The transport of ablated particles produced by single pulsed-laser ablation is simulated via Monte Carlo method. The pressure ranges of velocity splitting of ablated particles in different inert gases are investigated...The transport of ablated particles produced by single pulsed-laser ablation is simulated via Monte Carlo method. The pressure ranges of velocity splitting of ablated particles in different inert gases are investigated. The result shows that the range of velocity splitting decreases with the atomic mass of the ambient gas increasing. The ambient gas whose atomic mass is more than that of Kr cannot induce the velocity splitting of ablated particles. The results are explained by the underdamping model and the inertia flow model.展开更多
A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a l...A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a low pressure inert gas.The ablated-particle density and velocity distributions are analyzed.The force distributions acting on the ablated particles are investigated.The influence of the substrate on the ablated-particle velocity distribution and the force distribution acting on the ablated particles are discussed.The Monte Carlo simulation results approximately agree with the experimental data at the pressure of 8 Pa to 17 Pa.This is helpful to investigate the gas phase nucleation and growth mechanism of nanoparticles.展开更多
The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled wi...The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled with the radiation hydrodynamic code MULTI1D in this study.Using the code,the slowing-down process and ablation process of the hot electron beam are simulated.The ablation pressure scaling law of hot electron beam is confirmed in our simulations.The hot electron transport is simulated in the radiation-ablated plasmas relevant to indirect-drive ICF,where the spatial profile of hot electron energy deposition is presented around the shock compressed region.It is shown that the hot electron can prominently increase the total ablation pressure in the early phase of radiation-ablated plasma.So,our study suggests that a potential-driven symmetric mechanism may occur under the irradiation of asymmetric hot electron beam.The possible degradation from the hot electron transport and preheating is also discussed.展开更多
AIM:To investigate whether tumor debris created by high-intensity focused ultrasound(HIFU)could trigger antitumor immunity in a mouse hepatocellular carcinoma model. METHODS:Twenty C57BL/6J mice bearing H22 hepatocell...AIM:To investigate whether tumor debris created by high-intensity focused ultrasound(HIFU)could trigger antitumor immunity in a mouse hepatocellular carcinoma model. METHODS:Twenty C57BL/6J mice bearing H22 hepatocellular carcinoma were used to generate antitumor vaccines.Ten mice underwent HIFU ablation,and the remaining 10 mice received a sham-HIFU procedure with no ultrasound irradiation.Sixty normal mice were randomly divided into HIFU vaccine,tumor vaccine and control groups.These mice were immunized with HIFU-generated vaccine,tumor-generated vaccine,and saline,respectively.In addition,20 mice bearing H22 tumors were successfully treated with HIFU ablation. The protective immunity of the vaccinated mice was investigated before and after a subsequent H22 tumor challenge.Using the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay,the cytotoxicity of splenic lymphocytes co-cultured with H22 cells wasdetermined in vitro before the tumor challenge,and tumor volume and survival were measured in vivo after the challenge in each group.The mechanism was also explored by loading the vaccines with bone marrowderived dendritic cells(DCs). RESULTS:Compared to the control,HIFU therapy, tumor-generated and HIFU-generated vaccines significantly increased cytolytic activity against H22 cells in the splenocytes of the vaccinated mice(P<0.001). The tumor volume was significantly smaller in the HIFU vaccine group than in the tumor vaccine group(P <0.05)and control group(P<0.01).However,there was no tumor growth after H22 rechallenge in the HIFU therapy group.Forty-eight-day survival rate was 100%in mice in the HIFU therapy group,30%in both the HIFU vaccine and tumor vaccine groups,and 20% in the control group,indicating that the HIFU-treated mice displayed significantly longer survival than the vaccinated mice in the remaining three groups(P< 0.001).After bone marrow-derived DCs were incubated with HIFU-generated and tumor-generated vaccines, the number of mature DCs expressing MHC-Ⅱ + ,CD80 + and CD86 + molecules was significantly increased,and interleukin-12 and interferon-γlevels were significantly higher in the supernatants when compared with immature DCs incubated with mouse serum(P<0.001). However,no differences of the number of mature DCs and cytokine levels were observed between the HIFU- generated and tumor-generated vaccines(P>0.05). CONCLUSION:Tumor debris remaining after HIFU can improve tumor immunogenicity.This debris releases tumor antigens as an effective vaccine to develop host antitumor immune response after HIFU ablation.展开更多
Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are ur...Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are urgent.Here,another 2D material,violet phosphorus(VP)nanoflake is investigated as gas sensing material.The VP nanoflakes have been effectively ablated to have layers of 1–5 layers by laser ablation in glycol.The VP nanoflakes are combined with graphene to form VP/G heterostructuresbased NO sensor.An ultra-high gauge factor of 3×10^(7)for ppb-level sensing and high resistance response of 59.21%with ultra-short recovery time of 6s for ppm-level sensing have been obtained.The sensing mechanism is also analysed by density functional theory(DFT)calculations.The adsorption energy of VP/G is calculated to be-0.788 e V,resulting in electrons migration from P to N to form a P-N bond in the gap between VP and graphene sheet.This work provides a facile approach to ablate VP for mass production.The as-produced structures have also provided potential gas sensors with ultrasensitive performance as ppb-level room-temperature sensors.展开更多
