bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of Heavy Oil Emulsion Stability: the Effect of Various Physicochemical Parameters
Authors: Chang Hongli , Saravanan Naresh , Cheng Yaoze , Zhang Yin , Dandekar Abhijit , Patil Shirish
Published: April 2021

The formation of stable heavy oil emulsion, which may upset separation facilities and eventually lead to production impairment, is one of the most common issues encountered in the development of heavy oil reservoirs. This paper investigates the influence of various physicochemical parameters, including water cut, polymer status (sheared/unsheared), polymer concentration, demulsifier type and concentration, and the coexistence of polymer and demulsifiers on the stability of heavy oil emulsion. The viscosity of heavy oil emulsion is also studied at various water cut and polymer concentration. In this study, water-in-heavy oil emulsion was prepared at the water cut of 30% as the blank sample using heavy oil with API gravity of 14.5° and the synthetic brine. The effect of the water cut was investigated by both the bottle test method and multiple light scattering (MLS) method to validate the effectiveness and reliability of the MLS method. The other parameters were studied only through the MLS method. The results showed that the increasing water cut resulted in the decrease of heavy oil emulsion stability and could potentially invert the stable w/o emulsion to loose o/w emulsion at the phase inversion point where the emulsion viscosity peak occurred. Adding polymer, regardless of the polymer status, tended to reduce the stability of heavy oil emulsion, and the unsheared polymer contributed to less emulsion stability. However, the influence of polymer concentration was rather complicated. The emulsion stability decreased as polymer concentration increased, and further increasing polymer concentration enhanced the emulsion stability. A similar trend was also evidenced by emulsion viscosity with increasing polymer concentration. The addition of three oil-soluble emulsion breakers was able to break the heavy oil emulsion efficiently, whereas the water-soluble demulsifier had little demulsification effect. Furthermore, there existed an optimal concentration for the selected oil-soluble demulsifier to achieve the maximum separation. Although polymer itself could intensify the destabilization of heavy oil emulsion, it hindered the destabilization process of the heavy oil emulsion when the oil-soluble demulsifiers were added. This study will provide a comprehensive understanding of the factors affecting heavy oil emulsion stability.
Improved Fluids Characterization Model During Gas Huff-n-Puff EOR Processes in Unconventional Reservoirs
Authors: Yang Gang , Li Xiaoli
Published: April 2021

Despite the great potential of unconventional hydrocarbons, the primary recovery factor from such reservoirs remain low. The gas-injection enhanced oil recovery (EOR) has been proved to be a promising approach by both laboratory and simulation studies. However, the fluid model for characterizing gas and oil in nanoscale pores has not been well understood and developed. Erroneous results can be generated if the bulk fluids model is applied, resulting in a large uncertainty for the numerical simulations. The objective of this work is to propose an improved fluids characterization model tailored for the compositional simulation of gas huff-n-puff in unconventional reservoirs. The Peng-Robinson equation of state (PR EOS) is used as the basic thermodynamic model in this work. Both the attraction parameter and the co-volume parameter in the PR EOS are simultaneously modified for the first time to reflect the effect of molecule-wall interaction and geometric constraints. The collected experimental data are used for validating the model. The newly generated PVT data are imported into the compositional model to numerically simulate the gas huff-n-puff process in the Middle Bakken formation to investigate the influence of modified fluid property on the production and ultimate recovery. The improved fluids characterization model is validated applicable to calculate the confined properties of reservoir fluids. It is demonstrated that the phase envelope of the confined reservoir fluids tends to shrink. At reservoir temperature, the bubble-point pressure of the Middle Bakken oil is reduced by 17.32% with consideration of the confinement effect. Such a significant suppression represents a late occurrence of the gas evaporation, which implies a potentially higher production of the shale oil reservoir. Compositional simulation predicts that the enhanced oil recovery efficiency of CO2 huff-n-puff is unsatisfactory for the specific well in this work, which is also demonstrated in the field pilot test. However, the confinement effect results in a 1.14% elevation of the oil recovery factor in 10 years production. This work not only deepens our understanding of the confinement effect on phase behavior characterization and also shed light on the computation of the thermodynamic properties of hydrocarbons in nanopores. The results also provide practical instructions for the EOR development of unconventional reservoirs.
Effects of Imbibition During Well Shut-In on Ultimate Shale Oil Recovery: A Numerical Study
Authors: Wijaya Nur , Sheng James
Published: April 2021

Shale wells are often shut-in after hydraulic fracturing is finished. Shut-in often lasts for an extended period in the perceived hope to improve the ultimate oil recovery. However, current literature does not show a strong consensus on whether shut-in will improve the ultimate oil recovery. Because of the delayed production, evaluating the benefits of shut-in in improving the ultimate oil recovery is crucial. Otherwise, shut-in would merely delay the production and harm the economic performance.

This paper uses a numerical flow-geomechanical modeling approach to investigate the effect of imbibition on shut-in potentials to improve the ultimate oil recovery. This paper proposes that imbibition is one of the strongly confounding variables that cause the mixed conclusions in the related literature. The investigation methodology involves probabilistic forecasting of three reservoir realization models validated based on the same field production data. Each of the models represents different primary recovery driving mechanism, such as imbibition-dominant and compaction-dominant recovery.

