bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synchrony Relationships between the Left Ventricle and a left Ventricular Assist Device: An Experimental Study in Pigs
Authors: Heredero Angeles , Perez-Caballero Ramon , Otero Javier , Rodríguez-Martínez Daniel , Quintana-Villamandos Begoña , Rodríguez-Bernal Guillermo , González-Pinto Ángel , Ruiz-Fernandez Manuel , Del Cañizo Juan F. 
Published: April 2012

Background: Synchronization between the left ventricle and a left ventricular assist device (LVAD) may be important for ventricular unloading and coronary perfusion. We assessed the synchrony between cardiac and LVAD cycles by increasing delays in steps of 100 msec throughout the cycle, under conditions of total and partial left ventricular support. Methods: We studied 7 healthy minipigs weighing 30–40 kg. A 60–cc Berlin Heart Excor LVAD was implanted and connected to a BCM 1200 console, making it possible to synchronize the LVAD systole and the EKG signal with a prefixed delay. We recorded hemodynamic parameters (including aortic, pulmonary, and left ventricular pressure) and LVAD flow for each delay. Results: Intraventricular pressure during LVAD systole was minimized with delays of around 40–80% of one cycle. In addition, total flow was higher under these conditions. Conclusions: This study shows that the synchronous mode of LVAD operation is feasible. Moreover, a delay in device contraction until the second half of the cardiac cycle optimizes ventricular unloading and may eventually improve myocardial recovery.
Factors Influencing the Transfer of Porcine Endogenous Retroviruses across the Membrane in Bioartificial Livers
Authors: Shi Xiao-Lei , Han Bing , Tan Jia-Jun , Yuan Xianwen , Zhang Yue , Xiao Jiang-Qiang , Gu Zhong-Ze , Ding Yi-Tao 
Published: April 2012

Objectives: to investigate the factors influencing the transfer of porcine endogenous retroviruses (PERVs) across the membrane in a new bioartificial liver (BAL). Methods: A new BAL containing 2 circuits was constructed using plasma component separators with membrane pore sizes of 10 nm, 20 nm, 30 nm, and 35 nm, or a plasma filter with a membrane pore size of 500 nm. Cocultured cells of porcine hepatocytes and mesenchymal stem cells or single porcine hepatocytes were incubated in the bioreactors, and the BAL worked for 72 hours, with supernatant samples in internal and external circuits collected every 12 hours. PERV RNA, reverse transcriptase (RT) activity, and in vitro infectivity of the supernatant were detected. Results: With the plasma filters, the results of PERV detection were the same in both circuits. With plasma component separators, PERV RNA was found in the external circuits, but no positive RT activity or HEK293 cell infection was found. The time at which the PERV RNA was first detected varied with the pore size of membrane; the larger the membrane pore size was, the earlier the RNA was detected. The PERV RNA level in the external circuits was reduced significantly compared with that in the internal circuits at any detecting time. Conclusions: The plasma component separators with membrane pore size ≤35 nm could significantly reduce the passage of infectious PERVs. And the membrane pore size, the treatment duration, and the viral level in the internal circuit were potential factors influencing the transfer of PERVs across the membrane in a BAL. In addition, a low risk of PERV transmission from porcine hepatocytes to human cells was found.
Computational Modeling of Effects of Mechanical Shaking on Hemodynamics in Hollow Fibers
Authors: Kim Jeong Chul , Garzotto Francesco , Cruz Dinna N. , Clementi Anna , Nalesso Federico , Kim Ji Hyun , Kang Eungtaek , Kim Hee Chan , Ronco Claudio 
Published: April 2012

