bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Oil Recovery in Naturally Fractured Reservoirs: State of the Art and Future Perspectives
Authors: Delamaide Eric , Batôt Guillaume , Alshaqsi Abdulaziz , Alkindy Abdullah , Al-Mejni Rifaat
Published: March 2022

In Naturally Fractured Reservoirs (NFRs), production rate quickly drops once the oil in the fractures is produced. Indeed, high connectivity of the fracture network soon requires the application of IOR/EOR methods to unlock production from the low permeability matrix blocks which bear the major part of the oil in most carbonate-NFRs. This paper is intended as a thorough review of the EOR field tests in such reservoirs and discussion of the physical mechanisms at stakes.

To the best of our knowledge there has never been any review dedicated to EOR methods specifically applied to NFRs. After a description of the main mechanisms involved in these processes this paper proposes to revisit the EOR field tests performed in carbonate-NFRs based on the following technologies: Gas injection, thermal- and solvent-assisted production, and finally chemical EOR, the latter being seen as a way to improve the kinetic of oil recovery from the matrix: foam, surfactant-polymer, low-salinity and hybrid processes, including a discussion of the remaining challenges to successfully apply these more recent technologies in the field.

Beyond the fact that NFRs are quite interesting because of their complexity, they account for a large part of the world's oil proven reserves, approximatively 20%. Even though this value should be taken with caution, as it depends on the NFRs definitions and their characterizations, there are clearly significant amounts of oil trapped inside these reservoirs. For that reason, they are of great interest, both in terms of understanding and economical consideration for oil companies willing to get the most out of their fractured fields. Even when based on sound static and dynamic characterizations, production optimization of NFRs remains challenging: classical flooding mainly produces the oil contained in the fractures during the early stages of the field development. The high connectivity of the different levels of the fracture network along with the low permeability of the oil-bearing matrix blocks, combined with the often oil-wet nature of carbonate formations, are the three main factors at plays preventing the production of the remaining oil from the matrix blocks. Design of dedicated EOR solutions are needed and learning from past experiences through the review and analyze of the past field trials is of great value to that purpose.

This review and discussion will allow engineers to get an extended and up to date understanding of the features and drawbacks of the main EOR methods which could be applied to NFRs, and also provide some guidance in the selection or design of the best suited EOR solution to a specific naturally fracture carbonate field.
Foam for High Temperature and Ultra-High Salinity Conditions: Its Displacement Efficiency Under Different Permeability Heterogeneity
Authors: Yuan Chengdong , Pu Wanfen , Varfolomeev Mikhail A. , Hui Jian , Zhao Shuai , Zheng Xiaojie , Timofeeva Anastasia A.
Published: March 2022

Foam flooding is one of promising enhanced oil recovery (EOR) methods for waterflooded reservoirs due to its good mobility control capability. However, its application in high-temperature and high-salinity reservoir has always been a challenge. This work presents salt-tolerant foam that can be used at about 100 °C under the salinity of more than 200000 mg/L (Ca2+ + Mg2+ >10000 mg/L). Its displacement efficiency was evaluated at different permeability heterogeneity conditions.

The surfactant (foaming agent) solution was prepared using reservoir formation water (total salinity 204672 mg/L, Ca2+ + Mg2+ 11480 mg/L) obtained from a reservoir in Tarim Basin, China. The displacement efficiency of foam was investigated in different permeability conditions (35.47, 72.72, 165.75, 265.28, 410.73, 600.38, and 950.11 mD) using single-core flooding experiment and in different permeability heterogeneity (permeability max-min ratio of 3.34, 6.62, 9.22, and 11.98) using parallel-core flooding experiments (one high-permeability core and one low-permeability core). For all flooding experiments, nitrogen foam was used by co-injection of nitrogen and surfactant solution.

For all permeability conditions in single-core flooding experiments, after water flooding with a 98% water cut, the injection of foam could increase the injection pressure. Foam injection together with its subsequent water flooding could yeild an additional oil recovery of 11.73, 12.35, 12.8, 13.04, 15.45, 16.04, and 17.51% under the permeability of 35.47, 72.72, 165.75, 265.28, 410.73, 600.38, and 950.11 mD, respectively. Obviously, the yielded additional oil recovery increased with permeability. Under the permeability max-min ratio of 3.34, 6.62, and 9.22, an addtition oil recovery can be yielded from both high- and low-permeability cores, but the additional oil recovery from low-permeability core was higher. This implies that the injection of foam can not only improve displacement efficiency after water flooding, but also can effectively increase flow resistance in high-permeability core, and thus improving oil recovery in low-permeability core. However, when the permeability max-min ratio was increased to 11.98, the oil in low-permeability core cannot be mobilized even after foam injection, which means that foam injection can effectively work only in a certain permeability heterogeneity condition. When permeability heterogeneity is strong, enhanced foam should be considered to increase the strength of foam using polymer (only for low temperature), gel or nanoparticles, etc.

