A simultaneous experimental and numerical study on crack propagation in the pre-cracked beams specimens(concrete-like materials)is carried out using three-point bending flexural test.The crack propagation and coalesce...A simultaneous experimental and numerical study on crack propagation in the pre-cracked beams specimens(concrete-like materials)is carried out using three-point bending flexural test.The crack propagation and coalescence paths of internal cracks in side beam specimens are experimentally studied by inserting double internal cracks.The effects of crack positions on the fracturing path in the bridge areas of the double cracked beam specimens are also studied.It has been observed that the breaking of concrete-like cracked beams specimens occurs mainly by the propagation of wing cracks emanating from the tips of the pre-existing cracks in the numerical and experimental analyses,respectively.The same specimens are numerically simulated by an indirect boundary element method(IBEM)known as displacement discontinuity method(DDM)using higher displacement discontinuity.These numerical results are compared with the existing experimental results.This comparison illustrates the higher accuracy of the results obtained by the indirect boundary element method by using only a small number of elements compared with the discrete element method(PFC2D code).展开更多
It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and ...It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content effect.The results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,respectively.The peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,respectively.The precracked rock with different water content is mainly characterized by tensile failure at different loading stages.However,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.展开更多
The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-ind...The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-induced cracks would initiate and propagate from the flaws,ultimately leading to the irreversible failure of rocks.To investigate the cracking behavior and the effect of flaw geometries on the mechanical properties of rock materials,a series of samples containing one,two and multiple flaws have been widely investigated in the laboratory.In this paper,the experimental results for pre-cracked rocks under quasistatic compression were systematically reviewed.The progressive failure process of intact rocks is briefly described to reveal the background for experiments on samples with flaws.Then,the nondestructive measurement techniques utilized in experiments,such as acoustic emission(AE),X-ray computed tomography(CT),and digital image correlation(DIC),are summarized.The mechanical characteristics of rocks with different flaw geometries and under different loading conditions,including the geometry of pre-existing flaws,flaw filling condition and confining pressure,are discussed.Furthermore,the cracking process is evaluated from the perspective of crack initiation,coalescence,and failure patterns.展开更多
To investigate the mechanical properties of concrete under the leakage condition for a liquefied natural gas storage tank,cryogenic freeze-thaw cycle tests were performed under liquid nitrogen refrigeration and water ...To investigate the mechanical properties of concrete under the leakage condition for a liquefied natural gas storage tank,cryogenic freeze-thaw cycle tests were performed under liquid nitrogen refrigeration and water immersion melting.The effects of the cryogenic temperature,freeze-thaw cycle,pre-crack,and addition of steel fiber on the compressive strength,flexural strength,and splitting tensile concrete strength were analyzed.The experimental results show that the width of pre-cracks tends to expand after freeze-thaw cycles.When the freezing temperature is -80℃,the relative width of the pre-cracks expands by 1 to 2 times.However,when the freezing temperature is -120℃,the relative width of the pre-cracks expands by 2 to 5 times.Compared with the specimens without steel fibers,the specimens with steel fibers can still maintain a relatively complete appearance structure after the mechanical property tests.The compressive strength,flexural strength,and splitting tensile concrete strength decrease with the drop in the freezing temperature.After adding steel fibers,all of the three strengths increased.展开更多
BACKGROUND Endoscopic submucosal dissection(ESD)is a standardized therapeutic approach for early carcinoma of the digestive tracts.In this regard,the process of histopathological diagnosis requires standardization.How...BACKGROUND Endoscopic submucosal dissection(ESD)is a standardized therapeutic approach for early carcinoma of the digestive tracts.In this regard,the process of histopathological diagnosis requires standardization.However,the uneven development of healthcare in China,especially in eastern and western China,creates challenges for sharing a standardized diagnostic process.AIM To optimize the process of ESD specimen sampling,embedding and slide production,and to provide complete and accurate pathological reports.METHODS We established a practical process of specimen sampling,created standardized reporting templates,and trained pathologists from neighboring hospitals and those in the western region.A training effectiveness survey was conducted,and the collected data were assessed by the corresponding percentages.RESULTS A total of 111 valid feedback forms have been received,among which 58%of the participants obtained photographs during specimen collection,whereas the percentage increased to 79%after training.Only 58%and 62%of the respondents ensured the mucosal tissue strips were flat and their order remained unchanged;after training,these two proportions increased to 95%and 92%,respectively.Approximately half the participants measured the depth of the submucosal infiltration,which significantly increased to 95%after training.The percentage of pathologists who did not evaluate lymphovascular invasion effectively reduced.Only 22%of the participants had fixed clinic-pathological meetings before training,which increased to 49%after training.The number of participants who had a thorough understanding of endoscopic diagnosis also significantly increased.CONCLUSION There have been significant improvements in the process of specimen collection,section quality,and pathology reporting in trained hospitals.Therefore,our study provides valuable insights for others facing similar challenges.展开更多
