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Molybdenum disulfide (MoS2), a semiconducting two-dimensional layered transition metal dichalcogenide (2D TMDC), with attractive properties enables the opening of a new electronics era beyond Si. However, the notoriously high contact resistance (RC) regardless of the electrode metal has been a major challenge in the practical applications of MoS2-based electronics. Moreover, it is difficult to lower RC because the conventional doping technique is unsuitable for MoS2 due to its ultrathin nature. Therefore, the metal–insulator–semiconductor (MIS) architecture has been proposed as a method to fabricate a reliable and stable contact with low RC. Herein, we introduce a strategy to fabricate MIS contact based on atomic layer deposition (ALD) to dramatically reduce the RC of single-layer MoS2 field effect transistors (FETs). We utilize ALD Al2O3 as an interlayer for the MIS contact of bottom-gated MoS2 FETs. Based on the Langmuir isotherm, the uniformity of ALD Al2O3 films on MoS2 can be increased by modulating the precursor injection pressures even at low temperatures of 150 °C. We discovered, for the first time, that film uniformity critically affects RC without altering the film thickness. Additionally, we can add functionality to the uniform interlayer by adopting isopropyl alcohol (IPA) as an oxidant. Tunneling resistance across the MIS contact is lowered by n-type doping of MoS2 induced by IPA as the oxidant in the ALD process. Through a highly uniform interlayer combined with strong doping, the contact resistance is improved by more than two orders of magnitude compared to that of other MoS2 FETs fabricated in this study. [ABSTRACT FROM AUTHOR]

The etch rate uniformity in photoresist etching was monitored using multi-channel optical emission spectroscopy (OES) and a spatially resolved etch rate model incorporating radical and ion etching characteristics. The F radical densities at various locations were estimated using 8-channel OES and applied to a radical-spontaneous etch rate model to examine the impact of radicals on the etch rate. The ion fluxes were measured using a scanning floating harmonic probe for an ion-enhanced etch rate model to investigate the effect of ions on the etch rate. A combined etch rate model was proposed to explain the effects on both radical and ion etching characteristics, and the etch rates and etch rate uniformities predicted by the model were quantitatively compared with the measured values. The calculated R-squared score (R2) and the mean absolute percentage error (MAPE) of the etch rates predicted by the model were 0.99 and 1.3%, respectively. The etch rate uniformities predicted by the model showed good accuracy with R2 of 0.99 and MAPE of 12.0% compared to the measured values, and the combined etch rate model also successfully predicted the distribution of the etch rate. This study demonstrates that multi-channel OES and the developed model can quantitatively predict the etch rate distribution of plasma etching processes. [ABSTRACT FROM AUTHOR]

Background: Chuna manual therapy (CMT), a Korean manual therapy technique predominantly used for treating low back pain (LBP) and related disorders, lacks well-conceived research focusing on its comparative effectiveness, safety, and economic evaluation, particularly with respect to complex CMT with established CMT diagnostic algorithms. This study aims to illustrate a protocol for a randomized clinical study for comparative effectiveness and cost-effectiveness of complex CMT with simple CMT and usual care. Methods: This is a protocol for a three-armed, multicenter, assessor-blinded, pragmatic, randomized controlled trial study. A total of 81 patients suffering from non-acute LBP with pelvic biomechanical lesions (PBL), characterized by a pain duration of at least two weeks and a Numeric Rating Scale (NRS) score of 5 or higher, will be recruited from two Korean medicine hospitals. These participants will be randomly assigned to one of three groups: complex CMT plus usual care (UC; n = 27), simple CMT plus UC (n = 27), or UC groups (n = 27). They will undergo treatment for 4 weeks, and follow-up assessments will be performed 8 weeks after treatment completion. The primary outcome will be the NRS score of LBP, and secondary outcomes will include the Oswestry Disability Index, Patient Global Impression of Change, credibility and expectancy questionnaire, three-dimensional posture analysis indicators, quality of life assessment, economic evaluation, and safety assessments. Discussion: This will be the first study to assess the comparative effectiveness, safety, and cost-effectiveness of complex CMT compared to UC and simple/complex CMT in patients with LBP and PBL. We will also analyze useful diagnostic methods to help in clinical practice for CMT diagnosis. Trial registration: Clinical Research Information Service (CRIS), KCT0009210. Registered on February 28, 2024. [ABSTRACT FROM AUTHOR]

(1) Background: Various machine learning techniques were used to predict hypertension in Korean adults aged 20 and above, using a range of body composition indicators. Muscle and fat components of body composition are closely related to hypertension. The aim was to identify which body composition indicators are significant predictors of hypertension for each gender; (2) Methods: A model was developed to classify hypertension using six different machine learning techniques, utilizing age, BMI, and body composition indicators such as body fat mass, lean mass, and body water of 2906 Korean men and women; (3) Results: The elastic-net technique demonstrated the highest classification accuracy. In the hypertension prediction model, the most important variables for men were age, skeletal muscle mass (SMM), and body fat mass (BFM), in that order. For women, the significant variables were age and BFM. However, there was no difference between soft lean mass and SMM; (4) Conclusions: Hypertension affects not only BFM but also SMM in men, whereas in women, BFM has a stronger effect than SMM. [ABSTRACT FROM AUTHOR]

Background: Menopause induces various health problems and is associated with obesity, but the association between menopausal status and obesity is unclear due to several confounding factors, such as aging and reduced physical activity. The objective of this study was to examine the association of menopausal status with anthropometric indices and body composition indices in South Korean women. Methods: In this cross-sectional study, a total of 734 subjects (297 postmenopausal women, 437 premenopausal women) from five university hospitals in South Korea were included. A binary logistic regression analysis was performed to examine the association of menopause with anthropometric indices and body composition indices. Results: Height, body mass index, waist-to-height ratio, waist-to-hip ratio, and neck, armpit, chest, rib, waist, iliac, and hip circumferences were associated with menopausal status in the crude analysis, but these associations disappeared in the adjusted models. Among the body composition indices, menopausal status was strongly associated with total body water, skeletal muscle mass, body fat mass, and body fat percentage in the crude analysis. However, the associations with body fat mass and body fat percentage disappeared in the adjusted models. Only the associations with total body water and skeletal muscle mass remained in the adjusted models. Conclusion: Most of the anthropometric indices and body composition indices were not associated with menopausal status, but total body water and skeletal muscle mass were significantly lower in postmenopausal women than in premenopausal women. [ABSTRACT FROM AUTHOR]

