Late Parasitological Failure and Subsequent Isolated Gametocytemia of Uncomplicated Plasmodium falciparum Malaria in a Returned Traveler From Ghana, 2023.

Herein, we report a case of uncomplicated falciparum malaria with late parasitological failure in a 45-year-old businessman returning from Ghana. The patient visited the emergency department with high fever, headache, and dizziness. He traveled without antimalarial chemoprophylaxis. Laboratory tests led to the diagnosis of uncomplicated falciparum malaria with an initial density of 37,669 parasites per µL of blood (p/µL). The patient was treated with intravenous artesunate followed by atovaquone/proguanil. He was discharged with improved condition and decreased parasite density of 887 p/µL. However, at follow-up, parasite density increased to 7,630 p/µL despite the absence of any symptoms. Suspecting treatment failure, the patient was administered intravenous artesunate and doxycycline for seven days and then artemether/lumefantrine for three days. Blood smear was negative for asexual parasitemia after re-treatment but positive for gametocytemia until day 101 from the initial diagnosis. Overall, this case highlights the risk of late parasitological failure in patients with imported uncomplicated falciparum malaria.

Metabolic pathway of tebuconazole by soil fungus Cunninghamella elegans ATCC36112.

Tebuconazole is the most widely used fungicide in agriculture. Due to its long half-life, tebuconazole residues can be found in the environment media such as in soil and water bodies. Here, the metabolic pathway of tebuconazole was studied in Cunninghamella elegans (C. elegans). Approximately 98% of tebuconazole was degraded within 7 days, accompanied by the accumulation of five metabolites. The structures of the metabolites were completely or tentatively identified by gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To identify representative oxidative enzymes that may be involved in the metabolic process, treatment with piperonyl butoxide (PB) and methimazole (MZ) was performed. PB had a strong inhibitory effect on the metabolic reactions, while MZ had a weak inhibitory effect. The results suggest that cytochrome P450 (CYP) and flavin-dependent monooxygenase are involved in the metabolism of tebuconazole. Based on the results, we propose a metabolic pathway for the fungal metabolism of tebuconazole. Data are of interest to gain insight into the toxicological effects of tebuconazole and for tebuconazole bioremediation.

Changes in anxiety and depression levels and meat intake following recognition of low genetic risk for high body mass index, triglycerides, and lipoproteins: A randomized controlled trial.

BACKGROUND: Psychological status affects dietary intake, and recognizing genetic information can lead to behavior changes by influencing psychological factors such as anxiety or depression. OBJECTIVES: In this study, we examined the effects of disclosing genetic information on anxiety or depression levels and the association between these psychological factors and dietary intake. METHODS: A total of 100 healthy adults were randomly assigned to an intervention group (n = 65) informed about their genetic test results regarding body mass index and lipid profiles (triglyceride and cholesterol concentrations) and a not-informed control group (CON, n = 35). Based on polygenic risk scores, participants in the intervention group were subclassified into an intervention-low risk (ILR, n = 32) and an intervention-high risk (IHR, n = 33) group. Nutrient and food intakes were assessed via a 3-day dietary record at baseline and at 3 and 6 months. Depression and anxiety levels were measured using PHQ-9 and GAD-7 questionnaires, and the relative levels of blood metabolites were measure using GC-MS/MS analysis. RESULTS: Noticeable changes in dietary intake as well as psychological factors were observed in male subjects, with those perceiving their genetic risks as low (ILR) showing a significant increase in protein intake at 3 months compared to baseline (ILR: 3.9 ± 1.4, p<0.05). Meat intake also increased significantly in males in the ILR group at 3 months, but not in the IHR and CON groups (ILR: 49.4 ± 30.8, IHR: -52.2 ± 25.4, CON: -5.3 ± 30.3 g/d). ILR group showed a significant decrease in anxiety levels at 3 months, and their anxiety scores showed a negative association with meat intake (standardized ß = -0.321, p<0.05). The meat intake at 3 months was associated with the relative levels of arginine and ornithine (standardized ß = 0.452, p<0.05 and standardized ß = 0.474, p<0.05, respectively). CONCLUSIONS: Taken together, anxiety levels were decreased in male subjects who perceived their genetic risk to be low, and the decrease in anxiety levels was associated with an increase in meat intake. This suggests that recognizing genetic information may affect psychological factors and dietary intake.

