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1.
Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using a joint coordinate system approach. Test variables were defined for eversion and tibial rotation. The results showed that the differences in bone movements between barefoot and shod running were small and unsystematic (mean effects being less than 2 degrees ) compared with the differences between the subjects (up to 10 degrees ). However, differences may occur during midstance when extreme shoe modifications (i.e. posterior orthosis) are used. It is concluded that calcaneal and tibial movement patterns do not differ substantially between barefoot and shod running, and that the effects of these interventions are subject specific. The result of this in vivo study contrasts with previous investigations using skin and shoe mounted markers and suggests that these discrepancies may be the result of the overestimation with externally mounted markers.  相似文献   

2.
3.
In vivo tracking of the human patella.   总被引:3,自引:0,他引:3  
The purpose of this study was to describe the dynamic, in vivo, three-dimensional tracking pattern of the patella for one normal male subject. Intracortical pins were inserted into the patella, tibia, and femur. The subject performed seated and squatting knee flexion/extension, and maximum voluntary quadriceps contractions. In addition, the vastus medialis oblique was subjected to maximal electrical stimulation. Motions of the markers attached to the intracortical pins were analyzed using an automated video system. Patellar and tibial motions were determined relative to a femoral reference system. While the tibia flexed 50 degrees from full extension (seated condition), the patella flexed 30.3 degrees, tilted laterally 10.3 degrees, and shifted laterally 8.6 mm. In general, these results show qualitative agreement with the data collected from cadaveric specimens [van Kampen and Huiskes, J. orthop. Res. 8, 372-382 (1990)]. The differences present may reflect different passive constraints to patellar motions, and different relative loading of the individual quadriceps components, in our study compared to the cadaveric study. Only small differences were found between patellar motions in the seated and squatting conditions. Differences in patellar displacements produced by (1) maximal electrical stimulation of the vastus medialis oblique, and (2) maximum voluntary quadriceps contraction, at 30 degrees knee flexion and full extension, may reflect the dominant influence of passive constraints, and the vastus lateralis, on normal patellar motions. Further in vivo study of patellar tracking seems warranted to evaluate surgical and conservative interventions for patellofemoral disorders.  相似文献   

4.
Two devices for indoor processing of insect collections are described. The first device markedly simplifies comparative studies of large series of insects. The second device allows the height of labels on pins to be adjusted so that a set of labels can be mounted simultaneously, which is important when a large amount of material is processed.  相似文献   

5.
1. Drag coefficients ( C D) of bryophyte-covered rocks were measured to see whether these differed between species. Replicate rocks, each supporting one of six bryophyte taxa, were attached to a base plate mounted on Teflon bearings in a flow tank. The drag force exerted on rocks with and without bryophyte material was measured by a strain gauge at different water velocities.
2. The difference in C D between rocks with and without bryophyte material was calculated for each plant, and expressed as a percentage change ( δC D). This varied significantly from 0 in three of the six taxa. The cushion-shaped moss Bryum blandum increased the C D by around 10%. The moss Blindia lewinskyae and liverwort Cryptochila grandiflora decreased the C D by around 40 and 30%, respectively, presumably reflecting their streamlined growth.
3. Drag characteristics of aquatic bryophytes may help explain differences in their resistance to fast flows. Furthermore, we suggest that some aquatic bryophytes can increase substrate stability by streamlining rocks, rendering them less prone to movement.  相似文献   

6.
A 2-year study of three natural populations of the distylousJasminum fruticans showed that mean fruit and seed production were significantly greater in shortstyled plants (thrums) than in long-styled plants (pins). In this study, we investigated the role of four sequential factors which may differentially influence fruit and seed set in the two floral morphs: (1) differences in flowering phenology, (2) a limitation of pollen transfer towards pins, (3) a differential capacity of the two morphs to act through famale and male function and (4) differential fruit abortion in the two morphs. Fruit set was significantly influenced by differences in flowering phenology although there were no differences in flowering time between the two morphs. supplementary pollinations in a natural population significantly increased fruit set and reduced the difference in fruit set between the two morphs in relation to controls, indicating a limitation on pollen transfer which was most severe towards pin stigmas. In reciprocal crosses, seed set was significantly dependent on the paternal and maternal identity of the pin parent. There was no significant variation among thrums for their performance as male or female parent. Furthermore, individual pin plants with relatively high percentage seed set as female parents gave poor seed set as male parents and vice-versa. Whereas fruit removal had no effect on seed number in thrum plants, a greater proportion of viable seeds were produced on pin plants which were left to naturally mature their fruits than on pins which had fruits artificially removed, suggesting the occurrence of selective fruit abortion in pins but not in thrums. The initially greater maternal fitness of thrums due to their greater success as pollen recipients may thus be opposed by increased viable seed set in the pins due to factors acting after the pollination stage. The relative reproductive success of floral morphs in the distylousJ. fruticans is thus differentially influenced by ecological factors occurring at different stages of the reproductive process.  相似文献   

