Ordinary Body Research Articles

Bone growth stimulators New tools for treating bone loss and mending fractures

In the new millennium, humans will be traveling to Mars and eventually beyond with skeletons that respond to microgravity by self-destructing. Meanwhile in Earth's aging populations growing numbers of men and many more women are suffering from crippling bone loss. During the first decade after menopause all women suffer an accelerating loss of bone, which in some of them is severe enough to result in "spontaneous" crushing of vertebrae and fracturing of hips by ordinary body movements. This is osteoporosis, which all too often requires prolonged and expensive care, the physical and mental stress of which may even kill the patient. Osteoporosis in postmenopausal women is caused by the loss of estrogen. The slower development of osteoporosis in aging men is also due at least in part to a loss of the estrogen made in ever smaller amounts in bone cells from the declining level of circulating testosterone and is needed for bone maintenance as it is in women. The loss of estrogen increases the generation, longevity, and activity of bone-resorbing osteoclasts. The destructive osteoclast surge can be blocked by estrogens and selective estrogen receptor modulators (SERMs) as well as antiosteoclast agents such as bisphosphonates and calcitonin. But these agents stimulate only a limited amount of bone growth as the unaffected osteoblasts fill in the holes that were dug by the now suppressed osteoclasts. They do not stimulate osteoblasts to make bone--they are antiresorptives not bone anabolic agents. (However, certain estrogen analogs and bisphosphates may stimulate bone growth to some extent by lengthening osteoblast working lives.) To grow new bone and restore bone strength lost in space and on Earth we must know what controls bone growth and destruction. Here we discuss the newest bone controllers and how they might operate. These include leptin from adipocytes and osteoblasts and the statins that are widely used to reduce blood cholesterol and cardiovascular damage. But the main focus of this article is necessarily the currently most promising of the anabolic agents, the potent parathyroid hormone (PTH) and certain of its 31- to 38-aminoacid fragments, which are either in or about to be in clinical trial or in the case of Lilly's Forteo [hPTH-(1-34)] tentatively approved by the Food and Drug Administration for treating osteoporosis and mending fractures.

Stress intensity factors of embedded elliptical cracks and an assessment of the ASME XI defect recharacterisation criteria

This paper considers aspects related to the calculation of the stress intensity factors of planar embedded defects in a solid under tension. The determination of stress intensity factor solutions using a modified body force method is described, this technique having certain advantages over existing finite element, boundary element and ordinary body force methods. Furthermore, comprehensive modified body force solutions are presented and discussed for a range of elliptical defect geometries. These solutions have then been used to asses the conservation of the recharacterisation procedure for defects of complex geometry described in Section XI of the ASME Boiler and Pressure Vessel Code. Maximum stress intensity factor values calculated using both the modified body force method and the ASME XI rules in conjunction with standard solutions are compared and contrasted. The results of this analysis show that, by and large, ASME XI is conservative and hence safe. However, geometries for which ASME XI provides non-conservative estimates have been encountered and, in certain circumstances, this may be a cause for concern.

GENERALIZED STEFAN LAW

We obtain and discuss the properties of the g-deformed Stefan law for the black body radiation of quon particles. We prove that if we consider adiabatic transformations with a particular value of η=VT3, the Stefan law is exactly the same as for the ordinary black body.

New physical model of multiplication-induced breakdown in MOSFETs

The thesis of this paper is that the mechanism of multiplication-induced breakdown is essentially different from what has previously been thought. Two consecutive phases of the breakdown: enhanced body effect (EBE) and parasitic bipolar action have to be distinguished. It is shown that the difference between the EBE and the ordinary body effect results from the fact that the body effect does not involve any electrical field, whereas EBE has to account for a nonzero field in the bulk, necessary to drive the substrate current. Similarly the bipolar action may be treated in terms of a parasitic bipolar transistor, but only on condition that the variable geometry and unconventional mode of biasing of the base are taken into account. It has been found that the size of the base increases considerably with V DS. In addition, the base bias V be is not equal to V sub − V sub = R sub I sub becomes entirely constant) but rather to V sub + δΨ − V SB, where δΨ has been explicitly related to the substrate current I sub. The new physical model of multiplication-induced breakdown has been verified and confirmed according to numerical simulation results. Furthermore, the analytical predictions based on it agree very closely with measured drain and substrate current characteristics.

