bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermodynamic Basis of Brine Density on Pressure, Temperature, and Chemical Composition in Ultrahigh Pressure/High Temperature Environments
Authors: Rahman Shaikh M. , Sathuvalli Udaya B. , Suryanarayana P. V.
Published: December 2021

Temperature change and the pressure/volume/temperature (PVT) response of wellbore annular fluids are the primary variables that control annular pressure buildup in offshore wells. Though the physics of annular pressure buildup is well understood, there is some ambiguity in the PVT models of brines. While custom tests can be performed to determine the PVT response of brines, they are time-consuming and expensive. In this light, our paper presents a method to determine the density of brines from their chemical composition, as a function of pressure and temperature. It compares theoretical predictions with the results of tests on brines used in our industry and available test data from the oil and gas and other industries.

In 1987, Kemp and Thomas used the principles of chemical thermodynamics to develop equations for the density of brines as a function of pressure and temperature and their electrolytic actions. However, their paper contained two (inadvertent, and probably typographical) errors. One of the errors lay in the set of the Debye-Hückel parameters, and the other was contained in the coefficients of the series expansion for the infinite dilution molal volume. Furthermore, they (inadvertently) did not mention the role of a crucial parameter that accounts for the interaction between the ionic constituents of the salt. As a result, nearly a generation of engineers in our industry has been unable to reproduce their valuable results or apply their technically rigorous results to other brine chemistries.

In this paper, we return to the basic equations of chemical thermodynamics and the principles of stoichiometry and delineate the inadvertent errors that had crept into the Kemp and Thomas equations. We then present the rectified equations and reproduce their example with the corrected results. Further, we compare the predictions from the original Kemp and Thomas work with results from a leading chemical engineering model. Finally, we compare the results of theoretical models with test measurements from the laboratory and characterize the uncertainty inherent in each model. Thereby, we have rendered the Kemp and Thomas (1987) model useful to the well design community.
Time-Lapse Pulsed Neutron Well Logging in Oil Sands for Monitoring Steam Chamber Development
Authors: Kim Yonghwee , Kotov Alexandr , Chace David
Published: December 2021

Steam-assisted gravity drainage (SAGD) technology, although a relatively new oil recovery method, has already proved its value in economic development of heavy-oil sands in Western Canada. The SAGD process requires a lifetime monitoring of steam chamber growth to optimize reservoir development, improve oil recovery, and minimize environmental impact. Operators have widely used pulsed neutron well logs to monitor their life cycles of oil sand reservoirs. Time-lapse pulsed neutron logs acquired in observation wells enable operators to effectively track the growth of the steam chamber and identify the changes of formation fluid saturations. We present high-temperature pulsed neutron logging technology and an algorithm to quantify steam, heavy oil and water saturations in SAGD wells.

One of the major challenges in well logging operation is to withstand the thermal shock from the steam chamber. Reservoir temperature often varies abruptly, by as much as 250 degrees C in a very short interval, so the logging tool must be stable in drastic temperature variations. Well logging conditions such as a steam-filled wellbore, extra completion hardware and bad cement quality are challenging factors as well. Furthermore, formation fluid saturation analysis in Canadian oil sands is typically complex because the formation water salinity is relatively fresh but varies, clay properties are not homogeneous, and SAGD operations create conditions in which three-phase fluids coexist in the formation. These environmental conditions make it difficult to rely only on commonly used thermal neutron capture cross-section measurements (formation sigma).

In this paper, case study examples present the above-mentioned challenges and solutions to identify the multi-component formation fluids. The multi-detector pulsed neutron well logging instrument has been modified with a custom-designed heat flask to handle the extreme temperature variations in the SAGD environment. This heat-flask equipped instrument ensures a stable data acquisition in the presence of rapid and extreme temperature variation and enables a prolonged and time-efficient operation through effective heat management. For saturation analysis, we demonstrate an advanced algorithm to quantify three fluid components using a combination of gamma ray ratio and carbon/oxygen (C/O) measurements.
Gas Well Deliquification in the Presence of High Content of Condensate: From Laboratory to Field Test
Authors: He Xiujuan , Lei Wei , Xu Xin , Xu Jian , Qiu Jun , Dai Wei , Cui Leyu , Ma Junwei , Shen Zhiqin , Li Yingcheng
Published: December 2021

Two foaming formulations, an amphoteric surfactant (noted as Fam) and a blend of anionic-cationic-amphoteric surfactants (noted as Facam) have been prepared and tested at lab and in field in the presence of high content of condensate (60 vol% on average). Foam height with Facam are close to those with Fam. Although Fam has better foam stability without condensate, the half-life of the foam (t1/2) decreases by 50% in presence of condensate. Foam generated by Facam shows better oil resistance performance due to negative spreading coefficient (S). Liquid unloading efficiency with Facam are close to those with Fam at lab. Nevertheless in field application, Facam is more efficient than Fam for the deliquification in the gas well. The depth of gas well is 2126 m. Foaming formulations were injected respectively from casing pipe with injection amount of 1-2kg/day. The pressure difference between casing and tubing pipes (ΔPc-t) decreased from 1.0 MPa to 0.28 MPa, and the decline of gas production was slowed down after the injection of Facam in the gas well. As a contrast, both theΔPc-t and decline rate of gas production were increased with Fam. Foam resistance to condensate is a factor, while emulsion viscosity is inferred to be another crucial factor for the performance of formulations in the deliquification process.
Integration of Post-Fracturing Spectral Noise Log, Temperature Modeling, and Production Log Diagnoses Water Production and Resolves Uncertainties in Openhole Multistage Fracturing
Authors: Asif Adnan Bin , Hansen Jon , Khan AbdulMuqtadir , Sheshtawy Mohamed
Published: December 2021