A parametric study is conducted to explore and identify the specific reservoir conditions in which shut-in tends to improve the shale oil recovery. Ten reservoir parameters which affect the imbibition strength are studied under different shut-in durations. Comparison among the three models quantitatively demonstrates that shut-in tends to improve the ultimate oil recovery only if the shale reservoir demonstrates imbibition-dominant recovery. A first-pass economic analysis also suggests that when the shale oil reservoirs demonstrate such an imbibition-dominant recovery, shut-in tends to not only improve the ultimate oil recovery, but also the NPV. A correlation among ultimate oil recovery, flowback efficiency, and NPV also shows that there is no strong relationship between flowback efficiency and ultimate oil recovery. This study is one of the first to emphasize the importance of quantifying the imbibition strength and its contribution in helping recover the shale oil for optimum flowback framework and shale well shut-in design after hydraulic fracturing.
The Behavior of Unconsolidated Rocks in California Waterfloods Under High-Pressure Gradients
Authors: Li Yuanchun , Ershaghi Iraj
Published: April 2021

Most waterfloods in California target sandstone formations that are unconsolidated in nature with high porosities and high permeabilities. These formations are also characterized by high Poisson ratios and low values of Young's Moduli. There has been a concern if, during the waterfloods of these types of formations, fracturing takes place at high-injection gradients.

The influence of various factors on leak-off is studied in detail, indicating that with an increase in rock permeability, the leak-off velocity increases. This study included a comprehensive analysis of the characteristics of such soft formations and their responses to high injection gradients. We show that if the leak-off factors are adjusted to reflect high permeability and proper geomechanical properties, the probability of fracture formation is nil at injection gradients up to 0.9 psi/ft, for unconsolidated rooks. We computed estimated fracture width, fracture height, fracture length and noted for all three calculations, it takes gradients approaching 1psi/ft to note a non-trivial estimated value for these characteristics. This study shows that for unconsolidated formations like those in California targeted for waterfloods, the probability of fracture formation under pressure gradients of 0.9 psi/ft. is nil, and high injectivities can be exercised without the fear of fracture formation.
A Stochastic Method in Investigating Basin-Wide Underlying Distribution Functions of Decline Rate Behavior for Unconventional Resources
Authors: Ashayeri Cyrus , Paul Donald L.
Published: April 2021

Basin-wide heterogeneity of production in unconventional resources creates additional risk in field development planning. In the past few years, several data-driven models have been developed to increase the accuracy in predicting the recovery from shale gas and tight oil wells. However, many of the machine learning methods with so called "black box" approach provide deterministic results. Therefore, understanding the uncertainty associated with different development scenarios would be difficult to obtain. We have investigated the underlying statistical distribution functions that govern the production rates and decline behavior of unconventional wells. Identification and quantification of these distribution functions provide a strong tool to accurately forecast the cumulative production of a large group of wells in an unconventional basin. By understanding the relationship among geologic characteristics of different sections of the asset, and the impact of varying drilling and completion parameters, capital allocation can be done in a more efficient manner. In this paper, we have identified the statistical distribution parameters of decline behavior is a Power Law model. In doing so, we have used unsupervised clustering techniques to find an optimal number of clusters that enable observing well behaved and identifiable underlying distribution functions. Furthermore, we quantified different types of distribution functions in a trial and error workflow to provide a tool for accurately evaluating the impact of varying geologic parameters on the decline behavior of these wells. Our results show that the leading term (or leading coefficient), which also highly correlates with long term cumulative recovery, demonstrates Gamma distribution, while the power degree (or power coefficient) demonstrate Normal distribution. Peak production rate (maximum average daily rate), terminal rate (rate after switch point), and the time of terminal rate occurrence, all demonstrate Log Normal distribution.
A Practical Study of the Influence of Drill Solids on the Corrosion of Downhole Tubulars When Using Brine Based Drilling Fluids
Authors: Heath Garett , Okesanya Temi , Levey Simon
Published: April 2021

The proliferation of highly concentrated brine drilling fluids systems due to their enhanced performance benefits has instigated a plethora of technical studies on the mechanisms and control of their induced corrosion on downhole drilling tools and tubulars. The majority of these studies often overlook the effect of drill solids on corrosion rates. Therefore, a pragmatic and experimental study was conducted to investigate the effects of various factors on the corrosion rates of downhole tubulars with a streamlined focus on the obscure role of the understudied drill solids; which have not been fully elucidated.

Drill pipe corrosion coupons and drilling fluids/solids obtained from 5 similar wells (located in Grande Prairie, Alberta, Canada) were utilized for experimental analysis. Wells 1 to 4 were on the same pad (surface drilling location) drilling the same formation with the same fluid properties, while the 5th well was on a different pad but drilled the same formation with the same fluid properties to exclude disparity. Industry-standard measurement was carried out on the live used corrosion coupon rings, drilling fluids and solids obtained from these wells to determine selected properties. The total solids content analysis was carried out using an OFITE API (American Petroleum Institute) filter press. Weight loss tests on drill pipe corrosion coupons were used to determine field corrosion rates which were bolstered with the Parr Hastelloy autoclave test in the Laboratory. The oxygen content was monitored using Hach 2100Q dissolved oxygen meter.

