bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of K x‐ray hyper‐satellites and KMM radiative Auger effect (RAE) of the elements 19 ≤ Z ≤ 25 by photon excitation
Authors: Raju S. S. , Reddy B. Seetharami , Murti M. V. R. , Mombasawala L.
Published: December 2006

K x‐ray emission spectra were generated by photon excitation to study the Kα hyper‐satellites, KβL1, Kβ5 satellites and KMM RAE structures of the elements 19⩽Z⩽25 using a wavelength dispersive spectrometer with LiF 200 and LiF 220 crystals. The Z‐dependence of the energy shift and relative intensity of these lines with respect to the diagram lines were studied except in the case of KMM RAE constituent peaks, for which only energy shifts were examined. The measured energy shifts and relative intensities are compared with the available theoretical predictions. Three of the constituent peaks in the KMM RAE structure are assigned K‐M1M2 (3P), K‐M1M2 (1P) and K‐M1M1 (1S) transitions. Copyright © 2006 John Wiley & Sons, Ltd.
Strontium incorporates at sites critical for bone mineralization in rats with renal failure
Authors: Oste Line , Verberckmoes Steven C. , Behets Geert J. , Dams Geert , Bervoets An R. , Van Hoof Viviane O. , Bohic Sylvain , Drakopoulos Michael , De Broe Marc E. , D'Haese Patrick C.
Published: December 2006

We previously demonstrated the development of a mineralization defect during strontium administration and its reversibility after withdrawal in rats with chronic renal failure. Recently, strontium ranelate has been introduced as a therapeutic agent for osteoporosis. However, caution has to be taken, as this bone disorder mainly develops in elderly people who may present a moderately decreased renal function. In order to assess the ultra‐structural localization of strontium in bone and thereby to get a better insight into the element's systemic effects on bone, synchrotron‐based x‐ray micro‐fluorescence was applied, which showed that after 2 weeks of strontium loading (2 g l−1in drinking water) in rats with renal failure, concomitant with the development of impaired mineralization, the element was localized mainly at the outer edge of the mineralized bone, while after longer loading periods, a more homogeneous distribution was found. After washout, strontium was found at sites deeper within the trabeculae, while newly deposited low‐strontium‐containing mineral was found at the outer edges. Synchrotron x‐ray micro‐diffraction analysis showed that strontium is incorporated in the apatite crystal lattice through exchange with calcium.

The results show that strontium is initially incorporated in bone at sites of active bone mineralization, close to the osteoid/mineralization front. Most likely, strontium binds to matrix proteins serving as crystal nucleation points and by heteroionic substitution with calcium within the hydroxyapatite crystals, thereby impairing further hydroxyapatite formation. After withdrawal, strontium is released from these sites, by which mineralization is restored and the previously formed strontium‐containing hydroxyapatite is buried under a new layer of mineralized bone. Copyright © 2006 John Wiley & Sons, Ltd.
Value of Laparoscopic Appendectomy in Perforated Appendicitis
Authors: Fukami Yasuyuki , Hasegawa Hiroshi , Sakamoto Eiji , Komatsu Shunichiro , Hiromatsu Takashi
Published: December 2006

Background

The purpose of this clinical study was to evaluate the efficacy of laparoscopic appendectomy in patients with perforated appendicitis.

Methods

This study involved a total of 73 consecutive patients who had undergone appendectomy for perforated appendicitis between January 1999 and December 2004. While 39 patients underwent open appendectomy (OA) during the first 3 years, the remaining 34 patients underwent laparoscopic appendectomy (LA) during the last 3 years.

Results

There was no case of LA converted to OA. No significant difference was found in the operating time between the two groups. Laparoscopic appendectomy was associated with less analgesic use, earlier oral intake restart (LA, 2.6 days; OA, 5.1 days), shorter median hospital stay (LA, 11.7 days; OA, 25.8 days), and lower rate of wound infections (LA, 8.8%; OA, 43.6%).

Conclusions

These results suggest that LA for perforated appendicitis is a safe procedure that may prove to have significant clinical advantages over conventional surgery.
Characteristic properties of cutting fluid additives made from the derivatives of some polymeric nonionic surface‐active agents
Authors: Nakagawa H. , Watanabe S. , Fujita T. , Sakamoto M.
Published: December 2006

A series of esters was prepared from the reaction of acid chlorides with polymeric nonionic surface‐active agents (copolymer of propylene oxide and ethylene oxide), and they were screened for antirust and other properties associated with water‐based cutting fluids. An aqueous emulsion of an adduct of triethanolamine and the oleic acid ester of polymeric nonionic surface‐active agent showed excellent antirust properties when used as a water‐based cutting fluid. The emulsion of triethanolamine and the mono nonyl ether of the surface‐active agent also showed antirust properties.
Neutron activation analysis as a method for measuring soil removal of unsaturated oils and for estimating their degree of aging on fabric
Authors: Choe Eun Kyung , Obendorf S. Kay
Published: December 2006

