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1.
BMC Med Imaging ; 23(1): 109, 2023 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-37596563

RESUMO

BACKGROUND: Dental film mounting is an essential but time-consuming task in dental radiography, with manual methods often prone to errors. This study aims to develop a deep learning (DL) model for accurate automated classification and mounting of both intraoral and extraoral dental radiography. METHOD: The present study employed a total of 22,334 intraoral images and 1,035 extraoral images to train the model. The performance of the model was tested on an independent internal dataset and two external datasets from different institutes. Images were categorized into 32 tooth areas. The VGG-16, ResNet-18, and ResNet-101 architectures were used for pretraining, with the ResNet-101 ultimately being chosen as the final trained model. The model's performance was evaluated using metrics of accuracy, precision, recall, and F1 score. Additionally, we evaluated the influence of misalignment on the model's accuracy and time efficiency. RESULTS: The ResNet-101 model outperformed VGG-16 and ResNet-18 models, achieving the highest accuracy of 0.976, precision of 0.969, recall of 0.984, and F1-score of 0.977 (p < 0.05). For intraoral images, the overall accuracy remained consistent across both internal and external datasets, ranging from 0.963 to 0.972, without significant differences (p = 0.348). For extraoral images, the accuracy consistently achieved the highest value of 1 across all institutes. The model's accuracy decreased as the tilt angle of the X-ray film increased. The model achieved the highest accuracy of 0.981 with correctly aligned films, while the lowest accuracy of 0.937 was observed for films exhibiting severe misalignment of ± 15° (p < 0.001). The average time required for the tasks of image rotation and classification for each image was 0.17 s, which was significantly faster than that of the manual process, which required 1.2 s (p < 0.001). CONCLUSION: This study demonstrated the potential of DL-based models in automating dental film mounting with high accuracy and efficiency. The proper alignment of X-ray films is crucial for accurate classification by the model.


Assuntos
Aprendizado Profundo , Humanos , Radiografia Dentária
2.
Anal Chem ; 94(26): 9472-9480, 2022 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-35737371

RESUMO

Green analytical chemistry aims at developing analytical methods with minimum use and generation of hazardous substances for the protection of human health and the environment. To address this need, a green analytical protocol has been developed for the analysis of anionic compounds integrating electromembrane extraction (EME), dual-channel nanoelectrospray ionization (nanoESI), and a miniature mass spectrometer. Haloacetic acids (HAAs) have attracted considerable public concern due to their adverse effects on human health and were selected as model analytes for method development. A flat membrane EME device was developed and assembled in-house. Optimization of fundamental operational parameters was performed using single-factor test and response surface methodology. Both the EME acceptor phase and an imidazolium-based dicationic ionic liquid (DIL), 1,1-bis(3-methylimidazolium-1-yl) butylene difluoride (C4(MIM)2F2), were subjected to dual-channel nanoESI and miniature mass spectrometry analysis based on a charge inversion strategy, where positively charged complexes were formed. Enhancement in signal intensity by as much as 2 magnitudes was achieved in the positive-ion mode compared to the negative-ion mode in the absence of the dicationic ion-pairing agent. The developed protocol was validated, obtaining good recoveries ranging from 82.7 to 109.9% and satisfactory sensitivity with limits of detection (LODs) and quantitation (LOQs) in the ranges of 1-5 and 2-10 µg/L, respectively. The greenness of the analytical procedure was assessed with a calculated score of 0.71, indicating a high degree of greenness. The developed method was applied to the analysis of real environmental or municipal water samples (n = 16), exhibiting appealing potential for outside-the-laboratory applications.


