A case of development of the parthenogenetic embryo in the ovary of Moina macrocopa Straus (Crustacea, Cladocera). [Translation from: Vest. Zool., Kiev 4, p. 86, 1971. ]

In a survey of histological preparations of several hundreds of Moina macrocopa Straus , one specimen was discovered, in the left ovary of which was found a parthenogenetic embryo. The short article includes an illustration of a transverse section of parthenogenetic female of Moina macrocopa.

Diurnal periodicity of activity in the spawning perch P. fluviatilis L. [Translation from: Kalamies 1972(7) 3, 1972]

Diurnal periodicity of spawning in the perch so far are rather meagre and found to be partly contrary to experiences of perch anglers. Therefore a study was made on the spawning during a 5-day period in the spring of 1971 in the Kuusamo area. Observations were made during the main spawning season, between 4- 9 June 1971. The perch were often measured, weighed and then released back into the water. The differences between spawning and non-spawning perch were studied as well as the time of roe discharge in a 24 hour period. Activity and environmental factors such as light intensity were also taken into consideration.

Efeitos cardiovasculares da transferência adotiva de linfócitos T reguladores em camundongos submetidos à infusão crônica de angiotensina II e de aldosterona

A angiotensina (Ang) II e aldosterona induzem hipertensão arterial por mecanismos em parte mediados pela imunidade adaptativa, envolvendo linfócitos T auxiliares respondedores (Tresp). Os linfócitos T reguladores (Treg) são capazes de suprimir os efeitos próinflamatórios do sistema imune. O presente estudo avaliou se a transferência adotiva de Treg é capaz de prevenir a hipertensão e a lesão vascular induzidas pela Ang II ou pela aldosterona, em dois protocolos distintos. No protocolo com Ang II, camundongos machos C57BL/6 sofreram a injeção endovenosa de Treg ou Tresp, sendo depois infundidos com Ang II (1μg/kg/min), ou salina (grupo controle) por 14 dias. No protocolo com aldosterona, um outro conjunto de animais sofreu injeções de Treg ou Tresp, sendo depois infundido com aldosterona (600μg/kg/d) ou salina (grupo controle), pelo mesmo intervalo de tempo. O grupo tratado com aldosterona recebeu salina 1% na água. Tanto o grupo Ang II como aldosterona apresentaram elevação da pressão arterial sistólica (43% e 31% respectivamente), da atividade da NADPH oxidase na aorta (1,5 e 1,9 vezes, respectivamente) e no coração (1,8 e 2,4 vezes, respectivamente) e uma redução da resposta vasodilatadora à acetilcolina (de 70% e 56%, respectivamente), quando comparados com os respectivos controles (P<0,05). Adicionalmente, a administração de Ang II proporcionou um aumento rigidez vascular (P<0,001), na expressão de VCAM-1 nas artérias mesentéricas (P<0,05), na infiltração aórtica de macrófagos e linfócitos T (P<0,001) e nos níveis plasmáticos das citocinas inflamatórias interferon (INF)-γ, interleucina (IL)-6, Tumor necrosis factor (TNF)-α e IL-10 (P<0,05). Ang II causou uma queda de 43% no número de células Foxp3+ no córtex renal, enquanto que a transferência adotiva de Treg aumentou as células Foxp3+ em duas vezes em comparação com o controle. A administração de Treg preveniu o remodelamento vascular induzido pela aldosterona, observado na relação média/lúmen e na área transversal da média das artérias mesentéricas (P<0,05). Todos os parâmetros acima foram prevenidos com a administração de Treg, mas não de Tresp. Estes resultados demonstram que Treg são capazes de impedir a lesão vascular e a hipertensão mediadas por Ang II ou por aldosterona, em parte através de ações antiinflamatórias. Em conclusão, uma abordagem imuno-modulatória pode prevenir o aumento da pressão arterial, o estresse oxidativo vascular, a inflamação e a disfunção endotelial induzidos por Ang II ou aldosterona.

Glycocalyx production in teleosts [Translation from: Verhandlungen der Deutschen Zoologischen Gesellschaft, p.286, 1970]

Shielding the organism against harmful effects from the environment is one of the most important tasks of the outer covering of all animals. The epidermis of primarily aquatic organisms and the epithelia of organs which are exposed to water, such as the digestive or the urinary system, possess a film of glycoproteins and mucopolysaccharides, the glycocalyx. This short paper examines the relationship of the mucus cells with the glycocalyx.