Neutron activation analysis of bromine‐tagged oils on fabric provides a quantitative method for evaluating the degree of aging of unsaturated oils on fabric as well as a new method for measuring their soil removal by estimating the quantity of double bonds, before and after laundering. When aged at 21°C for 5 wk, 62, 63, and 20% of double bonds remained for oleic acid, triolein, and squalene, respectively. At 40°C, no double bonds were left after aging of oleic acid and triolein, whereas about 8% of the double bonds remained for squalene. A comparison of this method with the radiotracer method for soil removal measurements shows good agreement between the two methods. Proper treatment time for bromine tagging of unsaturated oils on fabric is any time between 90 s and 10 min under the bromination procedure used. The tagging of double bonds by bromine vapor has advantages of the exact one‐to‐one reaction ratio between Br2 and the number of double bonds of unsaturated oleic acid or triolein, as well as a much lower cost than other tagging reagents like OsO4. Because blank unsoiled fabric was shown to take up Br2, fabric swatches of the same size should be used as controls in neutron activation analysis. This method has advantages of its sensitivity to small amounts, use of nonlabeled soil, quantitative measurement, and ease of sample preparation over the chemical measurement of iodine value.
Complex bombs of phreatomagmatic eruptions: Role of agglomeration and welding in vents of the 1886 Rotomahana eruption, Tarawera, New Zealand
Authors: Rosseel Jean‐Baptiste , White J. D. L. , Houghton B. F.
Published: December 2006

Basaltic bombs ejected from a Rotomahana crater during the 1886 Tarawera eruption in New Zealand are of two fundamental types: cored bombs, which have single large fragments, generally of rhyolite wall rock material, as their cores, and “loaded” bombs, which contain abundant small fragments dispersed through the bombs. Similar lithic‐bearing bombs are common products of other, phreatomagmatic eruptions worldwide. Cored bombs originate when a large wall rock fragment is entrained in basaltic melt and then ejected with an adhering skin of basalt. In contrast, loaded bombs are constructed by agglomeration of multiple fragments of basalt, among which smaller rhyolitic wall rock fragments are dispersed. Different styles and rates of bomb “loading” are reflected in the bombs' textures and compositions. These textures provide insight into the nature of fragmentation during the eruption, the processes of recycling that produce multiply ejected clasts versus “recapitulated” ones (those where early formed clasts were reingested in magma and then formed the cores of new bombs), the degree and timescale of interaction of magma with vent walls, and the timescales over which lithic material from the vent walls is incorporated into complex bombs prior to their ejection. Because fragments of rhyolitic pumice are readily refused, their condition constrains estimates of the timing of fragmentation and agglomeration. The presence of nonfused rhyolite pumice within many loaded bombs implies that the processes forming and quenching the bombs cannot have exceeded several seconds. In contrast, other bombs contain patches of compositionally modified basalt with isolated rhyolite‐derived feldspar xenocrysts that indicate complete fusing, melting and assimilation of entrained rhyolitic debris. The bomb population overall indicates that conditions within this Rotomahana vent were thermally and physically heterogeneous and that recycling of debris was ubiquitous, both as recycling of large individual clasts and by fallback and aggregation of material which was reingested in magma before being reejected as new bombs.
A high throughput drug screen based on fluorescence resonance energy transfer (FRET) for anticancer activity of compounds from herbal medicine
Authors: Tian H , Ip L , Luo H , Chang D C , Luo K Q
Published: December 2006

Background and purpose:

We report the development of a very efficient cell‐based high throughput screening (HTS) method, which utilizes a novel bio‐sensor that selectively detects apoptosis based on the fluorescence resonance energy transfer (FRET) technique.

Experimental approach:

We generated a stable HeLa cell line expressing a FRET‐based bio‐sensor protein. When cells undergo apoptosis, they activate a protease called ‘caspase‐3’. Activation of this enzyme will cleave our sensor protein and cause its fluorescence emission to shift from a wavelength of 535 nm (green) to 486 nm (blue). A decrease in the green/blue emission ratio thus gives a direct indication of apoptosis. The sensor cells are grown in 96‐well plates. After addition of different chemical compounds to each well, a fluorescence profile can be measured at various time‐points using a fluorescent plate reader. Compounds that can trigger apoptosis are potential candidates as anti‐cancer drugs.

Key results:

This novel cell‐based HTS method is highly effective in identifying anti‐cancer compounds. It was very sensitive in detecting apoptosis induced by various known anti‐cancer drugs. Further, this system detects apoptosis, but not necrosis, and is thus more useful than the conventional cell viability assays, such as those using MTT. Finally, we used this system to screen compounds, isolated from two plants used in Chinese medicine, and identified several effective compounds for inducing apoptosis.

Conclusions and Implications:

This FRET‐based HTS method is a powerful tool for identifying anti‐cancer compounds and can serve as a highly efficient platform for drug discovery.

