bluuebunny/crossref_metadata_2025 huggingface dataset:
Empresas startups: análise do ciclo de vida a partir do modelo de Lester, Parnell e Carraher (2003)
Authors: Silva Edmilson Estevão da , Krakauer Patricia Viveiros de Castro , Coda Roberto
Published: May 2020

Objetivo do estudo: Esta pesquisa busca identificar quais estágios do modelo de ciclo de vida organizacional (CVO) de Lester, Parnell e Carraher (2003) são pertinentes às startups brasileiras e tem como objetivo: (i) identificar os estágios do CVO existentes em startups e (ii) apresentar recomendações estratégicas para cada estágio. Metodologia/abordagem: Trata-se de uma pesquisa com abordagem descritiva, não paramétrica, sendo utilizada a escala do tipo likert de questionário já validado em pesquisas anteriores, acrescido de perguntas sociodemográficas. Obteve-se 118 respostas válidas. Os dados foram analisados conforme o método de análise proposto por Frezatti et al. (2010), que preconiza que as questões inclusas no questionário possuem relação com os estágios do ciclo de vida do modelo de Lester, Parnell e Carraher (2003). Originalidade/Relevância: Diversos autores escreveram sobre o CVO, voltando suas pesquisas para pequenas ou grandes empresas e empresas familiares, porém não foi encontrado um modelo de CVO específico para startups, conforme pesquisa bibliográfica realizada como parte da investigação teórica deste estudo. Principais resultados: 118 respostas válidas foram obtidas. A análise dos resultados indica que nem todos os estágios existentes no modelo teórico de CVO existiam na amostra de startups investigada. Foram identificados os estágios de nascimento, crescimento e declínio e, a partir de tal constatação, foram feitas recomendações estratégias possíveis em cada um dos estágios. Contribuições teóricas/metodológicas: Os resultados obtidos com esta pesquisa podem ser aplicados por startups que busquem longevidade, a partir do entendimento do seu ciclo de vida e de possíveis estratégias pertinentes a cada fase identificada.
Cognição empreendedora: elementos cognitivos que influenciam a exploração de oportunidades
Authors: Behling Gustavo , Lenzi Fernando César
Published: May 2020

Objetivo do estudo: Apresentar uma abrangente revisão de literatura sobre os elementos cognitivos que influenciam os modelos mentais de empreendedores na exploração de oportunidades.Metodologia/abordagem: Os procedimentos metodológicos empregados nesta pesquisa bibliográfica foram divididos em: 1. Formulação da questão de pesquisa, 2. Localização dos estudos, 3. Seleção e avaliação dos estudos, 4. Análises e síntese e 5. Relato dos resultados. A busca dos estudos resultou em 87 artigos identificados. Na etapa de seleção e avaliação, 36 artigos foram excluídos devido à falta de aderência à temática pretendida. Com 51 artigos selecionados, foi realizada uma leitura criteriosa dos documentos. Por fim, os autores realizaram a revisão e análise apresentada nos resultados.Originalidade/Relevância: Há uma carência de estudos sobre como variações em elementos cognitivos moldam as percepções dos empresários sobre oportunidades empreendedoras. O estudo evidencia a diversidade de oportunidades de pesquisa em cognição empreendedora, contribuindo para o campo de estudos. Principais resultados: O artigo apresenta dez características cognitivas de empreendedores que suportam seus modelos mentais e influenciam o processo de exploração de oportunidades. A partir das análises destas características, são sugeridas oito proposições teóricas a serem testadas empiricamente que podem gerar um melhor entendimento sobre os modelos mentais de empreendedores. Contribuições teóricas/metodológicas: A revisão de literatura apresentada, e em maior grau as proposições levantadas a partir desta, revela uma série de lacunas de pesquisa e pontos que carecem de aprofundamento em estudos empíricos para desenvolver um melhor entendimento sobre como características cognitivas interferem na identificação e exploração de novos de negócios.
The Development of Dam Infrastructure Condition and Safety Assessment
Authors: Jayadi Muchammad Sarwono Purwa , Wirahadikusumah Reini D. , Harlan Dhemi
Published: May 2020

AbstractThe management and regulation of large inventories of embankment dams requires the use of tools and analytical techniques that can provide a uniform basis for comparison. Index Condition and Risk Assessment were two of those tools. Those two assessment can be combined to make an comprehensive assessment because it's main data are visual condition of dam. With those similarity, how to develop dam assessment based on dam's condition and safety are the main goals of this research. On these research, Condition Index with index from 1 to 5 are used for the condition assessment. Meanwhile, ICOLD Modified Method are used as safety evaluation aspect. Those two assessment system were combined using Analytic Hierarchy Process (AHP) to find it's weight for the assessment model. AHP were used to analyze AHP's linear scale questionnaire as primary data. These research obtain that the developed model had some limitations, so the assessment aren't comprehensive enough.AbstrakManajemen dan regulasi dari inventaris bendungan besar membutuhkan alat dan teknik analisis yang dapat memberikan dasar yang seragam untuk perbandingan. Penilaian Kondisi berbasis Indeks Kondisi dan Kajian Keamanan berbasis Indeks Risiko merupakan beberapa contoh dari alat tersebut. Kedua penilaian ini sebenarnya bisa digabungkan untuk mendapatkan penilaian yang komprehensif karena menggunakan kondisi visual sebagai salah satu data utama. Dengan adanya kesamaan tersebut, bagaimana cara mengembangkan penilaian kondisi dan keamanan bendungan merupakan tujuan utama dari penelitian ini. Dalam penelitian ini, Indeks Kondisi dengan indeks nilai 1 sampai 5 digunakan sebagai penilaian dalam aspek penilaian kondisi. Sedangkan dalam aspek kajian keamanan, digunakan Metode ICOLD Modifikasi. Dalam menggabungkan kedua sistem penilaian tersebut, Analytic Hierarchy Process (AHP) digunakan untuk mendapatkan bobot penilaian bendungan. Berdasarkan hasil analisis, model yang dikembangkan memiliki  beberapa limitasi sehingga penilaian belum cukup komprehensif.
Perceiving Matter. Visual, Material and Sensual Communication – an Introduction
Authors: Kollandsrud Kaja , Kiilerich Bente
Published: May 2020