High-frequency approximation to the nongeometricalS* arrival

abstractWhen an explosive point source is buried less than one wavelength from the free surface in a perfectly elastic, homogeneous, isotropic half-space, a very strong non-geometric arrival, tentatively denoted as S* by Hron and Mikhailenko (1981), exists in the reflected shear wave field. It has all basic characteristics of an ordinary shear body wave (linear polarization, transverse particle motion, and shear wave velocity) and, as such, it can be also reflected or transmitted upon incidence at an interface according to the rules governing ordinary body waves. Because of its very strong amplitude which at most epicentral distances exceeds even the amplitude of a direct P wave, the S* arrival is undoubtedly responsible for a large part of the shear wave energy content seen in the seismic records in oil exploration, which deals almost exclusively with shallow explosive sources. In our paper, we develop a high-frequency approximation to the S* arrival applying a saddle-point method to the integral representing a shear wave reflected from the free surface due to the incidence of a spherical longitudinal wave radiated by the shallow point source. Numerical results presented in the paper show that our high-frequency approximation preserves all basic features of the S* arrival, thereby making it suitable for easy incorporation into any synthetic seismogram computation based on the ray approach.

Numerical modeling of nongeometrical effects by the Alekseev-Mikhailenko method

When the Alekseev-Mikhailenko method was used for the exact numerical solution of Lamb's problem, a new strong nongeometrical arrival, denoted by S *, was detected in the synthetic seismograms computed for a P point source located in the proximity of the free surface. Strong dependence of the amplitude of the S * arrival on the depth of the source is seen in computed seismograms. It is shown that under favorable circumstances, i.e., when the source is less than one wavelength from the free surface, the S * arrival may be stronger than ordinary body waves at the same depth. This may be particularly important for studies of the seismic wave fields in oil exploration, where explosive sources are close to the surface. We show that the S * arrival, which features a linear polarization and propagates with the shear wave velocity, may be interpreted as a result of interaction between inhomogeneous plane waves in the integral representation of the P point source, and the free surface. Mathematically, the S * arrival corresponds to the saddle point contribution of the integral along the branch cut originating at the horizontal slowness p = α/β ( α, β indicate P - and S -phase velocities, respectively). This branch cut must be considered when the saddle point approximation to the Weyl-Sommerfeld integral for a shallow P point source is used. Existence of another nongeometrical effect, namely the nonzero vertical component of the converted PS wave reflected from the free surface at normal incidence, is also shown. In our opinion, this arrival can be easily explained by higher order terms in the corresponding ray series. The prominence of both nongeometrical effects suggests they should be incorporated into any synthetic seismogram computations carried out for shallow explosive sources.

Equations of motion of a black hole in the quasistationary approximation

The motion of a black hole subject to external influences as observed by a distant observer is considered. Zerilli's equations are used to find the displacement of the black hole and the structure of the metric in the presence of other gravitating bodies. It is shown that in a region in which the curvature of space is small the contribution of the field of the accelerated black hole has the same form as the field of an ordinary body and that the motion of the black hole in the quasistationary approximation takes place in accordance with the laws of Newtonian dynamics.

Surgical-orthodontic approach to skeletal Class III malocclusion: Analysis of 45 cases with evaluation of curved oblique osteotomy and sliding osteotomy

A curved oblique osteotomy in which the ascending ramus was cut obliquely on a curved line from its anterior border to the angle was used for the treatment of 29 patients with skeletal Class III malocclusion, and 16 other patients were corrected by either an ordinary body osteotomy or a sliding osteotomy in the first premolar region. Both curved oblique osteotomy and sliding osteotomy could easily be performed with a Stryker's reciprocating saw, and osseous healing at the sites of surgery was rapid as a large area of intimate bony contact between the segments was obtained. The resulting profile and skeletal changes studied by cephalograms were excellent, with no significant relapse, and recovery of a stable occlusion was attained. The combined approach with orthodontists which included thorough analysis of each patient, preoperative alignment of the dental arches and postoperative care was essential for obtaining the best results.

