BACKGROUND & AIMS: :The tectorial membrane (TM) is an extracellular matrix situated over the sensory cells of the cochlea. Its strategic location, together with the results of recent TM-specific mutation studies, suggests that it has an important role in the mechanism by which the cochlea transduces mechanical energy into neural excitation. A detailed characterization of TM mechanical properties is fundamental to understanding its role in cochlear mechanics. In this work, the mechanical properties of the TM are characterized in the radial and longitudinal directions using nano- and microindentation experiments conducted by using atomic force spectroscopy. We find that the stiffness in the main body region and in the spiral limbus attachment zone does not change significantly along the length of the cochlea. The main body of the TM is the softest region, whereas the spiral limbus attachment zone is stiffer, with the two areas having averaged Young's modulus values of 37 +/- 3 and 135 +/- 14 kPa, respectively. By contrast, we find that the stiffness of the TM in the region above the outer hair cells (OHCs) increases by one order of magnitude in the longitudinal direction, from 24 +/- 4 kPa in the apical region to 210 +/- 15 kPa at the basilar end of the TM. Scanning electron microscopy analysis shows differences in the collagen fiber arrangements in the OHC zone of the TM that correspond to the observed variations in mechanical properties. The longitudinal increase in TM stiffness is similar to that found for the OHC stereocilia, which supports the existence of mechanical coupling between these two structures.

背景与目标： : 盖膜 (TM) 是位于耳蜗感觉细胞上方的细胞外基质。它的战略位置以及最近的TM特异性突变研究的结果表明，它在耳蜗将机械能转换为神经兴奋的机制中具有重要作用。TM机械性能的详细表征对于理解其在耳蜗力学中的作用至关重要。在这项工作中，使用原子力光谱法进行的纳米和微压痕实验，在径向和纵向上表征了TM的机械性能。我们发现，主体区域和螺旋角膜缘附着区的刚度沿耳蜗的长度没有显着变化。TM的主体是最柔软的区域，而螺旋角膜缘附着区则更硬，两个区域的平均杨氏模量值分别为37 +/- 3和135 +/-14 kpa。相比之下，我们发现外毛细胞 (OHCs) 上方区域中TM的刚度在纵向方向上增加了一个数量级，从顶端区域的24/- 4 kPa增加到210/- 15 kPa在TM的基底端。扫描电子显微镜分析显示，TM的OHC区域中胶原纤维排列的差异与观察到的机械性能变化相对应。TM刚度的纵向增加与OHC立体纤毛相似，这支持了这两个结构之间存在机械耦合。

BACKGROUND & AIMS: :The aim of this study was to analyse the acting forces and moments induced by a special orthodontic appliance, the Pendulum K, for molar distalization in the transverse and sagittal planes. The purpose-designed test set-up (artificial maxilla with anchorage unit and two electrothermodynamic molars, an electronic measuring unit, a unit with force-moment sensor, an analogue/digital converter, and a data read-out unit) allowed simulation of in vivo conditions on the one hand and precise determination of the force systems on the other. The appliances investigated were three specimens of the Pendulum K. In vitro measurement of the resulting force systems revealed that the forces and moments in the transverse and sagittal planes remained almost constant over a 3 mm measuring increment when the distal screw was continuously activated (10 activations/mm). Without reactivation of the incorporated distal screw, however, a marked decline in the force systems was recorded. The Pendulum K allows translatory distalization of the upper molars and thus dental arch expansion, dispensing with the need for permanent teeth to be extracted, subject to a corresponding indication. This is achieved by continuous adjustment of an incorporated distal screw and by specific pre-activations of the Pendulum springs.

