Liver malignancy,including primary liver cancer and metastatic liver cancer has become one of the most common causes of cancer-related death worldwide due to the high malignant degree and limited systematic treatment ...Liver malignancy,including primary liver cancer and metastatic liver cancer has become one of the most common causes of cancer-related death worldwide due to the high malignant degree and limited systematic treatment strategy.Radioembolization with yttrium-90(^(90)Y)-loaded microspheres is a relatively novel technology that has made significant progress in the local treatment of liver malignancy.The different steps in the extensive work-up of radioembolization for patients with an indication for treatment with^(90)Y microspheres,from patient selection to follow up,both technically and clinically,are discussed in this paper.It describes the application and development of^(90)Y microspheres in the treatment of liver cancer.展开更多
AIM: To assess the technical safety and efficacy of transcatheter arterial chemoembolization (TACE) combined with immediate radiofrequency ablation (RFA) for large hepatocellular carcinomas (HCC) (maximum diameter ≥ ...AIM: To assess the technical safety and efficacy of transcatheter arterial chemoembolization (TACE) combined with immediate radiofrequency ablation (RFA) for large hepatocellular carcinomas (HCC) (maximum diameter ≥ 5 cm). METHODS: Individual lesions in 18 patients with HCCs (mean maximum diameter: 7.5 cm; range: 5.1-15.5 cm) were treated by TACE combined with percutaneous RFA between January 2010 and June 2012. All of the patients had previously undergone one to four cycles of TACE treatment. Regular imaging and laboratory tests were performed to evaluate the rate of technical success, technique-related complications, local-regional tumor responses, recurrence-free survival time and survival rate after treatment.RESULTS: Technical success was achieved for all 18 visible HCCs. Complete response (CR) was observed in 17 cases, and partial response was observed in 1 case 1 mo after intervention. The CR rate was 94.4%. Local tumors were mainly characterized by coagulative necrosis. During follow-up (2-29 mo), the mean recurrencefree survival time was 16.8 ± 4.0 mo in 17 cases of CR. The estimated overall survival rate at 6, 12, and 18 mo was 100%. No major complications were observed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the blood of 17 patients transiently increased on the third day after treatment (ALT 200.4 ± 63.4 U/L vs 24.7 ± 9.3 U/L, P < 0.05; AST 228.1 ± 25.4 U/L vs 32.7 ± 6.8 U/L, P < 0.05). Severe pain occurred in three patients, which was controlled with morphine and fentanyl. CONCLUSION: TACE combined with immediate RFA is a safe and effective treatment for large solitary HCCs. Severe pain is a major side effect, but can be controlled by morphine.展开更多
We present a case with hepatic myelopathy(HM) due to a surgical splenorenal shunt that was successfully treated by endovascular interventional techniques.A 39-year-old man presented with progressive spastic paraparesi...We present a case with hepatic myelopathy(HM) due to a surgical splenorenal shunt that was successfully treated by endovascular interventional techniques.A 39-year-old man presented with progressive spastic paraparesis of his lower limbs 14 mo after a splenorenal shunt.A portal venogram identified a widened patent splenorenal shunt.We used an occlusion balloon catheter initially to occlude the shunt.Further monitoring of the patient revealed a decrease in his serum ammonia level and an improvement in leg strength.We then used an Amplatzer vascular plug(AVP) to enable closure of the shunt.During the follow up period of 7 mo,the patient experienced significant clinical improvement and normalization of blood ammonia,without any complications.Occlusion of a surgically created splenorenal shunt with AVP represents an alternative therapy to surgery or coil embolization that can help to relieve shunt-induced HM symptoms.展开更多
