输尿管上段较小结石的输尿管镜治疗分析

目的以输尿管镜治疗下的输尿管上段较小结石(横径≤0.6 cm、顺径≤1.0 cm)为研究对象,分析这些结石横径、顺径、最长径与临床各事件或因素的相互关系,为输尿管上段较小结石临床合理治疗提供依据。方法搜集输尿管镜治疗的输尿管上段横径≤0.6 cm、顺径≤1.0 cm的较小结石病例共56例,分别以结石横径<0.5 cm与≥0.5 cm、横径≤0.5 cm与>0.5 cm、横径≤0.55 cm与>0.55 cm、结石顺径≤0.6 cm与>0.6 cm、顺径≤0.5 cm与>0.5 cm、结石最长径≤0.6 cm与>0.6 cm、最长径<0.6 cm与≥0.6 cm以及结石横径-顺径比值≤1与>1进行分组研究,对比每组在结石既往史、结石病程、结石移位、术前腰部酸痛症状、肾积水程度、合并输尿管狭窄、合并输尿管息肉、合并输尿管狭窄或息肉和输尿管镜治疗成功率等方面的差异,同时研究结石横径与顺径直线线性相关性。结果结石横径<0.5 cm(21例)与≥0.5 cm(35例)分组中,两者在病程、合并输尿管狭窄、合并输尿管狭窄或息肉等方面差异有统计学意义(P<0.05或P<0.01);结石横径≤0.5 cm(31例)与>0.5 cm(25例)分组中,两者仅在合并输尿管狭窄方面差异有统计学意义(P<0.05);结石顺径≤0.5 cm(24例)与>0.5 cm(32例)、最长径<0.6 cm(23例)与≥0.6 cm(33例)分组仅在病程方面差异具有统计学意义(P<0.05);而结石横径≤0.55 cm(42例)与>0.55 cm(14例)、结石顺径≤0.6 cm(37例)与>0.6 cm(19例)、结石最长径≤0.6 cm(36例)与>0.6 cm(20例)以及结石顺径-横径比值≤1(31例)与>1(25例)等分组中,各项指标差异均无统计学意义(P>0.05);结石横径<0.5 cm组病程≤10 d且无结石移位者比例明显高于结石横径≥0.5 cm组(P<0.05);并且均合并输尿管狭窄或息肉,结石横径与顺径成直线线性相关。结论结石横径,而非顺径或最长径,可作为输尿管上段较小结石简化测量指标,并在其相关治疗中具有重要临床意义。对于横径<0.5 cm的输尿管上段结石,非结石体积相关的机械梗阻因素占主导,短期内(10 d)不移位即可作为非药物治疗的干预指征,而输尿管镜治疗具有重要检查与治疗意义。

力学的基本概念(3) 没有转动的惯性离心力

论证不通过惯性系原点作惯性直线运动的质点及在角动量守恒的条件下作曲线运动的质点均有形式相同的离开原点的惯性离心力.推导在位矢方向牛顿力与惯性离心力共存时力和总加速度的一般关系式及特殊关系式.

Surgical outcome of pancreatic cancer using radical antegrade modular pancreatosplenectomy procedure

AIM:To evaluate the surgical outcomes following radical antegrade modular pancreatosplenectomy (RAMPS) for pancreatic cancer. METHODS:Twenty-four patients underwent RAMPS with curative intent between January 2005 and June 2009 at the National Cancer Center, South Korea. Clinicopathologic data, including age, sex, operative findings, pathologic results, adjuvant therapy, postop-erative clinical course and follow-up data were retro-spectively collected and analyzed for this study. RESULTS:Twenty-one patients (87.5%) underwent distal pancreatectomy and 3 patients (12.5%) underwent total pancreatectomy using RAMPS. Nine patients (37.5%) underwent combined vessel resection, including 8 superior mesenteric-portal vein resections and 1 celiac axis resection. Two patients (8.3%) underwent combined resection of other organs, including the colon, stomach or duodenum. Negative tangential margins were achieved in 22 patients (91.7%). The mean tumor diameter for all patients was 4.09 ± 2.15 cm. The 2 patients with positive margins had a mean diameter of 7.25 cm. The mean number of retrieved lymph nodes was 20.92 ± 11.24 and the node positivity rate was 70.8%. The median survival of the 24 patients was 18.23 ± 6.02 mo. Patients with negative margins had a median survival of 21.80 ± 5.30 mo and those with positive margins had a median survival of 6.47 mo (P = 0.021). Nine patients (37.5%) had postoperative complications, but there were no postoperative mortalities. Pancreatic fistula occurred in 4 patients (16.7%):2 patients had a grade A fistula and 2 had a grade B fistula. On univariate analysis, histologic grade, positive tangential margin, pancreatic fistula and adjuvant therapy were significant prognostic factors for survival. CONCLUSION:RAMPS is a feasible procedure for achieving negative tangential margins in patients with carcinoma of the body and tail of the pancreas.