The obtained results show that the developed foam formulation has a great potential for improving displacement efficiency and sweep efficiency in water-flooded heterogenous reservoirs with very high temperature and ultra-high salinity.
Autonomous Gas Shut-Off in Gas Oil Gravity Drainage Reservoir, Sultanate of Oman
Authors: Al Shibli Abdullah , Al Maamari Hilal , Griborio Csimiro , Adeponle Simeon , AL Wahaibi Hamed , AL Zuhaimi Khalid , Al Saadi Hamoud , Bdair Mohammad
Published: March 2022

FH is one of the largest oil producing assets in the Sultanate of Oman. With more than 30 years of production, the current recovery mechanism from the naturally fractured carbonates is relying 80% on the gas oil gravity drainage (GOGD) process whereby produced formation gas is re-injected into the reservoir for pressure maintenance. Optimizing the GOGD process and hence maximizing oil production is the main objective in FH WRFM strategy. Controlling the formation gas production from subsurface and surface gas capacity handling are the main challenges to unlock reservoir oil potential.

Down hole gas shut-off technology has been proposed in 2018 to control high GOR (+1000) producers and minimize formation gas production for more efficient GOGD process. The technology provides a mean for blocking formation gas through autonomous valve compartments installed within a production liner in the open hole section of the horizontal wells. The independent compartments are positioned against the open fractures and the inflow from the fractures to the open hole is controlled autonomously based on the fracture GOR. The valves in each compartment is designed to close against low viscosity fluid (gas) and allow high viscosity (liquids) to flow into the liner.

Screening process has identified up to 80 candidates for the technology with a potential gain of up to 6% of the total field production. Formation GOR, well uptime and lateral fracture interference are the top criteria for candidate selection. The full field deployment started in July 2018 after a six months trial period with a target to complete the full scope by 2022.

90% reduction in formation gas has been observed in the wells where gas shut-off technology have been installed. A sustainable oil gain up to 50% has been realized after the gas reduction from the first 14 candidates. In addition to that, a significant improvement in the well uptime from 40% to 80% has also been recognized due to low producing GOR after the technology deployment. The technology has also enabled the re-instatement of long term closed-in wells due to high producing GOR.

The originality of the technology lies on the ability of the downhole inflow control valves to react to the gas autonomously and successfully shut off the gas contribution and the same time allow oil to flow.
Hazardous Events Prevention and Management Through an Integrated Machine Learning and Big Data Analytics Framework
Authors: Cadei Luca , Rossi Gianmarco , Lancia Lorenzo , Loffreno Danilo , Corneo Andrea , Milana Diletta , Montini Marco , Purlalli Elisabetta , Fier Piero , Carducci Francesco , Nizzolo Riccardo
Published: March 2022

This paper reports the development and tests of an advance methodologies to predict Upstream plant risky events, such as flaring, applying an integrated framework. The core idea is to exploit Machine Learning and big data analytics techniques to tackle and manage both major upsets that would lead to significant inefficiency and loss. The tool is developed for complex upstream production system, where upset could be caused by a huge amount of heterogeneous factors, exploiting data driven monitoring systems to identify the weak signals of the upcoming events.

The framework proposed is mainly composed by a strong pipeline divided in 3 modules operating before (predictive phase), during and after the event. The former aims to reduce the probability of an event, the second works on the severity and the third one has a dual function: reporting upsets and feedback gathering system to be used to further improve the analytics implemented. The Predictive component alerts operators when it recognizes a dangerous pattern among the parameters considered. The other two components can support this one and can be exploited to detect early signs of deviations from the proper operating envelope, while predictive performances are not satisfying. Moreover, during an event occurrence, operators can promptly identify the causes of the upset through the entire production system. This allows a faster reaction and consequently a significant reduction in magnitude. The solution proposed provides 2 complementary methodologies:

an agnostic anomaly detection system, helping to map plant functional unit anomalous behavior, as a dynamic operating envelope, and identifying the most affected ones;

A real time root-cause analysis, as a vertical solution, obtained learning from the monitoring of the different specific functional unit;

The tool is also able to provide an automatic event register using information provided by the root-cause system, including operator feedbacks that will improve the performances of each module of the framework.

The entire pipeline developed has been applied on-line, working with real time data coming from an operating oilfield, with special focus on blowdown and flaring system. The robust architecture generated is able to overcome some main issues related to the complexity of Upstream production assets such as lack of data, quick dynamic of physical phenomena analysed and randomness of upsets. The first test demonstrates that the tool accuracy allows to identify and suggest actions on 35% of the most dangerous flaring events occurring. Moreover, the effectiveness increase significantly proving a real time root-cause analysis considering both strong and weak signals that cause dangerous overpressures through the treatment plant.
ESP Performance Enhancement and Premature Failure Reduction Through Esp Equipment Reliability Project in a West Kuwait Field - Case Study From Kuwait
Authors: Hassan Mohmaed , Nour Ahmed , Abdul-Aziz Wejdan , Al-Yaqout Thanyan , Al-Azmi Ali , Al-Hashash Budoor , Al-Methen Badriya , Abu-Eida Abdullah , Munoz Jorge , Al-Suwailem Lulwa
Published: March 2022

Most of wells in the major oil fields of West Kuwait Asset are producing with Electrical Submersible Pump (ESP). During 2012- 2013, the ESP premature failures reached high percentages of up to 30% of ESP population with high deferred oil.

