typhimurium, and Listeria monocytogenes.

The aim of this study was to evaluate the antibacterial activity of caffeic acid (CA), which is a natural polyphenol, combined with UV-A light against the representative foodborne bacteria Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes. Data regarding the inactivation of these bacteria and its dependence on CA concentration, light wavelength, and light dose were obtained. E. coli O157:H7 and Salmonella Typhimurium were reduced to the detection limit when treated with 3 mM CA and UV-A for 3 J/cm2 and 4 J/cm2, respectively, and 5 J/cm2 treatment induced 3.10 log reduction in L. monocytogenes. To investigate the mechanism for inactivation of Salmonella Typhimurium and L. monocytogenes, measurement of polyphenol uptake, membrane damage assessment, enzymatic activity assay, and transmission electron microscopy (TEM) were conducted. It was revealed that CA was significantly (P < 0.05) absorbed by bacterial cells, and UV-A light allowed a higher uptake of CA for both pathogens. Additionally, CA plus UV-A treatment induced significant (P < 0.05) cell membrane damage. In the enzymatic activity assay, the activities of both pathogens were reduced by CA, and a greater reduction occurred by use of CA plus UV-A. Moreover, transmission electron microscopy (TEM) images indicated that CA plus UV-A treatment notably destroyed the intercellular structure. In addition, antibacterial activity was also observed in commercial apple juice, which showed results similar to those obtained from phosphate-buffered saline (PBS), resulting in a significant (P < 0.05) reduction for all three pathogens without any changes in color parameters (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity. IMPORTANCE Photodynamic inactivation (PDI), which involves photoactivation of a photosensitizer (PS), is an emerging field of study, as it effectively reduces various kinds of microorganisms. Although there are several PSs that have been used for PDI, there is a need to find naturally occurring PSs for safer application in the food industry. Caffeic acid, a natural polyphenol found in most fruits and vegetables, has recently been studied for its potential to act as a novel photosensitizer. However, no studies have been conducted regarding its antibacterial activity depending on treatment conditions and its antibacterial mechanism. In this study, we closely examined the effectiveness of caffeic acid in combination with UV-A light for inactivating representative foodborne bacteria in liquid medium. Therefore, the results of this research are expected to be utilized as basic data for future application of caffeic acid in PDI, especially when controlling pathogens in liquid food processing.

Prognostic impact of GPR56 in patients with colorectal cancer.

G protein-coupled receptor 56 (GPR56) belongs to the adhesion G protein-coupled receptor subfamily, which plays a role in cell progression and survival. The aim of this study was to investigate the role of the GPR56 gene in a cell line study and the impact of its protein expression on the prognosis of colorectal cancer (CRC) patients. The effect of GPR56 on tumor cell proliferation (WST-1 assay), invasion (Transwell assay), migration (Transwell assay, wound healing assay), and colony-forming ability (semisolid agar colony-forming assay) was explored. The expression levels of GPR56 in tissue samples of 109 CRC patients were evaluated by immunohistochemistry. The prognostic value of GRP56 was analyzed using univariate and multivariate analyses. The downregulation of GPR56 in the CRC cell line reduced cell proliferation as compared with that in a control sample (48 h; p=0.042, 72 h; p=0.001). Downregulation of the GPR56 expression reduced cell invasion and migration abilities and inhibited colony-forming abilities (p<0.005). The 5-year overall survival rate was worse in the high-expression group as compared with that in the low-expression group (51.6% vs. 74.4%, p=0.008). High GPR56 expression was a significant prognostic factor for overall survival of CRC patients in the univariate (p=0.001) and multivariate (p<0.001) analyses. The expression level of GPR56 plays an important role in tumor progression in CRC, and it may serve as a prognostic indicator in CRC patients.

Synergistic bactericidal effect of hot water with citric acid against Escherichia coli O157:H7 biofilm formed on stainless steel.

