837 research outputs found
The effects of superior ovarian nerve sectioning on ovulation in the guinea pig
The effects on spontaneous ovulation associated with the unilateral or bilateral sectioning of the superior ovarian nerves (SON) were analyzed in guinea pigs at different time intervals of the estrous cycle. Day 1 of the estrous cycle was defined as the day when the animal presents complete loss of the vaginal membrane (open vagina). Subsequent phases of the cycle were determined by counting the days after Day 1. All animals were autopsied on the fifth day of the estrous cycle after surgery. Sectioning the right, left, or both SONs on day 5 (early luteal phase) resulted in a significant increase in the number of fresh corpora lutea. Ovulation increased significantly when the left SON (L-SON) was sectioned during late follicular phase (day 1) and medium luteal phase (day 8). When surgery was performed on days 1 or 8, neither sectioning the right SON (R-SON) nor sectioning the SON bilaterally had an apparent effect on ovulation rates. Similarly, ovulation rates were not affected when unilateral (right or left) or bilateral sectioning of the SON was performed during late luteal phase two (day 12). Unilateral or bilateral sectioning of the SON performed during the early luteal phase (day 5) was associated with a significant decrease in uterine weight. A comparable effect was observed when the L-SON was sectioned during late follicular phase (day 1), or medium luteal phase (day 8). No effects on uterine weight were observed when unilateral or bilateral sectioning of the SON was performed during late luteal phase. Our results suggest that in the guinea pig the SON modulates ovulation, and that the degree of modulation varies along the estrous cycle. The strongest influence of the SONs on ovulation occurs during early luteal phase, and decrease thereafter, being absent by late luteal phase. In addition, sectioning the left or the right SON caused different responses by the ovaries of adult guinea pigs. This paper discusses the mechanisms by which ovulation increased when the SON was surgically cut
Computational Design of Inhibitors Targeting the Catalytic β Subunit of Escherichia coli FOF1-ATP Synthase
With the uncontrolled growth of multidrug-resistant bacteria, there is an urgent need to search for new therapeutic targets, to develop drugs with novel modes of bactericidal action. FoF1-ATP synthase plays a crucial role in bacterial bioenergetic processes, and it has emerged as an attractive antimicrobial target, validated by the pharmaceutical approval of an inhibitor to treat multidrug-resistant tuberculosis. In this work, we aimed to design, through two types of in silico strategies, new allosteric inhibitors of the ATP synthase, by targeting the catalytic β subunit, a centerpiece in communication between rotor subunits and catalytic sites, to drive the rotary mechanism. As a model system, we used the F1 sector of Escherichia coli, a bacterium included in the priority list of multidrug-resistant pathogens. Drug-like molecules and an IF1-derived peptide, designed through molecular dynamics simulations and sequence mining approaches, respectively, exhibited in vitro micromolar inhibitor potency against F1. An analysis of bacterial and Mammalia sequences of the key structural helix-turn-turn motif of the C-terminal domain of the β subunit revealed highly and moderately conserved positions that could be exploited for the development of new species-specific allosteric inhibitors. To our knowledge, these inhibitors are the first binders computationally designed against the catalytic subunit of FOF1-ATP synthase. Keywords: FOF1-ATP synthase; allosteric inhibition; evolutionary and PPI algorithms; peptide design; structure-based drug design
Magnetic Field Measurement with Ground State Alignment
Observational studies of magnetic fields are crucial. We introduce a process
"ground state alignment" as a new way to determine the magnetic field direction
in diffuse medium. The alignment is due to anisotropic radiation impinging on
the atom/ion. The consequence of the process is the polarization of spectral
lines resulting from scattering and absorption from aligned atomic/ionic
species with fine or hyperfine structure. The magnetic field induces precession