The emission spectrum of AlO radicals was analyzed in 440-540 nm in the reaction of laser ablated Al beam and O 2. The carrier of spectrum was assigned to Δ ν =0, ±1, ±2 vibrational sequences of B ...The emission spectrum of AlO radicals was analyzed in 440-540 nm in the reaction of laser ablated Al beam and O 2. The carrier of spectrum was assigned to Δ ν =0, ±1, ±2 vibrational sequences of B 2Σ +-X 2Σ + transition of AlO radicals, the observed maximum vibrational quantum number was ν ′=6. The rotational and vibrational temperatures of B state were estimated at 3000 and 7500 K by spectrally simulating the rovibronic population distribution. There is a strong evidence that the production of excited Al( 2 S ) atoms is essential to the formation of excited AlO radicals.展开更多
Low energy metallic ions, generated by a Q-switched Nd：YAG laser （1064-nm wavelength, 10-mJ energy, 9-nm 12-ns-pulse width, 1011 W/cm2 intensity） irradiated on a silicon substrate to modify various properties, such...Low energy metallic ions, generated by a Q-switched Nd：YAG laser （1064-nm wavelength, 10-mJ energy, 9-nm 12-ns-pulse width, 1011 W/cm2 intensity） irradiated on a silicon substrate to modify various properties, such as electrical, morphological, and structural modifications. Thomson parabola technique is used to calculate the energy of these metallic ions whereas the electrical conductivity is calculated with the help of Four-point probe. Interestingly circular tracks forming chain like damage trails are produced via these energetic ions which are carefully examined by optical microscopy. It is observed that excitation, ionization, and cascade collisions are responsible for surface modifications of irradiated samples. Four-point probe analysis revealed that the electrical conductivity of substrate has reduced with increasing trend of atomic number of irradiated metallic ions （A1, Ti, Cu, and Au）. The x-ray diffraction analysis elucidated the crystallographic changes leading to reduction of grain size of N-type silicon substrate, which is also associated with the metallic ions used. The decreasing trend of conductivity and grain size is due to thermal stresses, scattering effect, structural imperfections, and non-uniform conduction of energy absorbed by substrate atoms after the ion irradiation.展开更多
Laser ablated high temperature superconducting and related thin films are investigated with a microscopical point of view.The microstructure and microchemistry of three thin films(Y-Ba-Cu-O, Bi-Pb-Sr-Ca-Cu-O and Sr-Ca...Laser ablated high temperature superconducting and related thin films are investigated with a microscopical point of view.The microstructure and microchemistry of three thin films(Y-Ba-Cu-O, Bi-Pb-Sr-Ca-Cu-O and Sr-Ca-Cu-O)are demonstrated as examples of laser ablation products.展开更多
Thermal characteristics of tightly-contacted copper-gold double-layer thin film target under ablation of femtosec- ond laser pulses are investigated by using a two-temperature theoretical model. Numerical simulation s...Thermal characteristics of tightly-contacted copper-gold double-layer thin film target under ablation of femtosec- ond laser pulses are investigated by using a two-temperature theoretical model. Numerical simulation shows that electron heat flux varies significantly on the boundary of copper-gold film with different maximal electron temperature of 1.15 x 103 K at 5 ps after ablating laser pulse in gold and copper films, which can reach a balance around 12.6 ps and 8.2 ps for a single and double pulse ablation, respectively, and in the meantime, the lattice temperature difference crossing the gold-copper interface is only about 0.04×103 K at the same time scale. It is also found that electron-lattice heat relaxation time increases linearly with laser fluence in both single and double pulse ablation, and a sudden change of the relaxation time appears after the laser energy density exceeds the ablation threshold.展开更多
Al-doped ZnO（AZO） thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures（P_（O2））.The effect of P_（O2） on the crystal structure,preferred orientation as well a...Al-doped ZnO（AZO） thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures（P_（O2））.The effect of P_（O2） on the crystal structure,preferred orientation as well as the electrical and optical properties of the films was investigated.The structure characterizations indicated that the as-grown films were single-phased with a wurtzite ZnO structure,showing a significant c-axis orientation.The films were well crystallized and exhibited better crystallinity and denser texture when deposited at higher P_（O2）.At the optimum oxygen partial pressures of 10- 15 Pa,the AZO thin films were epitaxially grown on c-sapphire substrates with the（0001） plane parallel to the substrate surface,i e,the epitaxial relationship was AZO（000 1） // A1_2O_3（000 1）.With increasing P_（O2）,the value of Hall carrier mobility was increased remarkably while that of carrier concentration was decreased slightly,which led to an enhancement in electrical conductivity of the AZO thin films.All the films were highly transparent with an optical transmittance higher than 85%.展开更多
Flexible triboelectric nanogenerators (TENGs)-based pressure sensors are very essential for the wide-range applications, comprising wearable healthcare systems, intuitive human-device interfaces, electronic-skin (e-sk...Flexible triboelectric nanogenerators (TENGs)-based pressure sensors are very essential for the wide-range applications, comprising wearable healthcare systems, intuitive human-device interfaces, electronic-skin (e-skin), and artificial intelligence. Most of conventional fabrication methods used to produce high-performance TENGs involve plasma treatment, photolithography, printing, and electro-deposition. However, these fabrication techniques are expensive, multi-step, time-consuming and not suitable for mass production, which are the main barriers for efficient and cost-effective commercialization of TENGs. Here, we established a highly reliable scheme for the fabrication of a novel eco-friendly, low cost, and TENG-based pressure sensor (TEPS) designed for usage in self-powered-human gesture detection (SP-HGD) likewise wearable healthcare applications. The sensors with microstructured electrodes performed well with high sensitivity (7.697 kPa^-1), a lower limit of detection (~ 1 Pa), faster response time (< 9.9 ms), and highly stable over > 4,000 compression-releasing cycles. The proposed method is suitable for the adaptable fabrication of TEPS at an extremely low cost with possible applications in self-powered systems, especially e-skin and healthcare applications.展开更多
Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,repr...Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,reproductive performance were recorded and IFN-γ concentrations in heart,lung,liver,spleen,kidney and serum were quantified by ELISA. There were no significant differences of IFN-γ in heart,lung and kidney between 4 strains although control group was higher.It was observed that for IL-12^(-/-) mice,compared with other 3 groups,IFN-γ in liver and spleen were decreased(p<0.05)and reproductive performance appeared to be impaired.Serum IFN-γ level of IL-12^(-/-)/18^(-/-) mice was significantly higher(p<0.05).It was showed that IFN-γ productions under the normal condition were independent upon IL-12 and IL-18,its expressions in various tissues were different,and optimal IFN-γ is necessary for the normal growth and development of mammals.This study is helpful for clinical cytokines therapy.Cellular & Molecular Immunology.2005;2(1):68-72.展开更多
Radiofrequency ablation(RFA),particularly endoscopic ultrasound-guided RFA(EUS-RFA),has emerged as a promising minimally invasive approach for the treatment of pancreatic cancer,especially in patients with locally adv...Radiofrequency ablation(RFA),particularly endoscopic ultrasound-guided RFA(EUS-RFA),has emerged as a promising minimally invasive approach for the treatment of pancreatic cancer,especially in patients with locally advanced or unresectable disease.This review outlines recent technological developments in EUS-RFA,including innovations in energy delivery systems,probe design,and real-time thermal monitoring,which have improved the precision and safety of the procedure.Clinical studies combining EUS-RFA with chemotherapy have demonstrated encouraging outcomes,with improvements in overall survival,progression-free survival,tumor necrosis,and symptom control compared to chemotherapy alone.Additionally,RFA-induced tumor antigen release and modulation of the tumor microenvironment suggest a potential synergistic role with immunotherapy.Despite its promise,the widespread adoption of EUS-RFA is limited by a lack of large-scale randomized controlled trials and standardized treatment protocols.展开更多
BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two...BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two techniques in treatment-naive HCC.AIM To compare the risk of local tumor progression(LTP)according to the technique;secondary endpoints included technique efficacy rate at one-month,overall survival and major complication rate.METHODS A bi-institutional retrospective analysis of patients undergoing treatment-naive HCC ablation by either technique was performed.Inverse probability of treatment weighting was used to compare the two groups.Mixed effects multivariate Cox regression was applied to identify risk factors for LTP.RESULTS A total of 362 patients(mean age,66.1±6.2 years,308 men)were included,of which 242(323 tumors)treated by mbp-RFA and 120(168 tumors)by MWA.After a median follow-up of 27 months,cumulative LTP was 11.4%after mbp-RFA and 25.2%after MWA.Independent risk factors for LTP at multivariate analysis were MWA(hazard ratio=2.85,P<0.001)and tumor size(hazard ratio=1.08,P<0.001).Two-year LTP-free survival was higher after mbp-RFA than MWA regardless of size(<3 cm:96%vs 87.1%,P<0.01;≥3 cm:87.5%vs 74%,P=0.04).Technique efficacy rate was higher after mbp-RFA(94.1%vs 87.5%,P=0.01).No difference was observed in major complication rate(9.5%vs 7.5%,P=0.59),nor 5-year overall survival(63.6%vs 58.3%,P=0.33).CONCLUSION Mbp-RFA leads to better local tumor control of treatment-naïve HCC than MWA regardless of tumor size and has better primary efficacy,while maintaining a comparable safety profile.展开更多
Colorectal cancer(CRC)with lung oligometastases,particularly in the presence of extrapulmonary disease,poses considerable therapeutic challenges in clinical practice.We have carefully studied the multicenter study by ...Colorectal cancer(CRC)with lung oligometastases,particularly in the presence of extrapulmonary disease,poses considerable therapeutic challenges in clinical practice.We have carefully studied the multicenter study by Hu et al,which evaluated the survival outcomes of patients with metastatic CRC who received image-guided thermal ablation(IGTA).These findings provide valuable clinical evidence supporting IGTA as a feasible,minimally invasive approach and underscore the prognostic significance of metastatic distribution.However,the study by Hu et al has several limitations,including that not all pulmonary lesions were pathologically confirmed,postoperative follow-up mainly relied on dynamic contrast-enhanced computed tomography,no comparative analysis was performed with other local treatments,and the impact of other imaging features on efficacy and prognosis was not evaluated.Future studies should include complete pathological confirmation,integrate functional imaging and radiomics,and use prospective multicenter collaboration to optimize patient selection standards for IGTA treatment,strengthen its clinical evidence base,and ultimately promote individualized decision-making for patients with metastatic CRC.展开更多
Over the past ten years,numerous papers have been published on the use of indocyanine green(ICG)fluorescence in liver surgery for hepatocellular carcinoma(HCC).There are many different applications.The first involves ...Over the past ten years,numerous papers have been published on the use of indocyanine green(ICG)fluorescence in liver surgery for hepatocellular carcinoma(HCC).There are many different applications.The first involves targeting superficial tumors in patients with macronodular cirrhosis and an irregular liver surface.In a minimally invasive setting,the lack of tactile feedback on the hepatic surface makes detecting subcapsular HCC with ultrasound alone challenging.ICG fusion images can mimic the tactile feedback of the hand and act as an ultrasound booster.ICG fluorescence can be used to evaluate tumor residues after minimally invasive thermal ablation.ICG fluorescence imaging can also be used to identify the grade of HCC early on and evaluate the microinvasive component.展开更多
