Operando electron microscopy investigation of polar domain dynamics in twisted van der Waals homobilayers.

Conventional antiferroelectric materials with atomic-scale anti-aligned dipoles undergo a transition to a ferroelectric (FE) phase under strong electric fields. The moiré superlattice formed in the twisted stacks of van der Waals crystals exhibits polar domains alternating in moiré length with anti-aligned dipoles. In this moiré domain antiferroelectic (MDAF) arrangement, the distribution of electric dipoles is distinguished from that of two-dimensional FEs, suggesting dissimilar domain dynamics. Here we performed an operando transmission electron microscopy investigation on twisted bilayer WSe2 to observe the polar domain dynamics in real time. We find that the topological protection, provided by the domain wall network, prevents the MDAF-to-FE transition. As one decreases the twist angle, however, this transition occurs as the domain wall network disappears. Exploiting stroboscopic operando transmission electron microscopy on the FE phase, we measure a maximum domain wall velocity of 300 µm s-1. Domain wall pinnings by various disorders limit the domain wall velocity and cause Barkhausen noises in the polarization hysteresis loop. Atomic-scale analysis of the pinning disorders provides structural insight on how to improve the switching speed of van der Waals FEs.

Initial updosing phase of oral immunotherapy improves quality of life and psychological burden in parents of children with food allergy.

Background: Oral immunotherapy (OIT) can impose psychological burdens on patients and their parents due to the necessary preparations and repeated adverse reactions. Objective: To investigate changes in quality of life (QoL) and psychological burden in parents of children receiving OIT for food allergy (FA). Methods: Children aged 3-13 years with FA were enrolled. Parents were asked to fill out the Korean versions of the Food Allergy Quality of Life-Parental Burden (FAQL-PB), the Korean versions of the Food Allergy Quality of Life-Parental Form (K-FAQLQ-PF), the Korean versions of the Beck Anxiety Inventory (K-BAI), and the Korean version of the Patient Health Questionnaire-9 (PHQ-9) for depression before OIT (T1), after 2 months of updosing (T2), and after the end of the updosing phase (T3). Results: A total of 111 parents were enrolled. The total FAQL-PB scores were decreased at T2 and T3 compared with those at T1 (all p < 0.001). Greater improvement in the total FAQL-PB score at T2 was noted in parents with a higher parental burden (FAQL-PB score ≥ 74 points) at baseline than in those with a lower parental burden (p = 0.001). Among the K-FAQLQ-PF domains, "food anxiety" scores were decreased at T2 and T3 compared with those at T1 (p = 0.049 and p = 0.030, respectively), whereas there was no change in "social and dietary limitation" and "emotional impact" scores between T1 and T2 and between T1 and T3. However, no differences were observed in K-BAI and PHQ-9 scores between T1 and T2 and between T1 and T3. Conclusion: Our results suggest that OIT improves parental burden and QoL in parents of children with FA.

MicroRNA-135b-5p Is a Pathologic Biomarker in the Endothelial Cells of Arteriovenous Malformations.

Arteriovenous malformations (AVMs) are congenital vascular anomalies with a poor prognosis. AVMs are considered intractable diseases, as there is no established approach for early diagnosis and treatment. Therefore, this study aimed to provide new evidence by analyzing microRNAs (miRNAs) associated with AVM. We present fundamental evidence for the early diagnosis and treatment of AVM by analyzing miRNAs in the endothelial cells of AVMs. This study performed sequencing and validation of miRNAs in endothelial cells from normal and AVM tissues. Five upregulated and two downregulated miRNAs were subsequently analyzed under hypoxia and vascular endothelial growth factor (VEGF) treatment by one-way analysis of variance (ANOVA). Under hypoxic conditions, miR-135b-5p was significantly upregulated in the AVM compared to that under normal conditions, corresponding to increased endothelial activity (p-value = 0.0238). VEGF treatment showed no significant increase in miR-135b-5p under normal conditions, however, a surge in AVM was observed. Under both hypoxia and VEGF treatment, comparison indicated a downregulation of miR-135b-5p in AVM. Therefore, miR-135b-5p was assumed to affect the pathophysiological process of AVM and might play a vital role as a potential biomarker of AVMs for application related to diagnosis and treatment.