The family of chironomids or midges - Chironomidae. Keys to larvae and pupae [Translation from: Guide to the freshwater invertebrates of the European area of the USSR (Plankton and benthos) (ed. L. A. Kutikova and Ya. I. Starobogatov), p.371-431. Leningrad, Gidrometeoizdat, 1977]

The translation of this section of the larger publication ”Opredelitel' presnovodnykh bespozvonochnykh evropeiskoi chasti SSSR. (Plankton i bentos)” provides identification keys to the larvae and pupae of chironomids that occur in the Soviet Union. The morphology of the larvae of Chironomidae is described in the introductory part.

Taxonomic description of Peridinium lomnickii, P.lomnickii var. splendida and P. wierzejskii [Translation from: Flora Slodkowodna Polski. Tom 4. Cryptophyceae, Dinophyceae, Raphidoiphyceae, p326,328-330. Warsaw, 1974]

This partial translation from a larger paper provides taxonomic descriptions of the dinoflagellates Peridinium lomnickii, P.lomnickii var. splendida and P. wierzejskii. Illustrations are included.

Mellum Island (southern North Sea): dynamic processes and sedimentary structures. I. Southern tidal flat, transition zone and high-surface.[p.72 (Blasensand) only][Translation from: Senckenbergiana Maritima 11, 59-113, 1979]

This partial translation of a longer article describes the phenomenon of ”Blasensand”. Blasensand is formed when sedimentation of dried out sand is suddenly flooded from above. A more detailed explanation of Blasensand is given in this translated part of the paper.

Modelagem e otimização de misturas ternárias de polipropileno (PP), borracha de etileno-propileno-dieno (EPDM) e pó de pneu (SRT).

O aumento nos rejeitos industriais e a contínua produção de resíduos causam muitas preocupações no âmbito ambiental. Neste contexto, o descarte de pneus usados tem se tornado um grande problema por conta da pequena atenção que se dá à sua destinação final. Assim sendo, essa pesquisa propõe a produção de uma mistura polimérica com polipropileno (PP), a borracha de etileno-propileno-dieno (EPDM) e o pó de pneu (SRT). A Metodologia de Superfície de Resposta (MSR), coleção de técnicas estatísticas e matemáticas úteis para desenvolver, melhorar e optimizar processos, foi aplicada à investigação das misturas ternárias. Após o processamento adequado em extrusora de dupla rosca e a moldagem por injeção, as propriedades mecânicas de resistência à tração e resistência ao impacto foram determinadas e utilizadas como variáveis resposta. Ao mesmo tempo, a microscopia eletrônica de varredura (MEV) foi usada para a investigação da morfologia das diferentes misturas e melhor interpretação dos resultados. Com as ferramentas estatísticas específicas e um número mínimo de experimentos foi possível o desenvolvimento de modelos de superfícies de resposta e a otimização das concentrações dos diferentes componentes da mistura em função do desempenho mecânico e além disso com a modificação da granulometria conseguimos um aumento ainda mais significativo deste desempenho mecânico.

Experimental culture of algal balls (Cladophora sauteri). Retention of original shape [Translation from: Bull.Jap.Soc.Phycol. Vol. 10, (1), p. 23-27, 1962]

It was on July 1960 when 10 algal balls were acquired for exhibition at Suma Aquarium, Kobe. Permission to remove the specimens from the Lake Akan Reserve was given by the National Nature Reserve Committee. Algal balls, as a rule, lose their natural beauty when they are kept in an ordinary tank for a certain length of time. In an effort to retain the natural beauty it was decided to exhibit them in culture. This paper summarises the findings of this experiments with Cladophora sauteri. The author concludes that serious consideration has to be given as to the intensity of light, the sunlight, the water temperature and the nutrition for algal balls in culture in order to retain the natural beauty and shape.

Enzyme induction in Neurospora crassa

I. Studies on Nicotinamide Adenine Dinucleotide Glycohydrase (NADase)

NADase, like tyrosinase and L-amino acid oxidase, is not present in two day old cultures of wild type Neurospora, but it is coinduced with those two enzymes during starvation in phosphate buffer. The induction of NADase, like tyrosinase, is inhibited by puromycin. The induction of all three enzymes is inhibited by actinomycin D. These results suggest that NADase is synthesized de novo during induction as has been shown directly for tyrosinase. NADase induction differs in being inhibited by certain amino acids.

The tyrosinaseless mutant ty-1 contains a non-dialyzable, heat labile inhibitor of NADase. A new mutant, P110A, synthesizes NADase and L-amino acid oxidase while growing. A second strain, pe, fl;cot, makes NADase while growing. Both strains can be induced to make the other enzymes. These two strains prove that the control of these three enzymes is divisible. The strain P110A makes NADase even when grown in the presence of Tween 80. The synthesis of both NADase and L-amino acid oxidase by P110A is suppressed by complete medium. The theory of control of the synthesis of the enzymes is discussed.