7.
愉悦蓼具有典型的二型花柱现象。通过统计安徽部分地区愉悦蓼长、短柱花花型数量、柱头和花药高度差及结实率;观察愉悦蓼的长、短柱花的型比;结合苯胺蓝染色鉴定愉悦蓼长、短柱花的花粉与柱头的亲和性。结果表明,愉悦蓼长、短柱花的型比符合1∶1;长柱花的结实率较大;自花授粉组合中的花粉在柱头上也能萌发出花粉管,但不能到达子房。  相似文献   

8.
The effects of tagging on small cetaceans are difficult to assess due to logistical difficulties in recapturing the whales. In this study two narwhals, Monodon monoceros, and five harbor porpoises, Phocoena phocoena, were recaptured between 297 and 767 days after instrumentation with satellite transmitters. The transmitters were mounted by pins that were pushed through the fins of the porpoises or the backs of the narwhals. Overall body condition seemed unaffected by the instrumentations. Macroscopical examination revealed that umbilicalization of the tissue surrounding the pins was almost complete. On one of the narwhals the reepithelialization created a closed tunnel where the pins were isolated from the subdermal tissue, however the reepithelialization was incomplete around the middle of the pin and a low‐grade inflammation increased with decreasing thickness of epidermis. The inflammation consisted of mononuclear cells, mainly lymphocytes. With increasing inflammation the number of neutrophils and macrophages increased. In the lymphoid follicular hyperplasia macrophages and a few neutrophils were found, in one case accompanied by Splendore‐Hoeppli material with radiating eosinophilic clubs and Gram‐positive cocci. Immunohistochemical staining of the cocci for Staphylococcus aureus was positive. The observations from the recaptured cetaceans suggest that the instrumentations caused only temporary and low‐grade inflammatory responses.  相似文献   

9.
A procedure for creating and imaging capillary bridges in slit-pore geometry is presented. High aspect ratio hydrophobic pillars are fabricated and functionalized to render their top surfaces hydrophilic. The combination of a physical feature (the pillar) with a chemical boundary (the hydrophilic film on the top of the pillar) provides both a physical and chemical heterogeneity that pins the triple contact line, a necessary feature to create stable long but narrow capillary bridges. The substrates with the pillars are attached to glass slides and secured into custom holders. The holders are then mounted onto four axis microstages and positioned such that the pillars are parallel and facing each other. The capillary bridges are formed by introducing a fluid in the gap between the two substrates once the separation between the facing pillars has been reduced to a few hundred micrometers. The custom microstage is then employed to vary the height of the capillary bridge. A CCD camera is positioned to image either the length or the width of the capillary bridge to characterize the morphology of the fluid interface. Pillars with widths down to 250 µm and lengths up to 70 mm were fabricated with this method, leading to capillary bridges with aspect ratios (length/width) of over 1001.  相似文献   

