Prediction model of water content in surface dead fuel based on convolution neural network and meteoro-logical factors regression.

Water content of surface fuels is an important indicator of forest fire risk level and fire behavior, and the prediction model of which has a significant effect on fire risk prediction and management. Based on field meteorological factors of Quercus mongolica and Pinus sylvestris var. mongolica forests and water content data of dead fuels on the ground, we conducted the relative importance ranking of meteorological factors random forest and Pearson correlation analysis, and predicted water content of fuels using deeply learned convolutional neural network and meteorological factors regression. The results showed that water content of Q. mongolica fuels in the wild was significantly higher than that of P. sylvestris var. mongolica. The results of random forest showed that the factors that had significant effect on water content of fuel were humidity, temperature, rainfall, wind speed, and solar radiation, with the importance ranking from the largest to the smallest. Results of correlation analysis showed that temperature, humidity, and rainfall of current day had a significant impact on water content of fuels, and certain correlations were observed between meteorological factors. The prediction R2 of the convolutional neural network model for the surface fuel water content of Q. mongolica and P. sylvestris var. mongolica forest was 0.928 and 0.905, the mean absolute error (MAE) was 6.1% and 8.1%, and the mean relative error (MRE) was 8.9% and 4.2%, respectively. However, the R2, MAE, MRE of meteorological factors regression were 0.495 and 0.525, 30.5% and 39.5%, 52.1% and 32.6%, respectively. The precision of convolution neural network model was significantly higher than that of meteorological factors regression. Our results showed that the deeply learned convolutional neural network could provide some reference for the prediction of fuel water content in the future, and effectively support higher level forest fire management.

Prediction models of fire spread rate of Pinus koraiensis plantation's surface fuel.

Pinus koraiensis plantation has high fire risks due to high oil content in branches and leaves. The spread of surface fire is the main way of forest fire expansion. Understanding the surface fire spread rate can provide scientific guidance for fire fighting. We carried out a laboratory experiment with surface fuel of Pinus koraiensis plantation in Maoershan area of Heilongjiang Province. We set different levels of fuel moisture contents (5%, 15%, 25%), fuel loads (0.5, 0.7, 0.9, 1.1 kg·m-2), and slope (0°, 10°, 20°, 30°, 40°) to simulate the characteristics of fuel bed in the field, and quantified the spread rate by thermocouple method. We further compared and analyzed the prediction accuracy of Rothermel model, modified Rothermel model and random forest model, and evaluated the optimal model for predicting the surface fire spread rate of P. koraiensis plantation. The results showed that the overall efficacy of directly using the Rothermel model to predict the surface fire spread rate of P. koraiensis plantations was good, but the prediction result of the spread rate under the conditions of high slope and high moisture content was not satisfied. The Rothermel model after refitting the slope parameters and the random forest model had good prediction efficacy and similar prediction accuracy. The random forest model needed to be further evaluated and verified due to its own characteristics. The modified Rothermel model was more suitable for predicting the surface fire spread rate of P. koraiensis plantations at a slope range of 0°-40° than the others.

Multi-omics analyses of airway host-microbe interactions in chronic obstructive pulmonary disease identify potential therapeutic interventions.

The mechanistic role of the airway microbiome in chronic obstructive pulmonary disease (COPD) remains largely unexplored. We present a landscape of airway microbe-host interactions in COPD through an in-depth profiling of the sputum metagenome, metabolome, host transcriptome and proteome from 99 patients with COPD and 36 healthy individuals in China. Multi-omics data were integrated using sequential mediation analysis, to assess in silico associations of the microbiome with two primary COPD inflammatory endotypes, neutrophilic or eosinophilic inflammation, mediated through microbial metabolic interaction with host gene expression. Hypotheses of microbiome-metabolite-host interaction were identified by leveraging microbial genetic information and established metabolite-human gene pairs. A prominent hypothesis for neutrophil-predominant COPD was altered tryptophan metabolism in airway lactobacilli associated with reduced indole-3-acetic acid (IAA), which was in turn linked to perturbed host interleukin-22 signalling and epithelial cell apoptosis pathways. In vivo and in vitro studies showed that airway microbiome-derived IAA mitigates neutrophilic inflammation, apoptosis, emphysema and lung function decline, via macrophage-epithelial cell cross-talk mediated by interleukin-22. Intranasal inoculation of two airway lactobacilli restored IAA and recapitulated its protective effects in mice. These findings provide the rationale for therapeutically targeting microbe-host interaction in COPD.