背景与目标： : 这项研究的目的是分析由特殊的正畸矫治器摆K引起的作用力和力矩，以在横向和矢状平面中使磨牙远侧。目的设计的测试装置 (带有锚固单元和两个电热磨牙的人造上颌骨，一个电子测量单元，一个带力-力矩传感器的单元，一个模拟/数字转换器，和数据读出单元) 一方面可以模拟体内条件，另一方面可以精确确定力系统。所研究的器具是摆锤K的三个样本。所得力系统的体外测量表明，当远端螺钉连续激活 (10个激活/mm) 时，在3毫米测量增量内，横向和矢状平面中的力和力矩几乎保持恒定。但是，如果不重新激活合并的远端螺钉，则记录到力系统明显下降。摆锤K允许上磨牙的平移远端化，从而使牙弓扩张，从而无需拔出恒牙，但要有相应的指示。这是通过连续调节结合的远端螺钉和通过摆簧的特定预激活来实现的。

BACKGROUND & AIMS: :The Angelchik prosthesis appears to be effective in preventing gastroesophageal reflux, although its precise mechanism of action remains controversial. In a unique in vitro model, 10 freshly harvested canine esophagogastric specimens were tested for their ability to remain competent against challenges of intragastric pressure under controlled conditions of intra-abdominal pressure, longitudinal esophageal tension, lower esophageal sphincter pressure and overall length and circumference of the cardia (measure of gastric dilatation). Competency of the specimen was assessed by stepwise variation in the overall length of the sphincter, while keeping constant intraabdominal pressure (20 cm H2O), intragastric pressure (20 cm H2O), esophageal tension (physiologic), lower esophageal sphincter pressure (15 cm H2O) and degree of gastric dilatation (3 cm). With each specimen serving as its own control, the effect produced by the application of an Angelchik prosthesis was evaluated. Results consistently demonstrated that at any lower esophageal sphincter length the percent of competency was increased when the prosthesis was applied (P < 0.01). The findings indicate that the Angelchik prosthesis controls reflux by preventing unfolding of the lower esophageal sphincter when challenged by intragastric pressure.

背景与目标： : 尽管其确切的作用机制仍存在争议，但Angelchik假体似乎可有效预防胃食管反流。在一个独特的体外模型中，测试了10个新鲜收获的犬食管胃标本在受控的腹内压力，纵向食管张力，食管下括约肌压力以及贲门的总长度和周长 (胃扩张的测量) 条件下仍能抵抗胃内压挑战的能力。通过括约肌总长度的逐步变化来评估标本的能力，同时保持恒定的腹内压力 (20厘米H2O)，胃内压力 (20厘米H2O)，食管张力 (生理学)，食管下括约肌压力 (15厘米H2O) 和胃扩张程度 (3厘米)。以每个标本为自己的对照，评估了应用Angelchik假体所产生的效果。结果一致表明，在任何下食管括约肌长度处，当应用假体时，能力百分比都会增加 (P <0.01)。研究结果表明，当受到胃内压的挑战时，Angelchik假体通过防止下食管括约肌的展开来控制反流。

BACKGROUND & AIMS: :Spherical pellets containing theophylline, calcium acetate and microcrystalline cellulose were extruded and spheronized, before being coated with six different pectins or alginates by interfacial complexation. The aim of this study was to discover the effect of the coatings on physico-mechanical properties that will be crucial in determining the pellets' utility as sustained release systems. An insoluble, smooth and uniformly thick coat of calcium polysaccharide was formed around the core pellets. A factorial experiment was designed to investigate the effect of pellet size and polysaccharide type and concentration on the entrapment efficiency, mechanical properties and other physical characteristics. Coated pellets were observed by scanning electron microscopy and, depending on the particular polysaccharide used, the dry coats were found to be 30-80 microm thick. The size of pellet, the type and concentration of polysaccharide influenced the yield of theophylline in the coated pellets. Although the mechanical properties of the pellets were improved by applying any of the gel coats, use of an alginate with a high content of guluronic acid or an amidated pectin coating gave the best results. This is probably because both of these have significant potential to form very stable cross-links within the gel coats.

背景与目标： : 将含有茶碱，醋酸钙和微晶纤维素的球形颗粒挤出并球形化，然后通过界面络合用六种不同的果胶或藻酸盐包被。这项研究的目的是发现涂层对物理机械性能的影响，这对于确定颗粒作为持续释放系统的效用至关重要。在核心颗粒周围形成不溶性，光滑且均匀厚的钙多糖涂层。设计了析因实验，以研究颗粒大小，多糖类型和浓度对包封效率，机械性能和其他物理特性的影响。通过扫描电子显微镜观察到包被的颗粒，根据所用的特定多糖，发现干涂层的厚度为30-80微米。颗粒的大小，多糖的类型和浓度影响包衣颗粒中茶碱的产量。尽管通过施加任何凝胶涂层可以改善颗粒的机械性能，但使用具有高含量古罗糖醛酸的藻酸盐或酰胺化的果胶涂层可提供最佳结果。这可能是因为这两者都具有在凝胶涂层内形成非常稳定的交联的巨大潜力。