and realign the atom/ion and therefore the polarization of the emitted or
absorbed radiation reflects the direction of the magnetic field. The atoms get
aligned at their low levels and, as the life-time of the atoms/ions we deal
with is long, the alignment induced by anisotropic radiation is susceptible to
extremely weak magnetic fields (G). In fact,
the effects of atomic/ionic alignment were studied in the laboratory decades
ago, mostly in relation to the maser research. Recently, the atomic effect has
been already detected in observations from circumstellar medium and this is a
harbinger of future extensive magnetic field studies. A unique feature of the
atomic realignment is that they can reveal the 3D orientation of magnetic
field. In this article, we shall review the basic physical processes involved
in atomic realignment. We shall also discuss its applications to
interplanetary, circumstellar and interstellar magnetic fields. In addition,
our research reveals that the polarization of the radiation arising from the
transitions between fine and hyperfine states of the ground level can provide a
unique diagnostics of magnetic fields in the Epoch of Reionization.Comment: 30 pages, 12 figures, chapter in Lecture Notes in Physics "Magnetic
Fields in Diffuse Media". arXiv admin note: substantial text overlap with
arXiv:1203.557
Fisheries and Prestige. Review and update of studies on the effects of the Prestige oil spill
The Prestige oil tanker sank in November 2002 and leaked around 60 000 mt. of heavy oil (type M-100) into the
sea. Immediately after the accident, closed areas were established. Among the fleets affected by the closures were
four of the most important in ICES Division VIIIc and Sub-division IXa North (bottom trawl, pair trawl, purse seine
targeting sardine and hand line targeting mackerel) as they exploit considerable resources, some outside
biological safety limits. A fall in effort was observed in all of them, mainly in the first quarter and in sub-divisions
VIIIc West and IXa North, although it failed to lead to a very large reduction in the total annual effort of each of the
fleets, with the exception of hand line. Pair trawlers can make two types of fishing trip, but differences in specific
composition among the three years analysed were not found in either of them. In the case of trawl, five kinds of
fishing trips were identified, and changes were only found in the type that targets Norway lobster, hake, megrim
and monk (HMMN), with a fall in the presence of Norway lobster
What is the progenitor of the Type Ia SN 2014J?
We report the deepest radio interferometric observations of the closest Type Ia supernova in decades, SN 2014J, which exploded in the nearby galaxy M 82. These observations
represent, together with radio observations of SNe 2011fe, the most sensitive radio studies of a Type Ia SN ever. We constrain the mass-loss rate from the progenitor system of
SN 2014J lower than 7.0 × 10^(−10) M yr^(−1) (for a wind speed of 100 km s^(−1) ). Our deep upper limits favor a double-degenerate scenario–involving two WD stars–for the progenitor system of SN 2014J, as such systems have less circumstellar gas than our upper limits. By contrast,
most single-degenerate scenarios, i.e., the wide family of progenitor systems where a red giant, main-sequence, or sub-giant star donates mass to a exploding white dwarf, are ruled out by our observations. The evidence from SNe 2011fe and 2014J points in the direction of a double-degenerate scenario for both
Nueva herramienta para la adquisición de conocimientos y evaluaciones en temas de urología: urocenter.net
Carbapenem-resistant Citrobacter spp. isolated in Spain from 2013 to 2015 produced a variety of carbapenemases including VIM-1, OXA-48, KPC-2, NDM-1 and VIM-2
Objectives: There is little information about carbapenemase-producing (CP) Citrobacter spp.We studied the molecular epidemiology and microbiological features of CP Citrobacter spp. isolates collected in Spain (2013-15).
Methods: In total, 119 isolates suspected of being CP by the EUCAST screening cut-off values were analysed. Carbapenemases and ESBLs were characterized using PCR and sequencing. The genetic relationship among Citrobacter freundii isolates was studied by PFGE.
