bluuebunny/crossref_metadata_2025 huggingface dataset:
Sixteen-Year Follow-up of Talar Body Prosthesis and Total Ankle Arthroplasty After Traumatic Talar Extrusion
Authors: Benson Austin , Alvine Frank , Alvine Greg
Published: March 2021

Case:

We report a case of an extruded talus treated with an agility custom talar body prosthesis with total ankle arthroplasty 2 years after the injury. At the 16-year follow-up, the patient has performed remarkably well. At postoperative year 15, she required 1 additional surgery in which the polyethene was exchanged and the medial and lateral gutters were debrided.

Conclusion:

Talar body prothesis with total ankle arthroplasty may be a viable option for extrusion of the talus.
Increasing Well Efficiencies While Lowering Carbon Emissions Through the Use of Releasable Mooring System
Authors: Pasternak Jason , Shelton John , Patterson Nick , Leirvåg Jan Petter
Published: March 2021

Releasable Mooring Systems ("RMS") have been in use for over 35 years in the offshore industry, with an original purpose of rapidly releasing lines to avoid weather events, such as ice floes, hurricanes, or cyclones. With the recent introduction to industry of fully redundant release tools with higher release load capabilities, the RMS concept is now being used in well planning efficiencies. The objective of the paper is to show the effectiveness of the latest enabling tool and RMS concept in reducing the time to unmoor, removing the requirement for an Anchor Handling Tow Supply (AHTS) vessel, and assisting Dynamically Positioned (DP)/Moored semisubmersibles in lowering their carbon footprint, operational costs and HSE exposure.
High-Precision Drill Bit Tracking
Authors: Houbiers Marianne , Bussat Sascha , Schopper Florian , Hansteen Fredrik
Published: March 2021

The lateral well position uncertainty of magnetic/gyro MWD measurements can often exceed the requirements regarding anti-collision, for optimal placement of infill wells between existing producers, or for hitting targets with limited geological extent. The positional uncertainty can be significantly reduced by implementing high-precision drill-bit localization using passive seismic data. Consequently, not only drilling risks can be reduced, but optimal reservoir drainage is ensured as well.

By utilizing passive seismic recordings from the seafloor, we can "listen" to the noise generated by the BHA while drilling. Despite various noise sources in the vicinity (e.g. vessels and rigs), advanced data processing and the combination of hundreds of seafloor receivers spread above the ongoing drilling, enable us to detect the drilling signal and locate the drill bit. Whereas the magnetic and gyro MWD tools have errors that accumulate with measured depth, each bit position derived from seismic (usually every 90 seconds) is completely independent. For horizontal sections, the error does not increase with measured depth, and hence can provide improved lateral accuracy. No additional BHA tool is required and the measurements are neither dependent on the magnetic nor gravitational field. Moreover, the passive seismic measurements can be used to obtain an improved lateral well position estimate. This is done by optimizing the azimuth information of the well trajectory in the minimum curvature method. A lateral uncertainty measure can be derived from the residuals between the passive measurements and the updated well path.

Since 2018, we have used the continuous stream of passive data from permanent seafloor sensors at the Grane field with its reservoir depth of around 1800 m TVDSS to follow all wells with this drill bit tracking scheme. Lateral deviations from the magnetic/gyro measurements of up to 20m have been observed. The lateral position uncertainty can be as low as a couple of meters under optimal conditions.
Automatic Drilling Fluids Monitoring
Authors: Taugbøl Knut , Sola Bengt , Forshaw Matthew , Fjogstad Arild
Published: March 2021

The drilling fluid is the primary barrier against well control incidents when drilling a well in conventional mode and the drilling fluid properties must be correct at all times to prevent well control incidents. Automatic drilling fluid monitoring through automated measuring techniques combined with real time data transfer into control center with 24/7 surveillance substantially improves this control compared to conventional methods relying on manual measurements with long sampling intervals.

New measurement devices have been introduced to the industry which measure the drilling fluid properties of all fluid going into the well as well as fluid coming out from the well. Properties measured are among others density and a full rheology profile. The data are transferred to users on the rig as well as directly to onshore operation centers. This highly improves the fluid engineering, enabling a more precise diagnostician and treatment in real time. This also improves efficiency when performing displacements from one fluid system to another.