BACKGROUND Gastric cancer is the second most common malignant tumor in China,ranking third among all malignant tumor mortality rates.Hyperthermic intraperitoneal chemotherapy(HIPEC)has been shown to increase significa...BACKGROUND Gastric cancer is the second most common malignant tumor in China,ranking third among all malignant tumor mortality rates.Hyperthermic intraperitoneal chemotherapy(HIPEC)has been shown to increase significantly the effectiveness of intraperitoneal chemotherapeutic drugs,prolong the action time of these drugs on intraperitoneal tumor cells,and enhance their diffusion in tumor tissues.HIPEC may be one of the best choices for the eradication of residual cancer cells in the abdominal cavity.AIM The aim of this study was to study the role of preventive HIPEC after radical gastrectomy.METHODS A prospective analysis was performed with patients with c T4 N0-3 M0 gastric cancer to compare the effects of postoperative prophylactic HIPEC plus intravenous chemotherapy with those of routine adjuvant chemotherapy.Patients’medical records were analyzed,and differences in the peritoneal recurrence rate,diseasefree survival time,and total survival time between groups were examined.RESULTS The first site of tumor recurrence was the peritoneum in 11 cases in the conventional adjuvant chemotherapy group and in 2 cases in the HIPEC group(P=0.020).The 1-year and 3-year disease-free survival rates were 91.9%and 60.4%,respectively,in the conventional adjuvant chemotherapy group and 92.1%and 63.0%,respectively,in the HIPEC group.The 1-year and 3-year overall survival rates were 95.2%and 66.3%,respectively,in the conventional adjuvant chemotherapy group and 96.1%and 68.6%,respectively,in the HIPEC group.No significant difference in postoperative or chemotherapy complications was observed between groups.CONCLUSION In patients with c T4 N0-3 M0 gastric cancer,prophylactic HIPEC after radical tumor surgery is beneficial to reduce peritoneal tumor recurrence and prolong survival.展开更多
BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potent...BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potential to distinguish between normal liver tissue and HCC tissue; however, there are few reports on it.We conduct this observational study to explore the feasibility of THz imaging for the diagnosis of HCC.AIM To evaluate the feasibility of THz for discriminating between HCC and normal liver tissues using fresh tissue specimens obtained from HCC patients who had undergone surgery.METHODS Normal liver tissue and HCC tissue were cryosectioned into 50 μm-thick slicesand placed on cover glass. Two adjacent tissue sections were separated subjected to histopathological examination by hematoxylin and eosin staining or THz transmission examination, and THz images were compared with pathologically mapped images. We determined the typical tumor and normal liver tissue regions by pathological examination; the corresponding areas of adjacent sections were examined by THz transmission.RESULTS The transmission rate of HCC tissue was 0.15-0.25, and the transmission rate of typical HCC tissue was about 0.2. THz transmittance in normal liver tissue is slightly higher than 0.4, but there were many influencing factors, including the degree of liver cirrhosis, fat components, ice crystals in frozen sections, and apoptosis.CONCLUSION In conclusion, this study shows that THz imaging can detect HCC tissue. Further research will yield more detailed data of the THz transmission rates of HCC tissue with different degrees of differentiation.展开更多
The mechanism of self-propagating high-temperature synthesis (SHS) of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scanning ...The mechanism of self-propagating high-temperature synthesis (SHS) of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectrometry, and the combustion temperature was measured. The results showed that the com- bustion reaction started with local formation of Ti-Cu melt and could be described with the dissolution-precipitation mechanism, namely, Ti, Cu, and C particles dissolved into the Ti-Cu solution and TiC particles precipitated in the saturated Ti-Cu-C liquid solu- tion. The local formation of Ti-Cu melt resulted from the solid diffusion between Ti and Cu particles.展开更多
Prostate artery embolization is a well-known and promising treatment for benign prostatic hyperplasia, with the quantum leaps of research in medicine. We aim to provide an up-to-date review of the novel technique, inc...Prostate artery embolization is a well-known and promising treatment for benign prostatic hyperplasia, with the quantum leaps of research in medicine. We aim to provide an up-to-date review of the novel technique, including large retrospective studies and randomized control trials, ends with discussions of advantages and disadvantages of this minimally invasive technique.展开更多
