119 research outputs found
LÍQUIDO FOLICULAR FRESCO OU CONGELADO NA PRODUÇÃO IN VITRO DE EMBRIÕES BOVINOS
A manutenção dos complexos cumulus-oócitos (CCO) em líquido folicular (LF) antes da
sua maturação, além de visar a capacitação, viabiliza o transporte até o laboratório por ser de baixo
custo, de fácil aquisição e o congelamento do LF permite seu armazenamento para futura utilização.
Neste experimento avaliou-se o efeito do congelamento do LF obtido de folículos de 2-8mm e de
folículos >8mm, sobre a taxa de produção embrionária. Oócitos foram aspirados de folículos de 2 a
8mm de ovários provenientes de abatedouro. No grupo controle (n=295) os CCO foram maturados
por 24h. Nos tratamentos GF (n=297) e GC (n=282), os CCO foram mantidos por 6h a 30ºC em LF
fresco ou congelado, respectivamente, de folículos >8mm. Já no tratamento PF(n=278) e PC (n=281),
os CCO foram mantidos em LF fresco ou congelado, respectivamente, de folículos de 2-8mm.
Posteriormente, os CCO dos tratamentos GF, GC, PF e PC foram maturados por 18h. Não houve
efeito negativo do congelamento do líquido folicular e nem do tamanho dos folículos sobre as taxas
de clivagem e produção embrionária em D7 e D9 (P>0,05). No entanto, o congelamento do LF de
folículos de 2 a 8mm resultou em redução da taxa de eclosão e do número de células dos blastocistos.
A manutenção de oócitos bovinos por 6h a 30ºC, antes da maturação, pode ser efetuada em líquido
folicular de folículos >8mm, fresco ou congelado.
Fresh or frozen follicular fluid in vitro bovine embryo production
Abstract
In addition to the capacitation, the maintenance of cumulus-oocyte complex (COC) in
follicular fluid (FF) before maturation, allows the transport to the laboratory, being a practical and less
expensive media. The FF can be stored after freezing to future use. Oocytes aspirated from bovine
slaughterhouse ovaries, were used to evaluate the effect of maintaining the oocytes in fresh or frozen
bovine FF (from 2-8mm and >8mm follicles) on the blastocyst rate. In the control group (n=259) the
COC were matured for 24h. On treatments GF (n=297) and GC (n=282) the COC were held for 6h at
30°C in fresh or frozen FF from >8mm follicles, respectively. In treatments PF (n=278) and PC (n=281)
the COC were held in fresh or frozen FF from 2-8mm follicles, respectively. Later, the COC from GF,
GC, PF and PC were matured for 18h. The freezing process as well as the follicle size had no effect
on the cleavage, D7 or D9 blastocyst rates (P>0,05). Nevertheless, the frozen FF from 2-8mm follicles
resulted in a reduced hatching rate and lower ICM cells. Fresh or frozen follicular fluid of >8mm
follicles could be used for a 6h transport of bovine oocytes before maturation for 18h
LÍQUIDO FOLICULAR FRESCO OU CONGELADO NA PRODUÇÃO IN VITRO DE EMBRIÕES BOVINOS
A manutenção dos complexos cumulus-oócitos (CCO) em líquido folicular (LF) antes da
sua maturação, além de visar a capacitação, viabiliza o transporte até o laboratório por ser de baixo
custo, de fácil aquisição e o congelamento do LF permite seu armazenamento para futura utilização.
Neste experimento avaliou-se o efeito do congelamento do LF obtido de folículos de 2-8mm e de
folículos >8mm, sobre a taxa de produção embrionária. Oócitos foram aspirados de folículos de 2 a
8mm de ovários provenientes de abatedouro. No grupo controle (n=295) os CCO foram maturados
por 24h. Nos tratamentos GF (n=297) e GC (n=282), os CCO foram mantidos por 6h a 30ºC em LF
fresco ou congelado, respectivamente, de folículos >8mm. Já no tratamento PF(n=278) e PC (n=281),
os CCO foram mantidos em LF fresco ou congelado, respectivamente, de folículos de 2-8mm.
Posteriormente, os CCO dos tratamentos GF, GC, PF e PC foram maturados por 18h. Não houve
efeito negativo do congelamento do líquido folicular e nem do tamanho dos folículos sobre as taxas
de clivagem e produção embrionária em D7 e D9 (P>0,05). No entanto, o congelamento do LF de
folículos de 2 a 8mm resultou em redução da taxa de eclosão e do número de células dos blastocistos.
A manutenção de oócitos bovinos por 6h a 30ºC, antes da maturação, pode ser efetuada em líquido
folicular de folículos >8mm, fresco ou congelado.
