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1.
Nature ; 621(7980): 716-722, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37758891

RESUMO

Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.

2.
J Appl Stat ; 47(13-15): 2912-2926, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-35707421

RESUMO

Dengue fever is a viral disease transmitted by the mosquito Aedes aegypti. In order to avoid epidemics and deaths, this transmitting vector must be controlled. This work assembles, for the first time, data from multiple governmental bodies describing the number of dengue cases reported, and meteorological conditions in 20 cities in the Goiás state, Brazil, from 2008 to 2015. We then apply generalised linear mixed modelling to this novel data set to model dengue occurrences in this state, where the tropical climate favours the proliferation of the main transmitting vector of this disease. The number of reported dengue cases is estimated using meteorological variables as fixed effects, and city and year data are included in the model as random effects. The proposed models can cope with complex data structures, such as nested data, while taking into account the particularities of each year dependent on the city under analysis. The results confirm that precipitation, minimum temperature, and relative air humidity contribute to the increase of dengue cases number, while year and city location are determining factors. Public policies, based on these new results, together with joint actions involving local populations, are essential to combat the vector transmitting dengue and avoid epidemics.

3.
Braz. j. med. biol. res ; 52(1): e7581, 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-974275

RESUMO

Bredemeyera floribunda roots are popularly used to treat snakebites in the semiarid region of Northeast Brazil, and previous studies indicate the anti-ophidian actions of triterpenoid saponins found in its roots. To assess B. floribunda root extract (BFRE) activity against the effects of Bothrops jararacussu venom (BjuV), antiphospholipasic, antiproteolytic, antihemorrhagic, antinecrotic, and anti-edematogenic activities were investigated in mice. Phytochemical analysis revealed the presence of saponins, flavonoids, and sugars, with rutin and saccharose being the major constituents of BFRE. Acute toxicity was determined and BFRE was nontoxic to mice. Phospholipase A2 and proteolytic activities induced by BjuV were inhibited in vitro by BFRE at all concentrations tested herein. BFRE (150 mg/kg) inhibited paw edema induced by BjuV (50 µg/animal), reducing total edema calculated by area under the curve, but carrageenan-induced paw edema was unchanged. Hemorrhagic and necrotizing actions of BjuV (50 µg/animal) were considerably decreased by BFRE treatment. Thus, BFRE blocked the toxic actions of B. jararacussu venom despite having no anti-inflammatory activity, which points to a direct inhibition of venom's toxins, as demonstrated in the in vitro assays. The larger amounts of rutin found in BFRE may play a role in this inhibition, since 3′,4′-OH flavonoids are known inhibitors of phospholipases A2.


Assuntos
Animais , Masculino , Ratos , Antivenenos/farmacologia , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Venenos de Crotalídeos/antagonistas & inibidores , Edema/tratamento farmacológico , Hemorragia/etiologia , Antivenenos/isolamento & purificação , Bothrops , Venenos de Crotalídeos/toxicidade , Polygalaceae/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Edema/etiologia , Hemorragia/tratamento farmacológico
4.
Braz J Med Biol Res ; 52(1): e7581, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30517287

RESUMO

Bredemeyera floribunda roots are popularly used to treat snakebites in the semiarid region of Northeast Brazil, and previous studies indicate the anti-ophidian actions of triterpenoid saponins found in its roots. To assess B. floribunda root extract (BFRE) activity against the effects of Bothrops jararacussu venom (BjuV), antiphospholipasic, antiproteolytic, antihemorrhagic, antinecrotic, and anti-edematogenic activities were investigated in mice. Phytochemical analysis revealed the presence of saponins, flavonoids, and sugars, with rutin and saccharose being the major constituents of BFRE. Acute toxicity was determined and BFRE was nontoxic to mice. Phospholipase A2 and proteolytic activities induced by BjuV were inhibited in vitro by BFRE at all concentrations tested herein. BFRE (150 mg/kg) inhibited paw edema induced by BjuV (50 µg/animal), reducing total edema calculated by area under the curve, but carrageenan-induced paw edema was unchanged. Hemorrhagic and necrotizing actions of BjuV (50 µg/animal) were considerably decreased by BFRE treatment. Thus, BFRE blocked the toxic actions of B. jararacussu venom despite having no anti-inflammatory activity, which points to a direct inhibition of venom's toxins, as demonstrated in the in vitro assays. The larger amounts of rutin found in BFRE may play a role in this inhibition, since 3',4'-OH flavonoids are known inhibitors of phospholipases A2.