Hydrocarbon development from tight gas sandstone reservoirs is revolutionizing the current oil and gas market. The most effective development strategy for ultralow- to low-permeability reservoirs involves multistage fracturing. A cemented casing or liner completed with the plug-and-perf method allows nearly full control of fracture initiation depth. In uncemented completions equipped with fracturing sleeves and packers, clearly identifying the fracture initiation points is difficult due to lack of visibility behind the completion and long openhole intervals between packers. Also, the number of fractures initiated in each treatment is uncertain.

A lateral was completed with access to 3,190 ft of openhole section across five fracturing stages in a high-temperature and high-pressure tight-gas interval. All stages were successfully stimulated, fracture cleanup flowback was conducted, and entry ports were milled out. A high-definition spectral noise log (SNL) was then conducted along with numerical temperature modeling. Additional logging was done with a set of conventional multiphase sensors. A multi-array production log suite was also performed. Finally, the bottom four stages were isolated with a high-temperature isolation plug based on the integrated diagnosis.

The SNL helped to analyze the isolation packer integrity behind the liner. The initiation of multiple fractures was observed, with as many as nine fractures seen in a single-stage interval. A correlation was found between the openhole interval length and the number of fractures. A correlation of fracture gradient (FG) and initiation depths was made for the lateral in a strike-slip fault regime. The fractures were initiated at depths with low calculated FG, confirming the conventional understanding and increasing confidence in rock property calculations from openhole log data. SNL and temperature modeling aided quantitative assessment of flowing fractures and stagewise production behind the liner. Multi-array production logging results quantified the flow and flow profile inside the horizontal liner. The production flow assessments from both techniques were in good agreement. The integration of several datasets was conducted in a single run, which provided a comprehensive understanding of well completion and production. High water producing intervals were isolated. Downstream separator setup after the isolation showed a water cut reduction by 95%.

The integration of the post-fracturing logs with the openhole logs and fracturing data is unique. The high-resolution SNL provided valuable insight on fracture initiation points and the integrity of completion packers. Fracturing efficiency, compared to the proppant placed, provides treatment optimization for similar completions in the future.
Optimizing Seawater Based Fracture Fluids Rheology Utilizing Chelating Agents
Authors: Othman Amro , Aljawad Murtada Saleh , Kamal Muhammad Shahzad , Mahmoud Mohamed , Patil Shirish
Published: December 2021

Due to the scarcity and high cost of freshwater, especially in the Gulf region, utilization of seawater as a fracturing fluid gained noticeable interest. However, seawater contains high total dissolved solids (TDS) that may damage the formation and degrade the performance of the fracturing fluids. Numerous additives are required to reduce the damaging effect and improve the viscosity resulting in an expensive and non-eco-friendly fracturing fluid system. Chelating agents, which are environmentally benign, are proposed in this study as the replacement of many additives for seawater fracturing fluids.

This study focuses on optimizing chelating agents to achieve high viscosity employing the standard industry rheometers. Carboxymethyl Hydroxypropyl Guar Gum (CMHPG) polymer, which is effective in hydraulic fracturing, was used in this research with 0.5 and 1.0 wt% in deionized water (DW) as well as seawater (SW). It was first tested as a standalone additive at different conditions to provide a benchmark then combined with different concentrations, and pH level chelating agents. In this study the hydration test was conducted through different conditions.

It was observed that CMHPG, when tested as a standalone additive, provided slightly higher viscosity in SW compared to DW. Also, increasing polymer concentration from 0.5 to 1.0 wt% provided three folds of viscosity. The viscosity did not show time dependence behavior at room temperature for the aforementioned experiments where all hydration tests were run at 511 1/s shear rate. Temperature, however, had a significant impact on both viscosity magnitude and behavior. At 70 °C, the fluid viscosity increased with time where low viscosity was achieved early on but kept increasing with shearing time. Similarly, high pH chelating agents provided time dependant viscosity behavior when mixed with CMHPG. This behavior is important as low viscosity is favorable during pumping but high viscosity when the fluids hit the formation.

