BACKGROUND Primary ciliary dyskinesia(PCD)is a rare condition characterised by dysmotile,immotile,or absent cilia.As a result of the impairment in respiratory mucociliary clearance,patients with PCD typically develop ...BACKGROUND Primary ciliary dyskinesia(PCD)is a rare condition characterised by dysmotile,immotile,or absent cilia.As a result of the impairment in respiratory mucociliary clearance,patients with PCD typically develop neonatal respiratory distress,nasal congestion,otitis media and recurrent respiratory infections leading to bronchiectasis and structural lung changes.These changes have been shown by chest computed tomography(CT)to develop in infancy and early childhood.Recent development and refinement of radiation-reducing CT techniques have allowed significant radiation dose reductions,with chest CT doses now in the range of chest radiography(CR).AIM To evaluate the efficacy of ultra-low dose CT(ULDCT)chest in identifying pulmonary changes within a PCD paediatric patient cohort.METHODS Paediatric patients with PCD who presented for routine clinical outpatient follow-up within the study period,were eligible for inclusion in the study.ULDCT and CR were performed on these patients and the results compared.Comparison metrics included radiation dose,subjective and objective image quality and disease severity.RESULTS Six paediatric patients(mean age 9 years)underwent clinically indicated ULDCT chest examinations and CR for surveillance of their PCD.The mean effective dose was 0.08±0.02 mSv,a dose that approximates that of a frontal and lateral chest radiograph.The average Brody II score across the entire cohort was 12.92,with excellent interrater reliability and intra-class correlation coefficient(ICC)of 0.98.The average Chrispin-Norman score on CR was 1 with excellent inter-rater reliability and ICC of 0.92.CONCLUSION ULDCT demonstrates superior diagnostic capabilities,minimal radiation dose penalty,and high interobserver reliability in comparison to CR.Thus,we advocate for ULDCT to be the preferred modality for surveillance imaging in paediatric PCD.展开更多
Neuroinflammation mediated by microglia and oxidative stress play pivotal roles in the development of chronic temporal lobe epilepsy(TLE).We postulated that kainic acid(KA)-Induced status epilepticus triggers microgli...Neuroinflammation mediated by microglia and oxidative stress play pivotal roles in the development of chronic temporal lobe epilepsy(TLE).We postulated that kainic acid(KA)-Induced status epilepticus triggers microglia-dependent inflammation,leading to neuronal damage,a lowered seizure threshold,and the emergence of spontaneous recurrent seizures(SRS).Extensive evidence from our laboratory suggests that dextromethorphan(DM),even in ultra-low doses,has anti-inflammatory and neuroprotective effects in many animal models of neurodegenerative disease.Our results showed that administration of DM(10 ng/kg per day;subcutaneously via osmotic minipump for 4 weeks)significantly mitigated the residual effects of KA,including the frequency of SRS and seizure susceptibility.In addition,DM-treated rats showed improved cognitive function and reduced hippocampal neuronal loss.We found suppressed microglial activation-mediated neuroinflammation and decreased expression of hippocampal gp91^(phox) and p47^(phox) proteins in KA-induced chronic TLE rats.Notably,even after discontinuation of DM treatment,ultra-low doses of DM continued to confer long-term anti-seizure and neuroprotective effects,which were attributed to the inhibition of microglial NADPH oxidase 2 as revealed by mechanistic studies.展开更多
BACKGROUND Incidental pulmonary nodules are an increasingly common finding on computed tomography(CT)scans of the thorax due to the exponential rise in CT examin-ations in everyday practice.The majority of incidental ...BACKGROUND Incidental pulmonary nodules are an increasingly common finding on computed tomography(CT)scans of the thorax due to the exponential rise in CT examin-ations in everyday practice.The majority of incidental pulmonary nodules are benign and correctly identifying the small number of malignant nodules is cha-llenging.Ultra-low-dose CT(ULDCT)has been shown to be effective in diagnosis of respiratory pathology in comparison with traditional standard dose techniques.Our hypothesis was that ULDCT chest combined with model-based iterative reconstruction(MBIR)is comparable to standard dose CT(SDCT)chest in the analysis of pulmonary nodules with significant reduction in radiation dose.AIM To prospectively compare ULDCT chest combined with MBIR with SDCT chest in the analysis of solid pulmonary nodules.METHODS A prospective cohort study was conducted on adult patients(n=30)attending a respiratory medicine outpatient clinic in a tertiary referral university hospital for surveillance of previously detected indeterminate pulmonary nodules on SDCT chest.This study involved the acquisition of a reference SDCT chest followed immediately by an ULDCT chest.Nodule identification,nodule characterisation,nodule measurement,objective and subjective image quality and radiation dose were compared between ULDCT with MBIR and SDCT chest.RESULTS One hundred solid nodules were detected on ULDCT chest and 98 on SDCT chest.There was no significant difference in the characteristics of correctly identified nodules when comparing SDCT chest to ULDCT chest protocols.Signal-to-noise ratio was significantly increased in the ULDCT chest in all areas except in the paraspinal muscle at the maximum cardiac diameter level(P<0.001).The mean subjective image quality score for overall diagnostic acceptability was 8.9/10.The mean dose length product,computed tomography volume dose index and effective dose for the ULDCT chest protocol were 5.592 mGy.cm,0.16 mGy and 0.08 mSv respectively.These were significantly less than the SDCT chest protocol(P<0.001)and represent a radiation dose reduction of 97.6%.CONCLUSION ULDCT chest combined with MBIR is non-inferior to SDCT chest in the analysis of previously identified solid pulmonary nodules and facilitates a large reduction in radiation dose.展开更多
Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet...Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet been understood.In this study,the composition design of Au-Pt alloy with ultra-low MS was achieved through density functional theory(DFT)and experimental methods.The elastic,thermal properties and electronic structure were systematically investigated,the composition range was further optimized and Au75Pt25 was determined to be the most suitable alloy for TM material.The phase composition of this alloy after cold rolling and solid solution was characterized,indicating a single-phase FCC structure.In addition,there is a good validation between the experimental Vickers hardness and the DFT results.This work provides new insights into the compositional optimization of Au-Pt alloys and lays the foundation for alloy development.展开更多
The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution chara...The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.展开更多
The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor...The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.展开更多
BACKGROUND Ultra-low rectal cancer(ULRC),defined as a lesion located within 5 cm of the anal verge,poses considerable clinical challenges because the treatment decision must balance oncological eradication with preser...BACKGROUND Ultra-low rectal cancer(ULRC),defined as a lesion located within 5 cm of the anal verge,poses considerable clinical challenges because the treatment decision must balance oncological eradication with preservation of anal function.Historically,abdominoperineal resection(APR)has served as a standard approach for tumor eradication in these patients,but a permanent stoma significantly reduces patients'quality of life.In contrast,intersphincteric resection(ISR)can maintain anal function,thereby improving quality of life;however,the debate surrounding short-term postoperative complications and long-term prognosis has not been fully resolved.Therefore,large-scale multicenter retrospective cohort studies are crucial to address this issue and provide more reliable data.AIM To address a persistent debate in ULRC management,we compared ISR and APR outcomes through rigorous methodology.METHODS A retrospective analysis of patients undergoing surgery at three centers in China between 2012 and 2023 was performed with propensity score matching(PSM).RESULTS A total of 803 patients(435 in the ISR group and 368 in the APR group)met the inclusion criteria,with 289 comprising each of the two groups after PSM.Over a median follow-up of 47.2 months,the absolute 5-year overall survival(OS)improved by 6.7%with ISR(80.8%vs 74.1%,P=0.032).Cox regression analysis confirmed ISR(HR=0.554,95%CI:0.371-0.828,P=0.004)as an independent protective factor for OS and reduced local recurrence(9.5%vs 12.9%,P=0.019).With respect to short-term complications,despite higher anastomotic leakage rates(11.4%vs 1.0%),ISR significantly reduced total complications(29.4%vs 42.2%,P=0.001)and hospitalization duration(9.8 days vs 12.9 days,P<0.001).Moreover,incision infection,urinary retention,circumferential resection margins,and hospitalization time were greater in the APR group(P<0.05).CONCLUSION The long-term prognosis of ULRC treated with ISR is excellent,with no increase in overall surgical complications or hospital stay duration,indicating that ISR is a feasible alternative to APR for managing ULRC.展开更多
This study investigates the compressive and tensile properties of basalt fiber-reinforced concrete (BFRC) after ultra-low-temperature freeze-thaw cycles. Scanning electron microscope (SEM) analysis was conducted to ex...This study investigates the compressive and tensile properties of basalt fiber-reinforced concrete (BFRC) after ultra-low-temperature freeze-thaw cycles. Scanning electron microscope (SEM) analysis was conducted to examine the deterioration mechanisms caused by freeze-thaw cycles and sulfate erosion. The results show that compressive and tensile strengths increase with basalt fiber dosage. The optimal dosage is 0.2%. With longer exposure to sulfate erosion, both strengths decline significantly. Basalt fibers effectively bridge cracks, control expansion, enhance compactness, and improve concrete performance. Ultra-low-temperature freeze-thaw cycles and sulfate erosion cause rapid crack growth. Sulfate erosion produces crystallization products and expansive substances. These fill cracks, create pressure, and damage the internal structure. Freezing and expansion forces further enlarge voids and cracks. This provides space for expansive substances, worsening concrete deterioration and reducing its performance.展开更多
Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments...Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments,and high-temperature,high-pressure online nuclear magnetic resonance(NMR)displacement experiments,are conducted to reveal the oil/gas mass transfer pattern and oil production mechanisms during CO_(2) flooding in ultra-low permeability reservoirs.The impacts of CO_(2) storage pore range and miscibility on oil production and CO_(2) storage characteristics during CO_(2) flooding are clarified.The CO_(2) flooding process is divided into three stages:oil displacement stage by CO_(2),CO_(2) breakthrough stage,CO_(2) extraction stage.Crude oil expansion and viscosity reduction are the main mechanisms for improving recovery in the CO_(2) displacement stage.After CO_(2) breakthrough,the extraction of light components from the crude oil further enhances oil recovery.During CO_(2) flooding,the contribution of crude oil in large pores to the enhanced recovery exceeds 46%,while crude oil in medium pores serves as a reserve for incremental recovery.After CO_(2) breakthrough,a small portion of the crude oil is extracted and carried into nano-scale pores by CO_(2),becoming residual oil that is hard to recover.As the miscibility increases,the CO_(2) front moves more stably and sweeps a larger area,leading to increased CO_(2) storage range and volume.The CO_(2) full-storage stage contributes the most to the overall CO_(2) storage volume.In the CO_(2) escape stage,the storage mechanism involves partial in-situ storage of crude oil within the initial pore range and the CO_(2) carrying crude oil into smaller pores to increase the volume of stored CO_(2).In the CO_(2) leakage stage,as crude oil is produced,a significant amount of CO_(2) leaks out,causing a sharp decline in the storage efficiency.展开更多
