内镜黏膜下剥离术治疗大肠侧向发育型肿瘤的临床效果

目的探讨内镜黏膜下剥离术(ESD)治疗大肠侧向发育型肿瘤的临床效果。方法选取2015年1月~2018年5月广东省梅州市人民医院收治的90例大肠侧向发育型肿瘤患者作为研究对象,根据随机数字表法分为对照组(45例)和观察组(45例)。对照组患者采用内镜下黏膜切除术(EMR)治疗,观察组患者采用ESD治疗。随访12个月,比较两组患者的手术指标、并发症发生率及复发率。结果两组患者的术中出血量比较,差异无统计学意义(P>0.05);观察组患者的整块切除率、完整切除率均高于对照组,差异有统计学意义(P<0.05);观察组患者术后迟发性出血、肠穿孔、切口感染的发生率均低于对照组,差异有统计学意义(P<0.05);两组患者术后6个月的复发率比较,差异无统计学意义(P>0.05);观察组患者术后12个月的复发率低于对照组,差异有统计学意义(P<0.05)。结论ESD治疗大肠侧向发育型肿瘤的手术创伤较小,病灶整块切除率、完整切除率优于EMR,且复发率较低,未增加并发症发生率,值得推广应用。

腰骶椎轴向螺钉的设计及生物力学测试

背景:经骶骨前入路的经皮腰骶椎前柱内固定系统即Axia LIF先后在美国及欧洲应用于临床,取得较好的临床疗效,但是在应用过程中出现了如内固定下沉、内固定控制旋转能力较差等一系列问题。目的:根据国人腰椎侧位片及CT横断面测量的解剖数据自行设计腰骶椎轴向螺钉,制成成品后在体外生物标本上进行三维运动实验和轴向抗压缩实验,对其固定节段的稳定性及轴向抗压刚度进行生物力学评价。方法:选取新鲜成人脊柱标本(L3-S5节段)6具,按正常组、峡部裂组、普通轴向螺钉固定组、自行设计轴向螺钉固定组顺序依次进行生物力学测试,分别测试各实验组在屈伸、左侧屈、左旋转运动状态下L5/S1节段的运动范围及轴向抗压缩位移。结果与结论:(1)在三维运动实验中,峡部裂组的ROM在屈伸及左旋转方向上均显著大于正常组(P<0.05),在左侧弯方向上与正常组差异无显著性意义(P>0.05);(2)普通螺钉固定组与自制螺钉固定组的ROM在屈伸、左侧弯方向上均显著小于正常组(P<0.05),在左旋转方向上与正常组差异无显著性意义(P>0.05),普通螺钉固定组与自制螺钉固定组间比较差异无显著性意义(P>0.05);(3)在1 000 N的轴向载荷压缩实验中,4组所产生的压缩位移差异有显著性意义(P<0.05),自制螺钉固定组<普通螺钉固定组<正常组<峡部裂组;(4)根据力学公式EF=P/v L,结合压缩位移结果,计算出轴向压缩刚度值,自制螺钉固定组>普通螺钉固定组>正常组>峡部裂组;(5)提示自行设计轴向螺钉可以显著提高腰骶椎在后柱失稳情况下各个运动方向的稳定性,与普通轴向螺钉相当,但在轴向抗压刚度方面明显强于普通轴向螺钉,为在防止轴向螺钉固定脊柱节段沉降和前凸损失方面提供了一种有效的解决思路。

ERCP、MRCP、CT、B超对胆总管结石的诊断价值分析

目的探究分析在胆总管结石的诊断过程中应用ERCP、MRCP、CT、B超的价值。方法该院消化内科中心2018年1月—2019年12月期间经ERCP明确诊断胆总管结石病例中随机选取120例作为观察对象,其中97例患者接受MRCP诊断检查,105例患者接受CT诊断检查,96例患接受B超诊断检查。以ERCP诊断结果标准,统计MRCP、CT、B超诊断结果 ,分析其诊断正确率。结果接受MRCP诊断检查的97例患者中,诊断结果为胆总管结石的患者有58例,诊断正确率为59.79%;接受CT诊断检查的105例患者中,诊断结果为胆总管结石的患者有69例,诊断正确率为65.71%;接受B超诊断检查的96例患者中,诊断结果为胆总管结石的患者有37例,诊断正确率为38.54%。结论在诊断胆总管结石过程中,应用B超诊断检查具有一定的局限性,可用于筛查胆总管结石,MRCP与CT诊断检查的正确率较高,在临床工作中可灵活进行诊断检查方式的选择。

Soil animals and nitrogen mineralization under sand-fixation plantations in Zhanggutai region,China

