BACKGROUND Cold snare polypectomy(CSP)is comparatively safe and effective for removing polyps less than 10 mm in size with lower rates of postpolypectomy syndrome and delayed postpolypectomy bleeding compared with hot...BACKGROUND Cold snare polypectomy(CSP)is comparatively safe and effective for removing polyps less than 10 mm in size with lower rates of postpolypectomy syndrome and delayed postpolypectomy bleeding compared with hot snare polypectomy(HSP).Recently,CSP is also expanded for removing polyps larger than 10 mm in size.AIM To compare the efficiency and safety of CSP and HSP in the management of 10-19 mm non-pedunculated colorectal polyps.METHODS A total of 1686 inpatients with at least one 10-19 mm non-pedunculated colorectal polyp,who underwent CSP(study group,n=843)or HSP(control group,n=843)at our Digestive Endoscopy Center between February 2020 and February 2024 were enrolled.The outcome measures including complete resection rate,intraoperative bleeding rate,and healthcare expenses such as procedure time and treatment cost were compared between the CSP vs HSP groups.RESULTS No statistically significant intergroup difference was observed in histological complete resection rates(P>0.05).Polyp resection time in the study group(76.5±23.6 seconds)was notably shorter than that in the control group(91.24±32.06 seconds;P<0.05).The immediate intraoperative bleeding rate was significantly higher in the study group than in the control group(12.7%vs 4.9%,P<0.05).No instances of delayed bleeding or perforation were documented in either group.Hospitalization duration was significantly reduced in the study group(2.42±0.61 days)compared to the control group(3.21±1.02 days;P<0.05).CONCLUSION For 10-19 mm non-pedunculated colorectal polyps,CSP demonstrates operational efficiency advantages over HSP in terms of procedure time,treatment cost,and length of hospital stay.Both techniques demonstrate robust safety profiles;however,CSP is associated with a higher intraoperative bleeding rate.Clinical decision-making should incorporate individualized assessment of these factors.展开更多
Ulcerative colitis(UC)is a chronic and non-specific inflammatory bowel disease(IBD).Huanglian Ganjiang decoction(HGD),derived from ancient book Beiji Qianjin Yao Fang,has demonstrated efficacy in treating UC patients ...Ulcerative colitis(UC)is a chronic and non-specific inflammatory bowel disease(IBD).Huanglian Ganjiang decoction(HGD),derived from ancient book Beiji Qianjin Yao Fang,has demonstrated efficacy in treating UC patients traditionally.Previous research established that the compatibility of cold herb Coptidis Rhizoma+Phellodendri Chinensis Cortex(CP)and hot herb Angelicae Sinensis Radix+Zingiberis Rhizoma(AZ)in HGD synergistically improved colitis mice.This study investigated the compatibility mechanisms through which CP and AZ regulated inflammatory balance in colitis mice.The experimental colitis model was established by administering 3%dextran sulphate sodium(DSS)to mice for 7 days,followed by CP,AZ and CPAZ treatment for an additional 7 days.M1/M2 macrophage polarization levels,glucose metabolites levels and pyruvate dehydrogenase kinase 4(PDK4)expression were analyzed using flow cytometry,Western blot,immunofluorescence and targeted glucose metabolomics.The findings indicated that CP inhibited M1 macrophage polarization,decreased inflammatory metabolites associated with tricarboxylic acid(TCA)cycle,and suppressed PDK4 expression and pyruvate dehydrogenase(PDH)(Ser-293)phosphorylation level.AZ enhanced M2 macrophage polarization,increased lactate axis metabolite lactate levels,and upregulated PDK4 expression and PDH(Ser-293)phosphorylation level.TCA cycle blocker AG-221 and adeno-associated virus(AAV)-PDK4 partially negated CP’s inhibition of M1 macrophage polarization.Lactate axis antagonist oxamate and PDK4 inhibitor dichloroacetate(DCA)partially reduced AZ’s activation of M2 macrophage polarization.In conclusion,the compatibility of CP and AZ synergistically alleviated colitis in mice through M1/M2 macrophage polarization balance via PDK4-mediated glucose metabolism reprogramming.Specifically,CP reduced M1 macrophage polarization by restoration of TCA cycle via PDK4 inhibition,while AZ increased M2 macrophage polarization through activation of PDK4/lactate axis.展开更多
The Ti-36Nb-2Ta-3Zr-0.350 （mass fraction, %） （TNTZO） alloy was produced by cold isostatic pressing and sintering from elemental powders, followed by hot and cold deformation. The effects of deformation process on ...The Ti-36Nb-2Ta-3Zr-0.350 （mass fraction, %） （TNTZO） alloy was produced by cold isostatic pressing and sintering from elemental powders, followed by hot and cold deformation. The effects of deformation process on microstructures and mechanical properties were investigated using the SEM, TEM, OM and the universal material testing machine. Results show that the alloy can be easily hot forged and cold swaged due to the fine-grained microstructure. Only after cold swaging by 85%, the alloy shows the typical ＂marble-like＂ structure. And thecold deformation is accompanied by stress-induced a＂ phase transformations. Moreover, both the strength and the ductility of the alloy are significantly improved by hot and cold working.展开更多
In order to improve the control ability of synthetic jets in compressible boundary layer,a novel control method based on dual synthetic cold/hot jets coupled control of velocity profile and temperature profile was pro...In order to improve the control ability of synthetic jets in compressible boundary layer,a novel control method based on dual synthetic cold/hot jets coupled control of velocity profile and temperature profile was proposed.As fundamental investigations on the effects of synthetic jet temperature on the jet behavior and flow field characteristics were essentially necessary,preliminary numerical simulations were conducted to study the influence of temperature(200 K and 400 K)on the flow field characteristics of synthetic jets using Large Eddy Simulations(LES)model.Time-averaged flow fields showed that different temperatures led to variable behavior of two strands of jets.For dual synthetic cold jets,a potential-core arose apparently with its height ranging from 0.01 to 0.03 m,while for dual synthetic hot jets,two strands of jets emerged downstream.The modal decomposition of instantaneous flow fields had been done using both Proper Orthogonal Decomposition(POD)and Dynamic Mode Decomposition(DMD).Various modes showed different characteristics of the flow fields.As the POD method focuses on the energy of flow while the DMD method focuses on the frequency,the first two modes had many similarities,but the third and fourth modes demonstrated completely different vortex structures.The current researches play a role of preliminary investigations for further and comprehensive exploration of novel flow control measures in global velocity field.展开更多
