大鼠食管支架置入术后再狭窄模型构建及观察

【摘要】 目的 探讨大鼠食管支架置入及术后食管良性增生性狭窄模型构建的可行性和安全性。 方法 实验使用定制的自膨式金属直筒支架（直径5 mm，长15 mm），其中部两侧各有一外突倒刺用作固定，防止滑脱移位。12只健康Sprague-Dawley大鼠随机分成A组（空白对照组）和B组（支架置入组），每组6只；B组大鼠食管内置入支架，分别于置入即刻、1周、4周作食管造影。4周后处死所有大鼠，取A组正常食管组织及B组支架部位食管组织作大体形态、光镜等病理学分析。结果 B组食管内支架置入均获成功，术后即刻、1周、4周复查造影均未发现食管内支架移位，手术及随访期间无严重并发症发生。与A组相比，4周后B组复查造影显示支架段食管增生导致食管狭窄，取出支架部位食管段肉眼见管腔明显狭窄，光镜下呈典型良性增生样表现。结论 采用大鼠构建食管支架置入后再狭窄模型安全、可行，带倒刺食管支架能够明显降低支架置入后移位发生率。

     

硅膜-镁合金可降解支架置入兔食管可行性及组织反应——体外和体内初步研究

【摘要】 目的 体外研究硅膜-镁合金可降解支架的机械特性和降解行为，体内研究其置入兔食管的可行性及组织反应。方法 体外测试硅膜-镁合金可降解支架的机械压缩恢复性能和降解行为。30只健康荷兰兔随机分为硅膜-镁合金支架组（n=15，透视导引下将支架置入兔食管下1/3段）和对照组（n=15，未作任何干预），支架置入后1、2、4周两组兔分别接受食管造影，同时于各时间点分别处死5只兔，取材作组织学检查。结果 体外测试显示硅膜-镁合金可降解支架表现出良好的柔韧性和弹性，在pH4.0、pH7.4磷酸缓冲液中降解均慢于镁合金裸支架；体内测试显示支架置入后所有实验兔耐受性良好，食管直径在置入前为（9.2±0.8） mm，置入后1、2、4周分别为（9.7±0.7） mm、（9.6±0.8） mm、（9.6±0.5） mm（P＞0.05）。支架组6只兔发生支架移位（1周时1只，2周时1只，4周时4只）。支架组食管上皮、平滑肌层变薄等食管壁重建与对照组比较，差异有统计学意义（P＜0.05）；支架置入后食管壁损伤及胶原沉积等组织反应与对照组比较，差异无统计学意义（P＞0.05）。结论 硅膜-镁合金可降解支架置入兔食管技术上可行，可提供至少2周支撑力，支架移位率可接受，未发生严重食管壁损伤及胶原沉积。

     

布加综合征下腔静脉阻塞直径３０mm大球囊扩张的可行性研究

目的探讨直径３０mm大球囊导管扩张治疗下腔静脉（IVC）阻塞型布加综合征（BCS）的可行性与安全性。方法经彩色多普勒超声（彩超）和IVC造影证实IVC阻塞的连续１４６例BCS,其中多层螺旋CT平扫及三期增强扫描４７例,经皮经腔血管成形术（PTA）治疗除１例体形矮小使用直径２５mm的球囊导管外,余１４５例均使用直径３０mm大球囊导管,PTA后IVC造影观察管腔通畅情况及管壁完整性。术后１周彩超探查胸腹部、心脏和IVC。结果术前多层螺旋CT检查除１例因阻塞段与右心房过近而无法测量外,余４６例BCS横断面图像测量IVC近心段的横径平均为（１７．５７±３．９３）mm,纵径平均为（２５．０９±６．０９）mm。使用直径３０mm的大球囊导管扩张IVC后造影全部显示血流通畅,无一例破裂。术后１周彩超发现右侧少量胸腔积液２例,心包积液４例,未见腹腔出血。结论使用直径３０mm大球囊导管扩张治疗IVC阻塞型BCS安全可行。     