Laser ablation in liquids has emerged as a new branch of nanoscience for developing various nanomaterials with different shapes.However, how to design and control nanomaterial growth is still a challenge due to the un...Laser ablation in liquids has emerged as a new branch of nanoscience for developing various nanomaterials with different shapes.However, how to design and control nanomaterial growth is still a challenge due to the unique chemical-physical process chain correlated with nanomaterial nucleation and growth, including plasma phase(generation and rapid quenching), gas(bubble) phase,and liquid phase. In this review, through summarizing the literature about this topic and comparing with the well-established particle growth mechanisms of the conventional wet chemistry technique, our perspective on the possible nanoparticle growth mechanisms or routes is presented, aiming at shedding light on how laser-ablated particles grow in liquids. From the microscopic viewpoint, the nanoparticle growth contains six mechanisms, including LaMer-like growth, coalescence, Ostwald ripening, particle(oriented) attachment, adsorbate-induced growth and reaction-induced growth. For each microscopic growth mechanism, the vivid growth scenes of some representative nanomaterials recorded by TEM and SEM measurements are displayed. Afterwards,the scenes from the macroscopic viewpoint for the large submicro-and micro-scale nanospheres and anisotropic nanostructures formation and evolution from one nanostructure into another one are presented. The panorama of how diverse nanomaterials grow during and after laser ablation in liquids shown in this review is intended to offer a overview for researchers to search for the possible mechanisms correlated to their synthesized nanomaterials, and more expectation is desired to better design and tailor the morphology of the nanocrystals synthesized by LAL technique.展开更多
Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 m...Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 mm^(3))and medium distant(100 mm^(3))EG7 lymphomas engineered to express ovalbumin(OVA)as a nominal tumor antigen.We established experimental protocols including IRE alone and IRE combined with Toll-like receptor(TLR)3/9 agonists(poly I:C/CpG)(IRE+pIC/CpG),PD-1 blockade(IRE+PD-1 blockade),or both(IRE+Combo)to investigate therapeutic effects on primary and distant EG7 tumors and conversion-promoting effects on the immunotolerant tumor microenvironment(TME).We demonstrated that IRE alone simulated very weak OVA-specific CD8^(+)T cell responses and did not inhibit primary tumor growth.IRE+pIC/CpG synergistically stimulated more efficient OVA-specific CD8^(+)T cell responses and primary tumor growth inhibition than IRE+PD-1 blockade.IRE+pIC/CpG played a major role in the modulation of immune cell profiles but a minor role in the downregulation of PD-L1 expression in the TME and vice versa for IRE+PD-1 blockade.IRE+Combo cooperatively induced potent OVA-specific CD8^(+)T cell immunity and rescued exhausted intratumoral CD8^(+)T cells,leading to eradication of not only primary tumors but also untreated concomitant distant tumors and lung metastases.IRE+Combo efficiently modulated immune cell profiles,as evidenced by reductions in immunotolerant type-2(M2)macrophages,myeloid-derived suppressor-cells,plasmacytoid dendritic cells,and regulatory T cells and by increases in immunogenic M1 macrophages,CD169^(+)macrophages,type-1 conventional dendritic cells,and CD8^(+)T cells,leading to conversion of immunotolerance in not only primary TMEs but also untreated distant TMEs.IRE+Combo also showed effective therapeutic effects in two breast cancer models.Therefore,our results suggest that IRE+Combo is a promising strategy to improve IRE ablation therapy in cancer.展开更多
Mass, velocity and angle distributions of the ablated species generated from 355 nm pulsed laser ablation of a LiMn2O4 target were investigated with an angle- and time-resolved mass spectrometric technique. Both neutr...Mass, velocity and angle distributions of the ablated species generated from 355 nm pulsed laser ablation of a LiMn2O4 target were investigated with an angle- and time-resolved mass spectrometric technique. Both neutral and ionic species of Li, O, LiO, LiO2, Mn, Li2, Li4, Li6, LiMn, MnO and MnO2 were observed at the laser fluence of 0.8 J · cm-2. The yield and variety of the ablated species increase with increasing the laser fluence. The time-of-flight spectra of ablated species can be fitted by a Maxwell-Boltzmann distribution with a center-of-mass velocity. There exist laser fluence thresholds for the ablated LiMn, Li2O and LiO2 species, and the fluence threshold of ionic species is higher than that of neutral species. The angular distributions of the ionic and neutral ablated species can be simulated by a cosηθ or a bicosine function α cosθ + (1-α) cosηθ. In addition, the ablation mechanism of LiMn2O4 by a 355 nm pulsed laser is discussed.展开更多
The gas phase reactions of metal plasma with alcohol clusters were studied by time of flight mass spectrometry （TOFMS） using laser ablation-molecular beam （LAMB） method. The significant dependence of the product c...The gas phase reactions of metal plasma with alcohol clusters were studied by time of flight mass spectrometry （TOFMS） using laser ablation-molecular beam （LAMB） method. The significant dependence of the product cluster ions on the molecular beam conditions was observed. When the plasma acted on the low density parts of the pulsed molecular beam, the metal-alcohol complexes M^＋An （M=Cu, Al, Mg, Ni and A=C2H5OH, CH3OH） were the dominant products, and the sizes of product ion clusters were smaller. While the plasma acted on the high density part of the beam, however, the main products turned to be protonated alcohol clusters H^＋An and, as the reactions of plasma with methanol were concerned, the protonated water-methanol complexes H3O^＋（CH3OH）n with a larger size （n≤12 for ethanol and n≤24 for methanol）. Similarly, as the pressure of the carrier helium gas was varied from 1 × 10^5 to 5 × 10^5 Pa, the main products were changed from M^＋An to H^＋An and the sizes of the clusters also increased. The changes in the product clusters were attributed to the different formation mechanism of the output ions, that is, the M^＋An ions came from the reaction of metal ion with alcohol clusters, while H^＋An mainly from collisional reaction of electron with alcohol clusters.展开更多
基金supported by the National Basic Research Program of China(Grant No.2011CB612305)the Natural Science Foundation of Hebei Province,China(Grant Nos.E2012201035 and E2011201134)
文摘The transport of ablated particles produced by single pulsed-laser ablation is simulated via Monte Carlo method. The pressure ranges of velocity splitting of ablated particles in different inert gases are investigated. The result shows that the range of velocity splitting decreases with the atomic mass of the ambient gas increasing. The ambient gas whose atomic mass is more than that of Kr cannot induce the velocity splitting of ablated particles. The results are explained by the underdamping model and the inertia flow model.
