Initial Stage Research Articles

Comparative analysis of emotional facial expression recognition and empathy in children with prader-willi syndrome and autism spectrum disorder

BackgroundPrader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder that is often comorbid with Autism Spectrum Disorder (ASD). Due to the close association between these two conditions, and recognizing that Theory of Mind (ToM) is related to social behaviors in ASD, there is a growing interest in studying the reciprocity of social communication between these two groups.MethodThe primary objective of this study was to compare how children (n = 45) with PWS (n = 15), ASD (n = 15), and a control group (n = 15) respond to emotion recognition of facial expressions and empathy, which are both concepts related to ToM. The study utilized two tools named FEEL and Deusto-e-Motion 1.0. We also evaluated the Working Memory index of the WISC-IV scale, the Social Perception domain of the NEPSY-II battery, and the SCQ in both clinical groups.ResultsOur findings suggest that individuals with PWS exhibit lower accuracy in recognizing facial expressions and empathy compared to the control group. Both clinical groups exhibited a delayed reaction time compared to the control group. Children with PWS display difficulties in recognizing emotions of disgust and surprise. In terms of cognitive empathy, children with PWS showed a greater inclination to respond to disgust as compared to children with ASD.ConclusionsThis study represents the initial stage in comprehending the emotional and empathetic abilities of children with PWS and ASD. The findings can provide valuable insights for developing future interventions.

The effect of moderate and vigorous aerobic exercise training on the cognitive and walking ability among stroke patients during different periods: A systematic review and meta-analysis.

The study examined whether rehabilitation using aerobic exercise is more appropriate for patients less than 3 months post-stroke or more appropriate for patients more than 3 months post-stroke. PubMed, Embase, Web of Science, Scopus and CNKI databases were searched from inception to September 2023. All studies included must be written in English and grey literature was excluded. The quality of the study was evaluated using the PEDro scale. Standard mean difference (SMD) and 95% confidence interval (CI) were calculated. The primary outcomes are cognitive ability and walking ability. The intervention of the experimental group must be or include high-intensity aerobic training or moderate-intensity aerobic training. In addition, we required low intensity routine exercises in control group. Only 15 studies were included in this meta-analysis. The results showed that aerobic exercise has a positive rehabilitation effect on cognitive and walking ability of stroke patients. Global Cognitive Function (SMD = 0.81 95%CI 0.49-1.12), Walking Capacity (SMD = 1.19, 95%CI 0.75-1.62), VO2peak (SMD = 0.97, 95%CI 0.66-1.28), and brain-derived neurotrophic factor (SMD = 2.73, 95%CI 2.03-3.43). We further observed that patients who suffered a stroke within the past three months exhibited superior rehabilitation outcomes compared to patients who suffered a stroke more than three months ago, specifically in terms of cognitive ability, walking tests, and cardiopulmonary function. It is recommended to carry out treatment for patients in the initial stage of stroke, and it is required to pay attention to exercise intensity in the process of treatment to ensure patient safety.

The Effectiveness of Hand Exercise on Limb Function in Patient Coronary Artery Disease Posttransradial Artery Catheterization: Systematic Review

Coronary Artery Disease (CAD) is leading cause of mortality worldwide. Catheterization using the transradial arterial (TRA) technique has been able to reduce morbidity and mortality rates from CAD, but this procedure also contributes to the occurrence of complications. The aim of this study was to search literature and analyse articles discussing the use of hand exercise on improving limb function in patients posttransradial cardiac catheterization. Methods: The design used was a systematic review with PRISMA adaptation. Articles were searched using databases: ScienceDirect, ProQuest, PubMed, Scopus and Hand Searching in Google Scholar. The keywords of article search were using “Coronary artery disease” AND “transradial artery catheterization” OR “Trans cardiac Catheterization” AND “hand exercise” AND “limb function. In the initial stage of information search on 5 October 2023, the total number of articles obtained before selection was carried out based on inclusion and exclusion criteria was 7273 articles. From the five databases used, selection was then carried out according to the inclusion and exclusion criteria. The inclusion criteria were research articles published in the last 10 years (2013-2023); use English; a journal article and open access; Involves adult respondents and full text articles. Exclusion criteria were encyclopedia articles, book chapters, conferences, correspondence, editorials, news, practice guidelines, protocols, systematic reviews, literature reviews and meta analysis. The results are discussing 7 articles published from 2013-2023. Conclusions Hand exercises are useful for restoring limb function within two hours after the procedure and over a long period of time.

