490 research outputs found

    Propriedades Texturais dos Sedimentos Litorâneos de Santa Catarina. III - Trecho Laguna-Araranguá

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    Areias praiais e de dunas, do trecho Laguna-Araranguá, no litoral de Santa Catarina, foram analisadas com a finalidade de obtenção dos característicos texturais mais salientes destes dois tipos de depósitos. Cento e duas amostras foram coletadas, numa faixa litorânea de aproximadamente 120 quilômetros, apresentando as seguintes propriedades: Areias praiais: diâmetro mediano e médio entre 2-3 Ø (areia fina) bem selecionada, (desvio padrão σI entre 0,35-0,50) assimetria negativa meso-leptocúrticas, grãos bem arredondados e textura superficial mamelonada polida. Areias de dunas: diâmetro mediano e médio entre 2-3 Ø (areia fina) muito bem selecionada (σ < 0,35) assimetria positiva e plati-mesocúrticas, grãos arredondados e textura mamelonada polida predominando sobre a fosca. Diagramas dispersos revelaram ser a assimetria e o desvio padrão os parâmetros texturais mais diagnósticos para diferenciação dos dois tipos de mecânica deposicional na área

    Sedimentos Relíquias na Plataforma Continental Brasileira

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    O estudo de sedimentos relíquias, ocorrentes em plataforma continental, tem contribuído para a compreensão de sua evolução paleogeográfica Quaternária e para o desenvolvimento de trabalhos de caráter econômico e aplicado. Na plataforma continental Brasileira, os estudos realizados, permitiram sua identificação, mapeamento e conhecimento de suas propriedades mecânicas e mineralógicas, bem como a identificação da morfologia de fundo associada. Indícios de sua evolução, especialmente ligados a posições de níveis de mar pretéritos, bem como a indicação de recursos econômicos associado aos sedimentos superficiais, têm sido revelados

    Novel pharmacological actions of Trequinsin Hydrochloride improve human sperm cell motility and function

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    Background and purposeAsthenozoospermia is a leading cause of male infertility, but the development of pharmaceuticals to improve sperm motility has been hindered by the lack of effective screening platforms and knowledge of suitable molecular targets. We have demonstrated that a high throughput screening (HTS) strategy in conjunction with established in vitro tests can identify and characterise the action of compounds that improve sperm motility. The study aimed to apply HTS to identify new compounds from a novel small molecule library that increase intracellular calcium, [Ca2+]I, promote human sperm cell motility and systemically determine the mechanism of action. Experimental approach A validated HTS fluorometric [Ca2+]i assay was used to screen an in-house library of compounds. Trequinsin hydrochloride (a phosphodiesterase 3 inhibitor) was selected for detailed molecular (plate reader assays, electrophysiology and cyclic nucleotide measurement) and functional (motility and acrosome reaction) testing in sperm from healthy volunteer donors and, where possible, patients.   Key resultsThe fluorometric analysis identified Trequinsin as an efficacious agonist of [Ca2+]i, although less potent than progesterone (P4). Functionally, Trequinsin significantly increased cell hyperactivation and penetration into viscous medium in all donor sperm samples and cell hyperactivation in 22/25 (88%) patient sperm samples. The Trequinsin-induced [Ca2+]i response was cross-desensitised consistently by prostaglandin E1 but not with P4. Whole-cell patch clamp electrophysiology confirmed that Trequinsin activates CatSper and partially inhibits potassium channel activity. Trequinsin also increases intracellular cGMP.   Conclusion and Implications Trequinsin exhibits a novel pharmacological profile in human sperm and may be a suitable lead compound for the development of new pharmaceuticals to improve patient sperm function and fertilisation potential