The effects of soil animals on soil nitrogen (N) mineralization and its availability were studied by investigating soil animal groups and their amounts of macro-faunas sorted by hand, and middle and microfaunas distinguished with Tullgren and Baermann methods under three Pinus sylvestris var. mongolica Litv. plantations in Zhanggutai sandy land, China. In addition, soil N mineralization rate was also measured with PVC closed-top tube in situ incubation method. The soil animals collected during growing season belonged to 13 orders, 5 groups, 4 phyla, whose average density was 86 249.17 individuals·m^(-2). There were significant differences in soil animal species, densities, diversities and evenness among three plantations. Permanent grazing resulted in decrease of soil animal species and diversity. The average ammonification, nitrification and mineralization rates were 0.48 g·m^(-2)·a^(-1), 3.68 g·m^(-2)·a^(-1) and 4.16 g·m^(-2)·a^(-1), respectively. The ammonification rate in near-mature forest was higher than that in middle-age forests, while the order of nitrification and net mineralization rates was: middle-age forest without grazing < middle-age forest with grazing < near-mature forest with grazing (P<0.05). Soil N mineralization rate increased with soil animal amounts, but no significant relationship with diversity. The contribution of soil animals to N mineralization was different for different ecosystems due to influences of complex factors including grazing, soil characteristics, the quality and amount of litter on N mineralization.

Effect of Land Cover Change on Soil Phosphorus Fractions in Southeastern Horqin Sandy Land, Northern China

In the past 50 years, large areas of the Horqin sandy land were afforested to prevent desertification. Although the afforestation policy appears successful, many people now doubt whether it is suitable to plant trees with high density on the poor soils in semiarid regions. Little is known about the impacts of afforestation on the sandy soil properties, although the evaluation of these impacts is fundamental to judge the rationality of afforestation policy. Soil phosphorus (P) fractions, acid phosphomonoesterase activities, and other soil chemical properties were compared among five adjoining typical ecosystems on poor sandy soils in southeastern Horqin sandy land. The ecosystems studied are natural elm savanna, degraded grassland, Mongolian pine (Pinus sylvestris var. mongolica) plantation, Chinese pine (Pinus tabulaeformis) plantation, and mixed plantation of Mongolian pine and poplar (Populus simonii). The results showed that organic P dominated soil P (47%–65%) was the principal source of available P. The degradation of elm savanna to grassland significantly reduced soil pH and resulted in an overall reduction in soil fertility, although slightly increased labile inorganic P. Grassland afforestation had no significant influence on soil pH, organic carbon, and total N but significantly reduced total P. Impacts of grassland afforestation on soil P fractions depended on tree species. Natural elm savanna had higher soil P conserving ability than artificial plantations. Therefore, with the aim of developing a sustainable ecosystem, we suggested that vegetations with low nutrient demand (particularly P) and effcient nutrient cycling would be more suitable for ecosystem restoration in the semiarid region.

Soil Inorganic Nitrogen and Microbial Biomass Carbon and Nitrogen Under Pine Plantations in Zhanggutai Sandy Soil

The dynamics of soil inorganic nitrogen (NH4+ -N and NO-3 -N) and microbial biomass carbon (Cmic) and nitrogen (Nmic) under 30-year-old fenced Pinus sylvestris L. var. mongolica Litvin (SF), unfenced P. sylvestris L. var. mongolica Litvin (SUF), and unfenced Pinus densiflora Siebold et Zucc. (DUF) plantations in the Zhanggutai sandy soil of China were studied during Apr. to Oct. 2004 by the in situ closed-top core incubation method. All mentioned C and N indices in each stand type fluctuated over time. The ranges of inorganic N, Cmic, and Nmic contents in the three stand types were 0.7–2.6, 40.0–128.9, and 5.4–15.2 μg g-1, respectively. The average contents of soil NH4+ -N and Cmic under the three 30-year-old pine plantations were not different. However, soil NO3 -N and total inorganic N contents decreased in the order of SUF ≥ SF ≥ DUF, the Nmic content was in the order of SF = SUF > DUF, and the Cmic:Nmic ratio was in the order of SUF = DUF > SF. Seasonal variations were observed in soil inorganic N, microbial biomass, and plant growth. These seasonal variations had certain correlations with microbe and plant N use in the soil, and their competition for NH+4 -N was mostly regulated by soil N availability. The influence of tree species on inorganic N and Nmic were mainly because of differences in litter quality. Lack of grazing decreased the Cmic:Nmic ratio owing to decreased carbon output and increased the ability of soil to supply N. The soil N supply under the P. sylvestris var. mongolica plantation was lower than under the P. densiflora plantation.