The study investigates the possibility of utilizing chelating agents with seawater to replace numerous additives. It acts as a crosslinker at early shearing times, where a gradual increase in viscosity was observed and a breaker in the reservoir harsh conditions. It also captures the divalent ions that are common in seawater, which replaces the need for scale inhibitors. The viscosity increase behavior can be controlled by adjusting the pH level, which could be desirable during operations.
Switched Reluctance Motor for Electric Submersible Pump
Authors: Adams Robert , Xiao Jinjiang , Cross Michael , Deffenbaugh Max
Published: December 2021

Switched reluctance motors may be advantageous when used as the primary motor for an electric submersible pump system. They are less susceptible to jamming failures due to their high starting torque and ability to reverse direction. Driving these motors requires well-timed pulse waveforms and precise control of the motor based on its rotational position. It is demonstrated that the pulses required to drive switched reluctance motors can still be applied over along cable lengths. Additionally, the current at the surface can be used to monitor and control the operation of the motor downhole, even with long cable lengths separating the surface power source and downhole motor.
Applied Transfer Learning for Production Forecasting in Shale Reservoirs
Authors: Odi Uchenna , Ayeni Kola , Alsulaiman Nouf , Reddy Karri , Ball Kathy , Basri Mustafa , Temizel Cenk
Published: December 2021

There are documented cases of machine learning being applied to different segments of the oil and gas industry with different levels of success. These successes have not been readily transferred to production forecasting for unconventional oil and gas reservoirs because of sparsity of production data at the early stage of production. Sparsity of unconventional production data is a challenge, but transfer learning can mitigate this challenge.

Application of machine learning for production forecasting is challenging in areas with insufficient data. Transfer learning makes it possible to carry over the information gathered from well-established areas with rich data to areas with relatively limited data. This study outlines the background theory along with the application of transfer learning in unconventionals to aid in production forecasting. Similarity metrics are utilized in finding candidates for transfer learning by using key drivers for reservoir performance. Key drivers include similar reservoir mechanisms and subsurface structures. After training the model on a related field with rich data, most of the primary parameters learned and stored in a representative machine or deep learning model can be re-used in a transfer learning manner. By employing the already learned basic features, models with sparse data have been enriched by using transfer learning. The approach has been outlined in a stepwise manner with details.

With the help of the insights transferred from related sites with rich data, the uncertainty in production forecasting has decreased, and the accuracy of the predictions increased. As a result, the details of selecting a related site to be used for transfer learning along with the challenges and steps in achieving the forecasts have been outlined in detail.

There are limited studies in oil and gas literature on transfer learning for oil and gas reservoirs. If applied with care, it is a powerful method for increasing the success of models with sparse data. This study uses transfer learning to encapsulate the basics of the substructure of a well-known area and uses this information to empower the model. This study investigates the application to unconventional shale reservoirs, which have limited studies on transfer learning.
Integrating Deep Learning and Physics-Based Models for Improved Production Prediction in Unconventional Reservoirs
Authors: Mohd Razak Syamil , Cornelio Jodel , Jahandideh Atefeh , Jafarpour Behnam , Cho Young , Liu Hui-Hai , Vaidya Ravimadhav
Published: December 2021

The physics of fluid flow and transport processes in hydraulically fractured unconventional reservoirs are not well understood. As a result, the predicted production behavior using conventional simulation often does not agree with the observed field performance data. The discrepancy is caused by potential errors in the simulation model and the physical processes that take place in complex fractured rocks subjected to hydraulic fracturing. Additionally, other field data such as well logs and drilling parameters containing important information about reservoir condition and reservoir characteristics are not conveniently integrated into existing simulation models. In this paper, we discuss the development of a deep learning model to learn the errors in simulation-based performance prediction in unconventional reservoirs. Once trained, the model is expected to forecast the performance response of a well by augmenting physics-based predictions with the learned prediction errors from the deep learning model. To learn the discrepancy between simulated and observed production data, a simulation dataset is generated by using formation, completion, and fluid properties as input to an imperfect physics-based simulation model. The difference between the resulting simulated responses and observed field data, together with collected field data (i.e. well logs, drilling parameters), is then used to train a deep learning model to learn the prediction errors of the imperfect physical model. Deep convolutional autoencoder architectures are used to map the simulated and observed production responses into a low-dimensional manifold, where a regression model is trained to learn the mapping between collected field data and the simulated data in the latent space. The proposed method leverages deep learning models to account for prediction errors originating from potentially missing physical phenomena, simulation inputs, and reservoir description. We illustrate our approach using a case study from the Bakken Play in North Dakota.
Single Trip Deployment of Multistage Completion Liners Through the Use of Interventionless Flotation Collars
Authors: Tait William , Munawar Mohammed
Published: December 2021

In difficult wellbores, the traditional method for deploying liners was to run drillpipe. The case studies discussed in this paper detail an alternative method to deploy liners in a single trip on the tieback string so the operator can reduce the overall costs of deployment. Previously, this was not often practical because the tieback string weight could not overcome the wellbore friction in horizontal applications.

In each case, a flotation collar is required to ensure there is enough hookload for the deployment of the liner system. The flotation collars used are an interventionless design using a tempered glass barrier that shatters at a predetermined applied pressure. The glass debris is between 5 and 10 mm in diameter and can be easily circulated through the well without damaging downhole components. This is done commonly on a cemented liner and cemented monobore installations, but more rarely with openhole multistage completions. The authors of this paper have overseen thousands of cemented applications of this technology in Western Canada, the US onshore, Latin America, and the Middle East. For openhole multistage completions, the initial installation typically requires a ball drop activation tool at the bottom of the well to set the hydraulically activated equipment above.