Deep hole pre-cracking blasting(DHPB)technology is the preferred means of preventing and controlling rockburst induced by hard-thick rock layers in coal mines.When DHPB is applied to hard-thick rock layers,the insuffi...Deep hole pre-cracking blasting(DHPB)technology is the preferred means of preventing and controlling rockburst induced by hard-thick rock layers in coal mines.When DHPB is applied to hard-thick rock layers,the insufficient knowledge about the crack extension scale under different rock properties and blasting parameters may result in undesirable pressure relief.Therefore,LS-DYNA was adopted to analyse the crack extension characteristics under the combined effect of rock tensile strength,explosive density,blasthole spacing,and decoupled coefficient.The Holmquist–Johnson–Cook model(HJC),verified by the results of blasting experiment and numerical simulation in literature,was used to characterise coal-bearing rocks.Numerical analysis was conducted to study the blasting crack extension and fractal damage for rock tensile strength,explosive densities,blasthole spacing,and decoupled coefficients.The results show that the tensile strength of rock is the key factor for blasting design.The fractal damage caused by blasting increases when the tensile strength of rock decreases.For rocks with lower tensile strength,more blasting energy is consumed by the increasing damage area in the crushed zone.Higher explosive density can promote the development of blasting cracks and increase fractal damage,but the increasing range of the crushed zone also wastes a large amount of energy.As the blasthole spacing increases,the fractal damage decreases,and the crack extension scale in the fractured zone first increases and then decreases,and eventually remains almost unchanged.An optimum interval exists for the decoupled coefficient,and the full utilization of explosive energy within the interval leads to penetrating blast cracks and smaller crushed zones.Based on the simulation results,the optimal blasting parameters for coarse sandstone were validated in the field practice.Monitoring data show that the optimized blasting significantly reduces the risk of rockburst.展开更多
The objective of this study is to evaluate the efficacy of laparoscopic surgery combined with the rectal inversion and specimen extraction(RIES)technique for rectal cancer,focusing on both short-term and long-term out...The objective of this study is to evaluate the efficacy of laparoscopic surgery combined with the rectal inversion and specimen extraction(RIES)technique for rectal cancer,focusing on both short-term and long-term outcomes.A retrospective comparative analysis was performed on 120 patients who underwent laparoscopic radical excision for rectal cancer from June 2017 to June 2021.Patients were categorized into two groups:Group RIES(n=58),which received the novel RIES technique,and Group AIES(n=62),which underwent the conventional abdominal incision for specimen extraction.Short-term outcomes,such as postoperative pelvic sepsis,temporary ileus,anastomotic leakage,and anastomotic stricture,were meticulously recorded.Longterm efficacy was evaluated through the 3-year overall survival(OS),disease-free survival(DFS),and local recurrence rate(LRR).The RIES group demonstrated a 3-year OS,DFS,and LRR of 86.2%,77.6%,and 8.6%,respectively,with a low incidence of short-term complications.Comparatively,the AIES group showed a 3-year OS,DFS,and LRR of 83.9%,74.2%,and 19.4%,respectively,with slightly higher rates of postoperative complications.Statistical analysis using the Student's t-test,the chi-square(χ^(2))test revealed no significant differences in the primary outcomes between the two groups,and suggested the noninferiority of the RIES technique.The study suggests that the RIES technique is a safe,feasible,and potentially functional and oncological superior approach to rectal cancer treatment,without compromising clinical efficacy.Further research is warranted to validate thesefindings in a larger,multicenter,and randomized controlled trial.展开更多
The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geo...The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geometrically induced stress gradients in the test region.Experimental data on CCF life and strain responses of ZSGH4169 alloy are acquired under different CCF loads.The Maximum Strain within Each(MSE)CCF cycle is demonstrated to be independent of the Low-Cycle Fatigue(LCF)loads and High-Cycle Fatigue(HCF)stress amplitudes,but exhibits a correlation with the Cycle Ratio of HCF/LCF(Rf).The growth law of MSE changes from linear to logarithmic as Rfdecreases.Strain amplitudes in the dwell stage,observed unaffected by Rf,are quantified as a function of LCF nominal stresses and HCF stress amplitudes.However,under a defined CCF load,strain amplitudes in the dwell stage remain constant.Strain peaks in the dwell stage in a single CCF cycle decrease in a power function with increasing HCF cycles.展开更多
Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse s...Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.展开更多
Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was...Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied. Methods Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistances to temperature and UV irradiation were analyzed. A total of 106 TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infectionn. Results The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4℃, at room temperature (20℃) and at 37℃ for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56℃, at 67℃ and at 75℃, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. Conclusion The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.展开更多
AIM: To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection.METHODS: A prospectively designed database of a consecutive series of patients undergo...AIM: To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection.METHODS: A prospectively designed database of a consecutive series of patients undergoing laparoscopic low anterior resection for rectal cancer with various tumor-node-metastasis classi?cations from March 2011 to February 2012 at the First Affiliated Hospital of Sun Yat-Sen University was analyzed. Patient selection for transanal specimen extraction and intracorporeal anastomosis was made on the basis of tumor size and distance of rectal lesions from the anal verge. Demographic data, operative parameters, and postoperative outcomes were assessed.RESULTS: None of the patients was converted to laparotomy. Respectively, there were 16 cases in the low anastomosis and five in the ultralow anastomosis groups. Mean age of the patients was 45.4 years, and mean body mass index was 23.1 kg/m2. Mean distance of the lower edge of the lesion from the anal verge was 8.3 cm. Mean operating time was 132 min, and mean intraoperative blood loss was 84 mL. According to the principle of rectal cancer surgery, we performed D2 lymph node dissection in 13 cases and D3 in eight. Mean lymph nodes harvest was 17.8, and the number of positive lymph nodes was 3.4. Median hospital stay was 6.7 d. No serious postoperative complication occurred except for one anastomotic leakage. All patients remained disease free. Mean Wexner score was 3.7 at 11 mo after the operation.CONCLUSION: Transanal NOSE for total laparoscopic low/ultralow anterior resection is feasible, safe and oncologically sound. Further studies with long-term outcomes are needed to explore its potential advantages.展开更多
