A graph neural network-based stock forecasting method utilizing multi-source heterogeneous data fusion.

The study of the prediction of stock market volatility is of great significance to rationally control financial market risks and increase excessive investment returns and has received extensive attention from academic and commercial circles. However, as a dynamic and complex system, the stock market is affected by multiple factors and has a comprehensive capability to include complex financial data. Given that the explanatory variables of influencing factors are diverse, heterogeneous and complex, the existing intelligent algorithms have great limitations for the analysis and processing of multi-source heterogeneous data in the stock market. Therefore, this study adopts the edge weight and information transmission mechanism suitable for subgraph data to complete node screening, the gate recurrent unit (GRU) and long short-term memory (LSTM) to aggregate subgraph nodes. The compiled data contain the metapaths of three types of index data, and the introduction of the association relationship attention dimension effectively mines the implicit meanings of multi-source heterogeneous data. The metapath attention mechanism is combined with a graph neural network to complete the classification of multi-source heterogeneous graph data, by which the prediction of stock market volatility is realized. The results show that the above method is feasible for the fusion of heterogeneous stock market data and the mining of implicit semantic information of association relations. The accuracy of the proposed method for the prediction of stock market volatility in this study is 16.64% higher than that of the dimensional reduction index and 14.48% higher than that of other methods for the fusion and prediction of heterogeneous data using the same model.

IL-17 in intervertebral disc degeneration: Mechanistic insights and therapeutic implications.

Intervertebral disc degeneration (IDD) serves as an independent risk factor for lower back pain and is closely associated with spinal musculoskeletal disorders, including lumbar disc herniation, radiculopathy, and myelopathy. Interleukin-17 (IL-17), also named IL-17A, is a critical signature cytokine of T-helper 17 cells. Upon binding to the IL-17 receptor A/C heterodimeric complex, IL-17 can trigger multiple signal transduction pathways to stimulate gene transcription and increase messenger RNA stability. IL-17 expression is significantly increased in degenerative disc tissue and shows a positive correlation with disease severity. IL-17 has been shown to accelerate the development of IDD by promoting extracellular matrix degradation, enhancing inflammatory response, inducing neoangiogenesis, and inhibiting nucleus pulposus cell autophagy and proliferation. Targeting IL-17 represents a novel and promising approach for the therapeutic intervention of IDD. In this review, we summarized the recent progression about the role of IL-17 in IDD and highlighted its therapeutic implications.

The Effect of Molecular Isomerism on the Barrier Properties of Polyimides: Perspectives from Experiments and Simulations.

A novel carbazole-containing diamine (M-2,7-CPDA) isomer of our previously reported diamine 2,7-CPDA, has been synthesized using a two-step synthesis. Compared with 2,7-CPDA, the substituted position of amino is changed from para to meta for M-2,7-CPDA. The two diamines were polymerized with pyromellitic dianhydride (PMDA) to prepare two isomeric polyimides (M-2,7-CPPI and 2,7-CPPI), respectively. The effects of para/meta isomerism on microstructures and gas barrier performances of the two isomeric polyimides were studied by positron annihilation test, X-ray diffraction and molecular simulation. The results display that meta-connected M-2,7-CPPI has less ordered chain structure and weaker hydrogen bonding than para-connected 2,7-CPPI, which leads to loose chain stacking and thereby increased free volumes of M-2,7-CPPI. The higher free volumes promote the solubility and diffusivity of gas in M-2,7-CPPI. As a result, the meta-linked M-2,7-CPPI shows a lower gas barrier than its para-linked analog. The work provides guidance for the design and synthesis of high-performance barrier polymers.

Impact of Backbone Amide Substitution at the Meta- and Para-Positions on the Gas Barrier Properties of Polyimide.

