bluuebunny/crossref_metadata_2025 huggingface dataset:
Sparse Representation of 4D Seismic Signal Based on Dictionary Learning
Authors: Soares Ricardo Vasconcellos , Luo Xiaodong , Evensen Geir
Published: May 2019

This work presents the use of Dictionary Learning methods for a sparse representation of 4D seismic data in history matching. We consider a trade-off between the number of coefficients retained in the sparse data representation, the computational cost, and how well we can capture the main features of the 4D seismic signal. K-SVD is an iterative algorithm used in Dictionary Learning problems that alternates between the calculation of the sparse representation vector and dictionary update. For the definition of the sparse representation vector, one can constrain the problem into two distinct approaches: (1) sparsity-constrained; and (2) error-constrained. We evaluated the two methods and the influence of critical parameters of the algorithm (dictionary size, number of iterations, patch size, and training dataset size) using a synthetic reservoir model. Results showed that regardless of which of the constrained approaches we used, the dictionary learning method can capture the main features of the 4D seismic signal with a sparse representation. However, the number of nonzero coefficients is highly dependent on the approach. Besides, dictionary size, number of iterations, patch size, and training dataset size, also have a significant impact on the number of coefficients and the computational cost. Consequently, the selection of these variables is crucial as it might affect the history-matching process. In a permanent-reservoir-monitoring (big data) scenario, the use of sparse representation allows us to retain the main features of the reservoir in a reasonably sized data representation that can be directly used in a history matching method, leading to improved reservoir characterization and a better understanding of the reservoir properties. This paper gives a practical implementation of a technique already used in other areas (image denoising, processing of raw seismic data, and facies representation) applied to 4D seismic data.
Adsorption of Crude Oil Polar Components onto Silica-Rich Chalk and its Impact on Wetting
Authors: Klewiah Isaac , Piñerez Torrijos Iván Darío , Strand Skule , Puntervold Tina , Konstantinopoulos Miltiadis
Published: May 2019

Adsorption of polar crude oil components exert a major impact on chalk wetting, and adsorption effects have been reported on water-wet pure Stevns Klint outcrop chalk (>99% CaCO3). Aalborg chalk is a silica-rich material also used as analogue rock material for chalk reservoir studies. This work aims to characterize the impact silica minerals will have on polar crude oil component adsorption, and core wettability.

Silica-rich (6-8 At %) Aalborg chalk cores with initial water saturation (Swi) of 10% were flooded with a crude oil with acid and base numbers (AN and BN) equal to 0.35 mg KOH/g of oil. Effluent crude oil samples were analyzed, detecting changes in the AN and BN concentrations at the core outlet. Wettability was determined by spontaneous imbibition (SI), and further confirmed by chromatographic wettability tests.

Adsorption of polar crude oil components was observed to be an instantaneous process. The adsorption of polar acidic components onto the Aalborg chalk surfaces was less profound as previously observed in Stevns Klint chalk. However, adsorption of polar basic components was significantly higher in Aalborg chalk, which could be explained by the presence of negatively charged silicate surfaces. The water wetness of the Aalborg Chalk core was significantly reduced after the crude oil exposure.

This comparative study on both Aalborg and Stevns Klint chalk highlights the impact of silica content on adsorption of polar components and initial wetting. The findings contribute with essential information for the development of theoretical and chemical models to describe initial reservoir wetting and explain oil production profiles in chalk reservoirs during normal water injections, or during wettability alteration with Smart Water.
Understanding Loss Mechanisms – The Key to Successful Drilling in Depleted Reservoirs?
Authors: Scheldt Therese , Andrews Jamie Stuart , Lavrov Alexandre
Published: May 2019

An important measure for increasing oil and gas recovery is infill drilling. For mature fields, drilling and completion of new wells can be challenging due to a limited (or non-existent) operational window. The operational window is defined by an upper and a lower bound. The lower bound is usually based either on the pore pressure or the borehole stability limit, whichever is higher. The upper bound is an estimate of the maximum hydraulic pressure the wellbore wall can be exposed to without experiencing fluid loss (called Fracture Gradient, FG). Losses can occur in all types of reservoirs, but depleted reservoirs are more prone to losses because of reduced pore pressure and the decreasing in-situ stress. With reducing stress, the fracture propagation pressure decreases, and it becomes easier to open and drive a hydraulic fracture. A mitigating factor is to reduce mud weight, but this is not always possible in cases of differential depletion where there can be a complex distribution of pore pressure and fracturing pressure along the well. In many such cases, a FG much larger than the fracture propagation pressures in the low-pressure zones is required so that a mud weight can be selected that will balance the high-pressure zones. Such strategies then rely on the extra "strength" provided by the wellbore and specialized particles. Lost-circulation issues lead to non-productive rig time and direct costs associated with lost volumes of mud. If not managed correctly, they may also lead to loss of well/technical sidetrack and, in the worst case, serious well control incidents. Understanding the mechanisms in play is crucial for curing losses, since lost circulation materials used to treat losses caused by induced fractures are not necessarily effective against losses in naturally fractured rocks because of differences in fracture aperture and connectivity. Numerical modelling and analysis of lost-circulation mechanisms are presented in this article. Losses at so-called weak points are addressed and analysis of field data is discussed. Different potential influences on the FG are considered. Effects of varying rock properties and reservoir depletion, and different borehole geometries are modelled and discussed. Shale/sand interfaces are modelled as potential weak-zones and the resulting shear stresses across such interfaces are analyzed during drill-out. We find that such interfaces can be potential weak-zones and that boreholes with non-circular shape are more likely to experience tensile fracturing and mud losses. This highlights the challenges when estimating FG for heavily depleted reservoirs and it confirms the understanding that poor drilling practice which can create weak-points can directly reduce the FG (in addition to unfavorable ECD conditions in well).
World First Simultaneous Jetting of 72 Laterals with Solids Control - Technology Development and Field Trial
Authors: Bjørnseth Fabian , Kristiansen Tron Golder , Flatebø Roar , Reinertsen Trond , Caline Yann , Østensen Ragnhild , Tomczak Daniel , Solhaug Kristian , Leinenbach Maximilian , Jørgensen Thomas
Published: May 2019

