Study of Preparation and Properties of Stereoregular Poly(cyclohexenylene carbonate).

Fixing carbon dioxide as a polymer material is an effective and environmentally beneficial approach for reducing the harm of CO2 greenhouse gas. In this paper, carbon dioxide and cyclohexene oxide were used as co-monomers, and a chiral binuclear cobalt complex with a biphenyl linker was employed as the catalyst to successfully prepare a poly(cyclohexenylene carbonate) with high stereoregularity. The influence of catalyst structure, CO2 pressure, and operating temperature on the copolymerization rate and polymer structure were systematically investigated. Optimal catalyst structure and operating conditions were determined, resulting in an excellent poly(cyclohexenylene carbonate) with a stereoregularity as high as 93.5%. Performance testing revealed that the polyester had a molecular weight of approximately 20 kg/mol, a glass transition temperature of 129.7 °C, an onset decomposition temperature of 290 °C, and a tensile strength of 42.8 MPa. These results demonstrate high thermal stability and mechanical strength, indicating the potential for expanding the applications of aliphatic polycarbonate materials.

Postsystolic shortening and early systolic lengthening for early detection of myocardial involvement in patients with systemic lupus erythematosus.

BACKGROUND: Cardiac involvement predicts a poor prognosis in patients with systemic lupus erythematosus (SLE). Two-dimensional speckle-tracking echocardiography (2D-STE) are used to identify subclinical myocardial involvement in various diseases. This study objected to evaluate postsystolic shortening (PSS) and early systolic lengthening (ESL) by 2D-STE for early detection of myocardial involvement in patients with SLE. METHODS: A total of 121 patients with preserved left ventricular ejection fraction (LVEF) in SLE and 30 healthy controls underwent standard 2D-STE in our study. According to SLE disease activity index (SLEDAI), we divided SLE patients into two groups: the group of inactive disease (SLEDAI ≤ 4) and active disease (SLEDAI ≥ 5). The maximum of postsystolic strain index (PSImax ) and early systolic strain index (ESImax ) were acquired from 17 segments of left ventricular (LV). We also compared the PSImax and ESImax of basal, medial, and apical segments between SLE patients and controls. RESULTS: Compared with healthy controls and the group of SLEDAI ≤ 4, the group of SLEDAI ≥ 5 had higher PSImax and ESImax value of global LV and basal segments. The absolute value of global longitudinal strain (GLS) had no difference between the group of active disease and inactive disease. Multivariate analysis demonstrated that PSS was independently associated with SLEDAI and diabetes mellitus. CONCLUSIONS: Detection of PSS and ESL enable to identify LV systolic impairment in SLE patients at an early stage.

A stacked self-attention network for two-dimensional direction-of-arrival estimation in hands-free speech communication.

When making voice interactions with hands-free speech communication devices, direction-of-arrival estimation is an essential step. To address the detrimental influence of unavoidable background noise and interference speech on direction-of-arrival estimation, this paper introduces a stacked self-attention network system, a supervised deep learning method that enables utterance level estimation without requirement for any pre-processing such as voice activity detection. Specifically, alternately stacked time- and frequency-dependent self-attention blocks are designed to process information in terms of time and frequency, respectively. The former blocks focus on the importance of each time frame of the received audio mixture and perform temporal selection to reduce the influence of non-speech and interference frames, while the latter blocks are utilized to derive inner-correlation among different frequencies. Additionally, the non-causal convolution and self-attention networks are replaced by causal ones, enabling real-time direction-of-arrival estimation with a latency of only 6.25 ms. Experiments with simulated and measured room impulse responses, as well as real recordings, verify the advantages of the proposed method over the state-of-the-art baselines.

Long-term scalogram integrated with an iterative data augmentation scheme for acoustic scene classification.

