bluuebunny/crossref_metadata_2025 huggingface dataset:
Versatile Base Oil that Breaks Drilling Barriers
Authors: Supramaniam Nandakumar , Ezani Farah Shakinah
Published: November 2019

This paper presents the technical development of an operator's drilling base oil produced from their MG3 plant which was evaluated through extensive laboratory studies and field trials prior to commercialization.

The base oil is based on a majority iso-paraffin component which gives an optimum kinematic viscosity, flash point and pour point for drilling applications. In addition, the drilling fluid has minimal aromatic content to fulfil international eco-toxicity standards set by CEFAS and US EPA, 821-R-11-004 Method 1619. The base oil is compatible with various oil/synthetic mud systems and additives with its low viscosity characteristic lesser than 2.4 cSt at 40 deg C which offers excellent drilling performance for Shallow and Deepwater wells. Furthermore, the base oil exhibits high flash point of more than 90 deg C to reduce potential fire hazard while drilling HPHT and ERD wells. At the same time, its superior pour point (as low as -42 deg C) suitable for storing base oil in sub-zero conditions and to be used as deep-water drilling fluid in extremely cold countries like Russia. Its unique high-performance properties provide exceptional temperature stability and optimum rheological properties throughout the extreme temperature profile of a Deepwater or HPHT well, thus resulting in a very low ECD despite drilling with high ROP.

Field trials were carried out to verify the base oil's performance under laboratory conditions. The base oil was tested as base fluid in SBM for both Shallow and Deepwater wells. The Shallow well was drilled vertically in water depth of 105M with a maximum mud weight of 14.6 PPG and bottom hole static temperature of 280 deg F. The Deepwater well was drilled vertically in water depth of 1008 M and subsequently side-tracked to a maximum inclination of 46 degree. Both wells were drilled successfully without any drilling fluid related issues as compared to severe losses experienced with respective offset wells.

A total of approximately 138 oil and gas wells were drilled by the operator utilizing their own base oil till 2018 after completing the technical evaluation in 2014. From the field trials and actual drilled wells, a comprehensive database analysis was developed for future improvisation and broader performance portfolio. The main technical challenge for the operator was to engineer a drilling fluid system with base fluid and chemical additives to obtain minimal ECD for reducing lost circulation risk. The base fluid properties are ideal for Shallow, HPHT, ERD and Deepwater applications whereby the ECD margin for Deepwater and ERD drilling is often narrow as compared to shallow wells. The successful project execution of base oil for drilling represents a significant milestone, elevating the company's base oil progress at par with other global base oil producers.
Application of Statcom Technology for the First Time in Oil & Gas Fields; Challenges and Way Forward – Case Study.
Authors: Ahmed Walid , El Mahmoud Ziad , Al Shawoush Abdulla
Published: November 2019

Electrical utilities are subject to voltage sags, poor power factor and even voltage instability as long as it suffers from shortage of its reactive power sources. The only mitigation to this problem is to have proper and fast acting reactive power control on the grid. This in turn will overcome the major concerns of network voltage instability, especially during the transient and sub-transients conditions such as major switching operation, and electrical faults.

In many cases, the traditional solutions of switching capacitors is too coarse and slow to stabilize a weak network.

The most advanced solution to compensate reactive power is to incorporate a STATCOM (or Static Synchronous Compensator) as a variable source of reactive power. STATCOM is an advanced power electronic system for fast capacitive/inductive reactive power supply providing reactive power compensation and, steady state and transient voltage stability, etc… These systems offer advantages compared to standard reactive power compensation solutions in demanding applications.

In order to mitigate utility network power quality problems, ADNOC Gas Processing has recently introduced a STATCOM solution in two running plants. This paper deals with the design process of customized Power Quality solutions involving STATCOM Technology to resolve network quality issue up to full commissioning of the system, elaborate on challenges and difficulties faced, and highlight how it was resolved.
Ejector Technology for Flare Gas Recovery as an Alternative to Rotating Equipment
Authors: Ainge Peter
Published: November 2019

A reliable flare system is an important part of most oil and gas facilities. In an emergency or similar process shutdown event where pressure relief is required, the flare system must safely and reliably handle and dispose of waste gas through burning it to atmosphere. However, outside of these emergency cases, many facilities also carry out continuous or routine flaring, where purge gas, waste gas and other low-pressure gasses are sent to flare to be burned to atmosphere.

As the environmental and subsequent legislative pressures have increased over recent years, Operators are actively looking for low cost, reliable Flare Gas Recovery (FGR) solutions. This involves recovering flare gas and diverting it away from the flare system to an alternative destination, thereby avoiding the need to burn the gas to atmosphere. Most commonly, recovered flare gas can be used as fuel gas or returned to production, providing some commercial value to the Operator.

As most flare systems operate at low pressures (close to atmospheric pressure), gas compression is required to increase the gas pressure to allow the recovered flare gas to be used as a fuel gas or returned to production.

Traditionally, rotating-type compression equipment has been employed to compress low pressure flare gas including Liquid-ring, Screw, Sliding Vane or Reciprocating-type compressors.