Field data, images and experimental results showed that a rapid and minuscule increase of drill solids (as little as 1% v/v) in the active system can impact corrosion rates greater than chemical additives and even oxygen content. It was discovered that low concentration of solids can produce significant damage and a high corrosion potential in non-viscosified fluids thereby making live monitoring of drilling fluids’ properties a priority to mitigate corrosion. This study fills an important technical gap in corrosion study that is indispensable for the optimization of corrosion control in drilling operations. By carrying out a controlled and investigative study backed up with drilling field data and images, the effects of the less understood drill solids have been partially demystified.
Unique Fall Off Signatures for Stage Fracture Characterization, Actual Field Cases
Authors: Ibrahim Ahmed Farid , Ibrahim Mazher , Sinkey Matt , Johnston Thomas , Johnson Wes
Published: April 2021

Multistage hydraulic fracturing is the common stimulation technique for shale formations. The treatment design, formation in-situ stress, and reservoir heterogeneity govern the fracture network propagation. Different techniques have been used to evaluate the fracture geometry and the completion efficiency including Chemical Tracers, Microseismic, Fiber Optics, and Production Logs. Most of these methods are post-fracture as well as time and cost intensive processes.

The current study presents the use of fall-off data during and after stage fracturing to characterize producing surface area, permeability, and fracture conductivity. Shut-in data (15-30 minutes) was collected after each stage was completed. The fall-off data was processed first to remove the noise and water hammer effects. Log-Log derivative diagnostic plots were used to define the flow regime and the data were then matched with an analytical model to calculate producing surface area, permeability, and fracture conductivity.

Diagnostic plots showed a unique signature of flow regimes. A long period of a spherical flow regime with negative half-slope was observed as an indication for limited entry flow either vertically or horizontally. A positive half-slope derivative represents a linear flow regime in an infinitely conductive tensile fracture. The quarter-slope derivative was observed in a bilinear flow regime that represents a finite conductivity fracture system. An extended radial flow regime was observed with zero slope derivative which represents a highly shear fractured network around the wellbore. For a long fall-off period, formation recharge may appear with a slope between unit and 1.5 slopes derivative, especially in over-pressured dry gas reservoirs.

Analyzing fall-off data after stages are completed provides a free and real-time investigation method to estimate the fracture geometry and a measure of completion efficiency. Knowing the stage properties allows the reservoir engineer to build a simulation model to forecast the well performance and improve the well spacing.
Flow Physics of Polymer Nanospheres and Diluted Microemulsion in Fractured Carbonate Reservoirs: An Investigation into Enhanced Oil Recovery Mechanisms
Authors: Su Hang , Zhou Fujian , Wang Qing , Yu Fuwei , Dong Rencheng , Xiong Chunming , Li JunJian , Liang Tianbo
Published: April 2021

Enhanced oil recovery (EOR) in fractured carbonate reservoirs is challenging because of the heterogeneous and oil-wet nature. In this work, a new application of using polymer nanospheres (PNSs) and diluted microemulsion (DME) is presented to plug fractures and enhance water imbibition to recover oil from the tight, naturally fractured carbonate reservoirs. DME with different electric charges is compared through contact-angle and core-imbibition tests to evaluate their performances on EOR. The cationic DME is chosen because it has the fastest wettability-alteration rate and thus the highest oil recovery rate. Migration and plugging efficiency tests are conducted to identify the screened particle sizes of PNSs for the target reservoir cores. PNSs with a particle size of 300 nm are demonstrated to have the best performance of in-depth propagation before swelling and plugging after swelling within the naturally fractured cores are used in this study. Then coreflooding experiments are conducted to evaluate the EOR performance when PNSs and DME are used together, and results indicate that the oil recovery rate is increased by 24.3 and 44.1% compared to using PNSs or DME alone. In the end, a microfluidic experiment is carried out to reveal how DME works with PNSs.
Exploring soil particle size fraction and spatial redistribution of 137Cs in sloping landscapes with different lynchet height of terracing hedgerows in the remote mountain region, southwestern China
Authors: Zhou Ping , Zhuang Wenhua , Shi Zhonglin
Published: April 2021

