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1.
Brain ; 146(9): 3608-3615, 2023 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-37143322

RESUMEN

The duplication of the peripheral myelin protein 22 (PMP22) gene causes a demyelinating type of neuropathy, commonly known as Charcot-Marie-Tooth disease type 1A (CMT1A). Development of effective drugs for CMT1A still remains as an unmet medical need. In the present study, we assessed the role of the transforming growth factor beta 4 (TGFß4)/Nodal axis in the pathogenesis of CMT1A. First, we identified PMP22 overexpression-induced Nodal expression in Schwann cells, which might be one of the downstream effectors in CMT1A. Administration of Nodal protein at the developmental stage of peripheral nerves induced the demyelinating phenotype in vivo. Second, we further isolated TGFß4 as an antagonist that could abolish Nodal-induced demyelination. Finally, we developed a recombinant TGFß4-fragment crystallizable (Fc) fusion protein, CX201, and demonstrated that its application had promyelinating efficacy in Schwann cells. CX201 administration improved the demyelinating phenotypes of CMT1A mouse models at both pre-symptomatic and post-symptomatic stages. These results suggest that the TGFß4/Nodal axis plays a crucial role in the pathogenesis of CMT1A and might be a potential therapeutic target for CMT1A.


Asunto(s)
Enfermedad de Charcot-Marie-Tooth , Animales , Ratones , Enfermedad de Charcot-Marie-Tooth/patología , Proteínas de la Mielina/metabolismo , Células de Schwann , Fenotipo , Factor de Crecimiento Transformador beta/metabolismo
2.
Environ Sci Technol ; 57(34): 12794-12805, 2023 08 29.
Artículo en Inglés | MEDLINE | ID: mdl-37579047

RESUMEN

Plastic recycling and reprocessing activities may release organophosphate ester (OPE) flame retardants and plasticizers into the surrounding environment. However, the relevant contamination profiles and impacts remain not well studied. This study investigated the occurrence of 28 OPEs and their metabolites (mOPEs) in rainfall runoffs and agricultural soils around one of the largest plastic recycling industrial parks in North China and identified novel organophosphorus compounds (NOPs) using high-resolution mass spectrometry-based nontarget analysis. Twenty and twenty-seven OPEs were detected in runoff water and soil samples, with total concentrations of 86.0-2491 ng/L and 2.53-199 ng/g dw, respectively. Thirteen NOPs were identified, of which eight were reported in the environment for the first time, including a chlorine-containing OPE, an organophosphorus heterocycle, a phosphite, three novel OPE metabolites, and two oligomers. Triphenylphosphine oxide and diphenylphosphinic acid occurred ubiquitously in runoffs and soils, with concentrations up to 390 ng/L and 40.2 ng/g dw, respectively. The downwind areas of the industrial park showed elevated levels of OPEs and NOPs. The contribution of hydroxylated mOPEs was higher in soils than in runoffs. These findings suggest that plastic recycling and reprocessing activities are significant sources of OPEs and NOPs and that biotransformation may further increase the ecological and human exposure risk.


Asunto(s)
Retardadores de Llama , Plastificantes , Humanos , Plásticos , Compuestos Organofosforados/análisis , Retardadores de Llama/análisis , Suelo , Organofosfatos/análisis , China , Ésteres/análisis , Monitoreo del Ambiente
3.
BMC Oral Health ; 22(1): 462, 2022 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-36324171

