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1.
Emerg Infect Dis ; 30(6): 1285-1288, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38703022

RESUMEN

We isolated novel reassortant avian influenza A(H5N6) viruses containing genes from clade 2.3.4.4b H5N1 virus and low pathogenicity avian influenza viruses in carcasses of whooper swans and bean geese in South Korea during December 2023. Neuraminidase gene was from a clade 2.3.4.4b H5N6 virus infecting poultry and humans in China.


Asunto(s)
Animales Salvajes , Aves , Virus de la Influenza A , Gripe Aviar , Filogenia , Animales , Gripe Aviar/virología , Gripe Aviar/epidemiología , República de Corea/epidemiología , Animales Salvajes/virología , Virus de la Influenza A/genética , Virus de la Influenza A/clasificación , Aves/virología , Virus Reordenados/genética , Historia del Siglo XXI , Humanos , Neuraminidasa/genética
2.
Acta Ophthalmol ; 2024 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-38706195

RESUMEN

PURPOSE: To investigate the long-term efficacy and safety of intravitreal brolucizumab (BRZ) injections in patients with typical neovascular age-related macular degeneration (typical nAMD) and polypoidal choroidal vasculopathy (PCV). METHODS: This multicentre retrospective study included 401 eyes of 398 patients with nAMD who received BRZ injection(s), with a follow-up duration of ≥12 months. Changes in best-corrected visual acuity (BCVA), retinal fluid evaluation and central subfield thickness (CST) on optical coherence tomography were assessed. The efficacy of BRZ was compared between typical nAMD and PCV groups. RESULTS: Analyses were conducted with 280 eyes of 278 patients with typical nAMD and 121 eyes of 120 patients with PCV (mean age, 71.1 ± 8.6 years). 29 eyes (7.2%) were treatment naïve. The mean follow-up period was 15.3 ± 2.8 months; the mean number of BRZ injections within 1 year was 4.5 ± 1.7. BCVA was maintained during the follow-up period, and CST significantly improved from the first injection month and was maintained for 12 months in both the typical nAMD and PCV groups. The dry macula proportion increased from 2.7% at baseline to 56.1% at 1 month and 42.9% at 12 months. Among the 18 eyes that underwent indocyanine green angiography both before and after treatment, 10 (55.6%) showed polyp regression. Overall, the incidence of intraocular inflammation (IOI), retinal vasculitis and occlusive retinal vasculitis was 9.4% (38 eyes), 1.2% (5 eyes) and 0.5% (2 eyes), respectively. IOI occurred from the first to the sixth injections, with an average IOI onset of 28.5 ± 1.4 days. All eyes achieved IOI resolution, although the two eyes with occlusive retinal vasculitis showed a severe visual decline after IOI resolution. CONCLUSION: Brolucizumab was effective in maintaining BCVA and managing fluid in eyes with nAMD for up to 1 year, exhibiting a high polyp regression rate. However, the not uncommon incidence of IOI and the severe visual decline caused by the rare occlusive retinal vasculitis following BRZ treatment underscore the importance of careful monitoring and timely management.

4.
One Health ; 18: 100719, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38585666

RESUMEN

The winter of 2020-2021 in South Korea witnessed severe outbreaks of Highly Pathogenic Avian Influenza (HPAI) viruses, specifically multiple genotypes of the H5N8 subtype. These outbreaks prompted an extensive investigation into the genetic characteristics and evolutionary dynamics of these viruses. Under the auspices of the National Institute of Wildlife Disease Control and Prevention (NIWDC), we conducted a nationwide surveillance program, collecting 7588 specimens from diverse wild bird habitats. Influenza A viruses were isolated at a rate of 5.0%, with HPAI H5N8 viruses accounting for 38.5% of isolates, predominantly found in wild bird carcasses (97.3%). Genetic analysis revealed the emergence of novel HPAI genotypes due to genetic reassortment events. G1 and G2 viruses were separately introduced into Korea, with G1 viruses displaying dynamic behavior, resulting in diverse sub-genotypes (G1-1 to G1-5) and mainly isolated from clinical specimens. Conversely, the G2 virus, introduced later, became the dominant strain consistently isolated mainly from bird carcasses (88.9%). These findings underscore the emergence of numerous novel HPAI genotypes shaped by multiple reassortment events in high-density wintering grounds of migratory birds. These sites act as hotspots for genetic exchanges, significantly influencing avian ecology, including resident bird species, and contributing to HPAI H5N8 evolution. The genetic diversity and ongoing evolution of these viruses highlight the need for vigilant surveillance and adaptive control measures. Recognizing the potential spillover to human populations, a One Health approach is essential to mitigate the evolving threats posed by avian influenza.