10.
The effect of light quality on protocorm-like bodies (PLBs) of Dendrobium officinale was investigated. PLBs of D. officinale were incubated under a number of different light conditions in vitro, namely: dark conditions; fluorescent white light (Fw); red light-emitting diodes (LEDs); blue LEDs; half red plus half blue [RB (1:1)] LEDs; 67% red plus 33% blue [RB (2:1)] LEDs; and 33% red plus 67% blue [RB (1:2)] LEDs. Growth parameters, number of shoots produced per PLB, chlorophyll concentration and carotenoid concentration were measured after 90 days culture. The percentage of PLBs producing shoots was 85% under blue LEDs. In contrast, the percentage of PLBs producing shoots was less than 60% under dark conditions, fluorescent white light and red LEDs. The number of shoots produced per PLB was more than 1.5 times greater under blue LEDs, RB (1:1) LEDs and RB (1:2) LEDs than those cultured under other light treatments [dark, Fw, red LEDs and RB (2:1)]. Chlorophyll and carotenoid concentrations were significantly higher under blue LEDs and different red plus blue LED ratios, compared to other light treatments (dark, Fw and red LEDs). Blue LEDs, Fw, and RB (1:2) LEDs produced higher dry matter accumulations of PLBs and shoots. This study suggests that blue LEDs or RB (1:2) LEDs could significantly promote the production of shoots by protocorm-like bodies of D. officinale and increase the dry matter of PLBs and the accumulation of shoot dry matter in vitro.  相似文献   

11.
绿黄色光二极管(LED)附加在塑胶杯和胶片捕捉器可增加捕捉实验室和温室中昆虫的数量。附加有530nm绿黄色LED的塑胶杯捕捉器比没有附加的捕捉到更多的Trialeurodes vaporariorum(Westwood)和Bemisia tabaci(Gennadius)B生态型。在温室中昆虫笼以四季豆和棉花试验,附加有530nm绿黄色LED的黄色胶片(YC)和透明塑胶片(CS)分别缩写为LED—YC和LED—CS)比每一种没有附加的捕捉器捕捉到更多的T.vaporariorum,B.tabaci B生态型,Ahis gossypii(Glover)和Bradysia coprophila(Lintner)成虫。绿黄色LED—YC在温室中有用为监测和控制的潜在性。  相似文献   

12.
Abstract  Light-emitting diodes (LEDs) were attached to plastic cup and sticky card traps to improve pest insect catches in the laboratory and in greenhouses. Plastic cup traps equipped with 530 nm lime green LEDs caught more adult Trialeurodes vaporariorum (Westwood) and Bemisia tabaci (Gennadius) biotype B compared with plastic cup traps alone. Yellow sticky card (YC) and clear plastic sticky card (CS) traps equipped with lime green LEDs (LED-YC and LED-CS, respectively) caught more adult T. vaporariorum, B. tabaci biotype B, Aphis gossypii (Glover) and Bradysia coprophila (Lintner) compared with unlit traps of each type in greenhouse cage studies with shell beans, Phaseolus vulgaris (L.) and cotton, Gossypium hirsutum (L.). The lime green LED equipped YC traps have potential for use in greenhouses for insect detection, monitoring, and control.  相似文献   

13.
An axial extensometer able to measure global bone strain magnitudes and rates encountered during physiological activity, and suitable for use in vivo in human subjects, is described. The extensometer uses paired capacitive sensors mounted to intraosseus pins and allows measurement of strain due to bending in the plane of the extensometer as well as uniaxial compression or tension. Data are presented for validation of the device against a surface-mounted strain gage in an acrylic specimen under dynamic four-point bending, with square wave and sinusoidal loading inputs up to 1500 mu epsilon and 20 Hz, representative of physiological strain magnitudes and frequencies. Pearson's correlation coefficient (r) between extensometer and strain gage ranged from 0.960 to 0.999. Mean differences between extensometer and strain gage ranged up to 15.3 mu epsilon. Errors in the extensometer output were directly proportional to the degree of bending that occurs in the specimen, however, these errors were predictable and less than 1 mu epsilon for the loading regime studied. The device is capable of tracking strain rates in excess of 90,000 mu epsilon/s.  相似文献   

14.
The purpose of this study was to investigate the role of muscle activation on the relative motion between tibia and femur. Impacts were initiated under the heels of four volunteers in three different activation levels of muscles crossing the extended knee joint: 0%, 30% and 60% of previously performed maximal voluntary isometric contractions. Impact forces were measured and tibial and femoral accelerations and displacements were determined by means of accelerometry. The accelerometers were mounted on the protruding ends of intracortical pins, inserted into the distal aspect of the femur and proximal aspect of the tibia. Under the 0%-condition the impact force (475±64N) led to 2.3±1.2mm knee compression and to 2.4±1.9mm medio-lateral and 4.4±1.1mm antero-posterior shear. The impact forces increased significantly with higher activation levels (619±33N (30%), 643±147N (60%)), while the knee compression (1.5±1.2, 1.4±1.3mm) and both medio-lateral shear (1.8±1.4, 1.5±1.1mm) and antero-posterior shear (2.6±1.3, 1.5±1.1mm) were significantly reduced. This study indicated that muscles are effective in controlling the relative motion between tibia and femur when the knee is subjected to external forces.  相似文献   