However, due to their reliance upon moving parts in direct contact with flare gas, rotating equipment is prone to break-down. For many facilities with an FGR system, one of the most common causes of unplanned flaring is due to the breaking-down or ‘tripping’ of FGR compression equipment, counter to its very purpose to reduce flaring. These compression devices are also adversely affected by the flare gas stream, which is often poor quality. As an example, high levels of hydrogen sulphide (H2S) is a very common characteristic for flare gas streams. This ‘sour’ gas is one of the primary causes of degradation of compression equipment. In particular, this affects the equipment seals and sealing arrangements.

This paper explores how Ejector technology (sometimes known as Eductors, Jet Compressors or Surface Jet Pumps) can be used as an alternative to rotating-type compression equipment for FGR and how the unique challenges of this duty are overcome.
Critical Offshore Pre-Engineering Survey Guidelines for Early Jackets
Authors: Athmaram Jayaprakash , Al Sayari Abdul Hakeem , Srinivasan Ashish GS
Published: November 2019

Presently, lower costs, tighter schedules and optimized resources drives project management teams for early production schemes which is becoming a norm among large E&P companies particularly with NOC’s. The challenging market environment has made it desirable to depart from our usual conventional platforms to early production schemes. Due to demanding schedule and urgency to achieve early production targets, sometimes the teams overlook certain critical pre-engineering survey requirements which has the potential to make or break the project.

The criteria used to determine the jacket location for such urgent projects purely depends on the main condition of reachability of the proposed wells to the reservoir and not broadly based on a broad qualitative assessment. It is to be noted that irrespective of its size, early jackets still require detailed assessment of the proposed site and it has to be established beyond doubt that the site is free from subsea interference and seabed debris. An equally important factor to be addressed is the environmental concerns regarding the proposed site. This paper identifies the various factors that influence surveys related to engineering studies for early jackets.

This paper provides a critical offshore survey essentials checklist including sequencing of survey works in order to get maximum value for the Project Management Team that is necessary to be acquired during pre-engineering survey such that seabed surface, subsurface, environmental aspects and surface constraints are duly considered before arriving at the best optimal location for early jacket/s. The proposed guidelines also includes the prospect of expansion opportunities as part of future field development and will help to alleviate the need for any revisit to the site for survey, which would otherwise incur additional costs and cascading delays in the schedule for early production.

The critical survey guidelines here will cover in detail the requirements of acquiring geophysical, geotechnical, meteorological, oceanographic and environmental aspects including parameters that are required to be included in desktop studies about the site.

It is also essential to know the potential rig that is intended to be deployed at the location of interest such that number of rig approach boreholes can be determined based on the orientation of the tower and the planned rig. The geotechnical boreholes are a significant input to specialist studies such as Leg Penetration Analysis (LPA) and/or Site Specific Assessments (SSAs) reports as part of marine warranty location approval process.

The offshore survey essentials guidelines and sequence of survey works provided in this paper may be used as a ready reckoner for project engineering teams that are inclined to undertake early offshore jacket installation works.
Comparing Results of Different Tracer Technologies Application in One Well
Authors: Shestakov Dmitry , Galiev Marat , Badrtdinov Ilshat , Khamidullin Vadim , Ovchinnikov Kirill , Malyavko Evgeny
Published: November 2019

The present article highlights a new approach to solving objectives aimed at efficient and rational development of oil and gas fields based on conducted production logging of Kogalymneftegaz TME, LUKOIL-Western Siberia LLC horizontal wells with the application of marker-based technology Quantum PLT.

Well logging technology using markers is based on the application of quantum marker-reporters precisely indicating oil and water inflows. The placement of markers in the well implies two alternative technological solutions – application of marked proppant during MFrac or application of downhole cassettes with markers installed in the lower completion of the horizontal well. The advantages of the technology involve no necessity of well shut-in during downhole operations and the possibility to obtain an unlimited number of analytical data for a long period of time.

Marker-based technologies produced by different manufacturers differ in physical principles of operation, as well as in the methods of markers placement in the well or reservoir. The results of two alternative marker-based systems application in one well are shown in this article. This approach allowed us to compare the results and to evaluate the advantages and disadvantages of these two technologies. The well was completed by MFrac with the possibility of further ports control with the application of coiled tubing service. Each of five well intervals was equipped with two marker cassettes fixed on both sides of the MFrac port. Three months later MFrac with pumping marked proppant was performed on the well.

As a result of the world-first field application of alternative marker-based systems, valuable analytical material was obtained on the quantitative analysis of various markers, the performance of different polymers, the stability of the markers allocation in the formation fluid. The data obtained confirmed the character of the marked proppant pack washing out with the formation fluid in comparison with cassettes with markers.

Moreover, the efficiency of conducted stimulation was evaluated, specific horizontal well inflow profile types were identified, the degree of the reservoir management system impact on the inflow profile was evaluated.