This study designed and synthesised a meta-amide-substituted dianiline monomer (m-DABA) as a stereoisomer of DABA, a previously investigated para-amide-substituted dianiline monomer. This new monomer was polymerised with pyromellitic dianhydride (PMDA) to prepare a polyimide film (m-DABPI) in a process similar to that employed in a previous study. The relationship between the substitution positions on the monomer and the gas barrier properties of the polyimide film was investigated via molecular simulation, wide-angle X-ray diffraction (WXRD), and positron annihilation lifetime spectroscopy (PALS) to gain deeper insights into the gas barrier mechanism. The results showed that compared with the para-substituted DABPI, the m-DABPI exhibited better gas barrier properties, with a water vapour transmission rate (WVTR) and an oxygen transmission rate (OTR) as low as 2.8 g·m-2·d-1 and 3.3 cm3·m-2·d-1, respectively. This was because the meta-linked polyimide molecular chains were more tightly packed, leading to a smaller free volume and lower molecular chain mobility. These properties are not conducive to the permeation of small molecules into the film; thus, the gas barrier properties were improved. The findings have significant implications for the structural design of high-barrier materials and could promote the development of flexible display technology.

Structure-Gas Barrier Property Relationship in a Novel Polyimide Containing Naphthalene and Amide Groups: Evaluation by Experiments and Simulations.

In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized. Results show that the NAPPI exhibits superior barrier properties with extremely low water vapor and oxygen transmission rate values of 0.14 g·m-2·day-1 and 0.04 cm3·m-2·day-1, respectively. In addition, the NAPPI presents outstanding mechanical properties and thermal stability as well. This article attempts to explore the relationship between NAPPI structure and barrier properties by combining experiment and simulation. Studies on positron annihilation lifetime spectroscopy, Wide angle X-ray diffractograms and molecular dynamics simulations prove that the NAPPI has smaller interplanar spacing and higher chain regularity. In addition, the strong chain rigidity and interchain cohesion of NAPPI due to the presence of the rigid naphthalene ring and a large number of hydrogen bond interactions formed by amide groups result in compact chain packing and smaller free volume, which reduces the solubility and diffusibility of small molecules in the matrix. In general, the simulation results are consistent with the experimental results, which are important for understanding the barrier mechanism of NAPPI.

Structure and Gas Barrier Properties of Polyimide Containing a Rigid Planar Fluorene Moiety and an Amide Group: Insights from Molecular Simulations.

A novel diamine (FAPDA) bearing rigid planar fluorene and amide groups was successfully synthesized. Using such diamine and pyromellitic dianhydride (PMDA), a high-barrier polyimide (FAPPI) was obtained. FAPPI exhibits an outstanding gas barrier. Its water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) are as low as 0.51 g·m-2·day-1 and 0.43 cm3·m-2·day-1, respectively. Additionally, FAPPI shows excellent thermal stability with a coefficient of thermal expansion (CTE) of 5.8 ppm·K-1 and a glass transition temperature (T g) of 416 °C. Molecular simulations, positron annihilation, and X-ray diffraction were utilized to gain insight on the microstructures for the enhanced barrier properties. Introducing fluorene moieties and amide groups improves the regularity and rigidity of molecular chains and increases interchain interaction of PI, resulting in low free volumes and decreased movement capacity of the chain. The low free volumes of FAPPI restrain the gas diffusivity and solubility. Meanwhile, the decreased chain movement reduces the diffusivity of gases. Consequently, barrier performances of FAPPI are improved. The polyimide possesses widespread application in the microelectronics packaging fields.

Comprehensive analysis of N6-methyladenosine (m6A) modification during the degeneration of lumbar intervertebral disc in mice.

OBJECTIVE: To study the N6-methyladenosine (m6A) modification pattern of nucleus pulposus (NP) tissue during intervertebral disc degeneration (IDD). METHODS: A standing mouse model was generated, and staining and imaging methods were used to evaluate the IDD model. Methylated RNA immunoprecipitation with next-generation sequencing (MeRIP-seq) was used to analyze m6A methylation-associated transcripts in the NP, and real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of methylation-related enzymes and conduct bio-informatics analysis. RESULTS: The standing mouse model caused IDD. Continuous axial pressure changed the expression of related methylases in degenerated NP tissue. Relative to the control group, the expression levels of KIAA1429, METTL14, METTL3, METTL4, WTAP, DGCR8, EIF3A and YTHDC1 in the experimental group were higher, while those of FTO, ELAVL1, HNRNPC1 and SRSF2 were lower. We identified 985 differentially expressed genes through MeRIP-Seq, among which 363 genes were significantly up-regulated, and 622 genes were significantly down-regulated. In addition, among the 9648 genes counted, 1319 m6A peaks with significant differences in methylation were identified, among which 933 were significantly up-regulated, and 386 were significantly down-regulated. Genes and pathways that were enriched in IDD have been identified. CONCLUSION: The results of this study elucidated the m6A methylation pattern of NP tissue in degenerated lumbar intervertebral disc of mice and provided new perspectives and clues for research on and the treatment of lumbar disc degeneration. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: As one of the important causes of low back and leg pain, intervertebral disc degeneration brings a huge economic burden to the society, family and medical system. Therefore, understanding the molecular and cellular mechanisms of intervertebral disc degeneration is of great significance for guiding clinical treatment. In this study, methylated RNA immunoprecipitation with next-generation sequencing on mice lumbar nucleus pulposus tissues found that differentially expressed genes and changes in the expression of related methylases, confirming that RNA methylation is involved in intervertebral disc degeneration. The process provides new vision and clues for future research on intervertebral disc degeneration.