Prognosis of Patients with Chronic Hepatitis C Genotype 1b Infection Treated Using Daclatasvir/Asunaprevir after Sustained Virologic Response: A 6-Year Multicenter Prospective Observational Study.

Aim and Objectives: Direct-acting antiviral (DAA) therapy can cure chronic hepatitis C (CHC), and daclatasvir (DCV)/asunaprevir (ASV) was the first interferon-free DAA therapy introduced in Korea. Patients who achieve sustained virologic response (SVR) after DAA treatment are expected to have good prognoses. Therefore, in this study, we aimed to investigate the prognosis of these patients. Materials and Methods: This multicenter prospective observational study included patients with CHC who achieved SVR after DCV/ASV treatment. The primary endpoint was hepatocellular carcinoma (HCC) occurrence, which was reviewed annually. Results: We included 302 patients (median follow-up duration: 38 [16.5-60.0] months; median age: 58 [49-67] years) in the study. Cirrhosis was observed in 103 patients (34.1%), and the median Child-Pugh score was 5.0. HCC occurred in 16 patients (5.3%) within six years post-SVR; these patients were older and had higher cirrhosis prevalence, alpha-fetoprotein levels, and fibrosis-4 index scores than did those without HCC development. Cox proportional hazards analysis revealed that age > 71 years (p = 0.005) and cirrhosis (p = 0.035) were significant risk factors for HCC occurrence. Conclusions: Although the prognoses of patients who achieved SVR with DCV/ASV therapy were generally good, the risk for HCC was present, especially in older patients and in those with cirrhosis. Hence, early treatment at younger ages and regular follow-up surveillance after achieving SVR are warranted.

Metabolism of an insecticide fipronil by soil fungus Cunninghamella elegans ATCC36112.

In this study, the metabolic pathway of the phenylpyrazole insecticide fipronil in Cunninghamella elegans (C. elegans) was investigated. Approximately 92% of fipronil was removed within 5 days, and seven metabolites were accumulated simultaneously. The structures of the metabolites were completely or tentatively identified by GC-MS and 1H, 13C NMR. To determine the oxidative enzymes involved in metabolism, piperonyl butoxide (PB) and methimazole (MZ) were used, and the kinetic responses of fipronil and its metabolites were determined. PB strongly inhibited fipronil metabolism, while MZ weakly inhibited its metabolism. The results suggest that cytochrome P450 (CYP) and flavin-dependent monooxygenase (FMO) may participate in fipronil metabolism. Integrated metabolic pathways can be inferred from the control and inhibitor experiments. Several novel products from the fungal transformation of fipronil were identified, and similarities between C. elegans transformation and mammalian metabolism of fipronil were compared. Therefore, these results will help to gain insight into the fungal degradation of fipronil and potential applications in fipronil bioremediation. At present, microbial degradation of fipronil is the most promising approach and maintains environmental sustainability. In addition, the ability of C. elegans to mimic mammalian metabolism will assist in illustrating the metabolic fate of fipronil in mammalian hepatocytes and assess its toxicity and potential adverse effects.

Antibiotic prescription patterns during last days of hospitalized patients with advanced cancer: the role of palliative care consultation.