    Morfologia e Sedimentos da Plataforma Continental Leste Brasileira

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    Um reconhecimento preliminar na plataforma continental brasileira, entre Cabo Frio e Aracaju, revelou a existência de três fácies fundamentais no recobrimento sedimentar de fundo. A contribuição terrígena está representada por areias e lamas situadas próximas à linha de praia e de desenvolvimento pouco expressivo a não ser nas vizinhanças de rios com drenagem ampla. Areias carbonáticas biodetríticas e nódulos de algas calcárias gradacionam em direção a mar aberto para um fundo biogênico constituído por formas coloniais predominantemente algalicas, localizado na zona mais externa da plataforma. Sob o ponto de vista morfológico, perfis efetuados normais à costa, revelaram irregularidades da ordem de 20-30 metros, oscilando as profundidades na altura de quebra da plataforma em torno de 70 metros. Vários alinhamentos de montes submarinos foram identificados na altura da elevação continental

    Complex CatSper-dependent and independent [Ca2<sup>+</sup>]i signalling in human spermatozoa induced by follicular fluid

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    STUDY QUESTION: Does progesterone in human follicular fluid (hFF) activate CatSper and do other components of hFF modulate this effect and/or contribute separately to hFF-induced Ca2+ signaling?SUMMARY ANSWER: hFF potently stimulates CatSper and increases [Ca2+]i, primarily due to high concentrations of progesterone, however,other components of hFF also contribute to [Ca2+]i signaling, including modulation of CatSper channel activity and inhibition of [Ca2+]i oscillations.WHAT IS KNOWN ALREADY: CatSper, the principal Ca2+ channel in spermatozoa, is progesterone-sensitive and essential for fertility. Both hFF and progesterone, which is present in hFF, influence sperm function and increase their [Ca2+]i.STUDY DESIGN, SIZE, DURATION: This basic medical research study used semen samples from &gt;40 donors and hFF from &gt;50 patients who were undergoing surgical oocyte retrieval for IVF/ICSI.PARTICIPANTS/MATERIALS, SETTING, METHODS: Semen donors and patients were recruited in accordance with local ethics approval (13/ES/0091) from the East of Scotland Research Ethics Service REC1. Activities of CatSper and KSper were assessed by patch clamp electrophysiology. Sperm [Ca2+]i responses were examined in sperm populations and single cells. Computer-assisted sperm analysis (CASA) parameters and penetration into viscous media were used to assess functional effects.MAIN RESULTS AND THE ROLE OF CHANCE: hFF and progesterone significantly potentiated CatSper currents. Under quasiphysiologicalconditions, hFF (up to 50%) failed to alter membrane K+ conductance or current reversal potential. hFF and progesterone (at an equivalent concentration) stimulated similar biphasic [Ca2+]i signals both in sperm populations and single cells. At a high hFF concentration (10%), the sustained (plateau) component of the [Ca2+]i signal was consistently greater than that induced by progesterone alone. In single cell recordings, 1% hFF-induced [Ca2+]i oscillations similarly to progesterone but with 10% hFF generation of [Ca2+]i oscillations was suppressed. After treatment to ‘strip’ lipid-derived mediators, hFF failed to significantly stimulate CatSper currents but induced small [Ca2+]i responsesthat were greater than those induced by the equivalent concentration of progesterone after stripping. Similar [Ca2+]i responses were observed when sperm pretreated with 3 μM progesterone (to desensitize progesterone responses) were stimulated with hFF or stripped hFF. hFF stimulated viscous media penetration and was more effective than the equivalent does of progesterone.LARGE SCALE DATA: N/A.LIMITATIONS, REASONS FOR CAUTION: This was an in vitro study. Caution must be taken when extrapolating these results in vivo.WIDER IMPLICATIONS OF THE FINDINGS: This study directly demonstrates that hFF activates CatSper and establishes that the biologically important effects of hFF reflect, at least in part, action on this channel, primarily via progesterone. However, these experiments also demonstrate that other components of hFF both contribute to the [Ca2+]i signal and modulate the activation of CatSper. Simple in vitro experiments performed out of the context of the complex in vivo environment need to be interpreted with caution