This paper presents the development and installation of a modified stimulation system, based on an existing system, field-proven for more competent formations. The system simultaneously deploys 0.8 cm diameter, 12 m long needles from the main bore by jetting into the formation. Modifications have been made to facilitate production from a soft chalk formation, which is prone to plastic deformation and liquefaction under the stresses of production. The original design of single titanium needles has been changed to a combination of an aluminum outer needle for the deployment phase, and a titanium slotted inner needle for the production phase. The aluminum needle is dissolved by pumping hydrochloric acid, enabling production through the inner needle.

The objective of the system is to reduce cost by simplifying the stimulation to a single pumping job, while achieving production enhancement for wells drilled in pay zones of less than 25-meter thickness. The objective of the field trial was to confirm the system could be deployed offshore, and to evaluate its production performance.

A series of functional tests to ensure pressure integrity of the modified design were performed in the lab. Promising lab test results were extended to functional yard trials, to verify the chance of success at downhole-like conditions. The running procedure was modified to honor well control requirements, while optimizing the likelihood of successful deployment of the system.

The paper presents the results of the qualification testing. The experiences from the installation and jetting are discussed in detail. Interpreted pumping pressure charts are presented for discussion. The productivity results are presented and compared to conventionally stimulated Valhall producer wells.

The installation of the jetted needles system with solids-control slotted laterals is the first of its kind in the world. The results of lab and yard testing presents a solution for achieving solids control in laterals jetted out from the main bore. Analysis of the deployment data provides grounds for future optimization of the system. The productivity results are used to evaluate whether the system is ready for full scale deployment across an entire horizontal well.
Practical Method to Benefit from the Improved Accuracy of Combining Overlapping Wellbore Surveys
Authors: Bang Jon , Ali Tarig , Ledroz Adrián
Published: May 2019

Weighted averaging of overlapping surveys will improve the estimate of the wellbore position and reduce the position uncertainty. An existing, rigorous method describes how the optimal weight factors can be achieved. However, the rigorous method is not commonly used, because of the complexity of the data management and processing.

We have developed a procedure for creating a combined instrument performance model (IPM) file that directly yields the reduced uncertainty of the averaged surveys, when it is applied as input to standard position error analysis. This represents an important step towards simplification of the rigorous procedure. Comprising inclination- and azimuth-dependent weight factors, one such file may be valid for any wellbore profile at any direction, and over an entire oil field. This is demonstrated in the paper for various synthetic well profiles, through comparison with results obtained by the rigorous averaging procedure.

The combined IPM file facilitates the simultaneous use of all available survey information in a consistent way. This may yield significant improvements to the wellbore position accuracy. Furthermore, the new procedure may help in the construction of instrument performance models for new survey tools that incorporate fixed combinations of sensor packages, which may result from recent years’ development of solid state sensors.
Disruptive Clamp-On Technology Tested for Mud Measurement
Authors: Olsvik Kenneth , Hansen Jondahl Morten , Toftevåg Kjell Rune , Kippersund Remi , Elseth Geir , Kjøsnes Ivar
Published: May 2019

During drilling operations, it is of vital importance to have accurate and reliable volume control, with as fast as possible detection of flow abnormalities. The earlier a flow abnormality is detected; the faster actions can be taken to minimize the consequence and cost of a potential well control incident. Accurate and reliable measurements of the inflow of mud and return flow is key to improvements in volume control and early kick detection. Uncertainty and time delay in these measurements may lead to well control incidents such as uncontrolled fracturing, collapse of wells, influx and, in worst case, external spill of oil and gas to the surface.

Existing inline traditional meters experience challenges due to clogging of measurement ports, mechanical erosion or damages on gaskets. Such being caused by the nature of mud consisting of a mixture of heavy materials and cuttings from the formation. Most of them are also not able to give quantified measurements, relying on human interpretation of trends in the data.

