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1.
BMC Oral Health ; 24(1): 775, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38987748

RESUMEN

Acrylic resins are widely used as the main components in removable orthodontic appliances. However, poor oral hygiene and maintenance of orthodontic appliances provide a suitable environment for the growth of pathogenic microorganisms. In this study, strontium-modified phosphate-based glass (Sr-PBG) was added to orthodontic acrylic resin at 0% (control), 3.75%, 7.5%, and 15% by weight to evaluate the surface and physicochemical properties of the novel material and its in vitro antifungal effect against Candida albicans (C. albicans). Surface microhardness and contact angle did not vary between the control and 3.75% Sr-PBG groups (p > 0.05), and the flexural strength was lower in the experimental groups than in the control group (p < 0.05), but no difference was found with Sr-PBG content (p > 0.05). All experimental groups showed an antifungal effect at 24 and 48 h compared to that in the control group (p < 0.05). This study demonstrated that 3.75% Sr-PBG exhibits antifungal effects against C. albicans along with suitable physicochemical properties, which may help to minimize the risk of adverse effects associated with harmful microbial living on removable orthodontic appliances and promote the use of various materials.


Asunto(s)
Resinas Acrílicas , Antifúngicos , Candida albicans , Vidrio , Ensayo de Materiales , Fosfatos , Estroncio , Propiedades de Superficie , Candida albicans/efectos de los fármacos , Resinas Acrílicas/química , Estroncio/farmacología , Estroncio/química , Antifúngicos/farmacología , Vidrio/química , Fosfatos/farmacología , Polimerizacion , Dureza , Resistencia Flexional , Humanos , Técnicas In Vitro
2.
Int J Mol Sci ; 24(13)2023 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-37445896

RESUMEN

Periodontitis is an inflammatory disease caused by microorganisms that induce the destruction of periodontal tissue. Inflamed and damaged tissue produces various inflammatory cytokines, which activate osteoclasts and induce alveolar bone loss and, eventually, tooth loss. Sirt6 expression suppresses inflammation and bone resorption; however, its role in periodontitis remains unclear. We hypothesized that Sirt6 has a protective role in periodontitis. To understand the role of Sirt6 in periodontitis, we compared periodontitis with ligature placement around the maxillary left second molar in 8-week-old control (C57BL/6J) male mice to Sirt6-overexpressing Tg (Sirt6Tg) mice, and we observed the resulting phenotypes using micro-CT. MDL801, a Sirt6 activator, was used as a therapy for periodontitis through oral gavage. Pro-inflammatory cytokines and increased osteoclast numbers were observed in alveolar bone tissue under periodontitis surgery. In the same condition, interestingly, protein levels from Sirt6 were the most downregulated among sirtuins in alveolar bone tissue. Based on micro-CT and CEJ-ABC distance, Sirt6Tg was observed to resist bone loss against ligature-induced periodontitis. Furthermore, the number of osteoclasts was significantly reduced in Sirt6Tg-ligated mice compared with control-ligated mice, although systemic inflammatory cytokines did not change. Consistent with this observation, we confirmed that bone loss was significantly reduced when MDL801, a Sirt6 activator, was included in the ligation mouse model. Our findings demonstrate that Sirt6 activation prevents bone loss against ligature-induced periodontitis. Thus, a Sirt6 activator may provide a new therapeutic approach for periodontitis.


Asunto(s)
Pérdida de Hueso Alveolar , Periodontitis , Sirtuinas , Ratones , Masculino , Animales , Ratones Endogámicos C57BL , Periodontitis/metabolismo , Inflamación/complicaciones , Pérdida de Hueso Alveolar/etiología , Pérdida de Hueso Alveolar/prevención & control , Osteoclastos/metabolismo , Modelos Animales de Enfermedad , Citocinas/metabolismo , Sirtuinas/genética
3.
J Korean Med Sci ; 36(50): e343, 2021 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-34962115