Assuntos
Líquidos Iônicos , Ácidos , Humanos , Limite de Detecção , Espectrometria de Massas , Membranas Artificiais
3.
Biomacromolecules ; 23(3): 1251-1258, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-35084834

RESUMO

Diabetic patients with type 1 or advanced type 2 stages need timely and precise insulin injection to regulate the daily blood glucose levels (BGLs). Otherwise, risks of serious or even deadly diabetes-associated complications occur. To achieve prolonged glucose regulation and low hypoglycemia risks, a novel on-demand glucose-responsive glycopolymer system was constructed for insulin delivery, which was self-assembled into nanoparticles by dynamic covalent bonds between two polymers: fluorophenylboronic acid-grafted polymer (poly-F) and polyol polymer (poly-G). Insulin was loaded during the assembly process. The nanoparticles showed excellent glucose responsiveness in vitro, with controlled insulin release at different glucose concentrations. In vivo treatment on type 1 diabetic mice showed prolonged BGL regulation and lower hypoglycemia risks. The mild preparation of the nanoparticles and outstanding glucose control shed light on the optional diabetic treatment for further clinical use.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Hipoglicemia , Nanopartículas , Animais , Glicemia , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Glucose/química , Humanos , Hipoglicemia/induzido quimicamente , Hipoglicemia/tratamento farmacológico , Insulina , Camundongos , Nanopartículas/química , Polímeros/química
4.
Proc Natl Acad Sci U S A ; 116(20): 9931-9940, 2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-31036651

RESUMO

The long-standing view that Mesozoic mammaliaforms living in dinosaur-dominated ecosystems were ecologically constrained to small size and insectivory has been challenged by astonishing fossil discoveries over the last three decades. By studying these well-preserved early mammaliaform specimens, paleontologists now agree that mammaliaforms underwent ecomorphological diversification during the Mesozoic Era. This implies that Mesozoic mammaliaform communities had ecological structure and breadth that were comparable to today's small-bodied mammalian communities. However, this hypothesis remains untested in part because the primary focus of most studies is on individual taxa. Here, we present a study quantifying the ecological structure of Mesozoic mammaliaform communities with the aim of identifying evolutionary and ecological drivers that influenced the deep-time assembly of small-bodied mammaliaform communities. We used body size, dietary preference, and locomotor mode to establish the ecospace occupation of 98 extant, small-bodied mammalian communities from diverse biomes around the world. We calculated ecological disparity and ecological richness to measure the magnitude of ecological differences among species in a community and the number of different eco-cells occupied by species of a community, respectively. This modern dataset served as a reference for analyzing five exceptionally preserved, extinct mammaliaform communities (two Jurassic, two Cretaceous, one Eocene) from Konservat-Lagerstätten. Our results indicate that the interplay of at least three factors, namely the evolution of the tribosphenic molar, the ecological rise of angiosperms, and potential competition with other vertebrates, may have been critical in shaping the ecological structure of small-bodied mammaliaform communities through time.


Assuntos
Evolução Biológica , Ecossistema , Fósseis , Magnoliopsida , Mamíferos , Animais , Tamanho Corporal , Dieta , Locomoção , Dente Molar , Paleodontologia
5.
AAPS PharmSciTech ; 23(8): 285, 2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36258152

RESUMO

Breast cancer metastasis is an important cause of death in patients with breast cancer and is closely related to circulating tumor cells (CTCs) and the metastatic microenvironment. As the most infiltrating immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs), which highly express sialic acid (SA) receptor (Siglec-1), are closely linked to tumor progression and metastasis. Furthermore, the surface of CTCs also highly expressed receptor (Selectin) for SA. A targeting ligand (SA-CH), composed of SA and cholesterol, was synthesized and modified on the surface of epirubicin (EPI)-loaded liposomes (EPI-SL) as an effective targeting delivery system. Liposomes were evaluated for characteristics, stability, in vitro release, cytotoxicity, cellular uptake, pharmacokinetics, tumor targeting, and pharmacodynamics. In vivo and in vitro experiments showed that EPI-SL enhanced EPI uptake by TAMs. In addition, cellular experiments showed that EPI-SL could also enhance the uptake of EPI by 4T1 cells, resulting in cytotoxicity second only to that of EPI solution. Pharmacodynamic experiments have shown that EPI-SL has optimal tumor inhibition with minimal toxicity, which can be ascribed to the fact that EPI-SL can deliver drugs to tumor based on TAMs and regulate TME through the depletion of TAMs. Our study demonstrated the significant potential of SA-modified liposomes in antitumor metastasis. Schematic diagram of the role of SA-CH modified EPI-loaded liposomes in the model of breast cancer metastasis.


