The mechanism of inward and outward expansion of multiscale dynamic permeability of coalbed methane at different temperatures

The multiscale micro-nano pores in coal can result in the ultra-low permeability of coal,which restricts the efficiency of gas extraction.It is difficult for the conventional seepage-enhancement measures to affect the nanoscale pores within the coal matrix.Thermal stimulation can reach deep into the micro-nano pores within coal matrix to improve the permeability.Therefore,it is important to study the diffusivity and permeability of the multiscale micro-nano pores at different temperatures.In this study,the experiments of diffusion-seepage measured by the methods of GRI(Gas Research Institution)and steady-state were conducted using a cylindrical coal at different temperatures and pressures.The experimental results show that the apparent diffusion coefficient of cylindrical coal is not constant but variable dynamically;and the classical diffusion model fails to describe the full-time process of gas flow accurately.On this basis,a model of multiscale dynamic apparent diffusion-seepage that can accurately describe the full-time flow process was proposed.As is observed,the apparent permeability attenuates dynamically with time without stress loading,and the initial apparent permeability and the attenuation coefficient increase monotonically with the rise of temperature.Under the stress constraint,the steady-state permeability increases after a decrease as the temperature rises,displaying a“U-shaped”pattern.Without stress constraint,the increasing temperature causes the exterior multiscale pores to expand outward by different degrees so as to increase permeability,while the interior micro-nano pores show three inward and outward expansion mechanisms.Under stress constraint,at low temperature and high effective stress,the increasing temperature causes pores to expand inward and the permeability decreases accordingly.When temperature continues to increase,coal expands outward because the effective stress is counteracted by the thermal stress,leading to an increase in permeability.This study is of significance for thermal gas extraction engineering.

A rapid and accurate direct measurement method of underground coal seam gas content based on dynamic diffusion theory

Coal seam gas content is frequently measured in quantity during underground coal mining operation and coalbed methane(CBM)exploration as a significant basic parameter.Due to the calculation error of lost gas and residual gas in the direct method,the efficiency and accuracy of the current methods are not inadequate to the large area multi-point measurement of coal seam gas content.This paper firstly deduces a simplified theoretical dynamic model for calculating lost gas based on gas dynamic diffusion theory.Secondly,the effects of various factors on gas dynamic diffusion from coal particle are experimentally studied.And sampling procedure of representative coal particle is improved.Thirdly,a new estimation method of residual gas content based on excess adsorption and competitive adsorption theory is proposed.The results showed that the maximum error of calculating the losing gas content by using the new simplified model is only 4%.Considering the influence of particle size on gas diffusion law,the particle size of the collected coal sample is below 0.25 mm,which improves the measurement speed and reflects the safety representativeness of the sample.The determination time of gas content reduced from 36 to 3 h/piece.Moreover,the absolute error is 0.15–0.50 m^3/t,and the relative error is within 5%.A new engineering method for determining the coal seam gas content is developed according to the above research.

An Adaptive User Service Deployment Strategy for Mobile Edge Computing

Mobile edge computing(MEC) is a cloud server running at the edge of a mobile network, which can effectively reduce network communication delay. However, due to the numerous edge servers and devices in the MEC, there may be multiple servers and devices that can provide services to the same user simultaneously. This paper proposes a userside adaptive user service deployment algorithm ASD(Adaptive Service Deployment) based on reinforcement learning algorithms. Without relying on complex system information, it can master only a few tasks and users. In the case of attributes, perform effective service deployment decisions, analyze and redefine the key parameters of existing algorithms, and dynamically adjust strategies according to task types and available node types to optimize user experience delay. Experiments show that the ASD algorithm can implement user-side decision-making for service deployment. While effectively improving parameter settings in the traditional Multi-Armed Bandit algorithm,it can reduce user-perceived delay and enhance service quality compared with other strategies.