Relationships of crystallinity and reaction rates for enzymatic degradation of poly (ethylene terephthalate), PET.

Biocatalytic degradation of plastic waste is anticipated to play an important role in future recycling systems. However, enzymatic degradation of crystalline poly (ethylene terephthalate) (PET) remains consistently poor. Herein, we employed functional assays to elucidate the molecular underpinnings of this limitation. This included utilizing complementary activity assays to monitor the degradation of PET disks with varying crystallinity (XC), as well as determining enzymatic kinetic parameters for soluble PET fragments. The results indicate that an efficient PET-hydrolase, LCCICCG, operates through an endolytic mode of action, and that its activity is limited by conformational constraints in the PET polymer. Such constraints become more pronounced at high XC values, and this limits the density of productive sites on the PET surface. Endolytic chain-scissions are the dominant reaction type in the initial stage, and this means that little or no soluble organic product are released. However, endolytic cuts gradually and locally promote chain mobility and hence the density of attack sites on the surface. This leads to an upward concave progress curve; a behavior sometimes termed lag-phase kinetics.

Molecular Insights of Excessive Water Cut during Cyclic Gas Injection in Liquid-Rich Shale Reservoirs: Contributions of Hydrocarbon Condensation and Water Trapping

Summary In a recent pilot test of cyclic gas injection (huff ‘n’ puff) in a Permian shale reservoir, excessive water product was observed, the reason for which remains unclear. In this work, we analyze the mechanisms of gas huff ‘n’ puff processes using molecular dynamics (MD) simulations and explain the reason for the high water-cut phenomenon. We aim to investigate the hydrocarbon-water-rock interactions during the gas injection as well as production within a shale rock in the pore scale. To mimic the heterogeneous pore structure of the shale rock, we have designed a pore system, including a bulk pore, a pore throat, and a dead-end pore. We simulate the distribution of different fluids during the initial equilibrium stage, the primary depletion stage, and the huff ’n’ puff stage. The results show that an excessive amount of water is trapped by the condensation mechanism in the larger pores during the primary depletion stage. The water is then recovered with the injection of working (lean) gases. Moreover, we have analyzed the effect of different injection gases (IGs) and found that carbon dioxide (CO2) yields a higher water cut compared with methane (C1). Moreover, our findings have revealed the trapping mechanisms of hydrocarbon-water mixtures in shale rocks and have highlighted the impacts of pore structures on the recovery of shale reservoirs. As such, we have provided a potential explanation of the observed phenomenon.