Soil erosion is a global environmental problem related to anthropogenic activities, as well as being influenced by natural factors. The sloping cultivated lands, which have serious soil erosion, constitute a major proportion of landscape in the remote mountain region. The traditional soil conservation strategy, referred as certain height of lynchets on the edge of the terracing hedgerows of the sloping lands, plays an effective part in soil and water conservation. A typical sloping landscape with lynchet of terracing hedgerows was chosen in this study. The results showed that fine-grained sediment was deposited in front of the lynchet of terracing hedgerows, especially particle size grouped at < 0.002mm and 0.002-0.02mm. The profiles 137Cs concentration of the lynchet from the upper to the lower sloping landscape showed first increased then decreased trends as the soil depth increased. 137Cs inventory generally increased along the whole sloping landscapes. And the results suggested that the mean 137Cs inventory and erosion rate could be represented by the average value of the middle slope position. The highest value of annual erosion modulus reached to 4917.06 tkm− 2a− 1 on the upper site of the sloping lands. While the annual erosion modulus were synchronous reduced from the upper to the lower of the slope landscape, the erosion rate had the similar trends. Meanwhile, K values of soil erodibility changed from 0.0338 thm2h (hm− 2MJ− 1mm− 1) to 0.0375 thm2h (hm− 2MJ− 1mm− 1) along the slope length. There existed the logarithmic relationship between K value and 137Cs inventory in the correspondent slope position. Therefore, it is useful to study spatial patterns of soil erosion in different slope positions with the different height of lynchet of terracing hedgerows of the whole sloping landscape. Also it is important for implementing soil conservation strategy in the remote mountain region, China.
Phosphated Avocado Seed: A Renewable Biomaterial for Preparing a Flame Retardant Biofiller
Authors: Zuluaga-Parra DAVID , Ramos-deValle L.F , Sanchez Saul , Torres-Lubián J.R. , Rodríguez-Gonzalez J.A. , Borjas-Ramos J.J. , Vázquez-Rodríguez Sofia , Uribe-Calderón J.A.
Published: April 2021

The cellulose and starch present in the avocado seed can be chemically modified to obtain biofillers with fire retarding characteristics. The resulting composites could be used as substitute of the corresponding halogenated composites. For this, the avocado seed was first washed, dehydrated and pulverized, and thereafter, chemically modified with phosphoric acid in the presence of urea. This was studied using infrared spectroscopy, nuclear magnetic resonance and X-Ray photoelectron spectroscopy, in order to determine the resulting chemical structure and confirm the presence of the proposed functional groups. In addition, scanning electron microscopy and elemental analysis were used, respectively, to establish the resulting morphological changes, as well as the elements present on the surface of the modified material. Thermogravimetric analysis was also carried out in order to establish the thermal stability of the material and predict the effect on the flame retardancy due to the mentioned chemical modification. Further tests established that the obtained modified structure and morphology of the avocado seed was highly dependent on the method used to dehydrate the pulverized avocado seed. It was also determined that chemical modification greatly increased the thermal stability of the avocado seed in air atmosphere. The flame-retardant effect of the modified avocado seed was assessed in polyethylene/ethylene-vinyl-acetate (PE/EVA) composites via cone calorimeter tests. These results showed that the modified avocado seed decreased the peak of the heat release rate (pHRR) by 50% and the total heat released (THR) by 15%. This phosphated avocado seed could be a good option as a renewable biofiller for polymer composites with enhanced flame-retardant properties.
Response of Population Canopy Color Gradation Skewed Distribution Parameters of the RGB model to Micrometeorology Environment in Begonia Fimbristipula Hance
Authors: Zhang Pei , chen zhengmeng , Wang Fuzheng , Wang Rong , Bao Tingting , Xie Xiaoping , Zhang Renzu , An Ziyue , Liu Chunwei , jiang haidong
Published: April 2021

Background: The high quality and efficient production of greenhouse vegetation depend on the micrometeorology environmental adjusting such as the system warming, illumination supplement. In order to improve the quantity, quality and efficiency of greenhouse vegetation, it is necessary to figure out the relationship between the crop growth conditions and environmental meteorological factors, which could give constructive suggestions for precise control of greenhouse environment and reducing the running cost. The parameters from the color information of plant canopy reflect the internal physiological conditions, thus, RGB model has been widely used in the color analysis of digital pictures of leaves.Results: The color scale for single leaf, single plant, and the populate canopy of Begonia Fimbristipula Hance (BFH) photographs are all have a skewed cumulative distribution histograms. The color gradation skewness-distribution (CGSD) parameters of the RGB model were increased from 4 to 20 after the skewness analysis, which greatly expanded the canopy leaf color information and could simultaneously describe the depth and distribution characteristics of canopy color. The 20 CGSD parameters were sensitive to the micrometeorology factors, especially to the radiation and temperature accumulation. The multiple regression models of mean, median, mode and kurtosis parameters to microclimate factors were established, and the spatial models of skewness parameters were optimized.Conclusions: The models constructed based on the color gradation skewness-distribution (CGSD) parameters of the RGB model, can well explain the response of canopy color to microclimate factors and can be used to monitor the variation of plant canopy color under different micrometeorology.
Assessment of Various Bias Correction Methods on Precipitation of Regional Climate Model and Future Projection
Authors: S Gunavathi , R Selvasidhu
Published: April 2021