In acoustic scene classification (ASC), acoustic features play a crucial role in the extraction of scene information, which can be stored over different time scales. Moreover, the limited size of the dataset may lead to a biased model with a poor performance for recordings from unseen cities and confusing scene classes. This paper proposes a long-term wavelet feature that captures discriminative long-term scene information. The extracted scalogram requires a lower storage capacity and can be classified faster and more accurately compared with classic Mel filter bank coefficients (FBank). Furthermore, a data augmentation scheme is adopted to improve the generalization of the ASC systems, which extends the database iteratively with auxiliary classifier generative adversarial neural networks (ACGANs) and a deep learning-based sample filter. Experiments were conducted on datasets from the Detection and Classification of Acoustic Scenes and Events (DCASE) challenges. The DCASE17 and DCASE19 datasets marked a performance boost of the proposed techniques compared with the FBank classifier. Moreover, the ACGAN-based data augmentation scheme achieved an absolute accuracy improvement of 6.10% on recordings from unseen cities, far exceeding classic augmentation methods.

Prior bariatric surgery and perioperative cardiovascular outcomes following noncardiac surgery in patients with type 2 diabetes mellitus: hint from National Inpatient Sample Database.

BACKGROUND: Both diabetes and obesity are risk factors for perioperative major adverse events. This study aims to evaluate the association between prior bariatric surgery (prior-BS) and perioperative cardiovascular outcomes following noncardiac surgery in patients with type 2 diabetes mellitus (T2DM). METHODS: We used the National Inpatient Sample Database to identify T2DM patients undergoing major noncardiac surgery from 2006 to 2014. The primary outcome was major perioperative adverse cardiovascular and cerebrovascular events (MACCEs), which include death, acute myocardial infarction and acute ischaemic stroke. In-hospital outcomes between patients with prior BS and morbid obesity were compared using unadjusted logistic, multivariable logistic and propensity score matching analyses. RESULTS: A weighted of 1,526,820 patients diagnosed with T2DM who underwent noncardiac surgery were included. The rates of both prior BS and morbid obesity significantly increased during the study period (P < 0.0001). Patients with prior BS were younger, were more likely to be female, and had lower rates of cardiovascular risk factors but had higher rates of smoking, alcohol abuse, anaemia, prior venous thromboembolism and prior percutaneous coronary intervention. The incidence of MACCEs was 1.01% and 3.25% in patients with prior BS and morbid obesity, respectively. After multivariable adjustment, we found that prior BS was associated with a reduced risk of MACCEs (odds ratio [OR] = 0.71; 95% confidence interval [CI] 0.62-0.81), death (OR = 0.64, 95% CI 0.52-0.78), acute kidney injury (OR = 0.66, 95% CI 0.62-0.70) and acute respiratory failure (OR: 0.46; 95% CI 0.42-0.50). CONCLUSIONS: Prior bariatric surgery in T2DM patients undergoing noncardiac surgery is associated with a lower risk of MACCEs. Prospective studies are needed to verify the benefits of bariatric surgery in patients undergoing noncardiac surgery.

A potyvirus isolated from Mirabilis jalapa in China represents a new species.

We previously reported a possible potyvirus isolated from Mirabilis jalapa that exhibited a high degree of sequence similarity to Basella rugose mosaic virus (BaRMV) in the region encoding the coat protein (CP). Here, we present the complete genome sequence of this isolate, comprising a 9666-nucleotide-long monopartite ssRNA (excluding the poly(A) tail) encoding a 3080-amino-acid polyprotein. The CP region showed a high degree of nucleotide sequence similarity to three BaRMV isolates (75.2-77.3% identity), while other regions showed nucleotide sequence identity values (48.8-73.7%) below the species demarcation threshold proposed by the ICTV. Therefore, we propose that this isolate be considered a new member of the genus Potyvirus, tentatively named "mirabilis crinkle mosaic virus" (MiCMV).

Exendin-4 modifies adipogenesis of human adipose-derived stromal cells isolated from omentum through multiple mechanisms.

