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1.
BMC Oral Health ; 24(1): 775, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38987748

RESUMO

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.


Assuntos
Resinas Acrílicas , Antifúngicos , Candida albicans , Vidro , Teste de Materiais , Fosfatos , Estrôncio , Propriedades de Superfície , Candida albicans/efeitos dos fármacos , Resinas Acrílicas/química , Estrôncio/farmacologia , Estrôncio/química , Antifúngicos/farmacologia , Vidro/química , Fosfatos/farmacologia , Polimerização , Dureza , Resistência à Flexão , Humanos , Técnicas In Vitro
2.
Int J Mol Sci ; 24(13)2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37445896

RESUMO

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.


Assuntos
Perda do Osso Alveolar , Periodontite , Sirtuínas , Camundongos , Masculino , Animais , Camundongos Endogâmicos C57BL , Periodontite/metabolismo , Inflamação/complicações , Perda do Osso Alveolar/etiologia , Perda do Osso Alveolar/prevenção & controle , Osteoclastos/metabolismo , Modelos Animais de Doenças , Citocinas/metabolismo , Sirtuínas/genética
3.
J Korean Med Sci ; 36(50): e343, 2021 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-34962115

RESUMO

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.


Assuntos
COVID-19/prevenção & controle , Controle de Infecções/métodos , Guias de Prática Clínica como Assunto , SARS-CoV-2 , Pessoal de Saúde , Humanos
4.
Int J Mol Sci ; 22(1)2021 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-33401545

RESUMO

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.


Assuntos
Materiais Biocompatíveis/farmacologia , Biofilmes/efeitos dos fármacos , Resinas Compostas/química , Materiais Dentários/farmacologia , Boca/efeitos dos fármacos , Polímeros/química , Impressão Tridimensional/instrumentação , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Humanos , Teste de Materiais , Metacrilatos/química , Boca/microbiologia , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/metabolismo
5.
Molecules ; 26(7)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804968

RESUMO

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.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/metabolismo , Gelatina , Vidro/química , Engenharia Tecidual , Alicerces Teciduais/química , Zinco , Animais , Gelatina/química , Gelatina/farmacologia , Humanos , Zinco/química , Zinco/farmacologia
6.
Molecules ; 26(5)2021 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-33799919

RESUMO

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.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Cnidium/química , Reembasadores de Dentadura , Extratos Vegetais/farmacologia , Antifúngicos/química , Antifúngicos/toxicidade , Linhagem Celular , Cor , Reembasadores de Dentadura/microbiologia , Fibroblastos/efeitos dos fármacos , Humanos , Teste de Materiais , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Extratos Vegetais/toxicidade , Propriedades de Superfície
7.
J Korean Med Sci ; 35(32): e297, 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32808513

RESUMO

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.


Assuntos
Betacoronavirus , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Adulto , Idoso , COVID-19 , Infecções por Coronavirus/tratamento farmacológico , Diagnóstico Precoce , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/uso terapêutico , Pandemias , Pneumonia Viral/tratamento farmacológico , Reação em Cadeia da Polimerase em Tempo Real , SARS-CoV-2 , Carga Viral
8.
J Korean Med Sci ; 33(50): e319, 2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30534031

RESUMO

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.


Assuntos
Febre/etiologia , Linfo-Histiocitose Hemofagocítica/diagnóstico , Trombocitopenia/diagnóstico , Medula Óssea/patologia , Ferritinas/sangue , Febre/diagnóstico , Humanos , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Linfo-Histiocitose Hemofagocítica/complicações , Masculino , Pessoa de Meia-Idade , República da Coreia , Estudos Retrospectivos , Índice de Gravidade de Doença , Trombocitopenia/complicações , Adulto Jovem
9.
Arch Virol ; 162(11): 3389-3396, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28779231

RESUMO

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.


Assuntos
Norovirus/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Genótipo , Microbiologia da Água
10.
Antimicrob Agents Chemother ; 59(4): 2470-3, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25666156

RESUMO

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.


Assuntos
Antibacterianos/uso terapêutico , Osteomielite/microbiologia , Doenças da Coluna Vertebral/microbiologia , Idoso , Infecções Bacterianas/tratamento farmacológico , Biópsia , Proteína C-Reativa/metabolismo , Estudos de Coortes , Feminino , Febre/complicações , Humanos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Coluna Vertebral/microbiologia
11.
Antimicrob Agents Chemother ; 59(2): 811-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25403664

RESUMO

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.


Assuntos
Antibacterianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Vancomicina/farmacologia , Feminino , Humanos , Modelos Logísticos , Masculino , Prevalência , Estudos Retrospectivos , Fatores de Risco
12.
BMC Infect Dis ; 15: 289, 2015 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-26209977

RESUMO

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.


Assuntos
Bacteriúria/epidemiologia , Padrões de Prática Médica/estatística & dados numéricos , Infecções Urinárias/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/uso terapêutico , Bacteriúria/diagnóstico , Bacteriúria/tratamento farmacológico , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , República da Coreia/epidemiologia , Estudos Retrospectivos , Inquéritos e Questionários , Atenção Terciária à Saúde/estatística & dados numéricos , Urinálise , Infecções Urinárias/diagnóstico , Infecções Urinárias/tratamento farmacológico
13.
J Oral Maxillofac Surg ; 72(6): 1093.e1-11, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24709514

RESUMO

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.


Assuntos
Substitutos Ósseos/efeitos adversos , Migração de Corpo Estranho/etiologia , Levantamento do Assoalho do Seio Maxilar/efeitos adversos , Animais , Fenômenos Químicos , Tecido Conjuntivo/patologia , Modelos Animais de Doenças , Microanálise por Sonda Eletrônica , Corpos Estranhos/patologia , Tecido de Granulação/patologia , Humanos , Hidroxiapatitas/efeitos adversos , Hidroxiapatitas/química , Linfadenite/etiologia , Vasos Linfáticos/patologia , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Minerais/efeitos adversos , Minerais/química , Tamanho da Partícula , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier , Infecções Estafilocócicas/microbiologia , Tela Subcutânea/microbiologia , Tela Subcutânea/cirurgia , Glândula Submandibular/patologia , Difração de Raios X
14.
J Oral Maxillofac Surg ; 72(1): 53-60, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24331565

RESUMO

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.


Assuntos
Proteína Morfogenética Óssea 2/química , Materiais Revestidos Biocompatíveis/química , Colágeno Tipo I/química , Implantes Dentários , Planejamento de Prótese Dentária , Durapatita/química , Osteogênese/fisiologia , Condicionamento Ácido do Dente/métodos , Aerossóis , Animais , Materiais Dentários/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Osseointegração/fisiologia , Coelhos , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Tíbia/patologia , Tíbia/cirurgia , Titânio/química , Difração de Raios X
15.
Adv Biol (Weinh) ; : e2400083, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38717792

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-38678023

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-22798648

RESUMO

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.


Assuntos
Paracoccus/classificação , Filogenia , Esgotos/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/análise , Hidroxibutiratos/metabolismo , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Paracoccus/genética , Paracoccus/isolamento & purificação , Poliésteres/metabolismo , Quinonas/análise , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA
18.
J Nanosci Nanotechnol ; 13(9): 6400-4, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24205669

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-36679178

RESUMO

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.
Artigo em Inglês | MEDLINE | ID: mdl-37445067

RESUMO

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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