Depression is heritable, differs by sex, and has environmental risk factors such as cigarette smoking. However, the effect of single nucleotide polymorphisms (SNPs) on depression through cigarette smoking and the role of sex is unclear. In order to examine the association of SNPs with depression and smoking in the UK Biobank with replication in the COPDGene study, we used counterfactual-based mediation analysis to test the indirect or mediated effect of SNPs on broad depression through the log of pack-years of cigarette smoking, adjusting for age, sex, current smoking status, and genetic ancestry (via principal components). In secondary analyses, we adjusted for age, sex, current smoking status, genetic ancestry (via principal components), income, education, and living status (urban vs. rural). In addition, we examined sex-stratified mediation models and sex-moderated mediation models. For both analyses, we adjusted for age, current smoking status, and genetic ancestry (via principal components). In the UK Biobank, rs6424532 [LOC105378800] had a statistically significant indirect effect on broad depression through the log of pack-years of cigarette smoking (p = 4.0 × 10−4) among all participants and a marginally significant indirect effect among females (p = 0.02) and males (p = 4.0 × 10−3). Moreover, rs10501696 [GRM5] had a marginally significant indirect effect on broad depression through the log of pack-years of cigarette smoking (p = 0.01) among all participants and a significant indirect effect among females (p = 2.2 × 10−3). In the secondary analyses, the sex-moderated indirect effect was marginally significant for rs10501696 [GRM5] on broad depression through the log of pack-years of cigarette smoking (p = 0.01). In the COPDGene study, the effect of an SNP (rs10501696) in GRM5 on depressive symptoms and medication was mediated by log of pack-years (p = 0.02); however, no SNPs had a sex-moderated mediated effect on depressive symptoms. In the UK Biobank, we found SNPs in two genes [LOC105378800, GRM5] with an indirect effect on broad depression through the log of pack-years of cigarette smoking. In addition, the indirect effect for GRM5 on broad depression through smoking may be moderated by sex. These results suggest that genetic regions associated with broad depression may be mediated by cigarette smoking and this relationship may be moderated by sex. [ABSTRACT FROM AUTHOR]

We established a protocol for the traditional Korean medicine examination (KME) and methodically gathered data following this protocol. Potential indicators for KME were extracted through a literature review; the first KME protocol was developed based on three rounds of expert opinions. The first KME protocol's feasibility was confirmed, and data were collected over four years from traditional Korean medicine (KM) hospitals, focusing on healthy adults, using the final KME protocol. A literature review identified 175 potential core indicators, condensed into 73 indicators after three rounds of expert consultation. The first KME protocol, which was categorized under questionnaires and medical examinations, was developed after the third round of expert opinions. A pilot study using the first KME protocol was conducted to ensure its validity, leading to modifications resulting in the development of the final KME protocol. Over four years, data were collected from six KM hospitals, focusing on healthy adults; we obtained a dataset comprising 11,036 healthy adults. This is the first protocol incorporating core indicators of KME in a quantitative form and systematically collecting data. Our protocol holds potential merit in evaluating predisposition to diseases or predicting diseases. [ABSTRACT FROM AUTHOR]

This study aims to develop and validate the Principal Competency Inventory (PCI), an instrument used to assess a principal's leadership competencies that promote student learning in South Korea. An extensive review of prior work was conducted to understand the theoretical foundation related to school leadership and the competency construct of the PCI derived from the Behavioural Event Interview of principals. Then, the psychometric procedures used in developing and validating the PCI were followed. The significance of this study and its practical implications for the use of this new instrument was discussed. From a theoretical and practical standpoint, this study contributes to the school leadership field by describing development and validation procedures, identifying where evidence of the reliable assessment instrument is lacking, and utilising the advantage of the competency-based framework. Also, the analysis of this study provides international perspectives about school leadership practices, thus supplementing the prior Western-focused literature in this field. In addition, this study offers useful information for policymakers and principal leadership development program designers who want to assess and evaluate principal leadership competency. [ABSTRACT FROM AUTHOR]

SUMMARY: Sorghum anthracnose caused by the fungus Colletotrichum sublineola (Cs) is a damaging disease of the crop. Here, we describe the identification of ANTHRACNOSE RESISTANCE GENES (ARG4 and ARG5) encoding canonical nucleotide‐binding leucine‐rich repeat (NLR) receptors. ARG4 and ARG5 are dominant resistance genes identified in the sorghum lines SAP135 and P9830, respectively, that show broad‐spectrum resistance to Cs. Independent genetic studies using populations generated by crossing SAP135 and P9830 with TAM428, fine mapping using molecular markers, comparative genomics and gene expression studies determined that ARG4 and ARG5 are resistance genes against Cs strains. Interestingly, ARG4 and ARG5 are both located within clusters of duplicate NLR genes at linked loci separated by ~1 Mb genomic region. SAP135 and P9830 each carry only one of the ARG genes while having the recessive allele at the second locus. Only two copies of the ARG5 candidate genes were present in the resistant P9830 line while five non‐functional copies were identified in the susceptible line. The resistant parents and their recombinant inbred lines carrying either ARG4 or ARG5 are resistant to strains Csgl1 and Csgrg suggesting that these genes have overlapping specificities. The role of ARG4 and ARG5 in resistance was validated through sorghum lines carrying independent recessive alleles that show increased susceptibility. ARG4 and ARG5 are located within complex loci displaying interesting haplotype structures and copy number variation that may have resulted from duplication. Overall, the identification of anthracnose resistance genes with unique haplotype stucture provides a foundation for genetic studies and resistance breeding. Significance Statement: We identified two tightly linked NLR genes conferring resistance to the sorghum anthracnose disease that is a major challenge to production of the crop globally. The two genes were identified among clusters of highly similar duplicate genes with resistant and susceptible lines having unique haplotypes, and amino acid substitutions in key positions, leading to changes in tertiary protein structure and disease resistance function. The results provide new opportunities for resistance breeding and genetic and molecular studies. [ABSTRACT FROM AUTHOR]

Hydrogen is attracting attention as a low-carbon fuel. In particular, economical hydrogen production technologies without carbon emissions are gaining increasing attention. Recently, alkaline thermal treatment (ATT) has been proposed to reduce carbon emissions by capturing carbon in its solid phase during hydrogen production. By adding an alkali catalyst to the conventional thermochemical hydrogen production reaction, ATT enables carbon capture through the reaction of an alkali catalyst and carbon. In this study, a thermodynamic feasibility evaluation was carried out, and the effects of the process conditions for ATT with wheat straw grass (WSG) as biomass were investigated using Aspen Plus software V12.1. First, an ATT process model was developed, and basic thermodynamic equilibrium compositions were obtained in various conditions. Then, the effects of the process parameters of the reactor temperature and the mass ratio of NaOH/WSG (alkali/biomass, A/B value) were analyzed. Finally, the product gas compositions, process efficiency, and amount of carbon capture were evaluated. The results showed that the ATT process could be an efficient hydrogen production process with carbon capture, and the optimal process conditions were a reactor temperature of 800 °C, an A/B value of three, and a flow rate of steam of 6.9 × 10−5 L/min. Under these conditions, the maximum efficiency and the amount of carbon dioxide captured were 56.9% and 28.41 mmol/g WSG, respectively. [ABSTRACT FROM AUTHOR]

