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2.
Int J Obstet Anesth ; 60: 104251, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39226639

RESUMO

Pregnancy in patients with dilated cardiomyopathy carries a significantly increased risk of maternal mortality or severe morbidity, and pregnancy is typically considered contraindicated for patients with severely reduced ventricular function. Nonetheless, anesthesiologists will still encounter patients with cardiomyopathy requiring delivery or termination care. This review describes how NT-ProBNP testing and echocardiography can help with early recognition of heart failure in pregnancy, and describes a suggested approach to anesthetic management of patients with cardiomyopathies or acute heart failure, including hemodynamic goals, use of vasoactive medications and mechanical support. Vaginal delivery, with effective neuraxial anesthesia is the preferred mode of delivery in most patients with cardiomyopathy, with cesarean delivery reserved for maternal or fetal indications. The Pregnancy Heart Team is vital in coordinating the multidisciplinary care necessary to safely support these patients through pregnancy.

3.
Sci Total Environ ; 949: 174618, 2024 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-38986687

RESUMO

Understanding the dynamics of the rumen microbiome is crucial for optimizing ruminal fermentation to improve feed efficiency and addressing concerns regarding antibiotic resistance in the livestock production industry. This study aimed to investigate the adaptive effects of microbiome and the properties of carbohydrate-active enzymes (CAZy) and antibiotic resistance genes (ARGs) in response to dietary protein shifts. Twelve Charolais bulls were randomly divided into two groups based on initial body weight: 1) Treatment (REC), where the animals received a 7 % CP diet in a 4-week restriction period, followed by a 13 % CP diet in a 2-week re-alimentation period; 2) Control (CON), where the animals were fed the 13 % CP diet both in the restriction period and the re-alimentation period. Protein restriction decreased the concentrations of acetate, propionate, isovalerate, glutamine, glutamate, and isoleucine (P < 0.05), while protein re-alimentation increased the concentrations of arginine, methionine sulfoxide, lysine, and glutamate (P < 0.05). Protein restriction decreased the relative abundances of Bacteroidota but increased Proteobacteria, with no difference observed after re-alimentation. Protein restriction decreased relative abundances of the genera Bacteroides, Prevotella, and Bifidobacterium. Following protein recovery, Escherichia was enriched in CON, while Pusillibacter was enriched in REC, indicating that distinct microbial adaptations to protein shifts. Protein restriction increased GH97 while reducing GH94 and GT35 compared to CON. Protein restriction decreased abundances of KO genes involved in VFA production pathways, while they were recovered in the re-alimentation period. Protein restriction reduced tet(W/32/O) abundances but increased those of tet(X), nimJ, and rpoB2. Following protein re-alimentation, there was a decrease in ErmQ and tet(W/N/W), and an increase in Mef(En2) compared to CON, highlighting the impact of dietary protein on the distribution of antibiotic-resistant bacteria. Overall, comprehensive metagenomic analysis reveals the dynamic adaptability of the microbiome in response to dietary shifts, indicating its capacity to modulate carbohydrate metabolism and ARGs in response to protein availability.


Assuntos
Ração Animal , Rúmen , Rúmen/microbiologia , Rúmen/metabolismo , Animais , Ração Animal/análise , Microbioma Gastrointestinal , Bovinos , Proteínas Alimentares/metabolismo , Fermentação , Metagenômica , Dieta com Restrição de Proteínas , Masculino , Microbiota
4.
Nan Fang Yi Ke Da Xue Xue Bao ; 44(5): 950-959, 2024 May 20.
Artigo em Chinês | MEDLINE | ID: mdl-38862453

