Quantitative classification evaluation model for tight sandstone reservoirs based on machine learning.

Tight sandstone reservoirs are a primary focus of research on the geological exploration of petroleum. However, many reservoir classification criteria are of limited applicability due to the inherent strong heterogeneity and complex micropore structure of tight sandstone reservoirs. This investigation focused on the Chang 8 tight reservoir situated in the Jiyuan region of the Ordos Basin. High-pressure mercury intrusion experiments, casting thin sections, and scanning electron microscopy experiments were conducted. Image recognition technology was used to extract the pore shape parameters of each sample. Based on the above, through grey relational analysis (GRA), analytic hierarchy process (AHP), entropy weight method (EWM) and comprehensive weight method, the relationship index Q1 between initial productivity and high pressure mercury injection parameters and the relationship index Q2 between initial productivity and pore shape parameters are obtained by fitting. Then a dual-coupled comprehensive quantitative classification prediction model for tight sandstone reservoirs was developed based on pore structure and shape parameters. A quantitative classification study was conducted on the target reservoir, analyzing the correlation between reservoir quality and pore structure and shape parameters, leading to the proposal of favourable exploration areas. The research results showed that when Q1 ≥ 0.5 and Q2 ≥ 0.5, the reservoir was classified as type I. When Q1 > 0.7 and Q2 > 0.57, it was classified as type I1, indicating a high-yield reservoir. When 0.32 < Q1 < 0.47 and 0.44 < Q2 < 0.56, was classified as type II. When 0.1 < Q1 < 0.32 and 0.3 < Q2 < 0.44, it was classified as type III. Type I reservoirs exhibit a zigzag pattern in the northwest part of the study area. Thus, the northwest should be prioritized in actual exploration and development. Additionally, the initial productivity of tight sandstone reservoirs showed a positive correlation with the porosity, permeability, sorting coefficient, coefficient of variation, and median radius. Conversely, it demonstrated a negative correlation with the median pressure and displacement pressure. The perimeters of pores, their circularity, and the length of the major axis showed a positive correlation with the porosity, permeability, sorting coefficient, coefficient of variation, and median radius. On the other hand, they exhibited a negative correlation with the median pressure and displacement pressure. This study quantitatively constructed a new classification and evaluation system for tight sandstone reservoirs from the perspective of microscopic pore structure, achieving an overall model accuracy of 93.3%. This model effectively predicts and evaluates tight sandstone reservoirs. It provides new guidance for identifying favorable areas in the study region and other tight sandstone reservoirs.

Effects of Dietary Lipid Levels on the Growth, Muscle Fatty Acid and Amino Acid Composition, Antioxidant Capacity, and Lipid Deposition in Mirror Carp (Cyprinus carpio).

In fish, increasing the crude lipid level of feed can save protein and improve feed utilization. Mirror carp (Cyprinus carpio) is one of the most widely farmed fish species in the world. In this study, mirror carp larvae were fed isonitrogenous diets with different lipid levels (3%, 5%, 7%, 9%, 11%, and 13%). The rearing trial lasted for eight weeks. The results revealed that when the fat content was 9%, the AWGR, WGR, and FCR were highest, whereas FCR was lowest. The AWGR was correlated with the dietary lipid level, and the regression equation was y = -2.312x2 + 45.01x + 214.49. Compared with those in the control group, the T-CHO and TG contents were significantly greater in the 13% lipid content groups and significantly lower in the 9% lipid content groups (p < 0.05). In terms of muscle quality, the contents of MUFAs, PUFAs, and DHA + EPA were significantly greater than those in the other experimental groups (p < 0.05). Oil red O staining revealed a lipid content of 13% with severe fat deposition. In addition, the results of the analysis of antioxidant enzyme activity revealed that the activities of GSH, CAT and T-AOC were significantly greater at the 9% lipid content, and that the MDA content was significantly greater at the 13% lipid content (p < 0.05). Similarly, the mRNA levels of GH, IGF-I, FAS, and LPL were significantly highest at a lipid level of 9% (p < 0.05). The above results revealed that the optimal dietary lipid requirement for the fast growth of mirror carp (6.86 ± 0.95 g) was 9.74% on the basis of nonlinear regression analysis of the AWGR. The dietary lipid level (9%) improved the growth, stress resistance, and lipid utilization of mirror carp to a certain extent.