British Journal of Pharmacology (2007) 150, 321–334. doi:10.1038/sj.bjp.0706988
Electrical properties of ion conducting molybdate glasses
Authors: Bhattacharya S. , Ghosh A.
Published: December 2006

The electrical conductivity and conductivity relaxation of xAg2O-(1−x)MoO3 glasses have been reported in the frequency range of 10Hz−2MHz and temperature range of 183–413K. The dc conductivity and activation energy for the binary silver molybdate glasses have been compared with those of Ag+ ion conducting binary phosphate, borate, and tellurite glasses. The silver molybdate glasses exhibit the highest conductivity and the lowest activation energy of the glasses formed with other glass formers such as phosphate, borate, and tellurite containing the same modifier Ag+ ions. We have analyzed the ac conductivity using the power law and the electric modulus formalisms. We have observed that the concentration of mobile Ag+ ions is not thermally activated and only 10%–25% of the total Ag+ ions contribute to the dynamic processes and are independent of the Ag2O content. We have observed that the conductivity relaxation is highly nonexponential. The motion of Ag+ ions is decoupled more and more from the viscous motion of the glassy matrix with the increase of Ag2O content in the investigated glass composition.
Internal magnetic field in thin ZnSe epilayers
Authors: Ghosh S. , Stern N. P. , Maertz B. , Awschalom D. D. , Xiang G. , Zhu M. , Samarth N.
Published: December 2006

Strain-induced spin splitting is observed and characterized using pump-probe Kerr rotation spectroscopy in n-ZnSe epilayers grown on GaAs substrates. The spin splitting energies are mapped out as a function of pump-probe separation, applied voltage, and temperature in a series of samples of varying epilayer thicknesses and compressive strain arising from epilayer-substrate lattice mismatch. The strain is independently quantified using photoluminescence and X-ray diffraction measurements. The authors observe that the magnitude of the spin splitting increases with applied voltage and temperature and is highly crystal direction dependent, vanishing along [11¯0].
Ultrashallow (<10nm) p+∕n junction formed by B18H22 cluster ion implantation and excimer laser annealing
Authors: Heo Sungho , Hwang Hyunsang , Cho H. T. , Krull W. A.
Published: December 2006

In order to form an ultrashallow p+∕n junction, incorporation of a top amorphous-silicon (a-Si) layer is necessary so as to avoid channeling and to fully activate the dopant. Conventional ultrashallow junction processes require two-step implantation such as preamorphization by Si+ or Ge+ implantation and ultralow (<0.5keV) energy B+ implantation. In this report, the authors investigate B18H22+ implantation. Due to the heavy mass of cluster ions, one-step ion implantation at 5keV readily forms a 5-nm-thick a-Si layer and an ultrashallow junction without B channeling. By employing excimer laser annealing, the authors have obtained a shallow junction depth (∼9nm) and low Rs (∼830Ω∕◻).
Influence of residual impurity background on the nonradiative recombination processes in high purity InAs∕GaSb superlattice photodiodes
Authors: da Silva E. C. F. , Hoffman D. , Hood A. , Nguyen B. M. , Delaunay P. Y. , Razeghi M.
Published: December 2006

The influence of the impurity background on the recombination processes in type-II InAs∕GaSb superlattice photodiodes with a cutoff wavelength of approximately 4.8μm was investigated by electroluminescence measurements. Using an iterative fitting procedure based on the dependence of the quantum efficiency of the electroluminescence on the injection current, the Auger and Shockley-Read-Hall lifetimes were determined for photodiodes with background concentration below 1015cm−3. The authors determined in which range of the injection current Shockley-Read-Hall or Auger recombination is predominant. At T=300K, the findings indicate that in high quality material with a low background concentration Auger effect becomes the prevalent mechanism even at low applied current.
Photoluminescence of surface InAs quantum dot stacking on multilayer buried quantum dots
Authors: Liang B. L. , Wang Zh. M. , Mazur Yu. I. , Salamo G. J.
Published: December 2006

Coupling between the surface and the buried quantum dots (QDs) is studied by photoluminescence (PL) measurement for a heterostructure with InAs surface QDs sitting above four layers of buried QDs. Temperature and excitation intensity dependences of the PL together with the PL temporal decay behavior reveal fast carrier transfer from the buried QDs to the surface QDs. The PL signals from the surface and buried QDs are shown to be closely correlated with each other and very surface sensitive. These features support the promise this heterostructure holds for sensor devices.
The Synthesis of 4(6)-t-Butylpyrimidines From 4(6)-Halopyrimidines by Using Higher-Order Lithium and Magnesium Organocuprate Reagents
Authors: Evans RF , Savage GP , Gough DA
Published: December 2006

t-Butyllithium and t- butylmagnesium chloride cyanocuprates were used to prepare 4(6)-t- butylpyrimidines from the corresponding 4(6)-halopyrimidines . The highly hindered 2,4,5-tri-t-butyl-6-chloropyrimidine, containing an ortho-di-t-butyl arrangement, was prepared by this method. No alkyl group isomerization was observed but some substrate reduction was detected.
Solvento Complexes of Main Group Metals: The Structure of the Dimethyl-Sulfoxide Adduct of Indium(III) Perchlorate
Authors: Harrowfield JM , Skelton BW , White AH
Published: December 2006

The title compound is readily obtained as a colourless , crystalline solid by recrystallization of hydrated indium perchlorate from dimethyl sulfoxide. The crystals are rhombohedral , space group R3, a 9.911(3)Ǻ, α 73.66(2)?, Z= 1 f.u.;a single-crystal X-ray structure determination at 295 K refined to R 0.039 for 806 'observed' reflections. Unlike many Me2SO complexes, the indium species contains nicely ordered cations , [In(Me2SO)6]3+. Indium lies on a site of 3 symmetry, with In-O 2.140(3)Ǻ and the angle between the oxygens related by the threefold axis being 94.2(1)°. Two independent perchlorate moieties are disordered about sites of 3 and 3 symmetry.
Palladium-Assisted (Z)-(E) Isomerization of Styrenes
Authors: Giles RGF , Son VRL , Sargent MV
Published: December 2006

