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Three side-chain liquid-crystalline polysiloxanes were prepared by hydrosilations of poly(dimethyl siloxane-co-methylhydro siloxane)s using a chiral smectic C vinyl monomer. All the polymers exhibit a subambient temperature glass transition, a chiral smectic C (SC*) and chiral smectic A (SA*) phase. The maximum spontaneous polarization (Ps) measured for the SC* phase of polymer 1b is 368 nC/cm2.

The dielectric loss spectrum of a side chain liquid crystal polymer (SCLCP) has been measured from 10 Hz to 100 kHz in the smectic phase. Three liquid crystalline siloxane polymers are examined, a ...

The dielectric relaxation study on a set of polyvinylether based cyanobiphenyl side chain liquid crystal polymers with three different alkyl spacer lengths of 7, 9, and 11 shows that the spacer decouples the motion of the mesogen from the polymer backbone so that both the low-frequency δ process and the high-frequency α process of the side group have been detected in smectic A phase. At a given temperature the relaxation frequency increases with spacer length for the α process. This trend is also observed for the λ process except for the longest spacer length.

The complex dielectric constant has been measured for a polyvinyl-ether based cyano-biphenyl side-chain liquid-crystalline polymer over the temperature range of 100-400 K and frequency range of 10-105 Hz. In the smectic-A phase, both homogeneous and homeotropic alignments were achieved with a 7-Tesla magnetic field by slowly cooling the samples down from the isotropic phase to room temperature. The low-frequency Δ loss peaks are suppressed in the homogeneous state and enhanced in the homeotropic state while high-frequency a loss peaks are enhanced in the homogeneous and almost absent in the homeotropic. The Arrhenius plot of each process shows a rapid decrease in the relaxation frequency as the temperature approaches T g, which may somehow reflect the glassy behavior of the polymer backbone and has been analyzed by WLF and Vogel-Fulcher equations. The results from two samples with different degree of polymerization are compared in terms of T g.

Broad band frequency (0.1 Hz-10 MHz) dielectric relaxation spectroscopy has been utilized to investigate nematic liquid crystalline polymethacrylates [CH 2 C(CH 3 )(COO[CH 2 ] 6 OPhCR=CR'PhOMe)] n (R= H, R'= Me, 4-6-PMA; R= Me, R'= H, 4'-6-PMA). While 4-6-PMA shows two typical relaxation process in a side-chain liquid crystalline polymer system, 4'-6-PMA essentially has one relaxation process. The temperature-dependent relaxation times, obtained through Havriliak-Negami data fitting, show «kinks» near calorimetric nematic-isotropic transition and a non-Arrhenius characteristic toward the glass transition. The glass behavior has been fitted with a Vogel-Fulcher-Tammann-Hesse (VFTH) equation and a general formula for activation energy has been derived in terms of VFTH parameters

Dielectric measurement on a polymer-dispersed liquid crystal (PDLC) has been carried out in the frequency range from 10 Hz to 1 MHz and over the temperature range from 100 to 330 K. The PDLC sample was prepared by thermally induced phase separation of a 50% mixture by weight of commercially available liquid crystal E7 with PMMA and was sandwiched between two indium tin oxide glass plates separated by 40 μm spacers to form a “window.” The dielectric spectrum at low temperature (220–250 K) shows two distinct relaxation processes. Which occur at about 5 K lower than those in pure E7 having Tg ≈ 209 K. From differential scanning calorimetry data, the nematic transition of LC droplets in the PDLC is at 258 K, about 6 K lower than that of pure E7. The Maxwell-Wagner effect has been observed in the low-frequency side as the temperature increases from 280 to 320 K. At room temperature, the loss peak associated with the Maxwell-Wagner effect shows an amplitude dependence with excitation level but no frequency shift. The effect of different concentrations of E7 in PDLC samples at a given temperature shows the 50% mixture has the “fastest” relaxation frequency in such a dispersed heterogeneous system. © 1992 John Wiley & Sons, Inc.

The millimeter-wave surface resistance of YBa2Cu3O(7-delta) superconducting films was measured in a gold-plated copper host cavity at 58.6 GHz between 25 and 300 K. High-quality laser-ablated films of 1.2-micron thickness were deposited on SrTiO3 and LaGaO3 substrates. Their transition temperatures were 90.0 and 88.9 K, with a surface resistance at 70 K of 82 and 116 milliohms, respectively. These values are better than the values for the gold-plated cavity at the same temperature and frequency.

It is shown that in the vicinity of 77 K beryllium has a superior specific conductance compared with the nominally excellent metallic conductors aluminum and copper. It is concluded that beryllium should be considered for some conduction applications, despite its well known toxicity problems.