This paper will present new units for automatic drilling fluids measurements and its use in offshore drilling. The surveillance of fluid properties and the use of data at an onshore operation center will be presented. The drilling fluid properties are also detrimental for drilling parameters such as ECD (equivalent circulating density), surge and swab pressures and hole cleaning properties and the added data will improve any estimation of such parameters. The paper will present experiences from use of these data into advanced real time hydraulic measurements and models for automatic drilling control and explain how this can improve safety in the drilling operations as well as improve the drilling efficiency.
Ten Years After the Deepwater Horizon Accident: Regulatory Reforms and the Implementation of Safety and Environmental Management Systems in the United States
Authors: Nieves-Zárate Margarita
Published: March 2021

The Deepwater Horizon accident is one of the major environmental disasters in the history of the United States. This accident occurred in 2010, when the Deepwater Horizon mobile offshore drilling unit exploded, while the rig's crew was conducting the drilling work of the exploratory well Macondo deep under the waters of the Gulf of Mexico. Environmental damages included more than four million barrels of oil spilled into the Gulf of Mexico, and economic losses total tens of billions of dollars. The accident brought into question the effectiveness of the regulatory regime for preventing accidents, and protecting the marine environment from oil and gas operations, and prompted regulatory reforms. Ten years after the Deepwater Horizon accident, this article analyzes the implementation of Safety and Environmental Management Systems (SEMS) as one of the main regulatory reforms introduced in the United States after the accident. The analysis uses the theory of regulation which takes into account both state and non-state actors involved in regulation, and therefore, the shift from regulation to governance. The study includes regulations issued after the Deepwater Horizon accident, particularly, SEMS rules I and II, and reports conducted by the National Academy of Sciences, the National Commission on the BP Oil Spill, the Center for Offshore Safety, the Chemical Safety and Hazard Investigation Board, and the Bureau of Safety and Environmental Enforcement (BSEE). The article reveals that though offshore oil and gas operators in the U.S. federal waters have adopted SEMS, as a mechanism of self-regulation, there is not clarity on how SEMS have been implemented in practice towards achieving its goal of reducing risks. The BSEE, as the public regulator has the task of providing a complete analysis on the results of the three audits to SEMS conducted by the operators and third parties from 2013 to 2019. This article argues that the assessment of SEMS audits should be complemented with leading and lagging indicators in the industry in order to identify how SEMS have influenced safety behavior beyond regulatory compliance. BSEE has the challenge of providing this assessment and making transparency a cornerstone of SEMS regulations. In this way, the lessons of the DHW accident may be internalized by all actors in the offshore oil and gas industry.
Better Automatic Interpretation of Cement Evaluation Logs through Feature Engineering
Authors: Viggen Erlend Magnus , Løvstakken Lasse , Merciu Ioan Alexandru , Måsøy Svein-Erik
Published: March 2021

We build systems to automatically interpret cement evaluation logs using supervised machine learning (ML). Such systems can provide instant rough interpretations that may then be used as a basis for human interpretation. Here, we compare the performance of two approaches: A previously published approach based on deep convolutional neural networks (CNNs) that autonomously learn to extract features from well log data, and a feature-engineering approach where we use our own domain knowledge to extract features.

We base this work on a dataset of around 60 km of well log data. Specialist interpreters have classified these logs according to the bond quality (6 ordinal classes) and hydraulic isolation (2 classes) of solids outside the casing. We train the ML systems to reproduce these reference interpretations in segments of 1 m length. The CNNs directly receive log data as a collection of 2D images and 1D curves. In the feature-engineering approach, we combine the extracted features with various classifiers.

For bond quality, the CNNs’ interpretation exactly matches the reference 51.6% of the time. 88.5% of the time, it does not miss by more than one class. For hydraulic isolation, the CNNs match the reference 86.7% of the time. The best-performing feature-based classifier, which is an ensemble of individual classifiers, provides better results of 57.4%, 89.5%, and 88.9%, respectively.

Our results indicate two main reasons why feature-based classifiers may perform particularly well on this task. First, there is some subjectivity inherent in the well log interpretations that are used to train and test ML systems. Second, well logs comprise many different and complex pieces of data. For these reasons, this dataset may be particularly liable to overfitting. This may favour approaches based on feature engineering, where we apply our domain knowledge to extract a few pieces of essential information from the data instead of leaving the job of understanding the data to an ML system that may misinterpret spurious patterns as generalisable. It may also favour simpler classifiers with less overfitting capacity.

This article shows how petroleum researchers and engineers can implement automatic interpretation systems for cement evaluation logs using ML methods that are relatively easy to apply and deploy, with better results than an approach based on autonomous feature extraction. This approach could also be adapted for automatic interpretation of other types of well log data.
Ensuring Success of Complex Liner Deployment Over Complete Field Development Campaign
Authors: Brillaud Loïc , Couliou Florent , Mathisen Kim , Koløy Tom Rune , Lacaze Chloé , Balou Efficience , Bledou Manfred , Delabrousse-Mayoux Géraud , Drevillon Pierre-Marie
Published: March 2021

This paper describes the innovative engineering workflow which has been used to ensure the safe deployment of deep production liners on long step-out wells of a deep offshore development field.

It highlights the importance of accurate Torque & Drag modelling during planning and operations and provides details on how the use of downhole data assisted in understanding downhole conditions on the first wells, which allowed to optimize the running and setting procedure for the next wells of the field.

For this methodology, a unique Torque & Drag stiff-string model was used to simulate the evolution of side-forces, tension, stretch, torque and twist along the string at every stage of the deployment and setting of the liner. Simulations were performed both during planning phase and operations. Once the well completed, downhole memory data from a logging tool was compared with simulations, which allowed to calibrate the model, better understand downhole conditions, and provide recommendations for the next runs.