Using Clamp-on flow meters for mud measurement would significantly reduce cost, risk and maintenance work if it could generate accurate and reliable measurements. However, due to its nature, drilling mud is a difficult medium to measure and several other technologies have come short trying to do so, including previous ultrasonic measurement techniques.  

This non-invasive ultrasound transmission concept, enables off-center beam transmission, forming the functionality of a multi-beam inline acoustic flow meter. The patented technology achieves this through disruptive acoustic guided wave transmission technology where the pipe wall is used as an advanced transmitting gateway between sensors, and helical shaped transducers enables measurements off-center signal transmission creating shorter paths than traditional clamp-on Meters in addition to traditional axial signal transmission. Combining these features enables measurements also through mud.

This paper will present the theory behind the technology, technology advantages and potential, as well as flow test results from mud flow loop at a Mud loop testing facility in Norway performed in September 2018 where the Meter was subjected to detecting incremental changes in flow rate of mud at different flow rates.
Digital Well Planning, Well Construction and Life Cycle Well Integrity: The Role of Digital Experience
Authors: Brechan Bjorn , Sangesland Sigbjorn
Published: May 2019

Automation is about to bring major changes to the work process for well planning. The next generation well planning tools will take the steps to higher levels of automation, which can provide step changes in quality of the planning, safety aspects in operations and reduce time and cost for planning and operations.

This article discusses the changes that will follow a new standard in well planning and operations. Analysis of the current practices and investigating the potential of a fully automated planning tool leads to a complete re-structuring of the work process. Well planning is a multidisciplinary activity where representatives from the different subsurface disciplines collaborates with the wells engineers in a compromise-prone process often with multiple iterations due to the differences in objective and understanding. The arrival of cross discipline 3D visualization tools has led to improvements in average duration of planning, but it is still a process depending on the efforts of the participating individuals and their level of experience. In an era where computers are landing passenger planes and the pilot has a verification role, it is time to look at the potential in digitalization for well planning and operations.

Many software developers are familiar with the difficulty in developing a "solution" to a challenge in a complex environment such as well construction and production. Many areas of expertise are involved and it is easy to end up with a compartmentalized product which is specialized for one area or a specific challenge. Establishing links and communication to all engineering and calculations in Wells, Subsurface and Production (e.g. well integrity data) are a matter of cost and safety. The next generation well planning tools has to incorporate all areas of expertise from planning well construction, through producing wells to final P&A.

The key enabler for automating the well planning process is the digital experience module, which will be the main task and focus for the Wells Teams. With built in experience, the application has rules and enhanced algorithms allowing Subsurface Teams to make accurate well plans and mature optimal well designs without involving the Wells Teams. Subsurface can identify the optimal drainage and well path including anti-collision, future side tracks, regulations in governing documentation and follow "local best practice". The Wells teams are ultimately responsible and will verify the well path generated by the software, and do any required updates.
Reconstruction of Pipe Movement from Downhole High Frequency Measurements
Authors: Cayeux Eric , Seim Per , Solvi Lars Jørgen , Ulvik Håvard , Solbu Espen
Published: May 2019

The lateral movement of drill-pipes, while rotating, can be the source of diverse drilling problems, such as tool-joint wear, grinding of cuttings into a fine powder that is very hard to transport, formation instabilities. Yet, it is virtually impossible to estimate the sideway displacements of drill-pipes as soon as the distance is greater than a couple of stands from a measurement source, like a dynamic sub placed in the bottom hole assembly (BHA).

It is therefore tempting to place dynamic subs along the drill-string with the objective of detecting any pipe movements that could have a negative impact on the drilling operation. However, to be useful, the measurements must be made at a relatively high frequency, in practice above 80Hz, and with enough precision. For that reason, we have placed a dynamic sub that measures axial and tangential accelerations, rotational velocity, 2-axis bending moment, torque and tension, approximatively 300m behind the bit while drilling two 9 ½-in lateral sections of a horizontal multilateral well.

The dynamic sub sent rotational speed, torque and tension at 80Hz through wired-pipe telemetry and burst data for all the measurement channels were recorded in memory, for 10s at 800Hz every 15 minutes. We have been able to test a method to collect and interpret the high-speed telemetry data, i.e. 80Hz, and we have post-analyzed the burst memory data. A methodology has been developed to compensate systematic errors on the accelerometer sensors by taking advantage of the redundancy of the measurements present in the mechanical-sub. An interpretation software has been used to reconstruct the likely 3-dimensional pipe movement at the location of the measurement tool. The analysis has shown a surprisingly large variation of pipe movement patterns and astonishing fast changing levels of lateral movement throughout the two runs where the tool has been used.