Analysis of Multi-Tendon Friction-Based Composite Anchorage Device for CFRP Cables and Its Anchorage Mechanism.

Carbon fiber-reinforced polymer (CFRP) cables are anticipated to be employed in larger, longer, and more durable structures in the engineering field. However, its anchorage devices and mechanism should be appropriately developed and improved. At present, mainly relying on the adhesive force, most anchorage devices may lose their efficiency because of adhesive aging and failure or the slip of an individual tendon. A friction-based composite anchorage device with an integrated bearing of inner cone filler (i.e., load transfer media (LTM)) bonding and a single extruding anchor is proposed, and the anchorage mechanism is examined for Φ7 CFRP cables of strength 2400 MPa. Firstly, sufficient conditions for anti-slip failure of CFRP tendons in the anchorage zone are derived by assuming uniform LTM bonding. The obtained results reveal that the smaller inner pore size of the barrel leads to higher efficiency. Additionally, the maximum efficiency depends on the friction coefficient of the contact surface, the inner cone angle of the barrel, and the diameter and quantity of the CFRP tendons. The necessary conditions for the safety of the CFRP tendon anchorage zone are carefully obtained based on the Tsai-Wu failure criterion. It is concluded that the compressive stress of CFRP tendons in the anchorage zone should gradually increase from the load-bearing end to the no-loading end. Additionally, the relations among the anchorage efficiency coefficient and the CFRP tendon diameter d, the anchorage length l, the dip angle of LTM external conical surface α, and the friction angle ß are derived based on the equivalent failure principle. The CFRP cables of four specifications (i.e., with Φ12, Φ19, Φ37, and Φ121 tendons) are designed under theoretical guidance, and eight static tests are carried out for more verification studies. The test results indicate that the anchorage efficiency coefficient of designed anchorage devices can be over 90%, and even up to 96.8%. Further, the failure modes are divergent destruction, which verifies the reliability of friction-based anchorage devices and provides a solid theoretical foundation for the design and engineering applications of CFRP cables.

[Pyrolysis and gas emissions characteristics of six tree species in Heilongjiang Province, China]. / 黑龙江省6种乔木叶片热解特性及气体释放特征.

Forest fuels are the basis of fire occurrences, while ground dead fuels are an important part of forest fuels. Undestanding the pyrolysis characteristics and gas emissions of forest fuels is of great significance to explore the effects of forest fire on atmospheric environment and carbon balance, as well as to prevent and combat forest fire. In this study, the thermogravimetric analysis and gas emission analysis were conducted on leaf litter of six tree species (Pinus sylvestris var. mongolica, Picea koraiensis, Fraxinus mandshurica, Juglans mandshurica, Quercus mongolica, Betula platyphylla) in Heilongjiang Province to explore the pyrolysis process and combustibility of forest fuels, to analyze their pyrolysis characteristics, pyrolysis kinetics characteristics, gas emission characteristics. A four-dimensional evaluation of their combustibility was conducted based on pyrolysis parameters. The results showed that the pyrolysis temperature of holocellulose in the leaves of those six tree species ranged in 143.31-180.48 ℃ at the beginning and 345.04-394.38 ℃ at the end, lignin pyrolysis temperature ranged in 345.04-394.38 ℃ at the beginning and 582.85-609.31 ℃ at the end. The pyrolysis of the six kinds of arbor blades during the pyrolysis process affected fuel ash content, quality and temperature of the total pyrolysis. The activation energies of two main pyrolysis stages of leaves of six tree species were 18.88-27.08 kJ·mol-1 and 13.25-27.54 kJ·mol-1, respectively, and the pre-exponential factors were 3.13-26.28 min-1 and 1.30-22.55 min-1. The holocellulose activation energy and pre-exponential factor of the pyrolysis stage for P. koraiensis, F. mandshurica, Q. mongolica, and B. platyphylla were greater than that of the lignin pyrolysis stage, while the opposite was true for P. sylvestris var. mongolica and J. mandshurica. The release amounts of CO and CO2 at the pyrolysis stage of the holocellulose was 535.16-880.11 mg·m-3 and 7004.97-10302.05 mg·m-3, and that at the pyrolysis stage of lignin was 240.31-1104.67 mg·m-3 and 20425.60-33946.68 mg·m-3, respectively. The release of CO and CO2 at the pyrolysis stage of healdellulose was less, but mass loss was greater than that at the pyrolysis stage of lignin. In the four-dimensional combustibility ranking of the six tree species leaves, B. platyphylla was the best ignitable, P. koraiensis was the most combustible, and P. sylvestris var. mongolica was the most sustainable and consumable. The ignitability was significantly positively correlated with pyrolysis kinetics parameters of the holocellulose, while the sustainability was negatively correlated with that of lignin.