A consistent line of thinking about matter, colour and form continued into the Middle Ages from the Classical period. Our present views on the Classical and medieval works of art are coloured by how they have been perceived throughout their timeline. Therefore, it is fruitful to discuss polychromy in a broader historical context. The idea for this special issue came about when researchers specializing in ancient and medieval polychromy met for the first time at the seminar Perceiving matter. Visual, material and sensual communication from Antiquity to the Middle Ages and Beyond, held at the Museum of Cultural History, 5 April 2019 under the auspices of the Polychrome Art History Research Group. Marina Prusac Lindhagen initiated the seminar and invited Kaja Kollandsrud to co-organise the event.
PREPARATION OF DYED AZOLIGNINS ON LINEN COTTONIN MODIFIED BY ENZYMES
Authors: Loginova Vera A. , Cheshkova Anna V. , Frolova Tatyana S.
Published: May 2020

The possibility of using azoreaction for obtaining colored like-cotton flax (cottonin) are evaluated in this article. For the process of disfiling (disfibering, disenchantment) enzymes Pulpzyme HC and Scourzyme L ("Novozymes A/S" (Denmark)) were applied. Diazol scarlet K was used as a diazo component. It is established that the enzymatic modification of ligno-carbohydrate complex promotes opening phenolic hydroxyls. As a result, the reactivity of flax fiber with respect to diazol alum K increases. The spectra of dyed extracted polyphenols of flax were obtained and interpreted for region of 400-700 nm. It was shown that in the spectra of extractive aromatic substances of phenolic nature for the native fiber two maxima at 420-440 nm and 500-520 were appeared nm during the azo coupling reaction. The first maximum corresponds to the compounds formed as a result of the reaction of azo combination with aromatic substances having unexpressed color (chromophore). The long-wave maximum is associated with azo lignins, where the associated and non-associated complexes of aromatic polyphenols of lignin act as the diazocomponent. It is assumed that enzymatic hydrolysis of non-cellulose polysaccharides creates stereo accessibility to the reaction groups of lignin, which is part of the structure of the ligno-carbohydrate complex of flax fiber. The dependence of the function K/S – (K/S)0 for colored flax fibers at different modification methods were obtained and interpreted. The effect of lignin unblocking in after enzymatic cottonization is confirmed. There is a significant increase in the K/S function of colored cottonin in comparison with the results for native short flax fiber. The method of spectrophotometry proved that the maximum effect of color dyeing is provided in the case of the enzymatic modification of Pulpzyme NS if excluded of the washing stage.
INFLUENCE OF ALUMINUM POWDER CONCENTRATION ON MECHANISM AND KINETIC REGULARITIES OF CRYSTALLIZATION OF COMPOSITES BASED ON LOW DENSITY POLYETHYLENE
Authors: Kakhramanov Najaf T. , Allakhverdieva Khayala V. , Mustafayeva Fatima A. , Abdullin Marat I.
Published: May 2020

The results of the study of the influence of the aluminum powder concentration on the mechanism and the regularity of changes in the dependence of specific volume on temperature in the range of 25-180 °C in composites based on low density polyethylene are presented. By extrapolating the upper and lower branches of the dilatometric curve, approximate values of the glass transition temperature of the composites are found. Extrapolation of the lower branch of the dilatometric curve of the considered polymer composites to the absolute temperature allowed us to determine the value of the "occupied" specific volume and the "free" specific volume. Using the step dilatometry method, the temperature of the first-order phase transition of composites was found, which varies depending on the aluminum powder concentration in the composition of low density polyethylene. The concentration of aluminum powder with a particle size 1-2 µm varied between 0.5 – 30 wt. %. It has been established that the loading of 0.5 wt. % of aluminum powder practically does not affect the regularity of change in the dilatometric curve of the initial polymer matrix. At a filler concentration of 1.0 wt. % and higher, a significant change occurs in the regularities of change in these curves, expressed in a decrease in the value of the specific volume of the composites. A sharp decrease in the specific volume or an increase in the density of the composites in viscous-flow and solid states clearly indicated the reinforcing role of aluminum powder. In composites based on low density polyethylene, the dependence of the free specific volume on temperature and on the concentration of aluminum powder is determined. It is shown that an increase in the concentration of aluminum powder in the composition of low density polyethylene is accompanied by a regular decrease in the free volume of the polymer matrix. The obtained data confirms our idea that particles of aluminum powder are involved not only in the formation of heterogeneous crystallization centers, but are also forced into the amorphous region as the spherolite crystalline formations grow. In the coordinates of Avraami, the kinetic regularities of the process of isothermal crystallization in the region of the first-order phase transition are investigated. It has been established that with an increase in the degree of filling of the polymer matrix, the mechanism of crystallization from spherical (three-dimensional) type of growth of crystalline formations passes into a plate-like (two-dimensional) with the continuous formation of crystallization centers. Recommendations are given on the practical use of the results of a study of the crystallization process of composites as applied to the technology of their processing by injection molding.
INFLUENCE OF THE AUTOCATALYTIC STAGES ON THE DYNAMICS OF CONJUGATED CHEMICAL REACTIONS
Authors: Fedotov Vladislav Kh. , Kol'tsov Nikolay I. , Kosianov Petr M.
Published: May 2020

