bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Bone Mineral in vivo: An Improved Method
Authors: Cameron John R. , Sorenson James
Published: October 2006

The mineral content of bone can be determined by measuring the absorption by bone of a monochromatic, low-energy photon beam which originates in a radioactive source (iodine-125 at 27.3 kev or americium-241 at 59.6 kev). The intensity of the beam transmitted by the bone is measured by counting with a scintillation detector. Since the photon source and detector are well collimated, errors resulting from scattered radiation are reduced. From measurements of the intensity of the transmitted beam, made at intervals across the bone, the total mineral content of the bone can be determined. The results are accurate and reproducible to within about 3 percent.
Alcohol Consumption in Rats: Effects of Intracranial Injections of Ethanol
Authors: Myers Robert D.
Published: October 2006

After permanent implantation of intraventricular cannulae, rats were repeatedly infused with ethanol solutions of several concentrations. Pronounced preferences were exhibited for ordinarily noxious ethanol without prior oral exposure to this fluid. Since preferences for ethanol remained unusually high after cessation of infusion, a permanent change may take place in the central nervous system.
Plague Toxin: Its Effect in vitro and in vivo
Authors: Rust James H. , Cavanaugh Dan C. , Kadis Solomon , Ajl Samuel J.
Published: October 2006

The murine toxin of
Pasteurella pestis
inhibited the respiration of heart mitochondria from the rat and the mouse but had little or no effect on the respiration of mitochondria from the rabbit, chimpanzee, dog, and monkey. Alterations occurred in the S-T segments of the electrocardiograms recorded from rats injected with ¼; to 10 LD
50
of toxin, but not in those from rats dying of hemorrhagic shock, hypoxia, intoxication with glucose, or Escherichia coli endotoxin. No abnormalities were observed in electrocardiograms from rabbits injected with large amounts of toxin.
Thermoperiodism in Sea-Run Cutthroat Trout (
Salmo clarki clarki
)
Authors: Heath Wallace G.
Published: October 2006

Thermal tolerances from square-wave cycled temperature acclimation were compared with those from constant acclimation temperatures. A response to the maximum temperature of the square-wave cycle occurred. The acclimation thermoperiod was varied from one-fourth to twice the 24-hour cycle, and a relative maximum of tolerance resulted for the 24-hour thermoperiod. This suggests physiological adaption to natural 24-hour thermoperiods.
Sodium Perxenate Hexahydrate
Authors: Zalkin Allan , Forrester J. D. , Templeton David H. , Williamson Stanley M. , Koch Charles W.
Published: October 2006

Sodium perxenate hexahydrate (Na
4
XeO
6
⋅6H
2
O) has been identified from study of its crystal structure by x-ray diffraction. The perxenate ion (XeO
6
-4
) has the shape of a regular octahedron with the Xe-O bond distance 1.84 Å.
Long-Term Isolation Stress in Rats
Authors: Hatch Anita , Wiberg G. S. , Balazs Tibor , Grice H. C.
Published: October 2006

Rats isolated for long periods became nervous and aggressive and developed caudal dermatitis (scaly tail). After 13 weeks of isolation, rats had heavier adrenals and thyroid and lighter spleen and thymus compared with rats kept in community cages. This indicates an endocrinopathy with hyperfunction of the adrenal cortex.
Late Twilight Glow of the Ash Stratum from the Eruption of Agung Volcano
Authors: Meinel Marjorie Pettit , Meinel Aden B.
Published: October 2006

Observation of the height of the dust layer responsible for the onset of brilliant sunsets in the 30°N zone since September 1963 gives evidence that the ash has diffused from the eruption of the volcano Agung on Bali. A height of 22 km is derived for the top of the primary stratum.
Thermochemical Properties of Xenon Difluoride and Xenon Tetrafluoride from Mass Spectra
Authors: Svec Harry J. , Flesch Gerald D.
Published: October 2006

The standard heats of formation for gaseous xenon tetrafluoride and xenon difluoride and the average strength of the bonds in these molecules have been determined from appearance-potential data obtained with a mass spectrometer. The experimental values are compatible with theoretical estimates of these quantities.
Sharks: Attraction by Low-Frequency Sounds
Authors: Nelson Donald R. , Gruber Samuel H.
Published: October 2006

Large sharks (Carcharhinidae, Sphyrnidae), in their natural environment, were attracted to low-frequency (predominantly 20 to 60 cy/sec) pulsed sounds, but apparently not to higher frequency (400 to 600 cy/sec) pulsed sounds, or to low-frequency continuous sounds. The sharks apparently detected and oriented to the sounds in the acoustic far field.
Bipolar Planarians in a Stock Culture
Authors: Jenkins Marie M.
Published: October 2006

Four long bipolar planarians were discovered in a stock culture of asexual
Dugesia dorotocephala
. Such worms have not been previously reported. Eyespots, auricles, and responses to stimuli were normal in each head-end, and functional pharynges were present. Worms in the stock culture had not been subjected to temperature variations, chemicals, or other experimentation. It is suggested that the axial gradient was effectively flattened by a normal head-inhibiting factor being unable to diffuse to the posterior end.
Phosphate Glass Electrode with Good Selectivity for Alkaline-Earth Cations
Authors: Truesdell A. H. , Pommer A. M.
Published: October 2006