RESUMEN

As hospitals cater to elderly and vulnerable patients, a high mortality rate is expected if a coronavirus disease 2019 (COVID-19) outbreak occurs. Consequently, policies to prevent the spread of COVID-19 in hospital settings are essential. This study was conducted to investigate how effectively national and international guidelines provide recommendations for infection control issues in hospitals. After selecting important issues in infection control, we performed a systematic review and analysis of recommendations and guidelines for preventing COVID-19 transmission within medical institutions at national and international levels. We analyzed guidelines from the World Health Organization, Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, and Korea Disease Control and Prevention Agency. Recent guidelines do not provide specific solutions to infection control issues. Therefore, efforts need to be made to devise consistent advice and guidelines for COVID-19 control.


Asunto(s)
COVID-19/prevención & control , Control de Infecciones/métodos , Guías de Práctica Clínica como Asunto , SARS-CoV-2 , Personal de Salud , Humanos
4.
Int J Mol Sci ; 22(1)2021 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-33401545

RESUMEN

Poly(methyl methacralyate) (PMMA) has long been used in dentistry as a base polymer for dentures, and it is recently being used for the 3D printing of dental materials. Despite its many advantages, its susceptibility to microbial colonization remains to be overcome. In this study, the interface between 3D-printed PMMA specimens and oral salivary biofilm was studied following the addition of zwitterionic materials, 2-methacryloyloxyethyl phosphorylcholine (MPC) or sulfobetaine methacrylate (SB). A significant reduction in bacterial and biofilm adhesions was observed following the addition of MPC or SB, owing to their protein-repellent properties, and there were no significant differences between the two test materials. Although the mechanical properties of the tested materials were degraded, the statistical value of the reduction was minimal and all the properties fulfilled the requirements set by the International Standard, ISO 20795-2. Additionally, both the test materials maintained their resistance to biofilm when subjected to hydrothermal fatigue, with no further deterioration of the mechanical properties. Thus, novel 3D-printable PMMA incorporated with MPC or SB shows durable oral salivary biofilm resistance with maintenance of the physical and mechanical properties.


Asunto(s)
Materiales Biocompatibles/farmacología , Biopelículas/efectos de los fármacos , Resinas Compuestas/química , Materiales Dentales/farmacología , Boca/efectos de los fármacos , Polímeros/química , Impresión Tridimensional/instrumentación , Adhesión Bacteriana , Biopelículas/crecimiento & desarrollo , Humanos , Ensayo de Materiales , Metacrilatos/química , Boca/microbiología , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Streptococcus mutans/efectos de los fármacos , Streptococcus mutans/metabolismo
5.
Molecules ; 26(7)2021 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-33804968

RESUMEN

Gelatin, a natural polymer, provides excellent tissue compatibility for use in tissue rehabilitation. Bioactive glasses (BAG) offer superior capacity in stimulating a bioactive response but show high variability in uptake and solubility. To tackle these drawbacks, a combination of gelatin with BAG is proposed to form composites, which then offer a synergistic response. The cross-linked gelatin structure's mechanical properties are enhanced by the incorporation of the inorganic BAG, and the rate of BAG ionic supplementation responsible for bioactivity and regenerative potential is better controlled by a protective gelatin layer. Several studies have demonstrated the cellular benefits of these composites in different forms of functional modification such as doping with zinc or incorporation of zinc such as ions directly into the BAG matrix. This review presents a comprehensive perspective on the individual characteristics of BAG and gelatin, including the synthesis and mechanism of action. Further, adaptation of the composite into various applications for bone tissue engineering is discussed and future challenges are highlighted.


