bluuebunny/crossref_metadata_2025 huggingface dataset:
Shear Response of Rough Rock Discontinuities Subjected to Impact Loading: Experimental Study and Theoretical Modelling
Authors: Wang Feili , Wu Bangbiao , Wang Shuhong , Meng Fanzhen , Xiu Zhanguo , Wang Chonglang
Published: April 2022

The presence of discontinuities can significantly weaken rock masses, whose shear load-bearing capacity is always dictated by discontinuity failures. The shear response of rock discontinuity has been extensively studied under low loading rate conditions, while the effect of impact loading on its shear strength was unclear. To address this issue, rock discontinuity samples with quantified surface roughness were tested under six normal stresses (0%, 5%, 10%, 15%, 20%, and 25% of its uniaxial compressive strength) and different loading rates (varying from 100 MPa/ms to 700 MPa/ms) by a novel-designed impact shear testing system. Experimental results show that the impact shear strength is proportional to the loading rate and exhibits significant rate dependence. Moreover, the cohesion is clearly rate-dependent and the friction angle keeps constant during impact loading, which shows obviously different behaviors with those under static loading conditions. Considering the rate effect of the shear strength parameters, the shear strength criterion of rough rock discontinuity under impact loading was established. Furthermore, a statistical constitutive model was proposed by incorporating the Weibull distribution of the shear damage. The successful application of the theoretical model to the experimental data shows that the proposed models can well predict the shear strength and describe the shear damage of rough rock discontinuities under impact loading.
LA DISOLUCIÓN SOCIAL Y LAS SOCIEDADES “ECONÓMICAMENTE VIABLES” EN LA LEGISLACIÓN SOCIETARIA Y CONCURSAL ARGENTINA
Authors:   Universidad de Belgrano, Casella Daniel Alejandro , Jurado María Alejandra
Published: April 2022

I. Introducción. Planteo del problema. II. La ley societaria argentina. 2.1. La pérdida del capital social y la subsistencia de la sociedad. 2.2. La disolución de la sociedad y la conservación de la empresa. La viabilidad económica como presupuesto de reconducción. III. El principio de continuidad de la actividad empresarial en el derecho concursal. 3.1. Introducción. 3.2. La propuesta de acuerdo preventivo. 3.3. La imposición del acuerdo o “cramdown power”. 3.4. Salvataje o Cramdown “a la criolla”. 3.5. El art. 48 bis de la LCQ. 3.6. La Quiebra: la continuación inmediata de la empresa. 3.7. La continuidad de la empresa por cooperativa de trabajadores. IV. Conclusiones.
EL CONCEPTO DE REESTRUCTURACIÓN EN LA DIRECTIVA 2019/1023 Y SU TRASLACIÓN AL DERECHO ESPAÑOL DE SOCIEDADES DE CAPITAL
Authors:   Universidad de Sevilla, Vázquez Cueto José Carlos
Published: April 2022

En este trabajo se analiza el concepto de reestructuración que toma la Directiva (UE) 2019/1023, sobre reestructuración e insolvencia, sobre cuya base se establece el marco normativo que han de incorporar los Estados miembros. Asimismo, se examinan las operaciones societarias, incluidas dentro de este concepto, cuya aprobación es competencia de la junta general en el Derecho español, y respecto de las que el legislador español debería prever medidas para evitar que los socios pudieran obstaculizar injustificadamente su adopción o ejecución.
SPACS: UNA PERSPECTIVA PRÁCTICA
Authors:   Corporate de Latham & Watkins, Sánchez-Dafos Jose Antonio , Vega-Penichet García Celia ,   Corporate de Latham & Watkins
Published: April 2022

Con más capital disponible que nunca para llevar a cabo inversiones y con los tipos de interés más bajos de los últimos tiempos, los inversores han optado por instrumentos no convencionales que permitan alcanzar una rentabilidad superior a la que se pueda encontrar en los activos financieros más tradicionales.
Tracing of Induced Heatwaves to Determine Well Inflow Distribution
Authors: Skogen Erik , Ottesen Tore , Mo Sjur , Moen Terje , Nyhavn Fridtjof , Johansen Stein Tore , Hjelstuen Magnus Blihovde
Published: April 2022

This paper introduces a novel wireless well inflow/outflow profiling technique and illustrates how operators may gain from its use. Results from well-scale multiphase flow loop tests are presented.

A system has been realized, based on tracing of heatwaves induced in the well fluid by wireless heat sources embedded in the completion string or otherwise deployed along the reservoir section of hydrocarbon-producing wells. The heatwaves are subsequently registered as temperature anomalies as they flow past one or more downstream temperature sensor(s). The data will be available through an existing SCADA system for real time analysis and interpretation.

Heatwave travel times and the Residence Time Distributions (RTD) in different parts of the well system are derived using flow models. This forms the basis for estimating "what is flowing where and how much?".

Extensive tests were carried out at SINTEF's flow laboratory. Single- and multiphase (oil-water) fluid compositions were produced through a well-scale horizontal flow loop with multiple inflow points, and across a range of flow regimes from laminar and up to fully turbulent regimes. Based on theoretical work and the laboratory results models were developed to accurately represent the transport of heat from heat sources to temperature sensor placed downstream. For the simplest case of turbulent single-phase flow, heatwaves are well defined for the whole tubing length and flow rates at various inflow points can be accurately determined. Also, for cases of multiphase and laminar flows, valuable flow information can be extracted from the downstream sensors. Models are being developed for all these cases.

