Experimental Investigation of Electrospraying Properties Based on Ring Electrode Modification.

Electrospraying uses a high-voltage potential difference to create fine droplets. This study conducts a comparative analysis of the spray pattern and droplet properties using ring electrode parameters. The spray pattern and droplet characteristics are analyzed based on the experimental parameters of the ring electrode. The results show that the cone-jet mode forms quickly for the ring electrode. In addition, as the ring diameter decreases, the ring voltage increases and an increase in the distance between the ring and the nozzle in the bottom direction decreases the Sauter mean diameter and its standard deviation. The optimal conditions for the formation of fine and uniform droplets include a ring diameter of 15 mm, a ring voltage of 7 kV, and a nozzle-to-ring distance of (+) 20 mm.

Health risks of pest control and disinfection workers after the COVID-19 outbreak in South Korea.

The exposure patterns of pest control and disinfection workers have changed after the coronavirus disease 2019 (COVID-19) outbreak, but the health risks of chemical exposure have not been assessed. We identified these workers' chemical exposure patterns and risks before and after the COVID-19 outbreak. We used data conducted between 2018 (pre-pandemic) and 2021 (post-pandemic) from three-year cross-sectional surveys on pest control and disinfection workers. Inhalation and dermal exposure concentrations were estimated using equations based on a biocidal product risk assessment model from the Korean National Institute of Environmental Research. The non-carcinogenic and carcinogenic risks of chemicals were calculated using the United States Environmental Protection Agency risk assessment model. We found that the annual work frequency (50th percentile) of foggers using disinfectants increased the most among all the work types, from 140 uses/year to 176 uses/year after the COVID-19 outbreak. Moreover, all chemicals' non-carcinogenic and carcinogenic risks increased regardless of exposure routes. In the worst scenario (95th percentile), the margin of exposure for citric acid, benzethonium chloride, benzyl-C12-16-alkyldimethyl chlorides, and sodium chlorite of inhalation exposure, and isopropyl alcohol and benzyl-C12-16-alkyldimethyl chlorides of dermal exposure were acceptable (>100) before the COVID-19 outbreak but became unacceptable (<100) after the COVID-19 outbreak. Carcinogenic risks of dichlorvos from inhalation and dermal exposure were above acceptable levels (>10-6) before and after the COVID-19 outbreak but comparatively high after the COVID-19 outbreak. Additionally, significantly more workers experienced health symptoms after the COVID-19 outbreak (p<0.05), with the most common being muscle lethargy (31%), skin/face stinging (28.7%), and breath shortness/neck pain (24.1%).

Rice Basic Helix-Loop-Helix 079 (OsbHLH079) Delays Leaf Senescence by Attenuating ABA Signaling.

Leaf senescence represents the final phase of leaf development and is characterized by a highly organized degenerative process involving the active translocation of nutrients from senescing leaves to growing tissues or storage organs. To date, a large number of senescence-associated transcription factors (sen-TFs) have been identified that regulate the initiation and progression of leaf senescence. Many of these TFs, including NAC (NAM/ATAF1/2/CUC2), WRKY, and MYB TFs, have been implicated in modulating the expression of downstream senescence-associated genes (SAGs) and chlorophyll degradation genes (CDGs) under the control of phytohormones. However, the involvement of basic helix-loop-helix (bHLH) TFs in leaf senescence has been less investigated. Here, we show that OsbHLH079 delays both natural senescence and dark-induced senescence: Overexpression of OsbHLH079 led to a stay-green phenotype, whereas osbhlh079 knockout mutation displayed accelerated leaf senescence. Similar to other sen-TFs, OsbHLH079 showed a gradual escalation in expression as leaves underwent senescence. During this process, the mRNA levels of SAGs and CDGs remained relatively low in OsbHLH079 overexpressors, but increased sharply in osbhlh079 mutants, suggesting that OsbHLH079 negatively regulates the transcription of SAGs and CDGs under senescence conditions. Additionally, we found that OsbHLH079 delays ABA-induced senescence. Subsequent RT-qPCR and dual-luciferase reporter assays revealed that OsbHLH079 downregulates the expression of ABA signaling genes, such as OsABF2, OsABF4, OsABI5, and OsNAP. Taken together, these results demonstrate that OsbHLH079 functions in delaying leaf yellowing by attenuating the ABA responses.