Dissecting the diversity of midbrain dopamine (DA) neurons by optotagging is a promising addition to better identify their functional properties and contribution to motivated behavior. Retrograde molecular targeting of DA neurons with specific axonal projection allows further refinement of this approach. Here, we focus on adult mouse DA neurons in the substantia nigra pars compacta (SNc) projecting to dorsal striatum (DS) by demonstrating the selectivity of a floxed AAV9‐based retrograde channelrhodopsin‐eYFP (ChR‐eYFP) labeling approach in DAT‐cre mice. Furthermore, we show the utility of a sparse labeling version for anatomical single‐cell reconstruction and demonstrate that ChR‐eYFR expressing DA neurons retain intrinsic functional properties indistinguishable from conventionally retrogradely red‐beads‐labeled neurons. We systematically explore the properties of optogenetically evoked action potentials (oAPs) and their interaction with intrinsic pacemaking in this defined subpopulation of DA neurons. We found that the shape of the oAP and its first derivative, as a proxy for extracellularly recorded APs, is highly distinct from spontaneous APs (sAPs) of the same neurons and systematically varies across the pacemaker duty cycle. The timing of the oAP also affects the backbone oscillator of the intrinsic pacemaker by introducing transient "compensatory pauses". Characterizing this systematic interplay between oAPs and sAPs in defined DA neurons will also facilitate a refinement of DA neuron optotagging in vivo. [ABSTRACT FROM AUTHOR]

Recently, the concept of a circular economy for carbon neutrality is emerging. In particular, waste plastics are one of the key wastes, and efforts are being made to recycle them as energy rather than dispose of them. Accordingly, the technology of producing and utilizing pyrolysis oil from waste plastics attracts attention. As it is an early stage of technology development, however, there are not many demonstrations and papers that analyze the technology broadly. The goal of this study is to propose building a circular economy on a university campus through waste plastic pyrolysis oil technology. To show its feasibility, waste plastic pyrolysis oil technology is analyzed comprehensively from economic, environmental, and policy perspectives using the scenario analysis technique on the university campus level. A methodology of the scenario analysis technique enables predicting the uncertainties. Since plastic pyrolysis oil technologies and carbon neutrality are accompanied by many uncertainties, this technique is expected to be an appropriate methodology for this study. First, the amount of pyrolysis oil production from waste plastics from the campus is estimated. Then, the cost and carbon emissions from waste plastics are estimated if the pyrolysis oil technology is used instead of the traditional waste disposal process. As a result, the total economic profits of up to 425,484,022 won/year (354,570.01 $/year) are expected when a circular economy is built using waste plastic pyrolysis oil. In addition, it is also confirmed that greenhouse gas (GHG) emissions can be reduced by up to 840,891 kgCO2eq/year. The waste plastic pyrolysis oil satisfies Korea's gas pollutant standards and is consistent with the GHG reduction policy. It can be concluded that building a circular economy at the university campus level using waste plastic pyrolysis oil technology is suitable from economic, environmental, and policy perspectives. [ABSTRACT FROM AUTHOR]

In this paper, we prove two rigidity results of hypersurfaces in n-dimensional weighted Riemannian manifolds with weighted scalar curvature bounded from below. Firstly, we establish a splitting theorem for the n-dimensional weighted Riemannian manifold via a weighted area-minimizing hypersurface. Secondly, we observe the topological invariance of the weighted stable hypersurface when the ambient weighted scalar curvature is bounded from below by a positive constant. In particular, we derive a non-existence result for a weighted stable hypersurface. [ABSTRACT FROM AUTHOR]

Background: As chromatographic techniques have advanced, many articles that analyze the constituting compounds of medicinal materials have been published in relation to Northeast Asian traditional medicine, including traditional Chinese medicine (TCM). TM-MC was launched in 2015, providing information about the chemical compounds in medicinal materials from chromatographic articles in PubMed. Since 2015, through continuous curation efforts, we have now released TM-MC 2.0 with significant improvements to the quantity and quality of the data (https://tm-mc.kr). Description: TM-MC 2.0 contains 635 medicinal materials, 34,107 chemical compounds (21,306 identified and de-duplicated), 13,992 targets, 27,997 diseases, and 5,075 prescriptions (2,393 de-duplicated by name). The database provides the largest number of identified compounds for medicinal materials listed in the pharmacopoeia compared to all TCM databases. In particular, marker compounds of medicinal materials and many newly discovered compounds were added through the manual curation of recent chromatographic articles. Conclusion: TM-MC 2.0 provides the largest collection of information about the chemical compounds of the medicinal materials listed in the Korean, Chinese, and Japanese pharmacopoeias. Our database can be utilized for network pharmacology in traditional medicine and for the compound screening of medicinal materials for modern drug discovery. [ABSTRACT FROM AUTHOR]

Vegetation constitutes the primary component of terrestrial ecosystems and plays a crucial role in examining global climate change and its impacts. Assessing vegetation dynamics over significant periods of time can provide critical information on changes in vegetation cover and regional climate. Satellite-based remote sensing products offer a unique opportunity to analyze these changes at a country scale. South Korea has a unique history of forest regeneration, and studying this relationship provides an opportunity to examine its impact. To achieve this, we employ the vegetation–precipitation relationship using time series segmentation on residual trends (TSS-RESTREND), a statistical method that calculates the correlation between the annual maximum vegetation index and cumulative rainfall. This method helps identify time-step changes related to structural changes in the ecosystem. Using the enhanced vegetation index (EVI) and rainfall, this study aims to uncover the underlying dynamics and driving forces behind observed ecosystem changes, facilitating a deeper comprehension of the intricate interactions between vegetation and precipitation through the application of TSS-RESTREND. The findings increase knowledge of the complex relationship between vegetation growth and rainfall, given the country's commendable forest regeneration program, even in the face of rapid urbanization. Moreover, the integration of finer resolution land cover images derived from in situ data not only provides a nuanced understanding of vegetation dynamics across diverse regions, but also underscores the critical need for continued collection of in situ data to provide more accurate and comprehensive analyses. The findings underline the pivotal role played by land resource management practices and underscores the significance of implementing adaptive conservation strategies, thereby contributing to the preservation of a stable and sustainable vegetation cover. The findings serve as a call for the ecosystem monitoring and strategic adaptation required to examine the environmental and ecosystem structural changes in the region. This study sheds light on the critical relationship between land management practices, environmental sustainability, and the resilience of the region's vegetation amidst an ever-changing landscape. [ABSTRACT FROM AUTHOR]