A brief comparison to alternative monitoring techniques is made. The technique described in this paper is basically a tracer technique and similarities with flow monitoring by chemical tracers can be observed. Unlike traditional tracer technologies heatwave applications are not limited to production cases. It will also be a tool for water injector wells and wells for CO2 sequestration.
CO2 Caprock Threshold Pressure Measurements for the Northern Lights Reservoir
Authors: Zuta John , Vatne Kåre Olav , Askarhinade Reza , Iversen Jan Erik , Lohne Arild , Mousa Al-Noth Mohammed , Mehrabi Ali , Thompson Nicolas
Published: April 2022

Assessing the representative threshold capillary property of a reservoir formation is very important in the context of reservoir production, basin modeling and geological storage. The long-term safety of CO2 storage is highly dependent on the permanent sealing capacity of the cap rock.

As part of the Northern Lights CO2 storage project, Equinor with partners Shell and TotalEnergies, in Q1 2020 drilled well 31/5-7 in exploitation license EL001 southwest of Troll A in the northern part of the North Sea. The objective of the well was to investigate whether the formations in the Lower Jurassic Dunlin Group (Cook and Johansen storage formations and Drake Formation cap rock) are suitable for storage of CO2.

In this work, laboratory experiments were used to determine the CO2 cap rock threshold pressure for reservoir core material from well 31/5-7. The experiments were performed at reservoir conditions, 260.5 bar and 83.5°C. Prior to the tests, the permeability to water was measured to be in the nano Darcy range. The dynamic method for measuring the threshold capillary pressure relies on establishing a flow of water through the plug before CO2 reaches the plug's surface. Due to the low permeability of the plugs, the amount of water that must be displaced before CO2 contacts the plug's surface was kept low from the inlet. Thus, if CO2 contacts the plug's surface at a pressure below the threshold value, the water production should stop. The onset of water production from the outlet will define the threshold pressure, as CO2 will flow into the plug once the threshold pressure is exceeded. The CO2 pressure was gradually increased stepwise up to a maximum of 360.5 bar over 4 weeks.

The capillary threshold pressure for CO2 was measured for three plugs and was in the range 30 - 50 bar above the pore pressure of the reservoir at reservoir conditions. However, should the aquifer pressure exceed this value, the containment of CO2 below the Drake formation is ensured by its very low permeability (few tens of nD) that will preferentially drive the CO2 horizontally within the storage formations rather than vertically through Drake formation. No values were obtained within the time frame of the experiments for the two remaining plugs. The plugs were exposed to an injection pressure of 360 bar, 100 bar above the pore pressure, and no entry was observed. Thus, the minimum capillary pressure is expected to be greater than 100 bar for these two plugs.
Overcoming Subsurface Challenges to Develop a Thin Oil Column - A Case Study from the Five Decade Old Gekko Discovery in the Alvheim Area
Authors: Tveiterå Leif Kristian , Fismen Morten , Bang Asgeir , Chatterjee Amitabha , Osvoll Ivar Frøland
Published: April 2022

The Alvheim field has been on production since 2008 through the Alvheim FPSO. While the FPSO has produced more than twice the initial Alvheim area production estimate of 250 mmboe, the ambition is to produce a billion barrels from the area via continuous infill drilling and near-field exploration and developments. An example of the latter is the joint Kobra East and Gekko (KEG) tie-in. This paper describes the various anticipated subsurface challenges, risks and proposed solutions in developing the Gekko field, discovered in 1974 (25/4-3) and subsequently appraised in 2003 (25/4-8) and 2018 (25/4- 13S&A), revealing a thin oil column (6.5m) between a gas cap and a large aquifer.

The Gekko reservoir is of Late Paleocene age and consists of turbiditic sand deposits of the Heimdal Formation. Two subtle four-way closures (Gekko North and Gekko South) define the trap. Reservoir properties are excellent with high porosities and multi-Darcy permeabilities.

The technical challenges associated with producing a thin oil column sandwiched between the gas cap and a strong aquifer led to the field being viewed initially as a gas discovery and not included in the Alvheim development.

New appraisal wells and additional seismic data sets, advances in seismic techniques and a new area petrophysical study helped to improve the subsurface understanding. Development of the thin oil column has been evaluated using detailed reservoir simulation models to determine optimal well placement and completion solutions, resulting in a well design comprising of horizontal tri-lateral wells of approximately 4000 m reservoir lengths. New completion technologies such as autonomous inflow control devices (AICD), independent inflow control valves (ICV) installed in each lateral and downhole water cut meters are expected to play a pivotal role in unlocking the development potential.

The work done has resulted in a successful PDO submission (June 2021) for the KEG development. Four tri-lateral wells will be drilled during 2023, with first oil expected in 2024. This development represents the largest ongoing tie-in project to Alvheim, adding reserves of approximately 40 mmboe.