Using this methodology, the operator succeeded in deploying the liner to total depth, setting the hanger and packer successfully on all the wells of the field. These operations were performed with only 40 minutes of non-productive time throughout the campaign. The paper shows how correlating downhole data with Torque & Drag simulations highlighted areas of improvement and allowed to optimize the running and setting procedure of the liner. It also led the operator to gain confidence in the feasibility of such critical operations even on the more challenging wells. Detailed engineering and collaboration were key to this success. Such methodology can be applied on every well where weight transfer is a potential issue.

As the industry is heading towards digitalization and automation, this case study is a prime example which demonstrates the added value of combining advanced physics-based simulations with time based downhole data.
Implementing a Strategy for Shale as Well Barrier in New Wells
Authors: Kristiansen Tron Golder , Delabroy Laurent , Obando Palacio Guillermo Andres , Winther Tonje , Aarseth Nils Andre , Bauer Andreas , Hagenes Karstein , Lindal Anders , Tyberø Pål
Published: March 2021

Shale is an effective barrier material. It has a proven track record of acting as a seal (barrier) for oil and gas reservoirs for millions of years. Shale with high clay content and especially high smectite has low permeability, in the nanodarcy range, compared to standard class G laboratory cement that has permeability in the 10–20 microdarcy range. Weak ductile shales will also have a self-healing behavior should fractures be induced at some point. Shale is approved by regulators to be used as well barriers and part of permanent plug and abandonment (P&A) for oil and gas wells.

Examples of regulations are Norsok D-010, 2013 in Norway and O&G UK, 2012. In Norsok D-010, one suggests the formation of shale barriers to happen due to creep in ductile shales. Creep occurs in many materials and is observed as deformation under constant load and is also well described in rock mechanics literature. In a previous paper (Kristiansen et al., 2018), it was discussed how shale can be activated as a barrier to form around the wellbore in some shale types. This can be done by inducing a pressure drop in the open annulus (rapid drawdown), by heating the shale by a couple of hundred degrees Celsius, or by chemical processes. In that paper, the process found most effective and practical at that time was demonstrated: the activation of shale barriers with a rapid pressure drop in the annulus. It was also shown that the barrier can be verified days after by standard verification methods used in the industry (pressure testing and bond logging). The shale barrier verification criteria are analogous to cement barriers.

In this paper we share the experience from the implementation of a strategy to use shale as well barriers in new wells at Valhall and a second field, Ula, around 100 km away. The method used to activate the shale barriers has revealed some challenges from a well control point of view, but it has also shown that waiting a couple of weeks, or in some cases a couple of months, shale barriers are forming with the same quality as when they were activated or logged later as part of P&A. From this work it can be concluded that the shale barriers logged during P&A are, in some cases, in place only weeks or months after the wells have been drilled. The activation seems to induce an acceleration of time-dependent deformation that will naturally happen over longer time and is consistent with rock mechanics principles of time-dependent deformations in rocks (like creep and consolidation).
Development, Testing and Validation of an Adaptive Drilling Optimization System
Authors: Daireaux Benoit , Ambrus Adrian , Carlsen Liv A. , Mihai Rodica , Gjerstad Kristian , Balov Mohsen
Published: March 2021

An important benefit of drilling automation is the ability to ensure continuous updating of the parameters controlling the drilling process according to the current wellbore conditions. While actively drilling, this means continuously adjusting the weight on bit (WOB), topdrive speed and flowrate according to the current formation properties and drilling system behaviour: ability to transport cuttings, buckling or exceeding the geo-pressure margins. We present here the main principles used to design and develop such an adaptive drilling optimization system, and the first results obtained both in a simulated environment and in real operations.

The system achieves adaptability by combining two separate processes. Firstly, it maintains an updated estimate of the bit-rock interaction mechanism using a stochastic approach coupled with a physical model. This is used to predict the system's response to changes in parameters (WOB, topdrive speed or flowrate), including the possible presence of a founder point, i.e. a WOB threshold above which no gain in rate of penetration (ROP) is achieved, and also to detect changes in formation properties. Then, the second process ensures that the effects of the same drilling parameters are evaluated with respect to their ability to ensure safe drilling: cuttings transport and drillstring mechanical stability are the main constraints here, evaluated in a probabilistic framework. The combination of these two processes provides the generation of both safe and optimum drilling parameters.