With such a pipe reconstruction methodology at hand, it can be envisaged to perform the processing downhole, i.e. directly into the dynamic sub, and to transmit information about the 3-dimensional movement of the pipe. Such information would be valuable, when received in real-time from distributed sensors, to inform the drilling operational team about possible detrimental drill-pipe vibrations that are not necessarily associated with abnormally high accelerations.
Dissolvable Technology Enhances Operational Efficiency of Offshore Completion Operations on the NCS
Authors: Keerthivasan Vijay Kumar , Koløy Tom Rune
Published: May 2019

In a typical well completion system, retrievable plugs run on wireline are used to set production packers and thereafter, to perform leak testing of the upper completion tubing. There are significant costs and risks associated with these intervention operations to set and retrieve aforementioned plugs. This paper presents the development and implementation of a system using dissolvable technology that allows for interventionless packer-setting and tubing testing of upper completions. The solution developed is a packer-setting kit consisting of a seat profile and a dissolvable ball. The seat is run as part of the tubing string below the production packer. After landing the completion string, the dissolvable ball is dropped from surface to land on the seat profile below the packer. This ball-seat system holds pressure from above, thereby, enabling the production packer to be set and a leak testing of the tubing to be performed. Eventually, the ball dissolves completely in the presence of downhole packer fluids permitting start-up of production activities.

This paper documents the extensive qualification test program which was undertaken to qualify a dissolvable ball-seat system for one-such application. These tests were aimed to verify the capability of the packer-setting kit to fulfil the operational requirements (pressure rating, dissolution time periods) under the specific downhole conditions (packer fluid type, temperature). Following successful qualification testing, this solution was successfully implemented in 3 wells on the Norwegian Continental Shelf in 2018. Adopting this technology significantly improved operational efficiency by reducing well completion and intervention times along with associated costs. Consequently, this enabled earlier production start-up on these wells. The most challenging aspect of this new approach is the selection and qualification of a suitable dissolvable ball material appropriate for the application-specific requirements and operational constraints. The various steps and tests necessary to verify suitability of dissolvable technology for such applications are outlined in this work. Key operational considerations which need to be kept in mind when implementing this solution shall also be addressed.
Stretching Lower Completion Limits: Longest One Screen Run in Horizontal Extended Reach Drilling / Multilateral Well on Troll Field, North Sea
Authors: Qamar Mubashir , Vold Anders
Published: May 2019

The Troll field is in the Norwegian sector of North Sea at water depth 300 – 350 m. The field came on stream in 1995 and developed as subsea field. The field has been Norway's biggest oil producer the past five years. The shut-in wellhead pressure is around 140 bar and static temperature 70°C.

The 6 5/8’’ × 5 ½’’ screens were run in 8 ½ horizontal reservoir section in one run to target depth at 6345 m. The length of screen section was 4300 m. The success of this job is considered as the longest screen run in the company because of excellent teamwork between onshore engineering and offshore teams.

To date, all the wells on Troll field over target depth approx. 6200 m were completed with minimum two screen runs which involves extra tubular management, need for service company personnel & equipment for two screen runs.

The planning of this operation required a thorough design of the landing string to run the screens. This included checking previous experiences on the same rig and field to carefully analyze the torque and drag simulations to understand the buckling & weight limitations. It was crucial to use correct friction factor in the simulations and quality control the input parameters which can impact the available weight & buckling. In addition, the downhole data from tripping out of hole with 8 ½’’ drilling BHA prior to run the screens was also utilized to understand the well condition.
EEG beta-band spectral entropy predicts the effects of drug treatment on patients with herpes zoster
Authors: Wei Mengying , Liao Yuliang , Liu Jia , Li Linling , Huang Gan , Li Disen , Huang Jiabin , Xiao Lizu , Zhang Zhiguo
Published: May 2019

Background

Medication is the main approach for early treatment of herpes zoster (HZ), but it could be ineffective in some patients. It is highly desired to predict the medication responses in order to control the degree of pain for HZ patients. The present study is aimed to elucidate the relationship between medication outcome and neural activity using electroencephalography (EEG) and to establish a machine learning model for early prediction of the medication responses from EEG.

Methods

We acquired and analyzed eye-closed resting-state EEG data 1-2 days after medication from 70 HZ patients with different drug treatment outcomes (measured 5-6 days after medicaiton): 45 medication-sensitive pain (MSP) patients and 25 medication-resistant pain (MRP) patients. EEG power spectral entropy (PSE) of each frequency band was compared at each channel between MSP and MRP patients, and those features showing sigificant difference between two groups were used to predict medication outcome with different machine learning methods.

Results

MSP patients showed significantly weaker beta-band PSE in the central-parietal regions than MRP patients. Based on these EEG PSE features and a k-nearest neighbors (k-NN) classifier, we can predicate the medication outcome with 80% ± 11.7% accuracy, 82.5% ± 14.7% sensitivity, 77.7% ± 27.3% specificity and an AUC of 0.85.

