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Victor Lopez-Lopez,Yusuke Ome,Yusuke Kawamoto,Alvaro Gómez Ruiz,Ricardo Robles Campos,Goro Honda 대한내시경복강경외과학회 2020 Journal of Minimally Invasive Surgery Vol.23 No.1
Since the beginning of laparoscopic liver surgery, resection of the posterosuperior segments has been considered one of the most challenging procedure due to its difficult access. The main drawbacks of the laparoscopic approach to dome lesions are poor visualization, the difficulty of instrumentation and the greater complexity in the control of bleeding. In the evolution of minimally invasive techniques from hybrid techniques to the current purely laparoscopic approaches, the different authors have established gradually the currents indications and surgical techniques to operate these segments with a similar feasibility and safety than open approach. The standardization in the patient position, the use of intercostal trocars, the learning curve in laparoscopic liver surgery, the management of the hepatic blood flow and the refinement of the technique in the extrahepatic and intrahepatic Glissonean pedicle approaches, has allowed to leave behind the initial contraindications about the laparoscopic approach in these segments. In the present review of the literature, the accumulated experience of the different groups in minimally invasive liver surgery together with the technological advances in the different laparoscopic devices have facilitated the resection of tumors in segments 7 and 8 with similar and even better results than open surgery.
Estrada-Angulo, A.,Lopez-Soto, M.A.,Rivera-Mendez, C.R.,Castro, B.I.,Rios, F.G.,Davila-Ramos, H.,Barreras, A.,Urias-Estrada, J.D.,Zinn, R.A.,Plascencia, A. Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.12
Recent findings have shown that microbial nitrogen flow and digestible energy of diets are increased when urea is combined with a slow-release urea (SRU) in diets with a starch to acid detergent fibre ratio (S:F) 4:1. This affect is attributable to enhanced synchrony between ruminal N availability for microbial growth and carbohydrate degradation. To verify the magnitude of this effects on lamb performance, an experiment was conducted to evaluate the effects of combining urea and a SRU in diets containing S:F ratios of 3:1, 4:1, or 5:1 on performance, dietary energetics and carcass characteristics of finishing lambs. For that, 40 Pelibuey${\times}$Katahdin lambs ($36.65{\pm}3kg$) were assigned to one of five weight groupings in 20 pens (5 repetition/treatments). The S:F ratio in the diet was manipulated by partially replacing the corn grain and dried distiller's grain with solubles by forage (wheat straw) and soybean meal to reach S:F ratios of 3:1, 4:1 or 5:1. An additional treatment of 4:1 S:F ratio with 0.8% urea as the sole source of non-protein nitrogen was used as a reference for comparing the effect of urea combination vs. conventional urea at the same S:F ratio. There were no treatment effects on dry matter intake (DMI). Compared the urea combination vs urea at the same S:F ratio, urea combination increased (p<0.01) average daily gain (ADG, 18.3%), gain for feed (G:F, 9.5%), and apparent energy retention per unit DMI (8.2%). Irrespective of the S:F ratio, the urea combination improved the observed-to-expected dietary ratio and apparent retention per unit DMI was maximal (quadratic effect, $p{\leq}0.03$) at an S:F ratio of 4:1, while the conventional urea treatment did not modify the observed-to-expected net energy ratio nor the apparent retention per unit DMI at 4:1 S:F ratio. Urea combination group tended (3.8%, p = 0.08) to have heavier carcasses with no effects on the rest of carcass characteristics. As S:F ratio increased, ADG, G:F, dietary net energy, carcass weight, dressing percentage and longissimus thoracis (LM) area increased linearly ($p{\leq}0.02$). Combining urea and a slow-release urea product results in positive effects on growth performance and dietary energetics, but the best responses are apparently observed when there is a certain proportion (S:F ratio = 4:1) of starch to acid detergent fibre in the diet.