Assuntos
Neoplasias da Mama , Lipossomos , Humanos , Feminino , Epirubicina/farmacocinética , Ácido N-Acetilneuramínico , Neoplasias da Mama/tratamento farmacológico , Macrófagos Associados a Tumor , Lectina 1 Semelhante a Ig de Ligação ao Ácido Siálico , Ligantes , Linhagem Celular Tumoral , Imunoterapia , Colesterol , Microambiente Tumoral , Melanoma Maligno Cutâneo
6.
Bull Environ Contam Toxicol ; 108(5): 867-877, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35039887

RESUMO

Microplastics are easily consumed by marine animals, thereby entering the food chain and endangering animal health. However, there are few studies focusing on the effects of microplastics in mangrove sediments on microbial communities. In order to study the influence of microplastics on microorganisms, microplastics and microorganisms were extracted from Zhanjiang (Guangdong Province, China) mangrove sediments and analyzed. The results showed that there were differences in Shannon and Simpson indices of the microbial community in microplastics (p < 0.05), and there were also differences between JG30_KF_CM45 and Natranaerovirga at the genus level, indicating that microplastics may affect the diversity and composition of microorganisms in sediments. In addition, FAPROTAX function prediction analysis showed that microplastics may affect the nitrification of microbial communities. The results from this study indicate that microplastics affected the diversity and richness of microorganisms in mangrove sediments, which provides an experimental basis for the relationship between microplastics and microorganisms.


Assuntos
Microbiota , Microplásticos , Animais , China , Sedimentos Geológicos , Nitrificação , Plásticos/toxicidade , Áreas Alagadas
7.
Angew Chem Int Ed Engl ; 61(14): e202117195, 2022 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-35106884

RESUMO

Organism-inspired hollow structures are attracting increasing interest for the construction of various bionic functional hollow materials. Next-generation self-evolution hollow materials tend to combine simple synthesis, high mechanical strength, and regular shape. In this study, we designed and synthesized a novel dry-network polythiourethane thermoset with excellent mechanical performance. The polymer film could evolve into a neat and well-organized object with a macroscopic hollow interior structure after being immersed in an aqueous NaOH solution. The self-evolution hollow structure originated from a hydrogen-bonded polymer network, which was later transformed into a network bearing both hydrogen bonds and ionic bonds. The swelling and thickness growth of this material could be controlled by the NaOH concentration and the immersion time. This unique self-evolution behavior was further utilized to produce a series of macroscopic 3D hollow-containing molds, which could be potentially applied in the production of smart materials.


Assuntos
Hidrogênio , Polímeros , Ligação de Hidrogênio , Polímeros/química , Hidróxido de Sódio , Água
8.
J Clin Periodontol ; 48(9): 1165-1188, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34101223

RESUMO

AIM: Up-to-date epidemiological studies on the global burden of severe periodontitis is scarce. This study aimed to present the latest estimates for prevalence of severe periodontitis from 1990 to 2019, by region, age, and level of socio-demographic development. MATERIALS AND METHODS: Estimates from the Global Burden of Disease study 2019 were used to investigate burden and trends of prevalence of severe periodontitis and its association with socio-demographic development at global, regional, and national level. Decomposition analysis was performed to explore the contribution of demographic and epidemiological factors to the evolving burden of severe periodontitis. RESULTS: In 2019, there were 1.1 billion (95% uncertainty interval: 0.8-1.4 billion) prevalent cases of severe periodontitis globally. From 1990 to 2019, age-standardized prevalence rate of severe periodontitis increased by 8.44% (6.62%-10.59%) worldwide. Prevalence of severe periodontitis is higher among less developed countries/regions. Global population growth accounted for 67.9% of the increase in the number of prevalent cases of severe periodontitis from 1990 to 2019. CONCLUSIONS: The global burden of severe periodontitis has been substantial and increasing over the past three decades. Upstream policy changes are urgently needed to address the global public health challenge of severe periodontitis.


