The Anatomy of the Infra-red Sense Organ in the Facial Pit of Pit Vipers

1957 ◽  
Vol s3-98 (42) ◽  
pp. 219-234
Author(s):  
THEODORE H. BULLOCK ◽  
WADE FOX
Keyword(s):  
Sense Organ ◽  
Single Layer ◽  
Visible Spectrum ◽  
Nerve Endings ◽  
Size Spectrum ◽  
Broad Absorption ◽  
Fibre Size ◽  
Infra Red ◽  
Anatomical Adaptations ◽  
Sensory Endings

1. The histological composition of the sensory membrane in the facial pit of rattle-snakes (Crotalus spp.), the disposition of the nerve-trunks entering it, the fibre-size spectrum of the nerves, and the form of the sensory endings are described. 2. Between the two layers of extremely attenuated epidermis the principal constituent of the membrane is a single layer of specialized parenchyma cells with osmiophil, reticular cytoplasm. These are not regarded as sense cells but they react strongly and locally to degeneration of nerve-endings. 3. The axons enter through numerous trunks from three branches of the trigeminal nerve, from all sides of the membrane, providing a dense innervation. They lose their myelin, taper to about 1µ, then expand into flattened palmate structures which bear many branched processes terminating freely over an average area of about 1,500µ2, overlapping only slightly with adjacent units but leaving virtually no area unsupplied. This means there are from 500 to 1,500 axons ending per mm2, an estimate which agrees with the nerve-counts. No other form of ending was found. 4. The mode of the fibre-size spectrum lies in the region 5-7µ, diameter. 5. A transmission spectrum of the fresh membrane shows broad absorption peaks at 3 and 6µ and about 50% transmitted in other regions out to 16µ. The visible spectrum is at least 50% transmitted and probably much is lost by reflection. Strong absorption takes place at wavelengths shorter than 490µ 6. The anatomical adaptations of the sense organ are discussed, especially the concentration of warm receptor fibres, the thinness of the membrane, the extremely superficial position of the nerve-endings--all increasing sensitivity to caloric flux. The overhanging margins of the pit and the richness of supply are believed to permit directionality of reception. 7. It is suggested that the palmate form of the ending has a significance in permitting several independent local sub-threshold activity generators to coexist in the processes and in pooling their coincident, electrotonically spread potentials to influence the initiation of spikes which may take place at the junction of axon and palm.

Differing mechanisms of cold-induced changes in capillary supply in m. tibialis anterior of rats and hamsters

2002 ◽  
Vol 205 (6) ◽  
pp. 829-840 ◽  
Author(s):  
Durmus Deveci ◽  
Stuart Egginton
Keyword(s):  
Skeletal Muscle ◽  
Cold Acclimation ◽  
Oxygen Diffusion ◽  
Tibialis Anterior ◽  
Capillary Density ◽  
Disuse Atrophy ◽  
Diffusion Distance ◽  
Capillary Supply ◽  
Fibre Size ◽  
Anatomical Adaptations

SUMMARY The physiological, metabolic and anatomical adaptations of skeletal muscle to chronic cold exposure were investigated in Wistar rats (Rattus norvegicus), a species that defends core temperature, and Syrian hamsters (Mesocricetus auratus), which may adopt a lower set point under unfavourable conditions. Animals were exposed to a simulated onset of winter in an environmental chamber, progressively shortening photoperiod and reducing temperature from 12 h:12 h L:D and 22°C to 1 h:23 h L:D and 5°C over 4 weeks. The animals were left at 4°C for a further 4 weeks to complete the process of cold-acclimation. M. tibialis anterior from control (euthermic) and cold-acclimated animals of similar mass showed a significant hyperactivity-induced hypertrophy in the rat, but a small disuse atrophy in the hamster. Little evidence was found for interconversion among fibre types in skeletal muscle on cold-acclimation, and only modest differences were seen in activity of oxidative or glycolytic enzymes in either species. However, adjustments in Type II fibre size paralleled the muscle hypertrophy in rat and atrophy in hamster. Cold-induced angiogenesis was present in the rat, averaging a 28 % increase in capillary-to-fibre ratio (C:F) but, as this was balanced by fibre hypertrophy across the whole muscle, there was no change in capillary density (CD). In contrast, the C:F was similar in both groups of hamsters, whereas CD rose by 33 % in line with fibre atrophy. Within distinct regions of the m. tibialis anterior, there was a correlation between angiogenesis and fibre size in rats, in which oxygen diffusion distance increased, but not in hamsters, in which there was a reduced oxygen diffusion distance. Consequently, the change in C:F was greatest (39 %) in the glycolytic cortex region of the m. tibialis anterior in rats. We conclude that non-hibernator and hibernator rodents improve peripheral oxygen transport following cold-acclimation by different mechanisms. In rats, an increase in fibre girth was accompanied by a true angiogenesis, while the improved apparent capillary supply in hamsters was due to smaller fibre diameters. These responses are consistent with the strategies of resisting and accommodating, respectively, an annual fall in environmental temperature.