The system can be used in two contexts: firstly, as an advisory module which provides set-point recommendations to the driller; secondly, as an integrated module into a drilling automation system. In the latter configuration, the generated set-points are used to actively control the drilling process. Note that the bit-rock interaction prognoses enable quick automated detection of – and therefore reaction to- sudden changes in formation properties. Both modes facilitate real-time monitoring of the bit-rock interaction process, including the estimated formation properties, bit aggressiveness and founder point. Results from active tests in a simulated environment and advisory mode against real field data are presented and discussed.
Systematic Selection of Drill-In and Completion Fluids for Development of the Dvalin HT Gas Field - Part II: Successful Clean-Up Validates Experimental Qualification Approach
Authors: Czuprat Oliver , Eriksen Kjetil , Clinch Duncan , Byrski Piotr , Gibbons Garbhan , Hughes Neal , Øian Tore , Ritschel Robert , Storhaug Jens
Published: March 2021

Formation damage by the drill-in fluid has been identified as a major risk for the Dvalin HT gas field. To ensure the long-term stability and mobility of the mud even after an extended suspension time between drill-in and clean-up of the wells, a novel static aging test under downhole temperature and high pressure was conducted. Experiments have shown that the downhole stability is commonly underestimated when the surrounding pressure is lower than in the field. Thus, a high-pressure cylinder was used in vertical orientation in a heating oven with a pressure pump regulating the pressure up to 200 bar.

The reservoir section was drilled with the optimized organo-clay-free oil-based drilling fluid (OCFOBDF) specified in the qualification phase. Tracers in the lower completion were used to identify clean-up from the upper high-permeability streak and the deeper (relatively lower) high-permeability streak. Due to extended wait on weather after drilling and completion of the first of the four wells, the lag time until clean-up was almost 11 weeks (74 days).

It could be experimentally shown that the qualified OCFOBDF system weighted with micron sized barite remains mobile without phase separation even after static aging at 160 °C and 200 bar for the maximum estimated lag time between drilling and clean-up of 3 months. The absence of a gas cap in the set-up also better represents downhole conditions in the reservoir section and has shown that it improves the fluid´s stability. The clean-up of the well was successful with a maximum flowrate of 3.0 MM Sm3/d. Analysis of the tracers has proven that clean-up was successful for the entire reservoir section, including the deeper part.

It could be concluded that in alignment with the lab tests that the mud fulfilled its requirement to be mobile even up to three months. Because of the superior properties, settling of solids (bridging and weighting material) could be avoided, resulting in no blockage of the (lower part of the) reservoir.

The use HPHT aging has been the key to proving the long-term stability and mobility of the combined Drill-In and Completion Fluid. This technique falls outside of current API RP testing practices but is believed to be highly beneficial for qualification of fluids that will be left in the lower completion for long periods, especially in open hole completions under high temperature and pressure.
Evaluating Data-Driven Techniques to Optimize Drilling on the Moon
Authors: Joshi Deep R , Eustes Alfred W , Rostami Jamal , Dreyer Christopher
Published: March 2021

Several companies and countries have announced plans to drill in the lunar South Pole in the next five years. The drilling process on the Moon or any other planetary body is similar to other exploration drilling by using rotary drills, for example the oil and gas drilling. However, the key performance indicators (KPIs) for this type of drilling are significantly different. This work aimed to develop the drilling optimization algorithms to optimize drilling on the Moon based on the experiences with the terrestrial drilling in related industries.

A test drilling unit was designed and fabricated under a NASA Early Stage Innovation (ESI) grant; A high-frequency data acquisition system was used to record drilling responses at 1000 Hz. Parameters like weight on bit (WOB), torque, RPM, rate of penetration (ROP), mechanical specific energy (MSE), field penetration index (FPI), and the uniaxial compressive strength (UCS) were recorded for 40 boreholes in the analog formations. This work utilizes the large dataset comprising of more than 1 billion data points recorded while drilling into various lunar analogous formations and cryogenic lunar formations to optimize power consumption and bit wear during drilling operations.

The dataset was processed to minimize the noise. The effect of drilling dysfunctions like auger choking and bit wear was also removed. Extensive feature engineering was performed to identify how each of the parameter affects power consumption and bit wear. The data was then used to train various regression algorithms based on the machine learning approaches like the random forest, gradient boosting, support vector machines, logistic regression, polynomial regression, and artificial neural network to evaluate the applicability of each of these approach in optimizing the power consumption using the control variables like RPM and penetration rate. The best performing algorithm based on ease of application, runtime, and accuracy of the algorithm was selected to provide recommendations for ROP and RPM which would result in minimum power consumption and bit wear for a specific bit design.

Since the target location for most lunar expeditions is in permanently shadowed regions, the power available for a drilling operation is extremely limited. The bit wear will significantly affect the mission life too. Algorithms developed here would be vital in ensuring efficient and successful operations on the Moon leading to more robust exploration of the targeted lunar regions.
A Generalised Solution to the Point to Target Problem Using the Minimum Curvature Method
Authors: Sawaryn Steven J.
Published: March 2021

An explicit solution to the general 3D point to target problem based on the minimum curvature method has been sought for more than four decades. The general case involves the trajectory's start and target points connected by two circular arcs joined by a straight line with the position and direction defined at both ends. It is known that the solutions are multi-valued and efficient iterative schemes to find the principal root have been established.