Conclusion

EEG beta-band PSE in the central-parietal region is predictive of the effectiveness of drug treatment on HZ patients, and it could potentially be used for early pain management and therapeutic prognosis.
T2 formula in a highly myopic population, comparison with other methods and description of an improved approach for estimating corneal height
Authors: Idrobo Carlos Alberto , Santaella Gisella , Gutiérrez Ángela María
Published: May 2019

Background: To determine the accuracy of the T2 formula as applied to highly myopic eyes, to compare the T2 formula to the SRK/T and Holladay 1 formulas, and to describe possible ways to improve the estimation of corneal height and prediction error in two settings, the Hadassah Hospital, Ophthalmology Department, Jerusalem, Israel and Clínica Barraquer, Bogotá, Colombia. Methods: In this retrospective case series , optical biometer measurements were taken for 63 highly myopic patients (spherical power ≤ 5 D) undergoing uneventful crystalline lens phacoemulsification and insertion of an acrylic intraocular lens. Prediction errors were obtained, with estimations of ± 0.50 D, ± 1.00 D, and greater than ± 2.00 D. A method to improve the corneal height calculation is described. Results: The SRK/T formula (mean absolute error [MAE] = 0.418; median absolute error [MedAE] = 0.352) was the most accurate, followed by the T2 (MAE = 0.435; MedAE = 0.381) and Holladay 1 (MAE = 0.455; MedAE = 0.389) formulas. Both the SRK/T and T2 formulas overestimated corneal height, but values were higher with the T2 formula. Corneal height was more precisely estimated using an alternative method that, when combined with axial length optimization, resulted in lower MAE (0.425) and MedAE (0.365) values than when applying the T2 formula alone. Conclusions: The T2 formula seems to be less accurate than the SRK/T formula in highly myopic eyes. An improved corneal height estimation method is described for the the T2 formula.
A case report of disseminated nocardiosis with ocular involvement in myasthenia gravis patient and literature review
Authors: wang shuhui , Jiang Bin , Li Yao , Shang Yanchang , Liu Zhengshan , Zhang Yongbo
Published: May 2019

Background

Nocardiosis is a rare and life-threatening opportunistic infection in the immunocompromised patients. Myasthenia gravis (MG) patients have the potential risk of nocardia infection because of the use of immunosuppressive agents. To date, only 7 cases of patients with MG have been reported to have nocardiosis. Disseminated nocardiosis with ocular involvement in MG patient haven’t been reported.

Case presentation

A 66-year-old man with MG, receiving treatment of methylprednisolone and azathioprine, was found to have respiratory infection. He also had heterogeneous symptoms with skin, brain and ocular manifestations. Nocardia bacteria was verified by the culture of puncture fluid, and the diagnosis of disseminated nocardiosis was made. Except for the left eye blindness, the patient completely recovered from the disease with combination antibiotic therapy. To further understand nocardiosis in patients with MG, we reviewed previous relevant literatures. According to all the literatures, this is the first report of disseminated nocardiosis with ocular involvement in MG patient.

Conclusions

MG patients with immunosuppressant treatments have the potential risk of rare nocardia infection, and a favourable prognosis can be achieved through early diagnosis and appropriate antibiotic therapy.
Variation of the digester temperature in the annual cycle – using the digester as heat storage
Authors: Hubert C. , Steiniger B. , Schaum C. , Michel M. , Spallek M.
Published: May 2019

Regarding digesters, present guidelines assume that the temperature must be kept constant in order to achieve process stability and that there is a drop in gas production between 40 and 50 °C. Nevertheless, observations of full-scale application show that fluctuations in temperature between mesophilic and thermophilic environments is indeed possible without any loss in biogas production performance. This would be particularly favourable because the digester can thus act as a heat storage. In order to validate temperature fluctuations on full-scale digesters the data of two digesters from different wastewater treatment plants (WWTPs) with high temperature fluctuations were analyzed. In addition, chemical oxygen demand (COD) balances for different temperature ranges were conducted in order to evaluate the process stability. The results show that fluctuations between mesophilic and thermophilic conditions can be achieved without a decrease in biogas production. Increasing the temperature above 50 °C leads to an increase in organic acid concentration as described in the literature. Nevertheless, the total concentration of organic acid was still at an uncritical level below 500 mg/L. The COD balance shows no significant difference between 38 °C, 44 °C and 51 °C. The rate of temperature fluctuations per day specifically seems to be a main factor for process stability rather than temperature itself.
The equilibrium and fixed-bed study of malachite green adsorption on chitosan hydrogels
Authors: Song X. H. , Goh K. L. , Wang K.
Published: May 2019

Chitosan hydrogel beads were prepared by a precipitation process, and were used to investigate the adsorption of malachite green (MG) oxalate under various conditions. It was found that adsorption equilibrium was most sensitive to the pH value at pH <8 while fixed bed breakthrough kinetics presented asymmetric S-shaped profiles which could not be adequately described by conventional models such as Adams-Bohart and Yoon-Nelson. The possible reasons were discussed and an improved Adams-Bohart model was proposed to better describe the changes in mass transfer mechanisms during adsorption.
PAH Therapies in Men: Often Wondered, Seldom Asked
Authors: Williamson Timothy
Published: May 2019

Note from the Section Editor: Though this issue of Advances in Pulmonary Hypertension is dedicated to specific challenges faced by women, we took this opportunity to ask Dr Williamson some of the more common questions asked by men with PAH.
Screening for Pulmonary Arterial Hypertension
Authors: Leary Peter J. , Edelman Jeffrey D.
Published: May 2019