An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However,most of the existing evaluation methods in basic research and clinical practice...An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However,most of the existing evaluation methods in basic research and clinical practice are not objective or intuitive for assessing the neurological function of big animals, and are also difficult to use to qualify the extent of damage and recovery. In the present study, we established a big animal model of traumatic brain injury by impacting the cortical motor region of beagles. At 2 weeks after successful modeling, we detected neurological deficiencies in the animal model using a series of techniques, including three-dimensional motion capture, electromyogram and ground reaction force. These novel technologies may play an increasingly important role in the field of traumatic brain injury diagnosis and rehabilitation in the future. The experimental protocol was approved by the Animal Care and Use Committee of Logistics University of People's Armed Police Force(approval No. 2017-0006.2).展开更多
BACKGROUND Hepatocellular carcinoma is one of the most common malignant tumors worldwide. Currently, the most accurate diagnosis imaging modality for hepatocellular carcinoma is enhanced magnetic resonance imaging. Ho...BACKGROUND Hepatocellular carcinoma is one of the most common malignant tumors worldwide. Currently, the most accurate diagnosis imaging modality for hepatocellular carcinoma is enhanced magnetic resonance imaging. However, it is still difficult to distinguish cirrhosis lesions, and novel diagnosis modalities are still needed.AIM To investigate the feasibility of hyperspectral analysis for discrimination of rabbit liver VX2 tumor.METHODS In this study, a rabbit liver VX2 tumor model was established. After laparotomy,under direct view, VX2 tumor tissue and normal liver tissue were subjected to hyperspectral analysis.RESULTS The spectral signature of the liver tumor was clearly distinguishable from that of the normal tissue, simply from the original spectral curves. Specifically, two absorption peaks at 600-900 nm wavelength in normal tissue disappeared but a new reflection peak appeared in the tumor. The average optical reflection at the whole waveband of 400-1800 nm in liver tumor was higher than that of the normal tissue.CONCLUSION Hyperspectral analysis can differentiate rabbit VX2 tumors. Further research will continue to perform hyperspectral imaging to obtain more information for differentiation of liver cancer from normal tissue.展开更多
Microstructures of GaN buffer layers grown on Si(111)substrates using rapid thermal process low-pressure metalorganic chemical vapor deposition are investigated by an atomic force microscope(AFM)and a high-resolution ...Microstructures of GaN buffer layers grown on Si(111)substrates using rapid thermal process low-pressure metalorganic chemical vapor deposition are investigated by an atomic force microscope(AFM)and a high-resolution transmission electron microscope(HBTEM).AFM images show that the islands appear in the GaN buffer layer after annealing at high temperature.Cross-sectional HBTEM micrographs of the buffer region of these samples indicate that there are bunched steps on the surface of the Si substrate and a lot of domains in GaN misorienting each other with small angles.The boundaries of those domains locate near the bunched steps,and the regions of the Him on a terrace between steps have the same crystal orientation.An amorphous-like layer,about 3nm thick,can also be observed between the GaN buffer layer and the Si substrate.展开更多
Purpose: To evaluate the early-and intermediate-term outcome in patients with symptomatic hepatic focal nodular hyperplasia(FNH) treated with transarterial embolization using bleomycin-iodinated oil and polyvinyl alco...Purpose: To evaluate the early-and intermediate-term outcome in patients with symptomatic hepatic focal nodular hyperplasia(FNH) treated with transarterial embolization using bleomycin-iodinated oil and polyvinyl alcohol(PVA) particles. Materials and methods: In this two-center retrospective study between January 2005 and December 2013, 27 consecutive patients with symptomatic hepatic FNH underwent superselective catheterization by microcatheter techniques and embolization using bleomycin-iodinated oil combined with PVA. Early-term(3–41 months) follow-up of TAE was performed in terms of symptom control, changes in lesion size, and complications. Intermediate-term(45–112 months) follow-up was carried