Research into Prediction Method for Pressure Pulsations in a Centrifugal Pump Based on Variational Mode Decomposition-Particle Swarm Optimization and Hybrid Deep Learning Models.

Centrifugal pump pressure pulsation contains various signals in different frequency domains, which interact and superimpose on each other, resulting in characteristics such as intermittency, non-stationarity, and complexity. Computational Fluid Dynamics (CFD) and traditional time series models are unable to handle nonlinear and non-smooth problems, resulting in low accuracy in the prediction of pressure fluctuations. Therefore, this study proposes a new method for predicting pressure fluctuations. The pressure pulsation signals at the inlet of the centrifugal pump are processed using Variational Mode Decomposition-Particle Swarm Optimization (VMD-PSO), and the signal is predicted by Convolutional Neural Networks-Long Short-Term Memory (CNN-LSTM) model. The results indicate that the proposed prediction model combining VMD-PSO with four neural networks outperforms the single neural network prediction model in terms of prediction accuracy. Relatively high accuracy is achieved by the VMD-PSO-CNN-LSTM model for multiple forward prediction steps, particularly for a forward prediction step of 1 (Pre = 1), with a root mean square error of 0.03145 and an average absolute percentage error of 1.007%. This study provides a scientific basis for the intelligent operation of centrifugal pumps.

IRF9 inhibits CyHV-3 replication by regulating the PI3K-AKT signalling pathway in common carp (Cyprinus carpio) epithelial cells.

Interferon regulatory factor 9 (IRF9) is an important transcriptional regulator involved in innate and adaptive immunity. Cyprinid herpesvirus-3 (CyHV-3) is a virus causing widespread death and great economic loss in farmed common carp (Cyprinus carpio). However, the effect of IRF9 on CyHV-3 infection in common carp has not been reported. In this study, during CyHV-3 infection, IRF9 overexpression in common carp fin epithelial (CCF) cells significantly reduced the expression of viral factor thymidine kinase (TK) and open reading frame 72 (ORF72), and knockdown of IRF9 produced the opposite results (p < 0.05). In CCF cells. The IRF9 protein was expression in the nucleus and was rapidly induced in CCF cells by CyHV-3 infection. In addition, several genes associated with virus infection, including type I interferon (IFNI), IFN-stimulated gene 15 (ISG15), myxovirus resistance 1 (Mx1) and Viperin were induced in CCF cells overexpressing IRF9 upon CyHV-3 infection. IRF9 overexpression induced by CyHV-3 infection significantly increased the gene expression of Mx1 and phosphoinositide 3-kinase (PI3K) and the protein expression of protein kinase B (AKT) (p < 0.01). Interestingly, IRF9 did not significantly affect Mx1 gene expression when AKT protein levels remained unchanged during CyHV-3 infection of CCF cells. Furthermore, a significant resistance-related locus was found in the IRF9 sequence in "Longke-11" mirror carp (M11) and Yellow River carp (p < 0.05). These results indicated that IRF9 inhibited viral replication by upregulating the expression of Mx1 via the PI3K-AKT signalling pathway during CyHV-3 infection in CCF cells and provide some basis for the study of the antiviral molecular mechanisms of common carp.

Effects of Different Dietary Protein Levels on the Growth Performance, Physicochemical Indexes, Quality, and Molecular Expression of Yellow River Carp (Cyprinus carpio haematopterus).