Screening for disease before the arrival of symptoms is an intuitive cornerstone of preventive medicine and good clinical practice in many cases. However, screening is not appropriate for all conditions. Disease, test, and treatment should all be considered when developing a rational approach to screening.1–4 Specifically, screening may be warranted if the target disease has significant morbidity and mortality. Testing in specific populations should be able to detect early disease, have relatively low risk, and a low rate of pseudo-disease detection (including both false positive results and true disease which naturally regresses). Lastly, treatments should be more effective if employed early.56 This article reviews the available literature addressing these key aspects of screening for pulmonary arterial hypertension (PAH).
Importance of Early Diagnosis
Authors: Elliott C. Gregory , Humbert Marc , Newman John , Sandoval Julio
Published: May 2019

During the American Thoracic Society's International Conference 2012 in San Francisco in May, Dr Greg Elliott, guest editor of this issue of Advances in Pulmonary Hypertension on early diagnosis of pulmonary hypertension, invited Drs Marc Humbert, John Newman, and Julio Sandoval to convene one morning for an invigorating discussion relating their experiences, concerns, and suggestions for strategies to improve time to accurate diagnosis of pulmonary hypertension.
The Essential Role of Imaging in the Evaluation of Patients With Pulmonary Arterial Hypertension in Association With Congenital Heart Disease
Authors: Scognamiglio Giancarlo , Babu-Narayan Sonya V. , Rubens Michael B. , Gatzoulis Michael A. , Li Wei
Published: May 2019

Pulmonary arterial hypertension (PAH) is a hemodynamic and pathophysiologic condition defined as an increase in mean pulmonary artery pressure (MPAP) of ≥25 mm Hg at rest measured at right heart catheterization (RHC).12 Patients with PAH associated with congenital heart disease (PAH-CHD) are a growing population consisting of an anatomically and phenotypically heterogeneous group, where differences among specific cardiac defects, along with their varied clinical course and prognosis, influence treatment choices for the individual patient.
Targeted Pulmonary Arterial Hypertension Therapies and a Combined Medical-Surgical Approach for Congenital Heart Disease Patients
Authors: Zuckerman Warren A. , Rosenzweig Erika B.
Published: May 2019

Pulmonary arterial hypertension (PAH) with increased pulmonary vascular resistance (PVR) is a frequent complication of congenital heart disease (CHD), most commonly occurring with systemic-to-pulmonary shunt lesions. The natural disease progression involves pulmonary endothelial damage due to exposure to increased pulmonary blood flow and pressure, and in its most severe form results in Eisenmenger syndrome (ES), in which there is shunt reversal and cyanosis. Due to anatomic and histopathologic similarities of PAH in patients with CHD, as well as those with idiopathic and other forms of Group 1 PAH, there is an evolving interest and role for the use of the newer targeted PAH therapies in CHD patients. While early closure of shunt lesions is the best preventive measure, the use of targeted medical therapies when a patient is too high risk for surgery, following surgical repair, and even in those with reversal of shunting due to advanced disease, has emerged over the past decade.
Surgically Curable Pulmonary Hypertension: A View From the Experts
Authors: Tapson Victor F. , Auger William , Fedullo Peter , Mayer Eckhard , McGregor Christopher
Published: May 2019

Five physicians addressed important issues in the diagnosis and management of patients with pulmonary thromboembolic disease. The roundtable discussion was moderated by Victor F. Tapson, MD, Associate Professor of Medicine, Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina, and included William Auger, MD, Professor of Clinical Medicine, University of California, San Diego, Medical Center, San Diego, California; Peter Fedullo, MD, Clinical Professor of Medicine, University of California, San Diego, Medical Center; Eckhard Mayer, MD, Professor of Thoracic Surgery, Department of Cardio-Thoracic Surgery, University Hospital, Mainz, Germany; and Christopher McGregor, MD, Professor of Surgery, Consultant in Cardio-Thoracic Surgery, and Director of the Mayo Clinic William J von Liebig Transplant Center, Rochester, Minnesota.
Pulmonary Arterial Hypertension in Congenital Heart Disease: Controversies and Consensus
Authors: Barst Robyn , Wessel David , Bridges Nancy , Ivy Dunbar
Published: May 2019

Four physicians discussed current and future strategies for the assessment and treatment of pulmonary arterial hypertension (PAH) related to congenital heart disease.

The roundtable discussion was moderated by Robyn Barst, MD, Professor of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York, and included David Wessel, MD, Professor of Pediatrics and Anesthesia, Harvard Medical School, and Senior Associate in Cardiology and Anesthesia at Children's Hospital, Boston; Nancy Bridges, MD, Chief of the Clinical Transplantation Section, National Institute for Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland; and Dunbar Ivy, MD, Associate Professor of Pediatrics, Chief and Selby Rickenbaugh Chair of Pediatric Cardiology, Director of the Pediatric Pulmonary Hypertension Program, University of Colorado, and Denver Children's Hospital.
Pulmonary Hypertension Roundtable
Authors: McLaughlin Vallerie V. , Channick Richard N. , Robbins Ivan M. , Tapson Victor F.
Published: May 2019