OBJECTIVES: Issues regarding antibiotic use in end-of-life patients with advanced cancer present a challenging ethical dilemma in academic referral centres. This study aimed to investigate the role of palliative care consultation on antibiotic prescription patterns among hospitalized patients with advanced cancer during their last days of life. METHODS: This retrospective cohort study included adult patients with metastatic solid cancer admitted to a tertiary referral hospital for at least 4 days and subsequently died and who were given antibiotics 4 days before death between January 2018 and December 2021. Patients were divided into palliative care consultation (PC) and non-consultation (non-PC) groups. The outcomes were the proportion of patients who received antibiotic combination treatment, antibiotic escalation and antibiotic de-escalation within 3 days of death. Propensity score analysis with the inverse probability of the treatment weighting method was used to compare the outcomes. RESULTS: Among the 1177 patients enrolled, 476 (40.4%) received palliative care consultation and 701 (59.6%) did not. The PC group received considerably less antibiotic combination treatment (49.0% versus 61.1%, adjusted OR: 0.69, 95% CI: 0.53-0.90, P = 0.006) and antibiotic escalation (15.8% versus 34.8%, adjusted OR: 0.41, 95% CI: 0.30-0.57, P < 0.001) than the non-PC group. Additionally, the PC group reported significantly higher antibiotic de-escalation (30.7% versus 17.4%, adjusted OR: 1.74, 95% CI: 1.28-2.36, P < 0.001). CONCLUSION: Receiving palliative care consultation may minimize aggressive antibiotic prescription patterns in the last days of patients with advanced cancer in an academic referral centre setting.

Biodegradation and metabolic pathway of quinalphos by Cunninghamella elegans ATCC36112.

Quinalphos is a long-term, wide-spectrum organophosphate insecticide with residual problems in the natural environment. Cunninghamella elegans (C. elegans) is a member of Mucoromycotina. Since the degradation products of its exogenous compounds are similar to those of mammals, it is often used to simulate the metabolism pathways of mammals. In this study, the detailed metabolic pathways of quinalphos were investigated with C. elegans. Quinalphos was degraded by 92% in 7 days, while ten metabolites were produced. The metabolites were analyzed and identified by GC-MS. To determine the responsible enzymes in quinalphos metabolism, piperonyl butoxide (PB) and methimazole included in the culture flasks, and the kinetic responses of quinalphos and its metabolites by C. elegans were measured. Results indirectly demonstrated that cytochrome P450 monooxygenases were involved in the metabolism of quinalphos, but that methimazole inhibited the metabolism less efficiently. Comprehensive metabolic pathways can be deduced from the detailed analysis of metabolite profiles in control and inhibitor assays.

Molecular mechanisms of mitochondrial DNA release and activation of the cGAS-STING pathway.

In addition to constituting the genetic material of an organism, DNA is a tracer for the recognition of foreign pathogens and a trigger of the innate immune system. cGAS functions as a sensor of double-stranded DNA fragments and initiates an immune response via the adaptor protein STING. The cGAS-STING pathway not only defends cells against various DNA-containing pathogens but also modulates many pathological processes caused by the immune response to the ectopic localization of self-DNA, such as cytosolic mitochondrial DNA (mtDNA) and extranuclear chromatin. In addition, macrophages can cause inflammation by forming a class of protein complexes called inflammasomes, and the activation of the NLRP3 inflammasome requires the release of oxidized mtDNA. In innate immunity related to inflammasomes, mtDNA release is mediated by macropores that are formed on the outer membrane of mitochondria via VDAC oligomerization. These macropores are specifically formed in response to mitochondrial stress and tissue damage, and the inhibition of VDAC oligomerization mitigates this inflammatory response. The rapidly expanding area of research on the mechanisms by which mtDNA is released and triggers inflammation has revealed new treatment strategies not only for inflammation but also, surprisingly, for neurodegenerative diseases such as amyotrophic lateral sclerosis.

MELD-GRAIL-Na Is a Better Predictor of Mortality Than MELD in Korean Patients with Cirrhosis.

