bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of Ovarian Hypertrophy Under Experimental Conditions
Authors: Lipschütz Alexander 
Published: April 2021

ABSTRACT
The number of young ova in hypertrophied or increased ovarian fragments is reduced, sometimes highly reduced. This phenomenon has been seen in five experiments on young rabbits.
It is not very likely that the diminution is an apparent one due to the increased volume of the ovarian fragment.
Ovarian hypertrophy is not due to new formation of young ova but to follicular development.
The diminution of the number of young ova is explained by the fact that in an ovarian fragment a relatively increased number of young ova are used for follicular development.
It is very probable that the increase of follicular development, as taking place in an ovarian fragment and causing hypertrophy of the latter, is due to some general factor possibly to some substance available in the body in a given amount.
The ovarian fragment which alone remains in the body, reveals a tendency to cystic degeneration ; hypertrophy is in some cases nothing else than increase in volume by formation of big follicular cysts.
In five young rabbits fifteen ovaries from animals mostly of the same litters were subcutaneously engrafted. The grafts disappeared without any exception, in any case two months after the operation. In view of the great facility with which ovarian grafts generally take in homoiotransplantation, these negative results though not proving make it probable that the taking of the ovarian graft is rendered difficult when the ovaries in situ are present and use the substances as necessary for follicular development.
In three out of six cases of rabbits containing hypertrophied ovarian fragments the uterus was normal ; the fact that the uterus was less developed in the remaining cases might be explained by the long latent period as necessary till the threshold quantity of hormones can be produced by the ovarian fragment.
I am much indebted to my former co-worker Dr Karl Wagner, now Professor of Histology at the University of Kowno, for the sections for figs. 1 to 10 and 13 to 17; to Dr H. E. V. Voss for the sections for fig. II ; and to my friend Sergej Všnjakov for the photographs.
Modern Conceptions of Blood Clotting
Authors: Pickering J. W. 
Published: April 2021

ABSTRACT
Despite the large number of researches which have been made on blood coagulation, no single one of the many theories advanced satisfies the criterion of a tenable hypothesis in which all known facts should be correlated.
A better understanding of the fluidity and clotting of blood should lead to important results. On the practical side, we may hope for the elucidation of thrombosis—the formation of clots in the vessels—of the lack of coagulability in hæmophilia, of the changes in plasma during shock, and of the fatal intra-vascular clotting caused by certain snake venoms. On the theoretical side, light should be thrown on the reactions of colloids, on the mechanisms of immunity and of susceptibility, and possibly on the problems of genetics, as hæmophilia is transmitted from parent to offspring, and the existence of homologous bloods often depends on family relationship.
In this paper the current theories of blood coagulation will be reviewed briefly from the standpoint of investigations made in collaboration with my friends Drs Hewitt, de Souza, and Taylor,1-9 and evidence for a simpler view will be presented.
The Oviposition Responses of Calandra Granaria Linn
Authors: Eastham L. E. S. , McCully Sheila B. 
Published: April 2021

ABSTRACT
This investigation was undertaken following the survey into the incidence of infestation of stored cereals by insects (Munro, 1940), and forms part of a comprehensive research programme initiated by that author into the problems of the biology and control of grain weevils.
On the Behaviour of Wireworms of the Genus Agriotes Esch. (Coleoptera, Elateridae)
Authors: Lees A. D. 
Published: April 2021

ABSTRACT
Humidity reactions have recently been demonstrated in a number of terrestrial arthropods. In several instances–for example in Locusta migratoria (Kennedy, 1937), Culex fatigans (Thomson, 1938), Blatta orientalis (Gunn & Cosway, 1938), Tenebrio molitor (Pielou & Gunn, 1940) and in Pediculus humanus corporis (Wigglesworth, 1941)–it has been shown that such responses lead to the avoidance of moist air, a type of behaviour which is not easily associated with any specific physiological requirements. On the other hand, certain animals such as woodlice which are known to possess little capacity to resist desiccation, avoid dry, and aggregate in humid air (Gunn, 1937; Waloff, 1941); this type of behaviour is clearly of some adaptive significance.
Some Experiments on the Microscopical Demonstration of Zymohexase in Animal Tissues
Authors: Allen R. J. L. , Bourne G. H. 
Published: April 2021

