Theory,technology and application of grouted bolting in soft rock roadways of deep coal mines

The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.

Research Progress on Bolting and Flowering Characteristics of Cruciferous Vegetables

There are many varieties of vegetables in Cruciferae,which have a wide distribution and occupy an important position in the global vegetable industry.The bolting period is a crucial stage in the growth cycle of cruciferous plants,which directly affects the yield and quality of vegetable crops.This paper summarized the research progress on the physiological and biochemical characteristics,molecular genetic mechanisms and molecular markers of the flowering and bolting traits in cruciferous vegetables,in order to provide new ideas for revealing the regulatory mechanisms of flowering and bolting in cruciferous vegetables and to provide reference for the breeding of new varieties of cruciferous vegetables that are resistant to flowering.

Polyneuropathy organomegaly endocrinopathy M-protein and skin changes syndrome with ascites as an early-stage manifestation:A case report

BACKGROUND Polyneuropathy organomegaly endocrinopathy M-protein and skin changes(POEMS)syndrome is a rare paraneoplastic syndrome caused by a potential plasma cell tumor.The clinical manifestations of POEMS syndrome are diverse.Due to the insidious onset and lack of specific early-stage manifestations,POEMS syndrome is easily misdiagnosed or never diagnosed,leading to delayed treatment.Neurological symptoms are usually the first clinical manifestation,while ascites is a rare symptom in patients with POEMS syndrome.CASE SUMMARY A female patient presented with unexplained ascites as an initial symptom,which is a rare early-stage manifestation of the condition.After 1 year,the patient gradually developed progressive renal impairment,anemia,polyserosal effusion,edema,swollen lymph nodes on the neck,armpits,and groin,and decreased muscle strength of the lower extremities.The patient was eventually diagnosed with POEMS syndrome after multidisciplinary team discussion.Treatment comprised bortezomib+dexamethasone,continuous renal replacement therapy,chest and abdominal closed drainage,transfusions of erythrocytes and platelets,and other symptomatic and supportive treatments.The patient’s condition initially improved after treatment.However,then her symptoms worsened,and she succumbed to the illness and died.CONCLUSION Ascites is a potential early manifestation of POEMS syndrome,and this diagnosis should be considered for patients with unexplained ascites.Furthermore,multidisciplinary team discussion is helpful in diagnosing POEMS syndrome.

Provision of Fertility Preservation for Young Women with Early-Stage Breast Cancer

Breast cancer is the most common cancer in women worldwide, constituting 25% of all cancer diagnoses. Even though it is only affecting 4% - 6% of women under the age of 40, it remains the most common malignancy among younger patients. Advancement in the treatment and earlier detection gives excellent 5 years of survival. However, the standard treatment that comprises surgical-chemo radiation therapy or hormonal treatment often results in an increased incidence of treatment-induced infertility. Therefore, adding fertility preservation to primary cancer treatment may offer the best opportunity for future fertility. However, despite advancements in Assisted Reproductive Technology (ART), the uptake of fertility services in this group remains low. In this review, we highlighted the effect of all breast cancer treatments on women’s fertility, the effectiveness and safety of ART in breast cancer patients as well as the safety of pregnancy in breast cancer survivors. Our aim is to improve awareness of fertility preservation for breast cancer to ensure all women diagnosed with breast cancer have multidisciplinary approaches with early referral to fertility specialists to discuss regarding potential risks and benefits of fertility preservation to improve the uptake of fertility preservation among this group of patients.