Three-dimensional culture conditioned bone marrow MSC secretome accelerates wound healing in a burn injury mouse model.

Mesenchymal stem cell (MSC)-based therapy has emerged as a promising regenerative therapeutic approach for wound healing. To determine the effects of cultured MSCs as a 2D monolayer (2D-MSCs) and 3D spheroids (3D-MSCs) on their secretomes, and to examine the effect of 3D-MSC secretomes on endothelial cells (ECs) and MSCs in a burn injury mouse model. MSCs were cultured as 2D monolayers (2D-MSCs) and 3D spheroids (3D-MSCs) and their cellular characteristics were evaluated by western blotting. 2D-MSC and 3D-MSC secretomes (condition medium: CM) were analyzed using an angiogenic array. The activation of ECs by 2D-MSC and 3D-MSC CMs was examined in cellular proliferation, migration, and tube formation assays. The wound healing effects of 2D-MSCs and 3D-MSCs were determined in vivo using a burn injury mouse model. 3D culture conditions altered the markers of components that regulate cell survival, cytoskeletal, adhesion, and proliferation. Interleukin-6 (IL-6), vascular endothelial growth factor A (VEGFA), IL-8, and chemokine (CXC motif) ligand 1 (CXCL1) were present at high levels in the CM of 3D-MSCs compared with 2D-MCs. 3D-MSC-CMs promoted the proliferation, migration, and tube formation of ECs. Furthermore, 3D-MSC treatment enhanced wound healing in a burn injury mouse model. 3D culture improves proangiogenic factors in the MSC secretome and 3D-MSCs represent a new cell-based treatment strategy for wound healing.

Influence of Transforming Growth Factors beta 1 and beta 3 in the Scar Formation Process.

BACKGROUND: Transforming growth factor-beta (TGF-ß) plays an instrumental role in forming scars and keloids. TGF-ß isoforms exhibit differential expression, indicating distinct wound healing and scar formation functions. However, the role of TGF-ß1 and TGF-ß3 in wound healing and scar formation remains unclear. This study aimed to compare the specific roles of TGF-ß1 and TGF-ß3 in wound healing and scar formation by biomolecular analysis. MATERIALS AND METHODS: The study was conducted by cell isolation and culture cells from a total of 20 human samples. Normal human fibroblasts (NHF) were isolated from normal human samples and myofibroblasts from the different scar types, namely hypertrophic (HT) and keloid (K) scars. NHF and cells from the HT, and K scar, each of which were divided into 3 sample groups: the untreated control, TGF-ß1 (10 µg/mL)-treated group, and TGF-ß3 (10 µg/mL)-treated group. The results of confocal microscopy and fluorescence-activated cell sorting experiments were compared. RESULTS: Both the HT and K groups had higher α-smooth muscle actin (α-SMA) expression than the NHF group in the untreated control group. In comparison with the untreated group, NHFs showed a significant increase in α-SMA expression in the TGF-ß1-treated group. HT showed a high α-SMA level, which was statistically significant compared with the normal fibroblasts. In the TGF-ß3-treated group, α-SMA expression was slightly increased in NHF as compared with the untreated group. TGF-ß3 treated HT exhibited a greater reduction in α-SMA expression than in the TGF-ß1 treated HT. K, on the other hand, had only a minimal effect on the treatment of TGF-ß1 and TGF-ß3. CONCLUSIONS: The findings suggest that TGF-ß3 may play a regulatory role in the wound repair process, which could be useful in the development of scar-reducing therapies for patients with scar-related cosmetic concerns.

Infection-Induced Rhabdomyolysis in a Pregnant Woman with Undiagnosed Myotonic Dystrophy: A Case Report.