ABSTRACT
The presence in extracts of animal tissues and yeast of an enzyme catalysing the cleavage of hexosediphosphate (fructofuranose-1:6-diphosphate) into two molecules of triosephosphate was demonstrated by Meyerhof & Lohmann (1934a):
Experimental Production of Atrophied and Partly Deficient Limbs (Phocomelias) in the Axolotl Embryo*
Authors: Brandt Walter 
Published: April 2021

ABSTRACT
The many different types and variations of deformities of limbs in animals and man are usually described and grouped from the morphological or genetical point of view. A very few biological experiments have been done for the purpose of elucidating the causes which produce special types of deformities in the embryo.
The Echolocation Calls of the Spotted Bat Euderma Maculatum are Relatively Inaudible to Moths
Authors: Fullard James H. , Dawson Jeff W. 
Published: April 2021

ABSTRACT
Previous studies of the spotted bat Euderma maculatum have demonstrated that this bat emits echolocation calls that are lower in frequency, shorter in duration and fainter in intensity compared with those of most other insectivorous bats, acoustic characteristics which should render it less conspicuous to eared moths. We tested this prediction by monitoring electrophysiologically the ears of sympatric noctuoid (noctuid, arctiid and notodontid) moths in a site in western Canada. Auditory threshold curves demonstrate that most of the moths tested are less responsive to the calls of Eu. maculatum than to those of another sympatric bat, Eptesicus fuscus. Playbacks to moth ears of pre-recorded search-and approach-phase echolocation calls of Eu. maculatum and Ep. fuscus further demonstrate that the calls of Eu. maculatum are poorly detectable to moths and, in some cases, completely inaudible. We estimate that, in the wild, an average noctuoid moth would detect the calls of Eu. maculatum at distances of less than 1 m as opposed to the calls of Ep. fuscus which should be first heard at distances of 20–25 m. Although most moths are unable to adequately hear Eu. maculatum, the observation that two individuals possessed ears sensitive to this bat’s calls suggests the existence of auditory pre-adaptation to this type of echolocation.
Locomotor Design Of Dolphin Vertebral Columns: Bending Mechanics And Morphology Of Delphinus Delphis
Authors: Long John H. , Pabst D. Ann , Shepherd William R. , Mclellan William A. 
Published: April 2021

ABSTRACT
The primary skeletal structure used by dolphins to generate the dorsoventral bending characteristic of cetacean swimming is the vertebral column. In the vertebral column of the saddleback dolphin Delphinus delphis, we characterize the static and dynamic mechanical properties of the intervertebral joints, describe regional variation and dorsoventral asymmetries in mechanical performance, and investigate how the mechanical properties are correlated with vertebral morphologies. Using a bending machine that applies an external load (N m) to a single intervertebral segment, we measured the resulting angular deformation (rad) of the segment in both dorsal extension and ventral flexion. Intervertebral segments from the thoracic, lumbar and caudal regions of the vertebral column were tested from five individuals. Using quasi-static bending tests, we measured the initial (low-strain) bending stiffness (N m rad−1) as a function of segment position, direction of bending (extension and flexion) and sequential cutting of intervertebral ligaments. We found that initial bending stiffness was significantly greater in the lumbar region than in adjacent thoracic and caudal regions, and all joints were stiffer in extension than in flexion. Cutting the interspinous ligaments significantly lowered the initial bending stiffness. Stiffness in extension is predicted (r2=0.554) by the length and width of the intervertebral disc and the length of the cranial vertebral body in the segment. Stiffness in flexion is predicted (r2=0.400) by the width of the nucleus pulposus, the length of the caudal vertebral body in the segment and the height of the transverse processes from the ventral surface of the vertebral body. We also performed dynamic bending tests on intervertebral segments from the lumbo-caudal joint and the joint between caudal vertebrae 7 and 8. Dynamic bending stiffness (N m rad−1) increases with increasing bending amplitude and is independent of bending frequency. Damping coefficient (kg m2 rad−2 s−1) decreases with increasing bending amplitude and frequency. Resilience (% energy return) increases from approximately 20 % at low bending amplitudes (±0.6 °) to approximately 50 % at high bending amplitudes (±2.9 °). Based on these findings, the dolphin’s vertebral column has the mechanical capacity to help control the body’s locomotor reconfigurations, to store elastic energy and to dampen oscillations.
Rates of Rewarming, Heart and Respiratory Rates and Their Significance for Oxygen Transport During Arousal From Torpor in the Smallest Mammal, the Etruscan Shrew Suncus Etruscus
Authors: Fons Roger , Sender Susanne , Peters Thomas , Jürgens Klaus D. 
Published: April 2021