Dielectric constants of microwave substrates are required in the design of superconducting microwave circuits at various temperatures. In this paper, the results are reported of a study of the complex permittivity of the newly developed lanthanum aluminate (LaAlO3) substrate, in the 20 to 300 K temperature range at frequencies from 26.5 to 40.0 GHz. The value of the complex permittivity was obtained by measuring the sample scattering parameters using a microwave waveguide technique. It is observed that, while the dielectric constant did not change appreciably with frequency, its value decreased by approximately 14 percent from room temperature to 20 K.

A retrospective study was performed at two teaching hospitals--one in the United States and one in Canada--to determine the results of computed tomography (CT) examinations of the head in patients with nontraumatic headache. Of 1111 examinations performed over a 3-year period, 120 (10.8%) demonstrated an acute intracranial abnormality, such as hemorrhage, infarction or tumour; the frequency of such abnormalities was highest among inpatients and subjects over 40 years of age. Cranial and extracranial abnormalities, such as sinusitis and metastases to the calvarium, were found in 40 (3.6%) of the cases. Chronic abnormalities, such as cerebral atrophy or remote infarction, were the most significant findings in 202 (18.2%) of the cases. The cost of finding each case of acute intracranial abnormality was $5962 (US); for subarachnoid hemorrhage among patients in the emergency department, it was $15,837 (US).

Two monoclonal antibodies designated BAT085 and G3-136 were raised by immunizing BALB/c mice with gp120 purified from human immunodeficiency virus type 1 (HIV-1) IIIB-infected H9 cell extracts. Among three HIV-1 laboratory isolates (IIIB, MN, and RF), BAT085 neutralized only IIIB infection of CEM-SS cells, whereas G3-136 neutralized both IIIB and RF. These antibodies also neutralized a few primary HIV-1 isolates in the infection of activated human peripheral blood mononuclear cells. In indirect immunofluorescence assays, BAT085 bound to H9 cells infected with IIIB or MN, while G3-136 bound to H9 cells infected with IIIB or RF, but not MN. Using sequence-overlapping synthetic peptides of HIV-1 IIIB gp120, the binding site of BAT085 and G3-136 was mapped to a peptidic segment in the V2 region (amino acid residues 169 to 183). The binding of these antibodies to immobilized gp120 was not inhibited by the antibodies directed to the principal neutralization determinant in the V3 region or to the CD4-binding domain of gp120. In a competition enzyme-linked immunosorbent assay, soluble CD4 inhibited G3-136 but not BAT085 from binding to gp120. Deglycosylation of gp120 by endo-beta-N-acetylglucosaminidase H or reduction of gp120 by dithiothreitol diminished its reactivity with G3-136 but not with BAT085. These results indicate that the V2 region of gp120 contains multiple neutralization determinants recognized by antibodies in both a conformation-dependent and -independent manner.

Trichroic infrared absorption has been measured for oriented phase I poly(vinylidene fluoride). In addition to intensity differences, frequency shifts in the plane transverse to the draw direction are apparent. Shifts up to 10 cm−1 in one-way drawn phase I are found for the CF2 stretching vibration (880 cm−1) between the direction normal to the film surface (thickness direction) and the remaining directions. Annealing the highly oriented films produces no major changes in the unique three-dimensional structure. A model based on crystal defect structures is proposed to explain the unusual frequency shift behavior in the phase I PVDF. Possible conformations and a mechanism of formation of the defects are discussed.

A de Haas-van Alphen study of the Laves phase, MgCu2, has been carried out by both pulsed field and torque methods. Although several features of the observed data correspond to similar features of the free-electron Fermi surface, constructed with eight valence electrons, no general correspondence can be established. A few representative cyclotron masses and Dingle temperatures are reported. One frequency branch with small cross-sectional area and relatively large cyclotron mass shows particular promise for future pressure - or stoichiometry-dependent studies.

Infrared spectra representative of crystalline regions of cast films of phase‐III poly(vinylidene fluoride) (PVF2) have been obtained by absorbance subtraction techniques using a FT‐IR instrument. The spectra contain more bands than previously reported and are not consistent with current models for the crystal structure. Several possible models and their relationship to the corresponding crystalline spectra of phase II and phase I are discussed.

Relaxin immunoactivaity concentrations in the peripheral sera been measured during pregnancy and parturition in rats with a homologous rat relaxin RIA. Relaxin was not detected until day 10 of pregnancy (day 10). Relaxin levels increased markedly over the next 4 days and generally ranged between 50-100 ng/ml from days 14-20. A prepartum surge in relaxin levels, which appeared to be associated with the photoperiod, occurred on day 21 in unanesthetized rats bled via indwelling jugular cannulas. Mean relaxin levels in these animals increased sharply from less than 80 ng/ml on day 20 to approximately 140 ng/ml at 1400 h on day 21 and declined to less than 60 ng/ml during the 12-24 h preceding parturition. The prepartum surge in relaxin immunoactivity may be associated with luteolysis, since there was an accelerated decline in progesterone concentrations concurrent with the prepartum relaxin surg. Rats also experienced a surge in relaxin concentrations during parturition. The mean maximal level of relaxin during parturition was approximately 180 ng/ml. The rate of decline of rat relaxin immunoactivity levels after bilateral ovariectomy on day 21 demonstrated characteristics of a multiexponential curve. The mean clearance t 1/2 from 0-30 min was 22 +/- 3 min (+/- SEM), and the mean t 1/2 from 30-180 min was 56 +/- 7 min (+/0 SEM).