( Sandra Villanueva ),( Fernando Gonzalez ),( Eduardo Lorca ),( Andres Tapia ),( Valentina Lopez G ),( Rocio Strodthoff ),( Francisca Fajre ),( Juan E. Carreno ),( Ricardo Valjalo ),( Cesar Vergara ) 대한신장학회 2019 Kidney Research and Clinical Practice Vol.38 No.2
Background: Chronic kidney disease (CKD) is a growing public health concern, and available treatments are insufficient in limiting disease progression. New strategies, including regenerative cell-based therapies, have emerged as therapeutic alternatives. Results from several groups, including our own, have reported evidence of a supportive role for mesenchymal stromal cells (MSCs) in functional recovery and prevention of tissue damage in murine models of CKD. Prompted by these data, an open pilot study was conducted to assess the safety and efficacy of a single injection of autologous adipose tissue-derived MSCs (AT-MSCs) for treatment of CKD. Methods: AT-MSCs were infused intravenously into six CKD patients at a dose of 1 million cells/kg. Patients were stabilized and followed for one year prior to MSC infusion and one year following infusion. Results: No patients presented with adverse effects. Statistically significant improvement in urinary protein excretion was observed in AT-MSCs transplanted patients, from a median of 0.75 g/day (range, 0.15-9.57) at baseline to 0.54 g/day (range, 0.01-2.66) at month 12 (P = 0.046). The glomerular filtration rate was not significantly decreased post-infusion of AT-MSCs. Conclusion: Findings from this pilot study demonstrate that intravenous infusion of autologous expanded AT-MSCs into CKD patients was not associated with adverse effects and could benefit patients already undergoing standard medical treatment.
Low-Voltage Tunable Pseudo-Differential Transconductor with High Linearity
Juan Antonio Gómez,Melita Pennisi,Antonio Lopez Martin,Ramon González Carvajal,Jaime Ramírez-Angulo,Manuel Pedro Carrasco 한국전자통신연구원 2009 ETRI Journal Vol.31 No.5
A novel tunable transconductor is presented. Input transistors operate in the triode region to achieve programmable voltage-to-current conversion. These transistors are kept in the triode region by a novel negative feedback loop which features simplicity, low voltage requirements, and high output resistance. A linearity analysis is carried out which demonstrates how the proposed transconductance tuning scheme leads to high linearity in a wide transconductance range. Measurement results for a 0.5 μm CMOS implementation of the transconductor show a transconductance tuning range of more than a decade (15 μA/V to 165 μA/V) and a total harmonic distortion of -67 dB at 1 MHz for an input of 1 Vpp and a supply voltage of 1.8 V.
Suppression of cooling by strong magnetic fields in white dwarf stars
Valyavin, G.,Shulyak, D.,Wade, G. A.,Antonyuk, K.,Zharikov, S. V.,Galazutdinov, G. A.,Plachinda, S.,Bagnulo, S.,Machado, L. Fox,Alvarez, M.,Clark, D. M.,Lopez, J. M.,Hiriart, D.,Han, Inwoo,Jeon, Young Nature Publishing Group, a division of Macmillan P 2014 Nature Vol.515 No.7525
Isolated cool white dwarf stars more often have strong magnetic fields than young, hotter white dwarfs, which has been a puzzle because magnetic fields are expected to decay with time but a cool surface suggests that the star is old. In addition, some white dwarfs with strong fields vary in brightness as they rotate, which has been variously attributed to surface brightness inhomogeneities similar to sunspots, chemical inhomogeneities and other magneto-optical effects. Here we describe optical observations of the brightness and magnetic field of the cool white dwarf WD 1953-011 taken over about eight years, and the results of an analysis of its surface temperature and magnetic field distribution. We find that the magnetic field suppresses atmospheric convection, leading to dark spots in the most magnetized areas. We also find that strong fields are sufficient to suppress convection over the entire surface in cool magnetic white dwarfs, which inhibits their cooling evolution relative to weakly magnetic and non-magnetic white dwarfs, making them appear younger than they truly are. This explains the long-standing mystery of why magnetic fields are more common amongst cool white dwarfs, and implies that the currently accepted ages of strongly magnetic white dwarfs are systematically too young.