Chemical reactions occurring on nonlinear mechanisms, containing the stage of interaction of various reagents (feedback), can exhibit unusual kinetic properties - the multiplicity of equilibria (hysteresis of different shape dependency on the «velocity-parameter»), change the time of the motion to the equilibrium (slow or fast relaxation), sustained oscillations (regular, irregular), etc. All these critical phenomena are usually associated with the appearance of unstable equilibria in the reactions under study. From the kinetic point of view, one of the main causes of instability is the presence of autocatalytic stages in the reaction mechanism. Therefore, it is interesting to study the effect of autocatalytic stages on the kinetics of chemical reactions, especially far from equilibrium. In this regard, the dynamic characteristics of typical conjugate reactions occurring by non-autocatalytic and autocatalytic mechanisms in an isothermal reactor of ideal mixing under the same conditions are compared in this paper. It is shown that the kinetics of these reactions is different: autocatalysis can shift the equilibrium, change the relaxation time and the rate of reactions. In an irreversible consecutive reaction (far from equilibrium) autocatalysis shifts the equilibrium in the direction of increasing the proportion occupied by the surface of the catalyst and the reaction rate dominated by positive autocatalysis. As the reversible processes increase, the balance shifts to the other side, the reaction slows down and autoinhibition begins to prevail. In parallel conjugate reactions, negative autocatalysis is not observed. In both types of the considered conjugate reactions, the maximum positive change in concentrations and velocity due to autocatalysis observed when these reactions are irreversible.
VOLUMETRIC PROPERTIES OF ACRYLONITRILE+ETHANOL MIXTURE OVER TEMPERATURE RANGE FROM (293.15 TO 323.15) K AT AMBIENT PRESSURE
Authors: Ghazoyan Heghine H.
Published: May 2020

Densities of binary mixture of acrylonitrile in ethanol have been measured over the full range of compositions at temperatures from 293.15K to 323.15 K at the ambient pressure (87.9 kPa). The volumetric properties such as excess molar volumes, apparent molar volumes, partial molar volumes, excess partial molar volumes, standard partial molar volumes for binary mixture were calculated. Excess molar volumes were described by the Redlich–Kister polynomial equation. The Redlich–Kister coefficients and the standard deviations were calculated as well. The excess molar volumes exhibit mainly negative deviations from the ideal behavior over the whole range of composition for acrylonitrile+ethanol binary mixtures at low temperatures and become less negative with increasing temperature from 293.15 to 323.15 K. The results are interpreted on the basis of strong interaction between group of acrylonitrile and OH group of ethanol by hydrogen bonding. However, the sigmoid shape of plots of excess molar volumes versus molar fraction of ethanol from positive to negative values indicates to the varying interactions depending upon the composition of binary mixtures. Moreover, it is also attributed to the self-associating effect of ethanol therefore the self-associates of acrylonitrile by dipole-dipole interactions and the self-associates of ethanol by hydrogen bonding between same molecules at low concentrations predominate too.
HEAVY METAL REMOVAL BY CELLULOSE-BASED TEXTILE WASTE PRODUCT
Authors: Pugacheva Inna N. , Karmanov Andrei V. , Zueva Svetlana B. , Michelis Ida De , Ferella Francesco , Vegliò Francesco , Molokanova Larisa V.
Published: May 2020

The textile industry is a source of significant amounts of cellulosic waste that can be processed into promising sorbents. The aim of study was understanding the adsorption behavior of metal ions on cellulose surfaces obtained from cellulose textile waste of light industry. Previous studies have shown that unmodified cellulose-based ion exchange resins obtained at different pH values were able to remove metal ions from aqueous solution. In present work the cellulose-based ion exchange resins were prepared by H2SO4 hydrolysis of initial waste product with following neutralization up to different pH and drying at 80 °C. Based on the fractional composition of powdered sorbents, the weighted average particle size of the sorbents used is determined: sorbents with pH = 1.5 - 3 ≈ 0.57 mm; sorbents with pH = 5 - 7 ≈ 0.14 mm. The IR analysis of the elemental composition of the particles showed the presence of bound sulfate groups in the powder sorbent with pH = 1.5-3. The results of experiments showed that the modification of the surface of the cellulose waste with sulfuric acid increased the effect of adsorption of Ni, Fe and Pb ions from an aqueous solution. It has been established that the electrostatic interaction between surface functional groups plays a significant role in the adsorption properties of the sorbents obtained. The affinity of sulphonic acid resins for cations generally varies with the ionic size and charge of the cation. This study showed that adsorption capacities of studied metals were in the order of Fe3+<Pb2+<Ni2+. Resulting cellulose particles have sulfate groups on their surface, which have wide range of applications for the removal of heavy metal ions from wastewater.
NITROGEN-DOPED TITANIUM DIOXIDE NANOFILMS FOR MEDICAL APPLICATION
Authors: Boytsova Elena L. , Leonova Lilia A. , Pustovalova Alla A.
Published: May 2020