A recent study by Zhang et al developed a neural network-based predictive model for estimating doses to the uninvolved liver during stereotactic body radiation therapy(SBRT)in liver cancer.The study reported a signifi...A recent study by Zhang et al developed a neural network-based predictive model for estimating doses to the uninvolved liver during stereotactic body radiation therapy(SBRT)in liver cancer.The study reported a significant advancement in personalized radiotherapy by improving accuracy and reducing treatment-related toxicity.The model demonstrated strong predictive performance with R-values above 0.8,indicating its potential to improve treatment consistency.However,concerns arise from the small sample size and exclusion criteria,which may limit generalizability.Future studies should incorporate larger,more diverse patient cohorts,explore potential confounding factors such as tumor characteristics and delivery technique variability,and address the long-term effects of SBRT.展开更多
The catalyst cost is a key factor limiting the CO purification of sintering flue gas.Here,an ultra-low-loading high-entropy catalyst was prepared by simple calcination process.By anchoring multiple active metal sites ...The catalyst cost is a key factor limiting the CO purification of sintering flue gas.Here,an ultra-low-loading high-entropy catalyst was prepared by simple calcination process.By anchoring multiple active metal sites in the stable anatase TiO_(2)phase,it shows efficient CO catalytic oxidation activity.The metal components(Pt,Mn,Fe,Co,Ni)were uniformly dispersed on the surface of TiO_(2)in the form of high-entropy compounds and undergo strong metal and support interaction with TiO_(2).The results showed that 0.1(PtMnFeCoNi)/TiO_(2)achieved complete oxidation of CO at 230℃,and its catalytic oxidation ability was significantly better than that of the corresponding monometallic and bimetallic catalysts.The high-entropy component adjusts the electronic environment between the TiO_(2)support and the metal to promote the reduction of the Ti_(3d)band gap,enhances the electron-induced ability of the catalytic system to gas molecules(CO and O_(2)),and exhibits excellent resistance to SO_(2)and H_(2)O.The work is of great significance to understand the synergistic regulation of catalyst activity by multiple metal at the atomic level and provides a strategy for effectively reducing the content of precious metals in the catalyst.展开更多
To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.T...To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.展开更多
Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and...Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.展开更多
Ultra-high dose rate flash radiotherapy(FLASH-RT)has attracted wide attention in the field of radiotherapy in recent years.For FLASH-RT,radiation is delivered at a very high dose rate[usually thousands of times compar...Ultra-high dose rate flash radiotherapy(FLASH-RT)has attracted wide attention in the field of radiotherapy in recent years.For FLASH-RT,radiation is delivered at a very high dose rate[usually thousands of times compared with conventional radiotherapy(CONV-RT)]in an extremely short time.This novel irradiation technique shows a protective effect on normal tissues,also known as the flash effect.At the same time,FLASH-RT is comparable to CONV-RT in terms of tumorkilling efficacy.As basic research dedicates to uncover the mechanisms by which FLASH-RT reduces radiation-induced normal tissue damage,clinical trials of FLASH-RT have been gradually conducted worldwide.This article systematically reviews the evidence of the feasibility and safety of FLASH-RT in clinical practice and offers insights into the future translation of this technology in clinic.展开更多
The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for...The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for dosimetry in FLASHradiotherapy,making it crucial to monitor the dose at ultra-high dose rates accurately and in real time.In this study,the airpressure of the ionization chamber was reduced to perform real-time beam monitoring,and a Faraday cup was used for calibrationfor active dosimetry.To study the saturation effect of the ionization chamber,the drift,attachment,recombination,anddiffusion processes of the electron-ion pairs were modeled using finite-element analysis based on physical phenomenologicalprinciples,and the correction factor was calculated.The experimental results showed that the FLASH ionization chambermeasures good dose linearity at a dose rate of approximately 0.2 Gy/s.When the air pressure of the chamber was adjustedto 10 mbar,the response of the FLASH ionization chamber was linear at a dose rate of approximately 50 Gy/s,with theresiduals within 2%.Furthermore,by using physical phenomenology to resolve the process of electron-ion pair motion inthe sensitive volume of the ionization chamber,the analytical model better describes the saturation effect of carbon ions atultra-high dose rates.The maximum deviation in the calculated correction factor is less than 10%.We studied the saturationeffect in dose measurement,achieving accurate and fast dose and profile position measurement across different dose ratesin a wide range based on the Heavy Ion Research Facility in Lanzhou.展开更多