5.
Emerg Infect Dis ; 30(2): 299-309, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38215495

RESUMEN

During October 2022-March 2023, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.4b virus caused outbreaks in South Korea, including 174 cases in wild birds. To understand the origin and role of wild birds in the evolution and spread of HPAI viruses, we sequenced 113 HPAI isolates from wild birds and performed phylogenetic analysis. We identified 16 different genotypes, indicating extensive genetic reassortment with viruses in wild birds. Phylodynamic analysis showed that the viruses were most likely introduced to the southern Gyeonggi-do/northern Chungcheongnam-do area through whooper swans (Cygnus cygnus) and spread southward. Cross-species transmission occurred between various wild bird species, including waterfowl and raptors, resulting in the persistence of HPAI in wild bird populations and further geographic spread as these birds migrated throughout South Korea. Enhanced genomic surveillance was an integral part of the HPAI outbreak response, aiding in timely understanding of the origin, evolution, and spread of the virus.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Gripe Aviar , Gripe Humana , Animales , Humanos , Subtipo H5N1 del Virus de la Influenza A/genética , Filogenia , Animales Salvajes , Aves , Gripe Humana/epidemiología , Patos , República de Corea/epidemiología
6.
Ophthalmic Res ; 67(1): 9-22, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38091967

RESUMEN

INTRODUCTION: The objective of this study was to investigate the clinical characteristics and genetic spectrum of adult-onset cone/cone-rod dystrophy (AOCD/AOCRD) in Korean individuals. METHODS: This is a single-center, retrospective cross-sectional study. We analyzed 22 individuals with genetically confirmed cone dystrophy, with symptoms beginning after 30 years of age. All patients underwent comprehensive ophthalmic and electrophysiological examinations. Exome sequencing of 296 genes associated with inherited retinal disease was performed. The clinical features of patients with AOCD/AOCRD and the causative genes and variants detected by exome sequencing were analyzed. RESULTS: The median age at the first visit was 52 years (range, 31-76 years), and the most common initial symptom was reduced visual acuity. In most cases, fundus photography showed a bull's eye pattern with foveal sparing, consistent with perifoveal photoreceptor loss on optical coherence tomography. We identified disease-causing variants in six genes: RP1, CRX, CDHR1, PROM1, CRB1, and GUCY2D. Pathogenic variants in RP1, CRX, and CDHR1 were identified in 77% of the AOCD/AOCRD cases, including p.Cys1399LeufsTer5, p.Arg1933Ter, and p.Ile2061SerfsTer12 in RP1; p.Ter300GlnextTer118 in CRX; and p.Glu201Lys in CDHR1. No characteristic imaging differences were observed for any of the causative genes. Most of the RP1-related AOCD/AOCRD cases showed a decreased amplitude only in the photopic electroretinogram (ERG), whereas CRX-related AOCD/AOCRD cases showed a slightly decreased amplitude in both the scotopic and photopic ERGs. CONCLUSION: In case of visual impairment with bull's eye pattern of RPE atrophy recognized after the middle age, a comprehensive ophthalmic examination and genetic test should be considered, with the possibility of AOCD/AOCRD in East Asians.


