bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conocimientos, actitudes y sintomatología referida a la menopausia en mujeres de un distrito rural de la sierra peruana.
Authors: LLANOS TEJADA Felix Konrad 
Published: March 2016

Objetivos: Determinar los conocimientos, actitudes y sintomatología frente a la menopausia en las mujeres de un distrito rural de la sierra peruana. Material y Métodos: Se realizó una encuesta clínica a las mujeres de 40 a 50 años de edad del distrito de La Ramada sobre conocimiento, actitudes y sintomatología de la menopausia. Resultados: Se evaluó un total de 97 mujeres de 40 a 50 años de edad, quienes definieron la menopausia como un proceso natural (90.72%), presentando actitudes de alivio (85.56%) y frustración (69.07%) mayoritariamente, con sintomatología prioritaria de cambios vasomotores (44.36%). El 38.14% refirió alteraciones en el estilo de vida por la sintomatología propia de la menopausia. Conclusiones: Aceptación de la menopausia como un proceso normal, con cambios en el estilo de vida en casi un tercio de pacientes.
Características de la demanda de capacitación en personal administrativo en hospitales nacionales de Lima y Callao.
Authors: GARCÍA AHUMADA Félix Santiago , LLANOS CUENTAS Alejandro 
Published: March 2016

Objetivos: Determinar algunas características de la demanda de capacitación del personal administrativo de los hospitales nacionales del Ministerio de Salud en Lima y Callao correspondientes al año 2003. Materiales y Métodos: Se elaboró y validó un instrumento para la recolección de datos, el mismo que fue completado por las 224 personas que conformaron la muestra. Resultados: Los temas de capacitación más demandados fueron, en planificación, plan operativo; en economía, gestión económico financiera; en logística, gestión logística; en personal; gestión de personal; y en estadística, indicadores estadísticos. El lugar preferido para la capacitación fue el mismo establecimiento hospitalario, el horario fue el vespertino de 14:00 a 17:00 horas (41,07%), y la mayoría de personas prefieren no invertir ningún monto de dinero en capacitación (70,53%). Conclusiones: Estos hallazgos evidencian la existencia de una demanda de capacitación determinada en el personal administrativo en este grupo de hospitales, demanda que debe ser cubierta.
Abordaje combinado cervical y torácico para casos selectos de bocio retroesternal.
Authors: Vasquez Kobashigawa Julio Cesar , Montesinos Mosqueira Efrain , Castillo De La Cadena Luis , Rojas Pena Luis , Peralta Rodríguez Julio , Saavedra Leveau Jose 
Published: March 2016

Se presentan dos casos de bocio retroesternal que fueron resecados a través de incisión cervical y esternotomía mediana. Se discuten las alternativas para el abordaje quirúrgico y se hace una revisión de la literatura.
Enfermedad de Graves: Presentación tardía de síndrome de reconstitución inmune en VIH/ SIDA: Reporte de casos y revisión de la literatura.
Authors: Pinto Valdivia Miguel Eduardo , Iglesias Quilca David , Corigliano Carrillo Sandro , Maguiña Vargas Ciro , Echevarria Zarate Juan , Villena Chavez Jaime , Seas Ramos Carlos 
Published: March 2016

Se reportan dos casos de enfermedad de Graves relacionados con sindrome de Reconstitución Inmune en dos pacientes infectados con VIH luego de iniciar la terapia antiretroviral de gran actividad (TARGA). Se revisaron las historias clínicas de los pacientes y se hizo una revisión bibliográfica. Dos pacientes con historia de infección por VIH desarrollaron pérdida de peso, taquicardia, tremor en la manos y diarrea, luego de 30 y 48 meses después de iniciado tratamiento TARGA con zidovudina, lamivudina y atazanavir. Al momento de desarrollar este problema su conteo de células CD4 estaba en rangos de normalidad y su carga viral estaba en niveles indetectables. En el examen Físico se detectó un aumento de volumen de la glándula tiroides. Los niveles de tirotropina estaban suprimidos y los niveles de tiroxina libre elevados; se detectó niveles positivos de anticuerpos anti-TPO. Ambos pacientes mejoraron con el tratamiento metimazol y atenolol. La enfermedad de Graves ha sido reportada como complicación inusual en pacientes VIH como reconstitución Inmune luego del inicio de TARGA. Estos dos pacientes muestran un cuadro compatible.
Síndrome de Apneas Hipopneas del Sueño. ¿Asesino silencioso? Revisión de la literatura.
Authors: Rey De Castro Mujica Jorge 
Published: March 2016

