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Twenty Years of Clinical Experience with Cardiac Myxomas: Diagnosis, Treatment, and Follow Up
Tomás Francisco Cianciulli,Alberto Cozzarin,Juan Bautista Soumoulou,María Cristina Saccheri,Ricardo José Méndez,Martín Alberto Beck,Juan Alberto Gagliardi,Jorge Alberto Lax 한국심초음파학회 2019 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.27 No.1
BACKGROUND Cardiac myxomas are the most frequent cardiac tumors. Although histologically benign, in some cases myxomas may be lethal, due to impairment of cardiac dynamics and their thromboembolic potential. The study aimed to assess the clinical presentation of cardiac myxomas and their correlation with echocardiographic features and to describe the perioperative results and long-term outcome of surgically treated patients. METHODS A prospective study of 53 patients with cardiac myxomas who were operated the Hospital Argerich, followed clinically and with echocardiography from 1993 until 2013. All patients underwent echocardiographic studies. RESULTS The patient's mean age was 53 ± 16 years (62.3% were women). The most common findings were dyspnea followed by embolic events. Most tumors were localized in the left atrium (77.4%), mainly in the fossa ovalis (63%). Mean size of the tumors was 4.76 x 3.50 cm. Tumors were generally mobile (88%) and went beyond the valve plane, causing mild mitral or tricuspid valve obstruction (58%) and dilation of the respective atrial chamber. Patients whose tumors were obstructive had higher pulmonary artery systolic pressures (50 vs 33 mmHg p < 0.01). According to the echocardiographic appearance 67% of tumors had a smooth surface and the remaining 32% had a villous surface. All patients with embolic manifestations had tumors with a villous surface. CONCLUSIONS Clinical presentation relates to the ultrasound characteristics of myxomas. Smooth tumors are larger, occur with obstructive symptoms, and benefit from an elective surgery, whereas villous myxomas entailed a high embolic risk and require prompt surgical treatment.
V-notched elements under mode II loading conditions
Alberto Sapora,Pietro Cornetti,Alberto Carpinteri 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.4
We apply the Finite Fracture Mechanics criterion to address the problem of a V-notched structure subjected to mode II loading, i.e., we provide a way to determine the direction and the load at which a crack propagates from the notch tip and express the critical conditions in terms of the generalized stress intensity factor. Weight functions for V-notch emanated cracks available in the literature allow us to implement the fracture criterion proposed in an almost completely analytical manner: the determination of the critical load and the direction of crack growth is reduced to a stationary point problem. A comparison with experimental data presented in the Literature concludes the paper.
Alberto Carpinteri,Pietro Cornetti,Nicola Pugno,David Taylor,Alberto Sapora 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.5
In this paper the results of a series of experimental tests upon three-point bending specimens made of polystyrene and containing re-entrant corners are firstly described. Tests involved different notch angles, different notch depths and finally different sizes of the samples. All the specimens broke at the defect, as expected because of the material brittleness and, hence, the generalized stress intensity factor was expected to be the governing failure parameter. Recorded failure loads are then compared with the predictions provided by a fracture criterion recently introduced in the framework of Finite Fracture Mechanics: fracture is assumed to propagate by finite steps, whose length is determined by the contemporaneous fulfilment of energy balance and stress requirements. This fracture criterion allows us to achieve the expression of the generalized fracture toughness as a function of the tensile strength, the fracture toughness and the notch opening angle. Comparison between theoretical predictions and experimental data turns out to be more than satisfactory.
V-notched elements under mode II loading conditions
Sapora, Alberto,Cornetti, Pietro,Carpinteri, Alberto Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.49 No.4
We apply the Finite Fracture Mechanics criterion to address the problem of a V-notched structure subjected to mode II loading, i.e., we provide a way to determine the direction and the load at which a crack propagates from the notch tip and express the critical conditions in terms of the generalized stress intensity factor. Weight functions for V-notch emanated cracks available in the literature allow us to implement the fracture criterion proposed in an almost completely analytical manner: the determination of the critical load and the direction of crack growth is reduced to a stationary point problem. A comparison with experimental data presented in the Literature concludes the paper.