scholarly journals Light Absorption and Luminescence Properties of the Blend Poly(N-vinylcarbazole)/Poly(N-hexylthiophene)

2017 ◽  
Vol 26 (3) ◽  
pp. 269
Author(s):  
Nguyen Phuong Hoai Nam ◽  
Hoang Mai Ha ◽  
Ngo Trinh Tung ◽  
Dang Dinh Long ◽  
Nguyen Khac Quan ◽  
...  
Keyword(s):  
Conducting Polymers ◽  
Light Absorption ◽  
Electronic Devices ◽  
Ultra Violet ◽  
Luminescence Properties ◽  
Broad Absorption ◽  
Infra Red

We have investigated the enhancement absorption light and luminescence properties of the blend conducting polymers using poly(N-vinylcarbazole) and poly(N-hexylthiophene). The optimized material showed a broad absorption in the region of ultra violet to near infra-red and the better of luminescence ability than the pristine conducting polymers. The remarkable improvements in photoluminescences of the blends provide useful information to the application of this material in fabrication of optical – electronic devices.  

scholarly journals The mechanics of the water molecule

1912 ◽  
Vol 86 (584) ◽  
pp. 102-105
Keyword(s):  
Dielectric Constant ◽  
Water Molecule ◽  
Water Vapour ◽  
Visible Spectrum ◽  
Ultra Violet ◽  
Hydrogen Atoms ◽  
Infra Red ◽  
Before And After

In the ultra-violet and visible spectrum water is very transparent. In the infra-red it absorbs very strongly. E. Aschkinass has investigated its absorption in the infra-red, and has represented his results in tables, giving a constant ε in terms of λ, ε being defined by the equation I = I 0 e -ε d where I 0 and I are the intensities before and after traversing a layer d cm. thick. I have calculated ε into the more useful constant k , ( v - i k ) 2 being the dielectric constant, and have plotted the result in the following curve. The two constants ε and k are connected by the relation ελ = 4π k . From the curve it is evident that water has two great maxima at 3.07 μ and 6.15 μ respectively. These occur also in water vapour; they do not occur in oxygen or hydrogen. It seems therefore plausible to connect them with the linkings of the oxygen and hydrogen atoms. A system of three atoms should, of course, have two periods.

scholarly journals Effect of infra‐red power level on the sintering behaviour in the high speed sintering process

2008 ◽  
Vol 14 (3) ◽  
pp. 155-160 ◽  
Author(s):  
C.E. Majewski ◽  
D. Oduye ◽  
H.R. Thomas ◽  
N. Hopkinson
Keyword(s):  
Optical Microscopy ◽  
Layer Thickness ◽  
High Speed ◽  
Power Level ◽  
Single Layer ◽  
Content Type ◽  
Red Power ◽  
Infra Red ◽  
Sintering Characteristics ◽  
Sintering Behaviour

