bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of model complexity and problem formulation on the forces in the knee calculated using optimization methods
Authors: Hu Chih-Chung , Lu Tung-Wu , Chen Sheng-Chang 
Published: March 2013

Abstract

Background
Predictions of the forces transmitted by the redundant force-bearing structures in the knee are often performed using optimization methods considering only moment equipollence as a result of simplified knee modeling without ligament contributions. The current study aimed to investigate the influence of model complexity (with or without ligaments), problem formulation (moment equipollence with or without force equipollence) and optimization criteria on the prediction of the forces transmitted by the force-bearing structures in the knee.

Methods
Ten healthy young male adults walked in a gait laboratory while their kinematic and ground reaction forces were measured simultaneously. A validated 3D musculoskeletal model of the locomotor system with a knee model that included muscles, ligaments and articular surfaces was used to calculate the joint resultant forces and moments, and subsequently the forces transmitted in the considered force-bearing structures via optimization methods. Three problem formulations with eight optimization criteria were evaluated.

Results
Among the three problem formulations, simultaneous consideration of moment and force equipollence for the knee model with ligaments and articular contacts predicted contact forces (first peak: 3.3-3.5 BW; second peak: 3.2-4.2 BW; swing: 0.3 BW) that were closest to previously reported theoretical values (2.0-4.0 BW) and in vivo data telemetered from older adults with total knee replacements (about 2.8 BW during stance; 0.5 BW during swing). Simultaneous consideration of moment and force equipollence also predicted more physiological ligament forces (< 1.0 BW), which appeared to be independent of the objective functions used. Without considering force equipollence, the calculated contact forces varied from 1.0 to 4.5 BW and were as large as 2.5 BW during swing phase; the calculated ACL forces ranged from 1 BW to 3.7 BW, and those of the PCL from 3 BW to 7 BW.

Conclusions
Model complexity and problem formulation affect the prediction of the forces transmitted by the force-bearing structures at the knee during normal level walking. Inclusion of the ligaments in a knee model enables the simultaneous consideration of equations of force and moment equipollence, which is required for accurately estimating the contact and ligament forces, and is more critical than the adopted optimization criteria.
Antioxidant properties of Pelargonium graveolens L’Her essential oil on the reproductive damage induced by deltamethrin in mice as compared to alpha-tocopherol
Authors: Ben Slima Ahlem , Ali Manel Ben , Barkallah Mohamed , Traore Al Ibrahim , Boudawara Tahia , Allouche Noureddine , Gdoura Radhouane 
Published: March 2013

Abstract

Background
Exposure to the pyrethroid pesticide deltamethrin has been demonstrated to exert a wide range of effects on non-targeted organisms. The beneficial effects of geranuim essential oil (EO) as an antioxidant has been assessed in deltamethrin (DL) orally administered mice by studying whether the reprotoxicity caused by deltamethrin can be effectively combated with the geranium oil and the effects were compared to vitamin E, as the standard reference drug.

Result
Sixty male albino mice were divided into six equal groups: a control group, a group of mice was given deltamethrin (5 mg/kg b.w.), two groups were administered deltamethrin after having given geranium essential oil (67 mg/kg b.w.) or vitamin E (Vit E) (100 mg/kg b.w.), and two groups received only EO of geranium or Vit E. When compared to control, a dose of deltamethrin 5 mg/kg/day causes a decrease in the epididymal sperm count motility and viability and an increase in the number of abnormal morphology in spermatozoa. DL-exposed mice showed a significant increase of lipid peroxidation (LPP) in the testis compared to control animals.

Conclusion
Essential oil of geranium prevented testicular oxidative damage explored by reduced LPP and improved total sperm motility, viability and morphology in mice spermatozoa. Our study showed a positive influence of geranium essential oil in the animal male reproductive system similar than that of Vit E.
The potential role of microfilaments in host cells for infection with infectious spleen and kidney necrosis virus infection
Authors: Jia Kun-tong , Liu Zhao-yu , Guo Chang-jun , Xia Qiong , Mi Shu , Li Xiao-Dong , Weng Shao-ping , He Jian-guo 
Published: March 2013

Abstract

Background
Infectious spleen and kidney necrosis virus (ISKNV) belongs to the genus Megalocytivirus from the family Iridoviridae. Megalocytivirus causes severe economic losses to tropical freshwater and marine culture industry in Asian countries and is devastating to the mandarin fish farm industry in China particularly.