Prediction of Diabetic Retinopathy using Deep Learning with Preprocessing

INTRODUCTION: When Diabetic Retinopathy (DR) is not identified promptly; it frequently results in sight impairment. To properly diagnose and treat DR, preprocessing of picture methods and precise prediction models are essential. With the help of numerous well-liked filters and a Deep CNN (Convolutional Neural Network) model, the comprehensive method for DR image preparation and prognosis presented in this research is described. Using the filters that focus boundaries and contours in the ocular pictures is the first step in the initial processing stage. This procedure tries to find anomalies linked to DR. By the usage of filters, the excellence of pictures can be developed and minimize disturbances, preserving critical information. The Deep CNN algorithm has been trained to generate forecasts on the cleaned retinal pictures following the phase of preprocessing. The filters efficiently eliminate interference without sacrificing vital data. Convolutional type layers, pooling type layers, and fully associated layers are used in the CNN framework, which was created especially for image categorization tasks, to acquire data and understand the relationships associated with DR.
 OBJECTIVES: Using image preprocessing techniques such as the Sobel, Wiener, Gaussian, and non-local mean filters is a promising approach for DR analysis. Then, predicting using a CNN completes the approach. These preprocessing filters enhance the images and prepare them for further examination. The pre-processed images are fed into a CNN model. The model extracts significant information from the images by identifying complex patterns. DR or classification may be predicted by the CNN model through training on a labeled dataset.
 METHODS: The Method Preprocessing is employed for enhancing the clarity and difference of retina fundus picture by removing noise and fluctuation. The preprocessing stage is utilized for the normalization of the pictures and non-uniform brightness adjustment in addition to contrast augmentation and noise mitigation to remove noises and improve the rate of precision of the subsequent processing stages.
 RESULTS: To improve image quality and reduce noise, preprocessing techniques including Sobel, Wiener, Gaussian, and non-local mean filters are frequently employed in image processing jobs. For a particular task, the non-local mean filter produces superior results; for enhanced performance, it may be advantageous to combine it with a CNN. Before supplying the processed images to the CNN for prediction, the non-local mean filter can assist reduce noise and improve image details.
 CONCLUSION: A promising method for DR analysis entails the use of image preprocessing methods such as the Sobel, Wiener, Gaussian, and non-local mean filters, followed by prediction using a CNN. These preprocessing filters improve the photos and get them ready for analysis. After being pre-processed, the photos are sent into a CNN model, which uses its capacity to discover intricate patterns to draw out important elements from the images. The CNN model may predict DR or classification by training it on a labeled dataset. The development of computer-aided diagnosis systems for DR is facilitated by the integration of CNN prediction with image preprocessing filters. This strategy may increase the effectiveness of healthcare workers, boost patient outcomes, and lessen the burden of DR.

Characteristics of the Discoloration Switching Phenomenon of 4H-SiC Single Crystals Grown by PVT Method Using ToF-SIMS and Micro-Raman Analysis.

The discoloration switching appearing in the initial and final growth stages of 4H-silicon carbide (4H-SiC) single crystals grown using the physical vapor transport (PVT) technique was investigated. This phenomenon was studied, investigating the correlation with linear-type micro-pipe defects on the surface of 4H-SiC single crystals. Based on the experimental results obtained using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and micro-Raman analysis, it was deduced that the orientation of the 4H-SiC c-axis causes an axial change that correlates with low levels of carbon. In addition, it was confirmed that the incorporation of additional elements and the concentrations of these doped impurity elements were the main causes of discoloration and changes in growth orientation. Overall, this work provides guidelines for evaluating the discoloration switching in 4H-SiC single crystals and contributes to a greater understanding of this phenomenon.

Tungsten mineralization in the Huangjindong gold deposit, southern China: Insights from scheelite texture, in-situ trace elements and Sr isotope compositions

