Influence of water coupling coefficient on the blasting effect of red sandstone specimens

This study investigates the impact of different water coupling coefficients on the blasting effect of red sandstone.The analysis is based on the theories of detonation wave and elastic wave,focusing on the variation in wall pressure of the blasting holes.Using DDNP explosive as the explosive load,blasting tests were conducted on red sandstone specimens with four different water coupling coefficients:1.20,1.33,1.50,and 2.00.The study examines the morphologies of the rock specimens after blasting under these different water coupling coefficients.Additionally,the fractal dimensions of the surface cracks resulting from the blasting were calculated to provide a quantitative evaluation of the extent of rock damage.CT scanning and 3D reconstruction were performed on the post-blasting specimens to visually depict the extent of damage and fractures within the rock.Additionally,the volume fractal dimension and damage degree of the post-blasting specimens are calculated.The findings are then combined with numerical simulation to facilitate auxiliary analysis.The results demonstrate that an increase in the water coupling coefficient leads to a reduction in the peak pressure on the hole wall and the crushing zone,enabling more of the explosion energy to be utilized for crack propagation following the explosion.The specimens exhibited distinct failure patterns,resulting in corresponding changes in fractal dimensions.The simulated pore wall pressure–time curve validated the derived theoretical results,whereas the stress cloud map and explosion energy-time curve demonstrated the buffering effect of the water medium.As the water coupling coefficient increases,the buffering effect of the water medium becomes increasingly prominent.

Theoretical and numerical simulation investigation of deep hole dispersed charge cut blasting

Drilling and blasting methods have been used as a common driving technique for shallow-hole driving and blasting in rock roadways.With the advent of digital electronic detonators and the need for increased production efciency,the traditional blasting design is no longer suitable for deep hole blasting.In this paper,a disperse charge cut blasting method was proposed to address the issues of low excavation depth and high block rate in deep hole undercut blasting.First,a blasting model was used to illustrate the mechanism of the deep hole dispersive charge cut blasting process.Then,continuous charge and dispersed charge blasting models were developed using the smooth particle hydrodynamics-fnite element method(SPHFEM).The cutting parameters were determined theoretically,and the cutting efciency was introduced to evaluate the cutting efect.The blasting efects of the two charging models were analyzed utilizing the evolution law of rock damage,the number of rock particles thrown,and the cutting efciency.The results show that using a dispersed charge improves the cutting efciency by about 20%and the rock breakage for the deep hole cut blasting compared to the traditional continuous charge.In addition,important parameters such as cutting hole spacing,cutting hole depth and upper charge proportion also have a signifcant impact on the cutting efect.Finally,the deep hole dispersed charge cut blasting technology is combined with the digital electronic detonator through the feld engineering practice.It provides a reference for the subsequent deep hole cutting blasting and the use of electronic detonators in rock roadways.

Effectiveness of Participatory Teaching Methods in the Standardized Training of Respiratory Medicine Residents

Objective:To explore and analyze the application effect of participatory teaching method in the standardized training of respiratory medicine residents.Methods:The study period was from May 2022 to May 2023.20 doctors in the standardized training of respiratory medicine residency in our hospital were taken as research subjects and grouped into the participatory group(n=10)and the routine group(n=10)by using the random number lottery method.The participatory group practised participatory teaching methods,and the routine group practised routine teaching methods.The results of discharge assessment,teaching evaluation,and mini-Clinical Evaluation Exercise(mini-CEX)assessment were compared between the groups.Results:The theoretical assessment,operational assessment,and total scores of the participatory group were significantly higher than those of the routine group,and the difference was statistically significant(P<0.05).The teaching evaluation of independent learning,theoretical mastery,teamwork,clinical thinking,communication,and learning interest of the participatory group was significantly higher than that of the routine group,and the difference was statistically significant(P<0.05).The mini-CEX assessments of history inquiry,organizational effectiveness,professionalism,physical examination,clinical diagnosis,communication skills,and overall clinical competence of the participatory group were significantly better than those of the routine group,and the difference was statistically significant(P<0.05).The teaching satisfaction of the participatory group was significantly higher than that of the routine group,the difference was statistically significant(P<0.05).Conclusion:Participatory teaching methods can improve the overall level of doctors in the respiratory medicine residency standardized training,and the teaching satisfaction is improved.