Background and Objectives: The Child-Pugh (CP) score and Model for End-Stage Liver Disease (MELD) are classical systems for predicting mortality in patients with liver cirrhosis (LC). The MELD-GFR assessment in liver disease-sodium (MELD-GRAIL-Na) was designed to better reflect renal function and, therefore, provide better mortality predictions. This study aimed to compare the prediction accuracy of MELD-GRAIL-Na compared to CP and MELD in predicting short-term (1- and 3-month) mortality in Korean patients. Materials and Methods: Medical records of patients with LC admitted to the Konkuk University Hospital from 2015 to 2020 were retrospectively reviewed. Predictive values of the CP, MELD, and MELD-GRAIL-Na for 1-month and 3-month mortality were calculated using the area under the receiver operating curve (AUROC) and were compared using DeLong's test. Results: In total, 1249 patients were enrolled; 102 died within 1 month, and 146 within 3 months. AUROCs of CP, MELD, and MELD-GRAIL-Na were 0.831, 0.847, and 0.857 for 1-month mortality and 0.837, 0.827, and 0.835 for 3-month mortality, respectively, indicating no statistical significance. For patients with CP classes B and C, AUROCs of CP, MELD, and MELD-GRAIL-Na were 0.782, 0.809, and 0.825 for 1-month mortality and 0.775, 0.769, and 0.786 for 3-month mortality, respectively. There was a significant difference between CP and MELD-GRAIL-Na in predicting 1-month mortality (p = 0.0428) and between MELD and MELD-GRAIL-Na in predicting 1-month (p = 0.0493) and 3-month mortality (p = 0.0225). Conclusions: Compared to CP and MELD, MELD-GRAIL-Na was found to be a better and more useful system for evaluating short-term (1- and 3-month) mortality in Korean patients with cirrhosis, especially those with advanced cirrhosis (CP class B and C).

Potential exposure and risk assessment of agricultural workers to the insecticide chlorantraniliprole in rice paddies.

BACKGROUND: Exposure of agricultural workers in rice paddies to the insecticide chlorantraniliprole and its subsequent potential health risks were investigated during two scenarios (mixing/loading and hand-held spraying). The exposure factors, such as the outer dosimeter, inner dosimeter, gauze, and nitrile gloves, were calculated using whole-body dosimetry to measure dermal exposure. The inhalation exposure was determined using a fiberglass filter which is set with an Institute of Occupational Medicine (IOM) sampler. A recovery test was performed to evaluate the accuracy of the analytical method. RESULTS: The exposure amounts of various matrices were calculated from extraction volume and concentration of the target compound. The dermal exposure to chlorantraniliprole was 0.6 mg [0.001% of the total active ingredient (a.i.)] for mixing and loading, and 28.6 mg (0.066% of the total a.i.) for application. The inhalation exposure to chlorantraniliprole was 7.2 µg (1.3%, 1.2 × 10-5 % of the total applied a.i.) for mixing and loading, and 1.9 µg (0.006%, 4.4 × 10-6 % of the total applied a.i.) for application. The most exposed part of the body was the hand (90.4%) during mixing and loading, whereas the primary sites during application were the thighs (32.8%) and shins (22.6%). For mixing and loading, the amount of actual dermal exposure was 5.5 µg day-1 and that of actual inhalation exposure was 21.9 µg day-1 . By contrast, in the application, the amounts of actual dermal and actual inhalation exposures were 34 178.7 and 5.9 µg day-1 , respectively. CONCLUSIONS: The risk assessment results demonstrated that the risk of chlorantraniliprole exposure in rice paddies was low during application than during mixing and loading. © 2022 Society of Chemical Industry.

The impact of palliative care consultation on reducing antibiotic overuse in hospitalized patients with terminal cancer at the end of life: a propensity score-weighting study.

OBJECTIVES: A substantial number of hospitalized patients with terminal cancer at the end-of-life phase receive antibiotics, even with imminent death. We evaluated the impact of palliative care consultation on antibiotic use in hospitalized patients with terminal cancer during the end-of-life phase. METHODS: We identified adult patients with metastatic solid cancer who died at a tertiary medical centre in Seoul, Republic of Korea, following at least 4 days of hospitalization (January 2018-December 2020). Patients were divided into palliative and non-palliative care consultation groups. Propensity score-weighted, multivariable logistic regression analysis was used to compare the proportion of patients receiving antibiotics within 3 days before death between the two groups. RESULTS: Among 1143 patients analysed, 940 (82.2%) received antibiotics within 3 days before death. The proportion of patients receiving antibiotics was significantly lower (propensity score-weighted P < 0.001) in the palliative care consultation group (344/468; 73.5%) than in the non-palliative care consultation group (596/675; 88.3%). The decrease in the proportion of patients receiving antibiotics in the palliative care consultation group was significant for a carbapenem (42.4% versus 22.4%; P < 0.001), a glycopeptide (23.3% versus 11.1%; P < 0.001) and a quinolone (30.5% versus 19.4%; P = 0.012). In the multivariable logistic regression analysis, receiving palliative care consultation (adjusted OR 0.46, 95% CI 0.33-0.65; P < 0.001) was independently associated with reduced antibiotic use during the end-of-life phase. CONCLUSIONS: Palliative care consultation may reduce aggressive antibiotic use in hospitalized patients with terminal cancer during the end-of-life phase.