Producing a thin oil column such as Gekko presents significant subsurface challenges. Such a development will require targeted technologies and multi-disciplinary coordination. Successful development will reinforce the near-field development strategy for the Alvheim FPSO and add to its production volumes and production life. To be able to finally develop the field fifty years after it was discovered can also serve as a benchmark for future stranded developments of similar scope and complexity.
ECalc - A Computationally Efficient Tool for Emission Forecasting
Authors: Skjerve Kari Børset , Martinsen Frode , Solbraa Even , Espelid Øystein
Published: April 2022

eCalc is the name of a software tool for high-quality emission forecasting. eCalc allows integration of subsurface and operational knowledge and calculates emission forecasts directly relating drainage strategy to operational strategies and equipment. Emissions directly relating to reservoir drainage (CO2 in particular) vary with the reservoir production rates and pressures, and the process assumptions. Emissions from drilling, flaring and mobile vessels may be included for integrated bookkeeping. eCalc is a holistic asset prognosis tool for calculation of the total emissions allowing break-down into single emission sources.

eCalc has integrated energy functions to be used for modeling the energy usage of various process equipment such as pumps, compressors, generators, and turbines. The energy functions are models that relate input variables to energy consumption. The input variables are typically rate and pressures. For the compressor models, it uses compressor curves and thermodynamical models to calculate the shaft work needed for the predicted compression work through a single or a series of compressors. Also, it has built in models for future low-pressure projects, for less mature tie-in projects and new builds where vendor data is not available. In addition, there is also support for energy functions based on tables generated by external software (e.g. Unisim, Hysys).

The flexibility of the software allows evaluating varying subsurface drainage strategies combined with process modifications in an integrated calculation. The tabulated energy functions, or likewise thermodynamical calculations, allow for a fast and easy to use calculation tool that can be used in multi-realization systems like the fast model update environment. eCalc is batch callable in Unix and can thus be easily integrated in workflows. eCalc also allows integration with external software, like for example numerical optimizers.

eCalc uses process knowledge to mimic anti-surge and minimum flow without needing iterative solvers. Depending on where the operating point is relative to the chart, eCalc implements control strategies to automatically mimic process control. Eg if the operating point is in the surge domain, eCalc adds mass rate to the rate input to move to a point on the control line.

A forward model results which is at the core of the calculations. It is not intended to replace the commercial process simulation software but allows subsurface personnel access to simplified process calculations and therefore opens the possibility for a better cross-disciplinary working environment.

The integrated tool makes mutual information exchange between operations, subsurface and sustainability disciplines easy. The engineering approach with real physical models, capacities and data provides a high-quality emission forecast suitable for the long term. eCalc has been implemented on nearly all Norwegian installations (Espelid et al, 2022) and three generic examples are included in this paper.
Implementation of a Safe, Efficient, and Robust Whipstock System
Authors: Gregurek Philip Matthew , Eidem Morten , Nguyen Tuan Anh , Grindhaug Gaute , Ferdin Valerie , Ali Mohsen , Hern Greg , Munir Waqas
Published: April 2022

The whipstock system has successfully improved on operation efficiencies by reducing the total operational time by up to 50%. This is achieved by the system's ability to bypass the upfront cleanup / gauge run, on site assembly, and limitations on running speed. The absence of personnel in the red zone decreased the associated risk during deployment of the system. Even when met with faulty draw works, poor well conditions, and ovality in the casing the system was deployed without issues. Flawless execution of the system was demonstrated by setting the whipstock on the first attempt. The quality of the window was verified with the passing of a rotary steerable drilling assembly. No additional trips were required to ream or polish the casing exit window.

The mill to whipstock interface delivers on improved safety, robustness, and efficiency of a casing exit operation. This connection provides a positive impact in the reduction of carbon emissions by effectively decreasing the required time to perform a casing exit. The redundant set anchor prevents additional runs due to its redundant activation feature and its ability to be reset and reoriented if required.

This system delivers on improved safety, robustness, and efficiency of a casing exit operation by providing a positive impact in the reduction of carbon emissions. From multiple aspects, decreasing the required time to prepare the well and perform a casing exit.
Smart Well Foundation, the Cost Efficient and Environmental Choice for Field Developments
Authors: Mathis Wolfgang , Holen Ole Kristian , Bjørvik Trine Lise , Strand Vidar , Witting Fredrik
Published: April 2022

Conventional subsea satellite production well design requires the well to be drilled and completed with the drilling rig before flow line and umbilical are installed with other specialized vessels. This causes a time delay between well drilling/completion and production start-up, amounting to several weeks. By installing a well foundation with integrated conductor, manifold, pipeline and umbilical tie-in points, this costly time delay can be reduced, and facilitate instant or accelerated production.

The CAN® (Conductor Anchor Node) technology is the structural foundation for the well construction. Smaller marine vessels can be used for installation and recovery. Instead of drilling a 36 in. or 42 in. hole, running the conductor, and cementing operations, a vessel is used to install the well foundation ahead of rig arriving. The technology also offers unparalleled load capacities for satellite production wells, mitigating operational risk by preventing mobilization and handling of spud BHA and conductor handling equipment on the rig, preventing conductor as well as cementing failures, excellent inclination control and many more technical, cost, and environmental benefits.

In summary these advantages result in increased efficiency, shorter project execution time, faster time to first oil, reduced operational risk and lower cost ultimately lowering the CO2 footprint (21-44% reduction, or 400-600 mT of CO2) of the top-hole section of any well, development as well as exploration wells.
Field Validation of a Full Transient Hydraulics Model Leveraging Digital Twin and Real-Time Rheology Technology, Case Studies from North Sea Continental Shelf
Authors: Starostin Alexander B. , Forshaw Matthew J. , Aragall Roger , May Roland , Dahl Thomas G. , Macpherson John D.
Published: April 2022

Poor management of annular pressure regimes, or inadequate transport of drilled cuttings from bit to surface, results in significant non-productive time (NPT) and invisible lost time (ILT). On average one in three North Sea continental shelf wells requires the technical sidetrack of a section, pushing drilling projects over authorized expenditure (AFE). Insufficient control of real-time hydraulics is a significant contributing cause.