Choice of operative method for pancreaticojejunostomy and a multivariable study of pancreatic leakage in pancreaticoduodenectomy.

BACKGROUND: As one of the major abdominal operations, pancreaticoduodenectomy (PD) involves many organs. The operation is complex, and the scope of the operation is large, which can cause significant trauma in patients. The operation has a high rate of complications. Pancreatic leakage is the main complication after PD. When pancreatic leakage occurs after PD, it can often lead to abdominal bleeding and infection, threatening the lives of patients. One study found that pancreatic leakage was affected by many factors including the choice of pancreaticojejunostomy method which can be well controlled. AIM: To investigate the choice of operative methods for pancreaticojejunostomy and to conduct a multivariate study of pancreatic leakage in PD. METHODS: A total of 420 patients undergoing PD in our hospital from January 2014 to March 2019 were enrolled and divided into group A (n = 198) and group B (n = 222) according to the pancreatointestinal anastomosis method adopted during the operation. Duct-to-mucosa pancreatojejunostomy was performed in group A and bundled pancreaticojejunostomy was performed in group B. The operation time, intraoperative blood loss, and pancreatic leakage of the two groups were assessed. The occurrence of pancreatic leakage after the operation in different patients was analyzed. RESULTS: The differences in operative time and intraoperative bleeding between groups A and B were not significant (P > 0.05). In group A, the time of pancreatojejunostomy was 26.03 ± 4.40 min and pancreatic duct diameter was 3.90 ± 1.10 mm. These measurements were significantly higher than those in group B (P < 0.05). The differences in the occurrence of pancreatic leakage, abdominal infection, abdominal hemorrhage and gastric retention between group A and group B were not significant (P > 0.05). The rates of pancreatic leakage in patients with preoperative albumin < 30 g/L, preoperative jaundice time ≥ 8 wk, and pancreatic duct diameter < 3 mm, were 23.33%, 33.96%, and 19.01%, respectively. These were significantly higher than those in patients with preoperative albumin ≥ 30 g/L, preoperative jaundice time < 8 wk, and pancreatic duct diameter ≥ 3 cm (P < 0.05). Logistic regression analysis showed that preoperative albumin < 30 g/L, preoperative jaundice time ≥ 8 wk, and pancreatic duct diameter < 3 mm were risk factors for pancreatic leakage after PD (odds ratio = 2.038, 2.416 and 2.670, P < 0.05). CONCLUSION: The pancreatointestinal anastomosis method during PD has no significant effect on the occurrence of pancreatic leakage. The main risk factors for pancreatic leakage include preoperative albumin, preoperative jaundice time, and pancreatic duct diameter.

Evaluation of Antibacterial Effects of Matrix-Induced Silver Ions against Antibiotic-Resistant ESKAPE Pathogens.