15.
The effects of externally mounted ultrasonic tags on the tail beat frequency (TBF) and opercular beat rate (OBR) of rainbow trout was measured at different swimming speeds. The increase in relative drag caused by the tags was also measured. Two tag types were used: one where both the circuitry and the battery were in a single package mounted on one side of the fish, the other where they were in two packages mounted symmetrically on either side of the fish. Both tag types raised both TBF and OBR. Of the two, the symmetrical tag effects behaviour less, especially at low swimming speeds, even though it causes a greater increase in relative drag.  相似文献   

16.
V. Delucchi 《BioControl》1961,6(2):109-113
Summary The author proposes to standardize the preparation technique for microhymenoptera. The insects have to be presented for identification in a dry state, mounted on a minute pin or glued on a heavy paper point (double-mounting). Preference is given to the mounting on minute pin, as this method has the advantage that a specimen pinned with a minuten may be removed from its support and each morphological detail easily observed. The minuten is fixed to a short strip of soft material such as polyporus (bracket fungus); if this is not available, stiff paper may be used. The support with the pinned specimen is then attached to a pin no. 3 (fig. 1–3). The absence of glue is advantageous, especially in subtropical countries, where the glue is generally destroyed by bacteria and fungi. When the pins are unavailable for this double-mounting technique, the author proposes to glue the thoracic pleurae of the insect to the previously folded tip of a heavy paper point (fig. 6). The material for identification may be preserved in a liquid medium (as alcohol with some drops of glycerine) after a series of individuals have been prepared according to the double-mounting technique. Also, specimens in excess may be sent dry in a plastic or glass tube between two cellucotton masses.   相似文献   

17.
Abstract

Four types of light emitting diodes (LEDs) were used in three combinations (all blue [BBB], red: blue: far-red [RBFr]=4:1:1 and red: green: blue [RGB]=4:1:1) and seven irradiation cycles (12 h/12 h photoperiod, 1 Hz, 10 Hz, 100 Hz, 1 KHz, 10 KHz and 100 KHz) were applied to examine their effect on growth, stem color and phenolic compounds (homoorientin, orientin, rutin, vitexin and isovitexin) in buckwheat (Fagopyrum esculentum cv. Great Ruby) sprouts. With a few exceptions, among all the combinations and irradiation cycles of LEDs, the Great Ruby cultivar showed significant differences in total height and dry weight of sprouts. The study revealed that there was a direct effect of different combination and irradiation cycles of LEDs on sprout height and dry weight; and among the combinations, RBFr and BBB had more positive effect than RGB. Increasing irradiation cycles markedly decreased the red color of stalks of F. esculentum cv. Great Ruby sprouts, with no significant effect on leaf color. In sprouts, the rutin content of leaves and stalks was higher at 12 h photoperiod and the amount in leaves was 5–7% higher than that of stalks in all combinations and irradiation cycles of LEDs. Among polyphenols, the rutin content in stalks was 1.45–2.97 mg g?1 dry weight and the maximum amount of rutin was obtained from RGB combination of LEDs. In leaves, higher amounts of homoorientin, orientin and vitexin+isovitexin were obtained from the RGB combination and there were significant differences between RGB and other two combinations of LEDs. On the other hand, in between the irradiation cycles used in the study, there were no significant differences for other polyphenols in leaves and stalks of buckwheat sprouts.  相似文献   