II. Studies with EDTA

Neurospora tyrosinase contains copper but, unlike other phenol oxidases, this copper has never been removed reversibly. It was thought that the apo-enzyme might be made in vivo in the absence of copper. Therefore cultures were treated with EDTA to remove copper before the enzyme was induced. Although no apo-tyrosinase was detected, new information on the induction process was obtained.

A treatment of Neurospora with 0.5% EDTA pH 7, inhibits the subsequent induction during starvation in phosphate buffer of tyrosinase, L-amino acid oxidase and NADase. The inhibition of tyrosinase and L-amino acid oxidase induction is completely reversed by adding 5 x 10^-5M CaCl₂, 5 x 10^-4M CuSO₄, and a mixture of L-amino acids (2 x 10^-3M each) to the buffer. Tyrosinase induction is also fully restored by 5 x 10^-4M CaCl₂ and amino acids. As yet NADase has been only partially restored.

The copper probably acts by sequestering EDTA left in the mycelium and may be replaced by nickel. The EDTA apparently removes some calcium from the mycelium, which the added calcium replaces. Magnesium cannot replace calcium. The amino acids probably replace endogenous amino acids lost to the buffer after the EDTA treatment.

The EDTA treatment also increases permeability, thereby increasing the sensitivity of induction to inhibition by actinomycin D and allowing cell contents to be lost to the induction buffer. EDTA treatment also inhibits the uptake of exogenous amino acids and their incorporation into proteins.

The lag period that precedes the first appearance of tyrosinase is demonstrated to be a separate dynamic phase of induction. It requires oxygen. It is inhibited by EDTA, but can be completed after EDTA treatment in the presence of 5 x 10^-5M CaCl₂ alone, although no tyrosinase is synthesized under these conditions.

The time course of induction has an early exponential phase suggesting an autocatalytic mechanism of induction.

The mode of action of EDTA, the process of induction and the kinetics of induction are discussed.

Class two p groups as fixed point free automorphism groups

Suppose that AG is a solvable group with normal subgroup G where (|A|, |G|) = 1. Assume that A is a class two odd p group all of whose irreducible representations are isomorphic to subgroups of extra special p groups. If p^c ≠ r^d + 1 for any c = 1, 2 and any prime r where r^2d+1 divides |G| and if C_G(A) = 1 then the Fitting length of G is bounded by the power of p dividing |A|.

The theorem is proved by applying a fixed point theorem to a reduction of the Fitting series of G. The fixed point theorem is proved by reducing a minimal counter example. IF R is an extra spec r subgroup of G fixed by A₁, a subgroup of A, where A₁ centralizes D(R), then all irreducible characters of A₁R which are nontrivial on Z(R) are computed. All nonlinear characters of a class two p group are computed.

Spontaneous and stimulated light emission due to radiative recombination in forward biased lead telluride P-N junctions

Since the discovery in 1962 of laser action in semiconductor diodes made from GaAs, the study of spontaneous and stimulated light emission from semiconductors has become an exciting new field of semiconductor physics and quantum electronics combined. Included in the limited number of direct-gap semiconductor materials suitable for laser action are the members of the lead salt family, i.e . PbS, PbSe and PbTe. The material used for the experiments described herein is PbTe . The semiconductor PbTe is a narrow band- gap material (E_g = 0.19 electron volt at a temperature of 4.2°K). Therefore, the radiative recombination of electron-hole pairs between the conduction and valence bands produces photons whose wavelength is in the infrared (λ ≈ 6.5 microns in air).

The p-n junction diode is a convenient device in which the spontaneous and stimulated emission of light can be achieved via current flow in the forward-bias direction. Consequently, the experimental devices consist of a group of PbTe p-n junction diodes made from p –type single crystal bulk material. The p - n junctions were formed by an n-type vapor- phase diffusion perpendicular to the (100) plane, with a junction depth of approximately 75 microns. Opposite ends of the diode structure were cleaved to give parallel reflectors, thereby forming the Fabry-Perot cavity needed for a laser oscillator. Since the emission of light originates from the recombination of injected current carriers, the nature of the radiation depends on the injection mechanism.

The total intensity of the light emitted from the PbTe diodes was observed over a current range of three to four orders of magnitude. At the low current levels, the light intensity data were correlated with data obtained on the electrical characteristics of the diodes. In the low current region (region A), the light intensity, current-voltage and capacitance-voltage data are consistent with the model for photon-assisted tunneling. As the current is increased, the light intensity data indicate the occurrence of a change in the current injection mechanism from photon-assisted tunneling (region A) to thermionic emission (region B). With the further increase of the injection level, the photon-field due to light emission in the diode builds up to the point where stimulated emission (oscillation) occurs. The threshold current at which oscillation begins marks the beginning of a region (region C) where the total light intensity increases very rapidly with the increase in current. This rapid increase in intensity is accompanied by an increase in the number of narrow-band oscillating modes. As the photon density in the cavity continues to increase with the injection level, the intensity gradually enters a region of linear dependence on current (region D), i.e. a region of constant (differential) quantum efficiency.