2–(1H–1,2,4–Triazol–3–yl)phenol (CAT–1) was used as an organocatalyst for the coupling reaction of CO2 and epoxides at an ambient temperature and atmospheric CO2 pressure (1 bar). This compound has a structure in which a hydrogen bond donor, a hydrogen bond acceptor, and another hydrogen bond donor are adjacent in sequence in a molecule. The binary catalytic system of CAT–1/nBu4NI showed TON = 19.2 and TOF = 1.60 h−1 under 1 bar CO2 at room temperature within 12 h using 2–butyloxirane. Surprisingly, the activity of CAT–1, in which phenol and 1H–1,2,4–triazole are chemically linked, showed a much greater synergistic effect than when simply mixing the same amount of phenol and 1H–1,2,4–triazole under the same reaction conditions. In addition, our system showed a broad terminal and internal epoxide substrate scope. [ABSTRACT FROM AUTHOR]

Atomic layer deposition (ALD) of multicomponent materials is challenging because the growth characteristics often deviate from what is expected due to the difference in surface characteristics of heterogeneous and single materials, resulting in undesired thickness or properties. For metal oxides, the growth characteristics highly rely on the surface hydroxyl groups, which play a role as the reactive site. Thus, studying the reaction mechanism of a precursor on hydroxyl-terminated heterogeneous surfaces is important for understanding the nonideal growth of ternary oxide. Here, we investigated the correlation between hydroxyl and the growth of ALD TiSiOx depending on temperature, analyzing infrared spectra, and chemical compositions. The results show that large amounts of hydroxyl are detected in TiSiOx deposited at 100 °C, where the adsorption of H2O on Ti–O–Si bonds is favorable. It leads to higher growth per cycle (GPC) than the estimated value. In contrast, the hydroxyl disappears at 200 °C due to dehydroxylation, resulting in lower GPC. Differences in hydroxyl also influence the film density as revealed in x-ray reflection spectra, which is related to the film qualities (e.g., elastic modulus and dry etch rates). This work provides insight into how to control hydroxyl in the ALD of ternary oxides, which is susceptible to hydroxyl incorporation, leading to undesired growth characteristics. [ABSTRACT FROM AUTHOR]

Background: Thoracic acute aortic syndrome (AAS) and non-ST elevation myocardial infarction (NSTEMI) have similar clinical presentations, making them difficult to differentiate. This study aimed to identify useful biomarkers for the differential diagnosis of thoracic AAS and NSTEMI. Methods: This was a retrospective observational study. Participants: consecutive adult patients who visited the emergency department for acute chest pain between January 2015 and December 2021 diagnosed with thoracic AAS or NSTEMI. Clinical variables, including D-dimer (μg/mL) and high-sensitivity troponin T (ng/mL, hs-TnT) levels, were compared between the groups. Results: A total of 52 (30.1%) and 121 (69.9%) patients were enrolled in the thoracic AAS and NSTEMI groups, respectively. Logistic regression analysis revealed that the D-dimer to hs-TnT (D/T) ratio (odds ratio (OR), 1.038; 95% confidence interval (CI), 1.020–1.056; p < 0.001) and the thrombolysis in myocardial infarction (TIMI) score (OR, 0.184; 95% CI, 0.054–0.621; p = 0.006) were associated with thoracic AAS. The D/T ratio had an area under the receiver operating characteristic curve (AUC) of 0.973 (95% CI, 0.930–0.998), and the optimal cutoff value was 81.3 with 91.4% sensitivity and 96.2% specificity. The TIMI score had an AUC of 0.769 (95% CI, 0.644–0.812), and the optimal cutoff value was 1.5 with 96.7% sensitivity and 38.5% specificity. Conclusion: the D/T ratio may be a simple and useful parameter for differentiating thoracic AAS from NSTEMI. [ABSTRACT FROM AUTHOR]

This paper presents a K-band CMOS cross-coupled pair voltage-controlled oscillator (VCO) that utilizes the varactor-only capacitor network. The proposed circuit features low parasitics and a compact capacitor network, such that the varactor in the analog tuning path directly affects the oscillation frequency with a large gain of the VCO, and the varactor in the digital tuning path results in minimal noise sources, thus achieving low phase noise for the automotive FMCW radar application. This VCO was designed using TSMC 65 nm technology, and the post-layout simulation results show a stable oscillation across 18–19.2 GHz, a minimum phase noise of −105.9 and −128 dBc/Hz at 1- and 10-MHz offset frequencies while dissipating 21 mW of power from a 1 V supply. Furthermore, no notable variations in phase noise are observed across the oscillation frequency tuning range. It reveals a figure of merit (FOM) of −178.3 dBc/Hz while using a varactor-only capacitor array and occupying a small chip area. [ABSTRACT FROM AUTHOR]

Background: Alarmins S100A8 and S100A9 are recognized as hallmarks of severe COVID-19 and are primarily produced in myeloid cells, such as monocytes and neutrophils. As single-cell RNA-sequencing (scRNA-seq) data from patients with COVID-19 revealed the expression of S100A8/A9 in lymphoid cells in patients with severe COVID-19. Objective: We investigated the characteristics of lymphoid cells expressing S100A8/A9 in COVID-19 patients. Methods: Publicly available scRNA-seq data from patients with mild (N = 12) or severe (N = 7) COVID-19 were reanalyzed. The data were further divided into the following two groups based on the time of sample collection (from infection-onset): within 6 days (early phase) and after 6 days (late phase). Differential expression and gene set enrichment analyses were performed between S100A8/A9High and S100A8/A9Low lymphoid cells. Finally, cell-cell interaction analysis was performed to investigate the role of lymphoid cells expressing high levels of S100A8/A9 in COVID-19. Results: S100A8/A9 overexpression was observed in lymphoid cells, including B cells, T cells, and NK cells, in patients with severe COVID-19 (compared to patients with mild COVID-19). Cells exhibiting strong interferon/cytokine responses were found to be associated with the severity of COVID-19. Furthermore, differences in S100A8/A9-TLR4/RAGE interactions were confirmed between patients with severe and mild disease. Conclusions: Lymphoid cells overexpressing S100A8/A9 contribute to the dysregulation of the innate immune response in patients with severe COVID-19, specifically during the early phase of infection. This study fosters a better understanding of the hyper-induction of pro-inflammatory cytokine expression and the generation of a cytokine storm in response to COVID-19 infection. [ABSTRACT FROM AUTHOR]

