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Many countries around the world have all seen a sharp rise in COVID-19 cases as the second wave since the beginning of October 2020. Decline of antibodies response to severe acute respiratory syndrome coronavirus (SARS-CoV-2) that was reported exclusively in the early month increases the risk of reinfection for convalescent individuals. There is a current need to follow the maintenance of special antibodies against SARS-CoV-2. Here, we reported changes of antibodies against SARS-CoV-2 in convalescent patients over 8 months. Antibodies of all 20 participants targeting SARS-CoV-2 spike receptor binding-domain (RBD) had decreased from a mean OD450 value 1.78 to 0.38 over 8 months. The neutralizing antibody (NAb) titers decreased from the mean ID50 value 836 to 170. The NAb titers were significantly correlated with IgG level during 8 months (P<0.001). Furthermore, while RBD-specific IgG existence of 25% (5/20) convalescent plasma was undetectable, the NAb titers of 15% (3/20) convalescent plasma decreased below the threshold. In addition, compared to wild-type SARS-CoV-2 (S-D614), lower titers of neutralizing antibodies against its G614 variant were shown at 8 months after symptom onset. This study has important implications when considering antibody protection against SARS-CoV-2 reinfection.
Changes of Humoral Immunity Response in SARS-CoV-2 Convalescent Patients over 8 months
Background Regional information regarding the characteristics of patients with coronavirus disease (COVID)-19 is needed for a better understanding of the pandemic. Objective The objective of the study to describe the clinical features of COVID-19 patients diagnosed in a tertiary-care center in Mexico City and to assess differences according to the treatment setting (ambulatory vs. hospital) and to the need of intensive care (IC). Methods We conducted a prospective cohort, including consecutive patients with COVID-19 from February 26, 2020 to April 11, 2020. Results We identified 309 patients (140 inpatients and 169 outpatients). The median age was 43 years (interquartile range, 33-54), 59.2% men, and 18.6% healthcare workers (12.3% from our center). The median body mass index (BMI) was 29.00 kg/m2 and 39.6% had obesity. Compared to outpatients, inpatients were older, had comorbidities, cough, and dyspnea more frequently. Twenty-nine (20.7%) inpatients required treatment in the IC unit (ICU). History of diabetes (type 1 or 2) and abdominal pain were more common in ICU patients compared to non-ICU patients. ICU patients had higher BMIs, higher respiratory rates, and lower room-air capillary oxygen saturations. ICU patients showed a more severe inflammatory response as assessed by white blood cell count, neutrophil and platelet count, C-reactive protein, ferritin, procalcitonin, and albumin levels. By the end of the study period, 65 inpatients had been discharged because of improvement, 70 continued hospitalized, and five had died. Conclusions Patients with comorbidities, either middle-age obese or elderly complaining of fever, cough, or dyspnea, were more likely to be admitted. At admission, patients with diabetes, high BMI, and clinical or laboratory findings consistent with a severe inflammatory state were more likely to require IC.
CLINICAL AND EPIDEMIOLOGICAL CHARACTERISTICS OF PATIENTS DIAGNOSED WITH COVID-19 IN A TERTIARY CARE CENTER IN MEXICO CITY: A PROSPECTIVE COHORT STUDY.
The pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. During the years of 2020-2021, millions of humans have died due to SARS-CoV-2 infection and severe economic damage to the global economy has occurred. Unprecedented rapid investments in vaccine development have been made to counter the spread of SARS-CoV-2 among humans. While vaccines are a key pillar of modern medicine, SARS-CoV-2 has mutated as it spread among humans. Vaccines previously developed and approved by regulators are becoming less effective against new variants. One variant of SARS-CoV-2 known as B.1.351 that was first reported to be present in South Africa significantly reduces the efficacy of vaccines developed to date. Therapeutic options that work against the B.1.351 variant are therefore urgently needed to counteract reduced vaccine efficacy. We present here the discovery of recombinant alpaca antibodies that neutralise live virus of B.1.351 and other SARS-CoV-2 variants potently. The antibodies described here may be a useful tool for clinicians who are treating patients infected with B.1.351 and other SARS-CoV-2 for which there is currently no known highly effective treatment.