In this discussion four experts shared insights on what might be considered the “gestalt” of diagnosing and monitoring pulmonary arterial hypertension. They ranged over a broad spectrum of issues that included thromboembolic pulmonary hypertension, exercise testing, hemodynamics, imaging studies, and response to therapy. The discussion was moderated by Vallerie V. McLaughlin, MD, Associate Professor of Medicine, Director, Pulmonary Hypertension Program, University of Michigan Health System, Ann Arbor, Michigan. The participants included Richard N. Channick, Associate Professor of Medicine, Pulmonary and Critical Care Division, University of California, San Diego Medical Center, San Diego, California; Ivan M. Robbins, MD, Director, Pulmonary Hypertension Center, Vanderbilt University, Nashville, Tennessee; and Victor F. Tapson, MD, Professor of Medicine, Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina.
Meeting the Challenge of Surgery and Pulmonary Hypertension: How to Manage the “Hemodynamic Environment” to Optimize Outcomes
Authors: Channick Richard , McCurry Kenneth R. , Pearl Ronald , Rich Stuart
Published: May 2019

This discussion was moderated by Richard Chan-nick, MD, Associate Professor of Medicine, Pulmonary and Critical Care Division, University of California, San Diego Medical Center, San Diego, California. Panel members included Kenneth R. McCurry, MD, Assistant Professor of Surgery, Division of Cardiothoracic Surgery, Director, Lung and Heart-Lung Transplantation Programs, University of Pittsburgh Department of Surgery, Pittsburgh, Pennsylvania; Ronald Pearl, MD, PhD, Professor and Chair, Anesthesia Department, Stanford University School of Medicine, Stanford, California; and Stuart Rich, MD, Professor of Medicine, Section of Cardiology, Center for Pulmonary Hypertension, University of Chicago, Chicago, Illinois.
Lung Transplantation and Idiopathic Pulmonary Arterial Hypertension: A Case Study
Authors: Lawrence E. Clinton , Fisher Micah R.
Published: May 2019

Over the past decade effective medical treatments for idio- pathic pulmonary arterial hypertension (IPAH) have de- creased but not eliminated the need for lung transplantation for this disease. Timing of referral for transplant and listing remain critical judgments in the management of many PAH patients but are still subjects of significant debate. National initiatives that have increased donor organs overall and changed their distribution have changed previous decision- making for many centers. A case is presented that illustrates issues in managing the patient in whom medical therapy has failed.
Roundtable Discussion of the Impact of the 4th World Symposium on Pulmonary Hypertension
Authors: Barst Robyn J. , Humbert Marc , Robbins Ivan M. , Rubin Lewis J. , Park Robyn J.
Published: May 2019

A discussion among attendees of the 4th World Symposium on Pulmonary Hypertension took place to share “an insider's look” into the current and future research and treatment implications in pulmonary hypertension. Myung H. Park, MD, guest editor of this issue of Advances in Pulmonary Hypertension, Assistant Professor of Medicine and Director, Pulmonary Vascular Diseases Program, Division of Cardiology, University of Maryland School of Medicine, Baltimore, moderated the discussion. Participants included Robyn Barst, MD, Professor Emerita, Columbia University, New York; Marc Humbert, MD, PhD, Universite Paris-Sud, French Referal Center for Pulmonary Hypertension, Hopital Antoine-Beclere, Assistance Publique Hopitaux de Paris, Clamart, France; Ivan Robbins, MD, Associate Professor of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; and Lewis J. Rubin, MD, Clinical Professor, Department of Medicine, University of California, San Diego.
Pulmonary Hypertension and Lung Transplantation
Authors: Levine Deborah Jo , Park Myung , Perrot Marc de , Girgis Reda
Published: May 2019

A discussion on current practice, challenges, and emerging opportunities in lung transplantation for pulmonary hypertension patients was led by guest editor Deborah Jo Levine, MD, of the University of Texas Health Science Center at San Antonio. Joining her were Marc de Perrot, MD, a thoracic surgeon at Toronto General Hospital, Toronto, Ontario, Canada; Reda Girgis, MD, Associate Professor of Medicine, Johns Hopkins Hospital, Baltimore, Maryland; and Myung Park, MD, Assistant Professor of Medicine, University of Maryland School of Medicine, Baltimore.
Clinical Drug Development for the Treatment of Pulmonary Arterial Hypertension: Collaboration With the Pharmaceutical Industry and Regulatory Agencies
Authors: Barst Robyn J.
Published: May 2019