The results of study of nitrogen-containing titanium dioxide nanofilms (N-TiO2) are presented in this work. These nanofilms are used in biomedicine as a biocoating of the implants that is why the problem of increasing resistance is very essential. Biocoatings were deposited by reactive magnetron sputtering at different bias voltages Ub = 0-100 V. Doping of the oxide film with nitrogen, with technological replacement of oxygen by nitrogen atoms, changes the material properties: antithrombogenic qualities appear and hemocompatibility rates increase. The corrosion resistance rates of the film are also increased. The biocoatings are partially dissolved, when interacting with biological fluids, with a further release/formation of compounds with an N-O bond, which are essential for human activity. X-ray diffraction (XRD) was used to study the phase transition and crystallinity of nanofilms. The rutile phase dominates (68%) when a negative bias in these films was used. The volume of the fraction increases permanently with increasing of nitrogen content in the composition of the reactive gas, while the volume fraction of anatase decreases to 10%. The surface morphology was studied using scanning electron microscopy. It was established that the films have a more fine-grained structure than at the displacement equals zero. Chemical stability and the presence of elements were observed using X-ray fluorescence spectrometry (XFS) and atomic emission spectrometry (AES). The results of measurement of the contact angle and the surface energy are presented. The results of the study showed the influense of bias voltage on the phase composition, surface morphology and chemical properties of N-TiO2 nanofilms. The analysis of the results suggests that N-TiO2 films under consideration may play the role of nitric oxide depot directly in the field of pathology if they serve as implants coating.
SYNTHESIS AND PROPERTIES OF BORON-CONTAINING OLIGOMERS BASED ON HYDROQUINONE AND BORIC ACID
Authors: Lenskiy Maxim A. , Novitskiy Alexey N. , Korabel'nikov Dmitriy V. , Ozhogin Andrei V. , Shul'ts Elvira E.
Published: May 2020

By polyesterification of boric acid with hydroquinone in o-xylene with azeotropic distillation of water, polyesters of hydroquinone and boric acid are obtained. By adding equimolar amounts of phenol to the reaction between boric acid and hydroquinone, a mixed polyester of hydroquinone, phenol and boric acid is obtained. From the ratio of the integral intensity of phenol protons to hydroquinone protons, it was found that the addition of phenol to the hydroquinone polydiester and boric acid occurs by 80%. The synthesized polyesters reacted with formaldehyde using o-xylene as a solvent and a boron trifluoride etherate catalyst. By the method of end groups it was determined that all the compounds obtained have a small molecular weight and belong to the class of oligomers. The structure of the synthesized oligomers was confirmed by elemental analysis, IR and NMR (1H, 13C) spectroscopy. All compounds obtained have a good adhesion to glass, wood and metal. The thermal destruction of samples in a flow of nitrogen at 900 °C was studied, the residual mass for polyesters is from 49 to 53%, for polymethylene ester - from 18.5 to 31%. The residual mass during thermo-oxidative degradation in an air flow at 600 ° C for polyesters is from 62 to 65%, for polymethylene ester from 37 to 44%. The reaction of the modification of synthesized oligomers with a sulfur curing system and epoxy resin was studied. The maximum content of insoluble gel fraction when cured by sulfuric system at a temperature of 220 °C reaches 94% for polymethylene diester hydroquinone and boric acid, the minimum is 68% for the polytriester of hydroquinone and boric acid. The maximum content of insoluble gel fraction when cured with epoxy resin at a temperature of 150 °C for polyesters is in the range 52 - 66 %, for polymethylene ester 50 - 61%.
HYDROGEN ROLE IN SELECTIVITY OF SUBSTITUTED NITRO-AZOBENENES HYDROGENI-ZATION ON SKELETAL NICKEL IN 2-PROPANOL AQUEOUS SOLUTIONS
Authors: Lefedova Olga V. , Anh Hoang , Filippov Dmitriy V.
Published: May 2020

Elucidation of the substituted nitrobenzenes transformations sequence, in particular, containing several reactive groups and the development of approaches to the control of the selectivity of processes involving them is of interest from both theoretical and practical points of view. The article is devoted to the analysis of the hydrogenation kinetics of 2-nitro-2'-hydroxy-5'-methylazobenzene, 4-nitro-2'-hydroxy-5'-methyl-isobenzene, 4-nitroaniline, 4-amino-2'-hydroxy-5'-methylazobenzene on skeletal nickel in 2-propanol aqueous solutions of different composition, including with the addition of acetic acid or sodium hydroxide with various initial amounts of organic compound. The rise in the 4-nitro-2'-hydroxy-5'-methylazobenzene initial amount leads to increase in the nitro group transformation rate in the starting compound and to decrease in the azo-group transformation rate. The effect of sodium hydroxide additives in the 2-propanol aqueous solution on the nitro- and azo-groups conversion rate into 4-nitro-2'-hydroxy-5'-methyl-isobenzene is analogous to the change in the individual compounds hydrogenation rates (4-nitroaniline and 4-amino-2'-hydroxy-5'-methylazobenzene). Obtained results do not contradict the parallel-sequential scheme concept for the 4-nitro-2'-hydroxy-5'-methylazobenzene transformations. One of the directions is associated with the azo-group transformation into 4-nitro-2'-hydroxy-5'-methylazobenzene and 4-nitroaniline and 2-amino-4-methylphenol formation, and the second with the 4-nitro-2'-hydroxy-5'-methyl-isobenzene conversion through 4-amino-2'-hydroxy-5'-methyl-isobenzene by the nitro-group reducing. At the reaction end, all intermediate compounds are reduced to 2-amino-4-methylphenol and 1,4-phenylenediamine. When 2-nitro-2'-hydroxy-5'-methylazobenzene is hydrogenated, one of the directions leads to the 2-nitro-2'-hydroxy-5'-methylhydrazobenzene formation, and the second to the product containing the triazole cycle - N-oxide 2-2'-hydroxy-5'-methylphenylbenzotriazole. At the reaction end, these compounds are reduced to 2-2'-hydroxy-5'-methylphenylbenzotriazole and 2-amino-4-methylphenol and 1,2-phenylenediamine, respectively. In the solution at the sodium hydroxide presence, 2-nitro-2'-hydroxy-5'-methylhydrazobenzene transforms into the N-oxide 2-2'-hydroxy-5'-methylphenylbenzotriazole as a result of intramolecular rearrangement.
PARAMETERS CRYSTALLIZATION PROCESSES AND SOLID PETROLEUM HYDROCARBONS DISSOLUTION
Authors: Gurov Yuri P. , Zemlianskii Evgeny О. , Mozyrev Andrey G. , Agaev Slavik G.
Published: May 2020