Development of highly potent neutralising nanobodies against multiple SARS-CoV-2 variants including the variant of concern B.1.351
Neuraminidase inhibitors (NAIs) are commonly used to treat influenza and are also considered the potential treatment for COVID-19. The association of using NAIs during pregnancy with the risk of adverse birth defects has been investigated repeatedly by epidemiological studies;however, results are largely inconsistent. We herein performed this meta-analysis to investigate the true association of NAIs with adverse birth defects, including preterm birth (PTB), low birth weight (LBW), and small for gestational age (SGA). A systematic search was performed through PubMed, Scopus, and Embase to indentify all pertinent studies;The ORs with their corresponding 95% CIs were extracted or calculated. Heterogeneity was assessed using the Cochran Q test and the I2 statistic. A random-effect model was used for this meta-analysis due to existing heterogeneity. Overall, eight studies were included in our analysis, meta-analysis using a random-effect model showed that NAIs during pregnancy reduced the risk of LBW (OR=0.78, 95% CI=0.66C0.91) and SGA (OR=0.76, 95% CI=0.67C 0.86) but is not associated with PTB (OR=1.01, 95% CI=0.87C1.16). Results of the present study suggested that NAIs during pregnancy are safe and may reduce the risk of LBW and SGA. However, further studies from different ethnic populations are warranted to confirm our results. ? 2021 by the authors.
Neuraminidase inhibitors during pregnancy and adverse birth outcomes: A meta-analysis
[Image: see text] Municipal sewage carries degraded and intact viral particles and RNA (ribonucleic acid) of SARS-CoV-2 (severe acute respiratory coronavirus 2), shed by COVID-19 (coronavirus disease 2019) patients, to sewage and eventually to wastewater treatment plants. Proper wastewater treatment can prevent uncontrolled discharges of the virus into the environment. However, the role of different wastewater treatment stages in reducing viral RNA concentrations is, thus far, unknown. Here, we quantified SARS-CoV-2 RNA in raw sewage and during the main stages of the activated sludge process from two wastewater treatment plants in Israel, on three different days during the 2020 COVID-19 outbreak. To reduce the detection limit, samples were concentrated prior to quantification by real-time polymerase chain reaction by a factor of 2C43 using ultrafiltration. On average, 1 log RNA removal was attained by each of the primary and secondary treatment steps; however, >100 copies of SARS-CoV-2 RNA/mL remained in the secondary effluents. Following chlorination, SARS-CoV-2 RNA was detected only once, likely due to an insufficient chlorine dose. Our results emphasize the capabilities and limitations of the conventional wastewater treatment process in reducing the SARS-CoV-2 RNA concentration and present preliminary evidence for the importance of tertiary treatment and chlorination in reducing dissemination of the virus to the environment.
Tracking SARS-CoV-2 RNA through the Wastewater Treatment Process
With the proliferation of news and the abundance of unknowns, COVID-19 information became rife with rumors and infiltrated consumers with confusion and information overload. In situations like this, it is important to provide consumers with credible and reliable information about the pandemic which is affecting their lives and livelihoods. Articles about coronavirus published in online versions of USA Today online, Wall Street Journal online and NYTimes.com between January and March 2020 were identified. Only articles where the search terms appeared in the headline were included as it was considered a more effective approach to understanding the health communication trends for this outbreak. These criteria resulted in 5,285 articles published on this topic during this time. All articles were imported into Dedoose mixed-methods software for thematic analysis. The frequency of each identified theme appearing in reviewed articles was counted, together with excerpts illustrating the specific theme. Overall, the five most common themes appearing in reviewed articles were financial impact of COVID-19 (11.6%), stories of affected individuals (7.0%), death and death rates (6.8%), precaution recommendations for public (6.2%), and quarantine (5.9%). The newspapers did not just report the numbers (number of infections, ventilators, deaths, economic losses) but they also reported the context of the pandemic, such as, impact on economy, efforts to slow the spread of infection, switch to working from home, presence of health disparities, scientific search for reliable COVID-19 tests, and effect on supply chains. News media play a vital role in enhancing understanding of pandemic, but also in shaping public response to public health messages.
