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Tibial-graft fixation methods on anterior cruciate ligament reconstructions: a literature review
( Vitor Luis Pereira ),( João Victor Medeiros ),( Gilvan Rodrigues Silva Nunes ),( Gabriel Taniguti De Oliveira ),( Alexandre Pedro Nicolini ) 대한슬관절학회 2021 대한슬관절학회지 Vol.33 No.-
Introduction: Anterior cruciate ligament (ACL) reconstruction is the most performed orthopedic surgical procedure. The result of ACL reconstructions depends on multiple technical variables, including tension to be applied to the graft for fixation, knee-flexion angle during fixation and the type of fixation to the bone. Objective: To carry out a survey of the literature with the best evidence on these themes. Methods: Literature review about methods of tibial-graft fixation in ACL reconstructions - tension applied at the time of fixation, type of graft fixation, and knee-flexion degree during tibial fixation. Results: Thirty studies on the selected topics were found. Most studies point to graft-tension levels close to 90 N to obtain the best results. Regarding the knee-flexion angle, multiple studies suggest that fixation at a 30° angle would bring superior biomechanical advantages. Regarding the type of implant for fixation, it is not possible to affirm the superiority of one method over another in clinical outcomes. Conclusions: There is no consensus on the best method for tibial fixation of the grafts in ACL reconstructions regarding tension, type of implant and knee-flexion angle. However, the analysis of the studies pointed to certain trends and allowed the drawing of specific conclusions.
Nozzle Design for Combined Use of MQL and Cryogenic Gas in Machining
Octavio Pereira,Adrián Rodríguez,Joaquín Barreiro,Ana Isabel Fernández-Abia,Luis Norberto López de Lacalle 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.4 No.1
Nowadays, the need for not only technically but also environmentally efficient machining processes is increasing. In this context, the reduction of oil emulsion type coolants used during machining of aeronautical engine components supposes a great challenge. In this paper, a novel approach based on the design, optimization and validation of a nozzle adaptor combining cryogenic technology and minimum quantity lubrication systems is proposed. The proposed work also deals with the aim of obtaining a cost-effective process. Thus, CO2 flow and velocity was optimized in this line. Theoretically-based analysis were performed and compared with computational fluid dynamics (CFD) simulations and with real experimental tests as well. Once optimizing these key factors, two nozzle adaptors were designed and simulated by CFD. Different geometries were tested looking for the most efficient design. Finally, to obtain a feasible industrial product, the developed nozzle was tested as a CryoMQL demonstrator comparing with other lubri-coolant techniques during milling Inconel 718. Results show a successful balance between technical and environmental issues using this technology when milling aeronautical alloys.
Simulation of Cryo-cooling to Improve Super Alloys Cutting Tools
Octavio Pereira,Adrián Rodríguez,Amaia Calleja-Ochoa,Ainhoa Celaya,Luis Norberto López de Lacalle,Asier Fernández-Valdivielso,Haizea González 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1
Improve machining processes from an environmental point of view is a hot topic currently. In this line, cryogenics CO 2 is presented as a solution to substitute conventional oil emulsions. However, to be applied industrially, it is needed to control CO 2 flow rate with the aim of reducing CO 2 consumption to reach what it is known as ECO 2 -performance (economy + ecology). Then, despite currently CO 2 cooling technique is used as external coolant, it is needed to improve its use—especially in milling processes—for achieving this goal. In line with this, in this paper is presented the use of CO 2 as tool internal coolant as a solution to optimize its use. For checking its suitability, a study based on computer fluid dynamics with a new cryogenic tool channels design and experimental tests were carried out for analyzing the differences between using CO 2 as internal and external coolant with the aim of improving the use of cryogenic gases during Inconel 718 milling processes. The results show that the use of CO 2 as internal coolant improves the current milling process not only from environmental point of view but also economic and technical, bringing CO 2 cryogenic technology closer to industrial milling conditions.
Natural Products from Garcinia brasiliensis as Leishmania Protease Inhibitors
Ivan O. Pereira,Diego M. Assis,Maria A. Juliano,Rodrigo L.O.R. Cunha,Clara L. Barbieri,Luis V.S. do Sacramento,Marcos J. Marques,Marcelo H. dos Santos 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.6
The infections by protozoans of the genus Leishmania are a major worldwide health problem, with high endemicity in developing countries. The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which cause renal and cardiac toxicity. As part of a search for new drugs against leishmaniasis, we evaluated the in vitro Leishmania protease inhibition activity of extracts (hexanic, ethyl-acetate, and ethanolic) and fukugetin, a bioflavonoid purified from the ethyl-acetate extract of the pericarp of the fruit of Garcinia brasiliensis, a tree native to Brazilian forests. The isolated compound was characterized by using spectral analyses with nuclear magnetic resonance, mass spectroscopy, ultraviolet, and infrared techniques. The ethyl-acetate extract and the compound fukugetin showed significant activity as inhibitors of Leishmania's proteases, with mean (±SD) IC50 (50% inhibition concentration of protease activity) values of 15.0±1.3 μg/mL and 3.2±0.5 μM/mL, respectively, characterizing a bioguided assay. In addition, this isolated compound showed no activity against promastigote and amastigote forms of L. (L.) amazonensis and mammalian cells. These results suggest that fukugetin is a potent protease inhibitor of L. (L.) amazonensis and does not cause toxicity in mammalian or Leishmania cells in vitro. This study provides new perspectives on the development of novel drugs that have leishmanicidal activity obtained from natural products and that target the parasite's proteases.