El Síndrome de Apneas-Hipopneas del Sueño (SAHS) consiste en la aparición de episodios recurrentes que limitan el paso del aire durante el sueño, como consecuencia de una alteración anatómico-funcional de la vía aérea superior que conduce a su colapso, provocando descensos de la saturación de oxihemoglobina y microdespertares dando lugar a un sueño no reparador, somnolencia diurna excesiva, trastornos neuropsiquiátricos, respiratorios y cardiacos (1,2). Sin duda, el SAHS no tratado está asociado a mala calidad de vida, compromiso neurocognitivo (3-5), hipertensión arterial (6-11), enfermedad vascular cerebral (12-14), y coronaria (15-17), así como accidentes de tránsito durante la conducción debido a somnolencia (18-22).
TF-1 Cell Proliferation Assay Method for Estimating Bioactivity of Nerve Growth Factor
Authors: Ma Lingyan , Zou Yufei 
Published: March 2016

<p>Nerve growth factor (NGF) is a neurotrophic factor responsible for the differentiation and survival of sympathetic and sensory neurons as well as selective populations of cholinergic neurons. The MTT assay is to add the chromogenic substance MTT after the NGF has stimulated the TF1 cells, to conduct a colorimetric analysis on the micro plate reader, then to compare the results with a standard curve to arrive at the biological activity of the test substance. To use the MTT assay to measure the biological activity of the NGF, it is easy to handle, with good and reliable results, repeatable and with no impact of the human factors.</p>
A Novel Viscosity Reduction Plant-Based Diluent for Heavy and Extra-Heavy Oil
Authors: Afra Salar , Nasr-El-Din Hisham , Socci Dan , Cui Zheng 
Published: March 2016

Abstract
The production and transportation of heavy and extra-heavy crude oil are two of the paramount concerns in the oil industry due to the difficulties associated with heavy crude oil high viscosity. One of the most efficient techniques to improve the recovery and the transportability of such oil is to reduce its viscosity through dilution that can be applied solely or via thermal methods.
In the present work, a new type of plant-based diluent is proposed, and its efficacy in heavy oil viscosity reduction for different concentrations, temperatures and shear rates is studied. Various concentrations of diluent, ranging from 5 to 25 wt%, are added to heavy-oil samples with different concentrations of asphaltene and viscosity, ranging from 48000 to 65000 cp in ambient temperature. A rotational viscometer was then employed to the measure viscosity of the prepared samples at the temperature range of 70 to 190°F and a shear rate of 3 to 50 s−1.
The application of the proposed diluent led to promising results in that in caused the viscosity of the heavy oil samples to reduce by 93% in 75°F and 85% in 190°F with 20 wt% of diluent. To compare the performance of the proposed solvent and the common viscosity-reducing solvents, heavy oil samples were diluted with xylene and toluene with the same concentrations. Results indicated that the application of proposed diluent outperformed all of the commonly used solvents in terms of decreasing viscosity. The application of 20 wt% of the proposed diluent led to a 93% viscosity reduction of the heavy oil samples, which is 15% more than efficiency of adding the same concentration of toluene.
The proposed diluent is a plant-based, non-hazardous substitute to the conventional hazardous diluents, e.g., xylene or toluene, that provides more efficient viscosity reduction compared to its conventional alternatives. Its flashpoint is higher than that of light crude resulting in less evaporation at high temperatures thus a longer period of reduced viscosity can be obtained. Furthermore, due to its high flashpoint, the proposed diluent can be employed in thermal methods more efficiently.
Research and Application of Micron-Size Polyacrylamide Elastic Microspheres as a Smart Sweep Improvement and Profile Modification Agent
Authors: Yao Chuanjin , Xu Xiaohong , Wang Dan , Lei Guanglun , Xue Shifeng , Hou Jian , Cathles Lawrence M. , Steenhuis Tammo S. 
Published: March 2016