Effects of Early-stage Phased Rehabilitation Training on Acute Respiratory Distress Syndrome:A Systematic Review and Meta-analysis

[Objectives]To systematically evaluate the effects of early-stage phased rehabilitation training on the oxygenation index,ICU length of stay,duration of mechanical ventilation,and occurrence of complications(ventilator-associated pneumonia,pressure ulcers,delirium)in ARDS patients,thus contributing evidence for the clinical application of early-stage phased rehabilitation training.[Methods]The China National Knowledge Infrastructure(CNKI),Wanfang,and other databases were searched.Literature screening,data extraction,and systematic analysis of the included studies were performed using Revman software.[Results]Thirteen randomized controlled trials involving a total of 860 patients were included in this review.The results of the meta-analysis showed that compared to the traditional rehabilitation training group,the early-stage phased rehabilitation training group demonstrated a significant increase in the oxygenation index of ARDS patients[SMD=1.18,95%CI(1.01,1.35),P<0.01],with statistically significant differences.Furthermore,there were significant reductions in ICU length of stay[SMD=-0.70,95%CI(-0.90,-0.50),P<0.01],duration of mechanical ventilation[SMD=-1.15,95%CI(-1.36,-0.94),P<0.01],and occurrence of complications[OR=0.16,95%CI(0.10,0.26),P<0.01],all of which were statistically significant.[Conclusions]Early-stage phased pulmonary rehabilitation training for ARDS patients effectively improves the oxygenation index,shortens ICU length of stay and duration of mechanical ventilation,and reduces complications.These findings support the clinical application and promotion of early-stage phased rehabilitation training.

Mechanical behavior and failure mechanisms of rock bolts subjected to static-dynamic loads

This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load frame to simulate various failure scenarios,pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined loads.The experimental results denote that with increased impact energy,maximum and average impact loads on rock bolts escalate significantly under pretension,initiating plastic deformation beyond a certain threshold.Despite minor reductions in the yield load due to impactinduced damage,pretension aids in constraining post-impact deformation rate and fluctuation degree of rock bolts.Moreover,impact-induced plastic deformation causes internal microstructure dislocation,fortifying the stiffness of the rock bolt support system.The magnitude of this fortification is directly related to the plastic deformation induced by the impact.These findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation,emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency.

Failure characterization of fully grouted rock bolts under triaxial testing

Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress conditions.Under these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is installed.In this study,a series of push tests was meticulously conducted under triaxial conditions.These tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock bolts.The results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/mm.The load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced stiffness.Notably,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 MPa.Additionally,the outcomes highlight an influence of confining stress on the lateral deformation of samples.Lower levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of shrinkage.Furthermore,diverse failure modes have been identified,intricately tied to the arrangement of confining stresses.Lower confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism.

Numerical Optimization by Finite Element Method of Stainless Steel/Glass-Epoxy Composite Bolted Joint under Tension and Compression

The aim of this study was to optimize the geometry and the design of metallic/composite single bolted joints subjected to tension-compression loading. For this purpose, it was necessary to evaluate the stress state in each component of the bolted join. The multi-material assembly was based on the principle of double lap bolted joint. It was composed of a symmetrical balanced woven glass-epoxy composite material plate fastened to two stainless sheets using a stainless pre-stressed bolt. In order to optimize the design and the geometry of the assembly, ten configurations were proposed and studied: a classical simple bolted joint, two joints with an insert (a BigHeadR insert and a stair one) embedded in the composite, two “waved” solutions, three symmetrical configurations composed of a succession of metallic and composites layers, without a sleeve, with one and with two sleeves, and two non-symmetrical constituted of metallic and composites layers associated with a stair-insert (one with a sleeve and one without). A tridimensional Finite Element Method (FEM) was used to model each configuration mentioned above. The FE models taked into account the different materials, the effects of contact between the different sheets of the assembly and the pre-stress in the bolt. The stress state was analyzed in the composite part. The concept of stress concentration factor was used in order to evaluate the stress increase in the highly stressed regions and to compare the ten configurations studied. For this purpose, three stress concentration factors were defined: one for a monotonic loading in tension, another for a monotonic loading in compression, and the third for a tension-compression cyclic loading. The results of the FEM computations showed that the use of alternative metallic and composite layers associated with two sleeves gived low values of stress concentration factors, smaller than 1.4. In this case, there was no contact between the bolt and the composite part and the most stressed region was not the vicinity of the hole but the end of the longest layers of the metallic inserts.