A 12-week rearing trial was carried out to estimate effects on the growth performance, physicochemical indexes, quality, and the molecular expression of Yellow River Carp (Cyprinus carpio haematopterus) using five practical diets, including dietary protein levels of 220, 250, 280, 310, and 340 g/kg. The results illustrated that the fish's weight gain (WG) and specific growth rate (SGR) were significantly influenced, with an ascending dietary protein level of up to 250 g/kg (p < 0.05). The carp muscle contents of total saturated fatty acids (∑SFA), monounsaturated fatty acids (∑MUFA), polyunsaturated fatty acids (∑PUFA), and fatty acids (∑FA) decreased significantly with the ascending dietary protein levels, except for the 250 g/kg protein diet (p < 0.05). Only the glutamic acid and total essential amino acid (∑EAA) contents were significantly influenced by the ascending dietary protein levels (p < 0.05). The relative GH expression of the carp muscle significantly decreased with the increase in the dietary protein level up to 310 g/kg, and then it significantly increased (p < 0.05). In the intestines, the peak relative TOR expression was observed on the 220 g/kg protein diet, while the relative 4EBP1 expression was significantly influenced by the dietary protein level up to 250 g/kg (p < 0.05). In the muscle, the peak relative TOR and 4EBP1 expression levels were observed on the 250 g/kg protein diet. In gills, the lowest relative Rhag, Rhbg, and Rhcg1 expression levels were observed on the 250 g/kg protein diet. Based on all of the aforementioned results, the optimal dietary protein level for Cyprinus carpio haematopterus (160.24 ± 15.56 g) is 250-280 g/kg.

Integrative Transcriptomic Analysis Reveals the Immune Mechanism for a CyHV-3-Resistant Common Carp Strain.

Anti-disease breeding is becoming the most promising solution to cyprinid herpesvirus-3 (CyHV-3) infection, the major threat to common carp aquaculture. Virus challenging studies suggested that a breeding strain of common carp developed resistance to CyHV-3 infection. This study illustrates the immune mechanisms involved in both sensitivity and anti-virus ability for CyHV3 infection in fish. An integrative analysis of the protein-coding genes and long non-coding RNAs (lncRNAs) using transcriptomic data was performed. Tissues from the head kidney of common carp were extracted at days 0 (the healthy control) and 7 after CyHV-3 infection (the survivors) and used to analyze the transcriptome through both Illumina and PacBio sequencing. Following analysis of the GO terms and KEGG pathways involved, the immune-related terms and pathways were merged. To dig out details on the immune aspect, the DEGs were filtered using the current common carp immune gene library. Immune gene categories and their corresponding genes in different comparison groups were revealed. Also, the immunological Gene Ontology terms for lncRNA modulation were retained. The weighted gene co-expression network analysis was used to reveal the regulation of immune genes by lncRNA. The results demonstrated that the breeding carp strain develops a marked resistance to CyHV-3 infection through a specific innate immune mechanism. The featured biological processes were autophagy, phagocytosis, cytotoxicity, and virus blockage by lectins and MUC3. Moreover, the immune-suppressive signals, such as suppression of IL21R on STAT3, PI3K mediated inhibition of inflammation by dopamine upon infection, as well as the inhibition of NLRC3 on STING during a steady state. Possible susceptible factors for CyHV-3, such as ITGB1, TLR18, and CCL4, were also revealed from the non-breeding strain. The results of this study also suggested that Nramp and PAI regulated by LncRNA could facilitate virus infection and proliferation for infected cells respectively, while T cell leukemia homeobox 3 (TLX3), as well as galectin 3 function by lncRNA, may play a role in the resistance mechanism. Therefore, immune factors that are immunogenetically insensitive or susceptible to CyHV-3 infection have been revealed.

Characterization of the mitochondrial genome of Megalobrama terminalis in the Heilong River and a clearer phylogeny of the genus Megalobrama.

Megalobrama terminalis distributed in Sino-Russian Heilong-Amur River basin has decreased dramatically in the last few decades. It has been listed in the Red Book of the Russian Federation as an endangered fish species. Here, the complete mitochondrial (mt) genome sequence of M. terminalis in the Heilong River (MTH) was first determined and characterized. Additionally, we identified a population-specific single nucleotide polymorphism (SNP) locus in MTH which could effectively separate MTH from the six other populations of the genus Megalobrama in the absence of hybridization. Moreover, phylogenetic analyses determined that the Xi River M. hoffmanni is located at the basal branch of the clade, and the rest of the group is divided into two assemblages, namely, one containing M. terminalis from Qiantang River and Jinsha River Reservoir/Longxi River M. Pellegrini/MTH and the other containing M. amblycephala from Liangzi Lake and Yi River. We clarify the intraspecies identity of MTH and construct a clearer phylogeny of the genus Megalobrama, which will contribute to the germplasm identification, protection and development of MTH in the future.