Asunto(s)
Regeneración Ósea/efectos de los fármacos , Huesos/metabolismo , Gelatina , Vidrio/química , Ingeniería de Tejidos , Andamios del Tejido/química , Zinc , Animales , Gelatina/química , Gelatina/farmacología , Humanos , Zinc/química , Zinc/farmacología
6.
Molecules ; 26(5)2021 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-33799919

RESUMEN

Herein, we investigated the surface characterization and biocompatibility of a denture-lining material containing Cnidium officinale extracts and its antifungal efficacy against Candida albicans. To achieve this, a denture-lining material containing various concentrations of C. officinale extract and a control group without C. officinale extract were prepared. The surface characterization and biocompatibility of the samples were investigated. In addition, the antifungal efficacy of the samples on C. albicans was investigated using spectrophotometric growth and a LIVE/DEAD assay. The results revealed that there was no significant difference between the biocompatibility of the experimental and control groups (p > 0.05). However, there was a significant difference between the antifungal efficiency of the denture material on C. albicans and that of the control group (p < 0.05), which was confirmed by the LIVE/DEAD assay. These results indicate the promising potential of the C. officinale extract-containing denture-lining material as an antifungal dental material.


Asunto(s)
Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , Cnidium/química , Alineadores Dentales , Extractos Vegetales/farmacología , Antifúngicos/química , Antifúngicos/toxicidad , Línea Celular , Color , Alineadores Dentales/microbiología , Fibroblastos/efectos de los fármacos , Humanos , Ensayo de Materiales , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/química , Extractos Vegetales/toxicidad , Propiedades de Superficie
7.
J Korean Med Sci ; 35(32): e297, 2020 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-32808513

RESUMEN

BACKGROUND: There is limited information describing the presenting characteristics and dynamic clinical changes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection diagnosed in the early phase of illness. This study is a case series of patients with coronavirus disease 2019 (COVID-19) admitted to 11 hospitals in Korea. METHODS: Patients with confirmed SARS-CoV-2 infection by positive polymerase chain reaction (PCR) testing of respiratory specimens by active surveillance that were finally discharged between February 20 and April 30, 2020 were included. Patients were classified into mild and non-mild groups on initial admission according to oxygen demand and Sequential Organ Failure Assessment score, and the mild group was followed up and subgrouped into non-aggravation and aggravation groups. RESULTS: A total of 161 patients with SARS-CoV2 infection were enrolled. Among the mild group of 136 patients, 11.7% of patients experienced clinical aggravation during hospitalization, but there was no initial clinical parameter on admission predicting their aggravation. Fever (odds ratio [OR], 4.56), thrombocytopenia (OR, 12.87), fever (OR, 27.22) and lactate dehydrogenase (LDH) > 300 U/L (OR, 18.35), and CRP > 1 mg/dL (OR, 11.31) significantly indicated aggravation in the 1st, 2nd, 3rd, and 4th 5-day periods, respectively. PCR positivity lasted for a median of 22 days and 32 days after the onset of illness in the non-aggravation and aggravation groups, respectively. CONCLUSION: Old age was associated with early severe presentation. Clinical aggravation among asymptomatic or mild patients could not be predicted initially but was heralded by fever and several laboratory markers during the clinical course.


Asunto(s)
Betacoronavirus , Infecciones por Coronavirus/diagnóstico , Neumonía Viral/diagnóstico , Adulto , Anciano , COVID-19 , Infecciones por Coronavirus/tratamiento farmacológico , Diagnóstico Precoz , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oxígeno/uso terapéutico , Pandemias , Neumonía Viral/tratamiento farmacológico , Reacción en Cadena en Tiempo Real de la Polimerasa , SARS-CoV-2 , Carga Viral
8.
J Korean Med Sci ; 33(50): e319, 2018 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-30534031

RESUMEN

The incidence of severe fever with thrombocytopenia syndrome (SFTS) has increased in Korea since a first report in 2013. We investigated whether SFTS existed before 2013 using real-time reverse transcription polymerase chain reaction and stored blood samples from febrile patients with thrombocytopenia. Four cases of SFTS were identified, with the earliest occurring in 2008.