BACKGROUND & AIMS: :It is well-recognised that steady-state isometric muscle force is decreased following active shortening (force depression, FD) and increased following active stretch (force enhancement, FE). It has also been demonstrated that passive muscle force is increased following active stretch (passive FE). Several studies have reported that FD increases with shortening amplitude and that FE and passive FE increase with stretch amplitude. Here, we investigate whether these trends continue with further increases in shortening or stretch amplitude. Experiments were performed using in situ cat soleus muscles (n=8 for FD; n=7 for FE and passive FE). FD, FE and passive FE were measured after shortening or stretch contractions that covered as wide a range of amplitudes as practically possible without damaging the muscles. FD increased approximately linearly with shortening amplitude, over the full range of amplitudes investigated. This is consistent with the hypothesis that FD arises from a stress-induced inhibition of crossbridges. FE increased with stretch amplitude only up to a point, and then levelled off. Passive FE, and the transient increase in force at the end of stretch, showed relationships to stretch amplitude that were qualitatively very similar to the relationship for FE, increasing only until the same critical stretch amplitude had been reached. We conclude that FE and passive FE do not increase with stretch amplitude under all circumstances. This finding has important consequences for determining the mechanisms underlying FE and passive FE because any mechanism that is proposed to explain them must be able to predict it.

背景与目标： : 众所周知，主动缩短 (力降低，FD) 后，稳态等距肌肉力降低，主动拉伸 (力增强，FE) 后，稳态等距肌肉力增加。还已证明，主动拉伸 (被动FE) 后，被动肌肉力量会增加。一些研究报告说，FD随缩短幅度而增加，FE和被动FE随拉伸幅度而增加。在这里，我们研究这些趋势是否随着缩短或拉伸幅度的进一步增加而继续。使用原位猫比目鱼肌进行实验 (FD为n = 8; FE和被动FE为n = 7)。在缩短或拉伸收缩后测量FD，FE和被动FE，这些收缩实际上覆盖了尽可能宽的振幅范围，而不会损坏肌肉。在所研究的整个振幅范围内，FD随振幅的缩短而近似线性增加。这与FD由应力诱导的交叉桥抑制引起的假设是一致的。FE仅随拉伸幅度增加到一个点，然后趋于平稳。被动FE和拉伸结束时的瞬时力增加显示出与拉伸幅度的关系，在质量上与FE的关系非常相似，仅在达到相同的临界拉伸幅度之前才增加。我们得出的结论是，在所有情况下，FE和被动FE都不会随拉伸幅度而增加。这一发现对于确定FE和被动FE的潜在机制具有重要的影响，因为提出的任何解释它们的机制都必须能够预测它。

BACKGROUND & AIMS: :The purpose of this study was to test the hypothesis that runners having different running economies show differences in the mechanical and morphological properties of their muscle-tendon units (MTU) in the lower extremities. Twenty eight long-distance runners (body mass: 76.8+/-6.7 kg, height: 182+/-6 cm, age: 28.1+/-4.5 years) participated in the study. The subjects ran on a treadmill at three velocities (3.0, 3.5 and 4.0 m s(-1)) for 15 min each. The V(O(2)) consumption was measured by spirometry. At all three examined velocities the kinematics of the left leg were captured whilst running on the treadmill using a high-speed digital video camera operating at 250 Hz. Furthermore the runners performed isometric maximal voluntary plantarflexion and knee extension contractions at eleven different MTU lengths with their left leg on a dynamometer. The distal aponeuroses of the gastrocnemius medialis (GM) and vastus lateralis (VL) were visualised by ultrasound during plantarflexion and knee extension, respectively. The morphological properties of the GM and VL (fascicle length, angle of pennation, and thickness) were determined at three different lengths for each MTU. A cluster analysis was used to classify the subjects into three groups according to their V(O(2)) consumption at all three velocities (high running economy, N=10; moderate running economy, N=12; low running economy, N=6). Neither the kinematic parameters nor the morphological properties of the GM and VL showed significant differences between groups. The most economical runners showed a higher contractile strength and a higher normalised tendon stiffness (relationship between tendon force and tendon strain) in the triceps surae MTU and a higher compliance of the quadriceps tendon and aponeurosis at low level tendon forces. It is suggested that at low level forces the more compliant quadriceps tendon and aponeurosis will increase the force potential of the muscle while running and therefore the volume of active muscle at a given force generation will decrease.