The relationship of the antepartum elevation in serum relaxin levels in pregnant rats to luteolysis was examined by determining the effects of the luteolysin prostaglandin F2 alpha (PGF2 alpha) and the prostaglandin synthetase inhibitor indomethacin on antepartum serum relaxin levels, as well as on luteolysis and birth. Intravenous administration of PGF2 alpha on the morning of Day 20 elevated serum relaxin levels approximately fourfold within 15 min. Administration of the prostaglandin synthetase inhibitor indomethacin from Day 19 until Day 23 protracted luteolysis, delayed or prevented birth, and delayed the antepartum elevation of serum relaxin levels, until after indomethacin treatment had been terminated. Collectively, these results indicate that prostaglandins, in particular PGF2 alpha, may promote the antepartum increase in serum relaxin levels, as well as luteolysis and birth in rats.

Fermi-surface results in pure Mg, in alloys of Mg with 0.57 at.% Li and with 0.2 at.% In have been fit by a ten-plane-wave nonlocal-pseudopotential model with an accuracy of about 1%. The only adjustable parameter in each alloy is the Fermi level and this is determined by fitting a single de Haas-van Alphen frequency. It is found that changes in the Fermi surface arise from the shift of Fermi level, from lattice-spacing changes and from the effect of explicitly including the solute pseudopotential. Estimates of the Fermi-surface volume enable the hole and electron carrier concentrations in each alloy to be determined and show that the effective valence difference is very close to -1 and +1, respectively, for Li and for In.

Data for the stability of thin conductive indium tin oxide films on 0.003 inch thick Kapton substrates during exposure of the surface to electron beams are reported. The electron beam energy was 3 keV and the diameter was about 0.8 mm. Thermal effects and surface modifications are considered. For primary current greater than 0.6 microamperes, an obvious dark discoloration with diameter approximately that of the beam was produced. The structure of the discolored region was studied with the scanning electron microscope, and the findings are stated. Surface modifications were explored by AES, obtaining spectra and secondary emission coefficient as a function of time for different beam intensities. In all cases beam exposure results in a decrease of the secondary yield but because of thermal effects this change, as well as composition changes, cannot be directly interpreted in terms of electron beam dosage.

A commercial double-pass cylindrical mirror analyzer (CMA) and standard Auger electron spectroscopy electronics have been adapted to measure the low energy portion (< 100 eV) of the secondary electron distribution. Under normal operating conditions for the CMA, the presence of stray electric and magnetic fields within the CMA plus the poor electron multiplier response at low energy prevent measurements in the region where the secondary electron distribution reaches its maximum (< 5 eV). To circumvent this problem, we apply an accelerating potential (70 V) to the “retarding” grid at the entrance of the CMA. The accelerating potential translates the secondary electron distribution to high enough energies that the theoretical response of the CMA (E·N (E)) is valid, but low enough to give reasonable resolution. Moreover, we are able to separate the small tertiary electron peak due to the outer (grounded) grid by applying a small accelerating potential to the sample. This use of the CMA for measuring secondary electron distributions allows the surface to be characterized by AES before and after measurement. We present results for clean copper and silver. In the log N(E) versus log E format, we observe the linearized cascade with Auger peaks clearly visible.

The Fermi surface of beryllium has been throughly investigated by means of the de Haas-van Alphen effect, and the frequencies, though substantially in agreement with earlier measurements, have been obtained to greater accuracy. This has made it possible to construct a nonlocal pseudopotential model for the Fermi surface, in which the Fourier coefficients of the crystal potential are treated as parameters to be evaluated by fitting to the experimental data. In this way, all the principal cross sections of the surface have been fitted to within 1%, using only five adjustable parameters. Comparison of calculated cyclotron masses for these cross sections with the masses determined from the temperature dependence of the dHvA amplitudes indicates that the mass is enhanced about 20% by many-body interactions neglected in the model. Finally, the pressure dependence of the Fermi surface has been calculated and compared with some available experimental measurements.