AIM: To describe the application of complete robotic gastrectomy with transvaginal specimen extraction(TVSE) for gastric cancer patients.METHODS: Between July and November 2014, eight female patients who were diagnose...AIM: To describe the application of complete robotic gastrectomy with transvaginal specimen extraction(TVSE) for gastric cancer patients.METHODS: Between July and November 2014, eight female patients who were diagnosed with gastric adenocarcinoma underwent a TVSE following a full robot-sewn gastrectomy. According to the tumor location, the patients were allocated to two different groups; two patients received robotic total gastrectomy with TVSE and the other six received robotic distal gastrectomy with TVSE.RESULTS: Surgical procedures were successfully performed in all eight cases without conversion. The mean age was 55.3(range, 42-69) years, and the mean body mass index was 23.2(range, 21.6-26.0) kg/m2. The mean total operative time and blood loss were 224(range, 200-298) min and 62.5(range, 50-150) m L, respectively. The mean postoperative hospital stay was 3.6(range, 3-5) d. The mean number of lymph nodes resected was 23.6(range, 17-27). None was readmitted within 30 d of postoperation. During the follow-up, no stricture developed nor was any anastomotic leakage detected.CONCLUSION: It is possible to perform a TVSE following a full robot-sewn gastrectomy with standard D2 lymph node resection for female gastric cancer patients.展开更多
AIM:To introduce transvaginal or transanal specimen extraction in laparoscopic total mesorectal excision surgery to avoid an abdominal incision. METHODS:Between January 2009 and December 2011,21 patients with rectal c...AIM:To introduce transvaginal or transanal specimen extraction in laparoscopic total mesorectal excision surgery to avoid an abdominal incision. METHODS:Between January 2009 and December 2011,21 patients with rectal cancer underwent laparoscopic radical resection and the specimen was retrieved by two different ways:transvaginal or transanal rectal removal.Transvaginal specimen extraction approach was strictly limited to elderly post-menopausal women who need hysterectomy.Patients aged between 30 and 80 years,with a body mass index of less than 30 kg/m2, underwent elective surgery.The surgical technique and the outcomes related to the specimen extraction,such as duration of surgery,length of hospital stay,and the complications were retrospectively reviewed. RESULTS:Laparoscopic resection using a natural orifice removal approach was successful in all of the 21 patients.Median operating time was 185 min(range,122-260 min)and the estimated blood loss was 48 mL. The mean length of hospital stay was 7.5 d(range,2-11 d).One patient developed postoperative ileus and had an extended hospital stay.The patient complained of minimal pain.There were no postoperative complications or surgery-associated death.The mean size of the lesion was 2.8 cm(range,1.8-6.0 cm),and the mean number of lymph nodes harvested was 18.7(range, 8-27).At a mean follow-up of 20.6 mo(range,10-37 mo),there were no functional disorders associated with the transvaginal and transanal specimen extraction. CONCLUSION:Transvaginal or transanal extraction in L-TME is a safe and effective procedure.Natural orifice specimen extraction can avoid the abdominal wall incision and its potential complications.展开更多
AIM: To investigate the prevalence and implications of unusual histopathological findings in appendectomy specimens from patients with suspected acute appendicitis. METHODS: The demographic and histopathological data ...AIM: To investigate the prevalence and implications of unusual histopathological findings in appendectomy specimens from patients with suspected acute appendicitis. METHODS: The demographic and histopathological data of 1621 patients (≥ 16 years-old) who underwent appendectomy to treat an initial diagnosis of acute appendicitis between January 1999 and November 2011 were retrospectively assessed. Microscopic findings were used to classify the patients under six categories: appendix vermiformis, phlegmonous appendicitis, gan- grenous appendicitis, perforated appendicitis, supurative appendicitis, and unusual histopathologic findings. The demographic and clinicopathologic characteristics of patients with unusual histopathologic findings were evaluated in detail, and re-analysis of archived resected appendix specimens was carried out. RESULTS: A total of 912 males and 709 females, from16 to 94 years old, were included in the study and comprised 789 cases of suppurative appendicitis, 370 cases of appendix vermiformis, 243 cases of perforated gangrenous appendicitis, 53 cases of flegmaneous appendicitis, 32 cases of gangrenous appendicitis, and 134 (8.3%) cases of unusual histopathological findings. The unusual histopathological findings included fibrous obliteration (n = 62), enterobius vermicularis (n = 31), eosinophilic infiltration (n = 10), mucinous cystadenoma (n = 8), carcinoid tumor (n = 6), granulomatous inflammation (n = 5), adenocarcinoma (n = 4; one of them mucinous), and mucocele (n = 3), adenomatous polyp (n = 1), taenia sup (n = 1), ascaris lumbricoides (n = 1), appendiceal diverticula (n = 1), and B cell non-hodgkin lymphoma (n = 1). None of the 11 patients with subsequent diagnosis of tumor were suspected of cancer prior to the appendectomy. CONCLUSION: Even when the macroscopic appearance of appendectomy specimens is normal, histopathological assessment will allow early diagnosis of many unusual diseases.展开更多
BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for l...BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for low rectal cancer.AIM To further explore the application value of the transanal placement of the anvil and to evaluate the short-term efficacy of NOSES for resecting specimens of low rectal cancer, as well as to provide a theoretical basis for its extensive clinical application.METHODS From June 2015 to June 2018, 108 consecutive laparoscopic-assisted low rectal cancer resections were performed at our center. Among them, 26 specimens were resected transanally using a prolapsing technique(NOSES), and 82 specimens were resected through a conventional abdominal wall small incision(LAP). A propensity score matching method was used to select 26 pairs of matched patients, and their perioperative data were analyzed.RESULTS The baseline data were comparable between the two matched groups. All 52 patients underwent the surgery successfully. The operative time, blood loss,number of harvested lymph nodes, postoperative complication rate,circumferential margin involvement, postoperative follow-up data, and postoperative anal function were not statistically significant. The NOSES group had shorter time to gastrointestinal function recovery(2.6 ± 1.0 d vs 3.4 ± 0.9 d, P= 0.006), shorter postoperative hospital stay(7.1 ± 1.7 d vs 8.3 ± 1.1 d, P = 0.003),lower pain score(day 1: 2.7 ± 1.8 vs 4.6 ± 1.9, day 3: 2.0 ± 1.1 vs 4.1 ± 1.2, day 5: 1.7± 0.9 vs 3.3 ± 1.0, P < 0.001), a lower rate of additional analgesic use(11.5% vs61.5%, P = 0.001), and a higher satisfaction rate in terms of the aesthetic appearance of the abdominal wall after surgery(100% vs 23.1%, P < 0.001).CONCLUSION NOSES for low rectal cancer can achieve satisfactory short-term efficacy and has advantages in reducing postoperative pain, shortening the length of postoperative hospital stay, and improving patients' satisfaction in terms of a more aesthetic appearance of the abdominal wall.展开更多