Scheelite and wolframite are two primary tungsten minerals in nature. The occurrence of tungsten minerals varies in different types of deposits, with scheelite rather than wolframite typically forming in orogenic gold deposits. However, the explanation for this phenomenon remains unclear. Huangjindong deposit, located in the center of the Jiangnan Orogenic Belt in southern China, is a typical orogenic gold deposit with scheelite mineralization. Texture, in-situ trace elements and Sr isotope compositions of scheelite from this deposit were investigated to explore the formation process of scheelite and the source of tungsten of similar orogenic gold deposits.Three hydrothermal stages have been identified at this deposit: milky scheelite + quartz (pre-gold Stage I); gold + sericite + sulfide + quartz (syn-gold Stage II); and dolomite + quartz (post-gold Stage III). Scheelite primarily occurs during the initial pre-gold stage. Local color differences in CL image have developed along rims and in domains adjacent to fractures of scheelite due to slight late-stage hydrothermal alteration of scheelite along their fractures. The intense development of sericite and chlorite alteration in the host rocks indicates that the water–rock reaction consumed a large amount of H+. Within the scheelite-quartz veins, the presence of brecciated slate enclaves and localized quartz geodes, indicating that the fluid experienced significant pressure drop. This indicates that the water–rock reaction and the decrease in pressure resulted in the precipitation of scheelite. The dominance of tungsten mineral precipitation due to pressure reduction serves as the main factor driving the development of scheelite over wolframite within the deposit, which also elucidates the reason that tungsten mineralization associated with orogenic gold deposits predominantly features scheelite. The characteristics of scheelite without oscillatory zoning, high Sr (1180–8600 ppm) and low Mo (bdl-0.18 ppm) concentrations, and flat REE pattern are similar to those of scheelite in orogenic gold deposits worldwide. The high 87Sr/86Sr ratio (0.7539–0.7663) indicates that the tungsten-bearing ore-forming fluids derived from deep-seated metamorphic fluids.

Prostate-Specific Membrane Antigen PET/CT Detection of Prostate Cancer Metastasis to Thyroid and Cricoid Cartilages.

Prostate-specific membrane antigen (PSMA) PET/CT has revolutionized the imaging of prostate cancer. Historically, prostate cancer metastasis to thyroid and cricoid cartilages was thought to be exceedingly rare, with only a few reported cases in the literature. Prostate cancer metastasis to the laryngeal cartilages was detected in 4 of 221 patients who underwent imaging with 18 F-PSMA (Pylarify) or 68 Ga-PSMA (Illuccix) PET/CT for initial staging of high-risk prostate cancer or restaging evaluation in the setting of biochemical recurrence from April 2022 through October 2023. The increased sensitivity and specificity of PSMA PET/CT allow for the detection of previously occult metastatic disease.

Technological advancements, digital transformation, and future trends in blood transfusion services

Misidentification, mistransfusion, and pre-analytical errors are all regarded as major challenges and risks in safe blood transfusion procedures. To provide a high level of accuracy, traceability, automation, and reliability in blood transfusion services, traditional methods should be upgraded with modern technologies such as block chain technology, machine learning, artificial intelligence (AI), artificial neural networks, algorithm-based learning, and the implementation of radio frequency identification (RFID) and the internet of things (IoT). This technology helps reduce errors, retrieve data, forecast blood demand, reduce blood waste, manage blood storage, and manage workload, ensuring transfusion safety. The technology is still in the initial stages of development and by addressing issues such as data loss, patient data privacy, and cost-effectiveness, the technology will become a revolution in transfusion services.

DNA methylation mediates the effects of PM2.5 and O3 on ceramide metabolism: A novel mechanistic link between air pollution and insulin resistance

Insulin resistance (IR), linked to air pollution, is an initial stage of early-onset Type 2 diabetes mellitus (T2DM). While ceramide metabolism plays an important role in IR pathogenesis, the effects of air pollution on this process and its mechanisms remain unclear. We recruited young adults aged 18–30 years to a panel study in Wuhan, China. Using personal portable devices and stationary monitoring stations, we tracked particulate matter with aerodynamic diameters≤ 2.5 µm (PM2.5) and Ozone (O3) levels. Liquid chromatography/mass spectrometry (LC-MS) based metabolomics quantified ceramide metabolism, and Illumina Infinium Human Methylation 850 kBeadChip assay measured deoxyribonucleic acid (DNA) methylation. Linear mixed-effects models assessed relationships of air pollution with i) IR indexes, ii) ceramide metabolism, and iii) DNA methylation. Mediation analysis was subsequently performed to evaluate the potential mediating effect of DNA methylation in the association between air pollution and ceramide metabolism. PM2.5 and O3 were associated with elevated IR. Specifically, each 10 μg/m3 increase in PM2.5 and O3 at lag0–12 h significantly increased triglyceride‑glucose index (TyG index) and TyG-BMI (TyG - Body mass index) by 0.88%, 0.89% and 0.26%, 0.26%, respectively. Furthermore, levels of eight ceramides were altered by air pollution exposure, and nine methylated CpG sites in inflammation genes mediated the effects of air pollution on ceramide metabolism. Our findings imply the existence of a novel mechanism connecting air pollution to IR.