The emission regulations for heavy-duty diesel engines regarding nitrogen oxide(NO_(x))are becoming increasingly stringent,particularly in relation to cold start cycles.While the twostage selective catalytic reduction...The emission regulations for heavy-duty diesel engines regarding nitrogen oxide(NO_(x))are becoming increasingly stringent,particularly in relation to cold start cycles.While the twostage selective catalytic reduction(SCR)has the potential to achieve ultra-low NO_(x) emissions,several challenges remain,including the accurate prediction of ammonia(NH_(3))storage mass and the co-control of the two-stage SCR.The first step in this study involved the establishment of a rapid control prototype platform to facilitate the development and validation of a two-stage SCR control strategy.Secondly,an initial method for predicting the NH_(3) storage based on the mass conservation law was proposed,which was subsequently improved by filling and emptying experiments.The third step involved the development of a two-stage SCR co-control strategy,including obtaining the steady-state NH_(3) storage target value,dynamic correction for NH_(3) storage target value,regulation of NH_(3) storage,and control of the close-coupled SCR urea injector state.Finally,the two-stage SCR urea injection control strategy was certified under the world harmonized transient cycle(WHTC).The results demonstrate that the composite value of engine outlet NO_(x) emissions under cold and hot start WHTC cycles is 13 g/(kW·h).Meanwhile,the composite value of tailpipe NO_(x) emissions under cold and hot start WHTC cycles is 0.065 g/(kW·h),representing only 14%of the EU VI limit value of 0.46 g/(kW·h).Thus,the findings demonstrate that integrating an accurate NH_(3) storage prediction method with the two-stage SCR co-control function is crucial for heavy-duty diesel engines to achieve ultra-low NO_(x) emissions.展开更多
We read with great interest the recent article by Valenzuela et al.1titled“Dose-response effect of pre-exercise carbohydrates under muscle glycogen unavailability:Insights from McArdle disease”published in the Journ...We read with great interest the recent article by Valenzuela et al.1titled“Dose-response effect of pre-exercise carbohydrates under muscle glycogen unavailability:Insights from McArdle disease”published in the Journal of Sport and Health Science The study's exploration of the effects of varying carbohydrate(CHO)doses on exercise capacity in Mc Ardle disease,a condition characterized by complete muscle glycogen unavailability,is a significant contribution to the field of sports science and metabolic disorders.展开更多
Triple-negative bresst canær(TNBC)metastscis is particularly severe due to its aggressive nsture,leading to rapid disease progresion and significantly reduced survival rates.Rujifang(RJF),a traditional Chinese fo...Triple-negative bresst canær(TNBC)metastscis is particularly severe due to its aggressive nsture,leading to rapid disease progresion and significantly reduced survival rates.Rujifang(RJF),a traditional Chinese formula,has demonstrated potential anti-tumor effects and theability to inhibit TNBC metastasis.However,the efects af varying R.IF dors remain undear.This study utilized Laser-based in vino fow cytometry(IVFC)to monitor circulating tumor cells(CTCs)and evaluate the efficacy of R.IF at different doses.The results indicated that R.IF at the high dose inhibited both the number af CTC:and the formaton of metatatic foci more eflectively compared to the lower dose.TUNEL assays revealed that R.IF trentment promotes apoptosis of tumor cells,with a more pronounced effect observed at the higher dose.Immuno-fluorescence experiments demonstrated that administering a higher dose of R.IF suppreses theеxprescion of Kindlin-1 more effectively in the tumor microenvironment.Although higher doses showed enhanced efficacy,they might also lesd to an increase in side efects.These findings underscore the promise and challenges of using R.IF at high doses for anti-tumor therspy.They highlight the criticnl importance of optimizing the dose of R.JP in the treatment of TNBC and provide valuable insights for its dinical application.展开更多
文摘BACKGROUND Primary ciliary dyskinesia(PCD)is a rare condition characterised by dysmotile,immotile,or absent cilia.As a result of the impairment in respiratory mucociliary clearance,patients with PCD typically develop neonatal respiratory distress,nasal congestion,otitis media and recurrent respiratory infections leading to bronchiectasis and structural lung changes.These changes have been shown by chest computed tomography(CT)to develop in infancy and early childhood.Recent development and refinement of radiation-reducing CT techniques have allowed significant radiation dose reductions,with chest CT doses now in the range of chest radiography(CR).AIM To evaluate the efficacy of ultra-low dose CT(ULDCT)chest in identifying pulmonary changes within a PCD paediatric patient cohort.METHODS Paediatric patients with PCD who presented for routine clinical outpatient follow-up within the study period,were eligible for inclusion in the study.ULDCT and CR were performed on these patients and the results compared.Comparison metrics included radiation dose,subjective and objective image quality and disease severity.RESULTS Six paediatric patients(mean age 9 years)underwent clinically indicated ULDCT chest examinations and CR for surveillance of their PCD.The mean effective dose was 0.08±0.02 mSv,a dose that approximates that of a frontal and lateral chest radiograph.The average Brody II score across the entire cohort was 12.92,with excellent interrater reliability and intra-class correlation coefficient(ICC)of 0.98.The average Chrispin-Norman score on CR was 1 with excellent inter-rater reliability and ICC of 0.92.CONCLUSION ULDCT demonstrates superior diagnostic capabilities,minimal radiation dose penalty,and high interobserver reliability in comparison to CR.Thus,we advocate for ULDCT to be the preferred modality for surveillance imaging in paediatric PCD.
基金supported by the National Major Scientific and Technological Special Project for Significant New Drugs Development(2019zx09301102)the Project of Liaoning Provincial Department of Education(LJKZ0826)the Open Project of National and Local Joint Engineering Research Center for Drug Research and Development of Neurodegenerative Diseases(2022GCYJZX-YB02).