Coverage of the COVID-19 Pandemic in the Online Versions of Highly Circulated U.S. Daily Newspapers
Coronavirus diseases (COVID-19) outbreak has been labelled a pandemic For the prioritization of treatments to cope with COVID-19, it is important to conduct rapid high-throughput screening of chemical compounds to repurposing the approved drugs, such as repositioning of chloroquine (Malaria drug) for COVID-19 In this study, exploiting supercomputer resource, we conducted high-throughput virtual screening for potential repositioning candidates of the protease inhibitor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Using the three dimensional structure of main protease (Mpro) of SARS-CoV-2, we evaluated binding affinity between Mpro and drug candidates listed in SWEETLEAD library and ChEMBL database Docking scores of 19,168 drug molecules at the active site of Mpro were calculated using Autodock Vina package Among the calculated result, we selected 43 drug candidates and ran molecular dynamics (MD) simulation to further investigate protein-drug interaction Among compounds that bind to the active site of SARS-CoV-2, we finally selected the 8 drugs showing the highest binding affinity;asunaprevir, atazanavir, dasabuvir, doravirine, fosamprenavir, ritonavir, voxilaprevir and amprenavir, which are the antiviral drugs of hepatitis C virus or human immunodeficiency virus We expect that the present study provides comprehensive insights into the development of antiviral medication, especially for the treatment of COVID-19 br /* Attached excel file contains a full list of results of docking calculations /div
Supercomputer-aided Drug Repositioning at Scale: Virtual Screening for SARS-CoV-2 Protease Inhibitor
OBJECTIVES: To evaluate the correlation between cycle threshold (Ct) value and occurrence of olfactory and taste dysfunction in COVID-19 patients. METHODS: This comparative study included COVID-19 patients diagnosed by reverse transcription- polymerase chain reaction (RT-PCR) based test at our hospital with mild to moderate disease. The demographic details and detailed clinical history of the patient, including history of loss of smell and taste was taken at the time of presentation. The patients were divided into 2 groups, group A: COVID-19 patients with OTD; group B: COVID-19 patients without OTD. 100 contiguous patients were recruited in each group. The COVID-19 test by RT-PCR was done and Ct value of the 3 genes: E (Envelope encoding) gene, N (Nucleocapsid encoding) gene, and RdRp (RNA-dependent RNA polymerase) gene, was used for data analysis. The Ct values of each of the three genes were compared between groups A and B. RESULTS: Group A and B did not differ significantly in terms of basic demographics. The differences in the Ct values of the 3 genes E gene, N gene and RdRp gene, of group A and B were found to be statistically significant (p = 0.005, p = 0.001 and p = 0.002, respectively). CONCLUSION: The patients with OTD had a lower Ct value at diagnosis, and hence, a higher viral load than those without OTD. The evaluation of Ct value and viral load in COVID-19 patients may help in further reducing the transmission of the virus in the community.