背景与目标： : 这项研究的目的是检验以下假设: 具有不同跑步经济性的跑步者在下肢的肌肉肌腱单位 (MTU) 的机械和形态特性上存在差异。28名长跑运动员 (体重: 76.8 +/-6.7千克，身高: 182 +/-6厘米，年龄: 28.1 +/-4.5岁) 参加了这项研究。受试者在跑步机上以三种速度 (3.0、3.5和4.0 m s(-1)) 分别运行15分钟。通过肺活量测定法测量V(O(2)) 的消耗量。在所有三个检查的速度下，使用以250Hz运行的高速数字摄像机在跑步机上跑步时捕获左腿的运动学。此外，跑步者在测力计上的左腿以11种不同的MTU长度进行了等距最大的自愿plant屈和膝盖伸展收缩。在plant屈和膝关节伸展过程中，分别通过超声观察腓肠肌内侧 (GM) 和股外侧 (VL) 的远端腱膜。对于每个MTU，以三种不同的长度确定GM和VL的形态特性 (分束长度，顶角和厚度)。使用聚类分析根据受试者在所有三个速度下的V(O(2)) 消耗将受试者分为三组 (高运行经济，N = 10; 中等运行经济，N = 12; 低运行经济，N = 6)。GM和VL的运动学参数和形态特性均未在组之间显示出显着差异。最经济的跑步者在肱三头肌MTU中显示出更高的收缩强度和更高的归一化肌腱刚度 (肌腱力和肌腱应变之间的关系)，而在低水平的肌腱力下，股四头肌腱和腱膜的顺应性更高。建议在低水平的力下，更顺应性的股四头肌腱和腱膜会增加跑步时肌肉的力势，因此在给定的力产生下活动肌肉的体积会减少。

BACKGROUND & AIMS: In the initial stages of crystallization of proteins, monomers aggregate rapidly and form nuclei and large fractal clusters, as previously shown by dynamic light scattering experiments (Georgalis, Y., J. Schüler, J. Frank, D. M. Soumpasis, and W. Saenger. 1995. Protein crystallization screening through scattering techniques. Adv. Colloid Interface Sci. 5857-86). In this communication we initiate an effort to understand the effective interactions controlling charged protein aggregation and crystallization using the potential of mean force (PMF) theory. We compute the PMFs of the system lysozyme-water-NaCl within the framework of the hypernetted chain approximation for a wide range of protein and salt concentrations. We show that the computed effective interactions can rationalize the experimentally observed aggregation behavior of lysozyme under crystallization conditions.

背景与目标： 在蛋白质结晶的初始阶段，单体迅速聚集并形成核和大的分形簇，如先前的动态光散射实验所示 (Georgalis，Y.，J. Sch ü ler，J. Frank，d.m.Sompasis，和W. Saenger。1995。通过散射技术进行蛋白质结晶筛选。胶体界面科学。5857-86)。在此交流中，我们开始努力使用平均力 (PMF) 理论来了解控制带电蛋白质聚集和结晶的有效相互作用。我们在各种蛋白质和盐浓度的超净链近似框架内计算系统溶菌酶-水-NaCl的pmf。我们证明，计算出的有效相互作用可以使结晶条件下实验观察到的溶菌酶的聚集行为合理化。

BACKGROUND & AIMS: OBJECTIVE:To review the findings and discuss the implications of mechanical ventilator weaning protocols in children. DESIGN:A critical appraisal of Randolph et al. Effect of mechanical ventilator weaning protocols on respiratory outcomes in infants and children: A randomized controlled trial. JAMA 2002;288:2561-2568, and literature review. FINDINGS:There was no difference in ventilator weaning times between children randomized to a ventilator weaning protocol (pressure support, volume support, or no protocol). However, the study did show that increased sedative use during the first 24 hrs of weaning (the only time during which these data were collected) was an important predictor of weaning duration (p < .001) and weaning failure (p = .04). CONCLUSIONS:The majority of children are weaned from mechanical ventilation over a short period of time. Weaning protocols may not shorten this brief duration of weaning but may have other advantages such as improved collaboration between healthcare team members. Future research into the effects of sedation on weaning from mechanical ventilation is needed in children.