A Spatiotemporal Controllable Biomimetic Skin for Accelerating Wound Repair.

Skin injury repair is a dynamic process involving a series of interactions over time and space. Linking human physiological processes with materials' changes poses a significant challenge. To match the wound healing process, a spatiotemporal controllable biomimetic skin is developed, which comprises a three-dimensional (3D) printed membrane as the epidermis, a cell-containing hydrogel as the dermis, and a cytokine-laden hydrogel as the hypodermis. In the initial stage of the biomimetic skin repair wound, the membrane frame aids wound closure through pre-tension, while cells proliferate within the hydrogel. Next, as the frame disintegrates over time, cells released from the hydrogel migrate along the residual membrane. Throughout the process, continuous cytokines release from the hypodermis hydrogel ensures comprehensive nourishment. The findings reveal that in the rat full-thickness skin defect model, the biomimetic skin demonstrated a wound closure rate eight times higher than the blank group, and double the collagen content, particularly in the early repair process. Consequently, it is reasonable to infer that this biomimetic skin holds promising potential to accelerate wound closure and repair. This biomimetic skin with mechanobiological effects and spatiotemporal regulation emerges as a promising option for tissue regeneration engineering.

A Review of Renewable Energy Communities: Concepts, Scope, Progress, Challenges, and Recommendations

In recent times, there has been a significant shift from centralized energy systems to decentralized ones. These systems aim to satisfy local energy needs using renewable resources within the community. This approach leads to decreased complexity and costs, improved efficiency, and enhanced local resilience and supports energy independence, thereby advancing the transition toward zero carbon emissions. Community energy plays a pivotal role globally, particularly in European countries, driven by citizen engagement in generating power from renewable sources. The European Union, known for its focus on social innovation and citizen participation, recognizes the essential role of energy communities in its latest energy strategy. The concept for creating local energy communities or community-based energy projects has gained worldwide attention, demonstrating the economic, environmental, and efficiency benefits for using renewable energy sources. However, there is a noticeable gap in research covering all the updated aspects of renewable energy communities. This article provides an in-depth review of energy communities, especially renewable energy communities, exploring their concepts, scope, benefits, and key activities. It also sheds light on their progress by presenting results and analyses. Some countries have shown significant advancement, others are in the initial stages, and a few have partially adopted REC implementation according to the Renewable Energy Directive II. Additionally, it discusses the main challenges and potential recommendations to enhance the growth of renewable energy communities. This work is a valuable resource, emphasizing the importance of citizen involvement and offering insights into various aspects of community energy for sustainable energy transition. It also provides practical insights and valuable information for policymakers, researchers, industry professionals, and community members who are keen on promoting sustainable, community-driven energy systems.

Synergetic Mechanism of Multiple Industrial Solid Waste-Based Geopolymer Binder for Soil Stabilization: Optimization Using D-Optimal Mixture Design