This construction is an essential component of all major trajectory construction packages. However, convergence issues have been reported in cases where the intermediate tangent section is either small or vanishes and rigorous mathematical conditions under which solutions are both possible and are guaranteed to converge have not been published. An implicit expression has now been determined that enables all the roots to be identified and permits either exact, or polynomial type solution methods to be employed. Most historical attempts at solving the problem have been purely algebraic, but a geometric interpretation of related problems has been attempted, showing that a single circular arc and a tangent section can be encapsulated in the surface of a horn torus. These ideas have now been extended, revealing that the solution to the general 3D point to target problem can be represented as a 10th order self-intersecting geometric surface, characterised by the trajectory's start and end points, the radii of the two arcs and the length of the tangent section.

An outline of the solution's derivation is provided in the paper together with complete details of the general expression and its various degenerate forms so that readers can implement the algorithms for practical application. Most of the degenerate conditions reduce the order of the governing equation. Full details of the critical and degenerate conditions are also provided and together these indicate the most convenient solution method for each case. In the presence of a tangent section the principal root is still most easily obtained using an iterative scheme, but the mathematical constraints are now known. It is also shown that all other cases degenerate to quadratic forms that can be solved using conventional methods.

It is shown how the general expression for the general point to target problem can be modified to give the known solutions to the 3D landing problem and how the example in the published works on this subject is much simplified by the geometric, rather than algebraic treatment.
Development and validation of a prognostic nomogram for predicting the survival of HIV/AIDS adults who received antiviral treatment: a cohort between 2003 and 2019 in Nanjing
Authors: Jiang Fangfang , Xu Yuanyuan , Liu Li , Wang Kai , Wang Lu , Fu Gengfeng , Wang Liping , Li Zhongjie , Xu Junjie , Xing Hui , Wang Ning , Zhu Zhengping , Peng Zhihang
Published: March 2021

Background

Although great achievements have been made since free antiviral treatment (ART) was available, an in-time and accurate prediction of survival for people living with HIV (PLHIV) is still needed for effective management. We aimed to establish an effective prognostic model to forecast the survival probability of PLHIV after ART.
Methods

The participants enrolled were from a follow-up cohort between 2003 and 2019 in Nanjing from Nanjing AIDS Prevention and Control Information System. The nested case-control study was employed with HIV-related death, and propensity-score matching (PSM) approach was applied at a ratio of 1:4 to allocate the patients. Univariate and multivariate Cox hazards analyses were used based on the training set to determine the risk factors. The discrimination was qualified using the area under the curve (AUC) and concordance index (C-Index). The calibration was evaluated using the calibration curve. The clinical benefit of prognostic nomogram was assessed by decision curve analysis (DCA).
Results

Predictive factors including CD4 cell count (CD4), body mass index (BMI) and food blood glucose (GLU) were determined and contained in the nomogram. In the training set, AUC and C-index (95% CI) were 0.826 and 0.793 (0.740, 0.846), respectively. The model of validation set still revealed good discrimination with an AUC and a C-index (95% CI) of 0.750 and 0.776 (0.711, 0.839). The calibration curve also exhibited a high consistency in predicting the survival of PLHIV (especially in the first three years after starting ART). Moreover, DCA demonstrated that the nomogram was clinically beneficial.
Conclusion

The nomogram is effective and accurate in forecasting the survival rate of PLHIV, and therefore accessible for medical workers in health administration.
Postoperative Hypoalbuminemia: Prevalence, Risk Factors, Association with Postoperative Pneumonia in Brain Tumors Patients Undergoing Craniotomy
Authors: Zhao Da-wei , Zhang Xu-yang , Wei Kai-yan , Jiang Yi-bin , Liu Dan , Zhang Shui-xian , Feng Hua , Hu Rong
Published: March 2021

Hypoalbuminemia is associatied with poor outcome in patients undergoing surgery intervention. The main aim for this study was to investigate the incidence and the risk factors of postoperative hypoalbuminemia and assessed the impact of postoperative hypoalbuminemia on complications in patients undergoing brain tumor surgery. This retrospective study included 372 consecutive patients who underwent brain tumors surgery from January 2017 to December 2019. The patients were divided into hypoalbuminemia (< 35 g/L) and non-hypoalbuminemia group (≥ 35 g/L) based on postoperative albumin levels. Logistic regression analyses were used to determine risk factors. Of the total 372 patients, 333 (89.5%) developed hypoalbuminemia after surgery. Hypoalbuminemia was associated with operation time (OR 1.011, P < 0.001), preoperative albumin (OR 0.864, P = 0.015) and peroperative globulin (OR 1.192, P = 0.004). Postoperative pneumonia had a higher incidence in patients with than without hypoalbuminemia (41.1% vs 23.1%, P = 0.029). The independent predictors of postoperative pneumonia were age (OR 1.053, P < 0.001), operation time (OR 1.003, P = 0.013) and lower postoperative albumin (OR 0.946, P = 0.018). Postoperative hypoalbuminemia has a higher incidence with the increase of operation time, and is associated with postoperative pneumonia in patients undergoing brain tumor surgery.
Identification of the co-expression module-trait relationships and hub genes associated with the diffuse-type gastric cancer
Authors: Ye Zaisheng , Zheng Miao , Zeng Yi , Xie Yunqing , Wei Shenghong , Wang Yi , Lin Zhitao , Chen Shu , Wang Zhiwei , Zheng Qiuhong , Chen Luchuan
Published: March 2021

