The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation met...The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation methods, a new approach based on the shadow area percentage （SAP） that can be used to quantify surface roughness is proposed in this article. Firstly, by the help of laser scanning technique, the three-dimensional model of the surface of rock discontinuity was established. Secondly, a light source was simulated, and there would be some shadows produced on the model surface. Thirdly, to obtain the value of SAP of each specimen, the shadow detection technique was introduced for use. Fourthly, compared with the result from direct shear testing and based on statistics, an empirical for- mula was found among SAP, normal stress, and shear strength. Data of Yujian （~ River were used as an example, and the following conclusions have been made. （1） In the case of equal normal stress, the peak shear stress is positively proportional to the SAP. （2） The formula for estimating was derived, and the predictions of peak-shear strength made with this equation well agreed with the experimental re- suits obtained in laboratory tests.展开更多
The effect of micro structure on the corrosion resistance of Al_(x)CoCrFeNiC_(0.01)(x=0.2,0.7,and 1.2)high-entropy alloys(HEAs) was systematically studied in this work.The microstructure evolution by regulating the Al...The effect of micro structure on the corrosion resistance of Al_(x)CoCrFeNiC_(0.01)(x=0.2,0.7,and 1.2)high-entropy alloys(HEAs) was systematically studied in this work.The microstructure evolution by regulating the Al content was analyzed in detail.Corrosion behavior was in situ monitored using the scanning vibration electrode technique,as well as some traditional electrochemical measurements.It is interesting to find that the compositions of body-centered cubic(bcc) and face-centered cubic(fcc)phases changed with the rising Al content,while the corresponding electrochemical responses for both phases were discriminated using the scanning Kelvin probe force microscopy method.Cr element was mainly distributed in the bcc phase for Al0.2(x=0.2) alloy,while its distribution changed to the fcc phase for the A10.7 and Al1.2alloys.The micro-galvanic corrosion cells formed between Cr-depleted and Cr-rich phases,resulting in the localized corrosion behaviors for the Al_(x)CoCrFeNiC_(0.01) HEAs,and the order for anti-corrosion property was Al0.2>Al1.2> Al0.7 HEAs.展开更多
Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in...Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.展开更多
The third-order optical nonlinearities of [（CH3）4N]Au（dmit）2 （dmit = 4,5-dithiolate-1,3-dithiole-2-thione） at 532 nm and 1064 nm are investigated using the Z-scan technique with pulses of picoseconds duration. T...The third-order optical nonlinearities of [（CH3）4N]Au（dmit）2 （dmit = 4,5-dithiolate-1,3-dithiole-2-thione） at 532 nm and 1064 nm are investigated using the Z-scan technique with pulses of picoseconds duration. The Z-scan spectra reveal a strong nonlinear absorption （reverse saturable absorption） and a negative nonlinear refraction at 532 nm. No nonlinear absorption is observed at 1064 nm. The molecular second-order hyperpolarizability γ for the [（CH3）4N]Au（dmit）2 molecule at 532nm is estimated to be as high as （2.1 ±0.1） × 10^-31 esu, which is nearly three times larger than that at 1064 nm. The mechanism responsible for the difference between the results is analysed. Nonlinear transmission measurements suggest that this material has potential applications in optical limiting.展开更多
Side channel attack may result in user key leakage as scan test techniques are applied for crypto-graphic chips. Many secure scan designs have been proposed to protect the user key. This paper meticulously selects thr...Side channel attack may result in user key leakage as scan test techniques are applied for crypto-graphic chips. Many secure scan designs have been proposed to protect the user key. This paper meticulously selects three current scan test techniques, analyses their advantages and disadvantages and also compares them in security and area overhead. Users can choose one of them according to the requirements and further combination can be implemented to achieve better performance.展开更多
The nonlinear optical properties of a phosphate vitreous system [（ZnO）x-（MgO）30-x-（P2O5）70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using th...The nonlinear optical properties of a phosphate vitreous system [（ZnO）x-（MgO）30-x-（P2O5）70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive （NLR） index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10-10 cm2·W-1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index （n2） and absorption coefficient （β） of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching.展开更多