Fundamental principles of an effective reinforcing roof bolting strategy in horizontally layered roof strata and areas of potential improvement

It is arguable that the development of reinforcing roof bolting systems has largely stagnated in recent times, primarily due to the prevailing industry view that few, if any, further improvements can be made to what currently exists.However, this paper contends that reinforcing roof bolting systems can be further refined by considering both the specific manner by which horizontally bedded roof strata loses its natural self-supporting ability and the specific means by which reinforcing roof bolts act to promote or retain this natural self-supporting ability.The Australian coal industry has insisted on minimising bolt-hole diameter to maximise load transfer and on targeting full-encapsulation by any means necessary for many years.This has led to a significant, albeit unintended, consequence in terms of overall roof bolting effectiveness, namely increased resin pressures during bolt installation and the associated potential for opening bedding planes that may have, otherwise, remained closed during the bolt installation process.Given that the natural self-supporting ability of roof strata is strongly linked to whether bedding planes are open or closed, logically, minimising resin pressures should be a significant benefit.This paper focuses primarily on three key issues that relate directly to the function of the roof bolting system itself:(1) the importance of proper resin mixing in the context of maximising load transfer strength and stiffness,(2) the importance of minimising resin pressures developed during bolt installation, and(3) the importance of maximising the effectiveness of the available bolt pre-tension.All mine operators should be invested in improving the individual effectiveness of each installed roof bolt, even by relatively small incremental amounts, so this is an important topic for discussion within the mining community.

Principles of rockbolting design

This article introduces the principles of underground rockbolting design.The items discussed include underground loading conditions,natural pressure zone around an underground opening,design methodologies,selection of rockbolt types,determination of bolt length and spacing,factor of safety,and compatibility between support elements.Different types of rockbolting used in engineering practise are also presented.The traditional principle of selecting strong rockbolts is valid only in conditions of low in situ stresses in the rock mass.Energy-absorbing rockbolts are preferred in the case of high in situ stresses.A natural pressure arch is formed in the rock at a certain distance behind the tunnel wall.Rockbolts should be long enough to reach the natural pressure arch when the failure zone is small.The bolt length should be at least 1 m beyond the failure zone.In the case of a vast failure zone,tightly spaced short rockbolts are installed to establish an artificial pressure arch within the failure zone and long cables are anchored on the natural pressure arch.In this case,the rockbolts are usually less than 3 m long in mine drifts,but can be up to 7 m in large-scale rock caverns.Bolt spacing is more important than bolt length in the case of establishing an artificial pressure arch.In addition to the factor of safety,the maximum allowable displacement in the tunnel and the ultimate displacement capacity of rockbolts must be also taken into account in the design.Finally,rockbolts should be compatible with other support elements in the same support system in terms of displacement and energy absorption capacities.

Identification of QTLs Related to Bolting in Brassica rapa ssp. pekinensis (syn. Brassica campestris ssp. pekinensis)

A genetic linkage map of Brassica rapa ssp. pekinensis was constructed with 186 AFLP （amplified fragment length polymorphism） markers by using a doubled-haploid （DH） population with 183 individuals. The individuals were derived from F1 which was developed by crossing a bolting resistant DH line Y-177-12 and an easy bolting DH line Y195-93a. AFLPs were generated by the use of restriction enzymes EcoR Ⅰ and Mse Ⅰ . The segregation of each marker and linkage was analyzed by using JoinMap version 3.0. Mapped markers were aligned in ten linkage groups which covered 887.8 cM with an average marker interval of 4.47 cM. Markers showing skewed segregation ratio were clustered in six LGs. Quantitative trait loci （QTL） were mapped for bolting resistance by using MAPQTL 4.0 package. Four QTLs explaining from 7.0 to 9.4% of the total variation were detected, all of them increase bolting resistance. These mapped QTLs could be used to develop a marker assisted selection programme for bolting resistance breeding.