Over the last 20 years, laparoscopic colorectal surgery has shown equal efficacy for benign and malignant colorectal diseases when compared to open surgery. However, a laparoscopic approach reduces postoperative morbi...Over the last 20 years, laparoscopic colorectal surgery has shown equal efficacy for benign and malignant colorectal diseases when compared to open surgery. However, a laparoscopic approach reduces postoperative morbidity and shortens hospital stay. In the quest to optimize outcomes after laparoscopic colorectal surgery, reduction of access trauma could be a way to improve recovery. To date, one method to reduce access trauma is natural orifice specimen extraction(NOSE). NOSE aims to reduce access trauma in laparoscopic colorectal surgery. The specimen is delivered via a natural orifice and the anastomosis is created intracorporeally. Different methods are used to extract the specimen and to create a bowel anastomosis. Currently, specimens are delivered transcolonically, transrectally, transanally, or transvaginally. Each of these NOSEprocedures raises specific issues with regard to operative technique and application. The presumed benefits of NOSE-procedures are less pain, lower analgesia requirements, faster recovery, shorter hospital stay, better cosmetic results, and lower incisional hernia rates. Avoidance of extraction site laparotomy is the most important characteristic of NOSE. Concerns associated with the NOSE-technique include bacterial contamination of the peritoneal cavity, inflammatory response, and postoperative outcomes, including postoperative pain and the functional and oncologic outcomes. These issues need to be studied in prospective randomized controlled trials. The aim of this systematic review is to describe the role of NOSE in minimally invasive colorectal surgery.展开更多
This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effec...This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effects sensitive to microstructures including the specimen thickness, grain size and a ratio between them are highlighted to summarize some general rules for size effects. Then, ongoing research progress and new challenges in evaluating the fatigue performance of additive manufactured parts controlled by location-specific defects, microstructure heterogeneities as well as mechanical anisotropy using miniature specimen testing technique are discussed and addressed. Finally, a potential roadmap to establish a data-driven evaluation platform based on a large number of miniature specimen-based experiment data,theoretical computations and the ’big data’ analysis with machine learning is proposed. It is expected that this overview would provide a novel strategy for the realistic evaluation and fast qualification of fatigue properties of additive manufactured parts we have been facing to.展开更多
AIM: To investigate how complete laparoscopic anterior resection with natural orifice specimen extraction (NOSE), as a novel minimally invasive surgery, compares to conventional laparoscopic surgery.
Objective To provide a feasible and cost-effective next-generation sequencing （NGS） method for accurate identification of viral pathogens in clinical specimens, because enormous limitations impede the clinical use o...Objective To provide a feasible and cost-effective next-generation sequencing （NGS） method for accurate identification of viral pathogens in clinical specimens, because enormous limitations impede the clinical use of common NGS, such as high cost, complicated procedures, tremendous data analysis, and high background noise in clinical samples. Methods Viruses from cell culture materials or clinical specimens were identified following an improved NGS procedure： reduction of background noise by sample preprocessing, viral enrichment by barcoded oligonucleotide （random hexamer or non-ribosomal hexanucleotide） primer-based amplification, fragmentation-free library construction and sequencing of one-tube mixtures, as well as rapid data analysis using an in-house pipeline. Results NGS data demonstrated that both barcoded primer sets were useful to simultaneously capture multiple viral pathogens in cell culture materials or clinical specimens and verified that hexanucleotide primers captured as many viral sequences as hexamers did. Moreover, direct testing of clinical specimens using this improved hexanucleotide primer-based NGS approach provided further detailed genotypes of enteroviruses causing hand, foot, and mouth disease （HFMD） and identified other potential viruses or differentiated misdiagnosis events. Conclusion The improved barcoded oligonucleotide primer-based NGS approach is simplified, time saving, cost effective, and appropriate for direct identification of viral pathogens in clinical practice.展开更多
文摘A simultaneous experimental and numerical study on crack propagation in the pre-cracked beams specimens(concrete-like materials)is carried out using three-point bending flexural test.The crack propagation and coalescence paths of internal cracks in side beam specimens are experimentally studied by inserting double internal cracks.The effects of crack positions on the fracturing path in the bridge areas of the double cracked beam specimens are also studied.It has been observed that the breaking of concrete-like cracked beams specimens occurs mainly by the propagation of wing cracks emanating from the tips of the pre-existing cracks in the numerical and experimental analyses,respectively.The same specimens are numerically simulated by an indirect boundary element method(IBEM)known as displacement discontinuity method(DDM)using higher displacement discontinuity.These numerical results are compared with the existing experimental results.This comparison illustrates the higher accuracy of the results obtained by the indirect boundary element method by using only a small number of elements compared with the discrete element method(PFC2D code).