Is there a correlation between viral load and olfactory & taste dysfunction in COVID-19 patients?()
BACKGROUND Single-port transumbilical surgery is a well-established platform for minimally invasive abdominal surgery. The aim of this study was to compare the hemodynamics and inflammatory response of a novel transumbilical technique with that of a conventional transthoracic technique in thoracic exploration and lung resection in a canine model. METHODS Sixteen dogs were randomly assigned to undergo transumbilical thoracoscopy (n = 8) or standard thoracoscopy (n = 8). Animals in the umbilical group received lung resection via a 3-cm transumbilical incision in combination with a 2.5-cm transdiaphragmatic incision. Animals in the standard thoracoscopy group underwent lung resection via a 3-cm thoracic incision. Hemodynamic parameters (e.g., mean arterial pressure, heart rate, cardiac index, systemic vascular resistance, and global end-diastolic volume index) and inflammatory parameters (e.g., neutrophil count, neutrophil 2',7' -dichlorohydrofluorescein [DCFH] expression, monocyte count, monocyte inducible nitric oxide synthase expression, total lymphocyte count, CD4+ and CD8+ lymphocyte counts, the CD4+/CD8+ratio, plasma Creactive protein level, interleukin-6 level) were evaluated before surgery, during the operation, and on postoperative days 1, 3, 7, and 14. RESULTS Lung resections were successfully performed in all 16 animals. There were 2 surgery-related mortality complications (1 animal in each group). In the transumbilical group, 1 death was caused by early extubation before the animal fully recovered from the anesthesia. In the thoracoscopic group, 1 death was caused by respiratory distress and the complication of sepsis at 5 days after surgery. There was no significant difference between the two techniques with regard to the hemodynamic and immunologic impact of the surgeries. CONCLUSION This study suggests that the hemodynamic and inflammatory changes with endoscopic lung resection performed by the transumbilical approach are comparable to those after using the conventional transthoracic approach. This information is novel and relevant for surgeons interested in developing new surgical techniques in minimally invasive surgery.
Hemodynamic and inflammatory responses following transumbilical and transthoracic lung wedge resection in a live canine model.
We examined the pathogens, morphologic patterns, and risk factors associated with bovine respiratory disease (BRD) in 136 recently weaned cattle ("weanlings"), 6-12 mo of age, that were submitted for postmortem examination to regional veterinary laboratories in Ireland. A standardized sampling protocol included routine microbiologic investigations as well as polymerase chain reaction and immunohistochemistry. Lungs with histologic lesions were categorized into 1 of 5 morphologic patterns of pneumonia. Fibrinosuppurative bronchopneumonia (49%) and interstitial pneumonia (48%) were the morphologic patterns recorded most frequently. The various morphologic patterns of pulmonary lesions suggest the involvement of variable combinations of initiating and compounding infectious agents that hindered any simple classification of the etiopathogenesis of the pneumonias. Dual infections were detected in 58% of lungs, with Mannheimia haemolytica and Histophilus somni most frequently recorded in concert. M. haemolytica (43%) was the most frequently detected respiratory pathogen; H. somni was also shown to be frequently implicated in pneumonia in this age group of cattle. Bovine parainfluenza virus 3 (BPIV-3) and Bovine respiratory syncytial virus (16% each) were the viral agents detected most frequently. Potential respiratory pathogens (particularly Pasteurella multocida, BPIV-3, and H. somni) were frequently detected (64%) in lungs that had neither gross nor histologic pulmonary lesions, raising questions regarding their role in the pathogenesis of BRD. The breadth of respiratory pathogens detected in bovine lungs by various detection methods highlights the diagnostic value of parallel analyses in respiratory disease postmortem investigation.
Pathogens, patterns of pneumonia, and epidemiologic risk factors associated with respiratory disease in recently weaned cattle in Ireland.
