水稻谷粒的挤压力学性能研究

水稻谷粒的损伤与破碎除与其所受内、外力的作用有关,还与其本身的力学性能有关。通过对水稻谷粒的挤压力学试验,测得了其力-位移曲线,分析了水稻谷粒的挤压破碎过程。破坏力和破坏能是水稻谷粒力学特性的两个重要指标。试验研究了稻谷的品种、成熟程度、后熟作用和谷壳对水稻谷粒力学性能的影响。比较了有壳、无壳谷粒的破坏力与破坏能,分析了谷壳对谷粒力-位移曲线及刚度的影响。指出谷壳在降低谷粒收获、加工、储运中的损伤程度具有重要作用。     

电涡流缓速器对车辆制动稳定性的影响分析

修正车辆理想制动力分配曲线使之适用于装用电涡流缓速器的车辆,对装用电涡流缓速器的车辆制动稳定性进行了定性分析,并且提出了增加前后制动器制动力的分配系数来提高装用缓速器后的车辆制动稳定性的技术措施.对给定参数的车辆的定量分析表明,提出的技术措施能扩大车辆同步附着系数的范围,降低车辆后轮先抱死的可能性,提高车辆的制动稳定性.     

Effect of magnitude and direction of force on laryngeal abduction: Implications for the nerve‐muscle pedicle graft technique

Reasons for performing study: The nerve‐muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Hypothesis: The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods: Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead‐weight force generator applied a force of 0–14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70° angles. The rima glottis was photographed digitally 1 min after each force had been applied. Distances between biomarkers (Lines 1–4) and right to left angle quotient (RLQ) were used to assess the degree of left arytenoid abduction. Results: Increasing force from 0–14.7 N progressively and significantly increased the length of all lines and RLQ, indicating abduction. Furthermore, there was a significant interaction between force and angles. Applying forces of 7.84 N or greater (Lines 2–4 and RLQ) or 11.76 N or greater (Line 1) at angles 0, 10, 20 and 30° resulted in significantly greater abduction than applying the same forces at 40, 50, 60 and 70°. Angles of 0–30° correspond with the direction of pull exerted by the lateral compartment of the CAD muscle. Conclusion: In RLN, nerve‐muscle pedicle grafts should be placed preferentially in the lateral rather than in the medial compartment of the CAD muscle. Potential relevance: The information presented can be used to assist surgeons in the planning and application of the nerve‐muscle pedicle graft procedure.     

不同采收期艾蒿水提物体外抗氧化活性的研究

试验研究了不同采收期艾蒿水提物主要的生物活性成分及其体外抗氧化活性。以料液比(艾蒿:水)1:15(g/mL),70℃水浴4 h制备艾蒿水提物,测定不同采收期艾蒿水提物中多糖、黄酮和多酚的含量,并测定艾蒿提取物对Fe3+的还原力及其对DPPH自由基和羟基自由基的清除力。结果发现,8月份艾蒿水提物中多糖、黄酮和多酚的含量最高,体外抗氧化能力也最强,而6、7月份和9月份艾蒿水提物的体外抗氧化能力较低。研究表明,艾蒿水提物作为一种潜在的天然抗氧化剂资源,其主要的生物活性成分和抗氧化活性受采收期影响而存在一定的差异,与其他月份相比,8月份收割的艾蒿更适宜制备艾蒿水提物。     

不同裂荚特性箭筈豌豆裂荚力数字化评价

以美国种质资源库(NPGS)提供的541份箭筈豌豆(Vicia sativa)种质为基础,经过连续3年裂荚率评价,共筛选出高、中、低裂荚种质33份。以这33份箭筈豌豆种质作为本研究的试验材料,利用艾德堡HP-50数显推拉力计结合裂荚率对箭筈豌豆荚果水平放置时的裂荚机械力和垂直放置时的裂荚机械力进行分析,为选育箭筈豌豆抗裂荚种质提供精确、快速的评价方法。结果显示,1)箭筈豌豆高裂荚种质荚果裂荚机械力极显著低于低裂荚种质荚果裂荚机械力(P0.01)。2)箭筈豌豆荚果水平放置时的裂荚机械力极显著低于垂直放置时的裂荚机械力(P0.01)。3)箭筈豌豆荚果在水平放置下裂荚机械力大于9.286N的为低裂荚种质,裂荚机械力小于2.163N的为高裂荚种质。研究表明,利用推拉力计测试水平放置的箭筈豌豆荚果裂荚机械力可准确反映箭筈豌豆不同种质的裂荚特性,并为箭筈豌豆裂荚特性的标准化测定提供了重要的参考依据。     

华北山区草地资源及其生产力的研究

华北山区位于温带——暖温带，东经１０７°～１２３°，北纬３５°～４３°。包括山东丘陵区，太行山区，冀北辽西山地区，阴山山地区四部分。该区属于农牧业交错区，农业、牧业（农区牧业和草地牧业）、林业十分发达，并且在迅速发展。华北山区是我国小麦、玉米和杂粮的主要产区。草地类型多样，饲草料丰富，又是养牛业、养羊业、养猪业相当发达的地区。经统计，华北山区总人口为５６２９万，总土地面积３５４５万ｈａ，天然草地总面积为１５８８．９１万ｈａ，占土地总面积的４４．８２％，人均草地０．２８２３ｈａ。各个区的草地类型不同，生产力差异显著（ｐ＜０．０１）。     