背景与目标：

BACKGROUND & AIMS: :In the present account it is proposed that in smokers the transition from peripheral airway disease to COPD is characterized by three sequential stages: Stage I, during which the closing volume eventually exceeds the functional residual capacity; Stage II, during which tidal expiratory flow limitation (EFL) is eventually exhibited; and Stage III, during which dynamic hyperinflation progressively increases leading to dyspnea and exercise limitation, which may be considered as markers of overt disease. Presence of airway closure (Stage I) and EFL (Stage II) in the tidal volume range may promote peripheral airway injury and accelerate the abnormalities of lung function. It is such injury that may determine which smoker is destined to develop COPD.

背景与目标： : 在本报告中，建议吸烟者从外周气道疾病到COPD的转变以三个连续阶段为特征: 阶段I，在此期间闭合量最终超过功能剩余容量; 阶段II，在此期间最终表现出呼气流量限制 (EFL); 第三阶段，在此期间，动态过度通货膨胀逐渐增加，导致呼吸困难和运动受限，这可能被认为是明显疾病的标志。潮气量范围内存在气道关闭 (I期) 和EFL (II期) 可能会促进周围气道损伤并加速肺功能异常。正是这种伤害可能决定了哪个吸烟者注定会发展为COPD。

BACKGROUND & AIMS: :To study the force-velocity characteristics of human knee-hip extension movement, a dynamometer, in which force was controlled by a servo system, was developed. Seated subjects pressed either bilaterally or unilaterally a force plate, a horizontal position of which was servo-controlled so as to equalize the measured force and a force command generated by a computer at a time resolution of 2 ms (force clamp). The force command was based on the relation between maximum isometric force and foot position within the range between 70% and 90% of "leg length" (LL: longitudinal distance between the sole of the foot and the hip joint), so that the same force relative to the maximum isometric force was consistently applied regardless of the foot position. By regulating the force according to this function, the force-velocity relation was determined. The force-velocity relation obtained was described by a linear function (n=17, r=-0.986 for 80% LL, r=-0.968 for 85% LL) within a range of force between 0.1 and 0.8F(0) (maximum isometric force). The maximum force extrapolated from the linear regression (F(max)) coincided with F(0) (n=17, F(0)/F(max)=1.00+/-0.09 for 80% LL and 1.00+/-0.20 for 85% LL). Also, the velocity at zero force (V(max)) was obtained from the extrapolation. When compared to the bilateral movements, unilateral movements gave rise to a smaller F(max) but the same V(max), suggesting that V(max) is independent of force and therefore represents the proper unloaded velocity. It is suggested that some neural mechanisms may be involved in the force-velocity relation of the knee-hip extension movement, and make it exhibit a linear appearance rather than a hyperbola.

背景与目标： : 为了研究人体膝关节-髋关节伸展运动的力-速度特性，开发了一种测力计，该测力计由伺服系统控制。就座的对象在两侧或一侧按压一个测力板，其水平位置受到伺服控制，以使测得的力和计算机以2 ms的时间分辨率 (力夹) 产生的力命令相等。力命令基于最大等距力和足部位置之间的关系，范围在 “腿长” 的70% 和90% 之间 (LL: 脚底和髋关节之间的纵向距离)，因此，无论脚的位置如何，都始终施加相对于最大等距力的相同力。通过根据此函数调节力，确定了力-速度关系。在0.1和0.8F(0) (最大等距力) 之间的力范围内，通过线性函数 (n = 17，对于80% LL，r =-0.986，对于85% LL，r =-0.968) 描述获得的力-速度关系。从线性回归外推的最大力 (F(max)) 与F(0) 一致 (对于80% LL，n = 17，F(0)/F(max)= 1.00 +/-0.09，对于85% LL，1.00 +/-0.20)。此外，通过外推获得了零力 (V(max)) 的速度。与双边运动相比，单边运动产生的F(max) 较小，但V(max) 相同，这表明V(max) 与力无关，因此代表适当的空载速度。建议某些神经机制可能参与膝髋伸展运动的力-速度关系，并使其表现出线性外观而不是双曲线。