It has been demonstrated, that received analytical data based on horizontal wells production logging enable addressing the issues of field digitalization at a totally new level, including: –visualizing recovery in hydrodynamical models;–control of hydrocarbon recovery, also by improving water flooding efficiency and better management of injection wells;–efficient planning of well intervention and stimulation techniques;–optimization of horizontal sections length and the number of MFrac ports;–adapting the relevant geological and hydrodynamic models considering analytical data related to production logging data, etc.
Efficient Trans-Dimensional Gravity Inversion of Salt Structures Offshore Abu Dhabi
Authors: Noei Emad Ghaleh , Dettmer Jan , Ali Mohammed , Lee Gyoo Ho , Kim Jeong Woo
Published: November 2019

This work investigates nonlinear inversion of gravity data to infer Infracambrian Hormuz salt structures offshore Abu Dhabi, UAE. A Bayesian approach with a trans-dimensional parametrization of the subsurface is applied that does not require regularization, resulting in more objective inversion results. The trans-dimensional parametrizations discretize the subsurface structure including the salt dome by an irregular grid of Voronoi cells. Both the number of cells and the cell coordinates are unknown parameters estimated from gravity data. The density contrast of the salt structures is assumed as known. The solution in Bayesian inversion is given by a large ensemble of parameter sets. Here, the trans-dimensional ensemble is obtained with the reversible-jump Markov chain Monte Carlo (rjMCMC) algorithm. Residual errors are parametrized by a full covariance matrix, which is estimated and updated as part of an iterative inversion scheme. Efficient rjMCMC sampling is achieved with parallel tempering. Inversion of airborne gravity anomalies illustrates well-defined Infracambrian Hormuz salt structures offshore Abu Dhabi, where the irregular grid spatially adapts to the data information and without the need to impose explicit regularization or fixed grids. Uncertainty estimates highlight salt dome extent. This study provides new insight into the existence and shape of oil reservoirs associated with the underlying salt structures.
Reservoir Description Insights from Inter-well Gas Tracer Test
Authors: Al-Qasim Abdulaziz , Kokal Sunil , Hartvig Sven , Huseby Olaf
Published: November 2019

Tracer technology has gained considerable attention recently as an effective tool in the reservoir monitoring and surveillance toolkit, particularly in IOR operations. Gas flow paths within the reservoir can be quite different from liquid (oil and water) flow path. This is primarily due to gravity override, and differences in density and relative permeability between the gas and liquid phases.

Inter-well gas tracer test (IWGTT) is a key monitoring and surveillance tool for any IOR projects. IWGTT should be designed and implemented to track the flow behavior of gas phase. The test generally entails injecting a small amount of unique perflouro-hydrocarbon tracers into the gas phase injectant stream. IWGTT have been conducted on a limited number of fields across the globe, and sample results of some will be presented.

The sampling frequency of the tracers from the producers should be designed carefully to collect the necessary data that will provide insights about the connectivity between the injectors and producers well pairs, gas breakthrough times ("time of flight"), and possible inter-well fluid saturations. Different fit-for-purpose unique tracers can be deployed in the subject injector(s) stream and their elution can be monitored in the corresponding up-dip producer(s).

In addition to reservoir connectivity and break-through times between injector and producer pairs, an IWGTT helps in optimizing WAG operations and production strategies for gas injection projects, improve sweep efficiency and ultimately enhance oil recovery. It can also be used to identify source of inadvertent gas leakage into shallow aquifers or soil gas, and help in the planning and placement of future wells.

This paper reviews the workflow and necessary logistics for the successful deployment of an inter-well gas tracer test. It will provide the best practices for designing, sampling, analyzing and interpretation of a gas tracer deployment. The paper also highlights the benefits of gas tracer data and their usefulness in understanding well interconnectivity and dynamic fluid flow in the reservoir. The results can be used to refine the reservoir simulation model and fine tune its parameters. This effort should lead to better reservoir description and an improved dynamic simulation model. The challenges associated with IWGTT will also be shared.
Uniform Fracture Growth from Horizontal Wells with Multistage Plug-and-Perf: An Application of Engineered Solid Particulate Diverters
Authors: Fragachan Francisco , Omer Mohammed , Huang Jian
Published: November 2019

To stimulate a reservoir efficiently, multistage plug-and-perf completion and fracturing technologies are widely utilized to create multiple hydraulic fractures along a horizontal wellbore. However, excessive field cases and lab tests evidenced that, the simultaneous initiation and propagation of multiple fractures within a stage could compete with each other, cause uneven fluid and proppant partition into each placed cluster. Resulting in low cluster efficiency and non-uniform fracture development. Solid particulate diverters can aid to influence the fluid distribution between open clusters to optimize stimulation efficiency. The objective of this study is to use numerical models to thoroughly investigate the functionality of particulate system in fracturing process and optimize the completion and stimulation strategy under specific downhole conditions.

In this study, both CFD-DEM model and a 3D fracture simulator are employed to model fluid diversion and fracturing process for wells completed with plug-and-perf technique. For a field case study, sensitive analyses were performed to quantify the impact of completion design and pumping strategy on the resulted stimulation efficiency. The overall conductive reservoir volume is predicted to compare the cluster efficiency between different design scenarios. Thereafter, the stimulation efficiency of placed perforation clusters is analyzed and optimized with engineered solid particulate diverters.

For the presented particulate diversion technique, both in-stage and inter-stage fluid diversion are operationally feasible. From our analysis, engineered solid particulate diverters can effectively plug the active perforation clusters and build-up enough pressure to divert fracturing fluid into non-active perforation clusters to create additional fractures. Proper number of diverter pills and adequate pumping schedule can boost the cluster efficiency and eventually increase the conductive reservoir volume.