Radiotherapy delays malignant transformation and prolongs survival in patients with IDH-mutant gliomas

Objective:IDH-mutant lower-grade gliomas(LGGs,grade 2 or 3)eventually transform into secondary grade 4 astrocytomas(sAIDHmut/G4).Here,we sought to describe the transformation time,risk factors,and outcomes in malignant transformation of IDHmutant LGGs.Methods:We screened data for 108 patients with sAIDHmut/G4 in the Chinese Glioma Genome Atlas who had initial IDH-mutant LGGs and underwent reoperation during 2005–2021.We evaluated the transformation time from IDH-mutant LGGs to sAIDHmut/G4,and associated risk factors and outcomes.Malignant transformation was defined as pathological confirmation of grade 4 astrocytoma.Results:The median age of the 108 patients with IDH-mutant LGGs was 35 years(range,19–54);the median age at transformation was 40 years(range,25–62);and the median follow-up time for all patients was 146 months(range,121–171).The average transformation time was 58.8 months for all patients with LGGs(range,5.9–208.1);63.5 and 51.9 months for grade 2 and 3 gliomas,respectively;and 58.4 and 78.1 months for IDH-mutant/1p/19q-non-codeleted astrocytomas and IDH-mutant/1p/19q-codeleted oligodendrogliomas,respectively.Univariate and multivariate analysis indicated that radiotherapy[hazard ratio(HR),0.29;95%confidence interval(CI),0.137–0.595;P=0.001]and non-A blood type(HR,0.37;95%CI,0.203–0.680;P=0.001)were protective factors against delayed malignant transformation.Radiotherapy was associated with improved survival after transformation(HR,0.44;95%CI,0.241–0.803;P=0.008),overall survival(HR,0.50;95%CI,0.265–0.972;P=0.041),and progression-free survival(HR,0.25;95%CI,0.133–0.479;P<0.0001)in patients with IDH-mutant gliomas.Conclusions:Radiotherapy is associated with delayed malignant transformation and improved survival in patients with IDHmutant gliomas.

附着生物汞甲基化及其对水环境甲基汞归趋的影响

汞是一种重要的全球性污染物。水环境是汞重要的汇,也是汞甲基化和生物累积最重要的场所。作为最重要的初级生产者之一,附着生物广泛存在于湖泊、湿地、溪流等水环境中。相较于底泥和水柱,附着生物具有增强的汞甲基化潜势,是水环境中甲基汞的重要来源以及汞进入食物链的关键途经。附着生物具有多层次的微生物结构及功能复杂性,不同物种间的相互作用使其内部具有明显的氧化还原梯度,形成有利于汞甲基化的缺氧微环境。一方面,附着生物中的藻类和细菌可从周围水体中富集无机汞,为汞甲基化提供充足的底物。另一方面,附着生物中富含多种藻类、细菌等的代谢分泌物,其官能团(如巯基)可调控无机汞的赋存形态并增强其生物有效性。另外,不同微生物之间的代谢物共享可增强汞甲基化细菌的丰度和代谢活性,从而促进甲基汞的生成。附着生物中汞甲基化机制及生物累积的研究可为深入理解水环境中甲基汞的来源及归趋,准确评估汞污染与环境风险提供科学依据与数据支持。

Electric-Induced Cycloelimination for Simulating Structural Plasticity in Organic Nociceptors

Continuous lifelong acquisition,updating,and finetuning of knowledge and skills is of crucial significance for the survival of humans.However,current neuromorphic devices exhibit obvious catastrophic forgetting when restimulated by new information.This remains a challenge for neuromorphic devices and artificial intelligence to achieve continuous learning.Herein,we propose an electric-induced cycloelimination strategy to realize an organic transistor nociceptor that can simulate synaptic and structural plasticity.The system benefits from the ring-opening characteristics of cross-linked poly(vinyl cinnamate)under a strong pulse voltage,during which new energy-level trap states are formed.The prepared organic transistor nociceptors exhibit both structural and synaptic plasticity.They simulate the characteristics of human nociceptors,including threshold,relaxation,sensitization,and maladaptation behavior.For the first time,we have simulated and explored the structural plasticity behavior in organisms based on electronic devices.More remarkably,the transistor nociceptors realize the reinput of information without forgetting the initial informa tion.The strategy developed for the preparation of organic transistor nociceptors provides insights for addressing the catastrophic forgetting in the lifelong learning of intelligent neuromorphic devices.