The application of regional climate model simulations (RCMs) in climate change impact studies is challengeable due to the risk of possible biases. Some sort of correction needs to be done prior to the application of RCM simulations. This study attempts to assess the performance of a simple (linear scaling and Delta Change method) and complex correction technique (Local intensity scaling, Power transformation and Distribution mapping) on CORDEX(Coordinated Regional Climate Downscaling Experiment)simulated precipitation series for the Thanjavur district. The performance at annual resolution is evaluated using various statistical parameters such as Correlation, Root Mean Square Error and Bias against the observed precipitation data. The raw RCM estimates were improved significantly after the bias correction with all methods. However, Power transformation exhibits good agreement with the observed data at the district level than other methods because it corrects both the mean and variance. The future climate was projected from 2021 to 2100 for RCP 4.5 and RCP 8.5 scenarios. The temporal distribution of future precipitation clearly shows that most of the years will receive heavy precipitation; rather, some years will receive low and average precipitation. The spatial distribution pattern indicates that the northeast monsoon will dominate over all the ranges and places. This study has provided clear information on future precipitation to the environmentalist, urban planners, and policymakers to take appropriate mitigation measures towards agriculture and disaster management. Rainwater harvesting, recharging the aquifers, afforestation, and redirecting the excess amount of water to the river through proper channels is the plausible actions suggested overcoming excessive precipitation in the future.
Well-defined nanostructuring with programmable anodic aluminium oxide template
Authors: Xu Rui , Zeng Zhiqiang , Lei Yong
Published: April 2021

Well-defined nanostructuring over size, shape, spatial configuration, and multi-combination is a feasible concept to reach unique properties of nanostructure arrays, while satisfying such broad and stringent requirements with conventional techniques is challenging. Here, we report programmable anodic aluminium oxide templates to address this challenge by achieving well-defined pore features within templates in terms of in-plane and out-of-plane shape, size, spatial configuration, and pore combination. The structural programmability of template pores arises from broad-range anodization voltage adjusting together with uneven aluminium anodization rate designing, and further relies on a systematic blueprint guiding pore diversification. Starting from the programmable templates, we realize a series of nanostructures that inherit equal structural controllability relative to their template counterparts. Proof-of-concept applications based on such nanostructures demonstrate boosted performance. In light of the broad selectivity and high controllability, programmable templates will provide an all-in-one platform for well-defined nanostructuring.
Longitudinal Study of Boxing Therapy in Parkinson’s Disease, Including Adverse Impacts of the COVID-19 Lockdown
Authors: Horbinski Craig , Zumpf Katelyn B. , McCortney Kathleen , Eoannou Dean
Published: April 2021

Background:

Parkinson’s Disease (PD) is a highly prevalent neurodegenerative disease whose incidence is increasing with an aging population. One of the most serious manifestations of PD is gait instability, leading to falls and subsequent complications that can be debilitating, even fatal. Boxing therapy (BT) uses gait and balance exercises to improve ambulation in people with PD, though its efficacy has not yet been fully proven.
Methods:

In the current longitudinal observational study, 98 participants with idiopathic PD underwent twice-weekly BT sessions. Primary outcome was self-reported falls per month; secondary outcomes were quantitative and semi-quantitative gait and balance performance evaluations. Statistical methods included segmented generalized estimating equation with an independent correlation structure, binomial distribution, and log link.
Results:

The average number of self-reported falls per month per participant decreased by 87%, from 0.86 ± 3.58 prior to BT, to 0.11 ± 0.26 during BT. During the lockdown imposed by COVID-19, this increased to 0.26 ± 0.48 falls per month. Females and those > 65 years old reported the greatest increase in falls during the lockdown period. Post-lockdown resumption of BT resulted in another decline in falls, to 0.14 ± 0.33. Quantitative performance metrics, including standing from a seated position and standing on one leg, largely mirrored the pattern of falls pre-and post-lockdown.
Conclusions:
BT may be an effective option for many PD patients.
Factors Contributing to Inequality in Access to Urban Health Service Delivery in Low Resource Setting Country Bangladesh 
Authors: Islam Mohammad Shafiqul , Kamal Muhammad Mustofa
Published: April 2021

Background: Many poor people have limited accessibility in health services and also unable to afford quality health care for poor socio-economic conditions, income disparities, and socio-cultural barriers. This study attempts to examine the factors associated with accessibility and affordability of urban health services.Methods: This research is being carried out using mixed research approach. Primary data was collected using simple random sampling technique from 150 household’s residents in Sylhet City who have experience in receiving services from the urban public health care centers. This study uses a structured interview schedule both open ended as well as close ended questions. Moreover, descriptive statistics are used for analyzing field data. Results: This study found that 56% urban poor people have inadequate accessibility of health services as they have different types of financial difficulties including maintaining medical expenditure. The health system prevail discrepancy between mentioned services in citizen charter and availability of services as education and the existence of superstitions significantly impact on access to public health care but religion and age have a little impact in getting health services. Most of the respondents either satisfied (47%) or highly satisfied (29%) with the cordiality of senior consultants, and almost half of the respondents assumed the standard of cabin service is satisfactory (44%) as well as highly satisfactory (2%); however, wealthy and powerful people of the society always get privileges over disadvantaged people paying extra money or social network to get a cabin. Unfortunately, the professionalism of nurses and 4th class employees of public hospitals are not satisfactory. Moreover, the public health system exist a high level corruption and bureaucratic barrier that affect equal health service accessibility. Furthermore, adequate information is a more challenging factor than economic and cultural factors in access to adequate health care.Conclusion: Reform in health system management and service provision are useful for promoting accessibility in health services. Therefore, expansion of health coverage, introduction to health insurance scheme, empowerment of urban poor, and ensuring efficient and accountable health service management in public hospital must be ensured for getting adequate health services.
Inquiry into GeneXpert as a complementary MDR-TB diagnostic tool in North Korea: A follow-up study of North Korean TB drug resistance patterns
Authors: Lee Noori , Kwon Hojeong , Hwang Yoohyun , Ryoo Sungweon
Published: April 2021