    Misturas Populacionais e Efetividades de Energia Ambiental

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    Relations between grain size properties and energy level of ocean beaches of coastal zone of the State of Santa Catarina. High-energy beaches prodice unimodal, wellsorted sands with few testural classe. Low-energy beaches produce poorly sorted, sometimes bimodal sands, with a large number of textural classes. Changes in unipopulational or bipopulational sedimentes in a low or high energy environment are also presented.São apresentadas as relações existentes entre as propriedades de tamanho de sedimentos praiais oceânicos e os diferentes níveis de energia presentes em várias praias do litoral de Santa Catarina. Areias ativadas por índices elevados de energia, são unimodais, bem selecionadas, apresentando pequeno número de classes texturais. Níveis pouco expressivos de energia revelam areias mal selecionadas, por vezes bimodais e apresentando elevado número de classes texturais. Variações entre sedimentos uni ou bipolucionais são igualmente comentadas

    Single-cell analysis of [Ca<sup>2+</sup>]i signalling in sub-fertile men:characteristics and relation to fertilization outcome

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    STUDY QUESTIONWhat are the characteristics of progesterone-induced (CatSper-mediated) single cell [Ca2+]i signals in spermatozoa from sub-fertile men and how do they relate to fertilizing ability?SUMMARY ANSWERSingle cell analysis of progesterone-induced (CatSper-mediated) [Ca2+]i showed that reduced progesterone-sensitivity is a common feature of sperm from sub-fertile patients and is correlated with fertilization rate.WHAT IS KNOWN ALREADYStimulation with progesterone is a widely used method for assessing [Ca2+]i mobilization by activation of CatSper in human spermatozoa. Although data are limited, sperm population studies have indicated an association of poor [Ca2+]i response to progesterone with reduced fertilization ability.STUDY DESIGN, SIZE, DURATIONThis was a cohort study using semen samples from 21 donors and 101 patients attending the assisted conception unit at Ninewells Hospital Dundee who were undergoing ART treatment. Patients were recruited from January 2016 to June 2017.PARTICIPANTS/MATERIALS, SETTING, METHODSSemen donors and patients were recruited in accordance with local ethics approval (13/ES/0091) from the East of Scotland Research Ethics Service (EoSRES) REC1. [Ca2+]i responses were examined by single cell imaging and motility parameters assessed by computer-assisted sperm analysis (CASA).MAIN RESULTS AND THE ROLE OF CHANCEFor analysis, patient samples were divided into three groups IVF(+ve) (successful fertilization; 62 samples), IVF-FF (failed fertilization; eight samples) and ICSI (21 samples). A further 10 IVF samples showed large, spontaneous [Ca2+]i oscillations and responses to progesterone could not be analysed. All patient samples loaded with the [Ca2+]i-indicator fluo4 responded to progesterone stimulation with a biphasic increase in fluorescence (transient followed by plateau) which resembled that seen in progesterone-stimulated donor samples. The mean normalized response (progesterone-induced increase in fluorescence normalized to resting level) was significantly smaller in IVF-FF and ICSI patient groups than in donors. All samples were further analysed by plotting, for each cell, the relationship between resting fluorescence intensity and the progesterone-induced fluorescence increment. In donor samples these plots overlaid closely and had a gradient of ≈ 2 and plots for most IVF(+ve) samples closely resembled the donor distribution. However, in a subset (≈ 10%) of IVF(+ve) samples, 3/8 IVF-FF samples and one-third of ICSI samples the gradient of the plot was significantly lower, indicating that the response to progesterone of the cells in these samples was abnormally small. Examination of the relationship between gradient (regression coefficient of the plot) in IVF samples and fertilization rate showed a positive correlation. In IVF-FF and ICSI groups, the proportion of cells in which a response to progesterone could be detected was significantly lower than in donors and IVF (+ve) patients. Approximately 20% of cells in donor, IVF(+ve) and ICSI samples generated [Ca2+]i oscillations when challenged with progesterone but in IVF-FF samples only ≈ 10% of cells generated oscillations and there was a significantly greater proportion of samples where no oscillations were observed. Levels of hyperactivated motility were lower in IVF(+ve) and IVF-FF groups compared to controls, IVF-FF also having lower levels than IVF(+ve).LIMITATIONS, REASONS FOR CAUTIONThis is an in vitro study and caution must be taken when extrapolating these results in vivo.WIDER IMPLICATIONS OF THE FINDINGSThis study reveals important details of impaired [Ca2+]i signalling in sperm from sub-fertile men that cannot be detected in population studies