BACKGROUND: Abdominal obesity is considered a major factor in the development of metabolic disorders. Glucagon-like peptide-1 (GLP-1) has been reported to have positive effects on improving body metabolism and to reducing insulin resistance. However, it remains less clear whether GLP-1 plays a role in the adipogenesis process of visceral fat. METHODS: Here, we analyzed the in vitro actions and probable mechanisms of Exendin-4, a GLP-1 receptor agonist, on human adipose-derived stromal cells (hADSCs) isolated from omentum. RESULTS: Our results demonstrated that Exendin-4 improved cell viability via promoting proliferation and inhibiting apoptosis in hADSCs isolated from omentum. Mechanistically, the activation of MAPK/ ERK1/2, Akt/GSK-3ß, and PKA/CREB pathways and downstream consequences induced are involved in the proliferative and anti-apoptotic roles of Exendin-4. More intriguingly, Exendin-4 could promote the differentiation of omental hADSCs. Underlying mechanisms of the differentiation of hADSCs are associated with the upregulation of the expression of pro-adipogenic genes and downregulation of the expression of anti-adipogenic genes. CONCLUSION: Our data demonstrate that Exendin-4 modifies adipogenesis of hADSCs isolated from omentum through multiple mechanisms, these effects could contribute to the protective actions of GLP-1 receptor agonist body metabolism and insulin sensitivity.

Polymorphisms of the Ras-Association Domain Family 1 Isoform A (RASSF1A) Gene are Associated with Ovarian Cancer, and with the Prognostic Factors of Grade and Stage, in Women in Southern China.

BACKGROUND The aim of this study was to determine whether polymorphisms of the Ras-association domain family 1 isoform A (RASSF1A) gene were associated with ovarian cancer and with tumor grade and stage, which affect the prognosis of ovarian cancer, in women in Southern China. MATERIAL AND METHODS Women from Southern China with histologically confirmed, graded and staged ovarian cancer (n=1,375), and cancer-free controls (n=1,227), provided samples of peripheral blood. DNA was extracted from the blood samples, and five tagging single nucleotide polymorphisms (SNPs) (rs4688728G>T, rs72932987C>T, rs1989839C>T, rs2073497A>C, and rs2236947A>C) were evaluated using an online assay-by-design platform. Polymerase chain reaction (PCR) DNA amplification was performed and computational haplotyping analysis of genetic associations between the five tagging SNPs was performed to identify frequent haplotypes in women with ovarian cancer, and the associations with tumor grade and stage. RESULTS In women in Southern China, the CT genotype of rs1989839 was associated with the patients with ovarian cancer (P=0.001), and was significantly correlated with tumor grade and stage (P=0.008). One of the remaining four SNPs studied, rs2073497A>C showed an association with the prognostic factors of grade and stage, but this association did not reach statistical significance. CONCLUSIONS Polymorphisms of the RASSF1A gene, most significantly the CT genotype of rs1989839, might play a role in the development and prognosis of ovarian cancer in women in Southern China. To our knowledge, this is the first study to demonstrate an association between polymorphisms in the RASSF1A gene in ovarian cancer.

Transmurally differentiated measurement of ATP hydrolysis rates in the in vivo porcine hearts.

PURPOSE: Compare the transmural distribution of forward creatine kinase reaction (kf,CK ) and ATP hydrolysis rate (kr,ATPase ) in the myocardium of normal porcine heart. Rate constants were extracted from partially relaxed spectra by applying the T1nom method, effectively reducing data acquisition time by up to an order of magnitude. THEORY AND METHODS: T1nom method for double saturation of PCr and Pi is introduced and validated through simulations. Bioenergetics was measured in vivo utilizing one-dimensional chemical shift imaging (1D-CSI) magnetic resonance (31) P spectroscopy. RESULTS: At basal conditions, there was no significant difference between subepicardial layers (EPI) vs. the subendocardial layers (ENDO) for both fluxf,CK and fluxr,ATPase . At high cardiac workload (HWL), where the rate pressure product increased 2.6-fold, PCr/ATP ratio and fluxf,CK showed no significant change in both EPI and ENDO layers, while fluxr,ATPase increased significantly (baseline: 1.11 ± 0.12 and 1.12 ± 0.13 µmol/g/s, EPI and ENDO, respectively; to HWL: 2.35 ± 0.27 and 2.21 ± 0.08 µmol/g/s, EPI and ENDO, respectively, each P < 0.01 vs. baseline). CONCLUSION: In the normal heart, increase of cardiac work state is accompanied by an increase in ATP hydrolysis rate with no changes in CK flux rate. There are no significant differences between EPI vs. ENDO concerning the ATP hydrolysis rate or CK flux rate in both baseline and high cardiac work states.

Complete genome sequence of yam chlorotic necrotic mosaic virus from Dioscorea parviflora.

