8,181 research outputs found

    Estratégias para reduzir a mortalidade embrionária em bovinos: II. Protocolo para reduzir a mortalidade embrionária em vacas de leite e em receptoras de embrião.

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    A mortalidade embrionária precoce é a maior causa de perdas reprodutivas em bovinos e ela relaciona-se, principalmente com os distúrbios do reconhecimento materno da prenhez originados em disfunções do corpo lúteo ovariano. Recentemente, foi desenvolvido na Embrapa Pecuária Sudeste, um protocolo hormonal que melhora a função luteínica e permite aumentar a oportunidade para um reconhecimento materno da prenhez bem sucedido. O protocolo baseia-se na administração de hormônios reprodutivos (GnRH e hCG) em ocasiões estratégicas após a ovulação. Foram realizados dois experimentos, um com vacas leiteiras e outro com receptoras de embrião, para testar e validar o uso desse protocolo. Após a aplicação do tratamento houve aumento nas taxas de prenhez. Os resultados detalhados do uso dessa prática estão descritos no presente Boletim de Pesquisa e Desenvolvimento. O protocolo testado traduz-se numa prática pecuária de controle das funções ovariana e uterina que otimiza a eficiência reprodutiva de vacas leiteiras e de receptoras de embrião.bitstream/item/43513/1/Boletim27.pd

    Biosurfactants produced by Bacillus subtilis A1 and Pseudomonas stutzeri NA3 reduce longevity and fecundity of Anopheles stephensi and show high toxicity against young instars

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    Anopheles stephensi acts as vector of Plasmodium parasites, which are responsible for malaria in tropical and subtropical areas worldwide. Currently, malaria management is a big challenge due to the presence of insecticide-resistant strains as well as to the development of Plasmodium species highly resistant to major antimalarial drugs. Therefore, the present study focused on biosurfactant produced by two bacteria Bacillus subtilis A1 and Pseudomonas stutzeri NA3, evaluating them for insecticidal applications against malaria mosquitoes. The produced biosurfactants were characterized using FT-IR spectroscopy and gas chromatography-mass spectrometry (GC-MS), which confirmed that biosurfactants had a lipopeptidic nature. Both biosurfactants were tested against larvae and pupae of A. stephensi. LC50 values were 3.58 (larva I), 4.92 (II), 5.73 (III), 7.10 (IV), and 7.99 (pupae) and 2.61 (I), 3.68 (II), 4.48 (III), 5.55 (IV), and 6.99 (pupa) for biosurfactants produced by B. subtilis A1 and P. stutzeri NA3, respectively. Treatments with bacterial surfactants led to various physiological changes including longer pupal duration, shorter adult oviposition period, and reduced longevity and fecundity. To the best of our knowledge, there are really limited reports on the mosquitocidal and physiological effects due to biosurfactant produced by bacterial strains. Overall, the toxic activity of these biosurfactant on all young instars of A. stephensi, as well as their major impact on adult longevity and fecundity, allows their further consideration for the development of insecticides in the fight against malaria mosquitoes

    effectiveness of aquatic therapy in post-surgery rehabilitation of the rotator cuff

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    Introduction: rotator cuff injuries very often require surgical repair and subsequent rehabilitation. The aim of this study was to compare the effectiveness of a traditional and an aquatic post-surgery rehabilitation program of the rotator cuff in 20 adult (60±5y) patients. Methods:patients were randomly assigned to a traditional (TR; n=10) and to an aquatic (WR; n=10) rehabilitation group. Both programs started 15 days after the surgery, lasted 3 months (3 times-a-week), and consisted in passive mobilization followed by strengthening exercises. The only WR group underwent to an adjunctive aquatic mobilization program. Before (pre-intervention) and after (post-intervention) the programs, patients underwent the following assessments: shoulder range of motion (ROM), in both flexion and extra rotation positions; pain perception (visual analogue scale); simple shoulder test. Results: pre vs. post-intervention results were compared in each group by means of a dependent-samples t-Test on each variables. An independent-samples t-Test was used to analyze pre-intervention differences between TR and WR groups; since no significant differences were found, the same test was used to analyze post-intervention differences. Pre- vs post-intervention results showed significant improvements in all variables in both groups (p 0,005) Discussion: although the water-based program did not result more effective than the traditional program at the end of the three months, the aquatic rehabilitation seemed to improve shoulder ROM faster than the traditional one and to be better tolerated by the patients. It’s authors’ opinion that both evidences may increase the adherence to the program during the rest of the rehabilitation programUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    EQUATION REGRESSION MODEL FOR THE 50 M FREESTYLE PERFORMANCE IN ELITE MASTER SWIMMERS