Asunto(s)
Distrofias de Conos y Bastones , Adulto , Persona de Mediana Edad , Humanos , Anciano , Distrofias de Conos y Bastones/diagnóstico , Distrofias de Conos y Bastones/genética , Distrofias de Conos y Bastones/patología , Estudios Retrospectivos , Estudios Transversales , Linaje , Mutación , Electrorretinografía , Tomografía de Coherencia Óptica , Fenotipo , Proteínas del Ojo/genética , Proteínas de la Membrana/genética , Proteínas del Tejido Nervioso/genética , Proteínas Relacionadas con las Cadherinas
7.
Ann Lab Med ; 44(3): 289-293, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38087945

RESUMEN

Although WHO declared the end of the public health emergency for coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), XBB lineages continue to evolve and emerge globally. In particular, XBB.1.5 and XBB.1.16 are raising concerns because of their high immune evasion, leading to apprehensions regarding vaccine efficacy reduction and potential reinfection. We aimed to investigate the COVID-19 outbreak in Korea and predict the likelihood of reinfection by testing neutralizing activity against live viruses from the S clade and 19 Omicron sublineages. We found a significant risk of infection with the currently prevalent XBB lineage for individuals who were either vaccinated early or infected during the initial Omicron outbreak. Vaccinated individuals were better equipped than unvaccinated individuals to produce neutralizing antibodies for other SARS-CoV-2 variants upon infection. Therefore, unvaccinated individuals do not easily develop neutralizing activity against other variants and face the highest risk of reinfection by the XBB lineage. Our study provides important information to facilitate the development of strategies for monitoring populations that would be the most susceptible to new COVID-19 outbreaks.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , Reinfección , Brotes de Enfermedades , Anticuerpos Antivirales
8.
Front Vet Sci ; 10: 1229369, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37808111

RESUMEN

Transmissible spongiform encephalopathies (TSEs) have been reported in a broad spectrum of hosts. The genetic polymorphisms and characteristics of the prion protein (PRNP) gene have a vital impact on the development of TSEs. Notably, natural TSE infection cases have never been reported in rabbits, and genetic variations of the leporine PRNP gene have not been investigated to date. To identify leporine PRNP gene polymorphism, we performed amplicon sequencing in 203 rabbits. We report a novel single nucleotide polymorphism on the leporine PRNP gene. In addition, we performed a comparative analysis of amino acid sequences of prion protein (PrP) across several hosts using ClustalW2. Furthermore, we evaluated the effect of changes of unique leporine PrP amino acids with those conserved among various species using Swiss-Pdb Viewer. Interestingly, we found seven unique leporine amino acids, and the change of unique leporine amino acids with those conserved among other species, including S175N, Q221K, Q221R, A226Y, A230G, and A230S, was predicted to reduce hydrogen bonds in leporine PrP.

9.
Materials (Basel) ; 16(15)2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37569963

RESUMEN

Metal injection molding (MIM) is a representative near-net-shape manufacturing process that fabricates advanced geometrical components for automobile and device industries. As the mechanical performance of an MIM product is affected by green-part characteristics, this work investigated the green part of pure copper processed with MIM using the injection temperature of ~180 °C and injection pressure of ~5 MPa. A computational analysis based on the Moldflow program was proposed to simulate the effectivity of the process by evaluating the confidence of fill, quality prediction, and pressure drop of three distinctive regions in the green part. The results showed that the ring and edge regions of the green parts showed localized behavior, which was related to processing parameters including the position of the gate. A microstructural observation using scanning electron microscopy and a 3D X-ray revealed that both the surface and body matrix consisted of pores with some agglomeration of micro-pores on the edges and ring part, while any critical defects, such as a crack, were not found. A microhardness analysis showed that the three regions exhibited a reasonable uniformity with a slight difference in one specific part mainly due to the localized pore agglomeration. The simulation results showed a good agreement with the microstructures and microhardness data. Thus, the present results are useful for providing guidelines for the sound condition of MIM-treated pure copper with a complex shape.