The complete genome sequence of yam chlorotic necrotic mosaic virus (YCNMV) was determined. It is a monopartite ssRNA 8208 nucleotides in length (excluding the poly(A) tail) and encoding a polyprotein of 2622 amino acids. Sequence analysis showed that the P1 region and some conserved motifs, such as the typical potyvirus aphid-transmission motifs DAG, PTK and KITC, are absent. Phylogenetic analysis based on the complete polyprotein sequences of YCNMV and selected members of the family Potyviridae clearly showed that this virus should be assigned to the genus Macluravirus and suggest that YCNMV is a new member of the genus Macluravirus.

Myocardial ATP hydrolysis rates in vivo: a porcine model of pressure overload-induced hypertrophy.

Left ventricular (LV) hypertrophy (LVH) and congestive heart failure are accompanied by changes in myocardial ATP metabolism. However, the rate of ATP hydrolysis cannot be measured in the in vivo heart with the conventional techniques. Here, we used a double-saturation phosphorous-31 magnetic resonance spectroscopy-magnetization saturation transfer protocol to monitor ATP hydrolysis rate in swine hearts as the hearts became hypertrophic in response to aortic banding (AOB). Animals that underwent AOB (n = 22) were compared with animals that underwent sham surgery (n = 8). AOB induced severe LVH (cardiac MRI). LV function (ejection fraction and systolic thickening fraction) declined significantly, accompanied by deferent levels of pericardial effusion, and wall stress increased in aorta banded animals at week 1 after AOB, suggesting acute heart failure, which recovered by week 8 when concentric LVH restored LV wall stresses. Severe LV dysfunction was accompanied by corresponding declines in myocardial bioenergetics (phosphocreatine-to-ATP ratio) and in the rate of ATP production via creatine kinase at week 1. For the first time, the same linear relationships of the rate increase of the constants of the ATP hydrolysis rate (kATP→Pi) vs. the LV rate-pressure product increase during catecholamine stimulation were observed in vivo in both normal and LVH hearts. Collectively, these observations demonstrate that the double-saturation, phosphorous-31 magnetic resonance spectroscopy-magnetization saturation transfer protocol can accurately monitor myocardial ATP hydrolysis rate in the hearts of living animals. The severe reduction of LV chamber function during the acute phase of AOB is accompanied by the decrease of myocardial bioenergetic efficiency, which recovers as the compensated LVH restores the LV wall stresses.

Thymosin ß4 increases the potency of transplanted mesenchymal stem cells for myocardial repair.

BACKGROUND: Thymosin ß4 (Tß4) has been shown to enhance the survival of cultured cardiomyocytes. Here, we investigated whether the cytoprotective effects of Tß4 can increase the effectiveness of transplanted swine mesenchymal stem cells (sMSCs) for cardiac repair in a rat model of myocardial infarction (MI). METHODS AND RESULTS: Under hypoxic conditions, cellular damage (lactate dehydrogenase leakage), apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labelingc cells), and caspase-8 activity were significantly lower, whereas B-cell lymphoma-extra large protein expression was significantly higher, in sMSCs cultured with Tß4 (1 µg/mL) than in sMSCs cultured without Tß4, and Tß4 also increased sMSC proliferation. For in vivo experiments, animals were treated with basal medium (MI: n=6), a fibrin patch (Patch: n=6), a patch containing sMSCs (sMSC: n=9), or a patch containing sMSCs and Tß4 (sMSC/Tß4: n=11); Tß4 was encapsulated in gelatin microspheres to extend Tß4 delivery. Four weeks after treatment, echocardiographic assessments of left-ventricular ejection fraction and fractional shortening were significantly better (P<0.05) in sMSC/Tß4 animals (left-ventricular ejection fraction=51.7 ± 1.1%; fractional shortening=26.7 ± 0.7%) than in animals from MI (39 ± 3%; 19.5 ± 1.7%) and Patch (43 ± 1.4%; 21.6 ± 0.9%) groups. Histological assessment of infarct wall thickness was significantly higher (P<0.05) in sMSC/Tß4 animals (50%, [45%, 80%]) than in animals from MI (25%, [20%, 25%]) group. Measurements in sMSC (left-ventricular ejection fraction=45 ± 2.6%; fractional shortening=22.9 ± 1.6%; TH = 43% [25%, 45%]), Patch, and MI animals were similar. Tß4 administration also significantly increased vascular growth, the retention/survival of the transplanted sMSCs, and the recruitment of endogenous c-Kit(+) progenitor cells to the infarcted region. CONCLUSIONS: Extended-release Tß4 administration improves the retention, survival, and regenerative potency of transplanted sMSCs after myocardial injury.