BACKGROUND & AIMS: :This report is a study of structure, castability, mechanical properties as well as corrosion behaviour of titanium doped with up to 5 weight percentage (wt%) of a series of alloy elements, including Ta, Mo, Nb, Hf, Zr, Sn, Bi and Ag. The results indicate that, with addition of 1 wt% alloy element, Bi and Mo were most effective in enhancing the castability of titanium. With more alloy elements added, the castability values of most alloys more or less decreased. Except Ti-Mo system, all Ti alloys with a fine acicular morphology had the same crystal structure (hcp) as that of c.p. Ti with a typical lath type morphology. When 3 wt% or more Mo was added, a finer orthorhombic alpha'' phase was formed. The microhardness and bending strength values of Ti alloys were all higher than those of c.p. Ti. Among all alloys, Ti-Mo system exhibited the highest hardness and strength level. For a certain alloy, the bending strength did not necessarily increase with its alloy content. Except Ti-5Zr and Ti-Mo alloys, the bending moduli of most alloy systems were not much different from that of c.p. Ti. All alloys showed an excellent resistance to corrosion in Hanks' solution at 37 degrees C.

背景与目标： : 本报告研究了掺有高达5重量百分比 (wt %) 的一系列合金元素 (包括Ta，Mo，Nb，Hf，Zr，Sn，Bi和Ag) 的钛的结构，可铸造性，机械性能以及腐蚀行为。结果表明，添加1 wt % 合金元素时，Bi和Mo最有效地提高了钛的可铸造性。随着添加更多的合金元素，大多数合金的可铸造性值或多或少会降低。除Ti-Mo体系外，所有具有细针状形态的Ti合金均具有与c.p.相同的晶体结构 (hcp)。具有典型板条型形态的Ti。当添加3 wt % 或更多Mo时，形成了更细的正交晶型 α'' 相。Ti合金的显微硬度和弯曲强度值均高于c.p.Ti。在所有合金中，Ti-Mo体系表现出最高的硬度和强度水平。对于某种合金，弯曲强度不一定随其合金含量而增加。除Ti-5Zr和Ti-Mo合金外，大多数合金体系的弯曲模量与c.p.没有太大差异。Ti。所有合金在汉克斯溶液中在37 ℃ 下均表现出优异的耐腐蚀性。

BACKGROUND & AIMS: :In this study, the distribution, transfer and fate of both polychlorinated biphenyls (PCBs) and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes. Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms. Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation. Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns, and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater. According to these findings, a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed. In the practice of mechanical collections of bloom biomass from Lake Taihu, cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory.

背景与目标： : 在这项研究中，系统地研究了两个中国湖泊中通过浮游植物路线的多氯联苯 (pcb) 和氰基毒素的分布，转移和命运。结果表明，PCB的吸附/生物蓄积动力学与绿藻和硅藻的生物量呈显着正相关。浮游植物的总脂质含量是影响PCB吸附/生物积累的主要因素。由于水柱中细胞密度高，脂质含量相对较低的蓝藻水华也可以吸收大量的多氯联苯，这一过程被认为是中国富营养化淡水中多氯联苯转移的主要途径。根据这些发现，提出并证实了通过浮游植物获得多氯联苯命运的新途径和绿色生物吸附概念。在机械收集太湖盛开生物质的实践中，发现根据该理论同时非常有效地去除了氰基毒素/蓝细菌和多氯联苯。