基金financially supported by National Natural Science Foundation of China(No.52304136)Young Talent of Lifting Engineering for Science and Technology in Shandong,China(No.SDAST2024QTA060)Key Project of Research and Development in Liaocheng(No.2023YD02)。
文摘It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass.Based on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content effect.The results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,respectively.The peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,respectively.The precracked rock with different water content is mainly characterized by tensile failure at different loading stages.However,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.
基金financial support from the National Key R&D Program of China(Grant No.2020YFA0711802)。
文摘The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-induced cracks would initiate and propagate from the flaws,ultimately leading to the irreversible failure of rocks.To investigate the cracking behavior and the effect of flaw geometries on the mechanical properties of rock materials,a series of samples containing one,two and multiple flaws have been widely investigated in the laboratory.In this paper,the experimental results for pre-cracked rocks under quasistatic compression were systematically reviewed.The progressive failure process of intact rocks is briefly described to reveal the background for experiments on samples with flaws.Then,the nondestructive measurement techniques utilized in experiments,such as acoustic emission(AE),X-ray computed tomography(CT),and digital image correlation(DIC),are summarized.The mechanical characteristics of rocks with different flaw geometries and under different loading conditions,including the geometry of pre-existing flaws,flaw filling condition and confining pressure,are discussed.Furthermore,the cracking process is evaluated from the perspective of crack initiation,coalescence,and failure patterns.
文摘To investigate the mechanical properties of concrete under the leakage condition for a liquefied natural gas storage tank,cryogenic freeze-thaw cycle tests were performed under liquid nitrogen refrigeration and water immersion melting.The effects of the cryogenic temperature,freeze-thaw cycle,pre-crack,and addition of steel fiber on the compressive strength,flexural strength,and splitting tensile concrete strength were analyzed.The experimental results show that the width of pre-cracks tends to expand after freeze-thaw cycles.When the freezing temperature is -80℃,the relative width of the pre-cracks expands by 1 to 2 times.However,when the freezing temperature is -120℃,the relative width of the pre-cracks expands by 2 to 5 times.Compared with the specimens without steel fibers,the specimens with steel fibers can still maintain a relatively complete appearance structure after the mechanical property tests.The compressive strength,flexural strength,and splitting tensile concrete strength decrease with the drop in the freezing temperature.After adding steel fibers,all of the three strengths increased.
基金Supported by the Medical Education Research Project from Nanjing Drum Tower Hospital,No.2021-7the Clinical Trials Fund from Nanjing Drum Tower Hospital,No.2022-YXZX-XH-04National Natural Science Foundation of China,No.82203063.
文摘BACKGROUND Endoscopic submucosal dissection(ESD)is a standardized therapeutic approach for early carcinoma of the digestive tracts.In this regard,the process of histopathological diagnosis requires standardization.However,the uneven development of healthcare in China,especially in eastern and western China,creates challenges for sharing a standardized diagnostic process.AIM To optimize the process of ESD specimen sampling,embedding and slide production,and to provide complete and accurate pathological reports.METHODS We established a practical process of specimen sampling,created standardized reporting templates,and trained pathologists from neighboring hospitals and those in the western region.A training effectiveness survey was conducted,and the collected data were assessed by the corresponding percentages.RESULTS A total of 111 valid feedback forms have been received,among which 58%of the participants obtained photographs during specimen collection,whereas the percentage increased to 79%after training.Only 58%and 62%of the respondents ensured the mucosal tissue strips were flat and their order remained unchanged;after training,these two proportions increased to 95%and 92%,respectively.Approximately half the participants measured the depth of the submucosal infiltration,which significantly increased to 95%after training.The percentage of pathologists who did not evaluate lymphovascular invasion effectively reduced.Only 22%of the participants had fixed clinic-pathological meetings before training,which increased to 49%after training.The number of participants who had a thorough understanding of endoscopic diagnosis also significantly increased.CONCLUSION There have been significant improvements in the process of specimen collection,section quality,and pathology reporting in trained hospitals.Therefore,our study provides valuable insights for others facing similar challenges.
基金funded by the projects:National Natural Science Foundation of China(52274098,U21A20110)National key research and development program(2022YFC3004603)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_2798)Graduate Innovation Program of China University of Mining and Technology(2023WLKXJ036).
文摘Deep hole pre-cracking blasting(DHPB)technology is the preferred means of preventing and controlling rockburst induced by hard-thick rock layers in coal mines.When DHPB is applied to hard-thick rock layers,the insufficient knowledge about the crack extension scale under different rock properties and blasting parameters may result in undesirable pressure relief.Therefore,LS-DYNA was adopted to analyse the crack extension characteristics under the combined effect of rock tensile strength,explosive density,blasthole spacing,and decoupled coefficient.The Holmquist–Johnson–Cook model(HJC),verified by the results of blasting experiment and numerical simulation in literature,was used to characterise coal-bearing rocks.Numerical analysis was conducted to study the blasting crack extension and fractal damage for rock tensile strength,explosive densities,blasthole spacing,and decoupled coefficients.The results show that the tensile strength of rock is the key factor for blasting design.The fractal damage caused by blasting increases when the tensile strength of rock decreases.For rocks with lower tensile strength,more blasting energy is consumed by the increasing damage area in the crushed zone.Higher explosive density can promote the development of blasting cracks and increase fractal damage,but the increasing range of the crushed zone also wastes a large amount of energy.As the blasthole spacing increases,the fractal damage decreases,and the crack extension scale in the fractured zone first increases and then decreases,and eventually remains almost unchanged.An optimum interval exists for the decoupled coefficient,and the full utilization of explosive energy within the interval leads to penetrating blast cracks and smaller crushed zones.Based on the simulation results,the optimal blasting parameters for coarse sandstone were validated in the field practice.Monitoring data show that the optimized blasting significantly reduces the risk of rockburst.