Pre-well planning applications and real-time (RT) engineering applications have used, for decades, steady state hydraulics models. In recent times, this modeling has been augmented with transient hydraulic models which have improved the capability, especially in real-time. Our advisory and control system maintains a digital twin with tools and environment, updates the digital twin state from measurements and transient wellbore flow modelling, and assists range of operations.

This paper details the features of a one-dimensional multi-phase transient model of wellbore flow capable of comprehensively resolving the temporal and spatial course of pressure, cuttings concentration in suspension, and those in static beds along the wellbore. The model considers local variations in rheology, cuttings slip, cuttings deposition, and cuttings mobilization. The cuttings concentration uses a drift-flux model, populated with coefficients from high-resolution 2D and 3D CFD simulations. The numerical solution is designed for effective real-time execution.

A comparison of simulation outputs with measurements demonstrates the accuracy of the model: equivalent circulating and static densities (ECD & ESD) and standpipe pressures are compared to their measured counterparts from surface and downhole pressure sensors; simulated outlet cuttings mass is compared to measured skip weights.

The evaluation also demonstrates that accuracy is a function of input data availability and quality: how RT rheological sensor data, providing a constant feed of Fann-75 data to the model, impacts simulation results.

Results clearly show the superiority of a real-time transient hydraulic model, obtaining a 10-20% tighter correlation with measured ECD & ESD, and a simulated mass out of the wellbore within 4% of the measured skip weights during both drilling and section clean-up operations.

Simulation results using input low-resolution bob-and-cup measured mud density and rheology have less accuracy than those supplied with a continuous feed of real-time density, rheology, and temperature from an automated measurement system. A sensitivity analysis on input variables serves to identify which fluid properties are the most essential to measure automatically.

The paper will conclude with an overview on the implementation of the physics-based models in a SCADA style drilling advisory and automation system.
Novel Workflows to Model Fishbone Wells and Generate Reliable Production Forecasts, Employing an Economic Optimization Procedure
Authors: Dousi Niek
Published: April 2022

In the last years it has become technically- and economically feasible to drill productivity enhancing fishbone wells in tight and/or thin formations or in areas where hydraulic fracturing is not permitted due to local environmental regulations. Modeling of fishbone wells is complex and currently very time-consuming. A fully integrated workflow has been developed to model fishbone wells, using dynamic models to generate reliable production forecasts. This novel workflow comprises of the implementation of pre-defined well trajectories and number of needles in a box- and/or full-field dynamic model. Subsequently, the number of needles and number of wells to be drilled is optimized using a workflow driven by project economics.

The workflow comprises the ability to generate forecasts for different well configurations, such as horizontal well length, well depth, number of needles and needle lengths. The needles are modeled explicitly as multilaterals. The needles cannot be oriented during drilling. To obtain a reliable prediction of the recovery of the fishbone wells, a so-called "needle rotation randomizer" has been developed. The orientation of the needles is important in the prediction of future production, as the ratio between the horizontal- and the vertical permeability (KvKh) can be significant in tight formations.

The attractiveness of different well- and needle configurations, as well as the number of fishbone wells is assessed as part of the workflow. This paper addresses how different scenarios, including variation of the number of needle stations (subs) and wells impact project economics by applying a simplified Net-Present-Value (NPV) calculation. Modelling results highlight that more subs will lead to a higher production rate, with corresponding higher NPV's. However, too many subs will lead to lower NPV's, as recovery increase becomes more marginal. It will be demonstrated how modelling can be used to optimize the number of subs. With further full-field dynamic modeling the production forecast can be enhanced by varying well numbers and their spacing the using the optimized number of subs. This paper will showcase how, a fully optimized full field development plan, applying fishbone wells can be generated using the applied workflow in a very short timeframe.

The novel workflow involves the generation reliable production forecasts for fishbone wells, employing a "needle rotation randomizer". Secondly, the new workflow enables optimizing the number of subs and wells, using an efficient economic optimization assessment.
A Bayesian Approach for Improved Estimation of Inflow Profiles in Oil Wells
Authors: Moen Ola Rasmus , Mo Sjur , Varagnolo Damiano
Published: April 2022

A novel concept for estimating inflow profiles in oil wells is based on introducing heatwaves at known times and locations and measure the temperature waves further downstream. The heatwaves arrival times and shapes are known to depend on the source location and inflow profile along the traveled path. Estimating the inflow profile is then done by fitting an inverse model to multiple measured waves. This study aims at introducing a 1D physics-driven model that may be used for this estimation purpose and validate & optimize it by means of experimental data.

We assume the presence of uncertainty in both the model and the data. The former arises from both simplifications needed to achieve acceptable computational time, and several assumptions on the governing processes. Uncertainty in the data stems instead from measurement noise and preprocessing steps necessary to transform non-stationary time-series data so to be suitable for fitting the model. To account for these uncertainties, we cast the problem in a Bayesian framework by applying Markov Chain Monte Carlo approaches to infer the distribution of the model parameters.