Impact of Pt grain size on ferroelectric properties of zirconium hafnium oxide by chemical solution deposition.

The effects of the grain size of Pt bottom electrodes on the ferroelectricity of hafnium zirconium oxide (HZO) were studied in terms of the orthorhombic phase transformation. HZO thin films were deposited by chemical solution deposition on the Pt bottom electrodes with various grain sizes which had been deposited by direct current sputtering. All the samples were crystallized by rapid thermal annealing at 700 °C to allow a phase transformation. The crystallographic phases were determined by grazing incidence X-ray diffraction, which showed that the bottom electrode with smaller Pt grains resulted in a larger orthorhombic phase composition in the HZO film. As a result, capacitors with smaller Pt grains for the bottom electrode showed greater ferroelectric polarization. The smaller grains produced larger in-plane stress which led to more orthorhombic phase transformation and higher ferroelectric polarization.

Simple and rapid method for 336 multiresidual pesticide analysis in saliva, determination of their chemical stabilities, and biomonitoring of farmers.

Simultaneous multiresidual pesticide analysis of saliva samples was performed using scaled-down QuEChERS extraction with LC-MS/MS and GC-MS/MS. The optimum extraction procedure using acidified acetonitrile was applicable to 336 pesticides (287 for LC-MS/MS and 49 for GC-MS/MS). To determine pesticide multiresidues in saliva, 100 µL of the sample was extracted with 200 µL of 0.1% formic acid in acetonitrile, and the initial extract was partitioned with 40 mg of MgSO4 and 10 mg of NaCl. The organic supernatants (120 µL) were then mixed with acetonitrile (30 µL) for matrix-matching (4:1, v/v), and the final extract solution was injected into the LC-MS/MS (4 µL) and GC-MS/MS (2 µL) systems. The established analytical method showed a good LOQs between 5 and 25 ng/mL with reliable accuracy/precision values and recovery results (50-140%) for the target pesticides. Under the two different storage conditions, most of the analytes did not undergo chemical changes in the saliva samples, whereas some pesticides were more stable in freeze-thaw processes than those left at room temperature. Biomonitoring of farmers (ten mixers and ten sprayers) was successfully applied using the validated method, and two carbamates (fenobucarb and propamocarb) were determined at trace concentrations (12.5-675.0 ng/mL from 11 positively detected samples).

Computational Modeling and Imaging of the Intracellular Oxygen Gradient.

Computational modeling can provide a mechanistic and quantitative framework for describing intracellular spatial heterogeneity of solutes such as oxygen partial pressure (pO2). This study develops and evaluates a finite-element model of oxygen-consuming mitochondrial bioenergetics using the COMSOL Multiphysics program. The model derives steady-state oxygen (O2) distributions from Fickian diffusion and Michaelis-Menten consumption kinetics in the mitochondria and cytoplasm. Intrinsic model parameters such as diffusivity and maximum consumption rate were estimated from previously published values for isolated and intact mitochondria. The model was compared with experimental data collected for the intracellular and mitochondrial pO2 levels in human cervical cancer cells (HeLa) in different respiratory states and under different levels of imposed pO2. Experimental pO2 gradients were measured using lifetime imaging of a Förster resonance energy transfer (FRET)-based O2 sensor, Myoglobin-mCherry, which offers in situ real-time and noninvasive measurements of subcellular pO2 in living cells. On the basis of these results, the model qualitatively predicted (1) the integrated experimental data from mitochondria under diverse experimental conditions, and (2) the impact of changes in one or more mitochondrial processes on overall bioenergetics.

High Initial Coulombic Efficiency of SiO Enabled by Controlling SiO2 Matrix Crystallization.