Assuntos
Carga Global da Doença , Periodontite , Saúde Global , Humanos , Incidência , Periodontite/epidemiologia , Prevalência , Anos de Vida Ajustados por Qualidade de Vida
9.
J Nanosci Nanotechnol ; 19(9): 5774-5782, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30961738

RESUMO

In this work, we investigated the influence of different concentrations of silver 2-ethylhexanoate on the synthesis and characteristics of silver nanoparticles (AgNPs) in resin matrix, as well as the antibacterial performance, mechanical properties and biocompatibility of the silver containing resin matrix, in order to provide a scientific basis for the application of AgNPs in restoration resins. The concentration of silver salt in resin matrix was set ranging from 0.05 wt% to 0.30 wt%. AgNPs were successfully synthesized in resin matrix by reducing silver ions in situ through photoinitiation. The results demonstrated that silver salt with low concentrations (≤0.20 wt%) had little influence on the degree of conversion, Knoop hardness and cell viability of silver resin matrix. However, silver salt with low concentrations (≤0.15 wt%) had little antibacterial activities against Streptococcus mutans. Therefore, it suggested that 0.20 wt% was a proper concentration for silver salt to be added into resin matrix, since silver salt at this concentration could exert a significantly antimicrobial activity without compromising the mechanical properties and biocompatibility of resin matrix.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos/farmacologia , Teste de Materiais , Resinas Sintéticas , Prata/farmacologia , Streptococcus mutans
10.
J Oral Maxillofac Surg ; 77(5): 920-931, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30682325

RESUMO

PURPOSE: Supernumerary teeth (SNTs) are teeth or tooth-like structures that have erupted or might erupt in addition to the 20 primary or 32 permanent teeth. The simultaneous presentation of multiple SNTs, syndrome-related multiple SNTs, SNTs inside the maxillary sinus and treatment outcomes were analyzed to develop improved diagnosis and management plans. PATIENTS AND METHODS: This retrospective study reviewed the medical records of National Cheng Kung University Hospital patients who had undergone surgical intervention with general anesthesia between February 2014 and September 2018; analyzed panoramic radiographs and cone beam computed tomography scans of their multiple SNTs; and used descriptive statistics to discuss treatments and relative complications, especially of unusual SNTs. RESULTS: The records of 165 patients (127 male and 38 female patients; mean age, 12.4 years) with 241 SNTs (120 patients had 1 SNT, 35 had 2 SNTs, 3 had 3 SNTs, 2 had 4 SNTs, 2 had 5 SNTs, 2 had 6 SNTs, and 1 had 12 SNTs) were reviewed. There were 185 SNTs in the maxilla and 56 in the mandible; 153 were mesiodens and 115 were inverted; 142 were asymptomatic and 137 were conical; and 228 were fully impacted and 210 were partial roots. Two patients had SNTs inside the maxillary sinus, and one had 5 SNTs and Marfan syndrome. Two patients had postoperative lip or chin paresthesia, and two had postoperative sinusitis. CONCLUSIONS: Patient demographic variables provided useful epidemiologic information. We recommend panoramic radiographs or cone beam computed tomography for managing patients with possible multiple SNTs and for extracting SNTs.


Assuntos
Dente Supranumerário , Criança , Feminino , Humanos , Masculino , Maxila , Estudos Retrospectivos , Dente Impactado , Resultado do Tratamento
11.
Biochem Biophys Res Commun ; 503(3): 2040-2046, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30086885

RESUMO

Periodontitis, a chronic infectious disease induced by microbial biofilm, is one of the most common diseases worldwide. Scaling and root planning (SRP) has always been recognized as the typical treatment. However, the therapeutic efficiency is often limited due to the intraoperative bleeding and the limitations of instruments. Non-thermal atmospheric plasma (NTP) appears to be a potential tool for periodontitis due to its promising biofilm degradation and decontamination effects. In this study, we investigated the role of NTP, as an adjuvant approach for the treatment of ligature-induced periodontitis in rats. Herein we showed that SRP or SRP-NTP application attenuated the periodontitis-induced alveolar bone loss, reflected by the increased BV/TV value and the decreased CEJ-AB distance, which might be related to the lower detection rate of periodontal pathogen in SRP and SRP-NTP groups. Besides, SRP-NTP rats showed less bone loss and lower CEJ-AB distance than that of SRP group at 30d post treatment, indicating a more comprehensive and long-lasting effect of SRP-NTP. A remarkable decrease of osteoclast number and lower expression of RANKL was also detected in SRP-NTP rats. In addition, expression of inflammatory-related cytokines such as TNF-α and IL-1ß decreased significantly in SRP-NTP group, while IL-10 level increased substantially. These results together illustrated that a combination of SRP and NTP treatment was an effective way to prevent periodontitis progress, which reduced alveolar bone loss and promoted periodontium restoration in ligature-induced periodontitis rats. In conclusion, non-thermal plasma treatment may be considered as a feasible and effective supplementary approach to control periodontitis.