The present investigation was commenced in 1932 and has been continued annually since that time with the object of determining the identity, host range, and geographic distribution of the Fusarium species in Canada. Approximately 9000 isolates of Fusarium were studied. These isolates were obtained from 173 species and botanical varieties of plants, 14 species of insects, and 4 of fungi. Of the various species and botanical varieties of plants from which isolates were obtained, 19 were cereals and grasses, 19 were vegetable crops, 15 were fruit crops, 13 were field crops, 52 were ornamental plants, 31 were trees and shrubs, and 24 were common weed plants. Less than 1% of the total isolates was obtained from insects and fungi. Although most of the isolates originated in Manitoba, some were obtained from each of the other provinces of Canada except Newfoundland.A total of 18 species, 3 varieties, and 18 formae of Fusarium, classified in nine sections of the genus, were identified among the isolates from plants, insects, and fungi. These species, varieties, and formae are: F. chlamydosporum Wr. & Rg., F. poae (Pk.) Wr., F. sporotrichioides Sherb. (section Sporotrichiella); F. arthrosporioides Sherb., F. avenaceum (Fr.) Sacc. (Roseum); F. concolor Rg., F. semilectum Berk. & Rav. (Arthrosporiella); F. acuminatum (Ell. & Ev.) Wr., F. eauiseti (Cda.) Sacc. (Gibbosum); F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. heterosporum Nees emend. Raillo, F. sambucinum Fuckel, F. samb. var. coeruleum Wr., F. samb. f. 6 Wr. (Discolor); F. moniliforme Sheld., F. moniliforme var. subglutinans Wr. & Rg. (Liseola); F. lateritium Nees (Lateritium); F. oxysporum Schl. emend. S. & H., F. oxysporum var. redolens (Wr.) Gordon, F. oxysporum f. betae (Stewart) S. & H., f. callistephi (Beach) S. & H., f. cepae (Hanz.) S. & H., f. conglutinans (Wr.) S. & H., f. dianthi (Prill. & Del.) S. & H., f. fabae Yu & Fang, f. gladioli (Massey) S. & H., f. lilii Imle, f. lini (Bolley) S. & H., f. lycopersici (Sacc.) S. & H., f. melonis S. & H., f. narcissi S. & H., f. pini (Hartig) S. & H., f. tuberosi S. & H. (Elegans); F. solani (Mart.) App. & Wr. emend. S. & H., F. solani f. eumartii (Carp.) S. & H., f. phaseoli (Burk.) S. & H., f. pisi (Jones) S. & H., F. coeruleum (Lib.) Sacc. (Martiella).F. chlamydosporum, F. heterosporum, F. moniliforme var. subglutinans, as well as 14 formae of F. oxysporum and 3 formae of F. solani, are reported to occur in Canada for the first time in this series of papers.The six species isolated most commonly, as indicated by the number of hosts from which they were obtained, are F. oxysporum, F. acuminatum, F. solani, F. equiseti, F. avenaceum, and F. poae.The conidia and chlamydospores of F. chlamydosporum and F. heterosporum are illustrated by drawings.

A study of the identity and prevalence of Fusarium species, isolated from 1448 farm samples of seed of common wheat, 262 of durum wheat, 865 of barley, and 519 of oats produced in Manitoba, was carried on during the six years 1937 to 1942. A total of 16 species, varieties, or forms of Fusarium, representing seven sections of the genus were isolated and identified. Fusarium Poae (Pk.) Wr., F. Equiseti (Cda.) Sacc., and F. Scirpi Lamb & Fautr. var. acuminatum (Ell. & Ev.) Wr. were the predominant species isolated. Fusarium species, one or more, were isolated from approximately 39% of the samples of common wheat, 38% of durum wheat, 55% of barley, and 59% of the samples of oats. The individual species of Fusarium were isolated from less than 1% of the seeds of the four crops, with the exception of F. Poae, which was isolated from 1.79% of the seeds of oats. Fusarium species, one or more, were isolated from approximately 0.66% of the seeds of common wheat, 0.50% of durum wheat, 1.23% of barley, and 2.21% of the seeds of oats.

A taxonomic study was made of 1348 isolates of Fusarium found in 206 soil samples collected in 1946. Approximately 70% of the samples, or 143, were obtained from 127 localities in Manitoba; the remaining 30%, or 63, came from seven other provinces.Of 25,973 colonies of fungi that developed on the 2060 soil-dilution plates involved in this study, Fusarium accounted for approximately 5%. A total of 14 species and varieties of Fusarium, classified in nine sections of the genus, were isolated; they are F. merismoides Cda., F. poae (Pk.) Wr., F. sporotrichioides Sherb., F. avenaceum (Fr.) Sacc., F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. equiseti (Cda.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. sambucinum Fuckel, F. sambucinum var. coeruleum Wr., F. moniliforme Sheld. emend. S. & H., F. oxysporum Schlecht. emend. S. & H., F. oxysporum var. redolens (Wr.) Gordon, F. solani (Mart.) App. & Wr. emend. S. & H. F. oxysporum, F. oxysporum var. redolens, F. equiseti, and F. solani accounted for approximately 90% of the total Fusarium isolates. F. oxysporum was by far the most prevalent species isolated. With the exception of F. merismoides, all of the species isolated were found previously to be seed-borne by cereals and to be associated with common root rot of those crops.