心血管造影及超声检查在小儿先天性心脏病介入治疗中的联合应用研究

目的评价心血管造影与超声检查在小儿先天性心脏病介入治疗中的应用价值及其限度，探讨联合应用的指导意义。方法１６２例经超声筛选的先天性心脏病患儿，其中室间隔缺损（VSD）５０例、动脉导管未闭（PDA）９６例、肺动脉狭窄（PS）１６例，介入术前均行心血管造影检查并测量缺损和狭窄处直径，重复超声检查，用配对t检验统计方法比较其差异；介入术后重复造影及超声检查评价封堵器位置、球囊扩张效果等。结果心血管造影及超声检查对小儿先天性心脏病均能明确诊断，对其部位、形态均能良好显示。上述两种方法测量５０例VSD缺损直径分别为（４．９３±２．７３）mm和（５．６６±２．７７）mm，两者差异无统计学意义（P＞０．０５）；测量９６例PDA最窄处直径分别为（３．２２±１．４５）mm和（３．９６±１．４２）mm，两者差异有统计学意义（P＜０．０５）；测量１６例PS瓣环直径，分别为（１６．１６±４．２６）mm和（１７．９４±５．５０）mm，两者差异无统计学意义（P＞０．０５）。VSD术中超声监测发现封堵器影响瓣膜开闭者９例，并经超声监测下重新调整位置直至正常。VSD及PDA介入术后造影共发现残余细小分流７例，２４h后超声检查残余细小分流全部消失。１６例PS患儿经球囊扩张后，右室－肺动脉压差均较术前下降超过５０％，达到临床治疗标准。１６２例中除３例外均成功施行介入治疗。结论在小儿先天性心脏病介入治疗中病变直径测量与封堵器选择需以造影检查为标准，但在介入术前病例筛选及术后疗效评价中，超声检查更具优势。     

球囊扩张成形术在小儿食管狭窄中的应用

【摘要】 目的　 总结球囊扩张成形术在小儿食管狭窄治疗中的应用,评价其安全性、有效性和影响疗效的因素。方法 回顾性分析 30例小儿食管狭窄行球囊扩张成形术的临床资料,其中先天性食管闭锁术后吻合口狭窄 20例,先天性食管下段狭窄 5例,误服强碱食管腐蚀伤后狭窄 5例。按扩张次数将患儿分为3组,A 组18例,行 1次球囊扩张,均为先天性食管闭锁术后吻合口狭窄患儿;B 组 7例,行 2 ～ 3次球囊扩张,主要为先天性食管狭窄和先天性食管闭锁术后吻合口狭窄患儿;C 组 5例,行4 ～ 6次球囊扩张,为食管化学性烧灼伤患儿。扩张前行上消化道造影检查,明确病灶部位及狭窄程度,分别使用不同规格球囊进行扩张;扩张后复查造影进行对照分析了解扩张效果,分析各组间病因、食管狭窄长度和狭窄食管直径对扩张效果的影响。结果 30例患儿共接受62次扩张,平均每例扩张2.1次（1 ~ 6次）。27例患儿扩张后呕吐症状明显改善,体重明显增加;3例化学性烧灼伤患儿疗效不佳,转而进行手术治疗,全部患儿未发生穿孔、呕血或黑便等并发症。A、B、C 3组患儿食管扩张前狭窄段平均直径分别为:4.0 mm（3.0 ～ 5.0）,4.3 mm（2.5 ～ 6.0）和4.4 mm（4.0 ～ 5.0）,平均狭窄段长度分别为（1.18 ± 0.59）cm,（1.53 ± 0.49）cm和（7.50 ± 2.89）cm。3组扩张成功率分别为18/18、7/7和2/5。C组患儿食管狭窄段长度显著大于其他两组,P < 0.05。C 组患儿扩张有效率显著低于 A、B 组（P < 0.01）。结论 球囊扩张成形术治疗小儿食管狭窄操作简便,安全有效,可以有效地解除患儿的食管狭窄症状,是治疗小儿食管狭窄的首选方法。食管闭锁术后吻合口狭窄和先天性食管狭窄患儿扩张有效率高;化学性烧灼伤患儿需要反复多次扩张和再手术。
     

先天性食管闭锁手术后吻合口狭窄的介入治疗

目的报道13例先天性食管闭锁术后食管吻合口狭窄婴儿使用球囊扩张术治疗.方法13例患儿均为食管闭锁术后吻合口狭窄,年龄为3～10个月,球囊扩张前均先行食管吞钡检查,显示狭窄段内径仅1～3 mm.采用球囊导管分次扩张.所用球囊直径6～12 mm.结果每例经2～3次扩张,13例共进行球囊扩张30次,扩张后疗效明显,保持临床无症状期6～30个月,无食管穿孔并发症.结论球囊扩张术简单、安全、有效,为婴儿先天性食管闭锁手术后吻合口狭窄的首选疗法.     