out to assess symptom control and reinterventions for recurrence. Results: Embolization was performed in 27 patients with 31 lesions. Technical success was achieved in all cases. The follow-up period ranged from three to 112 months. At early-term follow-up, mean lesion diameters were decreased significantly from 6.4±2.7 cm pre-intervention to 3.6±1.8 cm at 3-9 months after embolization(P<0.001). A total of 7 lesions had complete resolution during the whole follow-up period. At intermediate-term follow-up, local recurrence was found in 1 treated lesion at 54-months. Contrast-enhanced scans showed complete lack of residual arterial blood supply in the majority of lesions during the follow-up period. There was no major complication associated with the procedure. Conclusion: Transarterial embolization using bleomycin-iodinated oil and PVA is a feasible, safe and effective alternative in both early-and intermediate-terms for the treatment of symptomatic hepatic FNH.展开更多
Photoreflectance was used to study the optical properties of single crystal hexagonal GaN finis on(0001)sapphire substrate grown by metalorganic chemical vapor deposition.The energy gap of GaN was determined as 3.400 ...Photoreflectance was used to study the optical properties of single crystal hexagonal GaN finis on(0001)sapphire substrate grown by metalorganic chemical vapor deposition.The energy gap of GaN was determined as 3.400 eV and the possible origin of the signal was discussed.Optical absorption and reflection were measured.The optical absorption edge of 3.38 eV,and the reilectivity peak at 3.3 eV, confirmed the results of photoreiiectance.展开更多
Raman spectra of LiNbO_(3) crystals with different hydrogen-ion-exchanged time were examined.E(TO)and A1(TO)modes appear gradually in the transverse A1-and E-symmetry spectra respectively with increasing the exchange ...Raman spectra of LiNbO_(3) crystals with different hydrogen-ion-exchanged time were examined.E(TO)and A1(TO)modes appear gradually in the transverse A1-and E-symmetry spectra respectively with increasing the exchange time and the dependence of their intensities on the exchange time is also observed.We attribute these results to both the internal strains resulting from the ordering-disordering distribution of H ions in the sample and the enhanced photorefractive effect.展开更多
We report the successful synthesis of Ge clusters embedded in a-SiNy:H matrix prepared by the plasma enhanced chemical vapor deposition(PECVD)method.Chemical and microstructural characteristics of this granular thin f...We report the successful synthesis of Ge clusters embedded in a-SiNy:H matrix prepared by the plasma enhanced chemical vapor deposition(PECVD)method.Chemical and microstructural characteristics of this granular thin film were analyzed using the infrared absorption,x-ray diffraction,Raman scattering,and transmission electron microscopy.Finally we discuss briefly the synthesis mechanism of this new material.展开更多
By flux method,potassium tantalate niobate crystals with 46%Nb contents were prepared.In this material 90°a-type domains with(011)and(01ī)walls were observed by a transmission electron microscope,and the nature ...By flux method,potassium tantalate niobate crystals with 46%Nb contents were prepared.In this material 90°a-type domains with(011)and(01ī)walls were observed by a transmission electron microscope,and the nature of fringe patterns associated with these domain walls was analysed.According to the extinction rules for the domain walls,the displacement vector R along<01ī>direction can be determined.Finally,using a selected area electron diffraction method,we examined the crystallographic character of these 90°domains and defined the ratio of lattice parameters c to a.展开更多
文摘Liver malignancy,including primary liver cancer and metastatic liver cancer has become one of the most common causes of cancer-related death worldwide due to the high malignant degree and limited systematic treatment strategy.Radioembolization with yttrium-90(^(90)Y)-loaded microspheres is a relatively novel technology that has made significant progress in the local treatment of liver malignancy.The different steps in the extensive work-up of radioembolization for patients with an indication for treatment with^(90)Y microspheres,from patient selection to follow up,both technically and clinically,are discussed in this paper.It describes the application and development of^(90)Y microspheres in the treatment of liver cancer.