Assuntos
Perda do Osso Alveolar/tratamento farmacológico , Periodontite/tratamento farmacológico , Gases em Plasma/uso terapêutico , Animais , Quimioterapia Combinada , Masculino , Ratos , Ratos Sprague-Dawley
12.
J Oral Maxillofac Surg ; 76(3): 503.e1-503.e8, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29125931

RESUMO

PURPOSE: We propose a 2-stage orthodontic lower third molar extraction procedure to reduce iatrogenic inferior alveolar nerve injury. We tested our hypothesis that there are factors that can predict both dislodgement of the root portion and limited traction distances. PATIENTS AND METHODS: Fifteen patients (mean age, 25.7 years; age range, 17 to 65 years) with 20 lower third molars were enrolled. Panoramic films and cone beam computed tomography were analyzed. Dislodgement of the root portion, traction distance, duration of the orthodontic phase, and postoperative complications were documented. The predictive factors were analyzed and discussed. RESULTS: Three teeth had dislodgements of the root portion. The mean traction duration was 59.2 days (range, 33 to 77 days), and the mean traction distance was 2.60 mm (range, 0.27 to 5.20 mm). Root apex cortical bone indentation and root curvature were significantly associated with traction distance. Pulpitis symptoms were documented in 1 tooth, and no postoperative nerve disturbances occurred. CONCLUSIONS: Our proposed 2-stage orthodontic lower third molar extraction procedure reduced iatrogenic inferior alveolar nerve injury. Cortical bone indentation and root curvature predicted dislodgement of the root portion and limited traction distances.


Assuntos
Dente Serotino/cirurgia , Extração Dentária/métodos , Adolescente , Adulto , Idoso , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dente Serotino/diagnóstico por imagem , Avaliação de Processos e Resultados em Cuidados de Saúde , Radiografia Panorâmica , Extração Dentária/efeitos adversos , Resultado do Tratamento , Traumatismos do Nervo Trigêmeo/prevenção & controle , Adulto Jovem
13.
Ecotoxicol Environ Saf ; 158: 293-299, 2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-29715634

RESUMO

Fenbuconazole (FBZ), a triazole-containing fungicide, is widely used in agriculture and horticulture. In the present study, the development and cardiac functioning were observed and determined in zebrafish embryos exposed to FBZ at 5, 50 and 500 ng/L nominal concentrations for 72 h. The results showed that 500 ng/L FBZ significantly increased pericardial edema rate, spine curvature rate, disturbed cardiac function, and led a shortened lower jaw. The transcription of genes such as tbx5, nkx2.5, tnnt2, gata4, bmp2b, myl7 was altered, which might be responsible for the cardiac developmental and functioning defects in the larvae. The deformation in bone development might be related with the impaired transcription levels of shh and bmp2b. The transcription of cyp26a1 (encoding retinoic acid metabolism enzyme) was significantly up-regulated in the 500 ng/L group, which might be a reason causing the teratogenic effect of FBZ. These results suggest that FBZ could have toxic effects on embryonic development, which should be considered in the risk evaluation of FBZ application.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Nitrilas/toxicidade , Triazóis/toxicidade , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/embriologia , Animais , Proteína Morfogenética Óssea 2/genética , Proteína Morfogenética Óssea 2/metabolismo , Relação Dose-Resposta a Droga , Embrião não Mamífero/metabolismo , Desenvolvimento Embrionário/efeitos dos fármacos , Feminino , Fatores de Transcrição GATA/genética , Fatores de Transcrição GATA/metabolismo , Coração/efeitos dos fármacos , Coração/embriologia , Proteína Homeobox Nkx-2.5/genética , Proteína Homeobox Nkx-2.5/metabolismo , Larva/efeitos dos fármacos , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/embriologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Troponina T/genética , Troponina T/metabolismo , Regulação para Cima , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismo
14.
Antimicrob Agents Chemother ; 59(12): 7308-15, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26369955