基金supported by the Natural Science Foundation of Hebei Province,China(No.A2015201166)the Natural Science Foundation of Hebei University,China(No.2013-252)
文摘A Monte Carlo simulation method with an instantaneous density dependent meanfree-path of the ablated particles and the Ar gas is developed for investigating the transport dynamics of the laser-ablated particles in a low pressure inert gas.The ablated-particle density and velocity distributions are analyzed.The force distributions acting on the ablated particles are investigated.The influence of the substrate on the ablated-particle velocity distribution and the force distribution acting on the ablated particles are discussed.The Monte Carlo simulation results approximately agree with the experimental data at the pressure of 8 Pa to 17 Pa.This is helpful to investigate the gas phase nucleation and growth mechanism of nanoparticles.
基金Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA25050600)the DCI joint team。
文摘The transport of hot electrons in inertial confinement fusion(ICF)is integrated issue due to the coupling of hydrodynamic evolution and many physical processes.A hot electron transport code is developed and coupled with the radiation hydrodynamic code MULTI1D in this study.Using the code,the slowing-down process and ablation process of the hot electron beam are simulated.The ablation pressure scaling law of hot electron beam is confirmed in our simulations.The hot electron transport is simulated in the radiation-ablated plasmas relevant to indirect-drive ICF,where the spatial profile of hot electron energy deposition is presented around the shock compressed region.It is shown that the hot electron can prominently increase the total ablation pressure in the early phase of radiation-ablated plasma.So,our study suggests that a potential-driven symmetric mechanism may occur under the irradiation of asymmetric hot electron beam.The possible degradation from the hot electron transport and preheating is also discussed.
基金Supported by The Foundation of Ministry of Education of China,No.IRT0454
文摘AIM:To investigate whether tumor debris created by high-intensity focused ultrasound(HIFU)could trigger antitumor immunity in a mouse hepatocellular carcinoma model. METHODS:Twenty C57BL/6J mice bearing H22 hepatocellular carcinoma were used to generate antitumor vaccines.Ten mice underwent HIFU ablation,and the remaining 10 mice received a sham-HIFU procedure with no ultrasound irradiation.Sixty normal mice were randomly divided into HIFU vaccine,tumor vaccine and control groups.These mice were immunized with HIFU-generated vaccine,tumor-generated vaccine,and saline,respectively.In addition,20 mice bearing H22 tumors were successfully treated with HIFU ablation. The protective immunity of the vaccinated mice was investigated before and after a subsequent H22 tumor challenge.Using the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide assay,the cytotoxicity of splenic lymphocytes co-cultured with H22 cells wasdetermined in vitro before the tumor challenge,and tumor volume and survival were measured in vivo after the challenge in each group.The mechanism was also explored by loading the vaccines with bone marrowderived dendritic cells(DCs). RESULTS:Compared to the control,HIFU therapy, tumor-generated and HIFU-generated vaccines significantly increased cytolytic activity against H22 cells in the splenocytes of the vaccinated mice(P<0.001). The tumor volume was significantly smaller in the HIFU vaccine group than in the tumor vaccine group(P <0.05)and control group(P<0.01).However,there was no tumor growth after H22 rechallenge in the HIFU therapy group.Forty-eight-day survival rate was 100%in mice in the HIFU therapy group,30%in both the HIFU vaccine and tumor vaccine groups,and 20% in the control group,indicating that the HIFU-treated mice displayed significantly longer survival than the vaccinated mice in the remaining three groups(P< 0.001).After bone marrow-derived DCs were incubated with HIFU-generated and tumor-generated vaccines, the number of mature DCs expressing MHC-Ⅱ + ,CD80 + and CD86 + molecules was significantly increased,and interleukin-12 and interferon-γlevels were significantly higher in the supernatants when compared with immature DCs incubated with mouse serum(P<0.001). However,no differences of the number of mature DCs and cytokine levels were observed between the HIFU- generated and tumor-generated vaccines(P>0.05). CONCLUSION:Tumor debris remaining after HIFU can improve tumor immunogenicity.This debris releases tumor antigens as an effective vaccine to develop host antitumor immune response after HIFU ablation.
基金the funding support by National Natural Science Foundation of China(Nos.61705125,22175136)Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Guangxi University(No.2022GXYSOF15)。
文摘Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are urgent.Here,another 2D material,violet phosphorus(VP)nanoflake is investigated as gas sensing material.The VP nanoflakes have been effectively ablated to have layers of 1–5 layers by laser ablation in glycol.The VP nanoflakes are combined with graphene to form VP/G heterostructuresbased NO sensor.An ultra-high gauge factor of 3×10^(7)for ppb-level sensing and high resistance response of 59.21%with ultra-short recovery time of 6s for ppm-level sensing have been obtained.The sensing mechanism is also analysed by density functional theory(DFT)calculations.The adsorption energy of VP/G is calculated to be-0.788 e V,resulting in electrons migration from P to N to form a P-N bond in the gap between VP and graphene sheet.This work provides a facile approach to ablate VP for mass production.The as-produced structures have also provided potential gas sensors with ultrasensitive performance as ppb-level room-temperature sensors.