In order to improve the comprehensive utilization rate of industrial solid waste and the road quality, a novel low-carbon and environmental friendly soil stabilizer is proposed. In this study, steel slag (SS), carbide slag (CS), blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG) were used as raw materials to develop a multiple industrial solid waste-based soil stabilizer (MSWSS). The optimal mix ratio of the raw materials determined by D-optimal design was as follows: 5% SS, 50% CS, 15% BFS, 15% DG, and 15% FA. The 7-day unconfined compressive strength (UCS) of MSWSS-stabilized soil was 1.7 MPa, which was 36% higher than stabilization with ordinary portland cement (OPC) and met the construction requirements of highways. After 7 days of curing, the UCS of MSWSS-stabilized soil was significantly higher than that in the OPC group. X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis indicated that the prominent hydration products were ettringite (AFt) and C-S-H gel. The results showed that an amount of AFt and C-S-H were formed in the initial stage of curing, resulting in a rapid improvement in early UCS. As the curing proceeded, the content of AFt and C-S-H increased constantly and grew intertwined with each other, which lead to the denser microstructure of stabilized soil and better mechanical strength.

Monte Carlo simulation of planar GaAs nanowire growth

The Monte Carlo model for the planar GaAs nanowire growth via the vapor–liquid-solid mechanism on GaAs substrate using a gallium droplet as a catalyst is realized. The effect of temperature, Ga and As2 deposition rates, substrate orientation and surface properties on the morphology of planar GaAs nanowires is considered. It is shown, that at the initial stages of nanowire growth, a 3D GaAs crystal is formed under a gallium droplet, which sets the nanowire growth direction. The range of temperatures and deposition rates of gallium and arsenic, which ensure the planar nanowire formation on the GaAs(111)A surface, is determined. The investigation of surface properties influence on the nanowire morphology showed that the arsenic diffusion influx into a gallium droplet is of critical importance for the planar GaAs nanowire growth. Ways for achieving a unidirectional growth of planar nanowires on singular and vicinal GaAs surfaces are proposed.

The Geochemical Characteristics of Trace Elements in the Magnetite and Fe Isotope Geochemistry of the Makeng Iron Deposit in Southwest Fujian and Their Significance in Ore Genesis

The Makeng iron deposit in southwest Fujian is a significant iron polymetallic deposit containing various types of iron ore, including garnet magnetite, diopside magnetite, and quartz magnetite. The metallogenetic type of the deposit has been a subject of debate, particularly in relation to the genesis of magnetite and the source of iron. In situ microanalysis of trace elements in magnetite from different ores shows relatively low levels of V, Ti, Cu, and Zn, with higher concentrations of Ca and Si, indicating the characteristics of a skarn type deposit. The δ57Fe values of the magnetite range from −0.091‰ to 0.317‰. Combining these data, whole-rock iron isotope analyses, including Juzhou and Dayang granites, diabase, and the Lower Carboniferous Lindi Formation sandstone, suggest that Fe in the magnetite primarily originates from granitic pluton, with potential contributions from diabase and the Lower Carboniferous Lindi Formation sandstone. Combined with field work, these results indicate that Makeng iron deposit is a skarn-type magnetite deposit associated with Yanshanian granitic intrusions. Therefore, the initial ore-forming fluid is postulated to be a high-temperature magmatic hydrothermal fluid with high oxygen fugacity. This fluid infiltrates spaces such as interlayer fracture zones between the Upper Carboniferous Jingshe Formation–Middle Permian Qixia Formation carbonate rocks and the Lower Carboniferous Lindi Formation sandstone, resulting in diverse magnetite ores due to metasomatism. The mineralization process of the Makeng iron deposit is basically the same, as it is composed of typical skarn deposits. Magnetite was mainly formed during calcic skarn formation stage, and this process persisted until the initial phase of the retrograde alteration of skarns. In contrast, sulfide minerals, including molybdenite, sphalerite, and galena, precipitated during the quartz–sulfide stage.