Differential gene expression profiling of gastric intraepithelial neoplasia and early-stage adenocarcinoma

AIM:To investigate the differentiated whole genome expression profiling of gastric high-and low-grade intraepithelial neoplasia and early-stage adenocarcinoma.METHODS:Gastric specimens from an upper magnifying chromoendoscopic targeted biopsy were collected from March 2010 to May 2013.Whole genome expression profiling was performed on 19 low-grade intraepithelial neoplasia(LGIN),20 high-grade intraepithelial neoplasia(HGIN),19 early-stage adenocarcinoma(EGC),and 19 chronic gastritis tissue samples using Agilent 4×44K Whole Human Genome microarrays.Differentially expressed genes between different types of lesions were identified using an unpaired t-test and corrected with the Benjamini and Hochberg false discovery rate algorithm.A gene ontology(GO)enrichment analysis was performed using the Gene Spring software GX 12.6.The differentially expressed gene was verified using a real-time TaqManPCR assay with independent tissue samples,including 26 LGIN,15 HGIN,14 EGC,and 20 chronic gastritis.The expression of G0S2 were further validated by immunohistochemical staining(IHC)in 24 LGIN,40 HGIN,30 EGC and 61 chronic gastritis specimens.RESULTS:The gene expression patterns of LGIN and HGIN tissues were distinct.There were 2521 significantly differentially expressed transcripts in HGIN,with951 upregulated and 1570 downregulated.A GO enrichment analysis demonstrated that the most striking overexpressed transcripts in HGIN compared with LGIN were in the category of metabolism,defense response,and nuclear factorκB(NF-κB)cascade.While the vast majority of transcripts had barely altered expression in HGIN and EGC tissues,only 38 transcripts were upregulated in EGC.A GO enrichment analysis revealed that the alterations of the immune response were most prominent in the progression from HGIN to EGC.It is worth noting that,compared with LGIN,289 transcriptswere expressed at higher levels both in HGIN and EGC.A characteristic gene,G0/G1 switch 2(G0S2)was one of the 289 transcripts and related to metabolism,the immune response,and the NF-κB cascade,and its expression was validated in independent samples through real-time TaqManPCR and immunohistochemical staining.In real-time PCR analysis,the expression of G0S2 was elevated both in HGIN and EGC compared with that in LGIN(P<0.01 and P<0.001,respectively).In IHC analysis,G0S2 immunoreactivity was detected in the cytoplasmic of neoplastic cells,but was undetectable in chronic gastritis cells.The G0S2 expression in HGIN was higher than that of LGIN(P=0.012,χ2=6.28)and EGC(P=0.008,χ2=6.94).CONCLUSION:A clear biological distinction between gastric high-and low-grade intraepithelial neoplasia was identified,and provides molecular evidence for clinical application.

Prediction of lymph node metastasis and sentinel node navigation surgery for patients with early-stage gastric cancer

Accurate prediction of lymph node(LN) status is crucially important for appropriate treatment planning in patients with early gastric cancer(EGC). However,consensus on patient and tumor characteristics associated with LN metastasis are yet to be reached. Through systematic search,we identified several independent variables associated with LN metastasis in EGC,which should be included in future research to assess which of these variables remain as significant predictors of LN metastasis. On the other hand,even if we use these promising parameters,we should realize the limitation and the difficulty of predicting LN metastasis accurately. The sentinel LN(SLN) is defined as first possible site to receive cancer cells along the route of lymphatic drainage from the primary tumor. The absence of metastasis in SLN is believed to correlate with the absence of metastasis in downstream LNs. In this review,we have attempted to focus on several independent parameters which have close relationship between tumor and LN metastasis in EGC. In addition,we evaluated the history of sentinel node navigation surgery and the usefulness for EGC.

Crosstalk of cold and gibberellin effects on bolting and flowering in flowering Chinese cabbage