Results: Of the 119 isolates, 63 (52.9%) produced carbapenemases, of which 37 (58.7%) produced VIM-1, 20 (31.7%) produced OXA-48, 12 (19%) produced KPC-2, 2 (3.2%) produced NDM-1 and 1 (1.6%) produced VIM- 2; 9 C. freundii isolates co-produced VIM-1 plus OXA-48. Fourteen isolates (22.2%) also carried ESBLs: 8 CTX-M-9 plus SHV-12, 2 CTX-M-9, 2 SHV-12 and 2 CTX-M-15. Fifty-seven isolates (90.5%) were C. freundii, 4 (6.3%) were Citrobacter koseri, 1 (1.6%) was Citrobacter amalonaticus and 1 (1.6%) was Citrobacter braakii. By EUCAST breakpoints, eight (12.7%) of the CP isolates were susceptible to the four carbapenems tested. In the 53 CP C. freundii analysed by PFGE, a total of 44 different band patterns were observed. Four PFGE clusters were identified: cluster 1 included eight isolates co-producing VIM-1 and OXA-48; blaVIM-1 was carried in a class 1 integron (intI-blaVIM-1 - aacA4-dfrB1-aadA1-catB2-qacE¿1/sul1) and blaOXA-48 was carried in a Tn1999.2 transposon.
Conclusions: We observed the clonal and polyclonal spread of CP Citrobacter spp. across several Spanish geographical areas. Four species of Citrobacter spp. produced up to five carbapenemase types, including coproduction of VIM-1 plus OXA-48. Some CP Citrobacter spp. isolates were susceptible to the four carbapenems tested, a finding with potential clinical implications
Synthesis and Structure of Trinuclear W3S4 Clusters Bearing Aminophosphine Ligands and Their Reactivity toward Halides and Pseudohalides
The aminophosphine ligand (2-aminoethyl)- diphenylphosphine (edpp) has been coordinated to the W3(μ-
S)(μ-S)3 cluster unit to afford trimetallic complex [W3S4Br3(edpp)3]+ (1+) in a one-step synthesis process with high yields. Related [W3S4X3(edpp)3]+ clusters (X = F−, Cl−, NCS−; 2+−4+) have been isolated by treating 1+ with the
corresponding halide or pseudohalide salt. The structure of complexes 1+ to 4+ contains an incomplete W3S4 cubane-type cluster unit, and only one of the possible isomers is formed: the one with the phosphorus atoms trans to the capping sulfur and the amino groups trans to the bridging sulphurs. The remaining coordination position on each metal is occupied by X. Detailed studies using stopped-flow, 31P{1H} NMR, and ESI-MS have been carried out in order to understand the solution behavior and the kinetics of interconversion among species 1+, 2+, 3+, and 4+ in solution. Density functional theory (DFT) calculations have been also carried out on the reactions of cluster 1+ with the different anions. The whole set of experimental and theoretical data indicate that the actual mechanism of substitutions in these clusters is strongly dependent on the nature of the leaving and entering anions. The interaction between an entering F− and the amino group coordinated to the adjacent metal have also been found to be especially relevant to the kinetics of these reactions
Frecuencia y factores de riesgo asociados a sobrepeso y obesidad en universitarios de colima, méxico
Objetivo Determinar la frecuencia y factores de riesgo para sobrepeso y obesidad en jóvenes universitarios. Métodos Se realizó un estudio transversal analítico en 821 alumnos inscritos de la Universidad de Colima. Entre las variables analizadas se encuentran: edad, género, alcoholismo, tabaquismo y utilización de medicamentos o sustancias para control de peso. Resultados Se estudiaron 821 alumnos (380 hombres y 441 mujeres) con una edad promedio de 20,9±2,5 años. Las frecuencias de sobrepeso y obesidad en hombres fueron de 27,8 % y 14,7 % y en mujeres de 17 % y 5,2 %. En hombres el tabaquismo (OR 2,1, IC 95% 1,4-3,8;p=0,01) y etilismo (OR 2,1, IC 95% 1,2-3,6;p=0,003), estuvieron asociados a sobrepeso y obesidad. Fueron factores protectores en ambos géneros el uso de sustancias para control de peso (OR 0,4, IC 95% 0,2-0,8;p=0,01); mientras que el control dietético fue un factor protector sólo en las mujeres (OR 2,2, IC 95% 1,1-3,4;p=0,01). Conclusiones En estudiantes universitarios, el 31,6 % presentó sobrepeso y obesidad. En hombres, el tabaquismo y etilismo se asociaron a sobrepeso y obesidad. El uso de sustancias para bajar de peso y control dietético fueron factores protectores
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