The effects of circulating the glass debris through one specific style of activation tool were investigated. Activation tools typically have a limited flow area and could prematurely close if the glass debris accumulates. Premature closing of the tool would leave drilling fluids in contact with the reservoir, potentially harming production. The testing was successfully completed, and the activation tool showed no signs of loading. This resulted in a full-scale trial in the field, where a 52-stage, openhole multistage fracturing liner was deployed using this technology.

Through close collaboration with the operator, an acceptable procedure was established to safely circulate the glass debris and further limit the risk of prematurely closing the activation tool. This paper discusses the openhole and cemented multistage fracturing completion deployment challenges, laboratory testing, and field qualification trials for the single trip deployed system. It also highlights operational procedures and best practices when deploying the system in this fashion.
Production Forecasting with the Interwell Interference by Integrating Graph Convolutional and Long Short-Term Memory Neural Network
Authors: Du Enda , Liu Yuetian , Cheng Ziyan , Xue Liang , Ma Jing , He Xuan
Published: December 2021

Accurate production forecasting is an essential task and accompanies the entire process of reservoir development. With the limitation of prediction principles and processes, the traditional approaches are difficult to make rapid predictions. With the development of artificial intelligence, the data-driven model provides an alternative approach for production forecasting. To fully take the impact of interwell interference on production into account, this paper proposes a deep learning-based hybrid model (GCN-LSTM), where graph convolutional network (GCN) is used to capture complicated spatial patterns between each well, and long short-term memory (LSTM) neural network is adopted to extract intricate temporal correlations from historical production data. To implement the proposed model more efficiently, two data preprocessing procedures are performed: Outliers in the data set are removed by using a box plot visualization, and measurement noise is reduced by a wavelet transform. The robustness and applicability of the proposed model are evaluated in two scenarios of different data types with the root mean square error (RMSE), the mean absolute error (MAE), and the mean absolute percentage error (MAPE). The results show that the proposed model can effectively capture spatial and temporal correlations to make a rapid and accurate oil production forecast.
Improving Family Health Climate, Effect of Role Modeling and Maternal Support in Female Student
Authors: Ostovarfar Jeyran , Kaveh Mohammad Hossein , Ghahramani Leila , Karimi Masoud , Asadollahi Abdolrahim , Zare Razie
Published: December 2021

Introduction: Girls can use their mothers emotional, informational and behavioral support to perform healthy behaviors due to their constant access to their mothers. This study aimed to evaluate the effect of role modeling and maternal support in the family to improve healthy behaviors and perceived Family Health Climate (FHC) in female students.Methods: In this quasi-experimental study 261 female students (133 in intervention group and 128 in control group) and 223 mothers (109 intervention and 114 control) were selected, using cluster multi-stages sampling method and entered the study. Participants completed the FHC scale at three stages (Before intervention, immediately after the intervention and two month after intervention). A training programme which comprised 12 sessions for students and 6 sessions for their mothers using collaborative learning techniques and printed materials was conducted with the experimental group. Data were analyzed using SPSS20 via chi-square test, independent t-test, and Repeated Measures ANOVA at significance level of 0.05.Results: Before the intervention, there was no significant difference between demographic variables and the score of FHC scale in both groups (p<0.05). Immediately and two months after the intervention, the experimental group (female students and their mothers) showed a significant increase in dimensions of FHC including FHC-NU and FHC-PA (their subscales) compared to the control group (p<0.05).Conclusions: Educating and informing mothers about their role model defects for their children, especially girls, can make them more aware of health-oriented behaviors towards their children. Such findings reinforced the importance of focusing on actions to encourage a healthy lifestyle (healthy diet and physical activity) in students with a focus on role modeling and parental support, especially mothers.
Determinants of Pelvic Organ Prolapse at Public Hospitals in Hawassa City, Southern Ethiopia, 2020: Unmatched Case Control Study
Authors: Dora Bezabih Terefe , Kassa Zemenu Yohannes , Hadra Nebiha , Tsigie Bamlaku Birie , Esayas Hawi Leul
Published: December 2021

Introduction: Even though the Pelvic organ prolapse (POP) is outstanding gynecologic problem, most private and asymptomatic nature of the illness makes it the “hidden epidemic.” The aim of this study was to identify the determinants of POP. Methods: Facility based unmatched case control study was conducted from June 15 to September 10, 2020. All cases diagnosed with POP were enrolled in the study by using consecutive random sampling method by assuming that patient flow by itself is random until the required sample size was obtained. Then 1:2 cases to control ratio was applied. A structured interviewer-administered questionnaire and chart review for type and degree of prolapse was used. Epi-data and SPSS were used for analysis. Chi square test and binary and multivariable logistic regression analysis was employed. Multicolinearity was checked. Result: On multivariate logistic regression, heavy usual work load(AOR=2.3, CI(1.066-4.951), number of pregnancy ≥ 5(AOR=3.911, CI(1.108-13.802), birth space of <2 years(AOR=2.88, CI(1.146-7.232), history of fundal pressure (AOR=5.312, CI(2.366-11.927) and history of induced labor (AOR=4.436, CI(2.07-9.505) were significantly associated with POP with P value <0.05 and 95% CI after adjusting for potential confounders.Conclusion: Heavy usual work load, having pregnancy greater than five, short birth space, history of induced labor, and history of fundal pressure are independent predictors of pelvic organ prolapse. Hence the responsible body and obstetric care providers should counsel the women about child spacing. The obstetric care providers also avoid fundal pressure and the hospital officials set a law to ban fundal pressure during labor.
Photocatalytic Remediation of Methylene Blue and Antibacterial Activity Study Using Schiff Base - Cu Complexes
Authors: H Fathima Fasna P , Sasi Sreesha , K Bindu Sharmila T , S Julie Chandra C , Antony Jolly V , Raman Vidya
Published: December 2021