A phosphate glass has been found to have a significant electrode specificity toward alkaline-earth ions. The order of selectivity is 2H
+
> Ba
++
> Sr
++
> Ca
++
> 2K
+
> 2Na
+
> Mg
++
. Exchange properties are discussed in relation to possible structure. Its use to determine activity of Ca
++
in natural systems containing Mg
++
is suggested.
Heparin Bonding on Colloidal Graphite Surfaces
Authors: Gott Vincent L. , Whiffen James D. , Dutton Robert C.
Published: October 2006

Experiments on clotting, both in vitro and in vivo, showed that a colloidal graphite surface, when rinsed with a cationic, surface-active agent, was capable of bonding heparin. The resistance of this graphite-heparin surface to the formation of clots was far greater than plastic or silicone surfaces in comparable studies.
Genetics and Intelligence: A Review
Authors: Erlenmeyer-Kimling L. , Jarvik Lissy F.
Published: October 2006

A survey of the literature of the past 50 years reveals remarkable consistency in the accumulated data relating mental functioning to genetic potentials. Intragroup resemblance in intellectual abilities increases in proportion to the degree of genetic relationship.
Abscisin II, an Abscission-Accelerating Substance from Young Cotton Fruit
Authors: Ohkuma K. , Lyon J. L. , Addicott F. T. , Smith O. E.
Published: October 2006

Crystalline abscisin II, with a tentative molecular formula of C
15
H
20
O
4
, has been isolated from young cotton fruit. It accelerates abscission when applied in amounts as low as 0.01 μg per abscission zone. It inhibits indoleacetic acid-induced straight growth of Avena coleoptiles but has no gibberellin activity on dwarf maize.
Oncogenic Effect of Human Adenovirus Type 12, in Mice
Authors: Yabe Yoshiro , Samper Luis , Bryan Estelle , Taylor Grant , Trentin John J.
Published: October 2006

Undifferentiated malignant tumors were induced at the site of injection of human adenovirus type 12 into newborn mice of the C
3
H
f
/ G
8
strain, but not of the DBA
f
or A
f
strains. The tumors were grossly and histologically similar to those induced by this virus in hamsters, but appeared in a smaller percentage of injected mice than hamsters.
Cholinesterase Inhibition in Spider Mites Susceptible and Resistant to Organophosphate
Authors: Smissaert H. R.
Published: October 2006

Evidence is provided that organophosphate resistance in a strain of spider mites is due to decreased sensitivity of its cholinesterase to organophosphates. The cholinesterase activity of the susceptible strain in vitro was three times that of the resistant strain of mites.
Novel Filter for Biological Materials
Authors: Fleischer R. L. , Price P. B. , Symes E. M.
Published: October 2006

Thin plastic sieves with precisely controlled hole size and density can be made by irradiating plastic films with fission fragments and etching out the material traversed by the fragments. These filters may be used for the nondestructive separation of cells of closely similar sizes.
Diglyceride Release from Insect Fat Body: A Possible Means of Lipid Transport
Authors: Chino Haruo , Gilbert Lawrence I.
Published: October 2006

Lipid is released in the form of diglyceride from the fat body of the cecropia silkmoth (
Hyalophora cecropia
), in both adults and pupae. This diglyceride, in the form of a complex with hemolymph protein, is the most probable means by which lipid is transported in this insect.
Negative Temperature Coefficient of Resistance in Bismuth I
Authors: Souers P. C. , Jura G.
Published: October 2006

Measurements of the electrical resistance have been made on bismuth 1 between 15 and 35 kilobars at temperatures between 77.4° and 120°K. Above about 150°K, the temperature coefficient of resistance is positive, as in a metal; below 150°K, the coefficient becomes negative, as is characteristic of semiconductors. On the basis that bismuth is a semiconductor, the energy gap, calculated by the exponential resistance formula, is 0.006 ev at 15 kb with a steady rise to 0.018 ev at 35 kb. At higher pressures, bismuth I is transformed into a metallic modification with the normal temperature dependence of the resistance. The energy gap in bismuth I is not visible at room temperature because thermal excitation populates the conduction band and metallic behavior is the result. From available evidence the observed behavior is due to an energy gap rather than to a decrease in carrier mobility.
Pteridines as Pigments in Amphibians
Authors: Obika Masataka , Bagnara Joseph T.
Published: October 2006

Extracts of brightly colored skins from nine amphibian species were analyzed chromatographically. In yellow skin in which xanthophores predominated, relatively large quantities of sepiapterin were found, while in red skin which was laden with erythrophores, three drosopterins were most prevalent. Frozen sections of skin indicated that pteridines were present within chromatophores, either alone or accompanied by carotenoids. It is concluded that sepiapterin and three drosopterins are utilized as pigments in amphibians and it is suggested that other less brightly colored pteridines also function in this respect. It no longer seems proper to make the tacit assumption that bright pigmentation of amphibians is due only to the presence of carotenoids.
Neuraminidases and Influenza Virus Infection in Embryonated Eggs
Authors: Johnson Clarence A. , Pekas Darold J. , Winzler Richard J.
Published: October 2006

Highly purified neuraminidase from influenza virus prevents embryonated eggs from infection by Lee-B influenza virus. The degree of prevention afforded is equal to that of neuraminidases from
Vibrio cholerae
and from
Clostridium perfringens
when assayed at the same enzyme activity. The preventive effect is much lower against PR-8 virus. The results support the concept that the intact "receptor" containing sialic acid is required for the binding and infection of cells by influenza viruses.
Visual Pigments of Single Primate Cones
Authors: Marks W. B. , Dobelle W. H. , MacNichol E. F.
Published: October 2006

