Method of determining the colloidal status of the vitreous body

A new method for the quantitative estimation of the vitreous body colloidal state has been suggested. For realization of the method a fragment of the vitreous body and an equal volume of water are dried out, and the drying time is registered. The higher is the ratio between the drying time of the vitreous body fragment and water, the higher is the density of the vitreous body gel. The drying out of the vitreous body fragment and water on the analytical balance cups permits the registration of the drying out process in the time course. Thus some additional parameters are obtained that characterize the object studied more completely. The method can be used in experimental and clinical investigations of the vitreous body and other biological liquids.     

Equations of heat distribution within the body

A vector integral equation describing heat distribution within the body has been derived. The factors considered are heat conduction, forced convection via the circulatory system, environmental exchange, metabolic heat production, and change in heat content. The vector partial differential equation and alternative forms incorporating boundary conditions were also developed. A difference equation based on a first-order approximation to the fundamental equations was derived to form the basis of a model for heat distribution within the body. It has been shown that factors involving conduction and convection must be considered independently unless the temperature of the blood flowing from a region of the body is equal to the average temperature of the tissue in that region. If this relation between tissue and blood temperature does exist, only a single temperature from each eleeent is needed to describe the heat distribution. In this latter case, models which ascribe all heat transfer to “equivalent” conduction or to convection can give valid predictions.     

The integument of the Queensland fruit fly,Dacus tryoni (Frogg.)

Summary Testes of the Japanese freshwater turtle Clemmys japonica Temmnick et Schlegel were fixed in 3% potassium permanganate buffered to pH 7.2 with Veronal-acetate buffer, and thin sections of the tissue, embedded in epoxy Epon resin, were studied under the electron or light microscope.At the early stage of differentiation of the spermatid, the cytoplasm contains a few mitochondria provided with cristae which are oriented transversely or longitudinally. As the differentiation of spermatids proceeds, the mitochondrion has been modified into a cupshaped body with a wall consisting of several concentric layers. Such body has been referred to the mitochondrial lamellar body. The formation of such a body is mainly attributed to the mitochondrial cristae, and subsequently to the membrane system of the endoplasmic reticulum. In a more advanced stage of differentiation, the mitochondrial lamellar bodies appear wrapped around a bundle of tail filaments, and seem to present a very wide surface available for the localization of organized enzyme systems to facilitate the motion of spermatozoa.Prior to the formation of the mitochondrial lamellar bodies, the Golgi apparatus has been reorganized into a peculiar body with a floral appearance, consisting of numerous tubular elements, and revealing to be positive in PAS-reaction. The body has been designated as the tubular body which has never been demonstrated in any spermatogenic cells through animal kingdom.One to three tubules oval in cross section, approximately 430 × 700 Å in diameter, have been found in the nucleoplasm along the longitudinal axis of a greatly elongated, cone-shaped nucleus of the spermatid. The tubules open on the apex surface of the nucleus, but they are not encountered in the acrosome. A possible physiological significance of the tubules has been discussed in view of the function of the acrosomal tubules in the decapod and other species spermatozoa as well as on the basis of the metabolism of nucleus.This study was supported by Grant GM-8327 from the United States Public Health Service.We wish to express our gratitude to Dr. B. A. Afzelius, Wenner-Gren Institute, University of Stockholm, for his valuable suggestion to the present work.     

Climate change and size evolution in an island rodent species: new perspectives on the island rule

As stated by the island rule, small mammals evolve toward gigantism on islands. In addition they are known to evolve faster than their mainland counterparts. Body size in island mammals may also be influenced by geographical climatic gradients or climatic change through time. We tested the relative effects of climate change and isolation on the size of the Japanese rodent Apodemus speciosus and calculated evolutionary rates of body size change since the last glacial maximum (LGM). Currently A. speciosus populations conform both to Bergmann's rule, with an increase in body size with latitude, and to the island rule, with larger body sizes on small islands. We also found that fossil representatives of A. speciosus are larger than their extant relatives. Our estimated evolutionary rates since the LGM show that body size evolution on the smaller islands has been less than half as rapid as on Honshu, the mainland-type large island of Japan. We conclude that island populations exhibit larger body sizes today not because they have evolved toward gigantism, but because their evolution toward a smaller size, due to climate warming since the LGM, has been decelerated by the island effect. These combined results suggest that evolution in Quaternary island small mammals may not have been as fast as expected by the island effect because of the counteracting effect of climate change during this period.     