It is shown that treatment of stereoisomeric mixtures of styrenes with a catalytic amount of bis ( acetonitrile ) dichloropalladium (II) achieves smooth stereoisomerization of the (Z)-isomers to the (E)-isomers.
Gene‐talk and sport‐talk: A view from the radical middle ground
Authors: Sheridan Heather , Pasveer Bernike , Van Hilvoorde Ivo
Published: December 2006

In this paper, we explore and reflect critically on what elite sport may expect or fear from genetic technologies. In particular, we explore the language in which we (where ‘‘we’’ denotes scientists, sports scientists, the media, sports coaches, academics) tend to speak about genetics, elite sport, and the human body – we call this language ‘‘gene‐talk’’ – which imagines the world of elite sport as one in which genes were always dominant in athletic performance. The dominant question here seems to be whether what is thought to be possible ought to be, and can be realized. We unpack the question by asking whether the practices needed for genetics to intervene so powerfully in elite sport exist in the straightforward and uncomplicated manner that the ‘‘gene‐talk’’ literature seems to suggest. We argue that there is a lack of relevant studies to support and analyse the notion of sports performance as an immensely rich and complex practice.We conclude that elite sport may be more complex and heterogeneous than ‘‘gene‐talk’’ has imagined to date.
Acetate Correction for Postabsorption Metabolism Does Not Improve the [13C]Mixed Triacylglycerol Breath Test
Authors: Slater Christine , Preston Tom , Weaver Lawrence T
Published: December 2006

Objective:

The [13C]mixed triacylglycerol (MTG) breath test is a noninvasive measure of fat digestion. After absorption and oxidation, 13C appears in breath CO2. Recovery is no more than 50% in healthy subjects because of sequestration of acetate in intermediary metabolism. The aims of this study were to investigate interindividual variation and postabsorptive metabolism of MTG using oral [1‐13C]acetate and to examine the use of correction factors to account for the “missing” label.

Patients and Methods:

[13C]mixed triacylglycerol and [1‐13C]acetate breath tests were performed on 8 healthy adults, 9 healthy children and 3 children with cystic fibrosis. Breath was sampled for 6 hours on each occasion. The enrichment of 13CO2 in breath was measured by isotope ratio mass spectrometry. Cumulative percentage dose recovered 13CO2 during the MTG test was corrected for label absorbed, but not completely oxidized using the cumulative percentage dose recovered during the acetate test.

Results:

Mean recovery of 13C during the [13C]MTG test with an acetate correction was close to 100% in healthy subjects: 103.1% (SD, 11.6%) in adults and 98.9% (SD, 30.3%) in children, but the wide variance indicated that some of the assumptions governing the use of acetate corrections with oral tracers may not be valid.

Conclusion:

The need to perform 2 tests, variation in physical activity between tests and differences in intermediary metabolism preclude the use of acetate correction factors when using [13C]MTG to assess intraluminal fat digestion, especially in children.
Decreased Coenzyme Q10 Concentration in Plasma of Children with Cystic Fibrosis
Authors: Oudshoorn Johanna H , Lecluse Anne LY , van den Berg Robin , Vaes Wouter HJ , van der Laag Johan , Houwen Roderick HJ
Published: December 2006

Objectives:

Coenzyme Q10 (CoQ10) is an effective lipophilic antioxidant and protects against lipid peroxidation by scavenging radicals. Patients with cystic fibrosis generally have fat malabsorption; thus, we hypothesized that overall plasma CoQ10 concentration in pediatric patients with cystic fibrosis might be diminished. Because these patients have increased oxidative stress due to chronic pulmonary inflammation, we also assumed that the oxidized form of CoQ10 might be relatively increased.

Patients and Methods:

The total plasma CoQ10 levels and the oxidized and reduced form were measured by high‐performance liquid chromatography in 30 children with cystic fibrosis (mean FEV1 % predicted = 88.5% ± 18.7%) and 30 age‐matched controls.

Results:

Total plasma CoQ10 levels were significantly lower in the cystic fibrosis group as compared with the control group (0.87 ± 0.42 μmol/L and 1.35 ± 0.39 μmol/L, respectively; P < 0.001). When correcting for the lower serum cholesterol level in patients with cystic fibrosis, this difference remained significant: the CoQ10/cholesterol ratio (μmol/mol) was 268.8 ± 136.7 and 334.0 ± 102.9 in patients and controls, respectively (P < 0.05). However, the CoQ10 redox status was identical in patients and controls (86.4% ± 7.1% and 85.4% ± 7.3%, respectively).