A 34-year-old nulliparous gravid female presented with acute bilateral pyelonephritis at 29 + 5 weeks gestation. The patient was relatively well until two weeks ago when a slight increase in amniotic fluid was noted. Further investigation revealed myoglobinuria and significantly elevated levels of creatine phosphokinase. The patient was subsequently diagnosed with rhabdomyolysis. Twelve hours after admission, the patient noted reduced fetal movements. A non-stress test revealed fetal bradycardia and non-reassuring variability in fetal heart rate. An emergency cesarean section was performed, and a "floppy" female child was delivered. Genetic testing revealed congenital myotonic dystrophy, and the mother was also diagnosed with myotonic dystrophy. Rhabdomyolysis has a very low incidence in pregnancy. Herein, we report a rare case of myotonic dystrophy with rhabdomyolysis in a gravid female with no history of myotonic dystrophy. Acute pyelonephritis is a causative agent of rhabdomyolysis that results in preterm birth.

Perinatal Outcomes and Neurodevelopment 1 Year after Birth in Discordant Twins According to Chorionicity.

Background and Objectives: This study aimed to compare maternal complications, perinatal outcomes, and neurodevelopment 1 year after the birth between concordant and discordant twins in monochorionic and dichorionic twins. Materials and Methods: This retrospective study included twin pregnancies delivered between 24 + 1 and 38 + 2 weeks of gestation between January 2011 and September 2019. Chorionicity was confirmed by ultrasonography and was categorized into monochorionic and dichorionic. Each was then divided into two groups (concordant and discordant) according to birth weight discordancy. Maternal complications and neonatal outcomes, including neurodevelopmental delays, were compared between the two groups. Results: A total of 298 pairs of twin pregnancies were enrolled, of which 58 (19.26%) women were pregnant with monochorionic diamniotic twins and 240 (80.54%) with dichorionic diamniotic twins. In both monochorionic and dichorionic twins, the discordant twins had a greater incidence of emergency deliveries because of iatrogenic causes than the concordant twins. Among dichorionic twins, discordant twins had lower birth weight rates and higher hospitalization rates and morbidities than concordant twins. Among monochorionic twins, discordant twins had a lower birth weight and higher neonatal mortality than concordant twins. The neonatal size was not a predictor of neurodevelopment in this group. Based on the logistic regression analysis, male sex, respiratory distress syndrome, and bronchopulmonary dysplasia were risk factors for the neurodevelopmental delay; birth weight discordancy was significant only in dichorionic twins. Conclusions: Perinatal outcomes in discordant twins may be poor, and neurodevelopment 1 year after birth was worse in discordant twins than in concordant twins. Discordancy in twins can be a risk factor for neurodevelopmental delay.

Tuning Hot Carrier Dynamics of InP/ZnSe/ZnS Quantum Dots by Shell Morphology Control.

Isotropic InP/ZnSe/ZnS quantum dots (QDs) are prepared at a high reaction temperature, which facilitates ZnSe shell growth on random facets of the InP core. Fast crystal growth enables stacking faults elimination, which induces anisotropic growth, and as a result, improves the photoluminescence (PL) quantum yield by nearly 20%. Herein, the effect of the QD morphology on photophysical properties is investigated by observing the PL blinking and ultrafast charge carrier dynamics. It is found that hot hole trapping is considerably suppressed in isotropic InP QDs, indicating that the stacking faults in the anisotropic InP/ZnSe structures act as defects for luminescence. These results highlight the importance of understanding the correlation between QD shapes and hot carrier dynamics, and present a way to design highly luminescent QDs for further promising display applications.

Extracellular vesicles derived from fibroblasts promote wound healing by optimizing fibroblast and endothelial cellular functions.