Photocatalytic degradation of organic dyes under visible light and ultraviolet radiation is an efficient strategy for effluent treatment. This work describes the design of novel Cu(II) complexes using the ligand N'-(3-hydroxy-4-methoxybenzylidene)nicotinohydrazide and their application in the photocatalytic degradation of the organic dye, methylene blue (MB). The photocatalytic degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2> 0.95), making them useful as simple and low-cost organic dye degradation agents. The antibacterial screening studies of the ligand and the Cu(II) complexes by disc diffusion method show the systems to exhibit activity against Escherichia coli (gram negative) and Bacillus circulans (gram positive).
Anaerobic Co-Digestion of Food Waste and Thermal Pretreated Waste Activated Sludge: Synergetic Effect and Energy Assessment
Authors: Zhang Jian , Gan Peng , Wang Ru-yi , Xie Tian , Liu Yang , Zong Yi-feng , Wei Yan-ling
Published: December 2021

Thermal pretreatment was an effective method to improve the anaerobic digestion of waste activated sludge. However its application in China was still hindered by the high energy demand. In order to balance the energy consumption of sludge thermal pretreatment integrated with anaerobic digestion, food waste was introduced as co-substrate to achieve an energy self-sustainable sludge treatment system. Anaerobic biodegradability test was performed using thermal pretreated sludge and food waste in order to clarify the kinetics and mechanism of co-digestion, especially the synergetic effect on specific methane yield. The prominent synergetic effect was an initial acceleration of cumulative methane production by 20.7- 23.8% observed during the first 15 days, and the cumulative methane production of feedstock can be calculated proportionately from its composition. Between the evaluated models, modified Gompertz model presented a better agreement of the experimental results and it was able to describe the synergetic effect, assessed by the relative deviation between theoretical estimation and the experimental results of co-digestion tests. This feature made modified Gompertz model a suitable tool for methane production prediction of mono- and co-digestion. Energy assessment shown that co-digestion with food waste was a sustainable solution to maintain the integration of thermal pretreatment and anaerobic digestion energy neutral or even positive. Besides, the performance of sludge dewatering was a crucial factor for the energy balance.
Factors Associated with a Malaria Outbreak at Tongogara Refugee Camp in Chipinge District, Zimbabwe, 2021: A Case-Control Study
Authors: Takarinda Kudzai Patience , Nyadundu Simon , Govha Emmanuel , Chadambuka Addmore , Gombe Notion Tafara , Juru Tsitsi Patience , Tshimanga Mufuta
Published: December 2021

Background: Malaria is a leading cause of morbidity and mortality among forcibly displaced populations including refugees, approximately two-thirds of whom reside in malaria endemic regions. Data from the rapid disease notification system (RDNS) reports for Manicaland Province in Zimbabwe showed that despite implementation of malaria control initiatives, there was an increase in number of malaria cases above action thresholds at Tongogara Refugee Camp in Chipinge District during weeks 12-14. We investigated the malaria outbreak describing the outbreak by person, place and time, assessing malaria emergency preparedness and response and appropriateness of case management. We also determined the factors associated with contracting malaria to enable the formulation of appropriate interventions, establish control and prevent future malaria outbreaks among this vulnerable population.Methods: We conducted a 1:1 unmatched case control study involving 80 cases and 80 controls using interviewer-administered questionnaires at household level. Data was entered using Epi Data version 3.1 and analyzed using Epi InfoTM version 7.2.4 to generate medians, proportions, odds ratios and their 95% confidence intervals.Results: Malaria cases were distributed throughout the 10 residential sections within Tongogara Refugee Camp, the majority being from section 7, 28/80 (35%). Despite constituting 11% of the total population, Mozambican nationals accounted for 36/80 (45%) cases. Males constituted 47/80 (59%) among cases versus controls 43/80 (54%), p=0.524. Median age for cases was also lower compared to controls; 15 years [Interquartile range (IQR), 9-26] versus 17 years (IQR, 10-30). Several natural and manmade potential vector breeding sites were observed around the camp. Risk factors associated with contracting malaria were engaging in outdoor activities at night [AOR 4.26 (95% CI, 1.43-12.68)], wearing clothes that do not cover the whole body [AOR=2.74 (95% CI 1.04-7.22) while sleeping in a refugee housing unit reduced the risk of contracting malaria [AOR=0.18 (CI, 0.06-0.55)]. Conclusions: The malaria outbreak at Tongogara Refugee Camp reemphasizes the role of behavioral factors in malaria transmission. We recommend intensified health education to address human behaviors that expose residents to malaria and habitat modification with larviciding to eliminate mosquito breeding sites.
Photonic Remote Microwave Frequency Measurement With a Tunable Measurement Range Based on Dispersion Compensation Technology
Authors: Meng Qingqing , Zhu Zihang , Lin Tao , Li He , Wang Guodong , Huang Lanfeng , Li Xuan , Yu Longqiang , Zhao Shanghong
Published: December 2021