文摘AIM: To assess the technical safety and efficacy of transcatheter arterial chemoembolization (TACE) combined with immediate radiofrequency ablation (RFA) for large hepatocellular carcinomas (HCC) (maximum diameter ≥ 5 cm). METHODS: Individual lesions in 18 patients with HCCs (mean maximum diameter: 7.5 cm; range: 5.1-15.5 cm) were treated by TACE combined with percutaneous RFA between January 2010 and June 2012. All of the patients had previously undergone one to four cycles of TACE treatment. Regular imaging and laboratory tests were performed to evaluate the rate of technical success, technique-related complications, local-regional tumor responses, recurrence-free survival time and survival rate after treatment.RESULTS: Technical success was achieved for all 18 visible HCCs. Complete response (CR) was observed in 17 cases, and partial response was observed in 1 case 1 mo after intervention. The CR rate was 94.4%. Local tumors were mainly characterized by coagulative necrosis. During follow-up (2-29 mo), the mean recurrencefree survival time was 16.8 ± 4.0 mo in 17 cases of CR. The estimated overall survival rate at 6, 12, and 18 mo was 100%. No major complications were observed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the blood of 17 patients transiently increased on the third day after treatment (ALT 200.4 ± 63.4 U/L vs 24.7 ± 9.3 U/L, P < 0.05; AST 228.1 ± 25.4 U/L vs 32.7 ± 6.8 U/L, P < 0.05). Severe pain occurred in three patients, which was controlled with morphine and fentanyl. CONCLUSION: TACE combined with immediate RFA is a safe and effective treatment for large solitary HCCs. Severe pain is a major side effect, but can be controlled by morphine.
文摘We present a case with hepatic myelopathy(HM) due to a surgical splenorenal shunt that was successfully treated by endovascular interventional techniques.A 39-year-old man presented with progressive spastic paraparesis of his lower limbs 14 mo after a splenorenal shunt.A portal venogram identified a widened patent splenorenal shunt.We used an occlusion balloon catheter initially to occlude the shunt.Further monitoring of the patient revealed a decrease in his serum ammonia level and an improvement in leg strength.We then used an Amplatzer vascular plug(AVP) to enable closure of the shunt.During the follow up period of 7 mo,the patient experienced significant clinical improvement and normalization of blood ammonia,without any complications.Occlusion of a surgically created splenorenal shunt with AVP represents an alternative therapy to surgery or coil embolization that can help to relieve shunt-induced HM symptoms.
文摘BACKGROUND Gastric cancer is the second most common malignant tumor in China,ranking third among all malignant tumor mortality rates.Hyperthermic intraperitoneal chemotherapy(HIPEC)has been shown to increase significantly the effectiveness of intraperitoneal chemotherapeutic drugs,prolong the action time of these drugs on intraperitoneal tumor cells,and enhance their diffusion in tumor tissues.HIPEC may be one of the best choices for the eradication of residual cancer cells in the abdominal cavity.AIM The aim of this study was to study the role of preventive HIPEC after radical gastrectomy.METHODS A prospective analysis was performed with patients with c T4 N0-3 M0 gastric cancer to compare the effects of postoperative prophylactic HIPEC plus intravenous chemotherapy with those of routine adjuvant chemotherapy.Patients’medical records were analyzed,and differences in the peritoneal recurrence rate,diseasefree survival time,and total survival time between groups were examined.RESULTS The first site of tumor recurrence was the peritoneum in 11 cases in the conventional adjuvant chemotherapy group and in 2 cases in the HIPEC group(P=0.020).The 1-year and 3-year disease-free survival rates were 91.9%and 60.4%,respectively,in the conventional adjuvant chemotherapy group and 92.1%and 63.0%,respectively,in the HIPEC group.The 1-year and 3-year overall survival rates were 95.2%and 66.3%,respectively,in the conventional adjuvant chemotherapy group and 96.1%and 68.6%,respectively,in the HIPEC group.No significant difference in postoperative or chemotherapy complications was observed between groups.CONCLUSION In patients with c T4 N0-3 M0 gastric cancer,prophylactic HIPEC after radical tumor surgery is beneficial to reduce peritoneal tumor recurrence and prolong survival.