Conclusions:

We found that the overall plasma CoQ10 concentration is lower in patients with cystic fibrosis, probably because of fat malabsorption. The CoQ10 redox status was not disturbed, indicating that CoQ10 could still be adequately regenerated in this group of patients with cystic fibrosis with mild‐to‐moderate pulmonary disease.
The preparation of oxygen by electrolysis of baryta
Authors: Stoddart Eric M.
Published: December 2006

Morley, in his classical researches, pointed out that various impurities were present in the gases produced by electrolysis of sulphuric acid and potassium hydroxide solutions. Using the latter method, Lord Rayleigh, by addition of a small quantity of baryta, attempted to minimize the amount of hydrocarbons present in the hydrogen as impurity, derived from the carbonate present in the alkali. Baker pointed out that the action of baryta on potassium carbonate is a reversible one, particularly in the presence of such a large excess of potash, and concluded that Rayleigh's precaution might not be particularly effective. Baker recommended the electrolysis of pure barium hydroxide solution, in which barium carbonate is insoluble, and which consequently must give hydrogen tree from hydrocarbons. He also noted that, with the use of pure baryta solution, the oxygen is apparently free from ozone and hydrogen peroxide. It is to be noted that Baker gave no details concerning the shape and material of his electrodes, or of the currents employed in the electrolysis. The method of electrolysing baryta, using nickel electrodes has become a standard method of preparing small quantities of pure oxygen. The present author has employed the apparatus shown in fig. 1 for this purpose during the past few months. The apparatus consists of two vessels, A and B, constructed from 1-inch internal diameter tubing, carrying nickel electrodes, the upper ends of which are welded to platinum wires sealed through the glass, the seals being sufficiently strong to allow currents up to 2 amperes to pass without cracking the glass. The use of nickel is justified owing to its low hydrogen and oxygen over-voltages. The electrodes are constructed from 18 S. W. O. pure nickel wire, 3 feet of which is coiled up as shown. These electrodes have a fairly large surface area—approximately 34 sq cm. The baryta solution was saturated at room temperature and a layer of pure barium hydroxide was allowed to settle on the bottom of the outer jar. The electrolysis was carried out, using a current of 1 ampere, which kept the temperature of the solution at about 60°C. The oxygen was used in experiments, and was found at first to be highly satisfactory.
The ultra-violet absorption spectra of some complex aromatic hydrocarbons-I
Authors: Mayneord William Valentine , Roe Edna, M. F.
Published: December 2006

During earlier work carried out in this Institute on carcinogenic mixtures obtained from coal-tar, a study of the fluorescence spectra of such mixtures gave useful indications of the type of compound present, and subsequently assisted in the separation of one of them, 1 : 2-benzpyrene. Very small quantities of material may often be detected by the study of fluorescence spectra, but the results are as a rule only qualitative. In general, at room temperature, the fluorescence spectra of hydrocarbons in solution consist of diffuse bands, and the total emitted energy is often very small and consequently difficult to measure. Moreover, the absolute amount of radiated energy depends on Ike energy distribution in the incident radiation, and on such experimental details as concentration of solutions, and size and shape of containing vessels. On the other hand, a quantitative measurement of the ultra-violet absorption spectrum of a solution of a pure compound can be made relatively easily, and not only furnishes a method of identification of the substance but serves as a basis for a theoretical treatment of its molecular structure.
The diamagnetic susceptibilities of salts forming ions with inert gas configurations II-The alkaline halides
Authors: Brindley G. W. , Hoare F. E.
Published: December 2006

The data so far published on the diamagnetic susceptibilities of the alkaline halides, measured for the salts in the crystalline state, are very discordant and incomplete, as reference to Table I will show. The aim in carrying out these experiments has been twofold: firstly, to obtain a complete set of values for these salts and secondly to examine more closely than has hitherto been possible how rigorously the susceptibilities of simple crystalline salts are additive. It has already been established that the susceptibilities are approximately additive, but it has not been possible to test this with exactitude because of (
a
) the large discrepancies between the results obtained by previous observers, and (
b
) the lack of data for many crystals. The discrepancies may have arisen to some extent from the different experimental methods, some of which are more accurate than others and some of which may introduce errors peculiar to themselves. We have therefore made a complete re-determination of the susceptibilities of all the alkaline halides, using the same apparatus and method under the same conditions. Since any systematic experi-mental errors will affect all our results to approximately the same extent, we shall be in a stronger position for testing the additivity of the susceptibilities than if we rely partly on our own and partly on other observers’ results. Previous investigators have measured the susceptibilities of some compounds in the crystalline state and others in solution; the latter are of no help in connexion with our problem, for an examination of the available data suggests that solutions have susceptibilities higher by several per cent, than the corresponding crystals. We cannot, therefore, arrive at any certain conclusion by using results obtained partly for crystals and partly for solutions. 2—Method The method previously described has been used to obtain a complete set of values for the susceptibilities of the alkaline halides. Although slight modifications have been made from time to time, the apparatus has remained, in essentials, the same as when used for the measurement of the susceptibilities of the sodium and potassium halides.
Investigations on the combustion of hydrocarbons II-Absorption spectra and chemical properties of intermediates
Authors: Ubbelohde Alfred Rene Jean Paul
Published: December 2006

The investigations recorded here are a development of the work of Egerton and Pidgeon on the absorption spectra of burning hydrocarbons, which had included investigations of the absorption and slow combustion of alcohols up to amyl alcohols, aldehydes up to valeraldehyde, acids up to butyric; amylene, ethylene, ethyl acetate, ethyl hydroperoxide, diethyl, peroxide, and of anti-knocks such as lead tetraethyl, iron carbonyl, butyl iodide, and aniline. The results were compared with the slow combustion of the normal hydrocarbons up to pentane, in the same apparatus. The only intermediates which could be demonstrated spectroscopically in the slow combustion of hydrocarbons were formaldehyde and organic acids, mainly because only these substances have a sufficiently large absorption coefficient to he detectable at the concentrations occurring. In addition, a characteristic hand was discovered at the end of the (pseudo) induction period, in the slow combustion of the higher hydrocarbons, though the molecule responsible for it was not identified, in spite of a considerable search among the ordinary products of slow combustion.
The shape of the continuous
β
-spectrum of thorium C. C'
Authors: Richardson H. O. W. , Leigh-Smith Alice
Published: December 2006