In order to enhance the ESP performance and reduce the number of premature failed ESP, FD (WK) has initiated ESP Equipment Reliability Project in 2014. The main objective was to define a proper workflow that will be capable to identify the root cause of ESP premature failures, find the way forward and mitigation actions to overcome the issue.

All ESP business partners from KOC and service providers were involved in the project. Series of technical workshops following the API and KOC standards were conducted by the team members to analyze the ESP performance and premature failures where the team was able to define analytical workflow in the early review sessions to conduct the required work.

The workflow takes in consideration the reservoir parameters and conditions, ESP performance with all tags and signatures, ESP systems from the overhead electrical line or generator, surface equipment down to ESP down hole equipment specifications, installation and pull-out procedures, and ESP operating conditions. Also attending the tear down of the failed wells to ensure the vendors procedures and the reported findings. In-addition, well models were utilized to find the deviation between the design and actual parameters and surface network model was utilized to define the impact of the pipeline issues on the ESP performance.

Based on this study, the root cause of the ESP premature failures were found to be mainly due to; Power Quality, Sour condition, External sand source, Down hole emulsion, and some Equipment quality / specifications that were not designed to handle the down hole conditions of UG wells.

A mitigation plan and list of recommended actions were concluded and implemented with a measure of the outcome and results in addition to some modifications that were applied within time.

The project shows excellent results with time where the premature failures reduced from 30% in year 2012- 2013 to 12% in year 2018. Also the ESP showed enhanced performance over time. Extra room for improvement can be chieved by enhancing the power quality of the overhead lines and generators.

Applying the mentioned workflow with the proper project structure form will help ESP stakeholders to identify the root cause and not the failure reason, Hence reduce premature failures. This will lead to reduce deferred oil, reduce cost per barrel, and avoid equipment compensation fees.
Innovative Perforating Strategy Saves Completion Cost and Improves Production in Tight Gas Sandstone Reservoir
Authors: Almulhim Abdulrahman , Tarihoran Anton , Hamid Saad , Zaouali Zouhir
Published: March 2022

Tight Gas reservoirs require fracturing as part of the reservoir exploitation strategy. The quality of perforations play an important role in establishing effective contact with the reservoir prior to fracturing. Several perforating technologies have been used and evaluated to optimize operations and saving completion costs. This practice has provided a wealth of data to analyze the most efficient strategy for tight gas reservoirs. An optimized perforating method has been implemented recently in fields that traditionally required hydraulic fracturing to bypass drilling damage and produce commercially.

Combining deep penetration charges with an instantaneous underbalance is the key ingredient for this method. The method results in achieving maximum reservoir contact, away from washouts, breakouts and damaged zone; thereby, delivering clean perforation tunnels and higher entrance hole diameter. In cases, where the productivity is limited by extremely low permeability and hydraulic fracturing becomes inevitable, the benefits extend to the fracturing operation in terms of lowering the breakdown and treatment pressures, improved treatment rates, effective proppant placement and minimizing the likelihood of pre-mature screen out. The paper outlines the detailed workflow including candidate recognition, treatment design, execution and evaluation leading to significant savings in operating expenditure. The paper also provides a comprehensive comparison with other perforating practices and evaluate their effectiveness.

The results obtained through deployment of this method on several wells are extremely encouraging. The wells were able to produce naturally, exceeding production expectations. As a result, significant time and cost savings were realized by eliminating subsequent production operations and well intervention work. The pressure transient analysis showed low skin pointing towards insignificant near wellbore damage.

This innovative method improves the way perforations are performed. Encouraged by this success, additional candidates are being evaluated with similar approach with an objective to optimize completion costs and improving initial production.
Field Application of an Associative Polymer Reveals Excellent Polymer Injectivity
Authors: Herbert Hommer , Roland Reichenbach-Klinke , Russell Giesbrecht , Prapas Lohateeraparp , George Herman , Kahnery Mai
Published: March 2022

Chemical EOR flooding using hydrolyzed polyacrylamide (HPAM) is considered nowadays a state-of-the-art tertiary recovery process and has been conventionally applied on a full-field scale worldwide. The addition of these standard polymers improves the mobility of the injected fluid and thus maximize sweep; however, application is only limited to mild reservoir temperatures and low brine salinity ranges. Therefore, a more thermally stable and more resistant "associative polymers" were derived, by incorporating specific hydrophobic groups into the HPAM polymer backbone, to offer performance advantages with regards to viscosifying efficiency and salt tolerance when compared to the standard HPAM. However, only a handful of field cases were reported in the literature. Thus, this paper will present the unique application of this associative polymer technology in a field pilot for one of the major E&P companies and discusses the corresponding lab evaluations leading up to the field trial.

