The temperature dependence of sliding force, velocity, and unbinding force was studied on actin filaments when they were placed on heavy meromyosin (HMM) attached to a glass surface. A fluorescently labeled actin filament was attached to the gelsolin-coated surface of a 1-microm polystyrene bead. The bead was trapped by optical tweezers, and HMM-actin interaction was performed at 20-35 degrees C to examine whether force is altered by the temperature change. Our experiments demonstrate that sliding force increased moderately with temperature (Q(10) = 1.6 +/- 0.2, +/-SEM, n = 9), whereas the velocity increased significantly (Q(10) = 2.9 +/- 0.4, n = 10). The moderate increase in force is caused by the increased number of available cross-bridges for actin interaction, because the cross-bridge number similarly increased with temperature (Q(10) = 1. 5 +/- 0.2, n = 3) when measured during rigor induction. We further found that unbinding force measured during the rigor condition did not differ with temperature. These results indicate that the amount of force each cross-bridge generates is fixed, and it does not change with temperature. We found that the above generalization was not modified in the presence of 1 mM MgADP or 8 mM phosphate.
It is difficult to cure severe open fractures of the lower extremities due to the frequent occurrence of severe damage to soft tissues or blood vessels, as well as bone defects, and concomitant infection, such as osteomyelitis. If appropriate treatment is not performed, long-term complications, such as nonunion of the bone, intractable ulcers, or other disorders, may arise. Between 1993 and 2010, we reviewed the records of 27 patients, and 28 limbs were treated. A total of 31 free-tissue transfers were performed on these 28 limbs. In this study, we classified the degree of damage based on the operative appearance of the condition of the recipient vein. A state that was normal or near-normal was described as type I-normal. A vein that was buried under a scar, but was comparatively easy to detach and retained a moderate adventitia was classified as type II-moderate. A vein with close adhesion between the wall and the scar that was not easy to detach was described as type III-severe. We also examined the relationships between recipient vein type and each of the following: (1) concomitant injury, (2) bone reconstruction, (3) preoperative infection, (4) length of time from injury to reconstruction, (5) eventual reoperation, and (6) flap necrosis. The results showed that there was a statistically significant relationship between recipient vein type and each of the following: bone reconstruction, preoperative infection, eventual reoperation, and flap necrosis. The selection of recipient vein is a factor that greatly affects the outcome of reconstruction of open fractures of the lower extremities. It is important to preoperatively estimate the condition of recipient vein even though it is difficult to preoperatively assess the condition. In some cases, only recipient veins in poor condition can be found intraoperatively on the affected leg. Under such circumstances, a cross-leg flap or a vein graft should be performed without hesitation to use recipient veins in a better condition.
The transition from colostrum to mature milk leads to an increase in SM and a decrease in PC in the HM of preterm infants, along with a decrease in PL content. This is the first report to demonstrate the differences in PL composition in HM between mothers of preterm and term infants.
The oxidation and degradation that accompany high dose gamma irradiation in air for crosslinking and sterilization are important because they could affect the clinical performance of polyethylene total joint implants. We report a clinical case of a 1000 kGy gamma-irradiated, highly crosslinked ultra-high molecular weight polyethylene acetabular cup retrieved 24 years postoperatively. Performance evaluations included absorbed radiation dose, total wear penetration, average wear rate, crystallinity, oxidation, and equibiaxial tensile properties. A retrieved acetabular cup of the same grade of polyethylene but gamma-sterilized using a conventional dose was used as control. The highly crosslinked and control cups took in about 1300 and 30 kGy of radiation, respectively, as measured using a trans-vinylene index. Direct dimensional measurements revealed average wear rates of the highly crosslinked and control cups were 0.04 and 0.06 mm/year, respectively. The oxidation index of the highly crosslinked cup was very high (0.679), but equivalent to that of a 1000 kGy irradiated reference cup. The retrieved highly crosslinked cup showed much higher equibiaxial ultimate tensile strength than the retrieved control cup. Based on these observations, the increased wear resistance and equibiaxial tensile properties that resulted from extensive crosslinking in the presence of air were partially offset by the adverse effects caused by immediate oxidation during the process.
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