Single parafoveal cones from human and monkey retinas were examined in a recording microspectrophotometer. Three types of receptors with maximum absorption in the yellow, green, and violet regions of the spectrum were found. Thus the commonly held belief, for which there has previously been no direct and unequivocal evidence, that color vision is mediated by several kinds of receptors (possibly three), each containing photopigments absorbing in different regions of the spectrum, is confirmed.
Excess Lactate: An Index of Reversibility of Shock in Human Patients
Authors: Broder George , Weil Max H.
Published: October 2006

"Excess lactate," an indicator of oxygen debt, has been studied as a metabolic index of severity of the shock state in human patients. The levels of excess lactate correspond to severity of circulatory failure, and an excess of more than 4 millimoles per liter prognosticates a fatal outcome. The validity of this index was confirmed by studies on experimental hemorrhagic shock in dogs. It provides a parameter for measurement of "reversibility" and serves as an objective clinical guide.
Defense of Mate and Mating Chamber in a Wood Roach
Authors: Ritter Hope
Published: October 2006

Studies of the eastern wood roach,
Cryptocercus punctulatus
, reveal that, under laboratory conditions, the mating chambers in rotten wood are inhabited by mated pairs, the male of which will usually defend the chamber successfully against intruding males by a form of fighting. In every staged contest in which the intruder won the fight, it also won the resident female. Females, as well as unmated males singly inhabiting a chamber, could not be induced to defend against an intruder of either sex.
Resonance-Enhanced X-Rays in Thin Films: a Structure Probe for Membranes and Surface Layers
Authors: Wang Jin , Bedzyk Michael J. , Caffrey Martin
Published: October 2006

An x-ray resonance effect in an organic thin film on an x-ray reflecting mirror is reported. The resonance effect is the result of interference between reflected and refracted x-rays at the air-organic thin film interface and occurs at incident angles slightly above the critical angle of the film. In excellent agreement with theory, the primary resonant x-ray electric field that is confined in the organic thin film is ∼20 times as intense as the electric field of the incident beam when measured at a position close to the center of the film. Resonance-enhanced x-rays can be used to characterize the internal structure of Langmuir-Blodgett thin film membranes. This effect may also find use in x-ray-based thin film devices and in the structural analysis of adlayers and surfaces that have thus far proved difficult, if not impossible, to study because of sensitivity limitations.
Homobatrachotoxin in the Genus
Pitohui
: Chemical Defense in Birds?
Authors: Dumbacher John P. , Beehler Bruce M. , Spande Thomas F. , Garraffo H. Martin , Daly John W.
Published: October 2006

Three passerine species in the genus
Pitohui
, endemic to the New Guinea subregion, contain the steroidal alkaloid homobatrachotoxin, apparently as a chemical defense. Toxin concentrations varied among species but were always highest in the skin and feathers. Homobatrachotoxin is a member of a class of compounds collectively called batrachotoxins that were previously considered to be restricted to neotropical poison-dart frogs of the genus
Phyllobates
. The occurrence of homobatrachotoxin in pitohuis suggests that birds and frogs independently evolved this class of alkaloids.
The Annexins and Exocytosis
Authors: Creutz Carl E.
Published: October 2006

The annexins are a group of homologous proteins that bind phospholipids in the presence of calcium. They may provide a major pathway for communication between cellular membranes and their cytoplasmic environment. Annexins have a characteristic "bivalent" activity in the sense that they can draw two membranes together when activated by calcium. This has led to the hypothesis that certain members of this protein family may initiate contact and fusion between a secretory vesicle membrane and the plasma membrane during the process of exocytosis.
Freezing and Viability of
Tetrahymena pyriformis
in Dimethylsulfoxide
Authors: Hwang Shuh-Wei , Davis E. E. , Alexander M. T.
Published: October 2006

Ciliated protozoa may be preserved at very low temperatures.
Tetrahymena pyriformis
, suspended in 10 percent dimethylsulfoxide, survived when frozen in two steps, first to -20°C, then transferring immediately to a temperature of -196°C. Motility and ability to reproduce were recovered after freezing by this method and subsequent storage for 3 months in a liquid nitrogen refrigerator.
Transpiration: Its Effects on Plant Leaf Temperature
Authors: Cook G. D. , Dixon J. R. , Leopold A. C.
Published: October 2006

A definite and significant temperature gradient exists over the area of a tomato leaflet and is apparently due to the variation in transpiration across the leaflet. Transpiration is most effective at low velocities of air movement, but when the velocity increases, convection becomes the dominant factor. Leaves in which the stomata are allowed to open naturally in response to light attain temperatures about 5°C lower than leaves in which the stomata are forced to remain closed.
Induction of a Stereoscopic Depth Effect
Authors: Pastori Nicholas
Published: October 2006

Two pairs of horizontal lines of equal length, with different configurations of dots above and below, are presented stereoscopically. Upon fusion, the two lines are perceived as tilting in space in directions opposite to the depth effects of the dots.
Pressure Distribution Measurements in Fixed-Anvil High-Pressure Cells
Authors: Lippincott Ellis R. , Duecker Heyman C.
Published: October 2006

Absorption spectra of selected microsections of materials with pressure-sensitive absorption bands mounted in diamond-anvil high-pressure cells were determined. The shift in the absorption peak, combined with data obtained at uniform pressure, permits calculation of the pressure of the microsection selected. Examples of a parabolic decrease in pressure from the center to the edge of the diamond anvil are demonstrated by contour diagrams.
Taste Sensitivity to Phenylthiourea in Glaucoma
Authors: Becker Bernard , Morton W. Ross
Published: October 2006