Methods
We investigated the involvement of microfilaments in the early and late stages of ISKNV infection in MFF-1 cells by selectively perturbing their architecture using well-characterized inhibitors of actin dynamics. The effect of disruption of actin cytoskeleton on ISKNV infection was evaluated by indirect immunofluorescence analysis or real-time quantitative PCR.

Results
The depolymerization of the actin filaments with cytochalasin D, cytochalasin B, or latrunculin A reduced ISKNV infection. Furthermore, depolymerization of filamentous actin by inhibitors did not inhibit binding of the virus but affected virus internalization in the early stages of infection. In addition, the depolymerization of actin filaments reduced total ISKNV production in the late stages of ISKNV.

Conclusions
This study demonstrated that ISKNV required an intact actin network during infection. The findings will help us to better understand how iridoviruses exploit the cytoskeleton to facilitate their infection and subsequent disease.
Activation of Src, Fyn and Yes non-receptor tyrosine kinases in keratinocytes expressing human papillomavirus (HPV) type 16 E7 oncoprotein
Authors: Szalmás Anita , Gyöngyösi Eszter , Ferenczi Annamária , László Brigitta , Karosi Tamás , Csomor Péter , Gergely Lajos , Veress György , Kónya József 
Published: March 2013

AbstractBackgroundThe Src family tyrosine kinases (SFK) are cellular regulatory proteins that influence cell adhesion, proliferation, invasion and survival during tumor development. Elevated activity of Src was associated with increased cell proliferation and invasivity in human papillomavirus (HPV)-associated malignancies; therefore, transduced human foreskin keratinocytes (HFK) were used to investigate whether SFK activation is a downstream effect of papillomaviral oncoproteins. Activation of ubiquitously expressed SFKs, namely Src, Yes and Fyn, was investigated in both proliferating and differentiating keratinocytes.ResultsIn proliferating keratinocytes, Src, Yes and Fyn mRNA levels were not affected by HPV 16 E6 or E7 oncoproteins, while at the protein level as detected by western blot, the presence of both E6 and E7 resulted in substantial increase in Src and Yes expression, but did not alter the high constitutive level of Fyn. Phospo-kinase array revealed that all ubiquitously expressed SFKs are activated by phosphorylation in the presence of HPV 16 E7 oncoprotein. Keratinocyte differentiation led to increased Yes mRNA and protein levels in all transduced cell lines, while it did not influence the Src transcription but resulted in elevated Src protein level in HPV16 E7 expressing lines.ConclusionsThis study revealed that HPV 16 oncoproteins upregulate Src family kinases Src and Yes via posttranscriptional mechanisms. A further effect of HPV 16 E7 oncoprotein is to enhance the activating phosphorylation of SFKs expressed in keratinocytes.
Two cases of a rare association: double aortic arch with tetralogy of Fallot
Authors: Li Zhi-qiang , Liu Ai-jun , Li Gang , Liu Yang , Zhu Yao-bin , Liu Ying-long 
Published: March 2013

Abstract
Two cases of asymptomatic double aortic arch with tetralogy of Fallot are reported. One presented with a non-dominant left arch and left-sided descending thoracic aorta and the other with a non-dominant left arch, a right-sided descending thoracic aorta and a patent ductus arteriosus. One-stage operation was performed and both patients were discharged free of symptoms and signs related to the double aortic arch and tetralogy of Fallot after the operation. A preoperative recognition of DAA is important, especially in echocardiographic investigation.
Role of maspin in cancer
Authors: Berardi Rossana , Morgese Francesca , Onofri Azzurra , Mazzanti Paola , Pistelli Mirco , Ballatore Zelmira , Savini Agnese , De Lisa Mariagrazia , Caramanti Miriam , Rinaldi Silvia , Pagliaretta Silvia , Santoni Matteo , Pierantoni Chiara , Cascinu Stefano 
Published: March 2013