RESUMO

OBJECTIVE: To propose a CT truncated data reconstruction model (DDTrans) based on projection and image dualdomain Transformer coupled feature learning for reducing truncation artifacts and image structure distortion caused by insufficient field of view (FOV) in CT scanning. METHODS: Transformer was adopted to build projection domain and image domain restoration models, and the long-range dependency modeling capability of the Transformer attention module was used to capture global structural features to restore the projection data information and enhance the reconstructed images. We constructed a differentiable Radon back-projection operator layer between the projection domain and image domain networks to enable end-to-end training of DDTrans. Projection consistency loss was introduced to constrain the image forwardprojection results to further improve the accuracy of image reconstruction. RESULTS: The experimental results with Mayo simulation data showed that for both partial truncation and interior scanning data, the proposed DDTrans method showed better performance than the comparison algorithms in removing truncation artifacts at the edges and restoring the external information of the FOV. CONCLUSION: The DDTrans method can effectively remove CT truncation artifacts to ensure accurate reconstruction of the data within the FOV and achieve approximate reconstruction of data outside the FOV.


Assuntos
Algoritmos , Artefatos , Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X , Tomografia Computadorizada por Raios X/métodos , Processamento de Imagem Assistida por Computador/métodos , Humanos , Imagens de Fantasmas
5.
Eur Rev Med Pharmacol Sci ; 28(4): 1541-1553, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38436187

RESUMO

OBJECTIVE: In recent years, Helicobacter pylori (H. pylori) has been increasingly associated with extra-digestive manifestations, including scleroderma, rheumatism, and blood system diseases. Iron deficiency anemia (IDA) is a common chronic disease worldwide, with an insidious onset, but as the disease progresses, it will eventually seriously affect the quality of life of patients. The aim of our study was to investigate the relationship between H. pylori infection, iron deficiency (ID), and IDA, and to identify potential serological markers. PATIENTS AND METHODS: We conducted a cross-sectional study of 998 individuals who had regular physical examinations at Beijing Shijitan Hospital from January 2021 to March 2022. We detected H. pylori infection by the 13C breath test, and recorded the patient's serum iron, ferritin, transferrin saturation, blood count, etc. We assessed the association between IDA and H. pylori infection and related serum markers using logistic regression and multiple linear regression. Afterward, we analyzed the correlation between sex and potential serum biomarkers. RESULTS: Among all study participants, 57.5% of patients had H. pylori and 42.5% did not have H. pylori. ID and IDA were significantly associated with H. pylori infection in women (p=0.031). This association persisted after further adjustment for sex, metabolic variables, liver function, and kidney function. Fasting blood glucose, triglycerides, and uric acid may be associated with IDA. CONCLUSIONS: In women, H. pylori infection is associated with ID and IDA. The relationship between H. pylori and IDA may be mediated by glycometabolism, lipid metabolism, and uric acid metabolism.


Assuntos
Anemia Ferropriva , Infecções por Helicobacter , Helicobacter pylori , Deficiências de Ferro , Humanos , Feminino , Anemia Ferropriva/epidemiologia , Infecções por Helicobacter/complicações , Infecções por Helicobacter/epidemiologia , Estudos Transversais , Qualidade de Vida , Ácido Úrico
8.
Skin Res Technol ; 29(7): e13402, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37522495

RESUMO

BACKGROUND: Age prediction powered by artificial intelligence (AI) can be used as an objective technique to assess the cosmetic effect of rejuvenation surgery. Existing age-estimation models are trained on public datasets with the Caucasian race as the main reference, thus they are impractical for clinical application in Chinese patients. METHODS: To develop and select an age-estimation model appropriate for Chinese patients receiving rejuvenation treatment, we obtained a face database of 10 529 images from 1821 patients from the author's hospital and selected two representative age-estimation algorithms for the model training. The prediction accuracies and the interpretability of calculation logic of these two facial age predictors were compared and analyzed. RESULTS: The mean absolute error (MAE) of a traditional support vector machine-learning model was 10.185 years; the proportion of absolute error ≤6 years was 35.90% and 68.50% ≤12 years. The MAE of a deep-learning model based on the VGG-16 framework was 3.011 years; the proportion of absolute error ≤6 years was 90.20% and 100% ≤12 years. Compared with deep learning, traditional machine-learning models have clearer computational logic, which allows them to give clinicians more specific treatment recommendations. CONCLUSION: Experimental results show that deep-learning exceeds traditional machine learning in the prediction of Chinese cosmetic patients' age. Although traditional machine learning model has better interpretability than deep-learning model, deep-learning is more accurate for clinical quantitative evaluation. Knowing the decision-making logic behind the accurate prediction of deep-learning is crucial for deeper clinical application, and requires further exploration.