    Partially premixed flame reactive flow characterization in a bluff body burner

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    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The present work aims the characterization of a natural gas/air partially premixed flame (PPF) reactive flow in a bluff body burner under laminar conditions in equivalence ratio of 2.1, 1.7 and 1.2. The laboratorial bluff body burner is composed of a central outflow for the premixed reactants and an annular air flow. The latter allows for the stabilization of the flame meanwhile it prevents external aerodynamic influence on the behavior of the flame. For the velocity field measurements, a 2-D Particle Image Velocimetry, PIV, optical diagnostic system is employed. The PIV system comprises of two Nd:YAG lasers with an output wavelength of 532 nm. Titanium dioxide particles, TiO2, are used as seeding particles in the premixed flow. The displacement of the seeding particles between two laser pulses with a known short time difference allows a planar velocity field determination. The stored images are processed using a software integrated with the system in order to obtain the medium velocity field. The software uses statistic data to obtain the correlation between two images acquired in an interval of time of an overlapped interrogation window. The major objective of this study is to examine the flame velocity field of laminar partially premixed natural gas and air flames in rich conditions. Three premixed flames under rich conditions have been studied in the present work with equivalence ratios of 2.1, 1.7 and 1.2 respectively. The study focused on: (1) analyze the instantaneous velocity flow field of the three partially premixed flames, (2) analyze the mean velocity flow field formed from the instantaneous flow fields and (3) analyze the velocity behavior along the center line of the flame.cf201

    Efeito do ensacamento dos frutos no controle de pragas e doenças e na qualidade e maturação de maçãs ‘Fuji Suprema’.

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    O objetivo deste trabalho foi avaliar a eficiência de embalagens de diferentes materiais para a proteção contra pragas e doenças e seu efeito sobre a qualidade físico-química, maturação e teor de cálcio (Ca) em maçãs ‘Fuji Suprema’. O experimento foi desenvolvido nas safras de 2007/2008 e 2008/2009, em pomar manejado sob o sistema orgânico, localizado na região de São Joaquim (SC). O pomar era composto por plantas de dez anos de idade da cultivar Fuji Suprema, sobre porta-enxerto ‘Marubakaido’, com interenxerto ‘EM-9’. Depois do raleio manual, aproximadamente 40 dias após a plena floração, os frutos foram ensacados com embalagens plásticas transparentes microperfuradas ou de tecido não texturizado (TNT). Os frutos foram mantidos ensacados até a colheita. A testemunha foi constituída por frutos não ensacados. Na colheita, os frutos foram avaliados quanto aos danos provocados por mosca-das-frutas (Anastrepha fraterculus), mariposa oriental (Grapholita molesta) e lagarta enroladeira (Bonagota salubricola). As doenças foram avaliadas pela incidência de sarna da macieira (Venturia inaequalis), podridão amarga (Colletotrichum gloeosporioides) e podridão carpelar (Alternaria sp., Fusarium sp.). Também foi avaliada a incidência de distúrbios fisiológicos “russeting” e “bitter pit”, atributos físico-químicos de maturação e qualidade e o teor de Ca nos frutos. Independentemente do tipo de embalagem verificou-se que o ensacamento é prática eficaz na proteção contra o ataque de insetos, mas não reduz a incidência e o desenvolvimento de doenças nos frutos. Na safra de 2008/2009, o ensacamento dos frutos aumentou o teor de Ca e reduziu a incidência de “bitter pit”, e aumentou a incidência do “russeting”. O ensacamento dos frutos antecipou a maturação, especialmente com embalagem plástica transparente microperfurada, e reduziu a coloração vermelha, especialmente com embalagem TNT

    Clinically relevant enhancement of human sperm motility using compounds with reported phosphodiesterase inhibitor activity