Assuntos
Antivenenos/farmacologia , Venenos de Crotalídeos/antagonistas & inibidores , Edema/tratamento farmacológico , Hemorragia/etiologia , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Polygalaceae/química , Animais , Antivenenos/isolamento & purificação , Bothrops , Venenos de Crotalídeos/toxicidade , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Edema/etiologia , Hemorragia/tratamento farmacológico , Masculino , Ratos
5.
J Chem Phys ; 149(8): 084201, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30193491

RESUMO

We demonstrate the production of cryogenic beams of heteronuclear molecules from the matrix isolation sublimation (MISu) technique. A sapphire mirror serves as a substrate whereupon a solid Ne matrix is grown. Atoms of Li, H, Ca, and C are implanted into the matrix via subsequent laser ablation of different solid precursors such as Ca, Li, LiH, and graphite. The matrix is sublimated into vacuum generating a cryogenic beam of Ne carrying the previously isolated neutral atomic and molecular species. A compact and low energy electron source and time-of-flight mass spectrometer was designed to fit this system at low temperature. With electron ionization time-of-flight mass spectrometry, we analyze the species coming from MISu and demonstrate the formation of heteronuclear molecules in the matrix. In this first study, we produced LiCa from the sequential implantation of Li and Ca into the matrix and some clusters of CnLim after Li and C ablation. Also from ablation of a single LiH pellet, we observed clusters of LinHm. This novel technique opens up the opportunity to generate cryogenic beams of different molecules for precision physics and chemistry studies. Laser or microwave high resolution spectroscopy of a molecular beam benefits from low translational and rovibrational temperatures and forward velocities, such as the ones produced in this technique. Toward the prospect of enhancing the molecular formation, we introduce a new method to study the atomic diffusion of Li and Ca in the Ne matrix via laser spectroscopy during sublimation. We estimate a small diffusion coefficient at 7 K, but a surprisingly linear atomic dispersion during sublimation. The method is extensive to other species and matrices.

6.
Rev Sci Instrum ; 88(6): 063104, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28668005

RESUMO

We present the development of a mount that accommodates a mirror and a piezoelectric actuator with emphasis on physical needs for low temperature operation. The design uses a monolithic construction with flexure features that allow it to steadily hold the mirror and the piezoelectric actuator without glue and accommodate differential thermal contraction. The mount is small and lightweight, adding little heat capacity and inertia. It provides a pre-loading of the piezoelectric actuator as well as a good thermal connection to the mirror and a thermal short across the piezoelectric actuator. The performance of the assemblies has been tested by thermally cycling from room temperature down to 3 K more than a dozen times and over one hundred times to 77 K, without showing any derating. Such mounts are proposed for the cryogenic optical enhancement cavities of the ALPHA experiment at CERN for laser spectroscopy of antihydrogen and for hydrogen spectroscopy in our laboratory at UFRJ.

7.
Arq. bras. med. vet. zootec ; 68(5): 1316-1324, set.-out. 2016. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-827879

RESUMO

Objetivou-se com este trabalho avaliar os efeitos da temperatura e do tempo de armazenamento de amostras de leite cru refrigerado nos resultados das análises eletrônicas da qualidade do leite. Amostras de leite cru refrigerado foram coletadas de tanques de expansão de uso individual de fazendas localizadas na mesorregião Centro Goiano, no estado de Goiás, e armazenadas em quatro temperaturas diferentes (3°C, 11°C, 17°C e 25°C) durante 16 dias. Foram realizadas diariamente análises de contagem bacteriana total (CBT), contagem de células somáticas (CCS) e composição química. Os resultados obtidos foram submetidos à análise de variância em esquema de parcelas subdivididas no tempo em delineamento de blocos ao acaso, e as médias comparadas pelo teste de Duncan. Concluiu-se que as amostras destinadas à análise de CBT, adicionadas do conservante azidiol, podem ser analisadas por até 16 dias após a coleta, quando armazenadas em temperaturas de 3°C e 11°C, e por até 10 dias, quando armazenadas a 17°C. As amostras destinadas às análises de CCS e composição química, adicionadas do conservante bronopol, podem ser analisadas por até 16 dias após a coleta, quando armazenadas em temperaturas de 3°C e 11°C, e por até sete dias, quando armazenadas a 17°C.(AU)