RESUMEN

BACKGROUND: The healing period from crown lengthening procedures (CLPs) often delays the final crown delivery. This study aimed to explore the feasibility of a new approach expediting the delivery of the final crowns for teeth requiring CLPs. METHODS: Teeth requiring CLPs and single-crown restorations between the canine and the second molar were included. After the initial tooth preparation, a CLP was performed. In the experimental group, the final tooth preparation and final impression were made during the CLP; the final crown was then delivered at the suture-removal appointment. In the control group, the final impression was made 8 weeks after the CLP. The level of gingival margin (GM), pocket depth (PD), and crestal bone levels (CBLs) were compared between the two groups before CLPs (T0), at delivery of the crowns (T1), and at 12 months in function (T2). RESULTS: Twenty-one lithium-disilicate crowns were delivered to 20 subjects and followed up. The mean interval between the CLPs and the delivery of crowns was 2.5 weeks for the experimental group and 12 weeks for the control group. No significant differences were observed between the two groups in the level of GM, PD, and CBLs at each time point. No significant treatment difference in crestal bone loss was observed between the two groups at T2 (Experimental = -0.11 mm, Control = -0.03 mm; p = 0.67). CONCLUSION: Making the final tooth preparation and the final impression at the CLP significantly reduced the time between the CLP and the delivery of the final crown and showed comparable clinical outcomes.


Asunto(s)
Alargamiento de Corona , Coronas , Proyectos Piloto , Corona del Diente/cirugía , Diente Molar
4.
BMC Oral Health ; 21(1): 39, 2021 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-33482794

RESUMEN

BACKGROUND: The 2018 classification of periodontal disease characterizes the disease with a multidimensional staging and grading system. The purpose of this multicenter study was to examine variations in periodontitis classification among dental practitioners with different postgraduate educational backgrounds at the University of Maryland School of Dentistry and the Loma Linda University School of Dentistry using the 2018 classification. METHODS: This cross-sectional observational study included two cohorts: dental practitioners with periodontal backgrounds (n1 = 31) and those with other educational backgrounds (n2 = 33). The survey instrument contained three periodontitis cases presented with the guideline of the 2018 classification and a questionnaire including closed and open-ended questions. The participants were asked to review each case and to fill out the questionnaire independently. Fisher's exact test was conducted to examine the differences in responses between the two cohorts. Polychoric correlations were calculated to examine the relation between the level of familiarity with the 2018 classification and the accuracy of the classification. RESULTS: The distribution of item responses was significantly different between the two cohorts regarding only one item, grading for Case 1 (p = 0.01). No significant differences in accuracy between the two cohorts were observed except for two items, grading in Case 1 (p = 0.03) and staging in Case 3 (p = 0.04). There were no significant differences in risk factor identification for each case among the two cohorts (p = 1.00, Case 1; p = 0.22, Case 2). Staging in Case 3 ([Formula: see text] = 0.52) and risk factor identification in Case 2 ([Formula: see text]= 0.32) were significantly correlated with familiarity with the 2018 classification. CONCLUSION: A fair level of agreement in periodontitis classification was observed among dental practitioners with different educational backgrounds when the 2018 classification was used. The periodontal cohort showed better agreement levels and partially better accuracy. Risk factor identification for periodontal disease was difficult regardless of the educational background.


Asunto(s)
Enfermedades Periodontales , Periodontitis , Estudios Transversales , Odontólogos , Humanos , Periodontitis/diagnóstico , Rol Profesional
5.
Eur J Dent Educ ; 25(4): 641-648, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33259658

RESUMEN

INTRODUCTION: This study aimed to observe changes in working posture by measuring the REBA (Rapid Entire Body Assessment) score of dental hygiene students according to digital sound feedback linked with a smartphone application. METHODS: This study was conducted on 28 fourth-year dental hygiene students who received theoretical and practical training on dental posture in the second year and then practised on mannequins and patients for about four semesters. Periodontal instrumentation was performed freely by applying digital sound notification feedback for four weeks after baseline, 30 minutes per week. REBA was measured after performing periodic structure construction without providing digital sound notification feedback for the last 1-2 minutes. Follow-up was conducted the same way 2-3 weeks after the intervention period. RESULTS: The REBA score for total, neck and trunk of all subjects showed statistically significant decreases post-intervention compared with the baseline scores (total p < .001, neck p < .001 and trunk p = .042). CONCLUSIONS: A digital sound feedback system was shown to be effective in encouraging correct working posture in dental hygiene students by helping them improve their REBA scores.