In a series of Caucasian patients over the age of 40 years, the number of individuals unable to recognize the bitter taste of phenylthiourea (8.1 mg/100 ml) was found to be 28 percent in a "normal" eye clinic population (446 individuals), 17 percent in a series of 155 patients with angle-closure glaucoma, and 53 percent in 211 patients with primary open-angle glaucoma.
Benzo(
a
)pyrene and Other Polynuclear Hydrocarbons in Charcoal-Broiled Meat
Authors: Lijinsky W. , Shubik P.
Published: October 2006

The possible production of carcinogenic polynuclear hydrocarbons in the charcoal broiling of food has been investigated. Fifteen steaks were cooked and the polynuclear compounds were extracted, separated by chromatography, and identified spectrometrically. Many polynuclear hydrocarbons were identified, but no nitrogen heterocyclic compounds were detected. The carcinogen benzo(a)pyrene was present in the average amount of 8 micrograms per kilogram of steak.
Alaskan Earthquake of 27 March 1964: Remote Seiche Stimulation
Authors: Donn William L.
Published: October 2006

After the intense Alaskan earthquake of 27 March 1964, unusual waves up to 6 feet (about 2 meters) in height occurred at about the time of arrival of seismic waves at many localities along the coasts of Louisiana and Texas. The parameters of local channels at the tide gauge in Freeport, Texas (the only instrument to record significant waves) yield seiche periods close to those of the seismic surface waves suggesting that the water waves were generated by and in resonance with the seismic waves.
Accuracy of Bone Mineral Measurement
Authors: Mazess Richard B. , Cameron John R. , O'Connor Richard , Knutzen David
Published: October 2006

The use of nearly monochromatic radiation (I
125
) for the direct determination of bone mineral absorption in cadaver materials indicates that underlying bone components can be measured accurately on the flesh-covered forearm. The correlation of the bone mass, determined by this scanning technique, with actual bone weight is 0.96. The method is the most accurate yet demonstrated for bone with overlying tissue, and may prove suitable for these studies in vivo where it has not been possible to use previous roentgenologic techniques.
Neutral Salts: The Generality of Their Effects on the Stability of Macromolecular Conformations
Authors: von Hippel Peter H. , Wong Kwok-Ying
Published: October 2006

The effects of various neutral salts on the temperature of the thermally-induced denaturation of the globular protein ribonuclease are described and compared with the effects of these salts on helix-coil transition temperatures in other macromolecules. These agents affect the stability of the native form of macromolecules as diverse as ribonuclease, collagen, DNA, and myosin in very similar ways; salts such as KSCN and CaCl
2
serve as very potent general structural destabilizers or denaturants, while salts such as (NH
4
)
2
SO
4
and K
2
HPO
4
strongly stabilize the native conformation. The effectiveness of the neutral salts as ribonuclease destabilizers is compared with that of urea and the guanidinium salts.
RNA Codewords and Protein Synthesis
Authors: Nirenberg Marshall , Leder Philip
Published: October 2006

A rapid, sensitive method is described for measuring C
14
-aminoacyl-sRNA interactions with ribosomes which are specifically induced by the appropriate RNA codewords prior to peptide-bond formation. Properties of the codeword recognition process and the minimum oligonucleotide chain length required to induce such interactions are presented. The trinucleotides, pUpUpU, pApApA, and pCpCpC, but not dinucleotides, specifically direct the binding to ribosomes of phenylalanine-, lysine-, and proline-sRNA, respectively.

Since 5′-terminal, 3′-terminal, and internal codewords differ in chemical structure, three corresponding classes of codewords are proposed. The recognition of each class in this system is described. The template efficiency of trinucleotide codewords is modified greatly by terminal phosphate. Triplets with 5′-terminal phosphate are more active as templates than triplets without terminal phosphate. Triplets with 3′- or 3′ (2′)-terminal phosphate are markedly less active as templates. These findings are discussed in relation to the probable functions of terminal codewords. The modification of RNA and DNA codewords, converting sense into missense or nonsense codewords, is suggested as a possible regulatory mechanism in protein synthesis.
Activation of a Plant Gene by T-DNA Tagging: Auxin-Independent Growth in Vitro
Authors: Hayashi Hiroaki , Czaja Inge , Lubenow Helge , Schell Jeff , Walden Richard
Published: October 2006

A transferred DNA (T-DNA) tagging vector with the potential to produce dominant mutations was used with cocultured
Agrobacterium tumefaciens
and protoplasts to tag genes involved in the action of the plant growth substance auxin. Transgenic calli were selected for their ability to grow in the absence of auxin in the culture media. From one experiment, 12 calli that displayed this phenotype were recovered, of which 11 were able to regenerate into plants. In one plant studied in detail, protoplast division in the absence of auxin genetically cosegregated with a single T-DNA insert. A messenger RNA encoded by a 6.4-kilobase sequence of plant genomic DNA rescued from the mutant is overexpressed relative to untransformed plants. The genomic DNA, as well as a cognate complementary DNA, once transfected into protoplasts promote growth and cell division in vitro in the absence of exogenously added auxin.
Nystagmus as a Criterion of Hypnotically Induced Visual Hallucinations
Authors: Brady John Paul , Levitt Eugene E.
Published: October 2006

Hypnotized subjects who report hallucinating a visual situation which would ordinarily elicit optokinetic nystagmus demonstrate nystagmus under these conditions. They and control subjects are unable to feign nystagmus in the waking state, either by imagining the situation or by direct efforts to simulate the eye movements. Thus an objective criterion is provided for the presence of visual hallucinations.
Digital Computers in the Biological Laboratory
Authors: Schoenfeld Robert L. , Milkman Norman
Published: October 2006