It recently becomes an important and urgent mission for modern scientific research to identify and explain the theory of traditional Chinese medicine(TCM), which has been utilized in China for more than four millennia...It recently becomes an important and urgent mission for modern scientific research to identify and explain the theory of traditional Chinese medicine(TCM), which has been utilized in China for more than four millennia. Since few works have been contributed to understanding the TCM theory, the mechanism of actions of drugs with cold/hot properties remains unclear. In the present study, six kinds of typical herbs with cold or hot properties were orally administered into mice, and serum and liver samples were analyzed using an untargeted nuclear magnetic resonance(NMR) based metabolomics approach coupled with similarity analysis. This approach was performed to identify and quantify changes in metabolic pathways to elucidate drug actions on the treated mice. Our results showed that those drugs with same property exerted similar effects on the metabolic alterations in mouse serum and liver samples, while drugs with different property showed different effects. The effects of herbal medicines with cold/hot properties were exerted by regulating the pathways linked to glycometabolism, lipid metabolism, amino acids metabolism and other metabolic pathways. The results elucidated the differences and similarities of drugs with cold/hot properties, providing useful information on the explanation of medicinal properties of these TCMs.展开更多
AIMTo compare the efficacy and safety of cold snare polypectomy (CSP) and hot forceps biopsy (HFB) for diminutive colorectal polyps.METHODSThis prospective, randomized single-center clinical trial included consecutive...AIMTo compare the efficacy and safety of cold snare polypectomy (CSP) and hot forceps biopsy (HFB) for diminutive colorectal polyps.METHODSThis prospective, randomized single-center clinical trial included consecutive patients ≥ 20 years of age with diminutive colorectal polyps 3-5 mm from December 2014 to October 2015. The primary outcome measures were en-bloc resection (endoscopic evaluation) and complete resection rates (pathological evaluation). The secondary outcome measures were the immediate bleeding or immediate perforation rate after polypectomy, delayed bleeding or delayed perforation rate after polypectomy, use of clipping for bleeding or perforation, and polyp retrieval rate. Prophylactic clipping after polyp removal wasn’t routinely performed.RESULTSTwo hundred eight patients were randomized into the CSP (102), HFB (106) and 283 polyps were evaluated (CSP: 148, HFB: 135). The en-bloc resection rate was significantly higher with CSP than with HFB [99.3% (147/148) vs 80.0% (108/135), P < 0.0001]. The complete resection rate was significantly higher with CSP than with HFB [80.4% (119/148) vs 47.4% (64/135), P < 0.0001]. The immediate bleeding rate was similar between the groups [8.6% (13/148) vs 8.1% (11/135), P = 1.000], and endoscopic hemostasis with hemoclips was successful in all cases. No cases of perforation or delayed bleeding occurred. The rate of severe tissue injury to the pathological specimen was higher HFB than CSP [52.6% (71/135) vs 1.3% (2/148), P < 0.0001]. Polyp retrieval failure was encountered CSP (7), HFB (2).CONCLUSIONCSP is more effective than HFB for resecting diminutive polyps. Further long-term follow-up study is required.展开更多
AIM: To compare previously reported randomized controlled studies (RCTs) of cold and hot polypectomy, we systematically reviewed and clarify the utility of cold polypectomy over hot with respect to efficacy and advers...AIM: To compare previously reported randomized controlled studies (RCTs) of cold and hot polypectomy, we systematically reviewed and clarify the utility of cold polypectomy over hot with respect to efficacy and adverse events.METHODS: A meta-analysis was conducted to evaluate the predominance of cold and hot polypectomy for removing colon polyps. Published articles and abstracts from worldwide conferences were searched using the keywords “cold polypectomy”. RCTs that compared either or both the effects or adverse events of cold polypectomy with those of hot polypectomy were collected. The patients’ demographics, endoscopic procedures, No. of examined lesions, lesion size, macroscopic and histologic findings, rates of incomplete resection, bleeding amount, perforation, and length of procedure were extracted from each study. A forest plot analysis was used to verify the relative strength of the effects and adverse events of each procedure. A funnel plot was generated to assess the possibility of publication bias.RESULTS: Ultimately, six RCTs were selected. No significant differences were noted in the average lesion size (less than 10 mm) between the cold and hot polypectomy groups in each study. Further, the rates of complete resection and adverse events, including delayed bleeding, did not differ markedly between cold and hot polypectomy. The average procedural time in the cold polypectomy group was significantly shorter than in the hot polypectomy group.CONCLUSION: Cold polypectomy is a time-saving procedure for removing small polyps with markedly similar curability and safety to hot polypectomy.展开更多
Tension-tension fatigue properties of hot rolled and cold rolled strips with same contents and sizes were measured by using group test method at room temperature in air. The results showed that the fatigue properties ...Tension-tension fatigue properties of hot rolled and cold rolled strips with same contents and sizes were measured by using group test method at room temperature in air. The results showed that the fatigue properties of the hot rolled strips were obviously higher than those of the cold rolled strips. The hot rolled strips with similar or higher tensile strength exhibited superior fatigue property over the cold rolled strips. Fracture morphologies observed using scanning electronic microscope （SEM） showed that the hot rolled strips exhibited larger fracture areas, indicating a slightly lower plasticity, and more even fracture microstructure and stable properties. It is feasible and reliable to replace cold rolled strips with hot rolled strips.展开更多