Abstract
Micron-size polyacrylamide elastic microspheres (MPEMs) are a smart sweep improvement and profile modification agent, which can be prepared controllably on the ground through inverse suspension polymerization using acrylamide crosslinked with an organic crosslinker. MPEMs can tolerate high temperature of 90 °C, high salinity of 20000 mg/L and wide pH value range of 4.0–10.3. MPEMs suspension almost has no corrosion effect on the injection pipeline and equipment. MPEMs can suspend in produced water easily and be pumped into formation at any rate. More importantly, MPEMs can reach the designed size after hydration swelling in oil formation and a reliable blockage can be formed; MPEMs can deform elastically and move forward step by step to realize a moveable sweep improvement and profile modification process in reservoirs. The pore-scale visualization experiment shows that there are four migration patterns for MPEMs transport in porous media and they are smooth passing, elastic plugging, bridge plugging and complete plugging. MPEMs can deform depending on their elasticity and pass through these pore-throats. Parallel-sandpack physical modeling experiment under the simulated reservoir conditions shows that MPEMs mainly enter into and plug high permeability layer whose permeability is reduced from 3.642 μm2 to 0.546 μm2, and almost do not clog low-permeability layer whose permeability is reduced from 0.534 μm2 to 0.512 μm2. Field application results of MPEMs treatment in a serious heterogeneous, high temperature and high salinity reservoir show that MPEMs can effectively improve swept volume and displacement efficiency. Because of the excellent properties, MPEMs treatment will become a cost-effective method for sweep improvement and profile modification to serious heterogeneous, high temperature and high salinity reservoirs with fractures and channels.
Benefits of A Mixed CO2/CO/N2 Gas for EOR
Authors: Trost P. B. 
Published: March 2016

Abstract
Achieving maximum oil recovery utilizing CO2 has limitations when operating at, or very close, to the Minimum Miscibility Pressure (MMP) of the CO2 in the oil. A modular source of CO2 would allow Enhanced Oil Recovery (EOR) flooding of "stranded" and shallow reservoirs. Unfortunately, modular sources of CO2 production often include CO and N2 mixed with the CO2. Thus, testing for EOR application of a mixed gas-containing CO2, N2, and CO was initiated.
Bench scale testing using Rising Bubble Apparatus (RBA), Slim Tubes, and linear core flood have been conducted on oils ranging from 16-42° gravities having viscosities of 0.5-280 cp. All tests were conducted at reservoir temperatures and pressures. CO, being a strong reducing agent, was further tested on reservoir rock containing swelling clays with hydrated ferric hydroxides. Due to the apparent reduction of the ferric hydroxide, and the liberation of its water of hydration, an increase in matrix permeability and clay stabilization, was observed.
For most oils tested, the CO2/CO mixture increased rate of oil recovery by 2-3X, using only 50-60% as much gas/bo as compared to pure CO2. Recovery factors of 80%, at immiscible pressures 30-40% below CO2 MMP, were achieved. Addition of 15% N2 (v/v) to the CO2/CO mixture did not impair oil recovery. Interfacial testing (IFT) of oils, using pure CO, demonstrated a lowering of the IFT. RBA testing of asphaltine-rich heavy oils has shown that a mixture of CO2/CO dissolves into the oil at a far faster rate than either CO2 or CO individually and faster than the sum of both individual gases. A similar test using non-asphaltine type oils did not display this unique characteristic. Slim tube testing suggests that CO facilitates the mobilization of asphaltine-rich heavy oils and lowers viscosity. A linear corefloods of a reservoir containing 5% smectite + illite/smectite + and chlorite demonstrated a 275% increase in matrix permeability. Packed column tests, containing quartz sand and bentonite, demonstrated up to 300-900% increase in permeability in the presence of CO.
Thus a method to recover oil faster, from stranded reservoirs, at pressures below MMP, using significantly less gas, appears possible. In addition the use of CO, either alone or in combination with CO2 and/or N2, has been shown to increase matrix permeability. Such a gas mixture may be beneficial to achieving low pressure EOR from shallow, "stranded" reservoirs, non-conventional shale oil reservoirs, and viscous, heavy oil reservoirs at low temperatures. Incorporation of CO, or CO2/CO, in a frac fluid, or alternately as a post frac cleanup for shale oil and gas applications appears to warrant investigation.
Studies on Viscoelastic Surfactants for its Potential EOR Application in the Low Permeability Reservoirs
Authors: Zhu Youyi , Fan Jian , Liu Xiaoxia , Li Jianguo 
Published: March 2016