Asunto(s)
Educación en Odontología , Higiene Bucal , Higienistas Dentales , Retroalimentación , Humanos , Postura , Estudiantes
6.
Int J Mol Sci ; 21(12)2020 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-32575639

RESUMEN

Adult stem cells have been developed as therapeutics for tissue regeneration and immune regulation due to their self-renewing, differentiating, and paracrine functions. Recently, a variety of adult stem cells from the oral cavity have been discovered, and these dental stem cells mostly exhibit the characteristics of mesenchymal stem cells (MSCs). Dental MSCs can be applied for the replacement of dental and oral tissues against various tissue-damaging conditions including dental caries, periodontitis, and oral cancers, as well as for systemic regulation of excessive inflammation in immune disorders, such as autoimmune diseases and hypersensitivity. Therefore, in this review, we summarized and updated the types of dental stem cells and their functions to exert therapeutic efficacy against diseases.


Asunto(s)
Células Madre Adultas/citología , Enfermedades de la Boca/terapia , Boca/citología , Células Madre Adultas/trasplante , Caries Dental , Humanos , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/citología
7.
Eur J Dent Educ ; 24(4): 734-740, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32603011

RESUMEN

AIM: The aim of this study was to find ways to improve reliability of cut-off scores that are typically used to make high-stake decisions in dental education by empirically comparing two different rating methods, Yes/No and Percentage methods. MATERIAL AND METHODS: The two rating methods are commonly used when the Angoff's method is applied to determine a cut-off score that divides the examinees into minimally competent group (pass) and incompetent group (fail). The expert panel data were collected using both methods from 11 to 13 panel members in two consecutive years, respectively; The data were analysed within the generalisability theory framework to quantify relative influences of each factor (eg panel, item, rating rounds) on the variability of cut-off scores, standard error of measurement and panel agreement. RESULTS: The results suggest that (a) the two methods can make a substantial difference in overall success rates for college senior students, (b) item-related variance components are generally large and whilst rater-related variance components are small, (c) standard errors of measurement for the cut-off scores decreased from Cohort 1 to Cohort 2 as the number of items are increased and as the expert panel members are more trained and (d) the Percentage method yielded higher agreement amongst the panel in both years. The results provide practical guidelines for dental educators who make efforts to control the quality of final competency exams and cut-off scores with respect to standard setting practices and panel data analysis. CONCLUSION: It can be concluded that evaluations with Percentage method results in more reliable outcomes compared to those with Yes/No method when criterion-referenced assessment is applied to determine the cut-off scores of competency tests at schools.


Asunto(s)
Competencia Clínica , Evaluación Educacional , Educación en Odontología , Humanos , Estándares de Referencia , Reproducibilidad de los Resultados
8.
BMC Med Educ ; 19(1): 477, 2019 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-31888595

RESUMEN

BACKGROUND: The ICAP framework based on cognitive science posits four modes of cognitive engagement: Interactive, Constructive, Active, and Passive. Focusing on the wide applicability of discussion as interactive engagement in medical education, we investigated the effect of discussion when it was preceded by self-study and further investigated the effect of generating questions before discussions. METHODS: This study was conducted in the second semester of 2018 and was participated in by 129 students majoring in health professions, including medicine, dentistry, veterinary medicine, and nursing. The students were assigned to four different trial groups and were asked to fill out a Subjective Mental Effort Questionnaire after completing each session. Their performance in posttest scores was analyzed using Bonferroni test, and mental effort was analyzed using mediation analysis. RESULTS: These results indicated that the self-study and question group had the highest performance and that the lecture and summary group had the lowest performance when comparing the total score. Using the analysis of mental effort, it was confirmed that the relationship between different study conditions and post-test performance was mediated by mental effort during test. CONCLUSIONS: Our findings support the ICAP framework and provide practical implications for medical education, representing the fact that students learn more when they are involved in active learning activities, such as self-study and question generation, prior to discussions.