Assuntos
Inteligência Artificial , População do Leste Asiático , Humanos , Algoritmos , Bases de Dados Factuais , Aprendizado de Máquina , Face , Reconhecimento Facial Automatizado , Envelhecimento
9.
Zhonghua Jie He He Hu Xi Za Zhi ; 46(6): 614-618, 2023 Jun 12.
Artigo em Chinês | MEDLINE | ID: mdl-37278179

RESUMO

With the emergence of new tuberculosis patients, the number of patients with tuberculosis sequelae is increasing, which not only increases the medical burden of tuberculosis sequelae year by year, but also affects the health-related quality of life (HRQOL) of patients. The HRQOL of patients with tuberculosis sequelae has gradually received attention, but there are few relevant studies. Studies have shown that HRQOL is related to various factors such as post-tuberculosis lung disease, adverse reaction to anti-tuberculosis drugs, decreased physical activity, psychological barriers, low economic status and marital status. This article reviewed the current situation of HRQOL in patients with sequelae of tuberculosis and its influencing factors, in order to provide a reference for improving the quality of life of patients with sequelae of tuberculosis.


Assuntos
Qualidade de Vida , Tuberculose , Humanos , Qualidade de Vida/psicologia , Tuberculose/tratamento farmacológico , Antituberculosos/efeitos adversos
11.
Sci Adv ; 9(8): eade8222, 2023 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-36812307

RESUMO

Myelodysplastic syndrome (MDS) is a clonal malignancy arising in hematopoietic stem cells (HSCs). The mechanisms of MDS initiation in HSCs are still poorly understood. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway is frequently activated in acute myeloid leukemia, but in MDS, PI3K/AKT is often down-regulated. To determine whether PI3K down-regulation can perturb HSC function, we generated a triple knockout (TKO) mouse model with Pik3ca, Pik3cb, and Pik3cd deletion in hematopoietic cells. Unexpectedly, PI3K deficiency caused cytopenias, decreased survival, and multilineage dysplasia with chromosomal abnormalities, consistent with MDS initiation. TKO HSCs exhibit impaired autophagy, and pharmacologic autophagy induction improved HSC differentiation. Using intracellular LC3 and P62 flow cytometry and transmission electron microscopy, we also observed abnormal autophagic degradation in patient MDS HSCs. Therefore, we have uncovered an important protective role for PI3K in maintaining autophagic flux in HSCs to preserve the balance between self-renewal and differentiation and to prevent MDS initiation.


Assuntos
Síndromes Mielodisplásicas , Fosfatidilinositol 3-Quinases , Camundongos , Animais , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Células-Tronco Hematopoéticas , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Diferenciação Celular , Camundongos Knockout
12.
J Hosp Infect ; 133: 73-80, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36646137

RESUMO

BACKGROUND: Pathogens causing infections are in many cases transmitted via the hands of personnel. Thus, hand antisepsis has strong epidemiological evidence of infection prevention. Depending on various factors, hand antisepsis adherence ranges between 9.1% and 85.2%. AIM: To evaluate a new transponder system that reminded medical staff to use an alcohol-based hand rub based on indication by giving real-time feedback, to detect hand antisepsis adherence. METHODS: The monitoring system consisted of three components: a portable transponder detecting alcohol-based hand rub and able to give feedback; a beacon recognizing entries to and exits from the patient's surroundings; and a sensor placed at the hand-rub dispensers to count the number of hand rubs. With these components, the system provided feedback when hand antisepsis was not conducted although it was necessary according to moments 1, 4, and 5 of hand antisepsis. Adherence was measured in two use-cases with five phases, starting with the baseline measurement followed by intervention periods and phases without intervention to test the sustainability of the feedback. FINDINGS: Using the monitoring system, hand antisepsis adherence was increased by up to 104.5% in comparison to the baseline measurement. When the intervention ceased, however, hand antisepsis adherence decreased to less than or equal to the baseline measurement. CONCLUSION: A short-term intervention alone is not sufficient to lead to a long-term change in hand antisepsis adherence. Rather, permanent feedback and/or the integration in a multi-modal intervention strategy are necessary.