Introduction: Blood-membrane interaction during hemodialysis develops a secondary protein layer on the dialysis membrane surface, resulting in reduction of hemodialyzer performance. Wall shear stress at the surface of the hollow-fiber membrane is one of the determinant factors able to influence dialysis efficiency. Shaking of hemodialyzer during treatment could increase the wall shear stress of the membrane, which could enhance hemodialyzer performance. Methods: In this study, hemodynamic changes in hollow fibers were analyzed using computational fluid dynamics software for various shaking conditions of hemodialyzer (longitudinal, transverse, rotational motions). Results: Longitudinal motion induced reverse flow, while transverse motion induced symmetric swirling inside the hollow fiber. During rotational motions, nonuniform vortices were developed according to the rotational radius of the hollow fiber. These changes in flow pathlines induced by different shaking profiles increased the relative motion of blood, transmembrane pressure, and wall shear stress on dialysis membrane surfaces. Both longitudinal and transverse shaking profiles showed a linear relationship between shaking velocity (the product of amplitude and frequency) and wall shear stress. Conclusion: Performance of hemodialyzer can be enhanced with simple mechanical shaking motions, and optimal shaking profiles for clinical application can be investigated and predicted with the computational fluid dynamics model proposed in this study.
RESERVOIR MODELING OF DEEPWATER CLASTIC SEQUENCES: MESOSCALE ARCHITECTURAL ELEMENTS, ASPECT RATIOS AND PRODUCIBILITY
Authors: COSSEY STEPHEN P.J. 
Published: April 2012

ABSTRACT
The geoscientist is usually the provider of semi-quantitative data on deepwater clastic architectural elements in the integrated reservoir modeling process. These data can take the form of aspect ratios, vertical and lateral frequencies, or orientations. The arrangement and internal variability of the elements determines the ratio of vertical to horizontal permeability (KV/KH), lateral continuity, and connectivity of the full reservoir model. These three factors ultimately determine the reservoir behavior or producibility. In high net/gross deepwater clastic systems, connectivity of the reservoir is not usually a problem. The size and distribution of architectural elements such as high permeability zones and permeability barriers affect the KV/KH and lateral continuity of reservoirs. Permeability barriers may take the form of shale, concretionary layers, and sandstone that is poorly-sorted. However, in low net/gross systems the lateral continuity of the reservoir “beds” and the presence, absence, and abundance of sedimentary injection features and bioturbation are critical to the connectivity and behavior of the reservoir.
Stochastic models rely on the accuracy of the input variables, where knowledge of the aspect ratios of architectural elements is essential. Stochastic reservoir models of two fields are used as examples of how individual architectural elements might affect the reservoir performance.
FIELD DEVELOPMENT, DEPOSITIONAL MODEL, AND PRODUCTION PERFORMANCE OF THE TURBIDITIC “J” SANDS AT PROSPECT BULLWINKLE, GREEN CANYON 65 FIELD, OUTER-SHELF GULF OF MEXICO
Authors: Holman William E. , Robertson Stephen S. 
Published: April 2012

The Green Canyon 65 Field (GC 65) is located approximately 150 miles southwest of New Orleans, Louisiana in the Gulf of Mexico. The field was developed between 1988 and 1990 from a single 60-slot conventional platform in 1,353 feet of water. GC 65 is expected to produce in excess of 90 MMBO and 170 BCF, 90% of which is contained within the prolific “J” sand sequence. The field’s daily production has consistently exceeded 50,000 BO and 90 MMCFG from 19 producing wells since full scale production began in 1991.
The field lies along the margin of a Plio-Pleistocene salt withdrawal mini-basin. Salt had some influence on “J” sand deposition; however, the primary trap is stratigraphic onlap against a broad lowstand valley. The “J” package consists of numerous interconnected turbidite sheet and channel sands (“J1,” “J2,” “J3,” “J4”). Grain size and bedding style indicate that depositional energy increased upward within the package; the upper surface of the package is defined by multiple erosional unconformities, reflecting sediment bypass as the basin filled.
Integration of multiple 3D seismic surveys, well control, evolving geologic models, produce-while-drilling data, and reservoir simulations optimized the development of Bullwinkle, one of the Gulf of Mexico’s premier oil reservoirs.
Our understanding of the “J” sand reservoirs continues to evolve as production data are incorporated into the subsurface model, reservoir simulator, and compared with seismic/well control. Production has confirmed extensive lateral continuity within individual sands as well as intercommunication between sand members. Aquifer/pressure support is also greater than anticipated. Understanding the reservoir architecture of both the “J” sand package as well as its individual members is considered fundamental in developing an effective reservoir management scheme.
RESERVOIR GEOMETRY AND ARCHITECTURE OF PRODUCTIVE UPPER CRETACEOUS MUD-RICH AND SAND-RICH SUBMARINE-FAN SYSTEMS, SACRAMENTO BASIN, CALIFORNIA
Authors: Nilsen Tor H. , Imperato Douglas P. , Moore Donald W. 
Published: April 2012