ABSTRACT
We investigated the process of rewarming from torpor with respect to respiratory and circulatory oxygen transport properties in the smallest mammal, the Etruscan shrew Suncus etruscus. In seven adult Etruscan shrews with a mean body mass of 2.4 g, torpor was induced by deprivation of food and a cold environment. During arousal from torpor at an ambient temperature of 22 °C, the shrews actively rewarmed from the lowest mean (±S.D.) body temperature (Tb) of 12.1±1.2 °C to 20 °C at a rate of 0.43±0.14 °C min−1, from 20 to 24 °C at a rate of 0.8 °C min−1, and from 24 to 36 °C at a rate of 1.1±0.1 °C min−1. The mean rate from 12 °C to normothermia amounted to 0.83 °C min−1, which is among the highest values recorded in mammals. During rewarming, the heart rate increased exponentially (Q10=2.2) from 100 to 800–1200 min−1, whereas the respiratory rate increased linearly from 50 to 600–800 min−1. These rates are higher than the heart and respiratory rates reported for other small mammals at the same Tb.
The fraction of brown adipose tissue (BAT) was 9.2±1.6 % of body mass, which is higher than in any other mammal. Up to a body temperature of approximately 17 °C, the heat for rewarming was mainly produced in the BAT; above this value, considerable activity of the skeletal muscles enhanced thermogenesis. Estimation of the mixed venous oxygen partial pressure showed that, at the tissue level, the rewarming process corresponds to heavy work conditions. The ventilatory system is adapted such that during rewarming, in addition to the appropriate oxygen transport capacity, there is also a capacity for hyperventilation.
Maturational Changes in Troponin T Expression, Ca2+-Sensitivity and Twitch Contraction Kinetics in Dragonfly Flight Muscle
Authors: Fitzhugh Gail H. , Marden James H. 
Published: April 2021

ABSTRACT
Maximum lift production and the thermal sensitivity of lift production increase dramatically during adult maturation of Libellula pulchella dragonflies. Here, we report that the mechanistic basis for this transition appears to involve a developmental change in protein expression, which alters the Ca2+-sensitivity of muscle activation and twitch contraction kinetics. The alternatively spliced Ca2+ regulatory protein troponin T (TnT) undergoes an isoform shift during adult maturation. Skinned (demembranated) fibers of mature flight muscle are up to 13 times more sensitive to activation by Ca2+ than skinned fibers from teneral (newly emerged adult) flight muscle, and their Ca2+-sensitivity is more strongly affected by temperature. Intact muscle from mature individuals has a shorter time to peak tension and longer time to half-relaxation during twitch contractions, which is consistent with a greater Ca2+-sensitivity of mature muscle. Because it becomes activated more quickly and relaxes more slowly, mature flight muscle is able to generate, with each twitch, more force per unit area than teneral muscle; this difference in force becomes greater at high temperatures. There do not appear to be any age-related differences in actomyosin crossbridge properties, since teneral and mature flight muscles do not differ in shortening velocity, tetanic tension or instantaneous power output during isotonic contraction. Thus, variation in TnT expression appears to affect the temperature-dependent Ca2+-sensitivity of muscle activation, which in turn affects the kinetics and force production of the twitch contractions used by dragonflies during flight. This cascade of effects suggests that maturational changes in the expression of TnT isoforms may be a key determinant of overall muscle and organismal performance.
On the Mechanism of Water Vapour Sorption From Unsaturated Atmospheres by Ticks
Authors: Gaede K. , Knülle W. 
Published: April 2021

ABSTRACT
The nascent salivary secretion of 41 partly dehydrated and unfed adult female Amblyomma variegatum, 5–8 months post-ecdysis, during water vapour uptake at 93.5 % relative humidity and 20 °C, had an osmolality of between 298.6 and 769.7 mosmol kg−1 (mean ± S.D. 470.3±85.8 mosmol kg−1). This range would allow water vapour uptake at relative humidities of approximately 98–99 %, but it would not suffice for lower relative humidities down to 80–85 %, the critical equilibrium humidity of A. variegatum. At this relative humidity (85 %), an osmolality of 9796 mosmol kg−1 is required for water vapour uptake. It is proposed that hydrophilic cuticle in the hypostome could play a role in water condensation and that the slightly hyperosmotic secretion of the agranular alveoli of the salivary glands might alter the water affinity at the adsorbing cuticle surface and release the adsorbed water. The water-enriched secretion would then be drawn into the mouth by the powerful suction of the pharynx. This hypothetical hydrophilic cuticle component of water vapour uptake in A. variegatum merits closer investigation. The sorption kinetics of A. variegatum support an additional ‘osmotic’ component of water vapour uptake at humidities near saturation.
A nanolitre osmometer particularly suited to sample volumes smaller than 5 nl was developed. This device does not require the transfer of fluid after collection, and its measurement range is extended beyond the 5 osmol kg−1 that can be measured using commercial apparatus.
Post-Dive Blood Lactate Concentrations in Emperor Penguins, Aptenodytes Forsteri
Authors: Ponganis P. J. , Kooyman G. L. , Starke L. N. , Kooyman C. A. , Kooyman T. G. 
Published: April 2021