The aim of this study was to evaluate the effects of temperature and storage time of cooled samples of raw milk on the results of milk quality electronic analysis. Refrigerated raw milk samples were collected from expansion tanks for individual use of farms located in the middle region of the state of Goiás, and stored at four different temperatures (3°C, 11°C, 17°C, and 25°C) for 16 days. Total bacterial count (TBC), somatic cell count (SCC), and chemical composition were performed daily. The results were submitted to analysis of variance in split plot design in randomized blocks, and the means were compared by Duncan test. We concluded that, when azidiol is added as preservative to samples for TBC, they can be analyzed up to 16 days after collection when stored at temperatures of 3°C and 11°C, and up to 10 days when stored at 17°C. Moreover, when bronopol is added as preservative, samples for SCC and chemical composition analysis can be stored for up to 16 days after collection when stored at temperatures of 3°C and 11°C, and for up to seven days when stored at 17°C.(AU)


Assuntos
Alimentos Resfriados , Conservantes de Alimentos/análise , Leite/química , Leite/microbiologia , Carga Bacteriana , Citometria de Fluxo , Armazenamento de Alimentos , Alimentos Crus/microbiologia , Temperatura
8.
Theriogenology ; 85(3): 540-54, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26553567

RESUMO

The present study evaluated functional aspects of binder of sperm 1 (BSP1) in the bovine species. In a first experiment, cumulus-oocyte complexes (n = 1274) were incubated with frozen-thawed ejaculated sperm (18 hours) in Fert-TALP medium containing: heparin, 10, 20, or 40 µg/mL BSP1. Heparin followed by gelatin affinity chromatography was used for purification of BSP1 from bovine seminal vesicle fluid. With ejaculated sperm, cleavage rates were similar when Fert-TALP medium was incubated with heparin (74.1 ± 2.7%), 10 µg/mL BSP1 (77.8 ± 3.1%), or 20 µg/mL BSP1 (74 ± 2.0%). Day-7 blastocyst rates were equivalent after incubations with heparin (40.8 ± 5.0%) and 10 µg/mL BSP1 (34.1 ± 4.4%), but reduced after 20 µg/mL BSP1 (22.4 ± 2.9%) and 40 µg/mL BSP1 (19.3 ± 4.1%; P < 0.05). In the second experiment, cumulus-oocyte complexes (n = 1213) were incubated with frozen-thawed cauda epididymal sperm (18 hours) in Fert-TALP medium containing: no heparin, heparin, 10, 20, or 40 µg/mL. Cleavage and blastocyst rates were similar after treatments with heparin (68.5 ± 1.3% and 24.7 ± 3.2%, respectively) or without heparin (65.5 ± 1.8% and 27.3 ± 1.6%, respectively). Cleavage was higher after treatment with any BSP1 concentrations (74.2 ± 2.7%-79.0 ± 1.1%) than without heparin (P < 0.05). Also, cleavage was better after Fert-TALP medium incubation with 40 µg/mL BSP1 (79.0 ± 1.1%) than with heparin (68.5 ± 1.3%; P < 0.05). Embryo development was higher (P < 0.05) after treatment with 20 µg/mL BSP1 (35.6 ± 2.5%) and 40 µg/mL (41.1 ± 2%) than after incubations with heparin (24.7 ± 3.2%) or without heparin (27.3 ± 1.6%). Interestingly, BSP1 did not cause reductions in blastocyst rates after fertilization with epididymal sperm, as observed with ejaculated sperm. On the basis of immunocytochemistry, there was BSP1 binding to frozen-thawed ejaculated but not to epididymal sperm. Also, anti-BSP1 reaction remained on ejaculated sperm (as expected) and appeared on epididymal sperm after incubation with purified BSP1. Acrosome reaction of ejaculated and epididymal sperm was induced after incubation with purified BSP1 as well, indicating an effect of BSP1 on capacitation. In conclusion, purified BSP1 from bull seminal vesicles was able to bind to and induce capacitation of ejaculated and epididymal sperm. Also, BSP1 added to fertilization media and allowed proper cleavage and embryo development, with the effects being modulated by previous exposure or not of spermatozoa to seminal plasma.


Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Fertilização in vitro/veterinária , Proteínas Secretadas pela Vesícula Seminal/isolamento & purificação , Proteínas Secretadas pela Vesícula Seminal/farmacologia , Espermatozoides/fisiologia , Reação Acrossômica/efeitos dos fármacos , Animais , Blastocisto/fisiologia , Bovinos , Criopreservação/veterinária , Meios de Cultura , Células do Cúmulo/fisiologia , Ejaculação , Epididimo/citologia , Feminino , Fertilização in vitro/métodos , Heparina/farmacologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Masculino , Oócitos/fisiologia , Preservação do Sêmen/veterinária , Proteínas Secretadas pela Vesícula Seminal/metabolismo , Capacitação Espermática/efeitos dos fármacos , Espermatozoides/metabolismo
9.
Rev Sci Instrum ; 86(7): 073109, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26233358

RESUMO

We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H2 are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

10.
Arq. bras. med. vet. zootec ; 61(2): 515-519, abr. 2009. ilus, tab
Artigo em Português | LILACS | ID: lil-518739

RESUMO

Radiographic exams still the main form to evaluate small bowel in all its extension, and when surveyprojections are not diagnostic, barium series are used although its sensibility can be imitated by filledoverlapped loops, difficulting detailed mucosa visualization. The objective of this study was to adjust anexam technique with intestinal double-contrast, based on techniques used in the human medicine, whichresulted satisfactorily in the demonstration of the mucosal surface in the 30 dogs submitted to the exam.The double-contrast in the lumen was achieved by a combination of a positive contrast medium,recovering the mucosal surface, and a negative filling the lumen. Ambient air and carboximethylcelullosewere the negative contrast medium tested and both were radiographicaly similar.


Assuntos
Animais , Diagnóstico por Imagem , Cães , Intestino Delgado , Radiologia/métodos
11.
Arq. bras. med. vet. zootec ; 60(4): 843-850, ago. 2008. ilus, graf, tab
Artigo em Português | LILACS | ID: lil-489826

RESUMO

Foram utilizadas 28 aves adultas, separadas aleatoriamente em quatro grupos. Os pombos foram anestesiados com isoflurano para a realização da osteotomia diafisária transversa do úmero direito. No grupo I, a osteossíntese foi realizada associando-se dois pinos de Kirschner e polimetilmetacrilato, intramedulares; no grupo II, os pinos de Kirschner foram substituídos por pinos de Schanz; no grupo III, foram utilizados apenas dois pinos de Kirschner; e, no grupo IV, apenas dois pinos de Shanz. Os tempos médios para a consolidação óssea foram de 29±4,04 dias no grupo I; 24±5,29 dias no grupo II; 33±3,74 dias no grupo III; e 32,9±5,21 dias no grupo IV. Foi observada migração dos pinos em 42,9 por cento dos animais do grupo I, em 0 por cento nos do grupo II, em 85,7 por cento nos do grupo III, e em 28,6 por cento nos do grupo IV. Em duas aves dos grupos I, III e IV notou-se incapacidade de voar. Os resultados demonstram que a associação de dois pinos de Schanz e polimetilmetacrilato, ambos intramedulares, é um método efetivo para osteossíntese de úmero em pombos domésticos (Columba livia), proporcionando rápida consolidação óssea e mínimas complicações.


Twenty-eight adult domestic pigeons (Columba livia) were randomly divided into four groups of seven birds each. Anesthesia was performed with isoflurane and oxygen, and an osteotomy of the right humerus midshaft was performed with an electric cutter. On the sequence, one of the following treatments was chosen: group I, two Kirschner pins and polymethylmethacrylate intramedullary; group II, two Schanz pins and polymethylmethacrylate intramedullary; group III, two Kirschner pins only; and group IV, two Schanz pins only. The mean time ± standard deviation for fracture healing was 29±4.04 days in group I; 24±5.29 days in group II; 33±3.74 days in group III; 32.9±5.21 days in group IV. Pin migration was observed in 42.9 percent of the group I animals, 0 percent of group II, 85.7 percent of group III, and 28.6 percent of group IV. Two pigeons of groups I, III, and IV presented flight incapability. The results suggest that two Schanz pins and polymethylmethacrylate intramedullary are an effective method of humeral ostheosynthesis in domestic pigeons (Columba livia), resulting in faster fracture healing with minimal complications.