Drug development is the entire process of introducing a new drug to the market. It involves drug discovery, screening, preclinical testing, an Investigational New Drug (IND) application in the US or a Clinical Trial Application (CTA) in the EU, phase 1–3 clinical trials, a New Drug Application (NDA), Food and Drug Administration (FDA) review and approval, and postapproval studies required for continuing safety evaluation. Preclinical testing assesses safety and biologic activity, phase 1 determines safety and dosage, phase 2 evaluates efficacy and side effects, and phase 3 confirms efficacy and monitors adverse effects in a larger number of patients. Postapproval studies provide additional postmarketing data. On average, it takes 15 years from preclinical studies to regulatory approval by the FDA: about 3.5–6.5 years for preclinical, 1–1.5 years for phase 1, 2 years for phase 2, 3–3.5 years for phase 3, and 1.5–2.5 years for filing the NDA and completing the FDA review process. Of approximately 5000 compounds evaluated in preclinical studies, about 5 compounds enter clinical trials, and 1 compound is approved (Tufts Center for the Study of Drug Development, 2011). Most drug development programs include approximately 35–40 phase 1 studies, 15 phase 2 studies, and 3–5 pivotal trials with more than 5000 patients enrolled. Thus, to produce safe and effective drugs in a regulated environment is a highly complex process. Against this backdrop, what is the best way to develop drugs for pulmonary arterial hypertension (PAH), an orphan disease often rapidly fatal within several years of diagnosis and in which spontaneous regression does not occur?
Protective Effect of Edaravone on Cyclophosphamide Induced Oxidative Stress and Neurotoxicity in Rats
Authors: Singh Sanjiv , Kumar Abhishek
Published: May 2019

Background:

Cyclophosphamide (CPA) is the most widely prescribed cancer chemotherapeutic agent which shows serious neurotoxic side effect. Generation of reactive oxygen species at the cellular level is the basic mechanism of cyclophosphamide induced neurotoxicity. Edaravone is the synthetic drug used for brain stroke and has potent antioxidant property.

Objective:

This study aimed to investigate the effect of edaravone on neurobehavioral and neuropathological alteration induced by cyclophosphamide in male rats.

Methods:

Twenty eight Sprague-Dawley rats were equally divided into four groups of seven rats in each. The control group received saline, and other groups were given CPA intraperitoneally (100 mg/kg), CPA (100 mg/kg) intraperitoneally + Edaravone (10 mg/kg) orally, or Edaravone (10 mg/kg) orally for one month.

Results:

Our data showed that CPA significantly elevated brain AChE activity in the hippocampal region. A decrease in the total antioxidant capacity and a reduction in the CAT, SOD, and GPX activity occurred in the brains of the rats exposed to CPA. CPA-treated rats showed a significant impairment in long-termmemory and motor coordination. These results were supported by histopathological observations of the brain. Results revealed that administration of edaravone reversed AChE activity alternation and ameliorated behavioral and histopathological changes induced by CPA.

Conclusion:

This study suggests that co-administration of edaravone with cyclophosphamide may be a useful intriguing therapeutic approach to overcome cyclophosphamide induced neurotoxicity.
SCIENTIFIC AND TECHNICAL PROBLEMS OF IMPROVEMENT TRAINING SYSTEMS FOR RADAR OF HIGH FACTORY READINESS UHF RANGE
Authors: Bugaev V. S. , Yakubovskiy S. V.
Published: May 2019

Perspective direction of improvement of information system products for military purposes is the creation of a radar station of high factory readiness UHF. One of the important features of this radar is the presence in the composition of the staff training system to prepare crew operating the radar. In the article based on the experience of developing the problems of improving UTS, the optimal composition of products containing two main components: the training complex, including hardware and software, and methodological complex including methodological support for training. In addition, determine the forms and methods of learning, UTS, scientific and technical problems of improvement and future directions of development of the means for training combat crews as well as their use in military educational organizations.
CONCEPTUAL MODEL OF THE SYSTEM OF SPECIAL TYPES OF TECHNICAL SUPPORT
Authors: Mironov A. N. , Lisitskiy V. V.
Published: May 2019

In the article on set-theoretic level, developed a conceptual model of the system of special types of technical support for difficult organizational-technical system. The purpose of conceptualizing the creation of a system of interrelated and stemming from one of the other views on certain objects, phenomena, processes associated with the system of special types of technical support. In the development of applied concepts and principles of the methodology of system approach. The empirical basis for the development of the conceptual model has served many fixed factors obtained in the warning system and require formalization and theoretical explanation. The novelty of the model lies in the account of the effect of environment directly on the alert system. Therefore, in the conceptual model of the system of special types of technical support included directly in the conceptual model of the system of special types and conceptual model of the environment. Part of the conceptual model of the environment is included in the conceptual model of the enemy of nature and co-systems.
SPACE SURVEILLANCE SYSTEM’S SAR SIGNAL DETECTION RESULTS
Authors: Ksendzuk A. V. , Kanatchikov A. A. , Gerasimov P. A.
Published: May 2019

Special aspects of space objects radiotechnical surveillance system used for filling the space tracking and surveillance system (STSS) satellite catalogue described and analyzed. Special emphasis placed on spaceborne synthetic aperture radar signals detection. Parameters of the SAR signals estimated with the proposed radiotechnical surveillance system described. Two processing methods for unknown and partially known signals proposed and analyzed. Signal detection with incompletely known parameters performs with cumulative second-order statistic. Signal detection with unknown parameters performs for periodic signal in assumption that observation interval exceed pulse repetition frequency. Proposed methods implemented in hardware demonstrator of radiotechnical surveillance system. This demonstrator works in real-time on Field Programmable Gate Array or save data on storage device for post-processing. L-band Palsar2 signal detection results presented and analyzed. Further work for hardware and software optimization described.