基金Supported by the National Natural Science Foundation of China( No.2 0 0 730 4 2 )
文摘The emission spectrum of AlO radicals was analyzed in 440-540 nm in the reaction of laser ablated Al beam and O 2. The carrier of spectrum was assigned to Δ ν =0, ±1, ±2 vibrational sequences of B 2Σ +-X 2Σ + transition of AlO radicals, the observed maximum vibrational quantum number was ν ′=6. The rotational and vibrational temperatures of B state were estimated at 3000 and 7500 K by spectrally simulating the rovibronic population distribution. There is a strong evidence that the production of excited Al( 2 S ) atoms is essential to the formation of excited AlO radicals.
文摘Low energy metallic ions, generated by a Q-switched Nd：YAG laser （1064-nm wavelength, 10-mJ energy, 9-nm 12-ns-pulse width, 1011 W/cm2 intensity） irradiated on a silicon substrate to modify various properties, such as electrical, morphological, and structural modifications. Thomson parabola technique is used to calculate the energy of these metallic ions whereas the electrical conductivity is calculated with the help of Four-point probe. Interestingly circular tracks forming chain like damage trails are produced via these energetic ions which are carefully examined by optical microscopy. It is observed that excitation, ionization, and cascade collisions are responsible for surface modifications of irradiated samples. Four-point probe analysis revealed that the electrical conductivity of substrate has reduced with increasing trend of atomic number of irradiated metallic ions （A1, Ti, Cu, and Au）. The x-ray diffraction analysis elucidated the crystallographic changes leading to reduction of grain size of N-type silicon substrate, which is also associated with the metallic ions used. The decreasing trend of conductivity and grain size is due to thermal stresses, scattering effect, structural imperfections, and non-uniform conduction of energy absorbed by substrate atoms after the ion irradiation.
文摘Laser ablated high temperature superconducting and related thin films are investigated with a microscopical point of view.The microstructure and microchemistry of three thin films(Y-Ba-Cu-O, Bi-Pb-Sr-Ca-Cu-O and Sr-Ca-Cu-O)are demonstrated as examples of laser ablation products.
基金supported by the National Natural Science Foundation of China (Grant No. 60978014)the Natural Science Foundation of Jilin Province (Grant No. 20090523)the Educational Commission of Jilin Province (Grant No. [2008]297)
文摘Thermal characteristics of tightly-contacted copper-gold double-layer thin film target under ablation of femtosec- ond laser pulses are investigated by using a two-temperature theoretical model. Numerical simulation shows that electron heat flux varies significantly on the boundary of copper-gold film with different maximal electron temperature of 1.15 x 103 K at 5 ps after ablating laser pulse in gold and copper films, which can reach a balance around 12.6 ps and 8.2 ps for a single and double pulse ablation, respectively, and in the meantime, the lattice temperature difference crossing the gold-copper interface is only about 0.04×103 K at the same time scale. It is also found that electron-lattice heat relaxation time increases linearly with laser fluence in both single and double pulse ablation, and a sudden change of the relaxation time appears after the laser energy density exceeds the ablation threshold.
基金Funded by National Natural Science Foundation of China(Nos.51272195,51521001)111 project(No.B13035)+1 种基金Hubei Provincial National Natural Science Foundation(No.2015CFB724)Fundamental Research Funds for the Central Universities(Nos.2013-ZD-4,2014-KF-3)
文摘Al-doped ZnO（AZO） thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures（P_（O2））.The effect of P_（O2） on the crystal structure,preferred orientation as well as the electrical and optical properties of the films was investigated.The structure characterizations indicated that the as-grown films were single-phased with a wurtzite ZnO structure,showing a significant c-axis orientation.The films were well crystallized and exhibited better crystallinity and denser texture when deposited at higher P_（O2）.At the optimum oxygen partial pressures of 10- 15 Pa,the AZO thin films were epitaxially grown on c-sapphire substrates with the（0001） plane parallel to the substrate surface,i e,the epitaxial relationship was AZO（000 1） // A1_2O_3（000 1）.With increasing P_（O2）,the value of Hall carrier mobility was increased remarkably while that of carrier concentration was decreased slightly,which led to an enhancement in electrical conductivity of the AZO thin films.All the films were highly transparent with an optical transmittance higher than 85%.
文摘Flexible triboelectric nanogenerators (TENGs)-based pressure sensors are very essential for the wide-range applications, comprising wearable healthcare systems, intuitive human-device interfaces, electronic-skin (e-skin), and artificial intelligence. Most of conventional fabrication methods used to produce high-performance TENGs involve plasma treatment, photolithography, printing, and electro-deposition. However, these fabrication techniques are expensive, multi-step, time-consuming and not suitable for mass production, which are the main barriers for efficient and cost-effective commercialization of TENGs. Here, we established a highly reliable scheme for the fabrication of a novel eco-friendly, low cost, and TENG-based pressure sensor (TEPS) designed for usage in self-powered-human gesture detection (SP-HGD) likewise wearable healthcare applications. The sensors with microstructured electrodes performed well with high sensitivity (7.697 kPa^-1), a lower limit of detection (~ 1 Pa), faster response time (< 9.9 ms), and highly stable over > 4,000 compression-releasing cycles. The proposed method is suitable for the adaptable fabrication of TEPS at an extremely low cost with possible applications in self-powered systems, especially e-skin and healthcare applications.