RESUMO

Staphylococcus aureus commonly infects medical implants or devices, with devastating consequences for the patient. The infection begins with bacterial attachment to the device, followed by bacterial multiplication over the surface of the device, generating an adherent sheet of bacteria known as a biofilm. Biofilms resist antimicrobial therapy and promote persistent infection, making management difficult to futile. Infections might be prevented by engineering the surface of the device to discourage bacterial attachment and multiplication; however, progress in this area has been limited. We have developed a novel nanoscale plasma coating technology to inhibit the formation of Staphylococcus aureus biofilms. We used monomeric trimethylsilane (TMS) and oxygen to coat the surfaces of silicone rubber, a material often used in the fabrication of implantable medical devices. By quantitative and qualitative analysis, the TMS/O2 coating significantly decreased the in vitro formation of S. aureus biofilms; it also significantly decreased in vivo biofilm formation in a mouse model of foreign-body infection. Further analysis demonstrated TMS/O2 coating significantly changed the protein adsorption, which could lead to reduced bacterial adhesion and biofilm formation. These results suggest that TMS/O2 coating can be used to effectively prevent medical implant-related infections.


Assuntos
Biofilmes/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Corpos Estranhos/prevenção & controle , Gases em Plasma/química , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Animais , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Materiais Revestidos Biocompatíveis/síntese química , Feminino , Fibrinogênio/antagonistas & inibidores , Fibrinogênio/química , Fibronectinas/antagonistas & inibidores , Fibronectinas/química , Corpos Estranhos/microbiologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Oxigênio/química , Próteses e Implantes/microbiologia , Ligação Proteica/efeitos dos fármacos , Albumina Sérica/antagonistas & inibidores , Albumina Sérica/química , Elastômeros de Silicone/química , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/fisiologia , Compostos de Trimetilsilil/química
15.
Langmuir ; 31(23): 6546-53, 2015 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-26010012

RESUMO

A metal-directed assembling approach has been developed to encapsulate hydrogenase (H2ase) within a layer-by-layer (LBL) multilayer of carbon nanotube polyelectrolyte (MWNT-PVPMe), which showed efficient biocatalytic oxidation of H2 gas. The MWNT-PVPMe was prepared via a diazonium process and addition reactions with poly(4-vinylpyridine) (PVP) and methyl iodide (MeI). The covalently attached polymers and organic substituents in the polyelectrolyte comprised 60-70% of the total weight. The polyelectrolyte was then used as a substrate for H2ase binding to produce MWNT-PVPMe@H2ase bionanocomposites. X-ray photoelectron spectra revealed that the bionanocomposites included the elements of Br, S, C, N, O, I, Fe, and Ni, which confirmed that they were composed of MWNT-PVPMe and H2ase. Field emission transmission electron microscope images revealed that the H2ase was adsorbed on the surface of MWNT-PVPMe with the domains ranging from 20 to 40 nm. Further, with the use of the bionanocomposites as nanolinkers and Na2PdCl4 as connectors, the (Pd/MWNT-PVPMe@H2ase)n multilayers were constructed on the quartz and gold substrate surfaces by the Pd(II)-directed LBL assembling technique. Finally, the as-prepared LBL multilayers were used as heterogeneous catalysts for hydrogen oxidation with methyl viologen (MV(2+)) as an electron carrier. The dynamic processes for the reversible color change between blue-colored MV(+) and colorless MV(2+) (catalyzed by the LBL multilayers) were video recorded, which confirmed that the H2ase encapsulated within the present LBL multilayers was of much stronger stability and higher biocatalytic activity of H2 oxidation resulting in potential applications for the development of H2 biosensors and fuel cells.