The results show that the uncertainties introduced in the model through dimensionality reduction from 3D to 1D are largely Gaussian in nature with the mode close to the original estimate. This indicates that the model matches the data to a satisfactory degree given the available experimental data quality. Overall this is an indication both towards the validity of the model, and towards the fact that a purely physics-driven approach matches measurements resulting from a wide variety of system inputs (a further evidence that the concept is valid).

The most challenging aspect of this study has been that of processing and fitting the data in a satisfactory manner. Especially the observed difference in time constants of the different sensors used in the flow loop experiments introduced challenges related to averaging/combining data from several sensors. Further exploration into methods of combining cross-sectional measurements to 1D along with parameterizations or alternative methods of fitting are perhaps the most clear-cut areas for further research. In the paper we present both novel methods for data preprocessing and illustrate how advanced probability-based methods may be used in a fruitful way for development of improved and computationally fast well inflow estimation models.
Collective and individual mathematical progress: Layering explanations in the case of Sierpiński triangle
Authors: Dreyfus Tommy , Apkarian Naneh , Rasmussen Chris , Tabach Michal
Published: April 2022

Qualitative research on classroom-based mathematics learning in inquiry-oriented classrooms is scarce. This paper presents a methodology aimed at developing a rich understanding of the interplay of mathematical progress in the different settings in which learning in such classrooms occurs - individuals, small groups, and the whole class. For this purpose, we enhance a theoretical-methodological approach of coordinating Documenting Collective Activity and the RBC-model of Abstraction in Context that has been developed in earlier studies. We do this using an intact lesson on the area and perimeter of the Sierpiński triangle in a mathematics education master’s level course on Chaos and Fractals. The enhancement of the methodology allowed integrating the Collective and Individual Mathematical Progress (CIMP) by Layering the Explanations (LE) provided by the two approaches and thus exhibiting the complexity of learning processes in inquiry-oriented classrooms.
Nature of Electrically Induced Defects in CVD-grown Monolayer MoS2
Authors: Ansh Ansh , Patbhaje Utpreksh , Kumar Jeevesh , Meersha Adil , Shrivastava Mayank
Published: April 2022

We find that defects are also introduced by prolonged operation of single crystal CVD-grown monolayer MoS2 FETs which hinder the overall performance. These defects result in threshold voltage instabilities, enhanced channel conductance, improved screening of charged impurity scattering sites and better thermal management in MoS2 transistors. It turns out that long-term electrical stress (LTES) results in a piezoelectric response in MoS2 which leads to permanent change in the material’s molecular configuration. This change in the molecular structure of MoS2 is, in fact, weakening of Mo-S bonds. Such a deviation from the original crystal structure results in suppressed hopping transport within the channel while increasing free electron concentration and hence reduction in channel potential without increasing sulfur vacancy concentration. It is also found that these defects result in enhanced thermal dissipation capability of MoS2 transistors. These results are particularly important from a fundamental perspective because they unveil a unique self-adaptive piezoelectric response in MoS2 against long-term high-field transport which eventually modifies its electrical and thermal transport properties. This is an entirely new property of single crystal CVD-grown monolayer MoS2 which has remained unidentified. It triggers a need to reconsider supply voltage requirements of MoS2-based CMOS circuits for low-power logic applications.
Biochar Modification with Hematite and Goethite for Efficient Persulfate Activation and Pollution Degradation
Authors: Sharma Hem Chandra , Chen Hao , Chandel Aneesh Kumar
Published: April 2022

Using biochar to adsorb and degrade organic contaminants has attracted increasing attention due to it is relatively low cost and high efficiency. In this work, two magnetic biochar were synthesized by pyrolyzing a mixture of naturally-occurring Hematite or Goethite mineral and pine needle biomass. The biochar composite was characterized with X-ray diffraction, scanning electron microscopy, and surface area analyzer. The result demonstrated iron minerals have been deposited on carbon surfaces and been reduced to Wustite or Goethite minerals. In comparison to the unmodified biochar, the iron mineral modified biochar had better sorption ability, likely because the iron mineral particles on the carbon surface served as additional sorption sites for Sulfamethoxazole (SMX) removal. After modification, the biochar also showed higher persulfate activation capacity with radical generation: at 4 hours, neutral pH, 67.5 and 77.9% of persulfate is activated with hematite and goethite modified biochar, where only 11.7% persulfate is activated by unmodified biochar. With persulfate, Goethite modified biochar showed better SMX removal capacity than Hematite modified biochar with about 79% of SMX removed in 4 hours. Solution chemistry such as pH and co-exist humic acid can affect SMX removal by affecting iron minerals. Because the magnetized biochar can be easily isolated and removed with external magnets, it can be used in various contaminant removal applications.
Paraquat is an agonist of STIM1 and Increases Intracellular Calcium Levels
Authors: Yang Wenyu , Tian Rui , Zhu Yong , Huang Peijie , Ma Xinrun , Meng Xiaoxiao , Dai Wentao , Tao Yiming , Chen Daonan , Zhang Jiaxiang , Lu Jian , Xie Hui , Jian Xiangdong , Yang Zhengfeng , Wang Ruilan
Published: April 2022