Asunto(s)
Fiebre/etiología , Linfohistiocitosis Hemofagocítica/diagnóstico , Trombocitopenia/diagnóstico , Médula Ósea/patología , Ferritinas/sangre , Fiebre/diagnóstico , Humanos , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Linfohistiocitosis Hemofagocítica/complicaciones , Masculino , Persona de Mediana Edad , República de Corea , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Trombocitopenia/complicaciones , Adulto Joven
9.
Arch Virol ; 162(11): 3389-3396, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28779231

RESUMEN

Noroviruses (NoVs) are the major global source of acute gastroenteritis (AGE) outbreaks. To detect NoVs, real-time reverse transcription-quantitative PCR (RT-qPCR) assays have been widely employed since the first decade of the 21st century. We developed a redesigned probe, JJV1PM, for RT-qPCR assay detection of NoV genogroup (G) I strains. The new RT-qPCR assay using the JJV1PM-probe showed broader strain reactivity for 10 NoV GI genotypes, while the old method, using the JJV1PT-probe assay, detected only 7 NoV GI genotypes in a validation panel using human fecal specimens. The improved RT-qPCR assay was also successfully applied to water samples. The JJV1PM-probe assay identified 7 NoV GI genotypes, whereas the JJV1PT-probe assay detected only 2 NoV GI genotypes from water samples. Notably, groundwater-borne NoV GI strains detected by the improved JJV1PM-probe assay were associated with groundwater-borne AGE outbreaks in South Korea. The results of this study underscore the importance of the evaluation of RT-qPCR assays using recently circulating NoV strains prior to field application.


Asunto(s)
Norovirus/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Genotipo , Microbiología del Agua
10.
Antimicrob Agents Chemother ; 59(4): 2470-3, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25666156

RESUMEN

We conducted a retrospective cohort study to evaluate factors influencing tissue culture positivity in patients with pyogenic vertebral osteomyelitis exposed to antibiotics before diagnosis. Tissue culture was positive in 48.3% (28/58) of the patients, and the median antibiotic-free period was 1.5 days (range, 0.7 to 5.7 days). In a multivariate analysis, a higher C-reactive protein (CRP) level (adjusted odds ratio [aOR], 1.18; 95% confidence interval, 1.07 to 1.29) and open surgical biopsy (aOR, 6.33; 95% confidence interval, 1.12 to 35.86) were associated with tissue culture positivity.


Asunto(s)
Antibacterianos/uso terapéutico , Osteomielitis/microbiología , Enfermedades de la Columna Vertebral/microbiología , Anciano , Infecciones Bacterianas/tratamiento farmacológico , Biopsia , Proteína C-Reactiva/metabolismo , Estudios de Cohortes , Femenino , Fiebre/complicaciones , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Columna Vertebral/microbiología
11.
Antimicrob Agents Chemother ; 59(2): 811-7, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25403664

RESUMEN

Vancomycin is frequently inappropriately prescribed, especially as empirical treatment. The aim of this study was to evaluate (i) the amount of inappropriate continued empirical vancomycin use as a proportion of total vancomycin use and (ii) the risk factors associated with inappropriate continued empirical vancomycin use. We reviewed the medical records of adult patients who had been prescribed at least one dose of parenterally administered vancomycin between January and June 2012, in a single tertiary care hospital. When empirically prescribed vancomycin treatment was continued after 96 h without documentation of beta-lactam-resistant Gram-positive microorganisms in clinical specimens with significance, the continuation was considered inappropriate, and the amount used thereafter was considered inappropriately used. We identified risk factors associated with inappropriate continued empirical vancomycin use by multiple logistic regression. During the study period, the amount of parenterally administered vancomycin prescribed was 34.2 defined daily doses (DDDs)/1,000 patient-days (1,084 prescriptions for 971 patients). The amount of inappropriate continued empirical vancomycin use was 8.5 DDDs/1,000 patient-days, which represented 24.9% of the total parenterally administered vancomycin used (8.5/34.2 DDDs/1,000 patient-days). By multivariate analyses, inappropriate continued empirical vancomycin use was independently associated with the absence of any documented etiological organism (adjusted odds ratio [aOR], 1.60 [95% confidence interval {CI}, 1.06 to 2.41]) and suspected central nervous system (CNS) infections (aHR, 2.33 [95% CI, 1.20 to 4.50]). Higher Charlson's comorbidity index scores were inversely associated with inappropriate continued empirical vancomycin use (aHR, 0.90 [95% CI, 0.85 to 0.97]). Inappropriate continued empirical vancomycin use represented 24.9% of the total amount of vancomycin prescribed, which indicates room for improvement.