Assuntos
Desinfecção das Mãos , Higiene das Mãos , Humanos , Retroalimentação , Antissepsia , Mãos , Etanol , 2-Propanol , Cuidados Críticos , Fidelidade a Diretrizes
13.
J Sci Food Agric ; 103(7): 3414-3426, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36710505

RESUMO

BACKGROUND: The objectives of this study were to investigate the effects of taurine on rumen fermentation, rumen bacterial community and metabolomics, nitrogen metabolism and plasma biochemical parameters in beef steers. Six castrated Simmental steers (liveweight 402 ± 34 kg) and three levels of taurine (0, 20, 40 g d-1 ) were assigned in a replicated 3 × 3 Latin square design. Each experimental period included 15 days for adaptation and 5 days for sampling. RESULTS: Supplementing taurine did not affect the ruminal pH or concentrations of ammonia nitrogen and volatile fatty acids (P > 0.10), but linearly increased the ruminal concentrations of taurine (P < 0.001) and microbial crude protein (P = 0.041). Supplementing taurine linearly increased the neutral detergent fiber digestibility (P = 0.018), and tended to linearly increase dry matter digestibility (P = 0.095), tended to increase the fecal nitrogen excretion (P = 0.065) and increased the urinary taurine excretion (P < 0.001). Supplementing taurine quadratically increased the plasma concentration of triglycerides (P = 0.017), tended to linearly decrease growth hormone (P = 0.074), but did not affect other plasma parameters (P > 0.10). Supplementing taurine modified the rumen bacterial community and increased the ruminal concentration of taurine metabolite 2-hydroxyethoxysulfonic acid (P < 0.001). CONCLUSION: It was concluded that taurine improved ruminal microbial crude protein synthesis and increased fiber digestibility through modifying rumen bacterial community. It is necessary to clarify the ruminal hydrolysis of taurine in steers. © 2023 Society of Chemical Industry.


Assuntos
Dieta , Digestão , Animais , Bovinos , Fermentação , Taurina , Rúmen/metabolismo , Nutrientes/metabolismo , Nitrogênio/metabolismo , Ração Animal/análise
14.
J Mech Behav Biomed Mater ; 137: 105563, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36375276

RESUMO

Multi-component lithium disilicate (LD) glasses were ion-exchanged in a pure or mixed nitrate salt bath. The surface morphologies, mechanical properties, chemical stability and ion leaching of ion-exchanged LD glasses before and after storage in artificial saliva for 21 days were investigated. It can be found that chemical stability of ion-exchanged LD glass was temperature-dependent. The residual compressive stress induced by ion-exchange increased the chemical potential of alkali ions in glass, and the ion-exchanged LD glass, especially 235 °C/64 h group, chemical stability in artificial saliva for 21 days were deteriorated. Back-exchange treatment could relax the stress on the outermost layer of the ion-exchanged LD glass without deteriorating its strengthening effect, and back-exchanged LD glass presented good chemical and mechanical stability in artificial saliva. The results might help to enhance the service stability of ion-exchanged LD glass-ceramics in the oral condition.