Asunto(s)
Procesos de Grupo , Empleos en Salud/educación , Aprendizaje Basado en Problemas/métodos , Humanos , Autoeficacia , Encuestas y Cuestionarios
9.
Biomacromolecules ; 18(4): 1064-1073, 2017 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-28192668

RESUMEN

The essential pathophysiological roles of hyaluronic acid (HA) strongly depend on HA binding and HA size. Here we deployed the atomic vision of molecular dynamics (MD) simulation to experimentally investigate the influence of C-terminal mutations of Streptococcus equisimilis hyaluronan synthase (SeHAS) on HA product synthesis in Escherichia coli. R413 was vital for HA production, as the removal or mutation of R413 led to inactivation of SeHAS. MD simulations indicated that R406-R413 constituted an HA-binding pattern that stabilized the HA-SeHAS complex. We further increased HA product size via site-directed mutation of the SeHAS C-terminal residues 414-417 based on the hypothesis that higher binding affinity between the SeHAS C-terminus and HA would lead to larger HA size, underlying the important role of the HA-SeHAS interaction in HA size control. W410A and T412A mutations also completely deactivated SeHAS. Moreover, a catalysis-transformation-translocation model was proposed for the HA synthesis and translocation processes.


Asunto(s)
Glucuronosiltransferasa/metabolismo , Ácido Hialurónico/química , Polímeros/química , Streptococcus/enzimología , Arginina/química , ADN Bacteriano/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Hialuronano Sintasas , Lisina/química , Simulación de Dinámica Molecular , Peso Molecular , Mutación , Streptococcus/genética
10.
Water Sci Technol ; 69(9): 1788-97, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24804651

RESUMEN

The process of simultaneous nitrification and denitrification (SND) of immobilized microorganisms in polyurethane form is discussed. The effect of different positions within the polyurethane carrier on microbial community response for the SND process is investigated by a combination of denaturing gradient gel electrophoresis profiles of the 16S rRNA gene V3 region and scanning electron microscopy. Results show that polyurethane, which consists of a unique porous structure, is an ideal platform for biofilm stratification of aerobe, anaerobe and facultative microorganisms in regard to the SND process. The community structure diversity response to different positions was distinct. The distributions of various functional microbes, detected from the surface aerobic stratification to the interior anaerobic stratification of polyurethane, were mainly nitrifying and denitrifying bacteria. Meanwhile aerobic denitrifying bacteria such as Paracoccus sp., Agrobacterium rubi and Ochrobactrum sp. were also adhered to the interior and surface of polyurethane. The SND process occurring on polyurethane foam was carried out by two independent processes: nitrogen removal and aerobic denitrification.


Asunto(s)
Bacterias/metabolismo , Poliuretanos/química , Bacterias/clasificación , Bacterias/genética , ADN Bacteriano/genética , Desnitrificación , Microscopía Electrónica de Rastreo , Nitrificación , Nitrógeno , Filogenia
11.
Zhongguo Gu Shang ; 37(7): 676-83, 2024 Jul 25.
Artículo en Zh | MEDLINE | ID: mdl-39104068