Diffuse-type gastric cancer (DGC) is a gastric cancer subtype based on Laurén histological type, with poor prognosis when compared intestinal-type gastric cancer. It is necessary that comprehensive analysis identifies pathways and genes involved in DGC. RNA expression data of DGC (including 52 samples, top 5000 genes) and fourteen patient clinic traits were downloaded from The Cancer Genome Atlas (TCGA) database. Co-expression modules and module-trait relationships were constructed by weighted gene co-expression network analysis (WGCNA). The identified ten co-expression modules were obtained from DGC samples. The co-expression turquoise module positively correlated with longest dimension. The co-expression magenta module positively correlates with gender, and person neoplasm cancer status. The co-expression green module also positively correlates with pathologic N stage and pathologic stage. Besides, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment obtained some cancer related signal pathways in the co-expression turquoise and green module, such as proliferation, drug resistance, cell metabolism. Additionally, we identified the hub genes in the co-expression turquoise, green and magenta modules. Protein-protein interaction (PPI) and biological processes (BP) analysis were performed on the hub genes in those modules, suggesting the key role of those modules in the development of the cancer. The hub genes were significantly related to Overall survival analysis showed some important hub genes were significant in DGC patients, including ANK2, GNAO1, MAP6, RERG (turquoise module), MEP1A, GUCY2C, ALDOB (green module), XIST, TTTY15, NCRNA00185, CYorf15B (magenta module). The study provided new biomarkers and potential mechanisms in DGC.
An effective prediction of biomagnification factors for organochlorine pollutants
Authors: Zhang Ming Cai , Zhai Hong Lin , Bi Ke Xin , Zhao Bin Qiang , Shao Hai Ping
Published: March 2021

Biomagnification factor (BMF) is an important index of pollutants in food chains but its experimental determination is quite tedious. In this contribution, as the feature descriptors of molecular information, Tchebichef moments (TMs) were calculated from their structural images. Then stepwise regression was employed to establish the prediction model for the logBMF of organochlorine pollutants. The correlation coefficient with leave-one-out cross-validation (Rcv) was 0.9570; the correlation coefficient of prediction (Rp) and root mean square error (RMSEp) for external independent test set reached 0.9594 and 0.2129, respectively. Compared with traditional two-dimensional (2D) quantitative structure-property relationship (QSPR) and the reported augmented multivariate image analysis applied to QSPR (aug-MIA-QSPR), the proposed approach is more simple, accurate and reliable. This study not only obtained the model with better stability and predictive ability for the BMF of organochlorine pollutants, but also provided another effective approach to QSPR research.
Decreased renal function increases the nighttime urine volume rate by carryover of salt excretion to the nighttime
Authors: Takezawa Kentaro , Kuribayashi Sohei , Okada Koichi , Sekii Yosuke , Inagaki Yusuke , Fukuhara Shinichiro , Kiuchi Hiroshi , Abe Toyofumi , Fujita Kazutoshi , Uemura Motohide , Imamura Ryoichi , Nonomura Norio
Published: March 2021

Purpose: To determine the pathophysiology of nocturnal polyuria associated with renal dysfunction.Methods: Patients who underwent laparoscopic nephrectomy were studied prospectively. The diurnal variation in urine volume, osmolality, and salt excretion were measured on preoperative day two and postoperative day seven. The factors associated with an increase in the nighttime urine volume rate with decreased renal function were evaluated by multiple linear regression analysis.Results: Forty-nine patients were included. The eGFR decreased from 73.3 ± 2.0 to 47.2 ± 1.6 mL/min/1.73 m2 (P < 0.01) and the nighttime urine volume rate increased from 40.6% ± 2.0% to 45.3% ± 1.5% (P = 0.04) with nephrectomy. The nighttime urine osmolality decreased from 273 ± 15 to 212 ± 10 mOsm/kg (P < 0.01) and the nighttime salt excretion rate increased from 38.7% ± 2.1% to 48.8% ± 1.7% (P < 0.01) with nephrectomy. Multiple linear regression analysis revealed that the increase in the nighttime urine volume rate was strongly affected by the increase in the nighttime salt excretion rate.Conclusion: A decrease in renal function causes an increase in the nighttime urine volume rate, mainly due to an increase in nighttime salt excretion.Trial registration number: UMIN000036760 (University Hospital Medical Information Network Clinical Trials Registry)Date of registration: From June 1st, 2019 to October 31th 2020
A Geriatrics-Focused Hospitalist Trauma Comanagement Program Improves Survival and Quality Measures for Older Adults: A Propensity Score-Matched Analysis
Authors: Zhang Nasen J. , Sinvani Liron , Leung Tung Ming , Qiu Michael , Meyer Cristy L. , Sharma Ankita , Kurian Linda M. , Bank Matthew A. , Kast Charles L.
Published: March 2021