Assuntos
Hidrogênio/química , Hidrogenase/química , Nanocompostos/química , Nanotubos de Carbono/química , Paládio/química , Adsorção , Biocatálise , Cátions Bivalentes , Composição de Medicamentos , Hidrocarbonetos Iodados/química , Oxirredução , Paraquat/química , Polivinil/química , Propriedades de Superfície
16.
Am J Dent ; 27(2): 84-90, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25000666

RESUMO

PURPOSE: To study the plasma treatment effects on deactivation of oral bacteria seeded on a tooth enamel analogue. METHODS: A non-thermal atmospheric pressure argon plasma brush was used to treat two different Gram-positive oral bacteria including Lactobacillus acidophilus (L. acidophilus) and Streptococcus mutans (S. mutans). The bacteria were seeded on hydroxyapatite (HA) disks used as tooth enamel analogue with three initial bacterial seeding concentrations: a low inoculum concentration between 2.1 x 10(8) and 2.4 x 10(8) cfu/mL, a medium inoculum concentration between 9.8x10(8) and 2.4 x 10(9) cfu/mL, and a high inoculum concentration between 1.7 x 10(10) and 3.5 x 10(10) cfu/mL. The bacterial survivability upon plasma exposure was examined in terms of plasma exposure time and oxygen addition into the plasmas. SEM was performed to examine bacterial morphological changes after plasma exposure. RESULTS: The experimental data indicated that a 13-second plasma exposure time completely killed all the bacteria when initial bacterial seeding density on HA surfaces was less than 6.9 x 10(6) cfu/cm2 for L. acidophilus and 1.7 x 10(7) cfu/cm2 for S. mutans, which resulted from low initial seeding inoculum concentration between 2.1 x 10(8) and 2.4 x 10(8) cfu/mL. Plasma exposure of the bacteria at higher initial bacterial seeding density obtained with high initial seeding inoculum concentration, however, only resulted in approximately 1.5 to 2 log reduction and approximately 2 to 2.5 log reduction for L. acidophilus and S. mutans, respectively. It was also noted that oxygen addition into the argon plasma brush did not affect the plasma deactivation effectiveness. SEM images showed that plasma deactivation mainly occurred with the top layer bacteria, while shadowing effects from the resulting bacterial debris reduced the plasma deactivation of the underlying bacteria.


Assuntos
Esmalte Dentário/microbiologia , Durapatita/química , Lactobacillus acidophilus/efeitos dos fármacos , Gases em Plasma/uso terapêutico , Streptococcus mutans/efeitos dos fármacos , Carga Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Humanos , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Oxigênio/farmacologia , Ozônio/farmacologia , Fatores de Tempo
17.
J Environ Manage ; 144: 88-92, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24929499

RESUMO

Stable nanoscale zero-valent iron (NZVI) particles have been developed to remediate chlorinated compounds. The degradation kinetics and efficiency of trichloroethylene (TCE) by a commercial stabilized NZVI with Na-acrylic copolymer (acNZVI) were investigated and compared with those by laboratory-synthesized NZVI and carboxymethyl cellulose (CMC)-stabilized NZVI particles. Results show that the degradation of TCE by acNZVI was faster than that by NZVI and CMC-NZVI. Increase in temperature enhanced the degradation rate and efficiency of TCE with acNZVI. The activation energy of TCE degradation by acNZVI was estimated to be 23 kJ/mol. The degradation rate constants of TCE decreased from 0.064 to 0.026 min(-1) with decrease in initial pH from 9.03 to 4.23. Common groundwater anions including NO3(-), Cl(-), HCO3(-), and SO4(2-) inhibited slightly the degradation efficiencies of TCE by acNZVI. The Na-acrylic copolymer-stabilized NZVI, which exhibited high degradation kinetics and efficiency, could be a good remediation agent for chlorinated organic compounds.


Assuntos
Resinas Acrílicas/química , Água Subterrânea/análise , Ferro/química , Nanopartículas/química , Sódio/química , Tricloroetileno/química , Cinética
18.
ACS Appl Bio Mater ; 7(1): 498-507, 2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-38149601

RESUMO

Traditional hydrogel dressings generally have poor mechanical properties and stability when subjected to external stress due to the undesirable chain entanglement structure of their single valence bond compositions. Therefore, it is particularly important to develop a type of gel dressing with good mechanical strength, stability, and environment-friendly monitoring. In this work, a transparent, pH-sensitive, highly stretchable, and biocompatible anthocyanidin ionogel dressing was prepared, realizing green and accurate detection. Attributed to the antibacterial activity of the ionic liquid, the biocompatibility of the pectin, and the ability to scavenge free radicals of the anthocyanidin, the ionogel dressing exhibited excellent re-epithelialization in the 14 day wound healing process. Besides, changes in pH values monitoring of the ionogel over 3 days coincided with normal wound exudate. The obtained ionogel also showed good water retention, swelling properties, mechanical stretchability, and 5 week stability, illustrating great potential in wound dressings.