Fresh or frozen follicular fluid in vitro bovine embryo production
Abstract
In addition to the capacitation, the maintenance of cumulus-oocyte complex (COC) in
follicular fluid (FF) before maturation, allows the transport to the laboratory, being a practical and less
expensive media. The FF can be stored after freezing to future use. Oocytes aspirated from bovine
slaughterhouse ovaries, were used to evaluate the effect of maintaining the oocytes in fresh or frozen
bovine FF (from 2-8mm and >8mm follicles) on the blastocyst rate. In the control group (n=259) the
COC were matured for 24h. On treatments GF (n=297) and GC (n=282) the COC were held for 6h at
30°C in fresh or frozen FF from >8mm follicles, respectively. In treatments PF (n=278) and PC (n=281)
the COC were held in fresh or frozen FF from 2-8mm follicles, respectively. Later, the COC from GF,
GC, PF and PC were matured for 18h. The freezing process as well as the follicle size had no effect
on the cleavage, D7 or D9 blastocyst rates (P>0,05). Nevertheless, the frozen FF from 2-8mm follicles
resulted in a reduced hatching rate and lower ICM cells. Fresh or frozen follicular fluid of >8mm
follicles could be used for a 6h transport of bovine oocytes before maturation for 18h
Scalar Field Dark Matter
This work is a review of the last results of research on the Scalar Field
Dark Matter model of the Universe at cosmological and at galactic level. We
present the complete solution to the scalar field cosmological scenario in
which the dark matter is modeled by a scalar field with the scalar
potential and the
dark energy is modeled by a scalar field , endowed with the scalar
potential , which together compose the 95% of the total
matter energy in the Universe. The model presents successfully deals with the
up to date cosmological observations, and is a good candidate to treat the dark
matter problem at the galactic level.Comment: 11 pagez, 5 figures, REVTeX. To appear in proceedings of the
``Mexican Meeting on Exact Solutions and Scalar Fields in Gravity '', in
honour of Heinz Dehnen's 65th Birthday and Dietrich Kramer's 60th Birthday.
Mexico D.F., Mexico, in press. More info at
http://www.fis.cinvestav.mx/~siddh/PHI
Attractive subfamilies of BLS curves for implementing high-security pairings
Barreto-Lynn-Scott (BLS) curves are a stand-out candidate for implementing high-security pairings. This paper shows that particular choices of the pairing-friendly search parameter give rise to four subfami- lies of BLS curves, all of which offer highly efficient and implementation- friendly pairing instantiations. Curves from these particular subfamilies are defined over prime fields that support very efficient towering options for the full extension field. The coefficients for a specific curve and its correct twist are automat-ically determined without any computational effort. The choice of an extremely sparse search parameter is immediately reflected by a highly efficient optimal ate Miller loop and final exponentiation. As a resource for implementors, we give a list with examples of implementation-friendly BLS curves through several high-security levels
In Beam Tests of Implanted Helium Targets
Targets consisting of 3,4He implanted into thin aluminum foils (approximately
100, 200 or 600 ug/cm^2) were prepared using intense (a few uA) helium beams at
low energy (approximately 20, 40 or 100 keV). Uniformity of the implantation
was achieved by a beam raster across a 12 mm diameter tantalum collimator at
the rates of 0.1 Hz in the vertical direction and 1 Hz in the horizontal
direction. Helium implantation into the very thin (approximately 80-100
ug/cm^2) aluminum foils failed to produce useful targets (with only
approximately 10% of the helium retained) due to an under estimation of the
range by the code SRIM. The range of low energy helium in aluminum predicted by
Northcliffe and Shilling and the NIST online tabulation are observed on the
other hand to over estimate the range of low energy helium ions in aluminum. An
attempt to increase the amount of helium by implanting a second deeper layer
was also carried out, but it did not significantly increase the helium content
beyond the blistering limit (approximately 6 x 10^17 helium/cm^2). The
implanted targets were bombarded with moderately intense 4He and 16O beams of
50-100 particle nA . Rutherford Back Scattering of 1.0 and 2.5 MeV proton beams
and recoil helium from 15.0 MeV oxygen beams were used to study the helium
content and profile before, during and after bombardments. We observed the
helium content and profile to be very stable even after a prolonged bombardment
(up to two days) with moderately intense beams of 16O or 4He. Helium implanted
into thin (aluminum) foils is a good choice for thin helium targets needed, for
example, for a measurement of the 3he(a,g)7Be reaction and the associated S34
astrophysical cross section factor (S-factor).
Comment: Submitted to the New Online Journal of Instrumentation, JINST. Work
Supported by USDOE Grant Nos: DE-FG02-94ER40870, DE-FG02-91ER40609,
DE-FG02-97ER41033, and DE-FG02-97ER4104
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