Small-Scale Spatial Variability of Soil Nutrients and Vegetation Properties in Semi-Arid Northern China

A field experiment was conducted at Kezuohouqi County, Inner Mongolia Autonomous Region of China, which was located on the southeastern edge of the Horqin Sandy Land, to study the spatial variability of soil nutrients for a smallscale, nutrient-poor, sandy site in a semi-arid region of northern China; to investigate whether or not there were 'islands of fertility' at the experimental site; and to determine the key nutrient elements that sustained ecosystem stability. Results obtained from geostatistical analysis indicated that the spatial distribution pattern of soil total nitrogen (STN) was far different from those of soil organic matter (SOM), total phosphorus (STP), and total potassium (STK). Compared to SOM, STP, and STK, STN had a lower structural heterogeneity ratio and a longer range, while other elements were all similar. In addition, STN had an isotropic spatial structure, whereas the others had an anisotropic spatial structure. The spatial structure patterns of herbage species, cover,and height also differed, indicating that spatial variability was subjected to different ecological factors. Differences in the spatial variability patterns among soil nutrients and vegetation properties showed that soil nutrients for a small-scale were not the primary limiting factors that influenced herbage spatial distribution patterns. Incorporating spatial distribution patterns of tree species, namely, Pinus sylvestris var. mongolica Litv. and shrub Lespedeza bicolor Turcz. in a research plot and using fractal dimension,SOM, STP, and STK were shown to contribute to the 'islands of fertility' phenomenon, however STN was not, possibly meaning that nitrogen was a key limiting element. Therefore, during restoration of similar ecosystems more attention should be given to soil nitrogen.

煤矸石酸浸液亚铁氰化钾深度脱铁实验研究

以煤矸石酸浸液经初步脱铁反应后的溶液为研究对象,通过对其组分含量的分析,结果表明:100g煤矸石经初步脱铁后,酸浸液中Al2O3,Fe2O3质量分别为32.50,0.21g,其中铁质量没有达到制备无铁级硫酸铝的要求。因此,本研究取初步脱铁反应后的溶液500mL,通过添加除铁剂亚铁氰化钾进行深度脱铁,系统研究了反应温度、反应时间和亚铁氰化钾加量对脱铁的影响,以溶液中Fe2O3的最终质量为指标来考察各因素对除铁效果的影响,确定最优的工艺条件。研究结果表明:反应温度为20℃,反应时间为0.5h,亚铁氰化钾加量为1.79g时,除铁率达到97.46%,此时溶液的铁质量是达到制备无铁级硫酸铝的要求,研究成果具有较好的应用前景。

Phosphorus fractions and phosphomonoesterase activities in sandy soils under a temperate savanna and a neighboring Mongolian pine plantation

To assess the effects of savanna afforestation on soil phosphorus （P） transformations in eastern Horqin Sandy Land, China, P fractions and phosphomonoesterase activities were examined in two soil horizons （0-5 cm and 5-20 cm） under a savanna and an adjacent 30-year-old Mongolian pine （Pinus sylvestris L. vat. mongolica Litv.） plantation on a P-deficient semi arid sandy soil. The results showed that all soil P fractions and phosphomonoestcrase activities decreased with soil depth at both sites except that labile organic P under the plantation was constant with soil depth, In contrast to savanna, soils trader Mongolian pine plantation had lower phosphomonoesterase activities and concentrations of all P fractions （with an exception of Al-P）, lower proportions of organic P and Ca-P in total P, and higher proportions of labile P, Al-P and Fe-P in total P. These results suggested that P transformations mainly occurred in surface soils, and P recycled through litterfall was the most important source of plant available P. Mongolian pine afforestation enhanced the bioavailability of both organic P and Ca-P. simultaneously reduced soil P pools. indicating that protection of forest floor and P fertilization are necessary to maintain the sustainable functioning of Mongolian pine plantations.

基于NX的旋耕刀三维建模及结构优化

为了提高旋耕机的切削效率和使用性能,以R245弯形旋耕刀为主要研究对象,介绍了旋耕刀的结构和工作原理,阐述了建模、有限元分析及优化的方法步骤。首先运用NX软件基于表达式对刀片进行三维建模,然后通过NX NASTRAN模块建立有限元模型并求解,最后进行了应力仿真和尺寸优化。结果表明:最大应力和变形位于旋耕刀与刀锟连接孔附近处;相同载荷作用下,优化旋耕刀主要参数尺寸,能够有效地减轻质量及降低应力和变形大小,为旋耕刀设计提供了有效的参考。