Recent advances in convolutional neural network (CNN)-based object detection have a trade-off between accuracy and computational cost in various industrial tasks and essential consideration. However, the fully convolutional one-stage detector (FCOS) demonstrates low accuracy compared with its computational costs owing to the loss of low-level information. Therefore, we propose a module called a dual-path lightweight module (DLM) that efficiently utilizes low-level information. In addition, we propose a DLMFCOS based on DLM to achieve an optimal trade-off between computational cost and detection accuracy. Our network minimizes feature loss by extracting spatial and channel information in parallel and implementing a bottom-up feature pyramid network that improves low-level information detection. Additionally, the structure of the detection head is improved to minimize the computational cost. The proposed method was trained and evaluated by fine-tuning parameters through experiments and using public datasets PASCAL VOC 07 and MS COCO 2017 datasets. The average precision (AP) metric is used for our quantitative evaluation matrix for detection performance, and our model achieves an average 1.5% accuracy improvement at about 33.85% lower computational cost on each dataset than the conventional method. Finally, the efficiency of the proposed method is verified by comparing the proposed method with the conventional method through an ablation study. [ABSTRACT FROM AUTHOR]

SUMMARY: Sorghum is an important food and feed crop globally; its production is hampered by anthracnose disease caused by the fungal pathogen Colletotrichum sublineola (Cs). Here, we report identification and characterization of ANTHRACNOSE RESISTANCE GENE 2 (ARG2) encoding a nucleotide‐binding leucine‐rich repeat (NLR) protein that confers race‐specific resistance to Cs strains. ARG2 is one of a cluster of several NLR genes initially identified in the sorghum differential line SC328C that is resistant to some Cs strains. This cluster shows structural and copy number variations in different sorghum genotypes. Different sorghum lines carrying independent ARG2 alleles provided the genetic validation for the identity of the ARG2 gene. ARG2 expression is induced by Cs, and chitin induces ARG2 expression in resistant but not in susceptible lines. ARG2‐mediated resistance is accompanied by higher expression of defense and secondary metabolite genes at early stages of infection, and anthocyanin and zeatin metabolisms are upregulated in resistant plants. Interestingly, ARG2 localizes to the plasma membrane when transiently expressed in Nicotiana benthamiana. Importantly, ARG2 plants produced higher shoot dry matter than near‐isogenic lines carrying the susceptible allele suggesting an absence of an ARG2 associated growth trade‐off. Furthermore, ARG2‐mediated resistance is stable at a wide range of temperatures. Our observations open avenues for resistance breeding and for dissecting mechanisms of resistance. Significance Statement: Sorghum is a crop of global importance that is used for food, feed and biofuel. The crop feeds millions of people, especially small holder framers around the world. The productivity of sorghum is constrained by anthracnose diseases caused by the fungus Colletotrichum sublineola. Genetic resistance provides the most sustainable disease control method. We identified and characterized a sorghum anthracnose resistance gene encoding a nucleotide‐binding leucine‐rich repeat protein by exploring natural variation in the crop. Our findings will have significant implications for improvement of disease resistance in sorghum, as well as for future studies in the molecular genetics of pathogen resistance. [ABSTRACT FROM AUTHOR]

Genetic similarity matrices are commonly used to assess population substructure (PS) in genetic studies. Through simulation studies and by the application to whole-genome sequencing (WGS) data, we evaluate the performance of three genetic similarity matrices: the unweighted and weighted Jaccard similarity matrices and the genetic relationship matrix. We describe different scenarios that can create numerical pitfalls and lead to incorrect conclusions in some instances. We consider scenarios in which PS is assessed based on loci that are located across the genome ('globally') and based on loci from a specific genomic region ('locally'). We also compare scenarios in which PS is evaluated based on loci from different minor allele frequency bins: common (>5%), low-frequency (5–0.5%) and rare (<0.5%) single-nucleotide variations (SNVs). Overall, we observe that all approaches provide the best clustering performance when computed based on rare SNVs. The performance of the similarity matrices is very similar for common and low-frequency variants, but for rare variants, the unweighted Jaccard matrix provides preferable clustering features. Based on visual inspection and in terms of standard clustering metrics, its clusters are the densest and the best separated in the principal component analysis of variants with rare SNVs compared with the other methods and different allele frequency cutoffs. In an application, we assessed the role of rare variants on local and global PS, using WGS data from multiethnic Alzheimer's disease data sets and European or East Asian populations from the 1000 Genome Project. [ABSTRACT FROM AUTHOR]

Recently, water scarcity has become a serious social problem caused by global climate change. In agricultural water usage, subsurface irrigation techniques can be an alternative method to save water and improve the productivity and quality of crops. The technique supplies water by burying an irrigation hose 30 cm underground rather than placing it on the ground (topsoil), effectively preventing evaporation loss at the soil surface. In this study, we numerically calculated the pressure drop using a dripper installed inside an underground irrigation hose developed in Korea. The pumping load of the domestic product was evaluated in terms of momentum loss and compared with the most widely used Netafim products. The lower the pressure drop in the dripper, the higher the performance of the irrigation system in terms of stable water supply. Using computational fluid dynamics and experiments, we provide a meaningful evaluation of the domestic product in the irrigation system. [ABSTRACT FROM AUTHOR]

Asthma and chronic obstructive pulmonary disease (COPD) are two distinct diseases that are associated with chronic inflammation. They share common features in terms of their advanced stages and genetic factors. This study aimed to identify novel genes underlying both asthma and COPD using genome-wide association study (GWAS) to differentiate between the two diseases. We performed a GWAS of asthma and COPD in 7828 Koreans from three hospitals. In addition, we investigated genetic correlations. The UK Biobank dataset was used for the replication studies. We found that rs2961757, located near neuromedin U receptor 2 (NMUR2) on chromosome 5, was genome-wide significant ( β Asthma - COPD = 0.44, P-valueAsthma-COPD = 3.41 × 10−8), and significant results were replicated with the UK Biobank data ( β Asthma - COPD = 0.04, P-valueAsthma-COPD = 0.0431). A positive genetic correlation was observed between asthma and COPD (39.8% in the Korean dataset and 49.8% in the UK Biobank dataset). In this study, 40–45% of the genetic effects were common to asthma and COPD. Moreover, NMUR2 increases the risk of asthma development and suppresses COPD development. This indicates that NMUR2 allows for better differentiation of both diseases, which can facilitate tailored medical therapy. [ABSTRACT FROM AUTHOR]