Carpinteri, Alberto,Cornetti, Pietro,Pugno, Nicola,Sapora, Alberto,Taylor, David Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.32 No.5
In this paper the results of a series of experimental tests upon three-point bending specimens made of polystyrene and containing re-entrant corners are firstly described. Tests involved different notch angles, different notch depths and finally different sizes of the samples. All the specimens broke at the defect, as expected because of the material brittleness and, hence, the generalized stress intensity factor was expected to be the governing failure parameter. Recorded failure loads are then compared with the predictions provided by a fracture criterion recently introduced in the framework of Finite Fracture Mechanics: fracture is assumed to propagate by finite steps, whose length is determined by the contemporaneous fulfilment of energy balance and stress requirements. This fracture criterion allows us to achieve the expression of the generalized fracture toughness as a function of the tensile strength, the fracture toughness and the notch opening angle. Comparison between theoretical predictions and experimental data turns out to be more than satisfactory.
Migration, Jobs, and Real Exchange Rates in the Philippines
( Alberto Chong ) 세종대학교 경제통합연구소 2018 Journal of Economic Integration Vol.33 No.3
This study tests whether exchange rate appreciation due to migration is tempered by the hiring of part-time workers. Quarterly data from 1994 to 2015 for the Philippines are employed. We find that not only increase in remittances, but also increase in migration appreciates real exchange rate. The results also show that underemployment tends to depreciate the exchange rate, which implies that the hiring structure does have a role on the long run real effective exchange rate.
Alberto Mayol 한국라틴아메리카학회 2020 라틴아메리카연구 Vol.33 No.2
The periods of global protest occurring in 2011 and 2019 could actually be the same cycle. In both cases, Chile has been the most disruptive case, despite being (at the same time) an emblematic country for social peace and institutional order throughout the post-dictatorship era, assuming that the Chilean political transition was hailed as an example. The incendiary October of protests in Chile gave rise to a crisis that was unprecedented in the almost thirty years since the end of the dictatorship, and which has led to a questioning which is not only discursive but also operational, with regard to the neoliberal model and the political model, both of which are anchored in the 1980 political Constitution, and which is currently undergoing a formal process for its exchange for a new one born from discussion in a Constitutional Convention chosen for the case. In our opinion, the most important thing lies in understanding the global scope of this particular crisis and noting the strange historical moment in which social unrest in the world seems to have no restraint.
Effects of Hydrocarbon Additions on Gas-liquid Mass Transfer Coefficients in Biphasic Bioreactors
Alberto Reis,Teresa Lopes da Silva,Vitor Calado,Nadia Silva,Rui L. Mendes,Sebastiao S. Alves,Jorge M. T. Vasconcelos 한국생물공학회 2006 Biotechnology and Bioprocess Engineering Vol.11 No.3
The effects of aliphatic hydrocarbons (n-hexadecane and n-dodecane) on the volumetric oxygen mass transfer coefficient (kLa) were studied in flat alveolar airlift reactor and continuous stirred tank reactors (CSTRs). In the flat alveolar airlift reactor, high aeration rates (>2 vvm) were required in order to obtain efficient organic-aqueous phase dispersion and reliable kLa measurements. Addition of 1% (v/v) n-hexadecane or n-dodecane increased the kLa 1.55- and 1.33-fold, respectively, compared to the control (superficial velocity: 25.8 × 10-3 m/s, sparger orifice diameter: 0.5 mm). Analysis of the gas-liquid interfacial area a and the liquid film mass transfer coefficient kL suggests that the observed kLa increase was a function of the media’s liquid film mass transfer. Addition of 1% (v/v) n-hexadecane or n-dodecane to analogous setups using CSTRs led to a kLa increase by a factor of 1.68 and 1.36, respectively (superficial velocity: 2.1 × 10-3 m/s, stirring rate: 250 rpm). These results propose that low-concentration addition of oxygen-vectors to aerobic microbial cultures has additional benefit relative to incubation in purely aqueous media.