The use of digital techniques in the biological laboratory is relatively recent. At present, computer equipment is extremely expensive by contrast with conventional electronic equipment. However, the costs are decreasing, and these techniques are rapidly becoming more accessible as well as more powerful. Improvement in the fabrication, size, and compactness of solid-state devices promises rapid progress in computer technology of interest to the biologist. Through the use of integrated circuits it will be possible to make general-purpose computers no larger than a laboratory oscilloscope, as compared with the present desk-size console with auxiliary cabinets. Within a decade the speed of computation will increase by an order of magnitude, and the costs will decrease significantly. Moreover, it seems likely that the parts of a computer and the laboratory "interface" will become available as modular units. An experimenter will then be able to assemble the components necessary for a particular application and change them as required. At present, one has to modify commercial equipment for the nonstandard, biological uses. However, with modular building blocks of relatively small size and more reasonable cost the digital computer may become as familiar a laboratory tool tomorrow as the cathode-ray oscilloscope or the spectrophotometer is today.
Protein Purification by Elution Convection Electrophoresis
Authors: Raymond Samuel
Published: October 2006

Purified protein components can be recovered from high-resolution gel-electrophoresis patterns by elution-convection electrophoresis. The protein components are all simultaneously eluted from the gel pattern by horizontal electrophoresis and are then simultaneously concentrated by electro-convection to recover the proteins in nearly the original sample concentration. Thirty individual protein fractions can be recovered in 3 hours from a sample containing 200 milligrams of protein.
Fructose-1,6-diphosphate Requirement of Streptococcal Lactic Dehydrogenases
Authors: Wolin Meyer J.
Published: October 2006

The lactic dehydrogenase of a strain of
Streptococcus bovis
specifically requires fructose-1,6-diphosphate for activity. Phosphate or fructose-1,6-diphosphate prevents inactivation of the dehydrogenase, but phosphate and other compounds cannot be substituted for the fructose-1,6-diphosphate required for activity. Lactic dehydrogenases of other species of
Streptococcus
show a similar requirement for fructose-1,6-diphosphate.
Orgueil Meteorite: Organic Nitrogen Contents
Authors: Hayatsu Ryoichi
Published: October 2006

Purines, amino derivatives of
sym
-triazine, and substituted guanidines isolated from the Orgueil meteorite were identified by chromatographic, spectroscopic, and other techniques. The presence of large amounts of
sym
-triazine derivatives is of particular interest, because these compounds have no known biochemical significance.
Thermoregulatory and Adaptive Behavior of Brown Adipose Tissue
Authors: Smith Robert E.
Published: October 2006

Brown adipose tissue has been shown to be a strongly thermogenic effector organ in homeothermic animals exposed to cold and in hibernators during cold-induced arousal from deep hibernation. Because of the anatomical distribution of brown fat and the utilization of vascular countercurrent heat exchange, this cold-induced thermogenic response protects the animal by contributing heat to the vital organs of the thorax, the cervical and thoracic segments of the spinal cord, and the sympathetic chain. Evidence indicates that control of thermogenic activity of brown fat is mediated by the sympathetic nervous system.
Identification of a Second Pseudoautosomal Region Near the Xq and Yq Telomeres
Authors: Freije Diha , Helms Cynthia , Watson Michael S. , Donis-Keller Helen
Published: October 2006

The telomeres of Xq and Yq have been observed to associate during meiosis, and in rare cases a short synaptonemal complex is present. Molecular cloning of loci from Xqter and Yqter has revealed that their sequence homology extends over 400 kilobases, which suggests the possibility of genetic exchange. This hypothesis was tested by the development of two highly informative microsatellite markers from yeast artificial chromosome clones that carried Xqter sequences and the following of their inheritance in a set of reference pedigrees from the Centre d'Etude du Polymorphisme Humain in Paris, France. From a total of 195 informative male meioses, four recombination events between these loci were observed. In three cases, paternal X alleles were inherited by male offspring, and in one case a female offspring inherited her father's Y allele. These data support the existence of genetic exchange at Xq-Yq, which defines a second pseudoautosomal region between the sex chromosomes.
Stishovite: Synthesis by Shock Wave
Authors: De Carli Paul S. , Milton Daniel J.
Published: October 2006

Small amounts of stishovite were separated from specimens of explosively shocked sandstones, novaculite, and single-crystal quartz. Estimated peak pressures for the syntheses ranged from 150 to 280 kilobars, and shock temperatures were from 150° to 900°C. No coesite was detected in any sample. It is suggested that quartz can invert during shock to a short-range-order phase, with sixfold coordination. A small portion of this phase may develop the long-range order of stishovite, and, during the more protracted decrease of the pressure pulse through the stability field of coesite accompanying meteorite crater formation, a portion may invert to coesite.
Permeability of Insect Cuticle to Water and Lipids
Authors: Locke Michael
Published: October 2006

Insect cuticle presents a paradox: permeability to water may vary at different times, while lipids penetrate readily. Electron microscopy shows that the epicuticle is penetrated by filaments of wax 60 to 130 Å in diameter. These are believed to be lipid-water liquid crystals in the middle phase. The variable permeability to water, and other properties of the cuticle, may be due to phase changes.
Spandex Elastic Fibers
Authors: Hicks Elija M. , Ultee Arnoldus J. , Drougas John
Published: October 2006