As of June 2022, the GISAID database contains more than 11 million SARS-CoV-2 genomes, including several thousand nucleotide sequences for the most common variants such as delta or omicron. These SARS-CoV-2 strains have been collected from patients around the world since the beginning of the pandemic. We start by assessing the similarity of all pairs of nucleotide sequences using the Jaccard index and principal component analysis. As shown previously in the literature, an unsupervised cluster analysis applied to the SARS-CoV-2 genomes results in clusters of sequences according to certain characteristics such as their strain or their clade. Importantly, we observe that nucleotide sequences of common variants are often outliers in clusters of sequences stemming from variants identified earlier on during the pandemic. Motivated by this finding, we are interested in applying outlier detection to nucleotide sequences. We demonstrate that nucleotide sequences of common variants (such as alpha, delta, or omicron) can be identified solely based on a statistical outlier criterion. We argue that outlier detection might be a useful surveillance tool to identify emerging variants in real time as the pandemic progresses. [ABSTRACT FROM AUTHOR]

As of June 2022, the GISAID database contains more than 11 million SARS-CoV-2 genomes, including several thousand nucleotide sequences for the most common variants such as delta or omicron. These SARS-CoV-2 strains have been collected from patients around the world since the beginning of the pandemic. We start by assessing the similarity of all pairs of nucleotide sequences using the Jaccard index and principal component analysis. As shown previously in the literature, an unsupervised cluster analysis applied to the SARS-CoV-2 genomes results in clusters of sequences according to certain characteristics such as their strain or their clade. Importantly, we observe that nucleotide sequences of common variants are often outliers in clusters of sequences stemming from variants identified earlier on during the pandemic. Motivated by this finding, we are interested in applying outlier detection to nucleotide sequences. We demonstrate that nucleotide sequences of common variants (such as alpha, delta, or omicron) can be identified solely based on a statistical outlier criterion. We argue that outlier detection might be a useful surveillance tool to identify emerging variants in real time as the pandemic progresses. [ABSTRACT FROM AUTHOR]

Algal blooms have been observed worldwide and have had a serious impact on industries that use water resources, which is a problem for people and the environment. For this reason, an algae warning system is used to count the number of cyanobacterial cells and the concentration of chlorophyll-a. Several studies using multispectral or hyperspectral data to estimate chlorophyll concentration have recently been carried out. In the present study, a comparative approach was applied to estimate the concentration of chlorophyll-a at Paldang Dam, South Korea using hyperspectral data. We developed a framework for estimating chlorophyll-a using dimension reduction methods, such as principal component analysis and partial least squares, and various machine learning algorithms. We analyzed hyperspectral data collected during a field survey to locate peaks in the chlorophyll-a spectrum. The framework that used support vector regression achieved the highest R2 of 0.99, a mean square error (MSE) of 1.299 μg/cm3, and showed a small discrepancy between observed and real values relative to other frameworks. These findings suggest that by combining hyperspectral data with dimension reduction and a machine learning algorithm, it is possible to provide an accurate estimation of chlorophyll-a. Using this, chlorophyll-a can be obtained in real time through hyperspectral sensor data input from drones or unmanned aerial vehicles using the learned machine learning algorithm. [ABSTRACT FROM AUTHOR]

Background: Seasonal influenza virus infection causes a range of disease severity, including lower respiratory tract infection with respiratory failure. We evaluated the association of common variants in interferon (IFN) regulatory genes with susceptibility to critical influenza infection in children.Methods: We performed targeted sequencing of 69 influenza-associated candidate genes in 348 children from 24 US centers admitted to the intensive care unit with influenza infection and lacking risk factors for severe influenza infection (PICFlu cohort, 59.4% male). As controls, whole genome sequencing from 675 children with asthma (CAMP cohort, 62.5% male) was compared. We assessed functional relevance using PICFlu whole blood gene expression levels for the gene and calculated IFN gene signature score.Results: Common variants in DDX58, encoding the retinoic acid-inducible gene I (RIG-I) receptor, demonstrated association above or around the Bonferroni-corrected threshold (synonymous variant rs3205166; intronic variant rs4487862). The intronic single-nucleotide polymorphism rs4487862 minor allele was associated with decreased DDX58 expression and IFN signature (P < .05 and P = .0009, respectively) which provided evidence supporting the genetic variants' impact on RIG-I and IFN immunity.Conclusions: We provide evidence associating common gene variants in DDX58 with susceptibility to severe influenza infection in children. RIG-I may be essential for preventing life-threatening influenza-associated disease. [ABSTRACT FROM AUTHOR]

The identification and understanding of gene-environment interactions can provide insights into the pathways and mechanisms underlying complex diseases. However, testing for gene-environment interaction remains a challenge since a.) statistical power is often limited and b.) modeling of environmental effects is nontrivial and such model misspecifications can lead to false positive interaction findings. To address the lack of statistical power, recent methods aim to identify interactions on an aggregated level using, for example, polygenic risk scores. While this strategy can increase the power to detect interactions, identifying contributing genes and pathways is difficult based on these relatively global results. Here, we propose RITSS (Robust Interaction Testing using Sample Splitting), a gene-environment interaction testing framework for quantitative traits that is based on sample splitting and robust test statistics. RITSS can incorporate sets of genetic variants and/or multiple environmental factors. Based on the user's choice of statistical/machine learning approaches, a screening step selects and combines potential interactions into scores with improved interpretability. In the testing step, the application of robust statistics minimizes the susceptibility to main effect misspecifications. Using extensive simulation studies, we demonstrate that RITSS controls the type 1 error rate in a wide range of scenarios, and we show how the screening strategy influences statistical power. In an application to lung function phenotypes and human height in the UK Biobank, RITSS identified highly significant interactions based on subcomponents of genetic risk scores. While the contributing single variant interaction signals are weak, our results indicate interaction patterns that result in strong aggregated effects, providing potential insights into underlying gene-environment interaction mechanisms. Author summary: The understanding of gene-environment interactions provides potential insights into the pathways and mechanisms underlying complex diseases, but they are hard to detect since effect sizes are expected to be small. To facilitate the detection of such interactions in quantitative traits, we propose a robust and flexible approach called RITSS that can incorporate sets of genetic variants and multiple environmental factors. RITSS can utilize any suitable machine/statistical learning approach to screen for interactions and rigorously tests these aggregated signals using sample splitting and robust test statistics. We demonstrate the validity and power of our approach in extensive simulation studies. Furthermore, in an application to lung function and height data in the UK Biobank, RITSS discovers highly significant interactions based on subcomponents of genetic risk scores. [ABSTRACT FROM AUTHOR]