文摘The objective of this study is to evaluate the efficacy of laparoscopic surgery combined with the rectal inversion and specimen extraction(RIES)technique for rectal cancer,focusing on both short-term and long-term outcomes.A retrospective comparative analysis was performed on 120 patients who underwent laparoscopic radical excision for rectal cancer from June 2017 to June 2021.Patients were categorized into two groups:Group RIES(n=58),which received the novel RIES technique,and Group AIES(n=62),which underwent the conventional abdominal incision for specimen extraction.Short-term outcomes,such as postoperative pelvic sepsis,temporary ileus,anastomotic leakage,and anastomotic stricture,were meticulously recorded.Longterm efficacy was evaluated through the 3-year overall survival(OS),disease-free survival(DFS),and local recurrence rate(LRR).The RIES group demonstrated a 3-year OS,DFS,and LRR of 86.2%,77.6%,and 8.6%,respectively,with a low incidence of short-term complications.Comparatively,the AIES group showed a 3-year OS,DFS,and LRR of 83.9%,74.2%,and 19.4%,respectively,with slightly higher rates of postoperative complications.Statistical analysis using the Student's t-test,the chi-square(χ^(2))test revealed no significant differences in the primary outcomes between the two groups,and suggested the noninferiority of the RIES technique.The study suggests that the RIES technique is a safe,feasible,and potentially functional and oncological superior approach to rectal cancer treatment,without compromising clinical efficacy.Further research is warranted to validate thesefindings in a larger,multicenter,and randomized controlled trial.
基金co-supported by the National Natural Science Foundation of China(51805017)National Science and Technology Project(J2017-IV-0012-0049)+1 种基金National Science and Technology Project,China(J2019-IV-0007-0075)the Fundamental Research Funds for the Central Universities,China(JKF-20240036).
文摘The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geometrically induced stress gradients in the test region.Experimental data on CCF life and strain responses of ZSGH4169 alloy are acquired under different CCF loads.The Maximum Strain within Each(MSE)CCF cycle is demonstrated to be independent of the Low-Cycle Fatigue(LCF)loads and High-Cycle Fatigue(HCF)stress amplitudes,but exhibits a correlation with the Cycle Ratio of HCF/LCF(Rf).The growth law of MSE changes from linear to logarithmic as Rfdecreases.Strain amplitudes in the dwell stage,observed unaffected by Rf,are quantified as a function of LCF nominal stresses and HCF stress amplitudes.However,under a defined CCF load,strain amplitudes in the dwell stage remain constant.Strain peaks in the dwell stage in a single CCF cycle decrease in a power function with increasing HCF cycles.
基金Funded by the National Natural Science Foundation of China(Nos.52278518 and 51938011)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.24KJB560021)。
文摘Based on the split hopkinson pressure bar(SHPB)tests results,the cubic specimens have been numerically modeled in this paper to investigate the impact of key factors,such as the rise time,duration,and incident pulse shape,on achieving stress uniformity.After analysis,the paper provides actionable methods aimed at optimizing the conditions for stress uniformity within the cubic specimen.Finally,the lateral inertia effect of cubic specimen has been scrutinized to address the existing gap in this academic area.
基金This work was supported by the National High-Technology Research and Development Program of China (863 Program) 2003AA208402.
文摘Objective The causal agent for SARS is considered as a novel coronavirus that has never been described both in human and animals previously. The stability of SARS coronavirus in human specimens and in environments was studied. Methods Using a SARS coronavirus strain CoV-P9, which was isolated from pharyngeal swab of a probable SARS case in Beijing, its stability in mimic human specimens and in mimic environment including surfaces of commonly used materials or in household conditions, as well as its resistances to temperature and UV irradiation were analyzed. A total of 106 TCID50 viruses were placed in each tested condition, and changes of the viral infectivity in samples after treatments were measured by evaluating cytopathic effect (CPE) in cell line Vero-E6 at 48 h after infectionn. Results The results showed that SARS coronavirus in the testing condition could survive in serum, 1:20 diluted sputum and feces for at least 96 h, whereas it could remain alive in urine for at least 72 h with a low level of infectivity. The survival abilities on the surfaces of eight different materials and in water were quite comparable, revealing reduction of infectivity after 72 to 96 h exposure. Viruses stayed stable at 4℃, at room temperature (20℃) and at 37℃ for at least 2 h without remarkable change in the infectious ability in cells, but were converted to be non-infectious after 90-, 60- and 30-min exposure at 56℃, at 67℃ and at 75℃, respectively. Irradiation of UV for 60 min on the virus in culture medium resulted in the destruction of viral infectivity at an undetectable level. Conclusion The survival ability of SARS coronavirus in human specimens and in environments seems to be relatively strong. Heating and UV irradiation can efficiently eliminate the viral infectivity.
文摘AIM: To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection.METHODS: A prospectively designed database of a consecutive series of patients undergoing laparoscopic low anterior resection for rectal cancer with various tumor-node-metastasis classi?cations from March 2011 to February 2012 at the First Affiliated Hospital of Sun Yat-Sen University was analyzed. Patient selection for transanal specimen extraction and intracorporeal anastomosis was made on the basis of tumor size and distance of rectal lesions from the anal verge. Demographic data, operative parameters, and postoperative outcomes were assessed.RESULTS: None of the patients was converted to laparotomy. Respectively, there were 16 cases in the low anastomosis and five in the ultralow anastomosis groups. Mean age of the patients was 45.4 years, and mean body mass index was 23.1 kg/m2. Mean distance of the lower edge of the lesion from the anal verge was 8.3 cm. Mean operating time was 132 min, and mean intraoperative blood loss was 84 mL. According to the principle of rectal cancer surgery, we performed D2 lymph node dissection in 13 cases and D3 in eight. Mean lymph nodes harvest was 17.8, and the number of positive lymph nodes was 3.4. Median hospital stay was 6.7 d. No serious postoperative complication occurred except for one anastomotic leakage. All patients remained disease free. Mean Wexner score was 3.7 at 11 mo after the operation.CONCLUSION: Transanal NOSE for total laparoscopic low/ultralow anterior resection is feasible, safe and oncologically sound. Further studies with long-term outcomes are needed to explore its potential advantages.