Extracellular vesicles (EVs) have been exhibited as promising candidates for delivering endogenous therapeutic cargos for regenerative therapies. Fibroblasts could be candidate source cells for EVs, to investigate their therapeutic effects in wound healing. Here we demonstrated the isolation and characterization of fibroblast-derived (L929 cell line) EVs (L929-EVs). Furthermore, L929-EVs treatment showed pro-wound healing effects in vitro by enhancing proliferation, migration, and scarless wound healing related genes in fibroblast cells. L929-EVs treatment also enhanced the migration and tube formation of endothelial cells. The combination of L929-EVs with fibrin glue accelerated wound healing in the mouse skin wound model by enhancing collagen formation, collagen maturation, and blood vessels in the wounded skin. The role of fibroblast-derived EVs in wound healing could be an important phenomenon, and fibroblast-derived EVs could be harnessed for wound healing therapies.

MicroRNA-365a/b-3p as a Potential Biomarker for Hypertrophic Scars.

The clinical aspects of hypertrophic scarring vary according to personal constitution and body part. However, the mechanism of hypertrophic scar (HS) formation remains unclear. MicroRNAs (miRNAs) are known to contribute to HS formation, however, their detailed role remains unknown. In this study, candidate miRNAs were identified and analyzed as biomarkers of hypertrophic scarring for future clinical applications. HSfibroblasts and normal skin fibroblasts from patients were used for profiling and validation of miRNAs. An HS mouse model with xenografted human skin on nude mice was established. The miRNA expression between normal human, normal mouse, and mouse HS skin tissues was compared. Circulating miRNA expression levels in the serum of normal mice and mice with HSs were also analyzed. Ten upregulated and twenty-one downregulated miRNAs were detected. Among these, miR-365a/b-3p and miR-16-5p were identified as candidate miRNAs with statistically significant differences; miR-365a/b-3p was significantly upregulated (p = 0.0244). In mouse studies, miR-365a/b-3p expression levels in skin tissue and serum were higher in mice with HSs than in the control group. These results indicate that miRNAs contribute to hypertrophic scarring and that miR-365a/b-3p may be considered a potential biomarker for HS formation.

Hypoxia Promotes Angiogenic Effect in Extracranial Arteriovenous Malformation Endothelial Cells.

Arteriovenous malformation (AVM) is characterized by high-flow blood vessels connecting arteries and veins without capillaries. This disease shows increased angiogenesis and a pathophysiological hypoxic environment in proximal tissues. Here, we analyzed the effects of hypoxia on angiogenesis in the endothelial cells (ECs) of AVM and normal tissues. ECs from human normal and AVM tissues were evaluated using immunocytochemistry with CD31. In vitro tube formation under hypoxia was tested in both ECs using Matrigel. The relative expression of angiogenesis-related genes was measured using real-time PCR. Under normoxia, CD31 was significantly higher in AVM ECs (79.23 ± 0.65%) than in normal ECs (74.15 ± 0.70%). Similar results were observed under hypoxia in AVM ECs (63.85 ± 1.84%) and normal ECs (60.52 ± 0.51%). In the tube formation test under normoxic and hypoxic conditions, the junction count and total vessel length were significantly greater in AVM ECs than normal ECs. Under both normoxia and hypoxia, the angiogenesis-related gene FSTL1 showed a significantly higher expression in AVM ECs than in normal ECs. Under hypoxia, CSPG4 expression was significantly lower in AVM ECs than in normal ECs. Accordingly, the angiogenic effect was increased in AVM ECs compared with that in normal ECs. These results provide a basic knowledge for an AVM treatment strategy.

Correlation between Maternal Weight Gain in Each Trimester and Fetal Growth According to Pre-Pregnancy Maternal Body Mass Index in Twin Pregnancies.