Asunto(s)
Antibacterianos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Vancomicina/farmacología , Femenino , Humanos , Modelos Logísticos , Masculino , Prevalencia , Estudios Retrospectivos , Factores de Riesgo
12.
BMC Infect Dis ; 15: 289, 2015 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-26209977

RESUMEN

BACKGROUND: Asymptomatic bacteriuria (ABU) is common and often leads to unnecessary antimicrobial use. Reducing antibiotic overuse for ABU is therefore an important issue for antimicrobial stewardship. We performed this study to investigate the appropriateness of ABU management and to evaluate physicians' knowledge and practice regarding ABU. METHODS: We reviewed all urine cultures of ≥10(5) cfu/mL of bacteria among inpatients in a 900-bed hospital in 2011. Each episode of bacteriuria was classified into ABU or urinary tract infection (UTI). ABU was defined as a positive urine culture (≥10(5) cfu/mL) without symptoms or signs suggesting UTI. In October 2012 a cross-sectional survey of resident physicians was undertaken using an anonymous, self-administered questionnaire. RESULTS: We identified 219 ABU cases among 1167 positive urine cultures, of which 70 (32.0 %) were inappropriately treated. Female gender, old age, pyuria, hematuria, and positive nitrite on urinalysis were associated with inappropriate ABU treatment in a multivariate analysis (P < 0.05). The response rate to the survey was 74.2 % (95/128). The mean knowledge score was 37.3 %, and 33.7 % of respondents were able to distinguish ABU from UTI, but less than half knew the indications for treating ABU. Even after ABU was correctly diagnosed, concerns about postoperative infections (38.6 %), UTI (9.1 %), and abnormal urinalysis (29.5 %) prevented proper management. About half of the respondents reported to prescribing antibiotics for ABU despite knowing they were not indicated. CONCLUSIONS: About one third of ABUs were inappropriately managed. Lack of knowledge and discrepancies between knowledge and practice, contributed to antimicrobial overuse for ABU. Our findings highlight the importance of developing interventions, including education, audit and feedback, to tackle the problem of inappropriate treatment of ABU.


Asunto(s)
Bacteriuria/epidemiología , Pautas de la Práctica en Medicina/estadística & datos numéricos , Infecciones Urinarias/epidemiología , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Bacteriuria/diagnóstico , Bacteriuria/tratamiento farmacológico , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , República de Corea/epidemiología , Estudios Retrospectivos , Encuestas y Cuestionarios , Atención Terciaria de Salud/estadística & datos numéricos , Urinálisis , Infecciones Urinarias/diagnóstico , Infecciones Urinarias/tratamiento farmacológico
13.
J Oral Maxillofac Surg ; 72(6): 1093.e1-11, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24709514

RESUMEN

PURPOSE: Distant migration associated with sinus lifting procedures has not been investigated. In the present study, a case of distant migration of graft material was observed, and the potential mechanisms of migration were analyzed using material analysis and in vivo experiments. MATERIALS AND METHODS: The migrated graft material was biphasic calcium phosphate-based alloplastic material (BCP), and its physical properties were compared with those of xenogenic material (Bio-Oss). The comparisons of the physical properties were performed using scanning electronic microscopic, x-ray diffraction, and Fourier-transform infrared absorbance spectra analysis. The comparative graft migration study was performed using the subcutaneous pocket model in rats (n = 10). The clinical case was analyzed by histologic section and energy dispersive x-ray (EDX) microanalysis. RESULTS: The observed diffraction patterns from the Bio-Oss revealed characteristic diffractions for the hydroxyapatite phase, and those from the BCP revealed additional diffractions that could be assigned to the tricalcium phosphate phase. In the animal model, the graft migration distances observed in the BCP group were significantly greater than those observed in the Bio-Oss group (P = .012). In the clinical case, the lymphatic vessels of the submandibular gland contained foreign materials that were morphologically similar to those of the maxillary sinus. EDX microanalysis revealed that the particles in the lymphatic vessels exhibited calcium concentrations that were approximately 200 times greater than those in the adjacent glandular tissue. CONCLUSIONS: In the present study, BCP-based sinus grafts had migrated into the submandibular glandular area by way of the lymphatic chain in the presented clinical case.


