bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Interference between Sequential Fractures in Multistage and Multipad Hydraulic Fracturing
Authors: Lopez Manriquez Alberto 
Published: August 2019

AbstractReservoir pressure and stress behaviors are simulated during elapsed time between sequential fractures in multistage and multipad hydraulic fracturing scenarios to analyze interference between fractures and to manage potential fracture given interactions. Commonly current implemented completion techniques such as conventional sequential fracturing (CSF) and modified zipper fracturing (MZF) are investigated. Finite element analysis is implemented to simulate time dependent post-fracture behavior of formation pore pressure distribution and stress magnitude in multistage and multipad fracturing jobs in horizontal wellbores. A coupled stress-displacement to hydraulic diffusivity modeling technique was implemented to estimate formation pore pressure distribution and to account for the effective in-situ stresses in the near fracture region. Governing equations, methodology, and boundary conditions are provided in detail to allow readers to implement of this technique.Completion techniques rely on the principle of elapsed time between consecutive fractures as a mean to minimize interference between fractures optimizing resources at the same time. Post-fracture reservoir pressure and stress time-dependent behaviors within the stress shadow area are discussed. These parameters are computed at several observation points inside the reservoir such as at the tip of the fracture, away of the fracture, and at the parent horizontal wellbore. This analysis provides unique insight of scenarios occurring during sequential fracturing jobs. Permeability of rock matrix is a controlling factor of the diffusion processes occurring post-fracture. It was found that unconventional shales exhibiting extremely low permeability values show low diffusion of hydraulic fracturing fluids from the induced fracture to the formation. For this reason, disappearance of stress shadow effects in the near induced fractures region are not being allowed during elapsed times between sequential stages executed in the named completion techniques. These findings are relevant because inadequate management of elapsed time does not favor the subsequent induced fractures to grow parallel to the previous one due to changes of direction of stresses. When interference becomes critical, the phenomenon identified as "Frac-Hits" can also be predicted; therefore, managed using this tool.
Calibration of the Water Flowback in Unconventional Reservoirs with Complex Fractures using Embedded Discrete Fracture Model EDFM
Authors: Rey Alvaro , Schembre Josephina , Wen Xian-Huan 
Published: August 2019

Abstract
Modelling fracture systems where fracture mechanics and fluid flow are consistent, constitutes an essential part for predicting the performance of shale oil and gas operations. One of the challenges in these complex systems is the reconciliation of volumes of injected water during fracturing, hydraulic fracture volume and the water flowback after the well is open to production. Achieving consistency becomes even more challenging given the interdependence of multiple sources of uncertainty.
We propose a workflow that uses multiple sources of observed operational data, such as volume of water injected and produced, static pressure, soaking time and saturation logs, to calibrate a static model representing the fracture volume and rates of water imbibed into the matrix. The soaking period is modeled using Embedded Discrete Fracture Model (EDFM) that honors the fracture geometry generated by a commercial software based on unconventional fracture model (UFM). The allocation of water imbibed into the matrix during the soaking period uses imbibition capillary pressure from 3D numerical models.
After applying the proposed methodology to calibrate stimulated shale oil reservoir in a multi well pad, we can assess the relative impact of fracture complexity compared to capillary dominated flow. Additionally, we can perform sensitivities on impact of the water retained in the fracture volume and matrix, respectively. Finally, the methodology showed that we can use the imbibition capillarity to explain and reconcile water losses during the soaking period. This information is of key importance while deciding the value of the flowback rates as input during calibration of hydraulic fracture area and quality of the stimulation procedure. Extended applications of this workflow include performance assessment of gas entrapment and evaluation of EOR operations in unconventional systems.
We propose a methodology based on the hypothesis of capillary imbibition mechanism to explain and capture the volume of injected water that does not return during hydrocarbon production. This workflow, well suited for realistic complex Hydraulic Fracture Networks (HFNs) consisting of millions of fractures planes, enables calibration of fracturing fluids and water flowback while assessing the effect of the spontaneous imbibition.
A Semi-Analytical Boundary Element Method to Modeling and Simulation of Fluid-Driven Single/Multi Fractures in Reservoirs
Authors: Paknia Farzin , Ghassemi Ahmad , PourNik Maysam 
Published: August 2019