10.
Materials (Basel) ; 16(10)2023 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-37241394

RESUMEN

This investigation studied the effect of reduction sequence during rolling of ferritic stainless steel on texture and anisotropy. A series of thermomechanical processes were performed on the present samples utilizing rolling deformation, with a total height reduction of 83% but with different reduction sequences, 67% + 50% (route A) and 50% + 67% (route B). Microstructural analysis showed that no significant difference was found in terms of the grain morphology between route A and route B. In terms of the texture, as compared to route A, route B developed a sharper texture on all components along the γ-fiber and a considerably higher fraction of boundaries that displayed 38°111 misorientations with respect to the surrounding deformed grains. In consequence, optimal deep drawing properties were achieved, where rm was maximized and Δr was minimized. Moreover, despite the similar morphology between the two processes, the resistance toward ridging was improved in the case of route B. This was explained in relation to the selective growth-controlled recrystallization, which favors the formation of microstructure with homogeneous distribution of the <111>//ND orientation.

11.
Retina ; 43(6): 1010-1018, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36763981

RESUMEN

PURPOSE: To investigate the efficacy and safety of 3D heads-up display (3D-HUD) vitrectomy compared with conventional microscopy (CM) vitrectomy in epiretinal membrane (ERM) surgery. METHODS: Epiretinal membrane removal with or without internal limiting membrane (ILM) peeling was performed using a 3D-HUD or CM system. The mean changes in best-corrected visual acuity (BCVA) and in central macular thickness (CMT) and postoperative complications were assessed. RESULTS: Baseline demographics were comparable except for the follow-up period. Both BCVA and CMT improved at the final visit (all P < 0.05). The ERM recurrence and dissociated optic nerve fiber layer (DONFL) rates were lower in the 3D group (both P < 0.05). conventional microscopic vitrectomy (odds ratio [OR] = 12.86, P = 0.02) and absence of ILM peeling (OR = 45.25, P < 0.05) were associated with ERM recurrence. In the DONFL, CM vitrectomy (OR = 1.98, <0.05) and combined phacovitrectomy (OR = 2.33, P = 0.03) were analyzed as risk factors for DONFL. CONCLUSION: The improvement in BCVA and CMT in ERM surgery using a 3D-HUD is comparable with that of CM vitrectomy, with a significantly low rate of ERM recurrence and DONFL occurrence. Therefore, 3D vitrectomy might have an advantage for ERM surgery.


Asunto(s)
Membrana Epirretinal , Vitrectomía , Humanos , Vitrectomía/métodos , Membrana Epirretinal/cirugía , Membrana Basal/cirugía , Ojo , Complicaciones Posoperatorias/cirugía , Estudios Retrospectivos , Tomografía de Coherencia Óptica
12.
Ophthalmologica ; 246(3-4): 192-202, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36720210

RESUMEN

INTRODUCTION: The aim of the study was to determine the short-term real-world safety and efficacy of intravitreal brolucizumab injections in Korean patients with neovascular age-related macular degeneration (nAMD). METHODS: This multicenter retrospective study involved 294 eyes (treatment naïve 20 eye [6.8%] and nontreatment naïve 274 eyes [93.2%]) of 290 patients from 13 hospitals or retinal centers in South Korea. Patients with nAMD who received brolucizumab injection(s) between April 1 and November 30, 2021, with a follow-up ≥1 month, were included. Primary outcomes were safety, incidence of intraocular inflammation (IOI), and potential risk factors. The secondary outcome was efficacy, i.e., change in best-corrected visual acuity (BCVA) and optical coherence tomography-measured macular thickness and retinal fluid. RESULTS: The mean age was 71.63 ± 8.66. The follow-up period was 2.38 ± 0.79 months. The mean number of brolucizumab injections during the follow-up was 1.52 ± 0.58. The overall incidence of IOI was 13.9% (n = 41 eyes). Most IOI cases were of anterior uveitis (8.8%, 26 eyes), followed by retinal vasculitis (2.4%, seven eyes) and occlusive retinal vasculitis (0.3%, one eye). Most eyes showed IOI resolution (n = 40, 97.5%) and BCVA restoration (n = 39, 95.1%) with or without corticosteroid treatment during the follow-up. Age, sex, IOI history, or other anti-vascular endothelial growth factor injection histories were not associated with the occurrence of IOI. However, only thin subfoveal choroidal thickness (SFCT) was associated with the occurrence of IOI (odds ratio = 0.995, p = 0.020). BCVA at 1 month improved from baseline (baseline 0.518 ± 0.356 vs. 1 month 0.503 ± 0.383, p = 0.023), but the improvement was not maintained. Anatomical improvement was significant after 3 months. CONCLUSION: In Korean patients with nAMD, the incidence of IOI following brolucizumab injections was 13.9%. IOI was well-controlled with or without steroid treatment. Most IOI eyes (95.1%) were restored to the level of vision before. IOI occurrence and occlusive vasculitis was rare. In the short term, brolucizumab injection effectively improved vision at 1 month and dried retinal fluid for 3 months.