The flower stalk is the product organ of flowering Chinese cabbage(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee),which is cultivated extensively in South China.Flower stalk formation and development,including bolting and flowering,determine the yield of flowering Chinese cabbage;however,the bolting and flowering mechanisms remain to be explored.To elucidate these processes,we studied the effects of low-temperature and gibberellin(GA)treatments,and their interaction,on stem elongation,bolting time,flowering time,hormone content,and cell morphology in stem of flowering Chinese cabbage.The results showed that both cold and GA treatments accelerated bolting time,stem elongation,and flowering time.Moreover,cold and GA cotreated plants displayed additive positive effects.In addition,cold treatments increased the GA,indole-3-acetic acid,and cytokinin contents and altered cell size in the shoot apices of flowering Chinese cabbage.Treatment with uniconazole,a GA synthesis inhibitor,strongly delayed bolting time,stem elongation,and flowering time,whereas GA,but not cold treatment,rescued this inhibition,indicating that low temperature accelerates bolting and flowering not only through inducing GA in the shoot apices,but also other ways.These results provide a theoretical basis for further dissecting the regulatory mechanism of bolting and flowering in flowering Chinese cabbage.

Effects of Rock Bolting on Stress Distribution around Tunnel Using the Elastoplastic Model

To ensure the stability of a tunnel during construction, rock bolts are usually installed, which affects the stress distribution around the tunnel. Therefore, it is necessary to study the effects of rock bolting on the stress distribution around the tunnel. In this article, the effects of rock bolting on the stress distribution around the tunnel, including the pesition and orientation of bolts, the overburden depths, and the bolt lengths, are simulated using the ANSYS software with an elnstoplastic model. The effect of multiple bolts of 2 m and 1 m lengths on the stress distribution in the roof and on the lateral sides of a tunnel and at different overburden depths is considered. An important finding is that the tensile stress region that is very dangerous for rock in the bottom of the tunnel grows rapidly with increasing overburden depths when rock bolts are installed only in the roof or on the lateral sides of a tunnel. The determination of the length of the rock bolt used around a tunnel is dependent on the loads and the integrity of the rock mass around the tunnel. In addition, rock bolting around the tunnel can obviously reduce the coefficients and the size of the region of stress concentration, especially when installed in high-stress areas. This fact is very important and essential for the design of tunnels and ensures engineering safety in tunnel engineering.

Treatment patterns for adjuvant docetaxel-based chemotherapy in early-stage breast cancer in China：A pooled retrospective analysis of four observational studies

Objective：Adjuvant docetaxel-based chemotherapy is frequently used for operable early breast cancer（EBC）.This study investigated patterns of use of docetaxel（T）in real-life clinical practice in China.Methods：This was a retrospective pooled analysis of the Asia-Pacific Breast Initiatives（APBI）Ⅰ（2006–2008）and Ⅱ（2009–2011）registries,and two Chinese observational studies;BC STATE（2011–2014）and BC Local Registry（2007–2010）.Female Chinese adults（≥18 years）with operable breast cancer treated with docetaxel-based adjuvant chemotherapy were included in the analysis.Patients with metastatic disease were excluded.The primary endpoint was assessment of treatment patterns and patient profiles.A logistic regression analysis was conducted to identify factors associated with choice of adjuvant chemotherapy regimen.Results：Data from 3,020 patients were included.The most frequently used adjuvant regimen was docetaxel/anthracycline combination[n=1,421（47.1%）;of whom 52.0%received T/epirubicin（E）/cyclophosphamide（C）],followed by docetaxel/other[n=705（23.3%）;of whom 72.8%received TC],docetaxel/anthracycline sequential[n=447（14.8%）;of whom 40.9%and 39.6%received 5-Fu/EC-T and EC-T,respectively],and＂other＂[n=447（14.8%）;of whom 91.5%received T].A significant association was found between adjuvant therapy with docetaxel/anthracycline combination and patient weight,menopausal status and estrogen receptor status.Conclusions：Real-world data revealed that docetaxel/anthracycline combination is the most commonly used category of docetaxel-based adjuvant therapy for patients with operable breast cancer in China;of which TEC is the most frequently used regimen.