Assuntos
Porcelana Dentária , Vidro , Saliva Artificial , Teste de Materiais , Vidro/química
15.
Eur Rev Med Pharmacol Sci ; 26(18): 6444-6450, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36196694

RESUMO

OBJECTIVE: To explore the feasibility of the Internet + nursing service mode in family rehabilitation of elderly patients with osteoarthritic diseases. PATIENTS AND METHODS: The control group (n=50) received routine rehabilitation treatment procedures and discharge guidance. For the observation group (n=50), extended nursing rehabilitation service was conducted through the Internet + nursing service platform based on the routine treatment in the control group. RESULTS: (1) The compliance with follow-up of the patients in the observation group was significantly higher than that in the control group; (2) The total satisfaction of patients in the observation group was significantly higher than that in the control group; (3) The VAS (1 month: 4.36±1.15 vs. 5.86±1.61, p<0.05; 3 months 4.36±1.15 vs. 5.86±1.61, p<0.05), SAS (1 month: 37.21±14.16 vs. 49.31±13.45, p<0.05; 3 months 26.73±8.25 vs. 40.33±9.50, p<0.05), SDS (1 month: 32.36±10.15 vs. 46.32±12.61, p<0.05; 3 months 27.11±8.08 vs. 40.62±11.40, p<0.05) and PSQI (1 month: 13.64 ± 1.13 vs. 16.31 ± 3.45, p<0.05; 3 months 11.54 ± 1.87 vs. 15.74 ± 1.36, p<0.05) scores in the observational group were significantly lower than that in control group at one month and three months after discharge. The ADL (1 month: 86.86 ± 4.13 vs. 74.33 ± 3.44, p<0.05; 3 months 90.34 ± 7.87 vs. 78.52 ± 6.36, p<0.05) scores in the observational group were significantly higher than that in control group at one month and three months after discharge. CONCLUSIONS: The extended rehabilitation nursing management for family rehabilitation of elderly patients with osteoarthritic diseases through the Internet + nursing service is a family rehabilitation model suitable for elderly patients with osteoarthritic diseases in China and has positive significance in developing a diversified medical nursing model.


Assuntos
Artropatias , Serviços de Enfermagem , Idoso , Humanos , Internet , Cooperação do Paciente , Alta do Paciente , Qualidade de Vida
16.
J Dairy Sci ; 105(11): 8879-8897, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36085109

RESUMO

To investigate the effects of acetate, propionate, and pH on thermodynamics of volatile fatty acids (VFA) in the rumen, a dual-flow continuous culture study was conducted to quantify production of major VFA, interconversions among the VFA, and H2 and CH4 emissions in a 4 × 4 Latin square design. The 4 treatments were (1) control: pH buffered to an average of 6.75; (2) control plus 20 mmol/d of infused acetate (InfAc); (3) control plus 7 mmol/d of infused propionate (InfPr); and (4) a 0.5-unit decline in pH elicited by adjustment of the buffer (LowpH). All fermentors were fed 40 g of a pelleted diet containing whole alfalfa pellets and concentrate mix pellets (50:50) once daily. After 7 d of treatment, sequential, continuous infusions of [2-13C] sodium acetate (3.5 mmol/d), [U-13C] sodium propionate (2.9 mmol/d), and [1-13C] sodium butyrate (0.22 mmol/d) were carried out from 12 h before feeding for 36 h. Filtered liquid effluent (4 mL) was sampled at 0, 2, 4, 6, 8, 12, 16, and 22 h after feeding, and assessed for VFA concentrations, with another filtered sample (20 mL) used to quantify aqueous concentrations of CH4 and H2. Headspace CH4 and H2 gases were monitored continuously. Ruminal microbes were isolated from the mixed effluent samples, and the microbial community structure was analyzed using the 16S rRNA amplicon sequencing technique. The digestibility of neutral detergent fiber, acid detergent fiber, and starch and microbial C sequestrated from VFA were not affected by treatments. The LowpH treatment increased net propionate production and decreased H2 and CH4 headspace emissions, primarily due to shifts in metabolic pathways of VFA formation, likely due to the observed changes in bacterial community structure. Significant interconversions occurred between acetate and butyrate, whereas interconversions of other VFA with propionate were relatively small. The InfAc and InfPr treatments increased net acetate and propionate production, respectively; however, interconversions among VFA were not affected by pH, acetate, or propionate treatments, suggesting that thermodynamics might not be a primary influencer of metabolic pathways used for VFA formation.