AbstractThe major goal to propose the semi-analytical method is to model/simulate hydraulic fracturing process based on closed form solution of a Theory of Elasticity problem. The analysis results for a Single-Fracture case is going to be compared to well-known resolved problem to show the performance of the proposed method. However, for the case of Multi-Fracture, some findings and outcomes are being addressed. Unlike well-known methods such as PKN or KGD, which rely on some simplifying assumptions (such as the elliptical cross-section of the fractures) our proposed method attempts to model and simulate the process numerically in 3D form which is more realistic and versatile. Several numerical methods have been proposed by industry scholars such as BEM and FEM which comprise very complicated numerical integrations and, hence, involve computational resources dramatically. Our proposed method utilizes a closed form Elasticity Problem to reduce the volume of numerical integrations and produce satisfactory results in much less amount of time. The formulation computes displacements and displacement derivatives. After computer codes were designed and developed to implement the proposed semi-analytical Method, which is a simplified form of Boundary Element Method (BEM), the results are compared to a benchmark example previously published in research papers both numerically and graphically. The computer code is capable to analyze pressurized penny-shaped fractures and compute displacement and displacement derivative fields. By acquiring these values in generated grid nodes in the domain, Cauchy strains and stresses can be obtained. By all the stress components at grid nodes, principal stress values and directions, and therefore, maximum shear stress and direction can be computed. After that, the computer code has to be verified and validated by comparison of results and well-known resolved examples. The examples are, but not limited to, Okada problems published in 1985 and 1992. The other Problem is pressurized Penny-Shaped horizontal fracture which is called Fialko Model. The comparisons show the validity of the proposed method. The boundary element formulation in this method is an exact solution and generates exact values for displacements, displacement derivatives and stress fields and does not need numerical integration. However, since hydraulic fractures of any shape and geometry are being discretized by proposed Boundary Element, the final outputs will be approximated results. This method, which is going to be shown, is much faster than other numerical methods.
Genetic deletion of Sphk2 confers protection against Pseudomonas aeruginosa mediated differential expression of genes related to virulent infection and inflammation in mouse lung
Authors: Ebenezer David Lenin , Fu Panfeng , Krishnan Yashaswin , Maienschein-Cline Mark , Hu Hong , Jung Segun , Madduri Ravi , Arbieva Zarema , Harijith Anantha , Natarajan Viswanathan 
Published: August 2019

Abstract
BACKGROUND
Pseudomonas aeruginosa (PA) is an opportunistic Gram-negative bacteria that causes serious life threatening and nosocomial infections including pneumonia. PA has the ability to alter host genome to facilitate its invasion thus increasing the virulence of the organism. Sphingosine-1 phosphate (S1P), a bioactive lipid is known to play a key role in facilitating infection. Sphingosine kinases (SPHK)1&2 phosphorylate sphingosine to generate S1P in mammalian cells. We reported earlier that Sphk2-/- mice offered significant protection against lung inflammation, compared to wild type (WT) animals. Therefore, we profiled the differential expression of genes between the protected group of Sphk2-/- and the wild type controls to better understand the underlying protective mechanisms Sphk2 deletion in lung inflammatory injury. Whole transcriptome shotgun sequencing (RNA seq) was performed on mouse lung tissue using NextSeq 500 sequencing system.
RESULTS: Two-way ANOVA analysis was performed and differentially expressed genes following PA infection were identified using whole transcriptome of Sphk2-/- mice and their wild WT counterparts. Pathway (PW) enrichment analyses of the RNA seq data identified several signaling pathways that are likely to play a crucial role in pneumonia caused by PA such as those involved in: 1. Immune response to PA infection and NF-κB signal transduction; 2. PKC signal transduction; 3. Impact on epigenetic regulation; 4. Epithelial sodium channel pathway; 5. Mucin expression; and 6. Bacterial infection related pathways.
Our data clearly suggests a role for SPHK2 in PA-induced pneumonia through elevated expression of inflammatory genes in lung tissue. Further, validation by RT-PCR on 10 differentially expressed genes showed 100% concordance in terms of vectoral changes, and 70% of genes showed concordance for significant fold change.
CONCLUSION: Using Sphk2-/- mice and differential gene expression analysis, we have shown here that S1P/SPHK2 signaling plays a key role in promoting PA pneumonia. The identified genes promote inflammation, and suppress others that naturally inhibit inflammation and host defense. We therefore propose a key role for SPHK2/S1P signaling in PA-induced lung inflammation, and could serve as a potential therapeutic target to combat PA-induced pneumonia.
Initial assessment of femoral proximal fracture and acute hip arthritis using pocket-sized ultrasound: A prospective observational study in a primary care setting in Japan
Authors: Akimoto Takashi , Kobayashi Tadashi , Maita Hiroki , Osawa Hiroshi , Kato Hiroyuki 
Published: August 2019