This is a comment on a meta-analysis of published studies comparing cold vs hot polypectomy. We believe that the conclusion of this meta-analysis that "cold polypectomy is a time-saving procedure for removing sma...This is a comment on a meta-analysis of published studies comparing cold vs hot polypectomy. We believe that the conclusion of this meta-analysis that "cold polypectomy is a time-saving procedure for removing small polyps with markedly similar curability and safety to hot polypectomy" needs more rigorous evidence.展开更多
Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is...Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.展开更多
As a key component of injection molding,multi-cavity hot runner(MCHR)system faces the crucial problem of polymer melt filling imbalance among the cavities.The thermal imbalance in the system has been considered as the...As a key component of injection molding,multi-cavity hot runner(MCHR)system faces the crucial problem of polymer melt filling imbalance among the cavities.The thermal imbalance in the system has been considered as the leading cause.Hence,the solution may rest with the synchronization of those heating processes in MCHR system.This paper proposes a’Master-Slave’generalized predictive synchronization control(MS-GPSC)method with’Mr.Slowest’strategy for preheating stage of MCHR system.The core of the proposed method is choosing the heating process with slowest dynamics as the’Master’to track the setpoint,while the other heating processes are treated as‘Slaves’tracking the output of’Master’.This proposed method is shown to have the good ability of temperature synchronization.The corresponding analysis is conducted on parameters tuning and stability,simulations and experiments show the strategy is effective.展开更多
Among the bottlenecks that hinder the improvement of the production efficiency of hot stamping are high strength and difficulty in edge cutting and hole punching.Starting from the preparation of hot stamping multiphas...Among the bottlenecks that hinder the improvement of the production efficiency of hot stamping are high strength and difficulty in edge cutting and hole punching.Starting from the preparation of hot stamping multiphase microstructure materials,this paper developed a plate quenching die system with controllable surface temperature and prepared four types of hot stamping plates with different martensite volume fractions.Then,straight edge cold cutting experiments were performed to study the influence of cutting clearance and cutting force on fracture quality.The results show that the bright zone is the largest when the cutting clearance is 0.14 mm,and the cutting experience coefficient of the hot stamping sheet with each martensite volume fraction is obtained when the cutting clearance is 0.14 mm.The research results of this paper were applied to the production of hot stamping parts.展开更多
Tibetan medicinal plants have been used for more than 2 000 years. In order to find their differences in antioxidant activity, total phenolics and total flavonoids between "hot-nature" and "cold-nature&...Tibetan medicinal plants have been used for more than 2 000 years. In order to find their differences in antioxidant activity, total phenolics and total flavonoids between "hot-nature" and "cold-nature" herbs, we investigated the antioxidant activities of 40 Tibetan herbs from Qinghai plateau, with 20 herbs in cold-nature and 20 herbs in hot-nature. Antioxidant capacities were evaluated by the following methods: scavenging ABTS?+(2, 2′azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid), scavenging O2?-, and Ferric-reducing antioxidant power(FRAP). The effects on inhibition of mitochondrion lipid peroxidation were determined by measuring the formation of TBARS(Thiobarbituric acid reactive substrates). Total phenolics and flavonoids were estimated by Folin-Ciocalteu and Na NO2-Al(NO3)3-Na OH colorimetric methods. Interestingly, the cold-nature herbs displayed higher antioxidant activities than the hot-nature ones, corresponding to nearly three-fold higher total phenolic contents in the cold-nature herbs. Moreover, the antioxidant activities correlated linearly with the levels of total phenolics for both cold-nature and hot-nature herbs, but only with the levels of total flavonoids for the hot-nature herbs. The results suggested that the phenolic compounds, but not the flavonoids, play the major role in antioxidant capacities of the cold-nature herbs. These findings could shed new lights on the study the theory of Tibetan medicine.展开更多
In this study,the scale and internal oxidation of hot-rolled ultra-high strength steel sheets were characterized.It was found that both the formation of the scale and the internal oxidation of Si and Mn depended on th...In this study,the scale and internal oxidation of hot-rolled ultra-high strength steel sheets were characterized.It was found that both the formation of the scale and the internal oxidation of Si and Mn depended on the coiling temperature and position of the steel sample on the strip coil.At a relatively high coiling temperature,a large amount of internal oxidation was observed on the samples cut from the middle of the coil.The depth of the internal oxidation zone exceeded 10 μm and a thin iron layer covering the scale was observed in some cases.Pickling and cold-rolling experiments were conducted on selected samples.Scale pickling was found to be greatly delayed by the formation of an iron layer,which frequently resulted in under-pickled defects.In addition,pickling of the entire internal oxidation zone was difficult,except at the grain boundaries,where the degree of internal Si and Mn oxidation was enriched.The surface of the cold-rolled steel sheet was ruined by the remaining oxidation zone in the subsurface of the pickled steel.The internal oxidation of hot-rolled ultra-high strength steel must be precisely controlled to improve the subsequent surface quality of cold-rolled steel.展开更多