Abstract
The Forbes Formation (Santonian and lower Campanian) and Winters Formation (upper Campanian and lower Maastrichtian) are highly productive turbidite reservoirs in the Sacramento forearc basin of northern California. However, their reservoir geometries and architectures differ markedly, chiefly as a result of differences in sediment supply and orientation of sediment input into the basin.
The Forbes Formation has been penetrated by thousands of wells and is productive in about 50 gas fields. It consists, in ascending stratigraphic order, of four major architectural elements that can be distinguished in well logs, seismic-reflection data, and outcrop: (1) a basal massive, concretionary basinwide mudstone, the Dobbins Shale Member, interpreted to be a condensed section deposited during a sea-level highstand; (2) an interval of shale with abundant laterally continuous thin-bedded and fine-grained turbidites interpreted to be a basin-plain succession; (3) a thick interval of mudstone with interbedded sandy and silty turbidites, interpreted to be a mud-rich submarine fan dominated by meandering channel-levee complexes that form the principal reservoir units; and (4) an upper interval of mostly mudstone with laterally discontinuous sandstone bodies incised into south-sloping clinoforms, interpreted to be a muddy slope succession containing abundant sandstone-filled gullies. The deep-marine system was fed by a south-prograding fluvial-dominated delta, the Kione Formation. Both units are overlain by a second basinwide massive mudstone, the Sacramento Shale. The meanderform, ribbon-shaped channel-levee complexes, oriented subparallel to the structural axis of the basin, produce from a variety of traps.
The overlying Winters Formation in the central and southern Sacramento basin has also been penetrated by thousands of wells, and produces from about 40 gas fields. It overlies the Sacramento Shale, interpreted to have been deposited as a condensed section during a long sea-level highstand. The Winters Formation consists, in ascending stratigraphic order, of (1) an interval of mostly shale interpreted to be a basin-plain succession, (2) a complex of pod-shaped sandstone bodies interpreted to have been deposited as sand-rich submarine fans dominated by suprafan-type sandstone bodies that form the principal reservoir units, and (3) muddy slope deposits that contain southwest-dipping clinoforms incised by prominent sandstone-filled submarine canyons. The deep-marine system was fed by a complex of west- and southwest-prograding wave-dominated deltas of the Starkey Formation. The small, pod-shaped submarine fans and pod-shaped suprafan sandstone bodies produce from a variety of traps, and provide a model for other sand-rich, delta-fed submarine-fan systems deposited in restricted basins with modest amounts of shelf accommodation space.
STRATIGRAPHIC AND STRUCTURAL COMPARTMENTALIZATION OBSERVED WITHIN A ‘MODEL TURBIDITE RESERVOIR,’ PENNSYLVANIAN UPPER JACKFORK FORMATION, HOLLYWOOD QUARRY, ARKANSAS
Authors: SLATT ROGER M. , JORDAN DOUGLAS W. , STONE CHARLES G. , WILSON MICHAEL S. 
Published: April 2012