Various flaps are used to reconstruct skin and soft tissue defects of the vulva following resection of malignancies. Whenever possible, reconstruction using local flaps is the standard treatment. Here, we describe vulvar defect reconstruction using keystone flaps. Standard keystone flaps are based on randomly located vascular perforators. However, we designed a keystone flap that includes perforators of three named arteries (the anterior labial artery of the external pudendal artery, cutaneous branches of the obturator artery, and posterior labial artery of the internal pudendal artery) and the pudendal nerve, which accompanies the internal pudendal artery. Four patients with squamous cell carcinoma and extramammary Paget's disease of the vulva underwent radical vulvectomy and keystone flaps including perforators of three arteries. Depending on the morphology of the defects, keystone flaps were used with different designs. For elliptical and unilateral vulvar defects, a standard keystone flap was designed, and for defects on both sides of the vulva, a double opposing keystone flap was used. For oval defects, the omega variant keystone flap was designed, and when the morphology of the defect needed rotation of the flap, a rotational keystone flap was designed. All the patients showed good function and sensation, with an acceptable cosmetic appearance. [ABSTRACT FROM AUTHOR]

Qi-invigorating herbs (QIHs) are a group of herbs that invigorate Qi, the most vital force for maintaining the physiological functions of the human body in traditional medicine. However, the mechanism underlying the Qi-invigorating effects remains unclear. This study aimed to elucidate the unique mechanisms of QIHs based on unique compounds, using a network pharmacology approach. QIHs and their compounds were identified using existing literature and the TCMSP database, respectively. Subsequently, a method was proposed to screen for unique compounds that are common in QIHs but rare in other traditional herbs. Unique compounds' targets were predicted using the TCMSP, BATMAN-TCM, and SwissTargetPrediction databases. Finally, enriched GO and KEGG pathways were obtained using DAVID to uncover the biomolecular functions and mechanisms. Thirteen unique compounds, mainly including amino acids and vitamins that participate in energy metabolism and improve Qi deficiency syndrome, were identified among the eight QIHs. GO and KEGG pathway analyses revealed that these compounds commonly participate in neuroactive ligand–receptor interaction and the metabolism of amino acids, and are related to the components of mitochondria and neuronal cells. Our results appropriately reflect the characteristics of traditional Qi-invigorating effects; therefore, this study facilitates the scientific interpretation of Qi functions and provides evidence regarding the treatment effectiveness of QIHs. [ABSTRACT FROM AUTHOR]

South Korea has a plan to realize a hydrogen economy, and it is essential to establish a main hydrogen pipeline for hydrogen transport. This study develops a cost estimation model applicable to the construction of hydrogen pipelines and conducts an economic analysis to evaluate various scenarios for hydrogen pipeline construction. As a result, the cost of modifying an existing natural gas to a hydrogen pipeline is the lowest, however, there are issues with the safety of the modified hydrogen pipes from natural gas and the necessity of the existing natural gas pipelines. In the case of a short-distance hydrogen pipeline, the cost is about 1.8 times that of the existing natural gas pipeline modification, but it is considered a transitional scenario before the construction of the main hydrogen pipeline nationwide. Lastly, in the case of long-distance main hydrogen pipeline construction, it takes about 3.7 times as much cost as natural gas pipeline modification, however it has the advantage of being the ultimate hydrogen pipeline network. In this study, various hydrogen pipeline establishment scenarios ware compared. These results are expected to be utilized to establish plans for building hydrogen pipelines and to evaluate their economic feasibility. [ABSTRACT FROM AUTHOR]

Background. Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder with a high global incidence. Panax ginseng has been used to treat T2DM in traditional medicine, with previous in vitro, in vivo, and clinical trial studies demonstrating its efficacy. This study aimed to determine the mechanism of P. ginseng in treating T2DM by network pharmacology. Methods. The bioactive compounds of P. ginseng and corresponding targets of P. ginseng-T2DM were retrieved across multiple databases. The protein-protein interaction network was established using the STRING database and topological analysis helped identify the core target. Using the DAVID tool, we performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Finally, we checked the binding of core targets and bioactive compounds using molecular docking. Results. The P. ginseng-T2DM networks mainly contained 22 bioactive compounds and 314 overlapping targets. The five most significant core targets were SRC, STAT3, MAPK1, AKT1, and PIK3R1. There were 244 GO terms and 95 KEGG pathways (adjusted p < 0.01) that were strongly correlated with diabetes-related signaling pathways, such as insulin resistance, the HIF-1 signaling pathway, the PI3K/Akt signaling pathway, the prolactin signaling pathway, the Rap1 signaling pathway, the Ras signaling pathway, the calcium signaling pathway, and the FoxO signaling pathway. Molecular docking results revealed that the top five core targets had a high binding affinity with the bioactive compounds of P. ginseng. Conclusion. The bioactive compounds and targets in P. ginseng ameliorate T2DM by regulating insulin resistance and multiple signaling pathways. [ABSTRACT FROM AUTHOR]

In recent deep-learning-based real-time object detection methods, the trade-off between accuracy and computational cost is an important consideration. Therefore, based on the fully convolutional one-stage detector (FCOS), which is a one-stage object detection method, we propose a light next FCOS (LNFCOS) that achieves an optimal trade-off between computational cost and accuracy. In LNFCOS, the loss of low- and high-level information is minimized by combining the features of different scales through the proposed feature fusion module. Moreover, the light next block (LNblock) is proposed for efficient feature extraction. LNblock performs feature extraction with a low computational cost compared with standard convolutions, through sequential operation on a small amount of spatial and channel information. To define the optimal parameters of LNFCOS suggested through experiments and for a fair comparison, experiments and evaluations were conducted on the publicly available benchmark datasets MSCOCO and PASCAL VOC. Additionally, the average precision (AP) was used as an evaluation index for quantitative evaluation. LNFCOS achieved an optimal trade-off between computational cost and accuracy by achieving a detection accuracy of 79.3 AP and 37.2 AP on the MS COCO and PASCAL VOC datasets, respectively, with 36% lower computational cost than the FCOS. [ABSTRACT FROM AUTHOR]