Background andObjectives: This study aimed to determine the correlation between maternal weight gain in each trimester and fetal growth according to pre-pregnancy maternal body mass index in twin pregnancies. Materials and Methods: We conducted a retrospective review of the medical records of 500 twin pregnancies delivered at 28 weeks' gestation or greater at a single tertiary center between January 2011 and December 2020. We measured the height, pre-pregnant body weight, and maternal body weight of women with twin pregnancies and evaluated the relationship between the maternal weight gain at each trimester and fetal growth restriction according to pre-pregnancy body mass index. Results: The overweight pregnant women were older than the normal or underweight pregnant women, and the risk of gestational diabetes was higher. The underweight pregnant women were younger, and the incidence of preterm labor and short cervical length during pregnancy was higher in the younger group. In normal weight pregnant women, newborn babies' weight was heavier when their mothers gained weight, especially when they gained weight in the second trimester. Mothers' weight gain in the first trimester was not a significant factor to predict fetal growth. The most predictive single factor for the prediction of small neonates was weight gain during 24−28 and 15−18 weeks, and the cutoff value was 6.2 kg (area under the curve 0.592, p < 0.001). Conclusions: In twin pregnancy, regardless of the pre-pregnant body mass index, maternal weight gain affected fetal growth. Furthermore, weight gain in the second trimester of pregnancy is considered a powerful indicator of fetal growth, especially in normal weight pregnancies.

Acute Twin-to-Twin Transfusion Syndrome Resulting in Fetal Bradycardia and Neonatal Death: A Case Report.

In monochorionic twins with no evidence of chronic twin-to-twin transfusion syndrome or twin anemia-polycythemia sequence, a sudden onset of fetal transfusion syndrome after the second trimester of pregnancy is defined as acute twin-to-twin transfusion syndrome. Labor pain, change in the fetal position, and birth order are known risk factors for this condition, and the hemoglobin level of the donor twin is usually reported to be <12 g/dL. We report a recent case of acute twin-to-twin transfusion syndrome without effective labor pain causing cervical changes, resulting in fetal bradycardia and neonatal death after birth; however, the anemia of the donor twin was not as severe as has been reported previously in twin-to-twin transfusion syndrome cases.

Oscillatory shear stress promotes angiogenic effects in arteriovenous malformations endothelial cells.

BACKGROUND: Vascular endothelial cells (ECs) are subject to continuous shear stress due to blood circulation. Mechanical stress due to high shear flow can also cause arteriovenous malformation (AVM) when ECs respond hyper-sensitively to shear flow. This study was conducted to test the hypothesis that angiogenesis could be promoted in response to mechanical stress via regulation of pro-angiogenic factors in AVM cells. METHODS: ECs were extracted from the tissue samples from six AVM patients and six normal patients. Shear stress at 7 dynes/cm2 were applied for 24 h. Before and after application of shear stress to each group, RT-PCR was performed to access the expression levels of angiopoietin2(AGP2), aquaporin1(AQP1) and TGFßR1. Immunofluorescences was also performed to evaluate the level of protein expressions. RESULTS: In both normal and AVM tissues, AGP2 and TGFßR1 under the shear stress showed increased expression in the ECs compared to the non-sheared samples. When AVMs and normal arterial vasculature were compared, the expression levels of both AGP2 and TGFßR1 in AVMs were higher when compared to normal arterial vasculature with or without shear stress. Immunofluorescence-based protein analysis also confirmed shear-induced AGP2 and TGFßR1 in both samples of normal and AVM patients. CONCLUSIONS: AVMs exhibited higher sensitivity to shear stress by producing higher expressions of some marked genes and proteins that regulate the endothelial functions upon exposure to shear stress. While the physiological mechanism for AVMs remain elusive, our study shows the plausibility of physical stress imposed by the shearing flow can cause the occurrence of AVMs.

Osteogenesis of 3D-Printed PCL/TCP/bdECM Scaffold Using Adipose-Derived Stem Cells Aggregates; An Experimental Study in the Canine Mandible.