18.
NPK‐10:26:26 complex fertilizer based culture medium was studied for the mass production of Spirulina platensis using different light emitting diodes (LEDs). First, cultivation was carried out under white LED to formulate the optimum fertilizer loading for which Spirulina growth was maximized. Optimum composition for newly formulated fertilizer medium was NPK fertilizer ?0.76 g L?1 and sodium bicarbonate ?10.0 g L?1 and corresponding biomass productivity was found to be 76.67 mg L?1 day?1. The effect of different LEDs (for example, blue, white, red, green and yellow) on Spirulina growth kinetics and the accumulation of chlorophyll, protein and lipid content was determined using the optimum NPK fertilizer medium. Kinetic parameters (i.e., biomass productivity, maximum specific growth rate, maximum biomass concentration, nitrogen‐to‐biomass conversion factor and phosphorus‐to‐biomass conversion factor) and chlorophyll accumulation were affected by the use of different LEDs and follow the following trend: blue > white > red > green > yellow, whereas protein and lipid accumulation was almost independent of LEDs used. Elemental C, N, P and K concentrations were measured to find the effects of nutrients for the growth of Spirulina platensis. Physicochemical parameters (pH and conductivity) were also monitored during biomass growth under different LEDs. Finally, biomass growth using NPK‐10:26:26 fertilizer under different LEDs was compared with standard Zarrouk medium and better growth results were obtained using optimally formulated NPK‐10:26:26 fertilizer medium.  相似文献   

19.
We studied the development of 26 flower traits under natural conditions in three clades of the genus Amsinckia (Boraginaceae). Each clade contained both a derived highly self-fertilizing taxon and an ancestral more highly outcrossing taxon. The more outcrossing taxa contained two flower morphs—pins and thrums—with opposite positioning of the sex organs (heterostyly). The highly selfing taxa had smaller flowers with sex organs in close proximity (homostyly). Growth trajectories were quantified over the entire or nearly the entire period from primordium initiation to flower opening. These trajectories were compared in the heterochronic framework and, in contrast with previous studies, character size was tracked over time rather than relative to another character. We focused on three hypotheses: (1) The distinct developmental trajectories leading to pins and thrums should be similar in all clades, while the trajectories leading to homostylous flowers might differ among clades. This was supported. Specifically, contrasting growth rates of stamen and pistil heights in heterostylous flowers caused pin and thrum flowers to have the reciprocal arrangement of anther and stigma heights. From the viewpoint of heterochrony, the decreased size (paedomorphosis) of the homostylous morph, compared to pins and thrums, resulted from decreased growth rate (neoteny) and earlier offset (progenesis) in all clades. Nevertheless, multiple heterochronic processes were involved in the mosaic development and evolution of homostylous flowers. (2) We tested the hypothesis that small, self-fertilizing flowers have reduced development times, one of the proposed selective advantages of increased self-fertilization rates. We found in contrast that developmental duration of homostylous flowers was either the same (two clades) or longer (one clade) compared to duration of pins and thrums. (3) Finally, we tested von Baer’s Law, which proposes that developmental differences among closely related taxa should arise later in development than differences among more distantly related taxa. Von Baer’s Law was supported strongly among homostyles, moderately among thrums and weakly among pins.  相似文献   

20.
IntroductionNumerous measurement devices can help clinicians during the knee examination. However, manual evaluation still remains routinely used to assess the knee laxities. The present study evaluated how accurate was a clinician for a varus-valgus stress test. We compared the clinician evaluation to the objective measurement of the knee movements during the same test session.MethodsWe studied six fresh-frozen anatomical lower limbs. The clinician performed a varus-valgus stress test in extension and at 25° flexion. The limbs were equipped with intracortical pins in femur and tibia, and spherical retro-reflecting markers were glued on the pins. Objective knees movements were measured by means of a Motion Analysis® system (Motion Analysis Corporation, Santa Rosa, CA, USA). Two statistical analyses were performed. A single sample t-test was first used to verify the required 25? flexion. Then, a multivariate anova was performed to analyse the varus-valgus laxity under the fixed factors of measurement method and flexion of the knee.ResultsThe results for varus-valgus and total laxity of the clinician always exhibited a greater variability than objective measurements of the device. Test condition is a factor of grouping differences for Valgus and for global mediolateral laxity. Statistical analysis revealed that the objective measurement was able to show a difference between extension and 25° flexion for global mediolateral laxity, whereas the clinician was not.DiscussionThe clinician was relatively accurate in his manual evaluation. However, we demonstrated that a measurement device could clearly help clinician to exhibit differences in laxity. This can be very useful to compare a knee to itself in two successive conditions, e.g., before and after a surgery.  相似文献   

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