A STUDY OF THE PHOTOMETRIC VARIABILITY OF THE PECULIAR MAGNETIC WHITE DWARF WD 1953-011
Valyavin, G.,Antonyuk, K.,Plachinda, S.,Clark, D. M.,Wade, G. A.,Machado, Lester Fox,Alvarez, M.,Lopez, J. M.,Hiriart, D.,Han, Inwoo,Jeon, Young-Beom,Bagnulo, S.,Zharikov, S. V.,Zurita, C.,Mujica, R. IOP Publishing 2011 The Astrophysical journal Vol.734 No.1
<P>We present and interpret simultaneous new photometric and spectroscopic observations of the peculiar magnetic white dwarf WD 1953-011. The flux in the V-band filter and intensity of the Balmer spectral lines demonstrate variability with the rotation period of about 1.45 days. According to previous studies, this variability can be explained by the presence of a dark spot having a magnetic nature, analogous to a sunspot. Motivated by this idea, we examine possible physical relationships between the suggested dark spot and the strong-field magnetic structure (magnetic 'spot' or 'tube') recently identified on the surface of this star. Comparing the rotationally modulated flux with the variable spectral observables related to the magnetic 'spot,' we establish their correlation and therefore their physical relationship. Modeling the variable photometric flux assuming that it is associated with temperature variations in the stellar photosphere, we argue that the strong-field area and dark, low-temperature spot are comparable in size and located at the same latitudes, essentially overlapping each other with a possible slight longitudinal shift. In this paper, we also present a new, improved value of the star's rotational period and constrain the characteristics of the thermal inhomogeneity over the degenerate's surface.</P>
M. Cortazar,L. Santamaria,G. Lopez,J. Alvarez,M. Amutio,J. Bilbao,M. Olazar 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-
The performance of Fe/olivine catalysts was tested in the continuous steam gasification of sawdust in abench scale plant provided with a fountain confined conical spouted bed reactor at 850 C. Olivine wasused as catalyst support and loaded with 5 wt%Fe. The activity and stability of the catalyst was monitoredby nitrogen adsorption-desorption, X-rayfluorescence spectroscopy, temperature programmedreduction, X-ray diffraction and X-ray photoelectron spectroscopy techniques, which were conductedbefore and after the runs. The fountain confined conical spouted bed performs well in the biomass steamgasification with primary catalysts. In fact, this reactor allows enhancing the gas-solid contact, andtherefore the catalytic activity by avoiding the elutriation offine catalyst particles. The uncatalysedefficiency of the gasification process, assessed based on the gas production and composition, H2production, tar concentration and composition, and carbon conversion efficiency, was considerabyimproved on the Fe/olivine catalyst, with tar reduction being especially remarkable (to 10.4 g Nm 3). After 140 min on stream, catalyst deactivation was particularly evident, as tar concentration increased to19.9 g Nm 3 (90% of that without catalyst). However, Fe/olivine catalyst was still active for WGS and CH4steam reforming reactions, with gas and H2 productions being 1.35 Nm3 kg 1 and 5.44 wt%, respectively. Metal iron oxidation to Fe3O4 caused catalyst deactivation, as the reaction environment shifted fromoxidizing to reducing conditions due to operational limitations.
Lee, S.,Iyore, O.D.,Park, S.,Lee, Y.G.,Jandhyala, S.,Kang, C.G.,Mordi, G.,Kim, Y.,Quevedo-Lopez, M.,Gnade, B.E.,Wallace, R.M.,Lee, B.H.,Kim, J. Pergamon Press ; Elsevier Science Ltd 2014 Carbon Vol.68 No.-
The performance of graphene field effect transistors fabricated on flexible substrates is easily degraded by deformation, delamination and shrinkage during the device fabrication. Multiple thermal annealing on graphene devices could be performed without damages to the flexible substrate using a rigid supporting substrate, poly(dimethylsiloxane) coated Si, holding the flexible substrate during the device fabrication. As a result, a very high performance including electron mobility ~12980 and hole mobility ~9214cm<SUP>2</SUP>/Vs could be achieved. The performance enhancement is attributed to the effective removal of polymer residues using a high temperature vacuum anneal and a reduced interfacial reaction between the graphene and the hydrophobic flexible substrate.