Roadside cross-camera vehicle tracking combining visual and spatial-temporal information for a cloud control system

Roadside cameras play a crucial role in road traffic,serving as an indispensable part of integrated vehicleroad-cloud systems due to their extensive visibility and monitoring capabilities.Nevertheless,these cameras face challenges in continuously tracking targets across perception domains.To address the issue of tracking vehicles across nonoverlapping perception domains between cameras,we propose a cross-camera vehicle tracking method within a Vehicle–Road–Cloud system that integrates visual and spatiotemporal information.A Gaussian model with microlevel traffic features is trained using vehicle information obtained through online tracking.Finally,the association of vehicle targets is achieved through the Gaussian model combining time and visual feature information.The experimental results indicate that the proposed system demonstrates excellent performance.

hgcA/B基因介导的汞甲基化分子机制及其应用

作为一种强神经毒性物质,环境中的甲基汞(MeHg)主要由产甲烷菌、硫酸盐还原菌、铁还原菌等厌氧微生物产生,可通过水生食物链积累并作用于人体。汞甲基化基因hgcA/B明确以后,不仅扩大了可探知的汞甲基化微生物范围,也为汞甲基化生物分子机制的探索提供了新的方向。本文1)概述了hgcA/B及其表达产物HgcA、HgcB的预测结构和生物体内的汞甲基化分子机制,2)讨论了基于hgcA/B的环境汞甲基化研究进展,3)总结了现有hgcA/B研究存在的不足,4)对汞甲基化基因领域的研究方向进行了展望。

Characterization of somatic mutations of colorectal tumor in a patient with concurrent APC and MLH1 germline mutations

The two most common inherited forms of colorectal cancer(CRC)are familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer.They are caused by germline mutations in the APC and mismatch repair genes,respectively.1 The simultaneous inheritance of both an APC gene mutation and a mismatch repair gene mutation is very rare.In this study,we reported a coinheritance of mutations in the APC and MLH1 genes in a 20-year-old patient with CRC and multiple polyposes.We described for the first time the somatic mutational profile of a colorectal tumor harboring concurrent germline mutations in the APC and MLH1 genes.

A Wheeled Wall-Climbing Robot with Bio-Inspired Spine Mechanisms

This paper presents a wheeled wall-climbing robot with the ability to climb concrete, brick walls using circular arrays of miniature spines located around the wheel. The robot consists of two driving wheels and a flexible tail, just like letter “T”, so it is called Tbot. The simple and effective structure of Tbot enables it to be steerable and to transition from horizontal to vertical surfaces rapidly and stably. Inspired by the structure and mechanics of the tarsal chain in the Serica orientalis Motschulsky, a compliant spine mechanism was developed. With the bio-inspired compliant spine mechanism, the climbing performance of Tbot was improved. It could climb on 100° （10° past vertical） brick walls at a speed of 10 cm·s^-1. A mechanical model is also presented to analyze the forces acting on spine during a climbing cycle as well as load share between multi-spines. The simu- lation and experiment results show that the mechanical model is suitable and useful in the optimum design of Tbot.

A Track-type Inverted Climbing Robot with Bio-inspired Spiny Grippers

To enable the capacity of climbing robots to work on steep surfaces,especially on inverted surfaces,is a fundamental but challenging task.This capacity can extend the reachable workspace and applications of climbing robots.A track-type inverted climbing robot called SpinyCrawler was developed in this paper.Using a spiny track with an opposed gripping mechanism,the robot was experimentally demonstrated to have the ability of generating considerable adhesion to achieve stable inverted climbing.First,to guarantee reliable attachment of the robot on rough ceilings,a spiny gripper inspired by the opposed gripping prolegs of caterpillars is designed,and a gripping model of the interaction between spines and the ceiling asperities is established and analyzed.Second,a spiny track is developed by assembling dozens of spiny grippers to enable continuous attachment.A cam mechanism is introduced in the robot design without extra actuators to achieve stable attachment and easy detachment during continuous climbing.Finally,climbing experiments are conducted on different surfaces,using a SpinyCrawler prototype.Experimental results demonstrated stable climbing ability on various rough inverted and vertical surfaces,including concrete walls,crushed stone walls,sandpaper walls,brick walls,and brick ceilings.

High-dose radiation associated with improved survival in IDH-wildtype lowgrade glioma

Background:As molecular advances have deepened the knowledge on low-grade glioma(LGG),we investigated the effect of higher radiation dose on the survival of IDH-wildtype(IDHwt)LGG.Methods:In the current study,52 IDHwt LGG patients who received radiotherapy were enrolled from the Chinese Glioma Genome Atlas dataset.Radiation doses>54 Gy were defined as high-dose,whereas doses≤54 Gy were defined as low-dose.We performed univariate and multivariate survival analyses to examine the prognostic role of high-dose radiotherapy.Results:In total,the radiation dose ranged from 48.6 Gy to 61.2 Gy,with a median of 55.8 Gy,and 31 patients were grouped into high-dose radiation.Univariate survival analysis indicated that high-dose radiotherapy(p=0.015),tumors located in the frontal lobe(p=0.009),and pathology of astrocytoma(p=0.037)were significantly prognostic factors for overall survival.In multivariate survival analysis,high-dose radiotherapy(p=0.028)and tumors located in the frontal lobe(p=0.016)were independently associated with better overall survival.Conclusions:In conclusion,high-dose radiotherapy independently improved the survival of IDHwt LGG.This can guide treatments for glioma with known molecular characteristics.