Z-scan technique is an effective tool for measuring the optical nonlinearity of the materials. By using this technique the measurement was made for total protein and albumin. The nonlinear refractive index of the tota...Z-scan technique is an effective tool for measuring the optical nonlinearity of the materials. By using this technique the measurement was made for total protein and albumin. The nonlinear refractive index of the total protein and albumin were found to vary linearly with concentration. Hence by calculating the nonlinear refractive index it is possible to measure their concentration in the sample. The values measured thus are found in equivalence with conventional colorimetric method.展开更多
The third-order nonlinear optical properties of two dmit organometallic complexes, [(CH3)4N] [Au(C3S5)2] (MeAu) and [(CH3)4N][Ni(C3S5)2] (Me Ni) in acetone solutions, were characterized us- ing a short pulse Z-scan te...The third-order nonlinear optical properties of two dmit organometallic complexes, [(CH3)4N] [Au(C3S5)2] (MeAu) and [(CH3)4N][Ni(C3S5)2] (Me Ni) in acetone solutions, were characterized us- ing a short pulse Z-scan technique at 1064 nm wavelength. Self-defocusing effects were found in both samples and stronger saturable absorp-tion was observed in MeNi solution comparing with that of MeAu. The origins were analyzed for the differences between the results. Two figures of merit W and T were also calculated to evalu-ate the suitability of two materials for all-optical integrated devices. The results of W=22.84 and T≈0 of MeAu make it an excellent candidate for the all-optical applications.展开更多
Background: The accuracy of the final prosthesis is affected by the final impression technique and master cast production. The aim of the present study was to evaluate the effect of the functional impression technique...Background: The accuracy of the final prosthesis is affected by the final impression technique and master cast production. The aim of the present study was to evaluate the effect of the functional impression technique with various impression materials on the surface characteristic of dental stone casts and their clinical effect on the retention of complete dentures. Method: Specimens of three impression materials/stone casts were fabricated. The specimens of the impression materials/stone casts were divided into three equal groups (I, II, and III). The impression materials used were as follows: tissue conditioner group (I), zinc oxide (ZEO) (group II) and poly (vinyl siloxane) (PVS) (group III). Cylindrical split aluminium moulds were designed to receive the impression materials and the stone mixture. The surface roughness of the stone cast specimens of the three groups (I, II, and III) was measured with a surface profilometer and analyzed by a scanning electron microscope. A clinical study included five severely resorbed mandibular edentulous alveolar ridges and edentulous maxillary arches. Each subject received three heat-cured acrylic resin dentures, fabricated using the functional impression technique. The three dentures were identical except for the different impression materials used from Groups I, II and III. The retentive force of each denture for each subject was measured. Result: The results of this study revealed that the mean value of surface roughness of the stone cast surface of group I was higher than group II and group III. A statistically significant difference was observed in surface roughness and the retentive dislodging force between the three studied groups. Although using a tissue conditioner as a functional impression material led to a high level of surface roughness and good retention, it could not produce the same smooth surface quality of PVS or ZEO. These data were supported by SEM analysis. The complete dentures for these patients require important oral and denture hygiene care. Conclusion: Complete dentures made using functional impression technique with PVC as a final impression material are more comfortable, retentive and stable.展开更多
BACKGROUND Coronary computed tomography angiography(CCTA)is the preferred noninvasive examination method for coronary heart disease.However,the radiation from computed tomography has become a concern since public awar...BACKGROUND Coronary computed tomography angiography(CCTA)is the preferred noninvasive examination method for coronary heart disease.However,the radiation from computed tomography has become a concern since public awareness of radiation hazards continue to increase.AIM To explore the value of multiple dose reduction techniques for CCTA.METHODS Consecutive normal and overweight patients were prospectively divided into two groups:Group A1,patients who received multiple dose reduction scans(n=82);and group A2,patients who received conventional scans(n=39).The scan parameters for group A1 were as follows:Isocentric scan,tube voltage=80 kV,and tube current control using 80%smart milliampere.The scan parameters for group A2 were as follows:Normal position,tube voltage=100 kV,and smart milliampere.RESULTS The average effective doses(EDs)for groups A1 and A2 were 1.13±0.35 and 3.36±1.30 mSv,respectively.There was a statistically significant difference in ED between the two groups(P<0.01).Furthermore,noise was significantly lower,and both signal-to-noise ratio and contrast signal-to-noise ratio were higher in group A2 when compared to group A1(P<0.01).Moreover,the subjective image quality(IQ)scores were excellent in both groups,in which there was no significant difference in subjective IQ score between the two groups(P=0.12).CONCLUSION Multiple dose reduction scan techniques can significantly decrease the ED of patients receiving CCTA examinations for clinical diagnosis.展开更多