PurposeTo investigate the effects of the infra‐red power level on sintering behaviour in the high speed sintering (HSS) process.Design/methodology/approachSingle‐layer parts were produced using the HSS process, in order to determine the effect of the infra‐red power level on the maximum achievable layer thickness, and the degree of sintering. The parts were examined using both optical microscopy and contact methods.FindingsIt was initially expected that an increase in the infra‐red lamp powder might allow an increase in the depth of sintering that could be achieved, as a result of increased thermal transfer through the powder. However, results in fact indicated that there is a maximum layer thickness that can be achieved, as a result of part shrinkage in the z direction. Optical microscopy images have shown that a greater degree of sintering occurs at higher power levels, which would be expected to correspond to an improvement in the mechanical properties of the parts produced. These images also indicate that the radiation absorbing material forms in small “islands” on the powder bed surface. As sintering progresses, these islands begin to merge; this occurs to a greater extent at higher infra‐red lamp powers.Research limitations/implicationsThese results are based only on single layer parts. Further work will examine the sintering characteristics of multiple layer parts.Practical implicationsResults have shown that, whilst it is not possible to increase the achievable layer thickness of the parts produced by modifying the infra‐red lamp power, the degree of sintering can be improved greatly by increasing the power.Originality/valueHSS is an entirely new process which is currently still under development; the results presented here will directly impact the direction of further development and research into this process.

XXXVII.—The Absorption of Light by Inorganic Salts. No. II.: Aqueous Solutions of Cobalt Salts in the Visible Spectrum

1912 ◽  
Vol 31 ◽  
pp. 530-537 ◽  
Author(s):  
R. A. Houstoun ◽  
Alex. R. Brown
Keyword(s):  
Aqueous Solutions ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Sulphate Chloride ◽  
Absorption Of Light ◽  
Infra Red

As in the case of the work in the infra-red, the salts experimented on were the nitrate, sulphate, chloride, bromide, fluoride, and iodide, and they were obtained from Kahlbaum. Very little trouble was experienced with the sulphate, nitrate, and chloride. The salts were supplied as CoSo47H2O, Co(NO3)26H2O, CoCl26H2O. The fluoride was a pinkish powder sparingly soluble in water. It dissolved with formation of insoluble oxyfluoride which seemed to increase on standing. By heating the salt and driving off the water of crystallisation, it was found to be Cof22H2O. The iodide was an extremely deliquescent green powder. A slight insoluble chocolate-coloured residue remained in the solution and was filtered off. By heating the salt it was found to have the composition CoI2H2O. The bromide consisted of very deliquescent crimson lumps, and was found to have the composition CoBr26H2O.

The identification of sulphide minerals by infra-red spectroscopy

1978 ◽  
Vol 42 (322) ◽  
pp. 277-277 ◽  
Author(s):  
R. Soong ◽  
V. C. Farmer
Keyword(s):  
Fourier Transform ◽  
Total Absorption ◽  
Absorption Bands ◽  
Broad Absorption ◽  
Metallic Conductivity ◽  
Sulphide Minerals ◽  
Infra Red ◽  
Vibrational Features ◽  
Red Radiation ◽  
Common Sequence

SynopsesThe value of infra-red spectra in identifying sulphide minerals has been assessed by surveying the spectra of some forty specimens. Spectra of finely ground samples dispersed in polyethylene discs were obtained in the region 420-90 cm−1 with a resolution of 3–4 cm−1, using a Beckman-RIIC Fourier-Transform Interferometer. Except for minerals whose metallic conductivity obliterated vibrational features, the spectra permitted rapid recognition of sulphide minerals either alone or in mixtures.Spectra of the following twenty-five pure, or nearly pure specimens are presented: cinnabar, galena, pyrrhotine, alabandine, sphalerite, wurtzite, realgar, orpiment, stibnite, bismuthinite, arsenopyrite, tetrahedrite, pyrargyrite, proustite, enargite, bournonite, boulangerite, jamesonite, and plagionite. Sulphides whose metallic conductivity led to featureless, almost total, absorption of infra-red radiation included chalcosine, troilite, millerite, covelline, bornite, and pyrrhotine: only the spectrum of the last is illustrated as a typical example.Comparison of the spectra reproduced here with those previously published show a fair measure of agreement, although there are discrepancies. Povarennykh and co-workers, for example, have reported a common sequence of broad absorption bands at 370, 280, and 180 cm−1 for minerals that were found here to exhibit featureless metal-like absorption. The sources of these and other discrepancies are briefly discussed.