In this paper, a novel and efficient photonic-assisted remote frequency measurement (RFM) system with a significantly simplified structure and flexible operation range is proposed. By simply changing the dispersion coefficient or length of the dispersion medium in the central station (CS), the microwave frequency measurement range in the remote antenna unit (RAU) can be tuned. In this system, the RAU and the CS is separated to ensure the concealment and safety of the signal processing unit. The measurement range of the RFM system can be tuned easily during the measurement process without system reconstruction, and different RAUs located at different places can be controlled to work at the same measurement range. The simulation results show that a frequency measurement over the high frequency range (>18 GHz) can be achieved with a measurement error better than ±0.2 GHz. Noteworthy, the impact of the non-ideal factors such as bias drift, intensity noise, phase noise, the equivalent deviation of the polarization beam splitter (PBS), and the dispersion value of the single mode fiber (SMF) is also discussed. It has been proved that they have little influence on the system performance over the high frequency range.
Utility of Cell-Free DNA from Bronchoalveolar Lavage Fluids Using Next Generation Sequencing in Predicting Malignant Solitary Pulmonary Nodules
Authors: Qi Jia-Chao , Lin Li , Zhao Zhiwei , Liao Liping , Lin Yixuan , Wang Tiezhu , Hu Miaofen , Wu Zhi , Ou Yangwu , Cai Zhiming , Ye Yuming , Wu Qiyin , Xu Qiaozhen , Zhang Weiliang , Huang Wensen , Li Hao
Published: December 2021

Purpose: To explore the utility of cell-free DNA (cfDNA) from bronchoalveolar lavage fluids (BALF) using next generation sequencing (NGS) in differentiating malignant tumors from benign solitary pulmonary nodule (SPN).Methods: Between January 1st 2019 and January 1st 2021, 40 subjects undergoing computed tomography (CT) examination who were diagnosed with SPN, were prospectively enrolled at Zhangzhou Affiliated Hospital of Fujian Medical University (Zhangzhou, Fujian, China). And pathological diagnosis were finally confirmed from tissue specimens obtained by surgical resection. For each patient, the mutations of gene were analysed using NGS in both extraction of cfDNA isolated from BALF and tissue. Results: Of 40 patients, 55% of them were diagnosed with lung adenocarcinoma, 20% with benign nodules, and 10% with small cell carcinoma. And patients with squamous carcinoma, adenosquamous carcinoma or large cell neuroendocrine carcinoma account for 5%, respectively. And 62.5% of malignant SPN (10/16) had at least one alteration. The most common alterations were TP53 (31.25%), followed by EGFR (18.75%), KRAS (12.5%), PIK3CA (6.25%), ERBB2 (6.25%), ALK (6.25%) and ROS1 (6.25%). Besides, there are some differences shown in the heatmap of gene mutation in the histologic sample. And there was a colse correlation between the mutations found in the tissue and BALF. For all 40 patients, the sensitivity, specificity, and concordance of BALF in predicting malignant nodules were 68.8%, 100%, and 75%, respectively. Conclusions: By NGS, tumor-specific mutations of cfDNA from BALF may be benefical to predicting malignant SPN, which may be taken into consideration for personalized cancer diagnosis.
A Discussion on Sea Level Rise, Rate Ad Acceleration. Venice as a Case Study
Authors: Camuffo Dario
Published: December 2021

The paper discusses the equations used to represent the sea level rise, and in particular the second-order polynomial, generally preferred because its second-order coefficient is related to acceleration. The long series of the sea level rise in Venice offers a particularly useful case study from 1350 to 2016, because it may be equally represented, at the same level of explained variance, by an exponential or a quadratic best-fit equation. The first-order and the second-order derivatives respectively represent the rate and the acceleration of sea level rise. The derivatives obtained from the second-order polynomial representation generate a linear rate and a constant acceleration, while those derived from an exponential preserve the exponential character. The two rates (i.e. from the quadratic and the exponential equations), and the two accelerations are characterized by different equations and different plots, but their average values are the same. The second-order polynomial with constant acceleration is in line with a climate with constant forcing factors; the exponential with a dynamic condition with increasing forcing factors and acceleration. Mathematical formulae and physical consequences are discussed in the framework of different scenarios. Finally, the trend-forecast extrapolation is discussed and applied to the case study of Venice. It is shown that, in the most optimistic assumption of forcing increasing at unchanged rate, the sea level in Venice will rise by 33.8 ± 4 cm over this century, that may be compared to the 31 cm of the similar, most optimistic prediction made by IPCC for business-as-usual.
16S rRNA Gene Sequencing Reveals Altered Composition of Gut Microbiota in Postoperative Individuals With Renal Stones
Authors: Deng Qiong , Wang Zhu , Wang Jieyan , Zhang Jianwen , Zhang Ying , Zhang Lirong , Liang Hui
Published: December 2021