High-Barrier Polyimide Containing Carbazole Moiety: Synthesis, Gas Barrier Properties, and Molecular Simulations.

A high-barrier polyimide (2,7-CPI) was synthesized through the polymerization of pyromellitic dianhydride (PMDA) and a novel diamine (2,7-CDA) containing carbazole moiety. The synthesized diamine and polyimide were fully characterized by elemental analyses, FTIR and NMR. The 2,7-CPI displays very attractive barrier performances, with oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) low to 0.14 cm3·m-2·day-1 and 0.05 g·m-2·day-1, respectively. Meanwhile, 2,7-CPI also exhibits exceptional thermal stability with a glass transition temperature (Tg) of 467 °C, 5% weight-loss temperature (Td5%) of 550 °C under N2 and coefficient of thermal expansion (CTE) of 3.4 ppm/K. The barrier performances of 2,7-CPI are compared with those of a structural analogue (2,7-CPPI) and a typical polyimide (Kapton). Their barrier performances with respect to microstructure were investigated by molecular simulations, wide angle X-ray diffraction (WAXD), and positron annihilation lifetime spectroscopy (PALS). The results show that 2,7-CPI possesses better coplanar structure and more number of intermolecular hydrogen bonds among the three PIs, which result in tight chain packing and thereby high crystallinity, low free volume, and decreased chains mobility. That is, the high crystallinity and low free volume of 2,7-CPI reduce the diffusion and solubility of gases. Meanwhile, the poor chains mobility further decreases the gases diffusion. The reduced diffusion and solubility of gases consequently promote the improvement of barrier properties for 2,7-CPI. The polyimide has a wide application prospect in the field of flexible electronic packaging industries.

Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene-propylene-diene rubber.

Diffusion and sorption of five gases (H2, N2, O2, CO2, CH4) in hydrogenated nitrile butadiene rubber (HNBR) and ethylene-propylene-diene rubber (EPDM) have been investigated by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The diffusion coefficients of gas molecules in HNBR and EPDM are well correlated with the effective penetrant diameter except for CO2. CO2 shows a lower diffusion coefficient due to its linear shape. Additionally, the favorable interaction between CO2 and HNBR is another factor for its lower diffusion coefficient in HNBR. HNBR shows lower diffusion coefficients than EPDM. This is because the polar -CN groups in HNBR chains increase interchain cohesion and result in tight intermolecular packing, low free volume and poor chain mobility, which decreases the diffusion coefficients of HNBR. The solubility coefficients of CH4, O2, N2 and H2 in HNBR are lower than those in EPDM, which is a result of the weak HNBR-penetrant interactions and low free volume of HNBR. However, the solubility coefficient of CO2 in HNBR is higher than in EPDM. This is attributed to the strong interaction between CO2 and HNBR. H2, O2, N2 and CH4 show lower permeability coefficients in HNBR than in EPDM, while CO2 has higher permeability coefficients in HNBR. These molecular details provide critical information for the understanding of structures and gas transport between HNBR and EPDM.

Expression of microRNAs differed in the omental adipose tissue of obese rats.