[Objectives]To study the immediate-release mechanism of dehydrotrametenolic acid and dehydroeburicoic acid in Poriae Cutis total triterpenoids tablets by liquid-solid compacts technique.[Methods] Taking dehydrotramete...[Objectives]To study the immediate-release mechanism of dehydrotrametenolic acid and dehydroeburicoic acid in Poriae Cutis total triterpenoids tablets by liquid-solid compacts technique.[Methods] Taking dehydrotrametenolic acid and dehydroeburicoic acid as indicators,differences in dissolution were compared between liquid-solid compressed tablets and crude drug of total triterpenoids in Poriae Cutis;crude drug,powder of liquid-solid compressed tablets and excipients of liquid-solid compressed tablets were characterized by differential scanning calorimetry( DSC).[Results]Liquid-solid compact technique could significantly improve dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid. The total dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid in Poriae Cutis total triterpenoids tablets was 92%,t50( time for 50% total dissolution rate) and t_D( time for 63. 2% total dissolution rate) were 11. 18 min and 22. 71 min; the total dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid in crude drug of total triterpenoids was 29%,and t50 and t_D were231. 06 min and 359. 23 min. DSC showed that there was no mutual interaction between excipients and total triterpenoids in Poriae Cutis; on the DSC curve for powder of liquid-solid compressed tablets,the absorption peak vanished completely,indicating that the drug exists in the amorphous form in the liquid-solid powder.[Conclusions] Liquid-solid compact technique can increase the dissolution rate of total triterpenoids in Poriae Cutis and allow rapid release of poorly water soluble drugs.展开更多
Previous research has demonstrated the feasibility of repairing nerve defects through acellular allogeneic nerve grafting with bone marrow mesenchymal stem cells.However,adult tissue–derived mesenchymal stem cells en...Previous research has demonstrated the feasibility of repairing nerve defects through acellular allogeneic nerve grafting with bone marrow mesenchymal stem cells.However,adult tissue–derived mesenchymal stem cells encounter various obstacles,including limited tissue sources,invasive acquisition methods,cellular heterogeneity,purification challenges,cellular senescence,and diminished pluripotency and proliferation over successive passages.In this study,we used induced pluripotent stem cell-derived mesenchymal stem cells,known for their self-renewal capacity,multilineage differentiation potential,and immunomodulatory characteristics.We used induced pluripotent stem cell-derived mesenchymal stem cells in conjunction with acellular nerve allografts to address a 10 mm-long defect in a rat model of sciatic nerve injury.Our findings reveal that induced pluripotent stem cell-derived mesenchymal stem cells exhibit survival for up to 17 days in a rat model of peripheral nerve injury with acellular nerve allograft transplantation.Furthermore,the combination of acellular nerve allograft and induced pluripotent stem cell-derived mesenchymal stem cells significantly accelerates the regeneration of injured axons and improves behavioral function recovery in rats.Additionally,our in vivo and in vitro experiments indicate that induced pluripotent stem cell-derived mesenchymal stem cells play a pivotal role in promoting neovascularization.Collectively,our results suggest the potential of acellular nerve allografts with induced pluripotent stem cell-derived mesenchymal stem cells to augment nerve regeneration in rats,offering promising therapeutic strategies for clinical translation.展开更多
To resolve inflation of inertial confinement fusion (ICF) target and encapsulation of micro inflation hole with adhesive, a scanning probe microscope (SPM) diamond microprobe was used as the cutting tool with SPM in c...To resolve inflation of inertial confinement fusion (ICF) target and encapsulation of micro inflation hole with adhesive, a scanning probe microscope (SPM) diamond microprobe was used as the cutting tool with SPM in contact mode. Some parameters influencing the quality of micro inflation hole, such as the scanning direction of the diamond tip, the scanning rate and the contact force are discussed. Accurate taper hole was achieved whose climension and precision could meet the requirements of inflation and encapsulation technique of micro hole. The experimental results show that using SPM diamond microprobe as the cutting tool and with special processing technique, the precision machining of target capsule's taper inflation hole can be realized. A novel operative technology for filling high Z gas to target is provided.展开更多