In this study, we propose a new temperature compensation control strategy for a multi-cavity hot runner injection molding system, At first, the melt filling time of each cavity can be measured by installing temperatur...In this study, we propose a new temperature compensation control strategy for a multi-cavity hot runner injection molding system, At first, the melt filling time of each cavity can be measured by installing temperature sensors on the position around end filling area, and filling time difference between the various cavities can be calculated. Then the melt temperature of each hot nozzle can be adjusted automatically by a control strategy established based on the Fuzzy Theory and a program compiled with LABVIEW software. Temperature changes the melt mobility, so the adjustment of temperature can equalize the filling time of the melt in each cavity, which can reduced the mass deviation between each cavity and make product properties of each cavity consistent. The conclusion of the experiment is as follows： For this contact lens box of a four-cavity Hot Runner mold, by applying hot runner temperature compensation control system, time difference can be reduced from 0.05 s to 0.01 s at each cavity, and the mass Standard deviation of the four cavity can be improved from 0.006 to 0.002. The ratio of imbalance can be reduced from 20% to 4%. Hence, the hot runner temperature compensation control system has significant feasibility and high potential in improving melt flow balance of multi-cavity molding application.展开更多
Starting from the research on and collection of the damaging factors andindex of the cold and hot damages to citrus, this peper systematically studies the apparent properties in temporal and spatial distribution, diff...Starting from the research on and collection of the damaging factors andindex of the cold and hot damages to citrus, this peper systematically studies the apparent properties in temporal and spatial distribution, differences, relationship of the twokinds of disasters and their impact on citrus production in the Three Gorges area inHubei. It also reveals the important faCt that it is warmer in winter and hotter in springsince the 1980s, which is the cause of departing to two poles of the cold and hot damages, and discusses the alleviating effect to the disasters by the Three Gorges Project.Finally some countermeasures are proposed.展开更多
In an injection moulding process, the mould cooling s ystem is very important as an efficient and uniform cooling effect can improve b oth the productivity and part quality. Due to the complexity of the process, muc h...In an injection moulding process, the mould cooling s ystem is very important as an efficient and uniform cooling effect can improve b oth the productivity and part quality. Due to the complexity of the process, muc h research on the mould cooling analysis and cooling design optimization has bee n focused on the core and the cavity, excluding other systems of injection mould s. However, the runner system introduces a considerable amount of heat into the mould. In recent years, more and more hot runner systems are being applied in th e moulding industry to save material and decrease losses of injection pressure. This raises the need to include the hot runner system in the cooling analysis. I n this paper, a photo frame part was studied. The mould was built with a hot run ner system. Two thermal sensors were installed: one measures the temperature of lateral surface of hot runner nozzle; the other measures the plastic temperature from the core side. A pressure sensor was also installed to measure the pressur e of the core impression. Cooling analysis was performed using ABAQUS, ananalysi s software based on the Finite Element Method (FEM). The assembly including core , cavity and plastic part was modeled. Heat conduction from hot runner to cavity and from polymer melt to the mould and force convection on the cooling channel surfaces were studied. The natural convection between the ambient air and the ex terior mould surface was ignored. The simulations were adjusted with the experim ental results to find out the heat input from hot runner and its influence on mo uld cooling. Finally, the optimal cooling design and optimal injection condition were obtained.展开更多
In an injection moulding process, the parallelism b et ween the tie bars of the injection moulding machine is very important as it will affect the mould closing and clamping system. In recent years, more and more ho t...In an injection moulding process, the parallelism b et ween the tie bars of the injection moulding machine is very important as it will affect the mould closing and clamping system. In recent years, more and more ho t runner systems are being applied in the moulding industry to save material and decrease the losses of injection pressure. Heat transfer from hot runner system from the fixed half which is secured in the fix machine platen could transmit s o much heat that it may cause high temperature differential between the machine fix platen and moving platen. This will cause the tie bar to become unparallel. Part quality will be compromised and the wear of the tie bar will be excessive. Overhaul of the tie bar may be necessary after a short period of time which is c ostly. This raises the need to analyze the heat transfer from the hot runner sys tem to the machine fix platen and the methods of isolating or minimizing the hea t transfer. In this case study, a photo lens article mould was used. The mould w as built with a direct hot runner nozzle system. Heat conduction from hot runner and machine screw to machine fix platen were studied based on either using high temperature heat insulating plate put in placed between the mould and the mould ing machine fix platen or drill cooling channels in the front mould clamping pla te. The high temperature insulator is very costly as it is made out of glass re inforced polymer composite material. Experimental results were obtained and anal yzed to find the best method to minimize the unwanted heat transfer using the ch eapest and most effective method.展开更多
Hot crack is one of common defects in castings, which often results in failure of castings. This work studies the formation of hot crack during cold crucible continuous casting by means of experiments and theoretical ...Hot crack is one of common defects in castings, which often results in failure of castings. This work studies the formation of hot crack during cold crucible continuous casting by means of experiments and theoretical analysis. The results show that hot crack occurs on the surface and in the circumference of ingots, where the solidified shell and the solidification front meet each other. The tendency of hot cracking decreases with the increase of withdrawal velocities in some extent. The hot crack is caused mainly by the friction force between the shell and the crucible inner wall, and it takes place when the stress resulting from friction exceeds the tensile strength of the shell. The factors of μ_m, η_t, η_s and η_m, affecting hot cracks are analyzed and verified. In order to decrease the tendency of hot cracks, technical parameters should be optimized by decreasing μ_m, η_t, η_s and η_m.展开更多