Assuntos
Animais , Pinos Ortopédicos , Columbidae , Fixação de Fratura/veterinária , Úmero , Ortopedia/veterinária , Cirurgia Veterinária
12.
Hig. aliment ; 18(124): 62-67, set. 2004. tab
Artigo em Português | LILACS | ID: lil-394003

RESUMO

Objetivou-se com o presente estudo avaliar a influência da temperatura de armazenamento e do sistema de utilização do tanque de refrigeração sobre a qualidade microbiológica do leite cru. Foram analisadas 1.215 amostras quanto a contagem bacteriana total (CBT), através da metodologia de citometria de fluxo. Nas amostras abaixo de 4,0ºC , entre 4,1 e 7,0ºC e acima de 7,0ºC a CBT média foi 2.733.000 UFC / ml, 3.641.000 UFC / ml e 5.687.000 UFC / ml, respectivamente. A CBT média das amostras provenientes de tanques coletivos foi 5.536.000 UFC / ml e das colhidas em tanques individuais foi 2.604.000 UFC / ml, sendo significativamente diferente (p<0,05). Observou-se que 70,21 por cento das amostras analisadas apresentaram CBT abaixo de 1.000.000 de UFC / ml. A baixa qualidade microbiológica das amostras sugere predominantemente a ocorrência de falhas na higiene de ordenha.


Assuntos
Conservação de Alimentos , Leite , Temperatura
13.
Phys Rev Lett ; 90(14): 143601, 2003 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-12731915

RESUMO

We consider multimode two-photon interference at a beam splitter by photons created by spontaneous parametric down-conversion. The resulting interference pattern is shown to depend upon the transverse spatial symmetry of the pump beam. In an experiment, we employ the first-order Hermite-Gaussian modes in order to show that, by manipulating the pump beam, one can control the resulting two-photon interference behavior. We expect these results to play an important role in the engineering of quantum states of light for use in quantum information processing and quantum imaging.

14.
Mem Inst Oswaldo Cruz ; 95(1): 83-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10656710

RESUMO

In order to determine the best type of rabies vaccine to use as a booster, 78 serological samples from singly vaccinated cattle were analyzed by counterimmunoelectrophoresis technique. The animals were divided into several groups, received the first vaccine dose with modified live virus vaccine (ERA strain) and were revaccinated with inactivated virus or modified live virus vaccines. Boosters were given at 2, 4, 8, 12 and 16 weeks following first vaccination. Results showed high titres in the cases of booster with inactivated vaccine. In all cases, however, detectable antibody titres declined quickly.


Assuntos
Bovinos/imunologia , Imunização Secundária/veterinária , Vacina Antirrábica/imunologia , Animais , Anticorpos Antivirais/análise , Contraimunoeletroforese , Vírus da Raiva/imunologia , Fatores de Tempo
15.
Rev Soc Bras Med Trop ; 32(5): 533-40, 1999.
Artigo em Português | MEDLINE | ID: mdl-10881088

RESUMO

In order to evaluate the immune response produced by rabies vaccines in new world nonhuman primates, thirty marmosets (Callithrix sp) were divided into five groups of six individuals and submitted to five different antirabies vaccination schemes using two distinct commercially available animal vaccines. The first was produced in suckling mouse brain (Fuenzalida and Palacios), and the second in NIL-2 cell culture. Post-vaccine serological monitoring was carried out periodically. The results showed that the Fuenzalida and Palacios vaccine was not able to protect the animals when using a single dose or even with a booster. But when submitted to a vaccination routine similar to that used for humans, the marmosets showed detectable antibodies, and only one succumbed to rabies after being challenged. In addition, the vaccine produced in NIL-2 cell culture induced high antibody levels in all vaccinated animals and all animals survived the viral challenge.


Assuntos
Anticorpos Antivirais/biossíntese , Callithrix/imunologia , Vacina Antirrábica/imunologia , Animais , Feminino , Masculino
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