Abstract
Background

Acute hip pain caused by femoral proximal fractures or acute hip arthritis requires imaging for accurate diagnosis. Although pocket-sized ultrasound (PsUS) offers several advantages over other imaging modalities, there is limited information regarding its use in diagnosing femoral proximal fractures or acute hip arthritis. Thus, we aimed to validate the diagnostic accuracy of PsUS for both disorders.

Methods

In this prospective observational study, outpatients with acute hip pain were diagnosed according to a fixed procedure of the PsUS probe handling. We verified the diagnostic accuracy of PsUS findings (cortical discontinuity and joint fluid retention) and compared it with that of radiography, computed tomography, and magnetic resonance imaging.

Results

Our study included 52 outpatients (mean age, 78.0 years; female, 88.5%). Of 26 patients diagnosed with femoral proximal fractures, 14 had femoral neck fractures and 12 had femoral trochanteric fractures. Six patients had arthritis. The sensitivity and specificity for identifying cortical discontinuity in femoral proximal fractures were 0.96 and 0.92, respectively, and those for identifying joint fluid retention in acute hip arthritis were 1.00 and 0.65, respectively. The sensitivity for identifying either cortical discontinuity or joint fluid retention in femoral proximal fractures or acute hip arthritis was 0.97.

Conclusions

Negative PsUS findings of cortical discontinuity and joint fluid retention in the hip are useful for ruling out femoral proximal fractures and acute hip arthritis. PsUS and radiography have comparable diagnostic accuracies, and PsUS could aid in the initial assessment of acute hip pain among the elderly in primary care settings.
Efficacy and safety of PDE5 inhibitors in the treatment of diabetes mellitus erectile dysfunction: a systematic review and meta-analysis
Authors: Li Xiao , Zhao Qi , Wang Jingshang , Wang Jisheng , Dai Hengheng , Li Yanfeng , Chen Fei , Wang Bin , Li Haisong 
Published: August 2019

Abstract
ABSTRACT
Background: To systematically evaluate the efficacy and safety of the PDE5 inhibitors in patients with diabetes mellitus erectile dysfunction (DMED).
Methods:Random control trials (RCTs) in PubMed, EMBASE, Cochrane library, ClinicalTrials, China Knowledge Network (CNKI), Weipu Chinese Science and Technology Journal Full-text Database (VIP), Wanfang Data Resource System (WANFANG) were searched. Two researchers independently screened the literature, extracted the data and checked the results, and used the risk assessment tool to conduct a methodological quality assessment, and finally conducted a meta-analysis. The primary outcome, the erectile function scores of the International Index of Erectile Dysfunction (IIEF-EF), was recorded, while secondary outcomes (IIEF-Q3, IIEF-Q4, SEP 2 and 3, GAQ) and safety outcomes also needed attention.
Results: Twelve studies included 3,124 patients and six PDE5 inhibitors were included. Compared with placebo, PDE5 inhibitors significantly improved male erectile function in IIEF-EF (WMD = 5.73; 95% CI: 3.62 to 7.84), IIEF-Q3 (WMD = 1.14; 95% CI: 0.87 to 1.40), IIEF-Q4 (WMD=1.28; 95% CI: 1.04 to 1.51), SEP2 (WMD=21.24; 95% CI: 15.50 to 26.98), SEP3 (WMD=25.77; 95% CI: 18.78 to 32.77), GAQ (RR) =2.98; 95% CI: 2.06 to 4.32), and with the safety (WMD=5.73; 95% CI: 3.62 to 7.84).
Conclusions: PDE5 inhibitors can significantly improve the patient's erectile function, but cannot ignore their side effects.
Landscape and evolution of cis- and trans-regulation in chicken genome between two contrasted breeds analyzed in three tissues at one day of age
Authors: Wang Qiong , Jia Yaxiong , Wang Yuan , Jiang Zhihua , Zhou Xiang , Zhang Zebin , Nie Changsheng , Li Junying , Yang Ning , Qu Lujiang 
Published: August 2019