Through a field case study, the presented geomechanical analyses showed that the diverter design and operational parameters can be customized to enhance cluster efficiency. By adjusting completion design, the usage of particulate diverters can be optimized accordingly to maximize the stimulation efficiency. With the proposed efficient design, all the planned perforation clusters can develop and propagate hydraulic fractures and contribute to the overall production.
Drix USV - Improving Safety and Margins Through Efficient Data Acquisition
Authors: Eudeline Guillaume
Published: November 2019

Objectives/Scope

The scope of the present paper is to show from concept to track record how iXblue maximized its clients financial and HSE results the use of DriX, an innovative yet seasoned Unmanned Surface Vehicle in the field of Survey and Energies industries.

Methods, Procedures, Process

The overall approach was to create an offshore-going USV with data quality and speed of gathering as the two focal points. In order to do that, iXblue designed –A purely hydrodynamic shape with low water resistance and a higher tolerance to sea states–A gondola housing the sensors which provides the sensors with a perfect data gathering environment. I shall explain how iXblue suppressed the aeration effects on the sensors, and deeply dampened the vibrations and the USV radiated noise

I will also show the audience our Launch and Recovery System, a corner stone for realistic Unmanned Operations at sea.

Results, Observations, Conclusions

The results were excellent. I shall show the audience how DriX exceeded expectations on the field by choosing past missions or trials and providing the audience with the results. These missions could be, for instance: Oil and Gas: Subsea Positioning: a Box-in in the Caspian Sea, performed in minutes; Renewable: Seabed Survey off the North Wales Coast in the UK in North Sea conditions, where DriX performed 3 times faster than a traditional asset; Survey: Multiple months survey in the Tonga islands in the Pacific Ocean along with a regular survey vessel; other missions within the Energy environment. The conclusions are that DriX is reliable, versatile and efficient. It has been designed with HSE and financial sense in mind. Almost two years in operations have shown that the goals have been reached, thanks to the guidance of a number of actors within the Energy Community. DriX is today operating daily around the world, and the scope of applications it does increases regularly.

Novel/Additive Information

DriX ecosystem today encompasses number of capabilities that make it a relevant asset to own or rent. During the conference, I shall equally give a heads up on where we are planning to go in the next few months.
Implementation of the FilmArray ME panel in laboratory routine using a simple sample selection strategy for diagnosis of meningitis and encephalitis
Authors: Pfefferle Susanne , Christner Martin , Aepfelbacher Martin , Lütgehetmann Marc , Rohde Holger
Published: November 2019

Background: Infectious meningitis is a serious disease and patient outcome relies on fast and reliable diagnostics. A syndromic panel testing approach like the FilmArray ME can accelerate diagnosis and therefore decrease the time to pathogen specific therapy. Yet, its clinical utility is controversial, mainly because of a remaining uncertainty in correct interpretation of results, limited data on its performance on clinical specimens and its relatively high costs. The aim of this study was to analyze clinical performance of the assay in a real life setting at a tertiary university hospital using a pragmatic and simple sample selection strategy to reduce the overall cost burden. Methods: Over a period of 18 months we received n=4.623 CSF samples (n=2.338 hospitalizations, n=1.601 individuals). FilmArray ME analysis was restricted to CSF-samples with a high pretest probability of infectious meningitis, e.g. conspicuous Gram-stain, samples in which leukocytes and/or bacteria were evident or urgent suspicion of infection was communicated by clinicians. N=171 samples matched to our risk criteria and were subjected to FilmArray ME analysis. Those samples were also analyzed by reference methods: culture only (n=45), PCR only (n=20) or both methods (n=106). Results: 56/171 (32.75 %) were FilmArray ME positive. Bacterial pathogens were detected in 30/56 (53.57 %), viral pathogens were detected in 27/56 (48.21 %) and yeast DNA was detected in 1/56 (1.79 %) of positive samples. Double detection occurred in 2/56 samples. In 52/56 (92.86 %) FilmArray ME positive samples, results could be confirmed by the reference assays (sensitivity=96.30%, specificity =96.58%). Conclusion: The FilmArray ME assay is a fast and reliable diagnostic tool for the management of infectious meningitis and can easily be implemented in routine diagnostic workflows. However, correlation of test results and underlying clinical symptoms requires experienced users and the awareness of potentially false negative or false positive results. Moreover, considering the need for antimicrobial susceptibility testing, the use of molecular tests as a stand-alone diagnostic cannot be recommended.
CRISPR elements provide a new framework for the genealogy of the citrus canker pathogen Xanthomonas citri pv. citri
Authors: Jeong Kwanho , Muñoz-Bodnar Alejandra , Rojas Nathalia Arias , Poulin Lucie , Rodriguez-R Luis Miguel , Gagnevin Lionel , Vernière Christian , Pruvost Olivier , Koebnik Ralf
Published: November 2019