文摘Interleukin 12(IL-12)and/or interleukin 18(IL-18)gene ablated mice were applied for the investigation of the tissue expression of interferon γ(IFN-γ).For IL-12^(-/-),IL-18^(-/-),IL-12^(-/-)/18^(-/-) and wt mice,reproductive performance were recorded and IFN-γ concentrations in heart,lung,liver,spleen,kidney and serum were quantified by ELISA. There were no significant differences of IFN-γ in heart,lung and kidney between 4 strains although control group was higher.It was observed that for IL-12^(-/-) mice,compared with other 3 groups,IFN-γ in liver and spleen were decreased(p<0.05)and reproductive performance appeared to be impaired.Serum IFN-γ level of IL-12^(-/-)/18^(-/-) mice was significantly higher(p<0.05).It was showed that IFN-γ productions under the normal condition were independent upon IL-12 and IL-18,its expressions in various tissues were different,and optimal IFN-γ is necessary for the normal growth and development of mammals.This study is helpful for clinical cytokines therapy.Cellular & Molecular Immunology.2005;2(1):68-72.
文摘Radiofrequency ablation(RFA),particularly endoscopic ultrasound-guided RFA(EUS-RFA),has emerged as a promising minimally invasive approach for the treatment of pancreatic cancer,especially in patients with locally advanced or unresectable disease.This review outlines recent technological developments in EUS-RFA,including innovations in energy delivery systems,probe design,and real-time thermal monitoring,which have improved the precision and safety of the procedure.Clinical studies combining EUS-RFA with chemotherapy have demonstrated encouraging outcomes,with improvements in overall survival,progression-free survival,tumor necrosis,and symptom control compared to chemotherapy alone.Additionally,RFA-induced tumor antigen release and modulation of the tumor microenvironment suggest a potential synergistic role with immunotherapy.Despite its promise,the widespread adoption of EUS-RFA is limited by a lack of large-scale randomized controlled trials and standardized treatment protocols.
文摘BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two techniques in treatment-naive HCC.AIM To compare the risk of local tumor progression(LTP)according to the technique;secondary endpoints included technique efficacy rate at one-month,overall survival and major complication rate.METHODS A bi-institutional retrospective analysis of patients undergoing treatment-naive HCC ablation by either technique was performed.Inverse probability of treatment weighting was used to compare the two groups.Mixed effects multivariate Cox regression was applied to identify risk factors for LTP.RESULTS A total of 362 patients(mean age,66.1±6.2 years,308 men)were included,of which 242(323 tumors)treated by mbp-RFA and 120(168 tumors)by MWA.After a median follow-up of 27 months,cumulative LTP was 11.4%after mbp-RFA and 25.2%after MWA.Independent risk factors for LTP at multivariate analysis were MWA(hazard ratio=2.85,P<0.001)and tumor size(hazard ratio=1.08,P<0.001).Two-year LTP-free survival was higher after mbp-RFA than MWA regardless of size(<3 cm:96%vs 87.1%,P<0.01;≥3 cm:87.5%vs 74%,P=0.04).Technique efficacy rate was higher after mbp-RFA(94.1%vs 87.5%,P=0.01).No difference was observed in major complication rate(9.5%vs 7.5%,P=0.59),nor 5-year overall survival(63.6%vs 58.3%,P=0.33).CONCLUSION Mbp-RFA leads to better local tumor control of treatment-naïve HCC than MWA regardless of tumor size and has better primary efficacy,while maintaining a comparable safety profile.
文摘Colorectal cancer(CRC)with lung oligometastases,particularly in the presence of extrapulmonary disease,poses considerable therapeutic challenges in clinical practice.We have carefully studied the multicenter study by Hu et al,which evaluated the survival outcomes of patients with metastatic CRC who received image-guided thermal ablation(IGTA).These findings provide valuable clinical evidence supporting IGTA as a feasible,minimally invasive approach and underscore the prognostic significance of metastatic distribution.However,the study by Hu et al has several limitations,including that not all pulmonary lesions were pathologically confirmed,postoperative follow-up mainly relied on dynamic contrast-enhanced computed tomography,no comparative analysis was performed with other local treatments,and the impact of other imaging features on efficacy and prognosis was not evaluated.Future studies should include complete pathological confirmation,integrate functional imaging and radiomics,and use prospective multicenter collaboration to optimize patient selection standards for IGTA treatment,strengthen its clinical evidence base,and ultimately promote individualized decision-making for patients with metastatic CRC.
文摘Over the past ten years,numerous papers have been published on the use of indocyanine green(ICG)fluorescence in liver surgery for hepatocellular carcinoma(HCC).There are many different applications.The first involves targeting superficial tumors in patients with macronodular cirrhosis and an irregular liver surface.In a minimally invasive setting,the lack of tactile feedback on the hepatic surface makes detecting subcapsular HCC with ultrasound alone challenging.ICG fusion images can mimic the tactile feedback of the hand and act as an ultrasound booster.ICG fluorescence can be used to evaluate tumor residues after minimally invasive thermal ablation.ICG fluorescence imaging can also be used to identify the grade of HCC early on and evaluate the microinvasive component.