A novel procedure to calibrate the scanning line-structured laser sensor is presented. A drone composed of two orthogonal planes is designed, with the result that camera parameters and light-plane equation parameters ...A novel procedure to calibrate the scanning line-structured laser sensor is presented. A drone composed of two orthogonal planes is designed, with the result that camera parameters and light-plane equation parameters is achieved simultaneously.展开更多
In conventional pulsed laser deposition （PLD） technique, plume deflection and composition distribution change with the laser incident direction and pulse energy, then causing uneven film thickness and composition di...In conventional pulsed laser deposition （PLD） technique, plume deflection and composition distribution change with the laser incident direction and pulse energy, then causing uneven film thickness and composition distribution for a multicomponent film and eventually leading to low device quality and low rate of final products. We present a novel method based on PLD for depositing large CIGS films with uni- form thickness and stoichiometry. By oscillating a mirror placed coaxially with the incident laser beam, the laser＇s focus is scanned across the rotating target surface. This arrangement maintains a constant re- flectance and optical distance, ensuring that a consistent energy density is delivered to the target surface by each laser pulse. Scanning the laser spot across the target suppresses the formation of micro-columns, and thus the plume deflection effect that reduces film uniformity in conventional PLD technique is eliminated. This coaxial scanning PLD method is used to deposit a CIGS film, 500 nm thick, with thickness uniformity exceeding ±3% within a 5 cm diameter, and exhibiting a highly homogeneous elemental distribution.展开更多
基金supported by the China Geological Survey (No.1212011014030)the Major State Basic Research Development Program of China (973 Program) (No.2011CB710600)
文摘The estimation of shear strength of rock mass discontinuity is always a focal, but difficult, problem in the field of geotechnical engineering. Considering the disadvantages and limitation of exist- ing estimation methods, a new approach based on the shadow area percentage （SAP） that can be used to quantify surface roughness is proposed in this article. Firstly, by the help of laser scanning technique, the three-dimensional model of the surface of rock discontinuity was established. Secondly, a light source was simulated, and there would be some shadows produced on the model surface. Thirdly, to obtain the value of SAP of each specimen, the shadow detection technique was introduced for use. Fourthly, compared with the result from direct shear testing and based on statistics, an empirical for- mula was found among SAP, normal stress, and shear strength. Data of Yujian （~ River were used as an example, and the following conclusions have been made. （1） In the case of equal normal stress, the peak shear stress is positively proportional to the SAP. （2） The formula for estimating was derived, and the predictions of peak-shear strength made with this equation well agreed with the experimental re- suits obtained in laboratory tests.
基金financially supported by the National Natural Science Foundation of China (Nos. 51971067 and 52001080)the Platform Research Capability Enhancement Project of Guangzhou University (No. 69-620939)R&D Program of Joint Institute of GZHU & ICoST (Nos. GI202107 and GI202109)。
文摘The effect of micro structure on the corrosion resistance of Al_(x)CoCrFeNiC_(0.01)(x=0.2,0.7,and 1.2)high-entropy alloys(HEAs) was systematically studied in this work.The microstructure evolution by regulating the Al content was analyzed in detail.Corrosion behavior was in situ monitored using the scanning vibration electrode technique,as well as some traditional electrochemical measurements.It is interesting to find that the compositions of body-centered cubic(bcc) and face-centered cubic(fcc)phases changed with the rising Al content,while the corresponding electrochemical responses for both phases were discriminated using the scanning Kelvin probe force microscopy method.Cr element was mainly distributed in the bcc phase for Al0.2(x=0.2) alloy,while its distribution changed to the fcc phase for the A10.7 and Al1.2alloys.The micro-galvanic corrosion cells formed between Cr-depleted and Cr-rich phases,resulting in the localized corrosion behaviors for the Al_(x)CoCrFeNiC_(0.01) HEAs,and the order for anti-corrosion property was Al0.2>Al1.2> Al0.7 HEAs.