Inheritance Analysis of Bolting Associated Traits Using Mixed Major Gene Plus Polygene Model in Brassica rapa

[ Objective ] This study aimed to analyze the inheritance of bolting associated traits in Brassica rapa, which will provide useful information in a breeding program for late-bolting or bolting-resistant cultivars of Chinese cabbage. [ Method] Three phenotypic measurements, bolting index, flowering time, days to 5 cm elongated stalk, respectively were used for inheritance analysis of six generations, P, （bolting resistant inbreed line ）, P2 （vernalization independent type） and their filial generations F1 , B1, B2 and F2, using the mixed major-gene plus polygene inheritance model. [ Result] The two traits, bolting index and days to 5 cm elongated stalk, both were controlled by two major genes with additive-dominant-epistatic effects （ B-1 model） in hybrid. The flowering time was controlled by one major gene with addltive-dominant effects plus additive-dominant-epistatic effects （D model）. The heritability of the major genes in B1, B2 and F2 were 96.22%, 93.33%, 93.55% for bolting index, 70.68%, 70.68%, 70.64% for flowering time, 79.44%, 79.55%, 79.38% for days to 5-cm elongated stalk, respectively, but no polygene heritability was detected in BI, B2 and F2 generation. It indicated that the bolting trait in Brassica rapa was controlled by one or tow major genes. [ Conclusion] This implied that in the genetic improvement for bolting resistant trait major gene was a main factor. It is fit for early selection and environment factor should be mentioned.

Clinicopathological analysis of early-stage breast cancer patients that meet indications for BRCA 1/2 genetic testing

Objective:To investigate the clinicopathological characteristics and prognostic factors of early-stage breast cancer patients with indications for breast cancer susceptibility genes 1/2(BRCA1/2)genetic testing in China.Methods:Based on the indication criteria for BRCA genetic testing specified in the National Comprehensive Cancer Network(NCCN)clinical practice guidelines in oncology,genetic/familial high-risk assessment:Breast and ovarian(Version 2.2019),a retrospective analysis was performed on patients with early-stage invasive breast cancer treated at Breast Disease Center,Peking University First Hospital between January 2008 and December 2016.Clinicopathological characteristics of all patients were analyzed,and prognoses were calculated using the KaplanMeier method and a Cox proportionate hazards model.Results:A total of 906 early-stage breast cancer patients who had indications for BRCA genetic testing and had complete clinicopathological data and follow-up information were included in the study group,accounting for34.7%of all breast cancer patients treated in Breast Disease Center,Peking University First Hospital during the study period.Compared with breast cancer patients without indications for BRCA genetic testing,the overall survival(OS)and disease-free survival(DFS)of patients with indications were not significantly different.In the study group,patients with premenopausal status,high T stage,lymph node positive,estrogen receptor(ER)negative,Ki-67>20%and presence of a vascular tumor thrombus had worse prognosis.There were more family histories of gastrointestinal cancer in patients with related indications than in patients without such indications.Conclusions:Single-center data showed that more than 30%of patients with early-stage breast cancer had indications for BRCA genetic testing.There was no prognostic difference in patients with or without indications for BRCA genetic testing.Premenopausal status,high T stage,lymph node positive,ER negative,Ki-67>20%,and presence of a vascular tumor thrombus were associated with poor prognosis.

Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress

In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.

A novel rock bolting system exploiting steel particles

The effectiveness of rock bolting in ground control has been extensively investigated,mainly for resin based systems.Alternative coupling materials are needed to have good mechanical performance and to reduce the economic impact.This study proposed a new bolting system exploiting steel particles as coupling material.The applicability of this system was assessed by laboratory and field pullout tests,assisted by digital imaging correlation(DIC),infrared thermography(IRT)and acoustic emission(AE).The results indicated that,for a 20 mm diameter bolt,the suitable steel particle size and corresponding inner diameter of borehole were 1.4 and 28 mm,respectively.For bolts installed in steel tubes,the particles improved the loading capacity compared to the resin bonded ones.Additional pullout tests on cement blocks indicated that steel particles can be effective for hard rock,whilst resin was a better choice for bolting of soft rock.Similar understanding was obtained by pullout tests in engineering fields,which demonstrated that the steel particles coupled bolts can provide favorable effects in hard rock mass,while the effects were negligible when installed in extremely soft coal mass.The wide set of multi-technique measurements helped to understand the mechanisms involved in the performance of the bolting system with coupling steel particles.