A family of synthetic elastic fibers, designated spandex fibers, has been developed, providing new degrees of sheerness and effective "power" in elastic fabrics. These fibers have segmented polyurethane structures. They are durable, they are white and accept dye readily, and they can be set by heat. The development of these fibers has led to new textile technology and to new uses for elastic fabrics.
Heparin Enhancement of Factors Stimulating Bone Resorption in Tissue Culture
Authors: Goldhaber Paul
Published: October 2006

The addition of small amounts of a commercial heparin solution, or a synthetic polysaccharide-sulfuric ester similar in structure to heparin, to the medium in which bone tissue is cultured markedly enhances the amount of bone resorption obtained with suboptimal concentrations of parathyroid extract or other factors which stimulate bone resorption. It is suggested that heparin be considered a "cofactor" which stimulates bone resorption and which may play an important role in physiological or pathological resorption.
Absence of Taste-Bud Papillae in Familial Dysautonomia
Authors: Smith Alfred , Farbman Alfred , Dancis Joseph
Published: October 2006

No fungiform papillae could be found on the tongues of 30 patients with familial dysautonomia. In ten of these patients a search for vallate papillae was made, but none were found. Inspection of the tongue may thus be useful for diagnosing this rare disease, even in infants. Absence of these sensory receptors suggests that the multiple sensory deficits found in persons with familial dysautonomia may be related to defects in the peripheral receptors.
Lens Fiber Differentiation and Gamma Crystallins: Immunofluorescent Study of Wolffian Regeneration
Authors: Takata Chinami , Albright J. F. , Yamada Tuneo
Published: October 2006

From the adult lens of
Triturus viridescens
, a fraction of proteins was isolated which corresponds to γ-crystallins of higher vertebrates. Tests by immunoelectrophoresis indicate that the antiserum against this fraction reacts with γ-crystallins, but not with α- or β-crystallins. With this antiserum, an immunofluorescent reagent has been prepared for detection of γ-crystallins from newts. In the normal lens of the adult newt, these crystallins are detected in fiber cells and fiber material, but not in the epithelial cells. During transformation of the iris into the lens after lens removal, the staining reaction is negative in the regenerating tissue up to the time the prospective primary fiber cells begin to elongate. Subsequently, without exception those cells in fiber differentiation indicate a γ-crystallin reaction. When the secondary fiber cells are produced at the equatorial zone of the regenerating lens, they also begin to show a γ-crystallin reaction. Thus, γ-crystallins characterize fiber differentiation.
Peptide Synthesis from Amino Acids in Aqueous Solution
Authors: Ponnamperuma Cyril , Peterson Etta
Published: October 2006

Four dipeptides and a tripeptide were formed when an aqueous solution of glycine and leucine was exposed to ultraviolet light in the presence of cyanamide.
Protective Effects of a Live Attenuated SIV Vaccine with a Deletion in the
nef
Gene
Authors: Daniel Muthiah D. , Kirchhoff Frank , Czajak Susan C. , Sehgal Prabhat K. , Desrosiers Ronald C.
Published: October 2006

Vaccine protection against the human immunodeficiency virus (HIV) and the related simian immunodeficiency virus (SIV) in animal models is proving to be a difficult task. The difficulty is due in large part to the persistent, unrelenting nature of HIV and SIV infection once infection is initiated. SIV with a constructed deletion in the auxiliary gene
nef
replicates poorly in rhesus monkeys and appears to be nonpathogenic in this normally susceptible host. Rhesus monkeys vaccinated with live SIV deleted in
nef
were completely protected against challenge by intravenous inoculation of live, pathogenic SIV. Deletion of
nef
or of multiple genetic elements from HIV may provide the means for creating a safe, effective, live attenuated vaccine to protect against acquired immunodeficiency syndrome (AIDS).
Prevention of Programmed Cell Death in
Caenorhabditis elegans
by Human
bcl-2
Authors: Vaux David L. , Weissman Irving L. , Kim Stuart K.
Published: October 2006

Programmed cell death is a physiological process that eliminates unwanted cells. The
bcl-2
gene regulates programmed cell death in mammalian cells, but the way it functions is not known. Expression of the human
bcl-2
gene in the nematode
Caenorhabditis elegans
reduced the number of programmed cell deaths, suggesting that the mechanism of programmed cell death controlled by
bcl-2
in humans is the same as that in nematodes.
Pyramidal and Non-Pyramidal Pathways in Monkeys: Anatomical and Functional Correlation
Authors: Lawrence Donald G. , Kuypers Henricus G. J. M.
Published: October 2006

In monkeys, corticospinal fibers terminate on motoneurons and interneurons. Brainstem fibers, which may be grouped into medial and lateral pathways, terminate on the same interneurons. Observations following bilateral pyramidotomy indicate that motility can be adequately directed by the brainstem systems while cortical connections add speed and the capacity for further fractionating movements. Further experiments suggest that the medial and lateral brainstem pathways primarily direct proximal and distal movements, respectively.
A New Method for Studying the Atom
Authors: Bashkin Stanley
Published: October 2006