Asunto(s)
Degeneración Macular , Vasculitis Retiniana , Humanos , Persona de Mediana Edad , Anciano , Anciano de 80 o más Años , Estudios Retrospectivos , Inflamación , Retina
13.
Toxicol Res (Camb) ; 11(1): 88-100, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-35237414

RESUMEN

The retina plays a key role in human vision. It is composed of cells that are essential for vision signal generation. Thus far, conventional medications have been ineffective for treating retinal diseases because of the intrinsic blood-retinal barrier. Nanoparticles (NPs) are promising effective platforms for ocular drug delivery. However, nanotoxicity in the retinal tissue has not received much attention. This study used R28 cells (a retinal precursor cell line that originated from rats) to investigate the safety of two commonly used types of NPs: silica nanoparticles (SiO2NPs, 100 nm) and titanium dioxide nanoparticles (TiO2NPs, 100 nm). Cellular viability and reactive oxygen species generation were measured after 24, 48, and 72 h of exposure to each NP. Cellular autophagy and the mTOR pathways were evaluated. The retinal toxicity of the NPs was investigated in vivo in rat models. Both types of NPs were found to induce significant dose-dependent toxicity on the R28 cells. A significant elevation of reactive oxygen species generation was also observed. Increased autophagy and decreased mTOR phosphorylation were observed after SiO2NPs and TiO2NPs exposure. The diffuse apoptosis of the retinal cellular layers was detected after intravitreal injection.

14.
Foods ; 11(3)2022 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-35159566

RESUMEN

Pesticides which are diluted and sprayed according to the pre-harvest interval (PHI) are generally decomposed and lost through various factors and pathways, and the leftover pesticides are known as residual pesticides. This study aims to determine the dissipation of residual amounts of dinotefuran, fluazinam, indoxacarb, and thiacloprid in persimmon and the changes in the concentration of various processing products. Pesticide spraying is performed in accordance with the GAP (good agricultue practice) of Korea, and the processed products are manufactured using a conventional method after removing the skin of persimmons. The modified QuEchERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method and an optimized method using LC-MS/MS (liquid chromatography mass spectrometry) is implemented to analyze the residual pesticides. The linearity, recovery, and LOQ (limit of quantitation) are presented to verify the analysis method. The amount of residual pesticides tested decreases significantly in a time-dependent manner, regardless of the minimal dilution effect present due to growth. The residual concentration does not vary significantly during the processing stage despite the removal of the systemic pesticides, dinotefuran and thiacloprid. The residues of non-systemic pesticides, fluazinam and indoxacarb, are typically removed by the peeling removal and processing methods. The reduction factor of dinotefuran, whose residual concentration is increased, is less than 1, and the absolute amount of pesticides is decreased through processing. The results of this study can be used as the scientific basis data to ensure the safety of residual pesticides in processed products in the future.