To confirm the advantages of using associative polymer over of standard HPAM, rheology and filterability measurements were conducted. Moreover, linear coreflood experiments in presence of oil have been performed at target field conditions (low temperature and higher salinity) with various polymer concentrations. The resistance factors measured in the coreflood experiments indicated that 750 and 1,250 ppm of associative polymer and HPAM, respectively, are adequate to deliver the required mobility ratio of 1 and accordingly the oil recovery can be similar for the two different polymers at these concentrations. Moreover, dynamic adsorption measurements conducted at the same polymer concentration reveal a smooth propagation of the associative polymer through the porous medium. Based on these findings, it is concluded that the associative polymer offers a significant performance advantage over the HPAM due to the lower polymer dose required to achieve the target performance.

After successful lab evaluations and in preparation for a multi-well pilot, a field injectivity trial was planned accordingly to test the propagation of the synthesized polymer in the reservoir. Subsequently, the selected associative polymer was successfully injected into the reservoir over a period of two months in two injectors at a steady injection rate of 50 and 300 m3/d. The measured well head pressures of the two injection wells was stable for the entire test duration, indicating a good polymer injectivity with no observed formation plugging.

This newly developed associative polymer was proposed to the field's operator as a promising alternative solution to unlock additional reserves increase oil recovery and a full-field polymer flood expansion is planned next. To our knowledge, this is one of the few reported field trials with associative polymers and should facilitate field implementation of this technology.
Cost Efficient Polymer Full Field Development by Fast Tracking Nap Concept in Horizontal Polymer Injectors
Authors: Saadi Faisal , Al Jumah Ali , Harthy Khalfan , Khaburi Saja , Battashi Fathiya
Published: March 2022

This paper will discuss a polymerflood field application, the data has been gathered, and the new project designed specifically to test the concept of Nothing-Alternating-Polymer (NAP) mechanism, in a current Polymer flood pattern, in a horizontal wells environment. This specific project will be utilized to fast track the implementation of the NAP concept, and accelerating Fullfield development, and highlight the associated benefits from a project's perspective, leading towards attractive, competitive development cost, and flexible operating conditions.
Using Autonomous Inflow Control Device Completion to Manage Gas Breakthrough Challenges
Authors: Nugraha Ikhsan , Widjaja Danang , Raffn Anne Gerd , Mathiesen Vidar
Published: March 2022

During the production of horizontal oil wells, it is crucial to normalize the drawdown once gas breakthrough has occurred. This challenge must be addressed either mechanically or chemically to reduce the gas-oil ratio. Unfortunately, without the use of inflow control devices (ICDs) this can result in loss of oil production. This challenge can potentially be addressed by implementing an advanced inflow control valve completion to suppress the gas-oil ratio (GOR) and maintain oil production.

Uneven inflow in a horizontal oil well will usually occur due to a pressure drop in the liner, reservoir fractures and heterogeneities. In fields with free gas, this will cause gas coning and breakthrough leading to a high GOR. As the breakthrough expands, the oil production is reduced due to excessive gas production. Passive ICDs have shown that oil production can be increased. Conventional ICDs are not able to shut off the unwanted gas and water production completely. The newest generation of self-regulated ICDs (SRICDs), utilizes valves where their movement is governed by fluid properties being produced, which autonomously shut off the gas and maximize oil recovery.

This paper presents the SRICD technology design evolution to match the reservoir challenges, installation processes and well performance comparison before and after completion deployment. A near wellbore inflow simulator was also used to support and model the completion placement, productivity and evaluate the completion performance together with the well production data. The well completion installation and production optimization was successful, and a significant reduction of the GOR was achieved.
Offshore Oil & Gas Upstream Production Hubs, a Way to Success in Fields Development
Authors: Gassert Michael , Castellitto Tommaso , Inzerillo Gianvito , Citi Gianfederico , Dell'Orto Lorenzo
Published: March 2022

Objectives/Scope

The paper intends to review the most recent offshore oil & gas field developments where production hubs have been introduced and technical solutions are being developed in order to produce all reservoirs of a same block or area towards a central hub facility.

Methods, Procedures, Process

Different success stories among the most recent developments will be analyzed in the paper both for oil developments and gas developments: particular attention to the design basis, design envelopes and expected flexibilities will be highlighted, planning for future tiebacks will be discussed and their design and features will be addressed. The paper will touch process, safety and plant design aspects for a central processing floater or plant as well as subsea and wellhead platform tiebacks to the Hub.

Results, Observations, Conclusions

At the present time and with the today qualified technologies, as far as oil developments are concerned, it is deemed possible to develop from a central hub an area exceeding 100 km of radius even in deepwater and probably more in conventional waters.

As far as gas developments are concerned and with the adequate design provisions and technics it is probably possible to develop from a central hub a complete basin covering distances above 250-300 km and boosting production up to distant midstream facilities.

Combined oil and gas offshore hubs in areas where both oil and gas assets are to be developed demonstrate to be very interesting and efficient ways of developing an extended area through efficient synergies in tie backs and processing facilities.