A new processing method for producing hot dip galvanized steel is designed and tested, in which pickling is skipped. Hot-rolled low carbon steel sheets are roiled with oxide scale in an experimental mill at room tempe...A new processing method for producing hot dip galvanized steel is designed and tested, in which pickling is skipped. Hot-rolled low carbon steel sheets are roiled with oxide scale in an experimental mill at room temperature, prior to annealing under a 20% hydrogen reducing atmosphere and galvanizing on a hot-dip galvanizing simulator. Micro-cracks formed in the oxide scale during cold rolling roughen the steel surface and enlarge the specific surface. Through-thickness cracks provide transport channels for hydrogen, and hence the reduction of oxide scale is en- hanced. When the sheet is dipped in the zinc bath, cracks are submerged by liquated zinc and the defects are not dis- tinct after hot-dip galvanizing. The overlay coating occludes with rough surface of the sheet, whereby a superior coat- ing adherence is realized.展开更多
文摘BACKGROUND Cold snare polypectomy(CSP)is comparatively safe and effective for removing polyps less than 10 mm in size with lower rates of postpolypectomy syndrome and delayed postpolypectomy bleeding compared with hot snare polypectomy(HSP).Recently,CSP is also expanded for removing polyps larger than 10 mm in size.AIM To compare the efficiency and safety of CSP and HSP in the management of 10-19 mm non-pedunculated colorectal polyps.METHODS A total of 1686 inpatients with at least one 10-19 mm non-pedunculated colorectal polyp,who underwent CSP(study group,n=843)or HSP(control group,n=843)at our Digestive Endoscopy Center between February 2020 and February 2024 were enrolled.The outcome measures including complete resection rate,intraoperative bleeding rate,and healthcare expenses such as procedure time and treatment cost were compared between the CSP vs HSP groups.RESULTS No statistically significant intergroup difference was observed in histological complete resection rates(P>0.05).Polyp resection time in the study group(76.5±23.6 seconds)was notably shorter than that in the control group(91.24±32.06 seconds;P<0.05).The immediate intraoperative bleeding rate was significantly higher in the study group than in the control group(12.7%vs 4.9%,P<0.05).No instances of delayed bleeding or perforation were documented in either group.Hospitalization duration was significantly reduced in the study group(2.42±0.61 days)compared to the control group(3.21±1.02 days;P<0.05).CONCLUSION For 10-19 mm non-pedunculated colorectal polyps,CSP demonstrates operational efficiency advantages over HSP in terms of procedure time,treatment cost,and length of hospital stay.Both techniques demonstrate robust safety profiles;however,CSP is associated with a higher intraoperative bleeding rate.Clinical decision-making should incorporate individualized assessment of these factors.
基金supported by the National Natural Science Foundation of China(Nos.82374325 and 82074322)GDAS'ProjectofScience and Technology Development(No.2022GDASZH-2022010110).
文摘Ulcerative colitis(UC)is a chronic and non-specific inflammatory bowel disease(IBD).Huanglian Ganjiang decoction(HGD),derived from ancient book Beiji Qianjin Yao Fang,has demonstrated efficacy in treating UC patients traditionally.Previous research established that the compatibility of cold herb Coptidis Rhizoma+Phellodendri Chinensis Cortex(CP)and hot herb Angelicae Sinensis Radix+Zingiberis Rhizoma(AZ)in HGD synergistically improved colitis mice.This study investigated the compatibility mechanisms through which CP and AZ regulated inflammatory balance in colitis mice.The experimental colitis model was established by administering 3%dextran sulphate sodium(DSS)to mice for 7 days,followed by CP,AZ and CPAZ treatment for an additional 7 days.M1/M2 macrophage polarization levels,glucose metabolites levels and pyruvate dehydrogenase kinase 4(PDK4)expression were analyzed using flow cytometry,Western blot,immunofluorescence and targeted glucose metabolomics.The findings indicated that CP inhibited M1 macrophage polarization,decreased inflammatory metabolites associated with tricarboxylic acid(TCA)cycle,and suppressed PDK4 expression and pyruvate dehydrogenase(PDH)(Ser-293)phosphorylation level.AZ enhanced M2 macrophage polarization,increased lactate axis metabolite lactate levels,and upregulated PDK4 expression and PDH(Ser-293)phosphorylation level.TCA cycle blocker AG-221 and adeno-associated virus(AAV)-PDK4 partially negated CP’s inhibition of M1 macrophage polarization.Lactate axis antagonist oxamate and PDK4 inhibitor dichloroacetate(DCA)partially reduced AZ’s activation of M2 macrophage polarization.In conclusion,the compatibility of CP and AZ synergistically alleviated colitis in mice through M1/M2 macrophage polarization balance via PDK4-mediated glucose metabolism reprogramming.Specifically,CP reduced M1 macrophage polarization by restoration of TCA cycle via PDK4 inhibition,while AZ increased M2 macrophage polarization through activation of PDK4/lactate axis.
基金Project(2014CB644002)supported by the National Key Fundamental Research and Development Project of ChinaProject(51301203)supported by the National Natural Science Foundation of China+1 种基金Project(2015CX004)supported by the Innovation-driven Plan in Central South University,Chinasupported by the Outstanding Graduate Project of Advanced Non-ferrous Metal Structural Materials and Manufacturing Collaborative Innovation Center,China
文摘The Ti-36Nb-2Ta-3Zr-0.350 （mass fraction, %） （TNTZO） alloy was produced by cold isostatic pressing and sintering from elemental powders, followed by hot and cold deformation. The effects of deformation process on microstructures and mechanical properties were investigated using the SEM, TEM, OM and the universal material testing machine. Results show that the alloy can be easily hot forged and cold swaged due to the fine-grained microstructure. Only after cold swaging by 85%, the alloy shows the typical ＂marble-like＂ structure. And thecold deformation is accompanied by stress-induced a＂ phase transformations. Moreover, both the strength and the ductility of the alloy are significantly improved by hot and cold working.
基金supported by the National Natural Science Foundation of China(Nos.11602299,11502295,11572349,11872374 and 51809271).