基金Project supported by the National Key Research&Development Program of China(Grant Nos.2019YFA0308600 and 2020YFA0309000)the National Natural Science Foundation of China(Grant Nos.92365302,92065201,22325203,92265105,12074247,12174252,52102336)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)the Science and Technology Commission of Shanghai Municipality(Grant Nos.2019SHZDZX01,19JC1412701,20QA1405100,24LZ1401000,LZPY2024-04)financial support from the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302500)。
文摘Manipulating and braiding Majorana zero modes(MZM)are a critical step toward realizing topological quantum computing.The primary challenge is controlling the vortex,which hosts the MZM,within a superconducting film in a spatially precise manner.To address this,we developed a magnetic force-based vortex control technology using the STM system with a self-designed four-electrode piezo-scanner tube and investigated vortex manipulation on the NbSe_(2) superconducting film.We employed ferromagnetic tips to control the movement of vortex array induced by the tip's remanent magnetism.A magnetic core solenoid device was integrated into the STM system and a strong magnetic tip demagnetization technique was developed,providing a viable technical solution for further enabling single vortex manipulation.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60377016 and 60476020） and the National High Technology Development Program of China （Grant No 2002AA313070）.
文摘The third-order optical nonlinearities of [（CH3）4N]Au（dmit）2 （dmit = 4,5-dithiolate-1,3-dithiole-2-thione） at 532 nm and 1064 nm are investigated using the Z-scan technique with pulses of picoseconds duration. The Z-scan spectra reveal a strong nonlinear absorption （reverse saturable absorption） and a negative nonlinear refraction at 532 nm. No nonlinear absorption is observed at 1064 nm. The molecular second-order hyperpolarizability γ for the [（CH3）4N]Au（dmit）2 molecule at 532nm is estimated to be as high as （2.1 ±0.1） × 10^-31 esu, which is nearly three times larger than that at 1064 nm. The mechanism responsible for the difference between the results is analysed. Nonlinear transmission measurements suggest that this material has potential applications in optical limiting.
文摘Side channel attack may result in user key leakage as scan test techniques are applied for crypto-graphic chips. Many secure scan designs have been proposed to protect the user key. This paper meticulously selects three current scan test techniques, analyses their advantages and disadvantages and also compares them in security and area overhead. Users can choose one of them according to the requirements and further combination can be implemented to achieve better performance.
基金Project supported by the Ministry of Higher Education(Grant Nos.1-11-08-664FR/F1 and 01-0410-861FR)
文摘The nonlinear optical properties of a phosphate vitreous system [（ZnO）x-（MgO）30-x-（P2O5）70], where x=8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive （NLR） index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10-10 cm2·W-1. The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index （n2） and absorption coefficient （β） of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching.
文摘Z-scan technique is an effective tool for measuring the optical nonlinearity of the materials. By using this technique the measurement was made for total protein and albumin. The nonlinear refractive index of the total protein and albumin were found to vary linearly with concentration. Hence by calculating the nonlinear refractive index it is possible to measure their concentration in the sample. The values measured thus are found in equivalence with conventional colorimetric method.
文摘The third-order nonlinear optical properties of two dmit organometallic complexes, [(CH3)4N] [Au(C3S5)2] (MeAu) and [(CH3)4N][Ni(C3S5)2] (Me Ni) in acetone solutions, were characterized us- ing a short pulse Z-scan technique at 1064 nm wavelength. Self-defocusing effects were found in both samples and stronger saturable absorp-tion was observed in MeNi solution comparing with that of MeAu. The origins were analyzed for the differences between the results. Two figures of merit W and T were also calculated to evalu-ate the suitability of two materials for all-optical integrated devices. The results of W=22.84 and T≈0 of MeAu make it an excellent candidate for the all-optical applications.