Background: Xanthomonads are an important clade of Gram-negative bacteria infecting a plethora of economically important host plants, including citrus. Knowledge about the pathogen’s diversity and population structure are prerequisite for epidemiological surveillance and efficient disease management. Rapidly evolving genetic loci, such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), are of special interest to develop new molecular typing tools. Results: We analyzed CRISPR loci of 56 Xanthomonas citri pv. citri strains of world-wide origin, a regulated pathogen causing Asiatic citrus canker in several regions of the world. With one exception, 23 unique sequences built up the repertoire of spacers, suggesting that this set of strains originated from a common ancestor that already harbored these 23 spacers. One isolate originating from Pakistan contained a string of 14 additional, probably more recently acquired spacers indicating that this genetic lineage has or had until recently the capacity to acquire new spacers. Comparison of CRISPR arrays with previously obtained molecular typing data, such as amplified fragment length polymorphisms(AFLP), variable-number of tandem-repeats (VNTR) and genome-wide single-nucleotide polymorphisms (SNP), demonstrated that these methods reveal similar evolutionary trajectories. Notably, genome analyses allowed to generate a model for CRISPR array evolution in X. citri pv. citri, which provides a new framework for the genealogy of the citrus canker pathogen. Conclusions: CRISPR-based typing will further improve the accuracy of the genetic identification of X. citri pv. citrioutbreak strains in molecular epidemiology analyses, especially when used concomitantly with another genotyping method.
An artificially simulated outbreak of a respiratory infectious disease
Authors: Guo Zuiyuan , Xu Shuang , Tong Libo , Dai Botao , Liu Yuandong , Dan Xiao
Published: November 2019

Background Outbreaks of respiratory infectious diseases often occur in crowded places. To understand the spreading pattern of an outbreak of a respiratory infectious disease and provide a theoretical basis for targeted implementation of scientific prevention and control, we attempted to establish a stochastic model to simulate an outbreak of a respiratory infectious disease at a military camp. This model fits the general pattern of disease transmission and further enriches theories on the transmission dynamics of infectious diseases.Methods We established an enclosed system of 500 people exposed to adenovirus type 7 (ADV 7) in a military camp. During the infection period, the patients transmitted the virus randomly to susceptible people. The spread of the epidemic under militarized management mode was simulated using a computer model named “the random collision model”, and the effects of factors, such as the basic reproductive number (R0), time of isolation of the patients (TOI), interval between onset and isolation (IOI), and immunization rates (IR), on the developmental trend of the epidemic were quantitatively analysed. Results Once the R0 exceeded 1.5, the median attack rate increased sharply; when R0=3, with a delay in the TOI, the attack rate increased gradually and eventually remained stable. When the IOI exceeded 2.3 days, the median attack rate also increased dramatically. When the IR exceeded 0.5, the median of the attack rate approached zero. The median generation time was 8.26 days, (95% confidence interval [CI]: 7.84-8.69 days). The partial rank correlation coefficients between the attack rate of the epidemic and the R0, TOI, IOI, and IR were 0.61, 0.17, 0.45, and -0.27, respectively. Conclusions The random collision model not only simulates how an epidemic spreads with superior precision but also allows more flexibility in setting the activities of the exposure population and different types of infectious diseases, which is conducive to furthering exploration of the epidemiological characteristics of epidemic outbreaks.
Impact of the Ebola virus disease outbreak (2014-2016) on Tuberculosis Surveillance Activities in Guinea's National Tuberculosis Program: A Time Series Analysis
Authors: Magassouba Aboubacar Sidiki , Diallo Boubacar Djelo , Camara Lansana Mady , Sow Kadiatou , Camara Souleymane , Bah Boubacar , Barry Alpha Oumar , Diallo Thierno Hassane , Aboubacar Camara , Bangoura Adama Marie , Sow Oumou Younoussa
Published: November 2019

Background Tuberculosis (TB) is a major cause of disease and death worldwide. According to World Health Organization (WHO) estimates, Guinea is a country with a high incidence of tuberculosis (TB) and TB / HIV co-infection. In March 2014, the WHO announced the Ebola virus disease (EVD) outbreak in Guinea that caused a health system disruption. Our study aimed to assess the impact of the Ebola virus disease outbreak on the TB surveillance system through the main indicators of TB-related morbidity and mortality. Methods This is a retrospective cohort study comparing TB trends using TB surveillance data from periods before (2011-2013), during (2014-2016) and after (2017-2018) the Ebola virus disease outbreak. A time-series analysis was conducted to investigate the link between the decrease in TB incidence and the Ebola virus disease through cross-correlation. We evaluated the lag observed in the cross-correlation test using the ANCOVA type II delayed variable dependent model. The current status of the surveillance system was compared to that of 2015 during the EVD through the Standards and benchmarks for TB surveillance and vital registration systems established by WHO. Results The reporting rate of TB cases decreased from 120 cases per 100,000 in 2011 to 100 cases per 100,000 in 2014, while the EVD outbreak was at its peak. The cross-correlation test between the time series of incident cases of all forms of TB and Ebola shows a significant lag of -0.4 (40%), which corresponds to the decrease in the incidence of TB cases observed when the EVD was steep in 2014 (p-value=0.024). However, the EVD had no negative impact on patient treatment outcomes (p-value=0.258). Regarding the surveillance system, out of 13 WHO standards and benchmark, five were reached in 2019 compared to three in 2015. Conclusion The EVD outbreak had a severe impact on TB surveillance in Guinea, with a significant decline in TB reporting rates during the epidemic period. The introduction of an early warning system would preserve the TB surveillance system ; which could encourage the implementation of interventions to ensure access to diagnosis, and enhanced surveillance for the treatment of TB.
Mortality Prediction in Pediatric Patients with Sepsis of Abdominal Origin: A Retrospective Study
Authors: Shan Yijun , Shi Jingyi , Sun Ting , Ren Yuqian , Zhu Guangyao , Zhou Yiping , Cui Yun
Published: November 2019