Prediction of spirometric values in patients with scoliosis.

The prediction of normal spirometric values requires a measure of the non-deformed body height of scoliotic patients. The arm-span method has been used for estimating the non-deformed body height in spite of the fact that opinions about the normal relationships between body height and arm span differ. In order to minimize the error of estimation of non-deformed body height, the normal relationships between body height and arm span were determined for 91 males and for 118 females of ordinary body stature, varying age (5-78 years), and Swedish origin. The body-height/arm-span relationships were described by linear regression equations taking age into account. The results indicate significant sex and age differences in the arm-span/height ratio. Multiple regression equations including arm span and age as regressors were used to calculate the non-deformed body height in scoliotic patients. The arm-span method was compared with the method using the degree of lateral curvature of the spine for calculation of non-deformed body height of scoliotic subjects. The arm-span method resulted in a correction of body height and predicted spirometric values that agreed closely with those obtained by the method using the degree of curvature of the spine. The two methods may be used alternatively. In accordance with earlier reports, the predicted spirometric values were underestimated when the measured body height was used.

A theory of composites modeled as interpenetrating solid continua

The differential equations and boundary conditions describing the behavior of a finitely deformable, heat-conducting composite material are derived by means of a systematic application of the laws of continuum mechanics to a well-defined macroscopic model consisting of interpenetrating solid continua. Each continuum represents one identifiable constituent of the N-constituent composite. The influence of viscous dissipation is included in the general treatment. Although the motion of the combined composite continuum may be arbitrarily large, the relative displacement of the individual constituents is required to be infinitesimal in order that the composite not rupture. The linear version of the equations in the absence of heat conduction and viscosity is exhibited in detail for the case of the two-constituent composite. The linear equations are written for both the isotropic and transversely isotropic material symmetries. Plane wave solutions in the isotropic case reveal the existence of high-frequency (optical type) branches as well as the ordinary low-frequency (acoustic type) branches, and all waves are dispersive. For the linear isotropic equations both static and dynamic potential representations are obtained, each of which is shown to be complete. The solutions for both the concentrated ordinary body force and relative body force are obtained from the static potential representation.

II The age of menarche in Finnish girls in 1969

The material consisted of data on 8,111 girls from primary and secondary schools in different districts of Finland. The investigation was carried out during 1969 and the girls were from 10 to 20 years of age.By means of the probit analysis method it was found that the mean value of the menarcheal age for the whole country was 13.16 ± 0.02 years and standard deviation 1.13 years. With few exceptions, menarche occurred between 10 and 16 years of age.The trend towards a lower menarcheal age since the late 19th century was found to continue. The rate of decline in the age of menarche was estimated, on the basis of earlier studies, to be about 6 months per decade. The causes of this trend were discussed and the conclusion drawn was that its pace corresponds to that of the rise in the general standard of living.The comparison of constitutional types calculated according to the height/weight ratio showed that the menarche of asthenic girls occurred 11.4 months later than that of girls with a normal height/weight ratio, and that the pyknic type started menstruation 4.8 months later than the normal. The age at menarche of the girls with an ordinary body build was just under 13 years.Dependence upon geographical environments could be shown in that the menarcheal age of the girls living in the capital was 5.2 months lower than that of girls living in the inland districts. The menarcheal age of the girls living in the coastal districts and representing small‐town dwellers did not differ significantly from the girls resident in the capital.A comparison between the social groups revealed an almost significant difference of 2.2 months in the age of menarche between the girls of groups I and II.The menarcheal age of the primary school pupils was 5.5 months higher than that of secondary school pupils.The mean menarcheal age of the mothers, whose mean age was 40 years at the time of the investigation, was 13.88 ± 0.02 calculated on the basis of recollected data. Comparisons by constitutional types, geographical place of residence and social groups revealed the same differences among the mothers as among the girls.