Force plate analysis before and after dorsal decompression for treatment of degenerative lumbosacral stenosis in dogs

OBJECTIVE: Using force plate analysis (FPA), determine ground reaction forces in dogs with degenerative lumbosacral stenosis (DLS) and evaluate the effects of lumbosacral decompressive surgery. STUDY DESIGN: Prospective clinical study. ANIMALS: Twelve dogs with DLS. METHODS: DLS was diagnosed by clinical signs, radiography, computed tomography, and/or magnetic resonance imaging. FPA was performed before surgery, and 3 days, 6 weeks, and 6 months after surgery. The mean peak braking (Fy+), peak propulsive (Fy-), and peak vertical (Fz+) forces of 8 consecutive strides were determined. The ratio between the total Fy- of the pelvic limbs and the total Fy- of the thoracic limbs (P/TFy-), reflecting the distribution of Fy-, was analyzed to evaluate any changes in locomotion pattern postoperatively. Ground reaction force data for DLS dogs were compared with data derived from 24 healthy dogs (control). RESULTS: In dogs with DLS, the propulsive forces (Fy-) of the pelvic limbs were significantly smaller than those of controls. P/TFy- was significantly smaller in dogs with DLS than in control dogs, and increased during the follow-up period, reaching normal values 6 months after surgery. CONCLUSIONS: Cauda equina compression in dogs with DLS decreases the propulsive force of the pelvic limbs and surgical treatment restores the propulsive force of the pelvic limbs in a 6-month period. CLINICAL RELEVANCE: In dogs with DLS, FPA is an effective method in evaluating the response to surgical treatment. Normal propulsive force in the pelvic limbs was restored during 6 months after decompressive surgery.     

Comparative therapeutic efficacy and safety of type-II collagen (UC-II), glucosamine and chondroitin in arthritic dogs: pain evaluation by ground force plate

The investigation was conducted on client-owned moderately arthritic dogs with two objectives: (i) to evaluate therapeutic efficacy of type-II collagen (UC-II) alone or in combination with glucosamine hydrochloride (GLU) and chondroitin sulphate (CHO), and (ii) to determine their tolerability and safety. Dogs in four groups (n = 7-10), were treated daily for a period of 150 days with placebo (Group-I), 10 mg active UC-II (Group-II), 2000 mg GLU + 1600 mg CHO (Group-III), and UC-II + GLU + CHO (Group-IV). On a monthly basis, dogs were evaluated for observational pain (overall pain, pain upon limb manipulation, and pain after physical exertion) using different numeric scales. Pain level was also measured objectively using piezoelectric sensor-based GFP for peak vertical force and impulse area. Dogs were also examined every month for physical, hepatic (ALP, ALT and bilirubin) and renal (BUN and creatinine) functions. Based on observations, significant (p < 0.05) reduction in pain was noted in Group-II, III, and IV dogs. Using GFP, significant increases in peak vertical force (N/kg body wt) and impulse area (N s/kg body wt), indicative of a decrease in arthritis associated pain, were observed in Group-II dogs only. None of the dogs in any group showed changes in physical, hepatic or renal functions. In conclusion, based on GFP data, moderately arthritic dogs treated with UC-II (10 mg) showed a marked reduction in arthritic pain with maximum improvement by day 150. UC-II, GLU and CHO operate through different mechanisms of action, and were well tolerated over a period of 150 days.     

四川白鹅对花生藤营养物质表观消化率研究

我国花生种植面积世界第一,但花生藤却没有得到充分利用.因此本试验通过研究四川白鹅对花生藤营养物质的表观消化率,确定其在四川白鹅日粮中的合理添加量,为优化日粮配方和花生藤的合理利用提供理论依据和数据参考.试验随机选取18周龄、(3.5±0.25)kg四川白鹅公鹅12只,采用强饲法(全收粪法),每只试验鹅用强饲器强饲40 ...     

棉秆剪切力与营养成分含量之间的相关关系

本试验旨在研究棉秆剪切力与营养成分含量之间的相关关系。将棉秆按照近地面1/3(下1/3)、中部1/3(中1/3)和上部1/3(上1/3)切为3段,测定各段的质量和长度,计算线性密度;测定茎秆和侧茎的剪切力及主要营养成分的含量。结果表明:棉秆线性密度及直径由上至下逐渐升高,3段之间差异显著(P0.05);全株棉秆粗蛋白质含量为8.78%;中性洗涤纤维在茎秆下1/3含量(62.54%)最高,棉叶中含量(35.51%)最低;棉秆茎秆中粗蛋白质及粗灰分含量与剪切力间呈负相关关系(P0.001);干物质、中性洗涤纤维、酸性洗涤纤维及半纤维素含量与剪切力呈正相关关系(P0.001)。棉秆不同部位中,剪切力大小主要受其直径和营养成分含量的影响,棉秆的剪切力与营养成分含量之间具有较强的线性关系。