Aims: The aim of this study was to assess the prediction of mortality in pediatric patients with sepsis of abdominal origin.
Methods: We performed a retrospective study of patients with sepsis of abdominal origin admitted to the pediatric intensive care unit (PICU) in Shanghai Children’s Hospital between May 2014 and April 2018.
Results: A total of 143 patients were enrolled in this study. The mortality rate in pediatric patients with sepsis of abdominal origin was 11% (17/143). PRISMIII score, the grade of acute gastrointestinal injury (AGI), hematologic malignancy, acute kidney injury, the initial number of organ dysfunction, alanine aminotransferase (ALT), and blood platelet (PLT) were potential risk factors for increased mortality. Multivariate logistic regression analysis indicated that higher Pediatric risk of mortality III (PRISM III) score and the grade of AGI were independent risk factors of mortality in patients with sepsis of abdominal origin. Furthermore, the area under receiver-operating characteristic (ROC) curve (AUC) for PRISM III score and the grade of AGI were 0.91 (95% confidence interval (CI) 0.86–0.96, P<0.001) and 0.83 (95% CI 0.74–0.92, P<0.001), in which the optimal cut-off value was 10.5 and 2.5, respectively. In addition, the Kaplan-Meier curve indicated that the 28-day survival rate was significantly lower in patients with higher PRISM III score (>10.5) and the grade of AGI (>2.5).
Conclusions: Higher PRISM III score and the grade of AGI were associated with poor outcomes in pediatric patients with sepsis of abdominal origin.
The importance of strengthening public health systems based on primary health care in designing a successful vaccination strategy: an example of qualitative research in three regions of Senegal.
Authors: Bianchi Jacopo , Milani Chiara , Bechini Angela , Boccalini Sara , Pinilla Maria José Caldes , Bonaccorsi Guglielmo , Bonanni Paolo
Published: November 2019

Background
Because of its low cost and its capability in reducing child mortality and morbidity, vaccination is considered a successful preventive deed in Low and Middle-Income Countries. In Senegal, vaccines are provided free of charge by the public health system, but the provision of the service is not evenly distributed between and within the Regions. Our study aimed at identifying barriers and enabling factors towards vaccination in three Regions of Senegal.
Methods
We performed 41 face-to-face semi-structured interviews with health services’ workers and three focus groups with local women in nine different structures in three different Regions of Senegal. We combined health workers’ (HW) and mothers’ points of view with direct observation in order to fulfill our purpose.
Results
We identified three groups of barriers – structural, personal and psychological – and many subthemes for each of them. Structural and personal barriers such as inadequacy of health structures, shortage of HW, lack of money, distance between villages and health facilities and lack of public transport, hamper mothers from utilising the vaccination service, even when they want to. The lack of effective communication between health personnel and mothers, the lack of collaboration between traditional and conventional medicine and the lack of trust in the public health system as a whole, are major problems to the vaccination uptake too.
Conclusions
The interlink of several elements in conditioning vaccination coverage suggests the need of implementing global and national strategies to overcome them. The key factor is the presence of a solid health system, publicly funded, based on primary health care. On the other hand, context-specific determinants cannot be detected based on global and non-specific information. The role of community health workers (CHWs) is crucial in overcoming wrong beliefs, lack of knowledge and distrust. They must be regarded as a bridge between HW and population. CHWs should be formally included in the organization of the social-health system, adequately formed and enhanced.
Access to primary healthcare services and associated factors in urban slums in Nairobi-Kenya
Authors: Otieno Peter O. , Wambiya Elvis Omondi Achach , Mohamed Shukri M , Mutua Martin Kavao , Kibe Peter M , Mwangi Bonventure , Donfouet Hermann Pythagore Pierre
Published: November 2019

Background: Access to primary healthcare is crucial for the delivery of Kenya’s universal health coverage policy. However, disparities in healthcare have proved to be the biggest challenge for implementing primary care in poor-urban resource settings. In this study, we assessed the level of access to primary healthcare services and associated factors in urban slums in Nairobi-Kenya. Methods: The data were drawn from the Lown scholars’ study of 300 randomly selected households in Viwandani slums (Nairobi, Kenya), between June and July 2018. Access to primary care was measured using Penchansky and Thomas’ model. Access index was constructed using principal component analysis and recoded into tertiles with categories labeled as poor, moderate and highest. Generalized ordinal logistic regression analysis was used to determine the factors associated with access to primary care. The adjusted odds ratios and 95 percent confident intervals were used to interpret the strength of associations. Results : The odds of being in the lowest versus combined moderate and highest access tertile were significantly higher for female than male-headed households (AOR 1.91 [95% CI 1.03-3.54]; p < .05). Households with an average quarterly out-of-pocket healthcare expenditure of ≥$30 had significantly lower odds of being in the lowest versus combined moderate and highest access tertile compared to those spending ≤ $5 quarterly (AOR 0.33 [95% CI 0.50-1.90]; p< .001). Households that sought care from private facilities had significantly higher odds of being in the lowest versus combined moderate and highest access compared to the public facilities (AOR 3.77 [95% CI 2.16-6.56]; p < .05). Conclusion : In Nairobi slums in Kenya, the gender of the household head, out of pocket healthcare expenditure, and source of primary care are significantly associated with access to primary care. Therefore, the universal health coverage program in this setting should be designed with an equity lens so that the most vulnerable groups within the community can have access.
One-year clinical and angiographic outcomes after percutaneous coronary interventions in ostial versus distal left main lesions – a retrospective single center study
Authors: Stephan Tilman , Goldberger Nadine , Keßler Mirjam , Felbel Dominik , Rattka Manuel , Wöhrle Jochen , Rottbauer Wolfgang , Markovic Sinisa
Published: November 2019