Risk factors and treatments for brain metastasis in patients with adenocarcinoma of the lung: a retrospective analysis of 373 patients

Background: Risk factors and treatments for brain metastasis (BM) in patients with adenocarcinoma have not been fully profiled in previous studies because of the enrolment of patients with tumours of mixed histology. Thus, we specifically addressed the issue in patients with adenocarcinoma. Methods: Clinical data for 373 patients with pathologically confirmed adenocarcinoma were studied retrospectively. Factors including age (≤60 vs.＞60), gender (male vs. female), stage at diagnosis, T status (T1-2 vs. T3-4), N status (N0-1 vs. N2-3), epidermal growth factor receptor (EGFR) mutation status (wild-type vs. mutant) and smoking status (never vs. current) were analyzed. Results: In multivariate analysis, age (P=0.006) and N status (P=0.041) were independent risk factors for BM. In patients with BM, adding systemic therapy to local therapy improved median post-brain-metastasis survival (mPBMS) (P=0.02). However, if stratification was conducted according to the recursive partitioning analysis (RPA) classification or graded prognostic assessment (GPA) scoring, only patients in RPA class Ⅱ (P=0.020) or with GPA score 1.5-2.5 (P=0.032) could benefit from local plus systemic therapy. Those who received both pemetrexed and tyrosine kinase inhibitors (TKIs) as systemic therapies had a longer mPBMS than those who received TKIs alone, regardless of whether local therapy was applied. In patients with EGFR-sensitive mutations, TKIs therapy led to a longer mPBMS than conventional chemotherapy (P=0.002). Conclusions: Adenocarcinoma patients who were younger than 60 years of age and those with N2-3 disease have a significantly higher risk of BM. The addition of systemic therapy to local therapy can significantly prolong mPBMS, but the survival benefit confined in certain populations. Patients with opportunity to receive both pemetrexed and TKIs had the longest mPBMS.

Identifying the viscoelastic properties of soft matter from the indentation response of a hard film-soft substrate system

The indentation technique is widely used in measuring the mechanical properties of soft matter at the microscale or nanoscale,but still faces challenges by these unique properties as well as the consequent strong surface adhesion, including the strong nonlinear effect, unclear judgment of the contact point, difficulties in estimating the contact area, and the risk of the indenter piercing the sample. Here we propose a two-step method to solve these problems: lay a hard film on a soft matter, and obtain the viscoelastic properties of this soft matter through the indentation response of this composite structure. We first establish a theoretical indentation model of the hard film-soft substrate system based on the theory of plates, elastic-viscoelastic correspondence principle and Boltzmann superposition principle. To verify the correctness of this method, we measure the mechanical properties of the methyl vinyl silicone rubber(MVSR) covered by a Cu nanofilm. Finally, we test the effectiveness and error sensitivity of this method with the finite element method(FEM). The results show that our method can accurately measure the mechanical properties of soft matter, while effectively circumventing the problems of the traditional indentation technique.

Risk factors of brain metastasis of lung squamous cell carcinoma:a retrospective analysis of 188 patients from single center

Background:To explore risk factors and the efficacy of treatment strategies for brain metastasis (BM) in squamous cell carcinoma (SCC) of the lung.Methods:The clinical data of 188 pathologically confirmed as squamous cell carcinoma or adenosquamous carcinoma patients were studied retrospectively. Factors including age (<60 vs.≥60), gender, stage at diagnosis, T status (T1-2 vs. T3-4), N status (N0-1 vs. N2-3), histology (squamous vs. adenosquamous), smoking history (non-smoker vs. currentsmoker) and serum tumor markers (normal vs. elevated) were analyzed.Results:The incidence of BM was 19.1％(36/188) in our cohort. Patients who were female (p=0.005), had advanced disease at diagnosis (p<0.001), had adenosquamous carcinoma histology (p=0.033) or had elevated serum level of CEA at diagnosis (p<0.001) had significantly higher incidence of BM. In multivariate analysis, female (p=0.034, HR=18.874) and elevated serum level of CEA at diagnosis (p=0.009, HR=19.824) were independent risk factors of BM. BM patients who received additional systemic therapy after local therapy had significantly longer post-BM survival than those who received local therapy only (p=0.004, HR=0.058). Gemcitabine/platinum-containingregimen (GP) and taxans/platinum-containing regimen (TP) led to comparable brain-metastasis-free survival (BMFS) (p=0.10).Conclusions:Females and patients with elevated serum level of CEA at diagnosis had a higher risk of developing BM. The following systemic therapy after local therapy prolonged the survival of BM patient, but the efficacy of GP and TP was comparable in terms of preventing BM.

