Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Snow”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1983

Field measurements in snow skiing injury research.

Field measurements during skiing experiments simultaneously recorded the complete excitation of the toe and heel of one foot, the absolute spatial orientation of the pelvis and the foot, muscle activity at the hip, knee and ankle and the complete rotation of the femur relative to the tibia across the knee in three test subjects. Data were transmitted from test subjects during the skiing experiments by a 100K bits-1. PCM-FM system and recorded in digital form. Analyses of field data show the magnitude of the loading applied to the lower extremity during normal skiing often exceeds the expected, quasi-static ultimate strength of the tibia. Anterior-posterior bending of approximately 600 Nm has been recorded during skiing without binding release or injury to the test subjects. The standard heel binding design can not effectively control the bending moment in the lower extremity during skiing. Longitudinal rotation across the knee was in-phase with, though not proportional to, the applied torsion at the foot by the ski.

Athletic Injuries↗
PubMed1985

A microcomputer controlled snow ski binding system--II. Release decision theories.

A hierarchy of release decision theories for both tibia fracture and knee ligamentous injury are defined and simulated on a computer. Moment loading data, recorded during actual skiing by the microcomputer-based ski binding system described in Part I, are processed by the various release decision theories. At the bottom of the hierarchy is the simplest theory which treats boot loading as quasi-static and compares moment components to threshold levels. Another stage of the hierarchy defines an analytic expression for a combined loading failure locus. Note that this is the first formulation of a combined loading release decision theory. Yet another stage of the hierarchy computes bone moments via dynamic system leg models. The various release decision theories are evaluated by comparing processed results to both pain and bone failure limits. For the data generated by the field tests conducted to date, the simplest release decision theory satisfied the retention requirement for pain limits in the presence of muscle activity for both torsion and forward bending. For pain limits in the absence of muscle activity the retention requirement was not satisfied however. Another result is that leg dynamics are significant. A final result is that combined loading considerations lead to a more conservative theory.

Athletic Injuries↗
PubMed1992

Prediction of the loading along the leg during snow skiing.

The complete force and moment of each cross section of the leg between the ski boot top and the knee during normal skiing were predicted from measurements of the force and moment under the toe and heel of the boot and the flexion of the ankle. The force and moment components predicted at the base of the boot were significantly different from those predicted at sites of potential injury at the boot top and the knee. The maximum torsional and maximum varus-valgus moments predicted at the knee over all subjects tested were 70 Nm and 149 Nm, which are within the estimated range of the ultimate strength of the knee without support from contracted muscles crossing the knee. Regression analyses were used to find the force components at the base of the boot that best predict the bending and torsional moments at the boot top and knee. The torsional moments at the boot top and knee are best predicted by the medial-lateral force at the toe. The varus-valgus moment at the boot top and knee are best predicted by the resultant medial-lateral force component at the base of the boot. The set of best predictors of the anterior-posterior bending moments at the boot top and knee includes the vertical force at the toe, the vertical force at the heel and the component of the total vertical force directed perpendicular to the leg.

Adult↗
PubMed2006

High-performance liquid chromatographic determination of chitin in the snow crab, Chionoecetes opilio.

A HPLC method was developed for the determination of glucosamine in crab shells. The amount of glucosamine residue can be used to estimate the amount of chitin in analyzed material. Crab samples were hydrolysed with 6M HCl at 100 degrees C for 13 h and the released glucosamine was determined by HPLC using refractive index (RI) detection. Separations were performed using an ODS-2 column with an isocratic mobile phase consisting of 10% methanol, 90% hexanesulfonate, pH 2.1. Glucosamine identification was carried out not only on basis of retention time, but also with respect to mass spectra, which were acquired by HPLC-MS.

Animals↗
PubMed2005

In vitro steroid production by adrenals and kidney-gonads from embryonic southern snow skinks (Niveoscincus microlepidotus): implications for the control of the timing of parturition?

In some mammalian species, hormones produced by the embryo(s) at the completion of development are involved in the cascade of events that result in parturition. Our overall aim was to determine whether a similar mechanism exists in viviparous reptiles. The alpine skink Niveoscincus microlepidotus provides a useful model for studies of gestation and parturition in viviparous reptiles as the completion of embryonic development and parturition are temporally separated; ovulation occurs in spring, embryonic development is completed by autumn, but parturition does not occur until the following spring. In this study, we determined how in vitro steroid hormone production by embryonic adrenals (progesterone, corticosterone, and testosterone) and mesonephric kidney-gonads (oestradiol and testosterone) varied during the later stages of gestation. We hypothesised that embryonic adrenals and kidney-gonads were capable of producing steroid hormones in vitro, and that the pattern of production would change as parturition approached, would be influenced by temperature, and would increase in the presence of corticotropin (ACTH) or pregnenolone, respectively. Embryonic adrenals and kidney-gonads were incubated with or without ACTH or the steroid precursor pregnenolone, respectively. Tissues were incubated for 3 h at either 16 or 24 degrees C (preferred body temperature of pregnant N. microlepidotus). Incubation medium was analysed for steroid hormones using radioimmunoassay. Low levels of progesterone were produced in vitro during the later stages of gestation when embryonic adrenals were incubated with ACTH. In vitro corticosterone production by embryonic adrenals also occurred, with greater production occurring when tissues were incubated at 24 degrees C. Testosterone was produced in vitro by both adrenals and kidney-gonads in March (late autumn when embryonic development was complete, but prior to parturition the following spring), with greater production at 16 degrees C. This peak in testosterone production coincided with differentiation and continuing growth of the hemipenes. Low levels of oestradiol were produced in vitro by embryonic kidney-gonads in March. These results provide some support for the hypothesis that corticosterone production by the embryonic adrenal may have a role in determining the timing of parturition in a viviparous reptilian species. Further research is needed to differentiate the activity of various tissues and steroid hormones in control of embryonic development, sexual differentiation, and the potential regulation of gestation and parturition in N. microlepidotus and other viviparous reptiles.

Adrenal Glands↗