SiO is a promising anode material for practical Li-ion batteries because it can achieve a much higher capacity than graphite and a better capacity retention than Si. However, SiO suffers from poor initial Coulombic efficiency (ICE). Here, we report on a fundamentally different approach to increase the low ICE of SiO while achieving high capacity and long-term cycle stability compared to previous approaches such as electrochemical/chemical pre-lithiation processes. To enhance the ICE, the long-range/short-range orders of amorphous SiO2 in SiO are increased by the chemical reaction of a small amount of LiOH·H2O even at a much lower temperature (900 °C) than the reported. The increased crystallization of SiO2 substantially reduces the irreversible electrochemical reaction of SiO. As a result, the Li-added SiO shows substantially increased ICE, ∼82.7%, which is one of the highest values. Furthermore, we demonstrate that controlling the crystallization of SiO can enable us to achieve high ICE, high reversible capacity, and superior capacity retention (∼100% at 1C rate for 100 cycles) in SiO simultaneously. The understanding and findings will pave the way to design high-capacity SiO with high ICE and long-term stability for practical high energy density Li batteries.

Occupational exposure and risk assessment for agricultural workers of thiamethoxam in vineyards.

Dermal & inhalation exposure was examined and according to these results, risk assessment of agricultural workers to thiamethoxam was performed during pesticide mixing/loading and hand-held sprayer application (11 replicates, each of about 1000 L of spray suspension) in vineyards. For the whole body dosimetry (WBD), clothing (Outer and inner), gauze, and nitrile gloves were analyzed to determine dermal exposure using whole-body dosimetry exposure protocol. The inhalation exposure was measured using a glass fiber filter with an IOM sampler. Analytical method validation of exposure matrices was evaluated including the field recovery and breakthrough test. The dermal exposure amount during mixing/loading was 0.163 mg (0.0004% of the total mixed/loaded active ingredient [a.i.]), whereas there was no inhalation exposure. The gloves (0.154 mg, 94.5%) were the most exposed body parts followed by the chest and stomach (0.009 mg, 5.5%). During application, the dermal and inhalation exposure amounts were 32.3 mg (0.07% of the total applied a.i.) and 10.8 µg (2.4 × 10-6% of the total applied a.i), respectively. The shin (35.1%) had the highest exposure to pesticides, followed by the chest & stomach (15.6%) and pelvis (12.6%). In case of mixing/loading, the amounts of actual dermal exposure (ADE) and actual inhalation exposure (AIE) were 0.0 and 0.0 µg/day, while those of ADE and AIE were 4707.6 and 15.8 µg/day for application. In risk assessment of the two different scenarios, the risk index was much lower than 1 (mixing/loading:0.000, application:0.014), indicating that vineyard workers are at low risk of thiamethoxam exposure. To determine the validity of the risk assessment using WBD method, the urinary metabolite was analyzed. Comparison of biomonitoring data and WBD exposure data show a reliable correlation (r = 0.885, p = 0.0003), suggesting that these are suitable methods to estimate exposure.

Effectiveness of antimicrobial stewardship programmes based on rapid antibiotic susceptibility testing of haematological patients having high-risk factors for bacteraemia-related mortality: a post-hoc analysis of a randomised controlled trial.

A randomised controlled trial showed that rapid phenotypic antibiotic susceptibility testing (AST) with antimicrobial stewardship programme (ASP) increases the proportion of haematological patients with bacteraemia receiving optimal targeted therapy within 72 h of blood culture collection. This post-hoc analysis aimed to evaluate the effects of rapid phenotypic AST intervention in haematological patients at high risk of a poor outcome from bacteraemia. Haematological patients with bacteraemia (n = 116) were assigned randomly to a conventional AST group or a rapid AST group. The two outcome measures were the proportion of patients receiving optimal targeted therapy at 72 h post blood culture collection and the time to optimal targeted therapy; subgroup analysis was conducted based on baseline demographics (age, sex) and prognostic (Charlson comorbidity index, haematological treatment intensity, Pitt bacteraemia score, appropriateness of empirical antibiotic therapy and multidrug-resistant organism) indicators. The interaction effect between the intervention and subgroup factors was examined using regression model analysis. Age, sex, Charlson comorbidity index, haematological treatment intensity, Pitt bacteraemia score and appropriateness of empirical antibiotic therapy had no significant interaction effects on the proportion of patients receiving optimal targeted therapy (P = 0.129-0.826). However, infection by a multidrug-resistant organism did have a significant interaction effect (P = 0.042). Regarding time to optimal targeted therapy, there were no significant interaction effects between the intervention and subgroup factors (P = 0.156-0.848). In conclusion, rapid phenotypic AST with ASP intervention may accelerate early optimal targeted antimicrobial treatment of haematological patients, even those in high-risk subgroups with bacteraemia.