食管吻合口狭窄气囊导管扩张术与放置内支架疗效对比

【摘要】 目的 对比评价食管贲门癌术后吻合口狭窄单纯气囊导管扩张术与辅以食管支架置入术的治疗效果。方法 两种病例共１０３例吻合口狭窄均作了气囊导管扩张术，其中７９例作单纯气囊导管扩张术，２４例作气囊导管扩张术辅以支架置入术（５例为裸支架，１９例为覆膜支架）。 结果 全部１０３例作单纯气囊导管扩张术后经４ ～ ３８个月随访观察，有效者７９例，占７６．７％；另２４例扩张无效者辅以放置食管支架，经４　～　３８个月随访，有效者１７例，有效率７０．８％；与单纯作气囊导管扩张术比较差异无统计学意义（χ２ ＝ ０．３６，Ｐ ＞ ０．０５ ）。 结论 食管贲门癌术后吻合口狭窄，应以气囊导管扩张术作为首选的治疗方法，气囊导管扩张无效者再考虑辅以放置食管支架作为治疗的补救措施。
     

一级微铜圈肾动脉栓塞的实验研究

【摘要】 目的 评价一级微铜圈在动物体内的栓塞性能和生物相容性。方法 用直径0.1 ～ 0.23 mm导电用铜丝（纯度99.9%）制成直径0.48 ～ 0.74 mm的一级微铜圈,经3 F微导管释放栓塞兔肾动脉末梢支,于栓塞术后不同时间观察血管闭塞情况和病理学改变,同时对实验动物栓塞前后的实验室检查指标进行比较。结果 栓塞术后3 d,1、2、4、6和 12周,动脉造影血管管腔闭塞时可见到血栓形成。栓塞后4周, 组织学检查均可见小动脉内微球,动脉周围有炎性反应,并可见肾实质梗死灶;栓塞术后,血清铜离子术后2周内较术前升高,差异有统计学意义（P < 0.05）,术后4周与术前比较,差异无统计学意义（P > 0.05）;肝、肾功能2周后恢复至术前水平。结论 自制一级微铜圈具有明确的栓塞效果和良好的生物相容性。

     

兔 VX２ 肝种植肿瘤模型制作的完善及综合影像学评价

目的进一步完善兔VX２肝种植肿瘤模型的制作，比较种植肿瘤的CT、MRI及DSA影像表现，评价各影像检查对瘤体显示的优越性。方法实验动物为新西兰大白兔（前期实验１２只，后期实验２４只），采用动物后肢皮下注射接种传代保存瘤种。模型前期制作采用包埋法接种，后期采用针头注入法接种于兔肝左叶，并于术前１d及术后１、３d、１、２周检查肝肾功能的动态变化情况。接种２周后行CT、MR成像，随后行经股动脉肝动脉超选择DSA及纳米磁性粒子介入治疗。结果前期实验肿瘤种植成功率６６．７％，后期实验种植成功率１００％。术后ALT、AST有一过性增高，无统计学意义；BUN、Cr无明显变化。术后CT平扫肿瘤为略低密度病灶，强化不明显，境界清晰；MR平扫呈长T１、长T２信号；EPI序列T２WI呈略高信号影；DWI成像见高亮信号影，显示清晰；介入术中DSA造影可见肝左叶孤立的丰富血管肿瘤，供血动脉增粗，经超选择注入纳米磁性粒子，肿瘤内密度明显增高。结论兔VX２肝种植肿瘤模型是介入治疗实验研究理想的动物模型。VX２瘤粒针头注入法较包埋法成功率更高，其建立过程对兔肝肾功能无明显影响。CT平扫增强，MR平扫，EPI序列及DWI成像对于肿瘤的影像评价互有优势，EPI及DWI成像可更灵敏地显示肿瘤，DSA可清晰地显示肿瘤的供血及肝内有无转移。     

食管良性狭窄介入治疗方法探讨和再狭窄原因分析

目的:探讨食管良性狭窄有效的介入治疗方法,并分析发生食管再狭窄的主要原因。对象与方法:50例食管良性狭窄病人,其中35例采用X线下不同型号球囊导管扩张治疗。另15例在X线下置入食管内支架。所有病人治疗前皆有不同程度的吞咽困难。结果:35例食管良性狭窄共进行67次球囊扩张,平均1.9次。摄食能力术前后分级和术后症状复发时分别为1.43±0.80级.4.88±0.83级和1.71±0.82级。食管最狭窄处直径术前后和症状复发时分别为4.02±2.09mm.9.86±2.98mm和4.52±1.95mm。症状缓解1～12月,平均3.14±2.37个月。15例食管良性狭窄支架置入术技术成功率100％。支架置入前后摄食能力分级为0.8±0.84级和3.8±0.45级,食管管腔内径术前后为3.6±1.34mm.18.4±0.89mm。术后随访10天～30月,平均10.5个月。发生再狭窄3例。结论:食管狭窄介入治疗是提高食管良性狭窄治疗短期疗效的首选方法。食管再狭窄主要是肉芽组织增生所致。     