The new spectroscopy is in its infancy, and many fascinating aspects are yet to be studied. The properties of thin films may be studied by means of the excitation they induce in a given kind of beam. The production of ions with but a single electron offers a means of carefully mapping the nuclear charge distribution without the complications introduced by the normal complement of electrons. The study of high-purity, multiply ionized particles should make for better temperature determinations in hot plasmas. Possibly the data on lifetimes and modes of decay of excited energy levels may assist in the quantitative assignment of element abundances in the stars. One can even attempt to use the glowing beams as sources for absorption spectroscopy. The method seems to permit study of every stage of excitation for every stage of ionization for every element in the periodic table. Practical problems may interfere with so complete a study, but a major extension of our knowledge of atomic structure seems to be at hand.
Learning to Read
Authors: Gibson Eleanor J.
Published: October 2006

Reading begins with the child's acquisition of spoken language. Later he learns to differentiate the graphic symbols from one another and to decode these to familiar speech sounds. As he learns the code, he must progressively utilize the structural constraints which are built into it in order to attain the skilled performance which is characterized by processing of higher-order units—the spelling and morphological patterns of the language.
Radiolysis of Thymine in Aqueous Solutions: Change in Site of Attack with Change in
p
H
Authors: Myers L. S. , Ward J. F. , Tsukamoto W. T. , Holmes D. E. , Julca J. R.
Published: October 2006

In the radiolysis of thymine in neutral air-saturated solutions the principal site of attack is at the 5,6 double bond; in strongly alkaline solutions the attack shifts to the 5-methyl group. The shift correlates well with a model based on two changes in the reaction path as the
p
H is increased.
Periodic Compounds: Syntheses at High Pressures and Temperatures
Authors: Hall H. Tracy
Published: October 2006

A new class of compounds, called "periodic compounds," identified by the selection rule
G̅
= σ

d
i
e
i

/σ

d
i

, where
G̅
assumes the integral values 1, 2, 3, . . . corresponding to the periodic table groups I, II, III, . . ., is discussed. The number of bonding electrons contributed by an atom of kind
i
is designated

e
i

, and

d
i

gives the number, per formula weight, of atoms of this kind. Both

e
i

and

d
i

assume integral values. Periodic compounds consist of symmetrical and unsymmetrical types. The recent synthesis of the unsymmetrical periodic compound B
2
O, an isoelectronic analog of carbon, suggests that many more unsymmetrical types may be amenable to synthesis, particularly by high-pressure and high-temperature techniques.
Serotonin: Synthesis and Release from the Myenteric Plexus of the Mouse Intestine
Authors: Gershon Michael D. , Drakontides Anna B. , Ross Leonard L.
Published: October 2006

After injection of its radioactive precursor, 5-hydroxytryptophan, radioactive serotonin was biosynthesized and bound in the myenteric plexus of the mouse intestine. Addition of nonradioactive serotonin to preparations in vitro caused a net release of radioactive serotonin from the plexus. This release appeared to result from activity in the intramural nervous system of the intestine. A neurotransmitter role between sensory and motor neurons in the peristaltic reflex pathway is suggested as a working hypothesis to explain the action of serotonin.
Hypothalamic Lesions by Electrocauterization: Disinhibition of Feeding and Self-Stimulation
Authors: Hoebel Bartley G.
Published: October 2006

Contrary to a recent report, destruction of the medial hypothalamus by electrocauterization with radio-frequency current consistently produced overeating and obesity in rats. This confirms the earlier consensus that destruction in the region of the ventromedial hypothalamus releases feeding from normal inhibition. In addition to augmenting feeding, the same lesions increased the rate of lateral hypothalamic self-stimulation after food satiation had depressed it. Thus the medial hypothalamus, when intact, inhibits both feeding and lateral hypothalamic self-stimulation.
Diffraction and Visual Acuity of Insects
Authors: Palka John
Published: October 2006

Burtt and Catton suggested that insects can resolve striped patterns finer than the theoretical limit set by the small diameter (30 microns) of the ommatidial lenslets. Events at the edges of the window behind which the patterns are moved explain these experiments without transgressing diffraction limitations. This interpretation leads to successful quantitative predictions of the effects of changing the boundary conditions.
Lateral Hypothalamic Stimulation in Satiated Rats: T-Maze Learning for Food
Authors: Mendelson Joseph , Chorover Stephan L.
Published: October 2006

It is well known that electrical stimulation in portions of the lateral hypothalamic area is positively reinforcing and induces eating in satiated rats. We have found that continuous stimulation of this kind can also motivate satiated and previously untrained rats to learn the location of food in a T-maze. Efficient acquisition and reversal of discriminations for food indicate that lateral hypothalamic stimulation exerts motivational effects which are functionally equivalent to those of food deprivation.
Metabolism of Iodine-131-Labeled Thyroxine-Binding Prealbumin in Man
Authors: Oppenheimer Jack H. , Surks Martin I. , Bernstein Gerald , Smith J. Crispin
Published: October 2006

The metabolism of
131
I-labeled thyroxine-binding prealbumin was studied in four normal subjects and in five hospitalized patients with nonthyroidal disease. The average half-time of total-body thyroxine-binding prealbumin, calculated on the basis of a two-compartmental model, was 1.90 days in normal subjects. Increased fractional degradation or diminished synthesis, or both, contributed to the depression of thyroxine-binding prealbumin in the serum of patients with nonthyroidal disorders.
Antarcticite: A New Mineral, Calcium Chloride Hexahydrate, Discovered in Antarctica
Authors: Torii Tetsuya , Ossaka Joyo
Published: October 2006

A new mineral, calcium chloride hexahydrate, was discovered in the Don Juan Pond in Victoria Land, Antarctica. The optical properties, chemical analysis, and powder patterns obtained by x-ray diffraction agree with those of artificial calcium chloride hexahydrate. The name Antarcticite is proposed for the new mineral.
Silicates: Reactivity with Sea Water
Authors: Mackenzie Fred T. , Garrels Robert M.
Published: October 2006