文摘Neuroinflammation mediated by microglia and oxidative stress play pivotal roles in the development of chronic temporal lobe epilepsy(TLE).We postulated that kainic acid(KA)-Induced status epilepticus triggers microglia-dependent inflammation,leading to neuronal damage,a lowered seizure threshold,and the emergence of spontaneous recurrent seizures(SRS).Extensive evidence from our laboratory suggests that dextromethorphan(DM),even in ultra-low doses,has anti-inflammatory and neuroprotective effects in many animal models of neurodegenerative disease.Our results showed that administration of DM(10 ng/kg per day;subcutaneously via osmotic minipump for 4 weeks)significantly mitigated the residual effects of KA,including the frequency of SRS and seizure susceptibility.In addition,DM-treated rats showed improved cognitive function and reduced hippocampal neuronal loss.We found suppressed microglial activation-mediated neuroinflammation and decreased expression of hippocampal gp91^(phox) and p47^(phox) proteins in KA-induced chronic TLE rats.Notably,even after discontinuation of DM treatment,ultra-low doses of DM continued to confer long-term anti-seizure and neuroprotective effects,which were attributed to the inhibition of microglial NADPH oxidase 2 as revealed by mechanistic studies.
文摘BACKGROUND Incidental pulmonary nodules are an increasingly common finding on computed tomography(CT)scans of the thorax due to the exponential rise in CT examin-ations in everyday practice.The majority of incidental pulmonary nodules are benign and correctly identifying the small number of malignant nodules is cha-llenging.Ultra-low-dose CT(ULDCT)has been shown to be effective in diagnosis of respiratory pathology in comparison with traditional standard dose techniques.Our hypothesis was that ULDCT chest combined with model-based iterative reconstruction(MBIR)is comparable to standard dose CT(SDCT)chest in the analysis of pulmonary nodules with significant reduction in radiation dose.AIM To prospectively compare ULDCT chest combined with MBIR with SDCT chest in the analysis of solid pulmonary nodules.METHODS A prospective cohort study was conducted on adult patients(n=30)attending a respiratory medicine outpatient clinic in a tertiary referral university hospital for surveillance of previously detected indeterminate pulmonary nodules on SDCT chest.This study involved the acquisition of a reference SDCT chest followed immediately by an ULDCT chest.Nodule identification,nodule characterisation,nodule measurement,objective and subjective image quality and radiation dose were compared between ULDCT with MBIR and SDCT chest.RESULTS One hundred solid nodules were detected on ULDCT chest and 98 on SDCT chest.There was no significant difference in the characteristics of correctly identified nodules when comparing SDCT chest to ULDCT chest protocols.Signal-to-noise ratio was significantly increased in the ULDCT chest in all areas except in the paraspinal muscle at the maximum cardiac diameter level(P<0.001).The mean subjective image quality score for overall diagnostic acceptability was 8.9/10.The mean dose length product,computed tomography volume dose index and effective dose for the ULDCT chest protocol were 5.592 mGy.cm,0.16 mGy and 0.08 mSv respectively.These were significantly less than the SDCT chest protocol(P<0.001)and represent a radiation dose reduction of 97.6%.CONCLUSION ULDCT chest combined with MBIR is non-inferior to SDCT chest in the analysis of previously identified solid pulmonary nodules and facilitates a large reduction in radiation dose.
基金financially supported by the National Key R&D Program of China(No.2021YFC2202300)the National Natural Science Foundation of China(NSFC)(No.51974258)the National College Students Innovation and Entrepreneurship Training Program(No.S202210699134).
文摘Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet been understood.In this study,the composition design of Au-Pt alloy with ultra-low MS was achieved through density functional theory(DFT)and experimental methods.The elastic,thermal properties and electronic structure were systematically investigated,the composition range was further optimized and Au75Pt25 was determined to be the most suitable alloy for TM material.The phase composition of this alloy after cold rolling and solid solution was characterized,indicating a single-phase FCC structure.In addition,there is a good validation between the experimental Vickers hardness and the DFT results.This work provides new insights into the compositional optimization of Au-Pt alloys and lays the foundation for alloy development.
基金financially supported by the National Natural Science Foundation of China(No.52174306)the Fundamental Research Funds for the Central Universities(Nos.N2225023 and N2425006)the Basic Research Projects of Liaoning Provincial Department of Education(No.LJ212410148027)。
文摘The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.
基金supported by National Natural Science Foundation of China(52072173)International Science and Technology cooperation program of Jiangsu Province(SBZ2022000084)Funding for Outstanding Doctoral Dissertation in NUAA(BCXJ23-10).
文摘The stable operation of supercapacitors at extremely low temperatures is crucial for applications in harsh envi-ronments.Unfortunately,conventional inorganic electrodes suffer from sluggish diffusion kinetics and poor cycling stability for proton pseudocapacitors.Here,a redox-active polymer poly(1,5-diaminonaphthalene)is developed and synthesized as an ultrafast,high-mass loading,and durable pseudocapacitive anode.The charge storage of poly(1,5-diaminonaphthalene)depends on the reversible coordination reaction of the C¼N group with Hþ,which enables fast kinetics associated with surface-controlled reactions.The 3D-printed organic electrode delivers a remarkable areal capacitance(8.43 F cm^(-2)at 30.78 mg cm^(-2))and thickness-independent rate per-formance.Furthermore,the 3D-printed proton pseudocapacitor exhibits great low-temperature tolerance and delivers a high energy density of 0.44 mWh cm^(-2)at-60℃,as well as operates well even at-80℃.This work signifies that combining organic material design with 3D hierarchical network electrode construction can provide a promising solution for low-temperature-resistant supercapacitors.