XXXVIII.—The Absorption of Light by Inorganic Salts. No. III.: Aqueous Solutions of Nickel Salts in the Visible Spectrum and the Infra-Red

1912 ◽  
Vol 31 ◽  
pp. 538-546 ◽  
Author(s):  
R. A. Houstoun
Keyword(s):  
Aqueous Solutions ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Cotton Wool ◽  
Absorption Of Light ◽  
Infra Red

The methods and the apparatus were the same as in the two previous articles of the series and hence need not be described, the only change being in connection with the galvanometer. Previously it had rested on the table, but when half the results in the infra-red recorded in this paper were obtained, the arrangement was changed; it was suspended by three iron wires each about one and a half metres long from a bracket in the wall and hung with its three levelling screws clearing the table by about one centimetre. Between the table and levelling screws were placed loose wads of cotton wool for the purpose of damping any vibrations that might arise. With this arrangement the zero is very much less sensitive to vibration. With the lamp and scale at one and a half metres—the distance at which they are ordinarily used now–vibrations of the laboratory rarely cause the zero to move mm. either way.

Lie Algebraic Study of Infra-Red Active Spectra of Single-Layer Graphene

2014 ◽  
Vol 34 (3) ◽  
pp. 214-224
Author(s):  
Ratan Das ◽  
Rupam Sen ◽  
Ashim Kalyan ◽  
Raghunandan Das ◽  
Subha Gaurab Roy ◽  
...  
Keyword(s):  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Infra Red

The termination of the afferent nerve fibre in the muscle spindle of the frog

1961 ◽  
Vol 243 (703) ◽  
pp. 221-240 ◽  
Keyword(s):  
Connective Tissue ◽  
Muscle Spindle ◽  
Sensory Nerve ◽  
Nerve Endings ◽  
Muscle Fibres ◽  
Intrafusal Muscle ◽  
Sensory Nerve Endings ◽  
Intrafusal Fibres ◽  
Reticular Zone ◽  
Sensory Endings

1. The sensory nerve contacts in the muscle spindle of the frog were examined in the electron microscope. 2. The terminal branches of the sensory axon form long beaded chains, i.e. bulbous expansions up to 2 to 3 ix thick connected in series by thin cylinders of as little as 0.15 ju. diameter. Many nerve bulbs are seated in cup-like depressions of the intrafusal muscle fibres forming close contact with them. There is a residual gap between nerve and muscle surfaces of about 150 Å, but the gap is bridged here and there by fine filaments or processes of one cell closely approaching or touching the other. 3. The region of sensory contacts along the intrafusal fibres extends over several hundred microns and is divided into two morphologically distinct types of zones: ( a ) two ‘compact’ zones at either end, each about 300 /u. long, in which the fibre retains approximately the same size and number of myofilaments as in the remote, extracapsular, region; ( b ) a ‘reticular’ zone in the centre, about 100 /rlong, in which the fibre loses some 85 % of its content of filaments and splays out into several fins and branches held together by slender membrane connexions. The interstices between the splayed-out parts are filled with a dense network of fine connective tissue fibrils (about 50 Å thick). A minority of the intrafusal fibres does not show this differentiation in the sensory region and retains most of its myofilaments throughout. 4. Several characteristic differences are described between motor and sensory nerve endings on intrafusal muscle fibres. Among them are ( a ) that the motor terminal forms an ‘epectolemmal’, the sensory ending a ‘ hypectolemmaP contact (referring to the external basement membrane of the cells as the ‘ectolemma’) ; ( b ) the motor ending remains invested by a covering Schwann cell layer, while the sensory endings are not closely associated with satellite cells; ( c ) the cytoplasm of motor endings is characterized by an accumulation of 500 Å vesicles near the synaptic surface, that of sensory endings by an accumulation of small mitochondria. 5. A structure of unusual periodicity (a longitudinal ‘micro-ladder with rungs about 1600 Å apart) was observed in the interior of intrafusal muscle fibres, located generally in the neighbourhood of sensory nerve contacts. 6. The functional significance of some of the observed morphological features is discussed. It is suggested that mechanical stimulation and depolarization of the sensory nerve endings occurs at the points of adhesion between the intrafusal muscle fibre and the terminal nerve bulbs. The differentiation between ‘dynamic’ and ‘static’ components of the sensory stretch response may arise from different visco-elastic properties of the ‘compact’ and ‘reticular’ zones. Motor activation of the intrafusal muscle fibres would lead to intense stimulation of the sensory endings mainly within the ‘reticular’ zone. This zone is protected against overstretching by a feltwork of connective tissue fibrils.

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