The theories of
β
-decay based on the neutrino hypothesis predict that a considerable proportion of the electrons emitted from a heavy nucleus will have low energies, owing to the Coulomb attraction between the electron and the nucleus. This prediction has been in apparent conflict with most experimental curves (Madgwick 1927; Scott 1935 ), which show the ordinate of the energy distribution falling to zero at the origin or even before it, thus even indicating a low energy end-point below which no
β
-rays are emitted. It is, however, probable that the experimental uncertainties in the methods which have been used are such that no definite conclusion can be drawn from them about the shape of the low energy end of the spectrum. In these methods the source is deposited on a solid mounting and the emitted
β
-particles pass through a window in entering the detecting apparatus, which may be a counter, a cloud chamber or an ionisation chamber. The window stops all
β
-particles below a certain energy, while those which pass through are reduced in energy and considerably scattered. These effects, which are well shown in curves given by Eddy (1928), produce a marked falling off in the observed number of
β
-particles of low energy. The use of a solid mounting for the source introduced opposite effects giving an increased number of slow electrons; for firstly, the fast electrons will eject slow secondary electrons from the solid mounting and, secondly, if the mounting is thick, a considerable reflexion of the primary electrons will occur with varying losses of energy inside the solid, so that the reflected spectrum will contain relatively more low energy rays.
The influence of temperature on the capture of neutrons by various elements
Authors: Michiels J. L. , Saxton J. A.
Published: December 2006

The velocity distribution of neutrons of thermal energies can be changed by passing the neutrons through a layer of paraffin wax about 1 cm. thick, maintained at a different temperature from that of the neutrons entering the layer (Moon and Tillman 1936). When neutrons of an energy corresponding to room temperature (290° K.) are passed through such a wax layer at 90° K., the radioactivity induced in elements by the absorption of these cooled neutrons is greater than if the layer is also at 290° K. For silver a wax layer of about 1 cm. thickness gives the greatest increase, about 35%. The effect was investigated for several elements and varied from about 20% for iodine to about 50% for copper (about 30% being the average order of magnitude of the effect). The different between these values may arise from two causes. First, an element may absorb, selectively, neutrons of an energy far above thermal energy. The activity due to these neutrons will be independent of temperature, and the measured value of the temperature effect will be less than if the thermal neutrons alone had been concerned. Secondly, the variation of absorption probability with velocity may differ from one element to another in the "thermal region".
The theory of pressure-ionization and its applications
Authors: Kothari D. S.
Published: December 2006

It marked a significant advance in astrophysics when M. N. Saha first showed how the degree of ionization in stellar material could be calculated in terms of its temperature and pressure (or density). In the usual theory of thermal ionization the free electrons are treated as a
classical
perfect gas and, therefore, the theory is applicable only so long as the temperature and density of the material are such that the
free
electrons are
non-degenerate
in the sense of the Fermi-Dirac statistics. In the outer atmosphere of a star the condition of non-degeneracy is always satisfied, but in the interior of the white dwarf stars and the planets (and possibly in the interior of other stars as well) the conditions of temperature and density are such that the free electrons form a
degenerate
gas and their behaviour can no longer be described in terms of classical perfect gas. In the case of
cold
matter Saha’s theory loses its validity and the degree of ionization in degenerate matter must be investigated on other lines. This investigation of the ionization in degenerate matter is of importance in astrophysics, particularly in researches dealing with the internal constitution of the white dwarf stars and also, as has been recently shown (Kothari and Majumdar 1936
a
, 1936
b
; Kothari 1936), in predicting the maximum radius for a
cold
body.
Uranium Z and the problem of nuclear isomerism.
Authors: Feather Norman , Bretscher E.
Published: December 2006