OsMYB7 determines leaf angle at the late developmental stage of lamina joints in rice.

Leaf angle shapes plant architecture, allowing for optimal light interception to maximize photosynthesis and yield, and therefore is a crucial agronomic trait. Here, we show that the rice (Oryza sativa L.) R2R3-type MYB transcription factor OsMYB7 determines leaf angle in a developmental stage-specific manner. OsMYB7-overexpressing lines produced wide-angled leaves and osmyb7 knockout mutants exhibited erect leaves. This phenotype was restricted to the lamina joints at the late developmental stage. In agreement with these observations, OsMYB7 was preferentially expressed in the lamina joints of post-mature leaves. Since OsMYB7 homologs are transcriptional repressors of lignin biosynthesis, we examined whether OsMYB7 might inhibit thickening of secondary cell walls. Although OsMYB7 repressed lignin biosynthesis, it enhanced thickening of sclerenchyma cell walls by elevating cellulose contents at the lamina joints. Furthermore, we found that OsMYB7 affects endogenous auxin levels in lamina joints, and the adaxial cells of lamina joints in OsMYB7-overexpressing lines and osmyb7 knockout mutants exhibited enhanced and reduced elongation, respectively, compared to the wild type. These results suggest that OsMYB7 promotes leaf inclination partially through decreasing free auxin levels and promoting cell elongation at the adaxial side of lamina joints.

Asymmetric Spray Characteristics According to Y-Jet Nozzle Orifice Shape and Spray Conditions.

The Y-jet nozzle is a twin-fluid nozzle that has a larger operating range and simpler structure than other twin-fluid nozzles. Furthermore, it offers outstanding atomization quality even at low flow rates, mak ing it simple to atomize viscous liquids. However, because of the structure of the Y-jet nozzle, having an asymmetrical spray pattern is limited. Most existing experimental studies focused on the orifice diameter and mixing tube length. In this study, two types of elliptical nozzles and one type of circular nozzle were tested. We found that the elliptical nozzle's asymmetric spray characteristics are different from those of the circular type. Furthermore, it was demonstrated that the spray characteristics were different even in ellipsoids, with only the major and minor axes differing.

Evaluation of effectiveness and improvement factors of occupational health and safety management system in the Republic of Korea Navy based on AHP-entropy and IPA.

The Republic of Korea Navy (ROKN) has applied Occupational Health and Safety Management System (OHSMS), but the effectiveness of OHSMS is being questioned due to continuous industrial accidents that continue to occur. Although OHSMS, which has been generally applied in enterprises, has more potential for improper implementation in the military, there are few studies on OHSMS in the military. Therefore, this study verified the effectiveness of OHSMS in the ROKN and derived improvement factors. This study was conducted in a two-step process. First, we surveyed 629 workers at the ROKN workplaces to confirm the effectiveness of OHSMS by comparing occupational health and safety (OHS) efforts according to whether OHSMS was applied and the period of application. Second, 29 naval OHSMS experts evaluated the factors for improving OHSMS using two decision-making tools: Analytic Hierarchy Process (AHP)-entropy and Importance-Performance Analysis (IPA). The study results indicate that the OHS efforts of OHSMS-applied workplaces were similar to that of unapplied. Also, no better OHS efforts were identified in workplaces with more extended OHSMS application periods. There were five improvement factors of OHSMS applied to the ROKN workplaces, with the highest weight in the following order: consultation and participation of workers; resources; competence; hazard identification and risk assessment; and organizational roles, responsibilities, and authorities. The effectiveness of OHSMS in the ROKN was insufficient. Therefore, the ROKN needs focused improvement efforts on the five requirements to implement OHSMS practically. These results can be helpful information for the ROKN to apply OHSMS more effectively for industrial safety.

Spray Mode and Monodisperse Droplet Properties of an Electrospray.

As a method of fluid atomization via application of a high voltage, electrospraying forms more uniform droplets than other spraying modes. This approach involves various spraying modes depending on the applied voltage. Most previous studies on electrospraying focused on the cone jet mode, which has limited applications since the applied voltage has a narrow range. To overcome this limitation, it is necessary to consider alternative spray modes, which require an in-depth understanding of their characteristics. To compare different spray modes, an investigation was conducted based on experimental parameters and fluid properties. In this study, a total of nine modes were identified, and the droplet characteristics in four modes were compared. The maximum deviation of the Sauter mean diameter (SMD) between the spray modes was approximately 1.7 times, and the SMD standard deviation was up to 2.8 times. In addition, the conditions required to realize Coulomb fission and monodisperse distribution depending on the Rayleigh critical charge (RSD < 6.76) were compared and examined.