Synergistic improvement of sensing performance in ferroelectric transistor gas sensors using remnant polarization.

Gaseous pollutants, including nitrogen oxides, pose a severe threat to ecosystems and human health; therefore, developing reliable gas-sensing systems to detect them is becoming increasingly important. Among the various options, metal-oxide-based gas sensors have attracted attention due to their capability for real-time monitoring and large response. In particular, in the field of materials science, there has been extensive research into controlling the morphological properties of metal oxides. However, these approaches have limitations in terms of controlling the response, sensitivity, and selectivity after the sensing material is deposited. In this study, we propose a novel method to improve the gas-sensing performance by utilizing the remnant polarization of ferroelectric thin-film transistor (FeTFT) gas sensors. The proposed FeTFT gas sensor has IGZO and HZO as the conducting channel and ferroelectric layer, respectively. It is demonstrated that the response and sensitivity of FeTFT gas sensors can be modulated by engineering the polarization of the ferroelectric layer. The amount of reaction sites in IGZO, including electrons and oxygen vacancy-induced negatively charged oxygen, is changed depending on upward and downward polarization. The results of this study provide an essential foundation for further development of gas sensors with tunable sensing properties.

Development of a quantitative screening method for pesticide multiresidues in orange, chili pepper, and brown rice using gas chromatography-quadrupole time of flight mass spectrometry with dopant-assisted atmospheric pressure chemical ionization.

A rapid screening method for the quantitative analysis of pesticide multiresidues using a high-resolution accurate mass (HRAM) quadrupole time-of-flight (Q-TOF) with a dopant-assisted gas chromatography-atmospheric pressure chemical ionization (GC-APCI) technique were developed. For convenient and constant supply of APCI dopant, a large-volume dopant bottle with a bypass valve was newly designed, and the developed method was tested with 415 pesticide mixtures for representative produce (orange, chili pepper, and brown rice). Methanol-enriched nitrogen gas was used to produce protonated molecular [M + H]+ ions, and fragment ions were produced by broad-band collision-induced dissociation mode. Twenty representative pesticides were selected and validated for analytical performance. The methanol dopant-assisted GC-APCI-Q-TOF technique is very promising for target and non-target screening and sensitive quantification for hundreds of pesticides in a single run.

Interface-Stabilized Layered Lithium Ni-Rich Oxide Cathode via Surface Functionalization with Titanium Silicate.

Nickel-rich lithium metal oxide cathode materials have recently be en highlighted as next-generation cathodes for lithium-ion batteries. Nevertheless, their relatively high surface reactivity must be controlled, as fading of the cycling retention occurs rapidly in the cells. This paper proposes functionalized nickel-rich lithium metal oxide cathode materials by a multipurpose nanosized inorganic material-titanium silicon oxide-via a simple thermal treatment process. We examined the topologies of the nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathodes with scanning electron microscopy and quantitatively analyzed their improved mechanical properties using microindentation. The cell containing nickel-rich lithium metal oxide cathodes suffered from poor cycling behavior as the electrolytes persistently decomposed; however, this behavior was effectively inhibited in the cell by nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathodes. Further ex situ analyses indicated that the particle hardness of the nano-titanium silicate-functionalized nickel-rich lithium metal oxide cathode materials was maintained, and decomposition of the electrolyte by the dissolution of transition metals was thoroughly inhibited even after 100 cycles. Based on these results, we concluded that the use of nano-titanium silicate as a coating material for nickel-rich lithium metal oxide cathode materials is an effective way to enhance the cycling performance of lithium-ion batteries.