AbstractMaspin (mammary serine protease inhibitor), is a member of the serine protease inhibitor/non‐inhibitor superfamily. Its expression is down‐regulated in breast, prostate, gastric and melanoma cancers but over‐expressed in pancreatic, gallbladder, colorectal, and thyroid cancers suggesting that maspin may play different activities in different cell types. However, maspin expression seems to be correlated with better prognosis in prostate, bladder, lung, gastric, colorectal, head and neck, thyroid and melanoma cancer. In breast and ovarian cancer maspin significance is associated with its subcellular localization: nucleus maspin expression correlates with a good prognosis, whilst in pancreatic cancer it predicts a poor prognosis. Since tumor metastasis requires the detachment and invasion of tumor cells through the basement membrane and stroma, a selectively increased adhesion by the presence of maspin may contribute to the inhibition of tumor metastasis. Furthermore the different position of maspin inside the cell or its epigenetic modifications may explain the different behavior of the expression of maspin between tumors. The expression of maspin might be useful as a prognostic and possibly predictive factor for patients with particular types of cancer and data can guide physicians in selecting therapy. Its expression in circulating tumor cells especially in breast cancer, could be also useful in clinical practice along with other factors, such as age, comorbidities, blood examinations in order to select the best therapy to be carried out. Focusing on the malignancies in which maspin showed a positive prognostic value, therapeutic approaches studied so far aimed to re‐activate a dormant tumor suppressor gene by designed transcription factors, to hit the system that inhibits the expression of maspin, to identify natural substances that can determine the activation and the expression of maspin or possible “molecules binds” to introduce maspin in cancer cell and gene therapy capable of up‐regulating the maspin in an attempt to reduce primarily the risk of metastasis.Further studies in these directions are necessary to better define the therapeutic implication of maspin.
Study of the pharmacokinetic changes of Tramadol in diabetic rats
Authors: Lavasani Hoda , Sheikholeslami Behjat , Ardakani Yalda H , Abdollahi Mohammad , Hakemi Lida , Rouini Mohammad-Reza 
Published: March 2013

Abstract

Background
Besides the pathological states, diabetes mellitus may also alter the hepatic biotransformation of pharmaceutical agents. It is advantageous to understand the effect of diabetes on the pharmacokinetic of drugs. The objective of this study was to define the pharmacokinetic changes of tramadol and its main metabolites after in vivo intraperitoneal administration and ex vivo perfused liver study in diabetic rat model.
Tramadol (10 mg/kg) was administered to rats (diabetic and control groups of six) intraperitoneally and blood samples were collected at different time points up to 300 min. In a parallel study, isolated liver perfusion was done (in diabetic and control rats) by Krebs-Henseleit buffer (containing 500 ng/ml tramadol). Perfusate samples were collected at 10 min intervals up to 180 min. Concentration of tramadol and its metabolites were determined by HPLC.

Results
Tramadol reached higher concentrations after i.p. injection in diabetics (Cmax of 1607.5 ± 335.9 ng/ml) compared with control group (Cmax of 561.6 ± 111.4). M1 plasma concentrations were also higher in diabetic rats compared with control group. M2 showed also higher concentrations in diabetic rats. Comparing the concentration levels of M1 in diabetic and control perfused livers, showed that in contrast to intact animals, the metabolic ratios of M1 and M5 (M/T) were significantly higher in diabetic perfused liver compared to those of control group.