Abstract
Chemical flooding technology is one of the effective enhanced oil recovery (EOR) methods for high water cut sandstone reservoirs with either medium and/or high permeability. Because of the small pore throat radius in the pore medium of low permeability reservoir, high molecular weight polymers cannot be injected in the low permeability reservoir. Therefore, many traditional chemical floodings (such as polymer flooding, alkali-surfactant-polymer (ASP) flooding and surfactant-polymer (SP) flooding) cannot be effectively applied in this case. Small-molecule viscoelastic surfactant (VES) has special rheological properties in porous medium. It showed both viscosified function and reduction of oil/water interfacial tension (IFT) performances under certain conditions, thereby providing the possibility of IOR/EOR potential application in low permeability reservoirs.
Most of reservoirs in Jilin Oilfield belong to low permeability reservoirs with permeability of around 50 mD in average. The recovery percent of reserves in Fuyu was only 23% by water flooding with water cut as high as 93%. A candidate EOR technique with chemical flooding has been proposed. Studies on VES flooding EOR methods targeting this reservoir condition were conducted. The rheological property, IFT property, viscosifying ability of VES and core flooding experiments of VES system were studied.
From VES screening experiment, a type of zwitterionic betaine surfactant with long carbon chain was selected. It showed viscosifying behavior, shear thinning property and low IFT performances at reservoir conditions. VES of EAB solutions showed a good viscosifying action at low surfactant concentration. Moreover, based on its shear thinning property under the wide shear rate conditions, VES exhibited a good injectivity performance. IFT between crude oil and formation water with EAB was 10−3-10−2 mN/m order of magnitudes. The results could be obtained at the concentration ranges of surfactants from 0.1wt% to 0.4wt%. Ultralow IFT (10−3 mN/m order of magnitudes) could be obtained in the presence of co-surfactants or alkalis (such as sodium carbonate). Core flooding experiments of VES flooding showed that the incremental oil recovery factors could reach up to 13%-17% over conventional water flooding at Fuyu reservoir conditions. Test results indicated that VES flooding might become a promise alternative EOR method for low permeability reservoir after water flooding.
In contrast to the complexity of ASP/SP combination system, VES flooding could avoid chromatographic effects in the reservoir based on their simple formula (single surfactant compound). This new chemical flooding technique might have a great potential for EOR application in the low permeability reservoirs.
Nuclear Magnetic Resonance Study on Mechanisms of Oil Mobilization in Tight Reservoir Exposed to CO2 in Pore Scale
Authors: Wang Haitao , Lun Zengmin , Lv Chengyuan , Lang Dongjiang , Pan Weiyi , Luo Ming , Wang Rui , Chen Shaohua 
Published: March 2016

Abstract
Nuclear magnetic resonance (NMR) was used to investigate the exposure between CO2 and matrix with permeability of 0.218 mD at 40 °C and 12 MPa. Before NMR experiment, the core was saturated with oil. To investigate the effects of exposure time on EOR, the saturated core was exposed to CO2 and T2 test was continuously performed with NMR system until the obtained T2 spectrum was unchanged. After the first exposure, CO2 and matrix reached equilibrium state. The second exposure started when CO2 injection was under a constant pressure of 12 MPa and at a constant rate to keep fresh CO2 in system. The procedure of T2 test was unchanged. The third and fourth exposures were conducted in sequence. The results showed that (1) Oil in all pores can mobilize as exposure time increases. (2) The recovery is 46.6% for oil in pores with the diameter of pore larger than 1 μm, this result is higher than the recovery (12.8%) for oil in pores with the diameter of pore smaller than 1 μm. (3) Recovery can be divided into two stages according to the exposure time: a fast-growing stage and a slow-growing stage. (4) Initially, the oil exists in pores with maximum radius of 21 μm in the originally saturated core. After CO2 injection, oil flows to pores with radius greater than 21 μm, suggesting that oil in tight matrix "diffuses" to the surface of core with exposure between CO2 and matrix. (5) The final recoveries of 1st, 2nd, 3rd, 4th exposure experiments are 23.7%, 7.2%, 2.6% and 1.5%, respectively.
A New Screening Test for Chemical Improved Oil Recovery in Carbonate Formations
Authors: Dalmazzone C. , Mouret A. , Behot J. , Norrant F. , Gautier S. , Argillier J.-F. , Chabert M. 
Published: March 2016