基金Supported by Natural Science Foundation of Fujian Province,No.2023J011819.
文摘BACKGROUND Ultra-low rectal cancer(ULRC),defined as a lesion located within 5 cm of the anal verge,poses considerable clinical challenges because the treatment decision must balance oncological eradication with preservation of anal function.Historically,abdominoperineal resection(APR)has served as a standard approach for tumor eradication in these patients,but a permanent stoma significantly reduces patients'quality of life.In contrast,intersphincteric resection(ISR)can maintain anal function,thereby improving quality of life;however,the debate surrounding short-term postoperative complications and long-term prognosis has not been fully resolved.Therefore,large-scale multicenter retrospective cohort studies are crucial to address this issue and provide more reliable data.AIM To address a persistent debate in ULRC management,we compared ISR and APR outcomes through rigorous methodology.METHODS A retrospective analysis of patients undergoing surgery at three centers in China between 2012 and 2023 was performed with propensity score matching(PSM).RESULTS A total of 803 patients(435 in the ISR group and 368 in the APR group)met the inclusion criteria,with 289 comprising each of the two groups after PSM.Over a median follow-up of 47.2 months,the absolute 5-year overall survival(OS)improved by 6.7%with ISR(80.8%vs 74.1%,P=0.032).Cox regression analysis confirmed ISR(HR=0.554,95%CI:0.371-0.828,P=0.004)as an independent protective factor for OS and reduced local recurrence(9.5%vs 12.9%,P=0.019).With respect to short-term complications,despite higher anastomotic leakage rates(11.4%vs 1.0%),ISR significantly reduced total complications(29.4%vs 42.2%,P=0.001)and hospitalization duration(9.8 days vs 12.9 days,P<0.001).Moreover,incision infection,urinary retention,circumferential resection margins,and hospitalization time were greater in the APR group(P<0.05).CONCLUSION The long-term prognosis of ULRC treated with ISR is excellent,with no increase in overall surgical complications or hospital stay duration,indicating that ISR is a feasible alternative to APR for managing ULRC.
文摘This study investigates the compressive and tensile properties of basalt fiber-reinforced concrete (BFRC) after ultra-low-temperature freeze-thaw cycles. Scanning electron microscope (SEM) analysis was conducted to examine the deterioration mechanisms caused by freeze-thaw cycles and sulfate erosion. The results show that compressive and tensile strengths increase with basalt fiber dosage. The optimal dosage is 0.2%. With longer exposure to sulfate erosion, both strengths decline significantly. Basalt fibers effectively bridge cracks, control expansion, enhance compactness, and improve concrete performance. Ultra-low-temperature freeze-thaw cycles and sulfate erosion cause rapid crack growth. Sulfate erosion produces crystallization products and expansive substances. These fill cracks, create pressure, and damage the internal structure. Freezing and expansion forces further enlarge voids and cracks. This provides space for expansive substances, worsening concrete deterioration and reducing its performance.
基金Supported by the National Natural Science Foundation of China(52274053)Natural Science Foundation of Beijing(3232028).
文摘Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments,and high-temperature,high-pressure online nuclear magnetic resonance(NMR)displacement experiments,are conducted to reveal the oil/gas mass transfer pattern and oil production mechanisms during CO_(2) flooding in ultra-low permeability reservoirs.The impacts of CO_(2) storage pore range and miscibility on oil production and CO_(2) storage characteristics during CO_(2) flooding are clarified.The CO_(2) flooding process is divided into three stages:oil displacement stage by CO_(2),CO_(2) breakthrough stage,CO_(2) extraction stage.Crude oil expansion and viscosity reduction are the main mechanisms for improving recovery in the CO_(2) displacement stage.After CO_(2) breakthrough,the extraction of light components from the crude oil further enhances oil recovery.During CO_(2) flooding,the contribution of crude oil in large pores to the enhanced recovery exceeds 46%,while crude oil in medium pores serves as a reserve for incremental recovery.After CO_(2) breakthrough,a small portion of the crude oil is extracted and carried into nano-scale pores by CO_(2),becoming residual oil that is hard to recover.As the miscibility increases,the CO_(2) front moves more stably and sweeps a larger area,leading to increased CO_(2) storage range and volume.The CO_(2) full-storage stage contributes the most to the overall CO_(2) storage volume.In the CO_(2) escape stage,the storage mechanism involves partial in-situ storage of crude oil within the initial pore range and the CO_(2) carrying crude oil into smaller pores to increase the volume of stored CO_(2).In the CO_(2) leakage stage,as crude oil is produced,a significant amount of CO_(2) leaks out,causing a sharp decline in the storage efficiency.
文摘A recent study by Zhang et al developed a neural network-based predictive model for estimating doses to the uninvolved liver during stereotactic body radiation therapy(SBRT)in liver cancer.The study reported a significant advancement in personalized radiotherapy by improving accuracy and reducing treatment-related toxicity.The model demonstrated strong predictive performance with R-values above 0.8,indicating its potential to improve treatment consistency.However,concerns arise from the small sample size and exclusion criteria,which may limit generalizability.Future studies should incorporate larger,more diverse patient cohorts,explore potential confounding factors such as tumor characteristics and delivery technique variability,and address the long-term effects of SBRT.