Spatial Downscaling of Remote Sensing Precipitation Data in the Beijing-Tianjin-Hebei Region

Precipitation is an important part of the global hydrological cycle. The large- scale, high-precision continuous precipitation data obtained by satellite remote sensing detection technology has become an important source of spatial precipitation data. However, because the spatial resolution of remote sensing precipitation data is still low, it is difficult to meet the needs of hydrological research, which restricts their application in drought and flood analysis, hydrological simulation, etc. In response to this problem, this paper takes the Beijing-Tianjin-Hebei region as the research area, downscaling the TRMM data and the GPM data space of the continuation plan, and increasing the spatial resolution of the data to 1 km. Compared with the original data, spatial downscaling data not only greatly improves the spatial resolution, but also increases the accuracy of the data, which has better applicability.

Fracture characteristics of iron ore under uncoupled blast loading

A blasting experiment was conducted on iron ore samples by considering multiple coupling charge coefficients.The resulting internal fracture and damage characteristics were quantitatively analyzed via computerized tomography(CT),scanning,and three-dimensional(3D)model reconstruction.The results show that the iron ore primarily displayed radial and circumferential cracks along the blast hole under an explosive load.When the decoupling coefficient was small,the crack surface was dominated by transgranular fractures in the form of intracrystalline fractures.As the uncoupling coefficient increased,the crack surface exhibited transgranular and intergranular coupled fracture modes.Using fractal theory to analyze crack distribution characteristics,as the decoupled coefficient increased,the body fractal dimension tended to decrease,and the degree of damage gradually decreased.The degree of damage reached a turning point when the decoupling charge coefficient was approximately 1.33.A numerical simulation suggested that the explosion energy transmitted to the iron ore and the effective stress decrease sharply when the decoupling coefficient exceeds 1.33.In some optimal uncoupling coefficient range,excessive fragmentation of the ore body is prevented,thereby allowing full use of the explosive energy.

Effect of sodium content on the interaction between Ni and support and catalytic performance for syngas methanation over Ni/Zr–Yb–O catalysts

In this paper, Ni/Zr–Yb–O catalysts with different sodium contents are prepared by a co-precipitation method, using aqueous Na2CO3 solution as a precipitant, and the effect of sodium on the catalyst structure and catalytic performance for syngas methanation is extensively investigated using five Ni/Zr–Yb–O catalysts, containing 0, 0.5, 1.5,4.5 and 13.5 wt% Na^+, those are denoted as Cat-1, Cat-2, Cat-3, Cat-4 and Cat-5 respectively. It is found that the interaction between Ni and support determines the catalytic performance of Ni/Zr–Yb–O and the residual sodium content negatively affects the interaction between Ni and support. Cat-1 exhibits an excellent catalytic performance.During a long run time of 380 h, no deactivation is observed and both CO conversion and CH4 selectivity maintain a level above 90%. However, Cat-3 and Cat-5 suffer rapid deactivation under the same reaction condition. The characterization results indicate the strong interaction between Ni and support enables Cat-1 to possess well dispersed Ni species, resistance to sintering and carbon deposition and thus the excellent catalytic performance. However, the presence of sodium ions over Ni/Zr–Yb–O degrades the interaction between Ni and support and the catalytic performance, especially for the stability. The relative weak interaction between Ni and support results in severe sintering of both ZrO2 and Ni under the reaction condition, carbon deposition and the poor catalytic performance.

Apatite and Chitin Amendments Promote Microbial Activity and Augment Metal Removal in Marine Sediments