Assuntos
Propionatos , Rúmen , Animais , Rúmen/metabolismo , Propionatos/metabolismo , RNA Ribossômico 16S/metabolismo , Ácido Butírico/metabolismo , Acetato de Sódio , Detergentes/metabolismo , Fermentação , Ácidos Graxos Voláteis/metabolismo , Acetatos/metabolismo , Dieta , Amido/metabolismo , Concentração de Íons de Hidrogênio , Termodinâmica , Gases/metabolismo , Digestão , Ração Animal
17.
Zhonghua Er Ke Za Zhi ; 60(3): 215-220, 2022 Mar 02.
Artigo em Chinês | MEDLINE | ID: mdl-35240741

RESUMO

Objective: To understand the current situation regarding pediatric off-label use of drugs recommendations in Chinese clinical practice guidelines and to make recommendations for standardized reporting format regarding off-label use of drugs for children. Methods: This cross-sectional study was carried out by systematically searching the databases for Chinese guideline consensus articles published in journals between 2018 and 2020 and extracting recommendations regarding off-label use of drugs from those articles. The essential characteristics of the included guidelines, the ranking of off-label drug types, the order of drug information, the type of off-label drug use, and the percentage of citation studies on which the recommendations were based were analyzed. Results: Among 108 studies that included Chinese off-label guidelines and consensus, 364 recommendations on pediatric off-label use of drugs were included. The Chinese Medical Association published the most, 48 out of the 108 studies (44.4%), and of those 14 studies (13.0%) were on infectious and parasitic diseases. Of the 364 recommendations on off-label use of drugs, the most commonly addressed drugs were 16 recommendations (4.4%) for cyclosporine A, 11 recommendations (3.0%) for methotrexate , and 11 recommendations (3.0%) for fentanyl. The most commonly addressed drug categories were as follows: 68 recommendations (18.6%) were immune system drugs, 66 recommendations (18.1%) were anti-infectives, and 56 recommendations (15.4%) were oncology drugs. The most commonly addressed drug information accounts were as follows: 364 recommendations (100.0%) were indications, 204 recommendations (56.0%) were dosages, and 198 recommendations (54.4%) were the route of administration. Based on the instructions approved by the Chinese Food and Drug Administration, the main forms of the off-label drug were as follows: 175 recommendations (48.1%) were unapproved indications, 127 recommendations (34.9%) were unapproved populations, and 72 recommendations (19.8%) were unapproved ages. Only 129 recommendations (35.4%) were cited, mainly including clinical guidelines (48 studies, 23.4%), reviews (22 studies, 10.7%), and pediatric randomized controlled trials (22 studies, 10.7%). Conclusions: Off-label use of drugs is commonly recommended in pediatric guidelines and consensus documents written by Chinese authors. However, the reporting of the recommendations varies widely, and the quality of the supporting evidence is poor.


Assuntos
Uso Off-Label , Preparações Farmacêuticas , Criança , China , Consenso , Estudos Transversais , Humanos
18.
J Mech Behav Biomed Mater ; 126: 105036, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34902754

RESUMO

Lithium disilicate (LD) glass-ceramics with a stoichiometric composition were ion-exchanged in pure NaNO3 or mixed NaNO3 + KNO3 molten salt baths below the glass transition temperature (Tg). The microstructures, surface morphologies, mechanical properties and bioactivities of the ion-exchanged glass-ceramics were studied in detail. It was found that the strength and toughness of LD glass-ceramic could be enhanced from 175 MPa to 0.96 MPa m1/2 before ion-exchange to 546 MPa and 4.31 MPa m1/2 respectively under a lowered ion-exchange temperature because the less stress relaxation. In addition, a gradient of Na+ rich layer in the surface of glass-ceramic was induced by Li+/Na+ exchange, which could be beneficial to the formation of HA (Hydroxyapatite) with nano-size porous after soaking in SBF (Simulated Body Fluid) solution and exhibited better bioactivity compared with the original LD glass-ceramic. The results might provide a reference for the strengthening and biological activation of LD glass-ceramics in bone restoration applications.