文摘The catalyst cost is a key factor limiting the CO purification of sintering flue gas.Here,an ultra-low-loading high-entropy catalyst was prepared by simple calcination process.By anchoring multiple active metal sites in the stable anatase TiO_(2)phase,it shows efficient CO catalytic oxidation activity.The metal components(Pt,Mn,Fe,Co,Ni)were uniformly dispersed on the surface of TiO_(2)in the form of high-entropy compounds and undergo strong metal and support interaction with TiO_(2).The results showed that 0.1(PtMnFeCoNi)/TiO_(2)achieved complete oxidation of CO at 230℃,and its catalytic oxidation ability was significantly better than that of the corresponding monometallic and bimetallic catalysts.The high-entropy component adjusts the electronic environment between the TiO_(2)support and the metal to promote the reduction of the Ti_(3d)band gap,enhances the electron-induced ability of the catalytic system to gas molecules(CO and O_(2)),and exhibits excellent resistance to SO_(2)and H_(2)O.The work is of great significance to understand the synergistic regulation of catalyst activity by multiple metal at the atomic level and provides a strategy for effectively reducing the content of precious metals in the catalyst.
文摘To monitor nuclear and radiation emergencies,it is crucial to obtain accurate in situ measurements of the environmentalγ radiation dose rate from key radionuclides,particularly for large radioactive surface sources.The methods currently used for measuring dose rates are inadequate for obtaining the dose rates of key radionuclides and have large angular response errors when monitoring surface sources.To address this practical problem,this study proposes three methods for measuring the dose rate:the weighted peak total ratio,mean value regression,and numerical integration methods.These methods are based on energy-spectrum measurement data,and they were theoretically derived and numerically evaluated.Finally,a 1-m-long hexagonal radioactive surface source was integrated into a larger surface source.In situ measurement experiments were conducted on a large radioactive surface source using a dose-rate meter and a portable HPGespectrometer to analyze the errors of the three aforementioned methods and verify their validity.
基金supported by the National Natural Science Foundation of China(No.12375314)。
文摘Tungsten is considered the most promising plasma-facing material for fusion reactors with exceptional performance.Under certain conditions,activated tungsten dust can be generated through plasma–wall interactions and released into the atmosphere.Activated tungsten migrates downward in the soil after atmospheric deposition.However,effective methods for evaluating the environmental dose of gamma rays emitted by activated tungsten are still lacking.Consequently,a method for evaluating the air-absorbed dose rate of activated tungsten dust was proposed considering soil attenuation.Key parameters including the mass attenuation coefficient and energy absorption build-up factor were determined for the main gamma ray energies of radionuclides within the activated tungsten dust.Additionally,air-absorbed dose rates were calculated by assuming that radioactive sources were located at different soil depths and radii.It was found that a soil depth of 50 cm significantly attenuated the environmental dose by 99.9%,whereas the air-absorbed dose rates within the horizontal distance of 500 cm accounted for 91%of the total dose rate.Therefore,this study underscored the importance of soil attenuation in environmental dose assessments,which must be carefully re-examined for the safety analysis of fusion reactors.
文摘Ultra-high dose rate flash radiotherapy(FLASH-RT)has attracted wide attention in the field of radiotherapy in recent years.For FLASH-RT,radiation is delivered at a very high dose rate[usually thousands of times compared with conventional radiotherapy(CONV-RT)]in an extremely short time.This novel irradiation technique shows a protective effect on normal tissues,also known as the flash effect.At the same time,FLASH-RT is comparable to CONV-RT in terms of tumorkilling efficacy.As basic research dedicates to uncover the mechanisms by which FLASH-RT reduces radiation-induced normal tissue damage,clinical trials of FLASH-RT have been gradually conducted worldwide.This article systematically reviews the evidence of the feasibility and safety of FLASH-RT in clinical practice and offers insights into the future translation of this technology in clinic.
文摘The ionization chamber produces significant space-charge and ion recombination effects at ultra-high dose rates,posing achallenge for dose monitoring.In addition,there is no generally accepted ion correction model for dosimetry in FLASHradiotherapy,making it crucial to monitor the dose at ultra-high dose rates accurately and in real time.In this study,the airpressure of the ionization chamber was reduced to perform real-time beam monitoring,and a Faraday cup was used for calibrationfor active dosimetry.To study the saturation effect of the ionization chamber,the drift,attachment,recombination,anddiffusion processes of the electron-ion pairs were modeled using finite-element analysis based on physical phenomenologicalprinciples,and the correction factor was calculated.The experimental results showed that the FLASH ionization chambermeasures good dose linearity at a dose rate of approximately 0.2 Gy/s.When the air pressure of the chamber was adjustedto 10 mbar,the response of the FLASH ionization chamber was linear at a dose rate of approximately 50 Gy/s,with theresiduals within 2%.Furthermore,by using physical phenomenology to resolve the process of electron-ion pair motion inthe sensitive volume of the ionization chamber,the analytical model better describes the saturation effect of carbon ions atultra-high dose rates.The maximum deviation in the calculated correction factor is less than 10%.We studied the saturationeffect in dose measurement,achieving accurate and fast dose and profile position measurement across different dose ratesin a wide range based on the Heavy Ion Research Facility in Lanzhou.