Paraquat (PQ) is an efficient herbicide utilized worldwide but leads to pulmonary fibrosis and high mortality with no antidote in mammals. PQ is well recognized to produce amounts of ROS, leading to epithelial-mesenchymal transition (EMT) in type II alveolar (AT II) cells, followed with pulmonary fibrosis. Intriguingly, strategies developed to target oxidative stress exhibit limited therapeutic effects, indicating that other molecular targets exist for PQ toxicity. Herein we reported that PQ is also an agonist for STIM1 that increases intracellular calcium levels. Particularly, PQ promotes STIM1 puncta formation and association with TRPC1 or ORAI1 for store-operated calcium entry (SOCE), which increases intracellular calcium levels and NFAT activation. Further studies revealed the importance of P584&Y586 residues in STIM1 for PQ association that facilitates STIM1 binding to TRPC1 for extracellular calcium entry. Consequently, activation of the STIM1-TRPC1 route facilitates PQ-induced EMT for pulmonary fibrosis. Correspondingly, PQ-poisoned patients exhibit specifically reduced blood calcium levels, which is correlated with the severity of PQ poisoning. Taken together, our results demonstrate that PQ is the agonist of STIM1 that induces extracellular calcium entry, increases intracellular calcium levels and thus promotes EMT in AT II cells, which would provide another important molecular target for treating PQ poisoning.
Phenotypic Bacterial Isolates, Antimicrobial Susceptibility Pattern and Associated Factors among Septicemia Suspected Patients at a hospital, in Northwest Ethiopia. Prospective cross- sectional study
Authors: Belew Habtamu , Tamir Workineh , Dilnessa Tebelay , Mengist Abeba
Published: April 2022

Background
Septicemia is a life-threatening infection when pathogenic bacteria infiltrate the bloodstream, leading morbidity and mortality in Ethiopian hospital patients. Multidrug resistance is a therapeutic challenge among this patient and has a paucity of data in the hospitals. Therefore, this study aimed to assess the bacterial isolates, antimicrobial susceptibility pattern, and associated factors among septicemia suspected patients.
Methods
Prospective cross-sectional study was conducted among 214 septicemia suspected patients from February to June 2021 a hospital in northwest, Ethiopia. Blood samples were collected aseptically and processed to identify bacterial isolates by using different standard microbiological procedures. Antimicrobial susceptibility pattern was performed using the modified Kirby Bauer disc diffusion on Mueller Hinton agar. Epi-data V4.2 was used to enter data and SPSS V25 for analysis. The variables were assessed using a bivariate logistic regression model with a 95% confidence interval, and declared statistically significant; P-value was < 0.05.
Results
The overall bacterial isolates was found 45/214 (21%) in this study. Gram-negative and positive bacteria were 25/45(55.6%), 20/45(44.4%) respectively. The most common bacterial isolates were Staphylococcus aureus12/45 (26.7%), Klebsiella pneumonia8/45(17.8%), Escherichia coli 6/45 (13.3%). Gram-negative bacteria showed susceptible to amikacin (88%), meropenem, imipenem (76%), but resistance to (92%) ampicillin, (85.7%) amoxicillin-clavulanic acid. S.aureus (91.7%) resistance to Penicillin, (58.3%) cefoxitin and (75%) susceptible to ciprofloxacillin. S.pyogenes and S.agalactia were (100%) susceptible to Vancomacin. Multidrug resistance was found in 27/45(60%) of the bacterial isolates. The main predictors related to patients suspected of septicemia were prolonged hospitalization (AOR = 2.29, 95% CI: 1.18, 7.22), fever (AOR = 0.39, 95%CI: 0.18, 0.85) and length of hospital stay (AOR = 0.13, 95%CI: 0.02, 0.82).
Conclusions
Bacterial isolates among septicemia suspected patients were high. The majority of the bacterial isolates were multidrug-resistant. To prevent antimicrobial resistance, specific antibiotic utilization strategy should be applied.
Mapping of national population-based surveys for better reporting of health-related indicators in the Eastern Mediterranean Region
Authors: Riazi-Isfahani Sahand , Doctor Henry V , Aly Eman , Basha Hanem Mohamed , Majdzadeh Reza , Rashidian Arash
Published: April 2022

Background
Improving the quality of data to generate health-related indicators is important for effective monitoring of progress towards universal health coverage (UHC). In consultation with Member States, stakeholders and experts, World Health Organization (WHO) developed a framework for health information systems and 68 regional core health indicators to support Member States to effectively track health issues. These core health indicators come from two main data sources: routine or institution-based and population-based surveys. The aim of this study is two-fold: to map out population-based surveys that are expected to be conducted to generate data for the health-related indicators including Sustainable Development Goal (SDG) 3 indicators; and to propose a timetable for conducting national population-based surveys in the Region.
Methods
The study was conducted in six phases: 1) Selecting survey-based indicators; 2) Extracting and comparing relevant survey modules; 3) Identifying sources of data for the indicators; 4) Assessing country status in reporting on core health indicators; 5) Designing survey timetable; and 6) Review and confirmation of the results by the experts.
Results
Forty-four out of 68 (65%) regional core health indicators and two out of 11 (18%) SDG 3 indicators use data from population-based surveys. The Health Examination Survey (HES) could cover 65% of the survey-based indicators. A suggested 10-year timetable was designed for conducting national population-based surveys for the countries in the Region.
Conclusions
We have proposed an optimum timetable for conducting national population-based surveys that can be modified depending on the local context, technical expertise and available resources. To reliably report on all the core health indicators, each country could devise a timetable for population-based surveys by considering several factors such as national health priorities, financial and human capacities, and previous experiences.
Ebselen derivatives inhibit SARS-CoV-2 replication by inhibition of its essential proteins – PL pro and M pro proteases, and nsp14 guanine N7- methyltransferase
Authors: Zmudzinski Mikolaj , Rut Wioletta , Olech Kamila , Granda Jarosław , Giurg Mirosław , Burda-Grabowska Małgorzata , Kaleta Rafał , Zgarbova Michala , Kasprzyk Renata , Zhang Linlin , Sun Xinyuanyuan , Lv Zongyang , Nayak Digant , Kesik-Brodacka Malgorzata , Olsen Shaun K. , Weber Jan , Hilgenfeld Rolf , Jemielity Jacek , Drag Marcin
Published: April 2022