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    This study was conducted during the 10th World Masters Championships, held in Riccione, Italy, June 3-11, 2004. The aim was to investigate, in male and female elite master swimmers, the relationships between performance time and age, anthropometric characteristics (weight, stature, arm and forearm lengths and forearm volume) and muscle strength (hand grip). Performance times were recorded during 50 m freestyle events. Anthropometric values and hand grip were collected the same day the competition in a field laboratory organised beside the swimming pool. For this study we considered twenty eight volunteers: 15 men aged 42-81 years and 13 women aged 4173 years. Firstly, the anthropometrical characteristics. the hand grip strength and the performance time were used for a simple correlation analysis. Subsequently a multiple regression analysis was carried out to create a swimming time prediction model for the 50 freestyle performances. It revealed that in 50 m freestyle women race, age, weight and strength explained about 97% of the variance in performance. This study provided novel information which could be useful in designing training programs, optimizing swimmer's resources or capabilities

    Impact of Different Developmental Instars on Locusta migratoria Jumping Performance

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    Ontogenetic locomotion research focuses on the evolution of locomotion behavior in different developmental stages of a species. Unlike vertebrates, ontogenetic locomotion in invertebrates is poorly investigated. Locusts represent an outstanding biological model to study this issue. They are hemimetabolous insects and have similar aspects and behaviors in different instars. This research is aimed at studying the jumping performance of Locusta migratoria over different developmental instars. Jumps of third instar, fourth instar, and adult L. migratoria were recorded through a high-speed camera. Data were analyzed to develop a simplified biomechanical model of the insect: the elastic joint of locust hind legs was simplified as a torsional spring located at the femur-tibiae joint as a semilunar process and based on an energetic approach involving both locomotion and geometrical data. A simplified mathematical model evaluated the performances of each tested jump. Results showed that longer hind leg length, higher elastic parameter, and longer takeoff time synergistically contribute to a greater velocity and energy storing/releasing in adult locusts, if compared to young instars; at the same time, they compensate possible decreases of the acceleration due to the mass increase. This finding also gives insights for advanced bioinspired jumping robot design

    Physiological responses to pedaling on a water stationary bike at different immersion heights

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    Only a few studies[1-4] have investigated oxygen consumption (V’O2) and heart rate (HR) responses to pedaling on a stationary bike in water (WSB), while literature is still lacking on the effects elicited by variations in immersion depth. 14 subjects (8 M, 6 F, age 30±6y, weight 67±14kg, BMI 22.8±2.3kg/m2, fat mass 21,4±3%) performed 2 testing sessions and 2 exercise sessions: i) dry-land incremental exercise test (cycle-ergometer) to age-predicted maximum HR (HR); ii) underwater (hip-height) incremental exercise test (on a WSB) to exhaustion; iii/iv) two 2-stage (18-minutes each) underwater pedaling exercises on a WSB (Aqquatix S.r.l., Italy) at 2 different immersion heights (armpit/hip). Breath-by-breath V’O2 and beat-by-beat HR were recorded continuously throughout dry-land sessions. The intensities of the exercise sessions were 45%-55% (stage#1) and 70%-80% (stage#2) of the underwater V’O2 peak (a metronome was set at the V’O2 peak pedaling rate). A repeated-measures (2 exercise intensities) 2-way (armpit/hip heights) ANOVA was performed on each variable and the Bonferroni test was used for post-hoc comparisons. Compared to the hip-height condition, pedaling immersed at the armpit level elicited significantly lower V’O2 and HR (significant solely at high-intensity for HR) responses, either exercising at high (25.5±4.6 vs. 29.1±4.8 mL∙kg-1∙min-1; 127±14 vs. 140±19 beats∙min-1) or low (17.9±3.6 vs. 20.1±3.6 mL∙kg-1∙min-1; 105±16 vs. 110±15 beats∙min-1) intensity. While peak V’O2 didn’t differ significantly between dry-land and underwater tests (36.2±5.4 vs. 38.8±5.8 mL∙kg-1∙min-1), mean HRs at both intensities and both water heights were significantly lower when expressed as percentage of the HR resulting from the underwater test to exhaustion, rather than applying the 220-age prediction equation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Magnetic and thermal properties of 4f-3d ladder-type molecular compounds