文摘Background: The accuracy of the final prosthesis is affected by the final impression technique and master cast production. The aim of the present study was to evaluate the effect of the functional impression technique with various impression materials on the surface characteristic of dental stone casts and their clinical effect on the retention of complete dentures. Method: Specimens of three impression materials/stone casts were fabricated. The specimens of the impression materials/stone casts were divided into three equal groups (I, II, and III). The impression materials used were as follows: tissue conditioner group (I), zinc oxide (ZEO) (group II) and poly (vinyl siloxane) (PVS) (group III). Cylindrical split aluminium moulds were designed to receive the impression materials and the stone mixture. The surface roughness of the stone cast specimens of the three groups (I, II, and III) was measured with a surface profilometer and analyzed by a scanning electron microscope. A clinical study included five severely resorbed mandibular edentulous alveolar ridges and edentulous maxillary arches. Each subject received three heat-cured acrylic resin dentures, fabricated using the functional impression technique. The three dentures were identical except for the different impression materials used from Groups I, II and III. The retentive force of each denture for each subject was measured. Result: The results of this study revealed that the mean value of surface roughness of the stone cast surface of group I was higher than group II and group III. A statistically significant difference was observed in surface roughness and the retentive dislodging force between the three studied groups. Although using a tissue conditioner as a functional impression material led to a high level of surface roughness and good retention, it could not produce the same smooth surface quality of PVS or ZEO. These data were supported by SEM analysis. The complete dentures for these patients require important oral and denture hygiene care. Conclusion: Complete dentures made using functional impression technique with PVC as a final impression material are more comfortable, retentive and stable.
基金Supported by Zhuhai Medical Research Fund,No.ZH3310200001PJL.
文摘BACKGROUND Coronary computed tomography angiography(CCTA)is the preferred noninvasive examination method for coronary heart disease.However,the radiation from computed tomography has become a concern since public awareness of radiation hazards continue to increase.AIM To explore the value of multiple dose reduction techniques for CCTA.METHODS Consecutive normal and overweight patients were prospectively divided into two groups:Group A1,patients who received multiple dose reduction scans(n=82);and group A2,patients who received conventional scans(n=39).The scan parameters for group A1 were as follows:Isocentric scan,tube voltage=80 kV,and tube current control using 80%smart milliampere.The scan parameters for group A2 were as follows:Normal position,tube voltage=100 kV,and smart milliampere.RESULTS The average effective doses(EDs)for groups A1 and A2 were 1.13±0.35 and 3.36±1.30 mSv,respectively.There was a statistically significant difference in ED between the two groups(P<0.01).Furthermore,noise was significantly lower,and both signal-to-noise ratio and contrast signal-to-noise ratio were higher in group A2 when compared to group A1(P<0.01).Moreover,the subjective image quality(IQ)scores were excellent in both groups,in which there was no significant difference in subjective IQ score between the two groups(P=0.12).CONCLUSION Multiple dose reduction scan techniques can significantly decrease the ED of patients receiving CCTA examinations for clinical diagnosis.
基金Supported by Project of National Natural Science Foundation of Shandong Province(ZR2015PH015)
文摘[Objectives]To study the immediate-release mechanism of dehydrotrametenolic acid and dehydroeburicoic acid in Poriae Cutis total triterpenoids tablets by liquid-solid compacts technique.[Methods] Taking dehydrotrametenolic acid and dehydroeburicoic acid as indicators,differences in dissolution were compared between liquid-solid compressed tablets and crude drug of total triterpenoids in Poriae Cutis;crude drug,powder of liquid-solid compressed tablets and excipients of liquid-solid compressed tablets were characterized by differential scanning calorimetry( DSC).[Results]Liquid-solid compact technique could significantly improve dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid. The total dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid in Poriae Cutis total triterpenoids tablets was 92%,t50( time for 50% total dissolution rate) and t_D( time for 63. 2% total dissolution rate) were 11. 18 min and 22. 71 min; the total dissolution rate of dehydrotrametenolic acid and dehydroeburicoic acid in crude drug of total triterpenoids was 29%,and t50 and t_D were231. 06 min and 359. 23 min. DSC showed that there was no mutual interaction between excipients and total triterpenoids in Poriae Cutis; on the DSC curve for powder of liquid-solid compressed tablets,the absorption peak vanished completely,indicating that the drug exists in the amorphous form in the liquid-solid powder.[Conclusions] Liquid-solid compact technique can increase the dissolution rate of total triterpenoids in Poriae Cutis and allow rapid release of poorly water soluble drugs.