Three-dimensional (3D) printing is perceived as an innovative tool for change in tissue engineering and regenerative medicine based on research outcomes on the development of artificial organs and tissues. With advances in such technology, research is underway into 3D-printed artificial scaffolds for tissue recovery and regeneration. In this study, we fabricated artificial scaffolds by coating bone demineralized and decellularized extracellular matrix (bdECM) onto existing 3D-printed polycaprolactone/tricalcium phosphate (PCL/TCP) to enhance osteoconductivity and osteoinductivity. After injecting adipose-derived stem cells (ADSCs) in an aggregate form found to be effective in previous studies, we examined the effects of the scaffold on ossification during mandibular reconstruction in beagle dogs. Ten beagles were divided into two groups: group A (PCL/TCP/bdECM + ADSC injection; n = 5) and group B (PCL/TCP/bdECM; n = 5). The results were analyzed four and eight weeks after intervention. Computed tomography (CT) findings showed that group A had more diffuse osteoblast tissue than group B. Evidence of infection or immune rejection was not detected following histological examination. Goldner trichrome (G/T) staining revealed rich ossification in scaffold pores. ColI, Osteocalcin, and Runx2 gene expressions were determined using real-time polymerase chain reaction. Group A showed greater expression of these genes. Through Western blotting, group A showed a greater expression of genes that encode ColI, Osteocalcin, and Runx2 proteins. In conclusion, intervention group A, in which the beagles received the additional ADSC injection together with the 3D-printed PCL/TCP coated with bdECM, showed improved mandibular ossification in and around the pores of the scaffold.

Surface modification of solid-state nanopore by plasma-polymerized chemical vapor deposition of poly(ethylene glycol) for stable device operation.

Biopolymer adsorption onto a membrane is a significant issue in the reliability of solid-state nanopore devices, since it degrades the device performance or promotes device failure. In this work, a poly(ethylene glycol) (PEG) layer was coated on a silicon nitride (SiNx) membrane by plasma-polymerized vapor deposition to inhibit biopolymer adsorption. From optical observations, the deposited PEG layer demonstrated increased hydrophilicity and anti-adsorption property compared to the SiNx surface. Electrical properties of the PEG/SiNx nanopore were characterized, showing Ohmic behavior and a 6.3 times higher flicker noise power due to the flexible conformation of PEG in water. Antifouling performance of each surface was analyzed by measuring the average time from voltage bias to the first adsorption during DNA translocation experiments, where the modified surface enabled two times prolonged device operation. The time to adsorption was dependent on the applied voltage, implying adsorption probability was dominated by the electrophoretic DNA approach to the nanopore. DNA translocation behaviors on each surface were identified from translocation signals, as the PEG layer promoted unfolded and fast movement of DNA through the nanopore. This work successfully analyzed the effect of the PEG layer on DNA adsorption and translocation in solid-state nanopore experiments.

Electrical properties of graphene/In2O3 bilayer with remarkable uniformity as transparent conducting electrode.

A graphene/In2O3 bilayer (termed as GI-bilayer) is proposed as a transparent conducting electrode with remarkably improved areal-uniformity. To fabricate this new structure, an In2O3 layer with a thickness of less than 50 nm was grown by atomic layer deposition and then a graphene layer was grown by chemical vapor deposition and subsequently transferred onto the as-grown In2O3 layer. Electrical and optical properties of the GI-bilayer were systematically studied to verify effects of the underlying In2O3 layer. Hall measurements and following analysis showed a conductance enhancement of the GI-bilayer owing to p-type doping of graphene. Specifically, Raman analysis and ultraviolet photoelectron spectroscopy were performed to prove p-type doping of the graphene in the GI-bilayer. In addition, the GI-bilayer exhibited the significantly improved uniformity of the sheet resistance compared to that of a conventional monolayer of graphene. There was a duality on the role of the In2O3 underlayer in the GI-bilayer. It acted as a dopant layer to the graphene and lowered the sheet resistance from 863 to 510 Ω/sq as well as compensated microscale defects on graphene. More importantly, the In2O3 underlayer resulted in the extremely reduced standard deviation of sheet resistance from 150 to 7.5 Ω/sq over the area of 49 cm2.

Exposure to cold airflow alters skin pH and epidermal filaggrin degradation products in children with atopic dermatitis.