Отражение Русско-японской войны 1904–1905 гг. в повседневности Нижегородской губернии

In this article, the authors, using the example of Nizhny Novgorod, examined the dynamics of changes in the relationship between society and government in the Russo-Japanese War. The attitude of the classes to the war and its results, as well as the impact that the conclusion of the Portsmouth Peace had on the development of the revolutionary movement in the province were analyzed. The authors noted that in the initial stages of the war, the population of the Nizhny Novgorod province responded with a surge of patriotic sentiments, expressed in the active collection of donations, the arrangement of hospitals, and the sending of military ambulance trains to the front. However, the patriotic outburst, which manifested itself clearly at the beginning of the war, was re-placed, first by openly expressed discontent, and subsequently by a revolutionary outburst in the province, which the authorities managed to suppress with great difficulty. Conclusion dwells upon the fact that the course of hostilities in the Russo-Japanese War of 1904–1905 was projected by the population on their own relations with the authorities and found a mirror image in the imperial hinterland.

A Multifaceted Competitive Zn–Cu Battery Unleashed by Optimizing Charge Protocols

AbstractRechargeable alkaline Zn–Cu batteries show great potential for energy storage systems due to their high capacity, cost‐effectiveness, and environmental‐friendliness. However, restricted by the severe dissolution upon charging, rapid capacity decline occurs throughout the cycle. Herein, the charging protocol is adjusted to bypass the dissolution stage of high‐valent states, thereby preserving the optimal reaction section of Zn–Cu batteries and greatly improving cycling stability. Additionally, a self‐activation process in the initial stage led to the spontaneous transformation of the original electroplated Cu particles on nickel foam from 10 to 4 mm, enhancing both conductivity and mass transfer, ultimately increasing the utilization of active materials. The battery achieved a discharge capacity of 349.5 mAh g−1, an ultra‐flat charge–discharge voltage platform, over 92% energy efficiency, a low cost of only $43.25 per kWh, and an exceptionally stable cyclic performance with no noticeable decay over 400 cycles. These 5D improvements position the Cu electrode as a robust candidate for the positive electrode material in the next generation of commercial Zn batteries.

COMPARISON OF THE PHENOLIC COMPOUNDS CONTENT AND COMPOSITION IN SYNECHOCYSTIS SP. AND DESERTIFILUM THARENSE

The content and composition of phenolic compounds in Synechocystis sp. PCC 6803 GT-L and Desertifilum tharense were studied for the first time. A spectrophotometric method was used to determine the phenolic compounds content, thin-layer chromatography and UV spectrometry to study their composition. A higher accumulation of these secondary metabolites was found in Synechocystis sp., which was almost twice as high as that in Desertifilum tharense. In both cases, the higher content of phenolic compounds was observed in the linear phase of cyanobacteria growth (3 days). Synechocystis sp. and Desertifilum tharense characterized by the formation of phenolics (4 and 7 compounds, respectively), which contain p-oxybenzoic or p-coumaric acids – the initial stages’metabolites of the phenolic compounds biogenesis.

Modeling and coupling analysis of enhanced coalbed methane recovery by gas injection

AbstractEnhanced coalbed methane (ECBM) recovery by gas injection is regarded as a feasible method for ECBM recovery. To investigate the mechanism of CH4 displacement by N2 injection, a series of physical experiments were conducted in the laboratory under different N2 injection pressures. The experimental results showed a continuous increase in the N2 volume fraction and a decrease in the CH4 volume fraction with the N2 injection pressure. The CH4 displacement efficiency increases rapidly in the initial stage and then gradually stabilizes. Given the effect of matrix shrinkage and effective stress on coal permeability, a dynamic multi‐field coupling model of ECBM recovery by N2 injection (N2‐ECBM) was proposed in this work. Then, numerical simulations were implemented by the coupling model to analyze the key factors affecting coal permeability, N2 injection pressure and CH4 pressure during the N2–ECBM process. Furthermore, the Response Surface Methodology (RSM) was used to investigate the interactions of multiple factors, the results reveal that an increase in one factor would weaken the influence of another factor. In addition, a RSM regression model was obtained and verified by the experimental data, with a well‐fitting outcomes. Therefore, the RSM model can be used in practical engineering applications to optimize specific extraction parameters for ECBM recovery at minimum cost in a limited extraction period.