Pada awal Maret tahun 2019 Indonesia dilanda dengan wabah COVID-19 (Corona). Peningkatan jumlah pasien terinfeksi virus COVID-19 semakin melonjak hari demi hari dan sudah sulit dikendalikan. Untuk mencegah bertambahnya kasus COVID-19 adalah membuat cluster atau pengelompokan wilayah tertentu (kelurahan) berdasarkan jumlah positif, dirawat, sembuh, meninggal dan isolasi. Pengelompokan ini akan membantu pemerintah DKI Jakarta dalam memberikan penanganan yang sesuai dengan pola kelurahan tersebut. Data yang akan menjadi kajian penelitian adalah mengenai data persebaran status terinfeksi kasus COVID-19 di Provinsi DKI Jakarta pada tanggal 20 Mei 2021. Algoritma K-Medoids merupakan metode yang dapat menentukan suatu set cluster di antara sekelompok data yang mendekati suatu objek. Berdasarkan kajian penelitian yang sudah di lakukan dapat diambil kesimpulan bahwa pada teknik data mining dalam pengelompokkan total kasus terinfeksi COVID-19 berdasarkan kelurahan di Provinsi DKI Jakarta menggunakan algoritma K-Medoids dengan tiga Cluster. Cluster 0, Cluster 1, Cluster 2. Kasus terinfeksi COVID-19 tertinggi pada Provinsi DKI Jakarta ditunjukkan pada Cluster 0 dengan 31 wilayah. Hasil penelitian Pengelompokkan ini akan membantu pemerintah DKI Jakarta dalam memberikan penanganan yang sesuai dengan pola kelurahan. K-Medoids dapat diterapkan menggunakan data yang berjumlah besar dengan atribut yang kompleks. Kata Kunci: COVID-19, K-Medoids, Data Mining, Clustering In early March 2019, Indonesia was hit by the COVID-19 (Corona) outbreak. The increase in the number of patients infected with the COVID-19 virus is increasing day by day and is already difficult to control. Jakarta is no exception. To prevent the increase in cases of COVID-19, it is necessary to create a cluster or grouping of certain areas (Urban village) based on the number of positive, treated, recovered, died and isolated. This grouping will assist the DKI Jakarta government in providing appropriate handling according to the Urban village pattern. The data that will be used as a research study is the data on the distribution of the status of infected cases of COVID-19 in DKI Jakarta Province on May 20, 2021. The K-Medoids algorithm is a method that can determine a set of clusters among a group of data that is close to an object. Based on the research studies that have been carried out, it can be concluded that in the data mining technique, the total grouping of COVID-19 infected cases based on urban areas in DKI Jakarta Province uses the k-medoids algorithm with three clusters. Cluster 0, cluster 1, cluster 2. The highest COVID-19 infected cases in DKI Jakarta Province are shown in cluster 3 with 31 regions. The results of this grouping research will assist the DKI Jakarta government in providing appropriate handling according to the Urban village pattern. K-Medoids can be implemented using large amounts of data with complex attributes. Keywords: COVID-19, K-Medoids, Data Mining, Clustering.
Implementasi algoritma K-Medoids untuk clustering wilayah terinfeksi kasus COVID-19 di DKI Jakarta
Over the past decade, advances in digital trends and technology have greatly impacted the medical field with rapid delivery of and access to information. The field of cardiovascular medicine in particular has seen major technological advances and is well versed in the use of digital platforms and social media. In these unprecedented times of the COVID-19 pandemic, social media and other digital platforms are essential tools for communication, education, and delivery of information. In this review, we discuss the ways virtual learning and social media are changing medical education and research.
Impact of Social Media and Virtual Learning on Cardiology During the COVID-19 Pandemic Era and Beyond.
In March 2020 the World Health Organization declared the pandemic statedue to COVID-19 imposing strict confinement of the world population. People were forced to spend more time at home, changing some daily routines, including social interactions, the possibility to perform sports, and diet habits. These changes could exert a greater impact on patients suffering from chronic diseases, such as endocrine patients. This study aimed to assess the effects of Covid-19 induced quarantine on daily habits in a group of patients with endocrine disorders, focusing on food consumption, eating, and sleep habits during the confinement. Eighty-five endocrine patients were enrolled. A structured interview was administered investigating: socio-demographic information, general medical conditions and habits adopted during the quarantine. All patients underwent the Spielberger State Anxiety Inventory (STAI-Y1) to assess state anxiety. Subjects had mainly a sedentary lifestyle. We found a significant increase in the number of cigarettes in smokers, an increase of meals consumed during the confinement and a high rate of sleep disorder occurrence, especially insomnia. The changes of daily habits were, probably, due to the alterations of routine, that determined more bore and inactivity during the day.