文摘In order to improve the control ability of synthetic jets in compressible boundary layer,a novel control method based on dual synthetic cold/hot jets coupled control of velocity profile and temperature profile was proposed.As fundamental investigations on the effects of synthetic jet temperature on the jet behavior and flow field characteristics were essentially necessary,preliminary numerical simulations were conducted to study the influence of temperature(200 K and 400 K)on the flow field characteristics of synthetic jets using Large Eddy Simulations(LES)model.Time-averaged flow fields showed that different temperatures led to variable behavior of two strands of jets.For dual synthetic cold jets,a potential-core arose apparently with its height ranging from 0.01 to 0.03 m,while for dual synthetic hot jets,two strands of jets emerged downstream.The modal decomposition of instantaneous flow fields had been done using both Proper Orthogonal Decomposition(POD)and Dynamic Mode Decomposition(DMD).Various modes showed different characteristics of the flow fields.As the POD method focuses on the energy of flow while the DMD method focuses on the frequency,the first two modes had many similarities,but the third and fourth modes demonstrated completely different vortex structures.The current researches play a role of preliminary investigations for further and comprehensive exploration of novel flow control measures in global velocity field.
基金supported by the Science and Technology Innovation Team of Shanxi Province(No.2013131015)Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi(OIT)
文摘It recently becomes an important and urgent mission for modern scientific research to identify and explain the theory of traditional Chinese medicine(TCM), which has been utilized in China for more than four millennia. Since few works have been contributed to understanding the TCM theory, the mechanism of actions of drugs with cold/hot properties remains unclear. In the present study, six kinds of typical herbs with cold or hot properties were orally administered into mice, and serum and liver samples were analyzed using an untargeted nuclear magnetic resonance(NMR) based metabolomics approach coupled with similarity analysis. This approach was performed to identify and quantify changes in metabolic pathways to elucidate drug actions on the treated mice. Our results showed that those drugs with same property exerted similar effects on the metabolic alterations in mouse serum and liver samples, while drugs with different property showed different effects. The effects of herbal medicines with cold/hot properties were exerted by regulating the pathways linked to glycometabolism, lipid metabolism, amino acids metabolism and other metabolic pathways. The results elucidated the differences and similarities of drugs with cold/hot properties, providing useful information on the explanation of medicinal properties of these TCMs.
文摘AIMTo compare the efficacy and safety of cold snare polypectomy (CSP) and hot forceps biopsy (HFB) for diminutive colorectal polyps.METHODSThis prospective, randomized single-center clinical trial included consecutive patients ≥ 20 years of age with diminutive colorectal polyps 3-5 mm from December 2014 to October 2015. The primary outcome measures were en-bloc resection (endoscopic evaluation) and complete resection rates (pathological evaluation). The secondary outcome measures were the immediate bleeding or immediate perforation rate after polypectomy, delayed bleeding or delayed perforation rate after polypectomy, use of clipping for bleeding or perforation, and polyp retrieval rate. Prophylactic clipping after polyp removal wasn’t routinely performed.RESULTSTwo hundred eight patients were randomized into the CSP (102), HFB (106) and 283 polyps were evaluated (CSP: 148, HFB: 135). The en-bloc resection rate was significantly higher with CSP than with HFB [99.3% (147/148) vs 80.0% (108/135), P < 0.0001]. The complete resection rate was significantly higher with CSP than with HFB [80.4% (119/148) vs 47.4% (64/135), P < 0.0001]. The immediate bleeding rate was similar between the groups [8.6% (13/148) vs 8.1% (11/135), P = 1.000], and endoscopic hemostasis with hemoclips was successful in all cases. No cases of perforation or delayed bleeding occurred. The rate of severe tissue injury to the pathological specimen was higher HFB than CSP [52.6% (71/135) vs 1.3% (2/148), P < 0.0001]. Polyp retrieval failure was encountered CSP (7), HFB (2).CONCLUSIONCSP is more effective than HFB for resecting diminutive polyps. Further long-term follow-up study is required.
文摘AIM: To compare previously reported randomized controlled studies (RCTs) of cold and hot polypectomy, we systematically reviewed and clarify the utility of cold polypectomy over hot with respect to efficacy and adverse events.METHODS: A meta-analysis was conducted to evaluate the predominance of cold and hot polypectomy for removing colon polyps. Published articles and abstracts from worldwide conferences were searched using the keywords “cold polypectomy”. RCTs that compared either or both the effects or adverse events of cold polypectomy with those of hot polypectomy were collected. The patients’ demographics, endoscopic procedures, No. of examined lesions, lesion size, macroscopic and histologic findings, rates of incomplete resection, bleeding amount, perforation, and length of procedure were extracted from each study. A forest plot analysis was used to verify the relative strength of the effects and adverse events of each procedure. A funnel plot was generated to assess the possibility of publication bias.RESULTS: Ultimately, six RCTs were selected. No significant differences were noted in the average lesion size (less than 10 mm) between the cold and hot polypectomy groups in each study. Further, the rates of complete resection and adverse events, including delayed bleeding, did not differ markedly between cold and hot polypectomy. The average procedural time in the cold polypectomy group was significantly shorter than in the hot polypectomy group.CONCLUSION: Cold polypectomy is a time-saving procedure for removing small polyps with markedly similar curability and safety to hot polypectomy.
基金Item Sponsored by National Natural Science Foundation of China(51074210)
文摘Tension-tension fatigue properties of hot rolled and cold rolled strips with same contents and sizes were measured by using group test method at room temperature in air. The results showed that the fatigue properties of the hot rolled strips were obviously higher than those of the cold rolled strips. The hot rolled strips with similar or higher tensile strength exhibited superior fatigue property over the cold rolled strips. Fracture morphologies observed using scanning electronic microscope （SEM） showed that the hot rolled strips exhibited larger fracture areas, indicating a slightly lower plasticity, and more even fracture microstructure and stable properties. It is feasible and reliable to replace cold rolled strips with hot rolled strips.