Tetanic Force and Shortening in Locust Flight Muscle

ABSTRACT The maximum tetanic force and shortening was studied in the isolated, dorsal-longitudinal muscle of the hindwings of the desert locust (Schistocerca gregaria). The muscle tended to die when isolated in artificial salines but after penicillin had been added it survived well for more than 8 hr. at 32° C. The cause is discussed. The flight muscle is very sensitive to lack of oxygen and, at room temperature and above, it is necessary to perfuse the main tracheae with air. No difference was observed between indirect and direct stimulation. The natural activity consists of repetitive twitches. Tetanic contractions always caused rapid fatigue and tended to injure the muscle, partly because of excessive shortening (‘delta state’) and partly because the muscle ‘gave’ at the comparatively small total tension of 2-2·5 kg.cm.-2. The length-force diagram at 11° C. resembles that of ordinary skeletal muscle, but the maximum shortening (o-45L6) and the maximum isometric tension (1·6 kg.cm.-2) are smaller than in frog muscle at that temperature. As in mammahan muscle, the isometric tension increases much with temperature and was estimated indirectly as 3 kg.cm.-2 at 25° C. and 4 kg.cm.-2 at 35° C. The largest observed shortening was 0·55Lb. At ordinary body temperature, tension and work are of the’ same magnitude as in skeletal muscle of vertebrates. The flight muscle is less extensible than frog muscle and the maximum isometric force is produced at a lower I-band/sarcomere ratio (0-2). As in frog muscle, passive stretch only affects the I-bands, while the A-bands remain at constant length, at least in the fixed material used here. It is probable that the mechanical specialization of the flight muscle mainly concerns the sarcolemma and the other passive-elastic elements; the contractile elements do not seem to differ from ordinary muscle.

魚体のカタラーゼについて-I

1) Thermostability of catalase of liver extracts of poecilothermic animals namely five kinds of fresh-water fishes (cold water fishes: rain-bow trout and Oncorhynchus formosunus; semicold water fish: Plecoglossus altivelis; warm-water fishes: carp and crucian) was constrasted with that of homoesthermic animal, domestic fowl. 2) Stability of catalase of liver extracts in relation to temperature was found to vary considerably with species of the animals studied, and to stand in close relation with temperatures suited for leading their life. 3) Liver catalase of the cold-water fishes was stable at 20°C but inactivated slowly at 30°C and rapidly at 40°C. 4) The same of the semi-cold water fish, Plecoglossus altivelis, was stable at 30°C but inactivated slowly at 40°C and rapidly at 45°C. 5) On the other hand, a slight augmentation of activity of the warm water fishes was observed at 25°C and a much remarkable one at 30°-40°C, but followed by inactivation after 30-60 minutes' exposure. A rapid inactivation of it was evident from the start when experimented at 45°C. 6) Liver-extract of the domestic fowl was found continuously increasing it activity at 30°-40°C. Rapid activation of it took place at 45°-55°C but gradual inactivation appeared at heels after 60 minutes' lapse of time. Neither augmentation nor decrease in activity of the enzyme in question was observed at 60°C. 7) Liver catalase is extremely stable at temperatures wich are either optima for living or ordinary body temperatures of animals. But heating beyond the ranges tends to cause slow or rapid inactivation. Sometimes such treatment leads to appearent activation of the enzyme at first but it is bound to end in opposite direction. 8) Energies of inactivation are shown in Table 2.

THE TYPHUS FEVER OF MEXICO (TARBADILLO)

It will be recalled that Nicolle 1 and his associates recently have greatly advanced our knowledge of typhus fever by two achievements. First, it was shown that the disease could be transmitted to the chimpanzee by the injection of the blood of human patients, and in a similar way from the chimpanzee to the macacus monkey ( Macacus sinicus ). Strangely they were not able to infect the macacus directly with virulent human blood. Their second important result consists in the transmission of the disease from macacus to macacus by means of the ordinary body louse ( Pediculus testamenti ). From the epidemiologie conditions which prevail in Tunis they were able to rule out the flea and the bedbug as carrying agents. When the moneky has once been infected with the louse, they attempted to transfer the disease from animal to animal by means of injection from the first monkey, but the experiments resulted