Asunto(s)
Sustitutos de Huesos/efectos adversos , Migración de Cuerpo Extraño/etiología , Elevación del Piso del Seno Maxilar/efectos adversos , Animales , Fenómenos Químicos , Tejido Conectivo/patología , Modelos Animales de Enfermedad , Microanálisis por Sonda Electrónica , Cuerpos Extraños/patología , Tejido de Granulación/patología , Humanos , Hidroxiapatitas/efectos adversos , Hidroxiapatitas/química , Linfadenitis/etiología , Vasos Linfáticos/patología , Masculino , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Minerales/efectos adversos , Minerales/química , Tamaño de la Partícula , Ratas , Espectroscopía Infrarroja por Transformada de Fourier , Infecciones Estafilocócicas/microbiología , Tejido Subcutáneo/microbiología , Tejido Subcutáneo/cirugía , Glándula Submandibular/patología , Difracción de Rayos X
14.
J Oral Maxillofac Surg ; 72(1): 53-60, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24331565

RESUMEN

PURPOSE: The objective of this study was to compare peri-implant bone formation among uncoated (UC), hydroxyapatite (HA), collagen plus HA (CH), and collagen, HA, plus bone morphogenetic protein-2 (BMP-2) implant groups. MATERIALS AND METHODS: Implants in the UC group had acid-etched surfaces. The surface coating was applied using the aerosol deposition method. The coated surfaces were examined by scanning electron microscopy, x-ray diffraction (XRD), and Fourier-transformed infrared absorption analysis. Subsequently, 6 implants from each group (total, 24 implants) were installed in the tibias of rabbits. The animals were sacrificed at 6 weeks after implant installation. Peri-implant bone formation and bone-to-implant contact (BIC) were measured in histologic sections. Significant differences among groups were evaluated using analysis of variance. RESULTS: Based on the measured XRD patterns, there was a characteristic HA phase (International Centre for Diffraction Data [ICDD], 086-0740) coated on the titanium (ICDD, 089-3725). Subsequent coating processes for collagen and BMP-2 did not display additional diffraction peaks, but maintained the diffraction patterns of the HA-coated titanium. The presence of collagen was verified by infrared absorption analysis. When comparing these modifications with UC surfaces, only the CH coating displayed significantly greater peri-implant bone formation and BIC (P = .003 and P < .001, respectively). Adding BMP-2 to the implant surface did not produce any advantage compared with the CH coating. CONCLUSIONS: In this study, the CH group displayed significantly greater new bone formation and BIC than the other groups. There was no significant difference among the other groups.


Asunto(s)
Proteína Morfogenética Ósea 2/química , Materiales Biocompatibles Revestidos/química , Colágeno Tipo I/química , Implantes Dentales , Diseño de Prótesis Dental , Durapatita/química , Osteogénesis/fisiología , Grabado Ácido Dental/métodos , Aerosoles , Animales , Materiales Dentales/química , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oseointegración/fisiología , Conejos , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Tibia/patología , Tibia/cirugía , Titanio/química , Difracción de Rayos X
15.
Adv Biol (Weinh) ; : e2400083, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38717792