文摘AIM: To describe the application of complete robotic gastrectomy with transvaginal specimen extraction(TVSE) for gastric cancer patients.METHODS: Between July and November 2014, eight female patients who were diagnosed with gastric adenocarcinoma underwent a TVSE following a full robot-sewn gastrectomy. According to the tumor location, the patients were allocated to two different groups; two patients received robotic total gastrectomy with TVSE and the other six received robotic distal gastrectomy with TVSE.RESULTS: Surgical procedures were successfully performed in all eight cases without conversion. The mean age was 55.3(range, 42-69) years, and the mean body mass index was 23.2(range, 21.6-26.0) kg/m2. The mean total operative time and blood loss were 224(range, 200-298) min and 62.5(range, 50-150) m L, respectively. The mean postoperative hospital stay was 3.6(range, 3-5) d. The mean number of lymph nodes resected was 23.6(range, 17-27). None was readmitted within 30 d of postoperation. During the follow-up, no stricture developed nor was any anastomotic leakage detected.CONCLUSION: It is possible to perform a TVSE following a full robot-sewn gastrectomy with standard D2 lymph node resection for female gastric cancer patients.
基金Supported by Jilin University,China,No.3R211P163428
文摘AIM:To introduce transvaginal or transanal specimen extraction in laparoscopic total mesorectal excision surgery to avoid an abdominal incision. METHODS:Between January 2009 and December 2011,21 patients with rectal cancer underwent laparoscopic radical resection and the specimen was retrieved by two different ways:transvaginal or transanal rectal removal.Transvaginal specimen extraction approach was strictly limited to elderly post-menopausal women who need hysterectomy.Patients aged between 30 and 80 years,with a body mass index of less than 30 kg/m2, underwent elective surgery.The surgical technique and the outcomes related to the specimen extraction,such as duration of surgery,length of hospital stay,and the complications were retrospectively reviewed. RESULTS:Laparoscopic resection using a natural orifice removal approach was successful in all of the 21 patients.Median operating time was 185 min(range,122-260 min)and the estimated blood loss was 48 mL. The mean length of hospital stay was 7.5 d(range,2-11 d).One patient developed postoperative ileus and had an extended hospital stay.The patient complained of minimal pain.There were no postoperative complications or surgery-associated death.The mean size of the lesion was 2.8 cm(range,1.8-6.0 cm),and the mean number of lymph nodes harvested was 18.7(range, 8-27).At a mean follow-up of 20.6 mo(range,10-37 mo),there were no functional disorders associated with the transvaginal and transanal specimen extraction. CONCLUSION:Transvaginal or transanal extraction in L-TME is a safe and effective procedure.Natural orifice specimen extraction can avoid the abdominal wall incision and its potential complications.
文摘AIM: To investigate the prevalence and implications of unusual histopathological findings in appendectomy specimens from patients with suspected acute appendicitis. METHODS: The demographic and histopathological data of 1621 patients (≥ 16 years-old) who underwent appendectomy to treat an initial diagnosis of acute appendicitis between January 1999 and November 2011 were retrospectively assessed. Microscopic findings were used to classify the patients under six categories: appendix vermiformis, phlegmonous appendicitis, gan- grenous appendicitis, perforated appendicitis, supurative appendicitis, and unusual histopathologic findings. The demographic and clinicopathologic characteristics of patients with unusual histopathologic findings were evaluated in detail, and re-analysis of archived resected appendix specimens was carried out. RESULTS: A total of 912 males and 709 females, from16 to 94 years old, were included in the study and comprised 789 cases of suppurative appendicitis, 370 cases of appendix vermiformis, 243 cases of perforated gangrenous appendicitis, 53 cases of flegmaneous appendicitis, 32 cases of gangrenous appendicitis, and 134 (8.3%) cases of unusual histopathological findings. The unusual histopathological findings included fibrous obliteration (n = 62), enterobius vermicularis (n = 31), eosinophilic infiltration (n = 10), mucinous cystadenoma (n = 8), carcinoid tumor (n = 6), granulomatous inflammation (n = 5), adenocarcinoma (n = 4; one of them mucinous), and mucocele (n = 3), adenomatous polyp (n = 1), taenia sup (n = 1), ascaris lumbricoides (n = 1), appendiceal diverticula (n = 1), and B cell non-hodgkin lymphoma (n = 1). None of the 11 patients with subsequent diagnosis of tumor were suspected of cancer prior to the appendectomy. CONCLUSION: Even when the macroscopic appearance of appendectomy specimens is normal, histopathological assessment will allow early diagnosis of many unusual diseases.
