The effects of maxillary nerve block,ethmoidal nerve block and their combination on cardiopulmonary responses to nasal stimulation in anesthetized Beagle dogs

ObjectiveTo describe an approach for ethmoidal nerve block (E_BLOCK) and to compare the effects of a maxillary nerve block (M_BLOCK), E_BLOCK and their combination (M-E_BLOCK) on heart rate (HR), systolic (SAP), mean (MAP), diastolic (DAP) arterial pressures and respiratory rate (f_R) during nasal stimulation in dogs.Study designProspective, blinded, randomized, crossover placebo-controlled study.AnimalsBeagle dogs (five cadavers, nine live dogs), with a median (interquartile range) weight of 10.5 (10.3–11.0) kg.MethodsThe accuracy of iohexol injections (each 1 mL) at the maxillary and ethmoidal foramina in cadavers was evaluated using computed tomography. Then, anesthetized dogs were administered four bilateral treatments separated by 1 week, saline or 2% lidocaine 1 mL per injection: injections of saline at the maxillary and ethmoidal foramina (Control), injections of lidocaine at the maxillary foramina and saline at the ethmoidal foramina (M_BLOCK), injections of saline at the maxillary foramina and lidocaine at the ethmoidal foramina (E_BLOCK) and injections of lidocaine at all foramina (M-E_BLOCK). The ventral nasal meatus was bilaterally stimulated using cotton swabs, and HR, SAP, MAP, DAP and f_R were continuously recorded. Values for each variable were compared before and after stimulation using Wilcoxon signed-rank test. Changes in variables among treatments were analyzed using Mann–Whitney U and Kruskal–Wallis tests (p ≤ 0.05).ResultsComputed tomography revealed iohexol distribution around the openings of the target foramina in all cadavers. In living dogs, HR, SAP, MAP, DAP and f_R significantly increased after stimulation within each treatment (p < 0.03). Physiologic responses were significantly attenuated, but not absent, in the M-E_BLOCK [HR (p = 0.019), SAP, MAP, DAP and f_R (all p ≤ 0.001)] compared with those in the Control.Conclusions and clinical relevanceConcurrent injections of lidocaine at the maxillary and ethmoidal foramina attenuated HR, arterial pressure and f_R responses to nasal stimulation in Beagle dogs.     

Mechanical performance of a screw-type veterinary suture anchor subjected to single load to failure and cyclic loads

OBJECTIVE: To characterize the mechanical performance of a veterinary bone anchor under static and cyclic loads. STUDY DESIGN: Mechanical testing study. ANIMALS: Cadaveric canine humeri. METHODS: Humeri (6 pairs) were collected from skeletally mature dogs (mean [+/-SD] age, 17.2+/-2.1 months; weight, 20.8+/-1.5 kg). Bone anchors were inserted in the proximal metaphysis using nylon, and were longitudinally extracted. For the opposite humerus, anchors were subjected to longitudinal cyclic load (50% of the load at failure of their pair) for 1200 cycles then longitudinally loaded to failure. Anchors were then installed in a similar and adjacent area of these 2(nd) humeri with nylon and cyclically tested perpendicular to the axis of anchor insertion (100% of the longitudinal holding power of their pair) for 1200 cycles, then perpendicularly loaded to failure. Paired t-tests were used to compare holding power before and after longitudinal cyclic testing. RESULTS: Longitudinal holding power of the screw-type anchor in the proximal humerus was 385+/-30 N. Anchor pullout was the only mode of failure. Anchors in the paired humeri did not fail after 1200 cycles of 50% longitudinal loading, and post-cycle holding strength was not different (335+/-87 N; P=.32). Perpendicularly loaded anchors did not fail after 1200 cycles of 100% of opposite longitudinal holding strength, and had post-cycle perpendicular holding strengths of 514+/-72 N. Suture breakage was the mode of failure. CLINICAL RELEVANCE: Bone anchor holding strength is dependent on orientation of suture load. Screw-type bone anchor holding strength was not affected by longitudinal cyclic loading, and holding strengths of approximately 385 N can be expected in metaphyseal bone of large-breed mature dogs. Perpendicularly loaded anchors have higher failure loads, and holding strength of approximately 514 N can be expected in metaphyseal bone of the proximal humerus.     