Please explain how this paper will present novel (new) or additive information to the existing body of literature:

The paper is based on real case studies and both: extensive work ongoing intended to further utilize the recently developed hubs as well as extensive design activities for the upcoming greenfield developments.
Parametric Investigation of the Gas-Assisted Gravity Drainage Technique
Authors: Mishra Shubham , Sridhar Garud , Ibrahim Muhammad , Aggarwal Akshay , Reddy Vinil , Saikia Bikash , Rao Dandina
Published: March 2022

Whereas the application of EOR methods is estimated to recover nearly 6 out of the 9 trillion barrels initially in-place globally, there is a high chance of failure of an EOR project due to lack of characterization, operational challenges, misplaced concept, etc. It is extremely challenging to reduce these uncertainties and hence the success of an EOR project is a big question, except for the case in which the method is relatively immune to such uncertainties. The gas-assisted gravity drainage (GAGD) technique is an excellent example of such a method where the recovery is enhanced by concepts of gravity and fluids' density differences and thus relatively safer from execution failures. It has been proposed as a viable alternative to, and improvement over, conventional gas injection techniques such as water-alternating-gas (WAG) and continuous gas injection (CGI), because of its higher chance of success.

The success of GAGD hinges very strongly on the interplay between in-situ reservoir properties (rock and fluid parameters) and the range of operating parameters imposed. In the primary GAGD configuration, gas is injected in the crest, and oil is withdrawn (produced) via a horizontal well at the bottom of the structure. In this study, a simplified black-oil numerical simulation framework has been developed to assess the viability of the GAGD process in candidate reservoirs with focus around lower permeability reservoirs coupled with hydraulically fractured rocks. Incremental production over natural depletion and hydraulic fractured cases have been used as the assessment criterion.
What is the Optimum Wettability for Oil Recovery Through Waterflooding?
Authors: Alnoush Wajdi , Shaat Abdullah , Alyafei Nayef
Published: March 2022

This work provides a review of and answers the critical question about the optimum wettability for oil recovery through conventional and low salinity waterflooding (LSW) methods. As the answer is not straightforward, this work investigates conflicting views that justify conclusions and provide comparisons between different rock types and conditions. Parameters affecting oil recovery are linked to wettability to identify the optimum state for different waterflooding schemes.

Relying solely on core-based analysis or any other method is argued to be inconclusive without considering the conditions of core handling and testing, pore-network structure, contact angle tests, and field-scale considerations. Therefore, optimum wettability for oil recovery is a multivariate question; thus, comprehensive conclusions should come from cross-factor analysis rather than isolating certain factors. This work provides a reference for researchers to approach this dichotomy through an overview of previous works in this area.
MAGNet: A camouflaged object detection network simulating the observation effect of a magnifier
Authors: Jiang Xinhao , Cai Wei , Zhang Zhili , Jiang Bo , Yang Zhiyong , Wang Xin
Published: March 2022

In recent years, protecting important objects by simulating animal camouflage has been widely used in many fields. Therefore, camouflaged object detection (COD) technology has emerged. COD is more difficult than traditional object detection techniques because of the high degree of fusion of camouflaged objects with the background. In this paper, we strive to more accurately identify camouflaged objects. Inspired by the use of magnifiers to search for hidden objects in pictures, we propose a COD network that simulates the observation effect of a magnifier, called the MAGnifier Network (MAGNet). Specifically, our MAGNet contains two parallel modules, i.e., the ergodic magnification module (EMM) and the attention focus module (AFM). The EMM is designed to mimic the process of a magnifier enlarging an image, and AFM is used to simulate the observation process in which human attention is highly focused on a region. The two sets of output camouflaged object maps are merged to simulate the observation of an object by a magnifier. In addition, a weighted key point area perception loss function, which is more applicable to COD, is designed based on two modules to give higher attention to the camouflaged object. Extensive experiments demonstrate that compared with 14 cutting-edge detection models, MAGNet can achieve the best comprehensive effect on eight evaluation metrics on the public COD dataset, and the segmentation accuracy is significantly improved. We also validate the models' generalization ability on a military camouflaged object dataset constructed in-house. Finally, we experimentally explore some extended applications of COD.
Hails in Ny Alesund, Svalbard atmospheric vertical structure and dependence on circulation
Authors: Nuncio Murukesh , Nandanan Naveen , Acharya Asutosh , Chatterjee Sourav , Vidya P.J
Published: March 2022