In the proposed work, the experimental data on the processes of crystallization and different nature waxy hydrocarbons recrystallization in hydrocarbon solvents have been compared. T-1 technical paraffin (GOST 23683-89) with the melting point of 54 °С and ceresin-80 (GOST 2488-79) with the dropping temperature of 80 °C have been used. РТ-1 kerosene (GOST 10227-86) and de-waxed oil of fraction 420-490 °С have been used as hydrocarbon solvents. The experimental data on crystallization and recrystallization processes of paraffin wax with a melting temperature of 54 ºC and ceresin with a dropping temperature of 80 °C in kerosene and dewaxed oil are presented in this paper. It is shown that chemical structure has the main influence on the processes of crystallization and recrystallization of solid petroleum hydrocarbons. An exceedance of solid hydrocarbons solution temperatures tр above their cloud points tп has been observed which is explained by hysteretic processes. The temperature difference Δt = tр- tп depends on the solid hydrocarbons nature and their content in solvents. Wax solutions in kerosene have higher values Δt relative to ceresin solutions in kerosene, which can be explained by the difference in chemical structure of solid hydrocarbons. With the increase in solid hydrocarbons content in their solvents due to the differences in solid hydrocarbons diffusion rate, Δt decreases. The discovered regularities of solid hydrocarbons crystallization and recrystallization should be taken into account in the processes of paraffin oil production, transportation and processing.
The Neo-Gothic Imaginary and the Rhetoric of Loss in Colson Whitehead’s The Underground Railroad
Authors: Antoszek Patrycja
Published: May 2020

The aim of my paper will be to discuss the African-American reworking of the Gothic tradition in Colson Whitehead’s neo-slave narrative. I want to argue that the figure of the protagonist Cora may be seen as the embodiment of losses that span over generations of black women. Cora’s melancholia is a strategy of dealing with the horrors of slavery and a sign of a black woman’s failed entry into the Symbolic. While the novel’s narrative technique is a symbol of the ever-present past that haunts black subjectivity, the underground railroad may be read as a metaphor for the repressed content of American national unconscious.
AMPAR/TARP stoichiometry differentially modulates channel properties
Authors: Miguez-Cabello Federico , Sánchez-Fernández Nuria , Yefimenko Natalia , Gasull Xavier , Gratacòs-Batlle Esther , Soto David
Published: May 2020

AMPARs control fast synaptic communication between neurons and their function relies on auxiliary subunits, which importantly modulate channel properties. Although it has been suggested that AMPARs can bind to TARPs with variable stoichiometry, little is known about the effect that this stoichiometry exerts on certain AMPAR properties. Here we have found that AMPARs show a clear stoichiometry-dependent modulation by the prototypical TARP γ2 although the receptor still needs to be fully saturated with γ2 to show some typical TARP-induced characteristics (i.e. an increase in channel conductance). We also uncovered important differences in the stoichiometric modulation between calcium-permeable and calcium-impermeable AMPARs. Moreover, in heteromeric AMPARs, γ2 positioning in the complex is important to exert certain TARP-dependent features. Finally, by comparing data from recombinant receptors with endogenous AMPAR currents from mouse cerebellar granule cells, we have determined a likely presence of two γ2 molecules at somatic receptors in this cell type.
HIV efficiently infects T cells from the endometrium and remodels them to promote systemic viral spread
Authors: Ma Tongcui , Luo Xiaoyu , George Ashley F , Mukherjee Gourab , Sen Nandini , Spitzer Trimble L , Giudice Linda C , Greene Warner C , Roan Nadia R
Published: May 2020

The female reproductive tract (FRT) is the most common site of infection during HIV transmission to women, but viral remodeling complicates characterization of cells targeted for infection. Here, we report extensive phenotypic analyses of HIV-infected endometrial cells by CyTOF, and use a ‘nearest neighbor’ bioinformatics approach to trace cells to their original pre-infection phenotypes. Like in blood, HIV preferentially targets memory CD4+ T cells in the endometrium, but these cells exhibit unique phenotypes and sustain much higher levels of infection. Genital cell remodeling by HIV includes downregulating TCR complex components and modulating chemokine receptor expression to promote dissemination of infected cells to lymphoid follicles. HIV also upregulates the anti-apoptotic protein BIRC5, which when blocked promotes death of infected endometrial cells. These results suggest that HIV remodels genital T cells to prolong viability and promote viral dissemination and that interfering with these processes might reduce the likelihood of systemic viral spread.
Diverse homeostatic and immunomodulatory roles of immune cells in the developing mouse lung at single cell resolution
Authors: Domingo-Gonzalez Racquel , Zanini Fabio , Che Xibing , Liu Min , Jones Robert C , Swift Michael A , Quake Stephen R , Cornfield David N , Alvira Cristina M
Published: May 2020