Conclusions
The pharmacokinetic of tramadol and its three metabolites are influenced by diabetes. As far as M1 is produced by Cyp2D6, its higher concentration in diabetic rats could be a result of induction in Cyp2D6 activity, while higher concentrations of tramadol can be explained by lower volume of distribution.
Uni-axial Cracking of ITO to Form Row and Column Electrodes for Roll to Roll Production of Flexible Displays and Electronics
Authors: West John Lawton , Cakmak Miko , Huang Tsang-Min , Lee Da-Wei 
Published: March 2013

ABSTRACTUniformly uni-axially aligned electrodes are formed by uniaxially cracking an indium tin oxide, ITO, film vacuum deposited on a polyester substrate. The cracks are produced by bending the film around a small radius of curvature, producing narrow, parallel cracks in the ITO separated by 5-10 μm. The cracks are enhanced by etching or uniaxial stretching. Heating and stretching is the most effective, producing a crack width of about 0.05 μm and a differential conductivity (measured parallel and perpendicular to the cracks) several orders of magnitude or greater. A passive matrix bistable cholesteric display is fabricated using top and bottom substrates with perpendicularly aligned electrodes. The addressed lines on each substrate are defined by the contact electrode, which contacts multiple cracked ITO lines. Because of the small dimension of the cracks (much less than the thickness of the active layer) they are not visible in the display. The separation between the contact electrodes must be great than 20 μm in order to include at least one crack and electrically isolate each individual line. The resulting display demonstrates how controlled cracking of ITO can replace photolithographic etching of ITO or printing of conducting polymers to produce the line electrodes required for flexible, passive matrix displays and related electronic applications. Un-axially cracking can be easily integrated into a roll-to-roll manufacturing process.
Thermodynamically Consistent Transport Coefficients for Upscaling of Compositional Processes
Authors: Salehi A. , Voskovand D. V. , Tchelepi H. A. 
Published: March 2013

Abstract
Compositional simulation of oil reservoirs is necessary for accurate representation of the physics associated with near-miscible gas injection processes. Performing the simulations using the fine-scale geocellular model is computationally expensive; as a result, reliable upscaling methods for compositional flow are needed. Compared with black-oil models, the interactions between the thermodynamic phase behavior and the sub-grid heterogeneities that are associated with compositional displacements pose significant additional challenges to upscaling.
We introduce a new framework to upscale multi-component, multi-phase compositional displacements with special attention to accurate representation of the fine-scale phase behavior on the coarse grid. We use a mass-conservative formulation and introduce an upscaled molar mobility for each phase. These upscaled flow functions account for the sub-scale absolute and relative permeability variations, as well as, compressibility effects. They also correct -somewhat- for numerical dispersion effects at the coarse-grid level. The upscaling of the thermodynamic phase behavior is performed as follows. We assume that instantaneous thermodynamical equilibrium is valid at the fine-scale, and we derive coarse-scale equations, in which the thermodynamic phase behavior is not necessarily at equilibrium.
Deviation from local equilibrium may be due to different bypassing mechanisms, such as fingering and channelling. As a result, the fugacity of a component in the two phases may not be equal at the coarse scale, and this deviation is quantified by the coarse-scale thermodynamic functions. We demonstrate that these upscaled functions can be interpreted as a transformation of the equilibrium phase space on the fine scale to a modified region of similar shape, but with tilted tie-lines. We then describe how to convert non-equilibrium coarse-scale behavior into the widely used transport coefficients (alpha-factors). The proposed methodology is applied to various challenging gas injection problems. We compare our upscaling method with standard upcaling techniques for compositional simulation, and we show improvements, both in terms of accuracy and computational efficiency, of the new approach.
Numerical Modeling of a Low-Permeability, Highly Compactible Waterflooded Reservoir
Authors: Akhimiona Nosa , Corbett Patrick W. , Geiger Sebastian 
Published: March 2013