15.
Sci Rep ; 11(1): 24115, 2021 12 16.
Artículo en Inglés | MEDLINE | ID: mdl-34916593

RESUMEN

Intraocular antibiotic delivery is an important technique to prevent bacterial infection after ophthalmic surgery, such as cataract surgery. Conventional drug delivery methods, such as antibiotic eye drops, have limitations for intraocular drug delivery due to the intrinsic barrier effect of the cornea. Therefore, frequent instillation of antibiotic eyedrops is necessary to reach a sufficient bactericidal concentration inside the eye. In this study, an intraocular implant, MXF-HA, that combines hyaluronic acid (HA) and moxifloxacin (MXF) was developed to increase the efficiency of intraocular drug delivery after surgery. MXF-HA is manufactured as a thin, transparent, yellow-tinted membrane. When inserted into the eye in a dry state, MXF-HA is naturally hydrated and settles in the eye, and the MXF contained therein is delivered by hydrolysis of the polymer over time. It was confirmed through in vivo experiments that MXF delivery was maintained in the anterior chamber of the eye at a concentration sufficient to inhibit Pseudomonas aeruginosa and Staphylococcus aureus for more than 5 days after implantation. These results suggest that MXF-HA can be utilized as a potential drug delivery method for the prevention and treatment of bacterial infections after ophthalmic surgery.


Asunto(s)
Antibacterianos/administración & dosificación , Ácido Hialurónico/administración & dosificación , Bombas de Infusión Implantables , Moxifloxacino/administración & dosificación , Animales , Antibacterianos/farmacología , Infecciones Bacterianas/prevención & control , Extracción de Catarata/efectos adversos , Liberación de Fármacos , Farmacorresistencia Bacteriana , Moxifloxacino/farmacología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Pseudomonas aeruginosa/efectos de los fármacos , Conejos , Ratas , Staphylococcus aureus/efectos de los fármacos
16.
Materials (Basel) ; 14(11)2021 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-34199512

RESUMEN

Fly ash, the main component for controlled low-strength material (CLSM), has physical and chemical characteristics according to the resources used in the thermal power plant, and thus fly ash type can influence the physical and strength properties of CLSM. This study investigates the effect of fly ash type on the engineering properties of CLSM and establishes relationships between mechanical properties of CLSM and shear wave velocity (SWV) for long curing times. Six fly ashes with different physical properties and chemical components are used for preparing the CLSM mixtures. The air content, unit weight, flowability, and setting time of CLSM are measured. Unconfined compressive strength (UCS) and elastic modulus (E) are obtained from unconfined compressive tests, and SWV (Vs) is determined using a bender element-based wave measurement system. Experimental results show that the stiffness and strength characteristics of CLSM are relevant to the contents of two oxides (SiO2 and Al2O3) and the fineness of fly ash. Because the evolution of SWV is influenced by the fly ash type, the relationships UCS-Vs and E-Vs are well established. Thus, considering the fly ash type, shear wave monitoring may be effectively used for estimating strength and stiffness characteristics of CLSM.

17.
Sensors (Basel) ; 21(9)2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33925195

RESUMEN

Dynamic resistance, which can be used to express strength in the unit of stress and improve the reliability of the dynamic cone penetration test (DCPT), has been estimated by numerous methods. This study aims to compare different dynamic resistance estimation methods by using an instrumented dynamic cone penetrometer (IDCP). DCPTs are conducted using a standard dynamic cone penetrometer (DCP) and IDCP in the laboratory and field. Dynamic responses are obtained from the strain gauges and an accelerometer installed at the cone tip of the IDCP. The test results show that dynamic resistance is more efficient in distinguishing profiles than the dynamic cone penetration index. Among the methods to estimate the dynamic resistance at the cone tip, the force-velocity integration method and force integration method are more related to the conventional dynamic resistance considering the potential energy of the hammer than the force squared integration method. Additionally, the dynamic resistance estimated for a longer time period is more reliable, particularly for small driving rod lengths. Regarding the limitation of the dynamic response from an accelerometer in a previous study, the force-based dynamic resistance estimated for a longer time period can be used as the most reliable approach for further soil strength characterization.