Hail observed at Ny Alesund, Svalbard in Arctic during December - February 2018-19 is examined along with the atmospheric circulation patterns. When hail was noticed, surface warming and southwesterly – westerly winds were noticed. Atmospheric circulation pattern was characterised by high pressure anomaly over northwestern Europe or in the North Atlantic and represented the first and third EOF of SLP anomalies north of 40N. EOF-2, even though, characterised by a high pressure anomaly over northern Europe (EOF-2) did not result in intense precipitation. Cloud as well as liquid water were higher/lower during EOF-1 and 3 / EOF-2 active phases. This is because winds travel over ocean collect more moisture as well as transport nucleating particles to Svalbard when EOF-1 and EOF-3 were active. At the same time, the West Spitzbergen current (WSC) induce a strong east west sea surface temperature (SST) gradient in the ocean west of Svalbard. A corresponding gradient in the atmospheric temperature is also maintained by the WSC in the west to east direction in the lower atmosphere. Moisture laden westerlies cross the SST gradient inducing strong frontal activity in the lower atmosphere resulting intense precipitation and hail. Human activities in Arctic as elsewhere is bound to increase. Hence, there is a need to study the intense precipitation in Arctic as well as its reasons as it can impact the Arctic environment and human activity. This calls for more continuous observations to clearly identify mechanisms and frequency of intense precipitation in the Arctic.
Antimicrobial stewardship programme: Effects and implementation challenges
Authors: Wadhwa Pankaj , Gupta Shubham Babu
Published: March 2022

Purpose: To evaluate the gaps in surgical prophylaxis practise, which maximises the use of antimicrobial medicines while staying within prescription guidelines, and to investigate the many reasons that lead to the use of various antibiotics.Methods: The research was carried out at the orthopaedic departments of Telangana's tertiary care hospitals as an observational study. This study involved 210 participants with a history of orthopaedic procedures between November 2020 and March 2021. To determine compliance with antibiotics for surgical prophylaxis. The SPSS.22 software was used to analyse the gathered data.Results: Male patients account for 120 of the enrolled patients, while female patients account for 90, making up 57.14 percent and 42.85 percent of the total patients, respectively. The pre-antibiotic regimen was followed by 67.63 percent of the prescriptions, while 32.37 percent of the prescriptions were not followed. Following surgery, an increase in the incorrect antibiotic regimen was assessed to be 77.13 percent, whereas adherence was only 22.85 percent of all patients in the research. Conclusion: To tackle the superbug menace, collaborative and multidisciplinary efforts are needed to create antimicrobial stewardship programmes in tertiary care hospitals, as the antibiotic regimen provided for prophylaxis therapy was mainly non-compliant with the stewardship programme.
Incidentally Discovered Papillary Thyroid Microcarcinoma in Patients Undergoing Thyroid Surgery for Benign Disease
Authors: de Carlos Joaquin , Ernaga Ander , Irigaray Ana , Pineda Jose Javier , Echegoyen Ana , Salvador Pilar , Anda Emma
Published: March 2022

IntroductionIncidence of thyroid carcinoma (TC) has grown significantly over the last few decades worldwide, partly due to the increase detection of small thyroid microcarcinoma (TMc). TMc are tumors with a maximal diameter ≤ 1 cm, identified during histopathology examination following a thyroidectomy performed for reasons not pertaining to malignancy. The aim of this study is to investigate the prevalence of papillary thyroid microcarcinoma (PTMc) according to the nature of benign pathology that submit patients to thyroid surgery and its trend evolution.MethodsRetrospective cohort analysis of 1815 patients who underwent total thyroidectomy for non-malignant disease from 2005 to 2020. ResultsThe mean age of subjects was 53.5 years, with a higher proportion of women (1481, 82.1%). A total of 167 PTMc (9.3%) were incidentally discovered. Multivariate logistic regression analysis shows no differences in prevalence according to sex or age in patients with PTMc compared to those with final benign histology. Multinodular goiter increases the risk of PTMc with an odds ratio of 2.2 (p=0.001) compared to Hashimoto's thyroiditis and Graves´ disease (GD). There is a statistically significant increase in the incidence of PTMc in the group operated between 2017-2020 vs. 2005-2008 (p=0.005)ConclusionOverall prevalence of PTMc in patients who underwent thyroid surgery for benign disease was 9.3%. Thyroid nodular hyperplasia was the most frequent benign pathology associated to this occult cancer as compared to Hashimoto or GD. Gender and age were not correlated with prevalence of TMc. Over the years, surgical findings of PTMc have grown, particularly in the 2017-2020 period.
Antenatal Care in Sao Tome and Principe: Beyond the Number of Visits
Authors: Vasconcelos Alexandra , Sousa Swasilanne , Bandeira Nelson , Carvalho Elizabeth , Alves Marta , Papoila Ana Luísa , Machado Maria do Céu , Pereira Filomena
Published: March 2022