ABSTRACT
In order to determine an aerobic diving limit (ADL) in emperor penguins (Aptenodytes forsteri), post-dive blood lactate concentrations were measured in penguins foraging at an isolated sea ice hole. Resting lactate concentrations were 1.2–2.7 mmol l−1. Serial samples revealed that lactate level usually peaked within 5 min after dives and that 7–12 min was required for lactate concentrations to decrease from 5–8 mmol l−1 to less than 2.5 mmol l−1. Post-dive lactate level was not elevated above 3 mmol l−1 for dives shorter than 5 min. Two-phase regression analysis revealed a transition at 5.6 min in the post-dive lactate level versus diving duration relationship. All dives longer than 7 min were associated with lactate concentrations greater than 5 mmol l−1. We conclude that the ADL in emperor penguins ranges between 5 and 7 min. These are the first determinations of post-dive lactate concentrations in any free-diving bird and are currently the only physiological assessment of an ADL in an avian species.
Design Complexity and Fracture Control in the Equine Hoof Wall
Authors: Kasapi Mario A. , Gosline John M. 
Published: April 2021

ABSTRACT
Morphological and mechanical studies were conducted on samples of equine hoof wall to help elucidate the relationship between form and function of this complex, hierarchically organized structure. Morphological findings indicated a dependence of tubule size, shape and helical alignment of intermediate filaments (IFs) within the lamellae on the position through the wall thickness. The plane of the intertubular IFs changed from perpendicular to the tubule axis in the inner wall to almost parallel to the tubule axis in the outer wall. Morphological data predicted the existence of three crack diversion mechanisms which might prevent cracks from reaching the sensitive, living tissues of the hoof: a mid-wall diversion mechanism of intertubular material to inhibit inward and upward crack propagation, and inner- and outer-wall diversion mechanisms that prevent inward crack propagation.
Tensile and compact tension fracture tests were conducted on samples of fully hydrated equine hoof wall. Longitudinal stiffness decreased from 0.56 to 0.30 GPa proceeding inwardly, whereas ultimate (maximum) properties were constant. Fracture toughness parameters indicated that no compromise results from the declining stiffness, with J-integral values ranging from 5.5 to 7.8 kJ m−2 through the wall thickness; however, highest toughness was found in specimens with cracks initiated tangential to the wall surface (10.7 kJ m−2). Fracture paths agreed with morphological predictions and further suggested that the wall has evolved into a structure capable of both resisting and redirecting cracks initiated in numerous orientations.
Larval Locomotion of the Lancelet Branchiostoma Floridae
Authors: Stokes M. Dale 
Published: April 2021

ABSTRACT
The ontogeny of locomotion in the Florida lancelet (Branchiostoma floridae) is described for the early developmental stages through to metamorphosis. Recently hatched larvae swam at speeds up to 1 mm s−1 using their epidermal cilia; this speed decreased to approximately 0.2 mm s−1 by 60 h after fertilization. Changes in cilia-powered fluid flow could be related to changes in the distribution and density of the epidermal cilia during development. Cilia-powered hovering was the dominant behaviour until metamorphosis. The amount of energy expended by ciliating larvae ranged from 10−9 to 10−11 W depending upon the age of the larvae and the model used for estimating the power output. The majority of the energy expended was in the ciliary sublayer next to the body. The first muscular movements were seen in larvae 16 h old. These simple flexions increased in complexity during the first 72 h until a complete undulatory (approximately sinusoidal) wave was propagated down the body in the adult manner. The frequency of undulatory beating increased to approximately 10 Hz during the first 48 h, and the larval head showed a large degree of yaw. Lancelet larvae were also capable of high-speed undulations 5–10 times faster than regular swimming motions. In contrast to ciliating larvae, the energy expended during undulation was at least an order of magnitude greater (10−8 to 10−6 W) and radiated beyond the ciliary sublayer.
Direct Measurement of Flow From the Posterior Lymph Hearts of Hydrated and Dehydrated Toads (Bufo Marinus)
Authors: Jones J. M. , Gamperl A. K. , Farrell A. P. , Toews D. P. 
Published: April 2021