Functional consequences of human induced pluripotent stem cell therapy: myocardial ATP turnover rate in the in vivo swine heart with postinfarction remodeling.

BACKGROUND: The use of cells derived from human induced pluripotent stem cells as cellular therapy for myocardial injury has yet to be examined in a large-animal model. METHODS AND RESULTS: Immunosuppressed Yorkshire pigs were assigned to 1 of 3 groups: A myocardial infarction group (MI group; distal left anterior descending coronary artery ligation and reperfusion; n=13); a cell-treatment group (MI with 4×10(6) vascular cells derived from human induced pluripotent stem cells administered via a fibrin patch; n=14); and a normal group (n=15). At 4 weeks, left ventricular structural and functional abnormalities were less pronounced in hearts in the cell-treated group than in MI hearts (P<0.05), and these improvements were accompanied by declines in scar size (10.4±1.6% versus 8.3±1.1%, MI versus cell-treatment group, P<0.05). The cell-treated group displayed a significant increase in vascular density and blood flow (0.83±0.11 and 1.05±0.13 mL·min(-1)·g(-1), MI versus cell-treatment group, P<0.05) in the periscar border zone (BZ), which was accompanied by improvements in systolic thickening fractions (infarct zone, -10±7% versus 5±5%; BZ, 7±4% versus 23±6%; P<0.05). Transplantation of vascular cells derived from human induced pluripotent stem cells stimulated c-kit(+) cell recruitment to BZ and the rate of bromodeoxyuridine incorporation in both c-kit(+) cells and cardiomyocytes (P<0.05). Using a magnetic resonance spectroscopic saturation transfer technique, we found that the rate of ATP hydrolysis in BZ of MI hearts was severely reduced, and the severity of this reduction was linearly related to the severity of the elevations of wall stresses (r=0.82, P<0.05). This decline in BZ ATP utilization was markedly attenuated in the cell-treatment group. CONCLUSIONS: Transplantation of vascular cells derived from human induced pluripotent stem cells mobilized endogenous progenitor cells into the BZ, attenuated regional wall stress, stimulated neovascularization, and improved BZ perfusion, which in turn resulted in marked increases in BZ contractile function and ATP turnover rate.

Bioenergetic and functional consequences of cellular therapy: activation of endogenous cardiovascular progenitor cells.

RATIONALE: The mechanism by which endogenous progenitor cells contribute to functional and beneficial effects in stem cell therapy remains unknown. OBJECTIVE: Utilizing a novel (31)P magnetic resonance spectroscopy-2-dimensional chemical shift imaging method, this study examined the heterogeneity and bioenergetic consequences of postinfarction left ventricular (LV) remodeling and the mechanisms of endogenous progenitor cell contribution to the cellular therapy. METHODS AND RESULTS: Human embryonic stem cell-derived vascular cells (hESC-VCs) that stably express green fluorescent protein and firefly luciferase (GFP(+)/Luc(+)) were used for the transplantation. hESC-VCs may release various cytokines to promote angiogenesis, prosurvival, and antiapoptotic effects. Both in vitro and in vivo experiments demonstrated that hESC-VCs effectively inhibit myocyte apoptosis. In the mouse model, a fibrin patch-based cell delivery resulted in a significantly better cell engraftment rate that was accompanied by a better ejection fraction. In the swine model of ischemia-reperfusion, the patch-enhanced delivery of hESC-VCs resulted in alleviation of abnormalities including border zone myocardial perfusion, contractile dysfunction, and LV wall stress. These results were also accompanied by a pronounced recruitment of endogenous c-kit(+) cells to the injury site. These improvements were directly associated with a remarkable improvement in myocardial energetics, as measured by a novel in vivo (31)P magnetic resonance spectroscopy-2-dimensional chemical shift imaging technology. CONCLUSIONS: The findings of this study demonstrate that a severely abnormal heterogeneity of myocardial bioenergetics in hearts with postinfarction LV remodeling can be alleviated by the hESC-VCs therapy. These findings suggest an important therapeutic target of peri-scar border zone and a promising therapeutic potential for using hESC-VCs together with the fibrin patch-based delivery system.