Abstract
A majority of the worldwide oil reserves is contained in carbonate reservoirs. Most of these reservoirs are naturally fractured and produce less than 10% of the oil in place during the primary recovery operations. It is noteworthy that this particularly low recovery ratio is essentially due to a low permeability associated to an intermediate or preferentially oil wettability. Consequently, the recovery of residual oil from these specific reservoirs is a great challenge. Changing the wettability from oil wet to preferentially water wet by using chemicals is one of the EOR technique that may be advantageously used to enhance the production rate. This chemical treatment consists in injecting an aqueous solution of surfactants or chemical additives to increase the water wettability and favour spontaneous imbibition into the porous matrix. We present a new test allowing a fast screening of aqueous solutions of chemicals that may be used to improve oil recovery from carbonate reservoirs. The test consists in depositing a drop of aqueous solution on a porous carbonate slice that has been treated to be preferentially oil wet before being put into dodecane. The evolution of the drop profile is then monitored as a function of time by means of a camera, which permits a simultaneous measurement of the interfacial tension between oil and water, contact angle between the water drop and the porous matrix and spontaneous imbibition. Various types of non-ionic and anionic surfactants belonging to different families have been tested and ranked to identify the best candidates among these chemicals. Finally, a Nuclear Magnetic Resonance technique was used to follow spontaneous imbibitions of selected candidates in miniplugs representative of the carbonate slices used in the screening test. NMR's results confirmed the classification issued from the fast screening test.
Effects of Low-Salinity Waterflooding on Capillary Pressure Hysteresis
Authors: Wang Xiao , Alvarado Vladimir 
Published: March 2016

Abstract
Low-salinity waterflooding has been portrayed as an effective enhanced-oil recovery technology. Despite compelling laboratory and field evidence of its potential, the underlying mechanisms still remain controversial. In this study, the enhanced-oil recovery mechanisms are investigated considering a distinct interfacial effect, i.e. water-crude oil interfacial viscoelasticity, through analysis of capillary hysteresis. An experimental setup with an oil-wet and a water-wet media on each end face of the core sample was utilized to capture capillary and rock electrical properties hysteresis. Moreover, new improvements over the traditional quasi-static porous plate method were implemented to accelerate measurements. Two experiments were conducted on Minnelusa formation rock samples and TC crude oil, at low temperature (30 °C) and without any significant aging as to minimize wettability alteration. Two core plugs were flooded with high-salinity and low-salinity brines, separately. It is found that the dynamic-static method with a ceramic disk, i.e. a combination of continuous injection in drainage and stepwise quasi-static method in imbibition on short 1" long core samples, allows one to capture the correct envelopes of the capillary pressure curves and save ~ 30% of the total time; a thin membrane is anticipated to save ~90% with respect to traditional quasi-static porous plate method. The capillary hysteresis experiments at low temperature prove that low-salinity brine is able to suppress capillary hysteresis. This is attributed to the formation of a more visco-elastic brine-crude oil interface upon exposure to low-salinity brine, leading to a more continuous oil phase. In addition, we show that wettability plays an essential role on electrical resistivity and the more oil-wet, the more hysteresis occurs, namely that resistivity values in imbibition are higher than those in drainage. The findings in this paper demonstrate that low-salinity waterflooding can still increase oil recovery even in the absence of wettability alteration.
Simulation of Surfactant-Polymer Floods with a Novel Microemulsion Equation of State
Authors: Khorsandi Saeid , Qiao Changhe , Johns Russell T. , Torrealba Victor A. 
Published: March 2016

Abstract
Reservoir simulation is a valuable tool for assessing the potential success of enhanced recovery processes. Current chemical flooding reservoir simulators, however, use Hand's model to describe surfactant-oil-brine systems even though Hand's model is not predictive, and can fit only a limited data set. Hand's model requires the tuning of multiple empirical parameters using experimental data that usually consist of salinity scans at constant reservoir temperature and atmospheric pressure. Given experimental data supporting the change in microemulsion phase behavior with key formulation properties (e.g. temperature, pressure, salinity, EACN, and overall composition), there is a need for an improved model that can capture changes in these relevant parameters at the reservoir scale. The recent EOS proposed for microemulsion phase behavior (Ghosh and Johns 2014, 2016), which is based partially on the hydrophyllic-lypophyllic difference and net average curvature model (HLD-NAC, Acosta et al. 2003), has been supported by numerous experimental data and provides a more mechanistic phase behavior model than the Hand's model.
In this paper, the EOS model with the extension to two-phase regions is incorporated for the first time into the chemical flooding simulators, UTCHEM, and our new in-house simulator PennSim. Hand's model is only used for comparison purposes, and is no longer needed even for flash calculations in the type II- and type II+ regions. The results show excellent agreement between UTCHEM and PennSim both in composition space and for composition/saturation profiles. Further, the HLD-NAC based EOS model and Hand's models are fitted to the same experimental data and the results of these simulations are nearly identical when variations of salinity, pressure and temperature are small. For large gradients, the results of the physics-based EOS deviates from Hand's model, and shows it is critical to incorporate these gradients in recovery predictions at large scale.