Self-sustained n-Type Memory Transistor Devices Based on Natural Cellulose Paper Fibers
Martins, Rodrigo,Pereira, Luis,Barquinha, Pedro,Correia, Nuno,Goncalves, Goncalo,Ferreira, Isabel,Dias, Carlos,Correia, N.,Dionisio, M.,Silva, M.,Fortunato, Elvira The Korean Infomation Display Society 2009 Journal of information display Vol.10 No.4
Reported herein is the architecture for a nonvolatile n-type memory paper field-effect transistor. The device was built via the hybrid integration of natural cellulose fibers (pine and eucalyptus fibers embedded in resin with ionic additives), which act simultaneously as substrate and gate dielectric, using passive and active semiconductors, respectively, as well as amorphous indium zinc and gallium indium zinc oxides for the gate electrode and channel layer, respectively. This was complemented by the use of continuous patterned metal layers as source/drain electrodes.
Biochemical Properties of an Extracellular Trehalase from Malbranchea pulchella var. Sulfurea
Marita Gimenez Pereira,Luis Henrique Souza Guimarães,Rosa Prazeres Melo Furriel,Maria de Lourdes,Hector Francisco Terenzi,Joao Atilio Jorge 한국미생물학회 2011 The journal of microbiology Vol.49 No.5
The thermophilic fungus Malbranchea pulchella var. sulfurea produced good amounts of extracellular trehalase activity when grown for long periods on starch, maltose or glucose as the main carbon source. Studies with young cultures suggested that the main role of the extracellular acid trehalase is utilizing trehalose as a carbon source. The specific activity of the purified enzyme in the presence of manganese (680 U/mg protein) was comparable to that of other thermophilic fungi enzymes, but many times higher than the values reported for trehalases from other microbial sources. The apparent molecular mass of the native enzyme was estimated to be 104 kDa by gel filtration and 52 kDa by SDS-PAGE, suggesting that the enzyme was composed by two subunits. The carbohydrate content of the purified enzyme was estimated to be 19% and the pI was 3.5. The optimum pH and temperature were 5.0-5.5 and 55°C, respectively. The purified enzyme was stimulated by manganese and inhibited by calcium ions, and insensitive to ATP and ADP, and 1 mM silver ions. The apparent K_M values for trehalose hydrolysis by the purified enzyme in the absence and presence of manganese chloride were 2.70±0.29 and 2.58±0.13 mM, respectively. Manganese ions affected only the apparent V_(max), increasing the catalytic efficiency value by 9.2-fold. The results reported herein indicate that Malbranchea pulchella produces a trehalase with mixed biochemical properties, different from the conventional acid and neutral enzymes and also from trehalases from other thermophilic fungi.
Javier Mallol,Dirceu Solé,Luis Garcia-Marcos,Nelson Rosario,Viviana Aguirre,Herberto Chong,Marilyn Urrutia-Pereira,Gabriela Szulman,Jurg Niederbacher,Erika Arruda-Chavez,Eliana Toledo,Lillian Sánchez 대한천식알레르기학회 2016 Allergy, Asthma & Immunology Research Vol.8 No.1
Purpose: This study aimed to determine the prevalence and severity of recurrent wheezing (RW) defined as ≥3 episodes of wheezing, risk factors, and treatments prescribed during the first year of life in Latin American infants. Methods: In this international, cross-sectional, and community-based study, parents of 12,405 infants from 11 centers in 6 South American countries (Argentina, Brazil, Chile, Colombia, Peru, and Uruguay) completed a questionnaire about wheezing and associated risk/protective factors, asthma medications, and the frequency of and indications for the prescription of antibiotics and paracetamol during the first year of life. Results: The prevalence of RW was 16.6% (95% CI 16.0-17.3); of the 12,405 infants, 72.7% (95% CI 70.7-74.6) visited the Emergency Department for wheezing, and 29.7% (27.7-31.7) was admitted. Regarding treatment, 49.1% of RW infants received inhaled corticosteroids, 55.7% oral corticosteroids, 26.3% antileukotrienes, 22.9% antibiotics ≥4 times mainly for common colds, wheezing, and pharyngitis, and 57.5% paracetamol ≥4 times. Tobacco smoking during pregnancy, household income per month <1,000 USD, history of parental asthma, male gender, and nursery school attendance were significant risk factors for higher prevalence and severity of RW, whereas breast-feeding for at least 3 months was a significant protective factor. Pneumonia and admissions for pneumonia were significantly higher in infants with RW as compared to the whole sample (3.5-fold and 3.7-fold, respectively). Conclusions: RW affects 1.6 out of 10 infants during the first year of life, with a high prevalence of severe episodes, frequent visits to the Emergency Department, and frequent admissions for wheezing. Besides the elevated prescription of asthma medications, there is an excessive use of antibiotics and paracetamol in infants with RW and also in the whole sample, which is mainly related to common colds.