基金Supported by the National Natural Science Foundation of China,No.11622542 and No.51677145
文摘BACKGROUND Hepatocellular carcinoma(HCC) is one of the most common malignant tumors worldwide, and novel methods for early/rapid diagnosis of HCC are needed.Terahertz(THz) spectroscopy is considered to have the potential to distinguish between normal liver tissue and HCC tissue; however, there are few reports on it.We conduct this observational study to explore the feasibility of THz imaging for the diagnosis of HCC.AIM To evaluate the feasibility of THz for discriminating between HCC and normal liver tissues using fresh tissue specimens obtained from HCC patients who had undergone surgery.METHODS Normal liver tissue and HCC tissue were cryosectioned into 50 μm-thick slicesand placed on cover glass. Two adjacent tissue sections were separated subjected to histopathological examination by hematoxylin and eosin staining or THz transmission examination, and THz images were compared with pathologically mapped images. We determined the typical tumor and normal liver tissue regions by pathological examination; the corresponding areas of adjacent sections were examined by THz transmission.RESULTS The transmission rate of HCC tissue was 0.15-0.25, and the transmission rate of typical HCC tissue was about 0.2. THz transmittance in normal liver tissue is slightly higher than 0.4, but there were many influencing factors, including the degree of liver cirrhosis, fat components, ice crystals in frozen sections, and apoptosis.CONCLUSION In conclusion, this study shows that THz imaging can detect HCC tissue. Further research will yield more detailed data of the THz transmission rates of HCC tissue with different degrees of differentiation.
基金This work was financially supported by the Natural Science Foundation of Shaanxi Province, China (No.2004E107)
文摘The mechanism of self-propagating high-temperature synthesis (SHS) of TiC-Cu cermets was studied using a combustion front quenching method. Microstructural evolution in the quenched sample was observed using scanning electron microscope (SEM) with energy dispersive X-ray (EDX) spectrometry, and the combustion temperature was measured. The results showed that the com- bustion reaction started with local formation of Ti-Cu melt and could be described with the dissolution-precipitation mechanism, namely, Ti, Cu, and C particles dissolved into the Ti-Cu solution and TiC particles precipitated in the saturated Ti-Cu-C liquid solu- tion. The local formation of Ti-Cu melt resulted from the solid diffusion between Ti and Cu particles.
文摘Prostate artery embolization is a well-known and promising treatment for benign prostatic hyperplasia, with the quantum leaps of research in medicine. We aim to provide an up-to-date review of the novel technique, including large retrospective studies and randomized control trials, ends with discussions of advantages and disadvantages of this minimally invasive technique.
基金supported by the National Natural Science Foundation of China,No.11672332,11102235 and 31200809(all to XYC)the National Key Research and Development Plan of China,No.2016YFC1101500(to SZ)the Science and Technology Program of Tianjin,China,No.17YFZCSY00620 and 16ZXHLSY00120(both to XYC)
文摘An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However,most of the existing evaluation methods in basic research and clinical practice are not objective or intuitive for assessing the neurological function of big animals, and are also difficult to use to qualify the extent of damage and recovery. In the present study, we established a big animal model of traumatic brain injury by impacting the cortical motor region of beagles. At 2 weeks after successful modeling, we detected neurological deficiencies in the animal model using a series of techniques, including three-dimensional motion capture, electromyogram and ground reaction force. These novel technologies may play an increasingly important role in the field of traumatic brain injury diagnosis and rehabilitation in the future. The experimental protocol was approved by the Animal Care and Use Committee of Logistics University of People's Armed Police Force(approval No. 2017-0006.2).
文摘BACKGROUND Hepatocellular carcinoma is one of the most common malignant tumors worldwide. Currently, the most accurate diagnosis imaging modality for hepatocellular carcinoma is enhanced magnetic resonance imaging. However, it is still difficult to distinguish cirrhosis lesions, and novel diagnosis modalities are still needed.AIM To investigate the feasibility of hyperspectral analysis for discrimination of rabbit liver VX2 tumor.METHODS In this study, a rabbit liver VX2 tumor model was established. After laparotomy,under direct view, VX2 tumor tissue and normal liver tissue were subjected to hyperspectral analysis.RESULTS The spectral signature of the liver tumor was clearly distinguishable from that of the normal tissue, simply from the original spectral curves. Specifically, two absorption peaks at 600-900 nm wavelength in normal tissue disappeared but a new reflection peak appeared in the tumor. The average optical reflection at the whole waveband of 400-1800 nm in liver tumor was higher than that of the normal tissue.CONCLUSION Hyperspectral analysis can differentiate rabbit VX2 tumors. Further research will continue to perform hyperspectral imaging to obtain more information for differentiation of liver cancer from normal tissue.