Background: This study aims to investigate the usefulness of GeneXpert MTB/RIF (Xpert) in diagnosing rifampicin (RIF) resistance among the patients in the secluded sanatoria of North Korea. This article is a follow up of a report that explored the characteristics of drug resistance in North Korean Sanatoria, published in 2017. Xpert is used as a diagnostic tool to check for multidrug-resistant tuberculosis (MDR-TB) in specific areas of North Korea by the Eugene Bell Foundation (EBF). While there are other diagnostic tools are used to test for RIF resistance, there is no other feasible method to consistently test for MDR-TB in North Korea. Currently, EBF exclusively uses Xpert in tuberculosis and RIF resistance diagnosis when providing medical support for tuberculosis patients in North Korea, where there is limited international access. Methods: We performed Xpert using cultured tuberculous bacilli of North Koreans and compared the result to the corresponding phenotypic drug susceptibility tests (pDST) and rifampicin resistant-determining region sequencing (RRDR). All samples were target-sequenced at the rpoB region, where unique RIF resistance related mutations, potentially specific to North Korea, were discovered.Results: Using the RRDR sequencing as the gold standard, Xpert’s sensitivity and specificity was 94.9% and 88.0%, respectively. In addition, we discovered several rare or novel mutations among the North Korean Mycobacterium tuberculosis isolates.Conclusions: RIF detection in North Korea is possible using Xpert as an alternative to pDST, as this research has shown. This research is not only imperative to North Korea, but also in locations where there is limited access to conventional pDST.
Metagenomic Identification of a New Sarbecovirus from Horseshoe Bats in Europe
Authors: Crook Jack , Murphy Ivana , Carter Daniel , Pullan Steven , Carroll Miles , Vipond Richard , Cunningham Andrew , Bell Diana
Published: April 2021

The source of the COVID-19 pandemic is unknown, but the natural host of the progenitor sarbecovirus is thought to be Asian horseshoe (rhinolophid) bats. We identified and sequenced a novel sarbecovirus (RhGB01) from a British horseshoe bat, at the western extreme of the rhinolophid range. Our results extend both the geographic and species ranges of sarbecoviruses and suggest their presence throughout the horseshoe bat distribution. Within the receptor binding domain, but excluding the receptor binding motif, RhGB01 has a 77% (SARS-CoV-2) and 81% (SARS-CoV) amino acid homology. While apparently lacking hACE2 binding ability, and hence unlikely to be zoonotic without mutation, RhGB01 presents opportunity for SARS-CoV-2 and other sarbecovirus homologous recombination. Our findings highlight that the natural distribution of sarbecoviruses and opportunities for recombination through intermediate host co-infection are underestimated. Preventing transmission of SARS-CoV-2 to bats is critical with the current global mass vaccination campaign against this virus.
Prediction of fiber breakage and matrix cracking in polymeric composites under low-cycle fatigue regimes by fuzzy and wavelet clustering of acoustic emission signals
Authors: Esfarjani Sattar Mohammadi , Azadi Mohammad , Alizadeh Mohsen , Sayar Hassan
Published: April 2021

One of methods for detecting cracks and estimating their growth in materials such as composites is the acoustic emission technique. The detection of damages, cracks and their growth in industrial composite structures, under static and dynamic loads, has a significant importance, in order to prevent any damages and increase the reliability. Therefore, achieving required technical knowledge in this field, can be helpful in repairing and the maintenance of the part in industries. The prediction of the damage in polymeric composites under static loads has been already investigated by researchers; however, under cyclic loadings, researches about this behavior are still rare. In this study, by acoustic emission sensors and analyzing experimental data, the damage, including matrix cracking, the fiber breakage and other damages (debonding, fiber pull-out and delamination) during dynamic loading was investigated. At the first stage, standard specimens were made by the pure resin epoxy and the pure carbon fiber, subjected to monotonic tensile loading and then, the frequency of the failure was extracted. Then, composite specimens were loaded in the low-cycle fatigue regime. Mechanical test results and acoustic emission data were analyzed by fuzzy C-Means and wavelet transform methods and then compared to each other to find the percentage of failures in first, mid- and last cycles by the differentiation of failure types. Results clearly indicated that the acoustic emission approach is useful and an effective tool for identifying and detecting damages in polymeric composites.
The cross-sectional effects of ribbon arch wires on Class II malocclusion intermaxillary traction: A three-dimensional finite element analysis
Authors: Xie Qin , Li Duo
Published: April 2021