A list of 66 formae speciales of Fusarium oxysporum Schl. emend. S. & H. pr. p. is presented with their synonymy and hosts. Nine of these are new combinations and five are designated as new formae speciales. The present status of formae speciales as a taxon outside of the International Code of Botanical Nomenclature is discussed.

The third-zone Fermi surface of aluminum has been studied using the low-field de Haas\char22{}van Alphen effect. The observed de Haas\char22{}van Alphen periods have been assigned to the principal portions of the third-zone surface according to the model proposed by Ashcroft. Several cyclotron masses have been determined and are found to be consistent with cyclotron resonance results, where comparison is possible. de Haas\char22{}van Alphen cyclotron masses have been compared with the band-structure masses calculated by Ashcroft. This comparison indicates that, within the uncertainties in observed and calculated masses, there is a 30 to 50% enhancement of the band-structure masses over the third-zone surface, in agreement with the calculations of Ashcroft and Wilkins.

A taxonomic study was made of isolates of Fusarium obtained by the writer from various habitats in Trinidad, B.W.I., during the early months of 1955. Initial phases of this study were carried out at the Imperial College of Tropical Agriculture, Trinidad, while the later phases were completed at the Plant Pathology Laboratory, Winnipeg, Man. Isolates of Fusarium were obtained from a total of 41 different species and botanical varieties of host plants, from scale insects, and from soil. A total of 11 species and two varieties of Fusarium, classified in 10 sections of the genus, were identified among the various isolates. These sections, species, and varieties are: section Macroconia, F. coccophilum (Desm.) Wr. & Rg.; Spicarioides, F. decemcellulare Brick; Pseudomicrocera, F. coccidicola P. Henn.; Arachnites, F. larvarum Fuckel; Arthrosporiella, F. semitectum Berk. & Rav.; Gibbosum, F. equiseti (Cda.) Sacc.; Lateritium, F. lateritium Nees, F. stilboides Wr.; Liseola, F. moniliforme Sheld., F. moniliforme var. anthophilum (A. Br.) Wr., F. moniliforme var. subglutinans Wr. & Rg.; Elegans, F. oxysporum Schlecht. emend. Snyder & Hansen; Martiella, F. solani (Mart.) App. & Wr. emend. Snyder & Hansen. Six of these species are reported for the first time to occur in Trinidad, namely, F. coccophilum, F. decemcellulare, F. larvarum, F. equiseti, F. stilboides, and F. solani. Fusarium semitectum and F. moniliforme were most frequently encountered.The ascomycetous or perfect state of F. coccophilum, Nectria ecoccophila Wr.; of F. decemcellulare, Calonectria rigidiuscula (Berk. & Brme.) Sacc.; of F. moniliforme, Gibberella fujikuroi (Saw.) Wr.; and of F. solani, Hypomyces solani (Rke. & Berth.) emend. Snyder & Hansen were collected in nature.This paper is illustrated with drawings of the majority of the Fusarium species and the ascomycetous states mentioned.