BACKGROUND: We aimed to evaluate the influence of cold airflow from the air conditioner on skin barrier function and filaggrin degradation products (FDPs) in children with atopic deramtitis (AD). METHODS: In a case-control study, 28 children with AD and 12 normal children without AD were exposed to one of two air conditioner modes (conventional or wind-free) for 2 h. Skin temperature, transepidermal water loss (TEWL), and skin pH were measured on right cheek and forearm at pre- and post-exposure time points. We also measured filaggrin and FDPs from the volar surface of the forearm. RESULTS: In AD patients, skin temperature on the forearm decreased after exposure to the conventional and wind-free modes (P < 0.001 and P = 0.026), and TEWL on the cheek and the forearm decreased in the wind-free mode (P = 0.037 and 0.002). Skin pH on the cheek increased only after exposure to the conventional mode in AD group (P = 0.002). However, no changes in TEWL and skin pH were found after exposure to either the conventional or the wind-free mode in the control group. In AD children, the levels of pyrrolidone carboxylic acid (PCA) and cis-urocanic acid (UCA) were reduced only after exposure to the conventional mode (all P = 0.033). The percent changes of PCA and cis-UCA were higher in the AD group than those in the control group after exposure to conventional mode (P = 0.029 and 0.046). CONCLUSIONS: Skin barrier function in children with AD may be altered by the exposure to cold airflow from a conventional air conditioner.

Inhalation toxicity of benzalkonium chloride and triethylene glycol mixture in rats.

Benzalkonium chloride (BAC), a disinfectant, and triethylene glycol (TEG), an organic solvent/sanitizer, are frequently combined in commercially available household sprays. To assess the respiratory effect of this combination, Sprague-Dawley rats were exposed to an aerosol containing BAC (0.5%, w/v) and TEG (10%, w/v) for up to 2 weeks in a whole-body inhalation chamber. BAC (4.1-4.5 mg/m3, sprayed from 0.5% solution) promoted pulmonary cell damage and inflammation as depicted by the increase in total protein, lactate dehydrogenase, polymorphonuclear leukocytes, and macrophage inflammatory protein-2 in the bronchoalveolar lavage fluid, whereas TEG (85.3-94.5 mg/m3, sprayed from 10% solution) did not affect the lung. Rats exposed to the BAC/TEG mixture for 2 weeks showed severe respiratory symptoms (sneezing, wheezing, breath shortness, and chest tightness), but no lung damage or inflammation was observed. However, significant ulceration and degenerative necrosis were observed in the nasal cavities of rats repeatedly exposed to the BAC/TEG mixture. The mass median aerodynamic diameters of the aqueous, BAC, TEG and BAC/TEG aerosols were 1.24, 1.27, 3.11 and 3.24 µm, respectively, indicating that TEG-containing aerosols have larger particles than those of the aqueous and BAC alone aerosols. These results suggest that the toxic effects of BAC and BAC/TEG aerosols on the different respiratory organs may be associated with the difference in particle diameter, since particle size is important in determining the deposition site of inhaled materials.

Detection of metal corrosion characteristics in chlorine solution using solid state nanopore.

Nanopore structures were originally proposed for detection of biomolecule translocation through nanometer-scale pores that perforate membranes by transient changes in ionic current. In this study, these changes are utilized to detect corrosion of different metals in aqueous chlorine media. The corrosion behaviors of Cu, Al, Ti, and Cr were analyzed by monitoring the changes in ion current resulting from ion concentration variations in solutions due to corrosion of the metals. We observed that the Cu layer passivated by CuO x was severely corroded when a drastic change of ion current was induced, from 10 to 30 nS to the level of 104 nS, as soon as the bias voltage was applied. In the case of Al passivated by thin AlO x , the conductance increased from 10-30 to 166 ± 52 nS and became saturated. Highly localized pitting corrosion was observed on the periphery of the nanopore, where the electrical field was most concentrated. Finally, we observed that Ti and Cr passivated by oxide showed long-term stability without corrosion in 1 M KCl in the pH range of 4-11.