Asunto(s)
Suelo , Reproducibilidad de los Resultados
18.
Sensors (Basel) ; 21(4)2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33572357

RESUMEN

Shear wave velocity and small-strain shear modulus are widely used as the mechanical properties of soil. The objective of this study is to develop a new shear wave monitoring system using a pair of piezoelectric ring benders (RBs) and to evaluate the suitability of RB in compacted soils compared with the bender element and ultrasonic transducer. The RB is a multilayered piezoelectric actuator, which can generate shear waves without disturbing soils. For five compacted soil specimens, the shear waves are monitored by using three different piezoelectric transducers. Results of time-domain response show that the output signals measured from the RB vary according to the water content of the specimen and the frequency of the input signal. Except at the water content of 9.3%, the difference in the resonant frequencies between the three transducers is not significant. The shear wave velocities for the RB are slightly greater than those for the other transducers. For the RB, the exponential relationship between the shear wave velocity and dry unit weight is better established compared with that of the other transducers. The newly proposed piezoelectric transducer RB may be useful for the evaluation of the shear wave velocity and small-strain shear modulus of compacted soils.

19.
Sci Rep ; 11(1): 2351, 2021 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-33504908

RESUMEN

Ocular surface diseases (OSD) can cause serious visual deterioration and discomfort. Commercial artificial tear solution containing hyaluronic acid (HA) show excellent biocompatibility and unique viscoelastic characteristics. Here, we developed a novel HA membrane (HAM) by chemical crosslinking using 1,4-butanediol diglycidyl ether for the effective treatment of OSDs. The main purpose of HAMs is to provide sustained release of HA to modulate the wound healing response in OSDs. The safety and efficacy of HAMs were investigated using primary cultured human corneal epithelial cells and various OSD rabbit models. In the dry state, the HAM is firm, transparent, and easy to manipulate. When hydrated, it swells rapidly with high water retention and over 90% transmission of visible light. Human corneal epithelial cells and rabbit eyes showed no toxic response to HAM. Addition of HAMs to the culture medium enhanced human corneal epithelial cell viability and expression of cell proliferation markers. Investigation of HAM wound healing efficacy using mechanical or chemical corneal trauma and conjunctival surgery in rabbits revealed that application of HAMs to the ocular surface enhanced healing of corneal epithelium and reduced corneal limbal vascularization, opacity and conjunctival fibrosis. The therapeutic potential of HAMs in various OSDs was successfully demonstrated.


Asunto(s)
Ácido Hialurónico/química , Membranas Artificiales , Animales , Línea Celular , Epitelio Corneal/química , Humanos , Microscopía Electrónica de Rastreo , Conejos , Espectroscopía Infrarroja por Transformada de Fourier , Cicatrización de Heridas/fisiología
20.
Artículo en Inglés | MEDLINE | ID: mdl-33430085

RESUMEN

This study determined residual buprofezin levels in fresh ginseng and evaluated their changes during processing. Supervised field trials were conducted at Yeongju, Geumsan, and Goesan, Korea. Buprofezin 12.5% EC was applied to 5-y ginseng in accordance with the Korean good agriculture practice (GAP). Samples were collected at 0, 7, 14, 21, and 30 d after the final application. On day 14 (GAP-equivalent preharvest date), the ginseng was processed to obtain dried and red ginseng. The average buprofezin concentrations on day 0 were 0.076 (Yeongju), 0.055 (Geumsan), and 0.078 mg kg-1 (Goesan). Residual concentrations increased as ginseng was processed into dried and red ginseng. Residue levels in dried ginseng manufactured by hot air drying were higher than in red ginseng obtained by steaming, hot air, and sunlight drying. However, the absolute amount of pesticides decreased by approximately 20-30% as a result of calculating the reduction factor considering the dry yield and moisture content. Therefore, the residual concentration in processed products may vary depending on the processing method, and it is deemed necessary to consider the processing yield and moisture content when evaluating the safety of residual pesticides in dried processed products.


Asunto(s)
Panax , Tiadiazinas , Desecación , República de Corea
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