Amplification of LTRs of extrachromosomal linear DNAs (ALE-seq) identifies two active Oryco LTR retrotransposons in the rice cultivar Dongjin.

Long terminal repeat retrotransposons (LTR-RTs) make up a considerable portion of plant genomes. New insertions of these active LTR-RTs modify gene structures and functions and play an important role in genome evolution. Therefore, identifying active forms of LTR-RTs could uncover the effects of these elements in plants. Extrachromosomal linear DNA (eclDNA) forms during LTR-RT replication; therefore, amplification LTRs of eclDNAs followed by sequencing (ALE-seq) uncover the current transpositional potential of the LTR-RTs. The ALE-seq protocol was validated by identification of Tos17 in callus of Nipponbare cultivar. Here, we identified two active LTR-RTs belonging to the Oryco family on chromosomes 6 and 9 in rice cultivar Dongjin callus based on the ALE-seq technology. Each Oryco family member has paired LTRs with identical sequences and internal domain regions. Comparison of the two LTR-RTs revealed 97% sequence identity in their internal domains and 65% sequence identity in their LTRs. These two putatively active Oryco LTR-RT family members could be used to expand our knowledge of retrotransposition mechanisms and the effects of LTR-RTs on the rice genome.

Natural alleles of CIRCADIAN CLOCK ASSOCIATED1 contribute to rice cultivation by fine-tuning flowering time.

The timing of flowering is a crucial factor for successful grain production at a wide range of latitudes. Domestication of rice (Oryza sativa) included selection for natural alleles of flowering-time genes that allow rice plants to adapt to broad geographic areas. Here, we describe the role of natural alleles of CIRCADIAN CLOCK ASSOCIATED1 (OsCCA1) in cultivated rice based on analysis of single-nucleotide polymorphisms deposited in the International Rice Genebank Collection Information System database. Rice varieties harboring japonica-type OsCCA1 alleles (OsCCA1a haplotype) flowered earlier than those harboring indica-type OsCCA1 alleles (OsCCA1d haplotype). In the japonica cultivar "Dongjin", a T-DNA insertion in OsCCA1a resulted in late flowering under long-day and short-day conditions, indicating that OsCCA1 is a floral inducer. Reverse transcription quantitative PCR analysis showed that the loss of OsCCA1a function induces the expression of the floral repressors PSEUDO-RESPONSE REGULATOR 37 (OsPRR37) and Days to Heading 8 (DTH8), followed by repression of the Early heading date 1 (Ehd1)-Heading date 3a (Hd3a)-RICE FLOWERING LOCUS T 1 (RFT1) pathway. Binding affinity assays indicated that OsCCA1 binds to the promoter regions of OsPRR37 and DTH8. Naturally occurring OsCCA1 alleles are evolutionarily conserved in cultivated rice (O. sativa). Oryza rufipogon-I (Or-I) and Or-III type accessions, representing the ancestors of O. sativa indica and japonica, harbored indica- and japonica-type OsCCA1 alleles, respectively. Taken together, our results demonstrate that OsCCA1 is a likely domestication locus that has contributed to the geographic adaptation and expansion of cultivated rice.

Viscosity Effect on the Electrospray Characteristics of Droplet Size and Distribution.

Electrostatic spraying is a method of atomizing a fluid using a high voltage as an atomization auxiliary device, and various spraying modes exist according to experimental parameters and viscosity. A maximum of 11 spray modes were identified according to the changes in the applied voltage and flow rate. To produce fine droplets and a uniform size, which are the advantages of electrostatic spraying, in this experiment, the Sauter mean diameter (SMD) and SMD distribution were evaluated in each spray mode of electrostatic spraying. By comparing the other spray modes with the cone jet mode, it was confirmed that the maximum difference of the SMD was less than 1.5 times and the standard deviation of the rotated and pulsed jets was 2.5 times or more. In the cone shape range, the SMD and SMD distribution according to the applied voltage confirmed that the droplet size was the smallest in the middle of the cone jet mode, and the droplet distribution was also narrow. In the cone jet mode, the droplet size increased linearly with the viscosity and flow rate. In addition, the droplet distribution range was distinctive depending on the type of fluid. In the case of the relationship between the droplet size and current, it was proven that the higher the viscosity, the higher the current value for the same SMD; furthermore, the difference in the current-SMD increase rate was insignificant. Through experiments, this work presents experimental data of SMD, SMD distribution, and current-SMD in electrostatic spray experiments under various conditions.