In situ amendments are a promising approach to enhance removal of metal contaminants from diverse environments including soil, groundwater and sediments. Apatite and chitin were selected and tested for copper, chromium, and zinc metal removal in marine sediment samples. Microbiological, molecular biological and chemical analyses were applied to investigate the role of these amendments in metal immobilization processes. Both apatite and chitin promoted microbial growth. These amendments induced corresponding bacterial groups including sulfide producers, iron reducers, and phosphate solubilizers;all that facilitated heavy metal immobilization and removal from marine sediments. Molecular biological approaches showed chitin greatly induced microbial population shifts in sediments and overlying water: chitin only, or chitin with apatite induced growth of bacterial groups such as Acidobacteria, Betaproteobacteria, Epsilonproteobacteria, Firmicutes, Planctomycetes, Rhodospirillaceae, Spirochaetes, and Verrucomicrobia;whereas these bacteria were not present in the control. Community structures were also altered under treatments with increase of relative abundance of Deltaproteobacteria and decrease of Actinobacteria, Alphaproteobacteria, and Nitrospirae. Many ?of these groups of bacteria have been shown to be involved in metal reduction and immobilization. Chemical analysis ?of pore and overlying water also demonstrated metal immobilization primarily under chitin treatments. X-Ray absorption spectroscopy (XAS) spectra showed more sorbed Zn occurred over time in both apatite and chitin treatments (from 9% - 27%). The amendments improved zinc immobilization in marine sediments that led to significant changes in ??the mineralogy: easily mobile Zn hydroxide phase was converted to an immobile Zn phosphate (hopeite). In-situ amendment of apatite and chitin offers a great bioremediation potential for marine sediments contaminated with heavy metals.

Clinical Study of Recombinant Human Endostatin Combined with Iressa in Targeted Treatment of Patients with Lung Adenocarcinoma with Pleural Metastasis

Objective:To evaluate and comprehensively analyze the clinical efficacy of recombinant human endostatin combined with Iressa targeted therapy in patients with pleural metastasis of lung adenocarcinoma.Methods:The interval of the selected study period span was from January 2017 to April 2021.The sample source of the study was 42 patients with lung adenocarcinoma admitted to hospital.The random number table method was used for study grouping,and they were further divided into study groups(n=21,14 cases with pleural metastasis)and control group(n=21,13 cases with pleural metastasis),all patients received systemic chemotherapy with pemetrexed and cisplatin.Patients with pleural metastases in the control group were injected with 60 mg cisplatin into the thoracic cavity.Patients in the study group were treated with Iressa(gefitinib)targeted therapy if genetic testing showed epidermal growth factor receptor(EGRF)mutations,and patients with pleural metastases were treated with pleural metastasis with Endo(recombinant human endostatin YH-16)to control pleural effusion.Two sets of related indicators were compared and analyzed.Results:Comparing the short-term disease control rate,treatment effectiveness and long-term survival rate between the two groups shows that the study group has more advantages(P<0.05).In the comparison between the two groups of serum markers and related indicators,the study group has more advantages(P<0.05),whereas in the comparison between the two groups in the incidence of adverse reactions,there is no significant difference(P>0.05).Based on statistics of the recurrence rate of pleural fluid in the two groups,the study group is significantly lower than the control group(P<0.05).Conclusion:Recombinant human endostatin combined with Iressa targeted therapy for patients with lung adenocarcinoma with pleural metastasis has significant short-term and long-term effects without serious adverse reactions.It can be fully promoted in medical institutions at all levels.

Clinical Analysis of Early Application of Bi-level Positive Airway Pressure ventilation in the Treatment of COPD with Type II Respiratory Failure

Objective:To analyze the clinical efficacy of early application of bi-level positive airway pressure ventilation in the treatment of COPD with type II respiratory failure.Method:A total of 58 patients with COPD and type II respiratory failure admitted to our hospital from January 2017 to January 2019 were randomly divided into observation group and control group,with 29 cases in each group.Among them,the control group was received routine treatment while the observation group was treated with bi-level positive pressure airway ventilation in addition of conventional treatment.The arterial blood gas analysis,mortality rate and hospitalization time of these two groups before and after treatment were compared.Result:The blood pH,partial pressure of oxygen(PaO2)and arterial oxygen saturation(SaO2)of these two groups were significantly higher after the treatment while PaO2 alone was decreased.The difference was statistically significant(P<0.05).The results of arterial blood gas analysis in the observation group were significantly improved compared with those before treatment.The mortality rate and hospitalization time were significantly less than the control group,and the difference was statistically significant(P<0.05).Conclusion:Early clinical application of bi-level positive airway pressure ventilation in the treatment of COPD with type II respiratory failure has a significant clinical effect in reducing the mortality rate and hospitalization time of patients,and thus it is worthy of clinical application.