Background: Percutaneous coronary intervention (PCI) of left main coronary artery disease (LMD) is associated with appropriate clinical and angiographic outcomes, resulting in a class I recommendation in patients with less complex coronary anatomy. Due to higher SYNTAX scores and worse clinical outcomes, PCI in distal LMD is accomplished with a lower strength of recommendations for revascularization compared to ostial LM lesions. We compare angiographic and clinical outcomes of ostial/midshaft lesions versus distal lesion in LMD after PCI.
Methods: This retrospective study included 176 patients with LMD undergoing PCI with drug-eluting stents. The study population was divided into 34 patients with ostial/midshaft LMD and 142 patients with distal LMD. Patients were routinely scheduled for 9 months of angiographic and 12 months of clinical follow-up. Quantitative coronary analysis (QCA) was performed for all lesions, using an 11-segment model. Primary outcome was MACE (major adverse cardiac events) defined as a composite of cardiac death, myocardial infarction and target lesion revascularization (TLR).
Results: The primary outcome measure was comparable in both cohorts after 12 months follow-up (20.6% in ostial/midshaft LMD vs. 17.6% in distal LMD, P=0.71). As expected, TLR rates were increased in distal LM lesions compared to ostial LM lesions, but without reaching statistical significance (14.1% vs. 5.9%, P=0.15). Late lumen loss (LLL) in ostial/midshaft LMD was 0.42±0.33mm. In distal LM lesions value for LLL in the main vessel was 0.42±0.97 mm, with the highest values observed in segments adjacent to the bifurcation (0.37±1.13mm and 0.37±0.73 mm). On cox proportional regression analysis LLL in a bifurcation segment (P=0.03, HR 1.68 [1.1-2.7]) and diabetes mellitus (P=0.046, HR 2.77 [1.0-7.5] were independent correlates for occurrence of MACE.
Conclusion: PCI of distal LM lesions result in comparable angiographic and clinical outcomes compared to ostial LM lesions. Highest rates for binary restenosis were observed in segments nearest to the bifurcation.
If the weak were strong and the strong were weak
Authors: Lohitsiri Nakarin , Tong David
Published: November 2019

We explore the phase structure of the Standard Model as the relative
strengths of the SU(2)SU(2)
weak force and SU(3)SU(3)
strong force are varied. With a single generation of fermions, the
structure of chiral symmetry breaking suggests that there is no phase
transition as we interpolate between the SU(3)SU(3)-confining
phase and the SU(2)SU(2)-confining
phase. Remarkably, the massless left-handed neutrino, familiar in our
world, morphs smoothly into a massless right-handed down-quark. With
multiple generations, a similar metamorphosis occurs, but now proceeding
via a phase transition. In the second half of the paper we introduce a
two-parameter extension of the Standard Model, a chiral gauge theory
with gauge group U(1)\times Sp(r)\times SU(N)U(1)×Sp(r)×SU(N).
We again explore the phase structure of the theory as the relative
strengths of the Sp(r)Sp(r)
and SU(N)SU(N)
gauge couplings vary.
EWOLUCJA PRAWNEGO STATUSU ORGANÓW NADZORUJĄCYCH BEZPIECZEŃSTWO WYKORZYSTYWANIA ENERGII JĄDROWEJ W POLSCE
Authors: Nowacki Tomasz R.
Published: November 2019

Do połowy XX w. z braku wyspecjalizowanych organów państwowych i przepisów prawa użytkownicy źródeł promieniowania bazowali na własnej wiedzy praktycznej i teoretycznej w zakresie wpływu promieniowania na organizm ludzki i możliwości ochrony przed jego negatywnymi skutkami. W latach pięćdziesiątych XX w. powstały pierwsze wprost poświęcone ochronie przed promieniowaniem przepisy rangi państwowej, a w dekadę później wyznaczono organ odpowiedzialny za regulację działalności z wykorzystaniem źródeł promieniowania jonizującego. Przez kolejne dekady organ ten zmieniał nazwę i usytuowanie w strukturze instytucji państwowych, łącząc kompetencje nadzorcze w zakresie bezpieczeństwa ze swoim pierwotnym i głównym zadaniem w postaci stymulacji i koordynacji rozwoju wykorzystania energii jądrowej i technik jądrowych w Polsce. Stopniowo pod wpływem międzynarodowych trendów i prawodawstwa wykształcał się organ odpowiedzialny wyłącznie za bezpieczeństwo jądrowe, ochronę radiologiczną, ochronę fizyczną obiektów i materiałów jądrowych oraz zabezpieczenia materiałów jądrowych. Aktualnie organem tym jest Prezes Państwowej Agencji Atomistyki będący naczelnym organem dozoru jądrowego i jednocześnie centralnym organem administracji rządowej.
Recent Advances in the Chemistry and Synthesis of Thienopyrazine, Pyrrolopyrazine and Furopyrazine Derivatives
Authors: Heravi Majid M. , Feiz Afsaneh , Bazgir Ayoob
Published: November 2019