Background: The application of intermaxillary traction is often accompanied by the unexpected movement of dentition, especially anchorage teeth. The aim of this study was to comprehensively compare the influence of cross-sectional shape of ribbon arch wires with edgewise and round wires on intermaxillary traction in Class II malocclusion treatment using FEA simulation.Methods: The dentofacial structure was simulated in finite element software. A retraction force of 1.5 N was applied to different cross-sectional orthodontic arch wires: a ribbon wire (0.025×0.017-inch and 0.025×0.019-inch), a rectangular wire (0.017×0.025-inch and 0.019×0.025-inch) and a round wire (Φ 0.018-inch and Φ 0.020-inch).Results: Among the three groups, ribbon wire (0.025×0.017-inch and 0.025×0.019-inch) exhibited the lowest displacement in the X-axis (12.61 μm and 12.77 μm, respectively) and Z-axis (8.99 μm and 9.06 μm, respectively). However, the 0.025×0.017-inch ribbon wire showed the highest Y-axis displacement. In the round wire group, Φ 0.020-inch wire displayed less rotation than Φ 0.018-inch wire, where the sagittal, frontal and occlusal rotation of Φ 0.020-inch wire was almost half of that of Φ 0.018-inch wire. The movement of the first molar region was intermediate between the ribbon arch group and the round wire group. Notably, the values of the 0.025×0.017-inch arch wire displacement, which were much higher than those of any other group, peaked at 0.019 mm in the central incisor region with a spike-like shape. The deformation range of the Φ 0.018-inch wire group was the largest in this study.Conclusions: The cross-section of the arch wire influenced force delivery in Class II intermaxillary traction. With the same shape, a larger cross-sectional area would lead to less mandibular dentition movement. For the rectangular arch wire and ribbon arch wire groups, since the height and width were inverted, the vertical displacement of anchorage teeth in the ribbon wire group was significantly reduced, but the possibility of buccal tipping in mandibular anterior teeth also increased.
Enhanced WSN Routing Protocol for Internet of Things to Process Multimedia Big Data
Authors: Rajasekar Vani , Jayapaul Premalatha , Krishnamoorthi Sathya , Saracevic Muzafer , Elhoseny Mohamed , Al-Akaidi Marwan
Published: April 2021

Due to the massive use of wireless Internet of Things (IoT), the advent of multimedia-big-data (MBD) in recent decades poses numerous obstacles for successful contact with the virtual era. Mobile Adhoc Network-based IoT (MANETIoT) framework is increasingly common in this regard owing to its increased communication protocols and economic efficiency. MANET comprises arbitrary, battery-driven, roaming nodes that do not have an architecture that can handle the traffic and control the IoT network. In MANET-IoT, energy usage and traffic management for the handling of MBD information are significant issues. For rapid and precise response, it is essential to route or forward information like the locations of happenings and defected in a disaster. However, it is difficult to transfer this information to the Wireless Sensor Network in disaster areas because the current networks are a disaster that has been removed. In these situations, the transmission of opportunistic knowledge may play a vital role. Current opportunistic protocols need large messages for the restoration of the cluster that leads to more energy consumption and packet loss. To overcome these issues, this work proposes the reliable, energy-efficient opportunistic protocol known as Density Clustering Opportunistic Routing Protocol (DCOR). This method sends information opportunistically in emergencies and disasters through a density-clustering protocol. Results from simulations demonstrate that the designed protocol exceeds several well-known current routing mechanisms for network energy usage and dissemination of information.
Medications and Supplements Prescription Patterns During COVID 19 Pandemic in Yemen: A Questionnaire-Based Study
Authors: Chahin Abdullah , Dhabaan Ghulam , Buhaish Abdulrahman , Shorman Mahmoud
Published: April 2021

Introduction: the study aims to better understand the COVID-19 prescription treatments and over the counter regimens in Yemen in view of limited published data and limited availability of COVID-19 testing.Methods: A 34 question web-based survey was distributed on social media outlets targeting people in Yemen. Data aggregation, analysis, and visualization were performed using Tableau and Microsoft Excel.Results: 2341 individuals reported symptoms concerning for COVID-19 infection, with 25.4% reporting a chronic medical condition. Female patients were less likely to receive medications for treatment in all age groups examined. Azithromycin was the most prescription medication prescribed (32.8%) and vitamin C being the most supplement used (62%). Around 5.5% were on Hydroxychloroquine prophylaxis prior to their diagnosis and only 12.9% of them continued using after diagnosis.Conclusions: This study provides some important information about the commonly observed treatments and prescription patterns during the COVID-19 pandemic in Yemen during May- July of 2020. The study reflects the influence of global trends in medication prescription even in resource-limited countries.
Parameter estimation and selection efficiency under Bayesian and frequentist approaches in peach trials
Authors: Angelini Julia , Bortolotto Eugenia Belén , Faviere Gabriela S , Pairoba Claudio F , Valentini Gabriel H , Cervigni Gerardo Domingo Lucio
Published: April 2021