基金supported by the National Natural Science Foundation of China(No.51921004).
文摘The emission regulations for heavy-duty diesel engines regarding nitrogen oxide(NO_(x))are becoming increasingly stringent,particularly in relation to cold start cycles.While the twostage selective catalytic reduction(SCR)has the potential to achieve ultra-low NO_(x) emissions,several challenges remain,including the accurate prediction of ammonia(NH_(3))storage mass and the co-control of the two-stage SCR.The first step in this study involved the establishment of a rapid control prototype platform to facilitate the development and validation of a two-stage SCR control strategy.Secondly,an initial method for predicting the NH_(3) storage based on the mass conservation law was proposed,which was subsequently improved by filling and emptying experiments.The third step involved the development of a two-stage SCR co-control strategy,including obtaining the steady-state NH_(3) storage target value,dynamic correction for NH_(3) storage target value,regulation of NH_(3) storage,and control of the close-coupled SCR urea injector state.Finally,the two-stage SCR urea injection control strategy was certified under the world harmonized transient cycle(WHTC).The results demonstrate that the composite value of engine outlet NO_(x) emissions under cold and hot start WHTC cycles is 13 g/(kW·h).Meanwhile,the composite value of tailpipe NO_(x) emissions under cold and hot start WHTC cycles is 0.065 g/(kW·h),representing only 14%of the EU VI limit value of 0.46 g/(kW·h).Thus,the findings demonstrate that integrating an accurate NH_(3) storage prediction method with the two-stage SCR co-control function is crucial for heavy-duty diesel engines to achieve ultra-low NO_(x) emissions.
文摘We read with great interest the recent article by Valenzuela et al.1titled“Dose-response effect of pre-exercise carbohydrates under muscle glycogen unavailability:Insights from McArdle disease”published in the Journal of Sport and Health Science The study's exploration of the effects of varying carbohydrate(CHO)doses on exercise capacity in Mc Ardle disease,a condition characterized by complete muscle glycogen unavailability,is a significant contribution to the field of sports science and metabolic disorders.
基金supported by the National Key Re-search and Development Program of China(2021YFF0502900,2019YFC1604604)the grant of Peak Climbing Project of Foshan Hospital of Tra-ditional Chinese Medicine,Traditional Chinese Medicine Bureat of Guangdong Province Project(No.20213018)+2 种基金the Special Fund for Research on National Major Research Instruuments of China(Grant No.62027824)Scientific Research Fund of Education Department of Yunnan Province(2023Y0619)Biomedical Projects of Yun-nan Key Science and Technology Program(202302AA310046).
文摘Triple-negative bresst canær(TNBC)metastscis is particularly severe due to its aggressive nsture,leading to rapid disease progresion and significantly reduced survival rates.Rujifang(RJF),a traditional Chinese formula,has demonstrated potential anti-tumor effects and theability to inhibit TNBC metastasis.However,the efects af varying R.IF dors remain undear.This study utilized Laser-based in vino fow cytometry(IVFC)to monitor circulating tumor cells(CTCs)and evaluate the efficacy of R.IF at different doses.The results indicated that R.IF at the high dose inhibited both the number af CTC:and the formaton of metatatic foci more eflectively compared to the lower dose.TUNEL assays revealed that R.IF trentment promotes apoptosis of tumor cells,with a more pronounced effect observed at the higher dose.Immuno-fluorescence experiments demonstrated that administering a higher dose of R.IF suppreses theеxprescion of Kindlin-1 more effectively in the tumor microenvironment.Although higher doses showed enhanced efficacy,they might also lesd to an increase in side efects.These findings underscore the promise and challenges of using R.IF at high doses for anti-tumor therspy.They highlight the criticnl importance of optimizing the dose of R.JP in the treatment of TNBC and provide valuable insights for its dinical application.
文摘目的:探讨在新生儿胸部CT检查中,结合使用低管电压、固定管电流以及不同权重的iDose4重建技术对图像质量的影响,并评估其可行性。方法:搜集80例行CT检查的新生儿,随机分到A、B两组,A组采用自动曝光控制技术,B组采用固定管电流扫描(33 mA),采用iDose^(4)重建法重建出1~7级不同权重的肺窗和纵隔窗图像,并对比分析图像质量。记录患儿的CTDIVOL,后依据回归模型计算出体型特异性剂量估算值(size specific dose estimate,SSDE),并对比分析。结果:A、B两组患儿iDose^(4)重建算法的最佳权重肺窗为3级,纵隔窗为4级;A、B组患儿CTDIVOL分别为(1.04±0.21)mGy和(0.91±0.18)mGy,A组较B组高12.5%(t=2.17,P=0.04);A、B组患儿的SSDE分别为(2.41±0.36)mGy和(2.07±0.32)mGy,A组较B组高15.4%(t=3.19,P<0.05);A、B组患儿CTDIVOL离散度分别为20.2%(0.21/1.04)和19.8%(0.18/0.91),A、B组患儿SSDE离散度分别为14.5%(0.36/2.41)和15.5%(0.32/2.07)。结论:在新生儿CT检查时推荐使用低管电压、低固定管电流及适当的重建算法权重相结合的方法进行扫描,同时,推荐采用SSDE评估新生儿的辐射剂量。