基金supported by the National Key Basic Research Program of China (Grant No. 2014CB931704)the National Natural Science Foundation of China (Grant No. 11304315, 51401206, 11404338, 51371166, 51571186, and 11504375)the Chinese Academy of Sciences/State Administration of Foreign Experts Affairs (CAS/SAFEA) International Partnership Program for Creative Research Teams
文摘Laser ablation in liquids has emerged as a new branch of nanoscience for developing various nanomaterials with different shapes.However, how to design and control nanomaterial growth is still a challenge due to the unique chemical-physical process chain correlated with nanomaterial nucleation and growth, including plasma phase(generation and rapid quenching), gas(bubble) phase,and liquid phase. In this review, through summarizing the literature about this topic and comparing with the well-established particle growth mechanisms of the conventional wet chemistry technique, our perspective on the possible nanoparticle growth mechanisms or routes is presented, aiming at shedding light on how laser-ablated particles grow in liquids. From the microscopic viewpoint, the nanoparticle growth contains six mechanisms, including LaMer-like growth, coalescence, Ostwald ripening, particle(oriented) attachment, adsorbate-induced growth and reaction-induced growth. For each microscopic growth mechanism, the vivid growth scenes of some representative nanomaterials recorded by TEM and SEM measurements are displayed. Afterwards,the scenes from the macroscopic viewpoint for the large submicro-and micro-scale nanospheres and anisotropic nanostructures formation and evolution from one nanostructure into another one are presented. The panorama of how diverse nanomaterials grow during and after laser ablation in liquids shown in this review is intended to offer a overview for researchers to search for the possible mechanisms correlated to their synthesized nanomaterials, and more expectation is desired to better design and tailor the morphology of the nanocrystals synthesized by LAL technique.
文摘Irreversible electroporation(IRE)is a new cancer ablation technology,but methods to improve IRE-induced therapeutic immunity are only beginning to be investigated.We developed a mouse model bearing large primary(300 mm^(3))and medium distant(100 mm^(3))EG7 lymphomas engineered to express ovalbumin(OVA)as a nominal tumor antigen.We established experimental protocols including IRE alone and IRE combined with Toll-like receptor(TLR)3/9 agonists(poly I:C/CpG)(IRE+pIC/CpG),PD-1 blockade(IRE+PD-1 blockade),or both(IRE+Combo)to investigate therapeutic effects on primary and distant EG7 tumors and conversion-promoting effects on the immunotolerant tumor microenvironment(TME).We demonstrated that IRE alone simulated very weak OVA-specific CD8^(+)T cell responses and did not inhibit primary tumor growth.IRE+pIC/CpG synergistically stimulated more efficient OVA-specific CD8^(+)T cell responses and primary tumor growth inhibition than IRE+PD-1 blockade.IRE+pIC/CpG played a major role in the modulation of immune cell profiles but a minor role in the downregulation of PD-L1 expression in the TME and vice versa for IRE+PD-1 blockade.IRE+Combo cooperatively induced potent OVA-specific CD8^(+)T cell immunity and rescued exhausted intratumoral CD8^(+)T cells,leading to eradication of not only primary tumors but also untreated concomitant distant tumors and lung metastases.IRE+Combo efficiently modulated immune cell profiles,as evidenced by reductions in immunotolerant type-2(M2)macrophages,myeloid-derived suppressor-cells,plasmacytoid dendritic cells,and regulatory T cells and by increases in immunogenic M1 macrophages,CD169^(+)macrophages,type-1 conventional dendritic cells,and CD8^(+)T cells,leading to conversion of immunotolerance in not only primary TMEs but also untreated distant TMEs.IRE+Combo also showed effective therapeutic effects in two breast cancer models.Therefore,our results suggest that IRE+Combo is a promising strategy to improve IRE ablation therapy in cancer.
文摘Mass, velocity and angle distributions of the ablated species generated from 355 nm pulsed laser ablation of a LiMn2O4 target were investigated with an angle- and time-resolved mass spectrometric technique. Both neutral and ionic species of Li, O, LiO, LiO2, Mn, Li2, Li4, Li6, LiMn, MnO and MnO2 were observed at the laser fluence of 0.8 J · cm-2. The yield and variety of the ablated species increase with increasing the laser fluence. The time-of-flight spectra of ablated species can be fitted by a Maxwell-Boltzmann distribution with a center-of-mass velocity. There exist laser fluence thresholds for the ablated LiMn, Li2O and LiO2 species, and the fluence threshold of ionic species is higher than that of neutral species. The angular distributions of the ionic and neutral ablated species can be simulated by a cosηθ or a bicosine function α cosθ + (1-α) cosηθ. In addition, the ablation mechanism of LiMn2O4 by a 355 nm pulsed laser is discussed.
基金Project supported by the the National Natural-Science Foundation-of China （No.20573111） and 863 Project （No. 2005AA641020）.
文摘The gas phase reactions of metal plasma with alcohol clusters were studied by time of flight mass spectrometry （TOFMS） using laser ablation-molecular beam （LAMB） method. The significant dependence of the product cluster ions on the molecular beam conditions was observed. When the plasma acted on the low density parts of the pulsed molecular beam, the metal-alcohol complexes M^＋An （M=Cu, Al, Mg, Ni and A=C2H5OH, CH3OH） were the dominant products, and the sizes of product ion clusters were smaller. While the plasma acted on the high density part of the beam, however, the main products turned to be protonated alcohol clusters H^＋An and, as the reactions of plasma with methanol were concerned, the protonated water-methanol complexes H3O^＋（CH3OH）n with a larger size （n≤12 for ethanol and n≤24 for methanol）. Similarly, as the pressure of the carrier helium gas was varied from 1 × 10^5 to 5 × 10^5 Pa, the main products were changed from M^＋An to H^＋An and the sizes of the clusters also increased. The changes in the product clusters were attributed to the different formation mechanism of the output ions, that is, the M^＋An ions came from the reaction of metal ion with alcohol clusters, while H^＋An mainly from collisional reaction of electron with alcohol clusters.