BackgroundRenal stones are a common urological disease with high prevalence and recurrence rates. Characterizing gut microbiome profiles of first-onset renal calculi patients, both before and after surgery, may provide valuable insights and identify potential biomarkers for the disease. MethodsWe explored the associations between the gut microbiome and renal stone formation using 16S ribosomal RNA (rRNA) gene sequencing. In brief, 20 patients were recruited, and information on health and eating habits within the previous 1-3 months was collected upon admission.ResultsA total of 493 OTUs were detected in 40 specimens, with an average of 67,888 ± 827 reads per sample. The results of OUT-based PLS-DA analysis showed significant differences between RS1 and RS2 groups, with a significantly higher level of OTU7 in the RS2 group. Taxonomy‑based comparisons of the gut microbiome showed differences in the flora composition, with the prevalence of Enterobacteriales, Enterobacteriaceae, Gammaproteobacteria, and Escherichia being higher in the RS2 group and the prevalence of Pseudomonadaceae, Pseudomonadales, and Pseudomonas being higher in the RS1 group.ConclusionsThese data strongly suggest that the gut microbiome affects kidney stone formation, and these findings may provide new insights for the prevention, diagnosis, and treatment of renal stones.
Dynamic Responses of Multidiameter-class Fine Roots at Different Soil Depths to Thinning Measures in a Secondary Forest in China
Authors: Pang Yue , Tian Jing , Wang Dexiang
Published: December 2021

Background: Fine roots make critical contributions to carbon stocks and terrestrial productivity, and multidiameter-class fine roots exhibit functional heterogeneity. However, the dynamic characteristics of multidiameter-class fine roots at different soil depths following thinning disturbances are poorly understood. We investigated the biomass, production, mortality and turnover rate of < 0.5 mm, 0.5–1 mm and 1–2 mm fine roots at 0-20 cm, 20-40 cm and 40-60 cm soil depths under five thinning intensities (0%, 15%, 30%, 45%, and 60%) in a secondary forest in the Qinling Mountains. Results: The biomass, production and turnover rate of < 0.5 mm fine roots fluctuated with increasing thinning intensity, while 0.5-1 mm and 1-2 mm fine root biomass significantly decreased. Thinning measures had no effects on fine root necromass (except for T4) or mortality. The fine root dynamic characteristics in deeper soils were more sensitive to thinning measures. Principal component analysis results show that increased < 0.5 mm fine root biomass and production resulted from increased shrub and herb diversity and biomass and decreased soil nutrient availability, stand volume and litter biomass, whereas 0.5-1 mm and 1-2 mm fine root biomass showed the opposite trends and change mechanisms. Conclusions: Our results provide evidence of the positive effect of thinning on very fine root (< 0.5 mm) biomass and production and the negative effect on thicker fine roots (0.5-1, 1-2 mm) or all fine root (< 2 mm) biomass. From the perspective of fine root biomass and productivity, T2 (30%) is recommended for use in secondary forests of the Qinling Mountains. Moreover, our results suggest that thinning practices have varied effects on the dynamic characteristics of multidiameter-class fine roots.
The Differences of the Acromiohumeral Interval Between Supine and Upright Radiographs of the Shoulder
Authors: Sanguanjit Prakasit , Apivatgaroon Adinun , Boonsun Phanuwat , Srimongkolpi Surasak , C้hernchujit Bancha
Published: December 2021