Study on the Clinical Efficacy and Safety of Endostar Combined with Pemetrexed and Cisplatin in the Treatment of Lung Adenocarcinoma

Objective:To analyze and study the efficacy and safety of Endu combined with pemetrexed and cisplatin in the clinical treatment of lung adenocarcinoma.Methods:From August 2016 to September 2020,32 patients with lung adenocarcinoma who were treated in our hospital were selected for group trials.According to their specific treatment plan,the patients were divided into control group and experimental group,with 16 cases in each group.The control group was treated with pemetrexed and cisplatin,and the experimental group was treated with Endostar combined with the treatment received by the control group.The clinical efficacy and safety of the two regimens were assessed by comparing the changes in symptoms and the incidence of adverse reactions between the two groups of patients after treatment.Results:The disease control rate of the experimental group was significantly higher than that of the control group,and there was no significant difference in the incidence of adverse reactions between the two groups.Conclusions:From the experimental results,we found that the treatment of patients with lung adenocarcinoma by Endostar combined with pemetrexed and cisplatin can effectively improve the treatment efficacy without increasing adverse reactions and therefore relevant chemotherapy regimens can be considered for wider clinical applications.

Large-Scale CRISPR Screen of LDLR Pathogenic Variants

Familial hypercholesterolemia(FH)is a frequently occurring genetic disorder that is linked to early-onset cardiovascular disease.If left untreated,patients with this condition can develop severe cardiovascular complications.Unfortunately,many patients remain undiagnosed,and even when diagnosed,the treatment is often not optimal.Although mutations in the LDLR gene are the primary cause of FH,predicting whether novel variants are pathogenic is not a straightforward task.Understanding the functionality of LDLR variants is crucial in uncovering the genetic basis of FH.Our study utilized CRISPR/Cas9 cytosine base editors in pooled screens to establish a novel approach for functionally assessing tens of thousands of LDLR variants on a large scale.A total of more than 100 single guide RNAs(sgRNAs)targeting LDLR pathogenic mutations were successfully screened with relatively high accuracy.Out of these,5 sgRNAs were further subjected to functional verification studies,including 1 in the promoter,1 in the antisense RNA,1 in the exon,and 2 in the intron.Except for the variant caused by the sgRNA located at intron 16,the functionalities of the other LDLR variants were all downregulated.The high similarity of LDLR intron sequences may lead to some false positives.Overall,these results confirm the reliability of the large-scale screening strategy for functional analysis of LDLR variants,and the screened candidate pathogenic mutations could be used as an auxiliary means of clinical gene detection to prevent FH-induced heart disease.

The Arabidopsis Anaphase-Promoting Complex/Cyclosome Subunit 1 is Critical for Both Female Gametogenesis and Embryogenesis

Anaphase-promoting complex/cyclosome （APC/C）, a multisubunit E3 ligase, plays a critical role in cell cycle control, but the functional characterization of each subunit has not yet been completed. To investigate the function of APC1 in Arabidopsis, we analyzed four mutant alleles of APC1, and found that mutation in APC1 resulted in significantly reduced plant fertility, accumulation of cyclin B, and disrupted auxin distribution in embryos. The three mutant alleles apcl-1, apcl-2 and apcl-3 shared variable defects in female gametogenesis including degradation, abnormal nuclear number, and disrupted polarity of nuclei in the embryo sac as well as in embryogenesis, in which embryos were arrested at multiple stages. All of these defects are similar to those previously identified in apc4. The mutant apcl-4, in which the T-DNA was inserted after the transmembrane domain at the C-terminus, showed much more severe phenotypes; that is, most of the ovules were arrested at the one-nucleate female gametophyte stage （stage FG1）. In the apcl apc4 double mutants, the fertility was further reduced by one-third in apcl-ll＋ apc4-1/＋, and in some cases no ovules even survived in siliques of apcl-4/＋ apc4-1/＋. Our data thus suggest that APC1, an essential component of APC/C, plays a synergistic role with APC4 both in female gametogenesis and in embryogenesis.