鸡蛋静态力学特性的研究

通过静态压缩试验研究了不同蛋大小、蛋形指数及鸡蛋横压、竖压、大小端受压情况下鸡蛋的破坏形式和力学特性;探讨了缓冲材料对鸡蛋抗压强度的影响规律;同时进行了冷藏鸡蛋的抗压力学性能试验研究。试验结果表明:蛋形指数、鸡蛋大小、鸡蛋大小端等物理参数对抗压强度均有影响,其中以蛋形指数、缓冲材料的影响显著,鸡蛋大头朝上竖放可减少破损,冷藏提高了鸡蛋的抗变形能力。     

水稻钵苗移栽下坠高度及导管摩擦对栽深的影响

该文通过对钵苗落差高度与栽植深度关系和秧苗钵体相对于导管不同材料的动、静摩擦系数的试验研究,为导管式分秧栽植机构的设计提供理论依据.试验结果表明:水稻钵体秧苗的栽植深度随钵苗落差高度的增加而增加;对一般水田土壤类型,在整地质量满足农艺要求的条件下,钵苗落差高度在0.75～1.50 m范围内时,秧苗栽植深度为4.8～12.5 mm,可以满足秧苗栽深的农艺要求;秧苗钵体相对于钢板和塑料板的摩擦系数变化不大,受秧苗钵体相对湿度的影响较大,且随钵体相对湿度的增加而增加,在相对湿度为80%左右时达到最大值;一般情况下,在机器设计中,可取摩擦系数的最大值为0.7,摩擦角为35°.     

机电设备安装工程造价的有效控制与管理措施分析探讨

文章通过对建筑工程造价的分析,介绍了机电工程安装的特点,并分析了影响机电设备安装工程造价的因素,总结出相对的控制方法和管理措施。     

无瓣海桑木材性质及加工利用的研究

对采自广东省雷州市红树林内无瓣海桑的木材物理力学性质进行研究。结果表明,无瓣海桑木材材质轻软、干缩性能和强度中等、冲击韧性较低,可用于普通家具、一般的建筑用材、普通包装材料、人造板,不适宜做地板、高档家具等。     

定量机械通风对华南地区哺乳猪舍环境和母猪繁殖性能的影响

为探究定量机械通风对华南地区哺乳猪舍环境和母猪繁殖性能的影响,该研究实测并比较了该地区冬季自然通风和定量机械通风2种模式对两广小花猪哺乳猪舍的环境温度、湿度、二氧化碳、氨气浓度和母猪繁殖性能、呼吸频率、直肠温度等指标的影响。结果表明,在夜晚期间,自然通风哺乳舍的二氧化碳和氨气浓度分别为（817.16±25.28）和（7.88±0.34）mg/m3,均显著高于定量机械通风哺乳舍的（645.71±9.49）和（5.59±0.14）mg/m3（P＜0.01）;自然通风哺乳舍的全天二氧化碳和氨气浓度分别为（707.34±20.42）和（6.63±0.27）mg/m3,均显著高于定量机械通风哺乳舍的（583.25±10.06）和（4.81±0.13）mg/m3（P＜0.01）。定量机械通风模式下的出生活仔猪数为（12.50±0.55）头,与自然通风模式的（11.13±0.66）头相比具有升高的趋势（P=0.08）;定量机械通风模式的仔猪平均日增质量为（146±40）g,与自然通风模式的（133±70）g相比也具有增加的趋势（P=0.09）。然而,与定量机械通风相比,自然通风模式下的母猪平均日体质量损失（P=0.06）和平均日背膘损失（P=0.08）均有降低的趋势。此外,在哺乳第21天,自然通风模式的母猪呼吸频率为（69.50±3.85）次/min,显著高于定量机械通风模式的（57.29±1.54）次/min（P＜0.05）。综上,定量机械通风模式可对冬季华南地区两广小花猪哺乳母猪舍内空气质量有明显改善,提高母猪繁殖性能。     

四倍体酸枣组培苗移栽研究

以四倍体酸枣生根组培苗为试材,研究炼苗天数、基质种类、空气相对湿度、组培苗高度、根条数及移栽时间对组培苗移栽成活率和生长的影响。结果表明：移栽应在4月底至6月进行,在此时期选择高度大于5 cm,根7条以上的组培苗,经炼苗3天,移栽至纯蛭石或珍珠岩与土（1:1）或蛭石与土（1:1）中,移栽前期保持空气相对湿度在90%以上,移栽成活率可达70%以上。     

Human Simulated Intelligence Motion Control for Three-link Acrobot on Horizontal Bar

The design of multi-controller and multi-mode control law is presented for the three-link Acrobot on horizontal bar by employing Human simulated intelligent control method based on sensory-motor Schema.Imitated the characteristics of gymnast's swing-up and handstand movement,the control process of robot is divided by six sequence phase.Then the sensory cell and motor cell and the group of sensory-motor schema is designed based on the analysis of quality-quantity combination.The simulation results show that the controller ensures the gesture and the energy to the desired goal,farther more the motion control of giant swing backword is realized in the simulation.     

玉米种子的机械损伤对其发芽率的影响

玉米种子质量是决定玉米产量的重要因素.目前,由于我国没有生产专用种子玉米脱粒机,玉米种子的脱粒只能采用打击原理设计的普通脱粒机,对玉米籽粒伤害较大,从而影响了种子在田间的出苗率以及植株整个生长发育过程.为此,针对不同部位有机械损伤的玉米种子对其发芽率的影响进行了分析,进而为新型低损伤玉米种子脱粒机的研制提供作用部位与作用方向的参考.