It is well known that the idea of the possible isotopic complexity of the elements arose first as the result of investigations into the chemical behaviour of substances produced one from another in the course of successive radioactive transformations. Soon after this idea of isotopy had been generally accepted, Soddy (1917, 1919) suggested a further basis of classification which he believed might also be required in certain cases. According to this suggestion, nuclei which were indistinguishable in respect of charge and mass might still exhibit distinct radioactive properties, or might differ in “any new property concerned with the nucleus of the atom rather than its external shell”. He proposed in effect to classify distinct isotopic species as isobaric or heterobaric, depending upon whether the same or different mass numbers had to be assigned to them. In particular he suggested that the disintegrations of the branch products thorium C' and thorium C", which certainly result in isobaric species of the same atomic number, might in fact give rise to isotopes which were radioactively distinct. This suggestion was tested experimentally by S. Meyer (1918), but was not substantiated. Nevertheless, three years later, uranium Z was discovered by Hahn (1921)—and its chemical and radioactive properties interpreted by him as evidence for nuclear isomerism, in this case with uranium X
2
. Subsequent work by Hahn (1923), Guy and Russell (1923) and Walling (1931) confirmed this interpretation. Uranium Z and uranium X
2
were certainly isotopic, and as both were produced, as it seemed directly, from uranium X
1
the most natural assumption to make was that they were also isobaric. No further examples were found, however, and no attempt at a theoretical description of the phenomenon was made for some time. Then, in 1934, Gamow put forward an explanation based upon the idea of an additional fundamental particle, the negative proton, and, from the experimental side, the discovery of artificial radioactivity opened up entirely new possibilities of isotopy. Now, if v. Weizsäcker’s (1936) explanation of nuclear isomerism is generally preferred to Gamow's, at least it appears certain that several instances of the phenomenon are open to experimental study (Szilard and Chalmers 1935; Bothe and Gentner 1937; Meitner, Hahn and Strassmann 1937; Snell 1937). For that reason we have thought it important to begin such a study by a more detailed investigation than has hitherto been made of the radiations from uranium Z and the relations between this body and its neighbours in the series. The present paper describes the results of this investigation. So far as they have been taken they are distinctly favourable to v. Weizsäcker’s hypothesis; they suggest, therefore, that a precise statement of the hypothesis should be made the basis of our discussion.
Reaction chains in the thermal decomposition of hydrocarbons. A comparison of methane, ethane, propane and hexane
Authors: Hobbs J. E. , Hinshelwood Cyril Norman
Published: December 2006

The inhibition by nitric oxide of the thermal decomposition of ethane at 600° shows that the reaction proceeds partly by a chain mechanism, the apparent chain length, as measured by the ratio of the normal rate to that of the chain-free reaction, being of the order 5-15 over the range of pressure 50-500 mm., and falling with increasing pressure (Staveley 1937; Hobbs and Hinshelwood 1938). In passing up a homologous series of compounds the chain length may rise or fall. With the series of ethers, for examples, it decreases rapidly, whereas with the aldehydes it increases (Staveley and Hinshelwood 1937).
A study of the chain reaction in the thermal decomposition of diethyl ether.
Authors: Hobbs J. E.
Published: December 2006

In a recent paper (Hobbs and Hinshelwood 1938), information about the chain mechanisms involved in the thermal decomposition of ethane was obtained by studying the variation with the ethane concentration of the shape of the curve which represents in the reaction rate as a function of minute quantities of added nitric oxide. This paper describes the results of a similar investigation carried out with diethyl ether, the behaviour of which shows an interesting contrast with that of ethane. The thermal decomposition of diethyl ether in the neighbourhood of 500° C. occurs partly by a chain mechanism in which free radicals are formed, and partly by intramolecular rearrangement (Staveley and Hinshelwood 1936, 1937). The end- products of the decomposition are methane, ethane, and carbon monoxide, with small amounts of hydrogen and unsaturated substances. Acetaldehyde is an intermediate product formed either in the rearrangement process, or, as in the mechanism put formed below, during the chain reaction (Fletcher and Rollefson 1936). The acetaldehyde, however, decomposes rapidly under the experimental conditions and the initial rate is sensibly that of the decomposition of the ether into final products.
The molecular structures of carbon and silicon tetrafluorides.
Authors: Bailey C. R. , Hale J. B. , Thompson J. W.
Published: December 2006

The tetrahedral structure of the halides of Group IV is well established. The relation of the molecular constants to the force field governing the motion of the atoms is less certain; in particular, some difficulty has been found in reconciling the interatomic distances obtained by electrons diffraction with those deduced by other means. We have obtained certain of these molecular constants from an examination of the infra-red absorption spectra of gaseous carbon and silicon tetrafluorides. Preparative Carbon tetrafluoride was formed by the direct action of fluorine on carbon. The halogen was generated by the electrolysis of fused potassium bifluoride in a copper vessel, the anode being a graphite rod; the gas was passed through a hard glass tube packed with sodium fluoride and then through charcoal. A stream of dry nitrogen had been passed through the absorbents and the molten electrolyte for some hours. The resulting gas was condensed in a liquid air trap, and separated; after evaporation through silver nitrate solution to remove oxygen and silicon fluorides, and through soda-lime to remove hydrogen fluoride and CO
2
, it was again condensed and fractionally distilled, as far as was possible with the small yields obtained, over a small temperature range at about - 130° C.
On the theory of coincidence experiments on cosmic rays
Authors: Arley N.
Published: December 2006

It is now generally agreed that the cosmic radiation consists of two groups called the soft and the hard component. This classification refers to the penetrating power of the particles in question. The soft component consists of ordinary electrons and light quanta, whereas it now seems very probable that the hard group consists of "heavy electrons". The phenomena connected with the soft component are described by the cascade theory of showers put forward by Bhabha and Heitler (1937) and Carlson and Oppenheimer (1937). It is the purpose of the present paper to work out the consequences of the theory in greater detail in order to make possible a more quantitative comparison between theory and experiment than has hitherto been possible. This is desirable for several reasons: In the first place it is important to ascertain whether the phenomena connected with the soft component can be accountant for
completely
by the cascade theory or whether some of the facts require an explanation outside the present relativistic quantum mechanics.
Plan et essai d’un nouveau catalogue Sidéral, avec une réprésentation graphique, et une loi de simple et régulière distribution des étoiles autour du Pole, qui pourra fournir plusieurs avantages à l’Astronomie pratiques
Authors: Bianchini Joseph
Published: December 2006