This study investigated the antimicrobial effect of hot water with citric acid against Escherichia coli O157:H7 biofilm on stainless steel (SS). Hot water (50, 60, or 70 °C) with 2% citric acid exhibited a synergistic bactericidal effect on the pathogen biofilm. It was revealed that hot water and citric acid combination induced sub-lethally injured cells. Additionally, mechanisms of the synergistic bactericidal effects of hot water with citric acid were identified through several approaches. In terms of biofilm matrix, hot water removes exopolysaccharides, a major component of extracellular polymeric substances (EPS), thereby increasing contact between surface cells and citric acid, resulting in a synergistic bactericidal effect. In terms of the cell itself, increased permeability of citric acid through cell membranes destructed by hot water promotes the inactivation of superoxide dismutase (SOD) in E. coli O157:H7, which induce synergistic generation of reactive oxygen species (ROS) which promote inactivation of cell by activating lipid peroxidation, resulting in destruction of the cell membrane. Therefore, it is interpreted that when hot water with citric acid is applied to E. coli O157:H7 biofilm, synergy effects on the biofilm matrix and cell itself have a complex interaction with each other, thus causing a dramatic synergistic bactericidal effect.

Constitutive Oxidative Stress by SEPHS1 Deficiency Induces Endothelial Cell Dysfunction.

The primary function of selenophosphate synthetase (SEPHS) is to catalyze the synthesis of selenophosphate that serves as a selenium donor during selenocysteine synthesis. In eukaryotes, there are two isoforms of SEPHS (SEPHS1 and SEPHS2). Between these two isoforms, only SEPHS2 is known to contain selenophosphate synthesis activity. To examine the function of SEPHS1 in endothelial cells, we introduced targeted null mutations to the gene for SEPHS1, Sephs1, in cultured mouse 2H11 endothelial cells. SEPHS1 deficiency in 2H11 cells resulted in the accumulation of superoxide and lipid peroxide, and reduction in nitric oxide. Superoxide accumulation in Sephs1-knockout 2H11 cells is due to the induction of xanthine oxidase and NADPH oxidase activity, and due to the decrease in superoxide dismutase 1 (SOD1) and 3 (SOD3). Superoxide accumulation in 2H11 cells also led to the inhibition of cell proliferation and angiogenic tube formation. Sephs1-knockout cells were arrested at G2/M phase and showed increased gamma H2AX foci. Angiogenic dysfunction in Sephs1-knockout cells is mediated by a reduction in nitric oxide and an increase in ROS. This study shows for the first time that superoxide was accumulated by SEPHS1 deficiency, leading to cell dysfunction through DNA damage and inhibition of cell proliferation.

Application of a Krypton-Chlorine Excilamp To Control Alicyclobacillus acidoterrestris Spores in Apple Juice and Identification of Its Sporicidal Mechanism.

The aim of this study was to investigate the sporicidal effect of a krypton-chlorine (KrCl) excilamp against Alicyclobacillus acidoterrestris spores and to compare its inactivation mechanism to that of a conventional UV lamp containing mercury (Hg). The inactivation effect of the KrCl excilamp was not significantly different from that of the Hg UV lamp for A. acidoterrestris spores in apple juice despite the 222-nm wavelength of the KrCl excilamp having a higher absorption coefficient in apple juice than the 254-nm wavelength of the Hg UV lamp; this is because KrCl excilamps have a fundamentally greater inactivation effect than Hg UV lamps, which is confirmed under ideal conditions (phosphate-buffered saline). The inactivation mechanism analysis revealed that the DNA damage induced by the KrCl excilamp was not significantly different (P > 0.05) from that induced by the Hg UV lamp, while the KrCl excilamp caused significantly higher (P < 0.05) lipid peroxidation incidence and permeability change in the inner membrane of A. acidoterrestris spores than did the Hg UV lamp. Meanwhile, the KrCl excilamp did not generate significant (P > 0.05) intracellular reactive oxygen species, indicating that the KrCl excilamp causes damage only through the direct absorption of UV light. In addition, after KrCl excilamp treatment with a dose of 2,011 mJ/cm2 to reduce A. acidoterrestris spores in apple juice by 5 logs, there were no significant (P > 0.05) changes in quality parameters such as color (L*, a*, and b*), total phenolic compounds, and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity.IMPORTANCEAlicyclobacillus acidoterrestris spores, which have high resistance to thermal treatment and can germinate even at low pH, are very troublesome in the juice industry. UV technology, a nonthermal treatment, can be an excellent means to control heat-resistant A. acidoterrestris spores in place of thermal treatment. However, the traditionally applied UV sources are lamps that contain mercury (Hg), which is harmful to humans and the environment; thus, there is a need to apply novel UV technology without the use of Hg. In response to this issue, excilamps, an Hg-free UV source, have been actively studied. However, no studies have been conducted applying this technique to control A. acidoterrestris spores. Therefore, the results of this study, which applied a KrCl excilamp for the control of A. acidoterrestris spores and elucidated the inactivation principle, are expected to be utilized as important basic data for application to actual industry or conducting further studies.