Effect of fuel injection timing and injection pressure on performance in a hydrogen direct injection engine

The in-cylinder hydrogen fuel injection method (diesel engine) induces air during the intake stroke and injects hydrogen gas directly into the cylinder during the compression stroke. Fundamentally, because hydrogen gas does not exist in the intake pipe, backfire, which is the most significant challenge to increasing the torque of the hydrogen port fuel injection engine, does not occur. In this study, using the gasoline fuel injector of a gasoline direct-injection engine for passenger vehicles, hydrogen fuel was injected at high pressures of 5 MPa and 7 MPa into the cylinder, and the effects of the fuel injection timing, including the injection pressure on the output performance and efficiency of the engine, were investigated. Strategies for maximizing engine output performance were analyzed.The fuel injection timing was retarded from before top dead center (BTDC) 350 crank angle degrees (CAD) toward top dead center (TDC). The minimum increase in the best torque ignition timing improved, and the efficiency and excess air ratio increased, resulting in an increase in torque and decrease in NO_x emissions. However, the retardation of the fuel injection timing is limited by an increase in the in-cylinder pressure. By increasing the fuel injection pressure, the torque performance can be improved by further retarding the fuel injection timing or increasing the fuel injection period. The maximum torque of 142.7 Nm is achieved when burning under rich conditions at the stoichiometric air-fuel ratio.     

Effects of second hydrogen direct injection proportion and injection timing on combustion and emission characteristics of hydrogen/n-butanol combined injection engine

Hydrogen and n-butanol are superior alternative fuels for SI engines, which show high potential in improving the combustion and emission characteristics of internal combustion engines. However, both still have disadvantages when applied individually. N-butanol fuel has poor evaporative atomization properties and high latent heat of vaporization. Burning n-butanol fuel alone can lead to incomplete combustion and lower temperature in the cylinder. Hydrogen is not easily stored and transported, and the engine is prone to backfire or detonation only using hydrogen. Therefore, this paper investigates the effects of hydrogen direct injection strategies on the combustion and emission characteristics of n-butanol/hydrogen dual-fuel engines based on n-butanol port injection/split hydrogen direct injection mode and the synergistic optimization of their characteristics. The energy of hydrogen is 20% of the total energy of the fuel in the cylinder. The experimental results show that a balance between dynamics and emission characteristics can be found using split hydrogen direct injection. Compared with the second hydrogen injection proportion (IP2) = 0, the split hydrogen direct injection can promote the formation of a stable flame kernel, shorten the flame development period and rapid combustion period, and reduce the cyclic variation. When the IP2 is 25%, 50% and 75%, the engine torque increases by 0.14%, 1.50% and 3.00% and the maximum in-cylinder pressure increases by 1.9%, 2.3% and 0.6% respectively. Compared with IP2 = 100%, HC emissions are reduced by 7.8%, 15.4% and 24.7% and NOx emissions are reduced by 16.4%, 13.8% and 7.9% respectively, when the IP2 is 25%, 50% and 75%. As second hydrogen injection timing (IT2) is advanced, CA0-10 and CA10-90 show a decreasing and then increasing trend. The maximum in-cylinder pressure rises and falls, and the engine torque gradually decreases. The CO emissions show a trend of decreasing and remaining constant. However, the trends of HC emissions and NOx emissions with IT2 are not consistent at different IP2. Considering the engine's dynamics and emission characteristics, the first hydrogen injection proportion (IP1) = 25% plus first hydrogen injection timing (IT1) = 240°CA BTDC combined with IP2 = 75% plus IT2 = 105°CA BTDC is the superior split hydrogen direct injection strategy.     

聚桂醇注射液与无水乙醇超声引导下治疗肝血管瘤疗效比较

【摘要】 目的 探讨聚桂醇注射液与无水乙醇超声引导下经皮穿刺治疗肝血管瘤的临床疗效与安全性。方法 60例肝血管瘤患者随机分为无水乙醇组和聚桂醇组,每组30例,对比两组患者临床疗效及不良反应发生率。结果 每组临床疗效对比差异无统计学意义（P=0.489,P＞0.05）,无水乙醇组不良反应发生率明显高于聚桂醇组,差异有统计学意义（χ2=5.963,P=0.03,P＜0.05）。结论 超声引导下经皮穿刺聚桂醇注射液与无水乙醇治疗肝血管瘤临床疗效相当,但聚桂醇组不良反应少,疼痛率低,患者耐受性好,此治疗方法值得临床推广应用。
     

根据喷油压力波形特征判断燃油喷射装置故障部位

通过ZB-2型柴油机燃油喷射系统故障诊断仪(即柴油机燃油压力波检测仪)对DF4型机车柴油机燃油压力波的检测,在对大量检测事例进行跟踪、统计、分析的基础上,揭示出燃油压力波的检测波形与该缸喷射装置质量状态的对应关系,并据此确定故障部位,为故障处理提供参考.     