Recently, drug-resistant bacterial infections, especially ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.), have become a critical health issue worldwide, highlighting the emerging need for novel antibacterial agents. In this study, silver nanoparticles were extracted from silver-containing mesoporous bioactive glass (MBG-Ag) using four different matrixes, including water, phosphate buffer saline (PBS), tryptic soy broth (TSB), and taurine (Tau). The inductively coupled plasma-mass spectrometer (ICP-MS) results demonstrated that the silver concentration of Tau-Ag was the highest among the four matrixes. The Tau-Ag was also observed to have 87.35% silver ions in its X-ray photoelectron spectrometer (XPS) spectra. The micrograph of transmission electron microscope (TEM) displayed a uniform distribution of silver nanoparticles, which was confined in a smaller size compared to that in TSB-Ag. Moreover, the peak shifts observed in the Fourier-transform infrared spectrometer (FTIR) spectrum implied that the -SO32- and -NH groups in taurine may interact with silver. A low cytotoxicity was noted for Tau-Ag, with approximately 70% of cells surviving at 0.63 mg/mL. Compared to the other three matrix-induced silver agents, Tau-Ag represented a better antibacterial effect against methicillin-resistant Staphylococcus aureus, with a minimum inhibitory concentration (MIC) value of 0.63 mg/mL and a postponed growth of 0.31 mg/mL observed. Further antibacterial examinations illustrated the presence of remarkable antibacterial activities against vancomycin-resistant Enterococcus feacium, carbapenem-resistant Klebsiella pneumoniae, carbapenem-resistant Acinetobacter baumannii, and carbapenem-resistant Pseudomonas aeruginosa. Given our observations and multiple bioactive functions of taurine (prevent patients from inflammation and oxidative-stress injuries), we anticipate that taurine matrix-induced silver ions would be a biomedical material with a high potential for combatting drug-resistant ESKAPE pathogens.

Positive and neutral updating reconsolidate aversive episodic memories via different routes.

Aversive memories are long-lasting and prone to burden our emotional wellbeing and mental health. Yet, how to remedy the maladaptive effects of aversive memories remains elusive. Using memory reactivation and emotional updating manipulations, we investigated how positive and neutral emotion may update aversive memories for reconsolidation in humans. We found that positive updating after reactivation was equivalent to neutral updating in impairing true memories of a previous aversive event after a 12-hour wakeful delay, but induced more false memory. Moreover, additional 12-hour delay with overnight sleep did not further enlarge true memory differences, but attenuated the effect of reactivation and updating on false memory. Interestingly, the neutral rather than the positive updating reduced the emotional arousal of the aversive memory 24 h later. Our findings could serve as a reference for real-world therapeutic applications regarding how positive and neutral updating may reshape aversive memories, especially when taking wake- and sleep-filled reconsolidation into account.

Expression of caspase-3 and hypoxia inducible factor 1α in hepatocellular carcinoma complicated by hemorrhage and necrosis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a malignant tumor that occurs in the liver. Its onset is latent, and it shows high heterogeneity and can readily experience intrahepatic metastasis or systemic metastasis, which seriously affects patients' quality of life. Numerous studies have shown that hypoxia inducible factor1α (HIF-1α) plays a significant role in the occurrence and development of tumors, as it promotes the formation of intratumoral vessels and plays a key role in their metastasis and invasion. Some studies have reported that caspase-3, which is induced by various factors, is involved in the apoptosis of tumor cells. AIM: To investigate the expression of caspase-3 and HIF-1α and their relationship to the prognosis of patients with primary HCC complicated by pathological changes of hemorrhage and necrosis. METHODS: A total of 88 patients with HCC complicated by pathological changes of hemorrhage and necrosis who were treated at our hospital from January 2017 to December 2019 were selected. The expression of caspase-3 and HIF-1α in HCC and paracancerous tissues from these patients was assessed. RESULTS: The positive expression rate of caspase-3 in HCC tissues was 27.27%, which was significantly lower than that in the paracancerous tissues (P < 0.05), while the positive expression rate of HIF-1α was 72.73%, which was significantly higher than that in the paracancerous tissues (P < 0.05). The positive expression rates for caspase-3 in tumor node metastasis (TNM) stage III and lymph node metastasis tissues were 2.78% and 2.50%, respectively, which were significantly lower than those in TNM stage I-II and non-lymph node metastasis tissues (P < 0.05). The positive expression rates of HIF-1α in TNM stage III, lymph node metastasis, and portal vein tumor thrombus tissues were 86.11%, 87.50%, and 88.00%, respectively, and these values were significantly higher than those in TNM stage I-II, non-lymph node metastasis, and portal vein tumor thrombus tissues (P < 0.05). The expression of caspase-3 and HIF-1α in HCC tissues were negatively correlated (r s = - 0.426, P < 0.05). The median overall survival time of HCC patients was 18.90 mo (95% CI: 17.20-19.91). The results of the Cox proportional risk regression model analysis showed that TNM stage, portal vein tumor thrombus, lymph node metastasis, caspase-3 expression, and HIF-1α expression were the factors influencing patient prognosis (P < 0.05). CONCLUSION: The expression of caspase-3 decreases and HIF-1α increases in HCC tissues complicated by pathological changes of hemorrhage and necrosis, and these are related to clinicopathological features and prognosis.