Inactivation Kinetics and Membrane Potential of Pathogens in Soybean Curd Subjected to Pulsed Ohmic Heating Depending on Applied Voltage and Duty Ratio.

The aim of this research was to investigate the efficacy of the duty ratio and applied voltage in the inactivation of pathogens in soybean curd by pulsed ohmic heating (POH). The heating rate of soybean curd increased rapidly as the applied voltage increased, although the duty ratio did not affect the temperature profile. We supported this result by verifying that electrical conductivity increased with the applied voltage. Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in soybean curd were significantly (P < 0.05) inactivated by more than 1 log unit at 80 Vrms (root mean square voltage). To elucidate the mechanism underlying these results, the membrane potential of the pathogens was examined using DiBAC4(3) [bis-(1,3-dibutylbarbituric acid)trimethine oxonol] on the basis of a previous study showing that the electric field generated by ohmic heating affected the membrane potential of cells. The values of DiBAC4(3) accumulation increased under increasing applied voltage, and they were significantly (P < 0.05) higher at 80 Vrms, while the duty ratio had no effect. In addition, morphological analysis via transmission electron microscopy showed that electroporation and expulsion of intracellular materials were predominant at 80 Vrms Moreover, electrode corrosion was overcome by the POH technique, and the textural and color properties of soybean curd were preserved. These results substantiate the idea that the applied voltage has a profound effect on the microbial inactivation of POH as a consequence of not only the thermal effect, but also the nonthermal effect, of the electric field, whereas the duty ratio does not have such an effect.IMPORTANCE High-water-activity food products, such as soybean curd, are vulnerable to microbial contamination, which causes fatal foodborne diseases and food spoilage. Inactivating microorganisms inside food is difficult because the transfer of thermal energy is slower inside than it is outside the food. POH is an adequate sterilization technique because of its rapid and uniform heating without causing electrode corrosion. To elucidate the electrical factors associated with POH performance in the inactivation of pathogens, the effects of the applied voltage and duty ratio on POH were investigated. In this study, we verified that a high applied voltage (80 Vrms) at a duty ratio of 0.1 caused thermal and nonthermal effects on pathogens that led to an approximately 4-log-unit reduction in a significantly short time. Therefore, the results of this research corroborate database predictions of the inactivation efficiency of POH based on pathogen control strategy modeling.

Versatile Low-Cost Volumetric 3D Ultrasound Imaging Using Gimbal-Assisted Distance Sensors and an Inertial Measurement Unit.

This study aims at creating low-cost, three-dimensional (3D), freehand ultrasound image reconstructions from commercial two-dimensional (2D) probes. The low-cost system that can be attached to a commercial 2D ultrasound probe consists of commercial ultrasonic distance sensors, a gimbal, and an inertial measurement unit (IMU). To calibrate irregular movements of the probe during scanning, relative position data were collected from the ultrasonic sensors that were attached to a gimbal. The directional information was provided from the IMU. All the data and 2D ultrasound images were combined using a personal computer to reconstruct 3D ultrasound image. The relative position error of the proposed system was less than 0.5%. The overall shape of the cystic mass in the breast phantom was similar to those from 2D and sections of 3D ultrasound images. Additionally, the pressure and deformations of lesions could be obtained and compensated by contacting the probe to the surface of the soft tissue using the acquired position data. The proposed method did not require any initial marks or receivers for the reconstruction of a 3D ultrasound image using a 2D ultrasound probe. Even though our system is less than $500, a valuable volumetric ultrasound image could be provided to the users.

Decontamination Effect of the Spindle and 222-Nanometer Krypton-Chlorine Excimer Lamp Combination against Pathogens on Apples (Malus domestica Borkh.) and Bell Peppers (Capsicum annuum L.).