Background: Newborn mortality in Sao Tome and Principe (STP) is overwhelmingly high and the antenatal healthcare (ANC) is one of the strategies to achieve its reduction. This study aimed to know which antenatal screenings are done in STP and which antenatal problems are detected. Methods: A retrospective study in which 518 pregnant women antenatal cards were reviewed between July 2016 and November 2018. Information analysed included clinical factors, laboratory tests, ultrasounds, results, and treatment. Results: Mothers’ mean age was 26.6 (SD=7.1) years old. At least one ANC visit occurred in 98.6% pregnant women and 38.7% had 8 or more. Regarding laboratory screenings, blood group was done in 64.4%, haemoglobin tested in 62.5% (first trimester) and in 29.3% (second trimester) and, urine once in 57.1% and twice in 12.2%. Antenatal problems identified in the pregnant women studied were: i) a RhD-negative phenotype (5.8%); 2) anaemia 1st trimester (36.4%) and 2nd trimester (35.5%); 3) bacteriuria (43.2%); 4) intestinal parasites (55.5%); 5) sickle cell solubility test positive (13%). Overall, 161 (53.7%) out of the 300 ultrasounds were done before the 20th week. Conclusion: In Sao Tome and Principe many pregnant women do not have access to the full spectrum of ANC recommended screenings. Maternal anaemia and bacteriuria are the main health problems that should be urgently addressed to prevent newborn morbidity and mortality in the country. Other preventive interventions as anthelmintic drugs should be debated as intestinal parasites were diagnosed in more than half of the women. Alloimmunization to RhD is also a concern due to the unaffordability of anti-D immunoglobulin in the country.
Etiologies and clinical characteristics of macular hole: an 8-year, single-center, retrospective study
Authors: Yue Huifang , Liu Chenyu , Zhang Yunda , Zhang Lijuan , Gao Zhao , Ma Tao , Zhang Ximei
Published: March 2022

Background: To investigate the etiologies and clinical characteristics of full-thickness macular hole (FTMH) cases at Shanxi Eye Hospital in North China.Methods: Patients diagnosed with FTMH who underwent surgery from 2012 to 2020 were included, and the etiologies and clinical features of MH types were analyzed in an 8-year, cross-sectional, retrospective study.Results: A total of 752 cases (776 eyes) were analyzed. The top three causes of MH were idiopathic (IMH, 64.4%), myopic (MMH, 21.1%) and traumatic (TMH, 3.7%) MH. Among these, there were significant differences in sex, age, and baseline best-corrected visual acuity (BCVA) distributions. Females predominated in the IMH and MMH groups, while males predominated in the TMH group. The IMH onset age was older than the MMH and TMH onset ages. Baseline BCVA in the IMH (Z=8.9, p<0.001) and the other group (Z=4.0, p<0.001) was significantly better than that in the MMH group. In the IMH group, females were younger, had a shorter axial length (AL), and had a worse baseline BCVA than males, while in the MMH group, there were no significant sex differences. Multivariate correlation analysis showed that a smaller hole diameter in IMH, no retinal detachment in MMH, and a younger age in TMH may result in better baseline BCVA.Conclusions: The most common MH etiologies were IMH, MMH and TMH, which contributed to differences in clinical features. Females predominated in the IMH and MMH groups, and the onset of MMH occurred 6.5 years earlier than the onset of IMH. Therefore, early fundus monitoring in females and high myopia patients is helpful for the early detection and treatment of MH.
Impedance Iterative Learning Sliding Mode Control for Robot-Assisted Bathing with Non-repetitive Trajectory
Authors: xu yuexuan , guo xin , zhang gaowei , xuan bokai , ma tianyi , liu minghe , ding qingsong , li jian , sun hao , xing qianqian
Published: March 2022

In this paper, an impedance iterative learning sliding mode control (IILSMC) scheme for robot-assisted bathing with unknown model parameters is investigated. Firstly, impedance control is not only applied to adjust the desired trajectory, but also implemented to ensure the active compliance control of the robot-assisted bathing. Furthermore, iterative learning control is designed to dynamically estimate the unknown model parameters. To release the identical initial condition of iterative learning control (ILC), the trajectory reconstruction method is proposed, such that the convergence of tracking errors can be guaranteed with random initial status. Moreover, adaptive sliding mode control (SMC) is proposed where non-parametric, external disturbances and the human-machine interaction (HMI) torque generated during the bathing process is suppressed by adaptive method. Based on the composite energy function (CEF) method, the convergence of the double closed-loop system in the time domain and iterative domain is proved. Finally, through co-simulation of MATLAB/Simulink and ADAMS, the effectiveness and superiority of the control strategy proposed in this paper is jointly verified.
Range-wide genetic assessment of F. pennsylvanica reveals a high frequency of parentage from Fraxinus cultivars and extensive admixture between F. pennsylvanica and F. americana
Authors: Noakes Andi G. , Shirley Devin L. , Stanley Robert K. , Snyder Tatum , Koch Jennifer L. , ROMERO-SEVERSON JEANNE
Published: March 2022