A Refined View of Airway Microbiome in Chronic Obstructive Pulmonary Disease at Species and Strain-Levels.

Little is known about the underlying airway microbiome diversity in chronic obstructive pulmonary disease (COPD) at in-depth taxonomic levels. Here we present the first insights on the COPD airway microbiome at species and strain-levels. The full-length 16S rRNA gene was characterized from sputum in 98 COPD patients and 27 age-matched healthy controls, using the Pacific Biosciences sequencing platform. Individual species within the same genus exhibited reciprocal relationships with COPD and disease severity. Species dominant in health can be taken over by another species within the same genus but with potentially increasing pathogenicity in severe COPD patients. Ralstonia mannitolilytica, an opportunistic pathogen, was significantly increased in frequent exacerbators (fold-change = 4.94, FDR P = 0.005). There were distinct patterns of interaction between bacterial species and host inflammatory mediators according to neutrophilic or eosinophilic inflammations, two major airway inflammatory phenotypes in COPD. Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Neisseria meningitidis were associated with enhanced Th1, Th17 and pro-inflammatory mediators, while a group of seven species including Tropheryma whipplei were specifically associated with Th2 mediators related to eosinophilia. We developed an automated pipeline to assign strain-level taxonomy leveraging bacterial intra-genomic 16S allele frequency. Using this pipeline we further resolved three non-typeable H. influenzae strains PittEE, PittGG and 86-028NP with reasonable precision and uncovered strain-level variation related to airway inflammation. In particular, 86-028NP and PittGG strains exhibited inverse associations with Th2 chemokines CCL17 and CCL13, suggesting their abundances may inversely predict eosinophilic inflammation. A systematic comparison of 16S hypervariable regions indicated V1V3 instead of the commonly used V4 region was the best surrogate for airway microbiome. The full-length 16S data augmented the power of functional inference, which slightly better recapitulated the actual metagenomes. This led to the unique identification of butyrate-producing and nitrate reduction pathways as depleted in COPD. Our analysis uncovered finer-scale airway microbial diversity that was previously underappreciated, thus enabled a refined view of the airway microbiome in COPD.

Multi-omic meta-analysis identifies functional signatures of airway microbiome in chronic obstructive pulmonary disease.

The interaction between airway microbiome and host in chronic obstructive pulmonary disease (COPD) is poorly understood. Here we used a multi-omic meta-analysis approach to characterize the functional signature of airway microbiome in COPD. We retrieved all public COPD sputum microbiome datasets, totaling 1640 samples from 16S rRNA gene datasets and 26 samples from metagenomic datasets from across the world. We identified microbial taxonomic shifts using random effect meta-analysis and established a global classifier for COPD using 12 microbial genera. We inferred the metabolic potentials for the airway microbiome, established their molecular links to host targets, and explored their effects in a separate meta-analysis on 1340 public human airway transcriptome samples for COPD. 29.6% of differentially expressed human pathways were predicted to be targeted by microbiome metabolism. For inferred metabolite-host interactions, the flux of disease-modifying metabolites as predicted from host transcriptome was generally concordant with their predicted metabolic turnover in microbiome, suggesting a synergistic response between microbiome and host in COPD. The meta-analysis results were further validated by a pilot multi-omic study on 18 COPD patients and 10 controls, in which airway metagenome, metabolome, and host transcriptome were simultaneously characterized. 69.9% of the proposed "microbiome-metabolite-host" interaction links were validated in the independent multi-omic data. Butyrate, homocysteine, and palmitate were the microbial metabolites showing strongest interactions with COPD-associated host genes. Our meta-analysis uncovered functional properties of airway microbiome that interacted with COPD host gene signatures, and demonstrated the possibility of leveraging public multi-omic data to interrogate disease biology.