Silicate minerals rapidly release silica to sea water. Fine-grained, 1-gram samples were placed in 200 milliliters of sea water, and the silica content of the water was measured intermittently for 6 months. At the end of 10 days and of 6 months the silica concentrations with various minerals, in parts per million, were, respectively: kaolinite, 0.6, 2.2; chlorite, 2.5, 2.4; illite, 1.8, 2.6; muscovite, 1.8, 3.9; montmorillonite A, 7, 10.5; montmorillonite B, 10, 21. Except for ion exchange phenomena, it generally has been assumed that these minerals do not react significantly with sea water, or, if they do, they react at geologically slow rates. The rates observed indicate that the ocean must be looked upon as a chemical system with a rapid response to added detrital silicates.
Release of Dissolved Amino Acids by Marine Zooplankton
Authors: Johannes R. E. , Webb Kenneth L.
Published: October 2006

Marine net zooplankton release dissolved amino acids into the water. Release rates are positively correlated with temperature and can be estimated by the equation: Release rate, (milligrams of alpha-amino nitrogen per gram dry weight of zooplankton per day) = 1.0 × temperature (°C) —5.9. Release rates appeared to be independent of the taxonomic composition of the test samples, which were variously dominated by copepods, salps, chaetognaths, coelenterates, or radiolarians. These amino acids constitute an important source of dissolved organic matter in the sea.
Messenger RNA in Early Sea-Urchin Embryos: Cytoplasmic Particles
Authors: Spirin Alexander S. , Nemer Martin
Published: October 2006

Three structures containing messenger RNA can be demonstrated in the cytoplasm of early sea-urchin embryos: (i) particles that sediment more slowly than ribosomes and contain newly synthesized DNA-like RNA, (ii) light polyribosomes, which also contain this newly synthesized RNA, and (iii) heavy polyribosomes, which seemingly contain only already existing or "maternal" messenger RNA and account for the bulk of the synthesis of protein.
Systematic Relationships between Carbon and Oxygen Isotopes in Carbonates Deposited by Modern Corals and Algae
Authors: Keith M. L. , Weber J. N.
Published: October 2006

Analyses of organic carbonates from Jamaican coral reefs show a positive correlation between the O
18
: O
16
ratio and the C
13
: C
12
ratio in some taxonomic groups of corals and algae, but essentially no correlation (nearly constant O
18
) in one suborder of reef-building corals. The strontium and magnesium contents apparently are controlled mainly by skeletal mineralogy and show no correlation with carbon or oxygen isotopic composition. The observed positive correlations between C
13
and O
18
content may be due to calcification processes utilizing carbon-oxygen compounds from two isotopically different sources or utilizing selected portions of a wide spectrum of carbon-oxygen compounds in which there is a positive correlation between C
13
: C
12
and O
18
: O
16
ratios. Coral and algal carbonates from Jamaican waters, with an annual temperature range of only about 4°C, exhibit a total δC
13
range of more than 13 per mil and a δO
18
range of more than 4 per mil. The wide isotopic variability resulting from vital effects of calcifying organisms must be taken into account in applying isotopic analysis to the study of sedimentary carbonate rocks which may include reef-derived carbonates.
Collagenase: Effect on the Morphogenesis of Embryonic Salivary Epithelium in vitro
Authors: Grobstein Clifford , Cohen Julia
Published: October 2006

Salivary epithelium in culture, under conditions which promote morphogenetic branching, grows as a simple disc in the presence of collagenase, or is "depatterned" midway in the morphogenetic course by a short exposure to a collagenase.
Protein Synthesis in Rat Liver: Influence of Amino Acids in Diet on Microsomes and Polysomes
Authors: Fleck A. , Shepherd J. , Munro H. N.
Published: October 2006

Rats were killed 1 hour after having been fed by stomach tube with amino acid mixtures that were either nutritionally complete or lacked tryptophan. Microsomes isolated from the livers of animals fed the incomplete mixture showed a reduced capacity to incorporate
14
C-leucine in vitro, and polysomes prepared from the same livers showed an increased proportion of monosomes and disomes. Prior treatment with actinomycin D did not prevent these differences in response to the two amino acid mixtures, an indication that synthesis of messenger RNA may not be involved in the cell mechanism which recognizes differences in amino acid pattern.
Brain Transplantation: Prolonged Survival of. Brain after Carotid-Jugular Interposition
Authors: White Robert J. , Albin Maurice S. , Locke George E. , Davidson Eugene
Published: October 2006

Six isolated canine brains were successfully transplanted for 6 hours to 2 days to the cervical vasculature of dogs. Viability was shown by electrocortical activity and significant uptakes of oxygen and glucose, with production of carbon dioxide. Cerebral blood flows, temperatures, and pressures of the cerebral homograft were continuously monitored by way of an implantable recording module.
Isoprenoid Hydrocarbons in Recent Sediments: Presence of Pristane and Probable Absence of Phytane
Authors: Blumer Max , Snyder W. Dale
Published: October 2006

Pristane (2,6,10,14-tetramethylpentadecane) has been isolated from two recent marine sediments. Unlike their ancient counterparts, these sediments contain no detectable phytane. These two facts suggest a biochemical origin for at least a fraction of the sedimentary pristane and a later, geochemical formation of phytane. Commercial reagent-grade solvents (pentane, isooctane, methanol) contain appreciable quantities of fossil pristane and probably phytane.