In this study, we developed a washing system capable of decontaminating fresh produce by combining the Spindle apparatus, which detaches microorganisms on sample surfaces, and a 222-nm krypton-chlorine excimer lamp (KrCl excilamp) (Sp-Ex) and investigated their decontamination effect against Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes on apple (Malus domestica Borkh.) and bell pepper (Capsicum annuum L.) surfaces. Initial levels of the three pathogens were approximately 108 CFU/sample. Both E. coli O157:H7 and S. Typhimurium were reduced to below the detection limit (2.0 log CFU/sample) after 5 and 7 min of treatment on apple and bell pepper surfaces, respectively. The amounts of L. monocytogenes on apple and bell pepper surfaces were reduced by 4.26 and 5.48 logs, respectively, after 7 min of treatment. The decontamination effect of the Sp-Ex was influenced by the hydrophobicity of the sample surface as well as the microbial cell surface, and the decontamination effect decreased as the two hydrophobicity values increased. To improve the decontamination effect of the Sp-Ex, Tween 20, a surfactant that weakens the hydrophobic interaction between the sample surface and pathogenic bacteria, was incorporated into Sp-Ex processing. It was found that its decontamination effect was significantly (P < 0.05) increased by the addition of 0.1% Tween 20. Sp-Ex did not cause significant quality changes in apple or bell pepper surfaces during 7 days storage following treatment (P > 0.05). Our results suggest that Sp-Ex could be applied as a system to control pathogens in place of chemical sanitizer washing by the fresh-produce industry.IMPORTANCE Although most fresh-produce processing currently controls pathogens by means of washing with sanitizers, there are still problems such as the generation of harmful substances and changes in product quality. A combination system composed of the Spindle and a 222-nm KrCl excilamp (Sp-Ex) developed in this study reduced pathogens on apple and bell pepper surfaces using sanitizer-free water without altering produce color and texture. This study demonstrates the potential of the Sp-Ex to replace conventional washing with sanitizers, and it can be used as baseline data for practical application by industry. In addition, implementation of the Sp-Ex developed in this study is expected not only to meet consumer preference for fresh, minimally processed produce but also to reduce human exposure to harmful chemicals while being beneficial to the environment.

Increased Resistance of Salmonella enterica Serovar Typhimurium and Escherichia coli O157:H7 to 222-Nanometer Krypton-Chlorine Excilamp Treatment by Acid Adaptation.

In this study, we examined the change in resistance of Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 to 222-nm krypton-chlorine (KrCl) excilamp treatment as influenced by acid adaptation and identified a mechanism of resistance change. In addition, we measured changes in apple juice quality indicators, such as color, total phenols, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, during treatment. Non-acid-adapted and acid-adapted pathogens were induced by growing the cells in tryptic soy broth without dextrose (TSB w/o D) at pH 7.3 and in TSB w/o D at pH 5.0 (adjusted with HCl), respectively. For the KrCl excilamp treatment, acid-adapted pathogens exhibited significantly (P < 0.05) higher D5d values, which indicate dosages required to achieve a 5-log reduction, than those for non-acid-adapted pathogens in both commercially clarified apple juice and phosphate-buffered saline (PBS), and the pathogens in the juice showed significantly (P < 0.05) higher D5d values than those for pathogens in PBS because of the UV-absorbing characteristics of apple juice. Through mechanism identification, it was found that the generation of lipid peroxidation in the cell membrane, inducing cell membrane destruction, was significantly (P < 0.05) lower in acid-adapted cells than in non-acid-adapted cells for the same amount of reactive oxygen species (ROS) generated at the same dose because the ratio of unsaturated to saturated fatty acids (USFA/SFA) in the cell membrane was significantly (P < 0.05) decreased as a result of acid adaptation. Treated apple juice showed no significant (P > 0.05) difference in quality indicators compared to those of untreated controls during treatment at 1,773 mJ/cm2IMPORTANCE There is a need for novel, mercury-free UV lamp technology to replace germicidal lamps containing harmful mercury, which are routinely utilized for UV pasteurization of apple juice. In addition, consideration of the changes in response to antimicrobial treatments that may occur when pathogens are adapted to the acid in an apple juice matrix is critical to the practical application of this technology. Based on this, an investigation using 222-nm KrCl excilamp technology, an attractive alternative to mercury lamps, was conducted. Our study demonstrated increased resistance to 222-nm KrCl excilamp treatment as pathogens adapted to acids, and this was due to changes in reactivity to ROS with changes in the fatty acid composition of the cell membrane. Despite increased resistance, the 222-nm KrCl excilamp achieved pathogen reductions of 5 log or more at laboratory scale without affecting apple juice quality. These results provide valuable baseline data for application of 222-nm KrCl excilamps in the apple juice industry.