Data obtained from measurements of the stimulated-mode light-intensity profile and the far-field diffraction pattern (both in the direction perpendicular to the junction-plane) indicate that the active region of high gain (i.e. the region where a population inversion exists) extends to approximately a diffusion length on both sides of the junction. The data also indicate that the confinement of the oscillating modes within the diode cavity is due to a variation in the real part of the dielectric constant, caused by the gain in the medium. A value of τ ≈ 10^-9 second for the minority- carrier recombination lifetime (at a diode temperature of 20.4°K) is obtained from the above measurements. This value for τ is consistent with other data obtained independently for PbTe crystals.

Data on the threshold current for stimulated emission (for a diode temperature of 20. 4°K) as a function of the reciprocal cavity length were obtained. These data yield a value of J’_th = (400 ± 80) amp/cm² for the threshold current in the limit of an infinitely long diode-cavity. A value of α = (30 ± 15) cm^-1 is obtained for the total (bulk) cavity loss constant, in general agreement with independent measurements of free- carrier absorption in PbTe. In addition, the data provide a value of n_s ≈ 10% for the internal spontaneous quantum efficiency. The above value for n_s yields values of t_b ≈ τ ≈ 10^-9 second and t_s ≈ 10^-8 second for the nonradiative and the spontaneous (radiative) lifetimes, respectively.

The external quantum efficiency (n_d) for stimulated emission from diode J-2 (at 20.4° K) was calculated by using the total light intensity vs. diode current data, plus accepted values for the material parameters of the mercury- doped germanium detector used for the measurements. The resulting value is n_d ≈ 10%-20% for emission from both ends of the cavity. The corresponding radiative power output (at λ = 6.5 micron) is 120-240 milliwatts for a diode current of 6 amps.

Measurements of mantle velocities of P waves with a large array

A large array has been used to investigate the P-wave velocity structure of the lower mantle. Linear array processing methods are reviewed and a method of nonlinear processing is presented. Phase velocities, travel times, and relative amplitudes of P waves have been measured with the large array at the Tonto Forest Seismological Observatory in Arizona for 125 earthquakes in the distance range of 30 to 100 degrees. Various models are assumed for the upper 771 km of the mantle and the Wiechert-Herglotz method applied to the phase velocity data to obtain a velocity depth structure for the lower mantle. The phase velocity data indicates the presence of a second-order discontinuity at a depth of 840 km, another at 1150 km, and less pronounced discontinuities at 1320, 1700 and 1950 km. Phase velocities beyond 85 degrees are interpreted in terms of a triplication of the phase velocity curve, and this results in a zone of almost constant velocity between depths of 2670 and 2800 km. Because of the uncertainty in the upper mantle assumptions, a final model cannot be proposed, but it appears that the lower mantle is more complicated than the standard models and there is good evidence for second-order discontinuities below a depth of 1000 km. A tentative lower bound of 2881 km can be placed on the depth to the core. The importance of checking the calculated velocity structure against independently measured travel times is pointed out. Comparisons are also made with observed PcP times and the agreement is good. The method of using measured values of the rate of change of amplitude with distances shows promising results.

Part I: Total yield measurements for the ^(21)Ne(α,n)^)(24)Mg reaction. Part II: A study of the ^(12)C(He,p)^(14)N reaction

PART I

The total cross-section for the reaction ²¹Ne(α, n)²⁴Mg has been measured in the energy range 1.49 Mev ≤ E_cm ≤ 2.6 Mev. The cross-section factor, S(O), for this reaction has been determined, by means of an optical model calculation, to be in the range 1.52 x 10¹² mb-Mev to 2.67 x 10¹² mb-Mev, for interaction radii in the range 5.0 fm to 6.6 fm. With S(O) ≈ 2 x 10¹² mb-Mev, the reaction ²¹Ne(α, n)²⁴Mg can produce a large enough neutron flux to be a significant astrophysical source of neutrons.

PART II

The reaction¹²C(³He, p)¹⁴N has been studied over the energy range 12 Mev ≤ E_lab ≤ 18 Mev. Angular distributions of the proton groups leading to the lowest seven levels in ¹⁴N were obtained.

Distorted wave calculations, based on two-nucleon transfer theory, were performed, and were found to be reliable for obtaining the value of the orbital angular momentum transferred. The present work shows that such calculations do not yield unambiguous values for the spectroscopic factors.