基金Supported by National Natural Science Foundation of China,No.81500430 and No.U1304802(to Lin XH)Basic and Frontier Technology Research Program of Henan Province,No.162300410101(to Hu JH)+1 种基金Wu Jieping Medical Foundation of Clinical Research Special Fund,No.320.2710.1836(to Hu JH)The Henan Science and Technology Planning Project,No.182102310544(to Lin XH)
文摘BACKGROUND This case-control study compared the short-term clinical efficacy of natural orifice specimen extraction surgery(NOSES) using a prolapsing technique and the conventional laparoscopic-assisted approach for low rectal cancer.AIM To further explore the application value of the transanal placement of the anvil and to evaluate the short-term efficacy of NOSES for resecting specimens of low rectal cancer, as well as to provide a theoretical basis for its extensive clinical application.METHODS From June 2015 to June 2018, 108 consecutive laparoscopic-assisted low rectal cancer resections were performed at our center. Among them, 26 specimens were resected transanally using a prolapsing technique(NOSES), and 82 specimens were resected through a conventional abdominal wall small incision(LAP). A propensity score matching method was used to select 26 pairs of matched patients, and their perioperative data were analyzed.RESULTS The baseline data were comparable between the two matched groups. All 52 patients underwent the surgery successfully. The operative time, blood loss,number of harvested lymph nodes, postoperative complication rate,circumferential margin involvement, postoperative follow-up data, and postoperative anal function were not statistically significant. The NOSES group had shorter time to gastrointestinal function recovery(2.6 ± 1.0 d vs 3.4 ± 0.9 d, P= 0.006), shorter postoperative hospital stay(7.1 ± 1.7 d vs 8.3 ± 1.1 d, P = 0.003),lower pain score(day 1: 2.7 ± 1.8 vs 4.6 ± 1.9, day 3: 2.0 ± 1.1 vs 4.1 ± 1.2, day 5: 1.7± 0.9 vs 3.3 ± 1.0, P < 0.001), a lower rate of additional analgesic use(11.5% vs61.5%, P = 0.001), and a higher satisfaction rate in terms of the aesthetic appearance of the abdominal wall after surgery(100% vs 23.1%, P < 0.001).CONCLUSION NOSES for low rectal cancer can achieve satisfactory short-term efficacy and has advantages in reducing postoperative pain, shortening the length of postoperative hospital stay, and improving patients' satisfaction in terms of a more aesthetic appearance of the abdominal wall.
文摘Over the last 20 years, laparoscopic colorectal surgery has shown equal efficacy for benign and malignant colorectal diseases when compared to open surgery. However, a laparoscopic approach reduces postoperative morbidity and shortens hospital stay. In the quest to optimize outcomes after laparoscopic colorectal surgery, reduction of access trauma could be a way to improve recovery. To date, one method to reduce access trauma is natural orifice specimen extraction(NOSE). NOSE aims to reduce access trauma in laparoscopic colorectal surgery. The specimen is delivered via a natural orifice and the anastomosis is created intracorporeally. Different methods are used to extract the specimen and to create a bowel anastomosis. Currently, specimens are delivered transcolonically, transrectally, transanally, or transvaginally. Each of these NOSEprocedures raises specific issues with regard to operative technique and application. The presumed benefits of NOSE-procedures are less pain, lower analgesia requirements, faster recovery, shorter hospital stay, better cosmetic results, and lower incisional hernia rates. Avoidance of extraction site laparotomy is the most important characteristic of NOSE. Concerns associated with the NOSE-technique include bacterial contamination of the peritoneal cavity, inflammatory response, and postoperative outcomes, including postoperative pain and the functional and oncologic outcomes. These issues need to be studied in prospective randomized controlled trials. The aim of this systematic review is to describe the role of NOSE in minimally invasive colorectal surgery.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.51771207 and 51571199)
文摘This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effects sensitive to microstructures including the specimen thickness, grain size and a ratio between them are highlighted to summarize some general rules for size effects. Then, ongoing research progress and new challenges in evaluating the fatigue performance of additive manufactured parts controlled by location-specific defects, microstructure heterogeneities as well as mechanical anisotropy using miniature specimen testing technique are discussed and addressed. Finally, a potential roadmap to establish a data-driven evaluation platform based on a large number of miniature specimen-based experiment data,theoretical computations and the ’big data’ analysis with machine learning is proposed. It is expected that this overview would provide a novel strategy for the realistic evaluation and fast qualification of fatigue properties of additive manufactured parts we have been facing to.
文摘AIM: To investigate how complete laparoscopic anterior resection with natural orifice specimen extraction (NOSE), as a novel minimally invasive surgery, compares to conventional laparoscopic surgery.
基金supported by the China Mega-Project for Infectious Disease(2016ZX10004-101,2016ZX10004-215)Beijing Municipal Science&Technology Commission Project(D151100002115003)Guangzhou Municipal Science&Technology Commission Project(2015B2150820)
文摘Objective To provide a feasible and cost-effective next-generation sequencing （NGS） method for accurate identification of viral pathogens in clinical specimens, because enormous limitations impede the clinical use of common NGS, such as high cost, complicated procedures, tremendous data analysis, and high background noise in clinical samples. Methods Viruses from cell culture materials or clinical specimens were identified following an improved NGS procedure： reduction of background noise by sample preprocessing, viral enrichment by barcoded oligonucleotide （random hexamer or non-ribosomal hexanucleotide） primer-based amplification, fragmentation-free library construction and sequencing of one-tube mixtures, as well as rapid data analysis using an in-house pipeline. Results NGS data demonstrated that both barcoded primer sets were useful to simultaneously capture multiple viral pathogens in cell culture materials or clinical specimens and verified that hexanucleotide primers captured as many viral sequences as hexamers did. Moreover, direct testing of clinical specimens using this improved hexanucleotide primer-based NGS approach provided further detailed genotypes of enteroviruses causing hand, foot, and mouth disease （HFMD） and identified other potential viruses or differentiated misdiagnosis events. Conclusion The improved barcoded oligonucleotide primer-based NGS approach is simplified, time saving, cost effective, and appropriate for direct identification of viral pathogens in clinical practice.