First descriptions of copepodid stages, sexual dimorphism and intraspecific variability of Mesocletodes Sars, 1909 (Copepoda, Harpacticoida, Argestidae), including the description of a new species with broad abyssal distribution

Mesocletodes Sars, 1909a encompasses 37 species to date. Initial evidence on intraspecific variability and sexual dimorphism has been verified for 77 specimens of Mesocletodes elmari sp. n. from various deep-sea regions, and ontogenetic development has been traced for the first time. Apomorphies are a strong spinule-like pinna on the mx seta that is fused to the basis, P2-P4 exp3 proximal outer seta lost, P1-P4 enp2 extremely elongated, furcal rami elongated, female body of prickly appearance, female P2-P4 enp2 proximal inner seta lost. Intraspecific variability involves spinulation, ornamentation and size of the body and setation and spinulation of pereiopods. Sexually dimorphic modifications of adult females include prickly appearance of the body, P1 enp exceeds exp in length, P1 coxa externally broadened, seta of basis arising from prominent protrusion, hyaline frills of body somites ornate. Sexual dimorphism in adult males is expressed in smaller body size, haplocer A1, 2 inner setae on P2-P4 enp2 and on P5 exp, P5 basendopodal lobe with 2 setae. Some modifications allow sexing of copepodid stages. The female A1 is fully developed in CV, the male A1 undergoes extensive modifications at the last molt. P1-P4 are fully developed in CV. Mesocletodes faroerensis and Mesocletodes thielei lack apomorphies of Mesocletodes and are excluded.     

A statistical test of unbiased evolution of body size in birds

Abstract.— Of the approximately 9500 bird species, the vast majority is small-bodied. That is a general feature of evolutionary lineages, also observed for instance in mammals and plants. The avian interspecific body size distribution is right-skewed even on a logarithmic scale. That has previously been interpreted as evidence that body size evolution has been biased. However, a procedure to test for unbiased evolution from the shape of body size distributions was lacking. In the present paper unbiased body size evolution is defined precisely, and a statistical test is developed based on Monte Carlo simulation of unbiased evolution. Application of the test to birds suggests that it is highly unlikely that avian body size evolution has been unbiased as defined. Several possible explanations for this result are discussed. A plausible explanation is that the general model of unbiased evolution assumes that population size and generation time do not affect the evolutionary variability of body size; that is, that micro- and macroevolution are decoupled, which theory suggests is not likely to be the case.     

Ribosome metabolism during the vitellogenic cycle of the mosquito, Aedes aegypti

Ribosome accumulation and synthesis in the fat body of the mosquito Aedes aegypti increased by approx. 4-fold during 18 h after the blood meal, consistent with the pattern of total RNA accumulation during the synthetic phase of the vitellogenic cycle. By 24-30 h after the blood meal, the accumulated ribosomes began to be degraded, and the total RNA content in the fat body eventually returned to previtellogenic levels. A method has been developed for isolation of ribosomal subunits from fat body, and the ribosomal proteins have been shown to have properties similar to those from cultured Aedes albopictus cells by two-dimensional polyacrylamide gel electrophoresis. Proteins S1, S10, and A from the small ribosomal subunit are phosphorylated when fat body is incubated in Aedes saline in the presence of [32P]orthophosphate.     

An assessment of swinger techniques for the playground swing oscillatory motion

Much attention has been devoted to how playground swing amplitudes are built up by swinger techniques, i.e. body actions. However, very little attention has been given to the requirements that such swinger techniques place on the swinger himself. The purpose of this study was to find out whether different swinger techniques yield significantly different maximum torques, endurance and coordinative skills, and also to identify preferable techniques. We modelled the seated swinger as a rigid dumbbell and compared three different techniques. A series of computer simulations were run with each technique, testing the performance with different body rotational speeds, delayed onset of body rotation and different body mass distributions, as swing amplitudes were brought up towards 90°. One technique was found to be extremely sensitive to the timing of body actions, limiting swing amplitudes to 50° and 8° when body action was delayed by 0.03 and 0.3?s, respectively. Two other more robust techniques reached 90° even with the largest of these delays, although more time (and endurance) was needed. However, these two methods also differed with respect to maximum torque and endurance, and none was preferable in both these aspects, being dependent on the swinger goals and abilities.     

The unidirectional flagellar motor of Rhodobacter sphaeroides WS8 can rotate either clockwise or counterclockwise: characterization of the flagellum under both conditions by antibody decoration.

A variant of Rhodobacter sphaeroides WS8 has been isolated which when tethered has a cell body that rotates counterclockwise instead of clockwise. Antibody decoration in vivo has shown that the filament on the variant has handedness opposite to that of the normal form. In both cases the cell body is pushed by the rotating flagellum.     

Modelling of the biomechanics of posture and balance

A technique for studying the relationship of posture to balance has been developed. To investigate this relationship quantitatively, the human body was treated as consisting of 11 rigid body segments, each with six degrees of freedom. A bilateral Selspot II/TRACK data acquisition system provides position and orientation kinematic data for estimation of the trajectories of the individual body segment centers of gravity. From these, the whole body center of gravity is estimated and compared to concurrent force plate center of force data. Center of gravity and center of force excursions agree where dynamics are not significant. The technique may be employed to study quiet stance, response to postural disturbances, or the initiation and coordination of complex movements such as gait.     