Assuntos
Cerâmica , Porcelana Dentária , Vidro , Lítio , Teste de Materiais , Propriedades de Superfície
19.
J Mech Behav Biomed Mater ; 126: 105037, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34906862

RESUMO

OBJECTIVES: This study examined the effects of Li+→Na+ ion-exchange on the early wear performance of dental lithium disilicate (LD) glass-ceramics. METHODS: Specimens with different shapes were prepared using IPS e.max Press as the LD glass-ceramics. Ion-exchange was conducted by placing polished specimens in molten salt containing 25% NaNO3 and 75% KNO3 at 385 °C for 16 or 64 h. The ion-exchanged specimens were analyzed using X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) to investigate the structure and the elemental distribution. Thereafter, the specimens were tested for flexural strength, Vickers hardness, and fracture resistance. A portion of the specimens were tested with a pin-on-disk tribometer with 10 N for 40 × 104 wear cycles in artificial saliva. Wear analysis of the specimens was performed using a 3D profilometer and analyzed with one-way analyses of variance and Tukey's post hoc pairwise comparisons. Worn surfaces were examined with scanning electron microscopy. RESULTS: The LD glass-ceramics exhibited strong time-dependent wear behavior, with typical running-in and steady wear stages. Ion-exchange treatments at 385 °C for 16 h and 64 h both enhanced the mechanical properties and decreased the wear rates of early running-in wear stage. The early wear performance of specimens treated with ion-exchange for long time (64 h) was improved significantly. CONCLUSION: A thicker ion-exchange layer may be obtained by processing ion-exchange for a long time. This protocol improves the early wear performance of the glass-ceramics effectively. CLINICAL SIGNIFICANCE: Dental restorations may fail prematurely due to excessive wear. It is important to improve the early wear performance of the glass-ceramics. Ion-exchange has the potential to strengthen dental LD glass-ceramics. Understanding the effect of ion-exchange on the early wear performance of glass-ceramics provides insight improving the early wear performance of these restorations.


Assuntos
Cerâmica , Corrida , Porcelana Dentária , Teste de Materiais , Propriedades de Superfície
20.
J Sci Food Agric ; 102(6): 2321-2329, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34625977

RESUMO

BACKGROUND: Nitrous oxide (N2 O) is a potent greenhouse gas depleting the stratospheric ozone. Previous studies reported that the thiocyanate (TC) excretion in the urine of cattle fed rapeseed meals containing glucosinolates was positively correlated with the N2 O-nitrogen (N) emissions. The objectives of the experiment were to verify the effects and the mechanism of TC on the N2 O-N emissions from the soil applied with artificial urine using static incubation technique. Four levels of TC, that is 0.00, 0.26, 0.78 and 2.33 mmol L-1 were composited in artificial urine as experimental treatments. Soil inorganic N and bacterial community were analyzed to elucidate the effects of TC on the N2 O-N emissions of artificial urine. RESULTS: Adding TC increased the N2 O-N fluxes, the N2 O-N to N application ratio, and the estimated N2 O-N emissions from the soil applied with artificial urine both linearly and quadratically. The estimated N2 O-N emission (Y, in µmol) was increased with the TC adding level (X, in µmol) in a quadratic manner: Y = 52.57 + 4.47 X - 0.123 X 2 (R 2  = 0.70). Adding TC did not affect the soil bacterial diversity and richness, but increased the relative abundances of Nitrosomonas (both for nitrification and denitrification) and Hyphomicrobium, Lysobacter and Terrimonas (for denitrification), and tended to increase the relative abundances of denitrification and dissimilatory nitrate reduction to ammonium. CONCLUSION: TC increased the N2 O-N emissions of the soil applied with artificial urine possibly through enhancing the denitrification of nitrifiers in the soil. Field experiments are necessary to verify the laboratory results. © 2021 Society of Chemical Industry.


Assuntos
Óxido Nitroso , Solo , Animais , Bovinos , Desnitrificação , Nitrificação , Nitrogênio/análise , Óxido Nitroso/análise , Tiocianatos
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