Bicyclic compounds derived from pyrazine and aromatic five-membered heterocycles including thiophene, furan and pyrrole show various biological and pharmacological proBicyclic compounds derived from pyrazine and aromatic five-membered heterocycles including thiophene, furan and pyrrole show various biological and pharmacological properties, such as anti-inflammatory, antiviral, antitumor, antioxidant, antimycobacterial, and cytostatic activities. In many cases, it has been demonstrated that there are more potent cytostatic and cytotoxic agents against human tumor cell lines, leukemia, colon cancer, central nervous system cancer, melanoma, ovarian cancer, prostate cancer and breast cancer. They are also useful precursors for the large scale preparation of inorganicorganic hybrid solar cells, suitable acceptors for the synthesis of low-band gap polymers. They use ligands for serotoninergic 5-HT7 receptor and are effective in neurogical and psychiatric diseases, antimalarial, neuroleptic and cardiovascular. The absence of any useful review concerning the chemistry and synthesis of the above-mentioned heterocyles encouraged us to underscore the recent advances in chemistry and synthetic approaches leading to the preparation of thienopyrazines, pyrrolopyrazines and furopyrazines since 1990.perties such as anti-inflammatory, antiviral, antitumor, antioxidant, antimycobacterial, and cytostatic activities. In many cases, it has been demonstrated that they are much more potent cytostatic and cytotoxic agents against human tumor cell lines, leukemia, colon cancer, central nervous system cancer, melanoma, ovarian cancer, prostate cancer and breast cancer. They also are useful precursors for the large scale preparation of inorganic-organic hybrid solar cells, suitable acceptors for the synthesis of low-band gap polymers. They use as ligands for serotoninergic 5-HT7 receptor and being effective in neurogical and psychiatric diseases, antimalarial, neuroleptic and cardiovascular. Due to the absence of any useful review concerning the chemistry and synthesis of the above-mentioned heterocyles encouraged us to underscore the recent advances in the chemistry and synthetic approaches leading to preparation of thienopyrazines, pyrrolopyrazines and furopyrazines from 1990 up to date.
Regioselective Synthesis of Diverse Thio-, Seleno-substituted 1,2,3-Triazoles
Authors: Zhang Lin-Lin , Wu Qin-Pei , Xu Zhi-Bin
Published: November 2019

:

Thio-, seleno-substituted triazoles are useful scaffolds employed in the fields of
organic synthesis, medicinal chemistry, and material science. A number of synthetic approaches
to efficient formation of thio- and seleno-triazoles have been disclosed, including
the interception of copper(I) triazolides generated in-situ, cycloaddition of internal alkynes
(thio-, halo-, and metalated alkynes) to azides, and the coupling of azides and nonalkyne
substrates. This mini-review intends to summarize the synthetic methods toward
thio-, seleno-1,2,3-triazoles and the relative reaction mechanisms.
Gingiva-derived Mesenchymal Stem Cells and Their Potential Applications in Oral and Maxillofacial Diseases
Authors: Cao Zhengguo , Gao Xudong
Published: November 2019

Background:

Stem cells are undifferentiated cells with multilineage differentiation potential.
They can be collected from bone marrow, fat, amniotic fluid, and teeth. Stem cell-based therapies
have been widely used to treat multiple diseases, such as cardiac disease, and hematological disorders.
The cells may also be beneficial for controlling the disease course and promoting tissue regeneration in
oral and maxillofacial diseases. Oral-derived gingival mesenchymal stem cells are easy to access and
the donor sites heal rapidly without a scar. Such characteristics demonstrate the beneficial role of
GMSCs in oral and maxillofacial diseases.

Objective:

We summarize the features of GMSCs, including their self-renewal, multipotent differentiation,
immunomodulation, and anti-inflammation properties. We also discuss their applications in oral
and maxillofacial disease treatment and tissue regeneration.

Conclusion:

GMSCs are easily harvestable adult stem cells with outstanding proliferation, differentiation,
and immunomodulation characteristics. A growing body of evidence indicates that GMSCs have
strong potential use in accelerating wound healing and promoting the regeneration of bone defects,
periodontium, oral neoplasms, salivary glands, peri-implantitis, and nerves. Moreover, alginate, polylactic
acid and polycaprolactone can be used as biodegradable scaffolds for GMSC encapsulation.
Various growth factors can be applied to the corresponding scaffolds to obtain the desired GMSC differentiation
and phenotypes. Three-dimensional spheroid culture systems could optimize GMSC properties
and improve the performance of the cells in tissue engineering. The immunomodulatory property
of GMSCs in controlling oral and maxillofacial inflammation needs further research.