文摘This is a comment on a meta-analysis of published studies comparing cold vs hot polypectomy. We believe that the conclusion of this meta-analysis that "cold polypectomy is a time-saving procedure for removing small polyps with markedly similar curability and safety to hot polypectomy" needs more rigorous evidence.
文摘Tomato processing includes a break step, which involves rapid heating of freshly chopped tomatoes to >90°C for hot break, or 60°C to 77°C for cold break. Pectolytic enzyme deactivation is believed to be the key element in the hot break step;therefore, pectin content of different products should be qualitatively distinct. The objective of this study was to investigate the effect of hot break versus cold break on the cell-wall pectin of tomato. Cell-wall pectin from hot and cold break tomato products was isolated and analyzed for carbohydrate composition, degree of polymerization, and degree of esterification. The results showed no observable differences in the cell-wall pectin isolated from the two products, indicating that there was no significant pectolytic breakdown of the tomato in the cold break product, and the pectin might not, by itself, contribute to the differences in the final product viscosity resulting from the two processing techniques.
基金supported in part by National Natural Science Foundation of China(62203127)Basic and Applied Basic Research Project of Guangzhou City(2023A04J1712)+1 种基金The Foshan-HKUST Projects Program(FSUST19-FYTRI01)GDAS’Project of Science and Technology Development(2020GDASYL-20200202001).
文摘As a key component of injection molding,multi-cavity hot runner(MCHR)system faces the crucial problem of polymer melt filling imbalance among the cavities.The thermal imbalance in the system has been considered as the leading cause.Hence,the solution may rest with the synchronization of those heating processes in MCHR system.This paper proposes a’Master-Slave’generalized predictive synchronization control(MS-GPSC)method with’Mr.Slowest’strategy for preheating stage of MCHR system.The core of the proposed method is choosing the heating process with slowest dynamics as the’Master’to track the setpoint,while the other heating processes are treated as‘Slaves’tracking the output of’Master’.This proposed method is shown to have the good ability of temperature synchronization.The corresponding analysis is conducted on parameters tuning and stability,simulations and experiments show the strategy is effective.
文摘Among the bottlenecks that hinder the improvement of the production efficiency of hot stamping are high strength and difficulty in edge cutting and hole punching.Starting from the preparation of hot stamping multiphase microstructure materials,this paper developed a plate quenching die system with controllable surface temperature and prepared four types of hot stamping plates with different martensite volume fractions.Then,straight edge cold cutting experiments were performed to study the influence of cutting clearance and cutting force on fracture quality.The results show that the bright zone is the largest when the cutting clearance is 0.14 mm,and the cutting experience coefficient of the hot stamping sheet with each martensite volume fraction is obtained when the cutting clearance is 0.14 mm.The research results of this paper were applied to the production of hot stamping parts.
基金supported by Gansu Provincial Natural Science Foundation(No.1208RJYA014)Chinese Postdoctoral Science Foundation(No.2009-0460744)+1 种基金Fundamental Research Funds for the Central Universities(No.lzujbky-2014-151)the Natural Science Foundation of China(No.21302079)
文摘Tibetan medicinal plants have been used for more than 2 000 years. In order to find their differences in antioxidant activity, total phenolics and total flavonoids between "hot-nature" and "cold-nature" herbs, we investigated the antioxidant activities of 40 Tibetan herbs from Qinghai plateau, with 20 herbs in cold-nature and 20 herbs in hot-nature. Antioxidant capacities were evaluated by the following methods: scavenging ABTS?+(2, 2′azinobis-(3-ethylbenz-thiazoline-6-sulfonic acid), scavenging O2?-, and Ferric-reducing antioxidant power(FRAP). The effects on inhibition of mitochondrion lipid peroxidation were determined by measuring the formation of TBARS(Thiobarbituric acid reactive substrates). Total phenolics and flavonoids were estimated by Folin-Ciocalteu and Na NO2-Al(NO3)3-Na OH colorimetric methods. Interestingly, the cold-nature herbs displayed higher antioxidant activities than the hot-nature ones, corresponding to nearly three-fold higher total phenolic contents in the cold-nature herbs. Moreover, the antioxidant activities correlated linearly with the levels of total phenolics for both cold-nature and hot-nature herbs, but only with the levels of total flavonoids for the hot-nature herbs. The results suggested that the phenolic compounds, but not the flavonoids, play the major role in antioxidant capacities of the cold-nature herbs. These findings could shed new lights on the study the theory of Tibetan medicine.
文摘In this study,the scale and internal oxidation of hot-rolled ultra-high strength steel sheets were characterized.It was found that both the formation of the scale and the internal oxidation of Si and Mn depended on the coiling temperature and position of the steel sample on the strip coil.At a relatively high coiling temperature,a large amount of internal oxidation was observed on the samples cut from the middle of the coil.The depth of the internal oxidation zone exceeded 10 μm and a thin iron layer covering the scale was observed in some cases.Pickling and cold-rolling experiments were conducted on selected samples.Scale pickling was found to be greatly delayed by the formation of an iron layer,which frequently resulted in under-pickled defects.In addition,pickling of the entire internal oxidation zone was difficult,except at the grain boundaries,where the degree of internal Si and Mn oxidation was enriched.The surface of the cold-rolled steel sheet was ruined by the remaining oxidation zone in the subsurface of the pickled steel.The internal oxidation of hot-rolled ultra-high strength steel must be precisely controlled to improve the subsequent surface quality of cold-rolled steel.