Effects of residual motion compensation errors on the performance of airborne along-track interferometric SAR

Two approximations, center-beam approximation and reference digital elevation model （DEM） approximation, are used in synthetic aperture radar （SAR） motion compensation procedures. They usually introduce residual motion compensation errors for airborne single-antenna SAR imaging and SAR interferometry. In this paper, we investigate the effects of residual uncompensated motion errors, which are caused by the above two approximations, on the performance of airborne along-track interferometric SAR （ATI-SAR）. The residual uncompensated errors caused by center-beam approximation in the absence and in the presence of elevation errors are derived, respectively. Airborne simulation parameters are used to verify the correctness of the analysis and to show the impacts of residual uncompensated errors on the interferometric phase errors for ATI-SAR. It is shown that the interferometric phase errors caused by the center-beam approximation with an accurate DEM could be neglected, while the interferometric phase errors caused by the center-beam approximation with an inaccurate DEM cannot be neglected when the elevation errors exceed a threshold. This research provides theoretical bases for the error source analysis and signal processing of airborne ATI-SAR.

The internalization pathway,metabolic fate and biological effect of superparamagnetic iron oxide nanoparticles in the macrophage-like RAW264.7 cell

The potential applications of superparamagnetic iron oxide nanoparticles （SPIONs） in several nanomedical fields have attract- ed intense interest based on the cell-nano interaction. However, the mechanisms underlying cell uptake, the intracellular trail, final fate and the biological effects of SPIONs have not yet been clearly elucidated. Here, we showed that multiple endocytic pathways were involved in the internalization process of SPIONs in the RAW264.7 macrophage. The internalized SPIONs were biocompatible and used three different metabolic pathways： The SPIONs were distributed to daughter cells during mito- sis; they were degraded in the lysosome and free iron was released into the intracellular iron metabolic pool; and, the intact SPIONs were potentially exocytosed out of the cells. The internalized SPIONs did not induce cell damage hut affected iron metabolism, inducing the upregulation of ferritin light chain at both the mRNA and protein levels and ferroportin 1 at the mRNA level. These results may contribute to the development of nanobiology and to the safe use of SPIONs in medicine when administered as a contrast medium or a drug delivery tool.

Observation of the supercritical Pearl River plume front under the downwelling-favorable winds

For the Pearl River plume, the supercritical, distinct plume front appears in downwelling-favorable winds, which is easily observed due to the distinct boundary between the plume water and the ambient water. In this paper, in situ and satellite observations of a plume front are utilized to explore the Pearl River plume front properties under the downwelling-favorable winds. Field observations clearly show frontal structure, especially the two-layer structure in the plume water and the downward-motion of water in the frontal region. The Advanced Synthetic Aperture Radar(ASAR) images are also analyzed to unveil the plume front: there is a white stripe on the west side out of the river mouth under downwelling-favorable winds, which is identified as a supercritical plume front, and the width of the plume front is about 250 m. The normalized velocity gradient shows the intense velocity convergence in the front region. Also, analyses of ASAR images imply that the river discharge plays an important role in controlling the location and shape of the front.

Chronological constraints on multi-staged rapid cooling of the Tianshan Mountains inferred from apatite fission track analysis of modern river sands

The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track （AFI） chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and -3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozo- ic tectonic uplift of the mountains and regional climate change.