Proteases encoded by SARS-CoV-2 constitute a promising target for new therapies against COVID-19. SARS-CoV-2 main protease (Mpro, 3CLpro) and papain-like protease (PLpro) are responsible for viral polyprotein cleavage – a process crucial for viral survival and replication. Recently it was shown that 2-phenylbenzisoselenazol-3(2H)-one (ebselen), an organoselenium anti-inflammatory small-molecule drug, is a potent, covalent inhibitor of both the proteases and its potency was evaluated in enzymatic and anti-viral assays. In this study, we screened a collection of 34 ebselen and ebselen diselenide derivatives for SARS-CoV-2 PLpro and Mpro inhibitors. Our studies revealed that ebselen derivatives are potent inhibitors of both the proteases. We identified three PLpro and four Mpro inhibitors superior to ebselen. Independently, ebselen was shown to inhibit the N7-methyltransferase activity of SARS-CoV-2 nsp14 protein involved in viral RNA cap modification. Hence, selected compounds were also evaluated as nsp14 inhibitors. In the second part of our work, we employed 11 ebselen analogues – bis(2-carbamoylaryl)phenyl diselenides – in biological assays to evaluate their anti-SARS-CoV-2 activity in Vero E6 cells. We present their antiviral and cytoprotective activity and also low cytotoxicity. Our work shows that ebselen, its derivatives and diselenide analogues constitute a promising platform for development of new antivirals targeting the SARS-CoV-2 virus.
Endoscopic variceal obturation and retrograde transvenous obliteration for acute gastric cardiofundal variceal bleeding
Authors: Lee Han Ah , Kwak Jungwon , Cho Sung Bum , Lee Young-Sun , Jung Young Kul , Kim Ji Hoon , Kim Seung Up , An Hyonggin , Yim Hyung Joon , Yeon Jong Eun , Seo Yeon Seok
Published: April 2022

Background/Aims: We compared the efficacy of endoscopic variceal obturation (EVO) and retrograde transvenous obliteration (RTO) in acute cardiofundal variceal bleeding.Methods: Patients with acute cardiofundal variceal bleeding treated with EVO or RTO at two academic hospitals were included.Results: Ninety patients treated with EVO and 86 treated with RTO were analyzed. The mean model for end-stage liver disease score was significantly higher in EVO group than in RTO group (13.5 vs. 11.7, P=0.016). The bleeding control rates were high (97.8% vs. 96.5%), and the treatment-related complication rates were low in both EVO and RTO groups (2.2% vs. 3.5%). During the median follow-up of 18.0 months, gastric variceal (GV) and esophageal variceal rebleeding occurred in 34 (19.3%) and 7 (4.0%) patients, respectively. The all-variceal rebleeding rates were comparable between EVO and RTO groups (32.4% vs. 20.8% at 2-year, P=0.150), while the GV rebleeding rate was significantly higher in EVO group than in RTO group (32.4% vs. 12.8% at 2-year, P=0.003). On propensity score-matched analysis (71 patients in EVO vs. 71 patients in RTO group), both all-variceal and GV rebleeding rates were significantly higher in EVO group than in RTO group (all P <0.05). In Cox regression analysis, EVO (vs. RTO) was the only significant predictor of higher GV rebleeding risk (hazard ratio 3.132, P=0.005). The mortality rates were similar between two groups (P=0.597).Conclusions: Both EVO and RTO effectively controlled acute cardiofundal variceal bleeding. RTO was superior to EVO in preventing all-variceal and GV rebleeding after treatment, with similar survival outcomes.
Endoscopic sphincterotomy and endoscopic biliary stenting do not affect the sensitivity of transpapillary forceps biopsy for the diagnosis of bile duct adenocarcinoma
Authors: Aoki Toshinori , Ohno Eizaburo , Ishikawa Takuya , Mizutani Yasuyuki , Iida Tadashi , Yamao Kentaro , Yamamura Takeshi , Furukawa Kazuhiro , Nakamura Masanao , Honda Takashi , Ishigami Masatoshi , Yatsuya Hiroshi , Kawashima Hiroki
Published: April 2022