Abstract
Background

Gene expression variation is an important mechanism underlying phenotypic variation, and can occur via cis- and trans-regulation. In order to understand the role of cis- and trans-regulatory variation on population divergence of chicken, we developed reciprocal crosses of two chicken breeds, White Leghorn and Cornish Game, with major differences in size and reproductive traits, and used them to identify the degree of cis versus trans variation in brain, liver and muscle of both male and female samples at 1-day age.

Results

We provided a landscape about how the transcriptomes are regulated between two contrasted breeds by allele specific expression analysis. Our results showed that compared with the cis-regulated genes, trans-acted genes existed more extensively in the chicken genome. Furthermore, a widespread compensatory tendency exists in chicken genome. Most importantly, we found the evidence of stronger purifying selection for trans-regulatory variation than the cis-elements.

Conclusions

Our research performed the first study to describe the transcriptome regulation between White Leghorn and Cornish Game breeds and suggests that artificial selection associated with domestication in chicken may have more often acted on trans-regulatory variation.
Analysis of Affecting Factors on Patient Safety Culture in Public and Private Hospitals in Iran
Authors: Khoshakhlagh Amir Hossein , Khatooni Elham , Akbarzadeh Isa , Yazdanirad Saeid , Sheidaei Ali 
Published: August 2019

Abstract
Background: Patient safety culture is one of the main components of the quality of health services and is one of the main priorities of health studies. Considering the importance of this issue, this study aimed to determine and compare the views of health care staff on the patients’ safety culture and impact of effective factors on patient safety culture in public and private hospitals in Tehran, Iran.
Methods: This cross-sectional study was carried out on a sample of 1203 health care workers employed in three public and three private hospitals in Tehran, Iran. Stratified random sampling was used in this study. Data were collected using maslach burnout inventory and patient safety culture questionnaire (HSOPSC). IBM SPSS v22 and Amos v23 were used to perform path analysis.
Results: 867 (72.57%) females and 747 (27.43%) males with a mean age of 33.88 ± 7.66 were included. The average percentage of positive responses to safety culture questionnaire in public and private hospitals was 65.5% and 58.3%, respectively. The strengths of patient safety culture in public hospitals were in three dimensions including non-punitive response to errors (80%), organizational learning—continuous improvement (79.77%), and overall perceptions of patient safety (79.77%), and in private hospitals, were three dimensions including non-punitive responses to errors (71.41%), organizational learning—continuous improvement (69.24%), and teamwork within units (62.35%). The type of hospital and work-shift hours had an effect on the burnout and patient safety questionnaire scores (P-value <0.05). The path analysis results indicate the fitness of the proposed model (RMSEA= 0.024). The results showed a negative impact of work shift (β= -0.791), occupational burnout (β= -0.554) and hospital type (β= -0.147) on the observance of patient safety culture.
Conclusion: providing feedback on errors and requirements for the frequent incident reporting, and patient information exchange seem necessary to promote the patient's safety culture. Also, considering the negative impact of the shift work and burnout on patient safety culture, by planning and managing these factors appropriately, correct actions could be designed to improve the safety culture.
Reduced flow in the left ventricular apex after anterior acute myocardial infarction: a case control study using 4D flow MRI
Authors: Corrado Philip A , Macdonald Jacob A. , Francois Christopher J. , Aggarwal Niti R. , Weinsaft Jonathan W. , Wieben Oliver 
Published: August 2019

Abstract
Purpose

Acute myocardial infarction (AMI) alters left ventricular (LV) hemodynamics, resulting in decreased global LV ejection fraction and global LV kinetic energy. We hypothesize that anterior AMI effects localized alterations in LV flow and developed a regional approach to analyze these local changes with 4D flow MRI.