ABSTRACT
Hollywood Quarry is a 600 X 375 X 150 ft. (200 X 125 X 50m) excavation which provides a window into lower Pennsylvanian Jackfork Formation turbidite stratal architecture along the crest of a faulted anticlinal fold. A variety of turbidite facies are present, including: (a) lenticular, channelized sandstones, pebbly sandstones, and conglomerates within shale, (b) laterally continuous, interbedded thin sandstones and shales, and (c) thicker, laterally continuous shales. The sandstone and shale layers are broken by several strikc-slip and reverse faults, with vertical displacements of up to several feet. This combination of facies and structural elements has resulted in a highly compartmentalized stratigraphic interval, both horizontally and vertically, along the anticlinal flexure.
The quarry can be considered analogous to a scaled-down turbidite reservoir. Outcrop gamma-ray logs, measured sections, a fault map, and cross sections provide a database which is analogous to what would be available for a subsurface reservoir. Thus, the quarry provides an ideal outdoor geologic and engineering ‘workshop’ venue for visualizing the potential complexities of a combination stnictural-stratigraphic (turbidite) reservoir. Since all forms of compartmentalization are readily visible in the quarry, problems related to management of compartmentalized reservoirs can be discussed and analyzed first-hand while standing in the quarry, within this ‘model reservoir’. These problems include: (a) the high degree of stratigraphic and structural complexity that may be encountered, even at close well spacings, (b) uncertainty in well log correlations and log-shape interpretations, (c) variations in volumetric calculations as a function of amount of data available, and (d) potential production problems associated with specific ‘field’ development plans.
REGIONAL SEQUENCE STRATIGRAPHIC SETTING OF THE MISSISSIPPI FAN COMPLEX, NORTHERN DEEP GULF OF MEXICO: IMPLICATIONS FOR EVOLUTION OF THE NORTHERN GULF BASIN MARGIN
Authors: Weimer Paul , Dixon Barrett T. 
Published: April 2012

ABSTRACT
The Mississippi Fan Complex is a large submarine fan unit in the deep northern Gulf of Mexico. This complex comprises two distinct submarine fans: the Western and Eastern Fan. Regional mapping of the continental slope and deep basin have further refined the interpretation for the evolution of this area in the Gulf of Mexico. The Western Fan consists of seventeen depositional sequences that were deposited during the late Miocene (5.5 Ma) to the Present. At least seven discrete submarine canyons located in the Ewing Bank, Green Canyon, and Mississippi Canyon lease areas can be traced downslope to their terminus in the equivalent channel-levee systems. The Eastern Fan consists of eight depositional sequences that are coeval to sequences 8-11, 13-16 in the Western Fan. The submarine canyons that fed diese channel-levee systems are located immediately due east of the modem Mississippi bird-foot delta.
Internally, the depositional sequences of the Western and Eastern Fans had similar stratigraphie evolution. Erosional surfaces (sequence boundaries) are at the base of most sequences in the Western Fan amd are overlain by mass transport complexes. In the Eastern Fan, there is generally less erosion at die base of die sequences and mass transport complexes arc generally absent. Channel-levee systems comprise the bulk of the sediments in both fans and can be mapped in both fans. However, the channels in die Eastern Fan are considerably smaller in dimensions than the Western Fan; the eastern channels also have less lateral migration, less sinuosity, and fewer downfan avulsion of channels than the coeval channels in die Western Fan. Large portions of diree sequences in die Eastern Fan consist of in situ slides.
The correlation of die coeval fan sequences between the Eastern and Western Fans lends further evidence of the eustatic control on die timing of these depositional sequences. Compilation of regional work from the slope and shelf areas has also led to the refinement of the age dates of the Mississippi Fan Complex sequences. Sequences 14-17 are now recognized to be 70,000 years to the Present. Sequences 6-13 are interpreted to be 1.9 to 0.40 Ma. Sequences 1-5 are interpreted to be 5.5 to 3.0 Ma. Two major stacked condensed sections are present in the fan: 3.0 to 1.9 Ma, and 0.4 to 0.07 Ma. The development of die condensed sections reflects major avulsions and shifts in the position of the feeding deltaic systems on the continental shelf.
Analysis of Gravity-Flow Depositional Systems From 3-D Seismic Data: Neogene Deposits of the Niger Delta Slope
Authors: Armentrout John M. , Kanschat Katherine A. , Meisling Kristian E. , Tsakma Jerome J. , Antrim Lisa , McConnell Dennis R. 
Published: April 2012