RESUMEN

OBJECTIVE: To investigate the effect of Polyetheretherketone (PEEK) rod semi-rigid pedicle screw fixation system in lumbar spine non-fusion surgery. METHODS: A total of 74 patients with tow-level lumbar degenerative diseases who underwent surgery from March 2017 to December 2019 were divided into PEEK rod group and titanium rod group. In the PEEK rod group, there were 34 patients, including 13 males and 21 females, aged from 51 to 79 years old with an average of (62.4±6.8) years old;There were 1 patient of L1-L3 segments, 7 patients of L2-L4 segments, 20 patients of L3-L5 segments and 6 patients of L4-S1 segments. In the titanium rod group, there were 40 patients, including 17 males and 23 females, aged from 52 to 81 years old with an average of (65.2±7.3) years old;There were 3 patient of L1-L3 segments, 11 patients of L2-L4 segments, 19 patients of L3-L5 segments and 7 patients of L4-S1 segments. The general conditions of operation, such as operation time, intraoperative blood loss, postoperative drainage was recorded. The visual analogue scale (VAS) for low back pain and Oswestry disability index (ODI) were compared in preoperatively and postoperatively(3 months, 12 months and last follow-up) between two groups. The change of range of motion (ROM) was observed by flexion and extension x-ray of lumbar. RESULTS: All patients successfully completed the operation. The follow-up time ranged from 22 to 34 months with an average of(26.8±5.6) months. The operative time (142.2±44.7) min and intraoperative blood loss(166.5±67.4)ml in PEEK group were lower than those in titanium group [(160.7±57.3) min、(212.8±85.4) ml](P<0.05). There was no significant differences in postoperative drainage between the two groups (P>0.05). At the final follow-up visit, in PEEK group and titanium group VAS of low back pain[(0.8±0.4) points vs (1.0±0.5) points], VAS for leg pain [ (0.7±0.4) points vs (0.8±0.5) points] and ODI [(9.8±1.6)% vs (12.1±1.5)%] were compared with preoperative [ (5.8±1.1) points vs (6.0±1.1)points], [ (7.2±1.7) points vs (7.0±1.6) points], [(68.5±8.9)% vs(66.3±8.2)%] were significantly different(P<0.05). There was no significant difference in VAS scores between the two groups at each postoperative time point (P>0.05). At 3 months after surgery, there was no difference in ODI between the two groups (P>0.05). There were significant differences in ODI between PEEK group and titanium rod group at 12 months [(15.5±2.1)% vs (18.4±2.4)%] and at the last follow-up [(9.8±1.6)% vs (12.1±1.5)%] (P<0.05). The total range of motion (ROM) of lumbar decreased in both groups after surgery. At 12 months after surgery and the last follow-up, the PEEK group compared with the titanium rod group, the total range of motion of lumbar was statistically significant (P<0.05). The range of motion (ROM) of the fixed segments decreased in both groups after surgery. The ROM of the fixed segments in PEEK group decreased from (9.5±4.6)° to (4.1±1.9)° at the last follow-up (P<0.05), which in the titanium rod group was decreased from (9.8±4.3)°to (0.9±0.5)° at the last follow-up (P<0.05). The range of motion (ROM) of upper adjacent segment increased in both groups, there was statistical significance in the ROM of upper adjacent segment between the two groups at 12 months after surgery and the last follow-up, (P<0.05). There was no screw loosening and broken rods in both groups during the follow-up period. CONCLUSION: The PEEK rod semi-rigid pedicle screw internal fixation system used in lumbar non-fusion surgery can retain part of the mobility of the fixed segment, showing comparable short-term clinical efficacy to titanium rod fusion. PEEK rod semi-rigid pedicle screw internal fixation system is a feasible choice for the treatment of lumbar spine degenerative diseases, and its long-term efficacy needs further follow-up observation.


Asunto(s)
Benzofenonas , Cetonas , Vértebras Lumbares , Tornillos Pediculares , Polietilenglicoles , Polímeros , Humanos , Femenino , Masculino , Persona de Mediana Edad , Anciano , Vértebras Lumbares/cirugía , Anciano de 80 o más Años
12.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 30(6): 1171-5, 2013 Dec.
Artículo en Zh | MEDLINE | ID: mdl-24645590

RESUMEN

The aim of the present study was to detect the transmission rate of ultrasonic low intensity pulsed ultrasound (LIPUS) through polytetrafluoroethylene (PTFE) membrane (Thickness: 0.01 mm) and Bio-Gide collagen membrane, and to provide the basis for the barrier membrane selection on the study of LIPUS combined with guided tissue regeneration (GTR). The ultrasonic (LIPUS, frequency 1.5 MHz, pulse width 200 micros, repetition rate 1.0 kHz) transmission coefficient of the two kinds of barrier membrane were detected respectively through setting ten groups from 10 to 100mW/cm2 every other 10 mW/cm2. We found in the study that the ultrasonic transmission coefficient through 0.01 mm PTFE membrane was 78.1% to 92.%, and the ultrasonic transmission coefficient through Bio-Gide collagen membrane was 43.9% to 55.8%. The ultrasonic transmission coefficient through PTFE membrane was obviously higher than that through Bio-Gide collagen membrane. The transmission coefficient of the same barrier membrane of the ultrasonic ion was statistically different under different powers (P < 0.05). The results showed that the ultrasonic transmittance rates through both the 0.01 mm PTFE membrane and Bio-Gide collagen membrane were relatively high. We should select barrier membranes based on different experimental needs, and exercise ultrasonic transmission coefficient experiments to ensure effective power.