Effects of COVID-19 in Endocrine Patients: Results of a Sicilian Experience
The potential transformation of labour markets by the emergence of online labour platforms has triggered an intense academic, media and policy debate, but its true scale remains speculation. Nevertheless, adequate policy responses hinge on a good understanding of dynamics C something that will only grow in importance with the labour market crisis created by the COVID-19 pandemic. With technologically enabled remote work, growing demand for services such as food delivery or care, as well as rising unemployment and the financial strain on many workers, platform work may resume its rapid growth. Therefore, there is a need for good quality data on the prevalence of platform and other forms of precarious work in society.This working paper provides a critical assessment of different approaches to counting gigs;that is, estimating the scale of engagement in platform work in the general population. The aim is to examine the main obstacles encountered in previous studies, the reasons for surprising or contradictory results and possible sources of error, but also the lessons that can be learned for future research. This is illustrated with key research in this area, ranging from large projects conducted by national statistical offices to smaller scale independent research, from national to (nearly) global scale.
Counting Gigs: How Can we Measure the Scale of Online Platform Work?
[This corrects the article DOI: 10.2196/21329.].
Correction: Identifying and Ranking Common COVID-19 Symptoms From Tweets in Arabic: Content Analysis
Most vitamins are primarily ingested from foods. However, it has been reported that intakes of some vitamins do not meet the nutrition reference values even in high-income countries. In this case, vitamin-fortified foods and/or vitamin supplements are helpful to fix insufficient/deficient status. However, it is not clear whether consumers are aware of their nutritional status or whether they use these products efficiently. To address this issue, we conducted an online cross-sectional questionnaire survey among 14,741 Japanese adults (over 20 years old, 7489 males and 7252 females) concerning the perceptions and prevalence of vitamin-fortified food and/or vitamin supplements. Differences in distribution among groups were compared using the chi-squared test. According to dietary habits, 33.2% of the participants consumed a well-balanced diet every day, but 25.5% could not because of time (41.6%) or money (36.9%) constraints. The perception of each vitamin varied: the highest was for vitamin C (93.2%) and the lowest was for biotin (41.9%). In addition, only a portion of the participants believed that they took sufficient amounts of each vitamin; the highest was vitamin C (22.3%) and the lowest was biotin (5.2%). Despite this situation, most did not use vitamin-fortified food and/or vitamin supplements due to economic reasons. Among vitamin-fortified food and/or vitamin supplement users, the purposes for the usage of these products were varied, such as maintaining health (80.5%), supplementation of nutrients (47.8%), beauty-related purposes (27.5%), and to prevent infectious disease (23.2%). To remedy nutritional status in individuals, it is important to improve not only consumer awareness but also the environment, which can lead consumers to use acceptable vitamin products without any burden.
The Perception of Vitamins and Their Prevalence in Fortified Food and Supplements in Japan
Ending the West Africa Ebola virus disease (EVD) outbreak required an unprecedented international response. For the United States, participation in the international response to the West Africa EVD outbreak provided an opportunity to learn important lessons in four key domains critical to preparing for future outbreaks of EVD and other serious communicable diseases: (i) safe and effective patient care, (ii) the role of experimental therapeutics and vaccines, (iii) infection control, and (iv) hospital and community preparedness.
Preparing for Serious Communicable Diseases in the United States: What the Ebola Virus Epidemic Has Taught Us.