Energy and exergy analysis of a combined injection engine using gasoline port injection coupled with gasoline or hydrogen direct injection under lean-burn conditions

Hydrogen is considered to be a suitable supplementary fuel for Spark Ignition (SI) engines. The energy and exergy analysis of engines is important to provide theoretical fundaments for the improvement of energy and exergy efficiency. However, few studies on the energy and exergy balance of the engine working under Hydrogen Direct Injection (HDI) plus Gasoline Port Injection (GPI) mode under lean-burn conditions are reported. In this paper, the effects of two different modes on the energy and exergy balance of a SI engine working under lean-burn conditions are presented. Two different modes (GPI + GDI and GPI + HDI), five gasoline and hydrogen direct injection fractions (0, 5%, 10%, 15%, 20%), and five excess air ratios (1, 1.1, 1.2, 1.3, 1.4) are studied. The results show that the cooling water takes the 39.40% of the fuel energy on average under GPI + GDI mode under lean-burn conditions, and the value is 40.70% for GPI + HDI mode. The exergy destruction occupies the 56.12% of the fuel exergy on average under GPI + GDI mode under lean-burn conditions, and the value is 54.89% for GPI + HDI mode. The brake thermal efficiency and exergy efficiency of the engine can be improved by 0.29% and 0.31% at the excess air ratio of 1.1 under GPI + GDI mode on average, and the average values are 0.56% and 0.71% for GPI + HDI mode.     

Influence of injection parameters and mold materials on mechanical properties of ABS in plastic injection molding

This study optimized effect of injection parameters such as melt temperature, packing pressure, cooling time and injection pressure on the mechanical properties of Acrylonitrile–Butadiene–Styrene (ABS) moldings. Mold materials having two different thermal conductivities, 191 W/mK for aluminum 2000 series and 50 W/mK for AISI 1020 at 25 °C were selected to use in experimental studies. Taguchi's L₉(3⁴) orthogonal array design was employed for the experimental plan. Mechanical properties of ABS specimens such as elasticity module, tensile strength and tensile strain at yield, tensile strain at break, flexural modules and izod impact strength (notched) were measured by using some test methods. Signal to noise ratio for mechanical properties of ABS using the Taguchi method was calculated and effect of the parameters on mechanical properties was determined using the analysis of variance. Linear mechanical models were also created by using regression analysis.     

Impact of physical properties of biodiesel on the injection process in a common-rail direct injection system

This paper presents the influence of biodiesel fuel properties on the injection mass flow rate of a diesel common-rail injection system. Simulations are first performed with ISO 4113 diesel fuel on a four-cylinder common-rail system to evaluate a single and triple injection strategies. For each injection strategy, the impact of modifying a single fuel property at a time is evaluated so as to quantify its influence on the injection process. The results show that fuel density is the main property that affects the injection process, such as total mass injected and pressure wave in the common-rail system. The fuel’s viscosity and bulk modulus also influence, but to a lessen degree, the mass flow rate of the injector notably during multiple injection strategies as individual properties change the fuel’s dampening property and friction coefficient.     

Effect of mixture strength and injection timing on combustion characteristics of a direct injection hydrogen-fueled engine

An experimental investigation was performed to characterize the hydrogen combustion in a spark-ignition direct-injection engine. It was focused on the effects of mixture strength and injection timing on the characteristics of hydrogen combustion. For this purpose, the practical tests were carried out on an experimental test rig. It is originally designed for optimization of the direct-injection natural-gas engine. The experimental test-rig results comprised the traces for the in-cylinder pressure, mass fraction burned, and heat release rate under the different operation conditions. The results obtained show that the richer mixture condition produced higher pressure trends at all tested points. Besides that, it exhibited a faster rate of increase in combustion rate due to the increase of flame speed. However, the combustion characteristics deteriorated due to the lack of mixture stratification with earlier injection timing. It is concluded that direct-injection timing is essential to achieve better combustion performance. Moreover, retarding the spark ignition timing is also crucial to avoid abnormal combustion in the case of a richer mixture and early start on injection.