A review of existing methods for predicting leachate production from municipal solid waste landfills.

Landfilling is one of the predominant methods of municipal solid waste (MSW) disposal worldwide, while the generation of leachate, a kind of toxic wastewater, is among the primary factors behind landfill instability and environmental contamination problems. Precise prediction of leachate production is crucial to landfill safety evaluation and design. This paper presents a comprehensive review of methods for predicting leachate production from MSW landfills. Firstly, compositional characteristics of MSW and leachate generation mechanism are analysed. Factors influencing leachate production are summarised based on the generation mechanism, including the components of MSW, climatic conditions, landfill structure, and environmental factors. Then, we classified the existing methods for predicting leachate production into four categories: water balance formula, water balance model, empirical formula, and artificial intelligence model methods. Advantages, disadvantages, and applicability of different leachate production prediction methods are compared and analysed. Furthermore, limitations in the existing leachate production prediction methods for MSW landfills and scope for future research are discussed.

Overexpression of FHL1 suppresses papillary thyroid cancer proliferation and progression via inhibiting Wnt/ß-catenin pathway.

PURPOSE: The four and a half LIM domain protein 1 (FHL1) has been found to act as a tumor suppressor in several cancers. However, the clinical and functional significance, as well as underlying molecular mechanisms of FHL1 in papillary thyroid cancer (PTC) are largely unknown. METHODS: Bioinformatics analyses, qRT-PCR and Western blotting were used to investigate the expression of FHL1 in PTC. Cell proliferation was measured using CCK8, Edu, colony formation, and flow cytometry assays. Cell migration and invasion were examined by wound healing and Transwell assays. qRT-PCR, Western blot, immunofluorescence and Top/Fop reporter assays were performed to assess the underlying mechanisms. RESULTS: FHL1 expression was significantly downregulated in PTC. FHL1 downregulation negatively correlated with stage, T classification, and N classification of the patients. The downregulation of FHL1 is associated with poor prognosis. Overexpression of FHL1 inhibited PTC cells' proliferation, invasion, migration and Wnt/ß-catenin pathway activity. LiCl partially restored the inhibitory effects of FHL1 on aggressive phenotypes and Wnt/ß-catenin pathway activity of PTC cells. CONCLUSION: FHL1 is downregulated in PTC and its expression is associated with better clinical outcomes for patients with the disease. FHL1 acts as a tumor suppressor via, at least partially, suppressing Wnt/ß-catenin pathway.

FLNA overexpression promotes papillary thyroid cancer aggression via the FAK/AKT signaling pathway.

Background: Filamin A (FLNA) is a member of the filamin family and has been found to be critical for the progression of several cancers. However, its biological function in papillary thyroid cancer (PTC) remains largely unexplored. Methods: Data from The Cancer Genome Atlas (TCGA) databases were utilized to analyze the FLNA expression level and its influence on the clinical implications of patients with PTC. Gene Expression Omnibus (GEO) and qRT-PCR was used to verify the expression levels of FLNA in PTC. Kaplan-Meier survival analysis was conducted to evaluate the prognostic value of FLNA in PTC. Transwell assays and wound healing were performed to examine the biological function of FLNA knockdown in PTC cells. Gene set enrichment analysis (GSEA) and Western blotting were conducted to investigate the potential mechanisms underlying the role of FLNA in PTC progression. In addition, the relationship between FLNA expression and the tumor immune microenvironment (TME) in PTC was explored. Results: FLNA was significantly upregulated in PTC tissues. High expression levels of FLNA was correlated with advanced TNM stage, T stage, and N stage, as well as poor disease-free interval (DFI) and progression-free interval (PFI) time in PTC patients. Moreover, we found that FLNA knockdown inhibited the migration and invasion of PTC cells. Mechanistically, FLNA knockdown inhibited epithelial-mesenchymal transition (EMT) in PTC and affected the activation of the FAK/AKT signaling pathway. In addition, FLNA expression was associated with TME in PTC. Conclusion: FLNA may be regarded as a new therapeutic target for PTC patients.