文摘In this study, we propose a new temperature compensation control strategy for a multi-cavity hot runner injection molding system, At first, the melt filling time of each cavity can be measured by installing temperature sensors on the position around end filling area, and filling time difference between the various cavities can be calculated. Then the melt temperature of each hot nozzle can be adjusted automatically by a control strategy established based on the Fuzzy Theory and a program compiled with LABVIEW software. Temperature changes the melt mobility, so the adjustment of temperature can equalize the filling time of the melt in each cavity, which can reduced the mass deviation between each cavity and make product properties of each cavity consistent. The conclusion of the experiment is as follows： For this contact lens box of a four-cavity Hot Runner mold, by applying hot runner temperature compensation control system, time difference can be reduced from 0.05 s to 0.01 s at each cavity, and the mass Standard deviation of the four cavity can be improved from 0.006 to 0.002. The ratio of imbalance can be reduced from 20% to 4%. Hence, the hot runner temperature compensation control system has significant feasibility and high potential in improving melt flow balance of multi-cavity molding application.
文摘Starting from the research on and collection of the damaging factors andindex of the cold and hot damages to citrus, this peper systematically studies the apparent properties in temporal and spatial distribution, differences, relationship of the twokinds of disasters and their impact on citrus production in the Three Gorges area inHubei. It also reveals the important faCt that it is warmer in winter and hotter in springsince the 1980s, which is the cause of departing to two poles of the cold and hot damages, and discusses the alleviating effect to the disasters by the Three Gorges Project.Finally some countermeasures are proposed.
文摘In an injection moulding process, the mould cooling s ystem is very important as an efficient and uniform cooling effect can improve b oth the productivity and part quality. Due to the complexity of the process, muc h research on the mould cooling analysis and cooling design optimization has bee n focused on the core and the cavity, excluding other systems of injection mould s. However, the runner system introduces a considerable amount of heat into the mould. In recent years, more and more hot runner systems are being applied in th e moulding industry to save material and decrease losses of injection pressure. This raises the need to include the hot runner system in the cooling analysis. I n this paper, a photo frame part was studied. The mould was built with a hot run ner system. Two thermal sensors were installed: one measures the temperature of lateral surface of hot runner nozzle; the other measures the plastic temperature from the core side. A pressure sensor was also installed to measure the pressur e of the core impression. Cooling analysis was performed using ABAQUS, ananalysi s software based on the Finite Element Method (FEM). The assembly including core , cavity and plastic part was modeled. Heat conduction from hot runner to cavity and from polymer melt to the mould and force convection on the cooling channel surfaces were studied. The natural convection between the ambient air and the ex terior mould surface was ignored. The simulations were adjusted with the experim ental results to find out the heat input from hot runner and its influence on mo uld cooling. Finally, the optimal cooling design and optimal injection condition were obtained.
文摘In an injection moulding process, the parallelism b et ween the tie bars of the injection moulding machine is very important as it will affect the mould closing and clamping system. In recent years, more and more ho t runner systems are being applied in the moulding industry to save material and decrease the losses of injection pressure. Heat transfer from hot runner system from the fixed half which is secured in the fix machine platen could transmit s o much heat that it may cause high temperature differential between the machine fix platen and moving platen. This will cause the tie bar to become unparallel. Part quality will be compromised and the wear of the tie bar will be excessive. Overhaul of the tie bar may be necessary after a short period of time which is c ostly. This raises the need to analyze the heat transfer from the hot runner sys tem to the machine fix platen and the methods of isolating or minimizing the hea t transfer. In this case study, a photo lens article mould was used. The mould w as built with a direct hot runner nozzle system. Heat conduction from hot runner and machine screw to machine fix platen were studied based on either using high temperature heat insulating plate put in placed between the mould and the mould ing machine fix platen or drill cooling channels in the front mould clamping pla te. The high temperature insulator is very costly as it is made out of glass re inforced polymer composite material. Experimental results were obtained and anal yzed to find the best method to minimize the unwanted heat transfer using the ch eapest and most effective method.
文摘Hot crack is one of common defects in castings, which often results in failure of castings. This work studies the formation of hot crack during cold crucible continuous casting by means of experiments and theoretical analysis. The results show that hot crack occurs on the surface and in the circumference of ingots, where the solidified shell and the solidification front meet each other. The tendency of hot cracking decreases with the increase of withdrawal velocities in some extent. The hot crack is caused mainly by the friction force between the shell and the crucible inner wall, and it takes place when the stress resulting from friction exceeds the tensile strength of the shell. The factors of μ_m, η_t, η_s and η_m, affecting hot cracks are analyzed and verified. In order to decrease the tendency of hot cracks, technical parameters should be optimized by decreasing μ_m, η_t, η_s and η_m.
基金Item Sponsored by National Science and Technology Pillar Program of China(2011BAE13B04)
文摘A new processing method for producing hot dip galvanized steel is designed and tested, in which pickling is skipped. Hot-rolled low carbon steel sheets are roiled with oxide scale in an experimental mill at room temperature, prior to annealing under a 20% hydrogen reducing atmosphere and galvanizing on a hot-dip galvanizing simulator. Micro-cracks formed in the oxide scale during cold rolling roughen the steel surface and enlarge the specific surface. Through-thickness cracks provide transport channels for hydrogen, and hence the reduction of oxide scale is en- hanced. When the sheet is dipped in the zinc bath, cracks are submerged by liquated zinc and the defects are not dis- tinct after hot-dip galvanizing. The overlay coating occludes with rough surface of the sheet, whereby a superior coat- ing adherence is realized.