Abstract
Gravity-flow depositional systems of a portion of the Niger delta slope are imaged and documented in seismic amplitude extraction and coherency displays from a large 3-D seismic volume. The displays are extracted immediately above regionally significant sequence boundaries. Interpretation of the 3-D seismic reflection volume demonstrates the strength of combining seismic sequence stratigraphic analysis methodology with the turbidity system architectural element framework.
Each of the gravity-flow systems consists of confined-flow channel-form elements grading down slope into less confined flow, lobe-to sheet-form elements. The Niger slope depositional systems are confined to slope-valley and slope-basin bathymetric lows. The valleys are bounded by densely faulted, structurally complex zones clearly imaged on coherency processed 3-D time slices but poorly imaged on 2-D profiles where they have been previously interpreted as zones of shale diapirism.
Restoration of the valley systems suggests that they had very low relief paleo-bathymetric profiles similar to those observed on the present sea floor. Lower slope basins are “piggy-back” basins above toe thrusts linked to deep-seated gravity-driven, extensional failure of the slope.
Each gravity-flow depositional system consists of three architectural segments: (1) upper slope, small-scale channel elements converging down slope into, (2) singlechannel and nested-channel elements with linear to sinuous map patterns, grading farther down slope into, (3) slope basin lobe and sheet elements. Three types of channel elements are observed: (1) erosional, (2) erosional-depositional, and (3) depositional. The depositional channel elements have geometries strongly suggestive of channel-levee-overbank complexes, indicating that transport must include turbidity-flow processes. In one case, the gradation from mapped channel to lobe to fan elements occurs over less than 1 km (0.65 mi). Within the sheets, lateral accretion of depositional elements suggests compensation sedimentation composed of amalgamated depositional events.
Mapped amplitude patterns of the sequences suggest switching of the inferred sand-prone depositional system from one slope valley to another through time. This is interpreted to reflect both the lateral shifting of the fluvial sediment supply on the shelf, and the local tectonic modification of valley system bathymetry.
The 3-D seismic reflection volume resolves the depositional systems formed by gravity-flow processes through all mapped sequences of the study area. These depositional systems occur within the stratigraphic interval immediately above seismic sequence boundaries and consist of depositional elements known to occur in other modern and ancient turbidite systems.
Geological Heterogeneities and Reservoir Model Based on Facies Architecture of Middle Mississippian Salem Grainstone Shoal, Illinois Basin
Authors: Ahmad Nadeem , Saller Arthur H. 
Published: April 2012

Abstract
Internal architecture, three scales of reservoir heterogeneity, and porosity-permeability compartments can be reconstructed for Middle Mississippian Salem Limestone reservoirs of the Illinois Basin by integrating bedform architecture, depositional fabrics, and trends of porosity development. In sawed quarry walls of south-central Indiana, excellent exposures of the Salem Limestone allow detailed mapping of a wide range of bedforms representative of an extremely dynamic hydrographic regime similar to that of the shoreface zones of siliciclastic shelves. Echinoderm- and bryozoa-rich grainstones and fossiliferous oolitic grainstones are the predominant depositional facies and were deposited as subtidal shoals in an upper shore-face setting. Vertical and spatial relationships of facies and bedforms reveal hierarchies of depositional units and bounding surfaces that have been used to reconstruct four architectural packages (AP’s) of the scale of mesoforms.
AP-I is a channelized mesoform that defines a NNE-SSW intrashoal channel. AP-II is a large storm-deposited sandwave complex that filled the channel. AP-III is a dark-gray grainstone/packstone that grades laterally into packstones and was deposited in a relatively low energy setting. AP-IV consists of oscillatory trough cross-stratified megaripples of oolitic grainstones. Numerous stylolites occur and add to the mesoscale heterogeneity. Together, microfacies, bedforms, and bounding surfaces compartmentalize porosity and permeability and lead to micro- and mesoscale heterogeneities within the mesoform scale architectural packages.
Lessons learned from such outcrop models can be applied to the producing Salem reservoirs in the subsurface. Here, in the distal parts of the inner ramp, the shoal complex is even more compartmentalized because each AP is represented by a “complete” suite of upward-shallowing facies: a basal outer shelf sponge-spicular wackestone, a main shoal grainstone, and an overlying restricted marine lagoonal wackestone. When integrated with mercury-injection capillary-pressure and production data, these packages and respective scales of reservoir heterogeneity help delineate flow units for reservoir characterization and simulation purposes and determine how the reservoir facies will drain during primary and secondary recovery. The results can also be used to reduce uncertainty (geologic risk) during the pre-drill economic assessment, field appraisal, and development phases.