基金supported by the National Natural Science Foundation of China,No.32171356(to YW)Self-Support Research Projects of Shihezi University,No.ZZZC2021105(to WJ)+1 种基金Capital Medical University Natural Science Cultivation Fund,No.PYZ23044(to FQM)Beijing Municipal Natural Science Foundation,No.7244410(to JHD)。
文摘Previous research has demonstrated the feasibility of repairing nerve defects through acellular allogeneic nerve grafting with bone marrow mesenchymal stem cells.However,adult tissue–derived mesenchymal stem cells encounter various obstacles,including limited tissue sources,invasive acquisition methods,cellular heterogeneity,purification challenges,cellular senescence,and diminished pluripotency and proliferation over successive passages.In this study,we used induced pluripotent stem cell-derived mesenchymal stem cells,known for their self-renewal capacity,multilineage differentiation potential,and immunomodulatory characteristics.We used induced pluripotent stem cell-derived mesenchymal stem cells in conjunction with acellular nerve allografts to address a 10 mm-long defect in a rat model of sciatic nerve injury.Our findings reveal that induced pluripotent stem cell-derived mesenchymal stem cells exhibit survival for up to 17 days in a rat model of peripheral nerve injury with acellular nerve allograft transplantation.Furthermore,the combination of acellular nerve allograft and induced pluripotent stem cell-derived mesenchymal stem cells significantly accelerates the regeneration of injured axons and improves behavioral function recovery in rats.Additionally,our in vivo and in vitro experiments indicate that induced pluripotent stem cell-derived mesenchymal stem cells play a pivotal role in promoting neovascularization.Collectively,our results suggest the potential of acellular nerve allografts with induced pluripotent stem cell-derived mesenchymal stem cells to augment nerve regeneration in rats,offering promising therapeutic strategies for clinical translation.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50275039)the Scientific Research Foundation of Harbin Institute of Technology(HIT2002.23).
文摘To resolve inflation of inertial confinement fusion (ICF) target and encapsulation of micro inflation hole with adhesive, a scanning probe microscope (SPM) diamond microprobe was used as the cutting tool with SPM in contact mode. Some parameters influencing the quality of micro inflation hole, such as the scanning direction of the diamond tip, the scanning rate and the contact force are discussed. Accurate taper hole was achieved whose climension and precision could meet the requirements of inflation and encapsulation technique of micro hole. The experimental results show that using SPM diamond microprobe as the cutting tool and with special processing technique, the precision machining of target capsule's taper inflation hole can be realized. A novel operative technology for filling high Z gas to target is provided.
文摘A novel procedure to calibrate the scanning line-structured laser sensor is presented. A drone composed of two orthogonal planes is designed, with the result that camera parameters and light-plane equation parameters is achieved simultaneously.
基金supported by the Shenzhen Basic Research Project of Science and Technology under Grant No.JCYJ20120613112423982
文摘In conventional pulsed laser deposition （PLD） technique, plume deflection and composition distribution change with the laser incident direction and pulse energy, then causing uneven film thickness and composition distribution for a multicomponent film and eventually leading to low device quality and low rate of final products. We present a novel method based on PLD for depositing large CIGS films with uni- form thickness and stoichiometry. By oscillating a mirror placed coaxially with the incident laser beam, the laser＇s focus is scanned across the rotating target surface. This arrangement maintains a constant re- flectance and optical distance, ensuring that a consistent energy density is delivered to the target surface by each laser pulse. Scanning the laser spot across the target suppresses the formation of micro-columns, and thus the plume deflection effect that reduces film uniformity in conventional PLD technique is eliminated. This coaxial scanning PLD method is used to deposit a CIGS film, 500 nm thick, with thickness uniformity exceeding ±3% within a 5 cm diameter, and exhibiting a highly homogeneous elemental distribution.