At birth, the lungs rapidly transition from a pathogen-free, hypoxic environment to a pathogen-rich, rhythmically distended air-liquid interface. Although many studies have focused on the adult lung, the perinatal lung remains unexplored. Here, we present an atlas of the murine lung immune compartment during early postnatal development. We show that the late embryonic lung is dominated by specialized proliferative macrophages with a surprising physical interaction with the developing vasculature. These macrophages disappear after birth and are replaced by a dynamic mixture of macrophage subtypes, dendritic cells, granulocytes, and lymphocytes. Detailed characterization of macrophage diversity revealed an orchestration of distinct subpopulations across postnatal development to fill context-specific functions in tissue remodeling, angiogenesis, and immunity. These data both broaden the putative roles for immune cells in the developing lung and provide a framework for understanding how external insults alter immune cell phenotype during a period of rapid lung growth and heightened vulnerability.
Signaling diversity enabled by Rap1-regulated plasma membrane ERK with distinct temporal dynamics
Authors: Keyes Jeremiah , Ganesan Ambhighainath , Molinar-Inglis Olivia , Hamidzadeh Archer , Zhang Jinfan , Ling Megan , Trejo JoAnn , Levchenko Andre , Zhang Jin
Published: May 2020

A variety of different signals induce specific responses through a common, extracellular-signal regulated kinase (ERK)-dependent cascade. It has been suggested that signaling specificity can be achieved through precise temporal regulation of ERK activity. Given the wide distrubtion of ERK susbtrates across different subcellular compartments, it is important to understand how ERK activity is temporally regulated at specific subcellular locations. To address this question, we have expanded the toolbox of Förster Resonance Energy Transfer (FRET)-based ERK biosensors by creating a series of improved biosensors targeted to various subcellular regions via sequence specific motifs to measure spatiotemporal changes in ERK activity. Using these sensors, we showed that EGF induces sustained ERK activity near the plasma membrane in sharp contrast to the transient activity observed in the cytoplasm and nucleus. Furthermore, EGF-induced plasma membrane ERK activity involves Rap1, a noncanonical activator, and controls cell morphology and EGF-induced membrane protrusion dynamics. Our work strongly supports that spatial and temporal regulation of ERK activity is integrated to control signaling specificity from a single extracellular signal to multiple cellular processes.
A molecular filter for the cnidarian stinging response
Authors: Weir Keiko , Dupre Christophe , van Giesen Lena , Lee Amy S-Y , Bellono Nicholas W
Published: May 2020

All animals detect and integrate diverse environmental signals to mediate behavior. Cnidarians, including jellyfish and sea anemones, both detect and capture prey using stinging cells called nematocytes which fire a venom-covered barb via an unknown triggering mechanism. Here, we show that nematocytes from Nematostella vectensis use a specialized voltage-gated calcium channel (nCaV) to distinguish salient sensory cues and control the explosive discharge response. Adaptations in nCaV confer unusually sensitive, voltage-dependent inactivation to inhibit responses to non-prey signals, such as mechanical water turbulence. Prey-derived chemosensory signals are synaptically transmitted to acutely relieve nCaV inactivation, enabling mechanosensitive-triggered predatory attack. These findings reveal a molecular basis for the cnidarian stinging response and highlight general principles by which single proteins integrate diverse signals to elicit discrete animal behaviors.
TANGO1 membrane helices create a lipid diffusion barrier at curved membranes
Authors: Raote Ishier , Ernst Andreas M , Campelo Felix , Rothman James E , Pincet Frederic , Malhotra Vivek
Published: May 2020

We have previously shown TANGO1 organises membranes at the interface of the endoplasmic reticulum (ER) and ERGIC/Golgi (Raote et al., 2018). TANGO1 corrals retrograde membranes at ER exit sites to create an export conduit. Here the retrograde membrane is, in itself, an anterograde carrier. This mode of forward transport necessitates a mechanism to prevent membrane mixing between ER and the retrograde membrane. TANGO1 has an unusual membrane helix organisation, composed of one membrane-spanning helix (TM) and another that penetrates the inner leaflet (IM). We have reconstituted these membrane helices in model membranes and shown that TM and IM together reduce the flow of lipids at a region of defined shape. We have also shown that the helices align TANGO1 around an ER exit site. We suggest this is a mechanism to prevent membrane mixing during TANGO1-mediated transfer of bulky secretory cargos from the ER to the ERGIC/Golgi via a tunnel.
How HIV exploits T cells in the endometrium
Authors: Rodriguez-Garcia Marta
Published: May 2020

Immune cells in the endometrium are targeted by HIV and re-programmed to allow them to survive and spread the virus throughout the body.
Microbiome analysis of healthy and diseased sponges Lubomirskia baicalensis by using cell cultures of primmorphs
Authors: Chernogor Lubov , Klimenko Elizaveta , Khanaev Igor , Belikov Sergei
Published: May 2020