The present taxonomic study involved approximately 1200 isolates of Fusarium which were received by the writer from time to time each year during the past 25 years from tropical and temperate regions. The various isolates originated in 59 geographic areas. Approximately 90% of the isolates were obtained from a total of 160 species of host plants which included cultivated and non-cultivated plants. The cultivated plants included the chief agricultural crops grown in tropical and temperate regions, respectively. About 10% of the isolates were obtained from miscellaneous habitats, e.g. soil, water, insects, wood pulp, fowl, dairy products, and human tissue.A total of 26 species, 4 varieties, and 17 formae of Fusarium, classified in 12 sections of the genus, were identified among the isolates. These species, varieties, and formae are: F. aquaeductuum (Radlk. & Rabh. pr.p) Lagh., F. dimerum Penz., F. merismoides Cda. (section Eupionnotes); F. decemcellulare Brick (section Spicarioides); F. nivale (Fr.) Ces. (section Arachnites); F. chlamydosporum Wr. & Rg., F. poae (Cda.) Sacc., F. sporotrichioides Sherb. (section Sporotrichiella); F. arthrosporioides Sherb., F. avenaceum (Fr.) Sacc. (section Roseum); F. semitectum Berk. & Rav. (section Arthrosporiella); F. acuminatum (Ell. & Everh.) Wr., F. compactum (Wr.) Gordon, F. equiseti (Cda.) Sacc, F. longipes Wr. (section Gibbosum); F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. heterosporum Nees emend. Raillo; F. sambucinum Fuckel, F. s. var. coeruleum Wr., F. s. forma 6 Wr., F. tumidum Sherb. (section Discolor); F. lateritium Nees, F. l. forma cajani (Padw.) Gordon, F. l. forma crotalariae (Padw.) Gordon, F. stilboides Wr. (section Lateritium); F. moniliforme Sheld., F. m. var. anthophilum (A. Br.) Wr., F. m. var. subglutinans Wr. & Rg. (section Liseola); F. oxysporum Schl. emend. Snyder & Hansen, F. oxysporum var. redolens (Wr.) Gordon; F. oxysporum forma callistephi (Beach) S. & H.; forma cepae (Hanz.) S. & H., forma dianthi (Prill. & Del.) S. & H., forma gladioli (Massey) S. & H., forma lini (Bolley) S. & H., forma lycopersici (Sacc.) S. & H., forma nicotianae (Johns.) S. & H., forma niveum (E. F. S.) S. & H., forma passiflorae Purss, forma pini (Hartig) S. & H., forma pisi (Lindf.) S. & H., forma tuberosi S. & H., forma vasinfectum (Atk.) S. & H. (section Elegans); F. coeruleum (Lib.) Sacc, F. solani (Mart.) App. & Wr. emend. S. & H. (section Martiella).As indicated by the number of geographic areas and habitats from which they were obtained, the six species most widely distributed were F. solani, F. oxysporum, F. equiseti, F. moniliforme, F. avenaceum, and F. semitectum. Five species, namely F. aquaeductuum, F. chlamydosporum, F. arthrosporioides, F. longipes, and F. tumidum, were encountered rarely, each being represented by a single isolate.

A study of the low-field de Haas-van Alphen effect in zinc, employing automatic recording of the variation of the torque as a function of the reciprocal of the applied magnetic field, has revealed six sets of periods. These periods are assigned in a consistent manner to portions of the free-electron (single orthogonalized planewave) model of the Fermi surface. Cyclotron masses associated with the three larger sets of observed periods are found to agree well with the theoretical estimates. Evidence is obtained for the presence of a spin-orbit energy gap across the hexagonal face of the first Brillouin zone near the corners. Thus, the validity of the single Brillouin-zone construction is demonstrated for zinc.

A taxonomic study was made of 12,485 isolates of Fusarium that were obtained from a total of 1674 soil samples taken from two series of permanent cereal plots during the years 1936–1942. Isolates of Fusarium averaged approximately 16% of total fungus isolates. A total of 16 species, varieties, and forms of Fusarium, classified in eight sections of the genus, were isolated. These species, varieties, and forms are F. dimerum Penz., F. merismoides Cda., F. poae(Pk.) Wr., F. sporotrichioides Sherb., F. avenaceum (Fr.) Sacc., F. concolor Rg., F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. equiseti (Cda.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. sambucinum var. coeruleum Wr., F. sambucinum f. 6 Wr., F. oxysporum Schlecht, em. Snyder & Hansen, F. oxysporum var. redolens (Wr.) Gordon, F. solani (Mart.) App. & Wr. em. Snyder & Hansen. The majority of the species isolated were encountered each year. F. oxysporum and F. equiseti, together, accounted for approximately 75% of the total Fusarium isolates. Average concentrations per gram of soil of these two species were approximately 4800 and 2300 'units', respectively. Average concentrations per gram of soil of each of the remaining species isolated were below 600 units. Except for F. dimerum and F. merismoides, the species, varieties, and forms that were obtained from soil have been isolated previously from the basal parts and seed of cereals in the Prairie Provinces.