Assuntos
Antocianinas , Bis-Fenol A-Glicidil Metacrilato , Cicatrização , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio
19.
Langmuir ; 29(21): 6308-16, 2013 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-23638901

RESUMO

Chiral coordination polymers (CPs) have been prepared at the air-water interface by using the ligand of 1,4-bis(9-O-dihydroquininyl)anthraquinone [(DHQ)2AQN] and its enantiomer of 1,4-bis(9-O-dihydroquinidinyl)anthraquinone [(DHQD)2AQN] as linkers and AgNO3 as the connector. Surface pressure-area isotherms indicated that both ligands could form insoluble monomolecular layers on the pure water and AgNO3 subphase surfaces. Compared with the average molecular area on the pure water surface, that of the ligand increased about 10% when its monolayer was formed on the AgNO3 subphase surface due to the formation of Ag-(DHQ)2AQN and Ag-(DHQD)2AQN chiral CPs. These monolayers were deposited on the quartz, Si, and indium tin oxide (ITO) substrate surfaces via the Langmuir-Blodgett (LB) method. The as-prepared LB films were characterized by using UV-vis absorption and fluorescence spectroscopy, circular dichroism and X-ray photoelectron spectroscopy, as well as by using a scanning electron microscope and atomic force microscope. Broad fluorescence emissions were measured at about 365 and 525 nm for the ligands in the methanol solutions. The second emission red shifted to about 555 nm in the LB films of both pure ligands and their Ag-directed CPs. A couple of well-reversible redox waves were recorded and centered at about -0.2 ~ -0.3 V (vs Ag/AgCl) for the ITO electrode covered by the LB films of (DHQ)2AQN, (DHQD)2AQN, or of the Ag(+)-directed CPs, which were designated to one electron transfer process of the ligands. Small aggregates were observed for the LB films prepared at the lower surface pressures, which were compressed to form more uniform two-dimensional layers at the higher surface pressures.


Assuntos
Antraquinonas/química , Polímeros/química , Polímeros/síntese química , Éteres , Ligantes , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
20.
Nature ; 446(7133): 288-93, 2007 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-17361176

RESUMO

Detachment of the three tiny middle ear bones from the reptilian mandible is an important innovation of modern mammals. Here we describe a Mesozoic eutriconodont nested within crown mammals that clearly illustrates this transition: the middle ear bones are connected to the mandible via an ossified Meckel's cartilage. The connected ear and jaw structure is similar to the embryonic pattern in modern monotremes (egg-laying mammals) and placental mammals, but is a paedomorphic feature retained in the adult, unlike in monotreme and placental adults. This suggests that reversal to (or retention of) this premammalian ancestral condition is correlated with different developmental timing (heterochrony) in eutriconodonts. This new eutriconodont adds to the evidence of homoplasy of vertebral characters in the thoraco-lumbar transition and unfused lumbar ribs among early mammals. This is similar to the effect of homeobox gene patterning of vertebrae in modern mammals, making it plausible to extrapolate the effects of Hox gene patterning to account for homoplastic evolution of vertebral characters in early mammals.


Assuntos
Evolução Biológica , Mamíferos/anatomia & histologia , Mamíferos/classificação , Animais , Padronização Corporal/genética , Osso e Ossos/metabolismo , Orelha/anatomia & histologia , Extinção Biológica , Extremidades/anatomia & histologia , Pé/anatomia & histologia , Regulação da Expressão Gênica no Desenvolvimento , Genes Homeobox/genética , Arcada Osseodentária/anatomia & histologia , Mamíferos/embriologia , Mamíferos/genética , Camundongos , Filogenia
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