Evaluation of the learning state of online video courses based on functional near infrared spectroscopy.

Studying brain activity during online learning will help to improve research on brain function based on real online learning situations, and will also promote the scientific evaluation of online education. Existing research focuses on enhancing learning effects and evaluating the learning process associated with online learning from an attentional perspective. We aimed to comparatively analyze the differences in prefrontal cortex (PFC) activity during resting, studying, and question-answering states in online learning and to establish a classification model of the learning state that would be useful for the evaluation of online learning. Nineteen university students performed experiments using functional near-infrared spectroscopy (fNIRS) to monitor the prefrontal lobes. The resting time at the start of the experiment was the resting state, watching 13 videos was the learning state, and answering questions after the video was the answering state. Differences in student activity between these three states were analyzed using a general linear model, 1s fNIRS data clips, and features, including averages from the three states, were classified using machine learning classification models such as support vector machines and k-nearest neighbor. The results show that the resting state is more active than learning in the dorsolateral prefrontal cortex, while answering questions is the most active of the three states in the entire PFC, and k-nearest neighbor achieves 98.5% classification accuracy for 1s fNIRS data. The results clarify the differences in PFC activity between resting, learning, and question-answering states in online learning scenarios and support the feasibility of developing an online learning assessment system using fNIRS and machine learning techniques.

ATP production rate via creatine kinase or ATP synthase in vivo: a novel superfast magnetization saturation transfer method.

RATIONALE: ³¹P magnetization saturation transfer (MST) experiment is the most widely used method to study ATP metabolism kinetics. However, its lengthy data acquisition time greatly limits the wide biomedical applications in vivo, especially for studies requiring high spatial and temporal resolutions. OBJECTIVE: We aimed to develop a novel superfast MST method that can accurately quantify ATP production rate constants (k(f)) through creatine kinase (CK) or ATP synthase (ATPase) with 2 spectra. METHODS AND RESULTS: The T1(nom) (T1 nominal) method uses a correction factor to compensate the partially relaxed MST experiments, thus allowing measurement of enzyme kinetics with an arbitrary repetition time and flip angle, which consequently reduces the data acquisition time of a transmurally differentiated CK k(f) measurement by 91% as compared with the conventional method with spatial localization. The novel T1(nom) method is validated theoretically with numeric simulation, and further verified with in vivo swine hearts, as well as CK and ATPase activities in rat brain at 9.4 Tesla. Importantly, the in vivo data from swine hearts demonstrate, for the first time, that within an observation window of 30 minutes, the inhibition of CK activity by iodoacetamide does not limit left ventricular chamber contractile function. CONCLUSIONS: A novel MST method for superfast examination of enzyme kinetics in vivo has been developed and verified theoretically and experimentally. In the in vivo normal heart, redundant multiple supporting systems of myocardial ATP production, transportation, and utilization exist, such that inhibition of one mechanism does not impair the normal left ventricular contractile performance.

Analysis of the existence form of landfill leachate water level and its development pattern under the condition of considering internal source water: a case study.

In this paper, we study the existence form and development pattern of leachate level in the pile through a case of high water level landfill. The innovation of this paper is to consider not only the infiltration of rainfall, but also the internal source water of waste as the source of leachate. There is one main water level and multiple layers of stagnant water levels in this study area. The main water level of the pile first appears along the base slope of the landfill, and the trend of development is to connect from the bottom pile upwards layer by layer. The connection point of each layer gradually moves from the upstream side to the downstream side with time, and the main water level is formed by the gradual connection of the stagnant water level in each layer of the pile. Piles filled with slope as the base surface, and the stagnant water level in the pile first develops on the slope. And piles that are filled with a gentle base surface, and stagnant water level in the pile is uniformly developed on the base surface. At least one layer of stagnant water level exists in each layer of the pile, and multiple saturated zones occur in landfills with gentle base surfaces, and the saturation zone of the upper and lower waste pile will be penetrated. Depending on the form of leachate water level present in the pile, the location can be reasonably chosen for engineered precipitation of the landfill, and based on the development trend of each water level in the pile, it can provide a reference for the site selection and design of the landfill.