Asunto(s)
Colágeno/química , Membranas Artificiales , Politetrafluoroetileno/química , Ultrasonido , Materiales Biocompatibles , Permeabilidad
13.
Colloids Surf B Biointerfaces ; 228: 113436, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37406463

RESUMEN

This study aimed to investigate the bioflocculation characteristics of bound extracellular polymers substances (B-EPS), which were extracted from Pseudomonas sp. XD-3. The flocculation efficiency of B-EPS achieved about 80%- 95% with an initial pH of 4-7, kaolin concentrations of 3-7 g L-1, temperature of 25-100 â„ƒ and B-EPS dosage of 9-105 mg L-1. The bioflocculation process of B-EPS conformed to pseudo-second-order kinetic mode, suggesting that the bioflocculation belonged to chemical adsorption process. Enzymatic hydrolysis experiments demonstrated that both polysaccharides and proteins were active components for bioflocculation. The polysaccharides were irregular aggregates with rough and porous surfaces and contained hydroxyl and carboxyl groups, which helped to promote bridging effect. Ribose, glucose and galactose were the main monosaccharides of polysaccharides. The molecular weight of the polysaccharides was relatively small, but the relatively loose configuration exposed more ion bridging sites, thus promoting the bioflocculation. Optimizing the ingredients of culture medium and culture time for B-EPS were effective strategies to increase the yield of flocculation active components. When the conditions were 10% of 2 g L-1 KH2PO4 + 5 g L-1 K2HPO4, 0.05% of Tween-80, citrate as carbon source and 32-48 h of culture time, both proteins and polysaccharides in B-EPS were significantly improved. This study gives an in-deep understanding on the flocculation characteristics of a novel bioflocculant from Pseudomonas sp. XD-3, which is conducive to the widespread application of bioflocculation.


Asunto(s)
Polisacáridos , Pseudomonas , Matriz Extracelular de Sustancias Poliméricas , Temperatura , Floculación , Polisorbatos
14.
PLoS One ; 18(4): e0275049, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37011085

RESUMEN

The effects of cooling rate, Ti content, and casting temperature on titanium compounds for high titanium steel were investigated. In-situ observation of high titanium steel during remelting and solidification was carried out by using a High Temperature Confocal Scanning Laser Microscope (HTCSLM), and the observed results were in good agreement with the thermodynamic and kinetic calculations. The observation and calculation results both show that the inclusions in high titanium steel first precipitate in the form of TiN, followed by TiC precipitates as temperature decreases, eventually forming TiCxN1-x type inclusions at room temperature. The initial precipitation temperature of the inclusions increases with the increase of Ti content in molten steel, whereas casting temperature has little effect on the initial precipitation temperature of inclusions. In addition, the size of TiN inclusions increases with the increase of Ti content in steel but decreases with the increase in cooling rate.


Asunto(s)
Acero , Titanio , Frío , Temperatura
15.
Biotechnol Bioeng ; 109(1): 289-94, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21809335

RESUMEN

We developed a novel one-pot synthetic strategy for preparing monodisperse polyethylene glycol diacrylate (PEGDA) microdroplets via organoclay-assisted interfacial polymerization approach for Escherichia coli encapsulation. Based on the mechanism of spontaneous and rapid polymerization of PEGDA precursor solution with Mg-organoclay, the prepared PEGDA microdroplets have uniform size and fine round shape, with size range of 74-118 µm. The size of microdroplets can be controlled through the changing continuous phase flow rate. Organoclay-assisted polymerization method provides a unique environment to produce non-toxic ways of fabricating microorganism encapsulated microdroplets and to prohibit microdroplets merge during the processes. Furthermore, we successfully carried out to entrap E. coli inside of the PEGDA microdroplets. E. coli expressing a green fluorescent protein shows a good viability inside the PEGDA microdroplets. The in situ microfluidic synthetic method provides a novel approach for the preparation of monodisperse PEGDA microdroplets via a one-pot route.