Background: Given the increasing age and medical complexity of trauma patients, medical comanagement has been adopted as a strategy for high-risk patients. This study aimed to determine whether a geriatrics-focused hospitalist trauma comanagement program improves outcomes.Methods: A pre- and post-implementation study compared older adult trauma patients who were comanaged by a hospitalist with those prior to comanagement at a Level 1 trauma center. Criteria for comanagement included: age 65+, multiple comorbidities, and use of high-risk medications. Comanagement focused on geriatric trauma management guidelines. One-to-one propensity score matching (PSM) was performed based on age, gender, Injury Severity Score, Charlson comorbidity index, and initial admission to the intensive care unit (ICU). Outcomes included hospital mortality, length of stay (LOS), and orders for geriatrics-focused quality indicators. Differences were compared with the Wilcoxon Rank Sum test for continuous variables and chi- square or Fisher’s exact test for categorical variables.Results: From 792 control and 365 intervention patients, PSM resulted in 290 matched pairs. Three intervention group patients died compared to 14 in the control group (p=0.0068). Hospital LOS, 30-day readmission, ICU LOS, and ICU upgrades were not significantly different between groups. There was an overall trend toward improved geriatrics-focused quality indicators in the intervention group. Intervention group was less likely to be restrained (p=0.04), received earlier physical therapy (p=0.01), more doses of acetaminophen compared to control patients (p<0.0001), and more subcutaneous enoxaparin rather than heparin (p=0.0027).Discussion: Our main findings highlight the higher medical complexity and increased risks in older adult trauma patients, as well as the mortality reduction and adherence increase to geriatrics-focused quality indicators. Limitations of our study included use of a single center, the possibility of selection bias in analyzing historical data, and a low sample size, all of which may limit generalizability. Conclusions: Our study demonstrates that a geriatrics-focused hospitalist trauma comanagement program improves survival and quality of care.
Analysis of the extracorporeal anticoagulation effect of modified citrate infusion during continuous haemodialysis in critically ill patients
Authors: Guo Litao , Liu Yu
Published: March 2021

This study aimed to analyse the anticoagulation effect of different local infusion methods for citrate continuous haemodialysis in critically ill patients in order to identify a safe and effective citrate infusion method. Critically ill patients admitted to our hospital from April 2019 to December 2019 who underwent continuous renal replacement therapy (CRRT) using citrate for anticoagulation were divided into the conventional citrate infusion before the filter (conventional group) and citrate infusion group according to the different local citrate infusion methods (modified group). A total of 30 treatment sessions were performed for each group. the modified group patients were found to have longer mean treatment times(67.67 ± 18.69 vs 52.11 ± 24.26,p = 0.007), lower transmembrane pressures at the disconnection time from dialysis circuit(147.77 ± 66.85 vs 200.63 ± 118.66,p = 0.038), fewer citrate bag replacements(1.43 ± 0.50 vs 10.60 ± 3.19,p < 0.001), and steady ionised calcium at the venous end compared to the conventional group patients with statistically significant differences(0.35 ± 0.06 vs 0.40 ± 0.05,p = 0.006). The total calcium level was significantly higher in the conventional group patients than those of the other(2.29 ± 0.23 vs 2.19 ± 0.14,p = 0.038). Incidences of citrate accumulation and tubing coagulation were also marginally lower in the modified group. We infer that the modified local citrate infusion method can prolong the treatment time, reduce the nursing workload and the occurrence of citrate accumulation, resulting in safe and effective clinical outcome.
Prosocial Modeling Matters: The Association between Parent and Faculty Involvement in Fighting COVID-19 with Medical Students’ Career Commitment
Authors: Wang Dan , Ye Xiaoyang , Wu Hongbin
Published: March 2021

Background: Role models play an important role in enhancing students’ intention to pursue medical careers. While, as the two most influential role models for medical students, there is limited research to explore the different impacts between faculty and parents. This study investigated the association of different role model’s prosocial behavior of joining the fight against novel coronavirus disease 2019 (COVID-19) on medical students’ career commitment. We examined whether there are different effects and how these effects differ among different medical students.Method: A national-scale survey was conducted with 118,030 undergraduate students majoring in clinical medicine in mainland China. Questions were asked to collect information of participants in the battle of COVID-19, medical students’ determination of practicing medicine after graduation, as well as students’ socio-demographic characteristics. Chi-square tests and hierarchical regressions were performed to examine the effects of parent and faculty involvement on students’ career commitment.Results: The results showed that prosocial modeling during the COVID-19 pandemic in China is associated with students’ intention to pursue medical careers. The effect of faculty was greater than that of parents on medical students. Gender was related to the effects. And those who already determined to be the doctor before the pandemic were much more likely to persist in the medical profession.Conclusions: Our study provides more definitive answers to the issue of who has a greater effect on medical students’ career commitment between parents and faculty. Encouraging faculty to act as positive role models could help medical students increase the intention to become doctors.
Molecular Modeling and Virtual Screening of Molecular Inhibitors for Leptospiral Collagenase
Authors: Kumar Vikram , Srikaku Nagesh , Aathmanathan Veeranarayanan Surya , Satheeshkumar Padikara K , Madathiparambil Madanan Gopalakrishnan , Krishnan Muthukalingan , Tennyson Jebasingh
Published: March 2021