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    STUDY QUESTION: Can we identify compound(s) with reported phosphodiesterase inhibitor (PDEI) activity that could be added to human spermatozoa in vitro to enhance their motility without compromising other sperm functions? SUMMARY ANSWER: We have identified several compounds that produce robust and effective stimulation of sperm motility and, importantly, have a positive response on patient samples. WHAT IS KNOWN ALREADY: For &gt;20 years, the use of non-selective PDEIs, such as pentoxifylline, has been known to influence the motility of human spermatozoa; however, conflicting results have been obtained. It is now clear that human sperm express several different phosphodiesterases and these are compartmentalized at different regions of the cells. By using type-specific PDEIs, differential modulation of sperm motility may be achieved without adversely affecting other functions such as the acrosome reaction (AR). STUDY DESIGN, SIZE, DURATION: This was a basic medical research study examining sperm samples from normozoospermic donors and subfertile patients attending the Assisted Conception Unit (ACU), Ninewells Hospital Dundee for diagnostic semen analysis, IVF and ICSI. Phase 1 screened 43 commercially available compounds with reported PDEI activity to identify lead compounds that stimulate sperm motility. Samples were exposed (20 min) to three concentrations (1, 10 and 100 µM) of compound, and selected candidates (n = 6) progressed to Phase 2, which provided a more comprehensive assessment using a battery of in vitro sperm function tests.  PARTICIPANTS/MATERIALS, SETTING, METHODS: All healthy donors and subfertile patients were recruited at the Medical Research Institute, University of Dundee and ACU, Ninewells Hospital Dundee (ethical approval 08/S1402/6). In Phase 1, poor motility cells recovered from the 40% interface of the discontinuous density gradient were used as surrogates for patient samples. Pooled samples from three to four different donors were utilized in order to reduce variability and increase the number of cells available for simultaneous examination of multiple compounds. During Phase 2 testing, semen samples from 23 patients attending for either routine diagnostic andrology assessment or IVF/ICSI were prepared and exposed to selected compounds. Additionally, 48 aliquots of prepared samples, surplus to clinical use, were examined from IVF (n = 32) and ICSI (n = 16) patients to further determine the effects of selected compounds under clinical conditions of treatment. Effects of compounds on sperm motility were assessed by computer-assisted sperm analysis. A modified Kremer test using methyl cellulose was used to assess sperm functional ability to penetrate into viscous media. Sperm acrosome integrity and induction of apoptosis were assessed using the acrosomal content marker PSA-FITC and annexin V kit, respectively. MAIN RESULTS AND THE ROLE OF CHANCE: In Phase 1, six compounds were found to have a strong effect on poor motility samples with a magnitude of response of ≥60% increase in percentage total motility. Under capacitating and non-capacitating conditions, these compounds significantly (P ≤ 0.05) increased the percentage of total and progressive motility. Furthermore, these compounds enhanced penetration into a cervical mucus substitute (P ≤ 0.05). Finally, the AR was not significantly induced and these compounds did not significantly increase the externalization of phosphatidylserine (P = 0.6, respectively). In general, the six compounds maintained the stimulation of motility over long periods of time (180 min) and their effects were still observed after their removal. In examinations of clinical samples, there was a general observation of a more significant stimulation of sperm motility in samples with lower baseline motility. In ICSI samples, compounds #26, #37 and #38 were the most effective at significantly increasing total motility (88, 81 and 79% of samples, respectively) and progressive motility (94, 93 and 81% of samples, respectively). In conclusion, using a two-phased drug discovery screening approach including the examination of clinical samples, 3/43 compounds were identified as promising candidates for further study. LIMITATIONS, REASONS FOR CAUTION: This is an in vitro study and caution must be taken when extrapolating the results. Data for patients were from one assessment and thus the robustness of responses needs to be established. The n values for ICSI samples were relatively small. WIDER IMPLICATIONS OF THE FINDINGS: We have systematically screened and identified several compounds that have robust and effective stimulation (i.e. functional significance with longevity and no toxicity) of total and progressive motility under clinical conditions of treatment. These compounds could be clinical candidates with possibilities in terms of assisted reproductive technology options for current or future patients affected by asthenozoospermia or oligoasthenozoospermia
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