Features of the structure of arteries of the lower extremities in man

A comparative investigation has been performed on structural peculiarities of muscle arteries having various caliber in the lower extremities and in the anterior thoracic wall (section material, 40 observations). An essential predominance of the muscle tunic thickness and deterioration of blood supply has been stated in the arterial wall and in the distal parts of the lower extremities. The structural peculiarities revealed in the arteries of the extremities are connected with functional conditions of blood supply in the zone at the vertical position of the human body (orthostatic arterial hypertension).     

A critical reappraisal of the fossil record of the bilaterian phyla

It has long been assumed that the extant bilaterian phyla generally have their origin in the Cambrian explosion, when they appear in an essentially modern form. Both these assumptions are questionable. A strict application of stem- and crown-group concepts to phyla shows that although the branching points of many clades may have occurred in the Early Cambrian or before, the appearance of the modern body plans was in most cases later: very few bilaterian phyla sensu stricto have demonstrable representatives in the earliest Cambrian. Given that the early branching points of major clades is an inevitable result of the geometry of clade diversification, the alleged phenomenon of phyla appearing early and remaining morphologically static is seen not to require particular explanation. Confusion in the definition of a phylum has thus led to attempts to explain (especially from a developmental perspective) a feature that is partly inevitable, partly illusory. We critically discuss models for Proterozoic diversification based on small body size, limited developmental capacity and poor preservation and cryptic habits, and show that the prospect of lineage diversification occurring early in the Proterozoic can be seen to be unlikely on grounds of both parsimony and functional morphology. Indeed, the combination of the body and trace fossil record demonstrates a progressive diversification through the end of the Proterozoic well into the Cambrian and beyond, a picture consistent with body plans being assembled during this time. Body-plan characters are likely to have been acquired monophyletically in the history of the bilaterians, and a model explaining the diversity in just one of them, the coelom, is presented. This analysis points to the requirement for a careful application of systematic methodology before explanations are sought for alleged patterns of constraint and flexibility.     

An assessment of swinger techniques for the playground swing oscillatory motion

Much attention has been devoted to how playground swing amplitudes are built up by swinger techniques, i.e. body actions. However, very little attention has been given to the requirements that such swinger techniques place on the swinger himself. The purpose of this study was to find out whether different swinger techniques yield significantly different maximum torques, endurance and coordinative skills, and also to identify preferable techniques. We modelled the seated swinger as a rigid dumbbell and compared three different techniques. A series of computer simulations were run with each technique, testing the performance with different body rotational speeds, delayed onset of body rotation and different body mass distributions, as swing amplitudes were brought up towards 90°. One technique was found to be extremely sensitive to the timing of body actions, limiting swing amplitudes to 50° and 8° when body action was delayed by 0.03 and 0.3 s, respectively. Two other more robust techniques reached 90° even with the largest of these delays, although more time (and endurance) was needed. However, these two methods also differed with respect to maximum torque and endurance, and none was preferable in both these aspects, being dependent on the swinger goals and abilities.     

Collective movement of ions in the cytoplasm

A theoretical model of propagation in the cytoplasm of self-consistent electromagnetic waves of the millimeter-infrared range has been developed, cytoplasmic ions surrounded by water ??coats?? being the main carriers of these waves. It has been discovered that not only own long-wavelength transverse oscillations, but also longitudinal waves that cannot leave the cytoplasm can exist in tissues of living organisms. Frequencies and logarithmic decrements of such perturbations have been found, and it is shown that these frequencies are close to those of ion oscillations inside the ??coats.?? Passage of laser radiation in bioobjects at the indicated frequencies has been analyzed, revealing bands of body impenetrability for waves. A new mechanism of swinging of cytoplasm own oscillations is proposed, based on the existence of an extreme border of the ion movement area. It has been shown that with this mechanism, the electric field amplitude for the longitudinal waves is six to seven orders of magnitude greater than the Planck fluctuation level.     