Collagenase is a virulence factor which facilitates the invasion of pathogenic Leptospira into the host. In the present study, the model of Leptopsiral collagenase was constructed by employing threading method with the crystal structure of collagenase G. Three ligand binding sites at N- terminus, catalytic site and C-terminus were predicted by Metapocket server. Among sixty seven inhibitors from the ChEBI and Zinc databases, Protohypericin is predicted as the best inhibitor since it binds at the catalytic site of Leptopsiral collagenase. Molecular dynamic simulation studies validated the stability of interaction between the active site of Leptospiral collagenase and Protohypericin. The docking and molecular simulation studies corroborated the potential of the ligand to curb leptospiral infection.
On-machine Measurement and Uncertainty Analysis for Semicircular Narrow Neck Thickness based on Ultra-precision Machine Tool
Authors: Jin Xin , Gao Ruilin , Li Chaojiang , Zheng Zhong peng , Zuo zhen
Published: March 2021

As flexible joint is a typical low-rigidity micro part, which have four narrow neck structures evenly distributed around its central axis, it is necessary to strictly control the dimensional accuracy of the narrow necks to improve the consistency of stiffness. However, the radius of the arc of the narrow necks is less than 2mm, and the thickness of thinnest part of the necks formed by two adjacent arcs is only tens of microns, which also has sub-micron accuracy requirement. These cross-scale dimensional characteristics and accuracy requirements give rise to extremely difficulty on the measuring process. In this paper, an on-machine measurement method for the semicircular narrow necks was presented and a measuring device was developed based on the comparative principle by making full use of the high linearity characteristic in the small measuring range of the sensor probes. Meanwhile, the on-machine measurement process based on ultra-precision machine tools was also introduced in details. The experiments results show that the uncertainty of the measurement method proposed is less than 0.2µm, and the repeatability is less than 0.1μm, which meet the measuring requirement of flexible joint. Furthermore, the effect of probe position, measurement force, environmental factor and the accuracy of the sensor on total measuring accuracy was analyzed, which could provide further evidences to improve the measuring accuracy. of micro-scale hybrid surface texture.
Visual Inspection with Acetic Acid (VIA) Positivity Among Female Sex Workers: a Cross-sectional Study Highlighting One-year Experiences in Early Detection of Pre-cancerous and Cancerous Cervical Lesions in Kampala, Uganda
Authors: Namale Gertrude , Mayanja Yunia , Kamacooko Onesmus , Bagiire Daniel , Ssali Agnes , Seeley Janet , Newton Robert , Kamali Anatoli
Published: March 2021

Background: Although cervical cancer is preventable, most women in sub-Saharan Africa (SSA) do not receive routine screening and few treatment options exist. Female Sex Workers (FSWs) are among the Ugandan female population at highest risk of acquiring sexually transmitted infections (STIs) including HIV and human papilloma viruses (HPV), the cause of cervical cancer. We report one-year experiences of visual inspection with acetic acid (VIA) positivity among FSWs in the early detection of pre-cancerous and cancerous cervical lesions in Kampala, Uganda.Methods: Between June 2014 and July 2015, we enrolled FSWs into a cross-sectional study at a research clinic. The women were screened using the VIA method (application of 3-5% acetic acid to the cervix). All VIA positive women were referred to a tertiary hospital for colposcopy, biopsy, and immediate treatment (if indicated) at the same visit according to national guidelines. Data on socio-demographic, sexual behaviour, sexual reproductive health and clinical characteristics were collected. We used logistic regression to identify factors associated with VIA positivity.Results: Of 842 women assessed for eligibility, 719 (85%) of median age 30 (IQR 26, 35) were screened, and 40 (6%) women were VIA positive. Of the 24 histology specimens analysed, 6 showed inflammation, only 1 showed cervical intraepithelial neoplasia (CIN) 1, 13 women showed CIN2/3, while 4 women already had invasive cervical cancer. The overall prevalence of HIV was 43%, of whom only 35% were receiving ART. In the age-adjusted analysis, VIA positivity was more likely among women who reported having >100 life-time partners (aOR=3.34, 95%CI: 1.38-8.12), and HIV positive women (aOR=4.55; 95%CI: 2.12 - 9.84).Conclusion: We found a relatively low proportion of VIA positivity in this population. The experience from our program implies that the VIA results are poorly reproducible even among a category of trained professional health workers. VIA positivity was more likely among women with a high number of sexual partners and HIV infection. Interventions for improving cervical cancer screening should be recommended as part of HIV care for FSWs to reduce the disease burden in this population.