Identification of stable and high-yielding genotypes is a real challenge in peach breeding, since genotype-by-environment interaction (GE) masks the performance of the materials. The aim of this work was to evaluate the effectiveness of parameter estimation and genotype selection solving the LMM under frequentist and Bayesian approaches. Fruit yield of 308 peach genotypes were assessed under different seasons and replication numbers arranged in a completely randomized design. Under the frequentist framework the restricted maximum likelihood method to estimate variance component and genotypic prediction was used. Different models considering environment, genotype and GE effects according to the likelihood ratio test and Akaike information criteria were compared. In the Bayesian approach, the mean and the variance components were assumed to be random variables having a priori non-informative distributions with known parameters. According the deviance information criteria the most suitable Bayesian model was selected. The full model was the most appropriate to calculate parameters and genotypic predictions, which were very similar in both approaches. Due to imbalance data, Cullis’s method was the most appropriate to estimate heritability. It was calculated at \(0.80,\) and selecting above 5% of the genotypes, the realized gain of 14.81 kg.tree1 was attained. Genotypic frequentist and Bayesian predictions showed a positive correlation (r = 0.9991; P = 0.0001). Since the Bayesian method incorporates the credible interval for genetic parameters, genotypic Bayesian prediction would be a more useful tool than the frequentist approach and allowed the selection of 17 high-yielding and stable genotypes.
ITGA2, LAMB3, and LAMC2 May Be the Potential Therapeutic Targets in Pancreatic Ductal Adenocarcinoma: an Integrated Bioinformatics Analysis
Authors: Islam Shajedul , Kitagawa Takao , Baron Byron , Abiko Yoshihiro , Chiba Itsuo , Kuramitsu Yasuhiro
Published: April 2021

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer with an abysmal prognosis rate over the last few decades. Early diagnosis and prevention could effectively combat this malignancy. Therefore, it is crucial to discover potential biomarkers to identify asymptomatic premalignant or early malignant tumors of PDAC. Gene expression analysis is a powerful technique to identify candidate biomarkers involved in disease progression. In the present study, five independent gene expression datasets, including 321 PDAC tissues and 208 adjacent non-cancerous tissue samples, were subjected to statistical and bioinformatics analysis. A total of 20 differentially expressed genes (DEGs) were identified in PDAC tissues compared to non-cancerous tissue samples. Gene ontology and pathway enrichment analysis showed that DEGs were mainly enriched in extracellular matrix (ECM), cell adhesion, ECM-receptor interaction, and focal adhesion signaling. The protein protein interaction network was constructed, and the hub genes were evaluated. Collagen type XII alpha 1 chain (COL12A1), fibronectin 1 (FN1), integrin subunit alpha 2 (ITGA2), laminin subunit beta 3 (LAMB3), laminin subunit gamma 2 (LAMC2), thrombospondin 2 (THBS2), and versican (VCAN) were identified as hub genes. The correlation analysis revealed that identified hub genes were significantly interconnected. Wherein COL12A1, FN1, ITGA2, LAMB3, LAMC2, and THBS2 were significantly associated with PDAC pathological stages. The Kaplan-Meier survival plots revealed that ITGA2, LAMB3, and LAMC2 expression were inversely correlated with a prolonged patient survival period. Furthermore, the Human Protein Atlas database was used to validate the expression and cellular origins of hub genes encoded proteins. The protein expression of hub genes was higher in pancreatic cancer tissue than in normal pancreatic tissue samples, wherein ITGA2, LAMB3, and LAMC2 were exclusively expressed in pancreatic cancer cells. Pancreatic cancer cell-specific expression of these three proteins may play pleiotropic roles in cancer progression. Our results collectively suggest that ITGA2, LAMB3, and LAMC2 could provide deep insights into pancreatic carcinogenesis molecular mechanisms and provide attractive therapeutic targets.
Derivation and Characterisation of Endothelial Cells from Patients with Chronic Thromboembolic Pulmonary Hypertension.
Authors: Tura-Ceide Olga , Smolders Valérie F.E.D. , Aventin Núria , Morén Constanza , Guitart-Mampel Mariona , Blanco Isabel , Piccari Lucilla , Osorio Jeisson , Rodriguez Cristina , Rigol Montserrat , Solanes Núria , Malandrino Andrea , Kurakula Kondababu , Goumans Marie Jose , Quax Paul , Peinado Victor I. , Castellà Manuel , Barberà Joan Albert
Published: April 2021

Rationale: Pulmonary endarterectomy (PEA) resected material offers a unique opportunity to develop an in vitro endothelial cell model of chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to comprehensively analyze the endothelial function, molecular signature and mitochondrial profile of CTEPH-derived endothelial cells to better understand the pathophysiological mechanisms of endothelial dysfunction behind CTEPH, and to identify potential novel targets for the prevention and treatment of the disease. Methods: Isolated cells from specimens obtained at PEA (CTEPH-EC), were characterized based on morphology, phenotype and functional analyses (in vitro and in vivo tubule formation, proliferation, apoptosis, and migration). Mitochondrial content, morphology, and dynamics, as well as high-resolution respirometry and oxidative stress, were also studied. Results: CTEPH-EC displayed a hyperproliferative phenotype with an increase expression of adhesion molecules and a decreased apoptosis, eNOS activity, migration capacity and reduced angiogenic capacity in vitro and in vivo compared to healthy endothelial cells. CTEPH-EC presented altered mitochondrial dynamics, increased mitochondrial respiration and an unbalanced production of reactive oxygen species and antioxidants. Conclusions: Our study is the foremost comprehensive investigation of CTEPH-EC. Modulation of redox, mitochondrial homeostasis and adhesion molecule overexpression arise as novel targets and biomarkers in CTEPH.