ABSTRACT
Flow from the posterior lymph hearts of Bufo marinus was measured using Doppler flow probes. These probes were placed on the posterior vertebral vein and recorded flow as lymph was ejected from the heart. In resting, hydrated toads, mean lymph flow from one of the paired posterior lymph hearts was 25.9±4.9 ml kg−1 h−1, stroke volume was 8.9±1.4 μl kg−1 and lymph heart rate was 47.5±3.7 beats min−1. We estimate that, together, the paired posterior lymph hearts are capable of generating flows that are approximately one-sixtieth of the resting cardiac output. Mean peak systolic pressure developed by the posterior lymph hearts was 1.62±0.08 kPa. Simultaneous measurements of lymph heart pressure development and flow revealed that the outflow pore of the heart opened at a pressure of 0.71±0.04 kPa, approximately 113±5 ms into systole.
When toads were moderately disturbed, stroke volume increased by as much as fourfold with little change in lymph heart rate (&lt;5 beats min−1). When toads were dehydrated, lymph flow decreased by 70 % at 12 h and by 80 % at 24 h. Since there was only a modest non-significant decrease in lymph heart rate (30 %), this reduction in flow was attributed to decreases in stroke volume (approximately 80 %). Lymph heart flow and stroke volume returned to control values 30 min after adding water back into the experimental chamber. Stroke volume was clearly more important in regulating lymph flow than lymph heart rate under these conditions in Bufo marinus.
The Effect of Exercise-Induced Localised Hyperthermia on Tendon Cell Survival
Authors: Birch Helen L. , Wilson Alan M. , Goodship Allen E. 
Published: April 2021

ABSTRACT
Tendons that store energy during locomotion, such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon, suffer a high incidence of central core degeneration which is thought to precede tendon rupture. Although energy storage contributes to the efficiency of locomotion, tendons are not perfectly elastic and some energy is lost in the form of heat. Recent studies have shown that the central core of equine SDFT reaches temperatures as high as 45 °C during high-speed locomotion. In this study, we test the hypothesis that hyperthermia causes tendon cell death and results in tendon central core degeneration. Tendon fibroblasts cultured from the core of the equine SDFT were subjected to a temperature of 45 °C in an in vitro system for 0–180 min, and cell survival fraction was measured and compared with that for equine dermal fibroblasts and a commercial rat kidney fibroblast cell line (NRK 49F). Tendon fibroblasts were significantly more resistant to hyperthermia than NRK 49F cells after 30, 45 and 60 min of heating and significantly more resistant than dermal fibroblasts after 45 and 60 min of heating. After 10 min of heating at 45 °C, the tendon fibroblast cell survival fraction was 91±4 %, whereas heating for 10 min at 48 °C resulted in a drop in the cell survival fraction to 22±4 %. In conclusion, while temperatures experienced in the central core of the SDFT in vivo are unlikely to result in tendon cell death, repeated hyperthermic insults may compromise cell metabolism of matrix components, resulting in tendon central core degeneration.
The Flight Performance of A Damselfly Ceriagrion Melanurum Selys
Authors: Sato Machiko , Azuma Akira 
Published: April 2021

ABSTRACT
The local circulation method was applied to the free forward flight of the damselfly Ceriagrion melanurum Selys. The kinematic data used in the calculations were obtained by analyzing video-taped images of damselflies in free flight in a transparent container. The inclination of the stroke plane was smaller and the flapping amplitude was larger than those of dragonflies reported in other studies on odonate flight. However, the phase shift between the fore- and hindwings agreed with none of the previously reported patterns for damselflies: the forewings lead the hindwings by approximately a quarter-period. The calculated forces were within the expected range of error. The muscle-mass-specific power was between 40 and 80W kg−1. The vorticity distribution of trailing and shed vortices in the wake was also analyzed. Strong trailing vortices were observed at the wing tips, whereas shed vortices were concentrated near the wing root as the stroke switched direction.