RESUMEN

The regulation of complex energy metabolism is intricately linked to cellular energy demands. Caloric restriction (CR) plays a pivotal role in modulating the expression of genes associated with key metabolic pathways, including glycolysis, the tricarboxylic acid (TCA) cycle, and the glyoxylate cycle. In this study, the chronological lifespan (CLS) of 35 viable single-gene deletion mutants under both non-restricted and CR conditions, focusing on genes related to these metabolic pathways is evaluated. CR is found to increase CLS predominantly in mutants associated with the glycolysis and TCA cycle. However, this beneficial effect of CR is not observed in mutants of the glyoxylate cycle, particularly those lacking genes for critical enzymes like isocitrate lyase 1 (icl1Δ) and malate synthase 1 (mls1Δ). This analysis revealed an increase in isocitrate lyase activity, a key enzyme of the glyoxylate cycle, under CR, unlike the activity of isocitrate dehydrogenase, which remains unchanged and is specific to the TCA cycle. Interestingly, rapamycin, a compound known for extending lifespan, does not increase the activity of the glyoxylate cycle enzyme. This suggests that CR affects lifespan through a distinct metabolic mechanism.

16.
Nat Commun ; 15(1): 3586, 2024 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-38678023

RESUMEN

Anode-free (or lithium-metal-free) batteries with garnet-type solid-state electrolytes are considered a promising path in the development of safe and high-energy-density batteries. However, their practical implementation has been hindered by the internal strain that arises from the repeated plating and stripping of lithium metal at the interlayer between the solid electrolyte and negative electrode. Herein, we utilize the titanium nitrate nanotube architecture and a silver-carbon interlayer to mitigate the anisotropic stress caused by the recurring formation of lithium deposition layers during the cycling process. The mixed ionic-electronic conducting nature of the titanium nitrate nanotubes effectively accommodates the entry of reduced Li into its free volume space via interfacial diffusion creep, achieving near-strain-free operation with nearly tenfold volume suppressing capability compared to a conventional Cu anode counterpart during the lithiation process. Notably, the fabricated Li6.4La3Zr1.7Ta0.3O12 (LLZTO)-based initial-anode-free quasi-solid-state battery full cell, coupled with an ionic liquid catholyte infused high voltage LiNi0.33Co0.33Mn0.33O2-based cathode with an areal capacity of 3.2 mA cm-2, exhibits remarkable room temperature (25 °C) cyclability of over 600 cycles at 1 mA cm-2 with an average coulombic efficiency of 99.8%.

17.
Int J Syst Evol Microbiol ; 63(Pt 4): 1311-1316, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22798648

RESUMEN

Two strains of gram-negative, catalase- and oxidase-positive, coccus-shaped bacteria, designated NB88(T) and LNB004, were isolated from activated sludge in the Mae-san sewage treatment plant in South Korea. They were characterized in a polyphasic taxonomic study based on phenotypic, phylogenetic and genotypic approaches. Comparative 16S rRNA gene sequence analysis indicated that strains NB88(T) and LNB004 represented a novel subline within the genus Paracoccus in the family Rhodobacteraceae. According to 16S rRNA gene sequence comparisons, strains NB88(T) and LNB004 were indistinguishable and showed 94.5-97.6 % similarity to the type strains of other Paracoccus species. Strain NB88(T) exhibited relatively high levels of DNA hybridization (84±3.5 %) with LNB004 and low hybridization values (<40 %) with type strains of other Paracoccus species. Both strains showed chemotaxonomic characteristics typical of the genus Paracoccus, with Q-10 as the predominant respiratory quinone and C18 : 1ω7c as the major fatty acid, and both strains accumulated poly-ß-hydroxybutyrate granules. The DNA G+C contents of strains NB88(T) and LNB004 were 66.4 and 65.1 mol%, respectively. The polar lipid profiles of strains NB88(T) and LNB004 included major amounts of phosphatidylglycerol, phosphatidylcholine and an unknown aminolipid. The taxonomic position of strains NB88(T) and LNB004 was clarified by the low level of DNA-DNA hybridization with closely related strains and the strains could be distinguished from other recognized species by using biochemical tests and molecular genetic analysis. On the basis of their phenotypic and genotypic properties and their phylogenetic distinctiveness, strains NB88(T) and LNB004 should be classified in a novel species of the genus Paracoccus, for which the name Paracoccus limosus sp. nov. is proposed. The type strain is NB88(T) ( = KEMC 5401-184(T)  = JCM 17370(T)); strain LNB004 ( = KEMC 5401-001) is a reference strain.