During the present investigation, a total of 1579 seed samples of wheat, 1042 of barley, and 1152 of oats (100 kernels per sample), were examined microbiologically for the presence of Fusarium. Of these samples, 402 of wheat, 513 of barley, and 636 of oats originated in the seed inspection districts of Eastern Canada, and 1177 of wheat, 529 of barley, and 516 of oats in those of Western Canada. Isolates of Fusarium were obtained from approximately 41.8% of the samples of wheat (1.5% of the kernels), 76.2% of the samples of barley (3.9% of the kernels), and 79.6% of the samples of oats (5.7% of the kernels) that originated in Eastern Canada, whereas only 13,8% of the samples of wheat (0.2% of the kernels), 36.3% of the samples of barley (0.7% of the kernels), and 38.9% of the samples of oats (1.1% of the kernels) from Western Canada yielded Fusarium. In classifying the different wild types of Fusarium that were obtained from cereal seed the system of taxonomy and nomenclature of Wollenweber and Reinking was chiefly followed, but certain sections of the genus were revised extensively, partly in accordance with Snyder and Hansens' concept of species in this genus. Four new combinations are proposed, namely F. compactum (Wr.) n. eomb., F. lateritium Nees emend. Snyder & Hansen forma cajani (Padwick) n. comb., F. lateritium Nees emend. Snyder &. Hansen forma crotalariae (Padwick) n. comb., and F. oxysporum Schlecht. emend. Snyder & Hansen var. redolens (Wr.) n. comb. A total of 16 species and varieties of Fusarium, classified in nine sections of the genus, was isolated from cereal seed during this investigation. These species and varieties are, namely, F. poae (Pk.) Wr., F. sporotrichioides Sherb., F. avenaceum (Fr.) Sacc, F. arthrosporioides Sherb., P. semitectum Berk. & Rav., F. equiseti (Cda.) Sacc, F. acuminatum Ell. & Ev., F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. sambucinum Fuckel, F. sambucinum var. coeruleum Wr., F. lateritium Nees emend. Snyder & Hansen, F. moniliforme Sheld. emend. Snyder & Hansen, F. oxysporum var. redolens (Wr.) n. comb., and F. solani (App. & Wr.) Wr. emend. Snyder & Hansen. F. poae, F. avenaceum, and F. acuminatum were most frequently isolated. F. concolor Rg. and F. sambucinum f. 6 Wr,, that were previously recorded from cereal seed in Manitoba, and three additional species, namely, F. dimerum Penz., F. merismoides Cda., and F. nivale (Fr.) Ces., that may be encountered in the future among isolates from cereal seed in Canada, were also included in this study.

A taxonomic study was made of isolates of Fusarium obtained from a microbiological examination of seed from a total of 44 species and botanical varieties of cultivated plants. These plants may be classed as vegetable, forage, and miscellaneous crops. Most of the seed samples originated from stocks produced in Canada, but some were seed from other countries. A total of 16 species, varieties, and forms of Fusarium, classified in eight sections of the genus, were encountered among the isolates that were obtained from seed; they are F. poae (Pk.) Wr., F. sporotrichioides Sherb., F. arthrosporioides Sherb., F. avenaceum (Fr.) Sacc, F. semitectum Berk. & Rav., F. acuminatum Ell. & Ev., F. compactum (Wr.) Gordon, F. equiseti (Cda.) Sacc, F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. sambucinum Fuckel, F. sambucinum var. coeruleum Wr., F. moniliforme Sheld. em. S. & H., F. oxysporum Schlecht. em. S. & H., F. oxysporum f. lini (Bolley) S. & H., F. solani (Mart.) App. & Wr. em. S. & H. From the seed of a total of 44 species and botanical varieties of host plants, F. equiseti was identified among isolates from 34; F. poae and F. oxysporum each from 18; F. acuminatum from 17; F. avenaceum from 16; F. culmorum, from 10; F. sambucinum and F. moniliforme each from five; F. graminearum and F. sambucinum var. coeruleum each from four; F. solani from three; F. sporotrichioides from two; F. arthrosporioides, F. semitectum, F. compactum, and F. oxysporum f. lini each from one. The origin of the seed samples of each host is given.

Beta-microseminoprotein (beta-MSP), a sperm-coating antigen isolated from human seminal plasma, has apparent structural identity with "beta-inhibin" isolated from the same source. Publication of the amino acid sequence of beta-MSP revealed a greater than 96% homology with "beta-inhibin," with only a proline-threonine substitution at positions 39 and 40, and the omission of a glycine at position 93. Due to the nearly identical sequences of "beta-inhibin" and beta-MSP, we examined the ability of beta-MSP and its tryptic peptides to inhibit basal follicle-stimulating hormone (FSH) secretion from rat pituitary cells in culture, the inhibin bioassay. Whole pituitaries collected from 250- to 300-g male rats were dispersed enzymatically and plated onto 24-well culture dishes for 3 days. beta-MSP and its tryptic peptides were dissolved in cell culture medium, applied to the pituitary monolayer cell cultures, and incubated for an additional 3 days. FSH levels in the medium were determined by radioimmunoassay. A partially purified preparation of inhibin and our in-house inhibin standard, both prepared from porcine follicular fluid (pFFl), were included in the same assay. Whereas the partially purified inhibin from pFFl showed a dose-dependent inhibition of FSH secretion, with a 50% inhibitory dose (ID50) of 50 ng, which paralleled that of the standard, beta-MSP and its tryptic peptides failed to depress FSH levels in the medium at any of the doses tested (10-10,000 ng/ml). We conclude that beta-MSP is not an inhibin under our assay conditions.