Novel 3D Printed Modular Hemipelvic Prosthesis for Successful Hemipelvic Arthroplasty： A Case Study

In this study, in order to prevent the failure of hemipelvic arthroplasty using a patient-specific Computer-Aided Design （CAD） and Additive Manufacturing （AM） approach, a new design for modular hemipelvic prosthesis was developed. Moreover, the biomechanical properties of the new design were determined. The 3D printed pelvic prosthesis with a sacrum portion that completely matches the back surface of the patient＇s sacrum offers more potential for bone ingrowth between the host bone and prosthesis. The new approach integrated the capabilities of digital medical imaging techniques, CAD and metal AM to realize a modular hemipelvic prosthesis. The patient＇s pelvic Digital Imaging and Communication in Medicine （DICOM） data were imported into Mimics software to construct a digital representative patient model for design of the prosthesis. A physical model was obtained using a Stereolithography （SLA） 3D printer for preoperative planning. The final customized implant was designed by using UG NX 10.0 software. Then a surgically modular hemipelvic prosthesis was fabricated from the Ti6Al4V titanium alloy by electron beam melting technology. The operation was performed according to the preoperative planning. The outcome of the operation was good at the 6-month follow-up. Also, the stress distribution and the relative micromotion revealed positive results based on a finite element model built to detect prosthesis stability. The 3D printed modular hemipelvic prosthesis provided good resolution for the failure of hemipelvic arthroplasty. Personal customization will be important in future surgeries aiming at improving the anatomy and function of the implant.

Seasonal and interannual variations of ecosystem photosynthetic characteristics in a semi-arid grassland of Northern China

The ecosystem apparent quantum yield(α),maximum rate of gross CO_(2) assimilation(Pmax)and daytime ecosystem respiration rate(R.),reflecting the physiological functioning of ecosystem,are vital photosynthetic parameters for the estimation of ecosystem carbon budget.Climatic drivers may affect photosynthetic parameters both directly and indirectly by altering the response of vegetation.However,the relative contribution and regulation pathway of environmental and physiological controls remain unclear,especially in semi-arid grasslands.We analyzed seasonal and interannual variations of photosynthetic parameters derived from eddy-covariance observation in a typical semi-arid grassland in Inner Mongolia,Northern China,over 12 years from 2006 to 2017.Regression analyses and a structural equation model(SEM)were adopted to separate the contributions of environmental and physiological effects.The photosynthetic parameters showed unimodal seasonal patterns and significantly interannual variations.Variations of air temperature(T,)and soil water content(SWC)drove the seasonal patterns of photosynthetic parameters,while SWC predominated their interannual variations.Moreover,contrasting with the predominant roles of T,onαand Ra,SWC explained more variance of Pmax than T,Results of SEM revealed that environmental factors impacted photosynthetic parameters both directly and indirectly through regulating physiological responses reflected by stomatal conductance at the canopy level.Moreover,leaf area index(LAl)directly affectedα,Pmax and R,and dominated the variation of Pmax.On the other hand,SWC influenced photosynthetic parameters indirectly through LAl and canopy surface conductance(gc).Our findings highlight the importance of physiological regulation on the photosynthetic parameters and carbon assimilation capacity,especially in water-limitedgrassland ecosystems.

Instructive cartilage regeneration modalities with advanced therapeutic implantations under abnormal conditions

The development of interdisciplinary biomedical engineering brings significant breakthroughs to the field of cartilage regeneration.However,cartilage defects are considerably more complicated in clinical conditions,especially when injuries occur at specific sites(e.g.,osteochondral tissue,growth plate,and weight-bearing area)or under inflammatory microenvironments(e.g.,osteoarthritis and rheumatoid arthritis).Therapeutic implantations,including advanced scaffolds,developed growth factors,and various cells alone or in combination currently used to treat cartilage lesions,address cartilage regeneration under abnormal conditions.This review summarizes the strategies for cartilage regeneration at particular sites and pathological microenvironment regulation and discusses the challenges and opportunities for clinical transformation.

Death receptor 6 is a novel plasmacytoid dendritic cell-specific receptor and modulates type I interferon production

Dear Editor, Plasmacytoid dendritic cells （pDCs） are the professional type I interferon-producing cells of the immune system, which rapidly produce massive amounts of type I interferons （IFN-I） in response to viruses or other nucleic acids Iigands through selectively expressed toll-like receptor （TLR）-7 and TLR9 （Siegal et al., 1999）. The activation of pDCs not only inhibits virus replication, but also regulates the function of other immune cells and links the innate and adaptive immunity （Liu, 2005）. The local accumulation of pDCs has been reported in both suppressive and overactive immune status （Swiecki and Colonna, 2010）, which highlights the importance of characterizing the molecular mechanisms underlying the functional specialization of pDCs in IFN-I production.