Abstract
Performance prediction for diatomite reservoirs is very challenging because these reservoirs have a low permeability, contain fractures, and are very compactible. Therefore it has been suggested that reservoir simulation is not suitable for forecasting future hydrocarbon production or identifying production drivers because it is very difficult to obtain a good history match, particularly during waterflooding.
In this study we describe how it is possible to effectively model a low permeability, highly compactible waterflooded diatomite reservoir. The impact of pressure dependent permeability on production and cumulative oil recovery in diatomaceous reservoirs was also analyzed. The pressure dependent permeability term accounts for the effect of rock mechanical properties on recovery. This important aspect has been neglected so far and we believe it to be one of the reasons causing the difficulties in matching production history.
As a key result of our work we present a new numerical simulation model to effectively predict waterflood performance and guide reservoir management in a diatomaceous reservoir. Incorporating an adequate understanding of the geology in the numerical model proved important to be able to predict performance from wells. We hence used the geopseudo approach, a multi-phase flow upscaling methodology, which accurately models small-scale flow and structure interaction at the lamina level. Hydraulic fractures, dual porosity and dual porosity features were also incorporated in the model. The model was validated by history matching and compared to field performance. Predictions have been confirmed by the ongoing waterflood response.
Comparison of Vertex- and Cell-Centered Methods for Flow and Transport Simulation in 3D
Authors: Hægland H. , Kaufmann R. , Aavatsmark I. 
Published: March 2013

Abstract
The multipoint-flux approximation (MPFA) methods have been popular for reservoir simulation, since they handle permeability anisotropy and heterogeneity on irregular grids, they are locally mass conservative and have an explicit expression for the flux. However, they are in general not coercive, and hence, only conditionally convergent. Further, the matrix is in general nonsymmetric, and the cell stencil may become somewhat wide in some cases, increasing the run time of the linear solvers.
The control-volume finite element (CVFEM) method was introduced for reservoir simulation in the beginning of the 1990ies as a locally mass conservative alternative to the Galerkin finite element (FEM) method. Recently a vertex-centered finite element (VAG) method that can be applied on general grids and that has an explicit flux have been developed [R. Eymard et al., ESAIM: Mathematical Modelling and Numerical Analysis, 46(2), 2012]. The method is symmetric and coercive, and produces a small cell stencil.
We show that the VAG, CVFEM, and FEM are, in fact, identical for single phase flow on tetrahedral grids. Next, the VAG, CVFEM and MPFA methods are compared for hexahedral grids. We observe, that the VAG and CVFEM methods produce similar results; further, it is found that the VAG and CVFEM scheme converge for a wider range of problems than the MPFA methods, however when the MPFA-methods converge, the convergence rate in flux is better than for the other methods.
At last, the VAG flux expression is applied for tracer flow and simple two-phase flow simulations. We investigate the limit case when the volume of the vertex control volumes goes to zero.
Speeding Up Compositional Reservoir Simulation through an Efficient Implementation of Phase Equilibrium Calculation
Authors: Belkadi Abdelkrim , Yan Wei , Moggia Elsa , Michelsen Michael L. , Stenby Erling H. , Aavatsmark Ivar , Vignati Emanuele 
Published: March 2013

Abstract
Compositional reservoir simulations are widely used to simulate reservoir processes with strong compositional effects, such as gas injection. The equations of state (EoS) based phase equilibrium calculation is a time consuming part in this type of simulations. The phase equilibrium problem can be either decoupled from or coupled with the transport problem. In the former case, flash calculation is required, which consists of stability analysis and subsequent phase split calculation; in the latter case, no explicit phase split calculation is required but efficient stability analysis and optimized coding of the basic thermodynamic subroutines are still crucial to the overall speed. This work tries to provide a comprehensive strategy to increase the speed for compositional simulation. This strategy begins with the coding of the basic thermodynamic properties, including the derivatives of fugacities with respect to molar numbers. Then, in the algorithms for stability analysis and phase split calculation, successive substitution with acceleration and minimization-based second-order methods are combined to gain both robustness and efficiency. For compositional simulations, the results from previous simulation steps provide the possibility to skip stability analysis by the shadow region method in the single phase regions. The approach was implemented in the general purpose research simulator (GPRS) developed by Stanford University. GPRS is a modular, state of the art reservoir simulation and its architecture makes the implementation and evaluation of new ideas and concepts easy. Tests on several 2-D and 3-D gas injection examples indicate that with an efficient implementation of the thermodynamic package and the conventional stability analysis algorithm, the speed can be increased by several folds. Application of the shadow region method to skip stability analysis can further cut the phase equilibrium calculation time.