基金Supported by Project of High Technology Research&Development of China(863-715-011-0030),Project of Fundamental Research of China,the National Natural Science Foundation of China under Grant Nos.69636010 and 69636040,and MOTOROLA(China Inc.)Semiconductor Scholarship.
文摘Microstructures of GaN buffer layers grown on Si(111)substrates using rapid thermal process low-pressure metalorganic chemical vapor deposition are investigated by an atomic force microscope(AFM)and a high-resolution transmission electron microscope(HBTEM).AFM images show that the islands appear in the GaN buffer layer after annealing at high temperature.Cross-sectional HBTEM micrographs of the buffer region of these samples indicate that there are bunched steps on the surface of the Si substrate and a lot of domains in GaN misorienting each other with small angles.The boundaries of those domains locate near the bunched steps,and the regions of the Him on a terrace between steps have the same crystal orientation.An amorphous-like layer,about 3nm thick,can also be observed between the GaN buffer layer and the Si substrate.
文摘Purpose: To evaluate the early-and intermediate-term outcome in patients with symptomatic hepatic focal nodular hyperplasia(FNH) treated with transarterial embolization using bleomycin-iodinated oil and polyvinyl alcohol(PVA) particles. Materials and methods: In this two-center retrospective study between January 2005 and December 2013, 27 consecutive patients with symptomatic hepatic FNH underwent superselective catheterization by microcatheter techniques and embolization using bleomycin-iodinated oil combined with PVA. Early-term(3–41 months) follow-up of TAE was performed in terms of symptom control, changes in lesion size, and complications. Intermediate-term(45–112 months) follow-up was carried out to assess symptom control and reinterventions for recurrence. Results: Embolization was performed in 27 patients with 31 lesions. Technical success was achieved in all cases. The follow-up period ranged from three to 112 months. At early-term follow-up, mean lesion diameters were decreased significantly from 6.4±2.7 cm pre-intervention to 3.6±1.8 cm at 3-9 months after embolization(P<0.001). A total of 7 lesions had complete resolution during the whole follow-up period. At intermediate-term follow-up, local recurrence was found in 1 treated lesion at 54-months. Contrast-enhanced scans showed complete lack of residual arterial blood supply in the majority of lesions during the follow-up period. There was no major complication associated with the procedure. Conclusion: Transarterial embolization using bleomycin-iodinated oil and PVA is a feasible, safe and effective alternative in both early-and intermediate-terms for the treatment of symptomatic hepatic FNH.
文摘Photoreflectance was used to study the optical properties of single crystal hexagonal GaN finis on(0001)sapphire substrate grown by metalorganic chemical vapor deposition.The energy gap of GaN was determined as 3.400 eV and the possible origin of the signal was discussed.Optical absorption and reflection were measured.The optical absorption edge of 3.38 eV,and the reilectivity peak at 3.3 eV, confirmed the results of photoreiiectance.
文摘Raman spectra of LiNbO_(3) crystals with different hydrogen-ion-exchanged time were examined.E(TO)and A1(TO)modes appear gradually in the transverse A1-and E-symmetry spectra respectively with increasing the exchange time and the dependence of their intensities on the exchange time is also observed.We attribute these results to both the internal strains resulting from the ordering-disordering distribution of H ions in the sample and the enhanced photorefractive effect.
基金the National Natural Science Foundation of China.
文摘We report the successful synthesis of Ge clusters embedded in a-SiNy:H matrix prepared by the plasma enhanced chemical vapor deposition(PECVD)method.Chemical and microstructural characteristics of this granular thin film were analyzed using the infrared absorption,x-ray diffraction,Raman scattering,and transmission electron microscopy.Finally we discuss briefly the synthesis mechanism of this new material.
基金Supported by the National Natural Science Foundation of China。
文摘By flux method,potassium tantalate niobate crystals with 46%Nb contents were prepared.In this material 90°a-type domains with(011)and(01ī)walls were observed by a transmission electron microscope,and the nature of fringe patterns associated with these domain walls was analysed.According to the extinction rules for the domain walls,the displacement vector R along<01ī>direction can be determined.Finally,using a selected area electron diffraction method,we examined the crystallographic character of these 90°domains and defined the ratio of lattice parameters c to a.