Asunto(s)
Acrilatos/síntesis química , Células Inmovilizadas/fisiología , Escherichia coli/fisiología , Microfluídica/métodos , Microesferas , Polietilenglicoles/síntesis química
16.
Environ Sci Technol ; 46(20): 11273-9, 2012 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-22974141

RESUMEN

Desulfurization residuals (using NaOH sorbent) were regenerated electrochemically, and at the same time sulfur in the flue gas was recovered as H(2)SO(4) and H(2) was produced as a clean energy. Since industrialization should always be the final goal to pursue for lab technologies and the evolution of pilot- and full-scale commercial reactors has taken place relatively slowly, this paper is aimed to develop an electroreactor on a sufficiently large scale to evaluate the application potential of the proposed regeneration process. The following key design parameters are discussed: (1) voltage distributions over electrode, membrane, and electrolyte; and (2) scaling up correlation based on lab-scale reactor operation parameters. Thereafter, in the developed reactor, the desulfurization residuals using NaOH sorbent from a semidry flue gas desulfurization (FGD) facility of a power plant in Shandong Province were regenerated and it is significant to note that the electrochemical efficiency of the designed reactor is comparable to that of the chlor-alkali industry, showing that the technology is environmentally friendly and economically feasible. If this technology is to be employed for FGD, the facility could be a profit-generating manufacturing part instead of a currently money-consuming burden for the plants.


Asunto(s)
Contaminantes Atmosféricos/análisis , Membranas Artificiales , Centrales Eléctricas , Reciclaje/métodos , Azufre/análisis , Contaminantes Atmosféricos/química , Contaminación del Aire/estadística & datos numéricos , Azufre/química
17.
Braz J Microbiol ; 53(2): 991-1000, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35229279

RESUMEN

Increasing evidence demonstrated the oral microbial community profile characteristics affected by conventional cigarettes smoking, but few studies focus on oral microbiome in response to electronic cigarettes (E-cigarettes). This study aimed to investigate the effect of E-cigarettes on the oral microbiome and to describe the difference of oral community profiles between E-cigarette smokers and tobacco smokers. 16S rRNA V4 gene sequencing was performed to investigate the oral microbial profiles of 5 E-cigarette smokers, 14 tobacco smokers, 8 quitting tobacco smokers, and 6 nonsmokers. The Chao1, ACE, and Shannon diversity indexes increased significantly in saliva samples collected from E-cigarette smokers and tobacco smokers compared to the non-smokers, and no significant difference was found in alpha diversity between E-cigarette smokers and tobacco smokers. The main phyla Proteobacteria, Firmicutes, Bacteroidetes, and Fusobacteria and major genera Neisseria, Streptococcus, Prevotellaceae, Fusobacterium, and Porphyromonas dominated in the smoking groups, while Actinobacteria, Proteobacteria, Firmicutes, Bacteroidetes, and Fusobacteria became the dominant phyla along with the genera Corynebacterium, Neisseria, Streptococcus, Actinomyces, and Porphyromonas in the nonsmokers. The differences in the phylum Actinobacteria and genus Corynebacterium contributed to various functional differences between smokers and nonsmokers. The difference on oral microbial and composition between E-cigarettes and common tobacco were associated with increased Prevotellaceae and decreased Neisseria. Additionally, smoking cessation could lead to re-establishment of the oral microbiome to that of nonsmokers. Our data demonstrate that E-cigarette smoking had different effects on the structure and composition of the oral microbial community compared to tobacco smoking. However, the short- and long-term impact of E-cigarette smoking on microbiome composition and function needs further exploration.