Emergency irradiation of 3.4Gy/2f in pineal gland germinoma patients with symptomatic hydrocephalus

Surgical interventions including ventriculostomy and ventriculo-peritoneal shunt were usually administrated in pineal germ cell tumor patients with symptomatic hydrocephalus. Considering higher sensitivity of germinoma to anti-tumor therapy, we explored emergency irradiation as non-invasive measure in this situation. Methods: Data of 35 germinoma patients with symptomatic hydrocephalus who received emergency irradiation of 3. 4 Gy/2f were studied retrospectively. The maximum width of frontal horn and the minimum width of trunk of corpus cal osum (TCC) were measured to evaluate hydrocephalus changing. Besides, mean deviation (MD) of Humphrey perimetry was employed to evaluate visual field defect. Correlations between hydrocephalus changing and clinical factors, including age, percentage of tumor regression, radiographic re-evaluation interval, and serum beta-human chorionic gonadotropin (β-HCG) level, were analyzed. Results: The median maximum diameter and volume of pineal lesions was 27 mm (range 10–55 mm) and 6.5cm3 (range 0.4–74.1 cm3), respectively. At median 8 days after irradiation, the median percentage of tumor remission was 55% (range 10–100%). The median maximum width of FN and the median minimum width of TCC were 11.6 mm and 39.0 mm, and 8.0 mm and 31.4 mm, before and after irradiation, respectively. The improvement of both parameters reached significant level (p < 0.001). However, none clinical factor was found to have correlation with their improvement. In 14 patients with paired data of pre- and post-irradiation MD, its change did not reach the significant level for both eyes. Al patients successful y received subsequent chemoradiotherapy without surgical intervention. Conclusions: Emergency irradiation of 3.4 Gy/2f was an effective non-invasive measure to relief hydrocephalus in pineal germinoma patients.

CACA guidelines for holistic integrative management of glioma

Glioma of the brain is a kind of tumor originating from neuroglial cells.It is the most common primary intracranial tumor,accounting for~30%of all central nervous system tumors and 80% of malignant brain tumors.Glioma is characterized by high disability and recurrence rates.The disease seriously threatens the life of patients,afects their quality of life,and brings a heavy economic and psychological burden to patients,families,and society.With the progression of molecular genetic testing technology and the completion of various clinical trials,the classifcation scheme for glioma is increasingly well established.Diagnosis and treatment regimens,including traditional and new regimens,are becoming increasingly specialized and standardized.The purpose is to develop a clinical diagnosis and treatment guideline for glioma in the Chinese population suitable for Chinese doctors and the general population based on domestic and international glioma research progress.Thus,domestic practitioners in the feld can obtain current information and provide better service to patients with glioma,promoting the development of domestic clinical medicine and basic research on glioma.

HOPF BIFURCATION OF AN INFECTED PREDATOR-PREY SYSTEM WITH PREY REFUGE

In this paper, an infected predator-prey model with prey refuge is investigated. The effects of refuge on the stability of the equilibria of the system are analyzed. Moreover, using the criterion introduced by Liu, we derive the Hopf bifurcation conditions of the system with respect to the refuge value.

Bogdanov-Takens bifurcation with codimension three of a predator-prey system suffering the additive Allee effect

In the present work, research efforts have focused on investigating codimension two and three Bogdanov-Takens bifurcations of a predator-prey system with additive Allee effect. According to the existence conditions of Bogdanov-Takens bifurcation, we give the associated generic unfolding, and derive the dynamical classification in the perturbation parameter plane using some smooth parameter-dependent transformations of coordinate. Moreover, some numerical examples and simulations are performed to complete and illustrate our results.