The effect of seed traits on geographic variation in body size and sexual size dimorphism of the seed‐feeding beetle Acanthoscelides macrophthalmus

Explaining large‐scale patterns of variation in body size has been considered a central question in ecology and evolutionary biology because several life‐history traits are directly linked to body size. For ectothermic organisms, little is known about what processes influence geographic variation in body size. Changes in body size and sexual size dimorphism (SSD) have been associated with environmental variables, particularly for Bruchinae insects, which feed exclusively on seeds during the larval stage. However, the effect of important seed traits on body size variation has rarely been investigated, and whether SSD varies substantially among populations within bruchine species is poorly known. Using the seed‐feeding beetle Acanthoscelides macrophthalmus infesting its host plant Leucaena leucocephala, we investigated whether specific seed traits (hardness, size, water content, carbon/nitrogen ratio, and phenolic content) were determinant in generating geographic variation in body size and SSD of A. macrophthalmus. We also examined the relationships between body size and SSD with latitude and altitude. The body size of both sexes combined was not related to latitude, altitude, and any of the physical and chemical seed traits. However, the female body size tended to vary more in size than the males, generating significant variation in SSD in relation to latitude and altitude. The females were the larger sex at higher latitudes and at lower altitudes, precisely where seed water content was greater. Therefore, our results suggest that water content was the most important seed trait, most severely affecting the females, promoting geographic variation in SSD of A. macrophthalmus.     

The fate and possible role of arylphorin during the metamorphosis of Mamestra brassicae.

1. Arylphorin, one of the storage proteins has been isolated from the hemolymph of Mamestra brassicae. 2. It has been established that Mamestra arylphorin is the most similar to manducin from among the known storage proteins of other species. 3. A rabbit polyclonal antibody has been developed against arylphorin, and its concentration changes have been determined quantitatively by ELISA in the hemolymph and fat body from the 1st day of the last larval instar to the 3rd day of the imago stage. 4. Histological sections were made on each day during the investigated period and it was shown by immunohistochemical methods that the main quantity of arylphorin was accumulated in the storage protein granules of the fat body and it could be detected even in the imaginal fat body. 5. The uptake of arylphorin by the fat body is induced by 20-hydroxyecdysone. 6. During differentiation of the imaginal cuticle arylphorin is incorporated first in the epidermal cells and it is built in the endocuticular layer of the integument thereafter.     

Regulation of destructive processes occurring in the body during senescence and in oncogenesis: A hypothesis

A hypothesis has been put forward according to which destructive processes occurring in the body during senescence and in oncogenesis are regulated by an atavistic mechanism of apical dominance described by plant physiologists. This mechanism is inherited from the first on Earth metazoans that behaved the mode of life attached to benthos and to underwater objects and were modular.     

Body mass is less important than bird order in determining the molecular rate for bird mitochondrial DNA

A negative relationship between body mass and molecular evolution rates has been suggested, and recently a correlation equation has been published based on mitochondrial genomic data of 475 bird species and their body masses. Here, we re‐analysed these data and show that the bird order as a proxy of monophyletic groups was a stronger predictor of the molecular rate than the body mass. We provide order‐specific molecular substitution rates. Only three orders (Galliformes, Gruiformes, Pelecaniformes) showed a very clear negative correlation, and specific correlation equations are given for these. The molecular rates of bird orders differed strongly at similar mean body masses, and we suggest that the previously described trend across all birds may arise as smaller species also tend to have characteristic life histories, namely faster turnover of generations, higher fecundity and shorter lifespans.     

Investigating the effects of external fields polarization on the coupling of pure magnetic waves in the human body in very low frequencies

In this paper we studied the effects of external fields' polarization on the coupling of pure magnetic fields into human body. Finite Difference Time Domain (FDTD) method is used to calculate the current densities induced in a 1 cm resolution anatomically based model with proper tissue conductivities. Twenty different tissues have been considered in this investigation and scaled FDTD technique is used to convert the results of computer code run in 15 MHz to low frequencies which are encountered in the vicinity of industrial induction heating and melting devices. It has been found that external magnetic field's orientation due to human body has a pronounced impact on the level of induced currents in different body tissues. This may potentially help developing protecting strategies to mitigate the situations in which workers are exposed to high levels of external magnetic radiation.     

Maternal care in the soft tick Antricola marginatus

Among spiders, scorpions, and whip spiders, a common type of maternal care consists of females carrying newly hatched offspring on their body for a few days until they are able to live independently. While this maternal care has been suggested to occur in different argasid tick species, it has been recorded only once, for Antricola marginatus in Cuba; however, this earlier record only superficially mentioned the occurrence of this behavior, with no further details. Here we report the occurrence of maternal care in the argasid tick A. marginatus under natural conditions in a cave at Yucatan, Mexico, where 8 A. marginatus females, while walking on bat guano, had their body entirely covered by a mean number of 305 ± 112 conspecific unfed larvae (range: 105-466). Larvae covered the entire idiosoma of the female tick, where they were motionless or displayed just slight movement. This result substantially expands the number of unique characters that have been found only in Antricola spp. ticks, when compared to the other tick genera. Our findings also indicate that maternal care evolved independently in different taxa of Arachnida, since it has been reported for species of Araneae, Scorpiones, and Amblypygi, and here for an Acari species.