Asunto(s)
Fumar Cigarrillos , Sistemas Electrónicos de Liberación de Nicotina , Microbiota , Bacterias/genética , Humanos , Microbiota/genética , ARN Ribosómico 16S/genética , Saliva
18.
Science ; 377(6614): 1561-1566, 2022 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-36173865

RESUMEN

The conversion of polyolefins to monomers would create a valuable carbon feedstock from the largest fraction of waste plastic. However, breakdown of the main chains in these polymers requires the cleavage of carbon-carbon bonds that tend to resist selective chemical transformations. Here, we report the production of propylene by partial dehydrogenation of polyethylene and tandem isomerizing ethenolysis of the desaturated chain. Dehydrogenation of high-density polyethylene with either an iridium-pincer complex or platinum/zinc supported on silica as catalysts yielded dehydrogenated material containing up to 3.2% internal olefins; the combination of a second-generation Hoveyda-Grubbs metathesis catalyst and [PdP(tBu)3(µ-Br)]2 as an isomerization catalyst selectively degraded this unsaturated polymer to propylene in yields exceeding 80%. These results show promise for the application of mild catalysis to deconstruct otherwise stable polyolefins.


Asunto(s)
Alquenos , Etilenos , Polietileno , Administración de Residuos , Alquenos/síntesis química , Carbono/química , Catálisis , Etilenos/química , Iridio , Platino (Metal) , Polienos , Polietileno/química , Dióxido de Silicio , Administración de Residuos/métodos
19.
Br Dent J ; 232(4): 253-259, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35217746

RESUMEN

Aim This study aimed to examine the effects of professional oral hygiene care for the prevention of ventilator-associated pneumonia (VAP) and the improvement of oral hygiene among patients in the trauma intensive care unit (TICU).Materials and methods TICU patients who underwent intubation were randomly assigned to either the experimental group (n = 29) or control group (n = 28). The developed professional oral hygiene care protocol was administered to patients in the experimental group every 24 hours. Additionally, data regarding general characteristics, medical history, oral hygiene status, Clinical Pulmonary Infection Score and quantitative polymerase chain reaction were assessed.Results The incidence of VAP differed between the control group (10.58) and experimental group (0) post intervention. Post-admission bedside oral exam scores with significant differences in oral hygiene were observed in the experimental group (in contrast to the control group) from 48 hours onwards (10.69 ± 3.43, p = 0.06). Staphylococcus aureus and Klebsiella pneumoniae exhibited significant differences in count as professional oral hygiene care continued.Conclusions This study suggests a model in which different health care professionals can cooperate to reduce the incidence of VAP and improve oral health conditions.


Asunto(s)
Neumonía Asociada al Ventilador , Humanos , Incidencia , Unidades de Cuidados Intensivos , Salud Bucal , Higiene Bucal/métodos , Neumonía Asociada al Ventilador/epidemiología , Neumonía Asociada al Ventilador/prevención & control
20.
Chin J Dent Res ; 24(4): 231-234, 2021 12 23.
Artículo en Inglés | MEDLINE | ID: mdl-35029094

RESUMEN

The irradiance of powered polymerisation activators for chairside use affects composite resin adhesive curing during the restorative process, whereas radiant accumulated temperature rise relates to clinical safety. Irradiance reduction and high radiant accumulated temperature will compromise the treatment results as there is a lack of curing output efficacy and safety awareness for powered polymerisation activators. Insufficient attention has been paid to the activator's quality control, irradiance attenuation and radiant accumulated temperature excessive temperature rise during its lifetime. The present manuscript has been drafted by the Society of Dental Equipment, Chinese Stomatological Association to fill the quality control gap and guide the quality control process, following tested steps, using a metered radiometer and a thermometer to record the irradiance and radiant accumulated temperature separately. The testing result may indicate the equipment's situation in service and provide information about the irradiance values and performance of the powered polymerisation activator for its usage and maintenance.


Asunto(s)
Resinas Compuestas , Luces de Curación Dental , Ensayo de Materiales , Polimerizacion , Control de Calidad
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