The Author proposes the construction of a new sidereal catalogue, accompanied with a graphic representation of all the stars visible within the field of view at each observation, by means of the meri­dian transit of the most conspicuous stars across the field of a tele­scope of four inches aperture, attached to a three-feet circle. He directs this telescope to any elevation of the heavens that happens to be clear; and bringing any conspicuous star to the horizontal wire, he watches its transit over the two first vertical threads; then, suddenly intercepting the light, makes a diagram of all the stars in the field down to the 12th magnitude; and this he performs with suf­ficient expedition to enable him, on restoring the light, to observe the transit of his principal star over the fourth and fifth threads. The author has appended to the description of his method explana­tory drawings, displaying 600 fields, of which the principal star in each, has its right ascension and declination determined. He subjoins some remarks on the rate of clocks, as influencing the observations on the upper, lower, and opposite passages; and proposes a plan for a system of symbols expressive of the relative magnitude of the stars recorded in his catalogue. The author farther states as one of the most important results of his researches the probable existence of a general and curious law of position in the stars, namely, that they are distributed in pairs ; each star having a corresponding one in the opposite meridian, very nearly of she same declination and magnitude; a coincidence which he considers as extremely favourable to the execution of his project for the accurate determination of the position in the heavens of every star.
IX. On the development of the branches of the fifth cranial nerve in Man
Authors: Dixon A. Francis , Cunningham Daniel John
Published: December 2006

The investigation, the general results of which are summarised below, was suggested to the author by Professor His, and part of the work was carried on in his laboratory in Leipzig in the summer of 1893. Models were constructed of the cranial nerves in embryos of different ages, and the branches present noted and measured. These models were made up of glass plates, covered with varnish, on which were drawn the outlines of the sections and the positions of the nerves, &c. Detailed descriptions of the fifth nerve branches are given for five different stages of the human embryo, beginning with an embryo of four weeks, at which time merely the three main divisions of the nerve are represented, and ending with one of the eighth week.
A generalisation of the functions г(
n
) and

x
n

.
Authors: Jackson F. H. , Larmor Joseph
Published: December 2006

It is interesting to develope from simple principles a generalisation of the functions

x
n

and г(
n
). Consider an infinite sequence (1,
p
,
p
2
,
p
3
, . . .

p
n

, . . .), the write [1] = 1, [2] = 1+
p
, . . . . . . [
n
] = 1 +
p
+
p
2
+ . . . +
p

n
-1

(
n
positive and integral), [-
n
] = -
p
-1
-
p
-2
- . . . -
p

-
n

(
n
integral).
Enhanced Lines of titanium, iron, and chromium in the fraunhoferic spectrum.
Authors: Lockyer Joseph Norman , Baxandall F. E.
Published: December 2006

In previous publications it has been shown that the enhanced lines of some of the metals are prominent in the spectra of
α
Cygni and the sun’s chromosphere, while it is generally recognised that the lines in the Fraunhoferic spectrum are mainly the equivalents of lines in the arc spectra of metals.
On chemical combination and toxic action as exemplified in hæmolytic sera.
Authors: Muir Robert , Browning Carl Hamilton , Martin Charles James
Published: December 2006

It is now well known that the action of a hæmolytic serum depends upon two substances, viz.: (
a
) the immune-body, which is developed as the result of the injection of the red corpuscles of an animal of different species, and (
b
) the complement, a labile substance which is present in the serum of the normal animal, and which is not increased as the result of such injection.
On the structure and affinities of fossil plants from the palæozoic rocks.—V. On a new type of Sphenophyllaceous cone (
Sphenophyllum fertile
) from the lower coal-measures.
Authors: Scott Dukinfield Henry
Published: December 2006

The class Sphenophyllales, of which the fossil described is a new representative, shows on the one hand clear affinities with the Equisetales, while on the other it approaches the Lycopods; some botanists have endeavoured to trace a relation to the Ferns. The nearest allies among recent plants are probably the Psilotaceæ, which some writers have even proposed to include in the Sphenophyllales.
The halogen hydrides as conducting solvents.–Part IV. Preliminary notice.
Authors: Steele Bertram Dillon , M'Intosh D. , Archibald E. H. , Ramsay William
Published: December 2006

Recent investigations have shown that the power of forming conducting solutions is manifested to a greater or less extent by a large number of inorganic and organic solvents. Some of the resulting solutions behave in a similar manner to those in water, as regards the variation with dilution of the molecular conductivity
μ
, and of the average molecular weight of the dissolved substance. Others show a variation of
μ
which appears to be inconsistent with Arrhenius’ theory of ionic dissociation.
On the compressibility of gases between one atmosphere and half an atmosphere of pressure.
Authors: Strutt John William
Published: December 2006

The present memoir contains a detailed account of the observations referred to in the Preliminary Notice of February, 1904. In addition, results are now given for air, carbonic anhydride, and nitrous oxide. In the following table are recorded the values of B for the various gases at specified temperatures, B denoting the quotient of the value of
pv
at half an atmosphere by the value at the whole atmosphere:—