BACKGROUND & AIMS: OBJECTIVES:The purposes of this study included the following: (1) to predict L3 contact force during side-lying lumbar manipulation by combining direct and indirect measurements into a single mathematical framework and (2) to assess the accuracy and confidence of predicting L3 contact force using common least squares (CLS) and weighted least squares (WLS) methods. METHODS:Five participants with no history of lumbar pain underwent 10 high-velocity, low-amplitude lumbar spinal manipulations at L3 in a side-lying position. Data from 5 low-force criterion standard trials where the L3 contact force was directly measured were used to generate participant-specific force prediction algorithms. These algorithms were used to predict L3 contact force in 5 experimental trials performed at therapeutic levels. The accuracy and effectiveness of CLS and WLS methods were compared. RESULTS:Differences between the CLS-predicted forces and the criterion standard-measured forces were 621.0 ± 193.5 N. Differences between the WLS-predicted forces and the criterion standard-measured forces were -3.6 ± 9.1 N. The 95% limits of agreement ranged from 234.0 to 1008.0 N for the CLS and -21.9 to 14.7 N for the WLS. During both the criterion standard and experimental trials, the CLS overestimated contact forces with larger variance than the WLS. CONCLUSION:This novel method to predict spinal contact force combines direct and indirect measurements into a single framework and preserves clinically relevant practitioner-participant contacts. As advanced instrumentation becomes available, this framework will enable advancements in training and high-quality research on mechanisms of spinal manipulative therapy.

背景与目标：

BACKGROUND & AIMS: :A three-dimensional static model is described to evaluate the forces on low-back muscles and on the spine during manual handling tasks and other forceful activities. It is simple to use either with a calculator or programmed onto a micro-computer, whilst being more accurate than existing simple models. Comparisons are made with a more sophisticated model that requires mathematical libraries and programming skills. As predictions are similar, so is the area of validity: the proposed model's accuracy is good for light tasks but poorer for strenuous ones.

背景与目标： : 描述了一个三维静态模型，以评估在手动处理任务和其他有力活动期间对下背部肌肉和脊柱的作用力。它可以简单地与计算器一起使用或编程到微型计算机上，同时比现有的简单模型更准确。使用需要数学库和编程技能的更复杂的模型进行比较。由于预测是相似的，因此有效性领域也是相似的: 所提出的模型的准确性对于轻型任务是好的，而对于繁重的任务则较差。

BACKGROUND & AIMS: :Healing of the rat Achilles tendon is sensitive to mechanical loading, and the callus strength is reduced by 3/4 after 14 days, if loading is prevented. Exogenous GDFs stimulate tendon healing. This response is influenced by loading: without loading, cartilage and bone formation is initiated. This implies BMP signaling is crucial during tendon healing and influenced by mechanical loading. We therefore asked if mechanical loading influences the gene expression of the BMP signaling system in intact and healing tendons, and how the BMP signaling system changes during healing. The genes were four BMPs (OP-1/BMP-7, GDF-5/CDMP-1/BMP-14, GDF-6/CDMP-2/BMP-13, and GDF-7/CDMP-3/BMP-12), two receptors (BMPR1b and BMPR2), and the antagonists follistatin and noggin. The Achilles tendon was transected in rats and left to heal. Half of the rats had one Achilles tendon unloaded by injection of Botox in the calf muscles. Ten tendons were analyzed before transection and for each of four time points. All genes except noggin were expressed at all time points, but followed different patterns during healing. Loading strongly decreased the expression of follistatin, which could lead to increased signaling. The BMP system appears involved in tendon maintenance and healing, and may respond to mechanical loading.

背景与目标： : 大鼠跟腱的愈合对机械负荷敏感，如果防止负荷，则在14天后愈伤组织强度降低3/4。外源性GDFs刺激肌腱愈合。这种反应受负荷影响: 在没有负荷的情况下，开始软骨和骨形成。这意味着BMP信号在肌腱愈合过程中至关重要，并受到机械负荷的影响。因此，我们询问机械负荷是否会影响完整和愈合肌腱中BMP信号系统的基因表达，以及BMP信号系统在愈合过程中如何变化。基因是四个bmp (OP-1/BMP-7，GDF-5/CDMP-1/BMP-14，GDF-6/CDMP-2/BMP-13和GDF-7/CDMP-3/BMP-12)，两个受体 (BMPR1b和BMPR2) 以及拮抗剂follistatin和noggin。在大鼠中横切跟腱并使其愈合。通过在小腿肌肉中注射肉毒杆菌毒素，一半的大鼠的跟腱被卸载。在横切之前和四个时间点中的每一个都分析了十根肌腱。除noggin外，所有基因均在所有时间点表达，但在愈合过程中遵循不同的模式。负载强烈降低了卵泡抑素的表达，这可能导致信号传导增加。BMP系统似乎参与肌腱的维护和愈合，并且可能对机械负荷做出反应。