Endemic sponges (Demosponges, Lubomirskiidae) dominate the fauna of the littoral zone of Lake Baikal. These freshwater sponges live in symbiosis with diverse eukaryotes and prokaryotes, including chlorophyll-containing microalgae. Within the last 5 years, the incidence of sponge disease and mortality events in Lake Baikal has increased. The etiology and ecology of these events remain unknown, in part because of the lack of models to study sponge-microbe interactions. In this work, we tested the use of primmorph cell cultures of Lubomirskia baicalensis as a tool for investigating the microbiomes of sponges. We infected primmorphs, cultured in vitro, with samples from diseased sponges and observed, by microscopy, disease symptoms, including loss of green symbionts, associated with mass die-off events. Subsequent sequencing of 16S rRNA gene fragments revealed that the microbiome community of healthy sponge and primmorphs formed a group separate from the community of diseased sponges and infected primmorphs. This confirms the suitability of the primmorph cell culture as a model sponge system. We also discovered mass mortality of green symbionts (Chlorophyta) was associated with a shift in the microbial communities of sponges/primmorphs. Microbes in diseased sponges, and infected primmorphs, belonged mainly to the phyla Bacteroidetes and Proteobacteria and these families Flavobacteriaceae, Burkholderiaceae, and Moraxellaceae. Primmorphs cell culture may provide a model to study interactions between these bacteria and their host and elucidate the cause of mass mortality events.
Cca-miR398 increases copper sulfate stress sensitivity via the regulation of CSD mRNA transcription levels in transgenic Arabidopsis thaliana
Authors: Sun Zhichao , Shu Lilu , Zhang Wei , Wang Zhengjia
Published: May 2020

MicroRNAs play crucial roles during the process of plant development under stress conditions. Copper is an essential micronutrient for most organisms and serves as an important redox-active cofactor for various functional proteins. In the present study, we investigated the effects of copper sulfate stress on hickory (Carya cathayensis) root development. We identified that hickory cca-miR398 was related to copper sulfate stress response, targeting Copper/Zinc superoxide dismutases (cytosolic (CSD1) and chloroplastic (CSD2)) and a 5b subunit of mitochondrial cytochrome C oxidase (COX5b.1) that are linked directly to stress regulatory networks. The sequence of hickory cca-miR398 is highly similar to that of Arabidopsis miR398b and miR398c, regardless of one nucleotide variation. Therefore, target genes of cca-miR398 were investigated by using 5′-Rapid-amplification of cDNA ends. An overexpression of cca-miR398 in Arabidopsis caused a reduction not only in root length and cotyledon greening, but also in the CSD1, CSD2, and CSD3 transcription levels. These reductions had greater significance in transgenic Arabidopsis than in wild-type Arabidopsis under copper sulfate stress. The level of physiological indicators also changed in transgenic Arabidopsis. In addition, the expressions of copper-responsive microRNAs, such as miR397 and miR408, were affected by the copper sulfate stress. These results showed that CSD possesses the ability to enhance copper sulfate stress response in both transgenic Arabidopsis and hickory roots by increasing the production of superoxide dismutase. Our results also demonstrated that cca-miR398 weakens hickory tolerance to copper sulfate by regulating CSD targets.
At the crossroads of botanical collections and molecular genetics laboratory: a preliminary study of obtaining amplifiable DNA from moss herbarium material
Authors: Saługa Marta
Published: May 2020

Background

Research focused on extreme environments is often associated with difficulties in obtaining fresh plant material. Herbaria may provide great support as they house large collections of specimens from different parts of the world. Accordingly, there is also a growing interest in methods using herbarium specimens in molecular studies. Much of the literature on herbarium DNA is aimed to improve extraction and PCR amplification and is focused mostly on vascular plants. Here, I provide a brief study of DNA extraction efficiency from moss herbarium specimens, emphasizing the importance of herbaria as an invaluable source of material from hard-to-access geographical areas, such as the Antarctic region.

Methods

The presented study is based on herbarium collections of 25 moss species collected in the austral polar regions between 1979 and 2013. The majority of samples were obtained using the DNeasy Plant Mini Kit (Qiagen, Hilden, Germany). The remaining, smaller part was extracted using an adapted CTAB-based approach. The performance of DNA extraction methods in terms of PCR amplification success was measured by testing several DNA fragments of various size. Furthermore, in order to estimate of DNA fragmentation level, an automated on-chip electrophoresis system was used.

Results

Results reveal that DNA purity and the length of the target genetic region are the fundamental agents which drive the successful PCR reaction. Conversely, the DNA yield and specimen age seem to be less relevant. With this study, I present also an optimized CTAB-based approach which may effectively suppress inhibitors in the herbarium DNA. This method can be considered a cheaper alternative to column-based technology, particularly useful for dealing with a large number of samples. Results of this study confirmed previous reports and contribute to filling the existing gap in molecular analyses which involve the use of herbarium collections of mosses.
A new nematode species, Chromadorina tangaroa sp. nov. (Chromadorida: Chromadoridae) from the hull of a research vessel, New Zealand
Authors: Leduc Daniel
Published: May 2020