Conservation of the gene pool of F. pennsylvanica (green ash), the species most susceptible to emerald ash borer (EAB), requires a range-wide genetic assessment of the population dynamics to guide seed collection efforts. An assessment of gene flow into natural stands from ubiquitously distributed green ash and F. americana (white ash) cultivars is also essential. We used 16 EST-SSR markers to genotype 1291 trees from 48 naturally regenerated populations of green ash, 19 green ash cultivars and 10 white ash from a Fraxinus species collection. We did not find evidence for latitudinal gradients in allele richness or higher differentiation in northern range edge populations. Analysis of population substructure revealed two major groups of green ash, one dominant in northwestern locations, one dominant in southern locations and extensive admixture in midwestern and eastern locations. We identified a third group as white ash, including 140 individuals with interspecific admixture in eastern and southern populations. We detected cultivar parentage with high confidence in 172 individuals in 34 of the 48 populations. We conclude that high dispersal capacity, broad adaptability, and gene flow from many cultivars into predominately northern regions, plays a role in the comparatively low regional population substructure in the Northwest. The high frequency of cultivar propagule dispersal and extent of interspecific admixture detected in our study suggests that under rapidly changing conditions, local populations may or may not be locally adapted and standing genetic variation may not be of long standing.
MicroRNA-190b Targets RFWD3 in ER Positive Breast Cancer
Authors: Frick Elisabet Alexandra , Kristjansdottir Karen , Ragnarsdóttir Snædís , Vilhjalmsson Arnar Ingi , Bustos Maria Rose , Vidarsdottir Linda , Gudjonsson Thorkell , Sigurdsson Stefan
Published: March 2022

Background: In the year 2020 breast cancer was the most common form of cancer. Roughly 70% of breast cancers are estrogen receptor positive. MicroRNA-190b has previously been reported to be up-regulated in estrogen receptor positive breast cancers. Our group has previously demonstrated that microRNA-190b is hypomethylated in ER+ breast cancers, potentially leading to its upregulation. Results: In this study, using data from the Cancer Genome Atlas, we confirm that microRNA-190b is overexpressed in breast cancer via differential expression analysis and show that high expression of microRNA-190b results in more favorable outcomes in Luminal A patients (HR=0.29, 95% CI 0.12-0.71, P value=0.0063). MicroRNA190b target analysis, using immunoprecipitation of biotin labelled microRNA-190b, followed by RNA sequencing, identified RFWD3 as one of microRNA-190b’s regulatory targets in estrogen receptor positive breast cancer. Survival analysis of RFWD3 showed that elevated levels result in poorer overall survival in Luminal A breast cancer patients (HR = 2.22, 95% CI 1.33-3.71, P = 0.002). Gene ontology analysis of our sequencing results indicate that miR-190b may have a role in breast cancer development and/or tumorigenesis and that it may be a suitable tool in characterization between the estrogen receptor positive subtypes, Luminal A and Luminal B.Conclusions: We show that miR-190b targets RFWD3 in ER+ breast cancers leading to lower RFWD3 protein expression. Low levels of RFWD3 are associated with better outcomes in Luminal A breast cancer patients but not in Luminal B patients.
Brain glucose metabolism and gray matter volume in the evaluation of chronic traumatic encephalopathy in retired professional soccer players: a cross-sectional [18F]FDG-PET/MRI study
Authors: Aranha Mateus Rozalem , Coutinho Artur Martins , Carneiro Camila de Godoy , Pastorello Bruno Fraccini , Studart-Neto Adalberto , Guariglia Carla Cristina , Tsunemi Miriam Harumi , Moreira Everton Luis Santos , Ianof Jéssica Natuline , Anghinah Renato , Nitrini Ricardo , Cerri Giovanni Guido , Fortea Juan , Buchpiguel Carlos Alberto , Leite Claudia Costa
Published: March 2022

Background: Professional soccer athletes are exposed to repetitive, sport-related head impacts and are at risk of developing chronic traumatic encephalopathy. This study aims to evaluate regional brain glucose metabolism (rBGM) and grey matter (GM) volume in retired soccer players (RSP).Methods: Male RSP and age and sex-matched controls were prospectively enrolled between 2017 and 2019. Participants underwent neurological and neuropsychological evaluations, brain MRI and [18F]FDG-PET in a 3.0-Tesla PET/MRI scanner. Individual visual analysis was performed by a neuroradiologist and a nuclear physician, blinded to the participant's group. [18F]FDG uptake and GM volume were assessed using SPM8 software. According to data type and distribution, groups were compared using appropriate statistical tests available at SPM8 and R. Results: Nineteen RSP (median: 62 years, IQR: 50-64.5) and 20 controls (median: 60 years, IQR: 48-73) were included. RSP performed worse on mini-mental state examination, digit span, clock drawing, phonemic and semantic verbal fluency tests, and had reduced rBGM in the left temporal pole (pFDR=0.008) and the anterior left middle temporal gyrus (pFDR=0.043). GM volume reduction was observed in similar anatomic regions but was less extensive and did not survive correction for multiple comparisons (puncorrected<0.001, pFDR≥0.085). Individual [18F]FDG-PET visual analysis revealed seven RSP with overt hypometabolism in the medial and lateral temporal lobes, frontal lobes, and temporoparietal regions. RSP had a higher prevalence of cavum septum pellucidum and septum pellucidum fenestration on MRI.Conclusion: RSP had reduced rBGM and GM volume in the temporal lobes and septum pellucidum abnormalities, findings possibly related to repetitive head impacts.