Background: Acromiohumeral interval (AHI) is a measurement method to determine the superior migration of the humeral head in patients with rotator cuff tears.Hypothesis/Purpose: The purpose of this study was to compare the AHI measurement in supine shoulder and upright shoulder radiographs, as well as magnetic resonance imaging (MRI), as well as to report the sensitivity, specificity, and accuracy in detecting full thickness rotator cuff tears.Study Design: Diagnostic study.Methods: From July 2020 to May 2021, evaluation of 86 shoulder radiographs in both supine & upright Grashey views compared with the MRI of the affected shoulder. Measurements of the AHI obtained from both radiographs and MRIs was determined by two independent orthopaedic surgeons. The intraclass correlation of the AHI measurement was tested. The difference between the AHI in each view was determined.Result: The 86 shoulders were divided into 3 groups that included; 1) non-full thickness tear (50%), 2) full thickness (FT) tear 3 cm (33.7%), and 3) FT tear > 3 cm (16.3%). The mean difference of AHI noted was significantly lower in the supine radiographs than with the upright (1.34-1.37 mm.). The mean difference of the AHI was significantly lower in the MRI than the upright (1.62-1.87 mm.). AHI obtained from the supine radiographs and MRI had no significant differences. The area under the curve (AUC) of the upright and supine AHI in the diagnosis of the FT tears were at 0.649 and 0.642 accuracy. Upright AHI 7.09 mm. had 27.9% sensitivity and 100% specificity in diagnosing FT tears with 64% accuracy (p<0.001). The upright AHI cut off value of 9.52 mm. had 60.5% sensitivity, 67.4% specificity, and 64% accuracy (p=0.01). The supine AHI 6.56 mm. had 32.6% sensitivity, 100.0% specificity, and 66.3% accuracy (p<0.01). Supine AHI cut off value of 7.42 mm. had 41.9% sensitivity, 86.0% specificity, and 64.0% accuracy (p=0.004). The inter- and intra-rater reliability of AHI measurement in 3 views were of substantial to almost perfect agreement (0.668-0.824).Conclusion: The AHI in supine radiographs were significantly lower than upright shoulder radiographs in all groups as divided by severity of the rotator cuff tear and was comparable with the MRI. For AHI ≤ 7 mm. in upright shoulder radiographs remains as a good diagnostic test of full thickness rotator cuff tears, while this value was not relevant for use as the cut point in the supine radiographs and MRI shoulders.Level of evidence: Level III; Diagnostic studyClinical Relevance: The AHI measurement in supine and upright radiographs are reliable and reproducible. The AHI ≤ 7 mm. in upright shoulder radiographs remains as a good diagnostic test of full thickness rotator cuff tears, while this value was not relevant for use as the cut point in the supine radiographs and MRI shoulders.
Persistent Airflow Obstruction: A Marker of a Severe Asthma Cohort – Inflammatory, Functional and Pathological Features
Authors: Carvalho-Pinto Regina Maria , Athanazio Rodrigo Abensur , Ferreira Diogenes Seraphin , Mauad Thais , Dolhnikoff Marisa , Rached Samia , Fernandes Frederico Leon Arrabal , Rabe Klaus F , Cukier Alberto , Stelmach Rafael
Published: December 2021

In our previous severe asthma cohort, 82% had fixed obstruction. Although they had greater airway smooth muscle area with decreased periostin, inflammation and remodeling weren’t associated with symptom control. High-resolution computed tomography (HRCT) and measures of small airways could be important tools for exploring asthma severity. Our aim was to describe characteristics associated to airflow obstruction in our non-controlled severe asthmatics according to obstruction profile. Persistent obstruction subgroups were also evaluated comparing disease severity. Methods: Patients were evaluated using asthma control questionnaire, induced sputum, spirometry, plethysmography, and Single Breath N2 washout test, at baseline, after oral corticosteroid (OC) and at the end of the treatment. They also underwent thorax HRCT and bronchoscopy with endobronchial biopsy.Results: Sixty-two were included and 77.4% classified as having persistent obstruction; 75% and 25% with moderate and severe obstruction, respectively. Pulmonary function values (FEV1) improved in both subgroups, except in severe. Patients with bronchial thickening, according to RB1 WA% and pi10, had significantly higher airway smooth muscle area.Conclusion: Patients with severe obstruction had greater lung function impairment, no response to OC or bronchodilator. This could be explained by airway remodeling characterized by higher airway smooth muscle area and bronchial thickness assessed by thorax HRCT.
Non-directed highly para-selective C-H functionalization of TIPS-protected phenols promoted by a proton shuttle
Authors: Geng Jingyao , Fang Zhang , Tu Guangliang , Zhao Yingsheng
Published: December 2021

Palladium-catalyzed non-directed C-H functionalization provides an efficient approach for direct functionalization of arenes, but it usually suffers from poor site selectivity, limiting its wide application. Herein, it is reported for the first time that the proton shuttle of 3,5-dimethyladamantane-1-carboxylic acid (1-DMAdCO2H) can affect the site selectivity during the C-H activation step in palladium-catalyzed non-directed C-H functionalization, leading to highly para-selective C-H olefination of TIPS-protected phenols. This transformation displayed good generality in realizing various other para-selective C-H functionalization reactions such as hydroxylation, halogenation, and allylation reactions. A wide variety of phenol derivatives including bioactive molecules of triclosan, thymol, and propofol, were compatible substrates, leading to the corresponding para-selective products in moderate to good yields. A preliminary mechanism study revealed that the spatial repulsion factor between proton shuttle and bulky protecting group resulted in the selective C-H activation at the less sterically hindered para-position. This new model non-directed para-selective C-H functionalization can provide a straightforward route for remote site-selective C-H activations.
New Physics II: Spin Picture, Particle Structure, and Fundamental Interactions
Authors: Kang China
Published: December 2021

Experimental data sometimes fails to render the expected truth, such as high-speed bullets smashing into pieces on a water surface cannot verify the water’s hardness. By re-examining the essence underneath quantum phenomena and analyzing their relevance to universal classical theory, this study has thoroughly revealed the classical counterpart of spin. Subsequently, the equivalence between spin angular momentum (of energy or charge) and vorticity flux (of energy or charge) has also been unveiled, thus intuitively clarifying many abstruse physical concepts, like spin magnetic moment, virtual electron, relativistic time dilation, neutrino chirality, quark origin, and fundamental interactions (including gravitons). From now on, almost all quantum puzzles (e.g., wave-particle duality, quantum entanglement, Schrödinger’s cat) can be understood classically, just as prominent physicists such as Planck, Einstein, and Schrödinger longed for back then. This paper can be considered a blueprint of the Theory of Everything (TOE).