This article presents a 26–30 GHz gallium nitride (GaN) high electron mobility transistor (HEMT) low-noise amplifier (LNA) for fifth-generation base station applications. In the proposed design, a series inductor-based stability enhancement technique was utilized to improve the reverse isolation and stability performance of the amplifier and to mitigate the effect of the parasitic capacitance of the GaN HEMT device. To validate the concept of the design, a three-stage GaN HEMT LNA was designed and fabricated in a 0.15-um GaN on silicon carbide technology. The demonstrated design achieved a gain of 20.2 dB, a noise figure of 2.4–2.5 dB, an output 1-dB compression point of 17.2 dBm, and an output third-order intercept point of 32.2 dBm. The design also attained stability (μ criterion) up to 7.7 at the operating frequency. The implemented design consumed power of 320 mW with a nominal supply of 10 V. [ABSTRACT FROM AUTHOR]

Background: Abdominal organ injuries are a rarely reported complication when deep acupuncture needling is applied to the abdomen. In order to ascertain the allowable needle insertion range (ANIR) of the abdomen region, we selected acupoint CV12, which is commonly used for treating gastric disease, and ANIR was measured with an ultrasound device. Method: Eighty-five healthy volunteers were recruited, of which 83 cases of ultrasound images were obtained. To investigate the prediction factor of ANIR, we also measured several anthropometric factors. Results: The average ANIR was 25.3 ± 10.2; generally, the ANIRs of females were thicker than those of males; and the liver was observed in 62.7% subjects' ultrasound images. The non-observed group showed thicker ANIR and higher BMI than the liver-observed group. Conclusion: There are reliable variables that make it possible to predict the ANIR. It is advised to refer to anthropometric factors in needling acupoint CV12 to avoid complications with the acupuncture treatment. However, individual differences are not negligible when applying deep needling. Thus, if the risk is not judged before or during the procedure, practitioners could consider the patient's ANIR on CV12 when applying acupuncture by examining the individual anatomical structures using ultrasound and considering internal organ positions to prevent adverse events due to acupuncture. [ABSTRACT FROM AUTHOR]

Summary: Histone lysine methylations (HLMs) are implicated in control of gene expression in different eukaryotes. However, the role of HLMs in regulating desirable crop traits and the enzymes involved in these modifications are poorly understood.We studied the functions of tomato histone H3 lysine methyltransferases SET Domain Group 33 (SDG33) and SDG34 in biotic and abiotic stress responses. SDG33 and SDG34 gene edited mutants were altered in H3K36 and H3K4 methylations, and expression of genes involved in diverse processes and responses to biotic and abiotic stimuli.The double but not the single mutants show resistance to the fungal pathogen Botrytis cinerea. Interestingly, single mutants were tolerant to drought and the double mutant showed superior tolerance and plant growth consistent with independent and additive functions. Mutants maintained higher water status during drought and improved recovery and survival after lapse of drought.Notably, diminution of H3K4 and H3K36 trimethylation and expression of negative regulators in challenged plants contributes to stress tolerance of the mutants. Mutations in SDG33 and SDG34 are likely to remove predisposition to biotic and abiotic stress by disrupting permissive transcriptional context promoting expression of negative regulatory factors. These allows improvement of stress and pathogen tolerance, without growth trade‐offs, through modification of histone epigenetic marks. [ABSTRACT FROM AUTHOR]

Genetic influence on lung functions has been identified in previous studies; however, the relative longitudinal effects of genetic factors and their interactions with smoking on lung function remain unclear. Here, we identified the longitudinal effects of genetic variants on lung function by determining single nucleotide polymorphism (SNP) heritability and genetic correlations, and by analyzing interactions with smoking. Subject-specific means and annual change rates were calculated for eight spirometric measures obtained from 6622 Korean adults aged 40–69 years every two years for 14 years, and their heritabilities were estimated separately. Statistically significant (p < 0.05) heritability for the subject-specific means of all spirometric measures (8~32%) and change rates of forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC; 16%) and post-bronchodilator FEV1/FVC (17%) were detected. Significant genetic correlations of the change rate with the subject-specific mean were observed for FEV1/FVC ( ρ g = 0.64) and post-bronchodilator FEV1/FVC ( ρ g = 0.47). Furthermore, post-bronchodilator FEV1/FVC showed significant heritability of SNP-by-smoking interaction ( h G X S 2 = 0.4) for the annual change rate. The GWAS also detected genome-wide significant SNPs for FEV1 (rs4793538), FEV1/FVC (rs2704589, rs62201158, and rs9391733), and post-bronchodilator FEV1/FVC (rs2445936). We found statistically significant evidence of heritability role on the change in lung function, and this was shared with the effects on cross-sectional measurements. We also found some evidence of interaction with smoking for the change of lung function. [ABSTRACT FROM AUTHOR]

A subsurface drip irrigation system delivers water and nutrients directly to the plant root zone; other conventional nozzles-type or sprinklers-type irrigation are not used, and water-saving can reach 42–78%. In order to achieve this impact effectively, the drip irrigation requires a constant water supply under variations in pressure, which is so-called pressure compensating (PC) performance. The pressure compensating feature can be obtained by physical interaction between water flow and deformable silicone rubber in the PC dripper. In addition, pressure condition to ensure uniform water flow as a tresholding point also should be well designed, but it is generally have relied on the empiricial optimization. Here, we applied computational fluid dynamics to investigate water flow features in terms of flow rate and pressure drop of a conventional PC dripper. To understand the quantitative effects of changes in design parameters, we explored the fluid-structure interaction scheme in the CFD analysis between water flow and silicone rubber deformation. In this study, it is found that the marginal space for the silicone rubber deformation determined the threshold pressure condition; the friction condition of the tortuous channel of the dripper controlled the flow rate. This parametric study gave the logical insight to design new drip emitter with well-controlled and improved performance. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulations of melt films of poly(alkyl methacrylate)s (PAMAs) with methyl, ethyl, and n‐butyl substituents, respectively, have been performed using an all‐atom model to investigate their surface and thin film properties. The applied all‐atom force fields predict the bulk densities of PAMAs in good agreement with experiments. Moreover, predictions of the surface tensions of PMMA, PEMA, and Pn‐BMA melts are in reasonably good agreement with experiments. The density profiles and orientational‐order parameters of chain segments show atomic‐scale characteristics in the air/polymer interfacial region. In the surface region, the backbone segments of PAMAs form a well‐defined layer structure with the chain vectors oriented parallel to the surface, while the ester side‐chains strongly segregate to the surface region and show perpendicular orientation to the surface, with the most pronounced surface segregation noted for Pn‐BMA. Such surface segregations of chain segments make it difficult to apply a simple relationship between the cohesive energy density and the surface tension of polymers, for example, and should be taken into account in relating the surface/thin film characteristics to the bulk properties of polymers in general. [ABSTRACT FROM AUTHOR]