[Background] The pathological evaluation of tissues with cholangitis is considered difficult, which can often occur after endoscopic sphincterotomy (EST) and endoscopic biliary stenting (EBS). This study aimed to evaluate the influence of a history of EST and EBS on the sensitivity of transpapillary forceps bile duct biopsy (TB) for bile duct adenocarcinoma.[Methods] This retrospective study included consecutive cases of bile duct adenocarcinoma in which TB was performed before July 2020 until the number exceeded that required to support statistical and noninferiority analyses of the sensitivity of TB between patients with and without each variable. The incidence of postprocedural adverse events related to each factor was also investigated.[Results] Overall, 280 samples were required in each group, and 437 subjects (792 samples) were included. The sensitivity of TB was 63.6% for the subjects and 59.6% for the biopsy samples. For the biopsy samples, the sensitivity did not differ significantly between samples from patients with and without a history of EST (59.1% vs. 58.9%, P=0.952) and EBS (62.1% vs. 55.4%, P=0.065). The sensitivity was significantly higher for samples from patients with jaundice (67.9% vs. 57.0%, P=0.008). There were significantly fewer procedure-related adverse events in patients with a history of EST (10.8% vs. 19.0%, P=0.017) and EBS (12.0% vs. 21.7%, P=0.005).[Conclusions] A history of EST or EBS did not influence sensitivity of TB but significantly decreased the incidence of adverse events. To safely and reliably perform TB to diagnose bile duct adenocarcinoma, planning, including for EST and EBS, is necessary.
GDF15 negatively regulates RGS16 involving in abnormal lipid metabolism in IVF-ET male mice offspring
Authors: Liu Jingliu , Zhu Yichen , Zhu Dan , Shi Yajun , Lu Likui , Li Weisheng , Li Lingjun , Zhou Xiuwen , Yang Hao , Wang Bin , Sun Miao
Published: April 2022

Background
In vitro fertilization and embryo transfer (IVF-ET) is now widely used as a routine assisted reproductive technology (ART) procedure, and the long-term health outcomes of IVF-ET offspring are of great concern. A growing body of research suggests that children conceived through IVF-ET may be at increased risk for metabolic syndrome, type 2 diabetes, and cardiovascular disease.
Methods
An IVF-ET mouse model was established. Body weights and the principal organs were weighed, and organ/body weight indexes were calculated. The glucose metabolism levels were assessed by glucose tolerance test (GTT), insulin tolerance test (ITT), and pyruvate tolerance test (PTT). The quantitative real-time PCR (RT-qPCR) technique was performed to determine the gene expression profiling in livers; HepG2 cells were transfected with either interfering RNA or overexpression plasmids to investigate the gene functions. mRNA and protein expression of relevant genes was verified by RT-qPCR and protein immunoblotting.
Results
Compared with the natural mating control group, male IVF-ET offspring showed: Higher body, liver, and epididymal white adipose tissue (eWAT) weight; Disrupted glucolipid metabolism with abnormal GTT, ITT, and PTT; Significantly decreased GDF15 expression along with increased expression of RGS16. Furthermore, phosphorylation of ERK1/2 and AKT were significantly reduced in the IVF-ET group. In vitro HepG2 cell experiment showed that knockdown of GDF15 caused an abnormal increase in RGS16 expression and decreased phosphorylation of ERK1/2 and AKT, accompanied by increased lipid deposition; In contrast, overexpression of GDF15 reduced expression of RGS16. Simultaneous knockdown of both GDF15 and RGS16 reversed lipid deposition in HepG2 cells.
Conclusion
Down-regulation of GDF15 expression in liver tissues of IVF-ET male offspring results in elevated expression of RGS16, which causes the weakening of the downstream ERK1/2 and AKT phosphorylation pathways, leading to increased activity lipid deposition and abnormal lipid metabolism in the liver of IVF-ET male offspring. It is suggested that GDF15-RGS16-p-ERK1/2/p-AKT pathway plays a crucial role in liver lipid deposition in IVF-ET male offspring and could be a potential therapeutic target.
Sleep Pattern, Healthy Lifestyle and Colorectal Cancer Incidence
Authors: Chen Jie , Chen Nanqian , Huang Tao , Huang Ninghao , Zhuang Zhenhuang , Liang Hailun
Published: April 2022

Objective
Lifestyle factors have been associated with colorectal cancer (CRC) risk. The majority of previous studies did not consider the complex nature of sleep pattern. We aimed to examine the relationship between sleep pattern and CRC events.
Methods
The study included 502,504 individuals in the UK Biobank. A healthy sleep score was created by combining chronotype, sleep duration, insomnia, snoring, and excessive daytime sleepiness. Healthy sleep factors were defined as sleep 7 to 8 h per day; never/rarely or sometimes insomnia symptoms; no snoring; no excessive daytime sleepiness. Healthy lifestyle scores were developed by combing physical activities, diet, drinking, smoking and obesity. Using Cox proportional hazards regression, we computed hazard ratios (HRs) to examine the associations of the sleep patterns, healthy lifestyle with incidence of CRC.
Results
The healthy sleep score was inversely associated with CRC events. The HRs for CRC were 0.884 (95% CI, 0.863–0.906) and 0.927 (95% CI, 0.899–0.956) for a 1-point increase in the healthy sleep score among males and females. When analyzing sleep components, sleeping 7 to 8 h/d, no frequent insomnia, no snoring, and no frequent daytime sleepiness were independently associated with 10%, 14%, 11%, and 14% lower risk of CRC. Healthy lifestyle scores were also inversely associated with the incidence of CRC across all models.
Conclusions
Sleep pattern and lifestyle were significantly correlated with the risk of CRC. The healthier the lifestyle and sleep pattern were, the lower the CRC risk was.