Effect of the Oxygen Concentration and Temperature on Thermal Decomposition of N2O in an Inert Gas.

Nitrous oxide (N2O) is one of the greenhouse gases that contribute to global warming. But, there are few methods for controlling N2O directly. It is essential to reduce N2O to solve environmental problems. In this study, we investigate the O2 concentration dependence of N2O decomposition under an argon-based gas mixture in a high-temperature thermal reactor. The gas concentrations are calculated using CHEMKIN. The results confirm that more N2O is converted to N2 or NO at lower O2 concentrations. Therefore, the conversion process is hindered by increasing the O2 concentration. We propose a modified parameter of N2O decomposition, and it is employed in the CHEMKIN calculations. With the modified parameter, the experimental results are in a similar tendency to the calculated results.

Effects of Y-Jet Nozzle Mixing Chamber Length and the GLR on Spatial Asymmetric Spray.

The Y-jet nozzle is simpler to design than other twin-fluid nozzles and has various advantages such as having a wide turn-down ratio. For this reason, it is mainly used for industrial boilers and combustion. The Y-jet nozzle comprises liquid and assist gas supply ports, a mixing chamber, where two fluids (liquid and the assist gas) are mixed, and an exit orifice. The time it takes to mix the two fluids in the mixing chamber depends on the length of the chamber, which determines the spray and particulate properties. Therefore, the mixing chamber is one of the most important factors when designing the Y-jet nozzle. The gas to liquid mass flow rate ratio (GLR) is an important variable that affects the spray characteristics of the Y-jet nozzle. In this work, a laboratory-scale Y-jet nozzle spray experimental setup was developed to perform spray experiments. In particular, we observe the spray properties in the front and right directions to observe spatial spray properties. Significant results were obtained depending on the length of the mixing chamber, the spray pattern, and the Sauter mean diameter according to the GLR. We found that a mixing chamber with longer length reduces the effect of asymmetric spray and confirm that the central axis of spray is more stable.

The Rice Basic Helix-Loop-Helix 79 (OsbHLH079) Determines Leaf Angle and Grain Shape.

Changes in plant architecture, such as leaf size, leaf shape, leaf angle, plant height, and floral organs, have been major factors in improving the yield of cereal crops. Moreover, changes in grain size and weight can also increase yield. Therefore, screens for additional factors affecting plant architecture and grain morphology may enable additional improvements in yield. Among the basic Helix-Loop-Helix (bHLH) transcription factors in rice (Oryza sativa), we found an enhancer-trap T-DNA insertion mutant of OsbHLH079 (termed osbhlh079-D). The osbhlh079-D mutant showed a wide leaf angle phenotype and produced long grains, similar to the phenotypes of mutants with increased brassinosteroid (BR) levels or enhanced BR signaling. Reverse transcription-quantitative PCR analysis showed that BR signaling-associated genes are largely upregulated in osbhlh079-D, but BR biosynthesis-associated genes are not upregulated, compared with its parental japonica cultivar 'Dongjin'. Consistent with this, osbhlh079-D was hypersensitive to BR treatment. Scanning electron microscopy revealed that the expansion of cell size in the adaxial side of the lamina joint was responsible for the increase in leaf angle in osbhlh079-D. The expression of cell-elongation-associated genes encoding expansins and xyloglucan endotransglycosylases/hydrolases increased in the lamina joints of leaves in osbhlh079-D. The regulatory function of OsbHLH079 was further confirmed by analyzing 35S::OsbHLH079 overexpression and 35S::RNAi-OsbHLH079 gene silencing lines. The 35S::OsbHLH079 plants showed similar phenotypes to osbhlh079-D, and the 35S::RNAi-OsbHLH079 plants displayed opposite phenotypes to osbhlh079-D. Taking these observations together, we propose that OsbHLH079 functions as a positive regulator of BR signaling in rice.