Asunto(s)
Paracoccus/clasificación , Filogenia , Aguas del Alcantarillado/microbiología , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/genética , Ácidos Grasos/análisis , Hidroxibutiratos/metabolismo , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Paracoccus/genética , Paracoccus/aislamiento & purificación , Poliésteres/metabolismo , Quinonas/análisis , ARN Ribosómico 16S/genética , República de Corea , Análisis de Secuencia de ADN
18.
J Nanosci Nanotechnol ; 13(9): 6400-4, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24205669

RESUMEN

Improving the response time for polyimide (PI)-based capacitive humidity sensors is critical for real-time sensing. Multi-walled carbon nanotube (MWCNT) films were used to form the upper electrode of humidity sensor to realize an extremely short response times. MWCNT films were spray-deposited on a moisture-sensitive PI layer and subsequently patterned by oxygen plasma. Random-network MWCNT electrodes have a well-entangled and open porous structure that is almost impossible to obtain with conventional metal electrodes. Compared with porous metal electrode-based sensors as an upper electrode, the fabricated capacitive humidity sensors with MWCNT electrodes showed an exceptionally short response time of less than 2.5 s and a good linearity of 0.998. An analysis of the long-term (100 days) stability data revealed that the MWCNT electrode humidity sensors showed little drift even after 100 days aging, indicating that they are suitable for practical and reliable humidity measurements. These improvements in performance may stem from their interconnected microscopic porous structure, which is more accessible to water molecules through the conductive electrode.

19.
Polymers (Basel) ; 15(2)2023 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-36679178

RESUMEN

Poly (methyl methacrylate) (PMMA) is a commonly used denture material with poor antimicrobial effects. This study investigated the antimicrobial effects of PMMA-containing silver-phosphate glass. We fabricated a novel material comprising PMMA-containing silver-phosphate glass. Then, microhardness, flexural strength, and gloss unit were analyzed. Antimicrobial activity against Streptococcus mutans and Candida albicans was investigated. Colony-forming units were counted, and antimicrobial rates were measured. Biocompatibility tests were performed using a colorimetric MTT assay for evaluating cell metabolic activity. The microhardness, flexural strength, and gloss unit of the experimental groups (with silver-phosphate glass) were not significantly different from those of the control group (no silver-phosphate glass) (P > 0.05), which showed clinically valid values. With increasing proportions of silver-phosphate glass, the antimicrobial activity against the two microorganisms increased (P < 0.05). Furthermore, S. mutans showed more than 50% antimicrobial activity in 4%, 6%, and 8% experimental groups, C. albicans showed more than 50% antimicrobial activity in 6% and 8% groups, and a statistically significant difference in antimicrobial activity was observed compared to the control (P < 0.05). The cell viability of the experimental groups was not significantly different from that of the control group (P > 0.05). Both control and experimental groups showed approximately 100% cell viability. These results suggest that silver-phosphate glass is a promising antimicrobial material in dentistry.

20.
Materials (Basel) ; 16(13)2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37445067

RESUMEN

The biomechanical effects of dental tissue according to various dental crown materials were investigated using finite element analysis. Bone, prepared tooth, root canal, and periodontal ligament were modeled based on computed tomography. Depending on the characteristics of the crown material, it was classified into zirconia, hybrid ceramic, gold alloy, and acrylic resin. A loading force of 200 N was applied in the vertical direction to the occlusal surface of the crown, and analysis was performed under the condition that all interfaces were tied. The results demonstrate that the highest von Mises stress was shown in the prepared tooth of the acrylic resin model, which is a temporary prosthesis, and the pulpal pressure was also the highest. Additionally, among the final prosthesis, the highest stress was shown in the hybrid ceramic model prepared teeth. The properties of restoration materials can be a factor influencing the tooth structure. Thus, in order to make a correct decision when selecting a material for restorative treatment, it is necessary to understand, analyze, and evaluate the properties of these restoration materials.

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