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    We report on the low-temperature magnetic susceptibilities and specific heats of the isostructural spin-ladder molecular complexes L2_{2}[M(opba)]_{3\cdot xDMSOâ‹…y\cdot yH2_{2}O, hereafter abbreviated with L2_{2}M3_{3} (where L = La, Gd, Tb, Dy, Ho and M = Cu, Zn). The results show that the Cu containing complexes (with the exception of La2_{2}Cu3_{3}) undergo long range magnetic order at temperatures below 2 K, and that for Gd2_{2}Cu3_{3} this ordering is ferromagnetic, whereas for Tb2_{2}Cu3_{3} and Dy2_{2}Cu3_{3} it is probably antiferromagnetic. The susceptibilities and specific heats of Tb2_{2}Cu3_{3} and Dy2_{2}Cu3_{3} above TCT_{C} have been explained by means of a model taking into account nearest as well as next-nearest neighbor magnetic interactions. We show that the intraladder L--Cu interaction is the predominant one and that it is ferromagnetic for L = Gd, Tb and Dy. For the cases of Tb, Dy and Ho containing complexes, strong crystal field effects on the magnetic and thermal properties have to be taken into account. The magnetic coupling between the (ferromagnetic) ladders is found to be very weak and is probably of dipolar origin.Comment: 13 pages, 15 figures, submitted to Phys. Rev.

    Somatic embryogenesis in Abies nebrodensis, an endangered Sicilian fir

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    Somatic embryogenesis, as a promising biotechnological tool for many conifer trees, has never been applied for the Abies nebrodensis species. Although all the encouraging results previously obtained by the EU LIFE (European LIFE program) funded projects in over ten years, the critically endangered Sicilian fr remains alarmingly close to extinction. In this study, we reported the first protocol of somatic embryogenesis obtained from mature zygotic embryos of the Abies nebrodensis. Seeds from Abies adult trees with specifc identifcation numbers (IN) were collected and full seeds were identifed by X-ray. Diferent experiments were carried out for callus initiation, from both zygotic immature and mature embryos, testing diferent culture media. The immature embryos did not give embryogenic tissue (ET). Embryogenic callus (EC) was successfully induced from mature embryos with variable frequencies (0–40%). Schenk and Hilderbrandt (SH) was the most suitable initiation medium where the obtained callus initiation rate reached up to 40% for IN7 (frst experiment). 6-benzylaminopurine (BAP) showed to be essential to induce EC (second experiment). IN8 presented the highest callus initiation rate (40%) among all tested donor trees, whereas IN13 recorded the lowest rate with 4% (third experiment). ET maturation from each singular embryo of IN7, IN8, IN10 and IN21 was successfully achieved in SH medium containing 37,83 µM abscisic acid (ABA), 8% of polyethylene glycol (PEG-4000) and 4% maltose. The encapsulation technology was assessed on the obtained ET and its proliferation was observed after encapsulation

    Kaposi's Sarcoma and HIV-Tat: Challenges to Antiangiogenesis Research

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    Kaposi's sarcoma (KS) is characterized by an abnormal growth of blood vessels. KS was found mainly in older men of Mediterranean or African origin (classic KS) or in patients after organ transplantation (iatrogenic KS). However, in the early 1980s, an aggressive epidemic form, linked to AIDS, was noticed and was one of the first clues to the existence of HIV-1 pandemy. The link between KS occurrence and HIV has raised multiple hypotheses. The drastic reduction of KS after the introduction of HAART, suggests HIV as a powerful co-factor for KS progression. We and others have contributed to the elucidation of KS cell nature and the possible involvement of extracellular HIV Tat. Tat is proangiogenic and is a true promoter of KS lesions acting as a VEGFR2 ligand both on KS and endothelial cells, in addition Tat is able to bind and activate chemokine receptors on monocytes and granulocytes causing a pro-inflammatory status. Evaluation of the effects of extracellular Tat on KS cells by microarray analysis after 24 h of incubation shows an interesting clustering of gene products involved in signal transduction, especially GTP-ase, Kinase and cAMP activity, confirming that Tat acts extracellularly by ways that are probably unrelated to its nuclear activity. KS occurrence is reduced by HAART but still present and in Africa is one of the most frequent oncologic disease. To find suitable drugs with low toxic impact on KS patients, we have tested several drugs and gene therapy approaches in in vivo models. from 2005 International Meeting of The Institute of Human Virology Baltimore, USA, 29 August – 2 September 200
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