OBJECTIVE: To establish obese rat models by high-fat diet, screen microRNAs by microarray in the omental adipose tissue, and find out differential expression of microRNAs in obese rats, for further understanding the role of microRNAs as regulating molecules in obesity-induced lipid metabolism disorders. METHODS: 40 male SD rats were randomly divided into normal diet group and high-fat diet group, respectively. After fed for 8 weeks, rats were weighted, measured length and other characteristics were observed. Eye blood was taken to test blood glucose level, blood lipids level, insulin level and other indicators. The omental adipose tissue was measured by electronic analytical scales and saved at -80°C liquid nitrogen. Fat cells were stained by oil red to observe their morphology under microscopy. The expression of microRNAs was screened by microarray, and verified by Real-Time PCR. RESULTS: After high-fat diet for 4 and 8 weeks, some fatty indicators changed, including increased body weight, omental fat weight, triglycerides, total cholesterol, low-density lipoprotein, blood glucose level and insulin level, and decreased high-density lipoprotein, and differential phenotype of fat cells. Besides, by microarray techniques and Real-Time PCR, 13 differential expression microRNAs were identified, including 7 up-regulated microRNAs (microRNA30a, microRNA7e, microRNA30c, microRNA335, microRNA103, microRNA107, microRNA139-5p), and 6 down-regulated microRNAs (microRNA494, microRNA140, microRNA342-5p, microRNA382, microRNA17-1-3p, microRNA92a). CONCLUSION: Changes in the expression of microRNAs contribute to the pathogenesis of many diseases, including obesity disorders. These alterations can be due to various mechanisms, such as cell proliferation, apoptosis, migration, and differentiation, providing new therapies for diseases.

Effect of rocuronium on the level and mode of pre-synaptic acetylcholine release by facial and somatic nerves, and changes following facial nerve injury in rabbits.

Muscles innervated by the facial nerve show differential sensitivities to muscle relaxants than muscles innervated by somatic nerves. The evoked electromyography (EEMG) response is also proportionally reduced after facial nerve injury. This forms the theoretical basis for proper utilization of muscle relaxants to balance EEMG monitoring and immobility under general anesthesia. (1) To observe the relationships between the level and mode of acetylcholine (ACh) release and the duration of facial nerve injury, and the influence of rocuronium in an in vitro rabbit model. (2) To explore the pre-synaptic mechanisms of discrepant responses to a muscle relaxant. Quantal and non-quantal ACh release were measured by using intracellular microelectrode recording in the orbicularis oris 1 to 42 days after graded facial nerve injury and in the gastrocnemius with/without rocuronium. Quantal ACh release was significantly decreased by rocuronium in the orbicularis oris and gastrocnemius, but significantly more so in gastrocnemius. Quantal release was reduced after facial nerve injury, which was significantly correlated with the severity of nerve injury in the absence but not in the presence of rocuronium. Non-quantal ACh release was reduced after facial nerve injury, with many relationships observed depending on the extent of the injury. The extent of inhibition of non-quantal release by rocuronium correlated with the grade of facial nerve injury. These findings may explain why EEMG amplitude might be diminished after acute facial nerve injury but relatively preserved after chronic injury and differential responses in sensitivity to rocuronium.

Pressure overload-induced cardiac hypertrophy response requires janus kinase 2-histone deacetylase 2 signaling.

Pressure overload induces cardiac hypertrophy through activation of Janus kinase 2 (Jak2), however, the underlying mechanisms remain largely unknown. In the current study, we tested whether histone deacetylase 2 (HDAC2) was involved in the process. We found that angiotensin II (Ang-II)-induced re-expression of fetal genes (Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP)) in cultured cardiomyocytes was prevented by the Jak2 inhibitor AG-490 and HDAC2 inhibitor Trichostatin-A (TSA), or by Jak2/HDAC2 siRNA knockdown. On the other hand, myocardial cells with Jak2 or HDAC2 over-expression were hyper-sensitive to Ang-II. In vivo, pressure overload by transverse aorta binding (AB) induced a significant cardiac hypertrophic response as well as re-expression of ANP and BNP in mice heart, which were markedly reduced by AG-490 and TSA. Significantly, AG-490, the Jak2 inhibitor, largely suppressed pressure overload-/Ang-II-induced HDAC2 nuclear exportation in vivo and in vitro. Meanwhile, TSA or HDAC2 siRNA knockdown reduced Ang-II-induced ANP/BNP expression in Jak2 over-expressed H9c2 cardiomyocytes. Together, these results suggest that HDAC2 might be a downstream effector of Jak2 to mediate cardiac hypertrophic response by pressure overload or Ang-II.