Chromadorina is a globally distributed, largely marine nematode genus frequently found on a variety of organisms, including macro- and microalgae and crustaceans, as well as artificial substrates such as settlement plates and ship hulls. Here, Chromadorina tangaroa sp. nov. is described from filamentous seaweed growing on the hull of RV Tangaroa anchored in Wellington, North Island of New Zealand. It is characterized by body length 763–1,086 μm, and pore of secretory-excretory system located at or near level of teeth. Males have spicules with rounded capitulum followed by a narrower shaft and blade tapered distally, a gubernaculum as long as the spicules, and three cup-shaped precloacal supplements, and females are characterized by a cuticularized prevulvar pad, vagina located at 46–48% of body length from anterior, and vagina anteriorly directed. Chromadorina tangaroa sp. nov. is the first species of the genus to be described from New Zealand, but it is unclear whether it is native to the region because it may have dispersed as part of ship hull biofouling communities. Long-distance transport of nematodes through ship hull biofouling may be a common occurrence, but too little is known about the occurrence of nematodes on ship hulls to gauge the potential effect of shipping on nematode species distributions.
Demonstration of Maize-Nougcake Concentrate Based Sheep Fattening in Horro District, Oromia Regional State, Ethiopia
Authors: Soboka Berhanu , Wolteji Effa , Gedefa Bayisa
Published: May 2020

This activity was conducted in Horro district of western Oromia, Ethiopia with the objective of popularizing proven sheep fattening technology. The study sites were Leku and Gitilo kebeles where community based sheep breeding project is underway. The rams to be fattened were weighed; body condition was recorded, de-wormed and sprayed against internal and external parasites. Initial price of the rams was estimated by a panel of three price informed estimators. The rams were supplemented with 400 g/h/day concentrate composed of 49.5% Noug cake, 49.5% ground maize, 1% salt for 90 days fattening period. The mean initial weight, final weight, initial price and selling prices of the rams were 21.05 kg, 28.51 kg, 517 birr and 1577.5 birr, respectively. Total body weight gain (TWG) of the rams on average was 7.5 kg over the fattening period with a range of 4.5-13.5 kg. The average daily gain (ADG) for the fattening period was 83.3 g/h/ day. The difference between initial and final body weight (7.5 kg) and initial and final body condition (1.7 kg) were statistically significant (p=0.00) and (p=.04), respectively. On average, a net return of birr 456.7 was accrued to the farmers from sale of the fattened rams. An increase in input price by 10%, keeping the price of fattened rams constant would result in marginal return of 1.6 and a net return of 396 birr. The technology is still profitable on the face of the expected escalation in input prices. The escalation is counteracted by the current attractive sale price of fattened rams. It is thus important to go for further scaling up in areas where there is access to these inputs.
Efficacy of Three Botanicals in Cowpea Field, Oyo State, Nigeria
Authors: Isienyi N. C. , Fadina O. O. , Fayinminnu O. O. , Olubode O. S.
Published: May 2020

Aims: To evaluate the effects of different concentrations of the plant extracts of Eucalyptus camaldulensis (EU), Eucalyptus torreliana (ET) and Leucaena leucocephala (LL) on seed-germination, seedling-growth, weed flora and yield performance of cowpea.

Study Design: The study was laid out in a completely randomized design (CRD) with eighteen ttreatments replicated three (3) times, totaling fifty-four (54) experimental samples. The whole experiments were repeated in two trials.

Place and Duration of the Study: This study was carried out on the roof top garden of department of Crop Protection and Environmental Biology, University of Ibadan, Nigeria from 2015 to 2017.

Methodology: Leaves of EU, ET and LL were harvested, air-dried, milled and assayed for phytochemicals (mg/g) following standard-procedures. Milled samples (144, 108, 72, 36 and 0 g) of each botanical were dissolved in 1 L distilled-water to obtain Aqueous-Leaf-Extracts (ALE) of 100, 75, 50, 25 and 0% (control) concentrations. Ten seeds of cowpea-Ife brown in petri dishes were treated with the different concentrations. Data were collected on Seed Germination-SG (%). In pots containing 10 kg soil, cowpea-seeds (2 plants/pot) were sown. Each botanical-extract at different concentrations and paraquat (5 mL/L/ha) were applied, before and five Weeks-After-Sowing (WAS). Data were collected on Plant height-PH (cm) at 3,5,7,9 and 11 WAS, while Grain Yield-GY (g/pot) was determined at maturity. Relative Importance Values (RIVs) were determined following standard-procedures. Data were analysed with descriptive-statistics and ANOVA at α0.05.

Results: Total phenols (32.04±0.10), tannins (27.40±0.04) and saponins (20.15±0.03) were significantly higher in EU than in ET and LL. Cowpea SG ranged from 80.0±0.5 (50% LL) to 100.0±1.2 (100% LL). Cowpea PH ranged from 18.2±2.0 (100% ET) to 48.5±3.2 (100% EU) both at 9-WAS. Cowpea GY ranged from 0.1±0.1 (25% LL) to 4.2±0.5 (50% LL). Mitracarpus villosus had highest RIV of 52.3 (100% EU at 3-WAS) but reduced to 28.5 (100% EU at 9-WAS). Aqueous-leaf-extract of Eucalyptus camaldulensis at 100% reduced Mitracarpus villosus populations, while Leucaena leucocephala at 50% improved grain yields.
Review of Pathogenesis of COVID-19: Considerations
Authors: Stanley C. N. , Ayodeji O. A. , Stanley P. C.
Published: May 2020

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with a primary target on the human respiratory system. Coronavirus disease was first discovered in Wuhan, China in December 2019 and has currently become a global pandemic. A lot is still unknown about COVID -19 pathogenesis. Prompt assessment, adequate follow up, test and retest of recovered cases to corroborate immune related considerations will go a long way to understand the pathogenesis.