The role of the maternal pituitary gland and LH in the regulation of the release of relaxin from the onset of the light phase on day 21 of pregnancy (day 21) until delivery (herein designated the antepartum period) was examined in rats. Serum relaxin levels were determined in rats hypophysectomized (HYPOX) or sham hypophysectomized (SHAM) on day 14. In SHAM rats, the elevated serum relaxin levels that occurred during the light phase of days 21 and 22 coincided with a rapid decline in serum progesterone to basal levels, and relaxin levels then declined markedly throughout the 18- to 24-h before delivery. During the antepartum period HYPOX rats differed from SHAM rats in the following ways: 1) mean serum relaxin levels were higher immediately before the antepartum period (day 20) and remained at the maximal levels the sham-operated animals experienced throughout the ensuing antepartum period; 2) elevations in relaxin levels generally occurred in individual rats; however, they usually occurred later than day...

A program to reduce unnecessary skull radiography for trauma was instituted in a teaching hospital in 1970 and eventually proved successful. In 1970, 2 976 skull examinations were made for all purposes and this fell to 791 examinations in 1983. A similar reduction occurred concurrently in the other university teaching hospital departments without the formal program. Only recently has this trend begun in urban hospitals and there is still no change in rural hospitals and urban private radiology offices. The reasons for the decline are attempts to moderate radiation dose, cost containment, clinical use of high yield criteria, and early employment of computed tomography head scanning for trauma. The savings in skull radiography match the related costs of computed tomography with improved patient care.

The binding characteristics of two highly purified preparations of follicle-stimulating hormone (FSH), one from equine (e) and one from porcine (p), were compared in a chicken testis radioreceptor assay. A two-component binding model was adequate to explain the binding of eFSH or pFSH to the chicken testis homogenate (CTH) FSH binding sites in the Scatchard study. The affinity of eFSH for the FSH binding site of CTH was 10-fold greater than that of pFSH by Scatchard analysis. This is consistent with the observation that in competitive protein binding studies approximately 10-fold greater quantities of pFSH were required to displace [125I] eFSH from the CTH FSH binding site than eFSH. Qualitatively, the order of relative potencies for various gonadotropin preparations was the same in either the CTH or a rat testis receptor radioligand assay. However, quantitatively, higher potency estimates were obtained with the CTH. The ability of LH preparations to displace radioiodinated pFSH or eFSH from CTH was generally very low with the notable exception of equine LH. The relative potency of highly purified eLH was approximately equal to that of the NIH-FSH-S16 standard (0.906 × NIH-FSH-S16) indicating that in the chicken, as in the rat, (Bousfield and Ward, Biochim. Biophys. Acta 885: 327, 1986), eLH has significant FSH activity. It is concluded that the chicken testis is a convenient and suitable source of FSH receptor (binding sites) for the bioassay of FSH, but that quantitative estimates of potency are not directly comparable when different sources of receptor are used. Finally the data show that eFSH has intriguing structural attributes which provide higher affinity to the chicken testis receptor than pFSH.

In a series of investigations between 1949 and 1958 an assessment was made of the medical, nursing, and social needs of Birmingham hospital patients (Lowe and McKeown, 1949; Garratt, Lowe, and McKeown, 1957, 1958a, b; McKeown, Mackintosh, and Lowe, 1961). The most significant finding was the heterogeneity of patients in each type of hospital?acute, mental, and chronic ?and it was suggested that patients should be regrouped to bring together those with similar needs. This idea led to the concept of a balanced hospital community: a hospital centre designed to accommodate all classes of patients from a defined population in multiple buildings on a common site (McKeown, 1958). The only patients not included in these proposals were the mentally subnormal. There were two reasons for this omission: there had been no investigation of the needs of the mentally subnormal in hospital; and it was thought advisable to allow a little time for appraisal of the idea of compre hensive responsibility for all other types of patients before considering the possibility of this addition. At the same time it was recognized that the case for classification of the mentally subnormal accord ing to their medical, nursing, and social needs, and for reappraisal of services in the light of such a classification, was particularly strong. There is wide variation in the care required by patients in the same hospital. Moreover, institutional provision for the mentally subnormal is deficient in quantity and quality, and raises staffing difficulties at least as serious as those in mental and chronic hospitals. This paper presents the results of an assessment of the type of care?medical, nursing, and social? required by all (1,652) Birmingham patients in local hospitals for the mentally subnormal. A

In early studies of the de Haas-van Alphen effect in zinc,1 it was found that the amplitude of the long period oscillations (which are now attributed to the needle-shaped electron portions in the third band) fell off unexpectedly with increasing magnetic fields. The solution of this puzzle was indicated by Stark’s2 identification of the occurrence of magnetic breakdown in magnetoresistance effects in zinc. The present work was initiated to further explore the influence of breakdown on these DHVA oscillations.

We have employed the de Haas-van Alphen effect (DHVA) to study the third zone portion of the Fermi surface of pure aluminum and of dilute alloys of zinc in aluminum.