Materials and Methods

4D flow cardiac magnetic resonance (CMR) data was compared between 12 anterior AMI patients (11 males; 66±12yo; prospectively acquired in 2016-2017) and 19 healthy volunteers (10 males; 40±16yo; retrospective from 2010-2011 study). The LV cavity was contoured on short axis cine steady-state free procession CMR and partitioned into three regions: base, mid-ventricle, and apex. 4D flow data was registered to the short axis segmentation. Peak systolic and diastolic through-plane flows were compared region-by-region between groups using linear models of flow with age, sex, and heart rate as covariates.

Results

Peak systolic flow was reduced in anterior AMI subjects compared to controls in the LV mid-ventricle (fitted reduction = 3.9 L/min; P=0.01) and apex (fitted reduction = 1.4 L/min; P=0.02). Peak diastolic flow was also lower in anterior AMI subjects compared to controls in the apex (fitted reduction = 2.4 L/min; P=0.01).

Conclusion

A regional method to analyze 4D LV flow data was applied in anterior AMI patients and controls. Anterior AMI patients had reduced flow, particularly in the LV apex, relative to controls.
A novel SPTB gene mutation in neonatal hereditary spherocytosis: a case report and literature review
Authors: Liu Yang , Song Li , Shu Jianbo , Fang Yulian , Sun Chao , Li Na , Liu Geli 
Published: August 2019

Abstract
Background: To enhance our understanding on the diagnosis and treatment of neonatal hereditary spherocytosis (HS).
Methods: We summarized the clinical data and gene test results of a neonatal HS caused by a new mutation of SPTB gene. Meanwhile, a comprehensive literature review was performed. Gene sequencing and analysis was carried out for the crucial splicing signals on the exons and introns of the 302 known pathogenic genes (e.g. ANK1, SPTA1, EPB42, SLC4A1 and SPTB) associated with the genetic deficiency of erythrocyte.
Results: A 26-day-old girl presented jaundice, anemia, an increased count in peripheral blood reticulocyte and spherocyte, as well as positive findings in the acidified glycerol hemolysis test. Gene sequencing revealed a new mutation of c.3737delA P. (Lys1246fs) in the exon 16 of SPTB (14q23 | NM_000347.5) gene in the patient and her father. The mutation was a frame-shifting mutation, which may result in truncation of beta-haemoglobin in erythrocyte membrane and loss of its normal function, leading to the occurrence of diseases.
Conclusion: For the neonates with jaundice and anemia, family history, erythrocyte index and peripheral blood smear findings contributed to the diagnosis of HS. Gene sequencing is helpful for the diagnosis. We identified a novel mutation of SPTB gene, which may be pathogenic through modulating the activity of β-spectrin in the erythrocyte membrane.
Systematical identifications of prognostic meaningful lung adenocarcinoma subtypes and the underlying mutational and expressional characters
Authors: Lei Ting , Lv Zhenyang 
Published: August 2019

Abstract
Lung adenocarcinoma (LUAD) is one of the most common cancer types. However, the high heterogeneity and complexity of LUAD hinder effective treatments. This study aimed to identify the key prognosis impacting genes and the corresponding subtypes for LUAD. Specifically, the cox proportional hazards model was combined with a causal regulatory network to help reveal which genes play master roles among numerous prognosis impacting genes, and sub-types were identified based on expressional profiles of the master genes. As results, a collection of 75 genes were recognized as the master prognosis impacting genes, where some were enriched in mTOR signaling and lysosome pathways. Based on their expressions, the LUAD patients were separated into two sub-types displaying remarkable differences in expressional profiles, prognostic outcomes and genomic mutations. Meanwhile, the two subtypes were re-discovered from two additional LUAD cohorts based on only the top-10 important master genes. This study provides a comprehensive description on the key prognosis-relevant genes and an alternative way to classify LUAD subtypes which can promote LUAD precision treatment.