Context: The outbreak of the SARS-CoV-2 pandemic of the new COVID-19 disease (COVID-19 for short) demands empowering existing medical, economic, and social emergency backend systems with data analytics capabilities. An impediment in taking advantages of data analytics in these systems is the lack of a unified framework or reference model. Ontologies are highlighted as a promising solution to bridge this gap by providing a formal representation of COVID-19 concepts such as symptoms, infections rate, contact tracing, and drug modelling. Ontology-based solutions enable the integration of diverse data sources that leads to a better understanding of pandemic data, management of smart lockdowns by identifying pandemic hotspots, and knowledge-driven inference, reasoning, and recommendations to tackle surrounding issues. Objective: This study aims to investigate COVID-19 related challenges that can benefit from ontology-based solutions, analyse available tool support, and identify emerging challenges that impact research and development of ontologies for COVID-19. Moreover, reference architecture models are presented to facilitate the design and development of innovative solutions that rely on ontology-based solutions and relevant tool support to address a multitude of challenges related to COVID-19. Method: We followed the formal guidelines of systematic mapping studies and systematic reviews to identify a total of 56 solutions - published research on ontology models for COVID-19 - and qualitatively selected 10 of them for the review. Results: Thematic analysis of the investigated solutions pinpoints five research themes including telehealth, health monitoring, disease modelling, data intelligence, and drug modelling. Each theme is supported by tool(s) enabling automation and user-decision support. Furthermore, we present four reference architectures that can address recurring challenges towards the development of the next generation of ontology-based solutions for COVID-19 analytics.
An Overview of Ontologies and Tool Support for COVID-19 Analytics
Injustice in surveillance may occur if surveillance is directed towards protecting the health of some but the data are gathered at the expense of others. Failures to surveille may be unjust if they leave people subject to health inequities. Such injustice in surveillance may undermine trust. This chapter explores injustice in surveillance and ethical responses. Primary examples are drawn from surveillance of environmental risks, especially those involving unclean or contaminated water. These injustices occur across the globe, from Flint, Michigan, in the United States to refugee camps in Bangladesh. The chapter also takes up the obligations of others when societies are failing to act justly, arguing for the importance of addressing corrosive disadvantages suffered especially by children but by other disadvantaged populations as well.
Surveillance and Equity: Identifying Hazards in the Environment
Owing to limitations imposed by the experimental requirements, it is difficult to carry out pressure-volume-temperature experiments on CO2-containing natural gas in high-temperature and ultrahigh-pressure gas reservoirs. Relevant research is also insufficient, which has led to a lack of clarity in current understanding of the microscopic mechanism of variations in the deviation factor of high-CO2 natural gas under high-temperature and ultrahigh-pressure conditions. This has greatly limited the development of natural gas reservoirs containing CO2. To reveal the microscopic mechanism of variations in the deviation factor of natural gas containing CO2 as a function of pressure under high-temperature and high-pressure conditions, by physical simulation experiments, the deviation factors of samples of sour natural gas with known CO2 contents from the Ledong gas reservoir were determined. Then, according to the idealized parameters of the physical experiment, a molecular model of natural gas containing CO2 was established using molecular simulation methods. Changes in molecular density, molecular volume, nonbonding interaction energy, potential energy, and kinetic energy during variations in the deviation factor of a CO2-containing natural gas system as a function of pressure under high-temperature and ultrahigh-pressure conditions were quantitatively studied. Using molecular simulation techniques, it was found that the changes in total energy, kinetic energy, and potential energy between molecules are the internal factors that cause variations in the deviation factor of natural gas systems containing CO2 under ultrahigh-temperature and high-pressure conditions. The results show that the increase of carbon dioxide content in natural gas will cause the total energy of natural gas molecules to decrease when the pressure is constant. This means that the higher the CO2 content in natural gas, the easier it will be compressed. This study should lay the foundation for investigating the mechanisms of the occurrence of CO2-containing natural gas, as well as facilitating the exploitation of CO2-containing natural gas.
Microscopic Mechanism of Variations in Physical Parameters of Natural Gas Containing CO2 at Ultrahigh Temperature and High Pressure

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